Vinyl Chloride

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7 Vinyl Chloride Monomer Process

7.1 Basis of Design 7.1.1 Problem Statement

Vinyl chloride monomer (VCM) is one of the leading chemicals used mainly for manufacturing polyvinyl chloride (PVC). The PVC worldwide production capacity in 2005 was of about 35 million tons per year, with an annual growth of about 3%, placed after polyolefines but before styrene polymers. In the 1990s the largest plant in the USA had a capacity of about 635 ktons [1], but today there are several plants over one million tons. At this scale even incremental improvements in technology have a significant economic impact. Computer simulation, process optimization and advanced computer-control techniques play a determinant role. In the past the manufacture of VCM raised concerns regarding hazard, safety and pollution. Therefore, the VCM technology was among the first to profit from improvements suggested by process simulation. As result, the modern VCM plants are today among the cleanest and safest in the chemical process industries. In this project the raw materials are ethylene and chlorine of high purity. The design refers to a capacity of 300 kton/year VCM polymerization grade. Information about technology used in this project can be found in encyclopaedic works [1–3], review papers [4–6], patents, as well as on the websites of leading producers. Table 7.1 shows quality specifications, namely regarding key impurities [2]. The goal of this case study is to illustrate some generic issues raised by the conceptual design of a large-scale process involving several reaction and separation sections interconnected in a complex plant with recycles. The study emphasizes the intricate effects of handling the removal of numerous impurities generated in different reactors by a common separation system, with implications on process dynamics and plantwide control.

Chemical Process Design: Computer-Aided Case Studies. Alexandre C. Dimian and Costin Sorin Bildea Copyright © 2008 WILEY-VCH Verlag...