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United States Department of Agriculture

Agricultural Research Service

Title: Analysis of Biodiesel Fuel and Monitoring Progress of the Transesterifica Tion Reaction by Fiber-Optic Near Infrared Spectroscopy

item Knothe, Gerhard

Submitted to: ASAE Annual International Meeting
Publication Type: Abstract Only
Publication Acceptance Date: July 22, 1999
Publication Date: N/A

Technical Abstract: Biodiesel is an alternative diesel fuel derived from vegetable oil and animal fats. It is obtained by reacting an oil or fat with an alcohol (transesterification) to give the corresponding mono-alkyl esters. Several analytical methods exist for analyzing the quality of biodiesel fuel obtained from a transesterification reaction and for monitoring the extent of the transesterification reaction. Gas chromatography (GC) is currently the preferred analytical method and is applied in biodiesel standards. On the other hand, concerns exist about the rapidity of GC in a production situation as well as the complexity of analysis and equipment maintenance. Near-infrared (NIR) spectroscopy using a fiber-optic probe is an alternative to the GC method. The NIR spectra of vegetable oils and their methyl esters show differences in certain NIR peak regions which can be used for quantitation. The NIR method is significantly faster and easier to use than GC and requires only minimal maintenance. The progress of the transesterification reaction can be monitored with excellent results and inductive statements on the quality of a biodiesel fuel are possible.

Last Modified: 4/20/2015
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