Denitration assembly, ammonia spraying grid and mounting structure of ammonia spraying grid
By designing a cyclone-like ammonia spray structure and a mesh ammonia spray grille, the problems of poor ammonia spray mixing and blockage are solved, and efficient ammonia smoke mixing and anti-blocking effect are achieved, reducing equipment cost and flow resistance.
Patent Information
- Application Number
- CN202422695829.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-05
- Publication Date
- 2025-08-22
- Estimated Expiration
- 2034-11-05
AI Technical Summary
In the existing SCR denitrification device, the ammonia spraying mixing effect is poor, and the ammonia spraying grid is easily blocked, which makes it difficult to adjust the molar ratio of ammonia nitrogen, reduces the denitrification efficiency, and increases equipment investment and flow resistance.
A denitrification component is designed, and the ammonia sprayed is swirling. It is arranged through the specific angle between the ammonia spray tube and the branch lead-out tube to avoid hedging the nozzle and the smoke gas flow, enhance the mixing effect and prevent blockage, and adopt a mesh ammonia spray grid structure and reasonable installation method.
It improves the mixing effect of ammonia smoke, avoids breathing and blockage of nozzles, reduces flow resistance, reduces equipment costs, and ensures denitrification efficiency and equipment stability.
Smart Images
Figure CN223249098U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the field of denitration, in particular to a denitration component, an ammonia injection grid and an installation structure of the ammonia injection grid. Background Art
[0002] At present, large power plants generally use SCR denitrification devices to reduce NO in flue gas. x Emission concentration. SCR uses NH3 to NO x The reduction characteristics of NO x It is reduced to N2 and H2O which are harmless to the environment. In actual operation, the control of ammonia injection amount is particularly critical. Increasing the ammonia injection amount is conducive to reducing NO x Emission concentration, but ammonia escape will increase, which will cause the downstream air preheater to be blocked and corroded due to ammonium bisulfate deposition. In terms of ammonia injection control, in addition to reasonably controlling the total amount of ammonia injection, attention should also be paid to the uniformity of ammonia injection to ensure that NO x The emission concentration meets the standards.
[0003] Ammonia injection grids (AIGs) are key components of ammonia injection systems and are often located in the vertical flue at the inlet of the denitrification system. To prevent the nozzles from colliding with the flue gas flow, which could cause air to suffocate in the AIG pipes, the gas in the pipes is generally ejected downwind, resulting in poor ammonia-to-fume mixing. Furthermore, to ensure ammonia injection velocity and coverage, the nozzles on AIGs are typically very small in diameter and densely arranged, a layout that can easily lead to nozzle clogging. Poor ammonia-to-fume mixing and AIG nozzle clogging can make it difficult to balance the ammonia-nitrogen molar ratio and reduce denitrification efficiency.
[0004] In order to enhance the ammonia smoke mixing effect and avoid clogging of the ammonia spray grid, the current common engineering practice is to increase the nozzle size of the ammonia spray grid, reduce the number of nozzles and simultaneously add an ammonia smoke mixer. Although the ammonia smoke mixer enhances the ammonia smoke mixing effect, it also increases the smoke flow resistance and increases the initial investment in the equipment. Utility Model Content
[0005] The purpose of this utility model is to overcome the problems of poor flue gas and ammonia mixing and easy clogging of ammonia injection grids in the prior art, and to provide a denitrification assembly, an ammonia injection grid, and an ammonia injection grid mounting structure. The ammonia gas ejected by the denitrification assembly provided by the utility model is in a swirling flow, which is conducive to improving the mixing effect with the surrounding flue gas, while also avoiding the suffocation caused by the impact of the nozzle and the flue gas flow, and alleviating the problem of nozzle clogging.
[0006] In order to achieve the above-mentioned object, the first aspect of the present invention provides a denitration assembly, which includes an ammonia injection branch pipe and an ammonia injection head, wherein the ammonia injection head includes at least two branch outlet pipes, all of which are located in the same plane, and their air inlet ends are simultaneously connected to the ammonia injection branch pipe, and the exhaust ends of all of the branch outlet pipes are respectively connected to an ammonia injection pipe;
[0007] Among them, the plane where all the branch outlet pipes are located is taken as the reference plane, the angle between the ammonia injection pipe and the reference plane is α, and the angle between the projection of the ammonia injection pipe on the reference plane and the corresponding branch outlet pipe is β, 0°<α, β≤90°.
[0008] By adopting the above technical solution, the plane where the branch outlet pipes are located is used as the horizontal plane. When in use, the direction of the flue gas flow is generally perpendicular to the plane where the branch outlet pipes are located. Since the ammonia spray pipes and the corresponding branch outlet pipes have a certain angle in both the horizontal and vertical directions, after the ammonia is sprayed from the ammonia spray pipes, the ammonia flows of each channel will form an overall and / or local vortex, which is beneficial to improve the mixing effect with the surrounding flue gas. At the same time, it can also avoid the suffocation caused by the collision between the ammonia spray pipe nozzle and the flue gas flow, thereby alleviating the blockage of the ammonia spray pipe nozzle.
[0009] Preferably, all ammonia injection pipes are arranged in a clockwise or counterclockwise pattern around the intersection of the air inlet ends of all the branch outlet pipes. With this structure, the ammonia flows from each ammonia injection pipe flow in the same direction, superimposing to create an overall swirl flow, further enhancing the smoke and ammonia mixing effect.
[0010] Preferably, the centerlines of all the ammonia injection pipes are tangent to the same inscribed circle, the center of which coincides with the intersection of all the branch outlet pipes. With this structure, the branch outlet pipes and the ammonia injection branch pipe are of equal length, and the horizontal and vertical deviation angles of each ammonia injection pipe from the corresponding branch outlet pipe are independently identical. This ensures that the center of the ammonia cyclone formed by each ammonia injection pipe is the intersection of all the branch outlet pipes. The ammonia flows ejected from each ammonia injection pipe overlap to form a more powerful cyclone, further improving the smoke and ammonia mixing effect.
[0011] Preferably, with the intersection of all the branch outlet pipes as the center, all the ammonia injection pipes are distributed in a clockwise shape with the intersection as the center.
[0012] Preferably, 20°≤α≤70°. This structure facilitates processing and installation, expands the ammonia spray range, enhances the ammonia-smoke mixing effect, and avoids the impact with the smoke flow, enhancing the anti-blocking effect. α can be any value between any two of 20°, 30°, 40°, 50°, 60°, and 70°.
[0013] Preferably, 15°≤β≤45°. This structure is convenient for processing and installation, and is conducive to forming a swirl-shaped ammonia flow, improving the smoke and ammonia mixing effect. β can be any value between any two numbers among 15°, 20°, 25°, 30°, 35°, 40°, and 45°.
[0014] Preferably, 40°≤α≤50°, 25°≤β≤35°. With this structure, both the smoke and ammonia mixing effect and the anti-blocking effect are optimal.
[0015] Preferably, the ammonia injection branch pipe is parallel to the branch outlet pipe, and the outlet end of the ammonia injection branch pipe is connected to the air inlet end of the branch outlet pipe through a transition pipe. This structure can improve the support strength of the ammonia injection head through the transition pipe, improving the stability and reliability of the entire structure.
[0016] Preferably, the ammonia spray head includes four branch outlet pipes and an equal number of ammonia spray pipes, with the angle between adjacent branch outlet pipes being 90°. This structure is simple, easy to manufacture, and facilitates the formation of a swirling ammonia flow.
[0017] A second aspect of the present invention provides an ammonia injection grid, which comprises at least two denitration assemblies according to the first aspect of the present invention, wherein the ammonia injection branch pipes of each denitration assembly are distributed along the same straight line direction and / or in parallel.
[0018] By adopting the above technical solution, a plurality of denitrification components are combined and arranged to form an ammonia injection grid, and the branch outlet pipes of the ammonia injection grid form a network distribution, which is beneficial to improving the smoke and ammonia mixing effect.
[0019] The third aspect of the present invention provides an installation structure of an ammonia injection grid, which includes the ammonia injection grid described in the second aspect of the present invention, and the ammonia injection grid is installed in the flue, the flue gas flow direction in the flue is perpendicular to the reference plane where the branch outlet pipe is located, and the flue gas flow direction in the flue flows from the reference plane toward the ammonia injection pipe.
[0020] By adopting the above technical solution, there is a certain angle between the flue gas flow direction and the ammonia flow ejected from the ammonia injection pipe, which can effectively prevent the collision between the ammonia injection pipe and the flue gas, thereby avoiding suffocation. At the same time, it also expands the ammonia injection range and easily carries out the sediment in the pipe. It has excellent anti-blocking performance and does not require a separate ammonia smoke mixer, thereby reducing the flue gas flow resistance and reducing costs.
[0021] Compared with the prior art, the denitration assembly, ammonia injection grid, and the installation structure of the ammonia injection grid provided by the present invention have the following advantages:
[0022] (1) The ammonia is sprayed into the flue in a swirling manner, which effectively ensures the mixing effect of ammonia and smoke, and also avoids the suffocation caused by the collision between the ammonia spray nozzle and the smoke flow;
[0023] (2) Each ammonia spraying tube has a certain angle with the direction of flue gas flow, which can effectively prevent the nozzle from colliding with the flue gas, thereby avoiding suffocation, and at the same time expand the ammonia spraying range, and easily carry out the sediment in the tube, with excellent anti-blocking performance;
[0024] (3) There is no need to set up a separate ammonia smoke mixer, which reduces the flow resistance of the smoke and reduces costs. BRIEF DESCRIPTION OF THE DRAWINGS
[0025] Figure 1 This is a schematic diagram of the structure of the denitrification component (the arrow in the figure indicates the injection direction of ammonia);
[0026] Figure 2 It is a schematic diagram of the three-dimensional structure of the ammonia injection grid;
[0027] Figure 3 This is a schematic diagram of the planar structure of the ammonia injection grid (the arrow in the figure is the direction of flue gas flow);
[0028] Figure 4 yes Figure 3 Left view of;
[0029] Figure 5 yes Figure 3 Top view of .
[0030] Description of Reference Numerals
[0031] 1- ammonia injection branch pipe; 11- transition pipe; 2- ammonia injection head; 21- branch outlet pipe; 22- ammonia injection pipe. DETAILED DESCRIPTION
[0032] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on the specific circumstances.
[0033] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.
[0034] The term "connected" in this application means connected and communicating.
[0035] Example 1
[0036] like Figure 1 、 3 As shown in Figure 4, a denitrification assembly comprises an ammonia injection branch pipe 1 and an ammonia injection head 2, wherein the ammonia injection head 2 comprises at least two branch outlet pipes 21, all of the branch outlet pipes 21 are located in the same plane, and their air inlet ends are simultaneously connected to the ammonia injection branch pipe 1, and the exhaust ends of all the branch outlet pipes 21 are respectively connected to an ammonia injection pipe 22;
[0037] The plane where all the branch outlet pipes 21 are located is taken as the reference plane, the angle between the ammonia injection pipe 22 and the reference plane is α, and the angle between the projection of the ammonia injection pipe 22 on the reference plane and the corresponding branch outlet pipe 21 is β, 0°<α, β≤90°.
[0038] Specifically, the angle between the ammonia injection pipe 22 and the reference plane refers to the angle between the tube centerline of the ammonia injection pipe 22 and the reference plane, and the angle between the projection of the ammonia injection pipe 22 on the reference plane and the corresponding branch outlet pipe 21 refers to the angle between the projection of the tube centerline of the ammonia injection pipe 22 on the reference plane and the tube centerline of the corresponding branch outlet pipe 21.
[0039] In order to better form an ammonia cyclone, with the intersection of the air inlet ends of all the branch outlet pipes 21 as the center, all the ammonia injection pipes 22 are distributed in a clockwise or counterclockwise shape with the intersection as the center. In this example, it is preferably distributed counterclockwise. The lengths of all the branch outlet pipes 21 are equal, and the lengths of all the ammonia injection pipes 22 are equal. The angle α between the center line of each ammonia injection pipe 22 and the reference plane is the same, and the angle β between the projection of the center line of each ammonia injection pipe 22 on the reference plane and the center line of the corresponding branch outlet pipe 21 is the same, so that the center lines of all the ammonia injection pipes 22 are tangent to the same inscribed circle, and the center of the inscribed circle coincides with the intersection of all the branch outlet pipes 21.
[0040] In order to better support the ammonia injection head 2, the ammonia injection branch pipe 1 is parallel to the branch outlet pipe 21, and the outlet end of the ammonia injection branch pipe 1 is connected to the air inlet end of the branch outlet pipe 21 through a transition pipe 11. The transition pipe 11 is perpendicular to the corresponding ammonia injection branch pipe 1 and the branch outlet pipe 21.
[0041] In some embodiments, the ammonia injection head 2 includes four branch outlet pipes 21 and the same number of ammonia injection pipes 22 as the branch outlet pipes 21 , and the angle between adjacent branch outlet pipes 21 is 90°.
[0042] The specific angles of α and β can be selected according to production needs. In some embodiments, 20°≤α≤70°, 15°≤β≤45°, preferably 40°≤α≤50°, 25°≤β≤35°. In this example, α is 45° and β is 35°.
[0043] Example 2
[0044] like Figure 2-5 As shown, an ammonia injection grid comprises at least two denitration assemblies according to embodiment 1, wherein the ammonia injection branch pipes 1 of each denitration assembly are distributed along the same straight line direction and / or in parallel.
[0045] like Figure 5 As shown, there are multiple ammonia injection branch pipes 1 of the denitrification components extending and distributed along the first straight line direction, and there are also multiple ammonia injection branch pipes 1 of the denitrification components distributed in parallel along the second straight line direction. The first straight line direction and the second straight line direction are perpendicular to each other, thereby forming a grid structure of the branch outlet pipes 21 of each denitrification component.
[0046] In this example, there are specifically 10 ammonia injection components distributed in a matrix of two rows and five columns, wherein there are five columns distributed in parallel in the first straight line direction and two rows distributed in the second straight line direction.
[0047] Example 3
[0048] An installation structure for an ammonia injection grid, comprising the ammonia injection grid according to embodiment 2, wherein the ammonia injection grid is installed in a flue, such as Figure 3 As shown, the flue gas flow direction in the flue is perpendicular to the reference plane where the branch outlet pipe 21 is located, and the flue gas flow direction in the flue flows from the reference plane to the ammonia injection pipe 22, so that the ammonia injection pipe 22 of each ammonia injection assembly has a certain angle with the flue gas flow direction, which can effectively prevent the nozzle and the flue gas from colliding, thereby avoiding suffocation, and at the same time expanding the ammonia injection range, and easily carrying out the sediment in the pipe, and having excellent anti-blocking performance; there is no need to set up a separate ammonia smoke mixer, which reduces the flue gas flow resistance and reduces the cost.
[0049] When in use, in order to facilitate the connection of the ammonia supply pipeline, the inlet end of each ammonia injection branch pipe 1 can be extended to the outside of the flue and connected to the ammonia injection zone header or the ammonia injection main pipe. The diameter of the ammonia injection pipe 22 is DN50, and the arrangement density is 4 / m 2 .
[0050] Taking α as 45° and β as 35° as an example, when spraying ammonia, ammonia passes through the ammonia spray branch pipe 1 and the branch outlet pipe 21, and is sprayed from the ammonia spray pipe 22, and the four ammonia spray pipes 22 of the same ammonia spray head 2 form a swirl ammonia spray. The applicant used CFD numerical simulation technology analysis and practical verification. With the above structure, the diffusion range of ammonia is wider, and the ammonia smoke mixing effect is effectively ensured. The unevenness coefficient of the ammonia nitrogen molar ratio of the first layer cross section of the denitrification catalyst is less than 0.05, and it is easy to carry out the sediment in the pipe, and effectively prevent the nozzle and the flue gas from colliding, solving the problem of easy clogging of ordinary ammonia spray grids. It has been running stably for 18 months without clogging, and there is no need to set up an ammonia smoke mixer, which reduces the flow resistance of the flue gas and reduces the cost.
[0051] The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited thereto. Within the technical concept of the present invention, various simple modifications may be made to the technical solution of the present invention. For example, the lifting structure may be changed to another mechanical lifting structure, including combining various specific technical features in any suitable manner. To avoid unnecessary repetition, the present invention will not further describe various possible combinations. However, these simple modifications and combinations should also be considered as the contents disclosed by the present invention and fall within the scope of protection of the present invention.
Claims
1. A denitrification component, characterized in that: The denitration assembly includes an ammonia injection branch pipe and an ammonia injection head, wherein the ammonia injection head includes at least two branch outlet pipes, all of which are located in the same plane, and their air inlet ends are simultaneously connected to the ammonia injection branch pipe, and the exhaust ends of all of the branch outlet pipes are respectively connected to an ammonia injection pipe; Among them, the plane where all the branch outlet pipes are located is taken as the reference plane, the angle between the ammonia injection pipe and the reference plane is α, and the angle between the projection of the ammonia injection pipe on the reference plane and the corresponding branch outlet pipe is β, 0°<α, β≤90°.
2. The denitration component according to claim 1, characterized in that: With the intersection of the air inlet ends of all the branch outlet pipes as the center, all the ammonia injection pipes are distributed in a clockwise or counterclockwise shape with the intersection as the center.
3. The denitration component according to claim 1 or 2, characterized in that: The center lines of all the ammonia injection pipes are tangent to the same inscribed circle, and the center of the inscribed circle coincides with the intersection point of all the branch outlet pipes.
4. The denitration component according to claim 3, characterized in that: 20°≤α≤70°。 5. The denitration component according to claim 4, characterized in that: 15°≤β≤45°。 6. The denitration component according to claim 5, characterized in that: 40°≤α≤50°，25°≤β≤35°。 7. The denitration assembly according to any one of claims 4 to 6, characterized in that: The ammonia injection branch pipe is parallel to the branch outlet pipe, and the outlet end of the ammonia injection branch pipe is connected to the air inlet end of the branch outlet pipe through a transition pipe.
8. The denitration assembly according to claim 7, characterized in that: The ammonia injection head includes four branch outlet pipes and the same number of ammonia injection pipes as the branch outlet pipes, and the angle between adjacent branch outlet pipes is 90°.
9. An ammonia injection grid, characterized in that: The invention comprises at least two denitration components according to any one of claims 1 to 8, wherein the ammonia injection branch pipes of each denitration component are distributed along the same straight line direction and / or in parallel.
10. An installation structure for an ammonia injection grid, characterized in that: Including the ammonia injection grid as described in claim 9, the ammonia injection grid is installed in the flue, the flue gas flow direction in the flue is perpendicular to the reference plane where the branch outlet pipe is located, and the flue gas flow direction in the flue flows from the reference plane toward the ammonia injection pipe.