CN219272672U - Flow guiding optimization device for denitration of tail flue gas of hearth - Google Patents
Flow guiding optimization device for denitration of tail flue gas of hearth Download PDFInfo
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- CN219272672U CN219272672U CN202222995816.5U CN202222995816U CN219272672U CN 219272672 U CN219272672 U CN 219272672U CN 202222995816 U CN202222995816 U CN 202222995816U CN 219272672 U CN219272672 U CN 219272672U
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- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 title claims abstract description 45
- 239000003546 flue gas Substances 0.000 title claims abstract description 45
- 238000005457 optimization Methods 0.000 title claims abstract description 16
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 claims abstract description 38
- 229910021529 ammonia Inorganic materials 0.000 claims abstract description 21
- 238000002347 injection Methods 0.000 claims abstract description 13
- 239000007924 injection Substances 0.000 claims abstract description 13
- 238000006243 chemical reaction Methods 0.000 claims abstract description 9
- XKMRRTOUMJRJIA-UHFFFAOYSA-N ammonia nh3 Chemical compound N.N XKMRRTOUMJRJIA-UHFFFAOYSA-N 0.000 abstract description 6
- 238000000034 method Methods 0.000 abstract description 5
- 230000009471 action Effects 0.000 abstract description 3
- 230000008569 process Effects 0.000 abstract description 3
- 238000010438 heat treatment Methods 0.000 abstract description 2
- 239000003054 catalyst Substances 0.000 description 9
- 238000005507 spraying Methods 0.000 description 7
- 230000000694 effects Effects 0.000 description 6
- 229910000831 Steel Inorganic materials 0.000 description 3
- 230000004048 modification Effects 0.000 description 3
- 238000012986 modification Methods 0.000 description 3
- 239000010959 steel Substances 0.000 description 3
- 238000005299 abrasion Methods 0.000 description 2
- 238000009826 distribution Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 238000006722 reduction reaction Methods 0.000 description 2
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Chemical compound NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 description 1
- 239000004202 carbamide Substances 0.000 description 1
- 238000010531 catalytic reduction reaction Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000003344 environmental pollutant Substances 0.000 description 1
- 239000010881 fly ash Substances 0.000 description 1
- 230000007062 hydrolysis Effects 0.000 description 1
- 238000006460 hydrolysis reaction Methods 0.000 description 1
- 238000003754 machining Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 231100000719 pollutant Toxicity 0.000 description 1
- 238000010248 power generation Methods 0.000 description 1
- 238000003466 welding Methods 0.000 description 1
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Abstract
The utility model relates to a diversion optimization device for denitration of flue gas at the tail part of a hearth, which comprises an upper elbow guide plate (28), a lower elbow guide plate (29), and a first guide plate (21), a second guide plate (22), a third guide plate (23) and a fourth guide plate (24) which are respectively arranged at the four positions of an inlet of a denitration system, a lower elbow, a lower ammonia injection grid layer and an upper rectifying grid layer; the fourth baffle (24) is arranged behind the upper elbow baffle (28); the second deflector (22) is arranged above the lower elbow deflector (29). The flue gas flows out of the economizer of the tail heating surface of the pi-type boiler, the phenomenon of turbulence and large flow speed deviation in the flowing process is obviously weakened through the rectifying action of the guide plate, the ammonia nitrogen is mixed more fully, the uniformity of the flow field in the ammonia injection area and the reaction tower area is improved through calculation, and the denitration efficiency of the device is improved.
Description
Technical Field
The utility model belongs to the technical field of thermal power generation, and particularly relates to a diversion optimization device for denitration of tail flue gas of a hearth.
Background
With the increasing national requirements on the emission standard of atmospheric NOx, the control requirements of the coal-fired power plant on the pollutant emission are also higher, so that the emission of NOx is ensured to meet the national standard, and a series of problems such as air preheater blockage caused by excessive ammonia injection are prevented. The Selective Catalytic Reduction (SCR) flue gas denitration technology has higher denitration efficiency and is widely applied to a denitration system of a power plant.
An SCR denitration device of a certain power plant adopts a urea hydrolysis method, ammonia-air mixture is sprayed into flue gas through an ammonia spraying grid, and after mixing, reduction reaction is carried out on a catalyst layer of a denitration reaction tower, and NOx is reacted to generate N 2 And H 2 O. Because the operation period is longer, the components of working media in the flue gas are complex, and the phenomena of large flue gas flow velocity deviation, high ammonia nitrogen mole ratio and the like exist in a plurality of areas, the denitration efficiency is seriously influenced. The result of numerical calculation shows that the influence of the non-uniformity of the transverse flow fields of the ammonia injection grid and the catalyst layer area on the mixing of ammonia nitrogen is the greatest, meanwhile, the non-uniform flow also influences the measurement of the concentration of NOx, the measurement is misaligned, the ammonia consumption is improper, and the economy of a unit is damaged.
Referring to fig. 1, the flow guiding device arranged in the original flue only has two groups of flow guiding plates and flow rectifying grids at the upper elbow and the lower elbow, has limited optimizing effect on the flow field, and shows that the flow field after the reducing flue is unevenly distributed, the turbulence and turbulence phenomenon in the vertical flue are serious, and the speed deviation above the catalyst layer is large.
Wherein, the problem of non-uniformity of the original flue arrangement flow field is expressed by the relative deviation coefficient Cv of the upper layer speed of the ammonia injection grid 1 The value is up to 71.6%, and the upper speed deviation coefficient Cv of the rectification grid is as high as 2 The position of the upper half meter of the catalyst reaches 40.2%, and the speed deviation is 32.1%.
After the flue gas of the original flue enters the reducing flue of the inlet section, most of the flue gas is concentrated on the right side of the pipeline, so that the flow velocity of the left side area is small, the transverse flow is easy to generate, and the normal flow of the flue gas before entering the ammonia injection grid is seriously disturbed.
The arrangement position of 4 guide plates of the lower elbow of the original flue is unsuitable, the gap between the guide plate at the lowest layer and the outer wall of the flue is small, the pressure drop is as high as-96 Pa, the pressure drop at the inner sides of the guide plates at the other positions is between-40 Pa and-50 Pa, the high pressure drop not only influences the flue gas guide process, but also is easy to accumulate fly ash after long-time operation so as to cause the flow field to be poor.
Disclosure of Invention
The utility model aims to provide a diversion optimization device for denitration of flue gas at the tail part of a hearth, so as to solve the technical problems.
The utility model provides a diversion optimization device for denitration of flue gas at the tail part of a hearth, which comprises an upper elbow guide plate, a lower elbow guide plate, a first guide plate, a second guide plate, a third guide plate and a fourth guide plate which are respectively arranged at the positions of an inlet of a denitration system, the lower elbow, the lower layer of an ammonia injection grid and the upper layer of the rectification grid; the fourth deflector is arranged behind the upper elbow deflector; the second baffle is disposed above the lower elbow baffle.
Further, the total of nine first guide plates are provided, each first guide plate is composed of a straight guide plate with the same length and an inclined guide plate with different inclination angles, and the first guide plates are used for enabling the flue gas to be uniformly distributed in the reducing flue.
Further, the two second guide plates are arranged above the lower elbow guide plates in parallel, and are used for enabling the flue gas passing through the lower elbow guide plates to incline to the inner side of the flue so as to enable the flue gas entering the straight section to be uniformly distributed in the whole flue.
Further, the total of fourteen third guide plates are vertically arranged at the lower part of the straight-section flue and are filled in the whole straight-section flue.
Further, five fourth guide plates are distributed behind the upper elbow guide plates, wherein the upper two fourth guide plates are parallel to the outer contour of the upper elbow, and are used for enabling the flue gas at the upper layer of the upper elbow to incline to the inner side of the reaction tower after entering the reaction tower; the lower three fourth guide plates keep the streamline of the inlet and the outlet of the upper elbow guide plate horizontal, and the middle bottom guide plates of the lower three fourth guide plates are fold line type guide plates for enabling the streamline on the inner side of the flue to be obliquely injected into the rectification grid.
By means of the scheme, the flow guiding optimization device for denitration of the tail flue gas of the hearth has good effect on the economical efficiency of the lifting system, and specifically comprises the following technical effects:
1. after all the guide plates are arranged, the speed deviation Cv of the upper side of the ammonia injection grid 1 Reducing the speed deviation coefficient Cv of the upper layer of the rectification grid to 41.3 percent 2 The flow field is reduced to 30.4%, the speed deviation is reduced to 22.1% at the position of half a meter above the catalyst layer, and the optimization effect of the flow field is obvious.
2. The uneven distribution of the flue gas in the straight section flue can be effectively improved by additionally arranging the guide plates 1, 2 and 3 at the lower layer of the ammonia spraying grid.
3. After the position of the lower guide plate is adjusted, the pressure drop at the bottom is at most-38 Pa, the pressure drop at the other positions is smaller and less than-10 Pa, the fluxion of the flue gas is improved, and the abrasion degree of the equipment is also reduced.
The foregoing description is only an overview of the present utility model, and is intended to provide a better understanding of the present utility model, as it is embodied in the following description, with reference to the preferred embodiments of the present utility model and the accompanying drawings.
Drawings
FIG. 1 is a schematic diagram of a conventional SCR flue; (a) is a side view of an SCR device; (b) is a perspective view;
FIG. 2 is a schematic view of the structure of an SCR flue according to the present utility model; (a) is a side view of the SCR device after modification of the baffle; (b) is a perspective view;
FIG. 3 is a schematic view of a first baffle arrangement at an inlet of an SCR device of the present utility model;
FIG. 4 is a schematic view of the arrangement of a third baffle at the lower straight section of the ammonia injection grid of the present utility model;
fig. 5 is a schematic view of five sets of fourth baffles for the upper layer of the top rectifying grate according to the present utility model.
Reference numerals in the drawings:
in fig. 1:
1-reducing flue; 2-lower elbow; 3-a lower deflector group; 4-the lower straight section of the ammonia spraying grid; 5-ammonia spraying grids; a 6-ammonia nitrogen mixing region; 7-upper elbow; 8-an upper deflector group; 9-a catalyst layer; 10-rectifying grids; 11-upper layer of rectifying grille;
fig. 2 to 5:
21-a first baffle; 22-a second deflector; 23-a third deflector; 24-a fourth deflector; 25-ammonia spraying grids; 26-rectifying grid; 27-a first layer catalyst; 28-upper elbow baffle; 29-lower elbow baffle.
Detailed Description
The following describes in further detail the embodiments of the present utility model with reference to the drawings and examples. The following examples are illustrative of the utility model and are not intended to limit the scope of the utility model.
Referring to fig. 2, the present embodiment provides a flow guiding optimization device for denitration of flue gas at the tail of a furnace, which includes an upper elbow guide plate 28, a lower elbow guide plate 29, and a first guide plate 21, a second guide plate 22, a third guide plate 23, and a fourth guide plate 24 respectively disposed at four positions of an inlet, a lower elbow, a lower ammonia injection grid layer, and an upper rectifying grid layer of a denitration system; a fourth deflector 24 is arranged behind the upper elbow deflector 28; the second deflector 22 is arranged above said lower elbow deflector 29. The flue gas flows out from the economizer of the tail heating surface of the n-type boiler, the phenomenon of turbulence and large flow speed deviation in the flowing process is obviously weakened through the rectifying action of the guide plate, the ammonia nitrogen is mixed more fully, the uniformity of the flow field in the ammonia injection area and the reaction tower area is improved through calculation, and the denitration efficiency of the device is improved.
Referring to fig. 3, the total of nine first deflectors 21 are provided, and each first deflector 21 is composed of straight deflectors with the same length and inclined deflectors with different inclination angles, so that the flue gas is uniformly distributed in the reducing flue. Nine fold line type guide plates (first guide plates 21) are arranged perpendicular to the pipeline at the inlet of the SCR device and before the reducing flue, and are formed by steel plates made of Q342B materials and are arranged in parallel. The straight sections of each first guide plate 21 have the same length of 420mm, flow out through the inclined section guide plates, the outlets of the inclined sections are parallel, the lengths of the inclined sections are distributed in 1100-2800 mm, the inclined sections and the straight sections are connected through arc guide plates with the radius of 100mm, the horizontal interval between each guide plate is 720mm, and the incoming flow can be uniformly distributed in the reducing flue after entering the guide area.
In this embodiment, there are two second deflectors 22 arranged in parallel above the lower elbow deflector 29, so that the flue gas passing through the lower elbow deflector 29 is inclined to the inner side of the flue, so that the flue gas entering the straight section is uniformly distributed in the whole flue. The two second guide plates at the upper layer of the lower elbow have an angle of 65 degrees and a length of 500mm, so that the flue gas passing through the guide plates at the lower elbow can incline to the inner side of the flue so as to uniformly distribute the flue gas entering the straight section in the whole flue.
Referring to fig. 4, the total of fourteen third deflectors 23 are vertically arranged at the lower part of the straight flue and are filled in the whole straight flue. Fourteen vertical guide plates at the lower part of the straight section flue are arranged at the position 2.5m below the ammonia spraying grid, are arranged in parallel, have the length of 1000mm and the interval of 910mm, are formed by steel plates made of Q342B materials, and can improve the phenomena of turbulent flow and turbulent flow of flue gas entering an ammonia nitrogen mixing area.
Referring to fig. 5, five fourth deflectors 24 are distributed behind the upper elbow deflectors 28, wherein the two fourth deflectors 24 on the upper layer are parallel to the outer contour of the upper elbow, and have an arc length of more than 2000mm, so that the flue gas on the upper elbow can incline to the inner side of the reaction tower after entering the reaction tower; the flow lines at the inlet of the lower three fourth guide plates 24 and at the outlet of the upper elbow guide plate 28 are kept horizontal, the length of the lower guide plate is reduced from top to bottom, the total length of the lowest guide plate is about 580mm, and the bottom guide plates in the lower three fourth guide plates 24 are fold line type guide plates so that the flow lines at the inner side of the flue are obliquely injected into the rectification grid, and the phenomenon of turbulence is avoided.
Referring to fig. 2, the flue gas flowing from the left side uniformly enters the SCR device, firstly flows through the first deflector 21 to make the flue gas uniformly distributed in the reducing flue, then enters the lower elbow, and is led into the rear wall of the pipeline by 4 lower elbow deflectors on the lower side of the elbow and 2 second deflectors 22 on the upper side, so that the flue gas is prevented from flowing in different degrees on the horizontal section due to the pressure loss of the deflectors, then enters the straight pipe flue, the flow line basically along the vertical direction under the flow guiding action of the third deflector 23, then flows into the upper elbow after being fully mixed in the ammonia nitrogen mixing area, is led into the rectifying grid by the fourth deflector 24, and finally enters the catalyst layer to start the reduction reaction. The two sides of the guide plates span the whole flue, the wall surface is used as a support, the straight guide plates are composed of a whole steel plate, and the guide plates with different configurations are connected by welding or machining.
In this embodiment, by changing the positions of two groups of arc straight guide plates (an upper elbow guide plate 28 and a lower elbow guide plate 29) at the existing upper elbow and lower elbow, the length of the straight section at the outlet of the guide plate is lengthened, a multi-stage guide plate is additionally arranged, the distance between the original flue rectification grids is changed, and the horizontal and vertical gaps are reduced to 1/2 of the original distance, so that the streamline entering the grids keeps the vertical downward direction as much as possible, and the method has the following technical effects:
1. after all the guide plates are arranged, the speed deviation Cv of the upper side of the ammonia injection grid 1 Reducing the speed deviation coefficient Cv of the upper layer of the rectification grid to 41.3 percent 2 The flow field is reduced to 30.4%, the speed deviation is reduced to 22.1% at the position of half a meter above the catalyst layer, and the optimization effect of the flow field is obvious.
2. The uneven distribution of the flue gas in the straight section flue can be effectively improved by additionally arranging the guide plates 1, 2 and 3 at the lower layer of the ammonia spraying grid.
3. After the position of the lower guide plate is adjusted, the pressure drop at the bottom is at most-38 Pa, the pressure drop at the other positions is smaller and less than-10 Pa, the fluxion of the flue gas is improved, and the abrasion degree of the equipment is also reduced.
The above description is only of the preferred embodiments of the present utility model and is not intended to limit the present utility model, and it should be noted that it is possible for those skilled in the art to make several improvements and modifications without departing from the technical principle of the present utility model, and these improvements and modifications should also be regarded as the protection scope of the present utility model.
Claims (5)
1. The flow guiding optimization device for denitration of the tail flue gas of the hearth is characterized by comprising an upper elbow guide plate (28), a lower elbow guide plate (29), and a first guide plate (21), a second guide plate (22), a third guide plate (23) and a fourth guide plate (24) which are respectively arranged at the four positions of an inlet of a denitration system, a lower elbow, a lower ammonia injection grid layer and an upper rectifying grid layer; the fourth baffle (24) is arranged behind the upper elbow baffle (28); the second deflector (22) is arranged above the lower elbow deflector (29).
2. The diversion optimization device for denitration of flue gas at the tail part of a hearth according to claim 1, wherein the total number of the first diversion plates (21) is nine, and each first diversion plate (21) consists of straight diversion plates with the same length and inclined diversion plates with different inclination angles and is used for uniformly distributing the flue gas in a reducing flue.
3. The flow guiding optimization device for denitration of flue gas at the tail of a furnace according to claim 2, wherein the number of the second flow guiding plates (22) is two, and the two second flow guiding plates are arranged above the lower elbow flow guiding plates (29) in parallel, and are used for enabling flue gas passing through the lower elbow flow guiding plates (29) to incline to the inner side of a flue so as to enable flue gas entering a straight section to be uniformly distributed in the whole flue.
4. A flow guiding optimization device for denitration of flue gas at the tail part of a furnace according to claim 3, wherein the total number of the third flow guiding plates (23) is fourteen, and the flow guiding optimization device is vertically arranged at the lower part of the straight flue and is filled in the whole straight flue.
5. The diversion optimization device for denitration of tail flue gas of a furnace according to claim 4, wherein the total number of the fourth diversion plates (24) is five, and the four diversion plates are distributed behind the upper elbow diversion plates (28), wherein the upper two fourth diversion plates (24) are parallel to the outer contour of the upper elbow, and are used for enabling the upper flue gas of the upper elbow to incline to the inner side of the reaction tower after entering the reaction tower; the lower three fourth guide plates (24) keep the streamline at the inlet and at the outlet of the upper elbow guide plate (28) horizontal, and the middle bottom guide plates of the lower three fourth guide plates (24) are fold line guide plates for enabling the streamline at the inner side of the flue to be obliquely injected into the rectification grid.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202222995816.5U CN219272672U (en) | 2022-11-10 | 2022-11-10 | Flow guiding optimization device for denitration of tail flue gas of hearth |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202222995816.5U CN219272672U (en) | 2022-11-10 | 2022-11-10 | Flow guiding optimization device for denitration of tail flue gas of hearth |
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| Publication Number | Publication Date |
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| CN219272672U true CN219272672U (en) | 2023-06-30 |
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| CN202222995816.5U Active CN219272672U (en) | 2022-11-10 | 2022-11-10 | Flow guiding optimization device for denitration of tail flue gas of hearth |
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| CN (1) | CN219272672U (en) |
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- 2022-11-10 CN CN202222995816.5U patent/CN219272672U/en active Active
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