Submitted to: Annual Meeting and Expo of the American Oil Chemists' Society
Publication Type: Abstract Only
Publication Acceptance Date: 2/21/2007
Publication Date: 5/13/2007
Citation: Dunn, R.O. 2007. Effect of Saturated Mono- and Diacylglycerols on Cold Flow Properties of Biodiesel [abstract]. Annual Meeting and Expo of the American Oil Chemists' Society. p. 92. Interpretive Summary:
Technical Abstract: Biodiesel in the form of fatty acid methyl esters (FAME) derived from vegetable oils and animal fats is very attractive as a renewable and domestically available alternative fuel for combustion in direct-injection compression-ignition (diesel) engines. Past research on the cold flow properties of soybean oil-FAME has focused on mitigating effects of high-melting point saturated long-chain FAME components. However, experience in the field has shown that other problems may arise when biodiesel is stored in outdoor tanks during cold weather. In many instances problems such as gel dispersions on the bottom of storage tanks and clogged fuel filters occurred in the field. These problems were attributed to the presence of contaminants such as saturated mono- and diacylglycerols even when the biodiesel fuel as delivered was within ASTM D 6751 specifications for 'total glycerin' (0.24 wt% maximum). This work examines effects of adding small concentrations of saturated long-chain mono- and diacylglycerols on cold flow properties of soybean oil-FAME. Cloud point, freezing point, wax appearance point, cold filter plugging point (CFPP) and kinematic viscosity were analyzed. Heating and cooling differential scanning calorimetry (DSC) scans were performed on mixtures of monostearin and methyl oleate. Results showed that saturated long-chain mono- and diacylglycerols were not very soluble in soybean oil-FAME. Nevertheless, these contaminants have a profound impact on cold flow properties of biodiesel.