Process for reducing an eliminating nitrogen oxides in an exhaust gas

摘要

The concentrations of NO and NO2 in nitrogen oxides contained in an exhaust gas are adjusted to substantially equal mol concentrations, whereupon the exhaust gas is held in contact with a metallic oxide catalyst together with ammonia. Owing to the adjustment of the NO and NO2 concentrations in the nitrogen oxides, the reaction rate is enhanced, and the nitrogen oxides are reduced even at a low temperature. The adjustment of the concentrations of NO and NO2 in the nitrogen oxides is done by the oxidation of NO with ozone, the catalytic oxidation of NO with air or oxygen, the addition of nitric acid, the addition of NO or NO2, etc.