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1.
In this investigation, castor methyl ester (CME) was prepared by transesterification using potassium hydroxide (KOH) as catalyst and was used in four stroke, single cylinder variable compression ratio type diesel engine. Tests were carried out at a rated speed of 1500 rpm at different loads. Straight vegetable oils pose operational and durability problems when subjected to long term usages in diesel engines. These problems are attributed to high viscosity, low volatility and polyunsaturated character of vegetable oils. The process of transesterification is found to be an effective method of reducing vegetable oil viscosity and eliminating operational and durability problems. The important properties of methyl ester of castor seed oil are compared with diesel fuel. The engine performance was analysed with different blends of biodiesel and was compared with mineral diesel. It was concluded that the lower blends of biodiesel increased the break thermal efficiency and reduced the fuel consumption. The exhaust gas temperature increased with increasing biodiesel concentration. The results proved that the use of biodiesel (produced from castor seed oil) in compression ignition engine is a viable alternative to diesel.  相似文献   

2.
Recent concerns over the environment, increasing fuel prices and scarcity of its supply have promoted the interest in development of the alternative sources for petroleum fuels. At present, biodiesel is commercially produced from the refined edible vegetable oils such as sunflower oil, palm oil and soybean oil, etc. by alkaline-catalyzed esterification process. This process is not suitable for production of biodiesel from many unrefined non-edible vegetable oils because of their high acid value. Hence, a two-step esterification method is developed to produce biodiesel from high FFA vegetable oils. The biodiesel production method consists of acid-catalyzed pretreatment followed by an alkaline-catalyzed transesterification. The important properties of methyl esters of rubber seed oil are compared with other esters and diesel. Pure rubber seed oil, diesel and biodiesel are used as fuels in the compression ignition engine and the performance and emission characteristics of the engine are analyzed. The lower blends of biodiesel increase the brake thermal efficiency and reduce the fuel consumption. The exhaust gas emissions are reduced with increase in biodiesel concentration. The experimental results proved that the use of biodiesel (produced from unrefined rubber seed oil) in compression ignition engines is a viable alternative to diesel.  相似文献   

3.
This paper reviews the production and characterization of biodiesel (BD or B) as well as the experimental work carried out by many researchers in this field. BD fuel is a renewable substitute fuel for petroleum diesel or petrodiesel (PD) fuel made from vegetable or animal fats. BD fuel can be used in any mixture with PD fuel as it has very similar characteristics but it has lower exhaust emissions. BD fuel has better properties than that of PD fuel such as renewable, biodegradable, non-toxic, and essentially free of sulfur and aromatics. There are more than 350 oil bearing crops identified, among which only sunflower, safflower, soybean, cottonseed, rapeseed and peanut oils are considered as potential alternative fuels for diesel engines. The major problem associated with the use of pure vegetable oils as fuels, for Diesel engines are caused by high fuel viscosity in compression ignition. Dilution, micro-emulsification, pyrolysis and transesterification are the four techniques applied to solve the problems encountered with the high fuel viscosity. Dilution of oils with solvents and microemulsions of vegetable oils lowers the viscosity, some engine performance problems still exist. The viscosity values of vegetable oils vary between 27.2 and 53.6 mm2/s whereas those of vegetable oil methyl esters between 3.59 and 4.63 mm2/s. The viscosity values of vegetable oil methyl esters highly decreases after transesterification process. Compared to no. 2 diesel fuel, all of the vegetable oil methyl esters were slightly viscous. The flash point values of vegetable oil methyl esters are highly lower than those of vegetable oils. An increase in density from 860 to 885 kg/m3 for vegetable oil methyl esters or biodiesels increases the viscosity from 3.59 to 4.63 mm2/s and the increases are highly regular. The purpose of the transesterification process is to lower the viscosity of the oil. The transesterfication of triglycerides by methanol, ethanol, propanol and butanol, has proved to be the most promising process. Methanol is the commonly used alcohol in this process, due in part to its low cost. Methyl esters of vegetable oils have several outstanding advantages among other new-renewable and clean engine fuel alternatives. The most important variables affecting the methyl ester yield during the transesterification reaction are molar ratio of alcohol to vegetable oil and reaction temperature. Biodiesel has become more attractive recently because of its environmental benefits. Biodiesel is an environmentally friendly fuel that can be used in any diesel engine without modification.  相似文献   

4.
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.  相似文献   

5.
Progress in biodiesel processing   总被引:3,自引:0,他引:3  
Biodiesel is a notable alternative to the widely used petroleum-derived diesel fuel since it can be generated by domestic natural sources such as soybeans, rapeseeds, coconuts, and even recycled cooking oil, and thus reduces dependence on diminishing petroleum fuel from foreign sources. The injection and atomization characteristics of the vegetable oils are significantly different than those of petroleum-derived diesel fuels, mainly as the result of their high viscosities. Modern diesel engines have fuel-injection system that is sensitive to viscosity change. One way to avoid these problems is to reduce fuel viscosity of vegetable oil in order to improve its performance. The conversion of vegetable oils into biodiesel is an effective way to overcome all the problems associated with the vegetable oils. Dilution, micro-emulsification, pyrolysis, and transesterification are the four techniques applied to solve the problems encountered with the high fuel viscosity. Transesterification is the most common method and leads to monoalkyl esters of vegetable oils and fats, now called biodiesel when used for fuel purposes. The methyl ester produced by transesterification of vegetable oil has a high cetane number, low viscosity and improved heating value compared to those of pure vegetable oil which results in shorter ignition delay and longer combustion duration and hence low particulate emissions.  相似文献   

6.
Vegetables oils are simplest route of biofuel utilization in direct injection compression ignition (DICI) engines however several operational and durability problems are encountered while using straight vegetable oils in CI engines due to their high viscosity and low volatility. Reduction of viscosity by blending or exhaust gas heating leads to savings in chemical processing cost incurred on transesterification. In this experimental study, performance, emission and combustion characteristics of Karanja oil blends (K10, K20, K50 and K100) with mineral diesel were investigated in unheated conditions in a direct injection CI engine at different engine loads and constant engine speed (1500 rpm) vis-à-vis baseline data from mineral diesel. Analysis of performance parameters such as brake specific fuel consumption (BSFC), thermal efficiency, and exhaust gas temperature; mass emissions of various gaseous pollutant species; combustion parameters such as in-cylinder pressure rise, instantaneous heat release and cumulative heat release etc. were carried out. Detailed combustion analysis revealed that the combustion duration increased significantly even with smaller concentration of Karanja oil in the fuel blend. HC, CO and Smoke emissions were found to decrease for 20–50% (v/v) Karanja oil content in the fuel blends.  相似文献   

7.
The use of vegetable oils as a fuel in diesel engines causes some problems due to their high viscosity compared with conventional diesel fuel. Various techniques and methods are used to solve the problems resulting from high viscosity. One of these techniques is fuel blending. In this study, a blend of 50% sesame oil and 50% diesel fuel was used as an alternative fuel in a direct injection diesel engine. Engine performance and exhaust emissions were investigated and compared with the ordinary diesel fuel in a diesel engine. The experimental results show that the engine power and torque of the mixture of sesame oil–diesel fuel are close to the values obtained from diesel fuel and the amounts of exhaust emissions are lower than those of diesel fuel. Hence, it is seen that blend of sesame oil and diesel fuel can be used as an alternative fuel successfully in a diesel engine without any modification and also it is an environmental friendly fuel in terms of emission parameters.  相似文献   

8.
K Pramanik   《Renewable Energy》2003,28(2):239-248
In the present investigation the high viscosity of the jatropha curcas oil which has been considered as a potential alternative fuel for the compression ignition (C.I.) engine was decreased by blending with diesel. The blends of varying proportions of jatropha curcas oil and diesel were prepared, analyzed and compared with diesel fuel. The effect of temperature on the viscosity of biodiesel and jatropha oil was also studied. The performance of the engine using blends and jatropha oil was evaluated in a single cylinder C.I. engine and compared with the performance obtained with diesel. Significant improvement in engine performance was observed compared to vegetable oil alone. The specific fuel consumption and the exhaust gas temperature were reduced due to decrease in viscosity of the vegetable oil. Acceptable thermal efficiencies of the engine were obtained with blends containing up to 50% volume of jatropha oil. From the properties and engine test results it has been established that 40–50% of jatropha oil can be substituted for diesel without any engine modification and preheating of the blends.  相似文献   

9.
In order to meet the energy requirements, there has been growing interest in alternative fuels like biodiesels, methyl alcohol, ethyl alcohol, biogas, hydrogen and producer gas to provide a suitable diesel oil substitute for internal combustion engines. Vegetable oils present a very promising alternative to diesel oil since they are renewable and have similar properties. Vegetable oils offer almost the same power output with slightly lower thermal efficiency when used in diesel engine [Srivastava A, Prasad R. Triglycerides-based diesel fuels. Renew Sustain Energy Rev 2000;4:111–33. [1]; Vellguth G. Performance of vegetable oils and their monoesters as fuels for diesel engines. SAE 831358, 1983. [2]; Demirbas A. Biodiesel production from vegetable oils via catalytic and non-catalytic supercritical methanol transesterification methods. Int J Prog Energy Combust Sci 2005;31:466–87. [3]; Jajoo BN, Keoti RS. Evaluation of vegetable oils as supplementary fuels for diesel engines. In: Proceedings of the XV national conference on IC engines and combustion, Anna University Chennai, 1997. [4]; Altin R, Cetinkaya S, Yucesu HS. The potential of using vegetable oil fuels as fuel for diesel engines. Int J Energy Convers Manage 2000;42:529–38, 248. [5]; Gajendra Babu MK, Chandan Kumar Das LM. Experimental investigations on a Karanja oil methyl ester fuelled DI diesel engine. SAE 2006-01-0238, 2006. [6]; Agarwal D, Kumar Agarwal A. Performance and emission characteristics of a Jatropha oil (preheated and blends) in a direct injection compression ignition engine. Int J Appl Therm Eng 2007;27:2314–23. [7]]. Research in this direction with edible oils have yielded encouraging results, but their use as fuel for diesel engine has limited applications due to higher domestic requirement [Scholl Kyle W, Sorenson Spencer C. Combustion Analysis of soyabean oil methyl ester in a direct injection diesel engine. SAE 930934, 1993. [8]; Nwafor OMI. Effect of advanced injection timing on the performance of rapeseed oil in diesel engines. Int J Renew Energy 2000;21:433–44. [9]; Nwafor OMI. The effect of elevated fuel inlet temperature on performance of diesel engine running on neat vegetable oil at constant speed conditions. Renew Energy 2003;28:171–81. [10]]. In view of this, Honge oil (Pongamia Pinnata Linn) being non-edible oil could be regarded as an alternative fuel for CI engine applications. The viscosity of Honge oil is reduced by transesterification process to obtain Honge oil methyl ester (HOME).Gasification is a process in which solid biomass is converted into a mixture of combustible gases, which complete their combustion in an IC engine. Hence, producer gas can act as a promising alternative fuel, especially for diesel engines by substituting considerable amount of diesel fuels. Downdraft moving bed gasifiers coupled with IC engine are a good choice for moderate quantities of available biomass, up to 500 kW of electric power. Hence, bioderived gas and vegetable liquids appear more attractive in view of their friendly environmental nature. Since vegetable oils produce higher smoke emissions, dual fuel operation could be adopted for improving their performance.  相似文献   

10.
Abstract

The purpose of this work is to investigate biodiesel production processes from vegetable oils. Biodiesel fuel can be made from new or used vegetable oils and animal fats, which are non-toxic, biodegradable, renewable resources. The vegetable oil fuels were not acceptable because they were more expensive than petroleum fuels. Biodiesel has become more attractive recently because of its environmental benefits. With recent increases in petroleum prices and uncertainties concerning petroleum availability, there is renewed interest in vegetable oil fuels for diesel engines. Dilution of oils with solvents and microemulsions of vegetable oils lowers the viscosity, and some engine performance problems still exist. The purpose of the transesterification process is to lower the viscosity of the oil. Pyrolysis produces more biogasoline than biodiesel fuel.  相似文献   

11.
Fuel crisis because of dramatic increase in vehicular population and environmental concerns have renewed interest of scientific community to look for alternative fuels of bio-origin such as vegetable oils. Vegetable oils can be produced from forests, vegetable oil crops, and oil bearing biomass materials. Non-edible vegetable oils such as linseed oil, mahua oil, rice bran oil, etc. are potentially effective diesel substitute. Vegetable oils have high-energy content. This study was carried out to investigate the performance and emission characteristics of linseed oil, mahua oil, rice bran oil and linseed oil methyl ester (LOME), in a stationary single cylinder, four-stroke diesel engine and compare it with mineral diesel. The linseed oil, mahua oil, rice bran oil and LOME were blended with diesel in different proportions. Baseline data for diesel fuel was collected. Engine tests were performed using all these blends of linseed, mahua, rice bran, and LOME. Straight vegetable oils posed operational and durability problems when subjected to long-term usage in CI engine. These problems are attributed to high viscosity, low volatility and polyunsaturated character of vegetable oils. However, these problems were not observed for LOME blends. Hence, process of transesterification is found to be an effective method of reducing vegetable oil viscosity and eliminating operational and durability problems. Economic analysis was also done in this study and it is found that use of vegetable oil and its derivative as diesel fuel substitutes has almost similar cost as that of mineral diesel.  相似文献   

12.
Vegetable oil is one of the main first generation liquid biofuels. The fuel characteristics of vegetable oil such as viscosity and atomization cannot be accommodated by existing diesel engines. An alternate process has been developed to improve the fuel characteristics of vegetable oils through the process of alcoholysis to produce a fuel called biodiesel. It can be used in engines as substitute for fossil fuel. This paper reviews the characteristics of different oils available for biodiesel production and the production technologies, engine performance using vegetable oil and biodiesel, and emission studies. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

13.

Biodiesel from transesterification of vegetable oils is an excellent alternative fuel. There is, however, a need to develop a direct process for conversion of vegetable oils into gasoline-competitive biodiesel and other petroleum products. Methyl esters of vegetable oils have several outstanding advantages among other new-renewable and clean engine fuel alternatives. The purpose of the transesterification process is to lower the viscosity of vegetable oil. Compared to No. 2 diesel fuel, all of the vegetable oils are much more viscous, whereas methyl esters of vegetable oils are slightly more viscous. The methyl esters are more volatile than those of the vegetable oils. Conversion of vegetable oils to useful fuels involves the pyrolysis and catalytic cracking of the oils into lower molecular products. Pyrolysis produces more biogasoline than biodiesel fuel. Soap pyrolysis products of vegetable oils can be used as alternative diesel engine fuel. The soaps obtained from the vegetable oils can be pyrolyzed into hydrocarbon-rich products. Zinc chloride catalyst contributed greatly to high amounts of hydrocarbons in the liquid product. The yield of ZnCl 2 catalytic conversion of the soybean oil reached the maximum 79.9% at 660 K.  相似文献   

14.
As an alternative fuel for compression ignition engines, plant oils are in principle renewable and carbon-neutral. However, their use raises technical, economic and environmental issues. A comprehensive and up-to-date technical review of using both edible and non-edible plant oils (either pure or as blends with fossil diesel) in CI engines, based on comparisons with standard diesel fuel, has been carried out. The properties of several plant oils, and the results of engine tests using them, are reviewed based on the literature. Findings regarding engine performance, exhaust emissions and engine durability are collated. The causes of technical problems arising from the use of various oils are discussed, as are the modifications to oil and engine employed to alleviate these problems. The review shows that a number of plant oils can be used satisfactorily in CI engines, without transesterification, by preheating the oil and/or modifying the engine parameters and the maintenance schedule. As regards life-cycle energy and greenhouse gas emission analyses, these reveal considerable advantages of raw plant oils over fossil diesel and biodiesel. Typical results show that the life-cycle output-to-input energy ratio of raw plant oil is around 6 times higher than fossil diesel. Depending on either primary energy or fossil energy requirements, the life-cycle energy ratio of raw plant oil is in the range of 2–6 times higher than corresponding biodiesel. Moreover, raw plant oil has the highest potential of reducing life-cycle GHG emissions as compared to biodiesel and fossil diesel.  相似文献   

15.
Renewable fuels produced from vegetable oils are an attractive alternative to fossil-based fuel. Different type of fuels can be derived from these triglycerides. One of them is biodiesel which is a mono alkyl ester of the vegetable oil. The biodiesel is produced by transesterification of the oil with an alcohol in the presence of a catalyst. Another kind of fuel (which is similar to petroleum-derived diesel) can be produced from the vegetable oil using hydroprocessing technique. This method uses elevated temperature and pressure along with a catalyst to produce a fuel termed as ‘renewable diesel’. The fuel produced has properties that are beneficial for the engine as well as the environment. It has high cetane number, low density, excellent cold flow properties and same materials can be used as are used for engine running on petrodiesel. It can effectively reduce NOx, PM, HC, CO emissions and unregulated emissions as well as greenhouse gases as compared to diesel. The fuel is also beneficial for the after-treatment systems. Trials in the field have shown that the volumetric fuel consumption of renewable diesel is higher than petrodiesel and nearly proportional to the volumetric heating value. The present review focuses on the hydroprocessing technique used for the renewable diesel production and the effect of different parameters such as catalyst, reaction temperature, hydrogen pressure, liquid hourly space velocity (LHSV) and H2/oil ratio on oil conversion, diesel selectivity, and isomerization. The review also summarizes the effect; renewable diesel has on combustion, performance, and emission characteristics of a compression ignition engine.  相似文献   

16.

Numerous studies indicated that oil sources in the world will come to an end. As a result, new alternative energy sources will be required to substitute for oil. Some of the experimental studies showed that vegetable oil can be used as alternative fuel in diesel engines. The viscosity of vegetable oil is much higher than that of standard diesel fuel; therefore, the high viscosity of the vegetable oil can cause problems for injection systems and engine components. To decrease viscosity, cottonseed methyl ester was obtained from raw cottonseed oil by transesterification method. In this study, cottonseed methyl ester was used in a four-stroke, single cylinder, and air-cooled diesel engine as alternative fuel. Engine tests carried out at full load-different speed range, the engine torque and power of cottonseed oil methyl ester was found to be lower than that of diesel fuel in the range of 3–9% and specific fuel consumption was higher than that of diesel fuel by approximately 8–10%. CO 2 , CO, and NO x emissions of cottonseed methyl ester were lower than that of diesel fuel.  相似文献   

17.
《Applied Thermal Engineering》2007,27(13):2314-2323
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.  相似文献   

18.
Methyl and ethyl esters as biodiesel fuels were prepared from linseed oil with transesterification reaction in non-catalytic supercritical fluids conditions. Biodiesel fuel is a renewable substitute fuel for petroleum diesel fuel made from vegetable or animal fats. Biodiesel fuel has better properties than that of petroleum diesel fuel such as renewable, biodegradable, non-toxic, and essentially free of sulfur and aromatics. The purpose of the transesterification process is to lower the viscosity of the oil. The viscosity values of linseed oil methyl and ethyl esters highly decreases after transesterification process. The viscosity values of vegetable oils vary between 27.2 and 53.6 mm2 s?1, whereas those of vegetable oil methyl esters between 3.59 and 4.63 mm2 s?1. Compared with no. 2 diesel fuel, all of the vegetable oil methyl esters were slightly viscous. The flash point values of vegetable oil methyl esters are highly lower than those of vegetable oils. The transesterification of linseed oil in supercritical fluids such as methanol and ethanol has proved to be the most promising process. Methanol is the commonly used alcohol in this process, due in part to its low cost. Methyl esters of vegetable oils have several outstanding advantages among other new-renewable and clean engine fuel alternatives. The most important variables affecting the methyl ester yield during the transesterification reaction are molar ratio of alcohol to vegetable oil and reaction temperature. Biodiesel has become more attractive recently because of its environmental benefits. Biodiesel is an environmentally friendly fuel that can be used in any diesel engine without modification.  相似文献   

19.
In order to verify and solve the problem of NOx and PM emissions, it is necessary to directly observe the internal combustion chamber of a diesel engine. Many studies have been performed in recent years to verify the macroscopic and microscopic behavior of the injected fuel spray because observing it is not easy due to the difficulties of the experiment. Researchers have investigated the spray characteristics for various diesel injector nozzles over a wide range of temperatures and pressure, but there is lack of evaluation for the spray characteristics for biodiesel. At a time when rapid rise of fuel prices and depleting hydrocarbon resources of the world have forced us to look for alternative fuels biodiesel produced by transesterification of non-edible vegetable oils is promising to be an important additive/substitute to petro diesel. Biodiesel being an oxygenated and sulfur-free fuel leads to more complete combustion and lower emissions. But, the energy content or net calorific value of biodiesel is less than that of diesel fuel; also it has higher viscosity and density, than diesel fuel. A considerable improvement in these properties can be obtained by mixing diesel and biodiesel and then using the blends. Biodiesel and biodiesel/petro diesel blends, with their higher lubricity levels, are increasingly being utilized as an alternative. Present paper analyzed the correlation of injection parameters that will affect the spray characteristics of biodiesel. Observations for analyzing the effect of injection parameters on spray cone angle, break up length and fuel penetration were made. Finally the performance and emissions tests were studied. Atomization and vaporization of fuel are greatly influenced by viscosity and density of fuel and these properties are temperature dependent. Thus fuel inlet temperature plays a very important role in fuel atomization process. At higher temperature viscosity of fuel decreases which enhances the atomization of biofuels.  相似文献   

20.
The present article elaborates on the various emission characteristics of mahua oil with diesel fuel in a diesel engine at various blending conditions. Experimental investigation results are studied for various parameters such as exhaust emission of carbon monoxide (CO), hydrocarbon (HC), and oxides of nitrogen (NO) gases and exhaust gas temperature. Results show that residual oxygen, CO, HC, and NO emission were the lowest for mahua biodiesel compared with diesel. The experimental results proved that the use of mahua oil biodiesel as fuel in the diesel engine is a viable alternative to diesel fuel. Mahua biodiesel oil may be beneficial in decreasing greenhouse gas emissions without any engine modification. Mahua oil has the possibility of becoming a sustainable fuel source as biodiesel.  相似文献   

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