A rapid ultrasound-assisted production of biodiesel from a mixture of Karanj and soybean oil

Karanj oil having high free fatty acid was neutralized with a dilute alkali solution and then mixed with soybean oil in different ratios in order to reduce the free fatty acid content significantly. The mixture of the oils was then transesterified with methanol to produce fatty acid methyl ester. The transesterification was carried out using ultrasonication energy of 20 kHz in pulse mode. It was found that up to 60% Karanj oil in the blended mixture could produce good quality biodiesel that met the ASTM standards. However, the lesser content of Karanj oil in the mixture, the lesser the reaction parameters viz. alcohol to oil molar ratio, catalyst concentration, and reaction time. About 99% yield of methyl esters was obtained when the Karanj oil content in the mixture was 20% with a reaction time of 30 min, catalyst concentration 1 wt%, and a temperature of 55°C.     

Thermodynamic analysis of fatty acid esterification for fatty acid alkyl esters production

The development of renewable energy source alternatives has become a planet need because of the unavoidable fossil fuel scarcity and for that reason biodiesel production has attracted growing interest over the last decade. The reaction yield for obtaining fatty acid alkyl esters varies significantly according to the operating conditions such as temperature and the feed reactants ratio and thus investigation of the thermodynamics involved in such reactional systems may afford important knowledge on the effects of process variables on biodiesel production. The present work reports a thermodynamic analysis of fatty acid esterification reaction at low pressure. For this purpose, Gibbs free energy minimization was employed with UNIFAC and modified Wilson thermodynamic models through a nonlinear programming model implementation. The methodology employed is shown to reproduce the most relevant investigations involving experimental studies and thermodynamic analysis.     

Potential of waste palm cooking oil for catalyst-free biodiesel production

Disposal of waste palm cooking oil (WPCO) via an environmental-friendly route is of major importance in the quest for sustainable development. In this study, WPCO was utilized instead of refined vegetable oils as the source of triglycerides for biodiesel production. WPCO contains several impurities, such as water and free fatty acids, which limit its application in catalytic transesterification processes. Consequently, a catalyst-free process using supercritical methanol was employed to investigate the potential of WPCO as an economical feedstock for biodiesel production. The parameters that influence the reaction, including reaction time, temperature and the molar ratio of alcohol to oil, were investigated. For comparison purposes, refined palm oil (RPO) was also subjected to supercritical methanol reaction and it was found that both processes produced comparable optimum yields of 80% at their respective optimum conditions. Hence, it can be concluded that WPCO has high potential as an economical and practical future source of biodiesel.     

以棉籽油皂脚为原料制备生物柴油

文章探讨了在酸性催化剂作用下以酸化的棉籽油皂脚为原料制备生物柴油的工艺,为棉籽油生产过程中产生的废料--棉籽油皂脚的回收利用开辟了一条新的途径.试验考察了催化剂用量、反应时间、投料比等因素对反应收率的影响,并通过正交试验优化得到了最佳工艺条件:催化剂(浓硫酸)用量4%(以脂肪物质量计),反应时间10 h,脂肪物与甲醇物质的量比为1:10.在上述最优条件下产品收率可达83%.     

Production of biodiesel from high free fatty acid Karanja (Pongamia pinnata) oil

Non-edible oil contains several unsaponifiable and toxic components, which make them unsuitable for human consumption. Karanja (Pongamia pinnata) is an underutilized plant which is grown in many parts of India. Sometimes the oil is contaminated with high free fatty acids (FFAs) depending upon the moisture content in the seed during collection as well as oil expression. The present study deals with production of biodiesel from high FFA Karanja oil because the conventional alkali-catalyzed route is not the feasible route. This paper discusses the mechanism of a dual process adopted for the production of biodiesel from Karanja oil containing FFA up to 20%. The first step is acid-catalyzed esterification by using 0.5% H₂SO₄, alcohol 6:1 molar ratio with respect to the high FFA Karanja oil to produce methyl ester by lowering the acid value, and the next step is alkali-catalyzed transesterification. The yield of biodiesel from high FFA Karanja oil by dual step process has been observed to be 96.6–97%.     

Fuel properties of blend and biodiesel generated from acid oil using whole cell biocatalyst

Biodiesel was generated through whole cell catalyzed transesterification of acid oil, to the extent of up to 92%. The fuel properties of biodiesel (B100) and its blend (B20) were determined and compared with standard biodiesel as per American Society for Testing and Materials (ASTM) standard (ASTM D6751). B100 and B20 showed good pour point of ?26°C and ?29°C, respectively, indicating their operation viability in colder environment. Other properties of biodiesel are quite similar to petroleum diesel and ASTM standard. The results of this study reveal the potential use of acid oil as feedstock for generation of fuel grade biodiesel through biocatalyzed transesterification.     

Pressurized ultrasonic production of biodiesel from Jatropha oil: optimization and energy analysis

The present study deals with the development of a biodiesel production reactor based on pressurized ultrasonic cavitation technique. Transesterification of Jatropha oil takes place by passing low-frequency ultrasonic irradiation in the reaction mixture flowing at pressurized conditions in the sonochemical reactor. Reaction variables such as reaction time, molar ratio, catalyst concentration, and pressure of the reaction mixture were investigated to find the optimal parameters for biodiesel production. The energy requirement decreases with increase in pressure. Very low value of Specific Energy Consumption (0.018 kWh/kg) and significantly high value of Energy Use Index (598.83) are obtained when the pressure of reaction mixture is 15 bar. Increasing the pressure thereafter, leads to nominal gains. Ultrasonic irradiation at high-pressure condition has an additional advantage of rapid reaction and lower requirement of alcohol to oil molar ratio and catalyst concentration. Fifteen bar pressure is optimal for biodiesel production.     

Homogeneous borotungstic acid and heterogeneous micellar borotungstic acid catalysts for biodiesel production by esterification of free fatty acid

A highly negatively charged borotungstic acid H₅BW₁₂O₄₀ had been tested as homogeneous catalyst in esterification. Compared with common used H₃PW₁₂O₄₀, it displayed a higher conversion (98.7%) and excellent efficiency (96.2%) due to its high amount of protons in methanol. In order to overcome the drawbacks of homogeneous heteropolyacid H₅BW₁₂O₄₀, a Brønsted-surfactant-combined (C₁₆TA)H₄BW₁₂O₄₀ (C₁₆TA = cetyltrimethyl ammonium) had been fabricated with strong acidity and nano-size micellar structure resulting in enhanced activity and stability during the reaction, which exhibited consistent activity during recycling in esterification reaction.     

Biodiesel production from mahua (Madhuca indica) oil having high free fatty acids

A technique to produce biodiesel from mahua oil (Madhuca indica) having high free fatty acids (19% FFA) has been developed. The high FFA level of mahua oil was reduced to less than 1% by a two-step pretreatment process. Each step was carried out with 0.30–0.35 v/v methanol-to-oil ratio in the presence of 1% v/v H₂SO₄ as an acid catalyst in 1-hour reaction at 60°C. After the reaction, the mixture was allowed to settle for an hour and methanol–water mixture that separated at the top was removed. The second step product at the bottom was transesterified using 0.25 v/v methanol and 0.7% w/v KOH as alkaline catalyst to produce biodiesel. The fuel properties of mahua biodiesel were found to be comparable to those of diesel and conforming to both the American and European standards.     

氨基磺酸非均相催化菜籽油及废油脂制备生物柴油

采用正交试验和单因素试验的方法研究了氨基磺酸催化菜籽油及废油脂与甲醇的酯交换过程,考察了醇油物质的量比、催化剂用量、反应温度和反应时间对反应收率的影响。结果表明:菜籽油酯交换的最佳反应条件为醇油物质的量比6∶1,氨基磺酸用量为原料油质量的1.0%,反应温度60℃,反应时间20 min,此工艺条件下,脂肪酸甲酯的收率达到95.6%;废油脂酯交换的最佳反应条件为醇油物质的量比8∶1,氨基磺酸用量为原料油质量的1.0%、反应温度65℃,反应时间30 min,此工艺条件下,脂肪酸甲酯的收率达到87.5%。利用红外光谱表征了菜籽油和生物柴油的结构,气相色谱分析了生物柴油的组成。     

Crystallization behavior of fatty acid methyl esters and biodiesel based on differential scanning calorimetry and thermodynamic model

Biodiesel is mainly composed of methyl palmitate (MeC16), methyl stearate (MeC18), and methyl oleate (MeC18:1). In order to explore the crystallization behavior of biodiesel, the thermal parameters of the three fatty acid methyl esters, their binary mixtures, and biodiesel have been analyzed based on the differential scanning calorimeter. Supposing that biodiesel is a complex solution of various fatty acid methyl esters, the saturated fatty acid methyl esters MeC16 and MeC18 are treated as solutes and the unsaturated fatty acid methyl ester MeC18:1 is served as the solvent; thus a thermodynamic model according to the solid–liquid equilibria for predicting the crystallization onset temperature has been established. As a result, the model is effectively verified when the estimated crystallization onset temperatures for four types of actual biodiesel are compared with the experimental results.     

Production of biodiesel from Citrus limetta seed oil

The production of biodiesel from edible oils may cause negative impact to any country through food crisis which may lead to economic imbalance. Hence, this study focuses on viability of extracting the oil from the Citrus limetta seeds for biodiesel production for the first time. Composition of C. limetta oil was determined by gas chromatography. C. limetta biodiesel was produced by simple transesterification process, and further physiochemical properties were analyzed as per the standards. This study also describes the suitable characterization and optimization parameters used for conversion of C. limetta seed oil into biodiesel.     

酯交换法制备生物柴油及其在我国的实践

生物柴油是一种对环境友好的可再生燃料,以其是好的环境效应受到越来越多的关注。综述并比较了生物柴油的各种化学制备方法,介绍了该产业的国内外生产应用情况,指出了生物柴油的优势,分析了生物柴油在生产厦使用过程中存在的一些问题并对生物柴油的未来研究与发展作了展望。     

Synthesis of biodiesel from waste vegetable oil with large amounts of free fatty acids using a carbon-based solid acid catalyst

A carbon-based solid acid catalyst was prepared by the sulfonation of carbonized vegetable oil asphalt. This catalyst was employed to simultaneously catalyze esterification and transesterification to synthesis biodiesel when a waste vegetable oil with large amounts of free fatty acids (FFAs) was used as feedstock. The physical and chemical properties of this catalyst were characterized by a variety of techniques. The maximum conversion of triglyceride and FFA reached 80.5 wt.% and 94.8 wt.% after 4.5 h at 220 °C, when using a 16.8 M ratio of methanol to oil and 0.2 wt.% of catalyst to oil. The high catalytic activity and stability of this catalyst was related to its high acid site density (–OH, Brönsted acid sites), hydrophobicity that prevented the hydration of –OH species, hydrophilic functional groups (–SO₃H) that gave improved accessibility of methanol to the triglyceride and FFAs, and large pores that provided more acid sites for the reactants.     

Lipase immobilized carbon nanotubes for conversion of Jatropha oil to fatty acid methyl esters

Lipase has been immobilized on multi-walled carbon nanotubes (MWCNTs) through the reaction of the carboxylated nanotubes with the enzyme in the presence of N-hydroxysulfosuccinimide (NHS) and 1-ethyl-3-[3-dimethylaminopropyl]carbodiimide hydrochloride. Successful immobilization has been verified by infrared spectroscopy and scanning electron microscopy. The synthesized biomaterial has been used for catalyzing the conversion of Jatropha oil to the fatty acid methyl esters (FAME). Progress of the conversion reaction has been monitored with NIR spectroscopy. Gas chromatographic studies have indicated that the use of lipase–MWCNT bioconjuagate leads to almost quantitative conversion of Jatropha oil to the FAME. Around 1 h of the reaction, in the presence of around 15% of catalyst (mass fraction of catalyst on the total mixture), has yielded the desired results. The above used catalyst support has been regenerated 10 times without any adverse effect on the enzyme activity.     

Toward estimation of biodiesel production from castor oil using ANN

Nowadays, a green replacement for the conventional petrodiesel introduced as biodiesel in which its economical production way is using feedstock. Also, environmentally friendly fuels attracted more attention due to the serious global warming problem. In the present study, two different artificial intelligencebased modeling was utilized to predict the production of biodiesel from castor oil. Also, a comparison between the two methods was carried out, and the more applicable method for the prediction of biodiesel production was introduced. To this end, biodiesel production yield from castor oil assumed to be the target of the model and various parameters such as temperature (T), time (S), methanol to oil molar ratio, and catalyst weight (C) expected as input parameters. ANN modeling shows high accuracy and robustness for the prediction of biodiesel production, and statistical parameters such as coefficient of determination and root-mean-square error are 0.9984 and 1.13, respectively.     

Lipase-catalysed transesterification: Viewpoint of the mechanism and influence of free fatty acids

A series of lipase-catalysed transesterification experiments were carried out to study the effect of the presence of free fatty acids on synthesis reaction rate and the stability of the biocatalyst, and also to elucidate the underlying process, which remains a subject of debate. Based on the results, the reaction rate and biocatalyst stability increased with increasing content in free fatty acids of the reaction mixture. Also, tests carried out with a mixture of triolein and linoleic acid revealed that the transesterification is a combination of direct alcoholysis of triacylglycerols and a two-step reaction involving hydrolysis of acylglycerols and further esterification of previously released free fatty acids. The time course of triacylglycerols and diacylglycerols revealed that the enzyme is similarly selective for both types of substrate.     

One-step production of biodiesel through simultaneous esterification and transesterification from highly acidic unrefined feedstock over efficient and recyclable ZnO nanostar catalyst

Zinc oxide (ZnO) nanostar synthesized by simple and up-scalable microwave-assisted surfactant free hydrolysis method was applied as catalyst for biodiesel synthesis through one-step simultaneous esterification and transesterification from high free fatty acid (FFA) contaminated unrefined feedstock. It was found that ZnO nanostar catalyst was reacted with FFA to yield zinc oleate (ZnOl) as intermediate and finally became zinc glycerolate (ZnGly). With the re-deposition of ZnGly back to the ZnO nanostar catalyst at the end of the reaction, the catalyst can be easily recovered and stay active for five cycles. Furthermore, the rate of transesterification is highly promoted by the presence of FFA (6 wt.%) which makes it an efficient catalyst for low grade feedstock like waste cooking oil and crude plant oils.     

大豆酸化油制备生物柴油的研究

试验研究了大豆酸化油在复合酸催化剂的作用下与甲醇发生转酯化和酯化反应生成脂肪酸甲酯(生物柴油)的最佳反应条件.试验结果表明,该酯化及转酯化反应的最佳操作条件:复合酸催化剂的用量为大豆油质量的5%、油醇摩尔比为1:6、反应时间为6h、反应温度为65℃.