Poly(chloroethene) (PVC, polyvinyl chloride) is made from the monomer
chloroethene, commonly called vinyl chloride monomer or VCM. Most plants
use three high-yield steps, and the overall equation indicates a very
good atom economy (87.4%), with the main
co-product being water.
Improvements
Although manufacture of the monomer is a well-established process, constant
improvements are being made that reflect the need to implement green
principles.
| Selective catalysts |
New catalysts are able to reduce
the amount of by-products, increasing output |
| Use of oxygen |
Although using air as
a source of oxygen may seem the simplest option, using pure oxygen
from separated air drastically reduces the volume of emission gases |
| Processing of by-products |
Chlorine is recovered from by-products
either in a form that can be re-used in chlorination, or as hydrochloric
acid |
| Recycling process water |
Rather than cleaning process water
and discharging it, recycling on-site results in reduced water demand |
| Energy re-use |
Waste heat from exothermic processes
is transferred to where heat is needed on site |
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