A denitrification system applied in a pulverized coal boiler

Abstract

The invention discloses a denitration system applied to a coal dust boiler and aims to provide a denitration system capable of finishing denitration transformation without changing a coal economizer and an air preheater of the boiler. The denitration system comprises a high temperature flue, the coal economizer, the air preheater, an intensive flue conversion structure and an SCR reactor positioned outside the high temperature flue. The intensive flue conversion structure comprises a conversion flue and an inclined partition plate arranged in the conversion flue, the upper end of the conversion flue is provided with a first conversion flue inlet, the side surface of the conversion flue is provided with a first conversion flue outlet, the side surface of the conversion flue is provided with a second conversion flue inlet, and the lower end of the conversion flue is provided with a second conversion flue outlet; the first conversion flue inlet is connected with the outlet of the coal economizer; the first conversion flue outlet is connected with a smoke inlet of the SCR reactor of which a smoke exhausting port is connected with the second conversion flue inlet; the second conversion flue outlet is connected with the inlet of the air preheater.

Description

technical field [0001] The invention relates to a discharge system of a pulverized coal boiler, in particular to a denitrification system applied in a pulverized coal boiler. Background technique [0002] With the increasing environmental protection requirements, the emission indicators of NOx, S02 and smoke dust in thermal power plants are becoming more and more stringent. The current national standard has high requirements for the emission limit of NOx, and the requirement for ultra-low emission is even less than 50 mg / m3. At present, a large number of power plants that have been built need to undergo denitrification transformation to meet the emission requirements because their emissions do not meet the standards. At present, the most mainstream method is to use the SCR reactor (Selective Catalytic Reduction), which is the selective catalytic reduction technology. [0003] The SCR reactor is mainly composed of an SCR catalytic reactor, an ammonia injection system, an am...

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Problems solved by technology

[0004] At present, most of the pulverized coal boilers that need denitrification transformation do not reserve space for the SCR reactor, so the flue gas needs to be led out between the economizer and the air preheater, and then led back after passing through the SCR reactor; However, there is not enough space between the economizer and the air preheater of most coal-fired boilers to lead out and reintroduce the flue gas, which requires the modification of the upper economizer or the lower air preheater to increase The space between the economizer and the air preheater; whether it is the transformation of the economizer or the air preheater, it will not only affect the original performance of the boiler, but also greatly increase the cost and construction period

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