Combined steam reforming and partial oxidation of CO₂-containing natural gas in an AC gliding arc discharge system

Abstract

Conventional catalytic processes for converting CH₄ to synthesis gas require both high temperature and high pressure. Partial oxidation of methane is another way to solve the problems. In this work, a technique of combining steam reforming with partial oxidation of CO₂-containing natural gas in gliding arc discharge plasma was investigated. The effects of several operating parameters, including hydrocarbons (HCs)/O₂ feed molar ratio, applied voltage, input frequency, and electrode gap distance, on reactant conversions, product selectivities and yields, and power consumptions were examined. The results showed an increase in both CH₄ conversion and synthesis gas yield with increasing applied voltage and electrode gap distance, where the opposite trends were observed with increasing HCs/O₂ feed molar ratio and input frequency. The optimum conditions were found at a HCs/O₂ feed molar ratio of 2/1, an applied voltage of 14.5 kV, an input frequency of 300 Hz, and an electrode gap distance of 7 mm, providing high CH₄ and O₂ conversions with high synthesis gas selectivity and very low power consumptions. Under these optimum conditions, the power consumptions were as low as 2.04x10‾¹⁸ Ws (12.72 eV) per molecule of produced hydrogen.