Optimal scheduling of multiproduct batch processes for various intermediate storage policies

In this paper, we suggest optimal scheduling strategies for serial multiproduct batch processes to minimize the makespan as an objective function. The strategies are formulated as mixed-integer nonlinear programming (MINLP) for various storage policies under consideration of nonzero transfer and setup times. The major storage policies for multiproduct multiunit batch processes considered in this paper are unlimited intermediate storage (UIS), no intermediate storage (NIS), finite intermediate storage (FIS), zero wait (ZW), and mixed intermediate storage (MIS). The algorithms to calculate the process completion times are developed for each policy. Two examples are tested to evaluate the robustness of this strategy and reasonable computational times.