Effect of biodiesel fuels on diesel engine emissions

Biodiesel is a renewable transportation fuel consisting of fatty acid methyl esters (FAME), generally produced by transesterification of vegetable oils and animal fats. In this review, the fatty acid (FA) profiles of 12 common biodiesel feedstocks were summarized. Considerable compositional variability exists across the range of feedstocks. For example, coconut, palm and tallow contain high amounts of saturated FA; while corn, rapeseed, safflower, soy, and sunflower are dominated by unsaturated FA. Much less information is available regarding the FA profiles of algal lipids that could serve as biodiesel feedstocks. However, some algal species contain considerably higher levels of poly-unsaturated FA than is typically found in vegetable oils. Differences in chemical and physical properties among biodiesel fuels can be explained largely by the fuels’ FA profiles. Two features that are especially influential are the size distribution and the degree of unsaturation within the FA structures. For the 12 biodiesel types reviewed here, it was shown that several fuel properties – including viscosity, specific gravity, cetane number, iodine value, and low temperature performance metrics – are highly correlated with the average unsaturation of the FAME profiles. Due to opposing effects of certain FAME structural features, it is not possible to define a single composition that is optimum with respect to all important fuel properties. However, to ensure satisfactory in-use performance with respect to low temperature operability and oxidative stability, biodiesel should contain relatively low concentrations of both long-chain saturated FAME and poly-unsaturated FAME.

Review of biodiesel composition, properties, and specifications

As the fossil fuels are depleting day by day, there is a need to find out an alternative fuel to fulfill the energy demand of the world. Biodiesel is one of the best available resources that have come to the forefront recently. In this paper, a detailed review has been conducted to highlight different related aspects to biodiesel industry. These aspects include, biodiesel feedstocks, extraction and production methods, properties and qualities of biodiesel, problems and potential solutions of using vegetable oil, advantages and disadvantages of biodiesel, the economical viability and finally the future of biodiesel. The literature reviewed was selective and critical. Highly rated journals in scientific indexes were the preferred choice, although other non-indexed publications, such as Scientific Research and Essays or some internal reports from highly reputed organizations such as International Energy Agency (IEA), Energy Information Administration (EIA) and British Petroleum (BP) have also been cited. Based on the overview presented, it is clear that the search for beneficial biodiesel sources should focus on feedstocks that do not compete with food crops, do not lead to land-clearing and provide greenhouse-gas reductions. These feedstocks include non-edible oils such as Jatropha curcas and Calophyllum inophyllum , and more recently microalgae and genetically engineered plants such as poplar and switchgrass have emerged to be very promising feedstocks for biodiesel production. It has been found that feedstock alone represents more than 75% of the overall biodiesel production cost. Therefore, selecting the best feedstock is vital to ensure low production cost. It has also been found that the continuity in transesterification process is another choice to minimize the production cost. Biodiesel is currently not economically feasible, and more research and technological development are needed. Thus supporting policies are important to promote biodiesel research and make their prices competitive with other conventional sources of energy. Currently, biodiesel can be more effective if used as a complement to other energy sources.

A comprehensive review on biodiesel as an alternative energy resource and its characteristics

As a renewable, sustainable and alternative fuel for compression ignition engines, biodiesel instead of diesel has been increasingly fueled to study its effects on engine performances and emissions in the recent 10 years. But these studies have been rarely reviewed to favor understanding and popularization for biodiesel so far. In this work, reports about biodiesel engine performances and emissions, published by highly rated journals in scientific indexes, were cited preferentially since 2000 year. From these reports, the effect of biodiesel on engine power, economy, durability and emissions including regulated and non-regulated emissions, and the corresponding effect factors are surveyed and analyzed in detail. The use of biodiesel leads to the substantial reduction in PM, HC and CO emissions accompanying with the imperceptible power loss, the increase in fuel consumption and the increase in NOx emission on conventional diesel engines with no or fewer modification. And it favors to reduce carbon deposit and wear of the key engine parts. Therefore, the blends of biodiesel with small content in place of petroleum diesel can help in controlling air pollution and easing the pressure on scarce resources without significantly sacrificing engine power and economy. However, many further researches about optimization and modification on engine, low temperature performances of engine, new instrumentation and methodology for measurements, etc., should be performed when petroleum diesel is substituted completely by biodiesel.

http://www.abe-research.illinois.edu/pubs/T_Grift/EffectOfBiodieselOnEnginePerformancesAndEmissions.pdf

Effect of biodiesel on engine performances and emissions

Political, economic and environmental impacts of biofuels: A review

Effect of ethanol blending with biodiesel on engine performance and exhaust emissions in a CI engine

Fuel production from waste vehicle tires by catalytic pyrolysis and its application in a diesel engine

Optimization of fuel production from waste vehicle tires by pyrolysis and resembling to diesel fuel by various desulfurization methods

Biodiesel from safflower oil and its application in a diesel engine

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 emissi...

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Papers

Effect of ethanol blending with biodiesel on engine performance and exhaust emissions in a CI engine

Fuel production from waste vehicle tires by catalytic pyrolysis and its application in a diesel engine

Optimization of fuel production from waste vehicle tires by pyrolysis and resembling to diesel fuel by various desulfurization methods

Biodiesel from safflower oil and its application in a diesel engine

Effect of Cotton Seed Oil Methyl Ester on the Performance and Exhaust Emission of a Diesel Engine