Acid base catalyzed transesterification kinetics of waste cooking oil

The present study reports the results of kinetics study of acid base catalyzed two step transesterification process of waste cooking oil, carried out at pre-determined optimum temperature of 65 °C and 50 °C for esterification and transesterification process respectively under the optimum condition of methanol to oil ratio of 3:7 (v/v), catalyst concentration 1%(w/w) for H₂SO₄ and NaOH and 400 rpm of stirring. The optimum temperature was determined based on the yield of ME at different temperature. Simply, the optimum concentration of H₂SO₄ and NaOH was determined with respect to ME Yield. The results indicated that both esterification and transesterification reaction are of first order rate reaction with reaction rate constant of 0.0031 min^− 1 and 0.0078 min^− 1 respectively showing that the former is a slower process than the later. The maximum yield of 21.50% of ME during esterification and 90.6% from transesterification of pretreated WCO has been obtained. This is the first study of its kind which deals with simplified kinetics of two step acid-base catalyzed transesterification process carried under the above optimum conditions and took about 6 h for complete conversion of TG to ME with least amount of activation energy. Also various parameters related to experiments are optimized with respect to ME yield.     

Optimization of the transesterification reaction in biodiesel production

In this paper response surface methodology (RSM) was used to study the transesterification reaction of rapeseed oil for biodiesel production. The three main factors that drive the conversion of triglycerides into fatty acid methyl esters (FAME) were studied according to a full factorial design at two levels. These factors were catalyst concentration (KOH), temperature and reaction time. The range investigated for each factor was selected taking into account the process of Fox Petroli S.p.A. Analysis of variance (ANOVA) was used to determine the significance of the factors and their interactions which primarily affect the first of the two transesterification stages. This analysis evidenced the best operating conditions of the first transesterification reaction performed at Fox’s plant: KOH concentration 0.6% w/w, temperature 50 °C and reaction time 90 min with a CH₃OH to KOH ratio equal to 60. Three empirical models were derived to correlate the experimental results, suitable to predict the behavior of triglyceride, diglyceride and monoglyceride concentration. These models showed a good agreement with the experimental results, demonstrating that this methodology may be useful for industrial process optimization.     

甲醇钠催化地沟油制备生物柴油研究

以浓硫酸为催化剂,高酸值地沟油与甲醇酯化反应降酸的最优工艺条件为:n(甲醇):n(地沟油)=9:1,m(浓硫酸):m(地沟油)=1.1％,反应温度60℃,反应时间5h.制备生物柴油的最优工艺条件为:以甲醇钠为催化剂,反应时间2h,反应温度65℃,n(甲醇):n(地沟油)=7:1,m(甲醇钠):m(地沟油)=0.8％.制...     

Biodiesel production from waste cooking oil via alkali catalyst and its engine test

Waste cooking oils (WCO), which contain large amounts of free fatty acids produced in restaurants, are collected by the environmental protection agency in the main cities of China and should be disposed in a suitable way. Biodiesel production from WCO was studied in this paper through experimental investigation of reaction conditions such as methanol/oil molar ratio, alkaline catalyst amount, reaction time and reaction temperature which are deemed to have main impact on reaction conversion efficiency. Experiments have been performed to determine the optimum conditions for this transesterification process by orthogonal analysis of parameters in a four-factor and three-level test. The optimum experimental conditions, which were obtained from the orthogonal test, were methanol/oil molar ratio 9:1, with 1.0 wt.% sodium hydroxide, temperature of 50 °C and 90 min. Verified experiments showed methanol/oil molar ratio 6:1 was more suitable in the process, and under that condition WCO conversion efficiency led to 89.8% and the physical and chemical properties of biodiesel sample satisfied the requirement of relevant international standards. After the analysis main characteristics of biodiese sample, the impact of biodiesel/diesel blend fuels on an YC6M220G turbo-charge diesel engine exhaust emissions was evaluated compared with 0# diesel. The testing results show without any modification to diesel engine, under all conditions dynamical performance kept normal, and the B20, B50 blend fuels (include 20%, 50% crude biodiesel respectively) led to unsatisfactory emissions whilst the B′20 blend fuel (include 20% refined biodiesel) reduced significantly particles, HC and CO etc. emissions. For example CO, HC and particles were reduced by 18.6%, 26.7% and 20.58%, respectively.     

玉米油制备生物柴油的研究

研究了以玉米油、甲醇为原料,以氢氧化钠为催化剂制备生物柴油。对影响产品质量和产率的4个因素进行了系统的研究。结果表明,最佳反应条件为:原料配比m(玉米油)∶m(甲醇)=3∶1,氢氧化钠为玉米油质量的1%,反应温度60℃,回流反应时间70 m in。得到的生物柴油收率最高,可达95.33%。     

预酯化-酯交换法利用餐饮废油脂制备生物柴油

以高酸值餐饮废油脂和乙醇为原料,采用预酯化-酯交换法制备生物柴油。第一步为预酯化反应,控制反应温度为70℃,最佳条件为:催化剂加入量为4%,反应时间为90min,带水剂加入量为10%,乙醇加入量控制在醇酸摩尔比为6∶1,可使油脂酸值降至4mg KOH·g-1以下,满足酯交换反应要求。第二步为酯交换反应,最佳条件是:醇油摩尔比为8∶1,碱性催化剂加入量为0.8%,反应温度为70℃,反应时间为30min。本方法具有反应时间短、转化率高,反应条件温和,清洁环保等优点。     

Microwave assisted transesterification of rapeseed oil

Rapeseed is one of the important vegetable oil sources for biodiesel production due to its high oil content (around 40%). In this study rapeseed oil was converted to biodiesel by transesterification using microwave heating. Experiments were carried out in the presence of two different alkali catalysts which are sodium hydroxide and potassium hydroxide. Effects of various reaction parameters such as catalyst ratio, reaction temperature and time were investigated. Mono-, di- and triglyceride content of biodiesel were determined by gas chromatography analysis. Yield and purity (ester content) percentages of biodiesel were specified in weight, which are 88.3–93.7% and 87.1–99.4%, respectively. The results indicated that microwave heating has effectively increased the biodiesel yield and decreased the reaction time.     

Microwave irradiation-assisted transesterification of soybean oil to biodiesel catalyzed by nanopowder calcium oxide

This study examined the effect of a heterogeneous base catalyst on the transesterification of soybean oil assisted by microwave irradiation. The results showed that nanopowder calcium oxide (nano CaO) was very efficient in converting soybean oil to biodiesel, and microwave irradiation is more efficient than the conventional bath for biodiesel production. However, the water content of methanol can not improve the conversion rate catalyzed by nano CaO.The suitable reaction conditions that can reach a 96.6% of conversion rate were methanol/oil molar ratio, 7:1; amount of catalyst used, 3.0 wt.%; reaction temperature, 338 K; and reaction time, 60 min. The biodiesel produced is within the limits prescribed by the standard of EN-14214.     

Optimization of polyol ester production by transesterification of Jatropha-based methyl ester with trimethylolpropane using Taguchi design of experiment

Polyol ester production from transesterification of Jatropha oil methyl ester (JOME) and trimethylolpropane (TMP) was investigated. The effects of temperature, pressure, ratio of JOME:TMP and catalyst amount were studied in optimization experiment, using Taguchi L9 experimental layout. The parameters explored were found to have a significant impact on the reaction. The order of importance of the variables was found to be pressure, temperature, JOME:TMP molar ratio and catalyst. The optimum reaction conditions were identified to be 483 K, 25 kPa; 1.0% w/w catalyst and JOME:TMP molar ratio of 4:1. At this optimum condition the JOME conversion obtained was 91.5%. Confirmation experiments were performed to demonstrate the effectiveness of this approach after the optimum levels of process parameters were determined.     

Alkali catalyzed transesterification of safflower seed oil assisted by microwave irradiation

The safflower (Carthamus tinctorius L.) oil was extracted from the seeds of the safflower that grows in Diyarbakir, SE Anatolia of Turkey. Biodiesel has been prepared from safflower seed by transesterification of the crude oil under microwave irradiation, with methanol to oil molar ratio of 10:1, in the presence of 1.0% NaOH as catalyst. The conversion of C. tinctorius oil to methyl ester was over 98.4% at 6 min. The important fuel properties of safflower oil and its methyl ester (biodiesel) such as density, kinematic viscosity, flash point, iodine number, neutralization number, pour point, cloud point, cetane number are found out and compared to those of no. 2 petroleum diesel, ASTM and EN biodiesel standards. Compared with conventional heating methods, the process using microwaves irradiation proved to be a faster method for alcoholysis of triglycerides with methanol, leading to high yields of biodiesel.     

在混凝土中掺入纯碱废渣生产建材制品的研究

介绍了利用纯碱厂碱渣掺入混凝土制备建材制品的试验,并通过一定工艺过程制成不同配比的试块,探索废渣对混凝土性能指标的影响。     

Conventional and in situ transesterification of sunflower seed oil for the production of biodiesel

In the present work the alkaline transesterification of sunflower seed oil with methanol and ethanol, for the production of biodiesel fuel was studied. Both conventional and in situ transesterification were investigated using low frequency ultrasonication (24 kHz) and mechanical stirring (600 rpm). Use of ultrasonication in conventional transesterification with methanol gave high yields of methyl esters (95%) after a short reaction time (20 min) similar to those using mechanical stirring. Use of ultrasonication in conventional transesterification with ethanol gave similar yields to those using mechanical stirring but significantly lower than respective yields using methanol. In the in situ transesterification the use of ultrasonication and mechanical stirring led to similar high yields (95%) of methyl esters after approximately 20 min of reaction time. In the presence of ethanol use of ultrasonication led to high ester yields (98%) in only 40 min of reaction time while use of mechanical stirring gave lower yields (88%) even after 4 h of reaction time.

 In situ transesterification gave similar ester yields to those obtained by conventional transesterification being an alternative, efficient and economical process. In all cases a concentration of 2.0% NaOH gave higher ester yields.

 Reaction rate constants were calculated, using first order reaction kinetics, to be equal to 3.1 × 10^− 3 s^− 1 for conventional transesterification using methanol and 2.0% NaOH, and 9.5 × 10^− 4 s^− 1 using ethanol.     

氧氯化法生产二氯乙烷的废碱液回收利用

为消除氧氯化法生产二氟乙烷中产生的废碱液对系统水处理的影响,采用蒸馏法对废碱液进行单独处理,实现碱液中的二氯乙烷含量降低至1μg/g以下,满足废水处理要求.该改造工程投用后生产稳定,废碱液得到综合利用,具有良好的经济效益和环境效益.     

猪板油直接萃取制备生物柴油的研究

研究了猪油原位萃取-酶法转化制生物柴油。考察了溶剂用量、萃取时间、萃取温度等对油脂得率的影响,探讨了以Novozyme 435酶为催化剂直接转化猪油生物柴油。结果表明,萃取猪油的较优参数为:乙酸甲酯为萃取剂,乙酸甲酯用量(mL)与猪板油质量(g)比为8∶1,萃取时间3 h,萃取温度50℃;以Novozyme 435脂肪酶转化猪油制备生物柴油,得率为95.12%,当Novozyme 435酶和Lipozyme TLIM酶混合比为1∶1时,生物柴油转化率最高,达97.12%。     

甲基磺酸催化高酸值地沟油酯化反应动力学研究

为研究地沟油中的长链脂肪酸酯化反应动力学以及反应条件对反应速率的影响,以甲基磺酸催化高酸值地沟油与甲醇的酯化反应为研究体系,反应中甲醇被持续通入地沟油中,同时不断蒸出未反应完的甲醇与生成的水。测定地沟油与甲醇酯化反应速率常数,结果表明,甲基磺酸催化高酸值地沟油与甲醇的酯化反应为一级反应,反应活化能为76.06 kJ·mol^-1,提高甲醇流量、催化剂用量和反应温度都能提高反应速率。     

高酸值废油脂的对甲苯磺酸催化乙酯化反应

以价格低廉易得的废油脂为原料制备生物柴油,不但能带来巨大的经济效益,而且符合绿色环保的产业发展要求。但是废油脂通常具有较高的酸值,因此在以碱催化酯交换法制备生物柴油之前,需对高酸值原料油进行降酸处理。考察了相关条件对油脂预酯化反应的影响。结果表明,最佳条件为:催化剂加入量为4%,反应时间为90 min,带水剂加入量为10%,乙醇醇酸摩尔比为6∶1。     

废油脂预处理及制备生物柴油研究进展

介绍了废油脂的预处理工艺及我国废油脂的现状,重点阐述了国内外以废油脂为原料经碱法、酸法和酶法酯交换制备生物柴油的研究情况,并对目前存在的问题和相应的解决对策进行了简单的讨论。     

Micro‐reactor for transesterification of plant seed oils

The fatty acid compositions of vegetable or other plant seed oils are generally determined by gas chromatography (GC). Methyl esters (the most volatile derivatives) are the preferred derivatives for GC analysis. Esters of higher alcohols are good for the separation of volatile and positional isomers. All the esters of the C₁–C₈ alcohols of vegetable oils were silmilarly prepared by passing the reaction mixture containing the desired alcohol, oil and tetrahydrofuran through the micro‐reactor (a 3‐mL dispossible syringe packed with 0.5 g of NaOH powder). The reaction products were acidified with acetic acid and the mixture was analyzed by high‐performance size exclusion chromatography and GC. Transesterification was quantitative for primary alcohols, but an appreciable amount of free fatty acids was formed for secondary alcohols. Coriander seed oil was quantitatively esterified with 2‐ethyl 1‐hexanol with the micro‐reactor in less than 1 min. Oleic and petroselinic acid 2‐ethyl 1‐hexyl esters are baseline separated on an Rtx‐2330 capillary column (30 m×0.25 mm, 0.25 µm film thickness).     

Biodiesel production from waste cooking oil over alkaline modified zirconia catalyst

Screening and catalytic activity of alkaline modified zirconia i.e. Mg/ZrO₂, Ca/ZrO₂, Sr/ZrO₂, and Ba/ZrO₂ as heterogeneous catalyst in biodiesel production from waste cooking oil (WCO) have been investigated. The catalysts were prepared via wet impregnation of alkaline nitrate salts supported on zirconia. Physico-chemical characteristics of the catalysts were analyzed by BET surface area, XRD, FESEM and CO₂–NH₃–TPD. Among the catalysts screened, Sr/ZrO₂ exhibited higher catalytic activities. Characterization results disclosed Sr/ZrO₂ catalyst possessed balanced basic and acid site concentrations with its pore volume, surface area as well as pore diameters suitable for biodiesel production. The balanced active sites facilitated simultaneous transesterification and esterification of WCO. A plausible mechanism has been suggested for the simultaneous reactions. The effects of operating process conditions such as methanol to oil molar ratio, reaction temperature and catalyst loading on biodiesel production in the presence of Sr/ZrO₂ were investigated. Methyl ester (ME) yield at 79.7% was produced over 2.7 wt.% catalyst loading (Sr/ZrO₂), 29:1 methanol to oil molar ratio, 169 min of reaction time and 115.5 °C temperature.