Waste gas nitrogen oxides removal - as ammonium nitrate /nitrite on activated charcoal

摘要

Nitrogen oxides are removed from waste gases, esp. from nitric acid producing plants and nitrate pickling processes, in a simple process using compact apparatus, whereby the gases are mixed with NH3 and passed through a bed of activated charcoal, pref. at a temp. near to the water vapour dew point of the gases. Pref. the temp. used is not more than 30 degrees C (15 degrees C) above the dew point. However, it is pref. to raise this by dosing in water vapour or water, pref. into the region 90-120 degrees C. The nitrogen oxides are removed as NH4NO2 and NH4NO3, the activated charcoal being regenerated, as necessary, by washing in water or steam.