Direct Carbon Solid Oxide Fuel Cell Design And Numerical Simulation Research

Direct carbon solid oxide fuel cells(DC-SOFC)can directly use solid carbon as fuel.Because of obvious advantages such as wide fuel sources and high efficiency,DC-SOFC has been widely concerned by scholars from various countries.Moreover,new ideas and technical means for clean,safe and efficient using of coal and various biomass are to be provided by DC-SOFC.Many studies have proved that the CO produced by the Boudouard reaction of solid carbon is the real fuel of DC-SOFC.However,the shortage of fuel gas CO is one of the key factors that lead to the decline of cell performance.The endothermic Bouduouard reaction is very sensitive to temperature,while the low-temperature region of DC-SOFC limits the Boudouard reaction rate and the performance of DC-SOFC.1.At present,few researchers have designed DC-SOFC to improve Boudouard reaction.In order to improve the Boudouard reaction rate in low-temperature region,this paper first proposes a DC-SOFC with an inserted hear bar in the anode carbon chamber,and explores the effect of heat bar thermal conductivity,radius and carbon chamber porosity on DC-SOFC.The results show that the inserted heat bar in the anode carbon chamber can quickly transfer heat from the top to the bottom of DC-SOFC,thereby greatly increasing the minimum temperature of the carbon chamber and the minimum CO mass fraction,a more uniform temperature distribution and CO distribution are benifitial to the long-term stable operation of DC-SOFC;the heat bar can also significantly enhance the Boudouard reaction rate and cell performance under a wide range of operating voltages,and the advantages are more pronounced at higher heat bar thermal conductivity or lower operating voltage;2.In order to increase the temperature of DC-SOFC at the air inlet,a DC-SOFC with an inserted air fin to form air inlet and outlet at one end is proposed considering the effect of the air flow mode on the basis of the inserted heat bar in the anode carbon chamber.The effect of air flow pattern on the performance of DC-SOFC is analysed,and the effect of air fin thermal conductivity,location and size parameters are further explored.The research shows that the high-temperature outflow air heats the low-temperature inflow air through the air fins,which increases the cell temperature at the air inlet.The minimum temperature and CO mass fraction of the DC-SOFC with air fin are greatly improved compared to the DC-SOFC without air fin.The uniform temperature field and species field are beneficial to reduce thermal stress and provide a guarantee for maintaining the stable operation ofDC-SOFC.In addition,in comparison to DC-SOFC with heat bar,DC-SOFC with air fin greatly improves Boudouard reaction rate and cell performance;low thermal conductivity,small size air fins and smaller air inlet width are more conducive to increase DC-SOFC performance.