Enhanced deterministic approach for heat exchanger network synthesis

Stage-wise superstructure (SWS) is one of the most widely used methods for Heat Exchanger Network (HEN) synthesis. Approaches to obtain optimal HEN solution can be based on the deterministic algorithm, but it is difficult for solving a large-scale problem since the complexities arisen from nonlinearities of SWS. Several methods which employed stochastic algorithms and meta-heuristic approaches have been proposed to tackle the problem. However, it determines a near-optimal HEN configuration from a series of stochastic solutions which are obtained by the execution of many computational operations, thus it is time consuming and a global optimum will not be achieved from only randomly generated results. In this study, an enhanced SWS is presented, in which new constraints and variables are added to avoid conflicted calculation of non-isothermal mixing energy balance and reduce the redundant combinations. Moreover, the present model is extended to allow a flexible requirement of stream splitting for practical application. Then, a deterministic-based global solver (GAMS/BARON) is applied in solving three case studies, operated on computer: I7-8565U. The results showed that the proposed approach can provide a cost-efficient HEN solution with a lower TAC than that obtained from existing stochastic and deterministic algorithms.