Polyvinyl chloride (PVC) is produced by polymerization of vinyl chloride monomer (VCM). Unreacted VCM is pumped out of the reactor and condensed, and non-condensable gases are vented from the condenser. Depending on the temperature and pressure of the condenser, the vent stream also contains from 50 to 2,000 lb/h of VCM. As VCM emissions are tightly regulated, the vent stream must typically be incinerated and scrubbed before release.
The vent stream from the existing VCM condenser is sent to the VaporSep
system. VCM passes through the membrane at a greater rate than inert
gases, producing a VCM-enriched permeate and a VCM-depleted residue.
The permeate is recycled to the inlet of the existing compressor and
the residue is incinerated. The VCM recovered by the VaporSep system
is condensed in the existing condenser.
VaporSep systems allow PVC producers to recover 90% to 99+% of the VCM currently lost in vent streams, providing a significant economic benefit.
VaporSep systems are currently used by major PVC producers including Oxyvinyls, Westlake, Solvay, and Aiscondel.