edc/vcm technology

Ethylene-based VCM manufacturing begins by combining ethylene and chlorine to make ethylene dichloride (EDC). EDC is produced by combining ethylene and chlorine using either direct chlorination, which uses pure chlorine and ethylene, or oxychlorination, in which ethylene reacts with chlorine in hydrogen chloride.

Vinyl chloride monomer (VCM) is made by cracking EDC (ethylene dichloride, 1,2-dichloroethane) to yield equimolar amounts of VCM and hydrogen chloride (HCl).

C₂H₄Cl₂ C₂H₃Cl + HCl

EDC is made by a direct chlorination process, in which chlorine is added to ethylene.

Half of the chlorine consumed by this reaction ends up as HCl when the EDC is cracked to VCM. This HCl is recovered in the subsequent VCM purification step, and reacted with oxygen and additional ethylene in the oxychlorination process to make more EDC.

C₂H₄ + 2HCl + ½O₂ C₂H₄Cl₂ + H₂O

Combining these three reaction steps into an integrated operation forms the basis for the balanced VCM process, in which vinyl chloride is made from chlorine, ethylene, and oxygen.

Other components of the VCM process include VCM Purification, EDC Purification, Hydrogenation, and byproduct separation and catalytic oxidation.

Balanced VCM Process