Direct Methane Conversion to Acetylene and Ethylene in a Corona Discharge Reactor: Energy Evaluation

Methane was directly converted to ethylene، acetylene، and synthesis gas using non-equilibrium plasma. The process was performed at room temperature and atmospheric pressure employing a quarts tube reactor with an outer diameter of 9 mm and an ac electrical discharge of 50 Hertz. Methane conversion was normally more than 50% with high selectivity to C2 hydrocarbons and synthesis gas. The experimental results show that، by applying higher voltages to the reactor، the conversion of methane and oxygen was increased. High selectivity to acetylene and synthesis gas was obtained at a higher level of voltage applied to the electrodes of the discharge zone. Introducing He to the feed stream enhanced the conversion of CH4 and O2; in this condition the yield of C2 hydrocarbons was as high as 27% with the energy efficiency of 0. 26 mmol/kJ، which was the highest value obtained in this study. When CH4 partial pressure was increased in the feed it caused a decrease in the overall methane conversion while increased selectivity to acetylene productions. The energy efficiency was improved smoothly by increasing the CH4 partial pressure. Finally، the interactions of high energy electrons with various species available in non- thermal plasma were thoroughly discussed.