2D thermal modeling of a solid oxide electrolyzer cell (SOEC) for syngas production by H₂O/ CO₂ co-electrolysis

Abstract

Solid oxide fuel cells (SOFCs) can be operated in a reversed mode as electrolyzer cells for electrolysis of H₂O and CO₂. In this paper, a 2D thermal model is developed to study the heat/mass transfer and chemical/electrochemical reactions in a solid oxide electrolyzer cell (SOEC) for H₂O/ CO₂ co-electrolysis. The model is based on 3 sub-models: a computational fluid dynamics (CFD) model describing the fluid flow and heat/mass transfer; an electrochemical model relating the current density and operating potential; and a chemical model describing the reversible water gas shift reaction (WGSR) and reversible methanation reaction. It is found that reversible methanation and reforming reactions are not favored in H₂O/ CO₂ co-electrolysis. For comparison, the reversible WGSR can significantly influence the co-electrolysis behavior. The effects of inlet temperature and inlet gas composition on H₂O/ CO₂ co-electrolysis are simulated and discussed.