Enhancing the cold flow properties of waste cooking methyl ester

The chemical compositions of waste cooking methyl ester (WCME) and -10# petroleum diesel (-10PD) were analyzed by Gas Chromatograph-Mass Spectrometer. The cold flow properties of WCME were studied by the cold filter plugging point tester and the kinematic viscosity tester. Through blending and adding cold flow improver, the cold flow properties of WCME were improved. The study shows that WCME is mainly composed of saturated fatty acid methyl esters (SFAME) and unsaturated fatty acid methyl esters (UFAME). The mass fraction of SFAME and UFAME are 27.63% and 71.81%, respectively. The cold filter plugging point (CFPP) of WCME is 0℃, and the viscosity of WCME is 4.41mm2/s at 40℃. Through blending, the CFPP of blending oils has decreased with the lowest being -13℃ at B20. With the decrease of the volume ratio of WCME, the kinematic viscosity of blending oils is lower than the WCME and near the -10PD. By adding of cold flow improver, the CFPP of WCME, B10 and B20 decreased from 0℃, -8℃, and -13℃ to -4℃, -26℃ and -25℃.