Study On The Influence Mechanism Of Flow Channel Form On The Co-electrolysis Performance Of Solid Oxide Electrolysis Cell

Energy is an important resource for human survival.With the development of society,traditional energy faces a series of problems,such as energy depletion,environmental pollution,excessive emissions of greenhouse gas CO₂,global warming.The development of new energy sources such as wind energy and solar energy is expected to alleviate the problems of traditional energy sources.However,problems such as high light rejection rate,wind rejection rate,inability to connect to the grid and waste of electricity can seriously restrict the development of new energy.Solid oxide electrolysis cell?SOEC?is a new type of electrolysis cell that scholars pay more attention to in recent years.The co-electrolysis of H₂O and CO₂ to prepare H₂ and CO by SOEC is excepted to become an important way for capturing and utilizing CO₂,effectively utilizing new energy and realizing energy storage.At present,SOEC co-electrolysis technology is still immature,and the analysis of co-electrolysis performance and the methods to improve co-electrolysis performance are still the focus of scholars.Simulation is an important means to study new technologies.It is of great significance for the experimental research and development of co-electrolysis to establish a model to analyze the performance of co-electrolysis.Based on the research of co-electrolysis,this paper analyzes the method theory used in experiments and simulation studies,and establishes a three-dimensional integrated co-electrolysis model coupled with thermodynamics,electrochemistry and fluid mechanics which less research has been done.The model considers the conservation of mass,momentum,energy and the main electrochemical reactions,and analyzes the performance of co-electrolysis in the three-dimensional model.The flow field,temperature field and composition distribution of the system were analyzed in the simulation results,and the effects of hydrogen electrode and oxygen electrode on co-electrolysis were compared under different operating conditions.In addition,in the multi-channel structure,the influence of different flow channel forms on co-electrolysis is still unclear.In this paper,a multi-channel plate co-electrolysis model is established to compare the effects of the co-flow,counter-flow and cross-flow channels of monomer co-electrolysis and multi-channel co-electrolysis,respectively,so as to provide reference for experimental research.The simulation results show that in the co-electrolysis process,the gas flow rate in the center of the channel is higher,while the gas flow rate in the edge and the electrode is lower.The gas distribution of each component is basically that the concentration of reactant gas decreases gradually along the channel,and the concentration in the electrode is lower at the same cross section,while the product gas is the opposite.The gas flow rate of hydrogen electrode has a great influence on the conversion rate of co-electrolysis gas.The higher the flow rate,the lower the conversion rate.However,when the flow rate increases,the total gas production will have a rapid rise stage,and then the rise slows down,and the influence of the gas flow rate of oxygen electrode is small.Among the influence of the co-flow,counter-flow and cross-flow channels,the monomer counter-flow channel is better than the co-flow type,but the difference is small.In the multi-channel comparison,the current density distribution of the cross-flow channel is higher and uniform,and the overall performance is better.According to the simulation results in this paper,different distributions have their own characteristics in the process of co-electrolysis,and the operating conditions have a greater impact on co-electrolysis.In addition,although the flow channel form has little effect on the co-electrolysis performance compared with the material and operating conditions,it is still a convenient and effective way to improve the performance of co-electrolysis by changing the flow channel form appropriately.