Pipeline type urea mixing device
By setting up an independent chamber in the multi-stage evaporation tube, the problems of complex structure and crystallization risk of existing devices are solved, and uniform mixing of urea and waste gas is achieved, and the risk of crystallization is reduced.
Patent Information
- Application Number
- CN202511050776.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-29
- Publication Date
- 2025-12-19
AI Technical Summary
Existing urea mixing devices have complex structures, large airflow pressure losses, and the gaps between staggered fins easily form airflow dead zones, while the blade edges are prone to crystallization.
The multi-stage evaporator is equipped with an independent first chamber and a second chamber. The exhaust gas releases heat in the first chamber to heat the evaporator, and carries urea droplets through the second chamber to decompose into multiple interlaced airflows, thereby improving mixing uniformity and reducing the risk of crystallization.
It improves the uniformity of urea mixing with waste gas, reduces the risk of crystallization on the surface of the evaporator tube, and optimizes airflow.
Smart Images
Figure CN121162385A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of waste gas treatment, in particular to a pipeline type urea mixing device. BACKGROUND
[0002] The urea mixing device of the prior art promotes the mixing of urea and waste gas by evaporating and decomposing urea through multiple layers of staggered fins, and has more components, a complex structure, and large airflow pressure loss. The staggered fin gaps are prone to form airflow dead zones, and crystals are prone to accumulate and grow at the edges of the blades. SUMMARY
[0003] Therefore, the present application provides a pipeline type urea mixing device, which improves the uniformity of the mixing of urea and waste gas and reduces the risk of crystallization by setting a first chamber and a second chamber independently in a multi-stage evaporation pipe.
[0004] In order to achieve the above purpose, the present application provides the following technical scheme:
[0005] A pipeline type urea mixing device, comprising:
[0006] A urea mixing pipeline, provided with a urea inlet and a waste gas inlet;
[0007] A urea nozzle seat is arranged on the outer periphery of the urea mixing pipeline and is in communication with the urea inlet; a urea nozzle can be arranged on the urea nozzle seat and sprays urea droplets into the urea mixing pipeline through the urea inlet;
[0008] A multi-stage evaporation pipe is arranged in the urea mixing pipeline, and the multi-stage evaporation pipe comprises a first chamber and a second chamber which are independent of each other;
[0009] Waste gas can enter the urea mixing pipeline through the waste gas inlet and flow through the first chamber and the second chamber respectively; the waste gas flowing through the first chamber can heat the multi-stage evaporation pipe; the waste gas can also carry the urea droplets entering the urea mixing pipeline from the urea inlet through the second chamber, and the waste gas carrying the urea droplets can be decomposed to form multiple staggered airflows.
[0010] Optionally, the urea mixing pipeline comprises a first straight section, an arc transition section and a second straight section connected in sequence, the multi-stage evaporation pipe is arranged in the inner cavity of the first straight section, the urea inlet is arranged on the outer side wall of the first straight section, and the waste gas inlet is arranged at the opening of the first straight section.
[0011] Optionally, the multi-stage evaporation pipe comprises an outer pipe and a plurality of inner pipes arranged in the outer pipe and having parallel axes, two ends of the inner pipes are connected to the pipe wall of the outer pipe, and the inner cavity of the inner pipe communicates with the inner cavity of the urea mixing pipe through the opening of the end of the inner pipe.
[0012] The inner cavity of the inner pipe forms the first chamber, and the inner cavity of the outer pipe forms the second chamber.
[0013] The exhaust gas can flow into the first chamber from the gap between the urea mixing pipe and the outer pipe, and flow out from the opening of the other end of the inner pipe.
[0014] The exhaust gas can carry the urea droplets to flow into the gas inlet of the outer pipe, and after being cut and decomposed into a plurality of staggered airflows by the outer wall of the inner pipe, the exhaust gas flows out from the gas outlet of the outer pipe.
[0015] Optionally, the outer pipe is coaxially arranged with the first straight segment, and the multi-stage evaporation pipe is fixedly connected with the urea mixing pipe through a connecting support.
[0016] Optionally, the angle between the axis of the inner pipe and the axis of the outer pipe is less than 90°, and the end of the inner pipe close to the urea inlet is inclined away from the exhaust gas inlet.
[0017] Optionally, the inner pipes are uniformly distributed along the length direction and the radial direction of the outer pipe.
[0018] Optionally, the outer pipe is provided with a relief gap at a position opposite to the urea inlet, the relief gap extends from the outer side wall of the outer pipe to the gas inlet of the outer pipe.
[0019] Optionally, there is an angle between the center line of the urea nozzle seat and the center line of the first straight segment.
[0020] Optionally, it further comprises a spray guide pipe, the urea nozzle seat is connected to the urea inlet through the spray guide pipe, the first end of the spray guide pipe is connected to the urea nozzle seat, the second end of the spray guide pipe is connected to the urea inlet, and the diameter of the spray guide pipe gradually expands from the first end to the second end.
[0021] Optionally, the tangent plane at any point on the inner side wall of the spray guide pipe passes through the relief gap and intersects with the inner pipe.
[0022] The pipeline type urea mixing device of the application, the multi-stage evaporation pipe is provided with the first chamber and the second chamber which are independent of each other, on the one hand, the second chamber can decompose the initial gas flow of the exhaust gas carrying the urea liquid drops into a plurality of gas flows, which is beneficial to improve the uniformity of the mixing of urea and gas flow;
[0023] On the other hand, the exhaust gas can release heat and heat the multi-stage evaporation pipe when passing through the first chamber, which is beneficial to improve the surface temperature of the evaporation pipe, accelerate the decomposition of the urea liquid film under heating, and reduce the risk of crystallization. BRIEF DESCRIPTION OF DRAWINGS
[0024] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced below. Obviously, the drawings in the following description are only embodiments of the application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of the provided drawings.
[0025] Figure 1 It is a side view of the exhaust gas inlet side of the pipeline type urea mixing device of the application;
[0026] Figure 2 It is a side sectional view of the pipeline type urea mixing device of the application;
[0027] Figure 3 It is Figure 2 the sectional view at A-A;
[0028] Figure 4 It is the streamline diagram in the urea mixing pipeline of the application;
[0029] Figure 5 It is the urea drop distribution diagram in the urea mixing pipeline of the application;
[0030] Figure 6 It is the urea deposition distribution diagram in the urea mixing pipeline of the application.
[0031] In Figures 1-6 which:
[0032] 1, multi-stage evaporation pipe; 11, outer layer pipe; 12, inner layer pipe; 2, mixing pipeline; 21, injection guide pipe; 3, urea nozzle seat. DETAILED DESCRIPTION
[0033] The application provides a pipeline type urea mixing device, by arranging the first chamber and the second chamber which are independent of each other in the multi-stage evaporation pipe, the uniformity of the mixing of urea and exhaust gas is improved, and the surface temperature of the evaporation pipe is increased and the risk of crystallization is reduced.
[0034] With reference to the drawings of the embodiments of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments of the present application, all the other embodiments obtained by those of ordinary skill in the art without creative effort belong to the scope of the present application.
[0035] As shown in Figures 1-3 The pipeline type urea mixing device provided by the present application comprises:
[0036] A urea mixing pipeline 2 is provided with a urea inlet and an exhaust gas inlet;
[0037] A urea nozzle seat 3 is arranged on the outer periphery of the urea mixing pipeline 2 and is in communication with the urea inlet; a urea nozzle can be arranged on the urea nozzle seat 3 and sprays urea droplets into the urea mixing pipeline 2 through the urea inlet;
[0038] A multi-stage evaporation pipe is arranged in the urea mixing pipeline 2, and the multi-stage evaporation pipe comprises a first chamber and a second chamber which are independent of each other;
[0039] Exhaust gas can enter the urea mixing pipeline 2 through the exhaust gas inlet and flow through the first chamber and the second chamber respectively; the exhaust gas can release heat and heat the multi-stage evaporation pipe 1 when flowing through the first chamber; the exhaust gas can also carry urea droplets through the second chamber, and the exhaust gas carrying the urea droplets can be decomposed to form a plurality of staggered air flows.
[0040] The pipeline type urea mixing device of the present application is provided with the first chamber and the second chamber which are independent of each other, on the one hand, the second chamber can decompose the initial air flow of the exhaust gas carrying the urea droplets into a plurality of air flows, which is beneficial to improve the uniformity of the mixing of urea and air flow;
[0041] On the other hand, the exhaust gas can release heat and heat the multi-stage evaporation pipe 1 when passing through the first chamber, which is beneficial to increase the surface temperature of the evaporation pipe, accelerate the decomposition of the urea liquid film under heat, and reduce the risk of crystallization.
[0042] In a preferred embodiment, as shown in Figure 6 The urea mixing pipeline 2 comprises a first straight section, an arc-shaped transition section and a second straight section connected in sequence, the multi-stage evaporation pipe 1 is arranged in the inner cavity of the first straight section, the urea inlet is arranged on the outer side wall of the first straight section, and the exhaust gas inlet is arranged at the opening of the first straight section.
[0043] After the exhaust gas and the urea droplets are fully mixed in the multi-stage evaporation pipe in the first straight section, they pass through the arc-shaped transition section and the second straight section in sequence, which can reduce the deposition phenomenon and reduce the risk of crystallization.
[0044] In a preferred embodiment, as shown in Figure 2As shown, the multi-stage evaporation pipe 1 comprises an outer layer pipe 11 and a plurality of inner layer pipes 12 arranged in the outer layer pipe 11 and having parallel axes, the outer layer pipe 11 has an inlet end close to the exhaust gas inlet and an outlet end away from the exhaust gas inlet, and the inner layer pipes 12 are preferably cylindrical pipes, which can reduce the urea deposition area and make the gas flow and urea flow more smooth; the two ends of the inner layer pipes 12 are connected to the pipe wall of the outer layer pipe 11, and the inner cavities of the inner layer pipes 12 communicate with the inner cavity of the urea mixing pipe 2 through the openings of the two ends of the inner layer pipes 12;
[0045] The inner cavities of the inner layer pipes 12 form first chambers, and the inner cavity of the outer layer pipe 11 forms a second chamber;
[0046] The exhaust gas can flow into the first chambers through the gap between the urea mixing pipe 2 and the outer layer pipe 11, enter the opening at one end of the inner layer pipe 12, and flow out of the opening at the other end of the inner layer pipe 12;
[0047] The exhaust gas can carry urea droplets to flow into the inlet of the outer layer pipe 11, and be cut and decomposed into a plurality of staggered gas flows by the outer wall of the inner layer pipe 12, and then flow out of the outlet of the outer layer pipe 11.
[0048] In this way, after the exhaust gas and the urea droplets are mixed in the urea mixing pipe 2, the exhaust gas is divided into two gas flows, one of which enters the inner cavity of the outer layer pipe 11, i.e. the second chamber, and fully contacts the outer surface of the inner layer pipe 12 while wrapping the urea; the inner layer pipes 12 are preferably uniformly staggered in the outer layer pipe 11, which decomposes the initial exhaust gas into a plurality of gas flows, and the exhaust gas carrying the urea droplets collides with and is decomposed by the outer wall of the inner layer pipe 12, which is conducive to the full evaporation and decomposition of the urea droplets to generate NH3, and the outer wall of the inner layer pipe 12 forms a plurality of staggered gas flows, and the streamline diagram is as shown in Figure 4 The decomposed NH3 can be fully mixed with the exhaust gas, improving the mixing uniformity;
[0049] The other gas flow passes through the inner cavities of the inner layer pipes 12, i.e. the first chambers, along the gap between the outer side wall of the outer layer pipe 11 and the inner side wall of the urea mixing pipe 2, and then flows out to the gap between the outer layer pipe 11 and the urea mixing pipe 2 again, and flows in the inner cavity of the urea mixing pipe 2 towards the direction away from the exhaust gas inlet, i.e. towards the transition section and the second straight section, which can heat the inner layer pipes 12 of the multi-stage evaporation pipe 1, avoid excessive temperature drop of the inner layer pipes 12 due to the urea injection to the pipe wall of the inner layer pipes 12, and cause crystallization of the pipe wall of the inner layer pipes 12;
[0050] Of course, a small amount of gas flow also flows along the gap between the outer side wall of the outer layer pipe 11 and the inner side wall of the urea mixing pipe 2.
[0051] The CFD simulation results are as shown in Figure 5 and Figure 6 It can be seen from Figure 5 and Figure 6It can be seen that the urea drop point is concentrated in the middle region of the multi-stage evaporation pipe 1, and the urea deposition is uniformly distributed.
[0052] In a preferred embodiment, as shown in Figure 2 The outer layer pipe 11 is coaxially arranged with the first straight section, which can uniformly distribute the gap between the outer side wall of the outer layer pipe 11 and the inner side wall of the urea mixing pipe 2, and is conducive to the uniform flow of the gas flow. In addition, in order to fix the multi-stage evaporation pipe 1 in the urea mixing pipe 2, the multi-stage evaporation pipe 1 and the urea mixing pipe 2 can be fixedly connected through a connecting support.
[0053] In a preferred embodiment, as shown in Figure 2 The angle between the axis of the inner layer pipe 12 and the axis of the outer layer pipe 11 is less than 90°, which means that the axis of the inner layer pipe 12 and the axis of the outer layer pipe 11 are not perpendicular, and the end of the inner layer pipe 12 close to the urea inlet is inclined away from the exhaust gas inlet. As can be seen from Figure 2 , the upper end of the inner layer pipe 12 is inclined to the right, and the lower end of the inner layer pipe 12 is inclined to the left. At this time, the center line of the urea nozzle seat 3 and the axis of the inner layer pipe 12 are approximately at a 90-degree angle, which can maximize the contact area between the urea droplets and the wall of the inner layer pipe 12.
[0054] In this way, the inner layer pipe 12 is inclined in the outer layer pipe 11, and the angle between the inner layer pipe 12 and the urea nozzle seat 3 is matched, which can make the urea droplets fall as evenly as possible on the wall of the inner layer pipe 12, so that the urea droplets and the exhaust gas are fully mixed, and the mixing uniformity is improved.
[0055] In a preferred embodiment, as shown in Figure 3 The inner layer pipe 12 is uniformly distributed along the length direction and the radial direction of the outer layer pipe 11, so that the initial exhaust gas carrying the urea droplets is evenly dispersed into multiple gas streams.
[0056] Specifically, the center line of the urea nozzle seat 3 and the center line of the urea mixing pipe 2 are located on the same plane, and a plurality of inner layer pipes 12 are uniformly arranged along the vertical direction of the plane. In addition, the plurality of inner layer pipes 12 can be divided into front and rear groups along the length direction of the urea mixing pipe 2, and the two groups of inner layer pipes 12 are arranged in a staggered manner, so as to better receive the urea droplets carried by the exhaust gas. Of course, the plurality of inner layer pipes 12 can be divided into front, middle and rear groups along the length direction of the urea mixing pipe 2, and so on, which can be arranged according to the actual situation.
[0057] In this embodiment, the inner layer pipe 12 adopts a front four and rear three arrangement, where "front" refers to the direction close to the exhaust gas inlet, and "rear" refers to the direction away from the exhaust gas inlet. Of course, the arrangement can also be adjusted according to the situation.
[0058] In a preferred embodiment, as shown in Figure 2 and Figure 3As shown, the outer tube 11 is provided with a relief gap at a position opposite to the urea inlet, the relief gap extends from the outer sidewall of the outer tube 11 to the gas inlet of the outer tube 11.
[0059] In order to make the exhaust gas enter the urea mixing pipeline 2 from the exhaust gas inlet and fully mix with the urea droplets, the outer tube 11 is provided with a relief gap at a position opposite to the urea inlet, the relief gap is not provided with the inner tube 12, and the exhaust gas and the urea droplets can fully mix at the relief gap and then reach the inner tube 12; the relief gap extends from the outer sidewall of the outer tube 11 to the gas inlet of the outer tube 11, so that the inner tube 12 is as exposed as possible relative to the urea nozzle seat 3, so that the exhaust gas carrying the urea droplets is sprayed on the outer wall of the inner tube 12 as much as possible.
[0060] In a preferred embodiment, as shown, Figure 2 The center line of the urea nozzle seat 3 and the center line of the first straight line segment form an angle, so as to prolong the mixing path of the urea droplets and the exhaust gas and increase the mixing time.
[0061] In a preferred embodiment, as shown, Figure 2 In order to further increase the mixing path of the urea droplets and the exhaust gas, a spray guide pipe 21 is further provided on the outer periphery of the urea mixing pipeline 2, the urea nozzle seat 3 is connected to the urea inlet through the spray guide pipe 21, the first end of the spray guide pipe 21 is connected to the urea nozzle seat 3, the second end of the spray guide pipe 21 is connected to the urea inlet, the inner diameter of the spray guide pipe 21 gradually expands from the first end to the second end, the inner diameter of the spray guide pipe 21 gradually expanding from the first end to the second end matches the divergence profile of the urea droplets sprayed by the urea nozzle, and the inner sidewall of the spray guide pipe 21 can also constrain the spray path of the urea droplets to a certain extent, avoiding the spray profile of the urea droplets being too divergent and sprayed on the inner sidewall of the urea mixing pipeline 2.
[0062] In a preferred embodiment, as shown, Figure 2 In order to make the urea droplets be sprayed on the outer wall of the inner tube 12 as much as possible, the tangent plane of any point on the inner sidewall of the spray guide pipe 21 passes through the relief gap and intersects with the inner tube 12, that is, Figure 2 The spray guide pipe 21 is continued to extend in the direction of the inner tube 12 from the second end edge thereof, and the extension line thereof passes through the relief gap and intersects with the inner tube 12, so that the urea droplets are constrained by the inner sidewall of the spray guide pipe 21, thereby improving the probability of being sprayed on the outer wall of the inner tube 12.
[0063] The above describes the basic principles of the present application in combination with specific embodiments, but it should be noted that the advantages, benefits, effects and the like mentioned in the present application are only examples and are not limiting, and these advantages, benefits, effects and the like cannot be considered as necessary for each embodiment of the present application. In addition, the above specific details disclosed are only for the purpose of illustration and understanding, and are not limiting, and the above details do not limit the present application to be necessarily implemented with the above specific details.
[0064] The block diagrams of the devices, apparatuses, equipment, systems involved in the present application are only illustrative examples and are not intended to require or imply the connection, arrangement, configuration shown in the block diagrams. As those skilled in the art will recognize, these devices, apparatuses, equipment, systems can be connected, arranged, configured in any manner. Words such as "include", "contain", "have" and the like are open-ended words, mean "including but not limited to", and can be used interchangeably. The words "or" and "and" used herein mean the word "or", and can be used interchangeably, unless the context clearly indicates otherwise. The word "such as" used herein means the phrase "such as but not limited to", and can be used interchangeably.
[0065] It should also be noted that in the devices, equipment and methods of the present application, each component or each step can be decomposed or recombined. These decompositions or recombinations should be considered as equivalent solutions of the present application.
[0066] The above description of the disclosed aspects is provided so that any person skilled in the art can make or use the present application. Various modifications to these aspects will be 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 the present application. Therefore, the present application is not intended to be limited to the aspects shown herein, but is intended to be accorded the widest scope consistent with the principles and novel features disclosed herein.
[0067] It should be understood that the limiting words "first", "second", "third", "fourth", "fifth" and "sixth" used in the description of the embodiments of the present application are only used for clearer description of the technical solutions, and cannot be used to limit the protection scope of the present application.
[0068] The above description has been given for the purpose of illustration and description. Furthermore, this description is not intended to limit the embodiments of the present application to the forms disclosed herein. Although a number of example aspects and embodiments have been discussed above, those skilled in the art will recognize certain modifications, alterations, changes, additions and sub-combinations thereof.
Claims
1. A pipeline type urea mixing device, characterized by, The application relates to a urea mixing pipeline, a urea nozzle seat and a multi-stage evaporation pipe. The urea mixing pipeline is provided with a urea inlet and an exhaust gas inlet. The urea nozzle seat is arranged on the outer periphery of the urea mixing pipeline and is in communication with the urea inlet. The urea nozzle can be arranged on the urea nozzle seat and sprays urea droplets into the urea mixing pipeline through the urea inlet. The multi-stage evaporation pipe is arranged in the urea mixing pipeline and comprises a first chamber and a second chamber which are independent of each other.
2. The pipeline urea mixing device of claim 1, wherein, Exhaust gas can enter the urea mixing pipeline through the exhaust gas inlet and flow through the first chamber and the second chamber respectively.
3. The pipeline urea mixing device of claim 2, wherein, The exhaust gas can release heat and heat the multi-stage evaporation pipe when flowing through the first chamber. The exhaust gas can also carry the urea droplets entering the urea mixing pipeline from the urea inlet through the second chamber, and the exhaust gas carrying the urea droplets can be decomposed to form a plurality of staggered air flows. The urea mixing pipeline comprises a first straight section, an arc-shaped transition section and a second straight section which are connected in sequence. The multi-stage evaporation pipe is arranged in the inner cavity of the first straight section.
4. The pipeline urea mixing device of claim 3, wherein, The urea inlet is arranged on the outer side wall of the first straight section.
5. The plumbing urea mixing device of claim 3, wherein, The exhaust gas inlet is arranged at the opening of the first straight section.
6. The plumbing urea mixing device of claim 3, wherein, The multi-stage evaporation pipe comprises an outer layer pipe and a plurality of inner layer pipes which are arranged in the outer layer pipe and have parallel axes.
7. The inline urea mixing device of claim 3, wherein, The two ends of the inner layer pipes are connected to the pipe wall of the outer layer pipe respectively.
8. A pipeline urea mixing device as claimed in any one of claims 7, characterised in that, The inner cavities of the inner layer pipes form the first chamber.
9. The inline urea mixing device of claim 8, wherein, The inner cavity of the outer layer pipe forms the second chamber.
10. The plumbing urea mixing device of claim 9, wherein, The exhaust gas can flow into the first chamber from the opening of one end of the inner layer pipe through the gap between the urea mixing pipeline and the outer layer pipe. The exhaust gas can carry the urea droplets to flow into the outer layer pipe from the gas inlet. The exhaust gas is cut and decomposed into a plurality of staggered air flows by the outer wall of the inner layer pipe and then flows out from the gas outlet of the outer layer pipe. The outer layer pipe is coaxially arranged with the first straight section. The multi-stage evaporation pipe and the urea mixing pipeline are fixedly connected through a connecting support. The angle between the axis of the inner layer pipe and the axis of the outer layer pipe is less than 90 degrees. The end of the inner layer pipe close to the urea inlet is inclined towards the direction away from the exhaust gas inlet. The inner layer pipes are uniformly distributed along the length direction and the radial direction of the outer layer pipe. An avoiding gap is arranged on the outer layer pipe at the position opposite to the urea inlet. The avoiding gap extends from the outer side wall of the outer layer pipe to the gas inlet of the outer layer pipe. The center line of the urea nozzle seat and the center line of the first straight section form an angle. A spray guide pipe is arranged. The first end of the spray guide pipe is connected to the urea nozzle seat. The second end of the spray guide pipe is connected to the urea inlet. The diameter of the spray guide pipe gradually increases from the first end to the second end. The tangent plane of any point on the inner side wall of the spray guide pipe passes through the avoiding gap and intersects with the inner layer pipe.