Towards Green Environment and Renewable Energy: Waste Vegetable Frying Oil for Biodiesel Synthesis

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1 Towards Green Environment and Renewable Energy: Waste Vegetable Frying Oil for Biodiesel Synthesis Eman A. Ashour 1, Maha A. Tony 2 1 Chemical Engineering Department, Faculty of Engineering, Minia University, Egypt 2 Basic Engineering Science Department, Faculty of Engineering, Shbin El-Koum, Minoufia University, Minoufia, Egypt maha_tony1@yahoo.com Abstract- In this study biodiesel was synthesized from waste cooking frying oil (WFO) collected from El-Minia city, Egypt by alkali-catalyzed transesterification. Optimization of reaction conditions such as catalyst amount, reaction temperature, reaction time and oil to methanol molar ratio have been studied. The best conversion value which getting the yield of 98.16% was obtained from 1.0% KOH catalyst was used at 3 hr of reaction time, the reaction temperature was 65 C and 1:6 oil to methanol molar ratio. Furthermore, different ratios of the WFO were blended with commercial diesel, namely, B10, B20, B30, B50 and without any addition which is called B100. Moreover, the physicochemical properties such as biodiesel viscosity, density, flash point, and higher heating value (HHV) of the obtained biodiesel were verified and compared with that of commercial diesel which recommending the use of the WFO biodiesel. Finally, the GHG (greenhouse gases emissions) of the WFO biodiesel advocate the biodiesel use. Keywords- Biodiesel, Transesterification, Waste cooking frying oil, greenhouses emissions. I. INTRODUCTION The global supply of oil and natural gas from the conventional sources is unlikely to meet the growth in energy demand over the next 25 years. Crude oil price reach a new high, the need for developing alternate fuels has become acute. Alternate fuels should be economically attractive in order to compete with currently used fossil fuels. Concern for the environment become necessity especially with the increasing emission of toxic chemicals from various industries and increasing concerns of global warming. Due to all of those reasons, there is ever growing urge to develop fuel substitutes that are renewable and sustainable [1]. Biomass derived fuels such as methane, ethanol, and biodiesel are well accepted alternatives to diesel fuels as they are economically feasible, renewable, environmentally friendly emission profile and is readily biodegradable and can be produced easily in developing areas [2]. Moreover, biodiesel fuel has become more attractive because of its environmental benefits [1, 3] due to the fact that plants and vegetable oils and animal fats are renewable biomass sources. Biodiesel represents a largely closed carbon dioxide cycle (approximately 78%), as it is derived from renewable biomass sources. Compared to petroleum diesel, biodiesel has lower emission of pollutants, it is biodegradable and enhances the engine lubricity and contributes to sustainability [4, 5]. Biodiesel has a higher cetane number than diesel fuel, no aromatics, no sulfur, and contains 10 11% oxygen by weight [6]. Huge quantities of waste cooking oils and animal fats are available throughout the world, especially in the developing countries. Management of such oils and fats pose a significant challenge because of their disposal problems and possible contamination of the water and land resources. Waste cooking oil arises from many different sources, including domestic, commercial and industrial. Even though some of this waste cooking oil is used for soap production, a major part of it is discharged into the environment. Thus, consuming it in the biodiesel production is one of the economical solutions to preserve the environment and solve the problem of the presence of such a problem in the environment. One of the major advantage of using biodiesel as an alternative fuel is reducing air contaminants (matter and volatile organic compounds) emitted from the use of petroleum diesel. Biodiesel offer a very promising alternative to diesel oil since they are renewable and have similar properties. Biodiesel (monoalkyl esters) is obtained by transesterification of triglyceride oil with alcohol in the presence of catalyst under suitable reaction condition. Transesterification is the process of transforming one type of ester into another type of ester. The reaction is catalyzed by the presence of the strong base, NaOH [2, 5-7]. Gui et al., in 2008, [8] recommended the use of waste edible oil as an ideal food stock to non-edible oil for biodiesel production. Chhetri et al., in 2008, [9] produced biodiesel (ethyl ester) which was prepared from waste cooking oil, the viscosity of the biodiesel ethyl ester was found to be 5.03 mm 2 /sec at 40 o C, however, the viscosity of waste cooking oil measured in room temperature was 72 mm 2 /sec, thus, they recommended the production of biodiesel from waste cooking oils for diesel substitute. Hossain and Boyce in 2009 [10] produced the biodiesel from pure sunflower cooking oil and waste sunflower cooking oil. Raja et al., in 2011 [11] demonstrated that the transesterification of Jatropha oil one Reference Number: JO-P

2 of the most promising options for the production of biodiesel for the use of conventional fossil fuels. Mahgoub et al., 2015 [12], demonstrated that the biodiesel produced from cooking vegetable oil reached to a conversion value of 96% form 0.35 wt% NaOH catalyst amount, 30 min reaction time, 55 C reaction temperature and 1:6 oil to methanol molar ratio. Abdelmoez et al., (2016) [13] claimed that Jojoba oil presented a qualified candidate for the production of biodiesel he maximum theoretical expected yields of methyl jojoboate, jojobyl alcohol and methanol recovery were found to be 99.14, 93.3 and 99.9%, respectively. Global biodiesel production is expected to reach 39 Billion L by 2024 corresponding to a 27% increase from 2014 (Fig. 1). The European Union is expected to be by far the major producer of biodiesel (Fig. 1) [14]. Figure (1): Estimated world distribution of biodiesel production and use in 2024 In the current work biodiesel derived from waste vegetable oil used in frying (WFO) is produced as alternative diesel fuel. The main components of waste cooking oils are triglycerides or also known as ester of fatty acid attached to glycerol. The produced biodiesel, which is characterized, was then blended in different ratios with commercial diesel. One of the main driving forces for biodiesel widespread is the greenhouse gas emission (CO 2 being the major one). This work will not only save environment but also cost. added per 100 ml of oil to neutralize the free fatty acids and to coagulate. Biodiesel production: The waste cooking frying oil (WFO) was obtained from local restaurants for fast food and houses in El-Minia City, Egypt. Firstly, the WFO was filtered to separate any food particles. Thereafter, WFO was heated to 110 C to remove water traces. Potassium methoxide solution was prepared by mixing a predetermined amount of methanol (20% by weight of oil) with KOH or NaOH (1.0% by weight of oil) in a container. The reaction was carried out for 3 h under at lower temperatures of 25 C. Stirring was started with the reaction at the moment of adding potassium methoxide solution until the predetermined reaction time, then nitrification with HCl was occurred. The mixture was carefully transferred to a separating funnel and allowed to stand there overnight. The lower layer, glycerol, was drained out, while, the upper layer the biodiesl was then cleaned thoroughly by washing with warm (86ºC) water for 15 minute with stirring and leave to separate for 2-3 hours and repeat this step for three times. The diesel was heated at ( ) until the color become clear. Thereafter, the quality and characteristics were checked. Blending biodiesel (B) with diesel by percentage (10%B, 20%B, 30%B and 50%B) by weight. Fig. 2 summarizes the conversion steps. The magnetic stirrer with hot plate, two necks round bottom flask, beakers, measuring cylinder, separating funnel, burette, funnels, measuring flask and thermometers were used. All the chemicals used were of analytical grade and supplied by Alfa chemicals Ltd. II. MATERIALS AND METHODS Production process: Transesterification- Is the process of chemically reacting a fat or oil with an alcohol in the presence of a catalyst. Alcohol used is usually methanol or ethanol and the catalyst is usually sodium hydroxide or potassium hydroxide. The main product of transesterification is biodiesel and the co-product is glycerin. Separation- After transesterification, the biodiesel phase is separated from the glycerin phase; both undergo purification. Neutralization- The waste vegetable oil contains free fatty acids in nature; it must be freed before taken into actual conversion process. The dehydrated oil is agitated with 4 % HCl solution for 25 minutes and 0.82 gram of NaOH was Figure (2): Flow chart for preparation of laboratory samples of WFO biodiesel Reference Number: JO-P

3 III. Biodiesel analysis Several parameters have been analyzed by specific method to verify whether the products fulfill the specification of standard methods. Kinematic viscosity, v, using Ubbelohde viscometer, density, ρ, using Pycnometer and heating value (heat of combustion which is resealed from the combustion of the unit value of fuel) using Cusson Calorimeter. Bomb calorimeter is used for measuring high calorific value. HHV. In addition, the flash point and spray test are recorded. The flash point temperature of a fuel is the minimum temperature at which the fuel will ignite (flash) on application of an ignition source. Flash point varies inversely with the fuel s volatility. Minimum flash point temperatures are required for proper safety and handling of diesel fuel. However, Viscosity affects the flash point. Pensky Martens Apparatus (closed Cup) is used to monitor the flash point. Moreover, the emission of greenhouses gases, GHG when the fuel is provided to an engine was analyzed using gas analyzer instrument (Ecom -J2KN analyzer). Such emissions are SO 2, CO, O 2, CO 2 and NO x. fixed at 1:6, 60 min and 65 C respectively. As results from Fig. 3, increase of catalyst amount from 0.6 to 1.0% (weight of catslyst / weight of oil) resulted in increase of biodiesel yield. As illustrated in Fig 3a the yield increased in the case of using KOH from to %. However, in the case of using NaOH (Fig. 3b) the yield increased from 85.9 to %. However, the biodiesel yield decreased as the catalyst amount increase above 1.0% (96% yield for 1.2% KOH catalyst amount and 86% for 1.2% NaOH catalyst amount). Optimization of Reaction Time- Fig.4 shows the influence of reaction time on biodiesel yield. Oil to methanol molar ratio, catalyst KOH amount and reaction temperature were fixed at 1:6, 1.0 wt% and 65 C respectively. The optimal conversion for WFO biodiesel was obtained at 3 hr reaction time which gave a maximum yield of 96.30% (Fig. 4). We observed that if the reaction time exceeded 3 hr, the conversion value decreased and for higher reaction time the conversion remained stable. This fact could be explained by possibility of the reverse reaction [15]. IV. Results and discussions: Optimization of catalyst type and amount- Fig. 3 shows the influence of catalyst amount and type on biodiesel yield. Oil to methanol molar ratio, reaction time and temperature were Figure (3): Effect of catalyst amount and type on the biodiesel yield (a) KOH; (b) NaOH Reference Number: JO-P

4 Optimization of Reaction Temperature- Fig.6 shows the influence of reaction temperature on biodiesel yield. Oil to methanol molar ratio, catalyst amount and reaction time were fixed at 1:6, 1.0 wt% and 1 hr, respectively. The reaction was carried out at 25, 40, 55, 65 and 70 C to evaluate the influence of reaction temperature. The optimal conversion for WFO biodiesel was obtained at 65 C, which gave a maximum yield of 96.15%. The conversion value decreased if the reaction temperature exceeded 65 C. Figure (4) Effect of conversion time on the biodiesel yield Optimization of Oil: Methanol molar ratio- Theoretically the transesterification reaction requires three moles of methanol and one mole of triglyceride in the presence of catalyst to yield three moles of biodiesel and one mole of glycerol. The transesterification is reversible and higher amounts of methanol to oil molar ratio can shift the equilibrium to the product side. Fig.5 shows the influence of reaction temperature on methyl esters yield. Catalyst amount, reaction temperature and reaction time were fixed at 1.0 wt%, 65 C and 1 hr respectively. The reaction was carried out at 1:3, 1:4, 1:5, 1:6, 1:9 and 1:10 (oil to methanol molar ratio). The conversion increased as the oil to methanol molar ratio increases and reaches 98.16% at 1:9 molar ratio. The conversion did not vary significantly above this molar ratio. Figure (6): Effect of reaction temperature on biodiesel yield Physico-chemical analysis- The physicochemical properties of WFO are given in Table 1 compared to those properties of commercial diesel and ASTM standards. It is clear that the biodiesel obtained from WFOs meets the standards specified by ASTM D6571. The heating value is obtained by the complete combustion of a unit quantity of solid fuel in oxygen bomb calorimeter. The HHVs of biodiesel (37520 KJ/kg) is slightly lower than that of diesel (46221 KJ/kg). The oxygen content of biodiesel improves the combustion process and decreases its oxidation potential. The structural oxygen content of a fuel improves its combustion efficiency due to an increase in the homogeneity of oxygen with the fuel during combustion. Because of this the combustion efficiency of biodiesel is higher than that of petrodiesel. Figure (5): Effect of oil: methanol molar ration on yield Table (1): Physicochemical properties of WFO, commercial diesel and WFO biodiesel Properties Raw WFO ASTM D6571 Commercial diesel WFO Biodiesel (B100) (B50) (B30) (B20) (B10) Kinametic viscosity, v, mm 2 /S@40 C Specific density, Ρ, C Flash point, C HHV, KJ/kg Reference Number: JO-P

5 Greenhouse Gas Emissions, GHG- Table 2 illustrated the greenhouse gases for different biodiesel (WFO) and compared to commercial diesel. Greenhouse gases trap heat from the sun and warm the earth s surface. Greenhouse gas emissions, the majority are related to energy consumption, and most of those are carbon dioxide. Table 2. Biodiesel GHG Emission Emission CO, rpm of engine Commercial diesel WFO Biodiesel (B10) (B20) (B30) (B50) NO, ppm SO 2, % CO 2, % C x H y, % T air, C T gas, C Reference Number: JO-P

6 The GHG reduction when using biodiesel is obtained by comparing GHG emissions related to biofuels missions with conventional diesel or gasoline. As stated in literature, diesel vehicles are % in GHG emissions reduction than using gasoline vehicles, however, using biodiesel can result in further decrease, which could be reached to 60% reduction in GHG emissions [16]. This could be illustrated by that during this process hydrogen replaces other atoms such as sulfur, oxygen and nitrogen and converts the oil s triglyceride molecules into paraffinic hydrocarbons [17]. Biodiesel fuel offers a variety of energy security, economic and environmental benefits. From an environmental perspective, biodiesel can reduce emissions of hydrocarbon, carbon monoxide and particulate matter. VI. CONCLUSION In the current investigation, it has confirmed that waste fryer cooking edible oil is recommended to be an alternative ideal option for non-edible biodiesel production. The experimental result shows that alkaline catalyzed transesterification is a promising area of research for the production of biodiesel. GHG are recorded and confirming the use of biodiesel from waste cooking frying oil. VII. REFERENCES [1] A. Demirbas, Biofuels from Vegetable Oils via Catalytic and Non-Catalytic Supercritical alcohol Transesterifications and Other Methods: A Survey, Energy Conversion and Management, 44, , [2] Y. Zhang, Dube M. A. Mclean D. D. and M. Kates, Biodiesel production from waste cooking oil: Process design and technological as- assessment, Bioresource Technology, 89, 1-16, [3] G. Lean, Oil and gas may run short by The Independent, UK, 2007, ticle ece, (Accessed on 23 July 2007). [4] A. Kurki, A. Hil and M. Morris, Biodiesel: The sustainability dimensions. ATTRA Publication #IP281, 2006, [5] M. I Khan, A. B. Chhetri, M. R. Islam, Analyzing Sustainability of Community Based Energy Technologies, Energy Sources, 2, , [6] M. Canakci, The Potential of Restaurant Waste Lipids as Biodiesel Feedstocks. Bioresource Technology, 98, , [7] H. Blanco-Canqui, and R. Lal, Soil and crop response to harvesting corn residues for biofuel production, Geoderma, 141, , [8] M. M. Gui, K.T. Lee and S. Bhatia, Feasibility of edible oil vs. non-edible oil vs. waste edible oil as biodiesel feedstock, Energy, 33(11), , [9] A. B. Chhetri, K. Chris Watts and M. Rafiqul Islam, Waste Cooking Oil as an Alternate Feedstock for Biodiesel Production, Energies 2008, 1, 3-18 [10] A. B. M. S. Hossain and A.N. Boyce, Biodiesel production from waste sunflower cooking oil as environmental recycling process and renewable energy, Bulgarian Journal of Agricultural Science, 15 (4), , [11] S. Antony Raja, D. S. Robinson and C. L. Samr, R. Lee, Biodiesel production from jatropha oil and its characterization, Research Journal of Chemical Sciences, 1 (1), [12] H. A. Mahgoub, N. A. Salih and A. A. Mohammed, Suitable Condition of Biodiesel Production from Waste Cooking Oil Al-Baha City KSA, International Journal of Multidisciplinary and Current research, 3, , [13] W. Abdelmoez, A.M. Tayeb, A. Mustafa and M.d Abdelhamid, Green Approach for Biodiesel Production from Jojoba Oil Supported by Process Modeling and Simulation, International Journal of Chemical Reactions and Engineering, 2016; DOI: /ijcre [14] Source: OECD/FAO (2015), OECD-FAO Agricultural Outlook, OECD Agriculture statistics (database), [15] A. Vanoiu, Schmidt, A., Peter, F., Rusanc, L.M. and Ungurean, M., Comparative study on biodiesel synthesis from different vegetable oil, Chemical Bulletin., 56 (70), 94-98, [16] K. Sivaramakrishnan and P. Ravikumar, Determination of higher heating value of biodiesels, International Journal of Engineering Science and Technology (IJEST), 3(11), , [17] J.M. López, A. Gomez, F. Aparicio and F.J. Sánchez, Comparison of GHG emissions from diesel, biodiesel and natural gas refuse trucks of the City of Madrid, Applied Energy, 86, , Reference Number: