Ozone Generation Efficiency Using Nanosecond Pulsed Plasma at Above ATM Pressures

Abstract

Ozone affects the performance of plasma-based systems including plasma assisted combustion, treatment of combustion byproducts, and other applications requiring high concentrations of reactive radicals. However, mechanisms for ozone generation at higher pressures need more thorough understanding. Nanosecond pulsed plasma has been shown to produce higher ozone generation efficiencies than most other forms of electrical discharges1,2. In this report, studies of ozone generation efficiencies of 160g/kWh at atmospheric pressure from a 40kV, 5ns rise time pulse source with ~73mJ pulse energy operating at 1Hz are presented. Additionally, ozone generation efficiencies of 82g/kWh and 5g/kWh are obtained at same pulse settings at 2 atm and 3 atm pressure respectively. It is seen that ozone generation decreases rapidly as one goes above atmospheric pressure. The reason is hypothesized to be a combined effect of lower energy dissipation in the plasma at higher pressures and collisional deactivation mechanisms. Streamers propagate with different speeds at different pressures resulting in changes of plasma conductivity and other transport properties. The reactor impedance increases which in turn increases the mismatch between the reactor and source and affects power transfer efficiency at higher pressures.