Gas cleaning with semi-wet type plasma reactor

An experimental study on the removal of NH₃, NO, and NO _x in concentrations of 10-40 ppm in air has been carried out using plasma chemical reaction in a streamer corona discharge. The results of the performance of dry-type and semi-wet-type reactors are compared. The effect of different types of applied voltages such as rectangular pulse, 60 Hz sinusoidal, and 18 kHz alternating voltages is investigated. During NO removal, O₃ and NO₂ are produced. NO₂ can, partially, be removed with higher power input into the discharge. Another undesirable pollutant, namely N₂ O, is also produced, especially in the case of dry reactors having long residence time (~2.4 s). N₂O production decreases, essentially, to zero at 0.6 s residence time when using a semiwet reactor. In general, higher removal efficiency has been obtained with pulse voltage in a wet reactor. NH₃ in air appears to produce ozone and ammonium nitrate in a discharge. The performance of semiwet reactors with regard to the removal of submicron dust particles has also been investigated and very high removal efficiency (~93% at 0.6 s residence time) has been obtained