Anhydrous Polybenzimidazole-Based CO2 Electrolysis Using Computational Fluid Dynamics

CO₂ electrolysis has become an increasingly well studied method of using captured CO₂ from the atmosphere as a source of popular chemical feedstocks.¹ Additionally, it can be more time- and cost-efficient to model CO₂ electrolysis using computational fluid dynamics (CFD) before applying the calculated predictions to a lab setting. Current CO₂ electrolysis simulations use a NafionTM brand proton exchange membrane (PEM) and a liquid flow model², but this research investigates using a polybenzimidazole (PBI) membrane in a gas phase model. This membrane’s ability to function in high-temperature, anhydrous environments³ makes it a promising next step in the area of CO₂ electrolysis due to its possible increased efficiency. Furthermore, a gas phase simulation could allow for faster diffusion rates and less overpotential than a multiphase model⁴. Using Star-CCM+ as the CFD software, a geometry and meshing based on an actual, densified and 24-hour reimbibed, PBI electrolyzer cell were developed. Then, parameters from previous models^3,5, the literature⁶, given constants, and prediction calculations were input into the simulation. The electrolyzer’s performance in terms of species concentration distribution, potential distribution, current density distribution, temperature distribution, and pressure distribution were plotted and analyzed, as well as its polarization curves. Using this data, experiment design and predictions in the lab setting can become more precise; in return, lab results can be used to create a more accurate model for CO₂ electrolysis.

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