Effects of water on the esterification of free fatty acids by acid catalysts

To maximize the production of biodiesel from soybean soapstock, the effects of water on the esterification of high-FFA (free fatty acid) oils were investigated. Oleic acid and high acid acid oil (HAAO) were esterified by reaction with methanol in the presence of Amberlyst-15 as a heterogeneous catalyst or sulfuric acid as a homogeneous catalyst. The yield of fatty acid methyl ester (FAME) was studied at oil to methanol molar ratios of 1:3 and 1:6 and reaction temperatures of 60 and 80 °C. The rate of esterification of oleic acid significantly decreased as the initial water content increased to 20% of the oil. The activity of Amberlyst-15 decreased more rapidly than that of sulfuric acid, due to the direct poisoning of acid sites by water. Esterification using sulfuric acid was not affected by water until there was a 5% water addition at a 1:6 molar ratio of oil to methanol. FAME content of HAAO prepared from soapstock rapidly increased for the first 30 min of esterification. Following the 30-min mark, the rate of FAME production decreased significantly due to the accumulation of water. When methanol and Amberlyst-15 were removed from the HAAO after 30 min of esterification and fresh methanol and a catalyst were added, the time required to reach 85% FAME content was reduced from 6 h to 1.8 h.     

Efficient preparation of biodiesel from rapeseed oil over modified CaO

In this study, the catalytic performance of commercial CaO modified by trimethylchlorosilane (TMCS) for transesterification of rapeseed oil and methanol to biodiesel production was investigated. It was found that the fatty acid methyl esters (FAME) yield of the modified CaO was greatly enhanced from 85.4% to 94.6%. The possible reason lies on promoting the absorption of grease to CaO surface. Good results of repeated experiments showed that the modified catalyst has the capacity of water resistance and can be reused for several runs without significant deactivation, which can be confirmed by the humidity test in the vapor-saturated atmosphere. Both the characterizations of the catalyst and the effects of various factors such as mass ratio of catalyst to oil, reaction temperature and molar ratio of methanol to oil were investigated.     

Synthesis of glycerol-free fatty acid methyl ester using interesterification reaction based on solid acid carbon catalyst derived from low-cost biomass wastes

The current research was aimed to corroborate as well as compare the feasible applicability of waste banana peel and empty fruit bunch (EFB) in synthesising high-performing heterogeneous catalysts. The solid acid catalysts originated from biomass wastes were employed for the synthesis of glycerol-free fatty acid methyl ester (FAME) using catalytic interesterification process pathway. Acetic acid was produced as the by-product instead of glycerol. The heterogeneous acid catalysts were synthesised utilising sulphuric acid through direct sulfonation with thermal treatment. The concentration of the sulphuric acid was manipulated from 2 to 13 mol L^?1 to investigate its effects on the resulting FAME yield while maintaining the sulfonating ratio at 10 mL g^?1. The catalytic performances of the as-synthesised catalysts were studied under reaction conditions of 12 wt % catalyst loading, 50:1 methyl acetate to oleic acid molar ratio for a duration of 8 hours at 60°C. The catalyst produced by activated carbon derived from EFB and sulfonated with 13 mol L^?1 sulphuric acid exhibited the highest FAME yield at 44.3%. The parameter studies on reactant ratio (45:1-70:1), reaction temperature (90°C-130°C) and time (4-24 hours) of interesterification reaction discovered a general increasing trend in the FAME yield up to 52.3% with the optimum conditions of 50:1, 110°C and 8 hours, respectively. The catalyst was recyclable with 82% of the catalytic performance retained after five successive cycles with catalyst reactivation. This study confirmed that the renewable heterogeneous catalyst derived from biomass waste could catalyse the glycerol-free interesterification process via an environmentally benign and promising approach for green fuel production.     

Biodiesel production from oil-rich feedstock: A neural network modeling

Biodiesel produced from oil-rich feedstocks is known as a green replacement for conventional petroleum diesel. Transesterification is the common method used for biodiesel production. Hence, in this contribution, neural network modeling and least square support vector machine (LSSVM) modeling were used to predict the transesterification of castor oil with methanol to form biodiesel. Also, genetic algorithm was used for the optimization of predictive model. Input and output parameter of predictive models for the prediction of biodiesel production yield and estimation of the efficiency of biodiesel production are catalyst weight (C), methanol-to-oil molar ratio (MOR), time (S), temperature (T), and fatty acid methyl ester (FAME) yield, respectively. Proposed LSSVM modeling predicts biodiesel production yield or FAME yield within ±2% relative deviation with a high value of coefficient of determination (0.99583) and a low value of absolute deviation (1.27) in which the mentioned statistical parameters represent the accuracy and robustness of the model.     

Production of FAME by palm oil transesterification via supercritical methanol technology

The present study employed non-catalytic supercritical methanol technology to produce biodiesel from palm oil. The research was carried out in a batch-type tube reactor and heated beyond supercritical temperature and pressure of methanol, which are at 239 °C and 8.1 MPa respectively. The effects of temperature, reaction time and molar ratio of methanol to palm oil on the yield of fatty acid methyl esters (FAME) or biodiesel were investigated. The results obtained showed that non-catalytic supercritical methanol technology only required a mere 20 min reaction time to produce more than 70% yield of FAME. Compared to conventional catalytic methods, which required at least 1 h reaction time to obtain similar yield, supercritical methanol technology has been shown to be superior in terms of time and energy consumption. Apart from the shorter reaction time, it was found that separation and purification of the products were simpler since no catalyst is involved in the process. Hence, formation of side products such as soap in catalytic reactions does not occur in the supercritical methanol method.     

Optimization of transesterification conditions for the production of fatty acid methyl ester (FAME) from Chinese tallow kernel oil with surfactant-coated lipase

Surfactant-coated lipase was used as a catalyst in preparing fatty acid methyl ester (FAME) from Chinese tallow kernel oil from Sapium sebiferum (L.) Roxb. syn. Triadica sebifera (L.) small. FAME transesterification was analyzed using response surface methodology to find out the effect of the process variables on the esterification rate and to establish prediction models. Reaction temperature and time were found to be the main factors affecting the esterification rate with the presence of surfactant-coated lipase. Developed prediction models satisfactorily described the esterification rate as a function of reaction temperature, time, dosage of surfactant-coated lipase, ratio of methanol to oil, and water content. The FAME mainly contained fatty acid esters of C16:0, C18:0, C18:1, C18:2, and C18:3, determined by a gas chromatograph. The optimal esterification rate was 93.86%. The optimal conditions for the above esterification ratio were found to be a reaction time of 9.2 h, a reaction temperature of 49 °C, dosage of surfactant-coated lipase of 18.5%, a ratio of methanol to oil of 3:1, and water content of 15.6%. Thus, by using the central composite design, it is possible to determine accurate values of the transesterification parameters where maximum production of FAME occurs using the surfactant-coated lipase as a transesterification catalyst.     

A facile noncatalytic methyl ester production from waste chicken tallow using single step subcritical methanol: Optimization study

In this modern era, an increase in urbanization causes the escalating trend of fuel demand as well as environmental pollution problems. Various biofuels research with the respect of climate change and emission reduction recently intensifies, particularly in biodiesel. In Indonesia, diesel oil currently in use contains 20% of biodiesel. Utilizing waste‐based resources such as rendered chicken tallow as the feedstock could be the solution to both energy and environmental challenges. However, chicken tallow contains a significant amount of free fatty acid (FFA) which will obstruct the production yield of biodiesel. In this study, catalyst‐free subcritical methanol has been employed to convert waste chicken tallow (WCT) with high FFA into biodiesel. Design of experiment was conducted to study the effect of temperature, time, and the molar ratio of methanol to fats on the purity and recovery of fatty acid methyl esters (FAMEs). Based on the optimization study performed by response surface methodology (RSM), all three independent variables gave a significant effect on the recovery of FAME. From the experimental results, the maximum FAME yield obtained was 98.43 ± 0.22% with the optimum condition as follows: 167°C, 36.8 minutes, and 42.7:1 (methanol/WCT, mol/mol), while the predicted FAME yield obtained using RSM was 97.76%. The methyl ester composition of WCT‐based biodiesel ranges from C13 to C24.     

Optimization of biodiesel production from camelina oil using orthogonal experiment

Camelina oil is a low-cost feedstock for biodiesel production that has received a great deal of attention in recent years. This paper describes an optimization study on the production of biodiesel from camelina seed oil using alkaline transesterification. The optimization was based on sixteen well-planned orthogonal experiments (OA₁₆ matrix). Four main process conditions in the transesterification reaction for obtaining the maximum biodiesel production yield (i.e. methanol quantity, reaction time, reaction temperature and catalyst concentration) were investigated. It was found that the order of significant factors for biodiesel production is catalyst concentration > reaction time > reaction temperature > methanol to oil ratio. Based on the results of the range analysis and analysis of variance (ANOVA), the maximum biodiesel yield was found at a molar ratio of methanol to oil of 8:1, a reaction time of 70 min, a reaction temperature of 50 °C, and a catalyst concentration of 1 wt.%. The product and FAME yields of biodiesel under optimal conditions reached 95.8% and 98.4%, respectively. The properties of the optimized biodiesel, including density, kinematic viscosity, acid value, etc., were determined and compared with those produced from other oil feedstocks. The optimized biodiesel from camelina oil meets the relevant ASTM D6571 and EN 14214 biodiesel standards and can be used as a qualified fuel for diesel engines.     

Free lipase-catalyzed biodiesel production from phospholipids-containing oils

Free lipase-catalyzed biodiesel has drawn more and more attentions in recent years because of its advantages of lower cost and faster reaction rate. Utilizing free lipase to convert low quality oils such as crude vegetable oils and microbial oils is beneficial to further reduce the cost of biodiesel production. However, these oils typically contain some amount of phospholipids. Phospholipids were found to affect the lipase-catalyzed process and further influence the enzyme's thermal stability in biodiesel production process. In this work, free lipase NS81006-mediated biodiesel production from oils containing phospholipids at varied temperature was investigated systematically. It was found that the presence of phospholipids at high temperature led to a decreased fatty acid methyl esters (FAME) yield and poor reuse stability of the lipase during NS81006-catalyzed biodiesel production process. The higher the temperature was, the greater negative effect was observed. This inhibitory effect was found to be mainly caused by the coexistence of phospholipids and methanol in the system. Based on this finding, a novel two-step enzyme-mediated process was further developed, with which the above-mentioned inhibitory effect was eliminated, and a FAME yield of 95.1% could be obtained with oils containing 10% phospholipids even at high temperature of 55 °C.     

Dimethyl carbonate mediated production of biodiesel at different reaction temperatures

Methanol was replaced by dimethyl carbonate for biodiesel production. In the process, fatty acid methyl ester (FAME) was produced through transesterification of soybean oil with dimethyl carbonate (DMC) using potassium methoxide as a catalyst. This method produced a more attractive by-product, glycerol carbonate (GC). Factors affecting the reaction such as vegetable oil to DMC molar ratio, catalyst concentration, reaction time and reaction temperature were optimized. Triglyceride conversion of 95.8% was obtained at the optimized condition. This process provided an insight into the reactivity of DMC at different temperature. Co-production of FAME and glycerol carbonate (GC) proceeded through carboxymethylation reaction because methoxyl group and carbonyl group are generated which subsequently attacked the carbonyl moiety in glyceride molecules to form the required products.     

Synthesis of fatty acid methyl esters via the methanolysis of palm oil over Ca3.5xZr0.5yAlxO3 mixed oxide catalyst

Novel mixed metal oxide catalyst Ca_3.5xZr_0.5yAl_xO₃ was synthesized through the coprecipitation of metal hydroxides. The textural, morphological, and surface properties of the synthesized catalysts were characterized via Brunauer–Emmett–Teller method, X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, and energy-dispersive X-ray spectroscopy. The catalytic performance of the as-synthesized catalyst series was evaluated during the transesterification of cooking palm oil with methanol to produce fatty acid methyl esters (FAME). The influence of different parameters, including the calcination temperature (300–700 °C), methanol to oil molar ratio (6:1–25:1), catalyst amount (0.5–6.5 wt%), reaction time (0.5–12 h) and temperature (70–180 °C), on the process was thoroughly investigated. The metal oxide composite catalyst with a Ca:Zr ratio of 7:1 showed good catalytic activity toward methyl esters. Over 87% of FAME content was obtained when the methanol to oil molar ratio was 12:1, reaction temperature 150 °C, reaction time 5 h and 2.5 wt% of catalyst loading. The catalyst could also be reused for over four cycles.     

Biodiesel production from mixed soybean oil and rapeseed oil

The biodiesel (fatty acid methyl esters, FAME) was prepared by transesterification of the mixed oil (soybean oil and rapeseed oil) with sodium hydroxide (NaOH) as catalyst. The effects of mole ratio of methanol to oil, reaction temperature, catalyst amount and reaction time on the yield were studied. In order to decrease the operational temperature, a co-solvent (hexane) was added into the reactants and the conversion efficiency of the reaction was improved. The optimal reaction conditions were obtained by this experiment: methanol/oil mole ratio 5.0:1, reaction temperature 55 °C, catalyst amount 0.8 wt.% and reaction time 2.0 h. Under the optimum conditions, a 94% yield of methyl esters was reached ∼94%. The structure of the biodiesel was characterized by FT-IR spectroscopy. The sulfur content of biodiesel was determined by Inductively Coupled Plasma emission spectrometer (ICP), and the satisfied result was obtained. The properties of obtained biodiesel from mixed oil are close to commercial diesel fuel and is rated as a realistic fuel as an alternative to diesel. Production of biodiesel has positive impact on the utilization of agricultural and forestry products.     

Optimization of wet microalgal FAME production from Nannochloropsis sp. under the synergistic microwave and ultrasound effect

The synergistic effect of microwave and ultrasound irradiations was evaluated for biodiesel production from microalgae biomass (Nannochloropsis sp.) as raw material. A response surface methodology technique based on central composite design was used to understand the process parametric interdependence and optimize the process reaction variables. Reaction kinetics of algal fatty acid methyl ester (FAME) production was also studied. The optimum reaction conditions were determined as wet algal biomass to methanol ratio of 20 g to 30 mL, 1 wt% catalyst concentration, and 7‐minute reaction time at 140 W of microwave power and 140 W of ultrasound power. The estimated activation energy was 17,298 J/mol^?1 K^?1 for a first‐order reaction kinetics. This study revealed that microwave energy dissipation at a low rate of 140 W combined with 140 W of ultrasound intensity is adequate to produce FAMEs at a maximum yield of 48.2%. Results from this optimization study suggest that a more detailed and mechanistic energy optimization study is critical to increase the FAME yield and maximize energy benefits.     

Biodiesel production by transesterification of duck tallow with methanol on alkali catalysts

Duck tallow was employed as a feedstock for the production of biodiesel by transesterification with methanol. The content of fatty acid methyl ester (FAME) was evaluated on various alkali catalysts during transesterification. The composition and chemical properties of the FAME were investigated in the raw duck tallow and the biodiesel products. The major constituent in the biodiesel product was oleic acid. The FAME content was 97% on KOH catalyst in the reaction. It was acceptable for the limit of European biodiesel qualities for BD100. Acid value, density, and kinematic viscosity of the biodiesel products also came up to the biodiesel qualities.     

正交试验探讨脂肪酸超临界酯化制备生物柴油

探讨脂肪酸在超临界甲醇中酯化反应的规律及最佳条件。以橡胶籽油脂肪酸为原料,在间歇式高温高压反应釜中通过酯化反应制备生物柴油,分别考察了酯化反应条件如反应温度、反应时间、甲醇与脂肪酸的体积比对酯化率的影响。应用正交试验方法得出酯化反应的较适宜条件为：反应温度290℃,反应时间30min,甲醇与脂肪酸的体积比为4：1。在此反应条件下转化率可达99．2％。橡胶籽油生物柴油成分主要有亚油酸甲酯、油酸甲酯、亚麻酸甲酯,还有少量的硬脂酸甲酯、棕榈酸甲酯。     

Response surface analysis for optimisation of reaction parameters of biodiesel production from alcoholysis of Parinari polyandra seed oil

Availability of information on the efficiency of applied conditions to biodiesel synthesis from diverse seed oil can establish optimal biodiesel yield from favourable reaction variables. The effect of reaction parameters; temperature, time and catalyst amount, were varied on biodiesel yield from alcoholysis of Parinari polyandra oil using potassium hydroxide as catalyst. Maximum biodiesel yield of 95.62% was obtained from the experimental results. Analysis of Variance revealed that the reaction variables had significant effects on biodiesel yield. Data analysis predicted an optimal biodiesel yield of 92.75% at reaction conditions of 61.20°C temperature, 60 min, and 1?wt% of catalyst amount. Validation experiments of the optimal conditions gave an average biodiesel yield of 91.72%. The study established optimal conditions of temperature, time, and catalyst amount for biodiesel production from P. polyandra oil. The fuel properties of the biodiesel fell within the standards of the American Society for Testing and Materials D6751.     

催化合成生物柴油的双金属络合物固体催化剂

制备了基于亚铁氰化锌的双金属氰化物络合物(DMC),可一步同时催化酯交换和酯化反应制备生物柴油,该催化剂体系具有不受水毒性影响的特点。用3wt%的DMC催化剂在433K,醇油摩尔比为16∶1以及水和脂肪酸含量各10wt%的条件下分别同时催化甘油三酯、脂肪酸和甲醇的酯交换、酯化反应,生物柴油产率可达98%以上。对催化剂进行X射线衍射、热重红外联用分析、元素分析、比表面积和孔体积测定、扫描电镜等手段表征,结果表明:该催化剂为晶态与非晶态组分混合结构,其表面晶态决定其在高水含量、高酸值的环境下仍具有较好的催化活性,验证得出活性位点可能为锌离子。     

Study on the use of MgAl hydrotalcites as solid heterogeneous catalysts for biodiesel production

This paper, reports experimental work on the use of new heterogeneous solid basic catalysts for biodiesel production: double oxides of Mg and Al, produced by calcination, at high temperature, of MgAl lamellar structures, the hydrotalcites (HT). The most suitable catalyst system studied are hydrotalcite Mg:Al 2:1 calcinated at 507 °C and 700 °C, leading to higher values of FAME also in the second reaction stage. One of the prepared catalysts resulted in 97.1% Fatty acids methyl esters (FAME) in the 1st reaction step, 92.2% FAME in the 2nd reaction step and 34% FAME in the 3rd reaction step. The biodiesel obtained in the transesterification reaction showed composition and quality parameters within the limits specified by the European Standard EN 14214. 2.5% wt catalyst/oil and a molar ratio methanol:oil of 9:1 or 12:1 at 60–65 °C and 4 h of reaction time are the best operating conditions achieved in this study. This study showed the potential of Mg/Al hydrotalcites as heterogeneous catalysts for biodiesel production.     

Synthesis,characterization, and optimization of Schizochytrium biodiesel production using Na+‐doped nanohydroxyapatite

The present work investigates the synthesis of a new and highly efficient sodium‐doped nanohydroxyapatite, as a heterogeneous catalyst for the production of fatty acid methyl esters from Schizochytrium algae oil. Sodium nitrate supported on nanohydroxyapatite catalyst was prepared using wet impregnation technique and calcinated at different temperatures. The synthesized nanocatalyst was characterized to determine the structural and morphological properties, using BET, XRD, TGA, FTIR, ICP, and TEM. Characterization results reported that the catalyst calcinated at 900°C exhibits good catalytic property. The catalyst was utilized for the production of biodiesel, under different reaction parameters through transesterification process. Response surface methodology (RSM) and artificial neural network (ANN) were employed to evaluate the best combination of molar ratio, catalyst concentration, and reaction time for transesterification process. By using point prediction method, the optimum yield of 96% was achieved at the catalyst concentration of 9.5 wt% of oil, 1:12 molar ratio, and 121‐minute reaction time. The physiochemical properties of the biodiesel were determined, and the result suggested that the biodiesel produced met ASTM D6751 standard. The catalyst exhibits good catalytic performance on reusability up to six runs without the loss of molecular activity. Therefore, the synthesized heterogeneous catalyst derived from animal bone could be efficiently used for the biodiesel production.     

Optimization of biodiesel production from waste cooking oil using waste bone as a catalyst

This work determined the association between several parameters of biodiesel production from waste cooking oil (WCO) using waste bovine bone (WBB) as catalyst to achieve a high conversion to fatty acid methyl ester (%FAME). The effect of three independent variables was used as the optimum condition using response surface methodology (RSM) for maximizing the %FAME. The RSM analysis showed that the ratio of MeOH to oil (mol/mol), catalyst amount (%wt), and time of reaction have the maximum effects on the transform to FAME. Moreover, the coefficient of determination (R²) for regression equations was 99.19%. Probability value (P < 0.05) demonstrated a very good significance for the regression model. The optimal values of variables were MeOH/WCO ratio of 15.49:1 mol/mol, weight of catalyst as 6.42 wt%, and reaction time of 128.67 min. Under the optimum conditions, %FAME reached 97.59%. RSM was confirmed to sufficiently describe the range of the transesterification parameters studied and provide a statistically accurate estimate of the best transform to FAME using WBB as the catalyst.