Simultaneous Optimization of Short-Term Scheduling and Heat Integration Schemes for Multipurpose Batch Plants

A new synthesis methodology is developed to optimize process scheduling and direct heat integration schemes for multipurpose batch plants simultaneously. Firstly, the concept of associated task is introduced to describe the heat transfer requirements of production tasks and an improved State-Tasks-Network representation is adopted to capture all streams-streams, units-streams and units-units heat integration opportunities. Besides, the detailed design of heat transfer schemes and time sharing mechanism of heat exchangers are also involved in the proposed framework by considering heat transfer tasks-units allocation constraints. Then, a mixed integer linear programming (MILP) model is formulated to maximize profit. It should be noted that the trade-off between utility consumption and equipment cost has been taken into account. At last, an illustrative example is presented to demonstrate the validity and advantages of the proposed approach.