An Extended Superstructure-Based Model for Synthesis of Compression-Heat-Integrated Heat Exchanger Networks Coupled with Multiple Utilities

Energy-integration methods for process systems such as Heat Exchanger Network Synthesis (HENS) and Work-Heat Exchanger Network Synthesis (WHENS) have been developed to promote energy conservation and reduce emissions in process systems. The proper integration of compression heat and HENS with multiple utilities instead of a single-level utility facilitates improving energy utilization. This paper introduces an extended superstructure-based model for the synthesis of a compression-heat-integrated heat exchanger network coupled with multiple utilities. The superstructure optimizes both heat exchange matches and the usage of high-, medium-, and low-pressure steam levels generated by the utility system. Compression heat for certain streams is also optimized to explore the interaction of compression work and utility consumption. A mixed-integer nonlinear programming model is established to simultaneously minimize the total annualized cost and exergy consumption. To demonstrate the feasibility of the proposed model, an example with two cases is investigated, indicating that compression heat can significantly improve heat recovery and energy efficiency.