大豆油生物柴油低温流动性能影响的研究

A bio-diesel fuel sample, methyl esters from soybean oil (SME), was prepared by basic catalysis and transesterification. The important characteristics such as acid value, free glycerol, viscosity (ν), total glycerol, ash and phosphor content were determined. The v and the low-temperature flowing properties (LTFP) such as solidification point (SP), pour point (PP) and cold filter plugging point (CFPP) were tested by standard petroleum methodologies. LTFP of SME is hardly influenced by methanol, water and glyceride that exist in SME when their contents are less than their specifications required. When SME is cooled, the saturated fatty acid methyl esters (FAME) in SME will co-crystallize first. Thus LTFP of SME is greatly influenced by the saturated FAME in SME. Then the approaches for improving LTFP of SME were explored. Five cold-flow additives, No.0 diesel fuel (DF0), No-20 diesel fuel (DF-20) and ethanol were tested. DF0 can improve ν of SME, but can not greatly affect LTFP of SME. DF-20 and ethanol can greatly improve CP, PP, CFPP and ν of SME. Three cold-flow additives can greatly reduce SP and PP of SME, but only one can improve CFPP a little. All five cold-flow additives can increase ν of SME.