Characteristics of the Discharge and Ozone Generation in Oxygen-Fed Coaxial DBD Using an Amplitude-Modulated AC Power Supply

Abstract

In this study, a traditional tubular reactor and an amplitude-modulated AC power supply were employed to develop a unique practical ozone generator with a widely adjustable ozone concentration and simultaneously a constant ozone yield. The characteristics regarding discharge and ozone generation in oxygen were experimentally investigated in detail. The amplitude-modulated AC waveform consisted of TON (burst of four consecutive AC cycles) and TOFF with a duty cycle of 0.4. The experimental results show that a unique ozone generator can be developed through changing the applied voltage amplitude when an amplitude-modulated AC power supply producing periodic bursts of several consecutive AC cycles during the TON period is used. A quite high and stable ozone yield of 165 ± 16 g/kWh was achieved and a wide range of ozone concentrations could be obtained. Moreover, we observed a very interesting phenomenon that the discharge energy and voltage peak for every AC cycle showed some difference, resulting from the accumulation and release of charge on the dielectric. The first AC cycle had the highest discharge energy and positive voltage peak as well as the lowest negative voltage peak, which was particularly obvious at a high energy density. Additionally, water cooling of the grounded electrode seemed to have a small influence on the basic electrical characteristics of the discharge and had a positive effect on the concentration and yield of ozone due to a reduction in gas temperature in the discharge gap.