Investigation of Energy Control in Coaxial Reactor for Ozone Production by Using Nanosecond Pulsed Power

Ozone has been used an oxidation agent in various fields, and production of ozone with high efficiency and high concentration is required. In this study, ozone is produced in coaxial reactors using nanosecond pulsed power discharges. The ozone production with pulsed power discharges is efficient but relatively low-concentrated. In our previous studies, the ozone concentration increased with decrease of the diameter of the coaxial reactor. However, ozone concentration decreased in reversal by further decrease of the diameter of reactor. The surplus energy of applied pulse on the reactor is not consumed and causes long and large wave tail of applied voltage pulse. The wave tail can accelerate occurrence of spark discharges which are inefficient for discharge-chemical reaction. A control of the pulse wave tail on the reactor was investigated by using a winding resistor. Ozone concentration of 14-mm reactor became higher than 17-mm reactor. The effect of applied voltage between reactor electrodes was investigated by changing of charging voltage. Ozone concentration of 14-mm reactor was even or higher than 17-mm reactor. Additionally, the influence of mixed gas including nitrogen gas was investigated. Ozone concentration of 14-mm reactor increased with increase of nitrogen gas ratio from 0 % to 6%. Although spark discharge was prevented, ozone concentration was not sufficiently improved at all experiment.