Study on the conversion of CH4 and CO2 using a pulsed microwave plasma under atmospheric pressure

A conventional wire-like plasma enhanced and spread by pulsed microwave was used to study the oxidative coupling and reforming of CH4 with CO2 to CO, C2H2, C2H4 and H-2. Under the conditions of atmospheric pressure, flow rate of 200 mL/min (CH4/CO2 = 1.5 : 1), peak microwave power of 120 W and pulse duty factor of 100/100 ms, conversions of CH4 and CO2 were 70. 8% and 68. 8%, respectively; selectivities of CO, C2H2, C2H4 were 75%, 17. 8% and 4. 1%, respectively, and there was no carbon deposits. Ratio of H-2/CO increased with increasing CH4 concentration in the feed gas, and a H-2/CO ratio of 2 could be obtained at a ratio 2 : 1 of CH4 to CO2, which is acceptable for Fischer-Tropsch and other synthesis processes. The energy efficiency of the pulsed microwave plasma was obviously improved. We suggested that this enhanced pulsed plasma is useful for oxidative coupling and reforming of CH4 with CO2 in C1 chemistry.