A Green Process for High-Concentration Ethylene and Hydrogen Production from Methane in a Plasma-Followed-by-Catalyst Reactor

摘要

A green process for the oxygen-free conversion of methane to high-concentrationethylene and hydrogen in a plasina-followed-by-catalyst (PFC)reactor is presented.Withoutany catalysts and with pure methane used as the feed gas,a stable kilohertz spark dischargeleads to an acetylene yield of 64.1%,ethylene yield of 2.5% and hydrogen yield of 59.0% with80.0% of methane conversion at a methane flow rate of 50 cm^3/min and a specific input energy of38.4 kJ/L.In the effluent gas from a stable kilohertz spark discharge reactor,the concentrationsof acetylene,ethylene and hydrogen were 18.1%,0.7% and 66.9%,respectively.When catalystsPd-Ag/Si02 were employed in the second stage with discharge conditions same as in the case ofplasma alone,the PFC reactor provides an ethylene yield of 52.1% and hydrogen yield of 43.4%.The concentrations of ethylene and hydrogen in the effluent gas from the PFC reactor were foundto be as high as 17.1% and 62.6%,respectively.Moreover,no acetylene was detected in theeffluent gas.This means that a high concentration of ethylene and oxygen-free hydrogen can beco-produced directly from methane in the PFC reactor.