High temperature co-electrolysis of H2O and CO2 offers a promising means for syngas production via efficient use of heat and electricity [1, 2]. Some of the considerable advantages to this technology include high reaction kinetics, reduced cell resistance, lowered probability of carbon formation, possibility of coupling with Fischer-Tropsch process for conversion of syngas to liquid fuel/hydrocarbons, effective utilization of heat from exothermic water-gas shift reaction and less complexity at the systems level due to the lack of need for a separate water-gas shift reactor. In this analysis, we report an in-house model to describe the complex fundamental and functional interactions between various internal physico-chemical phenomena of a SOEC. Electrochemistry at the three-phase boundary is modeled using a modified Butler-Volmer (B-V) approach that considers H2 and CO, individually, as electrochemically active species. Also, a 42-step elementary heterogeneous reaction mechanism for the thermo-catalytic H2 electrode chemistry, dusty gas model to account for multi-component diffusion through porous media, and plug flow model for flow through the channels are used. The model is geometry independent. Results pertaining to detailed chemical processes within the cathode, electrochemical behavior and losses during SOEC operation are demonstrated. Reaction flow analysis is performed to study methane production characteristics during co-electrolysis. Simulations are carried out for configurations ranging from simple 1D electrochemical cells to quasi-2D unit cells, to elucidate the effectiveness of the tool for performance and design optimization. The article pertaining to this study is/will be published elsewhere [3].
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