A SCR flue gas denitrification pre-dust removal device

Abstract

The invention relates to the field of flue gas dust removal, in particular to an SCR flue gas denitration dust pre-removing device. The SCR flue gas denitration dust pre-removing device is characterized by comprising a front dust hopper, a first horizontal flue, an uptake flue, a second horizontal flue and an SCR reactor, which are sequentially connected, wherein a dust retaining flow guide plate is arranged at an air outlet of the front dust hopper; a dust baffle plate is arranged on the inner wall of a pipeline at the bottom of an inlet of the first horizontal flue; an ammonia spraying grid is mounted in the uptake flue; an air uniformizing plate is arranged at the position, close to an air inlet, in the SCR reactor; a denitration catalyst is arranged below the air uniformizing plate. The SCR flue gas denitration dust pre-removing device is simple in structure, low in pressure loss and high in dust removal efficiency; the dust retaining flow guide plate and the dust baffle plate are arranged, so that larger dust can fall into the dust hopper and be discharged outside, influence on the flowing stability of flue gas of a unit is eliminated, the catalyst is prevented from being blocked by accumulated dust, and the service life of the catalyst is prolonged.

Description

technical field [0001] The invention relates to the field of flue gas dedusting, in particular to an SCR flue gas denitrification pre-dust removal device. Background technique [0002] The SCR reactor is arranged between the boiler economizer and the air preheater. The flue gas has not been dedusted. Due to the relatively large dust concentration in the flue gas, it is easy to cause catalyst wear and poisoning, which shortens the service life of the catalyst. On the other hand, the reaction The lower elbow of the flue inlet section of the flue gas is easy to accumulate dust, which hinders the flue gas flow. When the dust accumulation is serious, it may even cause the shutdown of the furnace and cause huge losses. In order to solve the above problems, some researches have been carried out on the SCR flue gas pre-dust removal device in China. [0003] Chinese patent CN2012105355078 discloses a soot cleaning device in an SCR flue gas denitrification system. By expanding the siz...

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Problems solved by technology

[0002] The SCR reactor is arranged between the boiler economizer and the air preheater. The flue gas has not been dedusted. Due to the relatively large dust concentration in the flue gas, it is easy to cause catalyst wear and poisoning, which shortens the service life of the catalyst. On the other hand, the reaction The lower elbow of the flue inlet section of the flue gas is easy to accumulate dust, which hinders the flow of flue gas. When the dust accumulation is serious, it may even cause the shutdown of the furnace and cause huge losses. In order to solve the above problems, some researches have been carried out on the SCR flue gas pre-dust removal device in China.

[0003] Chinese patent CN2012105355078 discloses a soot cleaning device in an SCR flue gas denitrification system. By expanding the size of the ash hopper and the horizontal flue, and setting the ash baffle and the soot blowing pipe in the horizontal flue, it can remove part of the ash accumulation and reduce the impact of fly ash on the catalyst. However, the dust removal efficiency is relatively low. Enlarging the ash hopper and the horizontal flue will increase the investment and floor area. The size of the horizontal flue will expand, which will easily cause dust to deposit in the flue and cause the flue to block. Set up a soot blowing pipe, and blowing air into the horizontal pipe will easily cause the temperature of the flue gas to drop, resulting in low-temperature poisoning of the catalyst

Chinese patent CN2011101163534 discloses a flue gas denitrification device for preventing popcorn ash from clogging the catalyst. An ash hopper is installed at the lower elbow of the reactor inlet section, and a metal mesh is installed at the vertical section of the flue to remove ash. The device can remove some large particles of ash, However, to achieve a high dust removal efficiency, a large pressure loss is required, which will increase power consumption and operating costs, and if the wire mesh is not cleaned regularly, it will easily cause blockage, making the denitrification system unable to operate stably

In some processes, some dust collectors and ash hoppers with complex structures are added to the flue, resulting in large pressure loss in the system, affecting the stability of flue gas flow, and the investment cost is relatively high

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