Discharge in a Subthreshold Microwave Beam as an Effective Means for Mercaptan Decomposition

A subthreshold microwave discharge in atmospheric-pressure air is used to process mixtures of mercaptans (thiols) with air and with air and methane. It is found that, at microwave intensities of ~10 kW/cm² and pulse durations of 1–3 ms, the mercaptan concentration decreases 100-fold in mixtures with air and 20-fold in mixtures with air and methane. It is shown that, at an average specific energy deposition in a single discharge of ~0.4 J/cm³, the specific microwave energy spent on mercaptan decomposition is ~10 J/cm³. It is concluded that the active zone of the discharge with high specific energy deposition occupies less than 5% of the microwave beam volume.