A new decomposition approach for synthesis of heat exchanger network with detailed heat exchanger sizing

Due to the complexities arisen from the non-convexities in the mathematical models for the HEN synthesis incorporating detailed exchanger design, constant heat transfer coefficients and short-cut model for the calculation of exchanger capital cost are used for a majority of approaches to obtain a synthetic network topology, which causes inaccurate heat transfer areas and trade-offs between energy usage and capital investment. This paper presents an enhanced iterative-based decomposition algorithm to achieve realistic HEN synthesis with detailed heat exchanger sizing, which targets to overcome the drawbacks associated with the use of short-cut heat exchanger model in configuration synthesis, and further presents how these exchanger details can be employed to lead the HEN synthesis towards generating more cost effective solutions. Fouled individual stream heat transfer coefficients and corrected total process cost are updated iteratively between heat exchanger design (HED) and HEN superstructure (HENS) to guide HEN topology optimization. Global optimization for heat exchanger sizing is achieved in each iteration using a global solver BARON/GAMS.34 to overcome instability in the iteration process caused by local optimum issues. A case study shows that it can provide a better solution than the results in the literature with a lower total annual cost and computational time.