(47d) A Multiphase CFD Model for Electrochemical CO2 Conversion in a Zero-Gap Membrane-Electrode Assembly Electrolyzer

As part of the pathway to net zero carbon economy, the electrochemical conversion of CO2 to different valuable chemicals and fuels using zero-gap membrane-electrode assembly electrolyzers received a significant attention in recent years. However, considerable activity improvement of this technology requires comprehensive studies on the catalyst characterization, cell configuration and operating conditions and flow parameters to achieve effective CO₂ conversion process. The flow behavior and interaction between the liquid and gas phase play crucial role in the performance, selectivity and the stability of the process. Thus, experimentally verified 3-D multiphase model and numerical simulation of CO2 electrolyzers are needed for optimum design, operation and scale up purposes. In this study, the mixture model was used to develop a two-phase steady-state CFD simulation to predict the behavior of gas-liquid flow in the cathode side of a zero-gap CO₂ electrolyzer. The model was also integrated with the chemical and electrochemical equations to predict the current-voltage behavior of the cell, as well as the rate of produced species. The results are validated against the existing experimental data from a lab-scale proof of concept electrolyzer. The developed model can be used to predict the effect of various operating parameters and scale up of this technology.