Reactive absorption of NOx using wet discharge plasma reactor

In this paper, the authors report the results of laboratory experiments on NO_x removal (DeNOx) using a nonthermal plasma process. Studies were conducted on a dry-type plasma reactor and several wet-type reactors to evaluate DeNOx efficiency. The reactor geometry was coaxial with an inner discharge electrode and an outer ground electrode wrapped on an insulating glass tube. Simulated flue gas was used in the experiment. The dry-type reactor performed better with the addition of ammonia and water vapor to the simulated gas. In the wet-type reactors, water and NaOH solution were used as absorbents and DeNOx performance was found to be the same in each case. Also, with water as the absorbent and with its pH value dropping below 3, the performance of the wet-type reactors remained constant. Studies on wet-type reactors, further, suggested that about half of NO removed by the plasma was dissociated into N₂ and O₂ and the rest was absorbed by water. The studies indicate that wet-type reactors performed better than the dry-type reactor in the removal of NO_x