Effect of modification of biodiesel by HZSM-5 zeolite on cold filter plug point

The main components of biodiesel including methyl oleate, methyl palmitate, methyl stearate, methyl linoleate and methyl laurate were modified at 250℃~350℃ using HZSM-5 zeolite catalyst to decrease the cold filter plug points(CFPP) of biodiesel. The influences of temperature and vacuum on the cold filter plug points(CFPP), coke deposits and iodine value were studied. The results show that at 300℃~350℃ an significant decrease of cold filter plug points is made, and the amount of coke deposits is less than 5%; meanwhile, the iodine value of methyl oleate is reduced. However, the iodine values of modified saturated fatty acid esters are increased. For the modification of methyl linoleate, the cold filter plug points of modified product do not decrease unless it is reacted at 350℃, and the amount of coke deposits is more than 10%.  As the biodiesel from the transesterification of animal fats with methanol（AFE）is modified, the cold filter plug point(CFPP) can be decreased by 19℃ at 325℃ and 0.01MPa. Meanwhile, the acid value of the biodiesel is less than 0.6mg/g, the iodine value(I.V) is 44.32g/100g, the kinematic viscosity(μ_t) is 4.397mm²/s, and the amount of coke deposits is less than 5% .