ABSTRACT
ORIS is the abbreviated name for Organsko Remiska Industrija Skopje, which is a joint stock company in the Republic of Macedonia. The plant was placed into operation in 1964. ORIS manufactures basic chemicals which include caustic soda and chlorine, herbicides, detergents, various synthetic fibers, PYA, PVC. Vinyl chloride monomer (VCM ) is the precursor to PVC, one of the most widely used commodity plastics in the world. PVC resin is manufactured by a suspension process. The suspension polymerization is performed in reactors with conversion rates typically between 89 to 91 % of the monomer (VCM). The polymerization reaction is terminated by injecting an inhibitor, whereupon unconverted VCM is removed from the polymerization reactors by heating up the polymer slurry and applying vacuum technology to remove unreacted VCM vapors. The polymer slurry is removed from the reactors and sent to slurry tanks, and from there, the slurry resin product goes on to polymer drying and finishing stages to produce a final resin product. The PVC plant is comprised of four single agitator reactors (CSTRs). Residual or unconverted VCM is also removed from the polymer slurry prior to sending the resin to the finishing stages of the operation. This is traditionally accomplished by the use of a series of stripper columns.
