Stepped injection device for SNCR denitration system, and denitration system using same

Abstract

The invention discloses a stepped injection device for an SNCR denitration system, and a denitration system using the same. The injection device comprises a plurality of ejection units, the injectionunits are mounted in the inlet horizontal flue of a circulating fluidized bed boiler separator, and the injection units are arranged in a stepped manner along the flowing direction of flue gas; everyinjection unit comprises a sleeve and a spray gun, the sleeve is provided with a plurality of injection holes along the axial direction, the spray gun is arranged in the sleeve, the spray gun is provided with a plurality of nozzles, the spray gun is arranged in parallel with the sleeve, the nozzles correspond to the injection holes one to one along the radial direction and the axial position of the injection unit, the directions of the injection mouths of the nozzles are same to the flow direction of the flue gas, one end of the spray gun is provided with a reducing agent inlet and an atomizedair inlet, and one end of the sleeve is provided with a cooling air port; and the reducing agent is injected into the flue in a multi-point and full-coverage manner through the stepped injection device. Compared with conventional CFB boiler injection devices, the stepped injection device can reduce the resistance of the flue gas in order to fully mix the reducing agent with the flue gas, so the denitration efficiency is increased.

Description

technical field [0001] The invention belongs to the technical field of circulating fluidized bed boiler environmental protection, and in particular relates to a stepped injection device of an SNCR denitrification system and a denitrification system using the device. Background technique [0002] Circulating fluidized bed (CFB) boiler technology is a high-efficiency and low-pollution clean coal power generation technology that has developed rapidly in the past ten years. CFB boilers generally use SNCR to remove NOx in flue gas, and the reaction temperature window is 850-1050 °C. Thanks to the good disturbance effect of the cyclone separator, the SNCR denitrification efficiency of the CFB boiler is greatly improved compared with the pulverized coal boiler, up to about 80%. In recent years, the pressure of environmental protection has been increasing, and higher requirements have been put forward for the SNCR denitrification efficiency of CFB boilers. An important factor affect...

AI Technical Summary

Problems solved by technology

Traditional reductant injection devices are usually arranged on both sides of the separator flue. After the reductant is injected into the flue, it is carried by the high-speed flue gas and diverted. It is difficult to reach the center of the flue, resulting in poor mixing efficiency between the flue gas and the reductant. It is difficult to improve the denitrification efficiency, so a large amount of reducing agent needs to be consumed

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