ABSTRACT

Batch processes differ from continuous processes in several ways. The main difference is that time is inherent in batch processes. In batch processes, every task has a definite duration with starting and finishing times, whereas in continuous processes, time is important during non-steady-state operation. As a result, scheduling of batch processes is vital to the operation of any batch facility. Furthermore, in batch plants, detailed requirements for the various products may be specified on a day-to-day basis. A production schedule must indicate the sequence and manner in which the products are to be produced and specify the times at which the process operations are to be carried out. It is clear that the overall productivity and economic effectiveness of batch plants depend critically on the production schedule as it harmonizes the entire plant operation to attain production goals. While flexibility of batch plants improves productivity, it also makes plant scheduling a challenging task. Much research has focused on developing optimization techniques for scheduling batch plants with the aim of reducing the CPU time required to attain the optimal objective value.