Direct nonoxidative conversion of methane to hydrogen and higher hydrocarbons by dielectric barrier discharge plasma with plasma catalysis promoters

Direct nonoxidative conversion of methane to hydrogen and hydrocarbons was achieved at atmospheric pressure and 120 degrees C using nonthermal plasma sustained by plasma catalysis promoters (PCPs). Reactors had two different electrode configurations. Methane conversion correlated well with the specific energy density (SED). Methane conversion was independent of plasma power, flow rate, electrode configuration, or the type of PCPs. Hydrogen selectivity (ca. 60%) was dependent significantly on PCP and electrode configuration. The ethane/ethylene molar ratio increased from 0 to 0.15 with increasing SED. When the SED value was below ca. 100 kJ/L, ethylene was the only C-2 hydrocarbon. These results are similar to the recently reported nonoxidative catalytic methane conversion at ca. 1000 degrees C. Therefore, these results represent process intensification in methane conversion. PCPs underwent structural and chemical changes but their performances are not affected during an 80-h experimental period. (c) 2017 American Institute of Chemical Engineers AIChE J, 63: 4418-4429, 2017