SCR (Selective Catalytic Reduction) flue gas denitration system for burning lignite

Abstract

The invention discloses an SCR (Selective Catalytic Reduction) flue gas denitration system for burning lignite. After flue gas exhausted from a hearth passes through a horizontal flue, an economizer and a high-temperature air preheater and then is fully mixed with reductive ammonia water injected into an ammonia injection grid, the flue gas enters an SCR reactor and generates selective catalytic reduction reaction under the action of a catalyst, and the flue gas enters a low-temperature air preheater after reaction. During lignite burning, the flow of air in an air by-pass pipeline is regulated, so that high-temperature flue gas entering the SCR reactor can be cooled by air conveying to the hearth from a fan in the high-temperature air preheater to 320-400 DEG C needed by a denitration catalyst, and the denitration catalyst does not have a sintering risk at present. After the air supplied by the fan to the hearth is preheated through the low-temperature air preheater, the air is heated by the high-temperature flue gas in the high-temperature air preheater to the temperature range of over 400 DEG C needed by the lignite or lignite co-combustion.

Description

technical field [0001] The invention relates to a post-boiler SCR flue gas denitrification system for lignite or lignite blended combustion, specifically, to a two-stage air preheater using low temperature and high temperature, and the SCR reactor is arranged in the two-stage air preheater Between, to ensure that when lignite is burned, the flue gas temperature in the SCR reactor meets the reaction activity temperature of the denitrification catalyst, and the SCR flue gas denitrification system that avoids the risk of sintering of the denitrification catalyst. Background technique [0002] Traditional flue gas removal systems such as figure 2 : Pulverized coal burns in the furnace 1 to generate high-temperature flue gas, and the high-temperature flue gas passes through the horizontal flue 2 and the economizer 3 in turn; the SCR reactor 8 is connected to the economizer 3 through the flue gas inlet pipe 4, and the flue gas is connected to the The deflector 5, the ammonia inje...

AI Technical Summary

Problems solved by technology

Such a high flue gas temperature is not suitable for denitrification catalysts, and usually results in sintering of denitrification catalysts, resulting in partial or complete loss of activity of denitrification catalysts. Therefore, SCR flue gas denitrification is carried out in boilers that burn lignite or lignite. If the traditional SCR denitrification process is used, Arrange the SCR catalyst between the economizer and the air preheater, the denitrification catalyst has a high risk of sintering

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