Reactivity of methane in nonthermal plasma in the presence of oxygen and inert gases at atmospheric pressure

Partial oxidation of methane to methanol and formaldehyde as liquid fuels with oxygen diluted with inert gases was investigated experimentally using the pulsed discharge plasma method under conditions of room temperature and atmospheric pressure. The experimental results indicated that ethylene (C₂H₄), ethane (C₂ H₆), methanol (CH₃OH), formaldehyde (HCHO), hydrogen (H₂), water (H₂O), carbon monoxide (CO), and carbon dioxide (CO₂) were detected as products and, especially, methanol, formaldehyde, and carbon monoxide were the major products of the plasma chemical reactions. Particularly, it was found that the methanol and formaldehyde production has an optimum specific input energy (SIE: defined as the electrical applied energy per unit volume). The highest methanol and formaldehyde production ability and selectivity were achieved with a relatively low SEE of 360 J/L and concentration of Argon of 50 vol.%. Under this optimum condition, the maximum liquid fuel (methanol and formaldehyde) production ability of about 0.7 μmole/J, and selectivity of 64 mol%, were obtained