A systematic approach: combining process optimisation exergy analysis and energy recovery for a better efficiency of industrial processes

Abstract

Exergy analysis has been shown to be a powerful tool for assessing and improving the energy efficiency of thermal and chemical processes. However, the lack of systematic procedures in examining and interpreting the results of the exergy balance or the exergy efficiency makes this kind of analysis more or less limited to the academic world. This paper intends to promote an efficient energy usage through pinch, exergy analyses and energetic optimisation and by providing the engineer with specific improvement means by using a case-based reasoning (CBR) system. To make exergy analysis more understandable, it was decided to develop two methodological tools: a supporting graphical representation of the exergy analysis and a CBR system to help the user in developing alternatives. Both tools are grouped together into a general methodology for the analysis and retrofit design of industrial sites. This new approach is illustrated through an ammonia processing plant case study