Numerical analysis of effects of electric field and pulse duration on discharge DeNoX performance

By virtue of its comparatively high denitrification (deNOx) efficiency and its compactness, the pulsed-discharge deNOx process is considered to be one of the deNOx processes suitable for combustion gas. However, there has been insufficient clear guidance on the optimum electric field, pulse duration, and pulse repetition frequency, and no clear understanding of pulsed-discharge deNOx process. In this study, we have simulated the pulsed-discharge deNOx process by solving the Boltzmann equation for discharge electrons and the deNOx chemical reaction equations simultaneously, and we have shown the time change of chemical species concentration, extracting the main deNOx reactions. The simulation shows that the pulsed-discharge deNOx process consists of two processes, the reduction of NO to N₂ by N radicals and the oxidation of NO to HNO₃ and HNO₂ by OH and O radicals, and that the amounts of radicals produced and consumed are governed by parameters such as the electric field, pulse duration, and pulse repetition frequency. In our simulation, such parameters are varied widely to examine their quantitative effect on the deNOx energy consumption, NxOy removal efficiency, and reduction ratio in the discharge deNOx process. The preliminary pulsed-discharge deNOx performance is estimated from our simulation, indicating that the discharge deNOx process has almost the same performance as the electron-beam deNOx process.