Dielectric barrier discharges for ozone generation

Non-thermal plasma discharges, particularly dielectric barrier discharges (DBDs), are the most common method of ozone generation. The aim of this research was to optimize the micro-discharges in DBDs, to improve ozone generation efficiency. The electrical characteristics of DBDs were researched, and the effects of the physical and electrical parameters of DBDs on ozone generation were investigated. Four DBD based ozone reactors, including plate configuration and cylindrical configuration, were designed and developed. Three major energization modes, including transient (40 ms) AC power supply, continuous AC power supply and pulsed power supply, were used for the investigation of ozone generation performance.Under transient AC energisation in oxygen, it was found that the ozone generation efficiency at 2 bar absolute was 217 g/kWh, increased by 31% compared with that at 1 bar absolute. The ozone generation efficiency was found to increase with decreasing E/N in the range from 126 Td to 185 Td. Under continuous AC energisation, the ozone concentration was found to increase as the gas flow rate decreased (from 1 L/min to 0.4 L/min) or applied voltage was increased (from 3.5 kV to 6 kV). Under optimized conditions, the highest ozone concentration obtained was 271 g/Nm3, which is promising in comparison with previously-published data. The ozone generation efficiency was found to reduce as the ozone concentration increased above 30 g/Nm3. Furthermore, it was found that the AC energization frequency had no obvious effect on the behaviour of micro-discharges, or on the ozone generation efficiency. Pulsed DBDs for ozone generation was found to be less efficient than continuous AC energisation, for the conditions investigated herein.This research has achieved the desired combination of high ozone generation efficiency at high ozone concentration (>150 g/Nm3), based on DBDs. The curve of ozone generation efficiency versus ozone concentration achieved shows more efficient performance than that in the literature: at the typical industrial ozone concentration of 150 g/Nm3 for waste water treatment, the ozone generation efficiency in this work was ~8.2 kWh/kg, ~20% higher than that in the literature.Non-thermal plasma discharges, particularly dielectric barrier discharges (DBDs), are the most common method of ozone generation. The aim of this research was to optimize the micro-discharges in DBDs, to improve ozone generation efficiency. The electrical characteristics of DBDs were researched, and the effects of the physical and electrical parameters of DBDs on ozone generation were investigated. Four DBD based ozone reactors, including plate configuration and cylindrical configuration, were designed and developed. Three major energization modes, including transient (40 ms) AC power supply, continuous AC power supply and pulsed power supply, were used for the investigation of ozone generation performance.Under transient AC energisation in oxygen, it was found that the ozone generation efficiency at 2 bar absolute was 217 g/kWh, increased by 31% compared with that at 1 bar absolute. The ozone generation efficiency was found to increase with decreasing E/N in the range from 126 Td to 185 Td. Under continuous AC energisation, the ozone concentration was found to increase as the gas flow rate decreased (from 1 L/min to 0.4 L/min) or applied voltage was increased (from 3.5 kV to 6 kV). Under optimized conditions, the highest ozone concentration obtained was 271 g/Nm3, which is promising in comparison with previously-published data. The ozone generation efficiency was found to reduce as the ozone concentration increased above 30 g/Nm3. Furthermore, it was found that the AC energization frequency had no obvious effect on the behaviour of micro-discharges, or on the ozone generation efficiency. Pulsed DBDs for ozone generation was found to be less efficient than continuous AC energisation, for the conditions investigated herein.This research has achieved the desired combination of high ozone generation efficiency at high ozone concentration (>150 g/Nm3), based on DBDs. The curve of ozone generation efficiency versus ozone concentration achieved shows more efficient performance than that in the literature: at the typical industrial ozone concentration of 150 g/Nm3 for waste water treatment, the ozone generation efficiency in this work was ~8.2 kWh/kg, ~20% higher than that in the literature