生物燃料生产和技术发展趋势(上)

人们在积极探寻清洁汽、柴油燃料生产新工艺的同时,也在努力开发和利用矿物替代燃料,其中经济性好,对大气污染小的乙醇和生物柴油备受青睬。燃料级乙醇和生物柴油生产正在向低成本方向发展。重点阐述车用燃料乙醇和生物柴油的国内外生产和应用现状以及技术发展趋势。     

生物燃料生产和技术发展趋势(下)

人们在积极探寻清洁汽、柴油燃料生产新工艺的同时,也在努力开发和利用矿物替代燃料,其中经挤性好、对大气污染小的乙醇和生物柴油备受青睐。燃料级乙醇和生物柴油生产正在向低成本方向发展。重点阐述车用燃料乙醇和生物柴油的国内外生产和应用现状以及技术发展趋势。     

后石油时代与生物质液体燃料

进入后石油时代后,生物质液体燃料燃料乙醇和生物柴油受到关注。利用秸秆代替粮食生产燃料乙醇是解决乙醇原料的根本出路,美国正在研究以小麦和大麦秸秆生产燃料乙醇的可行性,我国河南天冠集团已拥有了多项用秸秆生产乙醇的关键技术。标准系列化是我国生物柴油产业做大的关键。     

柴油-生物柴油-乙醇溶解性及其调和燃料特性的研究

以自制的生物柴油为助溶剂,研究了生物柴油对乙醇和柴油调和燃料的助溶作用;研究了不同比例的柴油-生物柴油-乙醇调和燃料的理化特性及稳定性。结果表明,当生物柴油含量为12.55%时,柴油和燃料乙醇可以以任意比例互溶;乙醇含量过高会导致燃料的各种理化性能下降;乙醇含量为10%,生物柴油含量>12.55%为混合燃料较为适宜的调和比列。     

生物燃料的发展前景和展望

(上接第3期第8页)二、发展第二代生物燃料刻不容缓生物柴油和生物乙醇称之为第一代生物燃料。使用生物柴油和生物乙醇仅是解决世界能源问题的第一步。尽管投资在继续增长,但仅依赖基于植物种子和果实的生物柴油和生物乙醇燃料不能解决     

生物柴油特性及作为混合燃料添加剂的研究

论述了生物柴油优越的理化特性,可作为柴油的替代燃料,并讨论了生物柴油作为乙醇（甲醇）与柴油或汽油混合燃料的添加剂情况.通过溶解度测定及三相图实验数据表明生物柴油作为乙醇与柴油添加剂,促溶效果较好;对于生物柴油-汽油-乙醇体系来讲,三者可以任意比例混合,可改善汽油的燃烧性能;对于生物柴油-柴油-甲醇体系,效果不理想.     

原料供应困扰我国生物燃料产业发展

日前中国生物燃料考察组前往美国和巴西，进行了生物燃料技术和市场的应用考察。 通过走访相关部门和企业了解到，目前美国的燃料乙醇生产是以玉米为主要原料，生物柴油则是以转基因大豆为主要原料，其原料供给能够满足生物燃料生产需求；巴西燃料乙醇生产是以甘蔗为原料，生物柴油的原料品种更多，其原料供给适应巴西的自然条件。     

藻类生物燃料：未来生物能源的多样性

分析了以植物为基础的生物燃料的来源,指出了藻类是生物燃料的最有效来源;重点介绍了藻类生物燃料的巨大潜力,如用于生产生物乙醇、生物柴油、生物制氢争沼气等;并讨论了藻类生物燃料的经济可行性和未来的应用前景.     

生物燃料的技术现状及研究趋势分析

生物液体燃料(燃料乙醇、生物柴油、生物丁醇等)是生物能源战略的重要组成部分,世界范围内产业化运作的液体生物燃料主要包括生物柴油和燃料乙醇。重点对生物柴油和纤维素乙醇这两种生物燃料的技术现状和技术研究趋势进行分析。工业生产生物柴油的主要方法是酯交换法,即利用动植物油脂和低碳醇在催化剂的作用下经酯交换反应生成脂肪酸酯。纤维素乙醇技术目前主要研究集中在开发可高效水解新型木质纤维素原料;开发新型温和预处理工艺;开发新型高效纤维素降解酶系;开发木质素高效利用产品;开发乙醇发酵基因工程菌株这五个方面。还对生物柴油和纤维素乙醇的研究趋势进行了方向性的分析。     

生物能源的发展现状及发展前景

主要介绍了生物能源包括燃料乙醇、生物柴油、生物制氢和沼气的原料、生产技术及发展现状。     

生物液体燃料

对全球生物液体燃料的发展现状进行了概述。叙述了目前我国发展燃料乙醇的主要原料以及秸杆乙醇技术。对我国生物柴油产业的发展、生物柴油标准以及影响我国生物柴油发展的因素进行了探讨。并结合我国国情,对如何发展生物液体燃料提出了建议。     

Biodiesel formulations as fuel for internally reforming solid oxide fuel cell

Biodiesel (alkyl ester of rapeseed oil) is prepared using various, methyl, ethyl and butyl alcohols through the transesterification process. Sodium hydroxide and sulfuric acid are used as catalyst for methyl alcohol, ethyl alcohol and butyl alcohol respectively. Biodiesel-water formulations are formulated using water and emulsifiers like sodium lauryl sulphate (SLS) and SPAN 80 in a high shear mixer. The formulations are tested at 800 °C as fuel for internal reforming in solid oxide fuel cells (SOFCs). The formulations based on methyl and butyl esters require the use of emulsifiers to prepare stable emulsions, while ethyl esters are able to form stable emulsions without emulsifiers. The decrease in the biodiesel concentration of formulation does not have any effect on the power density of the ethyl ester formulation. Fuel cells fuelled with 20% formulations lasted longer than 50% formulations in all the formulations tested as result of increase in steam carbon ratio resulting in effective removal of carbon deposited on the anode surface. Butyl ester formulations exhibited the worst performance in both types of formulation tests. The best performance was exhibited by 20% ethyl formulation in terms of life of the cell but 50% methyl ester formulations exhibit the highest power density.     

Effect of the alcohol type used in the production of waste cooking oil biodiesel on diesel performance and emissions

Experimental results were obtained by testing two different alcohol-derived biodiesel fuels: methyl ester and ethyl ester, both obtained from waste cooking oil. These biodiesel fuels were tested pure and blended (30% and 70% biodiesel content, volume basis) with a diesel reference fuel, which was tested too, in a 2.2 l, common-rail injection diesel engine. The operation modes were selected to simulate the European Driving Cycle. Pure biodiesel fuels, compared to the reference fuel, resulted in a slight increase in fuel consumption, in very slight differences in NOx emissions, and in sharp reductions in total hydrocarbon emissions, smoke opacity and particle emissions (both in mass and number), despite the increasing volatile organic fraction of the particulate matter. The type of alcohol used in the production process was found to have a significant effect on the total hydrocarbon emissions and on the particulate matter composition. As the alcohol used was more volatile, both the hydrocarbon emissions and volatile organic fraction of the particulate matter were observed to increase.     

Phase diagrams of mixtures of ethyl palmitate with fatty acid ethyl esters

The cloud point is an important property of biodiesel, controlling its low temperature behaviour, especially the fluidity of the fuel. Although biodiesel is an interesting renewable energy source, data for the melting/cloud point of biodiesel or simple binary or ternary mixtures of fatty acid ethyl esters (FAEE) are still scarce in the literature, particularly for those involving ethyl esters. The phase diagrams of six binary mixtures of ethyl palmitate with saturated and unsaturated fatty acid ethyl esters were determined by Differential Scanning Calorimetry (DSC). The determined systems were successfully described employing the UNIQUAC model. The experimental data indicates that the cloud point is controlled by the fatty acid ethyl ester in the mixture with higher melting temperature.     

Biodiesel CO2 emissions: A comparison with the main fuels in the Brazilian market

The use of biodiesel is increasing as an attractive fuel due to the depleting fossil fuel resources and environmental degradation. This paper presents results of an investigation on the potentials of biodiesel as an alternative fuel and main substitute of diesel oil, comparing the CO₂ emissions of the main fuels in the Brazilian market with those of biodiesel, in pure form or blended in different proportions with diesel oil (2%, 5%, and 20%, called B2, B5, and B20, respectively). The results of the study are shown in ton CO₂ per m³ and ton CO₂ per year of fuel. The fuels were analyzed considering their chemical composition, stoichiometric combustion parameters and mean consumption for a single vehicle. The fuels studied were: gasoline, diesel oil, anhydrous ethyl alcohol (anhydrous ethanol), and biodiesel from used frying oil and from soybean oil. For the case of biodiesel, its complete life cycle and the closed carbon cycle (photosynthesis) were considered. With data provided by the Brazilian Association of Automotive Vehicle Manufacturers (ANFAVEA) for the number of vehicles produced in Brazil, the emissions of CO₂ for the national fleet in 2007 were obtained per type of fuel. With data provided by the Brazilian Department of Transit (DENATRAN) concerning the number of diesel vehicles in the last five years in Brazil, the total CO₂ emissions and the percentage that they would decrease in the case of use of pure biodiesel, B100, or several mixtures, B2, B5 and B20, were calculated. Estimates of CO₂ emissions for a future scenario considering the mixtures B5 and B20 are also included in this article.     

Pilot plant studies of biodiesel production using Brassica carinata as raw material

In recent years, the development of alternative fuels from renewable resources, like biomass, has received considerable attention. Biodiesel is defined as fatty acid methyl or ethyl esters from vegetable oils, when it is used as fuel in diesel engines and heating systems.

In this context, the cultivation of Brassica carinata as oilseed crop for biodiesel production in the south of Europe (Spain and Italy) and north of Africa has gained special interest, since it allows the use of set-aside lands, giving higher yields per hectare than the traditional Spanish crops.

Methyl or ethyl esters are the product of transesterification of vegetable oils with alcohol (methanol/ethanol) using an alkaline catalyst. In addition, the process yields glycerol, which has large applications in the pharmaceutical, food and plastics industries.

In the present work, the process of biodiesel production for pilot plant using B. Carinata oil as raw materials with methanol and using potassium hydroxide as catalyst has been studied.

The biodiesel quality meets European specifications defined by pr EN 14214:2002 (E). The obtained results have been used for industrial scale up of the process.     

Synthesis of biodiesel fuel from safflower oil using various reaction parameters

Biodiesel fuel is gaining more and more importance because of the depletion and uncontrollable prices of fossil fuel resources. The use of vegetable oil and their derivatives as alternatives for diesel fuel is the best answer and as old as Diesel Engine. Chemically biodiesel fuel is the mono alkyl esters of fatty acids derived from renewable feed stocks like vegetable oils and animal fats. Safflower oil contains 75-80% of linoleic acid; the presence of this unsaturated fatty acid is useful in alleviating low temperature properties like pour point, cloud point and cold filter plugging point. In this paper we studied the effect of various parameters such as temperature, molar ratio (oil to alcohol), and concentration of catalyst on synthesis of biodiesel fuel from safflower oil. The better suitable conditions of 1:6 molar ratio (oil to alcohol), 60 degrees C temperature and catalyst concentration of 2% (by wt. of oil) were determined. The finally obtained biodiesel fuel was analyzed for fatty acid composition by GLC and some other properties such as flash point, specific gravity and acid value were also determined. From the results it was clear that the produced biodiesel fuel was with in the recommended standards of biodiesel fuel with 96.8% yield.     

Dependence of biodiesel fuel properties on the structure of fatty acid alkyl esters

Biodiesel, defined as the mono-alkyl esters of vegetable oils or animal fats, is an “alternative” diesel fuel that is becoming accepted in a steadily growing number of countries around the world. Since the source of biodiesel varies with the location and other sources such as recycled oils are continuously gaining interest, it is important to possess data on how the various fatty acid profiles of the different sources can influence biodiesel fuel properties. The properties of the various individual fatty esters that comprise biodiesel determine the overall fuel properties of the biodiesel fuel. In turn, the properties of the various fatty esters are determined by the structural features of the fatty acid and the alcohol moieties that comprise a fatty ester. Structural features that influence the physical and fuel properties of a fatty ester molecule are chain length, degree of unsaturation, and branching of the chain. Important fuel properties of biodiesel that are influenced by the fatty acid profile and, in turn, by the structural features of the various fatty esters are cetane number and ultimately exhaust emissions, heat of combustion, cold flow, oxidative stability, viscosity, and lubricity.