The Experimental And Numerical Research Of Methane Steam Reforming In Plasma

CRGT is a new and advanced cycle of gas turbine. Chemical recuperator is a core component of it where the reforming reaction happened between methane and water vapor.The exhaust temperature of CRGT is500℃and the optimum temperature of methane steam reforming Ni-based catalysts is around700℃. Catalyst efficiency and the conversion rate of methane steam reforming is low when the chemical recuperator is designed in a conventional way. In addition, Shortages like oversize of the cooperator and deactivation of catalyst is also serious. low power consumption and no particulate pollutants can be regarded as the reason why the low-temperature plasma catalytic is used in this paper.Dielectric barrier discharge generator is designed in this paper and the experimental design and the relevant research about low-temperature plasma catalytic steam reforming is also conducted. Some factors like residence time, voltage, temperature and frequency are discussed as well. Experimental results are as follows:Low-temperature plasma catalytic methane steam reforming reaction can be steady when the residence time reach to0.71s. The ethane conversion rate is about26%. Simultaneously, methane can account for66.4%, carbon monoxide can account for2.7%,hydrogen can account for21.6%and high-carbon hydrocarbons can account for11%among the generation gas. With the increase of dielectric barrier discharge voltage and frequency, the methane conversion rate of low-temperature plasma catalytic methane steam reforming reaction is becoming larger. Hydrogen selectivity increases when the electric field intensity of dielectric barrier discharge air-gap increases; carbon monoxide selectivity decreases when the electric field intensity of the dielectric barrier discharge air-gap field intensity increases. There is no obvious connection between hydrogen selectivity and the frequency of dielectric barrier discharge; carbon monoxide selectivity decreases when the frequency of dielectric barrier discharge increases. There’s no interaction between the low-temperature plasma catalytic methane steam reforming reaction and temperature of the whole reaction system. The conclusion of the depth of reaction, the reaction selectivity, low calorific value increasement provide the data basis for the designe and improvement of plasma catalyzed chemical recuperator.A chemical model of low-temperature plasma catalytic methane steam reforming reaction is proposed in this paper and numerical research is also conducted with COMSOL Multiphysics. The simulation results can be matched with the experimental ones well.Numerical results are as follows:The variety of concentration of HCO evidently represents a periodic character. But there’s no evident changes in one period. The range of concentration variety increases with the increase of voltage, frequency and the gas gap.The variety of electricity field intensity represents a periodic feature. The distribution of electricity field is asymmetric. It increases with the increase of voltage and frequency. Electric field strength, the average electron energy increases when the voltage and frequency increases. Dielectric barrier discharge becomes more strongly with the increase of voltage and frequency, discharge current increases as well. However, larger discharge gap is unfavorable for the development of discharging. The calculation results reveals the physical and chemical processes of the low-temperature plasma catalytic methane steam reforming reaction in the respect of the microscopic and electrical characteristics.