4E analysis of an integrated system of catalytic distillation dehydrogenation system of perhydro benzyltoluene and solid oxide fuel cell

Abstract

This study proposes integrating the catalytic distillation dehydrogenation system with a solid oxide fuel cell (SOFC) system to recover and reuse the waste heat from the SOFC exhaust gases. The research focuses on a 25 kW SOFC system and categorizes potential system layouts into three types based on the final use of the exhaust gas. Through a comprehensive analysis from energy, environmental, economic and exergy (4E) perspectives, the results show that while the SOFC stack dominates the energy and economic factors, leading to consistent performance across similar system layouts, the thermodynamic irreversibility during system operation is influenced by exergy destruction and exergy loss. Using a multi-criteria evaluation approach, the optimal integration scheme, where the final exhaust gas is utilized for preheating air, was identified when all four indicators were equally weighted. The results indicate that the optimal system achieves a thermal efficiency of 46.97% and improves system energy efficiency by 52.59%. Furthermore, compared to the initial non-integrated system, the integrated system reduces environmental carbon emissions by 58.56%, increases economic efficiency by 36.64% and reduces exergy losses by 94.11%, highlighting the advantages of system integration. More importantly, the integrated system has a competitive levelized cost of electricity (LCOE) of 0.134 $/kWh, demonstrating its potential for a wide range of applications, from small-scale to large industrial processes.