A Simple Case Study on Application in Synthesising a Feasible Heat Exchanger Network

Abstract

Heat exchanger network (HEN) is very important to optimise energy usage in process industry. Heat exchanger network synthesis is an important process synthesis problem where different tools and methods have been presented to solve this synthesis problem. In HEN synthesis, the feasibility of the HEN design is not taken into consideration. The HEN design may not be able to be implemented in industrial applications. It is essential to check the feasibility of a design before it is being implemented in the industry. The objective of this paper is to present the application of a new flexible and operable heat exchanger network (FNO HEN) methodology in synthesising a feasible HEN using a simple case study. The novelty of this work is to determine an optimal ?Tmin value that gives minimum external energy requirement (EER) and heat exchanger area (HEA) as well as simultaneously analyse the feasibility of the HEN design in an easy, systematic and efficient manner. Using the new developed FNO HEN methodology framework, HEN design target, which is the value of ?Tmin is determined to obtain the feasible HEN design. From process design point of view, ?Tmin value determines the size of heat exchanger in the network as well as energy saving. A process simulator is used to check the process feasibility of the HEN designs. With the use of the feasible HEN trade-off plot, which is a plot of EER and HEA at different value of ?Tmin with additional of feasibility area, the optimal feasible HEN design which satisfies external energy requirement (operability), heat exchanger area (capital) and process feasibility has been successfully determined.