Atomization ejection device and method for SNCR (Selective Non Catalytic Reduction) denitration

Abstract

The invention discloses an atomization ejection device and an atomization ejection method for SNCR (Selective Non Catalytic Reduction) denitration. An ejection gun is placed in a high-temperature furnace flue, the ambient temperature of the ejection gun is determined by a temperature measuring device, when the flue gas temperature is between 850 DEG C and 1,100 DEG C, a starting signal is fed back to a PID (Piping and Instruments Diagram) control module through the temperature measuring device, a protective cover ejection hole is overlapped with a solution tube ejection opening, and an ejection channel is smooth; a urea solution in a liquid storage tank enters a solution tube, the ejection gun is cooled down through the urea solution, a high-pressure gas enters a high-pressure gas tube through a gas inlet and is mixed with the urea solution through a gas ejection opening, and the urea solution is ejected out through the solution tube ejection opening and the protective cover ejection hole; when the fume is deviated from the temperature range of 850-1,100 DEG C, a closure signal is fed back to the PID control module through the temperature measuring device, a hole-free area at the protective cover ejection opening end is overlapped with the solution tube ejection opening, and the ejection channel is closed up so as to prevent grains in the fume from entering the ejection opening; cooling water in a cooling water tank passes through a cooling water valve, enters the solution tube through a solution inlet, and is discharged from a solution outlet so as to ensure that the ejection gun is prevented from high-temperature damage. The atomization ejection device and the atomization ejection method are low in denitration cost, high in efficiency and safe.

Description

technical field [0001] The invention relates to a device and method for removing nitrogen oxides from boiler flue gas, in particular to an atomizing injection device and method for SNCR denitrification, and is especially suitable for circulating fluidized bed boilers. Background technique [0002] The SNCR (selective non-catalytic reduction) denitrification process is to spray the reducing agent solution such as ammonia gas, urea dilute solution, etc. into the area where the temperature of the furnace is 850-1100 ° C, and the reducing agent solution is rapidly thermally decomposed into NH 3 And with the NO in the flue gas x react to form N 2 and H 2 O. The method takes the furnace as the reactor and can be realized by reforming the boiler. [0003] The main reaction formula with ammonia as reducing agent is: [0004] NH 3 +NO x →N 2 +H 2 O; [0005] And the main chemical reaction that adopts urea as reducing agent is: (NH 4 )2CO→2NH 2 +CO NH 2 +NO→N 2 +H 2 O...

AI Technical Summary

Problems solved by technology

However, the temperature field in the furnace is affected by many factors, such as the coal type, the ratio of primary and secondary air, and even the circulation rate, which will affect the temperature field in the furnace.

Changes in the temperature field may cause the location of some spray guns to deviate from the "temperature window" range

At this time, if the spray gun still sprays reducing agent into the furnace, it will seriously affect the denitrification efficiency

[0007] In addition, after some spray guns stop spraying, due to the large amount of dust in the boiler, they are prone to clogging, especially in the positive pressure state of the circulating fluidized bed boiler, which is more prone to nozzle clogging

The clogging of the nozzle will reduce the atomization quality and affect the mixing effect of reducing agent and flue gas, thus reducing the denitrification efficiency

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