Modeling of direct carbon solid oxide fuel cell for CO and electricity cogeneration

Direct carbon solid oxide fuel cell (DC-SOFC) is a promising energy conversion device for power generation using solid carbon fuel. In this paper, a 2D model is developed for a tubular DC-SOFC for CO and electricity co-generation. Parametric simulations are conducted to understand the physical/chemical processes in the DC-SOFC. Good performance of DC-SOFC is observed even at a large distance between the carbon bed and the porous anode, indicating the feasibility of large-scale DC-SOFC applications. The DC-SOFC performance is found to decrease with decreasing temperature due to the decreased Boudouard reaction kinetics. It's also found that the molar fraction of CO at the anode can be well controlled by adjusting the operating conditions, enabling DC-SOFC for electricity and CO cogeneration. Another finding is that the current density in the DC-SOFC increases slightly along the cell length, which is different from the H2-fueled SOFC. In addition, the anode-supported configuration is found to be beneficial in improving the electrical output of the DC-SOFC but is unfavorable for CO generation. A small Dce and a high potential are recommended to improve CO generation from the DC-SOFC. The model can be used for design optimization of DC-SOFC at a system level.