On design of plasma jet reactor for non-oxidative methane conversion

Non-oxidative methane coupling in an atmospheric pressure plasma jet reactor with an internal diameter of 3.0 mm has been studied. The jet reactor consisted of a quartz tube surrounded by a copper ring and a stainless-steel tube, which were separated by a variable distance. The stainless-steel tube (inner diameter: 1.0 mm, outer diameter: 1.5 mm) served as high voltage electrode and gas inlet. The jet characteristics with different tip angles of the high voltage electrode were investigated using voltage-current waveforms and gas analysis at a constant methane flow rate of 100 ml min−1. The effect of the length of the ground electrode and the gap between the electrodes on conversion, C2 selectivity and energy efficiency has been studied. The methane conversion was nearly tripled with a sharp angle of the electrode (15°), while the energy consumption was reduced from 150 to 55 kJ molC2Hy−1. The carbon deposition was also reduced.