Renewable and high-concentration syngas production from oxidative reforming of simulated biogas with low energy cost in a plasma shade

•A novel plasma shade for oxidative reforming of biogas was reported.•Large reactive space formed by rotating spark channels was achieved.•Increase in conversions with SEI exhibited rapid and slow zones.•V-shape profile of syngas energy cost versus SEI was observed.•The optimal SEI was found for concentration and energy cost of syngas.

A novel plasma shade with large reactive space generated by rotating spark channels was used for the first time for oxidative reforming of simulated biogas (CH4:CO2:O2 = 3:2:2) to produce high-concentration syngas (CO + H2) with low energy cost. This unique plasma exhibited rapid- and slow-zones where the conversion of O2, CH4 and CO2 and dry-basis concentration of syngas (CCO+H2dry) changed at two significantly different paces with specific energy input (SEI). With increasing SEI  , the conversion and CCO+H2dry first increased rapidly at SEI < 84 kJ/mol, while the conversion and CCO+H2dry increased at a much slower pace at SEI > 84 kJ/mol. Moreover, V-shape profile of syngas energy cost (ECCO+H2ECCO+H2) versus SEI was observed. Thereby, the optimal SEI   was found at which the lowest ECCO+H2ECCO+H2 (1.0 eV/molecule) and a very high CCO+H2dry (73%) were simultaneously achieved. The good stability of the plasma reaction at the optimal SEI was verified over an 8-hour test.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slide