Synthesis of Multi-period Heat Exchanger Network Considering Characteristics of Sub-periods

To reduce computational loads for synthesis of multi-period Heat Exchanger Network (HEN), two methods, including a representative period method and a stepwise simplifying method, are proposed by considering the sub-period characteristics. In the representative period method, a representative period is selected, and the optimal HEN structure in this sub-period is obtained by solving a single-period HEN synthesis model. Then, the heat transfer areas and operational parameters are optimized in the fixed optimal structure. On the other hand, the stepwise simplifying method finalizes the multi-period HEN by applying the strategies of single-period HEN optimization, structure merging and multi-stream heat exchanger substitution. Results of the case studies indicate that the representative period method is suitable to solve the problems that feature large number of sub-periods and durations with different length, whereas the stepwise simplifying method can readily reach cost-effective HEN structures that satisfy the multi-period operations without being affected by variations of sub-period durations. Both of these two methods can rapidly facilitate solutions to multi-period HEN synthesis problems at large scale.