Comparison of Graphical Tools for Targeting and Retrofit of Heat Exchanger Networks

Abstract

Depleting fossil and water resources, increasing environmental concerns and energy prices provide the impetus to continually improve heat integration in existing process plants. Four new graphical tools with potential to guide Heat Exchanger Network (HEN) design and retrofit are reported in literatures since 2010. These tools include Stream Temperature vs Enthalpy Plot (STEP) and HEat Allocation and Targeting (HEAT) for simultaneously targeting and design of a HEN, Energy Transfer Diagram (ETD) to capture the flowrate of heat transferred from the heating utilities to the environment through each heat-exchanger and process units as a function of temperature, Heat Exchanger Load Diagram (HELD) to identify heat-exchanger configuration. All these graphical tools are concisely explained and applied to guide the design and retrofit of a HEN problem. Compared with the traditional Composite Curve (CC) and Grid Diagram (GD), the advantages and disadvantages of each tool are compared and summarized. Suggestions to make a choice are provided.