Ozone generation in dry air using pulsed discharges with and without a solid dielectric layer

Energy efficient generation of ozone is very important because ozone is bei ng used increasingly in a wide range of industrial applications. Ozonizers usually use dielectric harrier discharges and employ alternating current (a c) with consequent heat generation, which necessitates cooling. In the pres ent study, very short duration pulsed voltage is employed resulting in redu ced heating of the gas and discharge reactor, A comparison of ozone generat ion in dry air using a coaxial concentric electrode system with and without a solid dielectric layer is reported. Two types of dielectric layers were employed, ceramic and polyvinylchloride (Pvc). The effects of peak pulsed v oltage (12.5 to 62 kV), reactor length (0.1 to 1 m), pulse repetition rate (25 to 400 pulses per second, pps), gas flow rate (1.5 to 3.0 l/min) and va riation of the pitch length of the spiral wire forming the central electrod e (5 to 10 mm) on the concentration and production yield of ozone (g/kWh) a re reported. A comparison is made between the performance of discharge reac tors with (ceramic reactor Type IIC and PVC reactor Type IIP) and without ( reactor Type 1) a dielectric layer, using the same electrode gap separation (15 mm) and reactor lengths (0.157 and 1 m). High production yields of ozo ne in dry air of similar to 122, 52 and 60 g/kWh were obtained when using, respectively ceramic, Pvc, and no dielectric layer, for a fixed pulse rate of 100 pps, 1.5 l/min flow rate and for a relatively short length of the re actor of 157 mm.