Critical evaluation of an automated tool for heat exchanger network retrofits based on pinch analysis and the Matrix method

Abstract

The current climate change concern comes with new energy efficiency regulations. In order to reach these new targets but also to get a more profitable process, plants have to reconsider the design of their heat exchanger networks to reduce heat losses. One way to proceed consists of retrofitting the network using the Matrix method in order to get the cheapest solution achieving a defined level of heat savings. The software Matrix.xla has been developed to run such a method. The main task of this thesis is to analyze the accuracy of the results given by the method and the software. The theoretical methodology behind the Matrix method is explained. The working procedure of program Matrix.xla is enlightened and tested on specific examples to point out several issues. Among these concerns, merging of the final solution, introduction of split streams and handling utility streams are further investigated. A complete solution is produced for the merging. However, given the complexity of the splitting issue, only one specific solution is developed together with some highlights of how to proceed for a general one. Concerning the utilities, a complete solution is elaborated. Nevertheless, this solution can be pushed further by modifying some concepts inside the Matrix method. Several ideas explaining how to proceed in this direction are described. This work brings a better understanding of how a retrofit is identified by the automated Matrix method tool and brings solutions to improve its and the Matrix method’s routine. This is done in order to increase the applicability and reliability of the Matrix method and the automated tool to identify better retrofit solutions.