杂化膜催化酯化与固体碱酯交换集成工艺制备生物柴油

以废鸡油为原料,建立杂化膜催化酯化-固体碱催化酯交换集成工艺制备生物柴油。考察醇油质量比、反应温度等对酯化反应的影响。采用气相色谱分析产物中脂肪酸组成;核磁共振氢谱计算鸡油中甘油三酯酯交换反应的转化率。结果表明,最佳工艺条件为:反应温度338 K,甲醇与废鸡油质量比为3∶1,鸡油酯化反应转化率为93.5%。气相色谱显示,废鸡油原料中含有的五种脂肪酸都转化成为脂肪酸甲酯,鸡油酯交换反应转化率为98.1%。制备出的生物柴油样品酸值、密度、运动黏度、闪点和硫含量多项指标均满足我国GBT 20828—2015、美国ASTM 6751—06e1和欧洲EN 14214生物柴油标准。     

地沟油固体碱催化酯交换反应制备生物柴油

以固体碱催化剂中典型的负载型固体碱催化剂(K2CO3/人造沸石、KF/Al2O3催化剂和CaO/人造沸石催化剂)作为酯交换反应的催化剂,利用地沟油经过酯交换反应制取生物柴油,对比不同催化剂的催化效率以及重复使用效率,从中选择最优固体碱催化剂,并选择最优催化剂研究其最佳工艺条件。最终产物通过GC-MS进行表征。     

固体碱催化酯交换反应制备生物柴油研究进展

介绍了非负载型和负载型2类固体碱催化剂用于制备生物柴油的研究进展,采用酯交换法因其无需消耗大量能量、操作方法简单,成为制备生物柴油的主要方法,并随着负载型固体碱催化剂载体的纳米化、介孔化,纳米级以及以分子筛作为载体的固体碱催化剂将成为一个主要的研究方向。认为开发更加稳定、耐水、耐酸的固体碱催化将是今后固体碱催化剂的研究重点。     

固体碱催化酯交换法制备生物柴油的研究

用浸渍法制备了KF/Al2O3负载催化剂,并将负载催化剂用于菜籽油与甲醇酯交换合成生物柴油的研究。考查了不同负载量、不同煅烧温度对催化剂活性的影响,肯定了KF/Al2O3催化剂存在产生强碱位,并利用GC-MS对生物柴油进行了检测。结果表明,生物柴油的主要成分为油酸甲酯,其含量达到50%以上。     

棉籽油酯交换制备生物柴油固体碱催化过程研究

生物柴油(脂肪酸甲酯)可以由棉籽油与甲醇在碱催化剂的作用下通过酯交换反应制得.本实验通过高温煅烧氢氧化镁、碳酸钙及镁-铝水滑石得到了相应的固体碱催化剂MgO、CaO及MgO-Al2O3,并对催化剂活性进行评价.实验结果表明,CaO及MgO-Al2O3具有较高的酯交换反应活性:在230℃,醇油摩尔比12:1及催化剂用量为棉籽油2%(wt)的条件下,反应3 h后,甲酯的收率达到90%以上.CO2-TPD实验结果表明,CaO 及MgO-Al2O3具有较强和较多的碱性位,而催化剂的活性与碱强度及碱性位数量直接相关.     

固体碱催化制备生物柴油的研究

近些年来,生物柴油已成为重要的新兴可再生能源之一。简要列举了一些固体碱的合成及其催化制备生物柴油催化性能的研究,并简单预测了今后此类催化剂可能的发展方向。     

固体碱催化大豆油制备生物柴油

以Na2Si O3·9H2O为原料制备固体碱催化剂,大豆油和甲醇酯交换反应为模型,优化固体碱焙烧条件。再以最优条件制备的Na2Si O3·9H2O固体碱催化剂优化大豆油和甲醇酯交换工艺。结果表明:硅酸钠固体碱最佳制备条件为煅烧温度400℃、煅烧时间1 h。大豆油和甲醇酯交换反应优化工艺为:反应温度65℃、醇油摩尔比6∶1、反应时间2 h。     

固体碱催化黄连木籽油制备生物柴油

制备了K2CO3/Mg(A l)O固体碱催化剂,适宜制备条件为:K2CO3负载量30%、在700℃下焙烧4 h。用比表面积测定仪、X射线衍射仪、红外光谱仪对其进行了表征。以黄连木籽油为原料,开展了酯交换法制备生物柴油的研究,考察了主要影响因素:醇油摩尔比、催化剂用量、反应时间和反应温度对酯交换反应的影响,得到的酯交换反应适宜条件为:以黄连木籽油0.01 mol计,醇油摩尔比12∶1、催化剂用量为黄连木籽油质量的4.0%、反应时间2.5 h、反应温度68℃。在该条件下生物柴油的收率可达99%以上。催化剂经4次循环使用,生物柴油收率仍可保持在96%以上。用FTIR1、HNMR对所制备的产品进行了表征,证明产品中含有饱和脂肪酸甲酯和不饱和脂肪酸甲酯。     

固体催化剂催化酯交换反应制备生物柴油研究进展

酯交换法由于无需消耗大量的能量即可制备出低黏度的生物柴油,是制备生物柴油的主要方法,发展前景较好。固体催化剂催化酯交换反应产物易分离,废弃催化剂无环境污染。综述了酯交换反应制备生物柴油过程中固体催化剂的研究概况,包括固体酸和碱催化剂的研究进展,认为采用负载型固体碱催化剂催化油脂酯交换反应合成生物柴油将成为主要的研究方向。     

分子筛固体碱催化制备生物柴油的研究进展

综述了A型、x型、Y型等微孔分子筛和MCM-41、SBA-15等介孔分子筛经改性得到的固体碱催化剂用于酯交换反应制备生物柴油的研究进展,并对制备生物柴油的分子筛固体碱催化剂研究方向提出了建议。     

Optimization of transesterification for methyl ester production from chicken fat

In this study, low cost feedstock chicken fat was used to produce methyl ester. After reducing the free fatty acid level of the chicken fat less than 1%, the transesterification reaction was completed with alkaline catalyst. Potassium hydroxide, sodium hydroxide, potassium methoxide and sodium methoxide were used as catalyst and methanol was used as alcohol for transesterification reactions. The effects of catalyst type, reaction temperature and reaction time on the fuel properties of methyl esters were investigated. The produced chicken fat methyl esters were characterized by determining their viscosity, density, pour point, flash point, acid value, methanol content, heat of combustion value, total-free glycerin, mono-di-tri glycerides, copper strip corrosion and ester yield values. The measured fuel properties of the chicken fat methyl ester met EN 14214 and ASTM D6751 biodiesel specifications when using potassium hydroxide and sodium hydroxide catalysts with high ester yield.     

Biodiesel production from waste tallow

In the present investigation an attempt has been made to use waste tallow as low cost sustainable potential feed stock for biodiesel production. Effect of various process parameters such as amount of catalyst, temperature and time on biodiesel production was investigated. The optimal conditions for processing 5 g of tallow were: temperature, 50 and 60 °C; oil/methanol molar ratio 1:30 and 1:30, amount of H₂SO_4, 1.25 and 2.5 g for chicken and mutton tallow, respectively. Under optimal conditions, chicken and mutton fat methyl esters formation of 99.01 ± 0.71% and 93.21 ± 5.07%, was obtained after 24 h in the presence of acid. The evaluation of transesterification process was followed by gas chromatographic analysis of tallow fatty acid esters. A total of 98.29% and 97.25% fatty acids were identified in chicken and mutton fats, respectively. Both fats were found highly suitable to produce biodiesel with recommended fuel properties.     

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...     

Investigations on supercritical transesterification of chicken fat for biodiesel production from low-cost lipid feedstocks

Batch experiments on chicken fat reactions with methanol were performed at supercritical conditions to answer basic questions regarding the transesterification characteristics such as reactant ratios, lipid and reaction product thermal stability, reaction reversibility, nature of the intermediates, and glycerol consumption. The experiments were conducted at temperatures of 300-400 °C, pressures up to 41.1 MPa, methanol to triglyceride molar ratios of 3:1 and 6:1, and reaction times from 2 to 6 min. The results show that the transesterification process to produce biodiesel from low-cost lipid feedstocks with low excess of methanol and without glycerol generation is technically feasible. Since thermal decomposition of chicken fat at these temperatures is an important issue to be considered, batch experiments with emphasis on this aspect were also carried out. It was found that the thermal decomposition of chicken fat was not significant if heated up to 350 °C which will permit preheating the feedstock up to this temperature in a more practical flow process. Additional experiments showed that the overall transesterification at these conditions is not reversible and that the byproduct glycerol thermally decomposed and reacted with methanol to form ethers and other fuel components. The use of low-cost lipid feedstocks and moderate excess of methanol, associated with glycerol in situ consumption, has the potential to increase biodiesel profitability for continuous flow processes that are coupled with power generation.     

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%。     

Biodiesel synthesis from waste vegetable oil via transesterification reaction in supercritical methanol

Response surface methodology (RSM) was applied to analyze the effect of four independent variables (molar ratio of methanol to oil, reaction temperature, pressure and time) on the yield of the biodiesel production via supercritical methanol (SCM) method. Waste vegetable oil (WVO) was used as raw material and transesterification reaction was performed in a supercritical batch reactor. The central composite rotatable design was used to maximize the yield of the biodiesel. The optimal values of variables were determined by RSM to be 33.8:1 (methanol/oil molar ratio) 271.1 °C, 23.1 MPa and 20.4 min reaction time for the maximum predicted yield of 95.27% (g/g). Moreover, an irreversible first order kinetic model was successfully correlated to the experimental transesterification data with 3.37 (s⁻¹) and 31.71 (kJ/mol) as the frequency factor and activation energy of the process.     

Biodiesel production via transesterification: Process safety insights from kinetic modeling

Biodiesel is an alternative non-petroleum based fuel, consisting of alkyl esters obtained either by esterification of free fatty acids with low molecular weight alcohols, or by transesterification of triglycerides. The realization of a biodiesel unit can pose several safety issues and inherent safety application opportunities as the production involves the transport, use and storage of hazardous materials, either flammable or toxic. In the experimental phase, we studied, at laboratory scale, different alkali catalysts and the relevant reaction parameters, considering inherent safety opportunities. An accurate kinetic model of the transesterification process was developed and validated, allowing to provide possible minimization and simplification plant options.     

Biodiesel production by the transesterification of cottonseed oil by solid acid catalysts

Methyl esters (biodiesel) were produced by the transesterification of cottonseed oil with methanol in the presence of solid acids as heterogeneous catalysts. The solid acids were prepared by mounting H₂SO₄ on TiO₂ · nH₂O and Zr(OH)₄, respectively, followed by calcining at 823K. TiO₂-SO₄ ²⁻ and ZrO₂-SO₄ ²⁻ showed high activity for the transesterification. The yield of methyl esters was over 90% under the conditions of 230°C, methanol/oil mole ratio of 12:1, reaction time 8 h and catalyst amount (catalyst/oil) of 2% (w). The solid acid catalysts showed more better adaptability than solid base catalysts when the oil has high acidity. IR spectral analysis of absorbed pyridine on the samples showed that there were Lewis and Br?nsted acid sites on the catalysts. Translated from The Chinese Journal of Process Engineering, 2006, 6(4): 571–575 [译自: 过程工程学报]     

Biodiesel production from waste animal fats using pyrolysis method

It is necessary to utilize waste cooking oil as a raw material of biodiesel because the land area available for cultivation in Japan is limited. Waste cooking oil also includes long-chain saturated compounds and free fatty acids derived from animal fats. The former has a high freezing point and the latter forms a soap with the alkali catalyst typically used in biodiesel production, reducing the yield. To make waste cooking oil available for biodiesel production, pyrolysis of the waste oil was attempted. The resulting triacylglycerols were found to decompose at 360 to 390 °C, fatty acids were generated by cleavage of the ester bond, and short-chain hydrocarbons and short-chain fatty acids were generated by cleavage of the unsaturated bonds in the hydrocarbon chain. When the retention time was extended with a reaction temperature of 420 °C, light-oil hydrocarbons were generated by decarboxylation of the fatty acids. By adding palladium supported by activated carbon (Pd/C) as a catalyst, decarboxylation was promoted, and hydrocarbons comparable to light oil were selectively obtained in high yield at 85 wt.%. Compared to the biodiesel obtained by transesterification, the biodiesel obtained by pyrolysis showed improvement of about − 5 °C in the pseudo-cold filter plugging point.