Methane conversion into aromatics in a direct plasma-catalytic process

The conversion of methane to aromatic hydrocarbons was investigated in a pulsed microwave plasma at atmospheric pressure in the presence of a heterogeneous catalyst. The influence of the microwave power and methane flow rate or residence time, respectively, on the conversion degree and product concentration was analyzed. The methane conversion reached 60-70%. Higher hydrocarbons were produced, with C-2 being the most abundant. Only after initial carbon formation in the discharge were aromatic products observed. The solid carbon catalyzed the methane aromatization. Benzene was the main aromatic product formed, in concentrations up to 0.6%, with selectivities up to approximately 30%. (C) 2002 Elsevier Science (USA).