Pilot Plant Studies on Nox Removal Via No Ozonation and Absorption

The results of experimental investigations on the removal of NOₓ from gases applying ozone as the oxidizing agent and the absorption of higher nitrogen oxides in the sodium hydroxide solutions are presented. The experiment was conducted using a pilot plant installation with the air flow rate 200 m³/h, being a prototype of a boiler flue gas duct and a FGD scrubber. It was shown that in the range of [NOᵣₑf] = 50 ÷ 250 ppm the mechanism of NO ozonation depends on the molar ratio X = O₃/NOᵣₑf: for X ≤ 1.0 oxidation of NO to NO₂ predominates and NO₂ is poorly absorbed, for X >> 1.0 NO₂ undergoes further oxidation to N2O5, which is efficiently absorbed in the scrubber. The stoichiometric molar ratio of complete conversion of NO into N₂O₠is X = 1.5, in these studies to reach the effectiveness η ≥ 90% the molar ratio X was much higher (2.75).