Mathematical modeling of solid oxide fuel cell performance with indirect internal reforming and thermal interaction analysis

Solid oxide fuel cells (SOFCs) are promising for efficient and sustainable energy conversion. However, carbon deposition and thermal stress pose significant challenges, particularly in indirect internal reforming (IIR) configurations. This study aims to develop a comprehensive mathematical model for an IIR-SOFC that operates on natural gas. The model incorporates a dual-layer electrode design to enhance diffusion and reaction processes. It employs a steady-state pseudo-homogeneous two-dimensional tubular structure and integrates momentum, mass, energy, and electrochemical processes. The model is simulated using COMSOL Multiphysics, and its accuracy is validated against experimental data. The analysis examines the impact of airflow rate, air ratio, working pressure, fuel flow rate, and fuel utilization on cell performance. Optimal conditions are identified as a working pressure range of 1-5 atm, an airflow rate of 0.75 mol h- 1, an air ratio of 6-12, a fuel flow rate of 0.072 mol h- 1, and a fuel utilization between 60-80%. The dual-layer electrode design enhances gas diffusion and electrochemical reactions, resulting in a 15% increase in voltage and a 10% increase in power output compared to single-layer electrodes. It also decreases concentration overpotential and carbon deposition by 15%, thereby mitigating thermal stress and improving cell durability. Moreover, co-flow configurations outperform counterflow configurations in thermal management by effectively reducing temperature gradients and thermal stress. These findings contribute to the optimization of SOFC designs, enhancing efficiency and longevity for sustainable energy applications.