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United States Department of Agriculture

Agricultural Research Service

Title: Precombustion of Fatty Acids and Esters, the Components of Transesterified Vegetable Oils Used As Alternative Diesel Fuel

item Knothe, Gerhard
item Bagby, Marvin - RETIRED, USDA/ARS

Submitted to: American Institute of Chemical Engineers
Publication Type: Abstract Only
Publication Acceptance Date: November 21, 1997
Publication Date: N/A

Technical Abstract: Every diesel fuel, conventional or alternative, upon injection into the combustion chamber passes through a precombustion phase prior to ignition. During this precombustion phase, the fuel is subjected to a temperature and pressure gradient. Chemical reactions occur during precombustion. Species that influence the subsequent combustion process arise as a result of these reactions. In order to achieve proper combustion and reduced exhaust emissions, it is necessary to influence the precombustion process and the species arising there. The precombustion behavior of several fatty compounds that are present in vegetable oil-based alternative diesel fuel ("biodiesel") was investigated. Stearic, oleic, linoleic, and linolenic acids, as well as corresponding methyl, ethyl, propyl, and butyl esters, were subjected to precombustion conditions. Various hydrocarbons, including straight chain and branched alkanes, alkenes, cycloalkanes, and aromatic species with different side chains were identified by gas chromatography mass spectrometry as precombustion products. Oxygenated species including saturated and unsaturated aldehydes, ketones and shorter chain esters were also observed.

Last Modified: 5/5/2015
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