Generalized Model for Work and Heat Exchange Network Synthesis Considering Pressure Drop Effects

Abstract

This work proposes a detailed superstructure to synthesize work and heat exchange networks (WHENs). The main objective of this generalized model is to evaluate the effect of pressure drops on heat exchanger design and the corresponding impact on process economics. The pressure drop modeling is performed by considering that the process streams can pass through the shell or tube side of the heat exchangers according to the energy requirements of the networks. The proposed superstructure defines the heat and work units at each stage of the network, the energy identity of the streams (low-pressure hot/high-pressure cold), the pressure drop in each heat exchanger, heater, and cooler, and the side on which the streams pass through the heat exchangers. The proposed WHEN synthesis methodology is tested on three case studies: (a) two small academic problems and (b) a natural gas liquefaction (LNG) process. For the LNG process, the results show a 6.11% reduction in TAC based on a 66.49% lower capital cost compared to previous work.