NO_x removal by non-thermal plasma reduction: experimental and theoretical investigations

Abstract

Green and efficient {\mathrm{N}\mathrm{O}}_x removal at low temperature is still desired. {\mathrm{N}\mathrm{O}}_x removal via non-thermal plasma (NTP) reduction is one of such technique. This work presents the experimental and theoretical study on the {\mathrm{N}\mathrm{O}}_x removal via NTP reduction (NTPRD) in dielectric barrier discharge reactor (DBD). The effect of {\mathrm{O}}_2 molar fraction on {\mathrm{N}\mathrm{O}}_x species in the outlet of DBD, and effects of {\mathrm{N}\mathrm{H}}_3/NO molar ratio and discharge power of DBD on {\mathrm{N}\mathrm{O}}_x removal efficiency are investigated. Results indicate that anaerobic condition and higher discharge power is beneficial to direct removal of {\mathrm{N}\mathrm{O}}_x, and the {\mathrm{N}\mathrm{O}}_x removal efficiency can be up to 98.5% under the optimal operating conditions. It is also found that adding {\mathrm{N}\mathrm{H}}_3 is favorable for the reduction of {\mathrm{N}\mathrm{O}}_x to {\mathrm{N}}_2 at lower discharge power. In addition, the {\mathrm{N}\mathrm{O}}_x removal mechanism and energy consumption analysis for the NTPRD process are also studied. It is found that the reduced active species ( {\mathrm{N}}^{\ast }, {\mathrm{N}}^{-}, N⁺, {{\mathrm{N}}_2}^{\ast }, {{\mathrm{N}\mathrm{H}}_2}^{+}, etc.) generated in the NTPRD process play important roles for the reduction of {\mathrm{N}\mathrm{O}}_x to {\mathrm{N}}_2. Our work paves a novel pathway for {\mathrm{N}\mathrm{O}}_x removal from anaerobic gas in industrial application.

Graphical abstract

Keywords

_x removal / NTP reduction / mechanism / energy consumption

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Higher Education Press