Plasma-Assisted Removal of NO from Gas Streams via Ammonia Injection

ABSTRACT

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 NH_i 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 O₂ 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 NH_i radicals.

Key words:

Plasma; dielectric barrier discharge; NO _x removal; selective reduction; NH₃ injection