Dilution effect with inert gases in direct synthesis of methanol from methane using nonthermal plasma

Direct synthesis of methanol from CH4 and O-2 has been experimentally studi ed using pulsed discharge plasma in a concentric-cylinder-type reactor. The methanol production was enhanced by dilution of source gas with inert gas, such as Ar and He. The methanol production became about 2.5 times larger a t the dilution ratio of 2.5, and gradually decreased with increase of the d ilution ratio and decrease of O-2 partial pressure. C2H6 was formed as one of the by-products, and its concentration increased with the increase of th e dilution ratio. This tendency was the same for Ar and He. When the partia l pressure of O-2 was kept constant, on the other hand, the methanol produc tion increased and saturated with the increasing of the dilution, but conce ntration of C2H6 stayed about the same level. Reaction selectivity of the m ethanol synthesis depended on the dilution ratio of the inert gas.