Flue gas low-temperature denitration device
By installing a spiral ammonia injection pipe in the inlet pipe of the low-temperature denitrification device and an arc-shaped ammonia injection pipe in the tower body for pre-mixing and secondary mixing, the problem of uneven mixing of flue gas and ammonia is solved, and the fullness and effectiveness of the denitrification reaction are improved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- SUZHOU XITU ENVIRONMENTAL PROTECTION TECH CO LTD
- Filing Date
- 2025-08-05
- Publication Date
- 2026-07-10
AI Technical Summary
In existing low-temperature denitrification devices, the flue gas and the denitrification agent ammonia are not mixed evenly, resulting in insufficient denitrification reaction and poor denitrification effect.
A spiral ammonia injection pipe is installed in the inlet pipe of the flue gas entering the denitrification unit for pre-mixing, and an arc-shaped ammonia injection pipe is installed in the tower body for secondary mixing, to ensure that the flue gas and ammonia are fully mixed before entering the catalyst layer for reaction.
By premixing and secondary mixing, the problem of uniform mixing of flue gas and ammonia was solved, and the sufficiency and effectiveness of the denitrification reaction were improved.
Smart Images
Figure CN224474868U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of waste gas treatment technology, and in particular relates to a low-temperature denitrification device for flue gas. Background Technology
[0002] With increasingly stringent environmental regulations limiting nitrogen oxide emissions, coal-fired power plants, as major sources of emissions, face immense pressure to reduce emissions. Traditional medium- and high-temperature selective catalytic reduction (SCR) denitrification technology cannot directly treat low-temperature flue gas. Heating the low-temperature flue gas would significantly increase energy consumption and costs. Against this backdrop, low-temperature denitrification technology has emerged, capable of denitrification at 100–300°C, avoiding the need for additional heating.
[0003] However, due to defects in the pipeline design of existing low-temperature denitrification devices, the flue gas and the denitrification agent (ammonia) are not mixed evenly before entering the catalyst layer to react, resulting in insufficient denitrification reaction and poor denitrification effect.
[0004] Therefore, how to avoid uneven mixing of the denitrification agent (ammonia) with the flue gas, which would lead to incomplete denitrification reaction, is a technical problem that urgently needs to be solved by those skilled in the art.
[0005] It should be noted that the information disclosed in this background section is only for understanding the background technology of this application concept, and therefore, the above description is not considered to constitute prior art information. Utility Model Content
[0006] This disclosure provides at least one low-temperature flue gas denitrification device.
[0007] In a first aspect, embodiments of this disclosure provide a low-temperature flue gas denitrification device, comprising:
[0008] The tower body has an air outlet pipe at the top and an air inlet pipe on the bottom side wall;
[0009] An arc-shaped ammonia injection pipe is installed at the bottom of the tower.
[0010] The spiral ammonia injection pipe has one end connected to the arc-shaped ammonia injection pipe and the other end extending into the air intake pipe.
[0011] The catalyst is positioned above the arc-shaped ammonia injection pipe;
[0012] Wherein, the end of the arc-shaped ammonia injection pipe furthest from the spiral ammonia injection pipe extends outside the tower body and is connected to the ammonia supply pipe outside the tower; and
[0013] The spiral ammonia injection pipe and the arc-shaped ammonia injection pipe have several ammonia injection holes evenly opened on their pipe walls.
[0014] In one optional embodiment, the tower body includes a plurality of spray chambers and catalyst chambers, the spray chambers and catalyst chambers being arranged at intervals; and,
[0015] The catalyst is located inside the catalyst chamber, and the spiral ammonia injection pipe and the arc-shaped ammonia injection pipe are located inside the spray chamber at the bottom of the tower.
[0016] In one optional embodiment, a second ammonia injection pipe is provided in the spray chamber located between the catalyst chambers. The second ammonia injection pipe is connected to the ammonia supply pipe, and the second ammonia injection pipe and the arc-shaped ammonia injection pipe are arranged in parallel on the ammonia supply pipe.
[0017] In one optional embodiment, an electric heating device is also provided in the spray chamber located between the catalyst chambers, and the electric heating device is symmetrically arranged on the side wall of the tower body.
[0018] In one optional embodiment, the catalyst is a honeycomb-type low-temperature denitrification catalyst or a plate-type low-temperature denitrification catalyst.
[0019] In one optional embodiment, a baffle is provided above the arc-shaped ammonia injection pipe, and the baffle is provided with a plurality of through holes evenly distributed on it.
[0020] In one alternative embodiment, the horizontal extension direction of the arc-shaped ammonia injection pipe is tangent to the outer wall contour of the bottom of the air intake pipe, and the injection direction of the ammonia injection holes on the arc-shaped ammonia injection pipe is perpendicular to the air intake pipe.
[0021] Secondly, embodiments of this disclosure also provide a low-temperature flue gas denitrification device, comprising:
[0022] The tower body has an air outlet pipe at the top and an air inlet pipe on the bottom side wall;
[0023] The tower body is divided into several catalyst chambers and spray chambers, which are arranged at intervals.
[0024] The intake pipe is provided with a premixing structure, which is embedded in the internal flow channel of the intake pipe and is used to inject ammonia gas into the flue gas entering the intake pipe.
[0025] A secondary mixing structure is installed in the spray chamber at the bottom of the tower, which is configured to inject ammonia gas into the premixed flue gas; and,
[0026] Both the premixing structure and the secondary mixing structure are connected to the ammonia supply pipe outside the tower.
[0027] In one optional embodiment, the premixing structure includes a spiral ammonia injection pipe, and the secondary mixing structure includes an arc-shaped ammonia injection pipe;
[0028] One end of the spiral ammonia injection pipe is connected to the arc-shaped ammonia injection pipe, and the other end extends into the air inlet pipe;
[0029] The end of the arc-shaped ammonia injection pipe furthest from the spiral ammonia injection pipe extends outside the tower body and is connected to the ammonia supply pipe outside the tower; and...
[0030] The spiral ammonia injection pipe and the arc-shaped ammonia injection pipe have several ammonia injection holes evenly opened on their pipe walls.
[0031] In one optional embodiment, a second ammonia injection pipe is provided in the spray chamber located between the catalyst chambers. The second ammonia injection pipe is connected to the ammonia supply pipe, and the second ammonia injection pipe and the arc-shaped ammonia injection pipe are arranged in parallel on the ammonia supply pipe.
[0032] The beneficial effect of this utility model is that the low-temperature flue gas denitrification device premixes the flue gas with ammonia in the inlet pipe by setting a spiral ammonia injection pipe in the inlet pipe. The premixed flue gas enters the tower body and continues to be mixed with ammonia injected from the arc-shaped ammonia injection pipe. This ensures that the flue gas and ammonia are fully and evenly mixed before entering the catalyst layer for reaction. This avoids uneven mixing of the denitrification agent (ammonia) with the flue gas, which would lead to incomplete denitrification reaction.
[0033] Other features and advantages of this invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objectives and other advantages of this invention are realized and obtained through the structures particularly pointed out in the description and drawings.
[0034] To make the above-mentioned objectives, features and advantages of this utility model more apparent and understandable, preferred embodiments are described in detail below with reference to the accompanying drawings. Attached Figure Description
[0035] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.
[0036] Figure 1 This is a structural diagram of a low-temperature flue gas denitrification device provided in an embodiment of this disclosure.
[0037] In the picture:
[0038] 100. Tower body; 110. Gas outlet pipe; 120. Gas inlet pipe; 130. Spray chamber; 140. Catalyst chamber; 141. Catalyst; 200. Premixing structure; 210. Spiral ammonia injection pipe; 300. Secondary mixing structure; 310. Arc-shaped ammonia injection pipe; 311. Ammonia injection hole; 400. Ammonia supply pipe; 500. Second ammonia injection pipe; 600. Electric heating device; 700. Baffle. Detailed Implementation
[0039] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.
[0040] In this document, when it is mentioned that a first component is located on a second component, this can mean that the first component can be directly formed on the second component, or that a third component can be inserted between the first and second components. Furthermore, in the accompanying drawings, the thickness of the components may be exaggerated or reduced for the purpose of effectively describing the technical content.
[0041] In this document, when an element or layer is referred to as “located,” “joined to,” “connected to,” “attached to,” or “coupled to” another element or layer, it may be directly located, joined, connected, attached to, or coupled to the other element or layer, or there may be intermediate elements or layers present. Conversely, when an element is referred to as “directly on another element or layer,” “directly joined to,” “directly connected to,” “directly attached to,” or “directly coupled to” another element or layer, there may be no intermediate elements or layers present. Other terms used to describe relationships between elements should be interpreted in a similar manner (e.g., “between” versus “directly between,” “adjacent” versus “directly adjacent,” etc.). As used herein, the term “and / or” includes any and all combinations of one or more of the related listed items.
[0042] In this document, exemplary embodiments of the present disclosure will be described in more detail with reference to the accompanying drawings. As used herein, expressions such as “at least one of…” modify the entire list of elements when following a list of elements, rather than individual elements in the list. For example, the expression “at least one of a, b, and c” should be understood to include only a, only b, only c, both a and b, both a and c, both b and c, or all of a, b, and c.
[0043] The terminology used herein is for the purpose of describing specific exemplary configurations only and is not intended to be limiting. As used herein, the singular articles “a,” “an,” and “the” may also be intended to include plural forms unless otherwise clearly stated herein. The terms “comprising,” “including,” and “having” are inclusive and thus specify the presence of features, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or combinations thereof. The method steps, processes, and operations described herein should not be construed as requiring them to be performed in the specific order discussed or shown, unless specifically identified as such. Additional or alternative steps may be employed.
[0044] As used herein, the phrases “in one embodiment,” “according to one embodiment,” “in some embodiments,” etc., generally refer to the fact that a particular feature, structure, or characteristic following the phrase can be included in at least one embodiment of this disclosure. Therefore, a particular feature, structure, or characteristic can be included in more than one embodiment of this disclosure, such that these phrases do not necessarily refer to the same embodiment. As used herein, the terms “example,” “exemplary,” etc., are used to “serve as an example, instance, or illustration.” Any implementation, aspect, or design described herein as “example” or “exemplary” is not necessarily to be construed as preferred or superior to other implementations, aspects, or designs. Rather, the use of the terms “example,” “exemplary,” etc., is intended to present concepts in a specific manner.
[0045] Research has revealed the following drawbacks of existing technologies: Due to defects in the pipeline design of existing low-temperature denitrification devices, the flue gas and the denitrification agent (ammonia) are not mixed evenly before entering the catalyst layer to react, resulting in insufficient denitrification reaction and poor denitrification effect.
[0046] Based on the above research, this disclosure provides a low-temperature flue gas denitrification device. When the flue gas enters the inlet pipe of the denitrification device, ammonia gas is injected to premix it. The premixed flue gas is then mixed a second time at the bottom of the tower, so that the flue gas is evenly mixed with ammonia gas before entering the catalyst layer, thus solving the above-mentioned problems.
[0047] The shortcomings of the above solutions are the result of the inventor's practical experience and careful research. Therefore, the discovery process of the above problems and the solutions proposed in this disclosure should be considered as the inventor's contribution to this disclosure.
[0048] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.
[0049] The following detailed description, with reference to the accompanying drawings, describes some embodiments of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.
[0050] See Figure 1 This disclosure provides a low-temperature denitrification device for flue gas, including: a tower body 100, with an outlet pipe 110 at the top and an inlet pipe 120 on the bottom side wall. Flue gas is suitable to enter the tower body 100 through the inlet pipe 120, react with the catalyst 141, and then be discharged through the outlet pipe 110.
[0051] See also Figure 1 The bottom of the tower body 100 is equipped with an arc-shaped ammonia injection pipe 310, and a spiral ammonia injection pipe 210 is installed inside the inlet pipe 120. One end of the spiral ammonia injection pipe 210 is connected to the arc-shaped ammonia injection pipe 310, and the other end extends into the inlet pipe 120. The end of the arc-shaped ammonia injection pipe 310 away from the spiral ammonia injection pipe 210 extends outside the tower body 100 and is connected to the external ammonia supply pipe 400. Ammonia gas is transported to the arc-shaped ammonia injection pipe 310 and the spiral ammonia injection pipe 210 through the external ammonia supply pipe 400 (e.g., ...). Figure 1 (As indicated by arrow F1 in the middle). The spiral ammonia injection pipe 210 and the arc-shaped ammonia injection pipe 310 have several ammonia injection holes 311 evenly distributed on their walls. When flue gas enters the inlet pipe 120, the spiral ammonia injection pipe 210 injects ammonia into the flue gas, causing the flue gas and ammonia to premix within the inlet pipe 120. The flue gas, premixed with ammonia, enters the tower body 100, where the arc-shaped ammonia injection pipe 310 injects ammonia a second time, ensuring thorough and uniform mixing before reacting with the catalyst 141 located above the arc-shaped ammonia injection pipe 310. This prevents uneven mixing of the denitrification agent (ammonia) with the flue gas, which could lead to incomplete denitrification.
[0052] See also Figure 1 In some embodiments, the tower body 100 includes several spray chambers 130 and catalyst chambers 140, which are spaced apart. A second ammonia injection pipe 500 is installed in the spray chamber 130 located between the catalyst chambers 140. The second ammonia injection pipe 500 is connected to the ammonia supply pipe 400 and is connected in parallel with an arc-shaped ammonia injection pipe 310 on the ammonia supply pipe 400. A catalyst 141 is installed in the catalyst chamber 140. The spiral ammonia injection pipe 210 and the arc-shaped ammonia injection pipe 310 are located in the spray chamber 130 at the bottom of the tower body 100. With the above arrangement, ammonia can be injected into the flue gas at the bottom and middle of the tower body 100 simultaneously. If the flue gas does not react completely after passing through the first catalyst chamber 140, ammonia is injected into it through the second ammonia injection pipe 500, so that the flue gas can continue to react after entering the second catalyst chamber 140, thereby avoiding incomplete denitrification reaction.
[0053] See also Figure 1In some embodiments, an electric heating device 600 is also provided in the spray chamber 130 located between the catalyst chambers 140. The electric heating device 600 contains heating wires and is symmetrically arranged on the sidewalls of the tower body 100. The temperature of the flue gas may decrease after passing through the first catalyst chamber 140. The electric heating device 600 can heat the flue gas and catalyst 141 within the tower body 100 to maintain the activity of the catalyst 141, thus helping to improve the flue gas denitrification effect.
[0054] See also Figure 1 In some embodiments, catalyst 141 is a honeycomb low-temperature denitrification catalyst 141 or a plate-type low-temperature denitrification catalyst 141.
[0055] See also Figure 1 In some embodiments, a baffle 700 is provided above the arc-shaped ammonia injection pipe 310. The baffle 700 has a plurality of through holes evenly distributed on it. The diameter of the through holes is 10-20 mm and the opening rate is 30%. The baffle 700 can slow down the rising speed of the flue gas, thereby prolonging the mixing time of the flue gas and ammonia.
[0056] See also Figure 1 In some embodiments, the horizontal extension direction of the arc-shaped ammonia injection pipe 310 is tangent to the outer wall contour of the bottom of the intake pipe 120, and the injection direction F2 of the ammonia injection hole 311 on the arc-shaped ammonia injection pipe 310 is perpendicular to the intake pipe 120. The tangential arrangement allows the arc-shaped ammonia injection pipe 310 to perfectly fit the curved surface of the flue, so that the flue gas in the intake pipe 120 flows to the top of the arc-shaped ammonia injection pipe 310; while the vertical injection creates an orthogonal collision between the ammonia jet and the flue gas, so that the flue gas and ammonia are fully mixed.
[0057] See Figure 1 Some embodiments also provide a low-temperature flue gas denitrification device, including: a tower body 100, with an outlet pipe 110 at the top and an inlet pipe 120 on the bottom side wall; the tower body 100 is divided into several catalyst chambers 140 and spray chambers 130, which are spaced apart; wherein, a premixing structure 200 is provided in the inlet pipe 120, which is embedded in the internal flow channel of the inlet pipe 120 for injecting ammonia into the flue gas entering the inlet pipe 120; a secondary mixing structure 300 is provided in the spray chamber 130 at the bottom of the tower body 100, which is configured to inject ammonia into the premixed flue gas; and both the premixing structure 200 and the secondary mixing structure 300 are connected to an external ammonia supply pipe 400.
[0058] See also Figure 1In some embodiments, the premixing structure 200 includes, but is not limited to, a spiral ammonia injection pipe 210, a flow guide plate, or a vortex generator; the secondary mixing structure 300 includes an arc-shaped ammonia injection pipe 310; one end of the spiral ammonia injection pipe 210 is connected to the arc-shaped ammonia injection pipe 310, and the other end extends into the inlet pipe 120; the end of the arc-shaped ammonia injection pipe 310 away from the spiral ammonia injection pipe 210 extends outside the tower body 100 and is connected to the external ammonia supply pipe 400; and the pipe walls of the spiral ammonia injection pipe 210 and the arc-shaped ammonia injection pipe 310 are uniformly provided with a plurality of ammonia injection holes 311. Ammonia gas is transported to the arc-shaped ammonia injection pipe 310 and the spiral ammonia injection pipe 210 through the external ammonia supply pipe 400, and is injected into the flue gas through the ammonia injection holes 311 to achieve mixing of ammonia gas and flue gas.
[0059] In summary, this low-temperature flue gas denitrification device premixes the flue gas with ammonia by installing a spiral ammonia injection pipe 210 inside the inlet pipe 120. The premixed flue gas then enters the tower body 100 and is further mixed with ammonia injected from the arc-shaped ammonia injection pipe 310. This ensures that the flue gas and ammonia are fully and evenly mixed before entering the catalyst layer 141 for reaction. This avoids uneven mixing of the denitrification agent (ammonia) with the flue gas, which could lead to incomplete denitrification reaction.
[0060] In the description of the embodiments of this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.
[0061] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, terms such as "first," "second," and other numerical terms used herein do not imply order or sequence unless expressly indicated herein. Therefore, without departing from the teachings of the exemplary embodiments, the first element, component, region, layer, or segment discussed above may be referred to as the second element, component, region, layer, or segment.
[0062] Spatially relative terms, such as “inside,” “outside,” “below,” “below,” “down,” “above,” “up,” etc., may be used herein to describe the relationship between one element or feature illustrated in the figures and another element or feature. In addition to the orientations depicted in the figures, spatially relative terms may be intended to cover different orientations of the device in use or operation. For example, if the device in the figure is flipped, an element described as “below” or “below” other elements or features would be oriented as “above” other elements or features. Thus, the example term “below” can cover both above and below orientations. The device may be oriented in other ways (rotated 90 degrees or in other orientations), and the spatially relative descriptors used herein are interpreted accordingly.
[0063] In the above discussion, unless otherwise stated, when used to describe numerical values, the terms “about,” “approximately,” “basically,” etc., indicate a change of + / - 10% in that value.
[0064] Based on the above-described preferred embodiments of this utility model, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the technical concept of this utility model. The technical scope of this utility model is not limited to the contents of the specification, but must be determined according to the scope of the claims.
Claims
1. A low-temperature flue gas denitrification device, characterized in that, include: The tower body (100) has an air outlet pipe (110) at the top and an air inlet pipe (120) on the bottom side wall. An arc-shaped ammonia injection pipe (310) is installed at the bottom of the tower body (100); The spiral ammonia injection pipe (210) has one end connected to the arc-shaped ammonia injection pipe (310) and the other end extended into the air inlet pipe (120); The catalyst (141) is positioned above the arc-shaped ammonia injection pipe (310); Wherein, the end of the arc-shaped ammonia injection pipe (310) away from the spiral ammonia injection pipe (210) extends to the outside of the tower body (100) and is connected to the external ammonia supply pipe (400); and, The spiral ammonia injection pipe (210) and the arc-shaped ammonia injection pipe (310) have a number of ammonia injection holes (311) evenly opened on their pipe walls.
2. The low-temperature flue gas denitrification device as described in claim 1, characterized in that, The tower body (100) includes a plurality of spray chambers (130) and catalyst chambers (140), the spray chambers (130) and catalyst chambers (140) being arranged at intervals; and, The catalyst (141) is located in the catalyst chamber (140), and the spiral ammonia spray pipe (210) and the arc-shaped ammonia spray pipe (310) are located in the spray chamber (130) at the bottom of the tower body (100).
3. The low-temperature flue gas denitrification device as described in claim 2, characterized in that, A second ammonia injection pipe (500) is provided in the spray chamber (130) located between the catalyst chambers (140). The second ammonia injection pipe (500) is connected to the ammonia supply pipe (400), and the second ammonia injection pipe (500) and the arc-shaped ammonia injection pipe (310) are arranged in parallel on the ammonia supply pipe (400).
4. The low-temperature flue gas denitrification device as described in claim 2, characterized in that, An electric heating device (600) is also provided in the spray chamber (130) located between the catalyst chambers (140), and the electric heating device (600) is symmetrically arranged on the side wall of the tower body (100).
5. The low-temperature flue gas denitrification device as described in claim 1, characterized in that, The catalyst (141) is a honeycomb low-temperature denitrification catalyst (141) or a plate-type low-temperature denitrification catalyst (141).
6. The low-temperature flue gas denitrification device as described in claim 1, characterized in that, A baffle (700) is provided above the arc-shaped ammonia injection pipe (310), and several through holes are evenly provided on the baffle (700).
7. The low-temperature flue gas denitrification device as described in claim 1, characterized in that, The horizontal extension direction of the arc-shaped ammonia injection pipe (310) is tangent to the outer wall contour of the bottom of the air inlet pipe (120), and the injection direction of the ammonia injection hole (311) on the arc-shaped ammonia injection pipe (310) is perpendicular to the air inlet pipe (120).
8. A low-temperature flue gas denitrification device, characterized in that, include: The tower body (100) has an air outlet pipe (110) at the top and an air inlet pipe (120) on the bottom side wall. The tower body (100) is divided into several catalyst chambers (140) and spray chambers (130), and the spray chambers (130) and catalyst chambers (140) are arranged at intervals; The intake pipe (120) is provided with a premixing structure (200), which is embedded in the internal flow channel of the intake pipe (120) and is used to inject ammonia gas into the flue gas entering the intake pipe (120). A secondary mixing structure (300) is provided in the spray chamber (130) at the bottom of the tower body (100), which is configured to inject ammonia gas into the premixed flue gas; and, Both the premixing structure (200) and the secondary mixing structure (300) are connected to the external ammonia supply pipe (400).
9. The low-temperature flue gas denitrification device as described in claim 8, characterized in that, The premixing structure (200) includes a spiral ammonia injection pipe (210), and the secondary mixing structure (300) includes an arc-shaped ammonia injection pipe (310). One end of the spiral ammonia injection pipe (210) is connected to the arc-shaped ammonia injection pipe (310), and the other end extends into the air inlet pipe (120); The arc-shaped ammonia injection pipe (310) extends away from the spiral ammonia injection pipe (210) to the outside of the tower body (100) and is connected to the external ammonia supply pipe (400); and, The spiral ammonia injection pipe (210) and the arc-shaped ammonia injection pipe (310) have a number of ammonia injection holes (311) evenly opened on their pipe walls.
10. The low-temperature flue gas denitrification device as described in claim 9, characterized in that, A second ammonia injection pipe (500) is provided in the spray chamber (130) located between the catalyst chambers (140). The second ammonia injection pipe (500) is connected to the ammonia supply pipe (400), and the second ammonia injection pipe (500) and the arc-shaped ammonia injection pipe (310) are arranged in parallel on the ammonia supply pipe (400).