PRODUCTION OF PVC
By thermally cracking naphtha or natural gas, the basic petrochemical industry manufactures ethylene and propylene. Naphtha is mainly supplied from the petroleum refinery industry, which uses crude oil as raw material. The chloro-alkali industry produces caustic soda, chlorine and hydrogen through electrolysis using industrial grade salt as main raw material.
At a first stage in the PVC production process ethylene and chlorine are combined to produce an intermediate product called ethylene dichloride; this is then transformed into vinyl chloride, the basic building block of polyvinyl chloride or PVC. The process of polymerization links together the vinyl chloride molecules to form chains of PVC:
At a first stage in the PVC production process ethylene and chlorine are combined to produce an intermediate product called ethylene dichloride; this is then transformed into vinyl chloride, the basic building block of polyvinyl chloride or PVC. The process of polymerization links together the vinyl chloride molecules to form chains of PVC:
The PVC produced in this way is in the form of a white powder. This is not used alone, but blended with other ingredients to give formulations for a wide range of products such as PVC piping.