Assessing validity of model assumptions in co-electrolysis simulation

This research develops and validates a quasi-2D solid-oxide cell model for co-electrolysis and addresses critical modeling challenges. The model incorporates gas flow, Butler–Volmer electrochemistry, and the Dusty Gas Model for diffusion calculations. It assumes isothermal operation, confines electrochemistry to H 2 O splitting, restricts electrochemical reactions to the electrode–electrolyte interfaces, and gas-phase chemistry to the channels. The model is validated against data from a commercial Elcogen ASC-300C cell operated under various fuel compositions at 800 °C. Central model parameters governing activation and concentration overpotentials are fitted to the experiments, and the resulting estimates align well with literature values. The study finds that such a simple model provides accurate predictions for fuel mixtures with H 2 O-to-CO 2 ratios above 0.55 at water-gas-shift equilibrium, a range which covers most relevant industrial co-electrolysis applications such as methanation and Fischer–Tropsch synthesis. • A quasi-2D model to simulate co-electrolysis is developed. • Validation is conducted across a range of H 2 O-to-CO 2 ratios. • Central model parameters are estimated and align with literature values. • Model simplifications are assessed for their validity.