Ammonia Fume Mixing Device
By combining the ammonia injection grid module and the impeller device, the problem of uneven ammonia fume mixing was solved, achieving efficient NOx reduction and equipment protection.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- SHAANXI YANCHANG CHINACOAL YULIN ENERGY CHEM
- Filing Date
- 2025-08-25
- Publication Date
- 2026-08-04
AI Technical Summary
In existing SCR denitrification technology, uneven mixing of ammonia and fumes leads to excessive NOx emissions, and excessive ammonia injection causes equipment blockage and reduced efficiency.
The device employs a combination of an ammonia injection grid module, an ammonia nozzle, a primary mixing impeller, and a secondary mixing impeller. Through the stirring of the primary impeller and the further mixing of the secondary impeller, the ammonia and flue gas are ensured to be evenly distributed across the flue gas cross section.
It improves the mixing uniformity of ammonia and flue gas, enhances NOx reduction efficiency, reduces NOx emissions, avoids excessive ammonia injection and equipment blockage, and extends equipment life.
Smart Images
Figure CN224585676U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of flue gas denitrification technology, and in particular to an ammonia-fume mixing device. Background Technology
[0002] As a major consumer of coal, coal-fired power units directly impact air quality through their flue gas emissions. To reduce the pollution caused by flue gas from coal-fired power units, flue gas environmental protection systems have emerged. These systems are typically equipped with multiple environmental protection devices, such as denitrification, dust removal, and desulfurization equipment, aiming to ensure that flue gas meets clean emission requirements before being released, thereby reducing harm to the atmospheric environment.
[0003] In the field of denitrification technology, selective catalytic reduction (SCR) denitrification technology has been widely used in large-scale coal-fired power units due to its mature technology and high denitrification efficiency. SCR denitrification technology utilizes ammonia gas, under the action of a catalyst, to remove nitrogen oxides (NOx) from flue gas. x The ammonia is reduced to nitrogen and water, thus achieving a highly efficient denitrification effect. However, in practical applications, SCR denitrification technology faces the critical problem of uneven ammonia fume mixing.
[0004] Because the flue gas velocity at the SCR ammonia injection grille is relatively high, and the mixing distance between ammonia and flue gas is relatively short, these operating conditions make it difficult for ammonia to fully mix with the flue gas in a short time, leading to frequent uneven ammonia-flue gas mixing. Uneven ammonia-flue gas mixing can cause a series of serious consequences, the most prominent of which is the reduction of NO in the flue gas. x Emissions exceeding standards. Due to insufficient ammonia concentration in some areas, NO in the flue gas cannot be effectively reduced. x This allows NO to be reduced after the flue gas passes through the SCR reactor. x The levels remain high, failing to meet stringent emission standards. Many coal-fired power units are struggling to meet NOx emission requirements. x The emission standards, which use excessive ammonia injection, not only cause ammonia escape but also easily cause blockage of downstream energy-saving and environmental protection equipment, resulting in reduced efficiency and lifespan of the equipment and waste of resources.
[0005] Therefore, how to effectively avoid uneven mixing of ammonia and fumes and reduce NO in flue gas is crucial. x Emissions have become a pressing technical problem that needs to be solved. Utility Model Content
[0006] This application provides an ammonia fume mixing device, which solves the problem of how to effectively avoid uneven mixing of ammonia fume and reduce NO in flue gas. x The issue of emissions.
[0007] This application provides an ammonia-fume mixing device, including an ammonia injection grid module, an ammonia nozzle, a primary mixing impeller, a primary impeller shaft, a secondary mixing large impeller, and a secondary impeller shaft. Each ammonia injection grid module has an independent inlet header, one end of which is connected to an external ammonia supply system, and the other end is connected to an ammonia nozzle, which is horizontally positioned. Each ammonia injection grid module has multiple primary mixing impellers, the axial direction of which is perpendicular to the flue gas flow direction. The primary mixing impellers are mounted on the ammonia injection grid module via the primary impeller shaft and rotate around the primary impeller shaft under the drive of the flue gas. The secondary mixing large impeller is located directly above the ammonia injection grid module, with each secondary mixing large impeller corresponding to one ammonia injection grid module. It is fixed to the flue via the secondary impeller shaft, and the axial direction of the secondary mixing large impeller is the same as the flue gas flow direction, so that it rotates around the secondary impeller shaft under the drive of the flue gas.
[0008] In one possible implementation, the impeller of the primary mixing impeller is positioned close to the ammonia nozzle.
[0009] In one possible implementation, the blades of the primary mixing impeller are in the form of thin metal sheets, made of 316L stainless steel or 2205 duplex stainless steel.
[0010] In one possible implementation, the blades of the secondary mixing impeller are in the form of thin metal sheets, made of 316L stainless steel or 2205 duplex stainless steel.
[0011] In one possible implementation, the number of ammonia injection grille modules is set according to the flue size, and the number of ammonia injection grille modules is 8 or 12.
[0012] The one or more technical solutions provided in this application have at least the following technical effects or advantages: This application achieves efficient mixing of ammonia and flue gas through the synergistic effect of a primary mixing impeller and a secondary mixing impeller. The primary mixing impeller rotates around its shaft under the drive of the flue gas, initially stirring the ammonia sprayed from the ammonia nozzle with the surrounding flue gas, breaking down the stratification between them, and allowing the ammonia to quickly disperse into the flue gas, forming a good mixing state in a small area. The secondary mixing impeller, located directly above the ammonia injection grid module, rotates around its shaft under the action of the flue gas, further stirring and mixing the ammonia and flue gas after the primary mixing over a wider range, further eliminating local uneven areas and ensuring uniform distribution of ammonia and flue gas across the entire flue gas cross-section. Due to the significant improvement in the uniformity of the ammonia-flue gas mixing, ammonia can more fully react with NO in the flue gas. x Through contact, and with the aid of a catalyst, the SCR denitrification reaction proceeds more efficiently. This allows coal-fired power units to achieve higher NO levels. x The removal efficiency has been significantly improved, reducing NO in flue gas. x The content was significantly reduced. This solved the problem of how to effectively avoid uneven mixing of ammonia and fumes, and reduce NO in the flue gas.x The issue of emissions. Attached Figure Description
[0013] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments of this application or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0014] Figure 1 This is a schematic diagram of an ammonia fume mixing device provided in an embodiment of this application;
[0015] Figure 2 A front view of an ammonia fume mixing device provided in an embodiment of this application;
[0016] Figure 3 A left view of an ammonia fume mixing device provided in an embodiment of this application;
[0017] Figure 4 This is a top view of an ammonia fume mixing device provided in an embodiment of this application.
[0018] Icons: 1-Ammonia injection grid module; 2-Ammonia nozzle; 3-First-stage mixing impeller; 4-First-stage impeller shaft; 5-Second-stage mixing large impeller; 6-Second-stage impeller shaft. Detailed Implementation
[0019] In the description of the embodiments of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the embodiments of this application and for 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. Therefore, they should not be construed as limitations on this application. The terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Furthermore, the terms "installed," "connected," and "linked" 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; 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 the embodiments of this application according to the specific circumstances.
[0020] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.
[0021] Figure 1 This is a schematic diagram of an ammonia fume mixing device provided in an embodiment of this application. Figure 1 As shown, the ammonia fume mixing device includes an ammonia injection grid module 1, an ammonia nozzle 2, a primary mixing impeller 3, a primary impeller shaft 4, a secondary mixing large impeller 5, and a secondary impeller shaft 6.
[0022] Figure 2 This is a front view of an ammonia fume mixing device provided in an embodiment of this application. Figure 3 The left view of an ammonia fume mixing device provided in an embodiment of this application. Figure 4 This is a top view of an ammonia fume mixing device provided in an embodiment of this application.
[0023] Each ammonia injection grid module 1 is equipped with an independent inlet header. One end of the inlet header is connected to the external ammonia supply system, and the other end is connected to the ammonia nozzle 2, which is set horizontally.
[0024] Specifically, one end of the inlet header is connected to the external ammonia supply system to ensure a stable and continuous supply of ammonia to the device; the other end is connected to the ammonia nozzle 2, providing a channel for the uniform injection of ammonia. To meet different flue gas operating conditions and ammonia distribution requirements, different models of ammonia nozzles 2 can be selected on the ammonia injection grid modules 1 at different locations. These ammonia nozzles 2 are carefully designed to ensure that ammonia is uniformly injected across the flue gas cross-section, providing good initial conditions for subsequent ammonia-fume mixing.
[0025] Each ammonia injection grid module 1 is equipped with multiple primary mixing impellers 3. The axis of the primary mixing impellers 3 is perpendicular to the flue gas flow direction. The primary mixing impellers 3 are mounted on the ammonia injection grid module 1 through a primary impeller shaft 4 so as to rotate around the primary impeller shaft 4 under the drive of the flue gas.
[0026] Specifically, four primary mixing impellers 3 are typically installed. The blades of the primary mixing impeller 3 are thin metal sheets made of 316L stainless steel or 2205 duplex stainless steel. These two materials have good corrosion resistance and mechanical strength, enabling them to operate stably for a long time in flue gas environments with high temperature, high humidity, and corrosive substances. When the flue gas enters the ammonia injection grid module 1 area, due to the relatively high flue gas velocity at this location, the flue gas exerts a force on the primary mixing impeller 3, causing it to rotate around the primary impeller shaft 4. Simultaneously, the impeller of the primary mixing impeller 3 is positioned close to the ammonia nozzle 2, thus effectively agitating the ammonia gas ejected from the ammonia nozzle 2 with the surrounding flue gas during rotation, enhancing the ammonia-fume mixing effect within the small area.
[0027] The secondary mixing impeller 5 is located directly above the ammonia injection grid module 1. Each secondary mixing impeller 5 corresponds to one ammonia injection grid module 1 and is fixed to the flue via the secondary impeller shaft 6. The axial direction of the secondary mixing impeller 5 is the same as the flue gas flow direction so that it can rotate around the secondary impeller shaft 6 under the drive of the flue gas.
[0028] Specifically, the blades of the secondary mixing impeller 5 are thin metal sheets made of 316L stainless steel or 2205 duplex stainless steel. The flue gas, after primary mixing, then enters the area where the secondary mixing impeller 5 is located. The flue gas exerts a force on the secondary mixing impeller 5, causing it to rotate around the secondary impeller shaft 6. The rotation of the secondary mixing impeller 5 further agitates and mixes the ammonia and flue gas after primary mixing, thereby effectively improving the uniformity of the ammonia-flue gas mixture and ensuring sufficient reaction between the ammonia and flue gas, meeting the requirements of the SCR (Selective Catalytic Reduction) denitrification process.
[0029] In practical applications, the number of ammonia injection grid modules 1 is set according to the flue size, and the number of ammonia injection grid modules 1 is 8 or 12. For example, after installing the ammonia flue gas mixing device of this application in a coal-fired unit, 8 ammonia injection grid modules 1 are set according to the flue size, and 32 primary mixing small impellers 3 are equipped accordingly, that is, 4 primary mixing small impellers 3 on each ammonia injection grid module 1, and 8 secondary mixing large impellers 5, that is, 1 secondary mixing large impeller 5 on the top of each ammonia injection grid module 1.
[0030] During normal operation, the flue gas enters the SCR and first flows through the ammonia injection grid module 1 area. At this time, the external ammonia supply system delivers ammonia through the inlet header to the ammonia nozzle 2, which then evenly injects the ammonia into the flue. Due to the relatively high flue gas velocity at this location, the flue gas exerts a force on the primary mixing impeller 3, causing it to rotate around the primary impeller shaft 4. During this rotation, the blades of the primary mixing impeller 3 agitate the ammonia ejected from the special ammonia nozzle 2 with the surrounding flue gas, ensuring thorough mixing within a small area to form a preliminary ammonia-flue gas mixture. The flue gas after primary mixing then enters the secondary mixing large impeller 5 area. The flue gas exerts a force on the secondary mixing large impeller 5, causing it to rotate around the secondary impeller shaft 6. The rotation of the secondary mixing impeller 5 further agitates and mixes the ammonia and flue gas after the primary mixing. Through the rotation of the blades, the ammonia and flue gas are more evenly distributed, thereby effectively improving the uniformity of ammonia-flue gas mixing, ensuring that ammonia and flue gas react fully, meeting the requirements of SCR (Selective Catalytic Reduction) denitrification process, achieving efficient ammonia-flue gas mixing, avoiding excessive ammonia injection, effectively extending the service life of downstream energy-saving and environmental protection equipment, maintaining its operating efficiency, and meeting the deep energy-saving and environmental protection needs in the field of flue gas denitrification of coal-fired units.
[0031] The various embodiments in this specification are described in a progressive manner. For the same or similar parts between the various embodiments, please refer to each other. Each embodiment focuses on describing the differences from other embodiments.
[0032] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit this application. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of this application.
Claims
1. An ammonia fume mixing device, characterized in that, It includes an ammonia injection grid module (1), an ammonia nozzle (2), a primary mixing impeller (3), a primary impeller shaft (4), a secondary mixing large impeller (5), and a secondary impeller shaft (6); Each ammonia injection grid module (1) is equipped with an independent inlet header pipe. One end of the inlet header pipe is connected to the external ammonia supply system, and the other end is connected to the ammonia nozzle (2). The ammonia nozzle (2) is set horizontally. Each ammonia injection grid module (1) is equipped with multiple primary mixing impellers (3). The primary mixing impellers (3) are axially perpendicular to the flue gas flow direction. The primary mixing impellers (3) are mounted on the ammonia injection grid module (1) via a primary impeller shaft (4) so as to rotate around the primary impeller shaft (4) under the drive of the flue gas. The secondary mixing impeller (5) is located directly above the ammonia injection grid module (1). Each secondary mixing impeller (5) corresponds to one ammonia injection grid module (1) and is fixed to the flue via the secondary impeller shaft (6). The axial direction of the secondary mixing impeller (5) is the same as the flue gas flow direction so that it can rotate around the secondary impeller shaft (6) under the drive of the flue gas.
2. The ammonia fume mixing device according to claim 1, characterized in that, The impeller of the primary mixing impeller (3) is located close to the ammonia nozzle (2).
3. The ammonia fume mixing device according to claim 1, characterized in that, The blades of the primary mixing impeller (3) are thin metal sheets made of 316L stainless steel or 2205 duplex stainless steel.
4. The ammonia fume mixing device according to claim 1, characterized in that, The blades of the secondary mixing impeller (5) are thin metal sheets made of 316L stainless steel or 2205 duplex stainless steel.
5. The ammonia fume mixing device according to claim 1, characterized in that, The number of ammonia injection grille modules (1) is set according to the flue size, and the number of ammonia injection grille modules (1) is 8 or 12.