CN-122006463-A - Device and method for reducing ammonia slip rate of SCR denitration system

CN122006463ACN 122006463 ACN122006463 ACN 122006463ACN-122006463-A

Abstract

The embodiment of the disclosure provides a device and a method for reducing ammonia slip rate of an SCR denitration system, wherein the device comprises a hearth, an SCR catalytic reactor, an ammonia slip recycling unit, a denitration agent injection unit and a denitration agent injection unit, wherein the SCR catalytic reactor is arranged in a flue at the downstream of the hearth, the ammonia slip recycling unit is communicated with the downstream flue of the SCR catalytic reactor through a smoke pipe, the denitration agent injection unit is arranged at the smoke pipe at the downstream of the ammonia slip recycling unit, the ammonia slip recycling unit is configured to extract smoke at the outlet of the SCR catalytic reactor and convey the extracted smoke to the denitration agent injection unit as carrier wind, and the denitration agent injection unit injects denitration agent into the hearth through carrier wind.

Inventors

ZHANG SEN
XU ZHAOZHAO
WANG LIN
ZHAO HUI

Assignees

新疆能源(集团)和田能源有限责任公司

Dates

Publication Date: 20260512
Application Date: 20260108

Claims (10)

1. A device for reducing ammonia slip rate of an SCR denitration system, comprising: A furnace; The SCR catalytic reactor is arranged in a flue at the downstream of the hearth; An ammonia slip recirculation unit in communication with a downstream flue of the SCR catalytic reactor through a smoke tube; The denitration agent injection unit is arranged on the smoke pipe at the downstream of the ammonia escape recirculation unit; the ammonia escape recycling unit is configured to extract flue gas at the outlet of the SCR catalytic reactor, the extracted flue gas is used as carrier wind to be conveyed to the denitration agent injection unit, and the denitration agent injection unit injects denitration agent into the hearth through the carrier wind.
2. The device for reducing ammonia slip rate of an SCR denitration system according to claim 1, wherein the ammonia slip recycling unit comprises a smoke taking port which is arranged on an outlet flue of the SCR catalytic reactor and is communicated with a smoke pipe, and a high-temperature flue gas conveying fan which is arranged on the smoke pipe, and an outlet of the high-temperature flue gas conveying fan is communicated with the denitration agent spraying unit.
3. The apparatus for reducing ammonia slip rate in an SCR denitration system according to claim 2, wherein said ammonia slip recirculation unit further comprises a dust remover disposed in said flue pipe and disposed upstream of said high temperature flue gas delivery fan.
4. The apparatus for reducing ammonia slip rate of SCR denitration system according to claim 1, wherein said denitration agent injection unit comprises a denitration agent supply assembly provided to said flue pipe and adapted to supply a denitration agent, and a denitration agent injection assembly communicating with said flue pipe and inserted into a flue of said furnace.
5. The apparatus for reducing ammonia slip rate in an SCR denitration system according to claim 4, wherein said denitration agent supply assembly comprises a denitration agent storage bin, a blanking pipe communicated with a discharge port of said denitration agent storage bin, a screw feeder communicated with said blanking pipe, and a venturi aspirator communicated between said screw feeder and said smoke pipe.
6. The apparatus for reducing ammonia slip rate in an SCR denitration system according to claim 4, wherein said denitration agent injection assembly comprises a lance inserted into a flue of a furnace upstream of said SCR catalytic reactor, and a lance shut-off valve provided at an inlet flue pipe of said lance.
7. The apparatus for reducing ammonia slip rate in an SCR denitration system as defined in claim 6, wherein said denitration agent injection assembly comprises a plurality of said spray guns, and a spray gun stop valve corresponding to an inlet flue pipe provided to each of said spray guns.
8. The apparatus for reducing ammonia slip rate in an SCR denitration system according to claim 4, wherein said denitration agent injection unit further comprises a discharge valve provided in a smoke pipe between said denitration agent supply unit and said denitration agent injection unit.
9. The apparatus for reducing ammonia slip rate in an SCR denitration system according to claim 6, further comprising a screen superheater disposed in a flue of the furnace and disposed above the lance.
10. A method of reducing ammonia slip rate in an SCR denitration system, the method being implemented by the apparatus of any one of claims 1 to 9, comprising: extracting flue gas at an outlet of the SCR catalytic reactor; taking the extracted flue gas as carrier wind, mixing the carrier wind with a denitration agent, and then injecting the mixed flue gas into a flue of a hearth for carrying out high Wen Tuoxiao reaction; and (3) enabling the flue gas subjected to the high-temperature denitration reaction to enter the SCR catalytic reactor and perform the low-temperature denitration reaction.

Description

Device and method for reducing ammonia slip rate of SCR denitration system Technical Field The embodiment of the disclosure belongs to the technical field of denitration equipment, and particularly relates to a device and a method for reducing ammonia slip rate of an SCR denitration system. Background The large-scale power station boiler mostly adopts SCR (SELECTIVE CATALYTIC Reduction, selective catalytic Reduction denitration technology), which is one of the flue gas denitration methods with the widest application and highest efficiency at present, and is characterized in that under the action of a catalyst, ammonia (NH 3) is used as a reducing agent to selectively reduce nitrogen oxides (NO x) in flue gas into harmless nitrogen and water vapor, and the denitration efficiency can reach more than 80% -90%. In actual production, since the boiler load rises and falls in real time along with the power grid demand, the flue gas amount and the NOx content therein will fluctuate, and in order to avoid exceeding the flue gas NOx concentration, the unit operator usually adopts an "excessive ammonia injection" mode to control the NOx at a relatively low level (national standard requires NOx concentration <50 mg/m 3, and actual control is usually performed at 40 mg/m 3 or even under 35 mg/m 3 to cope with the fluctuation). The excessive ammonia injection can cause the following hazards of (1) increasing the consumption of the denitration agent and increasing the running cost of the system, and (2) having high ammonia escape rate of the denitration outlet, easily causing ammonium salt aggregation at the air preheater and the low-temperature economizer, causing serious ash accumulation and blockage and affecting the running of equipment. Therefore, how to solve the above-mentioned problems is a technical problem to be solved by those skilled in the art. Disclosure of Invention The embodiment of the disclosure aims at least solving one of the technical problems existing in the prior art and provides a device and a method for reducing ammonia slip rate of an SCR denitration system. In a first aspect of embodiments of the present disclosure, there is provided an apparatus for reducing ammonia slip rate of an SCR denitration system, comprising: A furnace; The SCR catalytic reactor is arranged in a flue at the downstream of the hearth; An ammonia slip recirculation unit in communication with a downstream flue of the SCR catalytic reactor through a smoke tube; The denitration agent injection unit is arranged on the smoke pipe at the downstream of the ammonia escape recirculation unit; the ammonia escape recycling unit is configured to extract flue gas at the outlet of the SCR catalytic reactor, the extracted flue gas is used as carrier wind to be conveyed to the denitration agent injection unit, and the denitration agent injection unit injects denitration agent into the hearth through the carrier wind. Optionally, the ammonia escape recirculation unit comprises a smoke taking port which is arranged on an outlet flue of the SCR catalytic reactor and communicated with the smoke pipe, and a high-temperature flue gas conveying fan which is arranged on the smoke pipe, wherein an outlet of the high-temperature flue gas conveying fan is communicated with the denitration agent injection unit. Optionally, the ammonia escape recirculation unit further comprises a dust remover arranged on the smoke tube and arranged on the upstream of the high-temperature flue gas conveying fan. Optionally, the denitration agent injection unit comprises a denitration agent supply assembly which is arranged on the smoke tube and used for supplying denitration agent, and a denitration agent injection assembly which is communicated with the smoke tube and inserted into a flue of the hearth. Optionally, the denitration agent supply assembly includes denitration agent feed bin, with the unloading pipe of denitration agent feed bin's discharge gate intercommunication, with the screw feeder of unloading pipe intercommunication, and communicate in screw feeder with venturi inhale glassware between the tobacco pipe. Optionally, the denitration agent injection assembly comprises a spray gun inserted into a flue of a furnace chamber at the upstream of the SCR catalytic reactor, and a spray gun stop valve arranged at an inlet smoke tube of the spray gun. Optionally, the denitration agent injection assembly comprises a plurality of spray guns and spray gun stop valves corresponding to inlet smoke pipes of the spray guns. Optionally, the denitration agent injection unit further comprises a discharge valve arranged between the denitration agent supply assembly and the denitration agent injection assembly. Optionally, the device further comprises a screen type superheater arranged in a flue of the hearth and above the spray gun. In a second aspect of the embodiments of the present disclosure, a method for reducing ammonia slip rate of an SCR denitration system is pro