A pipeline type urea mixing device
By using an open spiral plate to create a swirling flow in the urea mixing device, the urea droplets fully contact and break down through the through holes, thus solving the problem of urea crystallization blockage and improving the decomposition efficiency and mixing effect of urea.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- WEICHAI POWER CO LTD
- Filing Date
- 2025-07-25
- Publication Date
- 2026-07-10
AI Technical Summary
In existing technologies, urea tends to deposit on the surface of the mixing orifice plate during waste gas treatment, forming large droplets and crystallizing, leading to blockage, difficulty in effective decomposition, and increased risk of crystallization.
By using exhaust gas to drive urea droplets to form a swirling flow on the surface of the perforated spiral plate, the droplets can fully contact the perforated area, breaking them down into smaller particles, increasing the evaporation and decomposition time, and reducing the risk of crystallization.
It effectively reduces the formation of urea crystals, decreases deposition, improves the decomposition efficiency of urea, avoids clogging, and enhances the mixing effect of exhaust gas and urea.
Smart Images
Figure CN224478971U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of waste gas treatment technology, specifically to a pipeline-type urea mixing device. Background Technology
[0002] In existing technology, urea is sprayed vertically along the pipeline. When urea is sprayed through the nozzle onto the surface of a mixing orifice plate arranged along the airflow direction, the exhaust gas carries the urea droplets deposited on the surface of the mixing orifice plate, which evaporate and decompose along a spiral plate set below the mixing orifice plate. Part of the airflow flows out from the central hole of the spiral plate. In this case, urea is easily deposited along the surface of the mixing orifice plate and forms large urea droplets. These droplets then fall directly onto the outermost pipe wall through the opening area of the spiral plate, where there is no airflow, making it easy for urea crystals to form. Furthermore, part of the airflow flows out through the central hole of the spiral plate, further reducing the airflow velocity on the surface of the spiral plate. If large urea droplets are deposited on the surface of the spiral plate, they are difficult to break up, decompose, and evaporate by the high-speed airflow. Since the mass of urea droplets is much larger than that of gas, the crystals formed in the stagnant airflow area, if not completely decomposed in time, will continue to grow using these as nuclei, eventually forming urea crystal stones. Accumulation to a certain extent may block the urea flow channel. Utility Model Content
[0003] In view of this, this application provides a pipeline urea mixing device, which uses exhaust gas to drive urea droplets to form a swirling flow on the surface of an open spiral plate. After the droplets come into full contact with the through-hole area, they break down and decompose into smaller droplets, thereby accelerating the evaporation and decomposition of urea and reducing the risk of urea crystallization.
[0004] To achieve the above objectives, this application provides the following technical solution:
[0005] A pipeline-type urea mixing device, comprising:
[0006] A urea mixing pipeline, wherein a urea inlet and an exhaust gas inlet are provided on the urea mixing pipeline;
[0007] A urea nozzle holder is disposed on the outer periphery of the urea mixing pipeline and is connected to the urea inlet; a urea nozzle can be disposed on the urea nozzle holder and spray urea droplets into the urea mixing pipeline through the urea inlet.
[0008] A perforated spiral plate is installed in the urea mixing pipeline, and the perforated spiral plate has through holes evenly distributed on it.
[0009] Exhaust gas can enter the urea mixing pipeline through the exhaust gas inlet, and drive the urea droplets that enter the urea mixing pipeline through the urea inlet to be sprayed onto the surface of the perforated spiral plate; the urea droplets can form a swirling flow along the surface of the perforated spiral plate.
[0010] Optionally, the urea mixing pipeline includes an inlet section, a transition section, and a mixing section connected in sequence; the inlet section and the mixing section are both straight sections, and the transition section is an arc section; the urea inlet is located in the connection area between the inlet section and the transition section, and the exhaust gas inlet is located at the opening of the inlet section.
[0011] Optionally, there is an angle between the centerline of the inlet section and the centerline of the mixing section, and there is also an angle between the centerline of the urea nozzle seat and the centerline of the mixing section, and the centerline of the urea nozzle seat and the centerline of the inlet section are located on opposite sides of the centerline of the mixing section.
[0012] Optionally, it also includes an injection guide tube, through which the urea nozzle seat is connected to the urea inlet.
[0013] Optionally, the first end of the injection guide tube is connected to the urea nozzle seat, the second end of the injection guide tube is connected to the urea inlet, and the diameter of the injection guide tube gradually increases from the first end to the second end.
[0014] Optionally, the tangent plane at any point on the inner wall of the injection guide tube intersects with the perforated spiral plate.
[0015] Optionally, the perforated spiral plate is disposed in the connection area between the transition section and the mixing section, and the central axis of the perforated spiral plate coincides with the central axis of the mixing section.
[0016] Optionally, the perforated spiral plate includes a spiral plate body and a support portion. The support portion is disposed at the central axis of the spiral plate body, and the inner edge of the spiral plate body is attached to the outer periphery of the support portion, while the outer edge of the spiral plate body is attached to the inner wall of the urea mixing pipeline.
[0017] Optionally, the through hole includes a first through hole, a second through hole, and a third through hole, which are arranged sequentially along the radial direction of the spiral plate body from the outer edge of the spiral plate body to the inner edge of the spiral plate body; the diameter of the first through hole is larger than the diameter of the second through hole, and the diameter of the second through hole is larger than the diameter of the third through hole.
[0018] Optionally, the perforated spiral plate is connected to the inner wall of the urea mixing pipeline through the outer edge of the spiral plate body, or the perforated spiral plate is connected to the inner wall of the urea mixing pipeline through the support portion.
[0019] The pipeline urea mixing device of this application uses exhaust gas to drive urea droplets to form a swirling flow on the surface of an open spiral plate. After the droplets come into full contact with the through-hole area, they break down and decompose into smaller droplets, which accelerates the evaporation and decomposition of urea and reduces the risk of urea crystallization. Attached Figure Description
[0020] 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 or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.
[0021] Figure 1 This is a schematic diagram of the pipeline-type urea mixing device of this application;
[0022] Figure 2 This is a top view of the perforated spiral plate of this application;
[0023] Figure 3 Side view of the perforated spiral plate of this application Figure 1 ;
[0024] Figure 4 Side view of the perforated spiral plate of this application Figure 2 ;
[0025] Figure 5 This is a trajectory diagram of urea particles in the urea mixing pipeline of this application;
[0026] Figure 6 This is a streamline diagram of the urea mixing pipeline in this application;
[0027] Figure 7 This is a diagram showing the urea deposition distribution in the urea mixing pipeline of this application.
[0028] exist Figures 1-7 middle:
[0029] 1. Urea mixing pipeline; 11. Inlet section; 12. Transition section; 13. Mixing section; 14. Injection guide pipe; 2. Perforated spiral plate; 21. Spiral plate body; 22. Through hole; 221. First through hole; 222. Second through hole; 223. Third through hole; 23. Support part; 3. Urea nozzle seat. Detailed Implementation
[0030] This application provides a pipeline-type urea mixing device, in which urea droplets are driven by exhaust gas to form a swirling flow on the surface of an open spiral plate. After the droplets come into full contact with the through-hole area, they are broken down and decomposed into smaller droplets, which accelerates the evaporation and decomposition of urea and reduces the risk of urea crystallization.
[0031] 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 embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0032] like Figures 1-4 As shown, the pipeline-type urea mixing device provided in this application includes:
[0033] Urea mixing pipeline 1, which is equipped with a urea inlet and an exhaust gas inlet;
[0034] The urea nozzle seat 3 is located on the outer periphery of the urea mixing pipeline 1 and is connected to the urea inlet; the urea nozzle can be installed on the urea nozzle seat 3 and spray urea droplets into the urea mixing pipeline 1 through the urea inlet.
[0035] A perforated spiral plate 2 is installed in the urea mixing pipeline 1, and through holes 22 are evenly distributed on the perforated spiral plate 2.
[0036] Exhaust gas can enter the urea mixing pipeline 1 through the exhaust gas inlet, and drive the urea droplets entering the urea mixing pipeline 1 through the urea inlet to be sprayed onto the surface of the perforated spiral plate 2; the urea droplets can form a swirling flow along the surface of the perforated spiral plate 2, or the urea droplets can pass through the through hole 22 to reach the rear side of the perforated spiral plate 2.
[0037] In this application, the pipeline-type urea mixing device allows exhaust gas to enter the urea mixing pipeline 1 from the exhaust gas inlet, and to carry urea droplets entering from the urea inlet to form a high-speed swirling flow on the surface of the perforated spiral plate 2. This causes the urea droplets to flow backward along the surface of the spiral plate, that is, away from the exhaust gas inlet. The exhaust gas flow can more easily reach the rear side of the perforated spiral plate 2 through multiple evenly distributed through holes 22, which solves the problem in the prior art that exhaust gas can only flow out through the central hole of the spiral plate, and the excessive swirling effect generates a large exhaust back pressure.
[0038] On the other hand, this application eliminates the method of opening a hole in the center of the spiral plate in the prior art, and replaces the through hole 22 with multiple through holes 22 evenly distributed on the spiral plate. In this way, the urea droplets fully contact the opening area of the evenly distributed through holes 22 on the spiral plate 2 during the swirling process, making it easier for the urea droplets to break down and decompose, forming smaller urea droplets. This increases the time that urea stays on the spiral plate 2, allowing more time to be fully heated, increasing its heat exchange time, accelerating the evaporation and decomposition of urea, reducing the formation of urea crystals, and reducing urea deposition.
[0039] In a preferred embodiment, such as Figure 1As shown, the urea mixing pipeline 1 includes an inlet section 11, a transition section 12, and a mixing section 13 connected in sequence. The inlet section 11 and the mixing section 13 are both straight sections, while the transition section 12 is an arc section. The straight sections of the inlet section 11 and the mixing section 13 are connected by the arc section of the transition section 12. The centerline of the inlet section 11 and the centerline of the mixing section 13 form an angle that is approximately obtuse. The urea inlet is located in the connection area between the inlet section 11 and the transition section 12, and the exhaust gas inlet is located at the opening of the inlet section 11. This is equivalent to placing the urea inlet further away from the mixing section 13, increasing the distance between the urea inlet and the mixing section 13. Since there is an obtuse angle between the centerline of the inlet section 11 and the centerline of the mixing section 13, the area between the urea inlet and the exhaust gas inlet can be made more gentle, allowing the urea and exhaust gas to be mixed more thoroughly.
[0040] In a preferred embodiment, such as Figure 1 As shown, there is an angle between the centerline of the inlet section 11 and the centerline of the mixing section 13, and there is also an angle between the centerline of the urea nozzle seat 3 and the centerline of the mixing section 13. Furthermore, the centerline of the urea nozzle seat 3 and the centerline of the inlet section 11 are located on opposite sides of the centerline of the mixing section 13. The fact that the centerline of the urea nozzle seat 3 and the centerline of the inlet section 11 are located on opposite sides of the centerline of the mixing section 13 allows the initial injection direction of the urea droplets to be vector-added with the airflow direction at the exhaust gas inlet, resulting in a direction that is essentially consistent with the direction of the centerline of the mixing section 13. In other words, driven by the exhaust gas flow, the final injection direction of the urea droplets is essentially consistent with the direction of the centerline of the mixing section 13, ensuring that the urea droplets are sprayed onto the surface of the perforated spiral plate 2 as much as possible, rather than onto the inner wall of the mixing section 13's centerline.
[0041] The angle between the centerline of the inlet section 11 and the centerline of the mixing section 13 is preferably 150-160 degrees; the angle between the centerline of the urea nozzle seat 3 and the centerline of the mixing section 13 is preferably 10-15 degrees.
[0042] In a preferred embodiment, such as Figure 1 As shown, in order to further increase the mixing degree of urea droplets and exhaust gas, a spray guide pipe 14 is also set on the outer periphery of the urea mixing pipeline 1. The urea nozzle seat 3 is connected to the urea inlet through the spray guide pipe 14, which is equivalent to extending the urea injection point in the opposite direction to the airflow direction, further increasing the mixing distance and mixing time of urea and exhaust gas, so that the mixing process is more thorough.
[0043] In a preferred embodiment, such as Figure 1 As shown, the first end of the injection guide tube 14 is connected to the urea nozzle seat 3, the second end of the injection guide tube 14 is connected to the urea inlet, and the diameter of the injection guide tube 14 gradually expands from the first end to the second end.
[0044] The diameter of the injection guide tube 14 gradually expands from the first end to the second end, matching the divergent profile of the urea droplets ejected from the urea nozzle. The inner wall of the injection guide tube 14 can also constrain the injection path of the urea droplets to a certain extent, preventing the injection profile of the urea droplets from being too divergent and thus spraying onto the inner wall of the urea mixing pipeline 1, especially the inner wall of the transition section 12.
[0045] In a preferred embodiment, to ensure that urea droplets are sprayed onto the surface of the perforated spiral plate 2, rather than onto the inner wall of the urea mixing pipe 1, the tangential plane at any point on the inner wall of the spray guide pipe 14 intersects with the perforated spiral plate 2, i.e. Figure 1 In this process, the injection guide tube 14 extends from its second end edge towards the perforated spiral plate 2, and its extension line intersects the perforated spiral plate 2. In this way, the urea droplets are constrained by the inner wall of the injection guide tube 14, reducing the probability of them being sprayed onto the inner wall of the urea mixing pipeline 1.
[0046] In a preferred embodiment, such as Figure 1 As shown, the perforated spiral plate 2 is disposed in the connection area between the transition section 12 and the mixing section 13, and the central axis of the perforated spiral plate 2 coincides with the central axis of the mixing section 13.
[0047] The perforated spiral plate 2 is set in the connection area between the transition section 12 and the mixing section 13. Urea and exhaust gas have been fully mixed in the transition section 12, but the distance between the perforated spiral plate 2 and the urea nozzle seat 3 is not too far, so that the sprayed urea droplets deviate too much under the action of gravity, causing the urea droplets to be sprayed on the inner wall of the mixing section 13 and the transition section 12 instead of accurately spraying onto the surface of the perforated spiral plate 2.
[0048] In a preferred embodiment, such as Figures 2-4 As shown, the perforated spiral plate 2 includes a spiral plate body 21 and a support part 23. The support part 23 is disposed at the central axis of the spiral plate body 21, and the radial inner edge of the spiral plate body 21 is attached to the outer periphery of the support part 23, while the radial outer edge of the spiral plate body 21 is attached to the inner wall of the urea mixing pipeline 1.
[0049] The support part 23 can support and strengthen the spiral plate body 21; there is no gap between the radial inner edge of the spiral plate body 21 and the support part 23, and there is also basically no gap between its radial outer edge and the inner wall of the urea mixing pipeline 1. Urea droplets can flow backward along the surface of the spiral plate under the blowing of the exhaust gas, that is, in the direction away from the inlet section 11. The exhaust gas can be blown through the evenly distributed through holes 22, and a small number of urea droplets pass through the through hole 22 area. In this way, urea droplets are not easy to fall on the inner wall of the urea mixing pipeline 1 and cause deposition.
[0050] In a preferred embodiment, such as Figures 2-4 As shown, the through hole 22 includes a first through hole 122, a second through hole 222, and a third through hole 322. The first through hole 122, the second through hole 222, and the third through hole 322 are arranged sequentially along the radial direction of the spiral plate body 21 from the outer radial edge of the spiral plate body 21 to the inner radial edge of the spiral plate body 21. The diameter of the first through hole 122 is larger than the diameter of the second through hole 222, and the diameter of the second through hole 222 is larger than the diameter of the third through hole 322.
[0051] The closer to the outer radial edge of the spiral plate body 21, the lower the flow velocity of the urea droplets driven by the exhaust gas flow on the surface of the spiral plate body 21. The closer to the inner radial edge of the spiral plate body 21, the higher the flow velocity of the urea droplets driven by the exhaust gas flow. Therefore, in order to achieve radial uniformity of the urea droplets on the surface of the spiral plate body 21, the through holes 22 closer to the outer radial edge of the spiral plate body 21 are made larger, and the through holes 22 closer to the inner radial edge of the spiral plate body 21 are made smaller.
[0052] The through holes 22 on the spiral plate body 21 can be designed in various forms, such as circular or elliptical, which is conducive to the urea being broken down and evaporated on the surface of the spiral plate; the axial length of the spiral plate body 21 is preferably the length of one pitch.
[0053] In a preferred embodiment, such as Figure 1 As shown, in order to fix the perforated spiral plate 2 inside the urea mixing pipeline 1, the perforated spiral plate 2 can be connected to the inner wall of the urea mixing pipeline 1 through the outer edge of the spiral plate body 21, for example, by welding. Alternatively, the perforated spiral plate 2 can also be connected to the inner wall of the urea mixing pipeline 1 through the support part 23, for example, by providing a connecting rod between the support part 23 and the inner wall of the urea mixing pipeline 1.
[0054] like Figure 1 As shown, the mixing process of urea and waste gas is as follows: Waste gas enters the inner cavity of urea mixing pipeline 1 from the waste gas inlet of inlet section 11, and urea droplets are sprayed out from the urea nozzle set at urea nozzle seat 3. There are angles between the center line of urea nozzle seat 3 and the center line of inlet section 11 and the center line of mixing section 13. The position of the perforated spiral plate 2 in the connection area between mixing section 13 and transition section 12 can be finely adjusted so that all urea droplets are sprayed on the surface of the spiral plate.
[0055] Through CFD simulation, we can see that... Figure 5 The diagram shows the trajectory of urea particles in the urea mixing pipeline 1. Most of the urea droplets are sprayed onto the perforated spiral plate 2; while through... Figure 6The streamline diagram shows that the exhaust gas forms a swirling flow through the spiral plate, carrying urea droplets backward along the surface of the spiral plate. This ensures full contact with the open areas of the spiral plate, causing the urea droplets to continuously break down and decompose, forming smaller droplets, accelerating urea evaporation and decomposition, and reducing the risk of urea crystallization. Figure 7 As shown in the urea deposition distribution diagram, the urea deposition area is mainly distributed in a part of the perforated spiral plate 2, and there is basically no urea deposition on the inner wall of the urea mixing pipeline 1.
[0056] The basic principles of this application have been described above with reference to specific embodiments. However, it should be noted that the advantages, benefits, and effects mentioned in this application are merely examples and not limitations, and should not be considered as essential features of each embodiment of this application. Furthermore, the specific details disclosed above are for illustrative and facilitative purposes only, and are not limitations. These details do not limit the application to the necessity of employing the aforementioned specific details for implementation.
[0057] The block diagrams of devices, apparatuses, devices, and systems involved in this application are merely illustrative examples and are not intended to require or imply that they must be connected, arranged, or configured in the manner shown in the block diagrams. As those skilled in the art will recognize, these devices, apparatuses, devices, and systems can be connected, arranged, and configured in any manner. Words such as “comprising,” “including,” “having,” etc., are open-ended terms meaning “including but not limited to,” and are used interchangeably with them. The terms “or” and “and” as used herein refer to the word “or” and are used interchangeably with them unless the context clearly indicates otherwise. The term “such as” as used herein refers to the phrase “such as but not limited to,” and is used interchangeably with it.
[0058] It should also be noted that in the apparatus, equipment, and methods of this application, the components or steps can be disassembled or recombined. These disassemblies or recombinations should be considered as equivalent solutions of this application.
[0059] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use this application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein can be applied to other aspects without departing from the scope of this application. Therefore, this application is not intended to be limited to the aspects shown herein, but rather to be accorded the widest scope consistent with the principles and novel features disclosed herein.
[0060] It should be understood that the qualifiers “first,” “second,” “third,” “fourth,” “fifth,” and “sixth” used in the description of the embodiments of this application are only used to more clearly illustrate the technical solutions and are not intended to limit the scope of protection of this application.
[0061] The above description has been given for purposes of illustration and description. Furthermore, this description is not intended to limit the embodiments of this application to the forms disclosed herein. Although numerous exemplary aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, alterations, additions, and sub-combinations thereof.
Claims
1. A pipeline-type urea mixing device, characterized in that, include: A urea mixing pipeline, wherein a urea inlet and an exhaust gas inlet are provided on the urea mixing pipeline; A urea nozzle holder is disposed on the outer periphery of the urea mixing pipeline and is connected to the urea inlet; a urea nozzle can be disposed on the urea nozzle holder and spray urea droplets into the urea mixing pipeline through the urea inlet. A perforated spiral plate is installed in the urea mixing pipeline, and the perforated spiral plate has through holes evenly distributed on it. Exhaust gas can enter the urea mixing pipeline through the exhaust gas inlet, and drive the urea droplets that enter the urea mixing pipeline through the urea inlet to be sprayed onto the surface of the perforated spiral plate; the urea droplets can form a swirling flow along the surface of the perforated spiral plate.
2. The pipeline-type urea mixing device according to claim 1, characterized in that, The urea mixing pipeline includes an inlet section, a transition section, and a mixing section connected in sequence; the inlet section and the mixing section are both straight sections, and the transition section is an arc section; the urea inlet is located in the connection area between the inlet section and the transition section, and the exhaust gas inlet is located at the opening of the inlet section.
3. The pipeline-type urea mixing device according to claim 2, characterized in that, There is an angle between the centerline of the inlet section and the centerline of the mixing section, and there is also an angle between the centerline of the urea nozzle seat and the centerline of the mixing section. Furthermore, the centerline of the urea nozzle seat and the centerline of the inlet section are located on opposite sides of the centerline of the mixing section.
4. The pipeline-type urea mixing device according to claim 3, characterized in that, It also includes an injection guide tube, through which the urea nozzle seat is connected to the urea inlet.
5. The pipeline-type urea mixing device according to claim 4, characterized in that, The first end of the injection guide tube is connected to the urea nozzle seat, and the second end of the injection guide tube is connected to the urea inlet. The diameter of the injection guide tube gradually increases from the first end to the second end.
6. The pipeline-type urea mixing device according to claim 5, characterized in that, The tangent plane at any point on the inner wall of the injection guide tube intersects with the perforated spiral plate.
7. The pipeline-type urea mixing device according to any one of claims 2-6, characterized in that, The perforated spiral plate is disposed in the connection area between the transition section and the mixing section, and the central axis of the perforated spiral plate coincides with the central axis of the mixing section.
8. The pipeline-type urea mixing device according to claim 7, characterized in that, The perforated spiral plate includes a spiral plate body and a support portion. The support portion is located at the central axis of the spiral plate body, and the inner edge of the spiral plate body is attached to the outer periphery of the support portion. The outer edge of the spiral plate body is attached to the inner wall of the urea mixing pipeline.
9. The pipeline-type urea mixing device according to claim 8, characterized in that, The through holes include a first through hole, a second through hole, and a third through hole, which are arranged sequentially along the radial direction of the spiral plate body from the outer edge of the spiral plate body to the inner edge of the spiral plate body; the diameter of the first through hole is larger than the diameter of the second through hole, and the diameter of the second through hole is larger than the diameter of the third through hole.
10. The pipeline-type urea mixing device according to claim 8, characterized in that, The perforated spiral plate is connected to the inner wall of the urea mixing pipeline through the outer edge of the spiral plate body, or the perforated spiral plate is connected to the inner wall of the urea mixing pipeline through the support portion.