Canadian Journal of Chemical Engineering, Vol.81, No.1, 37-42, 2003
Oxidative coupling of methane in a negative DC corona reactor at low temperature
Oxidative coupling of methane, (OCM) in the presence of DC corona is reported in a narrow glass tube reactor at atmospheric pressure and at temperatures below 200degreesC. The corona is created by applying 2200V between a tip and a plate electrode 1.5 mm apart. The C-2 selectivity as well as the methane conversion are functions of methane-to-oxygen ratio, gas residence time, and electric current. At CH4/O-2 ratio of 5 and the residence time of about 30 ms, as C-2 yield of 23.1% has been achieved. The main products of this process are ethane, ethylene, acetylene as well as CO nad CO2 with CO/CO2 ratios as high as 25. It is proposed that methane is activated by electrophilic oxygen species to form methyl radicals and C-2 products are produced by a consecutive mechanism, whereas CO2 is formed during parallel reactions.