Timed Petri-net representation for short term scheduling of multiproduct batch plants

Scheduling is one of the interesting research fields in batch chemical industries, which substantially differs from that in discrete manufacturing systems. One of the main differences between these two fields is the intermediate storage of materials, which appears in chemical processes. This situation prevents the direct applicability of some of the scheduling techniques (such as Petri nets) used for discrete manufacturing systems, in batch chemical plants. In this paper, a timed Petri nets-based formulation for scheduling of multiproduct batch chemical plants with unlimited intermediate storage policy is presented. To find the best schedule, a modified branch-and-bound and timed-place Petri net execution (MBBTE) solution algorithm is proposed, which will be examined through an illustrative example.