System used in cinerator for reducing NOx

Abstract

The invention provides a system to be used in a cinerator for reducing nitrogen oxide, including a cylindrical catalyst-reaction tower (1) having both an inlet (1A) through which exhaust gas exhausted out of the cinerator is introduced therein, and an outlet (1B), the catalyst-reaction tower (1) being divided inside thereof into a mixture-dispersion area (1C), and a catalyst layer area (1D), a nozzle unit (2) through which aqueous ammonia is atomized into the catalyst-reaction tower (1), first and second area-contractors (21, 22) arranged in the mixture-dispersion area (1C), each of the area-contractors (21, 22) having at least one opening (21a, 22a), the opeing (21a) of the first area-contractor (21) being located in no coincidence with the opening (22a) of the second area-contractor (22), and a catalyst (23) included in the catalyst layer area (1D).

Description

technical field [0001] The present invention relates to a system for reducing nitrogen oxides (NOx) in exhaust gas discharged from an incinerator. Background technique [0002] As a method of removing nitrogen oxides (NOx) in the exhaust gas of various incinerators, it is popular to add ammonia (NH 3 ) spray and pass through the catalyst layer, thereby decomposing NOx into nitrogen (N) and water (H 2 O) method. [0003] The denitration reaction of nitrogen oxides in the exhaust gas is represented by the following formula (1) or formula (2). [0004] 4NO+4NH 3 +O 2 →4N 2 +6H 2 O formula (1) [0005] 2NO 2 +4NH 3 +O 2 →3N 2 +6H 2 O formula (2) [0006] Since most of the NOx in the exhaust gas is NO, according to formula (1), NO and NH 3 The molar ratio of ammonia is 1:1, and the amount of ammonia required for the reaction is roughly the same molar amount as that of NOx. [0007] Used in environmental protection equipment, the system that uses catalysts and ammon...

AI Technical Summary

Problems solved by technology

[0009] (1) It is difficult to quickly reach the temperature of the catalyst that can react with ammonia

[0010] (2) Since the amount of exhaust gas is small, it is difficult to uniformly introduce exhaust gas into the catalyst after spraying ammonia, so the concentration distribution of ammonia introduced into the catalyst is not uniform, and as a result, unreacted ammonia tends to leak

[0011] (3) Although the amount of gas to be processed is small, the amount of exhaust gas fluctuates greatly due to individual differences in incineration, making it difficult to control the amount of spray

Therefore, in the method of uniform spraying or the method of controlling the spraying amount by a timer, the occurrence of ammonia leakage caused by unreacted ammonia is unavoidable.

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