Up to recently 2-D solid oxide fuel cell (SOFC) modelling efforts were based on global kinetic approaches for the methane steam reforming and water gas shift reactions (WGS) or thermodynamic equilibrium. Lately detailed models for elementary heterogeneous chemical kinetics of reforming (HCR) over Ni–YSZ anode became available in literature. Both approaches were employed in a quasi 2-D model of a planar high temperature electrolyte supported (ESC) SOFC and simulations were carried out for three different fuel gas compositions: pre-reformed natural gas (high CH4 content), and two different biomass derived producer gases (low CH4 content). The results show that the HCR predicts much slower reforming rates which leads to a more evenly distributed solid temperature but smaller power output and thus electrical efficiency. The two models result into predictions that differ greatly if high methane content fuels are used and for such cases the decision upon the modelling scheme to follow should be based on experimental investigations.
Keywords: Modelling, SOFC, Heterogeneous kinetics, Global kinetics