A urea hydrolysis mixing chamber
By introducing structures such as swirl plates and helical blades into the urea hydrolysis mixing chamber, the problem of insufficient mixing between urea droplets and high-temperature exhaust gas was solved, achieving full contact and efficient reaction between urea droplets and exhaust gas, and improving the NOx reduction efficiency.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- HEFEI SHENZHOU CATALSIS PURIFIER CO LTD
- Filing Date
- 2025-08-05
- Publication Date
- 2026-07-03
AI Technical Summary
In existing urea hydrolysis mixing chambers, the mixing of urea droplets and high-temperature exhaust gas is insufficient, resulting in low reaction efficiency. There is a lack of design to extend the residence time of the urea solution in the mixing chamber, which affects the completion of hydrolysis and pyrolysis reactions.
A urea hydrolysis mixing chamber was designed, comprising a shell, a top cover, an evaporation plate, a swirl plate, a guide plate, and spiral blades. The swirl plate generates turbulence, prolonging the contact time between urea droplets and high-temperature exhaust gas. The guide plate and spiral blades enhance the swirling effect of the airflow. Combined with honeycomb microchannels and a catalytic coating, the evaporation and pyrolysis reaction of urea droplets are promoted.
This improved the mixing efficiency of urea droplets and high-temperature exhaust gas, ensuring sufficient contact, enhancing the reaction effect, and increasing the NOx reduction efficiency.
Smart Images
Figure CN224442655U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of automotive engine exhaust purification technology, specifically to a urea hydrolysis mixing chamber. Background Technology
[0002] The urea hydrolysis mixing chamber is mainly used in the urea treatment process of selective catalytic reduction (SCR) systems to mix urea solution with tail gas. Urea is usually stored and transported in solution form. The mixing chamber ensures that the urea solution and tail gas are fully mixed before entering the catalyst. Inside the mixing chamber, the urea solution undergoes a hydrolysis reaction under the action of high-temperature tail gas to generate ammonia. The mixing chamber is designed to optimize the distribution of ammonia and ensure that ammonia is uniformly injected into the catalyst bed, thus maximizing the NOx reduction efficiency. The urea hydrolysis mixing chamber is a key component in the SCR system. It is essential for ensuring the effective hydrolysis of urea solution and the uniform distribution of ammonia, thereby achieving efficient NOx emission reduction.
[0003] In existing hydrolysis mixing chambers, urea solution is atomized into fine droplets by a spray system and then sprayed into the mixing chamber. These droplets are usually in the form of a solution with a certain concentration. High-temperature exhaust gas enters from the inlet at the bottom of the mixing chamber. This exhaust gas usually comes from the combustion process and contains nitrogen oxides that need to be reduced. However, during the reaction, due to the lack of a swirl plate and turbulence generation mechanism, the mixing of urea droplets and high-temperature exhaust gas may not be sufficient, resulting in low reaction efficiency. The lack of design to extend the residence time of urea solution in the mixing chamber may lead to insufficient contact between urea droplets and exhaust gas, affecting the completion of hydrolysis and pyrolysis reactions. Utility Model Content
[0004] The purpose of this invention is to provide a urea hydrolysis mixing chamber to solve the technical problems in the prior art where the mixing of urea droplets and high-temperature exhaust gas may be insufficient, resulting in low reaction efficiency. The lack of design to extend the residence time of urea solution in the mixing chamber may lead to insufficient contact between urea droplets and exhaust gas, affecting the completion of hydrolysis and pyrolysis reactions.
[0005] The technical problem to be solved by this utility model can be achieved through the following technical solution:
[0006] A urea hydrolysis mixing chamber, comprising a shell;
[0007] A top cover is connected to the top of the housing, and a disassembly mechanism is provided between the housing and the top cover;
[0008] A pipe is fixedly connected to the shell, and an exhaust pipe is connected to the end of the pipe away from the shell; a mixing chamber is provided inside the shell, a connecting frame is fixedly connected to the end of the mixing chamber, an evaporation plate is connected to the mixing chamber, a honeycomb microchannel is provided on the evaporation plate, and a spray system is connected between the shell and the evaporation plate;
[0009] A high-temperature exhaust gas inlet is provided at the bottom of the shell; a conveying pipe is provided below the mixing chamber, and a guide plate is connected to the side of the conveying pipe away from the mixing chamber; a dispersion plate is connected inside the guide plate, and the exhaust gas velocity is controlled by the gas holes and the dispersion plate through multi-stage airflow division to avoid excessively high local ammonia concentration; a partition plate is fixedly connected to the guide plate, and a baffle is fixedly connected to the partition plate; an air inlet pipe is provided on one side of the guide plate.
[0010] As a further embodiment of this utility model: the disassembly mechanism includes two connecting plates and a locking bolt, both connecting plates are connected to the housing, and the locking bolt is detachably connected between the two connecting plates.
[0011] As a further embodiment of this invention, the honeycomb microchannels are provided with a catalytic coating.
[0012] As a further embodiment of this utility model, the guide plate is provided with multiple air holes.
[0013] As a further embodiment of this utility model, a spiral blade is provided on one side of the guide plate.
[0014] As a further embodiment of this invention, the spiral blades are arranged obliquely.
[0015] As a further embodiment of this invention, a plurality of swirl plates are provided above the evaporation plate.
[0016] As a further embodiment of this invention, honeycomb microchannels are provided on each of the plurality of swirl plates.
[0017] As a further embodiment of this utility model, the baffle is an arc-shaped structure.
[0018] As a further embodiment of this utility model, the baffle plate is provided with multiple through holes.
[0019] The beneficial effects of this utility model are:
[0020] 1. In this invention, the urea solution is atomized by a spray system and injected into the mixing chamber. Multiple swirl plates generate turbulence, which initially mixes the urea droplets with the high-temperature exhaust gas, prolongs the residence time, and promotes droplet evaporation. The high-temperature exhaust gas enters from the high-temperature exhaust gas inlet at the bottom and flows upward through the delivery pipe. The exhaust gas forms a high-speed airflow through the air holes on the guide plate, impacting the urea droplets and accelerating the pyrolysis reaction. The obliquely designed spiral blades further enhance the swirling effect of the airflow, ensuring full contact between the urea droplets and the exhaust gas. The microchannels on the evaporation plate significantly increase the specific surface area. By utilizing the swirl plates to generate turbulence, it is possible to ensure that the urea droplets and the high-temperature exhaust gas are mixed rapidly and thoroughly, thereby improving the reaction efficiency.
[0021] 2. The dispersion plate of this utility model divides the airflow into multiple fine streams, improving the mixing uniformity. The through holes on the partition plate and baffle control the airflow path, avoiding uneven NH3 distribution caused by local eddies. The air inlet pipe replenishes fresh air, adjusting the oxygen concentration and temperature in the mixing chamber. The airflow in the second air inlet pipe and the through holes of the guide plate work together to form a three-dimensional swirling field. The through holes on the baffle finely adjust the airflow speed. The dispersion plate divides the airflow into multiple fine streams, which helps to improve the uniformity of the gas in the mixing chamber and reduce the local incomplete reaction caused by uneven mixing. Attached Figure Description
[0022] The present invention will be further described below with reference to the accompanying drawings.
[0023] Figure 1 This is a schematic diagram of the overall structure of this utility model;
[0024] Figure 2 This is an exploded structural diagram of the present invention;
[0025] Figure 3 This is a schematic diagram of the mixing chamber structure in this utility model;
[0026] Figure 4 yes Figure 3 A schematic diagram of the structure viewed from below.
[0027] In the diagram: 1. Shell; 2. Injection system; 3. Connecting plate; 4. Locking bolt; 5. Top cover; 6. Evaporator plate; 7. Pipe; 8. Exhaust pipe; 9. Baffle; 10. Guide plate; 11. Swirl plate; 13. Delivery pipe; 14. Inlet pipe; 15. Dispersion plate; 16. Air hole; 17. High-temperature exhaust gas inlet; 18. Connecting frame; 19. Mixing chamber; 21. Separator plate; 22. Spiral blade. Detailed Implementation
[0028] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present utility model.
[0029] like Figures 1-4 As shown, a urea hydrolysis mixing chamber includes a housing 1, a top cover 5 connected to the top of the housing 1, and a disassembly mechanism provided between the housing 1 and the top cover 5. The disassembly mechanism includes two connecting plates 3 and a locking bolt 4. The two connecting plates 3 are both connected to the housing 1, and the locking bolt 4 is detachably connected between the two connecting plates 3.
[0030] A pipe 7 is fixedly connected to the shell 1, and an exhaust pipe 8 is connected to the end of the pipe 7 away from the shell 1. A mixing chamber 19 is provided inside the shell 1, and a connecting frame 18 is fixedly connected to the end of the mixing chamber 19. An evaporation plate 6 is connected to the mixing chamber 19. A honeycomb microchannel is provided on the evaporation plate 6, and a catalytic coating is provided inside the honeycomb microchannel, upgrading the traditional planar plate to a three-dimensional microchannel structure, thereby improving the pyrolysis efficiency. Multiple swirl plates 11 are provided above the evaporation plate 6, and each of the multiple swirl plates 11 is provided with a honeycomb microchannel. An injection system 2 is connected between the shell 1 and the evaporation plate 6.
[0031] A high-temperature exhaust gas inlet 17 is provided at the bottom of the shell 1; a conveying pipe 13 is provided below the mixing chamber 19, and a guide plate 10 is connected to the side of the conveying pipe 13 away from the mixing chamber 19. The guide plate 10 is provided with multiple air holes 16, and a spiral blade 22 is provided on one side of the guide plate 10. The spiral blade 22 is obliquely arranged, and the oblique spiral blade 22 forms a secondary vortex; a dispersion plate 15 is connected inside the guide plate 10. The air holes 16 and the dispersion plate 15 control the exhaust gas velocity through multi-stage airflow division to avoid excessively high local ammonia concentration; a partition plate 21 is fixedly connected to the guide plate 10, and a baffle 9 is fixedly connected to the partition plate 21. The baffle 9 has an arc-shaped structure and multiple through holes; an air inlet pipe 14 is provided on one side of the guide plate 10.
[0032] The working principle of this invention: This device, through a multi-stage structural design, achieves efficient decomposition of urea solution, uniform mixing of ammonia, and tail gas treatment. The urea solution is atomized by the injection system 2 and sprayed into the mixing chamber 19. Multiple swirling plates 11 generate turbulence, causing the urea droplets to initially mix with the high-temperature tail gas, extending the residence time and promoting droplet evaporation. The high-temperature tail gas enters from the bottom high-temperature tail gas inlet 17 and flows upward through the conveying pipe 13. The tail gas forms a high-speed airflow through the vents 16 on the guide plate 10, impacting the urea droplets and accelerating the pyrolysis reaction. The obliquely designed spiral blades 22 further enhance the airflow swirling effect, ensuring full contact between the urea droplets and the tail gas. The microchannels on the evaporation plate 6 significantly increase the specific surface area. Cyanic acid and water vapor react rapidly in the microchannel. The catalytic coating in the microchannel can reduce the reaction temperature. The dispersion plate 15 divides the airflow into multiple fine streams to improve the mixing uniformity. The through holes on the separator plate 21 and the baffle 9 control the airflow path and avoid uneven NH3 distribution caused by local eddies. The air inlet pipe 14 replenishes fresh air and adjusts the oxygen concentration and temperature in the mixing chamber 19. The airflow in the air inlet pipe 14 and the through holes of the guide plate 10 work together to form a three-dimensional swirling field. The through holes on the baffle 9 finely adjust the airflow speed. The connecting plate 3 and the locking bolt 4 allow for quick disassembly of the top cover 5, which is convenient for cleaning the urea crystals on the evaporation plate 6 and the guide plate 10. The combination of the spiral blade 22 and the oblique air hole 16 achieves precise control of the airflow speed and direction.
[0033] The above description details one embodiment of the present utility model, but it is merely a preferred embodiment and should not be construed as limiting the scope of the present utility model. All equivalent variations and improvements made within the scope of the present utility model application should still fall within the patent coverage of the present utility model.
Claims
1. A urea hydrolysis mixing chamber, comprising a shell (1); characterized in that: The top of the housing (1) is connected to a top cover (5), and a disassembly mechanism is provided between the housing (1) and the top cover (5); A pipe (7) is fixedly connected to the shell (1), and an exhaust pipe (8) is connected to the end of the pipe (7) away from the shell (1); a mixing chamber (19) is provided inside the shell (1), a connecting frame (18) is fixedly connected to the end of the mixing chamber (19), an evaporation plate (6) is connected to the mixing chamber (19), a honeycomb microchannel is provided on the evaporation plate (6), and a spray system (2) is connected between the shell (1) and the evaporation plate (6); The bottom of the housing (1) is provided with a high-temperature exhaust gas inlet (17); a conveying pipe (13) is provided below the mixing chamber (19), and a guide plate (10) is connected to the side of the conveying pipe (13) away from the mixing chamber (19); a dispersion plate (15) is connected inside the guide plate (10); a partition plate (21) is fixedly connected to the guide plate (10), and a baffle (9) is fixedly connected to the partition plate (21); an air inlet pipe (14) is provided on one side of the guide plate (10).
2. The urea hydrolysis mixing chamber according to claim 1, characterized in that, The disassembly mechanism includes two connecting plates (3) and a locking bolt (4). Both connecting plates (3) are connected to the housing (1), and the locking bolt (4) is detachably connected between the two connecting plates (3).
3. The urea hydrolysis mixing chamber according to claim 1, characterized in that The honeycomb microchannels are equipped with a catalytic coating.
4. The urea hydrolysis mixing chamber according to claim 1, characterized in that The guide plate (10) is provided with a plurality of air holes (16).
5. The urea hydrolysis mixing chamber according to claim 1, characterized in that A spiral blade (22) is provided on one side of the guide plate (10).
6. A urea hydrolysis mixing chamber according to claim 5, wherein The spiral blades (22) are arranged obliquely.
7. The urea hydrolysis mixing chamber according to claim 1, characterized in that Multiple swirl plates (11) are provided above the evaporator plate (6).
8. A urea hydrolysis mixing chamber according to claim 7, wherein Each of the multiple swirl plates (11) is provided with a honeycomb-shaped microchannel.
9. The urea hydrolysis mixing chamber according to claim 1, characterized in that The baffle (9) has an arc-shaped structure.
10. The urea hydrolysis mixing chamber according to claim 1, characterized in that The baffle (9) has multiple through holes.