ARID ZONE JOURNAL OF ENGINEERING, TECHNOLOGY & ENVIRONMENT AZOJETE December 2019. Vol. 15(4):958-972 Published by the Faculty of Engineering, University of Maiduguri, Maiduguri, Nigeria. Print ISSN: 1596-2490, Electronic ISSN: 2545-5818 www.azojete.com.ng Corresponding author’s e-mail address: kabirumuazu@yahoo.co.uk 958 ORIGINAL RESEARCH ARTICLE PRODUCTION AND ECONOMICS EVALUATION OF PILOT SCALE ESSENTIAL OIL EXTRACT FROM EUCALYPTUS CITRIODORA LEAVES K. Mu’azu1*, G. Abubakar1, A. S. Akuso1, A. Mahmood2, I. G. Sadiq2 and B. Inuwa (1Department of Pilot Plants and Fabrication Technology, 2Department of Industrial and Environmental Pollution, National Research Institute for Chemical Technology, Zaria, Nigeria) * Corresponding author’s email address: kabirumuazu@yahoo.co.uk 1.0 Introduction Essential oils are volatile, natural base products, which are found in spices, aromatic and medicinal plants. The Extraction of essential oils is well known from old ages when pure essential oil and crude extract of essential oil bearing plants, herbs and grasses were in use for various medicinal and fragrances, flavors, preservatives and insect repellants purposes (Weiss, 1997; Panda, 2000). ARTICLE INFORMATION ABSTRACT In this study, essential oil was extracted from eucalyptus citriodora leaves plant species (lemon-scented gum) in a pilot plant using steam distillation technology. The extraction pattern of the oil was monitored over time and economic analysis of the production was carried out. Five batches were carried out in a day and the results revealed that the daily production of the oil was 0.579 liters in a loading capacity of 100kg of leaves. It was also observed that the total production cycle per batch was 1.96 hours out of which 80 minutes were the actual extraction time with lag period of 37 minutes. The results further revealed that 66.7% of the oil was extracted in 40 minutes while 95.6% in 80 minutes. Liquefied petroleum gas (LPG) was used as source of energy with daily consumption of 7.5 kg at a cost of N2,400.00K. The economic analysis on annual basis revealed that the operating cost was N1,742,400.00K. The production output of the oil was estimated at 138.96 litres with expected selling price of N4,863,600.00K at the rate of N35,000.00K per litre and expected profit after tax of N2,115,871.00K. From this economic analysis carried out based on the practical data generated in the pilot plant, this project is highly profitable and is strongly recommended to potential investors and entrepreneurs. This will help in providing jobs for our teaming unemployed youths mostly in rural areas where these raw materials are in abundant thereby increasing nation’s foreign earning due to its export potential. © 2019 Faculty of Engineering, University of Maiduguri, Nigeria. All rights reserved. Submitted 15 November, 2018 Revised 15 June, 2019 Accepted 20 June, 2019 Keywords: Eucalyptus citriodora leaves essential oil steam distillation economic analysis and oil yield . mailto:kabirumuazu@yahoo.co.uk http://www.azojete.com.ng Arid Zone Journal of Engineering, Technology and Environment, December, 2019; Vol. 15(4) 958-972. ISSN 1596-2490; e-ISSN 2545-5818; www.azojete.com.ng Corresponding author’s e-mail address: kabirumuazu@yahoo.co.uk 959 Eucalyptus plant is mainly grown in tropical and sub-tropical regions because of its resistance to many pest and adaptability to various climatic conditions. These include South Africa, China, Congo Republic, Angola, India and West Africa. The plant has up to 700 species and can grow as high as 40 m tall in an altitude of 600m. The principal component of the essential oil extracted from eucalyptus citriodora leave is cineola which is up to 70 - 80%. The oil is mainly used in medicinal, industrial and perfumery applications. The yield of essential oil is naturally constrained (usually less than 2%) but with high market value. (UNIDO, 1983). Many research works have been published on extraction of essential oil from eucalyptus citriodora leave mostly at laboratory stage without economics of its production (Seid et al., 2014; Deepak et al., 2013; Manika, et al., 2012). Mu’azu et al. (2009) reported economics of essential oil production using eucalyptus citriodora leaves at pilot plant. However, data used in the study were not optimized and kerosene was used as fuel. Scanty information is available in the literature regarding the detailed economic study on the production of essential oil from eucalyptus citriodora leaves at pilot scale level using steam distillation technology and liquefied petroleum gas (LPG) as source of energy. It must be noted that energy cost accounts for about 70% of the production cost. Against this background, a study was therefore planned from practical approach to determine the actual daily production of the essential oil, production costs and profit margin in a pilot plant. This information can serve as an important resource in attracting investors to the essential oil industry and exploring its commercial utilization. 2. Materials and Methods The block diagram and flow sheet for the extraction process of essential oil from eucalyptus leaves using steam distillation method were developed and shown in Figures 1 and 2 respectively. Figure 1: Block diagram for the steam extraction of essential oil from Eucalyptus leaves Cooling water in Steam PRE-TREATMENT UNIT ESSENTIAL OIL EXTRACTOR CONDENSER DRYING UNIT OIL SEPARATOR Spent leaves Fresh Leave Cooling water outSteam and essential oil vapor Warm water Essential Dried Essential Foreign materials lealealeaves Eucalyptus leave file:///C:/Users/user/Downloads/azojete143/www.azojete.com.ng Mu’azu et al: Production and economics evaluation of pilot scale essential oil extract from eucalyptus citriodora leaves. AZOJETE, 15(4):958-972. ISSN 1596-2490; e-ISSN 2545-5818, www.azojete.com.ng Corresponding author’s e-mail address: kabirumuazu@yahoo.co.uk 960 Figure 2: Flow sheet for the steam extraction of essential oil from Eucalyptus leaves Key: A-Boiler B-Extractor C-Storage water tank D-Condenser E-Storage water tank F-Oil separator G-Water pump 2.1 Material Procurement and Preparation Fresh Eucalyptus leaves shown in Figure 3 were obtained from National Research Institute for Chemical Technology (NARICT) plantation in Zaria, Nigeria. Prior to commencement of the extraction process the unwanted materials found in the leaves were removed and 20kg of the leaves were weighed for a batch operation. Figure 3: Eucalyptus citriodora leaves E http://www.azojete.com.ng mailto:kabirumuazu@yahoo.co.uk Arid Zone Journal of Engineering, Technology and Environment, December, 2019; Vol. 15(4) 958-972. ISSN 1596-2490; e-ISSN 2545-5818; www.azojete.com.ng Corresponding author’s e-mail address: kabirumuazu@yahoo.co.uk 961 2.2 Description of the Essential Oil Extraction Plant The extraction of essential oil was done using water as solvent in the form of steam in a steam distillation pilot plant. The pilot plant consists mainly of oil extractor, steam boiler, condenser, gas-fired burner and oil separator as shown in Figure 4. Figure 4: Steam distillation pilot plant for extracting essential oil from eucalyptus leaves The oil extractor and condenser were fabricated using grade 304 stainless steel while the oil separator was transparent glass. The boiler section is located at the bottom of the oil extraction chamber and separated by a stainless steel weir mesh. The gas-fired burner was connected to a 12.5 kg gas cylinder with a rubber hose and placed directly under the oil extractor. The connections were adequately checked to avoid gas leakages. The cooling water at 25°C from the overhead tank was allowed to run into the condenser at the rate of 1.67x10-3 m3/min and discharged at 40 °C. This was done to aid easy condensation of the steam and oil mixture vapour at 100 °C to liquid. A detail of these equipment specifications is shown in Table 1. Table 1: Summary of process unit specifications Process unit Specification Extractor Material of construction Stainless steel Height 1.65 m Diameter 0.45 m Thickness 0.003 m Boiler Capacity 0.0075 m3/hour KEY A=Essential oil extractor B=Boiler C=Condenser D=Cooling water tank E=Oil collector F=Steam and oil line G=Cooling water line file:///C:/Users/user/Downloads/azojete143/www.azojete.com.ng Mu’azu et al: Production and economics evaluation of pilot scale essential oil extract from eucalyptus citriodora leaves. AZOJETE, 15(4):958-972. ISSN 1596-2490; e-ISSN 2545-5818, www.azojete.com.ng Corresponding author’s e-mail address: kabirumuazu@yahoo.co.uk 962 Condenser Type of condenser shell and tube Material of construction of shell mild steel Material of construction of tube stainless steel Number of passes in the tube 2 Number of pass in the shell 1 Tube length 1.2 m Tube outside diameter 0.02 m Tube inside diameter 0.016 m Number of tubes 16 Number of tubes per pass 8 Shell internal diameter 0.385 m Number of baffles 3 Baffles spacing 0.3 m Baffles cut 15% Baffle pitch Square Tube side fluid Steam and oil Shell side fluid Cooling water Oil separator Capacity 0.0005 m3 Shape Conical Flow rate 0.00025 m3/min 2.3 Methods Twenty five (25) litres of water and 20kg (W1) of fresh eucalyptus leaves were charged into the essential oil extractor (A) shown in Figure 4. The gas line was opened and the burner was ignited and time of ignition was recorded. The burner fuel- to- air ratio was adjusted until blue flame was obtained implying steady energy supply. After 24 minutes of burner ignition (Induction period), steam and oil mixture began to drop in the oil separator (E) at 40°C as condensate. The oil was then separated from the warm water using separating flask and measured in a cylinder after every 10 minutes for a period of 100 minutes. The cumulative oil collected was dried using 150g of anhydrous Sodium Sulphate (Na2SO4) and allowed to stand for overnight (12 hours) followed by filtration to remove moisture and suspended impurities associated with the oil as shown in Figure 5. The same procedures were repeated for subsequent batches with addition of 10 litres of the warm water collected into the boiler as make-up water to maintain minimum of 20 litres at any time. In each case the weight of the dried oil was recorded (W2) and oil yield was calculated using Equation (1). Oil Yield = W2 W1 x 100 (1) http://www.azojete.com.ng mailto:kabirumuazu@yahoo.co.uk Arid Zone Journal of Engineering, Technology and Environment, December, 2019; Vol. 15(4) 958-972. ISSN 1596-2490; e-ISSN 2545-5818; www.azojete.com.ng Corresponding author’s e-mail address: kabirumuazu@yahoo.co.uk 963 Figure 5: Essential oil extracted 2.3.1 Material Balance The material balance was carried out on the process units based on the plant throughput of 115.84ml (1.1584 x 10-1 kg) of essential oil per batch, leaves input of 20 kg, extraction time of 100 minutes, water requirement of 15 liters (15kg) and steam production of 8.894 kg. Thus, for a steady state batch process without chemical reaction, the material balance is given by Equation (2) and was applied to all the process units starting with oil extractor as shown in Figure 6. Figure 6: Material balance over oil extractor In the condenser unit steam oil mixture passes through the tube side while cooling water in the shell and the material balance is presented in Figure 7. Figure 7: Material balance over oil condenser Mixture of hot water and essential oil from the condenser were fed into the oil separator and the material balance is presented in Figure 8 Oil Extractor Steam (S), 1.482 x 10-3kg/s Oil (O), 1.930 x 10-5kg/s Unused water (UW), 1.018 x 10-3kg/s Leaves (L), 3.333 x 10-3kg/s Water (W), 2.500 x 10-3kg/s Spent leaves (SL), 3.310 x 10-3kg/s Oil (O), 1.930 x 10-5kg/s Oil (O), 1.930 x 10-5kg/s Condenser Hot water (HW), 1.482 x 10-3kg/s Cooling water (CW1), 2.783 x 10-4kg/s Steam (S), 1.482x 10-3kg/s Cooling water (CW2), 2.783 x 10-4kg/s file:///C:/Users/user/Downloads/azojete143/www.azojete.com.ng Mu’azu et al: Production and economics evaluation of pilot scale essential oil extract from eucalyptus citriodora leaves. AZOJETE, 15(4):958-972. ISSN 1596-2490; e-ISSN 2545-5818, www.azojete.com.ng Corresponding author’s e-mail address: kabirumuazu@yahoo.co.uk 964 Figure 8: Material balance over oil separator The material balance on the drying unit is presented in Figure 9. Figure 9: Material balance over drying unit 2.4 Energy Utilization The quantity of gas (G) utilized in kg for every batch operation was calculated by taking the respective difference between the initial weight of gas cylinder (W3) and its final weight (W4) after each production cycle as given in Equation (3). (3) The energy utilization, Q (in MJ) per batch was thereafter obtained from Equation (4). where G is the quantity of gas consumed (kg) and CV is the calorific value of gas in MJ/kg and has the value of 46.1 MJ/kg for LPG. 2.4.1 Energy Balance over Oil Extractor In Figure 6, for a batch process without chemical reaction, the energy balance is given as Qsupplied = Qwater + Qevap +Qoil + Qleave + Qtank + Qlost (5) Qsupplied = 11,525J/s as given in Equation (4). Heat gained by water in the boiler (Qwater) = MwCwΔTw, Mw = 2.500 x 10-3 kg/s, Cw = 4.200 x 103 J/kg°C, ΔTw = 75°C, implying that Qwater= 787.5 J/s. Heat needed to evaporate water in the boiler (Qevap) = MsL, Ms = 1.482 x 10-3kg/s, L = 2.260 x 106 J/kg, implying that Qevap = 3350.1 J/s. Heat gained by oil in the leaves (Qoil) = MoilCoilΔToil, Moil = 1.930 x 10-5kg/s, Coil = 2.6 x 10-3 J/kg°C, ΔToil = 75°C, implying that Qoil = 3.765 x 10-6 J/s. Heat gained by the leaves (Qleave)=MLCLΔTL, ML = 3.310 x 10-3 kg/s, Oil Separator Hot water (HW2), 1.475 x 10-3kg/s Oil (O2), 2.671x 10-5kg/s Hot water (HW1), 1.482 x 10-3kg/s Oil (O1), 1.930 x 10-5kg/s Drying Unit Drying agent (D2), 2.50 x 10-5kg/s Oil (O2), 1.930 x 10-5kg/s Drying agent (D), 2.50x 10-5kg/s Oil (O1), 2.671 x 10-5kg/s Water (W), 7.410 x 10-6kg/s http://www.azojete.com.ng mailto:kabirumuazu@yahoo.co.uk Arid Zone Journal of Engineering, Technology and Environment, December, 2019; Vol. 15(4) 958-972. ISSN 1596-2490; e-ISSN 2545-5818; www.azojete.com.ng Corresponding author’s e-mail address: kabirumuazu@yahoo.co.uk 965 CL= 0.5 x Cwood = 9.414 x 102 J/kg°C, ΔTL = 75°C, implying that QL = 233.987 J/s. Heat lost to the surrounding (Qlost) = 20% of Qsupplied = 2,305 J/s From Equation (5), heat gained by oil extractor (Qtank) = Qsupplied - Qwater - Qevap - Qoil - Qleave - Qlost, implying that Qtank = 4,848.41 J/s 2.4.2 Energy Balance over Condenser In the condenser unit shown in Figure 7 and assuming steady state energy supply, the heat released by the steam oil mixture equals to heat absorbed by the cooling water. Thus, Qsteam oil mixture = Qcooling water. Qsteam oil mixture = 3,350.1 J/s= Mcw x Ccw x (T2 –T1), where Mw =mass flow rate of cooling water = 2.783 x 10-4 kg/s, Ccw = specific heat capacity of water = 4,200 kJ/kg°C, T1= inlet water temperature = 25°C. Solving for T2 = 28°C. 2.4.3 Energy Balance over Separator The energy balance in the oil separation unit shown in Figure 8 was carried out based on the fact that the separation of water oil mixture was based on density difference and occurred at room temperature (25°C) implying that there was no temperature gradient. Thus, Mw1 Hw1 + Mo1 Ho1 = Mw2 Hw2 +Mo2 Ho2 and Mw1= Mw2=1.482 x 10-3 kg/s, Hw1=Hw2= 419.1 kJ/kg (enthalpy of water at 25°C), Mo1=Mo2 = 1.93 x 10-5 kg/s and Ho1 = Ho2 = 0.65 kJ/kg. 2.5 Determination of Extraction Time The extraction time was determined using stop clock by recording the time for loading the leaves and sealing the tank cover (T1), time the first drop of steam oil mixture was collected (T2) and the time between first drop of steam oil mixture and its last drop (T3) and time the spent leaves were off-loaded (T4). 2.6 Determination of Steam Requirement The steam needed to extract the essential oil from unit kilogram of the leaves was determined from the cumulative condensate collected at the end of batch operation. The ratio of steam collected to the quantity of leaves loaded gives steam to leave ratio. 2.7 Economic Analysis The analytical tools employed for calculating the economic indices of the plant such as total investment cost, direct and indirect production costs, annual operating cost, profit after tax, return on investment, break-even point and payback period were obtained from a related works (Mu’azu et al., 2009 and Galidama, 2004). 3. Results and Discussion This section discussed both the material and energy balance carried out in the plant. Similarly, total extraction time per batch including loading and off- loading of leaves, induction period and actual extraction time were also presented and discussed. These results will help an investor to know the number of batches to run on daily basis, time for stoppage of the extraction, actual file:///C:/Users/user/Downloads/azojete143/www.azojete.com.ng Mu’azu et al: Production and economics evaluation of pilot scale essential oil extract from eucalyptus citriodora leaves. AZOJETE, 15(4):958-972. ISSN 1596-2490; e-ISSN 2545-5818, www.azojete.com.ng Corresponding author’s e-mail address: kabirumuazu@yahoo.co.uk 966 steam and energy requirements in a batch operation and economics for the production has also been discussed. 3.1 Material Balance The summary of material balance carried out in the plant is presented in Table 2. It is evident that in every 3.333 x 10-3 kg/s of eucalyptus leaves charged into the extractor, the output of essential oil was 1.980 x 10-5 kg/s and required 1.482 x 10-3 kg/s of steam. This implies that steam to leaves mass ratio per second was 1.482 x 10-3 : 3.33 x 10-3 or 1 : 25 and oil to leaves mass ratio per second was 1.980 x 10-5 : 3.333 x 10-3 or 1 : 1.68 Table 2: Summary of material balance for the process units Oil extractor Material Input, kg/s Output, kg/s Eucalyptus Leaves 3.333 x 10-3 3.333 x 10-3 Water 2.500 x 10-3 3.333 x 10-3 Steam 1.482 x 10-3 Essential oil 1.930x 10-5 Spent Leaves 3.310 x 10-3 Unused water 1.018 x 10-3 Total 5.833 x 10-3 5.830 x 10-3 Condenser Steam 1.482 x 10-3 Cooling water 2.783 x 10-4 Essential oil 1.930 x 10-5 1.930 x 10-5 Hot water 1.482 x 10-3 Warm water 2.783 x 10-4 Total 1.780 x 10-3 1.780 x 10-3 Oil separator Hot water 1.482 x 10-3 1.475 x 10-3 Essential oil 1.930 x 10-5 2.671 x 10-5 Total 1.501 x 10-3 1.501 x 10-3 Drying unit Essential oil 2.671 x 10-5 1.930 x 10-5 Sodium sulphate 2.500 x 10-5 2.500 x 10-5 Water 7.41 x 10-6 Total 5.17 x 10-5 5.17 x 10-5 3.2 Energy Balance The summary of energy balance carried out in the plant is presented in Table 3. At a steady state, the energy supply by the steam (11,525 J/s) equals to energy gained by the leaves, oil, water, extraction tank and lost to surrounding and due evaporation. However, the energy gained by the oil (3.765 x 10-6 J/s) was negligible compared to water (787 J/s) and leaves (233.99 http://www.azojete.com.ng mailto:kabirumuazu@yahoo.co.uk Arid Zone Journal of Engineering, Technology and Environment, December, 2019; Vol. 15(4) 958-972. ISSN 1596-2490; e-ISSN 2545-5818; www.azojete.com.ng Corresponding author’s e-mail address: kabirumuazu@yahoo.co.uk 967 J/s). In the oil separation unit, there was not temperature gradient (25°C) and therefore the energy remained constant. Table 3: Summary of energy balance for the process units Oil extractor Item Input, J/s Output, J/s Energy supplied 11,525.00 Heat gained by water 787.50 Heat of evaporation 3350.10 Heat gained by oil 3.765 x 10-6 Heat gained by leaves 233.99 Heat lost to surrounding 2305.00 Heat gained by extraction tank 4848.41 Total 11,525.00 11,525.00 Condenser Heat released by steam 3350.10 Heat released by oil 3.765 x 10-6 Heat gained by cooling water 3350.10 Total 3350.10 3350.10 Oil separator Warm water 621.00 621.00 Essential oil 1.25 1.25 Total 622.25 622.25 3.3 Extraction Time The total extraction time per batch consists of time for loading of eucalyptus leaves into the oil extractor, induction time, actual extraction time and time for off-loading the spent leaves as shown in Table 4. Table 4: Sequential production time for each activity in a production cycle Batch Loading of fresh leave, T1 (minutes) Induction period, T2 (minutes) Extraction time, T3 (minutes) Off-loading of spent leave, T4 (minutes) 1 5 32 100 10 2 4 20 100 8 3 5 28 100 9 4 5 25 100 9 5 4 15 100 10 Average 4.6 24 100 9.2 It can be seen from Table 4 that the average time required for loading was 4.6 minutes and 9.2 minutes for off-loading the spent leave and these times were considered as the lag time in the production cycle. The induction period is the time between ignition of the burner and the first file:///C:/Users/user/Downloads/azojete143/www.azojete.com.ng Mu’azu et al: Production and economics evaluation of pilot scale essential oil extract from eucalyptus citriodora leaves. AZOJETE, 15(4):958-972. ISSN 1596-2490; e-ISSN 2545-5818, www.azojete.com.ng Corresponding author’s e-mail address: kabirumuazu@yahoo.co.uk 968 drop of the steam plus oil mixture. This period is generally dependent on the energy supply, volume of the water in the boiler and loading density of the leave. In this study, the period was higher for the 1st batch (32 minutes) compared to other four batches and was due to the addition of both sensible heat and latent heat to the fresh water in the boiler whereas in the other four batches only latent heat was added. However, the average induction period was 24 minutes and is in agreement with the values obtained by Okonkwo et al (2010) and Mu’azu et al (2012). Although, the average extraction time was 100 minutes, it was observed that up to 67% of the oil was collected between 0- 40 minutes and 95.90% was collected within 80 minutes. This implies that extraction beyond 80 minutes is uneconomical relative to energy input which was considered as the major production cost. Therefore, the effective production time per batch is the summation of time of loading, induction, extraction and off-loading and was found to be 117.8 minutes (1.96 hours) 3.4 Effect of Extraction Time on Oil Yield The effect of extraction time on yield of the essential oil extracted is presented in Figure 10. The oil yield increases with increase in extraction time for all the batches until it reached 30 minutes for the 2nd batch and 20 minutes for the other batches before declining. The difference in the extraction pattern between 2nd batch and other batches could be due to loading pattern of the leaves. Figure 10: Extraction pattern of essential oil as a function of time It was also observed that about 67.7% of the oil was extracted between 0-40 minutes while 95.90% was extracted in 80 minutes for all the batches (Figure 11). The cumulative volume of the oil extracted ranged from 99.9-131.2 ml with an average yield of 115.84 ml (0.1158 litres) per batch. This implies that for 5 batches operation in a day the average oil yield was 579.2 ml (0.579 litres). http://www.azojete.com.ng mailto:kabirumuazu@yahoo.co.uk Arid Zone Journal of Engineering, Technology and Environment, December, 2019; Vol. 15(4) 958-972. ISSN 1596-2490; e-ISSN 2545-5818; www.azojete.com.ng Corresponding author’s e-mail address: kabirumuazu@yahoo.co.uk 969 Figure 11: Cumulative volume of essential oil as a function of time 3.5 Steam Requirement for Extraction The quantity of steam needed to rupture the leaves for the oil to be released from the cell matrix and transported to the condenser is presented in Table 5. Table 5: Cumulative condensate collected in each batch Time (Minutes) Batch 1 (ml) Batch 2 (ml) Batch 3 (ml) Batch 4 (ml) Batch 5 (ml) 10 521.7 425 550 510 1200 20 1540.7 1565 1490 1290 2880 30 2450.7 2965 2430 1910 4440 40 3540.7 4015 3330 2530 5760 50 4510.7 5135 4220 3190 6970 60 5460.7 6275 5100 3830 8190 70 6450.7 7335 5920 4620 9350 80 7435.7 8355 6710 5120 10470 90 8325.7 9415 7440 5560 11710 100 8625.7 9725 7760 5920 12440 It is evident in Table 5 that the cumulative volume of water required for daily operation of 5 batches was 44470.7 ml (44.47 litres) with average batch consumption of 8894.14 ml (8.894 litres). However, 15 litres of water is recommended per batch to compensate for losses during production. The steam to oil volumetric ratio per batch was 77:1 (8894.14 ml/115.84 ml) and steam to leave ratio was 445:1 (8894.14 ml/20 kg). 3.6 Energy Requirement Energy consumption plays a significant role in the extraction of essential oil from aromatic plant using steam distillation method. As seen in Table 6 the first batch consumed more energy as a result of addition of both sensible and latent heats when compared with the other batches file:///C:/Users/user/Downloads/azojete143/www.azojete.com.ng Mu’azu et al: Production and economics evaluation of pilot scale essential oil extract from eucalyptus citriodora leaves. AZOJETE, 15(4):958-972. ISSN 1596-2490; e-ISSN 2545-5818, www.azojete.com.ng Corresponding author’s e-mail address: kabirumuazu@yahoo.co.uk 970 where only latent heat was applied. It was observed that the average gas utilization per batch was 1.5 kg with corresponding energy input of 69.15MJ. Table 6: Energy utilization for each batch operation Batch Quantity of gas consumed (kg) Energy utilized (MJ) 1 1.8 82.98 2 1.4 64.54 3 1.4 64.54 4 1.4 64.54 5 1.5 69.14 3.7 Economic Analysis Table 7 presents economic analysis of the plant based on daily throughput of 0.579 litres of essential oil per batch and 20 working days in a month. The estimated cost of the plant is N3,500,000.00K with an assumed lifespan of 35 years. The profit after tax (PAT) of N2,115,871.00 obtained in this study was higher than N981,600.00 and N1,818,806.00 obtained in a separate studies using kerosene as fuel (Mu’azu, et al., 2009; Galadima, 2004). The difference in the net profit is mainly due to type of fuel used and cost of raw materials. Table 7: Economic analysis for production of eucalyptus essential oil on annual basis S/N Item Equation Value Amount (N) Total(N) 1a Fixed capital cost (Fc) 3,500,000.00 1b Land & Non depreciable costs (Lc) 50,000.00 1c Capital for test-run (Wc) 20,000.00 1d Total Investment Cost (Tc) Fc + Lc +Wc 3,570,000.0 2a Raw materials (Rm) 240,000.00 2b Utilities (U) 605,400.00 3a Maintenance (Mc), 1% of Fc 35,000.00 3b Labour cost (Lc) 720,000.00 3c Plant overhead (PO), 10% of Fc 72,000.00 3d Local taxes (Lt), 1% of Fc 35,000.00 3e Insurance (I), 1% of Fc 35,000.00 3f Direct Production Cost (DPC) Mc+Lc+PO+ Lt+I 897,000.00 4 Sales expenses (4% of DPC) 35,880.00 5 General Overhead (4% of DPC) 35,800.00 6 Research & Development (8% of DPC) 71,760.00 7 Annual Operating Cost (AOC) Rm+U+DPC 1,742,400.0 8a Annual production138.96 liters http://www.azojete.com.ng mailto:kabirumuazu@yahoo.co.uk Arid Zone Journal of Engineering, Technology and Environment, December, 2019; Vol. 15(4) 958-972. ISSN 1596-2490; e-ISSN 2545-5818; www.azojete.com.ng Corresponding author’s e-mail address: kabirumuazu@yahoo.co.uk 971 8b Annual selling price (ASP) @ N35,000/L 4,863,600.00 8c Operating profit (OP) ASP-AOC 3,121,200.0 8d Lifespan of the plant (Ls), years 35 8e Salvage value (Sv) 0.35 x Tc 124,950.00 8f Depreciation (D) (Tc-Sv)/Ls 98,430.00 8g Profit Before Tax (PBT) OP-D 3,022,700.00 8h Tax (T), 30% 0.3x PBT 906,831.00 8i Profit After Tax (PAT) PBT-T 2,115,871.00 8j Return on Investment (ROI),% (PAT/Tc) x100 59.27 8h Profit Margin (PM),% (PAT/ASP) x 100 43.50 9a Equity (E), @20% 0.2xTc 714,000.00 9b Return on Equity (ROE),% (PAT/E)x100 296.34 9c Annual Cash Flow (ACF) PAT+D 2,214,301.0 9d Break Even Point (BEP) [Fc/(ASP- OC)] 1.12 9e Pay Back Period (PBP) Tc/ACF 1.61 years 4. Conclusion The study revealed an average oil production of 0.579 litres in a day within a production cycle of 8.33 hours. The study further revealed that with an initial investment of N3,570,000:00K, the expected annual profit after tax was N2,115,871:00K and project payback period of 1.61 years. These promising economic indices suggest that extraction of essential oil using LPG has higher returns than kerosene and is strongly recommended to any potential investor in the sector. Acknowledgements The authors express their sincere appreciation to the Director-General/CEO of National Research Institute for Chemical Technology (NARICT), Zaria for his moral and financial supports towards this project. The friendly corporation and support by members of staff of Pilot Plants & Fabrication Technology, NARICT, Zaria is also highly appreciated. References Deepak, G., Mumtaj, S. and Prashant, S. 2013. Microwave-Assisted Extraction of Eucalyptus Citriodora Oil and Comparison with Conventional Hydro Distillation. Middle-East Journal of Scientific Research, 16 (5): 702-705. Galadima, MS. 2004. Design and fabrication of a pilot plant for steam distillation of essential oil. M.Sc. thesis, Department of Chemical Engineering, Ahmadu Bello University, Zaria, Nigeria,87-92. Manika, N., Priyanka, M., Narendra, K., Chanotiya, CS. and Bagchi, GD. 2012. Effect of season on yield and composition of the essential oil of Eucalyptus citriodora Hook. leaf grown in sub- file:///C:/Users/user/Downloads/azojete143/www.azojete.com.ng Mu’azu et al: Production and economics evaluation of pilot scale essential oil extract from eucalyptus citriodora leaves. AZOJETE, 15(4):958-972. ISSN 1596-2490; e-ISSN 2545-5818, www.azojete.com.ng Corresponding author’s e-mail address: kabirumuazu@yahoo.co.uk 972 tropical conditions of North India. Journal of Medicinal Plants Research, 6(14): 2875-2879. Available online at http://www.academicjournals.org/JMPR Mu’azu, K., Okonkwo, EM. and Abdullahi, M. 2009. Economic analysis of production of essential oil using steam distillation technology. 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Weiss, EA. 1997. Essential Oil Crops, CAB International, USA, 65-67 http://www.ajol.info/browse-journals http://www.azojete.com.ng mailto:kabirumuazu@yahoo.co.uk