Improvement of Ozone Generation Characteristics with Shorter Rise Time of Nanosecond Pulse Voltage

Abstract

Ozone has a variety of positive characteristics such as strong oxidation power and non-residual toxicity; therefore, it is expected as one of the next-generation oxidants. There are various applications using ozone, for instance, clarification of drinking water, industrial wastewater treatment, and so on. At present, though ozone generation by a dielectric barrier discharge is the main method for commercial ozonizers, it has some disadvantage, which is a lower energy efficiency for plasma phase because the most of the input energy is lost as heat. In the recent years, the nanosecond pulsed power generator (NS-PG), which can generate a pulsed voltage with 5 ns duration have been developed, and the nanosecond (ns) pulsed discharge leads the higher energy efficiency of the ozone generation. However, there is still problems that the maximum ozone concentration using the nanosecond pulsed discharge has been saturated at approximately 40 g/m3. Therefore, the present study focused on improving the ozone generation characteristics using ns pulsed discharge generated with shorter rise time of ns pulse voltage. In the experiment, the pulse with shorter rise time was formed by a peaking gap switch which is newly developed, and the rise time is shortened into 2 ns (conventional type NS-PG: 3 ns). Finally, we investigated the effect of pulse rise time on ozone generation. As the result, in case of shorter rise time pulse, the efficiency of ozone generation is higher than that of the conventional type NS-PG.