Near-zero emission trigeneration system coupling molten salt methane pyrolysis with solid oxide fuel cell based on carbon capture and utilization: Thermodynamic and exergoenvironmental evaluation

Abstract

Natural gas-based energy systems have garnered widespread attention for their potential to facilitate the transition from traditional to renewable energy sources. Among these, methane pyrolysis technology stands out as a promising pathway. Consequently, a novel methanol-electricity-carbon trigeneration system featuring methane pyrolysis coupled with chemical looping combustion, methanol synthesis, and solid oxide fuel cell unit was designed. To validate this innovative concept, thermodynamic model of the process was developed. Compared to conventional single-generation system, the proposed system demonstrated superior thermodynamic performance, with energy efficiency of 69.51 %, representing improvement of 28.78 %. Sensitivity analysis indicated that optimal carbon utilization-to-storage ratio of 0.68 effectively balanced environmental benefits with energy conversion efficiency. Additionally, the CO2 capture rate and emission of the proposed system reached impressive 99.24 % and 2.15 kg/MWh, respectively, confirming its carbon mitigation potential. Based on this, exergoenvironmental analysis demonstrated that rb,k of the novel system was 21.14 %, indicating room for further environmental impact reduction. Moreover, due to the high rb,k of 16.61 % for the preheater-2 identified as a key component for optimization. Finally, the economic analysis verified the system’s feasibility, showing the annual net income of 6774.06 k$. This novel concept highlights the potential of natural gas-based systems in optimizing carbon utilization and energy efficiency, contributing to a more environmentally sustainable energy infrastructure.