CN114768492A - SCR denitration partition system and working method thereof - Google Patents
SCR denitration partition system and working method thereof Download PDFInfo
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- CN114768492A CN114768492A CN202210462406.6A CN202210462406A CN114768492A CN 114768492 A CN114768492 A CN 114768492A CN 202210462406 A CN202210462406 A CN 202210462406A CN 114768492 A CN114768492 A CN 114768492A
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- 238000005192 partition Methods 0.000 title claims abstract description 25
- 238000000034 method Methods 0.000 title claims abstract description 16
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 claims abstract description 73
- 238000002347 injection Methods 0.000 claims abstract description 45
- 239000007924 injection Substances 0.000 claims abstract description 45
- 238000010790 dilution Methods 0.000 claims abstract description 39
- 239000012895 dilution Substances 0.000 claims abstract description 39
- 229910021529 ammonia Inorganic materials 0.000 claims abstract description 35
- 239000003638 chemical reducing agent Substances 0.000 claims abstract description 29
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 claims description 13
- 239000003546 flue gas Substances 0.000 claims description 13
- 238000013316 zoning Methods 0.000 claims description 10
- 239000000243 solution Substances 0.000 claims description 5
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Chemical compound NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 claims description 3
- 239000004202 carbamide Substances 0.000 claims description 3
- 238000005507 spraying Methods 0.000 abstract description 3
- 239000000203 mixture Substances 0.000 description 3
- 238000001514 detection method Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000003068 static effect Effects 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000006479 redox reaction Methods 0.000 description 1
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/30—Controlling by gas-analysis apparatus
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
- B01D53/86—Catalytic processes
- B01D53/8621—Removing nitrogen compounds
- B01D53/8625—Nitrogen oxides
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
- B01D53/86—Catalytic processes
- B01D53/8696—Controlling the catalytic process
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2251/00—Reactants
- B01D2251/20—Reductants
- B01D2251/206—Ammonium compounds
- B01D2251/2062—Ammonia
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2258/00—Sources of waste gases
- B01D2258/02—Other waste gases
- B01D2258/0283—Flue gases
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- Chemical & Material Sciences (AREA)
- Environmental & Geological Engineering (AREA)
- Analytical Chemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Health & Medical Sciences (AREA)
- Biomedical Technology (AREA)
- Treating Waste Gases (AREA)
Abstract
The invention discloses an SCR denitration subarea system and a working method thereof.A same cross section in a denitration inlet flue is divided into N inlet subareas, an ammonia injection grid is uniformly distributed in each inlet subarea, a plurality of outlet subareas are distributed in a denitration outlet flue, and a NOx analyzer is arranged in each outlet subarea; the system comprises an ammonia-air mixing device, a controller, a reducing agent injection device, a dilution fan, an ammonia-air mixing device and a dilution fan, wherein the ammonia-air mixing device corresponds to a reducing agent injection device, an inlet partition and an outlet partition, an outlet of the dilution fan is communicated with an air inlet of each ammonia-air mixing device, an outlet of the reducing agent injection device is communicated with an ammonia inlet of the ammonia-air mixing device, an outlet of the ammonia-air mixing device is communicated with an ammonia spraying grid in the corresponding inlet partition, and the controller is connected with a NOx analyzer, the dilution fan and the reducing agent injection device.
Description
Technical Field
The invention belongs to the field of flue gas treatment, and relates to an SCR denitration zoning system and a working method thereof.
Background
A flue gas SCR denitration system is a facility for treating NOx in flue gas of a current coal-fired power plant, a flue in the conventional SCR system usually adopts a flat and long flue at the outlet of an economizer, an ammonia injection grid and a static mixer are arranged in a vertical flue, a catalyst reactor similar to a cube is arranged at the same time, ammonia is injected into the flue through the ammonia injection grid and is mixed with the flue gas through the static mixer, finally, the NOx and the ammonia are subjected to oxidation-reduction reaction in the square reactor to finally generate N2And H2And (O). The current disadvantages of the method are that:
1) the position that the ammonia of spouting was arranged all is in SCR entry elongated flue, because NOx distributes often can have great deviation because the different exist of different operating mode combustion conditions in the SCR entry elongated flue, and the rule of distribution is also different, cause the ammonia injection volume of present fixed ammonia injection grid can not track NOx's volume in real time and change, lead to ammonia and NOx's mismatching, finally lead to the NOx deviation behind the SCR reactor great, local ammonia escape is great.
2) The conventional zoning technology is that ammonia and air are mixed and then are zoned, the air pressure of mixed gas is low and is usually 1000-2000 Pa, and meanwhile, a zoning adjusting valve adopts a large-diameter butterfly valve, so that on one hand, the adjustment dead zone and linearity of ammonia spraying are poor, and on the other hand, the ammonia spraying adjustment among zones are mutually influenced.
3) The enactment of ultralow emission environmental protection regulation, conventional SCR is more sensitive to the deviation that the entry NOx distributes, leads to local ammonia excessive and escape more easily, and partial region requires NOx export numerical value lower simultaneously, and denitration efficiency is higher, if adopts conventional SCR, threatens the safe and reliable operation of follow-up equipment easily.
Therefore, an SCR denitration zoning system and method need to be designed to realize uniform mixing of all components in flue gas and meet the requirement of flexibility peak shaving of future coal-fired units.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provides an SCR denitration subarea system and a working method thereof, and the system and the working method thereof can realize uniform mixing of all components in flue gas.
In order to achieve the purpose, the SCR denitration zoning system comprises a controller, a denitration inlet flue, a denitration reactor, a denitration outlet flue, a dilution fan, a plurality of reducing agent injection devices and a plurality of ammonia-air mixing devices;
dividing the denitration inlet flue into N inlet subareas according to the same cross section in the denitration inlet flue, wherein an ammonia injection grid is uniformly distributed in each inlet subarea, a plurality of outlet subareas are distributed in the denitration outlet flue, and a NOx analyzer is arranged in each outlet subarea;
the ammonia-air mixing device corresponds to a reducing agent injection device, an inlet partition and an outlet partition, an outlet of the dilution fan is communicated with an air inlet of each ammonia-air mixing device, an outlet of the reducing agent injection device is communicated with an ammonia inlet of the ammonia-air mixing device, an outlet of the ammonia-air mixing device is communicated with an ammonia injection grid in the corresponding inlet partition, and the controller is connected with the NOx analyzer, the dilution fan and the reducing agent injection device.
The ammonia-air mixing device is characterized by further comprising a plurality of dilution air branch pipes, wherein one dilution air branch pipe corresponds to one ammonia-air mixing device, an outlet of the dilution fan is communicated with inlets of the dilution air branch pipes, and an outlet of each dilution air branch pipe is communicated with an air inlet of the corresponding ammonia-air mixing device.
The number N of the inlet partitions is more than or equal to 1.
The working method of the SCR denitration zoning system comprises the following steps:
the method comprises the steps that dilution air output by a dilution fan enters an ammonia-air mixing device, urea solution or ammonia gas output by a reducing agent injection device enters the ammonia-air mixing device, the dilution air is mixed with a reducing agent in the ammonia-air mixing device, then the dilution air enters an ammonia injection grid in a corresponding inlet partition, then the dilution air is injected into the inlet partition through the ammonia injection grid, then the dilution air is mixed with flue gas, then the mixture enters a denitration reactor for denitration, then the mixture enters a denitration outlet flue, the concentration of NOx in the outlet partition is detected through a NOx analyzer, the injection flow of the corresponding reducing agent injection device is adjusted according to the concentration, and the concentration of NOx in each outlet partition is controlled below a target value.
The invention has the following beneficial effects:
when the SCR denitration subarea system and the working method thereof are specifically operated, the thinking of subarea detection and control is adopted, the interiors of a denitration inlet flue and a denitration outlet flue are divided into a plurality of inlet subareas and outlet subareas, the concentration of NOx in the outlet subareas is detected by a NOx analyzer, the amount of reducing agent sprayed in the inlet subareas is controlled according to the concentration, so that subarea control and detection are realized, the concentration of NOx in each outlet subarea is controlled below a target value, so that the uniform mixing of each component in flue gas is realized, and the SCR denitration subarea system and the working method thereof have the advantages of simple structure, convenience in operation and strong practicability.
Drawings
FIG. 1 is a schematic structural diagram of the present invention.
Wherein, 1 is dilution fan, 2 is reductant injection apparatus, 3 is the empty mixing arrangement of ammonia, 4 is denitration inlet flue, 5 is the denitration reactor, 6 is denitration outlet flue, 7 is the NOx analysis appearance.
Detailed Description
In order to make the technical solutions of the present invention better understood, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, not all of the embodiments, and are not intended to limit the scope of the present disclosure. Moreover, in the following description, descriptions of well-known structures and techniques are omitted so as to not unnecessarily obscure the concepts of the present disclosure. All other embodiments, which can be obtained by a person skilled in the art without making any creative effort based on the embodiments in the present invention, shall fall within the protection scope of the present invention.
There is shown in the drawings a schematic block diagram of a disclosed embodiment in accordance with the invention. The figures are not drawn to scale, wherein certain details are exaggerated and some details may be omitted for clarity of presentation. The shapes of various regions, layers and their relative sizes and positional relationships shown in the drawings are merely exemplary, and deviations may occur in practice due to manufacturing tolerances or technical limitations, and a person skilled in the art may additionally design regions/layers having different shapes, sizes, relative positions, according to actual needs.
Referring to fig. 1, the SCR denitration zoning system of the present invention comprises a denitration inlet flue 4, a denitration reactor 5, a denitration outlet flue 6, a dilution fan 1, a plurality of dilution air branch pipes, a plurality of reducing agent injection devices 2, and a plurality of ammonia-air mixing devices 3;
dividing the denitration inlet flue 4 into N inlet subareas according to the same cross section in the denitration inlet flue, wherein the number N of the inlet subareas is more than or equal to 1, ammonia injection grids are uniformly distributed in each inlet subarea, a plurality of outlet subareas are distributed in the denitration outlet flue 6, and a NOx analyzer 7 is arranged in each outlet subarea;
a dilution air branch pipe corresponds to an ammonia-air mixing device 3, a reducing agent injection device 2, an inlet partition and an outlet partition, an outlet of a dilution fan 1 is communicated with inlets of dilution air branch pipes, an outlet of each dilution air branch pipe is communicated with an air inlet of the corresponding ammonia-air mixing device 3, an outlet of the reducing agent injection device 2 is communicated with an ammonia inlet of the ammonia-air mixing device 3, an outlet of the ammonia-air mixing device 3 is communicated with an ammonia injection grid in the corresponding inlet partition, and a controller is connected with a NOx analyzer 7, the dilution fan 1 and the reducing agent injection device 2.
The working method of the SCR denitration zoning system comprises the following steps:
the diluted air output by the dilution fan 1 enters the ammonia-air mixing device 3, the urea solution or ammonia gas output by the reducing agent injection device 2 enters the ammonia-air mixing device 3, in the ammonia-air mixing device 3, the diluted air is mixed with the reducing agent, then the diluted air enters an ammonia injection grid in a corresponding inlet subarea, then the diluted air is injected into the inlet subarea through the ammonia injection grid, then the diluted air is mixed with flue gas, then the diluted air enters the denitration reactor 5 for denitration, then the diluted air enters the denitration outlet flue 6, the concentration of NOx in the outlet subarea is detected through the NOx analyzer 7, the injection flow of the NOx corresponding to the reducing agent injection device 2 is adjusted according to the concentration, and the concentration of the NOx in each outlet subarea is controlled below a target value.
The invention can fully mix the flue gas NOx in the flue gas at the SCR inlet with the reducing agent, and meet the requirement of the correspondence of the front and rear flue gas components of the ammonia injection system.
Example one
Referring to fig. 1, the number of the dilution air branch pipes, the reducing agent injection device 2, the ammonia-air mixing device 3, the inlet partition, and the outlet partition is three.
Claims (4)
1. An SCR denitration zoning system is characterized by comprising a controller, a denitration inlet flue (4), a denitration reactor (5), a denitration outlet flue (6), a dilution fan (1), a plurality of reducing agent injection devices (2) and a plurality of ammonia-air mixing devices (3);
the same cross section in the denitration inlet flue (4) is divided into N inlet subareas, an ammonia injection grid is uniformly distributed in each inlet subarea, a plurality of outlet subareas are distributed in the denitration outlet flue (6), and a NOx analyzer (7) is arranged in each outlet subarea;
an ammonia-air mixing device (3) corresponds to a reducing agent injection device (2), an inlet partition and an outlet partition, an outlet of a dilution fan (1) is communicated with an air inlet of each ammonia-air mixing device (3), an outlet of the reducing agent injection device (2) is communicated with an ammonia inlet of the ammonia-air mixing device (3), an outlet of the ammonia-air mixing device (3) is communicated with an ammonia injection grid in the corresponding inlet partition, and a controller is connected with a NOx analyzer (7), the dilution fan (1) and the reducing agent injection device (2).
2. The SCR denitration zoning system according to claim 1, further comprising a plurality of dilution air branch pipes, wherein one dilution air branch pipe corresponds to one ammonia air mixing device (3), an outlet of the dilution fan (1) is communicated with an inlet of each dilution air branch pipe, and an outlet of each dilution air branch pipe is communicated with an air inlet of the corresponding ammonia air mixing device (3).
3. The SCR denitration zone system of claim 1, wherein the number N of inlet zones is greater than or equal to 1.
4. The method of operating an SCR de-nitrification zoned system of claim 2, comprising the steps of:
the method comprises the steps that dilution air output by a dilution fan (1) enters an ammonia-air mixing device (3), urea solution or ammonia gas output by a reducing agent injection device (2) enters the ammonia-air mixing device (3), the dilution air is mixed with a reducing agent in the ammonia-air mixing device (3), then enters an ammonia injection grid in a corresponding inlet partition, is injected into the inlet partition through the ammonia injection grid, is mixed with flue gas, enters a denitration reactor (5) for denitration, then enters a denitration outlet flue (6), the concentration of NOx in the outlet partition is detected through a NOx analyzer (7), the injection flow of the corresponding reducing agent injection device (2) is adjusted according to the concentration, and the concentration of NOx in each outlet partition is controlled below a target value.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210462406.6A CN114768492A (en) | 2022-04-28 | 2022-04-28 | SCR denitration partition system and working method thereof |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210462406.6A CN114768492A (en) | 2022-04-28 | 2022-04-28 | SCR denitration partition system and working method thereof |
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| CN114768492A true CN114768492A (en) | 2022-07-22 |
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE60020070D1 (en) * | 1999-08-13 | 2005-06-16 | Johnson Matthey Plc | CATALYTIC HATCH FILTER WITH POROUS SEPARATION WALLS |
| CN205627632U (en) * | 2016-05-12 | 2016-10-12 | 西安西热锅炉环保工程有限公司 | High performance SCR minimum discharge control system based on subregion mixes to be adjusted |
| CN106000087A (en) * | 2016-05-12 | 2016-10-12 | 西安西热锅炉环保工程有限公司 | High-performance SCR ultra-low emission control system based on subarea mixed adjustment |
| CN212790506U (en) * | 2020-08-05 | 2021-03-26 | 上海鲁源控制设备有限公司 | Denitration ammonia injection fine adjustment system |
| CN217139893U (en) * | 2022-04-28 | 2022-08-09 | 西安西热锅炉环保工程有限公司 | SCR denitration subregion system |
-
2022
- 2022-04-28 CN CN202210462406.6A patent/CN114768492A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE60020070D1 (en) * | 1999-08-13 | 2005-06-16 | Johnson Matthey Plc | CATALYTIC HATCH FILTER WITH POROUS SEPARATION WALLS |
| CN205627632U (en) * | 2016-05-12 | 2016-10-12 | 西安西热锅炉环保工程有限公司 | High performance SCR minimum discharge control system based on subregion mixes to be adjusted |
| CN106000087A (en) * | 2016-05-12 | 2016-10-12 | 西安西热锅炉环保工程有限公司 | High-performance SCR ultra-low emission control system based on subarea mixed adjustment |
| CN212790506U (en) * | 2020-08-05 | 2021-03-26 | 上海鲁源控制设备有限公司 | Denitration ammonia injection fine adjustment system |
| CN217139893U (en) * | 2022-04-28 | 2022-08-09 | 西安西热锅炉环保工程有限公司 | SCR denitration subregion system |
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