Advanced Exergetic Analysis of Chemical Processes

In this paper, a steam methane reforming (SMR) process for the production of hydrogen is studied. The process is based on two chemical reactions (reforming and water-gas-shift reaction). For each component but especially focusing on the chemical reactors, the avoidable part of the exergy destruction is estimated. The assumptions required for these calculations are discussed in detail and represent the main contribution of this work to the development of exergy-based methods for the analysis of chemical processes. In an advanced exergy analysis, the exergy destruction within a component is split into avoidable/unavoidable parts. This splitting improves understanding of the sources of thermodynamic inefficiencies and facilitates a subsequent optimization of the overall process. The overall SMR process is characterized by high energetic and exergetic efficiencies. However, the majority of the exergy destruction is caused by the irreversibility of chemical reactions and heat transfer. Results of this paper suggest options for improving the efficiency of the overall process.