Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 7/1/2008
Publication Date: 7/18/2008
Citation: Dunn, R.O., Knothe, G.H., Moser, B.R., Erhan, S.Z. 2008. Biodiesel [abstract]. MWA Bioenergy Research Forum, Peoria, IL.
Technical Abstract: Biofuels are continuously gaining importance in light of the dependence on diminishing and imported petroleum, coupled with rising energy prices, environmental issues and the need to strengthen the domestic agricultural economy. Biodiesel, which is obtained from vegetable oils, animal fats or used frying oils by means of a chemical reaction called transesterification, is such a fuel. It is suitable for use in diesel (compression-ignition) engines which power buses, trucks, ships, construction equipment, railroad locomotives and even passenger vehicles. An estimated 450 million gallons of biodiesel were produced commercially in 2007 in the United States. The transesterification reaction reduces the thickness (viscosity) of the oil or fat, making it more suitable for use in an engine. Otherwise, the thickness of the oil or fat would lead to undesirable effects such as engine deposits. Biodiesel is technically competitive with diesel fuel derived from petroleum. Technical advantages of biodiesel include biodegradability, safer handling, positive energy balance, negative carbon dioxide balance, inherent lubricity, and reduction of most exhaust emissions. The issue of lubricity has made biodiesel attractive for use with modern ultra-low-sulfur diesel fuels whose poor lubricity can wear out fuel injectors. Biodiesel, however, also faces technical problems which impair the use of biodiesel under certain conditions. These problems include behavior at low temperatures due to formation of solids at around 32 deg F (0 deg C), storage stability when exposed to air, and one kind of exhaust emissions known as nitrogen oxides (NOx). Solving these problems is rendered difficult because the solution to one problem tends to aggravate one or more of the other problems. Besides better understanding of the causes of these problems, ARS researchers use several approaches to solving these problems. These approaches include the use of additives, new fuel formulations and altering the nature of the major components that comprise biodiesel.