Improving the low temperature flow properties of palm oil biodiesel: Addition of cold flow improver

Palm methyl ester (PME) was prepared using an alkali-catalyzed transesterification reaction, and its cold flow properties (CFP) were studied. Commercial DEP (trade name) and polyglycerol ester (PGE), and self-made PA (given name by our laboratory researchers), were used as cold flow improvers (CFIs) to improve the CFP of the biodiesel, and the effects of these CFIs on the CFP of PME were investigated. The results showed that the peak crystallization temperature of PME was very close to the cold filter plug point (CFPP). There was no unique linear relationship between the CFPP and the content of saturated fatty acid methyl esters. When used individually as CFIs, DEP, PGE and PA exerted only moderate pour point depression effects on the biodiesel, and effects to decrease the CFPP of PME were only observed when the CFI concentration was 1% or higher. Compared with single-compound CFIs and CFIs formulated from two components, at a specified complex formulation ratio, CFIs formulated from three components exhibited the best performance. When the ratio of DEP:PGE:PA was 3:1:1 or 2:2:1, the CFPP of PME was decreased by 7 °C.