Simultaneous Synthesis of WHEN Based on Superstructure Modelling Considering Thermodynamic and Economic Factors

Abstract

Abstract To explicitly reveal the interaction mechanism between work and heat integration considering both thermodynamic and economic analysis, an improved superstructure, coupling of work exchange networks (WEN) and heat exchange networks (HEN), is proposed for simultaneous synthesis of work and heat exchange networks (WHEN) in this paper. The formulations based on exergy analysis are developed to determine the cold or hot identity of process streams. Afterwards, economic analysis is performed by formulating a cost-based mixed-integer nonlinear programming (MINLP) model to optimize the sequence of work and heat integration, aiming to minimize the total annual cost (TAC). Finally, an example study selected from the open literature is conducted to demonstrate the efficacy of the proposed methodology, where the solutions show a diminution of 40.4% in TAC of HEN prior to WEN, compared with that of WEN prior to HEN.