Petri net methodology for optimisation of heat integration and batch process scheduling

In this work, a Petri net (PN) based methodology for incorporating heat integration in batch process scheduling was presented. Heat integration and batch process scheduling can be optimized synchronously by this method. Scheduling model in this paper, firstly, was modified and constructed by PN. The disadvantages of timed Petri net (TPN), such as the asyntactic expression and unenforceable concurrent, were overcome availably and scheduling optimization can be achieved easily. Secondly, based on the similarity of PN and time-dependent heat cascade analysis technique (TDHCA) in carrying out discrete problem, PN for TDHCA was modeled. Using this model, the step to make sure streams distribution in temperature intervals was avoided and the calculation of heat deficiency was simplified. Finally, with the facility of multi-view integrated modeling, PN for scheduling and heat integration problems were fused together. The problems for incorporating scheduling in batch process heat integration were synchronously optimized by the combined model. An illustrative example was presented to demonstrate the validity and advantages of the proposed approach.