Smoke gas and air pre-mixing and dehumidifying device in smoke gas recirculation

Abstract

The invention discloses a smoke gas and air pre-mixing and dehumidifying device in smoke gas recirculation, aims to solve the technical problems to realize a uniform mixing function and a dehumidifying function of smoke gas and combustion-supporting air and eliminate potential safety hazards during operation in severe winter weather, and belongs to the technical field of boiler decreasing and discharging. The smoke gas and air pre-mixing and dehumidifying device is characterized in that an air inlet of a combustion-supporting air inlet section and an inlet of a smoke gas inlet section are formed in the upper part of the inner wall of a smoke gas mixing chamber; a mixed gas outlet is formed in the lower part of the inner wall of the smoke gas mixing chamber; an inner cavity of the smoke gas mixing chamber is further equipped with a guide device for dividing the inner cavity of the smoke gas mixing chamber into a front part and a rear part; the front cavity is a mixed gas inlet channel, and the rear cavity is a mixed gas outlet channel; a first dewatering hole is formed below a joint of a smoke gas conveying tube and a smoke gas inlet; and a second dewatering hole is formed in the lowest part of the inner cavity of the smoke gas mixing chamber. In work, the combustion-supporting air and the smoke gas are jetted in a crossed manner and are fiercely collided and mixed in the smoke gas mixing chamber, so that the smoke gas is sufficiently mixed and subjected to secondary dehumidifying, and therefore, potential safety hazards when a smoke gas recirculation system operates under cold weather are eliminated.

Description

technical field [0001] The invention relates to a device for reducing NOx emission by a boiler using flue gas recirculation technology, in particular to a premixing and dehumidifying device for part of boiler flue gas and combustion-supporting air, which belongs to the technical field of boiler emission reduction. Background technique [0002] With the increasingly prominent environmental problems, the country's emission limits for boiler air pollutants are becoming more and more stringent. Flue gas recirculation technology, that is, part of the flue gas is mixed with fresh air and sent to combustion equipment and boilers to participate in combustion. Because it can reduce the combustion temperature and oxygen concentration, it can effectively suppress the generation of fuel-type NOx and thermal NOx, effectively It is widely used to reduce the NOx emission concentration of boilers, and it is an effective and cost-effective low-nitrogen combustion method. Taking natural gas ...

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Problems solved by technology

[0003] The traditional flue gas recirculation technology is that the flue gas and combustion air are mixed and sent to the burner for combustion. In most cases, the flue gas is only led from a pipe to the blower inlet, but this method has poor mixing. And the flue gas of the boiler contains gaseous water vapor, especially the fuel gas boiler, which contains about 20% water vapor

In the cold winter, especially in the northern regions, the water vapor in the flue gas will condense to freeze when encountering a large amount of cold air, blocking the air passage or affecting the normal operation of the blower, especially making the fan impeller freeze, affecting its dynamic balance and normal operation. operation, affecting the safe operation of the boiler, and even causing shutdown and boiler deflagration

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