Method for preparing vinyl chloride using dichloroethane as raw material

The invention discloses a method for preparing vinyl chloride using dichloroethane as raw material, comprising the following steps: feeding gaseous dichloroethane of 245-265 DEG C and 2.9-3.5 Mpa into a cracking furnace for cracking at 470-500 DEG C, then obtaining mixture of dichloroethane, vinyl chloride and hydrogen chloride, and feeding the mixture to the subsequent separation section to obtain vinyl chloride, wherein the detention time of the materials is 20-30 seconds in a cracking tube, the linear speed of the materials at the outlet of the cracking tube is 25-35 m/s, the diameter of the inlet is less than the diameter of the inlet, and the pressure difference of the materials at the inlet and outlet is 0.9-1.5 Mpa. The invention reduces the usage of fuel gas from 110 kg/t-vcm to 68 kg/t-vcm, increases the yield of vinyl chloride by about 15%, and prolongs the decoking period of the cracking furnace from 4-5 months to 8-10 months.