Stream vinyl acetate monomer process

The final example to illustrate our plantwide control design procedure comes from Luyben and Tyreus (1998), who present design details of an industrial process for the vapor-phase manufacture of vinyl acetate monomer. This process is uniquely suited for researchers pursuing process simulation, design, and control studies. It has common real chemical components in a realistically large process flowsheet with standard chemical unit operations, gas and liquid recycle streams, and energy integration. 

The process considered in this chapter involved the production of vinyl acetate monomer. It features many unit operations, many components, nonideal phase equilibrium, unusual reaction kinetics, two recycle streams, and three fresh reactant makeup streams. 

After the polymerization reactors, the unreacted monomer must be removed from the polymer stream. In your company s existing polymerization units, the monomer is removed in a distillation/stripping column. Methanol vapor is fed to the bottom of the column and a mixture of methanol and vinyl acetate monomer is taken as an overhead product. The PVAC exits from the bottom of the column in a methanol solution. To minimize product color formation, column temperatures should not exceed 240°F. The bottoms from the PVAC/methanol column must have a solids content of 36 to 40% to be suitable for existing processing equipment downstream. 

The method used in Procedure 2-2, in a sense, is an adaptation of an old patented process for the commercial preparation of poly(vinyl acetate). In that procedure, as a stream of monomer is added to a polymerizing reaction mixture, an equal volume of the partially polymerized mixture is withdrawn to a finishing vessel where the reaction is allowed to go to completion at reflux [81]. 

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