Microsoft Word - 192wang.doc VOL. Guest E Copyrig ISBN 9 Anto Schoo SP, Br guira@ Due t receiv first to consu proce can b SCWG produ strate applie of the sugar Both p in com to 2 ( reacta system 1. Int Harve enviro utiliza agricu Algae photo highe Sugar 25 % micro and va The in the us for wa SCWG produ as a group CHE . 37, 2014 Editors: Eliseo Ran ght © 2014, AIDIC 978-88-95608-28- Thermo Su onio C.D. F ol of Chemical E razil @feq.unicamp to the increas ved much atte o be used in c umed when th sses, like as e used as a r G is related to ction in the sy gy to promot ed in the minim e use of CH4 a rcane bagasse problems were mbination with (ideal for Fisc ant. The calcu ms, thus indic troduction esting energy onment is of ation of differe ultural wastes e have been synthetic effic r than that for rcane bagasse hemicellulose bial processes alue added ga nterest in supe sage of superc aste treatmen G is related to ction in the sy strategy to pr p the use of C EMICAL EN nzi, Katharina Koh C Servizi S.r.l., 0; ISSN 2283-92 odynam upercritic Freitas, Re ngineering, Uni p.br sing price and ention in recen onventional th he biomass a supercritical reaction mediu o present larg ystem and thu te syngas pro mization of Gib and CO2 as co e. The Virial e e formulated a h the CONOPT cher-Tropsch ulated final te ating low ener from carbon even greater nt energy sou and many oth proposed as ciency of alga terrestrial pla e is the major e and 25 % lig s as well as e ases (Ahmed a ercritical fluids critical water f t or supercriti o present larg ystem and thu romote synga CO2 and CH4 NGINEERI se- Höinghaus 16 ic Effect cal Wate ginaldo Gu versity of Camp d decreasing nt years. Biom hermochemica re dried. In o water gasifica um, so that we ge hydrogen y s the syngas oduction in SC bbs energy an o-reactant in th equation of st as optimizatio T solver, were synthesis app emperatures w rgy requireme neutral sour importance. urces mixes, in her alternative a biomass ae for converti nts (Ross et a r by-product o gnin. Due to its nergy convers and Gupta, 20 s began in the for biomass co cal water (SC ge hydrogen y us the produc as production co-reactants ING TRAN t of Co-r er Gasifi uirardello* pinas (UNICAM amount of fo mass generally al gasification order to avoid ation (SCWG) et biomass do yields, but the production is CWG process nd in entropy m he SCWG of m tate was used on problems (n e used to solv plications) wa were close to ents for mainta rces with sim It is expecte ncluding biom sources. energy sourc ing atmosphe al., 2009). of the sugar c s abundant av sion via comb 012). e late 1970s a onversion tec CW) gasificatio yields, but the ction of syngas in SCWG pro proved to be NSACTION reactant ication o P), Av. Albert E ossil fuels, ene y contains mu process. How the drying p ), has attracte oes not need excess of wa very low. The ses. In this w maximization t microalgae bio d to represent non-linear prog e them. Synga as obtained w the initial tem ain these react multaneous red d that future mass, municipa ce for hydrog ric CO2 into b ane industry. vailability, it ca ustion or gasi and remains to hnologies suc on for biofuel excess of wa s is very low. ocesses. In p effective to p NS o t Additio of Bioma instein 500, 130 ergy obtained uch water and wever, a large rocess, hydro ed more atten in the dried to ater inhibits th use of co-rea work optimizat to study the th omass (Nanno t the non-idea graming) and as with a H2/C with an additio mperature of t tions. duction of ga energy use w al solid waste gen and biofu biomass is as It contains ab an serve as a fication for the oday. This inte ch as supercrit production (B ater inhibits th The use of co reviously pub promote the sy A publica The Italian Asso of Chemical Engin www.aid on in the ass 083-852, Camp d from biomas d they must be amount of en othermal gasifi ntion because o be processe he carbon mo actants appea ation techniqu hermodynamic ochloropsis sp ality of the sy the software CO molar ratio on of CO2 as the reaction i as emissions will have incr es, industrial w uel production s much as ten bout 50 % cel n ideal substr e production o erest has also tical water ox Brunner, 2009 he carbon mo o-reactants ap blished works yngas produc ation of ociation neering ic.it/cet inas- ss has e dried ergy is fication e water ed. The noxide rs as a es are c effect p.) and stems. GAMS o close s a co- n both to the reased wastes, n. The n times lulose, rate for of fuels o led to idation 9). The noxide ppears of our ction in DOI: 10.3303/CET1437029 Please cite this article as: Daltro de Freitas A.C., Guirardello R., 2014, Thermodynamic effect of co-reactant addition in the supercritical water gasification of biomass, Chemical Engineering Transactions, 37, 169-174 DOI: 10.3303/CET1437029 169 SCWG of glucose and cellulose (Freitas and Guirardello, 2012a) and in SCWG of microalgae biomass from C. vulgaris and Spirulina sp. (Freitas and Guirardello, 2013). In this work, optimization techniques are applied in the minimization of Gibbs energy and in the entropy maximization to study the thermodynamic effect of CH4 and CO2 use as co-reactant in the SCWG of microalgae biomass (Nannochloropsis sp.) and sugarcane bagasse. The Virial equation of state was used to represent the non-ideality of the system. Both problems were formulated as optimization problems (non- linear programing) and the software GAMS in combination with the CONOPT solver, were used to solve them. 2. Methodology 2.1. Gibbs energy minimization – Isothermic systems The thermodynamic equilibrium condition for reactive multicomponent closed system, at constant pressure (P) and temperature (T), with given initial composition, can be obtained by minimization of Gibbs energy (G) of the system, given by: (1) While satisfying the restrictions of non-negative number of moles of each component in each phase: (2) In addition, the restriction of mole balances, given by atom balance for reactive systems: (3) The Gibbs energy minimization was applied to evaluate the behaviour of SCWG systems as regards the composition of products for isothermic systems. Thus, the best operating conditions with respect to temperature, composition of biomass and co-reactants in the feed stream can be determined in order to obtain the highest syngas productivity. 2.2. Entropy maximization – Adiabatic systems The thermodynamic equilibrium condition for reactive multicomponent closed systems, at constant P and enthalpy (H), with given initial composition, can be obtained by maximization of the entropy (S) of the system, with respect to : (4) While satisfying the same previous restrictions, given by equations (2) and (3). Usually, physical properties are given as functions of composition, pressure and temperature, not enthalpy. Therefore, an additional restriction, referent to enthalpy balance, must be satisfied: (5) The entropy maximization method was applied to study the thermal characteristics of the SCWG systems in adiabatic systems. The thermal effect of co-reactants addition was analysed too, in order to determine the better thermal conditions in the SCWG systems. 2.3. Equation of state Since the system analyzed by the present work was at high pressure, the virial equations of state (EoS), truncated at second virial coefficient, were used to determine the fugacity coefficient of the systems. The second virial coefficient is calculated by the correlation of Pitzer and Curl (1957), which was modified by Tsonopoulos (1974). The following relation determined the fugacity coefficient: (6)    = = = ++= NC i NC i NC i s i s i l i l i g i g i nnnG 1 1 1 min μμμ 0,, ≥s i l i g i nnn ( )  = = ==++ NC i NC i imi s i l i g imi NEmnannna 1 1 0 ,...,1 k in    = = = ++= NC i NC i NC i s i s i l i l i g i g i SnSnSnS 1 1 1 max ( ) ( ) == ==++ NC i ii NC i s i s i l i l i g i g i HHnHnHnHn 1 000 1 RT PBBy m j ijji       −= 2ˆln φ 170 Detail well a Guira for mi 3. Re The G exper in the metha therm Nanno (entro 3.1. T In Fig Nanno tempe The c The a H/C m CH4 a The b the ad produ Figure Nanno bioma Figure Nanno N um be r of m ol es s about the fo as the validati rdello (2012a, croalgae Nan esults and d Gibbs energy rimental and s e SCWG of m ane (Freitas a modynamic eff ochloropsis sp opy maximizat Thermodynam gure 1 the co ochloropsis sp erature, the pr co-reactants ad addition of CH4 molar ratio in t addition too; th behavior was v ddition of bot ction, and larg e 1. Effect of c ochloropsis sp ass compositio e 2. Effect of ochloropsis sp 0 0.5 1 1.5 2 2.5 H2 Without With 15 With 25 With 35 With 15 With 25 With 35 973. 1073. 1173. T em pe ra tu re (K ) ormulation and ion of the mo , 2012b and 2 nochloropsis s iscussion minimization simulated data microalgae bio and Guirardell fect of the a p. and sugarc ion) systems. mic effect of c mposition of t p. in Figure 1 ressure and th ddition was an 4 resulted in a the feed strea his behavior c very similar fo th CH4 and C ge amounts of co-reactant ad p. and (b) sug on: 15 wt%. reaction temp p. and sugarca CO co-reactant wt% of CH4 wt% of CH4 wt% of CH4 wt% of CO2 wt% of CO2 wt% of CO2 0 15 15 15 d solution of th odels with exp 2013). The co sp. (Guan et a and entropy a for the SCW omass (Freitas o, 2012b). In addition of C cane bagasse co-reactant a the main gas 1 (a) and for he inlet bioma nalyzed in thre significant inc m. The highe could be expla or both biomas CO2, the use f CO2 were ob ddition on num garcane bagas perature and c ane bagasse. CH4 C 0.5 Moles he optimizatio perimental and omposition of b al., 2012) and maximization WG of glucose s and Guirard this work the CH4 or CO2 a e for isotherm ddition in iso seous product the sugarcan ass compositio ee different co crease in the H est concentrat ained by the l ss sources an e of CO2 as a bserved when mber of moles sse. Condition co-reactants a CO2 (a) 0 0.5 1 1.5 2 2.5 N um be r of m ol es 1 1 s of syngas (H n problems us d simulated d biomass sourc for sugarcane n models wer and cellulose dello, 2013) a ese models we as co-reactan mic (Gibbs en othermic syst s are present ne bagasse in on are fixed in onditions 15, 2 H2 production ions of CH4 w arge amounts nalyzed. The p a co-reactant this compoun s of main gase ns: temperatur addition on sy H2 Without co With 15 w With 25 w With 35 w With 15 w With 25 w With 35 w .5 2 H2+CO) sing the propo data can be fo ces was obtai e bagasse (Os re previously (Freitas and nd for the ox ere applied in nt in the SC ergy minimiza tems ted for the SC n Figure 1 (b) 1073.15 K, 2 5 and 35 wt% , mainly due to were observed s of CH4 used production of resulted in t nd was used a eous products re: 1073.15 K yngas producti CO C o-reactant t% of CH4 t% of CH4 t% of CH4 t% of CO2 t% of CO2 t% of CO2 2.5 With 25 Sugarcan With 25 Sugarcan Without sugarcan With 25 Nannoch With 25 Nannoch Without Nannoch osed approach ound in Freita ined in the lite sada et al., 20 validated wit Guirardello, 2 xidative reform n order to che CWG of micro ation) and ad CWG of micr ), in both cas 260 bar and 15 %. o the increase d in the system d in the feed s CO was favo the reduction as a co-reactan s in the SCWG K; pressure: 26 tion in the SC CH4 CO2 wt% of CO2 ne bagasse wt% of CH4 ne bagasse t co-reactant ne bagasse wt% of CO2 hloropsis wt% of CH4 hloropsis sp. t co-reactant hloropsis sp. hes, as as and erature 012). h both 2012a), ming of eck the oalgae iabatic oalgae ses the 5 wt%. e in the ms with stream. red for of H2 nt. G of (a) 60 bar; CWG of 2 (b) 171 The e additio elevat explai possib synga resulte prese that a molar 3.2. T In Tab reactio wt%). small i.e., th Table Nanno and b Co Wi 15 25 35 15 25 35 In Fig bioma more exothe system tempe Figure of Nan Figure simula the sy by ele H2 pro effect of temp on of co-react tion of syngas ined by the hig ble to verify th as produced i ed in a reduct nted a H2/CO aims H2 produc r ratio close to Thermodynam ble 1, the effe ons at consta In a General decrease in e he addition of 1. Effect of c ochloropsis sp iomass conce ondition ithout co-react 5 wt% CH4 5 wt% CH4 5 wt% CH4 5 wt% CO2 5 wt% CO2 5 wt% CO2 gure 3 the effe ass (15 wt%) a significant ex ermic behavio ms. Still in F erature resulte e 3. Effect of i nnochloropsis e 4 shows the ations the pre ystem were fix evations in the oduction. Sim 900 950 1000 1050 1100 1150 1200 1250 7 Fi na l t em pe ra tu re (K ) perature on s tants were fixe s production in gher reactivity hat the additio n this system tion in the num O ratio close to ction and the 2, for further mic effect of c ect of co-reac ant pressure ( l way, was po exothermic be CO2 resulted co-reactant ad p. and sugarca entration in the Nann tant 1044 1010 1003 1001 1058 1064 1069 ect of initial te and co-reacta xothermic beh or and CO2 a Figure 3, it is ed in the eleva initial tempera s sp. and suga e moles of sy essure, the com xed at 260 ba e initial tempe milar results w 00 750 8 syngas (H2+C ed at 25 wt% n all range and y of the system on of CH4 pre m presented a mber of moles o 2. In this wa addition of CO use in Fischer co-reactants a ctants addition 260 bar), initi ossible to veri ehavior of the in a small incr ddition on equ ane bagasse. e feed: 15 wt% Equilibriu nochloropsis 4.91 0.07 3.96 .65 8.39 4.88 9.72 emperature wa nt concentrati avior, within t addition result s possible to ation of equilib atures and co-r arcane bagass yngas produc mposition of b ar, 15 wt% and rature. The us were observed 800 850 9 Initial tem CO) production of CO2 or CH d for all cases ms in high tem esented a sign a high H2/CO s of syngas pr ay, the additio O2 proved to r-Tropsch pro addition in ad n was evaluate ial temperatur fy that for bot e system. The rease in exoth uilibrium tempe Conditions: in %. um temperat s sp. Suga 1151 1066 1055 1049 1162 1167 1172 as analyzed a on (25 wt%). the range exa ted in a smal o verify that i brium tempera -reactants add se. ced as functio biomass in the d 25 wt%, res se of CH4 as d when co-re 900 950 mperature (K) n is presente H4. The elevat s analyzed. Hig mperature cond nificant increa molar ratio. I oduced in the on of CH4 show be interesting cesses. diabatic syst ed on equilibr re (973.15 K) th substrates e addition of C hermic behavio eratures obse nitial tempera ures (K) arcane bagas .46 6.60 5.22 9.59 2.23 7.83 2.17 at constant pr The SCWG of amined. CH4 a l increase in in all range tures. dition on equili n of the initia e feed and the spectively. Th a co-reactant actants were 1000 1050 d in Figure 2 ion of tempera gher productio ditions. Analyz ase in syngas n other way t system but th wed to be inte to produce s ems rium temperat and composi the addition o CO2 showed a or of the syste erved in the S ture: 973.15 K sse ressure (260 b f sugarcane b addition result the exotherm analyzed the ibrium tempera al temperature e amount of c e syngas prod resulted in sig used in the 1100 Without c Nannoch With 25 w Nannoch With 25 w Nannoch Without c sugarcan With 25 w sugarcan With 25 w Sugarcan 2. In this figu ature resulted on of syngas c zing both figur s production, b the addition o he syngas pro eresting for sy syngas with a tures for the S ition of bioma of CH4 resulte an inverse be em. SCWG of micr K; Pressure: 2 bar), composi bagasse prese ted in a decre mic behavior o e elevation of ratures in the S e of reaction. co-reactant ad duction was fa gnificant incre SCWG of gl co-reactant hloropsis sp. wt% of CH4 hloropsis sp. wt% of CO2 hloropsis sp. co-reactant ne bagasse wt% of CH4 ne bagasse wt% of CO2 ne bagasse ure the d in the can be res it is but the of CO2 oduced ystems H2/CO SCWG ass (15 ed in a havior, roalgae 260 bar ition of ented a ease in of both f initial SCWG In the dded to avored ease in ucose, 172 cellulo 2013) remai The u prese Trops and G Guira Figure Nanno As the factor functio and b 15-35 Figure microa Analy the H2 with th Figure in red emph H2/CO 0 2 4 6 8 10 12 14 16 18 20 6 H 2/C O m ol ar r at io ose and micr ). With the ele ns with a high use of CO2 as nted a low H sch synthesis r Guirardello, 2 rdello, 2013). e 4. Effect of ochloropsis sp e H2/CO mola r was presente on of initial tem iomass compo 5 wt%. e 5. Effect of algae Nannoc yzing Figure 5 2/CO molar ra he addition of e 5 (b) for Sug ductions in the asized is that O molar ratios 773 873 973 1073 In iti al te m pe ra tu re (K ) 650 750 Ini (a) With CH4 addition With CO2 addition oalgae bioma evation of H2 p h H2/CO molar s a co-reactan H2/CO molar r reactions. Sim 2012a) and in f initial tempe p. and sugarca ar ratio was a ed in Figure 5 mperature of r osition (15 wt% f initial temper chloropsis sp. it is possible atio obtained in f CO2 with 25 garcane baga e H2/CO molar t the addition than when the 0 0.2 .15 .15 .15 .15 850 95 itial temperatu ass from C. v production the r ratio. nt resulted in ratio, which p milar results we n SCWG of erature and co ane bagasse. an important f 5. Figure 5 pr reaction; these %) the use of rature of reac and for (b) Su to verify that t n the product s and 35 wt% fo sse). The incr r ratio in all ra of CO2 even e highest CH4 0.4 0.6 Mo 0 1050 ure (K) Without co-r 15wt% of CH 25 wt% of C 35 wt% of C 15 wt% of C 25 wt% of C 35 wt% of C vulgaris and S e use of CH4 a decrease i provides that t ere observed biomass from o-reactant ad factor for furth resents the H e simulations CH4 and CO2 ction on H2/C ugarcane baga the addition of stream, but H for both substr rease in the c ange of compo n at the lowes 4 concentration 6 0.8 oles of syngas 1150 reactant H4 CH4 CH4 CO2 CO2 CO2 0 2 4 6 8 10 12 14 650 H 2/C O m ol ar r at io Spirulina sp. as a co-react n the total sy this syngas c in the SCWG m C. vulgaris ddition on syn her use of the H2/CO molar ra were perform 2 as co-reacta CO molar ratio asse. f both CH4 an 2/CO molar ra rates (Figure 5 oncentration o osition analyz st concentratio n (35 wt%) wa 1 1.2 (H2+CO) 0 750 Init With CH4 addition With CO2 addition (b) (Freitas and ant resulted in ngas producti could be used G of glucose an and Spirulin gas productio e syngas, a de atio obtained ed at constan nts were cons o observed in d CO2 resulte atios close to 2 5 (a) for Nann of co-reactant zed. Another in on analyzed ( as used as co- 1.4 1.6 With 25 wt% sugarcane b With 25 wt% Sugarcane b Without co- Sugarcane b With 25 wt% Nannochlor With 25 wt% Nannochlor Without co- Nannochlor 850 950 tial temperatur Guirardello, 2 n a product th ion, but this s d in further F nd cellulose (F na sp. (Freita on in the SC etailed study in the produc nt pressure (26 sidered in a ra the product ed in the reduc 2 was observe nochloropsis s in the feed re nteresting fac (15 wt%) had -reactant. 1.8 % of CO2 bagasse % of CH4 bagasse -reactant bagasse % of CO2 ropsis sp. % of CH4 ropsis sp. -reactant ropsis sp. 1050 ure (K) Without co-reacta 15 wt% of CH4 25 wt% of CH4 35 wt% of CH4 15 wt% of CO2 25 wt% of CO2 35 wt% of CO2 2012a, hat still syngas ischer- Freitas as and WG of of this ct as a 60 bar) ange of for (a) ction of ed only sp. and esulted ct to be d lower 1150 ant 173 The elevation of the initial temperature resulted in reductions on the H2/CO molar ratio observed in all conditions analyzed, molar ratio close to 2 was observed in systems with CO2 addition with 25 and 35 wt%. Modification of the biomass source showed a significant effect on the H2/CO molar ratio observed in the product stream, the sugarcane bagasse had lower H2/CO molar ratios in all conditions analyzed. This behavior can be visualized comparing Figures 5 (a) and (b). The use of co-reactants proved to be an effective way to improve syngas production in the SCWG of different biomass sources. The use of CO2 was more suitable for the production of syngas mainly because the syngas produced presented H2/CO molar ratio very close to 2, which is the ideal molar ratio for further use in Fischer-Tropsch synthesis reactions. The addition of CH4 presented a significant increase in the H2 production in the systems. This was the same behavior observed in the studies performed for isothermic systems. The addition of co-reactants did not modify significantly the thermal behavior of the studied systems under the conditions evaluated. 4. Conclusion The Gibbs energy minimization and entropy maximization methods, applied in the software GAMS and solved with the solver CONOPT proved to be quick and effective in the resolution of the proposed problems, with computational time inferior to 1 s in all cases analyzed. The calculated final temperatures were close to the initial temperature of the reaction in both systems, thus indicating low energy requirements for maintain these reactions in all conditions analyzed. The addition of CH4 showed to be interesting for systems that aims H2 production and the addition of CO2 (with 25 and 35 wt%) proved to be interesting to produce syngas with a H2/CO molar ratio close to 2, for further use in Fischer-Tropsch processes. The addition of co-reactants did not modify significantly the thermal behavior of the studied systems under the conditions evaluated. Acknowledgements The authors gratefully acknowledge the financial support from FAPESP – Fundação de Amparo à Pesquisa do Estado de São Paulo (Process 2011/20666-8) and CNPq – Conselho Nacional de Desenvolvimento Científico e Tecnológico, Brazil. References Ahmed I.I., Gupta A. K., 2012, Sugarcane bagasse gasification: Global reaction mechanism of syngas evolution. Applied Energy, 91, 75-81. Brunner G., 2009, Near critical and supercritical water. Part I. Hydrolytic and hydrothermal processes. Journal of Supercritical Fluids, 47, 373-381. Freitas A.C.D.; Guirardello R., 2013, Thermodynamic Analysis of Supercritical Water Gasification of Microalgae Biomass for Hydrogen and Syngas Production. Chemical Engineering Transactions, 32, 553-558, DOI: 10.3303/CET1332093 Freitas A.C.D., Guirardello R., 2012a, Supercritical Water Gasification of glucose and cellulose for hydrogen and syngas production. Chemical Engineering Transactions, 27 361-366, DOI: 103303/CET1227061 Freitas A.C.D., Guirardello R., 2012b, Oxidative reforming of methane for hydrogen and syngas production: Thermodynamic Equilibrium analysis. Journal of Natural Gas Chemistry, 21, 571-580. Guan Q., Savage P.E., Wei C., 2012, Gasification of alga Nannochloropsis sp. in supercritical water. Journal of Supercritical Fluids, 61, 139-145. Osada M., Yamaguchi A., Hiyoshi N., Sato O., Shirai, M., 2012, Gasification of sugarcane bagasse over supported ruthenium catalysts in supercritical water. Energy & Fuels, 26, 3179-3186. Pitzer K.S., Curl R.L., 1957, The volumetric and thermodynamic properties of fluids. III. Empirical equation of the second virial coeficient. J. Am. Chem. Soc., 79, 2369-2370. Ross A.B., Jones J.M., Kubacki M.L., Bridgeman T., 2008, Classification of macroalgae as fuel and its thermochemical behavior, Bioresource Technology, 99, 6494–6504 Tsonopoulos C., 1974, An empirical correlation of second virial coefficients. AIChE Journal, 20, 263-272. 174 Controfacciata.pdf iconBM 4-7 May 2014, Florence, Italy Guest Editors Volume 35 : Proceedings of the 16th Conference Process Integration, Modelling and Optimisation for Energy Saving and Pollution Reduction PRES’13, Rhodes, Greece, 29 September - 2 October 2013 Volume 36 : Proceedings of the 6th International Conference on Safety and Environment in Process & Power Industry, Bologna, Italy, 13-16 April, 2014 Disclaimer Official Organizer IndiceAutori.pdf AUTHOR Index Pagina vuota Controfacciata.pdf iconBM 4-7 May 2014, Florence, Italy Guest Editors 25.pdf Reduction of PM Emissions from Biomass Combustion Appliances: Evaluation of Efficiency of Electrostatic Precipitators Gabriele Migliavaccaa *, Carmen Morrealea, Francesca Hugonya, Ivan Tombolatob, Giordano Pessionb 442-444.pdf 3.4 Evaluation of the briquettes combustion 442-444.pdf 3.4 Evaluation of the briquettes combustion 25.pdf Reduction of PM Emissions from Biomass Combustion Appliances: Evaluation of Efficiency of Electrostatic Precipitators Gabriele Migliavaccaa *, Carmen Morrealea, Francesca Hugonya, Ivan Tombolatob, Giordano Pessionb