抄録
This paper presents an experimental study on decomposition of toluene gas in humid air using repetitive surface discharges on a dielectric barrier. Three kinds of voltages, polarity-reversed pulse with 50 ns of rise time, ac square with 0.1 ms of rise time and ac 50 Hz sinusoidal, are applied to a plasma reactor with a glass barrier between wire-plane electrode system. Experiments are done in two cases. In the first experiment, surface discharge light is observed by a still camera. Results of the photographic observation indicate that the light intensity for the polarity-reversed pulse voltage is much higher than those for the ac voltages not only under the dry condition but also under the humid conditions. It is remarked that no discharge light is observed for the ac sinusoidal voltage under the humid condition above 50 %R.H.. In the second experiment, toluene removal ratio and energy efficiency of toluene decomposition for a humid air including with 300 ppm gas-phased toluene are measured. Under a dry condition, there are no remarkable differences of the energy efficiency for toluene decomposition between the voltage waveforms. Under humid conditions, however, the energy efficiency for the ac voltages becomes lower than that for the polarity-reversed pulse voltage. The relationships between the toluene removal ratio and the consumed power can be simulated by an exponential function including geometry factor γ and discharge inception power P0. We conclude that the surface discharge treatment by the very-fast polarity-reversed pulse is an effective way for toluene decomposition under humid conditions.
