Reducing the crystallization temperature of biodiesel by winterizing methyl soyate

Methyl soyate, made from typical soybean varieties, has a crystallization onset temperature (T-CO) of 3.7 degrees C and, as a biodiesel fuel, is prone to crystallization of its high-melting saturated methyl esters at cold operating temperatures. Removal of saturated esters by winterization was assessed as a means of reducing the T-CO of methyl soyate. Winterizing neat methyl esters of typical soybean oil produced a T-CO of -7.1 degrees C, but this was not an efficient way of removing saturated methyl esters because of the low yield (26%) of the separated liquid fraction. However, a T-CO of -6.5 degrees C with 86% yield was obtained by winterizing the neat methyl esters of a low-palmitate soybean oil; a T-CO of -5.8 degrees C with 77% yield was obtained by winterizing methyl esters of normal soybean oil diluted with hexane.