Embedded SCR + SNCR flue gas denitration device and method for grate rotary kiln

Abstract

The invention discloses an embedded SCR + SNCR flue gas denitration device and method for a grate rotary kiln, and belongs to the technical field of sintering and pelletizing flue gas denitration. According to the SCR denitration method, the denitration efficiency is guaranteed, and a flue gas heating system does not need to be arranged. According to a main source of NOX in flue gas discharged by a chain grate-rotary kiln, an SNCR denitration system is arranged at a preheating section II for primary denitration by combining a principle of a pellet air flow system; an SCR denitration device is arranged between a multi-pipe dust remover and a backheating fan in a pelletizing process air flow system and is used for secondary fine denitration. The flue gas with NOx removed returns to an air draft drying section of the chain grate through the heat return fan, production requirements can be met, denitration treatment on the pellet flue gas can be achieved, and compared with an existing most commonly-adopted after-main-exhaust full-flue-gas denitration system, the flue gas does not need to be subjected to heat compensation, and the operation cost can be reduced by about 3 / 4.

Description

technical field [0001] The invention relates to a grate-rotary kiln embedded SCR+SNCR flue gas denitrification device and method, belonging to the technical field of sintering and pelletizing flue gas denitrification. Background technique [0002] NO in the waste gas discharged from the main exhaust system of pellet production X The concentration reaches 250~500mg / Nm 3 , and the oxygen content is as high as 17% to 19%, and the latest ultra-low emission standards require NO X Emission concentration≤50mg / Nm 3 , and the emission concentration should be converted into a benchmark oxygen content of 16%, and the actual denitrification efficiency is required to reach more than 85%. In the traditional flue gas denitrification method, the denitrification efficiency of SNCR is generally 20% to 40%, and the denitrification efficiency of activated carbon method is generally 30% to 60%, which is difficult to meet the ultra-low emission requirements. %, become the preferred process me...

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Problems solved by technology

In the traditional flue gas denitrification method, the denitrification efficiency of SNCR is generally 20% to 40%, and the denitrification efficiency of activated carbon method is generally 30% to 60%, which is difficult to meet the ultra-low emission requirements. %, becoming the preferred process method

[0003] At present, the treatment of pellet flue gas mostly adopts the process route of adding SCR denitrification device to the main exhaust system. Since the catalytic reaction temperature range of SCR denitrification process is 260 ° C ~ 400 ° C, and the temperature of pellet main exhaust gas is between 150 ° C ~ 180 ° C Therefore, a flue gas heating system must be equipped, resulting in high operating costs and energy waste

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