Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 11/15/2009
Publication Date: 11/15/2009
Citation: Knothe, G.H. 2009. Five Approaches to Improving the Fuel Properties of Biodiesel Including "Designer" Biodiesel [abstract]. 2nd International Congress on Biodiesel, Munich, Germany.
Technical Abstract: Biodiesel is usually produced from vegetable oils or animal fats or used cooking oils by a transesterification reaction with an alcohol, usually methanol, to give the corresponding mono-alkyl esters with glycerol as co-product. With a few exceptions, most common biodiesel feedstocks possess fatty acid profiles consisting mainly of five C16 and C18 fatty acids, namely, palmitic, stearic, oleic, linoleic and linolenic acids. Although biodiesel has many advantages compared to petrodiesel, this similarity in composition causes most biodiesel fuels to face the same major technical problems, such as poor cold flow and/or oxidative stability. Five approaches are possible to improve biodiesel fuel properties which are the use of additives and, under the general aspect of modifying the fatty ester composition, use of alcohols other than methanol to produce biodiesel, physical procedures such as fractionation, alternative feedstocks and feedstocks with genetically modified fatty acid profile. The latter two possibilities include microbiological approaches to biodiesel production and are also approaches to what can be termed "designer" biodiesel. Optimized fatty ester compositions of biodiesel include medium-chain saturated or monounsaturated fatty acids. Some recent examples will be given for biodiesel with such alternative composition together with the effect on fuel properties, especially improvement of cold flow.