3D Multi-physics Simulation Of Solid Oxide Fuel Cell For Coal-gasification Power Generation

Solid Oxide Fuel Cell(SOFC)is the core part of the Integrated Gasification Fuel Cell Cycle(IGFC)system,and it converts the chemical energy of fuels directly to electric energy.Besides,SOFC has an operating temperature of 1023-1123 K which provides a high fuel flexibility,and does not require expensive catalysts.In this paper,the heat and mass transfer mechanism of SOFC is studied by simulation means,which has important guiding significance in improving the overall performance of the cell and reducing the cost.A three-dimensional model of planar internal reforming SOFC is established.The multi-physics coupling process inside the cell is studied.The effects of pressure on the internal reforming reaction and the co-electrochemical oxidation are also considered.Firstly,the mechanism of working pressure on cell performance and internal physical field distribution is studied.The results show that increasing the pressure can improve the cell performance from the aspects of increasing open circuit voltage and reducing the activation overpotential,and simultaneously can enhance the electrochemical reaction in the vicinity of electrolyte.The pressurization can also affect the species distribution and the internal reforming reaction distribution.Under partial pre-reforming gas conditions,the elevated pressure will form a supercooled area,which increases the cell temperature gradient.In addition,the influence of intake air flux is studied.The reduction of fuel utilization rate under normal pressure can effectively control the temperature gradient of SOFC in partly pre-reformed gas conditions,but at the same time,the high pressure will deteriorate the performance of the cell.For syngas-fueled cells,the fuel utilization has no significant effect on temperature distribution.It is also possible to reduce the temperature gradient of the SOFC by increasing the cathode air ratio.Finally,this paper further develops the model to study the distribution of physical fields in different flow field configurations of multi-channel cells.The difference between the two flow configurations mainly comes from different temperature distributions.For counter-flow configuration,the temperature is higher near the air outlet and the temperature at the fuel outlet is lower,which makes the methane steam reforming reaction concentrated toward the fuel inlet.Internal reforming reactions also cause differences in mole fractions such as methane,carbon monoxide,and hydrogen.The lower temperature and fuel concentration at the fuel outlet in counter-flow configuration also reduce electrochemical reaction rates and affect the distribution of the activation overpotential.