General reordering algorithm for scheduling of batch processes.

A sequencing algorithm applicable to various scheduling problems is proposed. It consists of two reordering operations, the insertion of a job and the exchange of two jobs. We propose a new reordering algorithm which can be used to solve scheduling problems of multiproduct processes with network structure.The proposed reordering algorithm is applied to the scheduling problem of a multiproduct batch process consisting of parallel production lines with a shared unit. It is shown that the simultaneous reordering of several jobs effectively avoids becoming trapped in a bad local optimum. To execute simultaneous reordering of jobs, an algorithm consisting of two steps, the aggregation of jobs and the reordering of aggregated jobs, is proposed.