SCR (Selective Catalytic Reduction) mixing device for preventing urea crystallization
By introducing a dispersing component and a mixing component into the SCR mixing unit, the problem of insufficient mixing between urea and exhaust gas was solved, achieving more efficient mixing and purification effects, reducing the risk of crystallization blockage, and extending the equipment life.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- HEFEI SHENZHOU CATALSIS PURIFIER CO LTD
- Filing Date
- 2025-08-14
- Publication Date
- 2026-05-15
AI Technical Summary
In existing SCR mixing devices, urea and exhaust gas are difficult to mix quickly and thoroughly, resulting in incomplete hydrolysis of urea, which easily leads to crystal formation and blockage of the exhaust pipe.
The SCR mixing device includes a dispersing component and a mixing component. The dispersing component disperses urea droplets through a dispersing roller, while the mixing component enhances the mixing effect through mixing blades, ensuring that the urea and exhaust gas are in full contact.
It significantly improves the mixing efficiency of urea and exhaust gas, reduces the formation of urea crystals, lowers the risk of exhaust pipe blockage, extends equipment maintenance cycles, and improves exhaust gas purification efficiency.
Smart Images
Figure CN224244953U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the technical field of automobile engine exhaust purification, specifically to an SCR mixing device for preventing urea crystallization. Background Technology
[0002] SCR, or Selective Catalytic Reduction, is a treatment process for nitrogen oxides (NOx) in diesel vehicle exhaust emissions. The SCR mixing unit, designed to prevent urea crystallization, primarily improves the mixing effect between urea and exhaust gas, preventing urea crystallization and clogging of the exhaust pipe, thus increasing exhaust gas purification efficiency. It is applied to the aftertreatment assembly of diesel vehicles and is an important component of the diesel engine exhaust gas purification system. After exiting the turbine, the exhaust gas enters the exhaust mixing unit. A urea metering injection device is installed on the mixing unit. Urea, injected through the urea nozzle, mixes with the exhaust gas within the mixing unit and undergoes thorough hydrolysis to form ammonia. This ammonia, in turn, reduces the nitrogen oxides in the exhaust gas into nitrogen and water in the SCR catalyst (catalytic reduction catalyst).
[0003] The efficiency of urea hydrolysis directly affects the amount of ammonia generated. Traditional mixing devices often use simple straight pipes or single-stage guide vanes, resulting in laminar flow of the exhaust gas with uneven velocity distribution (high velocity at the center and low velocity at the edges). Droplets ejected from the urea nozzles are prone to directly impacting the pipe wall due to inertia or getting trapped in the low-velocity backflow zone, failing to make sufficient contact with the high-speed mainstream exhaust gas. This makes it difficult for urea and exhaust gas to mix quickly and thoroughly, leading to incomplete urea hydrolysis. A large amount of undecomposed urea droplets adhere to the inner wall of the pipe, easily forming stubborn crystals that clog the exhaust pipe and severely affect the system's operational stability. Utility Model Content
[0004] This invention provides an SCR mixing device to prevent urea crystallization, which can solve the problem in the prior art that it is difficult to achieve rapid and sufficient mixing of urea and exhaust gas, resulting in incomplete urea hydrolysis.
[0005] An SCR mixing device for preventing urea crystallization includes an intake pipe, an exhaust pipe, a mixing mechanism, and a urea injection mechanism. The urea injection mechanism is used to inject urea into the mixing mechanism. The mixing mechanism includes a housing and a mixing component. The intake pipe and the exhaust pipe are both connected to the housing. The mixing component includes a cylindrical cavity, a dispersing component, and a mixing component. The cylindrical cavity is fixedly connected to the housing. The dispersing component is disposed at one end of the cylindrical cavity near the urea injection mechanism, and the mixing component is disposed at one end of the cylindrical cavity away from the urea injection mechanism.
[0006] According to one embodiment of this utility model, the dispersing component includes a plurality of dispersing rollers, all of which are horizontally fixedly connected to a cylindrical cavity. An inclined surface is formed on the side of the cylindrical cavity, and the dispersing rollers are arranged at equal intervals along the inclined surface. The top of the inclined surface is located directly below the urea injection mechanism, and the bottom of the inclined surface is located slightly below the side of the urea injection mechanism. A plurality of equally spaced slots are formed on the inclined surface, and the two ends of the dispersing rollers are respectively embedded in the corresponding slots. The slots have an arc-shaped structure.
[0007] According to one embodiment of the present invention, the mixing component includes a connecting frame and mixing blades. The top of the connecting frame is fixedly connected to a cylindrical cavity, and the bottom of the connecting frame is fixedly connected to the mixing blades, with the mixing blades located directly below the cylindrical cavity. The mixing blades include a partition plate and a guide plate. The partition plate is vertically fixedly connected to the connecting frame, and the guide plate is inclinedly fixedly connected to the partition plate. The mixing blades also include reinforcing ribs, which are fixedly disposed between the partition plate and the guide plate. A plurality of mixing blades are arranged in a circular array at the bottom of the connecting frame.
[0008] The advantages of this utility model compared to the prior art are:
[0009] By incorporating a dispersing and mixing component, the mixing efficiency of urea and exhaust gas is significantly improved. The dispersing component disperses urea droplets, greatly increasing the contact area between urea and exhaust gas. The mixing component further enhances the mixing degree, effectively reducing urea crystallization caused by incomplete hydrolysis, lowering the risk of exhaust pipe blockage, extending equipment maintenance cycles, and ensuring stable system operation. Simultaneously, more thorough mixing promotes the reduction reaction of nitrogen oxides, improving exhaust gas purification efficiency and helping diesel vehicle exhaust emissions meet stricter environmental standards.
[0010] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description
[0011] The above and / or additional aspects and advantages of this utility model will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:
[0012] Figure 1 This is a three-dimensional structural diagram of an SCR mixing device for preventing urea crystallization.
[0013] Figure 2 This is a three-dimensional structural cross-sectional view of the hybrid mechanism in this utility model.
[0014] Figure 3This is a three-dimensional structural diagram of the hybrid component in this utility model.
[0015] Figure 4 This is a three-dimensional structural diagram of the cylindrical cavity in this utility model.
[0016] Figure 5 This is a three-dimensional structural diagram of the hybrid blades in this utility model.
[0017] Figure 6 This is a top view of the hybrid blades in this utility model.
[0018] The reference numerals in the figures include:
[0019] 1. Inlet pipe; 2. Exhaust pipe; 3. Mixing mechanism; 4. Urea injection mechanism; 5. Housing; 6. Mixing assembly; 7. Cylindrical cavity; 8. Dispersing component; 9. Mixing component; 10. Dispersing roller; 11. Inclined surface; 12. Slot; 13. Connecting frame; 14. Mixing blade; 15. Separator plate; 16. Guide plate; 17. Reinforcing rib. Detailed Implementation
[0020] The specific embodiments of this utility model are described in detail below, but it should be understood that the protection scope of this utility model is not limited to the specific embodiments.
[0021] First Embodiment
[0022] Please see Figures 1 to 6 As shown, an SCR mixing device for preventing urea crystallization includes an intake pipe 1, an exhaust pipe 2, a mixing mechanism 3, and a urea injection mechanism 4. The urea injection mechanism 4 is used to inject urea into the mixing mechanism 3. The mixing mechanism 3 includes a housing 5 and a mixing component 6. The intake pipe 1 and the exhaust pipe 2 are both connected to the housing 5. The mixing component 6 includes a cylindrical cavity 7, a dispersing component 8, and a mixing component 9. The cylindrical cavity 7 is fixedly connected to the housing 5. The dispersing component 8 is disposed inside the cylindrical cavity 7 near one end of the urea injection mechanism 4, and the mixing component 9 is disposed inside the cylindrical cavity 7 away from the urea injection mechanism 4. The urea injection mechanism 4 includes a urea nozzle, which is connected to the housing 5 and located directly above the cylindrical cavity 7.
[0023] During the diesel vehicle exhaust treatment process, the exhaust gas enters the housing 5 of the mixing mechanism 3 through the intake pipe 1, and then flows into the cylindrical cavity 7. At this time, the urea injection mechanism 4 injects urea into the cylindrical cavity 7, where it first encounters the dispersing component 8. The dispersing component 8 disperses the urea droplets into smaller particles, increasing the contact area between the urea and the exhaust gas. Then, the dispersed urea particles and the exhaust gas continue to flow forward, and under the action of the mixing component 9, the two are further and thoroughly mixed.
[0024] Through the combined action of the dispersing component 8 and the mixing component 9, urea and exhaust gas are fully mixed before reaching the SCR catalyst to form a mixed gas. The mixed gas then enters the SCR catalyst through the exhaust pipe 2, where nitrogen oxides in the mixed gas are reduced to nitrogen and water, completing the exhaust gas purification process.
[0025] By incorporating the dispersing component 8 and the mixing component 9, the mixing efficiency of urea and exhaust gas is significantly improved. The dispersing component 8 disperses the urea droplets, greatly increasing the contact area between urea and exhaust gas. The mixing component 9 further enhances the mixing degree, effectively reducing urea crystallization caused by incomplete hydrolysis, lowering the risk of blockage in the exhaust pipe, extending equipment maintenance cycles, and ensuring stable system operation. Simultaneously, the more thorough mixing promotes the reduction reaction of nitrogen oxides, improving exhaust gas purification efficiency and helping diesel vehicle exhaust emissions meet stricter environmental standards.
[0026] Second Embodiment
[0027] Based on the first embodiment, the dispersing component 8 includes a plurality of dispersing rollers 10, all of which are horizontally fixedly connected to the cylindrical cavity 7. An inclined surface 11 is provided on the side of the cylindrical cavity 7, and the dispersing rollers 10 are arranged at equal intervals along the inclined surface 11. The top of the inclined surface 11 is located directly below the urea injection mechanism 4, and the bottom of the inclined surface 11 is located below the side of the urea injection mechanism 4. A plurality of equally spaced slots 12 are provided on the inclined surface 11, and the two ends of the dispersing rollers 10 are respectively embedded in the corresponding slots 12. The slots 12 have an arc-shaped structure.
[0028] The urea injection mechanism 4 sprays droplets that directly impact the dispersing rollers 10 located on the inclined surface 11 directly below it. The horizontally fixed dispersing rollers 10, equidistantly spaced along the inclined surface 11, disperse the urea droplets into fine particles. Under the structural action of the inclined surface 11, the impacted urea particles spread downwards along the inclined surface 11, further extending their contact range with the exhaust gas and achieving more thorough premixing. The arc-shaped grooves 12 securely engage both ends of the dispersing rollers 10, ensuring a stable and continuous dispersing process.
[0029] Third Embodiment
[0030] Based on the first embodiment, the mixing component 9 includes a connecting frame 13 and mixing blades 14. The top of the connecting frame 13 is fixedly connected to the cylindrical cavity 7, and the bottom of the connecting frame 13 is fixedly connected to the mixing blades 14, with the mixing blades 14 located directly below the cylindrical cavity 7. The mixing blades 14 include a partition plate 15 and a guide plate 16. The partition plate 15 is vertically fixedly connected to the connecting frame 13, and the guide plate 16 is inclinedly fixedly connected to the partition plate 15. The mixing blades 14 also include reinforcing ribs 17, which are fixedly disposed between the partition plate 15 and the guide plate 16. A plurality of mixing blades 14 are provided and arranged in a circular array at the bottom of the connecting frame 13.
[0031] After initial mixing by the dispersing component 8, the urea particles and exhaust gas flow downwards to the bottom of the cylindrical cavity 7, where they encounter the mixing blades 14 arranged in a ring array. Vertical partition plates 15 divide the mixed airflow into multiple independent channels, while inclined guide plates 16 change the airflow direction, causing vortices and turbulence to form within each channel. During this process, the urea particles and exhaust gas collide and mix thoroughly. Reinforcing ribs 17 securely connect the partition plates 15 and the guide plates 16, ensuring the mixing blades 14 maintain structural stability under the impact of high-speed airflow.
[0032] The mixing blades 14 significantly improve the uniformity of gas-liquid mixing. The separator 15 and the guide plate 16 work together to break the limitations of traditional mixing modes and effectively avoid the risk of crystallization caused by excessively high local urea concentrations. The annular array layout expands the mixing coverage area, and the reinforcing ribs 17 enhance the structural strength of the blades, reduce component wear, improve the reliability and durability of the mixing device, and further ensure the efficiency of exhaust gas purification.
[0033] The above-disclosed embodiments are only a few specific examples of the present utility model. However, the embodiments of the present utility model are not limited thereto. Any changes that can be conceived by those skilled in the art should fall within the protection scope of the present utility model.
Claims
1. An SCR mixing device for preventing urea crystallization, characterized in that, It includes an intake pipe (1), an exhaust pipe (2), a mixing mechanism (3), and a urea injection mechanism (4). The urea injection mechanism (4) is used to inject urea into the mixing mechanism (3). The mixing mechanism (3) includes a housing (5) and a mixing component (6). The intake pipe (1) and the exhaust pipe (2) are both connected to the housing (5). The mixing component (6) includes a cylindrical cavity (7), a dispersing component (8), and a mixing component (9). The cylindrical cavity (7) is fixedly connected to the housing (5). The dispersing component (8) is located in the cylindrical cavity (7) at one end near the urea injection mechanism (4). The mixing component (9) is located in the cylindrical cavity (7) at one end away from the urea injection mechanism (4).
2. The SCR mixing device for preventing urea crystallization as described in claim 1, characterized in that, The dispersing component (8) includes several dispersing rollers (10), and all the dispersing rollers (10) are horizontally connected to the cylindrical cavity (7).
3. The SCR mixing device for preventing urea crystallization as described in claim 2, characterized in that, The cylindrical cavity (7) has an inclined surface (11) on its side, and the dispersing roller (10) is arranged at equal intervals along the inclined surface (11).
4. The SCR mixing device for preventing urea crystallization as described in claim 3, characterized in that, The top of the inclined surface (11) is located directly below the urea injection mechanism (4), and the bottom of the inclined surface (11) is located below the side of the urea injection mechanism (4).
5. The SCR mixing device for preventing urea crystallization as described in claim 3, characterized in that, The inclined surface (11) is provided with a number of equally spaced slots (12), and the two ends of the dispersing roller (10) are respectively embedded in the corresponding slots (12).
6. The SCR mixing device for preventing urea crystallization as described in claim 5, characterized in that, The slot (12) has an arc-shaped structure.
7. The SCR mixing device for preventing urea crystallization as described in claim 1, characterized in that, The mixing component (9) includes a connecting frame (13) and a mixing blade (14). The top of the connecting frame (13) is fixedly connected to the cylindrical cavity (7), and the bottom of the connecting frame (13) is fixedly connected to the mixing blade (14). The mixing blade (14) is located directly below the cylindrical cavity (7).
8. The SCR mixing device for preventing urea crystallization as described in claim 7, characterized in that, The mixing blade (14) includes a partition plate (15) and a guide plate (16). The partition plate (15) is vertically fixedly connected to the connecting frame (13), and the guide plate (16) is inclinedly fixedly connected to the partition plate (15).
9. The SCR mixing device for preventing urea crystallization as described in claim 8, characterized in that, The mixing blade (14) also includes a reinforcing rib (17), which is fixedly disposed between the partition plate (15) and the guide plate (16).
10. The SCR mixing device for preventing urea crystallization as described in claim 7, characterized in that, The hybrid blades (14) are provided in a plurality of units and arranged in a ring array at the bottom of the connecting frame (13).