Scheduling for poly vinyl chloride process operation

Abstract

Scheduling problems which contains batch and continuous operations are known as the most difficult industrial scheduling problems. The short-term scheduling problem for manufacturing different grade polymers is addressed in this research. Since the stripping column and the dryers in the polymerization process are operated in a continuous mode and the reactors in a batch mode, the scheduling is a mixed problem of both continuous and batch operation units. The polymerization process is a sequential multipurpose process. In this paper a concept of the mathematical model proposed by Moon and Hrymak (Ind.Eng.Chem.Res., 1999) is used and extended to scheduling the production sequence in each unit. The proposed scheduling model has been applied to a large scale poly vinyl chloride process to verify its efficiency. The monthly scheduling results show the productivity increase by 8~15% compared with the operating data.