Study of nitrogen reaction kinetics in an industrial ozone generator

Summary form only given. Ozone (O₃) is a powerful oxidant that used in a wide array of applications ranging from various industrial chemical synthesis processes to large-scale water treatment. For many years ozone has been generated by means of dielectric barrier discharges (DBD), where a high-energy electric field propagates between two electrodes separated by a dielectric material and a gap containing either pure oxygen or O₂ with N₂ admixtures. Nitrogen has a significant effect on O₃ production as a third body collider. Understanding the reaction kinetics and the role it plays on O₃ generation is of primary importance and the focus of this study.A proprietary DBD industrial O3 generator was modified for spectroscopic collection of light emission from the plasma discharges. The light was channeled via fiber optic cable to a UV-Vis spectrometer equipped with an ICCD camera for optical emission spectroscopy (OES) analysis. To analyze the spectra, SpecairTM computational software was used to calculate plasma energies and gas temperatures. To corroborate spectral temperature data calculations, a second identical O3 generator was modified to incorporate a K-type thermocouple to the inner electrode segment and physical temperature measurements were recorded. Additionally, exhaust gas from the O3 generator was channeled into an FTIR spectrometer for production analysis. The N2 second positive (2+) band was chosen as the emission spectral line of choice due to its relatively high intensity compared to excited oxygen species and because it can be used to accurately identify average gas energy distribution and temperature. Initial results suggest close agreement between gas temperatures from both physical measurements and computational spectral analysis. The data also hints at a potential relationship between the plasma energy distribution and the ratio of N2 admixture to the O2 feed gas. As N2 concentration increases, there appears to be a correlating increase in N2 vibrational energies yet a decrease in overall gas temperatures. Further analysis is required to fully define the role of N2 in the chemical kinetics.