GB1464050A - Process for removing nitrogen oxides from combustion waste gas - Google Patents

Abstract

1464050 Removing NO x from waste gas IDEMITSU KOSAN CO Ltd 27 Nov 1974 [30 Nov 1973 14 Feb 1974 27 May 1974 30 May 1974] 51501/74 Heading C1A NO x are removed from waste gases by passing the gases through an aqueous dispersion containing a reaction product of an inorganic ferrous salt with an unsubstituted acyclic, aromatic or heterocyclic amine, alkanolamine or ammonia. The ferrous salt may be the sulphate, chloride or nitrate and the molar ratio of the nitrogen-containing compound to the salt is suitably 1 : 1 to 10 : 10, preferably less than 25 : 1. Suitable N-containing compounds are methylamine, ethylamine, propylamine, isopropylamine, n-butylamine, diethylamine, methylethylamine, trimethylamine, triethylamine, aniline, piperidine, morpholine, pyridine, ethanolamine, diethanolamine, triethanolamine, propanolamine, dipropanolamine, ethylmonoethanolamine, n-butylmonoethanolamine, dimethylethanolamine, diethylethanolamine, ethyldiethanolamine and N-butyl diethanolamine. The ferrous salt is preferably present in the aqueous dispersion in a concentration of 0À1 to 30% and the N-containing component at any concentration above 0À1%. The activity of the absorbing agent may be maintained or revived by the addition of SO 2 or its aqueous solution, or an aqueous solution or suspension of a sulphite or bisulphite of a group IA or IIA metal. When SO 2 is present in the waste gas, the presence of a carbonate, bicarbonate, hydroxide or oxide of a group IA or IIA metal is also effective in prolonging the operation of the absorbing agent.