Ozone Production in Coaxial DBD Using an Amplitude-Modulated AC Power Supply in Air

ABSTRACT

In this study, a traditional tubular reactor and an amplitude-modulated AC power supply are employed to develop a unique practical ozone generator with a widely adjustable ozone concentration and simultaneously a constant ozone yield. The amplitude-modulated AC high-voltage waveform driving the discharge consists of the T_ON (burst of four consecutive AC cycles) and T_OFF periods. The characteristics of the ozone generation in air were experimentally investigated at different energy densities, duty cycles and air flow rates, as well as cooling conditions and frequencies. The experimental results show that a unique ozone generator has an almost constant ozone yield of 51.68 ± 2.97 g/kWh in the energy density range of 50–350 kJ/m³, while a wide range of ozone concentration and output can be developed through changing the applied voltage amplitude. A higher ozone yield of can be achieved by decreasing the duty cycle and increasing gas flow rate, while higher ozone concentration can be easily achieved by changing air flow rate. The maximum ozone yield of 92 g/kWh is achieved. In contrast to only a single AC cycle in one complete T_ON period, changing duty cycle for a consecutive AC cycles in one complete T_ON period cannot be employed to develop a unique ozone generator with a widely adjustable ozone concentration and simultaneously a constant ozone yield because of different Lissajous figures, discharge energies, positive peaks, negative peaks and their differences for each AC cycle. In addition, the total capacitance of the reactor is not only independent of energy density, duty cycle and cooling condition, but also of AC frequency. A higher AC frequency of the applied high-voltage waveforms leads to a lower dielectric capacitance while increasing gap capacitance.

KEYWORDS:

• Ozone generation
• amplitude-modulated AC power supply
• duty cycle
• adjustable ozone concentration
• constant ozone yield
• air

Additional information

Funding

This work was supported by the Czech Science Foundation under Grant [GA15-04023S]; National Natural Science Foundation of China under Grant [51867018 and 51711530316]; and Natural Science Foundation for Distinguished Young Scholars of Jiangxi Province, China under Grant [2018ACB21011]. L. S. Wei would like to thank the NSFC-CAS agreement for funding his stay at IPP Prague.