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Location: Bio-oils Research

Title: The potential contribution of biodiesel with improved properties to an alternative energy mix

item Knothe, Gerhard - Gary

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 8/19/2010
Publication Date: 8/19/2010
Citation: Knothe, G.H. 2010. The potential contribution of biodiesel with improved properties to an alternative energy mix [abstract]. 2nd International Symposium, Kyoto University, Global Centers of Excellence Program.

Interpretive Summary:

Technical Abstract: Continuing and increasing world-wide concerns regarding the availability of petroleum and other "conventional" sources of energy have sparked the search for sustainable sources of energy. Fuels derived from renewable biological sources (biomass) play a prominent role among the sustainable energy sources. Biodiesel, the mono- alkyl esters of vegetable oils or animal fats, is one of the significant biomass-derived fuels. Biodiesel is obtained from vegetable oils or other triacylglycerol feedstocks by transesterification with an alcohol, yielding glycerol as a co-product. While biodiesel is technically competitive with petroleum-derived diesel fuel (petrodiesel), problems that have beset biodiesel include poor cold flow (CF) and oxidative stability (OS). These problems are due, to a great extent, to most biodiesel fuels containing mainly the same five C16 and C18 fatty acid (FA) esters. Five methods, including FA profile modifications, exist for overcoming these problems. Properties of individual esters show that acids such as decanoic or palmitoleic acids have the potential to improve biodiesel properties when enriched in the feedstock. The alcohol can also play a role, with alcohols other than methanol, imparting more favorable properties to biodiesel. The aforementioned technical problems of biodiesel also afflict feedstocks, perhaps more severely, with claimed high production potential. For example, algae-based biodiesel fuels would likely possess even worse CF and OS than most vegetable oil-based biodiesel. Renewable diesel is also a fuel derived from vegetable oil feedstocks. It is obtained by hydrodeoxygenation and resembles petrodiesel in its composition. Biodiesel and renewable diesel are compared regarding their properties, including mass and energy balance as well as potential uses. Biodiesel has a favorable balance compared to other biomass-derived fuels, also when including co-products. Nevertheless, for fuels such as biodiesel and others to be more competitive, the fuel properties as well as the economics and production potential need to be improved.