PVC is a kind of thermoplastic synthetic resin developed early in China. Currently, according to different sources of raw materials and routes of production processes, domestic PVCs can be roughly divided into two sorts – calcium carbide process-based PVC and ethylene process-based PVC. The ethylene process route covers the production of 1,2-dichloroethane (EDC) through ethylene oxychlorination with petroleum ethylene as its raw material, the polymerization of PVC through ethylene dichloride (EDC) pyrolysis to vinyl chloride monomer (VCM), and PVC production through import of a small amount of 1,2-dichloroethane and VCM.