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ARS Home » Research » Publications at this Location » Publication #193238


item Hess, Melissa
item Haas, Michael
item Foglia, Thomas

Submitted to: American Chemical Society National Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 3/15/2006
Publication Date: 3/26/2006
Citation: Hess, M.A., Haas, M.J., Foglia, T.A. 2006. Reformulating biodiesel to reduce nox emissions. American Chemical Society National Meeting. Paper No. TECH-49.

Interpretive Summary:

Technical Abstract: The use of biodiesel, a diesel engine fuel produced from agriculturally derived fats and oils, offers many advantages over petrodiesel, but has been shown in certain instances to increase emissions of oxides of nitrogen (NOx), a federally regulated pollutant. The work described here involved modification of the fatty acids of a soy oil-based biodiesel and an investigation of the effects of these changes on NOx emissions of the fuels. Two different fuel modifications were conducted. The first involved isomerizing the fatty acid double bonds in the soy oil biodiesel from the cis- to the trans-configuration, which results in a more linear structure similar to saturated fatty acids. The second involved transesterifying soy polyols, which have hydroxyl groups added to the former double bonds of the fatty acid chains of soy fatty acids, thus reducing the iodine value of the fuel as well as altering the structure of the fatty acyl chain. The NOx-forming tendencies of the modified biodiesels were measured during operation of a naturally-aspirated, single cylinder diesel engine. It was found that fuel containing trans- unsaturated fatty acid esters produced elevated NOx emissions relative to its all-cis- analog, whereas NOx output was reduced, relative to commercial soy biodiesel, upon combustion of the polyol fuel.