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Optimization of Cottonseed Oil Ethanolysis to Produce Biodiesel High in Gossypol Content
Abstract
Transesterification of cottonseed oil was carried out using ethanol and potassium hydroxide (KOH). A central composite design with six center and six axial points was used to study the effect of catalyst concentration, molar ratio of ethanol to cottonseed oil and reaction temperature for percentage yield (% yield) and percentage initial absorbance (%A
385nm) of the biodiesel. Catalyst concentration and molar ratio of ethanol to cottonseed oil were the most significant variables affecting percentage conversion and %A
385nm. Maximum predicted % yield of 98% was obtained at a catalyst concentration of 1.07% (wt/wt) and ethanol to cottonseed oil molar ratio of 20:1 at reaction temperature of 25 °C. Maximum predicted %A
385nm of more than 80% was obtained at 0.5% (wt/wt) catalyst concentration and molar ratio of 3:1 at 25 °C. The response surfaces that described % yield and %A
385nm were inversely related. Gossypol concentration (% wt), oxidative stability and %A
385nm of biodiesel were found to be highly correlated with each other. Hence, color %A
385nm is a measure of the amount of pigments present in biodiesel fuels that have not yet been subjected to autoxidation. High gossypol concentration also corresponds to a fuel with high oxidative stability. The fatty acid ethyl esters (FAEE) produced from cottonseed oil had superior oxidative stability to fatty acid methyl esters (FAME) produced from cottonseed oil.
... Most of biodiesel-producing countries today with the exception of Brazil use methanol, a toxic and fossil fuel-derived alcohol, for converting triglycerides of oil and fat feedstocks to methyl ester biodiesel. Methanol is currently produced inexpensively from petroleum sources including coal and natural gas, but with rapidly increasing oil prices, methanol costs are expected to increase [12]. Replacement of methanol by biomass-derived ethanol could further reduce greenhouse gas emissions from fossil fuel products. ...
... Studies have been made to replace methanol using safe and renewable alcohol alternative in the form of ethanol [4,12,15,16,29,31,32]. However, Philippines which exports about 80% of its copra production and one of the largest producer of coconut oil in the world has yet to conduct detailed research on coconut ethyl ester biodiesel [8,21]. ...
... Properties of the coconut oil feedstock are shown in Table 1. [4,12,22,32]. In this study, the choice of catalyst and its amount including that of the percentage excess of ethanol were influenced by the experiments conducted by Petersen [22]. ...
The study describes the production of ethyl ester biodiesel from refined coconut oil. It aimed to replace the toxic methanol by a renewable and relatively safe ethanol and to determine whether the product properties conform to Philippine National Standard (PNS) specifications for B100 fatty acid methyl ester biodiesel. Emission characteristics of the biodiesel were also studied using a single-cylinder engine generator set fueled with neat diesel, B1, B2, and B5 biodiesel blends, at 61%, 77%, and 93% electrical loads, which are low, medium, and high load respectively. Successful conversion via base-catalyzed transesterification was carried at process conditions of 1% (weight to oil) KOH catalyst, 59% excess ethanol, 1.5 hours reaction time and ambient temperature at mixer setting of about 4500 rpm with a yield of 93.64% ester. Several properties of the produced coconut ethyl ester conformed to PNS specifications with the exception of cetane index, acid value, water content, and total glycerine content. The calculated cetane index was 46.327 which is close to US and Brazil standards for cetane number. Emission tests revealed that the B1 blend had the optimal emission characteristics with most of the parameters while B2 blend had the most significant decrease in CO emission. B1 reduced CO2 emission by 8%, NOx at 7% and THC by 2.5% at high load when compared to base petro diesel. B2 blend reduced CO emission significantly by 46% at low load and 22% at medium load when compared to base petro diesel. The remaining B2 and B5 blends had an average increase of about 10% and 16% NOx emissions respectively, a typical characteristic for most biodiesels.
... Biodiesel is a mono alkyl ester of long chain fatty acid (methyl, ethyl, or propyl) mainly derived from alcoholysis of tri-alkyl glycerides (TAG) of vegetable oils (e.g. peanut oil, cottonseed oil, soybean oil, palm oil) or animal fats [3], [4]. It is produced mainly through transesterification reaction comprising feedstock and alcohol in the presence of a catalyst (methanol, ethanol or enzyme), on the other hand, it can also be produced through direct blending, micro emulsification and pyrolysis [5]. ...
... Similarly, Fan et al. [1] used RSM technique and obtained optimum biodiesel yield (97%) at 7.9:1 methanol oil ratio, 1.0% catalyst weight, 53°C temperature, 268 rpm mixing speed and 45 min reaction time. Moreover, the biodiesel yield, temperature and reaction time of the biodiesel production were further reduced when Joshi et al. [4] utilized central composite design (CCD) method to enhance the production of biodiesel using high gossypol content cottonseed oil. They achieved a maximum biodiesel yield of 98% at 20:1 methanol oil ratio, 1.07% catalyst weight, 25°C temperature and 30 min reaction time. ...
... The experimental and predicted biodiesel yields (%) are presented in Table 2. The empirical correlation between the biodiesel yield (%) in terms of coded independent factors is described by (4) where A, B, C and D are the methanol/oil ratio, catalyst wt., temperature and time respectively. The optimum biodiesel yield (%) can be estimated by equation 4 using the best values of the model variables and their interactive effects within the initial boundary conditions of the model. ...
Cheap raw materials and optimum process conditions of a transesterification reaction continued to be the most essential factors in determining the production of the biodiesel in commercial quantity to meet up the current global demand. In this study the crude cottonseed oil was used as an economical feedstock for biodiesel production since its demand as a cooking oil has reduced due to health issues related to its consumption. The process variables affecting the transesterification reaction such as methanol/oil ratio (4:1-9:1 mol/mol), catalyst weight (0.5-2%), temperature (40-65°C), reaction time (50-120 min) were optimized using rotatable central composite design of the response surface methodology in order to enhance the percentage yield of the biodiesel production. The maximum biodiesel yield (93.34%) was achieved under 8.08:1 mol/mol methanol/oil ratio, 1.87% catalyst weight, 40°C reaction temperature and 120 min reaction time. The properties of the biodiesel produced which include kinematic viscosity, density, cloud point, pour point and flash point were determined and compared with the European fatty acid methyl ester standard.
... The yield of biodiesel is a function of a number of variables such as operation temperature, ethanol:oil ratio, and catalyst amount. Even though the operating conditions have been studied, 26,27 they have been optimized only in the context of the reactor to obtain approximately 90-98% oil conversion to ethyl esters using different alkali catalysts without considering the energy required in the separation stages. There are a number of tradeoffs to obtain a high yield by adjusting the catalyst concentration, ethanol; oil ratio and working temperature. ...
... The catalyst used is KOH because K 3 PO 4 can be easily separated and used as fertilizer. The model for the transesterification reaction, 27 Eq. 1, is taken from the literature and Table 1 Ethanol Recovery. A distillation column will be used to recover the excess of ethanol so that it is recycled back to the reactor. ...
... Out of the four alternatives (alkali, heterogeneous or enzymatic catalyzed and noncatalyzed under supercritical Alkali (27,39) Supercritical (39,40) Enzymatic (37) Heterogeneous (44) KOH conditions), there are two that are promising in terms of production cost, the alkali catalyzed and the enzymatic catalyzed. The production cost using ethanol is slightly higher than the values obtained when using methanol as the raw material (Martín and Grossmann 20 ) due to the current higher cost of ethanol. ...
Biodiesel, along with bioethanol, are the two most promising biofuels in today's market. Vegetable oils hold promise as alternative fuels for diesel engines. However, using raw vegetable oils for diesel engines can cause numerous engine-related problems. Thus, research has focused on developing transformation processes like pyrolysis, micro emulsion and transesterification. The process of transesterification has been most widely used. It removes glycerol from the triglycerides, and replaces it with radicals from the alcohol used for the conversion process. As the source of oil we consider algae for several reasons such as the fact that microalgae convert sunlight, nutrients and CO2 into proteins carbohydrates and lipids with a growth rate that doubles their biomass up to five times a day. Algae can grow not only on normal carbon sources, such as glucose, fructose, etc, but on waste from agriculture and food industries. It is also possible to use saline water or wastewater, eliminating the problem of water usage and lowering the cost of microalgae oil, algae growth can also be used to treat water in order to remove pollutants such as NH4+, NO3-, PO43-. Finally, the yield of biofuel for algae per area is between 10 and 100 times higher than conventional raw materials for biodiesel, and between 3 and 10 times higher than conventional raw materials for ethanol. Thus, it is expected that algae oil will be capable of meeting the US diesel need with 2-5% of the current US cropland. For quite some time the use of methanol in the transesterification process has been based on its lower cost and quicker reaction times compared to ethanol. However, methanol is currently produced mainly from non renewable sources which implies that the production of biodiesel using methanol is highly dependent on fossil fuels. Current biorefineries are becoming petrochemical complexes where a number of different products including bioethanol and biodiesel are produced. Furthermore, lately it has been reported that similar yields of biodiesel can be obtained using either ethanol or methanol as the transesterification agent. Therefore, in order to avoid the dependence on fossil fuels, we investigate the integration of the use of bioethanol in the production of biodiesel because the use of bioethanol can result in a large economical benefit in the actual operation of the complex. In this paper we optimize the production of biodiesel applying simultaneous optimization and heat integration followed by minimization of freshwater consumption. The proposed superstructure produces biodiesel from algae oil using bioethanol by defining the best transesterification technology and the operating conditions at the reactor including the products separation stages. We first grow the algae in ponds, dehydrate them and extract the oil. Next, we considered four different transesterification paths: alkali, enzymatic and heterogeneous catalysts and under supercritical conditions. The reactors are modelled using response surface methodology based on experimental results from the literature to account for the effect of different variables such as operating temperature, excess of ethanol, catalyst load, time and pressure. These reactor models are implemented together with short-cut methods, experimental and rules of thumb based models for the recovery of ethanol, the separation of the polar and non polar phases and the final purification of the biodiesel and glycerol produced to formulate the problem as a superstructure of alternatives. The aim of this paper is to simultaneously optimize and heat and water integrate the production of biodiesel using ethanol in terms of the reaction technology and the operating conditions. Due to the simultaneous optimization and heat integration, the optimal conditions in the reactors differ from the ones traditionally used because our results take the separation stages into account. In terms of the best process, the alkali catalyzed process is the most profitable, while the enzymatic based one is even more promising due to the lower consumption of energy and water. However, it requires that the enzyme cost to be reduced. Finally, only for production costs of bioethanol below $0.5/gal will this process become economically competitive with that using methanol. On the one hand, his value is in the range of some of the values reported in the recent literature for bioethanol production. Furthermore, this process does not depend on fossil fuels nor on fossil fuel based intermediates.
... The yield of biodiesel is a function of a number of variables such as operation temperature, ethanol:oil ratio, and catalyst amount. Even though the operating conditions have been studied, 26,27 they have been optimized only in the context of the reactor to obtain approximately 90-98% oil conversion to ethyl esters using different alkali catalysts without considering the energy required in the separation stages. There are a number of tradeoffs to obtain a high yield by adjusting the catalyst concentration, ethanol; oil ratio and working temperature. ...
... The catalyst used is KOH because K 3 PO 4 can be easily separated and used as fertilizer. The model for the transesterification reaction, 27 Eq. 1, is taken from the literature and Table 1 Ethanol Recovery. A distillation column will be used to recover the excess of ethanol so that it is recycled back to the reactor. ...
... Out of the four alternatives (alkali, heterogeneous or enzymatic catalyzed and noncatalyzed under supercritical Alkali (27,39) Supercritical (39,40) Enzymatic (37) Heterogeneous (44) KOH conditions), there are two that are promising in terms of production cost, the alkali catalyzed and the enzymatic catalyzed. The production cost using ethanol is slightly higher than the values obtained when using methanol as the raw material (Martín and Grossmann 20 ) due to the current higher cost of ethanol. ...
... A literature survey on optimization of base-catalyzed ethanolysis of both edible and non-edible vegetable oils is presented in Table 1. These studies were related to the ethanolysis of sunflower [8], soybean [3,19], rapeseed [20], castor [21][22][23], Brassica carinata [8], cottonseed [24] and Raphanus sativus [25,26] oils catalyzed with potassium and sodium hydroxides or ethoxides in different and wide ranges of ethanol-to-oil molar ratio and reaction temperature. The influence of ethanol-to-oil molar ratio, catalyst loading, reaction temperature, mixing intensity and reaction time were the most frequently examined factors affecting the FAEE yield. ...
... Only Silva et al. [3] used a 2 4 central composite design with four factors (temperature, reaction time, alcohol-to-oil molar ratio and catalyst loading), while Valle et al. [26] applied a 2 (5À1) fractional factorial design which included five factors (agitation speed being the fifth variable). No research has been performed with four factors at three levels despite several studies have shown the existence of a significant curvature in the case of some vegetable oils [3,8,19,[21][22][23][24]. There is no example in the literature involving the 3 3 full factorial design and the RSM for base-catalyzed ethanolysis of vegetable oils. ...
... According to the most researches, catalyst loading and ethanolto-oil molar ratio have the greatest effect on the FAEE yield, although there are a couple of studies pointing out ignorable impacts of the latter factor [8,20,26]. Catalysts are normally expected to have a positive effect on the FAEE formation, although the negative effect was found in the ethanolysis of rapeseed [20] and cottonseed [24] oils. KOH has a positive catalytic impact on FAEE yield, independently of the type of oil [8]. ...
... Biodiesel is a renewable fuel that can be used as a substitute of petroleum diesel. It is also comprised of mono-alkyl esters of long chain fatty acids obtained from vegetable oils or animal fats, following the requirements of the American Society for Testing and Materials (ASTM D6751-12) [5][6][7][8][9]. Indeed, biodiesel can be produced by transesterification of triglycerides of vegetable oils with a short-chain alcohol, such as methanol or ethanol [10,11]. ...
... Joshi et al. [8] studied the optimization of cottonseed oil transesterification and the effects evaluated on biodiesel formation were catalyst concentration, oil/ ethanol molar ratio and reaction temperature. According to the authors, catalyst concentration and oil/ethanol molar ratio were the most significant variables affecting oil conversion. ...
This study aimed to evaluate the kinetic behavior of cottonseed oil transesterification with ethanol based on a pseudo first order kinetic model. A 2³ factorial planning with three central points was performed by considering temperature, catalyst concentration and alcohol/oil molar ratio as dependent variables and biodiesel concentration as response signal. It was observed that the highest conversion was obtained for the following conditions: temperature between 50 and 70 °C, high alcohol/oil molar ratio and low percentage of catalyst. All samples were collected during time intervals of 5–10–15–30–60 and 90 min. A set of kinetic constant values were obtained for each operating condition ranging from 72 to 23l min⁻¹. Indeed, it was possible to obtain the kinetic parameters frequency factor k0 = 5807.05 dm³*mol⁻¹*min⁻¹ and Ea = 16.84 kJ*mol⁻¹ for biodiesel production with ethanol.
... Kose et al. [46] investigated cottonseed oil as feedstock for the production of cottonseed oil fatty acid methyl esters; Meneghetti et al. [47] synthesized castor and cottonseed oil ethyl esters using castor and cottonseed oils as feedstock; Hem et al. [48] used cottonseed oil and synthesized biodiesel; Mohammed et al. [49] reported castor oil as potential raw material for biodiesel. Kulkarni et al. [50] reported the feasibility of canola oil as feedstock for biodiesel production. ...
... RSM has been employed by numerous researchers to optimize the reaction parameters involved in the biodiesel production process, e.g., methanolysis of B. carinata oil was optimized using RSM for biodiesel production by Gemma et al. [58]. Hem et al. [48] reported the optimized biodiesel production from cottonseed oil; CCD comprising eight factorial points, six axial points, and six replicated center was employed for the optimization of reaction temperature, catalyst concentration, and ethanol to oil molar ratio. The authors reported 98% yield of biodiesel under the reaction conditions, i.e., catalyst concentration (1.07%), ethanol to oil molar ratio (20:1), and reaction temperature (25 C). ...
Recent worldwide energy crises have provoked the development of alternative energy sources. Biodiesel is gaining acceptance worldwide as an alternative fuel usually synthesized by chemical/biochemical transesterification of vegetable oils/animal fat. Chemically, acids, alkalis, and metal oxide are being used to catalyze transesterification reactions in addition to the heterogeneous catalysts, whereas biochemically enzymes are used. Chemical transesterification reactions present several disadvantages, i.e., need to remove inorganic salts, high temperature, and undesirable side reactions. Therefore considering the ecological and economic perspectives, researchers are considering enzyme-catalyzed reactions for biodiesel production with advantages such as enzyme specificity, reuse ability, genetically improved efficiency, mild reaction conditions, ability to accept new substrates, natural and thermal stability, and capability to catalyze green reactions. This chapter therefore summarizes recent trends, analytical technicalities, and future prospective of chemical and enzymatic routes in addition to optimization techniques, fuel characteristics, and emission profiles of biodiesel as sustainable fuel.
... In Contrast, transesterifying cottonseed oil by microwave irradiation could produce a biodiesel yield in the range of 89.5-92.7% [13]. No matter what kind of catalysts or approaches were applied, all those studies aimed to produce high yield of biodiesel by optimized reaction conditions based on optimized parameters in terms of alcohol/oil molar ratio, catalyst concentration, reaction temperature, and time. ...
... It is stirred for five to ten minutes (methanol is a polar compound; oil is strongly non-polar; hence a suspension will form). One milliliter of 95% pure sulfuric acid (H 2 SO 4 ) is added for each liter of oil using a graduated eye dropper [13]. The compound is stirred for one hour maintaining the temperature at 35°C. ...
... The model for the transesterification reaction is developed based on a design of experiments methods using data from the literature. 36,37 Table 1 shows the range of operation of the variables and the units. ...
... Furthermore, in order for the facility to operate, we need ethanol for the transesterification of the oil and, thus, ethanol is also produced. However, the yield to biodiesel that can be obtained, based on experimental results, 36,37,44 is slightly higher in the case of using alkali catalyst and, therefore, more ethanol is consumed to produce biodiesel. In Table 7, we present the optimal operating conditions of the multi-effect columns, very similar in both cases which also validate the sequential approach used in previous papers by the authors for the dehydration of the ethanol produced either by sugars or syngas fermentation. ...
The optimization of the composition of the algae for the simultaneous production of bioethanol and biodiesel is presented. We consider two alternative technologies for the biodiesel synthesis from algae oil, enzymatic or homogeneous alkali catalyzed that are coupled with bioethanol production from algae starch. In order to determine the optimal operating conditions, we not only couple the technologies, but simultaneously optimize the production of both biofuels and heat integrate them while optimizing the water consumption. Multi-effect distillation is included to reduce the energy and cooling water consumption for ethanol dehydration. In both cases, the optimal algae composition results in 60% oil, 30% starch, and 10% protein. The best alternative for the production of biofuels corresponds to a production price of 0.35 $/gal, using enzymes, with energy and water consumption values (4.00 MJ/gal and 0.59 gal/gal). © 2013 American Institute of Chemical Engineers AIChE J, 59: 2872–2883, 2013
... Base-catalyzed ethanolysis of vegetable oils has been already optimized using different statistical models [1][2][3][4][5][6][7][8][9][10][11][12]. The 2 3 full factorial design, combined with the RSM has been mainly used [1][2][3][4][5][6][7][8][9], although Silva et al. [10] applied a 2 4 central composite design, and Valle et al. [11] employed a 2 fractional factorial design. ...
... Base-catalyzed ethanolysis of vegetable oils has been already optimized using different statistical models [1][2][3][4][5][6][7][8][9][10][11][12]. The 2 3 full factorial design, combined with the RSM has been mainly used [1][2][3][4][5][6][7][8][9], although Silva et al. [10] applied a 2 4 central composite design, and Valle et al. [11] employed a 2 fractional factorial design. Only Veličković et al. [12] have recently used a 3 3 full factorial design of experiments to optimize the base-catalyzed ethanolysis of sunflower oil. ...
... Consequently, the transformation of cotton seed to fuel will not has a great impact on the food industry. The oil content of cotton seed is approximately 17-21% (Kilickan and Guner, 2006;Putun et al., 2006), and the oil contains palmitic acid (22-27%), stearic acid (2-5%), oleic acid (15-20%), linoleic acid (49-58%) with traces of arachidic acid, behenic acid and so on (Joshi et al., 2008;Rashid et al., 2009). Therefore, cotton seed with high calorific value can be transformed into biofuels via various conversion technologies, such as transesterification of cottonseed oil to biodiesel fuel (Joshi et al., 2008;Keera et al., 2011;Prakash et al., 2010;Rashid et al., 2009); pyrolysis of cotton seed or cottonseed oil to bio-oils (Li et al., 2009;Putun, 2010); pyrolytic conversion of cottonseed cake to bio-oils (Ozbay et al., 2006(Ozbay et al., , 2001Pütün et al., 2006), and so on. ...
... The oil content of cotton seed is approximately 17-21% (Kilickan and Guner, 2006;Putun et al., 2006), and the oil contains palmitic acid (22-27%), stearic acid (2-5%), oleic acid (15-20%), linoleic acid (49-58%) with traces of arachidic acid, behenic acid and so on (Joshi et al., 2008;Rashid et al., 2009). Therefore, cotton seed with high calorific value can be transformed into biofuels via various conversion technologies, such as transesterification of cottonseed oil to biodiesel fuel (Joshi et al., 2008;Keera et al., 2011;Prakash et al., 2010;Rashid et al., 2009); pyrolysis of cotton seed or cottonseed oil to bio-oils (Li et al., 2009;Putun, 2010); pyrolytic conversion of cottonseed cake to bio-oils (Ozbay et al., 2006(Ozbay et al., , 2001Pütün et al., 2006), and so on. ...
Deoxy-liquefaction of cotton seed in husk was carried out to produce hydrocarbon oil at different temperatures (400-500°C). Results indicated that at 450°C, the obtained oil had a maximum alkanes value of 49.58% with a low oxygen content (1.4%) resulting in the increase of HHV (43.8MJkg(-1)), whereas the oil contained considerable nitrogenous compounds. In the presence of γ-Al2O3-CuO catalyst, at 450°C nitrogen content in the oil dropped 20%, exhibiting the activity of catalysis for denitrification, when the content of alkanes rose to 54.91%; by vacuum distillation, the oil was then separated into light/heavy fractions which showed that they both possessed rich carbon and hydrogen with low oxygen contents. The light fractions were much the same as that of gasoline, while the heavy fractions were close to diesel, which laid the foundation of further treatment and applications.
... The classic conditions for ethanolysis of vegetable oils or animal fats are 6:1 molar ratio of ethanol to oil, 0.5 wt.% catalyst (with respect to TAG), 600+ rpm, 75°C reaction temperature, and 1 h reaction time to produce fatty acid ethyl esters (FAEE) and glycerol (Freedman et al. 1984). Ethyl esters have been prepared from a number of feedstocks for use or evaluation as potential biodiesel fuels (Schwab et al. 1987;Peterson et al. 1996;Foglia et al. 1997;Wu et al. 1998;Nimcevic et al. 2000;Lang et al. 2001;Lee et al. 2002;Encinar et al. , 2007Zhou et al. 2003;Mariod et al. 2006;Meneghetti et al. 2006;Dantas et al. 2007;Issariyakul et al. 2007;Kucek et al. 2007;Kulkarni et al. 2007;Kumari et al. 2007;Moreira et al. 2007;Alamu et al. 2008;Domingos et al. 2008;Georgogianni et al. 2008;Hamad et al. 2008;Joshi et al. 2008Joshi et al. , 2009Lima et al. 2008;Rodrigues et al. 2008;Rosa et al. 2008;Stavarache et al. 2008). In addition, mixtures of methyl and ethyl esters have been reported whereby the transesterification reaction was conducted with both methanol and ethanol (Issariyakul et al. 2007;Kulkarni et al. 2007;Joshi et al. 2009). ...
... In addition, mixtures of methyl and ethyl esters have been reported whereby the transesterification reaction was conducted with both methanol and ethanol (Issariyakul et al. 2007;Kulkarni et al. 2007;Joshi et al. 2009). As in the case of methanolysis, the ethanolysis reaction has been optimized using RSM (Kucek et al. 2007;Domingos et al. 2008;Joshi et al. 2008). Please refer to Table 6 for two recent examples from the literature. ...
Biodiesel, defined as the mono-alkyl esters of vegetable oils or animal fats, is an environmentally attractive alternative to conventional petroleum diesel fuel (petrodiesel). Produced by transesterification with a monohydric alcohol, usually methanol, biodiesel has many important technical advantages over petrodiesel, such as inherent lubricity, low toxicity, derivation from a renewable and domestic feedstock, superior flash point and biodegradability, negligible sulfur content, and lower exhaust emissions. Important disadvantages of biodiesel include high feedstock cost, inferior storage and oxidative stability, lower volumetric energy content, inferior low-temperature operability, and in some cases, higher NO
x
exhaust emissions. This review covers the process by which biodiesel is prepared, the types of catalysts that may be used for the production of biodiesel, the influence of free fatty acids on biodiesel production, the use of different monohydric alcohols in the preparation of biodiesel, the influence of biodiesel composition on fuel properties, the influence of blending biodiesel with other fuels on fuel properties, alternative uses for biodiesel, and value-added uses of glycerol, a co-product of biodiesel production. A particular emphasis is placed on alternative feedstocks for biodiesel production. Lastly, future challenges and outlook for biodiesel are discussed.
... This study highlights the significant role of waste cooking oil in promoting circular economy principles, exploring sustainable energy resources, enhancing energy security, creating rural economic opportunities, and reducing greenhouse gas emissions. [19,20]. ...
Biodiesel is an eco-friendly, alternative diesel fuel prepared from domestic renewable resources i.e. mainly produced from vegetable oils and animal fats. It is a renewable energy source that appears to be the perfect answer to the world's energy needs, especially those of Ethiopia. The aim of present study was to evaluate the physicochemical characterization and production of biodiesel from cottonseed oil and waste cooking oil. Transesterification of edible and non-edible oil with methanol in the presence of strong acid or base catalysts is the standard process for creating biodiesel. The percent yield of cottonseed crude oil was found to be 62.98 % upon the extraction from the cotton seeds. After food residues and sediments were removed using chemical coagulation with 2% Al 2 SO 4 as a coagulating agent and gravitational sedimentation, approximately 90.24 percent of the oil was recovered. The physicochemical parameters of oils and its biodiesel were performed and the experimental results such as moisture content (0.32% and 0.27%), specific gravity (0.86-0.9258), viscosity (4.1-65mm 2 /sec), saponification value (56.1-182.3 mg/g), Iodine value (51.74-120.53 mgI 2 /g), Acid value (0.30-0.50 mg/g), free fatty acid content (0.23-1.9%), cetane number (74.6-137.56) and higher heat values (40.87-48.94 MJ/kg) are good agreement with ASTM standards. In conclusion, the result of recent study confirmed that the cottonseed oil and waste cooking oil derived biodiesel is an alternative renewable biofuel for petro-diesel with an eco-friendly.
... The reactions were carried out with an ethanol to oil molar ratio of 12:1 and 0.5% w/w of NaOH in relation to the amount of oil. The experimental conditions were established based on research reports in the literature [26,27], and on previous tests aiming to yield high conversions of alkyl ester. ...
This work describes the use of virtual standards as calibration samples in an innovative multivariate calibration approach for the on-line monitoring of alkyl-esters content during biodiesel production process using a miniature near infrared (NIR) spectrometer. For comparison purposes, a partial least squares (PLS) model was built using synthetic blends prepared in laboratory with different concentrations of oil, glycerol, biodiesel, and ethanol and resulted in a satisfactory predictive ability (root mean square error of prediction, RMSEP, of 1.51% w/w). When compared to conventional methods, calibration with synthetic blends has the advantage of simplifying the experimental procedure and reducing the need for reference analysis. Nevertheless, it still requires the preparation of a considerable number of blends in laboratory. To overcome this limitation, this study proposed an innovative approach where a PLS model was constructed based on virtual standards: representative calibration spectra were created by mathematically mixing spectra from pure components and performing an adjustment using the Piecewise Direct Standardization (PDS) method. This significantly reduced the need for calibration synthetic blends and led to similar results (RMSEP of 1.75% w/w), compared to the previous approach. This work also demonstrates the use of the constructed models to predict the concentration profiles of alkyl-esters during the batch transesterification process.
... Cottonseed biodiesel can be considered a second generation biofuel, because it has not been used in the human food chain. In recent years, there exists many active researches on biodiesel production from CSO which involves studies on CSB production, 7 CSB as fuel for engines, 8,9 CSB production from enzyme catalyzed transesterification where refined cottonseed oil reacted with short-chain primary and secondary alcohols, 10 from solid acid catalysts 11 and CSB production assisted by microwave irradiation or ultrasonic methods. 12,13 In all the aforementioned areas, the knowledge of density of CSO and CSB plays an important role in the development, performance, and behavior analysis in the applications. ...
The cottonseed oil (CSO) extraction and processing areas including biodiesel (CSB) production created the need for density availability over wide ranges of temperature and pressure. In this work, densities of CSO and CSB were measured. The measurement of CSO density under pressure has never been reported in the literature. To address this limitation, this work reports new experimental data of densities of CSO measured at temperatures from 278 to 358 K and pressures from atmospheric up to 30 MPa using a vibrating tube densimeter. The measured densities of CSO were correlated with the Goharshadi–Morsali–Abbaspour equation of state (GMA EoS) with an absolute average relative deviation of 0.02%. The coefficients of GMA EoS for CSO and CSB were used to calculate the thermal expansivity and isothermal compressibility which influence power and fuel injection and they are rarely presented for vegetable oils and biodiesel, especially at high pressures. The group contribution method GCVOL, Halvorsen model, and Zong fragment-based approach were used to evaluate the predictive abilities of CSO density data. Good predictions of oil densities were achieved with Halvorsen model for which absolute deviations are in the range of uncertainty of the measurements.
... Currently, optimal biodiesel production through optimized transesterification processes is attracting continuing interest among researchers [2][3][4][5]. Previous literature has reviewed the use of various feedstocks for biodiesel production [6][7][8][9], biodiesel production process via chemical and enzyme catalyzed transesterification and use of Response Surface Methodology (RSM) as an important optimization tool for biodiesel production [3,[10][11][12][13][14][15][16]. RSM, based on the combination of statistical and mathematical tools, is considered to be a valuable technique for the development, modification and optimization of various processes [17,18]. ...
... As a reactant in biodiesel production ethanol has many advantages over methanol: renewable, low toxic, biodegradable, improved lubricity, higher flash point and less viscosity. So ethyl biodiesel is a really renewable energy [2] .Soybean oil, palm oil, rapeseed oil, cottonseed oil, tallow, waste oil can be used to prepare biodiesel. The kinetics of transesterification by soybean oil, palm oil, rapeseed oil were investigated before [3][4][5][6] . ...
The kinetics of transesterification for biodiesel produced by cottonseed oil and ethanol in catalyst (potassium hydroxide) was investigated. The reaction of transesterification can be described by pseudo second order model for the initial stages of the reaction, followed by zero order reaction. The reaction rate constants for transestentcation of cottonseed oil with ethanol at 40°C, 60°C and 78°C are 0.0996, 0.1126and0.1286 L•mol-1/min-1 respectively, and the activation energy of transesterification is 21.6075kJ/mol．
... La modélisation statistique du rendement en esters éthyliques montre que le facteur qui a le plus d'effet est la concentration en catalyseur C, avec un effet négatif et des interactions significatives à la fois avec le ratio molaire et la température (Equation 1), confirmant les résultats de l'étude de Joshi et al sur l'huile de coton (Joshi et al. 2008) (3,7), qui indique un bon ajustement du modèle, ii) le facteur F reg/res d'une valeur de 25,9, 4 fois supérieur au F 6,16 de Fisher (5,1), qui indique que l'ensemble des facteurs testés sont significatifs, iii) le coefficient de détermination R 2 égal à 0,883, qui indique que le modèle est capable de prédire plus de 88% de la variance totale. Le rendement optimum, d'une valeur de 84%, est obtenu pour un ratio molaire éthanol/huile végétale de 15 :1, une concentration massique en KOH de 0,5% et une température de 35°C. ...
... The effects of the main operating parameters including temperature (T), catalyst loading (C), and the methanol-to-oil molar ratio (M) were studied. The choice of the parameters and their levels was based on the previous experimental studies on the transesterification process (Atapour et al., 2014;Farag et al., 2011;Joshi et al., 2008;Olutoye and Hameed, 2013;Silva et al., 2011). Table 2 shows the parameters and their levels. ...
In this research, transesterification of the waste cooking oil has been studied. Response surface methodology (RSM) based on Box–Behnken design was used to investigate the effects of the main operating parameters, including the methanol to oil molar ratio, catalyst concentration, and reaction temperature, on the biodiesel yield. The results revealed that the catalyst concentration is the most important parameter. The maximum biodiesel yield under the optimized conditions was 99.38 wt. %. Thermogravimetric analysis (TGA) was used for the determination of biodiesel conversion and the results were compared with that of gas chromatography (GC) analysis, showing a very small difference. Furthermore, an empirical quadratic equation has been presented to show the relation between biodiesel conversion and product viscosity.
... Currently, optimal biodiesel production through optimized transesterification processes is attracting continuing interest among researchers [2][3][4][5]. Previous literature has reviewed the use of various feedstocks for biodiesel production [6][7][8][9], biodiesel production process via chemical and enzyme catalyzed transesterification and use of Response Surface Methodology (RSM) as an important optimization tool for biodiesel production [3,[10][11][12][13][14][15][16]. RSM, based on the combination of statistical and mathematical tools, is considered to be a valuable technique for the development, modification and optimization of various processes [17,18]. ...
The current study describes the emphatic use of response surface methodology for the optimized biodiesel production using chemical and enzymatic transesterification of rice bran and sunflower oils. Optimal biodiesel yields were determined to be 65.3 ± 2.0%, 73.4 ± 3.5%, 96.5 ± 1.6%, 89.3 ± 2.0% and 41.7 ± 3.9% for rice bran oil and 65.6 ± 1.2%, 82.1 ± 1.7%, 92.5 ± 2.8%, 72.6 ± 1.6% and 50.4 ± 2.5% for sunflower oil via the transesterification catalyzed by NaOH, KOH and NaOCH 3 ,NOVOZYME-435 and A.n. Lipase, respectively. Based upon analysis of variance (ANOVA) and Response Surface plots significant impact of reaction parameters under study was ascertained. FTIR spectroscopic and HPLC methods were employed for monitoring the transesterification reaction progress while GC-MS analysis was performed to evaluate the compositional analysis of biodiesel. The fuel properties of both the rice bran and sunflower oil based biodiesel were shown to be technically compatible with the ASTM D6751 and EN 14214 OPEN ACCESS Energies 2012, 5 3308 standards. The monitoring of exhaust emission of synthesized biodiesels and their blends revealed a marked reduction in carbon monoxide (CO) and particulate matter (PM) levels, whereas an irregular trend was observed for NO x emissions.
... However, methanol in the synthesis of FAME is not renewable. Recently, ethanol has been used in place of methanol for synthesis of FAAE (Dalla Rosa et al, 2009;Joshi et al, 2008;Hamad et al, 2008) because it is renewable. The product is a fatty acid ethyl ester (FAEE). ...
Recently, the fatty acid ethyl ester has been synthesized in place of fatty acid methyl ester since ethanol has been more renewable. In this research, oleic acid ethyl ester (OAEE) was synthesized using germinated jatropha seeds (Jatropha curcas.L) and rice bran (Oryza sativa) as source of lipase. The objective of the research was to optimize the synthesis conditions using Response Surface Methodology. Factors, such as crude enzyme concentration, molar ratio of oleic acid to ethanol, and the reaction time, were evaluated. The results show that lipase from germinated jatropha seeds had the hydrolitic and esterifi cation activity about 6.73 U/g and 298.07 U/g, respectively. Lipase from rice bran had the hydrolitic and esterifi cation activity about 10.57 U/g and 324.03 U/g, respectively. The optimum conditions of esterifi cation reaction using germinated jatropha seed lipase as biocatalyst were crude enzyme concentration of 0.31 g/ml, molar ratio of oleic acid to ethanol of 1 : 1.81, and reaction time of 50.9 min. The optimum conditions of esterification reaction using rice bran lipase were crude enzyme concentration of 0.29 g/ml, molar ratio of oleic acid to ethanol of 1 : 2.05, and reaction time of 58.61 min. The obtained amounts of OAEE were 810.77 μmole and 626.92 μmole for lipases from rice bran and germinated jatropha seed, respectively.
... Biodiesel (fatty acid methyl esters) is a processed fuel mainly derived from vegetable oils, animal fats and waste oil. It can replace a significant percentage of petroleum diesel in compression ignition diesel engines due to the similarity of its properties to those of petroleum light oil (Joshi et al., 2008;Fukuda et al., 2001). Biodiesel have received considerable attention in recent years as a renewable, non-toxic and biodegradable fuel. ...
The lipase-catalyzed transesterification of rice bran oil and methanol for biodiesel production in hexane was investigated. The effects of different hexane weight ratio, methanol molar ratio, reaction temperature and immobilized lipase dosage on the total conversion were systematically analyzed by response surface methodology (RSM). RSM analysis showed good correspondence between experimental and predicted values. The optimal condition was 4.058 molar ratio of methanol to oil, temperature 42.295°C, 6.86% immobilized lipase and 0.624 hexane based on rice bran oil weight. Moreover, gas chromatography mass spectrometry showed that biodiesel was mainly composed of the methyl esters of hexadecanoic, 9,12-octadecadienoic and 9-octadecadienoic acid. The fourier transform infrared spectrum of biodiesel also showed the characteristic bands of C=O, O-C-O, C=C and –(CH 2)n-.
... Base catalyzed transesterification seems to be the most feasible method of biodiesel production for an average Alabama farmer because of its relative ease and cost. While Joshi et al. (2008) determined that FAEE (fatty acid ethyl ester) may have enhanced low temperature properties in comparison to FAME (fatty acid methyl ester) and that a maximum yield of 98% ester could be obtained at a KOH level of 1.07% wt/wt and ethanol to oil ratio of 20:1, it may not be the most feasible for a farmer. This method may work for a farmer who has access to ethanol, but in Alabama, methanol is incomparably cheaper with comparable results to that of using ethanol. ...
... It contains gossypol, a naturally occurring toxin that protects the cotton plant from insects. The antioxidant properties of this pigment may also potentially translate into a high oxidative stability of the biodiesel and increase its shelf life (15). ...
... He et al. [9] studied the transesterification of cottonseed oil catalyzed by solid acids. For cottonseed oil high in gossypol content and with potassium hydroxide as catalyst, a catalyst concentration of 1.07% with an oil:alcohol molar ratio of 1:20 at 25°C was effective [10]. The kinetics of KOH-catalyzed transesterification of cottonseed oil was investigated [11]. ...
Esters from vegetable oils have attracted a great deal of interest as substitutes for petrodiesel to reduce dependence on imported petroleum and provide a fuel with more benign environmental properties. In this work biodiesel was prepared from cottonseed oil by transesterification with methanol, using sodium hydroxide, potassium hydroxide, sodium methoxide and potassium methoxide as catalysts. A series of experiments were conducted in order to evaluate the effects of reaction variables such as methanol/oil molar ratio (3:1–15:1), catalyst concentration (0.25–1.50%), temperature (25–65 °C), and stirring intensity (180–600 rpm) to achieve the maximum yield and quality. The optimized variables of 6:1 methanol/oil molar ratio (mol/mol), 0.75% sodium methoxide concentration (wt.%), 65 °C reaction temperature, 600 rpm agitation speed and 90 min reaction time offered the maximum methyl ester yield (96.9%). The obtained fatty acid methyl esters (FAME) were analyzed by gas chromatography (GC) and 1H NMR spectroscopy. The fuel properties of cottonseed oil methyl esters (COME), cetane number, kinematic viscosity, oxidative stability, lubricity, cloud point, pour point, cold filter plugging point, flash point, ash content, sulfur content, acid value, copper strip corrosion value, density, higher heating value, methanol content, free and bound glycerol were determined and are discussed in the light of biodiesel standards such as ASTM D6751 and EN 14214.
... The reaction temperature (T) has a significantly negative effect À decreases the yield of the ester phase, hand in hand with a higher concentration of ethyl esters in the glycerol phase. It is better to use a lower temperature than higher, which corresponds with the findings of Encinar et al. [34], Joshi et al. [35] or Silva et al. [33]. The temperature and time of deethanolisation (T deet ) have an effect on the yield and weight of the glycerol phase. ...
... Response surface methodology (RSM) is proved to be very Downloaded by [ supportive technique for process development, modification, and optimization (Raymond and Douglas 2002). Response surface methodology has been used by many researchers for the optimization purposes (Vicente, et al. 1998; Vicente, Martínez, and Aracil 2005; Ghadge and Raheman 2006; Bouaid et al. 2007; Tiwari, Kumar, and Raheman 2007; Chen, Du, and Liu 2008; Domingos, et al. 2008; Joshi, Toler, and Walker 2008; Rashid et al. 2009). Comprehensive comparison was carried out regarding the optimization of reaction parameters involved in transesterification of waste cooking oil through chemical versus enzymatic routes using Response Surface Methodology (RSM). ...
Present study describes optimized production of waste cooking oil biodiesel using chemical and enzymatic transesterification. Maximum waste cooking oil biodiesel yield was 89 % for chemical transesterification catalyzed by NaOCH3 and 95.9% for enzymatic transesterification using NOVOZYME-435. Optimized waste cooking oil biodiesel yield was procured for chemical transesterification when reactions were performed for 90 minutes at 45 °C using 0.75% NaOCH3 and 6:1 methanol to oil molar ratio, whereas, enzymatic transesterification at 32.50°C for 60 hours using 0.75% NOVOZYME-435 and 6:1 methanol : oil molar ratio. When compared the exhaust emission levels from diesel engine exhaust operated on conventional diesel fuel with the Waste Cooking Oil Biodiesel Blends (WCOB), a notable reduction (%) in CO and PM levels was observed for WCOB5, WCOB20, WCOB40, WCOB50, WCOB80 and WCOB100 whereas in case of NOx emissions reduction (%) was observed only in case of WCOB5, WCOB20 and WCOB40 respectively.
... The conversion percentage was calculated using Eq. (1), which was modified from the equation given by Joshi et al. [26]. In this equation, area under the free fatty acid was incorporated to estimate the conversion percentage more accurately. ...
Various sophisticated chromatographic techniques employing gas chromatography (GC) and high performance liquid chromatography (HPLC) were used to quantify biodiesel in terms of conversion percentage of the oil feedstock. These techniques are time consuming. In the present study, a rapid and reproducible technique was developed using high performance thin layer chromatography (HPTLC) for the accurate quantification of the conversion percentage of triglycerides into biodiesel (fatty acid methyl esters/FAME). The oil substrate was transesterified by a conventional process using alkali catalyst. The monoglycerides, diglycerides, unreacted triglycerides, free fatty acid and biodiesel (FAME) product were analyzed by HPTLC. An absorption maximum of the mixture of standard methyl esters was determined to be 203.5nm by spectroscopic scan. The conversion percentage was calculated from the corresponding peak areas of the glycerides and biodiesel product, separated on thin layer chromatography using hexane, ethyl acetate and acetic acid (9:1:0.1) as mobile phase. In terms of reproducibility and precision of data and also the ease and quickness of simultaneous processing, HPTLC based analysis and quantification of biodiesel (FAME) proved to be an alternative to other conventional analytical techniques like GC and HPLC.
... These articles4567 were addressed transesterification by cottonseed oil and methanol. Several studies8910 [13]. The conversion rate of transesterification reached 86% with ethanol /rapeseed oil molar ratio of 5: 1, amount of catalyst of 1 Owt. ...
A new process of biodiesel production by transesterification cottonseed oil with ethanol using tetrahydrofuran (THF)as cosolvent was investigated. The result shows that triglyceides and ethanol could easily dissolve each other with THF in reaction mixture. The order of factors effect on conversion is as follows: molar ratio of ethanol/oil reaction temperature concentration of cosolventreaction timeamount of catalyst. The maximal conversion of 88.73% was observed after 1.5h with ethanol/oil of 141, reaction temperature of 78C, the amount of KOH of 1.25wt% and the ratio of THF/oil of 11.
... The percentage conversion was calculated using Eq. (1) as described by Joshi et al. [26]. ...
The enzymatic production of biodiesel by transesterification of cottonseed oil was studied using low cost crude pancreatic lipase as catalyst in a batch system. The effects of the critical process parameters including water percentage, methanol:oil ratio, enzyme concentration, buffer pH and reaction temperature were determined. Maximum conversion of 75–80% was achieved after 4 h at 37 °C, pH 7.0 and with 1:15 M ratio of oil to methanol, 0.5% (wt of oil) enzyme and water concentration of 5% (wt of oil). Various organic solvents were tested among which a partially polar solvent (t-butanol) was found to be suitable for the reaction. The major fuel characteristics like specific gravity, kinematic viscosity, flash point and calorific value of the 20:80 blends (B20) of the fatty acid methyl esters with petroleum diesel conformed very closely to those of American Society for Testing Materials (ASTM) standards.
Using industrial waste materials in the treatment of problematic soils is an environmentally friendly and cost-effective technique. It helps in decreasing disposal issues induced by various industrial wastes. Also, it is crucial to understand the behavior of these waste products before use. This paper presents experimental research in the treatment of expansive soil by the utilization of iron furnace slag. A laboratory program was performed to examine the effect of iron furnace slag on enhancing the engineering properties of expansive soil. Several tests included liquid limits, plastic limits, free swell percentage, swelling pressure, and unconfined compressive strength were conducted on untreated and treated soils. The efficiency of adding 0, 2, 4, and 6 percentages of iron slag to the soil was investigated. The results of the natural and iron slag stabilized soils showed that iron slag has a notable effect on strength parameters and considerable improvement in plasticity and swelling properties. The addition of iron slag to the soil increased the unconfined compressive strength while reduced the swelling potential of the soil. It is concluded that the utilization of iron slag to improve the properties of expansive soil is successful and useful
Biodiesel is a non-toxic and renewable fuel produced by a transesterification reaction between alcohol and vegetable oil. The objective of this paper is to optimize the ultrasound-assisted production of biodiesel. The central composite design method was used to optimize the transesterification reaction conditions of biodiesel production from peanut oil. The independent variables investigated in the course of the experiment include the catalyst concentration, the reaction time, and the ultrasonic amplitude. The reaction was done by employing ultrasound under set conditions of atmospheric pressure and ambient temperature. A statistical model predicted the optimum conversion yield of peanut biodiesel to be 100.00% under the following optimum experimental conditions: ultrasonic amplitude equals 69.7%, catalyst concentration equals 0.88% weight percent catalyst, and reaction time of 39.38 s. Also, such conditions led to obtaining the linear equation for predicting the conversion yield of biodiesel production.
The performances of the response surface methodology (RSM) in connection with the Box–Behnken, face central composite or full factorial design (BBD, FCCD or FFD, respectively) were compared for the use in modeling of the NaOH-catalyzed sunflower oil ethanolysis. The influence of temperature, catalyst loading, and ethanol-to-oil molar ratio (EOMR) on fatty acid ethyl esters (FAEE) content was evaluated. All three multivariate strategies were efficient in the statistical modeling and optimization of the influential process variables but BBD and FCCD realization involved less number of experiments, generating smaller costs, requiring less work and consuming shorter time than the corresponding FFD. All three designs resulted in the same optimal catalyst loading (1.25% of oil) and EOMR (12:1). The reduced two-factor-interaction (2FI) models based on the BBD and FCCD defined a range of optimal reaction temperature (25 °C–75 °C) and 25 °C, respectively while the same model based on the 3³ FFD appointed 75 °C. The predicted FAEE content of about 97%–98.0% was close to the experimentally obtained FAEE content of about 97.0%–97.6% under the optimal reaction conditions. Therefore, the simpler BBD or FCCD might successfully be applied for statistical modeling of biodiesel production processes instead of the more extensive, more laborious and more expensive FFD.
Biodiesel from waste cooking oil (WCO) requires antioxidants to meet oxidation stability specifications set forth in ASTM D6751 or EN 14214. In contrast, unrefined cottonseed oil (CSO), containing tocopherols and gossypol, produces biodiesel of higher oxidation stability. However, only a portion of these CSO endogenous antioxidants are suspected to be retained in biodiesel. Because the economics of biodiesel manufacturing rely upon inexpensive sources of triglycerides, emphasis was placed on developing improved alternative processing methods where WCO was the main source of methyl esters (WCOME) and CSO was used as a supplemental source of triglycerides and antioxidants in a 4:1 ratio. This study compared four processing methods for their ability to produce biodiesel of increased oxidative stability prepared from a 4:1 ratio of WCO:CSO. Two novel processing methods developed for this study utilise solvent properties of fatty acid methyl esters and glycerol to avoid additional chemical inventory for biodiesel processors. This study concludes that the two new processing methods resulted in biodiesel that had statistically significant improved oxidation stability when compared to two common industrial processing methods. Another significant finding is that high-shear homogenisation during transesterification reduced reaction time from the published one hour to 16 minutes.
Biodiesel from palm oil mill sludge (POMS) was prepared in the presence of novel silica-based heterogeneous catalysts derived from Imperata cylindrica sp. Imperatacid and Imperatabase are two types of heterogeneous catalysts derived from Imperata cylindrica sp and characterized using scanning electron microscopy, Energy Dispersive X-ray, Brunauer-Emmett-Teller surface area and pore size measurement. Imperatacid has particle size of 43.1-83.9 µm while Imperatabase in the range of 89-193 µm. Imperatacid was conveniently applied in esterification step to afford > 90 wt% oil in 1:3 (oil/methanol) and 10 wt% catalyst, followed by transesterification with 1 wt% Imperatabase and 1:1 (oil/methanol) for 1 h at 65°C to afford 80% biodiesel with higher percentage of methyl palmitate (48.97%) and methyl oleate (34.14%) compare to conventional homogeneous catalyst. Reusability of the catalyst up to three times afforded biodiesel ranging from 78-80% w/w. The biodiesel was demonstrated onto alternative diesel engine (Megatech®-Mark III) and showed proportional increased of torque (ɽ) to biodiesel loading.
In this work, the ethanolysis of triglycerides catalyzed by immobilized lipase was studied, focusing on the secondary reaction of acyl migration. The catalytic tests were performed in a solvent-free reaction medium using Novozym 435 as biocatalyst.
The selected experimental variables were biocatalyst loading (5–20 mg), reaction time (30–90 min), and chain length of the fatty acids in triglycerides with and without unsaturation (short (triacetin), medium (tricaprylin) and long (tripalmitin/triolein)).
The formation of 2-monoglyceride by ethanolysis of triglycerides was favored by long reaction times and large biocatalyst loading with saturated short- to medium-chain triglycerides. In the case of long-chain triglycerides, the formation of this monoglyceride was widely limited by acyl migration.
In turn, acyl migration increased the yield of ethyl esters and minimized the content of monoglycerides and diglycerides. Thus, the enzymatic synthesis of biodiesel was favored by long-chain triglycerides (which favor the acyl migration), long reaction times and large biocatalyst loading.
The conversion of acylglycerides made from long-chain fatty acids with unsaturation was relatively low due to limitations in their access to the active site of the lipase.
Vegetable oils provide energy. This is the reason plants tend to pack lipids into their seeds so that the stored energy can be used to support germination. In contrast to animal fats, the lipids stored in the seeds are liquids and are classified as oils or vegetable oils. Several plant species have a remarkable capacity to store large amounts of oils in their seeds, which can be extracted and used in numerous ways. Traditional and historical uses of vegetable oils are wide and varied, including food, lubricants, fuel for paraffin lamps, medicinal and therapeutic uses, spiritual uses, chemical feedstocks, and wood preservatives. With the development of science and technology, uses of vegetable oils expanded, based on their qualities and physical and chemical properties (Walker 2004).
The aim of this paper is to propose a new analytical method for quantification of gossypol in the cottonseed product (glands, raw and refined cottonseed oil and cottonseed feed). This method developed utilizes a liquid chromatography mass spectrometry technique with an ion trap-MS detector. For the positive ionization of this compound an APCI interface was utilized, based on SIM and SRM detection. The method was submitted to a validation procedure evaluating the repeatability and precision data in a natural sample and in a spiked sample. The results obtained for a gossypol natural content of 3.0 mg/kg showed a repeatability value of 1.8 mg/kg with RSDr (%) of 18.6%, while the results obtained for a spiked sample at a level of 2.0 mg/kg of gossypol are: recovery of 88.7% with mean value of 1.8 mg/kg, repeatability value of 0.6 mg/kg with RSD (%) of 9.0%. The technique results to be selective, accurate and specific for the suitable purpose and in agree with the limits present in actual Legislation [1, 2, 3].
Synthetic antioxidants, butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT), are used far less in edible food products, especially vegetable oils, because of serious health and safety concerns. As a result, there is a much greater dependence on natural indigenous antioxidants, particularly tocopherols, for maintaining the shelf life of edible oils. This chapter reviews the natural antioxidants, including tocopherols, in palm, soybean, canola, and low erucic acid rapeseed oil, peanut, olive, sunflower, corn, and cottonseed oils that protect against oxidative rancidity. The potential of other natural antioxidants, such as obtained from rosemary, sage, and thyme, for enhancing the shelf life of edible vegetable oils, is also included.
In this work, we optimize the simultaneous production of biodiesel (FAEE) and ethanol from switchgrass. Two technologies are considered for switchgrass pretreatment, dilute acid and ammonia fibre explosion (AFEX). Next, enzymatic hydrolysis follows any of the pretreaments to obtain fermentable sugars, mainly xylose and glucose. We separate the lignin, and with the sugars, we consider the production of bioethanol and/or FAEE. Based on a superstructure of alternatives, the problem is formulated as an MINLP with simultaneous optimization and heat integration. An economic evaluation is performed and water consumption is calculated. The simultaneous production of bioethanol and FAEE from switchgrass is shown not to be competitive at the current development of the conversion of sugars to FAEE, but it can become promising if the conversion from sugar exceeds 0.5. The optimal solution indicates the bioethanol to be the preferred product due to its higher yield.
Biodiesel is a renewable fuel that is suitable for both stationary and automotive engines. It consists of fatty acid methyl esters and fatty acid ethyl esters when vegetable oils are transesterified with methanol and ethanol respectively. The structural configuration and properties of individual fatty acid methyl esters can significantly influence the biodiesel properties. The purpose of the present work is to review the effects of the properties and the structural configurations of fatty acid methyl esters on various biodiesel properties. The structural configuration includes the molecular structure, the chain length, the saturated or unsaturated nature, the degree of unsaturation and the position of double bonds. Important properties of fatty acid methyl esters are reviewed, and a large number of data consisting of their reported values are given. The viscosity, the cetane number, the heat of combustion, the density, the bulk modulus and compressibility, the iodine value, the oxidative stability, the low-temperature properties, the boiling point, the lubricity, the saponification value, the surface tension, the specific heat, the latent heat of vaporization and the flash point are reviewed in the present study. The reported mathematical equations for estimating the properties of fatty acid compounds and biodiesel are presented. A few studies that recommend enrichment of a particular fatty acid (or acids) which is possible through genetic modification to improve the overall biodiesel properties are also cited. The contribution of a particular fatty acid (or acids) favours some properties while it has an undesirable effect on other properties. Hence the specification of one particular fatty acid profile to improve all the properties of biodiesel is not possible. Considering the low-temperature properties and the oxidative stability, a combination of both saturated fatty acids and unsaturated fatty acids is necessary. Therefore, it is important to decide whether a biodiesel should contain a larger amount of saturated fatty acid esters or unsaturated fatty acid esters in order to obtain better fuel properties. The inherent genetic modification of the fatty acid profile could be the best possibility for addressing several fuel property issues simultaneously.
The production of biodiesel from algae is optimized using bioethanol following four different transesterification paths: alkali, enzymatic, and heterogeneous catalysts and supercritical conditions. The reactors are modeled using response surface methodology based on experimental results from the literature. These reactor models are implemented together with short-cut methods for the other equipment (distillation columns, gravity separators, etc.) in order to recover the ethanol, separate the polar and nonpolar phases, and purify the glycerol and biodiesel produced to formulate the problem as a superstructure of alternatives. The aim is to simultaneously optimize and heat integrate the production of biodiesel using ethanol in terms of the reaction technology and the operating conditions. The optimal conditions in the reactors differ from the ones traditionally used because these results take the separation stages into account. In terms of the optimal process, the alkali catalyzed process is the most profitable, while the enzymatic one is also promising due to the lower consumption of energy and water, although it requires significant enzyme cost. © 2012 American Institute of Chemical Engineers AIChE J, 59: 834–844, 2013
Low quality rice bran with high free fatty acid content was utilized to produce fatty acid ethyl ester (FAEE) via in situ method. The effects of extraction solvent, acid and alkaline catalysts on the yield rate, esterification rate and transesterification rate were studied. About 12% (wFAEE/wrice-bran) of FAEE was obtained when absolute ethanol was used as solvent to extract rice bran oil. The esterification rate and transesterification rate reached 98% and 83%, respectively. With the aid of petroleum ether, the yield rate of FAEE could be improved to 16% (wFAEE/wrice-bran), and the esterification rate and transesterification rate reached 99% and 86%. Hydrophobic CaCO3 nanorods were also synthesized as value-added byproduct. Based on the proposed method, the production process of FAEE could be simplified and the production cost could be reduced.
Transesterification of refined cottonseed oil (CSO) was carried out with methanol, ethanol, 1-butanol, and various mixtures
of these alcohols to produce biodiesel. In the mixed alcohol transesterifications, formation of methyl esters was favored
over ethyl and butyl esters. The influence of ester head group on fuel properties was determined. Specifically, cold flow
properties, lubricity, and energy content improved in the order: CSO butyl esters (CSBE, best) > ethyl esters (CSEE) > methyl
esters (CSME). Higher kinematic viscosities (KVs) as well as lower iodine values (IVs) and wear scars were observed with larger
ester head groups. Blends of CSME, CSEE and CSBE exhibited properties intermediate to the neat esters. All ester samples were
within the limits prescribed in ASTM D6751 and EN 14214 for cetane number, acid value (AV), glycerol (free and total) content,
sulfur, and phosphorous. Also examined was the influence of blending alkyl esters with petrodiesel. All blends exhibited improved
cold flow properties versus unblended alkyl esters. Enhanced lubricity was observed after blending. With increasing content
of biodiesel, higher KVs and lower energy contents were observed. Finally, all blends were within the limits specified in
ASTM D975 and D7467 for AV, KV and sulfur.
Faced with the energy crisis and environmental degradation, due to the massive use of fossil energy sources, biodiesel is an attractive alternative to diesel fuel. With a view to developing local biodiesel production, using bioethanol as a sustainable reactant for biodiesel production, rather than methanol, is leading to increasing interest, notably in emerging countries. Indeed, bioethanol, which is less toxic than methanol, is produced from local and renewable agricultural resources, being more sustainable and providing access to greater energy independence. However, some issues are limiting the process like purification problems, or the presence of water in bioethanol leading to a drop in yield. Although several studies have already been published on ethyl ester production, most of them primarily focus on homogeneous alkaline catalysis, and report various data. Therefore, this paper aims at presenting a review of previous studies on the subject.
The low temperature operability and oxidative stability of cottonseed oil methyl esters (CSME) were improved with four anti-gel additives as well as one antioxidant additive, gossypol. Low temperature operability and oxidative stability of CSME was determined by cloud point (CP), pour point (PP), cold filter plugging point (CFPP), and oxidative stability index (OSI). The most significant reductions in CP, PP, and CFPP in all cases were obtained with Technol®, with the average reduction in temperature found to be 3.9 °C. Gunk®, Heet®, and Howe's® were progressively less effective, as indicated by average reductions in temperature of 3.4, 3.0, and 2.8 °C, respectively. In all cases, the magnitude of CFPP reduction was greater than for PP and especially CP. Addition of gossypol, a polyphenolic aldehyde, resulted in linear improvement in OSI (R2 = 0.9804). The OSI of CSME increased from 5.0 to 8.3 h with gossypol at a concentration of 1000 ppm.
The low-temperature properties of mono-alkyl esters derived from tallow and recycled greases were determined for neat esters
and 20% ester blends in No. 2 low-sulfur diesel fuel. Properties studied included cloud point, pour point, cold filter plugging
point, low-temperature flow test, crystallization onset temperature, and kinematic viscosity. Compositional properties of
the alkyl esters determined included water, residual free fatty acids, and free glycerol content. In general, the secondary
alkyl esters of tallow showed significantly improved cold-temperature properties over the normal tallow alkyl ester derivatives.
The low-temperature flow test did not show a 1:1 correlation with cloud point as previously observed with methyl soyate and
methyl tallowate. For the homologous series methyl to n-butyl tallowate, ethyl tallowate had the best broad-spectrum low-temperature properties, both neat and when blended in diesel
fuel. For the greases studied, both the normal and branched alkyl ester derivatives showed improved properties over corresponding
tallow esters, especially with neat esters.
Several classical catalytic systems for the transesterification reaction have been used to produce FA ethyl esters (FAEE)
from castor and cottonseed oils The effects of the amount and nature of the catalyst, and of the reaction temperature, on
the yields of FAEE were determined. The most efficient transesterification of castor oil was achieved in the presence of methoxide
and acid catalysts, whereas for cottonseed oil, which has a composition that is much more similar to most vegetable oils than
is castor oil, the highest yields of FAEE were obtained following base-catalysed ethanolysis.
The profitability of biodiesel production largely depends on the understanding of all the processes involved, especially the optimal values of the transesterification process parameters. In this work, the concentration level of catalyst, potassium hydroxide (KOH) that gives the optimal yield of biodiesel from tigernut (cyperus esculentus) oil was determined. This value was obtained as 0.9 % weight (in gram) of catalyst per volume of transesterified tigernut oil and it gave a biodiesel yield fraction of 0.67.
The transesterification of vegetable oils with methanol as well as the main uses of the fatty acid methyl esters are reviewed. The general aspects of this process and the applicability of different types of catalysts (acids, alkaline metal hydroxides, alkoxides and carbonates, enzymes and non-ionic bases, such as amines, amidines, guanidines and triamino(imino)phosphoranes) are described. Special attention is given to guanidines, which can be easily heterogenized on organic polymers. However, the anchored catalysts show leaching problems. New strategies to obtain non-leaching guanidine-containing catalysts are proposed. Finally, several applications of fatty acid esters, obtained by transesterification of vegetable oils, are described.
A simple procedure suitable for rapid transmethylation of triacylglycerols, other neutral lipids (including cholesteryl esters), and glycerophospholipids is described. Lipids in diethyl ether solution (50 volumes), in the presence of methyl acetate (1 vol), are reacted with 1 M sodium methoxide in methanol (1 vol) at room temperature. Essentially complete transmethylation can occur within a few minutes with no hydrolysis. Glassware and reagent requirements are minimal and samples are ready for gas-liquid chromatography analysis with very little work-up.
The transesterification of castor oil with ethanol in the presence of sodium ethoxide as catalyst is an exceptional option for the Brazilian biodiesel production, because the castor nut is quite available in the country. Chemically, its oil contains about 90% of ricinoleic acid that gives to the oil some beneficial characteristics such as its alcohol solubility at 30 degrees C. The transesterification variables studied in this work were reaction temperature, catalyst concentration and alcohol oil molar ratio. Through a star configuration experimental design with central points, this study shows that it is possible to achieve the same conversion of esters carrying out the transesterification reaction with a smaller alcohol quantity, and a new methodology was developed to obtain high purity biodiesel.
Fats and oils have been recovered for thousands of years from oil bearing seeds, nuts, beans, fruits, and animal tissues. These raw materials serve a vital function in the United States and world economics for both food and nonfood applications. Edible fats and oils are the raw materials for oils, shortenings, margarines, and other specialty or tailored products that are functional ingredients in food products prepared by food processors, restaurants, and in the home. The major nonfood product uses for fats and oils are soaps, detergents, paints, varnish, animal feeds, resins, plastics, lubricants, fatty acids, and other inedible products. Interestingly, many of the raw materials for industrial purposes are by-products of fats and oils processing for food products; however, some oils are produced exclusively for technical uses due to their special compositions. Castor, linseed, tall, and tung oils are all of vegetable origin and are produced for industrial uses only. The USDA Economic Research Service statistics indicate that, of the 27.472 billion pounds of edible fats and oils used in the year 2000, 76.6% was for food products and 23.4% was for nonfood products [16].
A reversed phase HPLC method using ELSD was developed for the detection and quantification of mono-, di-and triacilglycerols in the synthesis of biodiesel from vegetable oils. The concentrations of these components are the key parameters in monitoring the transesterification reaction by which biodiesel is produced and for assessing biodiesel fuel quality. ELSD sensitivity and linearity was established using mono-, di-and triacylglycerol standards. The method can also be used for detecting and quantifying similar compounds in blended petrodiesel.
A kinetic model for the transesterification of a cotton seed oil with ethanol in the presence of water is proposed. The effect of water content in the reacting mixture on the transesterification reaction is studied. The dependence of the equilibrium constants and reaction rate constants on the water content is presented. Equilibrium was reached within less than 30 min reaction time in all cases. The increase of the water content results in decrease of the conversion level of the oil. By increasing the ethanol/oil ratio the conversion of triglyceride increases and the concentration of mono- and diglyceride in the product mixtures are reduced.
Biodiesel is made by the transesterification of vegetable oils to form alkyl FA esters. High levels of conversion (>99%) are
required to lower the total concentration of free and chemically bound glycerol to that allowed by the ASTM standard (0.240
wt%) for biodiesel. A polar dye was used to visualize the phase behaviors in methanolysis, ethanolysis, and butanolysis. The
dye was more strongly colored in more polar phases. Methanolysis and ethanolysis reactions commenced as two phases (alcohol
and oil), then formed emulsions, and ended as two phases as glycerol-rich phases separated. Ethanolysis was more easily initiated
by mixing than was methanolysis. Ethanolysis also exhibited a much longer emulsion period and slower glycerol separation.
The glycerol-rich phase was smaller in volume in ethanolysis than in methanolysis. Butanolysis remained one phase throughout,
and no polar phase existed at any time. The results are consistent with the known phase compositions in these reactions. The
concentrations of MG, DG, and TG in the products with time in stirred reactions were consistent with the observed phase behavior
in the dye experiments.
Existing HPLC methods determine only pure gossypol whereas the official AOCS method determines both gossypol and other physiologically
active gossypol-like compounds that react with 3-amino-1-propanol and aniline. The feed industry uses the official AOCS method,
which is complex and produces results that do not correlate well among laboratories. HPLC methods were developed, using 3-amino-1-propanol
as a complexing agent, for the quantitative determination of free and total gossypol in cottonseed meal, oil, and ethanolic
miscella. These methods are simple, sensitive, and provide reproducible results. In addition the use of toxic aniline is eliminated.
Transesterification reaction variables that affect yield and purity of the product esters from cottonseed, peanut, soybean
and sunflower oils include molar ratio of alcohol to vegetable oil, type of catalyst (alkaline vs acidic), temperature and
degree of refinement of the vegetable oil. With alkaline catalysts (either sodium hydroxide or methoxide), temperatures of
60 C or higher, molar ratios of at least 6 to 1 and with fully refined oils, conversion to methyl, ethyl and butyl esters
was essentially complete in 1 hr. At moderate temperatures (32 C), vegetable oils were 99% transesterified in ca. 4 hr with
an alkaline catalyst. Transesterification by acid catalysis was much slower than by alkali catalysis. Although the crude oils
could be transesterified, ester yields were reduced because of gums and extraneous material present in the crude oils.
Binding of gossypol by gossypin and congossypin and their succinylated and sulfhydryl group-blocked derivatives has been measured.
The binding by gossypin and congossypin is characterized by weak interaction. Succinylation of gossypin decreases the binding
affinity whereas that of congossypin increases it. Blocking of sulfhydryl groups of both the proteins does not significantly
affect gossypol binding, Succinylation dissociates gossypin and causes conformational changes whereas it does not dissociate
congossypin but causes conformational changes. Sulfhydryl group blocking does not dissociate gossypin or congossypin, nor
does it cause any conformational changes.
Two-phase base-catalyzed transesterification of vegetable oils is the most common method for making biodiesel. The reaction
starts as separate oil and alcohol phases. At the end of the reaction, the mixture, if allowed to settle, consists of an upper
ester-rich layer and a lower glycerol-rich layer. The compositions of these layers from the methanolysis and ethanolysis of
soybean oil were measured. Synthetic mixtures and actual reaction mixtures were used either to represent or generate steadystate
reaction mixtures resulting from the initial condition of 6∶1 alcohol/oil molar ratio and catalyst concentration (1.0 wt%
sodium methoxide or 1.26 wt% sodium ethoxide). At 23°C, for methanolysis, 42.0% of the alcohol, 2.3% of the glycerol, and
5.9% of the catalyst were in the ester-rich phase at steady state. In ethanolysis, 75.4% of the ethanol, 19.3% of the glycerol,
and 7.5% of the catalyst were in the ester-rich phase. The volume of the glycerol-rich phase decreased from methanolysis to
ethanolysis to propanolysis; butanolysis remained monophasic throughout. The results explain some of the general kinetic behavior
observed in transesterifications and provide useful information for alcohol recovery and product purification.
Gossypol, a pigment in cottonseed, is a polyphenolic, binaphthyl dialdehyde. Due to steric hindrance between the functional
groups of the molecule at the bond connecting the two naphthyl rings, gossypol exists as (+)- and (−)-isomers. Gossypol is
physiologically active with the (−)-isomer appearing to be more active and causing temporary infertility in males. It is thus
important to know the amounts of isomers in livestock feeds. A quantitative high-performance liquid chromatography (HPLC)
procedure was developed for the separation of (+)- and (−)-gossypol contained in cottonseed. This method involves derivatization
of gossypol with (R)-(−)-2-amino-1-propanol followed by HPLC separation employing either a Phenomenex Prodigy (5 µ, ODS-3, 100 × 3.2 mm) or a
MetaChem Inertsil (5 µ, ODS-3, 100 × 3.0 mm) reversed-phase column eluted with 80% acetonitrile and 20% 10 mM KH2PO4 adjusted to pH 3.0 with H3PO4 at 1.0 mL/min. The (+)- and (−)-gossypol-2- amino-1-propanol complexes eluted at roughly 1.4 and 2.6 min, respectively. It
was found that gossypol from Upland (Gossypium hirsutum) seed was rich in the (+)-enantiomer, with the (+)- and (−)-enantiomers in a ratio of about 65:35, respectively, while gossypol
from the seed of a Pima (G. barbadense) cultivar (S-6) was slightly richer in the (−)-enantiomer (46.8:53.2).
In this study, the characteristics and performance of three commonly used catalysts used for alkaline-catalyzed transesterification i.e. sodium hydroxide, potassium hydroxide and sodium methoxide, were evaluated using edible Canola oil and used frying oil. The fuel properties of biodiesel produced from these catalysts, such as ester content, kinematic viscosity and acid value, were measured and compared. With intermediate catalytic activity and a much lower cost sodium hydroxide was found to be more superior than the other two catalysts. The process variables that influence the transesterification of triglycerides, such as catalyst concentration, molar ratio of methanol to raw oil, reaction time, reaction temperature, and free fatty acids content of raw oil in the reaction system, were investigated and optimized. This paper also studied the influence of the physical and chemical properties of the feedstock oils on the alkaline-catalyzed transesterification process and determined the optimal transesterification reaction conditions that produce the maximum ester content and yield.
Biodiesel, defined as the mono-alkyl esters of vegetable oils or animal fats, is an “alternative” diesel fuel that is becoming accepted in a steadily growing number of countries around the world. Since the source of biodiesel varies with the location and other sources such as recycled oils are continuously gaining interest, it is important to possess data on how the various fatty acid profiles of the different sources can influence biodiesel fuel properties. The properties of the various individual fatty esters that comprise biodiesel determine the overall fuel properties of the biodiesel fuel. In turn, the properties of the various fatty esters are determined by the structural features of the fatty acid and the alcohol moieties that comprise a fatty ester. Structural features that influence the physical and fuel properties of a fatty ester molecule are chain length, degree of unsaturation, and branching of the chain. Important fuel properties of biodiesel that are influenced by the fatty acid profile and, in turn, by the structural features of the various fatty esters are cetane number and ultimately exhaust emissions, heat of combustion, cold flow, oxidative stability, viscosity, and lubricity.
The production of fatty acid methyl esters, to be used as a diesel substitute (biodiesel), has been studied. The reaction of refined sunflower oil and methanol was carried out over different types (acid and basic, homogeneous and heterogeneous) of catalysts. The catalyst that led to largest conversions was sodium hydroxide. No methyl esters were detected when zirconium-based catalysts and an immobilized lipase were used. The process of biodiesel production was optimized by application of the factorial design and response surface methodology. Temperature and catalyst concentration were found to have a positive influence on conversion, concentration effect being larger than temperature effect. A second-order model was obtained to predict conversions as a function of temperature and catalyst concentration. Optimum conditions for the production of methyl esters were found to be mild temperatures (20–50°C) and large catalyst concentrations (1.3%).
Dependence of biodiesel fuel properties on the structure of fatty acid alkyl esters ASTM D 6751-07b (2007) Standard specification for biodiesel fuel blend stock (B100) for middle distillate fuels
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ASTM D 6751-07b (2007) Standard specification for biodiesel fuel blend stock (B100) for middle distillate fuels, American Society for Testing and Materials, West Conshohocken, PA 5. EN 14214-2003 (2003) Automotive fuels—fatty acid methyl esters (FAME) for diesel engines—requirement methods, Euro-pean Committee for Standardization, Brussels, Belgium
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