Ammonia pre-oxidation SNCR (selective non-catalytic reduction) denitration system and method for circulating fluidized bed boiler

Abstract

The invention discloses an ammonia pre-oxidation SNCR (selective non-catalytic reduction) denitration system and method for a circulating fluidized bed boiler, and relates to the technical field of circulating fluidized bed boiler nitrogen oxide control. The ammonia pre-oxidation SNCR denitration system comprises an H2O2 solution and ammonia water mixed solution preparation system, a pre-oxidation system and a reducing agent injection system; and the pre-oxidation system is provided with an ultrasonic atomization device and an ultraviolet irradiation device, and a mixed solution of an H2O2 solution and ammonia water is irradiated by ultraviolet rays, so that ammonia is pre-oxidized to generate amino free radicals (NH2) which react with NO and have high selectivity. A reducing agent containing amino free radicals is sprayed at an inlet of a horizontal flue of a separator of a circulating fluidized bed boiler to be mixed with flue gas for denitration, so that the problems of low SNCR denitration efficiency and high ammonia escape rate during low-load operation of the circulating fluidized bed boiler are solved, the temperature window of SNCR denitration reaction is widened, and the SNCR denitration theory is enriched.

Description

technical field [0001] The invention relates to the technical field of nitrogen oxide control for circulating fluidized bed boilers, in particular to a low-temperature and high-efficiency SNCR denitrification system for circulating fluidized bed boilers and a denitrification method thereof. Background technique [0002] With the continuous improvement of environmental protection requirements, the emission requirements of coal-fired boiler flue gas pollutants are becoming increasingly stringent, especially the requirements for ultra-low emission of sulfur dioxide, nitrogen oxides and dust. [0003] Current coal-fired boiler flue gas NO X The most commonly used control methods are the selective catalytic reduction (SCR) method and the selective non-catalytic reduction (SNCR) method; the SCR method has high denitrification efficiency, mature technology, and is easy to operate, but it has high requirements for the catalyst, and the operating cost and equipment investment are lar...

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Problems solved by technology

[0007] In order to solve the problems in the prior art, the present invention provides a circulating fluidized bed boiler ammonia pre-oxidation SNCR denitrification system and its method, through the use of ultraviolet radiation The mixture of H2O2 solution and ammonia water can pre-oxidize ammonia to produce highly selective amino radicals (∙NH2 sub>), the reductant containing amino radicals is sprayed at the inlet of the horizontal flue of the circulating fluidized bed boiler separator to solve the problems of low denitrification efficiency and high ammonia escape concentration of circulating fluidized bed boiler low-temperature SNCR

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