Biodiesel production from waste cooking oil: An efficient technique to convert waste into biodiesel

Sustainable Cities and Society 41 (2018) 220–226

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Biodiesel production from waste cooking oil: An efficient technique to convert waste into biodiesel

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Sahara, Sana Sadafb, , Javed Iqbala,c, Inam Ullahd, Haq Nawaz Bhattia, Shazia Nourene, ⁎ Habib-ur-Rehmanf, Jan Nisarg, Munawar Iqbalh, a

Department of Chemistry, University of Agriculture, Faisalabad, Pakistan Bio-Analytical Chemistry Laboratory, Punjab Bio-Energy Institute, University of Agriculture, Faisalabad, Pakistan c Energy Physics Laboratory, Punjab Bio-Energy Institute, University of Agriculture, Faisalabad, Pakistan d Department of Chemistry, University of Sargodha, Lyallpur Campus, Faisalabad, Pakistan e Department of Chemistry, Government College Women University, Sialkot, Pakistan f Insect Biofuel Laboratory, Punjab Bio-Energy Institute, University of Agriculture, Faisalabad, Pakistan g National Centre of Excellence in Physical Chemistry, University of Peshawar, Peshawar, 25120, Pakistan h Department of Chemistry, The University of Lahore, Lahore, Pakistan b

A R T I C LE I N FO

A B S T R A C T

Keywords: Waste cooking oil Biodiesel Pretreatment Transesterification GC analysis

Biodiesel production from waste oils is an attractive option to produce biodiesel economically, but high free fatty acids (FFA) in waste oils are a serious bottleneck for the process of transesterification. Present investigation deals with the utilization of waste cooking oil (WCO) for the production of biodiesel. The acid value of WCO was 5.5 mg KOH/g which indicated high FFA content. The WCO was subjected to esterification using different acid catalysts (HCl, H2SO4 and H3PO4) and H2SO4 catalyzed reaction was found to be the most efficient since the FFA reduced up to 88.8% at 60 °C with 1:2.5 methanol to oil molar ratio. Transesterification was done in the presence of alkali catalyst (KOH) and Fatty acid methyl ester (FAME) yield was 94% in the presence of 1% catalyst at 50 °C. The biodiesel was characterized based on acid value, saponification value, iodine value, cetane number, specific gravity, viscosity, cloud point, pour point and calorific value. The Gas Chromatography (GC) analysis of synthesized biodiesel was also performed. Base on ASTM standards, alkali catalyzed transesterification was an efficient method to produce biodiesel form WCO. Results revealed that the waste cooking oils can be converted into biodiesel as an energy source along with environmental pollution reduction.

1. Introduction The energy demand is continuously increasing due to fast industrialization and metropolitan growth. The major energy resources are petroleum, coal and natural gas and due the non-renewable nature, these energy sources are decreasing day by day (Arshad et al., 2018). Recently, the petroleum prices have been setting record high in the history due to heavy dependence on petroleum as a major source of fuel for transportation and electricity generation. On the other hand, the exploitation of these conventional energy resources is also a reason of global warming, which needs to be tackled by adopting alternative energy sources (Canesin & Oliveria, 2014). Both energy and environmental deterioration are serious crisis, which could possibly be reduced by adopting alternative energy sources such as biofuels generation from renewable sources as well as the adoption of sustainable and environmental friendly methods for the generation of biodiesel (Asri & Sari,

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2015; Asri, Sari, Poedjojono, & Suprapto, 2015; Haigh, Abidin, Saha, & Vladisavljević, 2012; Hiwot, 2017; Noiroj, Intarapong, Luengnaruemitchai, & Jai-In, 2009; Saifuddin, Raziah, & Farah, 2009; Omar, Nordin, Mohamed, & Amin, 2009; Wang, Ou, Liu, Xue, & Tang, 2006). Biofuels are very attractive option to overcome the energy crisis since waste feedstock’s are available freely for the production of biofuels (biodiesel, bioethanol, biogas etc) by different chemical and biological conversion technologies (Che, Sarantopoulos, Tsoutsos, & Gekas, 2012; Wen, Jiang, & Zhang, 2009). The biofuel production is increasing globally, which will grow in coming years due to continuous dwindling of fossil fuel reserves (Yusuf, Kamarudin, & Yaakub, 2011). Among different types of biofuels, biodiesel is getting more attraction in view of properties and chemical nature, which can be used as blend with diesel fuel (Nisar et al., 2018). To utilize the biodiesel as a fuel, no engine modification is required for (Boon, Van Dijk, De Munck, & Van

Corresponding authors. E-mail addresses: [email protected] (S. Sadaf), [email protected], [email protected] (M. Iqbal).

https://doi.org/10.1016/j.scs.2018.05.037 Received 18 December 2017; Received in revised form 22 May 2018; Accepted 22 May 2018

Available online 23 May 2018 2210-6707/ © 2018 Elsevier Ltd. All rights reserved.

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yield of 96.1% was achieved. Nisar et al. (2018) used Brassiceae family plants oil for biodiesel production using chemical refining followed by direct homogeneous alkali catalyzed transesterification and methyl esters from Brassiceae family plants are acceptable biodiesel. Waste cooking oil (WCO) is easily available from restaurants, cafeterias and household kitchens. Present research was focused on the conversion of WCO into biodiesel. The high level FFAs in waste cooking oils result in accelerating some undesirable side reactions during biodiesel production. Therefore, WCO was pretreated first with mineral acids for reduction of FFAs and then subjected to transesterification in the presence of base as a catalyst. The synthesized biodiesel was characterized and compared with fuel standards.

Den Brink, 2011) and in contrast to conventional petroleum diesel, the biodiesel is a clean, safe and non-hazardous due to its biodegradability, renewable and carbon neutral nature (Dong, Zhu, & Dai, 2012; Roy, Wang, & Alawi, 2014). Chemically, biodiesel is fatty acid methyl esters (FAME), which can be synthesized by chemical reaction between alcohol and oil in presence of a suitable catalyst, and feedstock’s like energy cops, animal fats, kitchen wastes, insects and microalgae can be used for the production of biodiesel (Yaakob, Mohammad, Alherbawi, Alam, & Sopian, 2013). To date, the major obstacle in the commercialization of biodiesel is the cost of production. In this regard, the exploitation of waste materials for the production of biodiesel might be useful to reduce the feedstock cost, which makes the process economical. The WCO is a waste, which can be converted into biodiesel and this will be helpful for the reduction of pollution since WCO is wasted into the environment. Secondly, the conversion of WCO into biodiesel will be a valuable addition of energy in existing energy grid (Arshad et al., 2018; Tangy, Pulidindi, & Gedanken, 2016). Moreover, under the current scenario of environmental pollution (Chham et al., 2018; Ghezali, Mahdad-Benzerdjeb, Ameri, & Bouyakoub, 2018; Ibisi & Asoluka, 2018; Mansouri et al., 2018; Mehta, Chandra, Mehta, & Maisuria, 2018; Ramdani, Benouis, Lousdad, Hamou, & Boufadi, 2018), there is need to adopt the clean and green processes as well as methodology. Various researchers studied different feedstock in order to convert free fatty acids (FFA) into methyl ester i.e., Che et al. (2012) used olive pomace oil for the production of FAME BY acid esterification process using sulfuric acid as a catalyst. They observed 50% reduction in FFA values at low methanol to oil ratio and over 80% reduction for high methanol to oil ratio. Similarly, Ouachab and Tsoutsos (2013) also studied the transesterification of olive pomace oil and achieved the FAME yield of 97.8%. Chai, Tu, Lu, and Yang (2014) also converted vegetable in to FAME and it was found that the 19.8:1 methanol to oil molar ratio worked well only within the FFA range of 15–25%, while the suggested 5% sulfuric acid worked well only within the FFA range of 15–35%. The FAME yields were 83.08%, 88%, 90%, 91.7%, 97.8% and 94% and 81.3% for the waste cooking oils using different catalyst (Table 1). So far, these studies revealed that WCO can be converted into FAME (Asri & Sari, 2015; Asri et al., 2015; Haigh et al., 2012; Noiroj et al., 2009; Saifuddin et al., 2009; Omar et al., 2009; Wang et al., 2006). This technique have been also employed for the production of biodiesel from non-cooking oils i.e., Mumtaz et al. (2016) utilized Eruca sativa oil for the production of biodiesel by Novozyme-435 lipase and Aspergillus niger lipase catalyzed transesterification. The biodiesel production was recorded 98.3% and 56.4% for oil catalyzed by Novozyme-435 and Aspergillus niger lipase, respectively. Similarly, animal bones modified with potassium hydroxide (KOH) as heterogeneous solid base catalyst for transesterification of non-edible Jatropha oil was used and FAME

2. Material and methods The WCO was collected from student cafeteria in the PARS campus, University of Agriculture, Faisalabad. Initially, the oil was filtered to remove all the insoluble impurities and heated at 100 °C to remove moisture. All the chemicals used were of analytical grade and purchased from Sigma-Aldrich, except as noted otherwise. 2.1. Pretreatment of WCO Pretreatment of WCO was done as reported elsewhere (Chai et al., 2014). For treatment, three neck reactor (250 mL) equipped with reflux condenser was used to avoid alcohol vaporization. The reaction contains 50 mL WCO, 10 mL methanol and 0.2% acid catalyst. The reaction mixture was fed into batch reactor and experiment was conducted at 50 °Cfor 6 h. Mineral acids (HCl, H2SO4 and H3PO4) were used for pretreatment. After stipulated time period, the samples were withdrawn and centrifuged. The methanol layer was drained off and the WCO was collected and washed with deionized water three times. The water content was removed by vacuum evaporation and the FFAs values were determined. Influencing parameters (methanol to oil ratio, catalyst dose, reaction time and temperature) were optimized and the FFA was calculated using the relation shown in Eq. (1).

Free fatty acid conversion (%) =

Ai −At × 100 Ai

(1)

Where, Ai and At, refer to the acidity (at zero and time t). 2.2. Trans-esterification of pretreated WCO KOH was mixed with methanol in a three neck batch reactor (250 mL) equipped with reflux condenser. The esterified oil was added in batch reactor and the reaction mixture was heated at required

Table 1 Literature survey of different processes used for the conversion of oils into biodiesel. S. No

Feedstock

Catalysts

FAME Yield

Ref.

1 2 3 4 5 6 7 8 9 10 11 12

Waste cooking oil = = = = = = = = = = = Non cooking oil = = = =

CaO/KI/γ-Al2O3 Lipase H2SO4 KOH/Al2O3 CaO/KI/γ-Al2O3 Acid-based catalyst Purolite D5081 Novozyme 435 H2SO4 Ferric suphate + acid catalyzed Acid catalyzed KOH Novozyme-435 Aspergillus niger KOH/calcined waste animal bones Acid Caustic

83.08 % 88 % 90% 91.7% 83% 97.8% 94% 90% 80% FFA reduction 81.3% FFA reduction 94% 98.3% 56.4% 96.1% 96% 94%

Asri et al. (2015) Saifuddin et al. (2009) Wang et al. (2006) Noiroj et al. (2009) Asri and Sari (2015) Ouachab and Tsoutsos (2013) Haigh et al. (2012) Haigh et al. (2012) Che et al. (2012) Omar et al., 2009 Chai et al. (2014) Present study Mumtaz et al. (2016) Mumtaz et al. (2016) Nisar et al., 2017 Kombe et al. (2012) Kombe et al. (2012)

13 14 15 16

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Where, B is the volume (mL) of 0.1 N Na2S2O3.5H2O for blank, S is volume (ml) of 0.1 N Na2S2O3.5H2O for sample (S), N is normality of Na2S2O3.5H2O solution and W is weight of biodiesel. Cetane number was calculated using the relation shown in Eq. (7) (Krishnangkura, 1989)

temperature with constant stirring for 1 h. Influencing parameters like methanol to oil ratio, catalyst dose, temperature and reaction time were optimized for biodiesel production process. Then, the reaction mixture was transferred to a separating funnel and mixture was separated into glycerol and biodiesel. After draining off the glycerol, the biodiesel was washed many times with 1:1 volume of water to remove excess methanol and catalyst. The biodiesel was then centrifuged at 4000 rpm for 10 min at room temperature and subjected to analysis (Anitha, 2012).

5458 ⎞−0.225 × IV Cetane Number = 46.3 + ⎛ ⎝ SV ⎠ Where, SV is the saponification value and IV is the iodine value.

2.3. Biodiesel analysis

3. Results and discussion

The solubility of biodiesel was checked in methanol. This test is used to evaluate the conversion of oil into diesel as the methyl esters (biodiesel) are soluble in methanol and triglycerides (animal and vegetable oils and fats) are not soluble in methanol (Al-Hamamre & Yamin, 2014; Lotero et al., 2005). The methanol was added in the biodiesel layer and shaken for 45 min and then allowed to settle. The unreacted oil settled down and biodiesel remains at the top. The unreacted oil was drained out and biodiesel is passed through the rotary evaporator to remove the dissolved methanol and biodiesel yield was calculated using relation shown in Eq. (2).

Yield (% ) =

Amount of biodiesel produced x 100 Amount of oil

3.1. Esterification conditions optimization The initial FFA value of WCO was 5.5 mg KOH/g, which indicates that the WCO was unsuitable for direct conversion into biodiesel using alkali catalyzed transesterification reaction. Hence pretreatment of WCO was done for the reduction of FFA contents and the FFA conversion rection is shown in Eq. (8). So far, a suitable catalyst is required for the reduction of FFA contents of the oil (Nisar et al., 2017, 2018). The WCO was pretreated with mineral acids (HCl, H2SO4 and H3PO4) to reduce the FFA contents. All the three acids showed good activity for the reduction of FFAs. Maximum conversion of FFA (70.7%) was observed in case of H2SO4 acid catalyzed reaction followed by the H3PO4 and HCl acids (60.1% and 52.7% respectively). These results in line with previous studies that acid pretreatments are effective for the reduction of FFA of oil i.e., Ouachab and Tsoutsos (2013) pretreatment olive pomace oil followed by alkali catalyzed transesterification and vegetable oils were also pretreated with acid and caustic. In view of significant reduction of FFA, the biodiesel yields were recorded up to 96% and 94% in acid and caustic pretreated oils, respectively (Kombe, Temu, Rajabu, & Mrema, 2012).

(2)

Specific gravity was determined using specific gravity meter (DA640 Kyoto Electronics Manufacturing C., Ltd). pH of the biodiesel was determined by pH measuring strips. Oxygen bomb calorimeter was used to determine the calorific value of biodiesel. The FAME composition was determined by Gas Chromatograph equipped with FID. Nitrogen was used as carrier gas. Initially, the oven temperature was set at 150 °C for 15 min, and then increased to 220 °C at 10 °C/min. The injector temperature was 250 °Cand detector temperatures was set at 300 °C. Fatty acid peaks were identified by comparison to the retention times of reference standards. For the determination of free fatty acid content, 0.5 g of biodiesel, 10 mL ethanol and 1–2 drops of phenolphthalein were used as indicator. The mixture was titrated against 0.1 N NaOH and change in color was noted. The FFA content was expressed g/100 g as oleic acid and calculated as shown in Eq. (3). The acid value was calculated using relation shown in Eq. (4).

FFA = v × N ×

28.2 w

R-COOH + R-OH → R-COO-R + H2O

(4)

For the determination of saponification value, the 0.5 g biodiesel and 20 mL of 0.5 N alcoholic (ethanol) KOH was mixed. The mixture placed in round bottom flask, refluxed and heated at 40 °C until clear solution, an indicated of saponification reaction. After cooling the contents, phenolphthalein was added as indicator and mixture was titrated against 0.5 N HCl until the pink color disappeared. The saponification value was determined using relation shown in Eq. (5).

56.1 w

(5)

Where, B and S are the blank and sample values (HCl), N is normality of HCl and W is weight of biodiesel. For the determination of iodine value, 0.1 g of biodiesel was mixed with 20 mL of CCL4 and 25 mL Wijs reagent flask, shaken and placed the flask in dark for 30 min. Then, 20 mL of 15% KI was added in reaction mixture followed by the addition of 100 mL distilled water. The contents were then titrated against 0.1 N Na2S2O3.5H2O using starch as an indicator. Disappearance of yellow color indicated the end point. Same procedure was repeated for blank except the addition of biodiesel and iodine value was calculated using relation shown in Eq. (6).

Iodine value (IV) =

[(B−S) × N × 12.69] w

(8)

The process variables which seriously influence the esterification of FFAs were optimized in this study. To check the influence of methanol amount, the experiment was conducted by varying the methanol to oil ratio from 1:10 to 1:2.5. The results indicated that as the methanol amount was increased, the FFAs reduced significantly. Theoretically, one mole of methanol is required for the esterification of one mole of FFA, however, excess amount of methanol results in enhanced FFA conversion. The FFAs conversion was increased to 80.2% from 42.2% as the methanol ratio increased to 1:2.5 from 1:1 (Fig. 1a). The maximum FFA conversion of 80.2% was achieved at methanol to oil ratio of 1:2.5 and these findings are in line with Ding, Xia, and Lu (2012). Amount of catalyst is also an important influencing parameter in the esterification process. To evaluate the effect of catalyst dose, the catalyst amount was studied up to 1% (Fig. 1b). The dose of catalyst is the volume fraction of oil in the reaction mixture. The results indicated that in the absence of catalyst, the conversion of FFA to esters was insignificant and the reaction mixture did not show any remarkable change in the amount of amount of FFA after completion of esterification reaction. Only 4.7% of FFA was esterified after 6 h without catalyst. The addition of H2SO4 acid accelerated the FFA conversion process. The FFA conversion was significant at higher dose of H2SO4. At 0.5% catalyst dose, 76% of the FFAs were esterified and at 1% catalyst dose, the conversion of FFA was 83.7%. Initially, the rate of esterification was fast and with time the rate of reaction reduced and became constant after extended period of time (up to 320 min). The effect of temperature was also investigated on the esterification process by varying the temperature (40–60 °C). The esterification process found to be highly temperature dependent. The higher esterification of FFA was observed at higher temperature and maximum esterification (88.8%) of FFA was observed at 60 °C. These findings are in line with previous studies that catalyst has significant effect on FFA esterification i.e., olive pomace oil

(3)

Acid value = FFA (%) × 1.989

Saponification value = (B−S) × N ×

(7)

(6) 222

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Fig. 1. (a) Effect of methanol to oil ratio on FFA conversion (50 °C; catalyst dose 0.5%) and (b) Effect of catalyst dose on FFA conversion (50 °C; methanol to oil ratio 2:2.5).

the FAME yield was enhanced (from 71% to 86%). However, further increasing the catalyst dose to 2%, the FAME yield was not changed significantly. It is reported that higher catalyst dose also favor the soap formation in the reaction mixture, which might decrease the FAME yield (Azeem et al., 2016). The reaction time also affected the FAME yield and results are shown in Fig. 2b. Initially, the transesterification process was fast and slowed down at later stage. A reaction time of 50 min was found suitable for higher FAME yield and by increasing the reaction time, there was no significant change in FAME yield. Temperature effect on FAME yield was also studied in the range of 30 °C to 60 °C. Reaction temperature also affected the FAME yield. FAME yield was increased from 80.4% to 94% as temperature was increased from 30 °C to 60 °C.

was treated with sulfuric acid and results revealed that FFA can be efficiently reduced with acid pretreatment (Che et al., 2012). Similarly, the acid pretreatment of olive pomace oil for the production of biodiesel was also promising (Ouachab & Tsoutsos, 2013). In another study, twostep process was adopted for the production of WCO biodiesel. The acid catalyzed pretreatment reduced the FFA of WCO significantly and resultantly, the FAME yield was enhanced considerably (Omar et al., 2009).

3.2. Biodiesel yield For transesterification, KOH was used as a catalyst to convert WCO into biodiesel. Important influencing parameters for transesterification include methanol to oil ratio, catalyst dose, temperature and reaction time were optimized. The amount of methanol is an important influencing factor in the process of transesterification (Omar et al., 2009). The effect of methanol to oil ratio was studied in the range of 1:12 to 1:1 and results are shown in Fig. 2a. The highest FAME yield was achieved at 1:3 methanol to oil ratio. Further increase in methanol concentrations decreased the FAME yield. The higher methanol to oil ratio might affect the solubility of glycerin and resultantly, FAME yield was decreased (Encinar, Gonzalez, & Rodriguez-Reinares, 2005). The catalyst dose effect was also checked on FAME yield. The KOH concentration was checked in the range of 0.5 to 2% of oil weight (Fig. 2b). Catalyst dose also affected the FAME yield. By increasing the catalyst amount from 0.5% to 1%,

3.3. Physico-chemical properties of biodiesel The density of biodiesel significantly affects the engine performance (Chhetri & Watts, 2008). The fuel density is effective in breaking up the fuel spray from the injector. The density of biodiesel was found to be 0.874 g/cm3, which was within the range of fuel standard (ASTM standard). The drop formation of biodiesel and quality of fuel air mixture combustion are dependent to the viscosity of fuel. Viscosity (very low/ high) is undesirable for the proper functioning of engine (Băţaga, Burnete, & Barabás, 2003). Low viscosity leads to low penetration, 223

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Fig. 2. (a) Effect of methanol to oil ratio on FAME yield (30 °C; catalyst dose 1%) and (b) Effect of catalyst dose on FAME yield (30 °C; methanol to oil ratio 1:03).

which results in the black smoke emission due to low combustion. A very viscous fuel may penetrate to the opposite wall of the injector, results in cold cylinder surface and leads to the low in combustion of fuel. The WCO biodiesel’s viscosity was found to be 5.83 mm2/s which is within the standard range of 1.9–6.0 mm2/s (ASTM D6751-02, 2002). Cloud point is defined as the temperature at which the crystals formation starts to form precipitate. The cloud point is the most commonly used measure of low-temperature operability of the fuel. Below the cloud point, the crystals might drop in the bottom of storage tank (Dwivedi & Sharma, 2016). So far, to run the engine below the cloud point of fuel, heating is necessary in order to avoid waxing of the fuel. The cloud point of biodiesel was found to be 10.5 °C, which is also under the recommended limits of biodiesel standard. Both the cloud point and pour points give indication of minimum temperature at which the fuel can ignite efficiently. At cloud point, the fuel can be used in acceptable conditions, but at pour point the fuel cannot be used. The pour point of WCO biodiesel is found to be 1 °C which is within the standard recommended range (Table 2). The calorific value of biofuels is an important parameter for the comparison of fuel properties with that of petroleum diesel (Drenth, Olsen, & Denef, 2015). The low energy contents of the biofuels affect the key performance parameters like maximum horsepower and torque (Drenth, Olsen, Cabot, & Johnson, 2014). Calorific value of WCO biodiesel was recorded to be 37.2 kJ/g, which is slightly lower than the petroleum diesel (41.2 MJ/kg), however, this value is acceptable for smooth engine performance (Al-Hamamre & Yamin, 2014). The acid value of synthesized WCO biodiesel was determined and it

Table 2 Fuel properties of biodiesel produced from waste cooking oil (WCO). Properties

Unit

Biodiesel from WCO

Biodiesel standards

Specific gravity Viscosity Calorific value Cloud point Pour point Acid value Saponification value Iodine value Cetane number

———— mm2/s kJ/g ᵒC ᵒC mg KOH/g mg KOH/g g I2/100 g oil ——

0.8743 5.83 37.2 10.5 1 0.6 280 63.5 51.48

0.86–0.9 1.9–6.0 > 35 −3 to 12 −15 to 10 < 0.8 < 312 < 120 ≥ 47

was found to be 0.6 mg KOH/g which is in standard range of biodiesel according to ASTM standards (ASTM D6751-02, 2002). The acid value of biodiesel is dependent upon the purification procedure. It is observed that acid value becomes higher if hot distilled water is used for the washing and purification. The saponification value is the amount of KOH (mg) required to saponify specific amount of biodiesel. It is reported that the pretreatment procedure of oil affects the saponification value (Predojevic & Skrbic, 2009). The saponification value of WCO biodiesel was 280 mg KOH/g which is within the standard range of biodiesel (< 320 mg KOH/g). Iodine value measures the amount of iodine in g absorbed by 100 g oil. It is a measure of degree of unsaturation of biodiesel hence helpful

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to investigate the stability of oil. High degree of unsaturation results in polymerization of fuel due to epoxide formation due to addition of oxygen in double bonds. The iodine value of WCO biodiesel was 63.5 g I2/100 g oil which was also within standard range of biodiesel. The cetane number of biodiesel depends on the carbon number of fuel and FAME concentration. The ignition quality of diesel depends on cetane number. For biodiesel, the recommended range of cetane number is 46–52 and 40–55 for conventional diesel. The cetane number of WCO biodiesel was 51.48, which is within the recommended range for biodiesel. The composition of WCO biodiesel was determined by GC by using FID detector. The methyl esters in WCO biodiesel were found to be of oleic acid (C18:1), linoleic acid (C18:2), palmitic acid (C16:0 and stearic acid (C18:0). The waste cooking oil is generated from the fried food. At high temperatures the composition changes along with organoleptic properties which affect both the food and oil quality. Reuse of oil may be harmful for because during recycling hazardous compounds are produced, which degrade the oil and food quality (Phan & Phan, 2008). So far, the alkali catalyzed process is a viable technique to convert WCO into biodiesel as and under the current issues of environmental pollution (Hiwot, 2017; Jafarinejad, 2017a, 2017b, Legrouri et al., 2017; Majolagbe, Adeyi, Osibanjo, Adams, & Ojuri, 2017; Ogundipe & Babarinde, 2017; Remya, Abitha, Rajput, Rane, & Dutta, 2017; Sasmaz, Dogan, & Sasmaz, 2016; Sasmaz, Akgül, Yıldırım, & Sasmaz, 2016; Sasmaz, Obek, & Sasmaz, 2016; Srikanth, Shyamala, & Rao, 2017; Ukpaka & Izonowei, 2017; Ukpaka, Adaobi, & Ukpaka, 2017), there is a need to adopt renewable energy sources and green technique for energy generation.

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