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 (C 2 H 6 ), ethylene (C 2 H 4 ), and acetylene (C 2 H 2 ) 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 C 2 H 2 and hydrogen, and the conversions to C 2 H 6 , C 2 H 4 , and hydrogen were minor reactions of methane pyrolysis conversion.
Silicon appears as a promising candidate to replace the graphite anode for lithium ion batteries (LIBs) due to its extremely high charge capacity. However, the large volume expansion during charging leads to serious stability problems. Silicon nanoparticles coated with protective coatings are reliable to solve this problem and facilitate the practical implementation of the silicon anode. In this study, induction thermal plasma was applied to synthesize silicon nanoparticles with amorphous hydrogenated carbon coating, and the effects of additional carbon sources were investigated. A novel but simple injection method of hydrocarbons was introduced to limit the unfavorable formation of byproducts. The thickness of carbon coating ranges from 2 to 8 nm with a higher hydrocarbon gas flow rate, while silicon particles show a constant mean diameter of around 70 nm. The properties of carbon coating, like sp 2 ratio and H-content, are tunable, and the thermal decomposition mechanism of carbon sources is believed as a key factor. Graphene flakes can also be obtained with abundant carbon and hydrogen radicals released. Based on the material characterizations, acetylene is regarded as a better candidate to prepare carbon coating. The above results show significance for the design of next generation of LIBs.
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