Thermal flow characteristics and the methane conversion reaction in a low power arc plasma reactor for efficient storage and transport of methane,which is the main component of shale gas,were simulated.The temperature...Thermal flow characteristics and the methane conversion reaction in a low power arc plasma reactor for efficient storage and transport of methane,which is the main component of shale gas,were simulated.The temperature and velocity distributions were calculated according to the type of discharge gases and arc current level by a self-developed magnetohydrodynamics (MHD)code and a commercial ANSYS-FLUENT code;the transport of chemical species was analyzed as including the chemical reactions of methane conversion.The simulated results were verified by the comparison of calculated and measured arc voltages with permissible low error as under 4%.Three C2 hydrocarbon gases with ethane (C2H6),ethylene (C2H4),and acetylene (C2H2)were selected as the converted species of methane from experimental data.The mass fraction of C2 hydrocarbons and hydrogen as the product of the conversion reaction at the reactor was also calculated.Those values show good agreement with the actual experimental results in that the major conversion reaction occurred in C2H2 and hydrogen,and the conversions to C2H6,C2H4,and hydrogen were minor reactions of methane pyrolysis conversion.展开更多
CF4 gas emitted in the semiconductor and display manufacturing process is a very harmful greenhouse gas.It must be removed or converted safely due to its extreme toxicity.Although a CF4 decomposition system using a th...CF4 gas emitted in the semiconductor and display manufacturing process is a very harmful greenhouse gas.It must be removed or converted safely due to its extreme toxicity.Although a CF4 decomposition system using a thermal plasma scrubber was commercialized,its removal efficiency is limited.In this work,a numerical analysis of CF4 decomposition in the thermal plasma scrubber was carried out in order to propose an efficient decomposition environment.The decomposition and recombination temperatures of CF4 were analyzed using thermodynamic equilibrium calculations.The chemical reaction of CF4 decomposition into carbon and fluorine gas was considered in this numerical analysis.The injection position and angle of the CF4 were controlled in order to enhance the decomposition rate.The vertical injection of CF4 near the torch exit improved the mixing of the CF4 with the thermal plasma flame.In addition,it was confirmed that the high temperature region expanded due to a vortex generated by strong turbulence in the bottleneck-shaped reactor.As a result,it is revealed that the CF4 injection location and the reactor configuration are the most important factors in improving the decomposition rate.展开更多
文摘Thermal flow characteristics and the methane conversion reaction in a low power arc plasma reactor for efficient storage and transport of methane,which is the main component of shale gas,were simulated.The temperature and velocity distributions were calculated according to the type of discharge gases and arc current level by a self-developed magnetohydrodynamics (MHD)code and a commercial ANSYS-FLUENT code;the transport of chemical species was analyzed as including the chemical reactions of methane conversion.The simulated results were verified by the comparison of calculated and measured arc voltages with permissible low error as under 4%.Three C2 hydrocarbon gases with ethane (C2H6),ethylene (C2H4),and acetylene (C2H2)were selected as the converted species of methane from experimental data.The mass fraction of C2 hydrocarbons and hydrogen as the product of the conversion reaction at the reactor was also calculated.Those values show good agreement with the actual experimental results in that the major conversion reaction occurred in C2H2 and hydrogen,and the conversions to C2H6,C2H4,and hydrogen were minor reactions of methane pyrolysis conversion.
文摘CF4 gas emitted in the semiconductor and display manufacturing process is a very harmful greenhouse gas.It must be removed or converted safely due to its extreme toxicity.Although a CF4 decomposition system using a thermal plasma scrubber was commercialized,its removal efficiency is limited.In this work,a numerical analysis of CF4 decomposition in the thermal plasma scrubber was carried out in order to propose an efficient decomposition environment.The decomposition and recombination temperatures of CF4 were analyzed using thermodynamic equilibrium calculations.The chemical reaction of CF4 decomposition into carbon and fluorine gas was considered in this numerical analysis.The injection position and angle of the CF4 were controlled in order to enhance the decomposition rate.The vertical injection of CF4 near the torch exit improved the mixing of the CF4 with the thermal plasma flame.In addition,it was confirmed that the high temperature region expanded due to a vortex generated by strong turbulence in the bottleneck-shaped reactor.As a result,it is revealed that the CF4 injection location and the reactor configuration are the most important factors in improving the decomposition rate.
