Parametric study of biodiesel production from used soybean oil

Biodiesel, an alternative diesel fuel derived from vegetable oil, animal fat, or waste vegetable oil (WVO), is obtained by reacting the oil or fat with an alcohol (transesterification) in the presence of a basic catalyst to produce the corresponding mono‐alkyl esters. In this work, the effect of the catalyst KOH‐to‐WVO ratio, ethanol concentration, and time of reaction on the biodiesel yield were investigated. The transesterification reaction was performed at a constant temperature (35 °C) in order to minimize the cost of heating and ethanol evaporation. A 2³ complete factorial design on biodiesel yield (Y) was performed using low and high levels of operating variables: KOH concentration (9–14 g/L), ethanol concentration (30–40 vol‐%) and time (30–40 min). The complete factorial model that can be used to fit the data was determined. The model shows that interactions exist among the parameters and that the parameters, or factors, do not operate independently on the response (biodiesel yield). The highest yield was obtained in the first 30 min of reaction time. The results indicate that the highest yield was 78.5 vol‐% using a KOH‐to‐WVO ratio of 12 g/L and 30 vol‐% ethanol. The ASTM tests indicate that the biodiesel properties are within the biodiesel standard limits.     

An enzymatic/acid-catalyzed hybrid process for biodiesel production from soybean oil

The present study is aimed at developing an enzymatic/acid-catalyzed hybrid process for biodiesel production using soybean oil as feedstock. In the enzymatic hydrolysis, 88% of the oil taken initially was hydrolyzed by binary immobilized lipase after 5 h under optimal conditions. The hydrolysate was further used in acid-catalyzed esterification for biodiesel production and the effects of temperature, catalyst concentration, feedstock to methanol molar ratio, and reaction time on biodiesel conversion were investigated. By using a feedstock to methanol molar ratio of 1:15 and a sulfuric acid concentration of 2.5%, a biodiesel conversion of 99% was obtained after 12 h of reaction at 50 °C. The biodiesel produced by this process met the American Society for Testing and Materials (ASTM) standard. This hybrid process may open a way for biodiesel production using unrefined and used oil as feedstock.     

非水相脂肪酶催化大豆油脂合成生物柴油的研究

脂肪酶Lipozyme TL IM在非水相体系中能有效催化大豆油脂转化生成生物柴油.在优化条件下(醇油摩尔比41,反应温度40C,硅胶负载脂肪酶与油的质量比为60%),反应5h后产物脂肪酸甲酯得率可达92%.实验证明加入有机溶剂以及分批加入甲醇等均能有效提高本反应体系中脂肪酶的催化活性.     

叔戊醇体系酶促大豆油制备生物柴油

叔戊醇作为反应介质,固定化脂肪酶Novozym 435催化大豆油与甲醇的转酯反应制备生物柴油。叔戊醇消除了反应底物甲醇及反应副产物甘油对酶活的负面影响。定量分析表明,叔戊醇与油脂的体积比为1,甲醇与油脂的摩尔比为3,2%脂肪酶,反应体系含水量2%,40 ℃、180 r/min条件下反应15 h,生物柴油得率可达97%。在最适条件下反应进行160批次,酶仍保持了较高的活性和良好的稳定性。     

Marble slurry derived hydroxyapatite as heterogeneous catalyst for biodiesel production from soybean oil

In this study, utilization of waste marble slurry (MS) as an eco‐friendly and low‐cost heterogeneous catalyst is introduced for biodiesel production from soybean oil. Catalytic transesterification reaction was done to convert biodiesel from soybean oil using Marble slurry (MS) derived calcined marble slurry (CMS), and hydroxyapatite (HAP) as a heterogeneous catalyst. Marble slurry derived catalysts were characterized by XRD, FTIR, SEM, and TGA with elemental analysis. Hammett indicator method and ion exchange method were also used to verify catalytic activities of the catalysts. The HAP provided the better biodiesel yield of 94 ± 1 % with the highest basicity (13.30 mmol/g) and basic strength than CMS under optimized reaction conditions: reaction temperature 65 °C; reaction time 3 h; methanol/oil molar ratio 9:1; and catalyst concentration 6 wt%. Reusability tests provide confirmation about the stability of the catalyst and slight fluctuations in catalytic activity and biodiesel yield when used up to five runs.

     

Optimization of the production of biodiesel from soybean oil by ultrasound assisted methanolysis

This paper evaluates and optimizes the production of biodiesel from soybean oil and methanol using sodium hydroxide as catalyst. The study and optimization was carried out at low catalyst concentration (0.2 to 0.6 w/w). The reaction was carried out with application of low-frequency high-intensity ultrasound under atmospheric pressure and ambient temperature in a batch reactor. Response surface methodology (RSM) was used to evaluate the influence of methanol to oil ratio and catalyst concentration on soybean oil conversion into biodiesel. Analysis of the operating conditions by RSM showed that the most important operating condition affecting the reaction was the methanol to oil ratio, while catalyst amount showed little significance in the transesterification reaction. Total consumption of oil was obtained when alcohol to oil ratio of 9:1 and catalyst concentration of 0.2 w/w were applied.     

Novel biodiesel production technology from soybean soapstock

This paper describes an attractive method to make biodiesel from soybean soapstock (SS). A novel recovery technology of acid oil (AO) from SS has been developed with only sulfuric acid solution under the ambient temperature (25±2 °C). After drying, AO contained 50.0% FFA, 15.5% TAG, 6.9% DAG, 3.1% MAG, 0.8% water and other inert materials. The recovery yield of AO was about 97% (w/w) based on the total fatty acids of the SS. The acid oil could be directly converted into biodiesel at 95 °C in a pressurized reactor within 5 hours. Optimal esterification conditions were determined to be a weight ratio of 1 : 1.5 : 0.1 of AO/methanol/sulfuric acid. Higher reaction temperature helps to shorten the reaction time and requires less catalyst and methanol. Ester content of the biodiesel derived from AO through one-step acid catalyzed reaction is around 92%. After distillation, the purity of the biodiesel produced from AO is 97.6% which meets the Biodiesel Specification of Korea. The yield of purified biodiesel was 94% (w/w) based on the total fatty acids of the soapstock.     

Reactive distillation for methyl acetate production

We describe a hierarchy of methods, models, and calculation techniques that support the design of reactive distillation columns. The models require increasingly sophisticated data needs as the hierarchy is implemented. The approach is illustrated for the production of methyl acetate because of its commercial importance, and because of the availability of adequate published data for comparison. In the limit of reaction and phase equilibrium, we show (1) the existence of both a minimum and a maximum reflux, (2) there is a narrow range of reflux ratios that will produce high conversions and high purity methyl acetate, and (3) the existence of multiple steady states throughout the entire range of feasible reflux ratios. For finite rates of reaction, we find (4) that the desired product compositions are feasible over a wide range of reaction rates, up to and including reaction equilibrium, and (5) that multiple steady states do not occur over the range of realistic reflux ratios, but they are found at high reflux ratios outside the range of normal operation. Our calculations are in good agreement with experimental results reported by Bessling et al., [Chemical Engineering Technology 21 (1998) 393].     

An integrated reactive distillation process for biodiesel production

An integrated reactive distillation process for biodiesel production is proposed. The reactive separation process consists of two coupled reactive distillation columns (RDCs) considering the kinetically controlled reactions of esterification of the fatty acids (FFA) and the transesterification of glycerides with methanol, respectively. The conceptual design of the reactive distillation columns was performed through the construction of reactive residue curve maps in terms of elements. The design of the esterification reactive distillation column consisted of one reactive zone loaded with Amberlyst 15 catalyst and for the transesterification reactive column two reactive zones loaded with MgO were used. Intensive simulation of the integrated reactive process considering the complex kinetic expressions and the PC-SAFT EOS was performed using the computational environment of Aspen Plus. The final integrated RD process was able to handle more than 1% wt of fatty acid contents in the vegetable oil. However, results showed that the amount of fatty acids in the vegetable oil feed plays a key role on the performance (energy cost, catalyst load, methanol flow rate) of the integrated esterification–transesterification reactive distillation process.     

Highly efficient procedure for the synthesis of biodiesel from soybean oil

The novel efficient procedure has been developed for the synthesis of biodiesel from soybean oil and methanol. K₂CO₃ supported on MgO has been selected as the most efficient catalyst for the reaction with the yield of 99%. Operational simplicity, low cost of the catalyst used, high yields, short reaction time and reusability are the key features of this methodology.     

The use of a modified TDSP for biodiesel production from soybean, linseed and waste cooking oil

In this study, the Transesterification Double Step Process (TDSP) for the production of biodiesel from vegetable oil was modified to yield a shorter reaction time and products with improved quality. TDSP consists in a two step transesterification procedure which starts with a basic catalysis, followed by an acidic catalysis. The process modifications included a reduction in the concentration of catalysts, a reduction in the reaction time of the first step and the direct mixing of methanol/acid solution, without cooling the system between the first and second step. A comparison between washed and unwashed biodiesel demonstrates that the final washing and drying procedure is necessary for satisfactory results. The products were analyzed by ¹H-NMR and nineteen different biodiesel analyses specific for international quality certification. The modified procedure resulted in a high conversion index (97% for waste cooking oil and soybean oil and 98% for linseed oil) and high yield (87 ± 5% for waste cooking oil, 92 ± 3% for soybean and 93 ± 3% for linseed oil). The biodiesel produced by the modified TDSP met ASTM, EN ISO and ABNT standards before the addition of stabilizer.     

Carbon-based nanostructured catalyst for biodiesel production by catalytic distillation

A promising carbon-based nanostructured catalyst was prepared via the following four steps: (1) thermal decomposition of organometallic compound (C₁₀H₁₄CoO₄) on 304 stainless steel substrate, (2) cracking of benzene to carbon nanotubes (CNTs) on the substrate using Co particle catalyst, (3) sulfurizing CNTs with Na₂S_x, and (4) oxidating the sulfurized CNTs with hydrogen peroxide. The as-prepared carbon-based catalyst was characterized by spectroscopy, scanning electron microscopy, transmission electron microscopy etc. The monolithic catalyst can serve as appropriate filler for a catalytic distillation column. Catalytic activity was examined by catalyzing the transesterification of soybean oil and methanol to biodiesel in the catalytic distillation column.     

碱催化法制备生物柴油工艺研究

在250m l间歇式高压反应器中,以大豆油为原料,研究KOH催化甲醇酯交换反应制备生物柴油的工艺条件。主要考察了醇油摩尔比、反应温度、反应时间、催化剂用量等操作条件对脂肪酸甲酯转化率的影响。结果表明,当KOH用量为1%(wt),醇油摩尔比为5∶1,反应温度为65℃时,反应时间为15m in,脂肪酸甲酯的转化率可以达到92%。     

离子液体催化大豆油制备生物柴油

制备了对水稳定性好、带—SO₃H官能团的咪唑丙烷磺酸硫酸氢盐离子液体，并以其作为催化剂进行了大豆油酯交换反应制备生物柴油的研究。考察了离子液体的用量、醇与油物质的量比、反应温度和反应时间对酯交换反应的影响及离子液体的稳定性。实验结果表明，在n(甲醇)∶n(大豆油) =12∶1、反应温度120 ℃、反应时间8 h和催化剂用量为原料油质量的4.0%条件下,产物中脂肪酸甲酯收率可达96.5%,且离子液体的稳定性好,可循环使用。     

Standard biodiesel from soybean oil by a single chemical reaction

Laboratory methods are described for producing standard biodiesel from low-acid-number vegetable oils in single-step reactions without distillation of the products. Either sodium hydroxide or methoxide is used as the catalyst. Biodiesel fuel is currently made from vegetable oils using basic catalysts. With this methodology, the oils must be reacted two or three times with methanol, in the presence of sodium methoxide, to make a product that meets the standard for the total chemically bound and unbound glycerol content. Previously it was thought that sodium hydroxide could never be used as the catalyst because it forms soap with the ester, which lowers the yield and makes product isolation difficult. Two of the described methods use sodium hydroxide as the catalyst and the other uses sodium methoxide. These methods rely on the use of oxolane as co-solvent to manipulate phase behavior during the reaction. Reactant molar ratios and base concentrations are also optimized to drive the reactions to the necessary degree of completion.     

Modifying soybean oil for enhanced performance in biodiesel blends

Soybean (Glycine max Merr.) oil is primarily composed of five fatty acids; palmitic acid (∼13%), stearic acid (∼4%), oleic acid (∼18%), linoleic acid (∼55%) and linolenic acid (∼10%). The average U.S. production of soybean oil from 1993 to 1995 was 6.8 billion kg and in 2002 soybeans were harvested from more than 30 million ha across the U.S., which accounts for 40% of the total world soybean output. This production capacity accounts for more than 50% of the total available biobased oil for industrial applications. A useful industrial application of soybean oil is in biodiesel blends. On a liquid basis, the total soybean oil production capacity would be equivalent to 1.9 billion gal of diesel, about 6.9% of the diesel fuel consumed in the United States for transportation in 1996. A number of positive attributes are realized with the use of soybean oil-derived biodiesel, including enhanced biodegradation, increased flashpoint, reduced toxicity, lower emissions and increased lubricity. However, the two parameters that have limited usefulness of a soybean oil-derived biodiesel as a fuel are oxidative instability and cold flow in northern climates. The latter is not an issue in warmer environments, and thus soybean oil modifications designed to maximize engine performance should be targeted with marketplace locale considerations in mind. Implementing the tools of biotechnology to modify the fatty acid profile of soybean for locale performance enhancement may increase the attractiveness of biodiesel derived from this commodity crop.     

棕榈油酯交换制备生物柴油的反应动力学

在甲醇与棕榈油的摩尔比为6∶1和催化剂KOH用量为棕榈油质量1.0%的条件下,研究不同温度下棕榈油制备生物柴油的酯交换反应动力学,采用Origin软件拟合曲线方程,建立棕榈油酯交换反应的宏观动力学模型。研究结果表明:棕榈油制备生物柴油的酯交换反应遵循1.40级动力学方程,反应速率随温度的升高而加快,二者符合Arrhenius方程,该反应的活化能为27.23 kJ/mol,频率因子为1.4×103。文中研究建立的反应动力学模型将对扩大试验研究提供理论依据和基础数据支持。     

Comparative kinetics of transesterification for biodiesel production from palm oil and mustard oil

The kinetics of palm oil and mustard oil transesterification are compared. Transesterification of palm oil and mustard oil using KOH as a catalyst was performed at various reaction temperatures ranging from 40 to 60°C. The reaction steps are reversible and transesterification is favoured at elevated temperatures. The reaction step of triglyceride to diglyceride is the rate determining step (RDS) that controls kinetics of overall transesterification with activation energies of 30.2 and 26.8 kJ/mol for palm oil and mustard oil transesterification, respectively. It is found that percentage of saturated compounds play a vital role on transesterification kinetics. © 2011 Canadian Society for Chemical Engineering     

Mg-Al类水滑石催化大豆油酯交换制备生物柴油

采用共沉淀法制备了不同n(Mg)/n(Al)比的Mg-Al类水滑石,在不同温度下焙烧得到复合氧化物,作为大豆油与甲醇反应制备生物柴油的催化剂。结果表明,未焙烧Mg-Al类水滑石的催化活性较差,而n(Mg)/n(Al)=3的类水滑石在450℃焙烧时具有极高的催化活性。在反应温度65℃,醇/油15,催化剂用量为大豆油质量的2%,反应3 h,生物柴油产率可达97.4%。催化剂回收再用性能良好,重复使用3次,生物柴油收率仍在90%左右。