Plasma-assisted removal of NO from gas streams via ammonia injection

Removal of nitric oxide (NO) from gas streams via combined NH3 injection with dielectric barrier discharge (DBD) plasmas was experimentally investigated. Removal of NO was principally achieved via its reaction with NHi radicals generated with DBD plasmas. Removal efficiency of NO was measured as a function of stoichiometric ratio, applied voltage, and inlet NO concentration of the gas stream. Experimental results showed that as much as 80% of NO was removed from gas streams operating at room temperature. Increase in NH3/NO molar ratio and applied voltage enhances NO removal efficiency. NO removal efficiency decreases slightly as oxygen content in the gas stream increases from 0% to 6%, indicating the characteristic of selective reduction in this process. However, 15 ppmv N2O was detected with Fourier transform infrared for gas streams containing 6% by volume O-2 and 300 ppmv NO. Results of this study indicated that conventional SNCR process could be operated at a much lower temperature by applying plasma technology to generate NHi radicals.