Ammonia smoke mixing device for accurately spraying ammonia
By introducing a resistance self-balancing module, a self-cleaning nozzle, and a turbulent mixing module into the ammonia-fume mixing device, the problems of ammonia escape and equipment blockage caused by excessively high ammonia-nitrogen molar ratio were solved, achieving uniform mixing and self-cleaning of ammonia and flue gas, and improving the operational stability and efficiency of the device.
Patent Information
- Application Number
- CN202422605459.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-28
- Publication Date
- 2025-11-14
- Estimated Expiration
- 2034-10-28
AI Technical Summary
Existing ammonia-nitrogen mixing devices are prone to problems such as excessively high ammonia-nitrogen molar ratios in certain areas, leading to excessive ammonia injection into the catalyst channels, excessive ammonia escape, and equipment blockage.
The system employs a resistance self-balancing module, a self-cleaning nozzle, and a turbulence mixing module, including an ammonia injection grid, a self-cleaning nozzle, and turbulence blades. It is designed as a branch-type pipeline structure, combined with a flow regulating valve and an ammonia concentration monitoring and feedback module, to achieve uniform mixing and self-cleaning of ammonia and flue gas.
It improves the mixing efficiency of ammonia and flue gas, reduces the risk of ammonia escape, ensures stable operation of the unit, reduces maintenance costs, and meets the needs of precise ammonia injection.
Smart Images
Figure CN223542762U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of air pollutant control, and in particular to an ammonia fume mixing device for precise ammonia injection. Background Technology
[0002] The ammonia fume mixing device is one of the key pieces of equipment for precise ammonia injection in the denitrification system. Its injection structure and type directly affect the distribution of the ammonia-nitrogen molar ratio at the catalyst inlet, thereby affecting the denitrification efficiency and ammonia slip.
[0003] Based on their different forms, ammonia fume mixing devices are mainly classified into grid-type ammonia fume mixing devices, mixed-type ammonia fume mixing devices, and vortex-type ammonia fume mixing devices. Grid-type ammonia fume mixing devices have low mixing intensity and are suitable for units with long mixing distances. Turbulent-type ammonia fume mixing devices, while having good mixing effects, lack zoning or have few zoning sections along their length, making them unsuitable for fine-tuning and suitable for units with relatively uniform velocity distribution before the ammonia fume mixing device. Mixed-type ammonia fume mixing devices combine the advantages of both types, but their complex structure often leads to their use in units with high inlet NOx concentrations or high denitrification efficiency.
[0004] To achieve the ultra-low emission standard of SCR denitrification efficiency of over 90%, the average ammonia-nitrogen molar ratio at the catalyst inlet is designed to be above 0.95. If the ammonia-fume mixing device is inadequate, the ammonia-nitrogen molar ratio may locally exceed 1, resulting in excessive ammonia injection within the catalyst channels. This leads to excessive ammonia escape and subsequent equipment blockage. Utility Model Content
[0005] This application addresses the problem of insufficient performance of ammonia fume mixing devices, where the ammonia-nitrogen molar ratio is often excessive in certain areas, resulting in excessive ammonia injection in some catalyst channels, leading to excessive ammonia escape and subsequent equipment blockage. It provides an ammonia fume mixing device for precise ammonia injection, comprising: a resistance self-balancing module, a self-cleaning nozzle, and a turbulence mixing module.
[0006] The resistance self-balancing module includes an ammonia injection grid, which is connected to the ammonia main pipe. Multiple self-cleaning nozzles are evenly distributed on the ammonia injection grid. One end of each self-cleaning nozzle is fixedly connected to and connected to the ammonia injection grid, and the other end of each self-cleaning nozzle extends away from the ammonia injection grid, with the nozzle opening facing downwards.
[0007] The ammonia injection grid is also provided with the turbulence mixing module, which includes: a turbulence shaft and turbulence blades;
[0008] The number of the turbulence blades is at least 10 pieces, which are fixed to one end of the turbulence shaft in a ring array. The turbulence blades are perpendicular to the flue axial direction. The other end of the turbulence shaft is rotatably connected to the ammonia injection grid and is located below the self-cleaning nozzle.
[0009] The position of the turbulence blades on the turbulence shaft is higher than the opening position of the self-cleaning nozzle.
[0010] In one feasible implementation, the self-cleaning nozzles are arranged in two rows on the ammonia injection grid, with the two rows of self-cleaning nozzles distributed on both sides of the ammonia injection grid and staggered.
[0011] In one feasible implementation, the jet direction of the self-cleaning nozzle makes an angle greater than or equal to 0° with the axial direction of the flue.
[0012] In one feasible implementation, the self-cleaning nozzle includes a pulse cleaning device, which includes a pulse valve and a compressed air source, wherein the pulse valve is connected to the compressed air source.
[0013] The pulse cleaning device is used to periodically perform pulse cleaning on the self-cleaning nozzle to remove the accumulated dust inside and around the self-cleaning nozzle.
[0014] In one feasible implementation, the resistance self-balancing module further includes: a main pipe and branch pipes;
[0015] The main pipe is T-shaped and includes a first end, a second end, and a third end. The first end and the second end are symmetrical, and the third end is connected to the main ammonia pipe.
[0016] There are two branch pipes, which are respectively connected to the first end of the main pipe and the second end of the main pipe, and the two branch pipes are distributed opposite each other;
[0017] The ammonia injection grid is fixed to the branch pipe and is connected to the branch pipe.
[0018] In one feasible implementation, the branch pipe is T-shaped and includes: a first end, a second end, and a third end. The first end and the second end are symmetrical, and the third end is connected to the first end or the second end of the main pipe.
[0019] There are four ammonia injection grilles, which are respectively connected to the first end and the second end of the two branch pipes, and the two ammonia injection grilles on each branch pipe are arranged opposite each other.
[0020] In one feasible implementation, a flow regulating valve is provided at the connection between the main pipe and the branch pipe, as well as at the connection between the branch pipe and the ammonia injection grid.
[0021] The flow regulating valve is used to regulate the flow rate of ammonia gas through each pipeline;
[0022] The flow regulating valve is adjusted manually and / or automatically according to the nitrogen oxide concentration and ammonia slip parameters in the flue gas.
[0023] In one feasible implementation, an ammonia concentration monitoring and feedback module is also included. The ammonia concentration monitoring and feedback module includes an ammonia concentration monitoring sensor and a controller. The controller is communicatively connected to both the flow regulating valve and the ammonia concentration monitoring sensor.
[0024] The ammonia concentration monitoring sensor is used to monitor the ammonia concentration in the flue and compare it with a preset value to obtain a comparison result, and feed the comparison result back to the controller. The controller is used to adjust the ammonia supply according to the comparison result.
[0025] In one feasible implementation, a flue gas preheating device is also included, which is positioned above the ammonia injection grid and is used to preheat the flue gas entering the flue.
[0026] This application provides an ammonia-fume mixing device for precise ammonia injection. Changing the nozzle angle improves the ammonia-nitrogen mixing effect. Reducing the nozzle diameter and increasing the number of nozzles in the ammonia-fume mixing device facilitates uniform mixing of ammonia and flue gas. A branch-type pipeline layout structure is adopted, using geometric symmetry to eliminate header effects and achieve resistance self-balancing. A turbulent mixing nozzle structure is used, forming stable vortices or swirls, which enhances gas turbulence and strengthens the diffusion effect of turbulence. This application couples the ammonia injection grid and the surrounding blades together, allowing dust particles to bypass the nozzles, eliminating nozzle clogging problems and ensuring stable operation of the ammonia injection grid. This application improves the uniformity of flue gas distribution and ammonia concentration distribution in the SCR system by optimizing the design of the ammonia-fume mixing device. Attached Figure Description
[0027] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present invention and, together with the description, serve to explain the principles of the embodiments of the present invention. Obviously, the drawings described below are merely some embodiments of the present invention, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.
[0028] Figure 1This is a schematic diagram of the structure of an ammonia fume mixing device for precise ammonia injection, as exemplarily shown in an embodiment of this application.
[0029] Figure 2 yes Figure 1 Top view.
[0030] Attached image captions:
[0031] 1-Resistance self-balancing module; 2-Self-cleaning nozzle; 3-Turbulent mixing module; 11-Main pipe; 12-Branch pipe; 13-Ammonia injection grid; 111-Main pipe first end; 112-Main pipe second end; 113-Main pipe third end; 121-Branch pipe first end; 122-Branch pipe second end; 123-Branch pipe third end. Detailed Implementation
[0032] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided to make the present invention more comprehensive and complete, and to fully convey the concept of the exemplary embodiments to those skilled in the art. The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to give a full understanding of the implementation of embodiments of the present invention.
[0033] The ammonia-fume mixing device is crucial for the precise ammonia injection in a denitrification system. Its form affects the ammonia-nitrogen molar ratio distribution at the catalyst inlet, thus influencing denitrification efficiency and ammonia slip. The main types are grid-type, turbulent-flow type, and mixed type, but each has its limitations: grid-type has low mixing intensity, turbulent-flow type has few zones and cannot meet fine-tuning requirements, and mixed type has a complex structure.
[0034] To achieve ultra-low emission standards with SCR denitrification efficiency exceeding 90%, the average ammonia-nitrogen molar ratio at the catalyst inlet needs to be designed to be above 0.95. However, when the performance of the ammonia-fume mixing unit is insufficient, the local ammonia-nitrogen molar ratio is prone to exceed the standard, leading to ammonia escape and blockage of downstream equipment.
[0035] With increasingly stringent emission standards, zoned controlled, high-efficiency, and precise ammonia injection has become mainstream. However, a current problem is that, despite upgrades to zoned ammonia injection technology, the flue gas flow field at the reactor inlet and the ammonia injection pattern still jointly determine the uniformity of the ammonia-to-nitrogen ratio, while flow field optimization after the ammonia-flue gas mixing device has little impact on this. Therefore, how to further optimize the coupling between the zoned controlled ammonia-flue gas mixing device and the uniform process to achieve more uniform ammonia injection has become an urgent problem to be solved.
[0036] To solve the above problems, refer to Figure 1 and Figure 2As shown, this application provides an ammonia-fume mixing device for precise ammonia injection, including: a resistance self-balancing module 1, a self-cleaning nozzle 2, and a turbulence mixing module 3; aiming to achieve efficient and uniform mixing of ammonia and flue gas, while ensuring the stability and reliability of the device operation.
[0037] The resistance self-balancing module 1 includes an ammonia injection grille 13, which is tightly connected to the main ammonia pipe to ensure a stable supply of ammonia. Multiple self-cleaning nozzles 2, evenly spaced on the grille, achieve uniform ammonia spraying, avoiding problems of excessively high or low ammonia concentrations in certain areas. This design not only improves the utilization efficiency of ammonia but also reduces the environmental pollution risk caused by uneven ammonia distribution.
[0038] One end of the self-cleaning nozzle 2 is fixedly connected to the ammonia injection grille 13 and kept unobstructed, ensuring a continuous supply of ammonia gas; the other end extends away from the ammonia injection grille 13 with its opening facing downwards. This design helps ammonia gas to penetrate and diffuse better into the flue gas. Secondly, the self-cleaning nozzle 2 has a certain self-cleaning function, which can effectively prevent nozzle blockage caused by dust or coking accumulated during long-term operation, ensuring the continuous and efficient operation of the device.
[0039] To further improve the mixing efficiency of ammonia and flue gas, this device also includes a turbulence mixing module 3. The turbulence mixing module 3 consists of a turbulence shaft and at least three turbulence blades. The turbulence blades are fixed in a ring array at one end of the turbulence shaft and perpendicular to the flue duct axis. This arrangement not only increases the turbulence of the flue gas flow but also promotes sufficient contact and mixing between ammonia and flue gas. The other end of the turbulence shaft is mounted on the ammonia injection grid 13 via a rotary connection and positioned below the self-cleaning nozzle 2, ensuring that the turbulence effect is synchronized with the ammonia spraying. Notably, the position of the turbulence blades is carefully designed to be higher than the opening of the self-cleaning nozzle 2. This height difference allows the turbulence effect to more effectively guide the ammonia downwards, further enhancing the mixing effect. By coupling the positions of the ammonia injection grid 13 and the turbulence blades together, this device ensures that dust particles bypass the self-cleaning nozzle 2, eliminating the clogging problem of the self-cleaning nozzle 2 and thus ensuring the stable operation of the ammonia injection grid 13.
[0040] As can be seen from the above embodiments, the ammonia-fume mixing device of this application achieves uniform ammonia spraying, self-cleaning, and efficient turbulent mixing of flue gas, significantly improving the mixing efficiency of ammonia and flue gas, reducing the risk of environmental pollution, and ensuring the long-term stable operation of the device. This innovative design not only meets the needs of precise ammonia injection but also provides new ideas for technological advancements in the field of flue gas denitrification.
[0041] In some embodiments of this application, the self-cleaning nozzles 2 are provided in two rows on the ammonia injection grid 13, and the two rows of self-cleaning nozzles 2 are distributed on both sides of the ammonia injection grid 13, and the two rows of self-cleaning nozzles 2 are staggered.
[0042] In the ammonia fume mixing device of this embodiment, the self-cleaning nozzles 2 are arranged in two rows on the ammonia injection grid 13. These two rows of nozzles are located on both sides of the ammonia injection grid 13, forming a symmetrical and efficient spraying layout. This symmetrical design ensures that ammonia gas can be sprayed evenly from both sides of the flue. This layout helps to avoid excessive concentration of ammonia gas on one side, thereby ensuring the uniform distribution of ammonia gas across the entire flue cross-section. In addition, the symmetrical layout also helps to reduce the corrosion or ash accumulation on the inner wall of the flue caused by uneven ammonia gas spraying, extending the service life of the device.
[0043] Furthermore, a staggered distribution design is adopted between the two rows of self-cleaning nozzles 2. This means that the spray points of each row of self-cleaning nozzles 2 do not completely overlap with the spray points of the other row, but rather form a certain overlap. This staggered distribution design further enhances the diffusion effect of ammonia, allowing it to mix more thoroughly with the flue gas. The staggered distribution also significantly reduces the spray blind zone between adjacent self-cleaning nozzles 2, thereby ensuring that ammonia is covered without dead angles throughout the entire flue.
[0044] More importantly, the staggered two-row design of the self-cleaning nozzles 2 not only improves the mixing efficiency of ammonia but also enhances the self-cleaning capability of the device. Due to the staggered arrangement of the self-cleaning nozzles 2, when dust or coke accumulates on one self-cleaning nozzle 2 due to long-term operation, the spraying action of the adjacent self-cleaning nozzles 2 helps to remove these accumulations, thereby extending the cleaning cycle of the self-cleaning nozzles 2 and reducing maintenance costs.
[0045] In some embodiments of this application, the jet direction of the self-cleaning nozzle 2 forms an angle greater than or equal to 30° with the axial direction of the flue. This large angle allows the ejected ammonia gas to penetrate the flue gas layer at an inclined angle. This inclined jet not only increases the contact area between the ammonia gas and the flue gas but also promotes turbulent mixing between them. Compared to jetting perpendicular or parallel to the flue gas axis, inclined jetting can more effectively break the laminar flow of the flue gas, forming more eddies and turbulence, thereby accelerating the mixing process of ammonia gas and flue gas.
[0046] The inclined injection design also allows ammonia to be distributed more evenly in the flue gas, reducing localized accumulation and waste. Because the ammonia is mixed more thoroughly with the flue gas, its utilization efficiency is significantly improved. This not only helps reduce ammonia consumption but also reduces the environmental pollution risks caused by excess ammonia.
[0047] The design of the tilted self-cleaning nozzle 2 also allows it to better adapt to changes in flue gas velocity. When the flue gas velocity increases, the tilted ammonia gas can mix better with the high-speed flue gas; while when the flue gas velocity decreases, the tilted ammonia gas can penetrate deeper into the flue gas, ensuring a stable mixing effect.
[0048] In some embodiments of this application, a pulse cleaning device is integrated inside the self-cleaning nozzle 2. This device mainly consists of a pulse valve and a compressed air source. The pulse valve, as a control element, is responsible for precisely controlling the timing and duration of compressed air release; while the compressed air source provides the high-pressure gas required for cleaning. The pulse valve and the compressed air source are tightly connected through a pipeline to ensure that high-pressure gas can be quickly and effectively injected into and around the nozzle when needed.
[0049] The pulse jet cleaning device operates on the principle of the strong impact force generated by the instantaneous release of high-pressure gas. When a certain amount of dust accumulates inside or around the self-cleaning nozzle 2, the pulse valve opens at a preset time interval, allowing high-pressure gas from the compressed air source to rapidly pass through the self-cleaning nozzle 2 and be ejected outwards. This instantaneous release of high-pressure gas generates a strong shock wave, effectively flushing away the accumulated dust inside and around the self-cleaning nozzle 2.
[0050] The pulse cleaning device periodically cleans the self-cleaning nozzle 2, ensuring that the inside and surrounding area of the nozzle 2 remain clean. This efficient cleaning method not only extends the nozzle's service life but also improves the spraying efficiency and mixing effect of ammonia. Because the pulse cleaning device performs cleaning automatically and periodically, it significantly reduces downtime caused by clogging of the self-cleaning nozzle 2. This not only improves the operating efficiency of the device but also reduces maintenance costs.
[0051] The pulse cleaning device is designed to adapt to cleaning needs under different working conditions. By adjusting the opening frequency and duration of the pulse valve, precise control of the cleaning intensity can be achieved, ensuring that the self-cleaning nozzle 2 maintains good working condition under various conditions. Simultaneously, the pulse cleaning device uses compressed air as the cleaning medium, which is not only environmentally friendly and pollution-free but also saves water resources to a certain extent. Compared with traditional water cleaning methods, pulse cleaning is more energy-efficient and effective.
[0052] In some embodiments of this application, the resistance self-balancing module 1 further includes: a main pipe 11 and branch pipes 12. The main pipe 11 is T-shaped and includes: a first end 111, a second end 112, and a third end 113. The first end 111 and the second end 112 are symmetrical, and the third end 113 is connected to the ammonia main pipe. There are two branch pipes 12, which are respectively connected to the first end 111 and the second end 112 of the main pipe, and the two branch pipes 12 are distributed opposite each other. The ammonia spraying grid 13 is fixed on the branch pipes 12 and is connected to the branch pipes 12.
[0053] Furthermore, the branch pipe 12 is T-shaped and includes: a first end 121, a second end 122, and a third end 123. The first end 121 and the second end 122 are symmetrical, and the third end 123 is connected to the first end 111 or the second end 112 of the main pipe. There are four ammonia injection grilles 13, which are respectively connected to the first end 121 and the second end 122 of two branch pipes 12, and the two ammonia injection grilles 13 on each branch pipe 12 are arranged opposite each other.
[0054] Specifically, the main pipe 11 adopts a T-shaped design, which allows it to connect both the main ammonia pipe and the two branch pipes 12 simultaneously, achieving effective ammonia distribution. This design ensures a more balanced flow of ammonia within the main pipe 11, avoiding increased resistance caused by excessive flow on one side. The third end 113 of the main pipe is connected to the main ammonia pipe, serving as the inlet for ammonia to enter the main pipe, ensuring a stable supply of ammonia.
[0055] Branch pipe 12 also adopts a T-shaped design, which can further refine the distribution of ammonia gas, ensuring that each ammonia injection grid 13 receives a sufficient and uniform supply of ammonia gas. Each branch pipe can supply ammonia gas to two ammonia injection grids, further ensuring the uniform distribution of ammonia gas. At the same time, the two ammonia injection grids 13 on each branch pipe 12 are symmetrically distributed. This layout not only improves the ammonia spraying efficiency but also reduces the risk of dust accumulation or blockage caused by uneven spraying.
[0056] It is understood that the resistance self-balancing module 1 of this application adopts a branching pipeline layout structure, which is similar to a tree branch in nature. The main pipeline is like the trunk, and the branch pipelines are like the branches, gradually differentiating until the end. The branching pipeline layout structure adopted in this embodiment can eliminate the header effect and resistance self-balancing based on the symmetry of the geometric structure. Branch pipelines can be added, removed, or adjusted according to actual needs. This flexibility allows the system to adapt to ammonia transportation needs of different scales, and branch pipelines can be added or removed as needed to meet the needs of device expansion or reduction.
[0057] In some embodiments of this application, flow regulating valves are provided at the connection between the main pipe 11 and the branch pipe 12, as well as at the connection between the branch pipe 12 and the ammonia injection grille 13. The flow regulating valves are used to regulate the ammonia flow rate through each pipe. The flow regulating valves are adjusted manually and / or automatically according to the nitrogen oxide concentration parameters and ammonia escape parameters in the flue gas.
[0058] The flow regulating valve at the junction of the main pipe 11 and the branch pipe 12 precisely controls the ammonia flow from the main pipe to each branch pipe, ensuring that each branch pipe 12 receives the amount of ammonia that matches its needs. This design not only avoids excessive or insufficient ammonia distribution but also ensures the overall stability and efficiency of the system.
[0059] At the interface between branch pipe 12 and ammonia injection grille 13, a flow regulating valve further refines the distribution of ammonia gas, precisely adjusting the ammonia flow rate to each injection point according to the actual needs of the ammonia injection grille 13. This refined flow control allows ammonia gas to be sprayed evenly and efficiently into the flue gas, thereby greatly improving the utilization rate of ammonia gas and the denitrification effect.
[0060] The flow control valve supports manual adjustment, allowing operators to adjust the flow rate by rotating the valve handle according to actual site conditions. This adjustment method is simple and intuitive, suitable for scenarios requiring rapid response or temporary flow adjustments. Secondly, the flow control valve also supports automatic adjustment, capable of receiving real-time nitrogen oxide concentration and ammonia slip parameters from the flue gas monitoring system and automatically adjusting the flow rate accordingly. When the nitrogen oxide concentration in the flue gas increases, the flow control valve automatically increases the ammonia flow rate to improve denitrification efficiency; conversely, when the ammonia slip is too high, it reduces the ammonia flow rate to reduce environmental pollution.
[0061] In some embodiments of this application, an ammonia concentration monitoring and feedback module is also included. This module includes an ammonia concentration monitoring sensor and a controller. The controller is communicatively connected to both the flow regulating valve and the ammonia concentration monitoring sensor. The ammonia concentration monitoring sensor monitors the ammonia concentration in the flue and compares it with a preset value to obtain a comparison result. The comparison result is then fed back to the controller, which adjusts the ammonia supply based on the comparison result.
[0062] The ammonia concentration monitoring sensor is used to monitor the ammonia concentration in the flue in real time. It can quickly capture minute changes in ammonia in the flue and convert them into electrical signals for transmission. By using a preset ammonia concentration threshold, the ammonia concentration monitoring sensor can automatically compare the real-time monitored value with the preset value and obtain the comparison result.
[0063] The controller is responsible for receiving feedback from the ammonia concentration monitoring sensor, analyzing and comparing the results, and making corresponding adjustment decisions. The controller has established stable communication connections with both the flow control valve and the ammonia concentration monitoring sensor, ensuring real-time information transmission and processing. When it receives the comparison results from the sensor, the controller immediately analyzes and judges the data. If the current ammonia concentration is higher than the preset value, the controller sends a command to the flow control valve to reduce the ammonia supply to prevent ammonia escape; conversely, if the ammonia concentration is lower than the preset value, it increases the ammonia supply to ensure optimal denitrification performance.
[0064] In some embodiments of this application, a flue gas preheating device is also included. The flue gas preheating device is located above the ammonia injection grid 13 and is used to preheat the flue gas entering the flue.
[0065] A flue gas preheating device typically consists of a preheater body, heating elements, and a control system. The preheater body, serving as the flue gas passage, is designed to fully consider the flow characteristics and preheating requirements of the flue gas, ensuring its uniform and efficient passage. The heating elements provide the necessary heat for preheating, typically employing electric heating, steam heating, or hot flue gas recirculation, the specific choice depending on the system's actual conditions and preheating needs. The control system monitors and controls the preheating process, ensuring the stability and accuracy of the preheating temperature.
[0066] The main function of the flue gas preheating device is to preheat the flue gas entering the flue, bringing its temperature to the optimal range required for the denitrification reaction. Through preheating, the flue gas temperature is increased, thereby accelerating the chemical reaction rate between ammonia and nitrogen oxides and improving denitrification efficiency. The preheated flue gas not only has a suitable temperature but also more stable physical and chemical properties, which is conducive to the thorough mixing and reaction of ammonia and nitrogen oxides. This further optimizes the denitrification environment, making the denitrification process more efficient and stable.
[0067] As described above, this application provides an ammonia-fume mixing device for precise ammonia injection. Changing the nozzle angle improves the ammonia-nitrogen mixing effect, while reducing the nozzle diameter and increasing the number of nozzles facilitates uniform mixing of ammonia and flue gas. A branch-type pipeline layout is adopted, using geometric symmetry to eliminate header effects and achieve resistance self-balancing. A turbulent mixing nozzle structure is used, where the ammonia and nitrogen oxide mixture, under the action of the turbulent blades, forms stable vortices or swirls, enhancing gas turbulence, strengthening the diffusion effect of turbulence, and saving space. Furthermore, the turbulent blades effectively reform the incoming flue gas, further improving the uniformity of the flue gas velocity, thus laying the foundation for thorough ammonia-nitrogen mixing. This application couples the ammonia injection grid and the surrounding blades together, allowing dust particles to bypass the nozzles, eliminating nozzle clogging and ensuring stable operation of the ammonia injection grid. Furthermore, in the swirling zone below the turbulence vanes, when ammonia gas exits the nozzle, a strong turbulent effect occurs below the vanes, causing the ammonia gas to diffuse rapidly under the influence of turbulent kinetic energy. This significantly enhances the space and time for ammonia-nitrogen mixing. This application improves the uniformity of flue gas distribution and ammonia concentration distribution in the SCR system by optimizing the design of the ammonia-fume mixing device.
[0068] Other embodiments of this disclosure will readily occur to those skilled in the art upon consideration of the disclosure in the specification and the embodiments. This application is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not disclosed herein.
Claims
1. An ammonia fume mixing device for precise ammonia injection, characterized in that, include: Resistance self-balancing module (1), self-cleaning nozzle (2), and turbulence mixing module (3); The resistance self-balancing module (1) includes an ammonia injection grid (13), which is connected to the ammonia main pipe. Multiple self-cleaning nozzles (2) are evenly distributed on the ammonia injection grid (13). One end of the self-cleaning nozzle (2) is fixedly connected to the ammonia injection grid (13) and is connected to the ammonia injection grid (13). The other end of the self-cleaning nozzle (2) extends away from the ammonia injection grid (13), and the opening of the self-cleaning nozzle (2) is downward. The ammonia injection grid (13) is also provided with the turbulence mixing module (3), which includes: a turbulence shaft and turbulence blades; The number of the turbulence blades is at least 3, which are fixed in a ring array at one end of the turbulence shaft. The turbulence blades are perpendicular to the flue axis. The other end of the turbulence shaft is rotatably connected to the ammonia injection grid (13) and is located below the self-cleaning nozzle (2). The position of the turbulence blades on the turbulence shaft is higher than the opening position of the self-cleaning nozzle (2).
2. The ammonia fume mixing device for precise ammonia injection according to claim 1, characterized in that, The self-cleaning nozzles (2) are arranged in two rows on the ammonia spraying grid (13). The two rows of self-cleaning nozzles (2) are distributed on both sides of the ammonia spraying grid (13), and the two rows of self-cleaning nozzles (2) are staggered.
3. The ammonia fume mixing device for precise ammonia injection according to claim 1, characterized in that, The jet direction of the self-cleaning nozzle (2) is at an angle greater than or equal to 30° with the axial direction of the flue.
4. The ammonia fume mixing device for precise ammonia injection according to claim 1, characterized in that, The self-cleaning nozzle (2) includes a pulse cleaning device, which includes a pulse valve and a compressed air source, and the pulse valve is connected to the compressed air source. The pulse cleaning device is used to periodically perform pulse cleaning on the self-cleaning nozzle (2) to remove the accumulated dust inside and around the self-cleaning nozzle (2).
5. An ammonia fume mixing device for precise ammonia injection according to claim 1, characterized in that, The resistance self-balancing module (1) also includes: a main pipe (11) and a branch pipe (12); The main pipe (11) is T-shaped and includes: a first end (111), a second end (112) and a third end (113). The first end (111) and the second end (112) are symmetrical, and the third end (113) is connected to the main ammonia pipe. There are two branch pipes (12), which are respectively connected to the first end (111) of the main pipe and the second end (112) of the main pipe, and the two branch pipes (12) are arranged opposite each other; The ammonia spraying grid (13) is fixed on the branch pipe (12) and is connected to the branch pipe (12).
6. An ammonia fume mixing device for precise ammonia injection according to claim 5, characterized in that, The branch pipe (12) is T-shaped and includes: a first end (121), a second end (122) and a third end (123). The first end (121) and the second end (122) are symmetrical, and the third end (123) is connected to the first end (111) or the second end (112) of the main pipe. There are four ammonia spraying grids (13), which are respectively connected to the first end (121) and the second end (122) of the two branch pipes (12), and the two ammonia spraying grids (13) on each branch pipe (12) are arranged opposite each other.
7. An ammonia fume mixing device for precise ammonia injection according to claim 5 or 6, characterized in that, A flow regulating valve is provided at the connection between the main pipe (11) and the branch pipe (12) and at the connection between the branch pipe (12) and the ammonia injection grid (13); The flow regulating valve is used to regulate the flow rate of ammonia gas through each pipeline; The flow regulating valve is adjusted manually and / or automatically according to the nitrogen oxide concentration and ammonia slip parameters in the flue gas.
8. An ammonia fume mixing device for precise ammonia injection according to claim 7, characterized in that, It also includes an ammonia concentration monitoring and feedback module, which includes an ammonia concentration monitoring sensor and a controller. The controller is connected to both the flow regulating valve and the ammonia concentration monitoring sensor. The ammonia concentration monitoring sensor is used to monitor the ammonia concentration in the flue and compare it with a preset value to obtain a comparison result, and feed the comparison result back to the controller. The controller is used to adjust the ammonia supply according to the comparison result.
9. An ammonia fume mixing device for precise ammonia injection according to claim 1, characterized in that, It also includes a flue gas preheating device, which is positioned above the ammonia injection grid (13) and is used to preheat the flue gas entering the flue.