A novel approach for scheduling of batch plants with variable batchsizes

The timed Petri nets-based approach has been shown to be a very promising way to tackle the complicated operation scheduling in multipurpose/multiproduct batch plants. In this paper, it is extended to deal with the scheduling problems of batch plants with variable batchsizes. In the formulation, the variable batchsizes in unit operations are implicitly represented as time places attached with a time interval. Also, the optimal scheduling algorithms for this class of batch plants are developed. From the algorithms, the appropriate job sequence and batch sizes to maximize the profit can be solved. The effectiveness of the proposed approach and algorithms are illustrated through two case studies.