Generalized Simultaneous Optimization Model for Synthesis of Heat and Work Exchange Networks.

Abstract

In this work, a new superstructure for simultaneous synthesis of work and heat exchange networks (WHEN) is presented. In the proposed model, an explicit modeling of the identity changes of the process streams is developed. The main idea behind this approach is to allow the pressure-change streams act as low-pressure hot streams as well as high-pressure cold streams in different stages of the WHEN without using any predefined manipulation routes. In this sense, using this novel approach, all possible thermodynamic paths of the process streams are considered into the synthesis problem. The novel formulation is done without incorporating new binary variables and nonlinear constraints in the problem. Therefore, the proposed superstructure allows to improve the obtained solution and to reduce the computational burden. These improvements are shown by using three case studies with different size and complexity. In most cases, savings of approximately 1%–7% in total annualized cost were observed.