NO/sub x/ removal by corona discharge in a pipe with nozzle electrode system

To improve the efficiency of NO/sub x/ removal, a pipe electrode with a nozzle was used as a discharge electrode in a parallel-plate-type apparatus. A positive DC high voltage was applied to the discharge electrode. Additional gases, namely, N/sub 2/, O/sub 2/, and NH/sub 3/, were introduced into the discharge space through the ionization region at the tips of nozzles; the main flow was a gas mixture containing NO. To study the effect of additional gas composition, small amounts of Ar or CO/sub 2/ were added to the additional gases. Results show that corona characteristics and modes were significantly affected by the additional gas and, in a region of applied voltage, both NO/sub x/ reduction rate and energy yield of NO/sub x/ removal increased with decreasing corona power. It is concluded that high NO reduction rate and energy yield can be obtained by optimizing the additional gas mixture and its flow rate.<>