ARS | Publication request: Effects of temperature cycling on formation of solid deposits in biodiesel

Submitted to: Annual Meeting and Expo of the American Oil Chemists' Society
Publication Type: Abstract Only
Publication Acceptance Date: November 28, 2011
Publication Date: April 29, 2012
Citation: Dunn, R.O. 2012. Effects of temperature cycling on formation of solid deposits in biodiesel. Annual Meeting and Expo of the American Oil Chemists' Society. p. IOP 1.

Technical Abstract: Biodiesel is produced mainly from transesterification of newly refined vegetable oils or used cooking oils with methanol. Most conversion processes require extensive treatment of product streams to remove co-product glycerol, unreacted alcohol, catalysts, and minor constituents. Minor constituents including saturated monoacylglycerols (MAG) and free steryl glucosides (StG) can interfere with biodiesel stability during storage. MAG and StG have very high melting points and, when present in small (trace) concentrations, can present problems when the fuel is stored in outside storage tanks during cold weather. If exposed to cold temperatures over a long period of time during storage, minor constituents can precipitate to form solid residues that are resistant to re-malting and dissolving back into solution. Furthermore, fuels stored in outside tanks may experience several warming/cooling cycles as temperatures rise in daytime and decrease at night. This study is designed to determine the effects of repeated temperature cycling between 25 °C (room temperature) and 5 °C (refrigerator temperature) on the rate of solid residue formation in methyl soyate (SME). Results showed temperature cycling accelerated the rate of solid formation compared to constant cooling of the SME at low temperatures over the same total time period.