A Rigorous Mechanism-Based Kinetic Modeling Method for Optimization of Solid Oxide Fuel Cell

Solid oxide fuel cells (SOFC) have gained increasing attention as they generate electricity with higher energy conversion efficiency. Current studies are focused on the rigorous mechanism development on the experimental scale or thermodynamic modeling for SOFC on the industrial scale. Given the practical application concerns, it is imperative to integrate the reaction mechanism with large-scale SOFC system optimization. Toward this goal, this paper proposes a novel mechanism-based kinetic modeling method for optimization of SOFC, which includes aspects of electrochemistry, diffusion phenomena, and microscale kinetic modeling. Two plug flow reactors are adopted to simulate the cathode and anode of the component stack, respectively. The reaction distance is differentiated, and the model is solved in each differential unit. The electrochemical process and internal methane reforming process in the anode are coupled through hydrogen allocation, and the oxygen in the cathode is optimized according to the microscale kinetic modeling in each differential unit. The accuracy of the model is verified by comparison with the results of simulation experiments in the literature, where the average relative error is about 5%. Sensitivity analysis is performed to recognize the key parameters and explore their effects on stack performance improvements. The result shows that the diameter of PFR has the larger effect on the voltage, the mole fraction of H2, H2O, and CH4, and the reaction time, compared with the length of PFR and the amount of catalyst. The major contributions derived from this work are of significant aid in providing guidelines for future development of kinetic modeling of other fuel cells.