US EPA

1170338 

Book/Book Chapter 

Conversion of methane to higher hydrocarbons using non-thermal plasma 

Okumoto, M; Kim, HH; Takashima, K; Katsura, S; Mizuno, A; IEEE; IEEE 

2000 

IEEE INDUSTRY APPLICATIONS SOCIETY ANNUAL MEETING 

636-640 

WOS:000166107300102 

This study examines the conversion of methane to methanol and other higher hydrocarbons using non-thermal plasma generated by pulsed discharge. A coaxial-type plasma reactor with a glass dielectric interposed between the wire and the cylinder electrodes was used. A sharp-rising square wave pulsed voltage was used with a rising time of 50 ns and peak voltage of about 20 kV. Methane, Oxygen and Argon were mixed and fed to the reactor.



The experimental results indicated that ethylene (C2H4), ethane (C2H6), methanol (CH3OH), formaldehyde (HCHO), hydrogen (H-2), carbon monoxide (CO) and carbon dioxide (CO2) were the major products of the plasma chemical reactions. Effect of the parameters gas residence time, input power, and partial pressure of argon were studies experimentally. The production efficiency and the selectivity of products (ratio of number of molecules converted from methane to products) were greatly dependent on these parameters. Particularly, it was found that the methanol and formaldehyde production have an optimum specific input power. The highest methanol and formaldehyde production efficiency and selectivity were achieved for a methane and oxygen ratio of 85/15, partial pressure of Argon of 50 kPa and input energy of 1.2 kJ/L. This maximum production efficiency, of about 3.0 muL/J, and selectivity of 52% were obtained at the optimum conditions.