Heat Exchanger Network synthesis considering prohibited and restricted matches

Abstract

In the industry, there are frequently prohibited and restricted matches in the Heat Exchanger Networks (HENs). These matches could cause risk cost when failures happen. Some matches of streams can be entirely prohibited, but some may only have a certain level of restriction. The margins are set up, based on the risk cost assessment, whether to exchange the heat and by which type of equipment between specific streams. This study proposes a method based on the Advanced Grid Diagram to benefit from an optimised synthesis plan for HEN considering prohibited and restricted matches. A pre-designed HEN could be determined in the synthesis stage, not considering the prohibited or restricted matches. A follow-up topology evolution is performed to trade off the prohibitions and evaluate the restrictions. A Benefit Diagram has been developed to show how many economic benefits can be gained by implementing new heat exchangers. It is used for comparison between allowing all restricted streams and avoiding restricted streams to find the potential risk cost margin. The method is applied to a case study to analyse the restricted and prohibited matches. Optimal HEN design results offer the designers a guide to evaluate to which extent should implement the restricted matches.