SCR (Selective Catalytic Reduction) denitration reactor, SCR denitration device and SCR denitration system
By designing a first catalyst layer with differentiated structures in the SCR denitrification reactor and adjusting the flue gas flow rate, the problems of poor denitrification reaction and excessive ammonia escape caused by flue gas flow rate deviation in the prior art are solved, and more efficient denitrification reaction and lower operating and maintenance costs are achieved.
Patent Information
- Application Number
- CN202420791501.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-04-16
- Publication Date
- 2025-03-11
- Estimated Expiration
- 2034-04-16
AI Technical Summary
The existing SCR denitrification reactors lack uniform gas distribution layer, resulting in large deviations in the flue gas flow rate, excessive or insufficient local ammonia-nitrogen ratio, resulting in poor denitrification reaction effect or excessive ammonia escape.
A differentiated structure-set SCR denitrification reactor is designed. The first catalyst layer is composed of a plurality of catalyst units whose number of outward-inward through-holes gradually increases and the inner diameter of through-holes is gradually shrinks. The flue gas flow rate is adjusted to avoid excessive or insufficient local ammonia-nitrogen ratio.
Through the first catalyst layer arranged in a differentiated structure, the flue gas flow rate is adjusted to make it relatively consistent, improve the denitrification reaction effect, reduce ammonia escape, and reduce equipment operation and maintenance costs.
Smart Images
Figure CN222586126U_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of flue gas treatment, and in particular to an SCR denitration reactor, an SCR denitration device and a system. Background Art
[0002] The working principle of the SCR denitrification device is a very mature flue gas denitrification technology today, and is a post-furnace denitrification treatment method. The principle of the selective catalytic reduction (SCR) flue gas denitrification is to spray the reducing agent ammonia into the flue gas outlet of the boiler economizer, with the flue gas temperature ranging from 300 to 420°C. Under the action of the catalyst, the reducing agent selectively reacts with the nitrogen oxides in the flue gas to generate nitrogen and water.
[0003] In the related art, the catalyst layout of the SCR denitration reactor is mostly a three-layer structure, that is, the catalyst is initially installed in two layers when it is put into operation, and the third layer is added after 24,000 hours (about 3 years). Thereafter, one layer is replaced every 3 years, and the first layer, the second layer, and the third layer are replaced alternately in the order of the first layer, the second layer, and the third layer.
[0004] However, in practical applications, there are still the following technical defects:
[0005] In the related technology, there is no air distribution layer for evenly distributing the airflow, the flue gas flow rate deviation is large, and the local ammonia nitrogen ratio is too high or insufficient, resulting in poor denitrification reaction effect or excessive ammonia escape. The use of additional air distribution plates will increase the equipment operation and maintenance costs. Utility Model Content
[0006] In view of this, the purpose of the utility model is to provide an SCR denitration reactor, the SCR denitration reactor comprising:
[0007] A reactor body, wherein an air inlet is provided on a side wall of the top end of the reactor body, and an air outlet is provided at the bottom end;
[0008] The first catalyst layer is arranged in the reactor body and close to the air inlet; the first catalyst layer comprises a plurality of catalyst units with increasing number of through holes from outside to inside and gradually decreasing inner diameters of the through holes.
[0009] In combination with the first aspect, the first catalyst layer includes:
[0010] A first catalyst unit is located on the center line of the first catalyst layer, and a first number of first through holes are formed on the first catalyst unit;
[0011] The second to Nth catalyst units diffuse outward along the first direction with the first catalyst unit as the center, and the number of second through holes opened on the second to Nth catalyst units gradually decreases, and the inner diameters of the second through holes gradually increase.
[0012] In combination with the first aspect, the Nth catalyst unit comprises:
[0013] The first sub-catalyst unit has two;
[0014] The second sub-catalyst unit is disposed between the two first sub-catalyst units;
[0015] The number of through holes on the first sub-catalyst unit is less than or equal to the number of through holes on the second sub-catalyst unit.
[0016] In combination with the first aspect, the SCR denitration reactor further includes:
[0017] The second catalyst layer is arranged in the reactor body and below the first catalyst layer.
[0018] In combination with the first aspect, the first catalyst layer and the second catalyst layer are respectively detachably connected to the reactor body.
[0019] In combination with the first aspect, the inner wall of the reactor body is made of metal.
[0020] In a second aspect, the present application provides an SCR denitration device, including the SCR denitration reactor as described above, the SCR denitration device is used to perform oxidation-reduction on the flue gas discharged from the boiler flue to remove nitrogen oxides in the flue gas.
[0021] In combination with the second aspect, the SCR denitration device includes:
[0022] The connecting pipe is in a right-angle structure, one end of which is connected to the smoke source and the other end is connected to the air inlet;
[0023] The ammonia spraying grid is arranged in the connecting pipe and is used to spray the reducing agent into the connecting pipe so that the flue gas and the reducing agent are fully mixed.
[0024] In a third aspect, the present application provides an SCR denitration system, comprising the SCR denitration device as described above.
[0025] In combination with the third aspect, the SCR denitration system further includes a control mechanism, which is connected to the ammonia injection grid in the SCR denitration device.
[0026] The embodiments of the utility model bring the following beneficial effects: the embodiments of the utility model provide an SCR denitration reactor, an SCR denitration device and a system, the SCR denitration reactor comprising: a reactor body, an air inlet is provided on a side wall of the top end of the reactor body, and an air outlet is provided at the bottom end; a first catalyst layer is arranged in the reactor body and close to the air inlet; the first catalyst layer comprises a plurality of catalyst units whose number of through holes gradually increases from the outside to the inside and whose inner diameters of the through holes gradually decrease.
[0027] The first catalyst layer in the SCR denitrification reactor provided in the present application has a differentiated structural setting. The catalyst unit located at the edge has a small number of through holes with large pore diameters, while the catalyst unit located inside has a large number of through holes with smaller pore diameters. The flue gas flow rate at the edge can be slowed down, so that the flue gas flow rate flowing through the first catalyst layer is relatively consistent, avoiding excessive or insufficient local ammonia-nitrogen ratio, improving the denitrification reaction effect, reducing ammonia escape, and no additional structure is required, thereby reducing catalyst wear, extending the service life of the catalyst, and low equipment operation and maintenance costs.
[0028] Other features and advantages of the utility model will be described in the following description, and partly become apparent from the description, or understood by practicing the utility model. The purpose and other advantages of the utility model are realized and obtained by the structures specifically pointed out in the description, claims and drawings.
[0029] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS
[0030] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without paying any creative work.
[0031] Figure 1 A schematic diagram of the structure of the SCR denitrification device provided for this application;
[0032] Figure 2 This is a schematic diagram of the structure of the first catalyst layer in the SCR denitration device provided in this application;
[0033] Figure 3 This is a schematic diagram of the structure of the Nth catalytic unit in the SCR denitration device provided in this application;
[0034] Figure 4 This is an example diagram of the arrangement of the number of through holes of the first to Nth catalyst units in the SCR denitration device provided in the present application.
[0035] The reference numerals are as follows:
[0036] 1-reactor body, 11-gas outlet, 2-first catalyst layer, 210-first catalyst unit, 211-second catalyst unit, 212-third catalyst unit, 22-first sub-catalyst unit, 23-second sub-catalyst unit, 3-second catalyst layer, 4-ammonia injection grid, 5-connecting pipe. DETAILED DESCRIPTION
[0037] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution of the present application will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.
[0038] To facilitate understanding of this embodiment, the following is a brief introduction to the technologies involved in this application.
[0039] Selective catalytic reduction is the most widely used flue gas denitrification technology. This method mainly uses ammonia as a reducing agent to selectively reduce nitrogen oxides into nitrogen and water. It has the advantages of no by-products, no secondary pollution, simple device structure, high removal efficiency, reliable operation, and easy maintenance. Within a certain temperature range, under the action of a catalyst and the presence of oxygen, NH3 preferentially undergoes a reduction and removal reaction with NO to generate N2 and water, rather than an oxidation reaction with oxygen in the flue gas, so the denitrification effect is better than that of non-selective reducing agents.
[0040] After introducing the technical terms involved in this application, the application scenarios and design concepts of the embodiments of this application are briefly introduced.
[0041] In the related technology, there is no air distribution layer for uniform airflow, the flue gas flow rate deviation is large, and the local ammonia nitrogen ratio is too high or insufficient, resulting in poor denitrification reaction effect or excessive ammonia escape. The use of additional air distribution plates will increase the equipment operation and maintenance costs.
[0042] Based on this, the embodiments of the present application provide an SCR denitrification reactor, an SCR denitrification device and a system, which adjust the flue gas flow rate through a first catalyst layer with a differentiated structure, avoid excessive or insufficient local ammonia-nitrogen ratio, improve the denitrification reaction effect, and reduce ammonia escape.
[0043] Example 1
[0044] The present application provides an SCR denitration reactor, combined with Figure 1 As shown, the SCR denitration reactor includes: a reactor body 1 and a first catalyst layer 2 .
[0045] An air inlet is provided on one side wall of the top of the reactor body 1 , and an air outlet 11 is provided at the bottom.
[0046] The first catalyst layer 2 is arranged in the reactor body 1 and close to the air inlet; the first catalyst layer 2 includes a plurality of catalyst units with increasing number of through holes from the outside to the inside and gradually decreasing inner diameters of the through holes.
[0047] The first catalyst layer 2 in the SCR denitrification reactor provided in the present application has a differentiated structural setting. The catalyst unit located at the edge has a small number of through holes with large pore diameters, while the catalyst unit located inside has a large number of through holes with small pore diameters. This can slow down the flue gas flow rate at the far corner side and increase the flue gas flow rate at the near corner to avoid blockage, so that the flue gas flow rate flowing through the first catalyst layer 2 is relatively consistent, avoiding excessive or insufficient local ammonia-nitrogen ratio, improving the denitrification reaction effect, reducing ammonia escape, and does not require the addition of additional structures, with low equipment operation and maintenance costs.
[0048] In combination with the first aspect, the first catalyst layer 2 includes: a first catalyst unit 210, and second to Nth catalyst units.
[0049] The first catalyst unit 210 is located on the center line of the first catalyst layer, and a first number of first through holes are formed on the first catalyst unit 210;
[0050] The second to Nth catalyst units spread outward along the first direction with the first catalyst unit 210 as the center, and the number of second through holes opened on the second to Nth catalyst units gradually decreases, and the inner diameters of the second through holes gradually increase.
[0051] Combination Figure 2 As shown, since the reaction zone of the existing SCR denitration reactor is mostly a rectangular parallelepiped structure, the first catalyst layer 2 arranged at the reaction zone in the SCR denitration reactor should be adapted to the shape of the reaction zone. In this embodiment, taking the first catalyst layer 2 in the reaction zone as a square structure as an example, the horizontal direction thereof is the first direction, the depth direction of the same plane as the horizontal direction is the second direction, and the first direction is perpendicular to the second direction.
[0052] Each catalyst unit is connected or close to the two inner walls of the SCR denitration reactor along the second direction. Along the first direction, i.e., the horizontal direction shown in the figure, the catalyst unit located at the horizontal center is the first catalyst unit 210, and the one located outside the first catalyst unit 210 is the second catalyst unit 211. It can be understood that the one located outside the second catalyst unit 211 is the third catalyst unit 212 (combined with Figure 2 As shown), and continues to diffuse outward until a first catalyst layer 2 consisting of N catalyst units is obtained.
[0053] Combined with the first aspect, Figure 3 As shown, the Nth catalyst unit includes: two first sub-catalyst units 22 and a second sub-catalyst unit 23 .
[0054] A second sub-catalyst unit 23 is disposed between the two first sub-catalyst units 22 ; wherein the number of through holes on the first sub-catalyst unit 22 is less than or equal to the number of through holes on the second sub-catalyst unit 23 .
[0055] Combination Figure 4 An exemplary schematic diagram of the number of through holes of the first to Nth catalyst units is provided. It can be understood that the Nth catalyst unit is the catalyst unit located at the outermost side of the first catalyst layer 2. The two sides are the near corner side and the far corner side where the flue gas enters the SCR denitration reactor. The flue gas flow rate on the far corner side should be faster than other positions, while the flue gas flow rate on the near corner side is low, and fly ash is easily accumulated to cause blockage. Therefore, it is necessary to adjust the flue gas flow rate to avoid the flue gas flow rate being too fast and not fully reacting with the catalyst before flowing out of the SCR denitration reactor or the first catalyst layer being blocked. In this embodiment, the number of through holes is reduced and the aperture is increased on both the near corner side and the far corner side. Blockage can be effectively avoided on the near corner side, and the flow area is increased on the far corner side. The flue gas flow rate will be reduced, which can extend the contact time with the catalyst and reduce the wear of the first catalyst layer caused by air flow scouring.
[0056] Furthermore, the number of through holes at the four corners should be further reduced and the aperture of the through holes should be increased to further optimize and adjust the flue gas velocity at the four corners, so that the flue gas flow rate flowing through each part of the first catalyst layer 2 is relatively uniform and consistent.
[0057] Combination Figure 4 As shown, in this embodiment, the step length of adjusting the number of through holes is 2. The specific value can be adjusted according to actual practical needs, for example, it can be a multiple of 2, or other integers such as 3, 5, 9, etc., which are not limited here.
[0058] In combination with the first aspect, the SCR denitration reactor further includes: a second catalyst layer 3 is arranged in the reactor body 1 and below the first catalyst layer 2 .
[0059] In the related art, each denitrification reactor has three catalyst layers. When in use, two catalyst layers are initially assembled. After the operation cycle (generally 3 years) is reached, the activity of the catalyst decreases, and the catalyst layer of the first layer cannot meet the denitrification efficiency requirements. At this time, the third catalyst layer is added, and a new catalyst layer is used in conjunction with the two catalyst layers with lower catalyst activity. After that, the catalyst layer is replaced every three years in a cycle.
[0060] However, in actual application, the catalyst layer has resistance to the flue gas flow, and each layer has a resistance of about 200Pa. The combined use of three catalyst layers has a great resistance to the flue gas flow, and the three catalyst layers wear out at the same time, and the mechanical life decays relatively quickly, resulting in high equipment operation and maintenance costs.
[0061] In this embodiment, the SCR denitration reactor has only two catalyst layers, namely the first catalyst layer 2 and the second catalyst layer 3. When the operation cycle is reached (combined with the above operation cycle, it is generally 3 years), the new first catalyst layer 2 and the new second catalyst layer 3 are used to replace the existing two catalyst layers, and the two removed catalyst layers are regenerated for replacement after three years, and the operation is cyclically operated according to this scheme. In this way, the catalyst activity of the two catalyst layers used each time is 100%, which can meet the actual denitration needs, and can be disassembled and regenerated every three years for standby use. Compared with the existing scheme, the wear is small and its service life can be extended. Therefore, the equipment operation and maintenance costs are effectively controlled.
[0062] In combination with the first aspect, the first catalyst layer 2 and the second catalyst layer 3 are respectively detachably connected to the reactor body 1 .
[0063] The detachable installation method allows for timely replacement and repair, which is conducive to smooth equipment maintenance.
[0064] As one feasible method, a mounting frame is provided on the inner wall of the reactor body 1, and the first catalyst layer 2 and the second catalyst layer 3 are respectively installed on the mounting frame; as another feasible method, a slide groove is provided on the inner wall of the reactor body 1, and the first catalyst layer 2 and the second catalyst layer 3 are respectively slid and pushed into the corresponding slide grooves.
[0065] The above examples provide two feasible installation methods. In actual application, other installation methods may be used and are not limited here.
[0066] In combination with the first aspect, the inner wall of the reactor body 1 is made of metal.
[0067] Since the reactor body 1 is at a relatively high temperature (about 400° C.) for a long time, a metal material with a relatively high melting point and a stable structure is generally selected.
[0068] In a second aspect, the present application provides an SCR denitration device, including the SCR denitration reactor as described above, the SCR denitration device is used to perform oxidation-reduction on the flue gas discharged from the boiler flue to remove nitrogen oxides in the flue gas.
[0069] Combined with the second aspect, combined Figure 1 As shown, the SCR denitration device also includes: a connecting pipe 5 and an ammonia injection grid 4.
[0070] One end of the connecting pipe 5 in a right-angle structure is connected to the smoke source, and the other end is connected to the air inlet;
[0071] The ammonia injection grid 4 is arranged in the connecting pipe 5 and is used to inject the reducing agent into the connecting pipe 5 so that the flue gas reducing agent in the connecting pipe 5 is fully mixed.
[0072] In a third aspect, the present application provides an SCR denitration system, comprising the SCR denitration device as described above.
[0073] In combination with the third aspect, the above-mentioned SCR denitration system further includes a control mechanism (not shown in the figure), and the control mechanism is connected to the ammonia injection grid 4 in the SCR denitration device.
[0074] It can be understood that the control mechanism controls the diluted ammonia to enter the ammonia injection grid 4 in the connecting pipe 5 through the nozzle, and the ammonia is mixed with the flue gas in the connecting pipe 5. Under the action of the catalyst, the nitrogen oxides in the flue gas react chemically with the ammonia, selectively reacting NOx to generate non-toxic and non-polluting N2 and H2O.
[0075] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process of the system and device described above can refer to the corresponding process in the aforementioned method embodiment, and will not be repeated here.
[0076] In addition, in the description of the embodiments of the present application, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For those skilled in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.
[0077] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.
[0078] Finally, it should be noted that the above embodiments are only specific implementation methods of the present application, which are used to illustrate the technical solutions of the present application, rather than to limit them. The protection scope of the present application is not limited thereto. Although the present application is described in detail with reference to the above embodiments, those skilled in the art should understand that any person skilled in the art who is familiar with the technical field can still modify the technical solutions recorded in the above embodiments within the technical scope disclosed in the present application, or can easily think of changes, or make equivalent replacements for some of the technical features therein; and these modifications, changes or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.
Claims
1. An SCR denitration reactor, characterized in that: The SCR denitration reactor comprises: A reactor body, wherein an air inlet is provided on a side wall of the top end of the reactor body, and an air outlet is provided at the bottom end; The first catalyst layer is arranged in the reactor body and close to the air inlet; the first catalyst layer includes a plurality of catalyst units with increasing number of through holes from outside to inside and gradually decreasing inner diameters of the through holes.
2. The SCR denitration reactor according to claim 1, characterized in that: The first catalyst layer comprises: A first catalyst unit is located on the center line of the first catalyst layer, and a first number of first through holes are formed on the first catalyst unit; The second to Nth catalyst units diffuse outward along the first direction with the first catalyst unit as the center, and the number of second through holes opened on the second to Nth catalyst units gradually decreases, and the inner diameters of the second through holes gradually increase.
3. The SCR denitration reactor according to claim 2, characterized in that: The Nth catalyst unit comprises: The first sub-catalyst unit has two; A second sub-catalyst unit is disposed between two of the first sub-catalyst units; The number of through holes on the first sub-catalyst unit is less than or equal to the number of through holes on the second sub-catalyst unit.
4. The SCR denitration reactor according to claim 1, characterized in that: The SCR denitration reactor further comprises: The second catalyst layer is arranged in the reactor body and below the first catalyst layer.
5. The SCR denitration reactor according to claim 4, characterized in that: The first catalyst layer and the second catalyst layer are respectively detachably connected to the reactor body.
6. The SCR denitration reactor according to claim 1, characterized in that: The inner side wall of the reactor body is made of metal.
7. An SCR denitration device, characterized in that: It comprises the SCR denitration reactor as claimed in any one of claims 1 to 6, wherein the SCR denitration device is used to perform oxidation-reduction on the flue gas discharged from the boiler flue to remove nitrogen oxides in the flue gas.
8. The SCR denitration device according to claim 7, characterized in that: include: The connecting pipe is in a right-angle structure, one end of which is connected to the smoke source and the other end is connected to the air inlet; The ammonia spraying grid is arranged in the connecting pipe and is used for spraying the reducing agent into the connecting pipe so that the flue gas and the reducing agent are fully mixed.
9. An SCR denitration system, characterized in that: It comprises the SCR denitration device as described in any one of claims 7-8.
10. The system according to claim 9, characterized in that The system further comprises a control mechanism, which is connected to an ammonia injection grid in the SCR denitration device.