Multi-physics modeling assisted design of non-coking anode for planar solid oxide fuel cell fueled by low steam methane

Abstract

Internal reformation of low steam methane fuel is highly beneficial for improving the energy efficiency and reducing the system complexity and cost of solid oxide fuel cells (SOFCs). However, anode coking for the Ni-based anode should be prevented before the technology becomes a reality. A multi-physics fully coupled model is employed to simulate the operations of SOFCs fueled by low steam methane. The multi-physics model produces I-V relations that are in excellent agreement with the experimental results. The multi-physics model and the experimental non-coking current density deduced kinetic carbon activity criterion are used to examine the effect of operating parameters and the anode diffusion barrier layer on the propensity of carbon deposition. The interplays among the fuel utilization ratio, current generation, thickness of the barrier layer and the cell operating voltage are revealed. It is demonstrated that a barrier layer of 400 µm thickness is an optimal and safe anode design to achieve high power density and non-coking operations. The anode structure design can be very useful for the development of high efficiency and low cost SOFC technology.