EFFECT OF OXYGEN ON NO_x REMOVAL IN CORONA DISCHARGE FIELD: NO_x BEHAVIOR WITHOUT A REDUCING AGENT

Abstract

A DeNO_x process using a DC corona discharge was investigated experimentally. A mixture system of N₂/O₂/NO was used as a test gas. The compositions such as NO, NO₂, N₂O and so on were analyzed with Fourier transform infrared spectroscopy and an NO_x meter. It was found that the characteristics of NO removal by corona discharge differed remarkably whether or not oxygen exists in the mixture. In regard to the spectrum of light emission from the corona discharge in N₂ atmosphere or N₂/O₂ mixture, some N₂ bands were detected. N₂ dissociation into atomic N and N₂ radical in the corona discharge field was conjectured. Furthermore, ozone was yielded by the corona discharge in the case of the N₂/O₂ mixture. Ozone gas from an ozonizer was added into the N₂/O₂ mixture without corona discharge to investigate the effect of O₃ on the characteristics of NO_x removal by corona discharge. In the case of the N₂/NO mixture, the process of NO reduction was mainly controlled by N₂ radicals excited by the corona discharge. On the other hand, in the case of the N₂/O₂/NO mixture, NO was oxidized by ozone generated from the corona discharge and converted to NO₂ and N₂O₅.

Keywords:

• NO_x removal
• corona discharge
• DeNO_x
• Ozone