Dynamic modelling and performance analysis of reversible solid oxide fuel cell with syngas

Reversible solid oxide fuel cell (rSOFC) is able to both generate and store energy in a single device under dual-mode operation conditions, i.e., fuel cell and electrolysis, which is favorable for intermittent energy supply and storage in application of renewable energies. The dynamic behaviors such as quick startup, short response time and good stabilization performance are highly required to optimize the performance in the dual-mode conditions, which has not been investigated well in consideration of the co-redox reactions with syngas. In this work, a 2D unsteady planar rSOFC cell model is developed with the experimental validation performed, to evaluate the dynamic behaviors in terms of multi-physics transport processes coupled with the co-redox reactions occurring in the rSOFC. The dynamic characteristics such as the long term performance, quick response and good stabilization are investigated by changing the working conditions including the starting-up and mode-switching procedures. It is concluded that the diffusion of the gases is the major limitation on the dynamic performance. The response and stabilization performance when the syngas is applied is not as good as that of H2/H2O fueled. It takes long time for the water-gas shift reaction to response and stabilize when the mode is switched in dual-mode work. The dynamic performance of the electrochemical reaction with responding current density is obviously affected with the fluctuant variation of the operating voltage for the case with syngas under dual-mode work. High temperature condition is beneficial to improve the quick response performance in dual-mode operation.