Parametric analysis of solid oxide fuel cell fueled by syngas based on lattice Boltzmann method

During the operation progress of solid oxide fuel cell (SOFC), the performance and endurance are two major concerns significantly affected by gas flowing, charge transport, and chemical reaction. This paper presents a thorough research on the key parameters related to syngas and charge transport in the SOFC to reveal the intrinsic influence mechanism, including electro conductibility, gas mixture concentration, CH4 component ratio, temperature, and anode thickness, which is instrumental in improving the operational efficiency and applicability of SOFC. Firstly, the theoretical models of charge transport and multi-component mass transfer are established, respectively, and the two are coupled using the reaction rate calculation method. Then, employing an innovative combination of the representative elementary volume (REV) scale lattice Boltzmann method (LBM) and the finite-difference LBM, the potential and multi-component gases distributions are simulated to calculate the evaluated indicators, namely activation and concentration overpotential. Finally, considering various operational conditions, the simulation experiments are conducted to investigate the parametric effect on the performance of SOFC fueled by syngas. The results demonstrate that compared to the direct reforming way, the external syngas with lower CH4 component ratio is more favorable to the SOFC and the optimal ratio should be controlled within 0.2. The higher concentration of gas mixture and lower anode thickness both contribute to weakening the effect of concentration polarization. Especially, the performance of SOFC is improved when the concentration is 15 mol‧m−3 and the anode thickness is below 1.05 mm. With the increment of conductivity and operating temperature, the consumption of H2 gradually increases, enhancing the efficiency of reaction gas and reducing the economic cost. And the optimal operation temperature of SOFC is about 1073 K. Moreover, the anode thickness is a trade-off between the electrochemical reaction conditions of anode and cathode, as its variation affects both of them.