METHOD OF PURIFYING SMOKE GASES, CONTAINING NITROGEN OXIDES Russian patent published in 2012 - IPC C01B21/00 

FIELD: chemistry.

SUBSTANCE: urea solution is introduced into hot smoke gases (1) with temperature from 200 to 270°C. Catalyst (3) of denitrification is introduced into smoke gases with urea solution. Time of staying of smoke gases between point of urea introduction and point of establishing contact of said smoke gases with catalyst and/or temperature of smoke gases between these two points are regulated in such a way that reaction (II) of decomposition of isocyanic acid, obtained in decomposition (I) of urea, where (I) NH₂-CO-NH₂ → NH₃ + HNCO and (II) NHCO + H₂O → NH₃ + CO₂ into ammonia is not complete. Present in smoke gases isocyanic acid in presence of catalyst reacts with nitrogen oxides for their reduction to nitrogen state.

EFFECT: method makes it possible to reduce ammonia leaks and catalyst contamination.

2 cl, 2 dwg