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United States Department of Agriculture

Agricultural Research Service

Title: Fat and Fuel Quality Indices Applied to Biodiesel

Author
item Knothe, Gerhard

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: October 27, 2000
Publication Date: N/A

Technical Abstract: Biodiesel is an alternative diesel fuel defined as the mono-alkyl esters of a vegetable oil or animal fat. Thus, many parameters used in fatty acid chemistry and in fuel chemistry have been applied to biodiesel. A notable parameter used in fatty acid chemistry that has been applied to biodiesel is the iodine value. However, the use of the iodine value suffers from several significant disadvantages, which are related to its unsatisfactory specificity in taking fatty acid structure and composition of mixtures into account. Some straightforward examples are used to underline this observation. Furthermore, results from oxidative stability studies are applied to the iodine value. It appears that a modified index can be developed which would take fatty acid structure and composition of mixtures into account. The development of such an index could have implications for the use of the iodine value in fatty acid chemistry in general. As a conventional diesel fuel-related parameter, the cetane number (an index related to fuel combustion) has been applied extensively to biodiesel. In this case also, more dated research has shown that an alternative index may be more suitable. Sometimes the so-called cetane index, a calculated value, has been used in conjunction with biodiesel instead of the cetane number. The cetane index is also not suitable for biodiesel. These examples show that care must be taken when applying parameters from apparently related fields to biodiesel.

Last Modified: 8/22/2014
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