Sequential Methodology for Simultaneous Batch Process Scheduling and Water Reuse Optimization

This paper presents a new sequential methodology for incorporating water reuse optimization in batch process scheduling. First, the schedule is optimized to meet the economic objective such as makespan or profit. Next, alternate schedules are generated through a stochastic search-based integer cut procedure that adds further constraints to the scheduling formulation. Finally, source-sink allocation technique is applied to each of the resulting schedules to establish the minimum water costs. The method differs from other sequential approaches published in literature in that the water optimization problem is solved with the intent to retain the optimality of the scheduling solution.