响应面法优化棉籽油超声强化合成生物柴油工艺的研究

以棉籽油为原料,KOH为催化剂,通过超声波强化制备生物柴油(FAME)。采用四因素二次正交旋转组合设计实验。结果表明:采用超声波强化与机械搅拌反应体系相比,反应时间从40min缩短至20min,节能效果明显;得出了超声强化合成FAME的最佳工艺条件为:醇油比6.5:1,超声时间20min,占空比28%,催化剂用量0.9%,FAME的得率为97.35%,所得生物柴油各项指标基本达到欧洲EN14214和0#生物柴油标准。     

硫酸氢钠催化生物柴油合成反应的研究

以固体酸硫酸氢钠(NaHSO4·H20)为催化剂,以菜籽油和甲醇为反应物进行酯交换反应制备脂肪酸甲酯(生物柴油).采用正交实验考察了各因素对生物柴油产率的影响,得出最佳反应条件:反应温度为90℃,反应时间为12h,醇油物质的量比为40:1,催化剂用量为菜籽油质量的6%.极差顺序为温度、反应时间、醇油物质的量比、催化剂用量.     

菜籽油超声波法制备生物柴油的研究

以菜籽油和甲醇为反应原料,以KNO3/Al2O3为催化剂,采用超声波法制备生物柴油,考察了超声波频率、醇油物质的量比、催化剂用量等条件对反应的影响。试验结果表明,该反应的最佳条件:超声波频率为30kHz,醇油物质的量比为7∶1,催化剂用量为菜籽油质量的2.0%。在此条件下,生物柴油产率为94%。所得生物柴油的主要性能指标均符合德国的生物柴油标准。     

生物柴油的超声波辅助固体碱催化制备研究

以精制的山桐子油为原料,固体碱CaO-ZrO为催化剂,在超声波辅助下制备生物柴油。通过单因素实验探讨催化剂用量、醇油物质的量之比、反应温度、超声功率、超声频率、反应时间等因素对生物柴油得率的影响。在此基础上,选取超声功率、催化剂用量、醇油物质的量之比、反应时间4个因素通过正交试验确定最佳工艺条件,即超声功率500 W,催化剂用量3%,醇油物质的量之比10∶1,反应时间60 min。在最佳工艺条件下,生物柴油得率为98.2%,该催化剂具有较好的重复利用性能。     

一种新型菜籽油酯生物柴油的制备

以精制菜籽油、乙二醇单甲醚为原料,以KOH为催化剂,制备出一种含氧量更高的新型生物柴油.采用正交试验研究了反应物配比、催化剂用量、温度、反应时间等因素对产物产率的影响,得出了最佳合成条件,并运用红外光谱与核磁共振法分析了产物的结构.柴油机台架试验表明,燃烧该新型生物柴油后,废气排放大幅度降低.     

利用棉籽油制备二聚酸的副产物开发生物柴油的研究

以棉籽油制备二聚酸的工业副产物为原料,采用对甲苯磺酸作催化剂进行酯化反应制备生物柴油.试验考察了反应条件对酯化率的影响,试验结果表明:在反应温度为75℃,催化剂用量为脂肪酸质量的8%,醇酸物质的量比为3:1的条件下,反应4h,酯化率可以达到97%.反应后对产物进行减压旋转蒸发,回收甲醇和催化剂.该试验操作方便,催化剂活性高,污染小,酯化率高.     

棉籽油乙二醇甲醚酯新型生物柴油的合成

以棉籽油和乙二醇甲醚为原料,KOH为催化剂合成出一种含氧量更高的新型生物柴油。采用正交试验,研究了醇油比、催化剂用量、温度和反应时间四种因素对产物产率的影响,得出了最佳合成条件。运用红外光谱法、核磁共振法、凝胶渗透色谱法对产物结构进行了表征。柴油机台架试验表明,燃烧该新型生物柴油可大幅度减少柴油机的废气排放。     

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。     

棕榈酸叔丁酯的催化制备动力学分析及低温流动性分析

为研究生物柴油低温流动性,以4-二甲氨基吡啶(DMAP)为催化剂,棕榈酸与叔丁醇为原料反应合成棕榈酸叔丁酯。单因素试验分析表明,反应温度为82℃,反应时间为60 min,催化剂用量为10%,醇酸摩尔比为7.5∶1时转化率达到最高,最高转化率为93.10%;正交试验表明,对转化率的主要影响顺序为:反应温度、醇酸摩尔比、催化剂用量、反应时间。反应的最佳条件为:温度87℃,反应时间为60 min,催化剂用量为10%,醇酸摩尔比为10∶1,在此最佳条件下进行验证试验,得到转化率为95.68%;最后,对棕榈酸叔丁酯低温流动性进行了测定及分析。     

响应曲面法优化固体碱催化制备生物柴油的工艺

以固体碱硅酸钠为催化剂进行酯交换反应制备生物柴油,采用响应曲面法中的Box-Behnken模式对影响生物柴油转化率的4个主要因素(温度、催化剂用量、反应时间、醇油物质的量比)进行优化.建立生物柴油转化率的二次多项回归模型方程,并对回归方程系数进行显著性检验和方差分析.试验结果表明:当反应温度为66℃、催化剂用量为大豆油质量的2.1%、反应时间为7h、醇油物质的量比为8.6:1时,生物柴油的转化率最高,最高转化率预测值为75.78%,与实测值基本相符,优化模型有效可靠.     

Biodiesel production from acid oils and ethanol using a solid basic resin as catalyst

In the search of an alternative fuel to substitute diesel fuel, biodiesel appears as one of the most promising sources of energy for diesel engines because of its environmental advantages and also due to the evolution of the petroleum market.Refined oil is the conventional raw material for the production of this biofuel; however, its major disadvantage is the high cost of its production. Therefore, frying oils, waste oils, crude oils and/or acid oils are being tested as alternative raw materials; nevertheless, there will be some problems if a homogeneous basic catalyst (NaOH) is employed due to the high amount of free fatty acid present in the raw oil.In this work, the transesterification reaction of acid oil using solid resin, Dowex monosphere 550 A, was studied as an alternative process. Ethanol was employed to have a natural and sustainable final product. The reaction temperature's effects, the initial amount of free fatty acid, the molar ratio of alcohol/oil and the type of catalyst (homogeneous or heterogeneous) over the main reaction are analyzed and their effects compared.The results obtained show that the solid resin is an alternative catalyst to be used to produce fatty acid ethyl esters (FAEEs) by a transesterification reaction with a final conversion over 90%. On the other hand, the time required to achieve this conversion is bigger than the one required using conventional technology which employs a homogeneous basic catalyst. This reaction time needs to be optimized.     

Biodiesel Production Facilities from Vegetable Oils and Animal Fats

Abstract

Biodiesel is a renewable fuel that can be produced from vegetable oils, animal fats, and used cooking oil including triglycerides. Biodiesel, an alternative biodegradable diesel fuel, is derived from triglycerides by transesterification with methanol and ethanol. Concerns about the depletion of diesel fuel reserves and the pollution caused by continuously increasing energy demands make biodiesel an attractive alternative motor fuel for compression ignition engines. There are four different ways of modifying vegetable oils and fats to use them as diesel fuel, such as pyrolysis (thermal cracking), dilution with hydrocarbons (blending), emulsification and transesterification. The most commonly used process is transesterification of vegetable oils and animal fats. The transesterification reaction is affected by molar ratio of glycerides to alcohol, catalysts, reaction temperature, reaction time and free fatty acids and water content of oils or fats. In the transesterification, free fatty acids and water always produce negative effects, since the presence of free fatty acids and water causes soap formation, consumes catalyst and reduces catalyst effectiveness, all of which result in a low conversion. Biodiesel has over double the price of diesel. The high price of biodiesel is in large part due to the high price of the feedstock.     

A review on biodiesel production using catalyzed transesterification

Biodiesel is a low-emissions diesel substitute fuel made from renewable resources and waste lipid. The most common way to produce biodiesel is through transesterification, especially alkali-catalyzed transesterification. When the raw materials (oils or fats) have a high percentage of free fatty acids or water, the alkali catalyst will react with the free fatty acids to form soaps. The water can hydrolyze the triglycerides into diglycerides and form more free fatty acids. Both of the above reactions are undesirable and reduce the yield of the biodiesel product. In this situation, the acidic materials should be pre-treated to inhibit the saponification reaction. This paper reviews the different approaches of reducing free fatty acids in the raw oil and refinement of crude biodiesel that are adopted in the industry. The main factors affecting the yield of biodiesel, i.e. alcohol quantity, reaction time, reaction temperature and catalyst concentration, are discussed. This paper also described other new processes of biodiesel production. For instance, the Biox co-solvent process converts triglycerides to esters through the selection of inert co-solvents that generates a one-phase oil-rich system. The non-catalytic supercritical methanol process is advantageous in terms of shorter reaction time and lesser purification steps but requires high temperature and pressure. For the in situ biodiesel process, the oilseeds are treated directly with methanol in which the catalyst has been preciously dissolved at ambient temperatures and pressure to perform the transesterification of oils in the oilseeds. This process, however, cannot handle waste cooking oils and animal fats.     

Comparison of performance characteristics of agricultural tractor diesel engine operating on home and industrially produced biodiesel

Owing to unstable diesel fuel prices in the world market, many farmers have been looking for alternative fuels. Vegetable oils are one of the alternatives, which can be used as fuel in diesel engines either in the form of straight vegetable oil or in the form of biodiesel. This study aims to present experimental data by utilization of home and industrial biodiesel as fuel in an agricultural tractor diesel engine. The home biodiesel production was made from different vegetable oils (crude rapeseed, edible sunflower and waste oil) with the process of one‐stage‐based catalyzed transesterification. A commercially available agricultural tractor ZETOR 7745 was employed. Measurements were taken on the power take‐off shaft by electrical dynamometer FROMENT XT200. According to the results, agricultural tractor diesel engine operating on home biodiesel fuels had better performance characteristics related to industrially produced biodiesel and similar to conventional diesel fuel. Copyright © 2009 John Wiley & Sons, Ltd.     

Two-stage processes of homogenous catalysed transesterification of high free fatty acid crude oil of rubber seed

Biodiesel is a diesel replacement and renewable fuel that is manufactured from vegetable oils, animal fats or waste cooking oils. The production of biodiesel from edible oil is currently much more expensive than hydrocarbon-based fuel, due to the relatively high cost of edible oils. The cost of biodiesel can be reduced by using non-edible oils instead of edible oils. The purpose of the present study was to develop a method of esterification of non-edible oil like rubber seed oil (Hevea brasiliensis). The high free fatty acid content oil reacts quickly with alkaline catalysts to form soap, which prevents the separation of biodiesel and glycerol. A two-step process was used instead of the simple alkaline catalysed transesterification process. It consisted of an acid catalysed pre-processing followed by the usual alkaline catalysed process. The physical and chemical properties of biodiesel were analysed. The quantification of methyl esters were done by high-performance liquid chromatography.     

Performance and emissions characteristics of Jatropha oil (preheated and blends) in a direct injection compression ignition engine

The scarce and rapidly depleting conventional petroleum resources have promoted research for alternative fuels for internal combustion engines. Among various possible options, fuels derived from triglycerides (vegetable oils/animal fats) present promising “greener” substitutes for fossil fuels. Vegetable oils, due to their agricultural origin, are able to reduce net CO₂ emissions to the atmosphere along with import substitution of petroleum products. However, several operational and durability problems of using straight vegetable oils in diesel engines reported in the literature, which are because of their higher viscosity and low volatility compared to mineral diesel fuel.In the present research, experiments were designed to study the effect of reducing Jatropha oil’s viscosity by increasing the fuel temperature (using waste heat of the exhaust gases) and thereby eliminating its effect on combustion and emission characteristics of the engine. Experiments were also conducted using various blends of Jatropha oil with mineral diesel to study the effect of reduced blend viscosity on emissions and performance of diesel engine. A single cylinder, four stroke, constant speed, water cooled, direct injection diesel engine typically used in agricultural sector was used for the experiments. The acquired data were analyzed for various parameters such as thermal efficiency, brake specific fuel consumption (BSFC), smoke opacity, CO₂, CO and HC emissions. While operating the engine on Jatropha oil (preheated and blends), performance and emission parameters were found to be very close to mineral diesel for lower blend concentrations. However, for higher blend concentrations, performance and emissions were observed to be marginally inferior.     

The effect of biodiesel fuel obtained from waste frying oil on direct injection diesel engine performance and exhaust emissions

In this study, usage of methyl ester obtained from waste frying oil (WFO) is examined as an experimental material. A reactor was designed and installed for production of methyl ester from this kind of oil. Physical and chemical properties of methyl ester were determined in the laboratory. The methyl ester was tested in a diesel engine with turbocharged, four cylinders and direct injection. Gathered results were compared with No. 2 diesel fuel. Engine tests results obtained with the aim of comparison from the measures of torque, power; specific fuel consumptions are nearly the same. In addition, amount of emission such as CO, CO₂, NO_x, and smoke darkness of waste frying oils are less than No. 2 diesel fuel.     

柴油_渣油和沥青的脉动燃烧对比试验研究

在一变形的里克（Rijke)管中进行了柴油、渣油和沥青的脉动燃烧对比试验。试验发现容易燃烧的 燃料容易激起脉动,难燃燃料由于着火推迟,较难激起脉动,而必须加长尾管长度才能解决问题。当进风面积与燃烧腔截面积之比减小到一定程度时,对于渣油等难燃燃料,其脉动特性会向1／4波长管的脉动特性过渡;而对于柴油等易燃燃料,脉动特性不变。 试验表明,这种无阀脉动燃烧技术可使渣油、沥青等难燃物高效清洁地燃烧,这对于渣油等难燃燃料的利用有重要意义。     

Vegetable oils as renewable fuels for power plants based on low and medium speed diesel engines

There is a high potential for plant oils as alternative fuel for low and medium speed diesel engines, making petroleum-derived fuels likely to be replaced in these types of engines. Vegetable oils have important advantages over both heavy fuel oil (HFO) and marine gas oil (MGO), the fuels currently used in diesel power plants by large two stroke low-speed diesel engines and by medium speed diesel engines, respectively. The emission of certain pollutants and greenhouse gases like SO_x, soot and, mainly, CO₂ can be reduced by using vegetable oils in these types of engines. This work discusses the potential of vegetable oils as fuel for power plant diesel engines and the problems that can be derived from their use. Current experiences with medium speed diesel engines together with the analysis carried out in this paper indicate that vegetable oils can substitute HFO and MGO, without almost any engine modification.