生物柴油燃料特性的研究

植物油及其衍生物被用作柴油的代用燃料,其中甲酯被定义为“生物柴油“.燃用生物柴油可降低汽车尾气中有害排放物HC,CO和颗粒物PM的浓度,降低CO2的净排放量.文章着重讨论了生物柴油的热值,CN,IV和低温流动性等参数,认为不饱和双键的数目和位置对燃油品质的影响极大.     

生物柴油的理化特性对柴油机性能的影响研究

对比分析了生物柴油与矿物柴油的燃料特性、柴油机燃用生物柴油对柴油机各种性能的影响及燃用生物柴油的优劣。结果表明：作为代用燃料,生物柴油与柴油的理化特性相接近,并且具有发火性好,安全性高,对发动机腐蚀性小等优点,但其热值和蒸发性能不如矿物柴油。燃用生物柴油后柴油机动力性和经济性略有下降,HC,CO排放大幅下降,NOx排放略有增加,且对柴油机各性能的影响程度随生物柴油掺烧比例的增大而增加。     

压燃发动机燃用不同原料生物柴油的燃烧与排放特性

利用KIVA3数值模拟研究柴油以及三种生物柴油(大豆油甲酯、棕榈油甲酯、麻疯油甲酯)对压燃发动机燃烧和排放性能的影响。数值计算结果表明:生物柴油在燃烧初始阶段与柴油燃烧特性基本一致,燃烧中后期,生物柴油的平均缸温低于柴油,其中麻疯油甲酯最为明显;生物柴油碳烟和CO生成量明显低于柴油。生物柴油虽然缸内氧含量比柴油高,但由于受缸温的影响,NOx排放比柴油低,而麻疯油甲酯在三种生物柴油中NOx排放最低。     

喷油持续期对生物柴油发动机排放影响的仿真分析

利用质谱联用仪检测酸化大豆油甲酯的组分,基于检测结果计算其热物性参数。利用KIVA3V模拟研究135柴油机燃用柴油和纯生物柴油的燃烧和排放,并研究喷油持续期对其影响。结果表明相同功率条件下,生物柴油的油耗率比柴油大,但是随着喷油持续期的增大,油耗率差别减小;最大缸温Tmax和最大缸压Pmax均高于柴油,并随着喷油持续期的增大,出现的时刻推迟;CO和soot排放均低于柴油,而且随喷油持续期的增大排放差距增大;NOx排放高于柴油,但随着喷油持续期的增大,NOx的增加量降低。另外,喷油持续期对柴油和生物柴油燃烧和排放的变化趋势有着不同的影响。     

国外三种柴油代用燃料的燃烧与排放特性

能够直接应用于现有柴油机上且对其结构无需改造的代用燃料在使用、存储、分配方面具有明显优势,本文将述及的FT燃油、植物油甲脂RME和生物柴油BIO就是这样的柴油代用燃料.本文将分别介绍这三种燃料用于柴油机时对原机效率和排放的影响.     

燃料甲酯应用研究初探

本文介绍了燃料甲酯用于发动机台架试验的情况。燃料甲酯是利用植物油脚料提炼而成，其主要理论性质与０号柴油相近。初步试验结果表明：燃料甲酯用作柴油机代用燃料时，由于其热值稍低而使比油耗相应略高之外，在其它性能方面均与烧柴油时大体上相当，且可与柴油以任意比例掺合。另外从代用燃料角度而言，甲酯与甲醇与良好的互溶性，可掺合作燃料而不需采用特殊措施，此是优于柴油掺甲醇之处。燃料甲酯用于汽油机时可作为甲醇汽油的     

柴油机燃用生物柴油-乙醇-水微乳化燃料性能研究

为研究生物柴油-乙醇-水微乳化燃料在柴油机上的应用,在单缸直喷式柴油机上,对生物柴油和生物柴油-乙醇-水微乳化燃料的燃烧特性、经济性和排放进行试验研究。研究结果表明:与生物柴油相比,生物柴油-乙醇-水微乳化燃料的压力、压力升高率及放热率曲线明显后移;峰值燃烧压力和峰值瞬时燃烧放热率增加,燃烧更加完全、放热更加集中;瞬时燃烧放热率第二峰值明显降低,瞬时燃烧放热率曲线型心转角在中高负荷更加靠近上止点,循环等容度和有效效率明显提高;燃料消耗率增加而比能耗略有降低;NOx和烟度排放明显降低。研究结果表明:生物柴油-乙醇-水微乳化燃料是节能、环保的柴油机代用燃料。     

共轨柴油机燃用天然气合成油的性能与排放特性

对某共轨柴油机燃用天然气合成油(gas-to-liquids,GTL柴油)和国-Ⅲ柴油进行了动力性、燃油经济性和排放特性研究.结果表明:与国-Ⅲ柴油相比,共轨柴油机燃用GTL柴油时的动力性与国-Ⅲ柴油相当,燃油消耗率降低约4%,GTL 柴油的 HC、CO、Nox、PM 排放分别降低17%、8%、3%、40%,烟度排放降低35%.GTL 柴油明显改善柴油机HC和烟度排放,并能同时降低柴油机Nox和 PM 排放,是一种潜力巨大的低排放柴油清洁代用燃料.     

生物柴油--汽车的清洁代用燃料

文章主要介绍了生物柴油的生产工艺、与石油柴油以及其它代用燃料的性能比较、作为发动机燃料的优点、生物柴油发动机对空气污染物排放的影响以及应用时尚需解决的问题。最后探讨了我国发展生物柴油的意义及其技术的研究状况。     

柴油机代用燃料生物柴油和二甲醚的应用现状和发展前景

本文论述了我国发展生物柴油和二甲醚燃料的必要性,并分析了生物柴油和二甲醚作为柴油机代用燃料的优势和不利因素,详细阐述了目前柴油机燃用生物柴油和二甲醚燃料的研究应用现状,指出今后发动机代用燃料的发展方向.     

6BTA 5.9 G2-1 Cummins engine performance and emission tests using methyl ester mahua (Madhuca indica) oil/diesel blends

Neat mahua oil poses some problems when subjected to prolonged usage in CI engine. The transesterification of mahua oil can reduce these problems. The use of biodiesel fuel as substitute for conventional petroleum fuel in heavy-duty diesel engine is receiving an increasing amount of attention. This interest is based on the properties of bio-diesel including the fact that it is produced from a renewable resource, its biodegradability and potential to exhaust emissions. A Cummins 6BTA 5.9 G2- 1, 158 HP rated power, turbocharged, DI, water cooled diesel engine was run on diesel, methyl ester of mahua oil and its blends at constant speed of 1500 rpm under variable load conditions. The volumetric blending ratios of biodiesel with conventional diesel fuel were set at 0, 20, 40, 60, and 100. Engine performance (brake specific fuel consumption, brake specific energy consumption, thermal efficiency and exhaust gas temperature) and emissions (CO, HC and NOx) were measured to evaluate and compute the behavior of the diesel engine running on biodiesel. The results indicate that with the increase of biodiesel in the blends CO, HC reduces significantly, fuel consumption and NOx emission of biodiesel increases slightly compared with diesel. Brake specific energy consumption decreases and thermal efficiency of engine slightly increases when operating on 20% biodiesel than that operating on diesel.     

Experimental investigation of control of NOx emissions in biodiesel-fueled compression ignition engine

Biodiesel is an alternative fuel consisting of the alkyl esters of fatty acids from vegetable oils or animal fats. Vegetable oils are produced from numerous oil seed crops (edible and non-edible), e.g., rapeseed oil, linseed oil, rice bran oil, soybean oil, etc. Research has shown that biodiesel-fueled engines produce less carbon monoxide (CO), unburned hydrocarbon (HC), and particulate emissions compared to mineral diesel fuel but higher NO_x emissions. Exhaust gas recirculation (EGR) is effective to reduce NO_x from diesel engines because it lowers the flame temperature and the oxygen concentration in the combustion chamber. However, EGR results in higher particulate matter (PM) emissions. Thus, the drawback of higher NO_x emissions while using biodiesel may be overcome by employing EGR. The objective of current research work is to investigate the usage of biodiesel and EGR simultaneously in order to reduce the emissions of all regulated pollutants from diesel engines. A two-cylinder, air-cooled, constant speed direct injection diesel engine was used for experiments. HCs, NO_x, CO, and opacity of the exhaust gas were measured to estimate the emissions. Various engine performance parameters such as thermal efficiency, brake specific fuel consumption (BSFC), and brake specific energy consumption (BSEC), etc. were calculated from the acquired data. Application of EGR with biodiesel blends resulted in reductions in NO_x emissions without any significant penalty in PM emissions or BSEC.     

Biodiesel production from inedible animal tallow and an experimental investigation of its use as alternative fuel in a direct injection diesel engine

In this study, a substitute fuel for diesel engines was produced from inedible animal tallow and its usability was investigated as pure biodiesel and its blends with petroleum diesel fuel in a diesel engine. Tallow methyl ester as biodiesel fuel was prepared by base-catalyzed transesterification of the fat with methanol in the presence of NaOH as catalyst. Fuel properties of methyl ester, diesel fuel and blends of them (5%, 20% and 50% by volume) were determined. Viscosity and density of fatty acid methyl ester have been found to meet ASTM D6751 and EN 14214 specifications. Viscosity and density of tallow methyl esters are found to be very close to that of diesel. The calorific value of biodiesel is found to be slightly lower than that of diesel. An experimental study was carried out in order to investigate of its usability as alternative fuel of tallow methyl ester in a direct injection diesel engine. It was observed that the addition of biodiesel to the diesel fuel decreases the effective efficiency of engine and increases the specific fuel consumption. This is due to the lower heating value of biodiesel compared to diesel fuel. However, the effective engine power was comparable by biodiesel compared with diesel fuel. Emissions of carbon monoxide (CO), oxides of nitrogen (NO_x), sulphur dioxide (SO₂) and smoke opacity were reduced around 15%, 38.5%, 72.7% and 56.8%, respectively, in case of tallow methyl esters (B100) compared to diesel fuel. Besides, the lowest CO, NO_x emissions and the highest exhaust temperature were obtained for B20 among all other fuels. The reductions in exhaust emissions made tallow methyl esters and its blends, especially B20 a suitable alternative fuel for diesel and thus could help in controlling air pollution. Based on this study, animal tallow methyl esters and its blends with petroleum diesel fuel can be used a substitute for diesel in direct injection diesel engines without any engine modification.     

Hydrogen addition to tea seed oil biodiesel: Performance and emission characteristics

Compression ignition engines are the dominant tools of the modern human life especially in the field of transportation. But, the increasing problematic issues such as decreasing reserves and environmental effects of diesel fuels which is the energy source of compression ignition engines forcing researchers to investigate alternative fuels for substitution or decreasing the dependency on fossil fuels. The mostly known alternative fuel is biodiesel fuel and many researchers are investigating the possible raw materials for biodiesel production. Also, hydrogen fuel is an alternative fuel which can be used in compression ignition engines for decreasing fuel consumption and hazardous exhaust emissions by enriching the fuel. In this study, influences of hydrogen enrichment to diesel and diesel tea seed oil biodiesel blends (B10 and B20) were investigated on an unmodified compression ignition engine experimentally. In consequence of the experiments, lower torque and higher brake specific fuel consumption data were measured when the engine was fuelled diesel biodiesel blends (B10 and B20) instead of diesel fuel. Also, diesel biodiesel blends increased CO₂ and NO_x emissions while decreasing the CO emissions. Hydrogen enrichment (5 l/m and 10 l/m) was improved the both torque and brake specific fuel consumption for all test fuels. Furthermore, hydrogen enrichment reduced CO and CO₂ emissions due to absence of carbon atoms in the chemical structure for all test fuels. Increasing flow rate of hydrogen fuel from 5 l/m to 10 l/m further improved performance measures and emitted harmful gases except NO_x. The most significant drawback of the hydrogen enrichment was the increased NO_x emissions.     

Comparative study of biodiesel from Jatropha and orange peel oils as pilot fuels in a dual-fuel engine

The diesel-like properties of biodiesel make it a good alternative for CI engines. In the present work, the scope of biodiesel as a pilot fuel has been studied and compared with diesel. The results show that the use of Jatropha oil methyl ester (JOME) and orange peel oil methyl ester (OPOME) as pilot fuel improves BTE and BSFC of dual-fuel engines compared to diesel as a pilot fuel. The use of JOME and OPOME as a pilot fuel for CNG also decreases the emissions like unburnt hydrocarbons, CO, and smoke. However, NO_X emissions increase at higher load. In contrast, use of biodiesel as pilot fuel improves the performance and emissions characteristics of dual-fuel engines.     

A study on the performance and emission of a diesel engine fueled with Jatropha biodiesel oil and its blends

Biodiesel either in neat form or as a mixture with diesel fuel is widely investigated to solve the twin problem of depletion of fossil fuels and environmental degradation. The main objective of the present study is to compare performance, emission and combustion characteristics of biodiesel derived from non edible Jatropha oil in a dual fuel diesel engine with base line results of diesel fuel. The performance parameters evaluated were: brake thermal efficiency, brake specific fuel consumption, power output. As a part of combustion study, in-cylinder pressure, rate of pressure rise and heat release rates were evaluated. The emission parameters such as carbon monoxide, carbon dioxide, un-burnt hydrocarbon, oxides of nitrogen and smoke opacity with the different fuels were also measured and compared with base line results. The different properties of Jatropha oil after transestrification were within acceptable limits of standards as set by many countries. The brake thermal efficiency of Jatropha methyl ester and its blends with diesel were lower than diesel and brake specific energy consumption was found to be higher. However, HC, CO and CO₂ and smoke were found to be lower with Jatropha biodiesel fuel. NO_x emissions on Jatropha biodiesel and its blend were higher than Diesel. The results from the experiments suggest that biodiesel derived from non edible oil like Jatropha could be a good substitute to diesel fuel in diesel engine in the near future as far as decentralized energy production is concerned. In view of comparable engine performance and reduction in most of the engine emissions, it can be concluded and biodiesel derived from Jatropha and its blends could be used in a conventional diesel engine without any modification.     

Performance, emission and combustion characteristics of biodiesel fuelled variable compression ratio engine

Experiments has been carried out to estimate the performance, emission and combustion characteristics of a single cylinder; four stroke variable compression ratio multi fuel engine fuelled with waste cooking oil methyl ester and its blends with standard diesel. Tests has been conducted using the fuel blends of 20%, 40%, 60% and 80% biodiesel with standard diesel, with an engine speed of 1500 rpm, fixed compression ratio 21 and at different loading conditions. The performance parameters elucidated includes brake thermal efficiency, specific fuel consumption, brake power, indicated mean effective pressure, mechanical efficiency and exhaust gas temperature. The exhaust gas emission is found to contain carbon monoxide, hydrocarbon, nitrogen oxides and carbon dioxide. The results of the experiment has been compared and analyzed with standard diesel and it confirms considerable improvement in the performance parameters as well as exhaust emissions. The blends when used as fuel results in the reduction of carbon monoxide, hydrocarbon, carbon dioxide at the expense of nitrogen oxides emissions. It has found that the combustion characteristics of waste cooking oil methyl ester and its diesel blends closely followed those of standard diesel.     

Fuel properties and exhaust emissions of low blending rate soybean oil methyl esters blended with diesel fuel

The main properties and engine emissions of low blending rate soybean oil methyl ester blended with diesel from 5 to 30 wt% were compared and analyzed. The experimental results show that, compared with diesel fuel, with an increase in the soybean oil methyl ester percentage in the blends, distillation temperature at 50%, flash point, kinematic viscosity, specific gravity, gelatine content, carbon residue, acidity and ash increase while a cold filter plugging point, solidifying point and copper corrosion keep constant, sulfur content decreases, smoke density and HC decrease while NO_x emission increase, CO increases at 2,200 r/min but decreases at 3,400 r/min.     

An experimental study on performance and exhaust emissions of a diesel engine fuelled with tobacco seed oil methyl ester

Tobacco seeds are a by product of tobacco leaves production. To the author’s best knowledge, unlike tobacco leaves, tobacco seeds are not collected from fields and are not commercial products. However, tobacco seeds contain significant amounts of oil. Although tobacco seed oil is a non-edible vegetable oil, it can be utilized for biodiesel production as a new renewable alternative diesel engine fuel. In this study, an experimental study on the performance and exhaust emissions of a turbocharged indirect injection diesel engine fuelled with tobacco seed oil methyl ester was performed at full and partial loads. The results showed that the addition of tobacco seed oil methyl ester to the diesel fuel reduced CO and SO₂ emissions while causing slightly higher NO_x emissions. Meanwhile, it was found that the power and the efficiency increased slightly with the addition of tobacco seed oil methyl ester.