The Hybrid Scheduling System for the Store Block

In general, it is difficult to schedule operation for whole large chemical plant. In the case of polymerization plant, the plant operation is usually scheduled to divide to some blocks, which are production block, store block, and so on. The production block is scheduled to minimize production cost. On the other hand, the store block is scheduled to operate the production block using feasible scheduling. The following features make the store block scheduling difficult. (1) The product must be treated as a continuum. (2) The product is handled by two or more machines concurrently. (3) The capacities of queues for intermediates have upper bound. (4) The operations are not necessarily started when the operations can be started. (5) The store block is very large system. This paper proposed the hybrid scheduling system to achieve Just-In-Time (JIT). The proposed system determines the schedule of store block using push type algorithm by the production block demand, and determines that using pull type algorithm by the delivery demand. The effectiveness of the proposed system is assessed via numerical studies.