Seigo Kameshima

One step methane conversion to syngas by dielectric barrier discharge

Direct conversion of CH4 to syngas (H2 and CO) via CH4 partial oxidation was investigated using a narrow-gap co-axial dielectric barrier discharge reactor. Partial oxidation is initiated by electron impact dissociation of CH4, while complete oxidation is suppressed due to low temperature condition (200–400 °C): CH4 conversion and selectivity for products were determined by the specific energy input (SEI) ambiguously, which is calculated by the input power (J/s) over the total flow rate (cm3/s), producing syngas via direct route with H2/CO = 0.8–1.3 and CO selectivity of 29–41%. However, H2 was oxidized rather preferentially which subsequently produces oxidative species such as H2O2, HOO, and OH; H2 oxidation was promoted by those species and H2 selectivity decreased markedly. Suppression of H2 oxidation is crucial issue to reach higher syngas yield with large H2/CO ratio.