An ammonia gas mixer

Abstract

The present application belongs to the diesel engine exhaust aftertreatment technical field, specifically relates to a kind of ammonia gas mixers, including first mixer barrel, second mixer barrel and third mixer barrel, nozzle base is provided on third mixer barrel, ammonia gas nozzle is installed on nozzle base, one end of mixing chamber is fixed on third mixer barrel, the other end of mixing chamber is inserted into second mixer barrel, and second mixer barrel and third mixer barrel are connected by first sleeve and second sleeve;First mixer barrel is fixed to the upper end of third mixer barrel, the upper end of second mixer barrel is provided with cyclone plate, and the lower end of second mixer barrel is provided with mixer end cover.The present application discards the idea of the mixer of existing technology to be designed by spraying urea, from ammonia gas component diffusion characteristics, mixer structure is specially designed in stages mixing, premixing→submixing→main mixing→tail mixing are carried out in turn, prolongs mixing path, and improves ammonia mixing effect.

Description

Technical Field

[0001] This invention belongs to the field of diesel engine exhaust aftertreatment technology, and specifically relates to an ammonia mixer. Background Technology

[0002] With the adoption of the Euro 7 emission standard, the formulation of my country's next-stage China VII emission standard has also entered a fast track. To meet the more stringent China VII emission requirements, the use of ammonia injection as one of the China VII technical routes can not only solve the urea crystallization problem, but also further improve NOx conversion efficiency.

[0003] The existing ammonia mixers are still based on the original idea of ​​developing urea injection. They not only still use porous tube crushers, which are complex in structure and have high back pressure, but also inject ammonia directly, thus failing to improve the ammonia mixing effect.

[0004] Based on this, the present invention discloses a novel high-efficiency ammonia mixer from the perspective of gas flow component diffusion and mixing to solve the above-mentioned technical problems and meet the upcoming China VII emission requirements. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing technologies and provide an ammonia mixer. This ammonia mixer improves the ammonia mixing effect to enhance NOx conversion efficiency, thereby meeting the next stage of China VII emission standards. The mixer, based on the diffusion characteristics of ammonia components, features a uniquely designed premixing chamber for mixing with the exhaust gas. The gas then flows around the premixing chamber into the main mixing zone, extending the injection mixing path and improving the ammonia mixing effect. Swirling fins are installed near the nozzle at the inlet of the main mixing zone, allowing the premixed ammonia to enter the mixing chamber in a swirling manner and be slowly released at the center, forming a sandwich diffusion secondary mixture. A sealed plug is installed at the outlet of the main mixing chamber, forcing the sandwich-mixed exhaust gas to impact the plug and diffuse rapidly again, forming the main mixture, which then flows out from the second long trough. Finally, the ammonia is further mixed through the tail gas swirling flow. The entire mixer structure is divided into different mixing stages based on the ratio of exhaust gas to ammonia and their corresponding component characteristics, so that the ammonia mixing effect is continuously enhanced, thus achieving a thorough ammonia mixing effect within a limited structure.

[0006] To achieve the above technical objectives, the technical solution adopted in the embodiments of the present invention is as follows:

[0007] An ammonia mixer includes a first mixer cylinder, a second mixer cylinder, and a third mixer cylinder. A nozzle base is provided on the third mixer cylinder, and an ammonia nozzle is installed on the nozzle base. One end of a mixing chamber is fixed to the third mixer cylinder, and the other end of the mixing chamber extends into the second mixer cylinder. The second mixer cylinder and the third mixer cylinder are connected by a first sleeve and a second sleeve.

[0008] The first mixer cylinder is fixed to the upper end of the third mixer cylinder, the upper end of the second mixer cylinder is provided with a swirl plate, and the lower end of the second mixer cylinder is provided with a mixer end cap.

[0009] Furthermore, a heat insulation cotton and a first gasket are provided between the nozzle base and the ammonia nozzle.

[0010] Furthermore, a waist-shaped hole is provided on one side wall of the mixing chamber near the ammonia nozzle, and a second long groove is provided on the other side wall of the mixing chamber near the second mixer cylinder. Swirl fins and a first long groove are arranged sequentially between the waist-shaped hole and the second long groove.

[0011] The angle of the swirling fins is 25-40°, which is used to control the swirling effect of high-concentration ammonia gas.

[0012] Furthermore, a nozzle isolation plate is provided between the waist-shaped hole and the swirl fin, and the nozzle isolation plate is seamlessly connected to the mixing chamber;

[0013] A baffle is provided at the tail end of the mixing chamber, and the baffle is located on the rear side of the second long groove. The baffle is seamlessly connected to the mixing chamber.

[0014] Furthermore, the second sleeve is fixed to the third mixer cylinder, the first sleeve is fixed to the second mixer cylinder and the mixer end cap, the second sleeve is provided with a bushing, the first sleeve and the bushing are connected by a clamp, and a reinforcing rib and a second gasket are provided in the middle.

[0015] Furthermore, the swirl plate is fixed to the upper end of the second mixer cylinder by extending the swirl plate extension ring.

[0016] Furthermore, the first sleeve and the second sleeve are located between the first long groove and the second long groove;

[0017] The waist-shaped hole, the swirl fins, and the first long groove are all located inside the third mixer cylinder, and the second long groove is located inside the second mixer cylinder.

[0018] Furthermore, the ammonia nozzle has an injection hole on its side, and the diameter of the injection hole is 0.5-1mm.

[0019] Furthermore, the swirl plate is provided with small holes, semi-circular blades and swirl blades, which are arranged in a ring from the outside to the inside on the swirl plate.

[0020] The beneficial effects of the technical solution provided by the embodiments of the present invention are as follows:

[0021] (1) The mixer of the present invention has few internal components, is inexpensive, and is easy to manufacture.

[0022] (2) The present invention has a simple structure, low back pressure loss, and is easy to reduce fuel consumption.

[0023] (3) The ammonia mixer of the present invention provides a nozzle specifically for injecting ammonia based on the characteristics of ammonia.

[0024] (4) This invention abandons the idea of ​​using the spray urea to design the mixer in the existing technology. Starting from the diffusion characteristics of ammonia components, the mixer structure is uniquely designed with staged mixing, which performs premixing → secondary mixing → main mixing → tail mixing in sequence, which extends the mixing path and improves the ammonia mixing effect.

[0025] (5) This invention cleverly utilizes the difference in molecular mass between ammonia and tail gas and applies a sandwich impact diffusion method to fully enhance the mixing ability. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the ammonia mixer in an embodiment of the present invention.

[0027] Figure 2 This is a schematic diagram of the assembly components of the ammonia mixer in an embodiment of the present invention.

[0028] Figure 3 This is a schematic diagram of the mixing process of exhaust gas and ammonia in the mixer in an embodiment of the present invention.

[0029] Figure 4 This is a three-dimensional structural diagram of the flow of ammonia and exhaust gas within the mixer in an embodiment of the present invention.

[0030] Figure 5 yes Figure 1 A schematic diagram of the mixing chamber in an ammonia mixer.

[0031] Figure 6 yes Figure 5 Left view of the mixing chamber.

[0032] Figure 7 This is a schematic diagram of the ammonia gas supply principle of the nozzle.

[0033] Figure 8 This is a simulated cross-sectional axonometric view of the ammonia concentration distribution during the mixing process of exhaust gas and ammonia in the mixer in an embodiment of the present invention.

[0034] Figure 9 This is a simulated isometric diagram of the ammonia concentration distribution during the mixing process of exhaust gas and ammonia gas in the mixer in an embodiment of the present invention.

[0035] Figure 10This is a simulated cross-sectional front view of the ammonia concentration distribution during the mixing process of exhaust gas and ammonia in the mixer in an embodiment of the present invention.

[0036] Explanation of reference numerals in the attached drawings: 1-Ammonia nozzle; 2-Insulation cotton; 3-First gasket; 4-Nozzle base; 5-Nozzle isolation plate; 6-First mixer cylinder; 7-Mixing chamber; 8-Baffle; 9-Swirl plate; 10-Swirl plate extension ring; 11-Second mixer cylinder; 12-Mixer end cap; 13-First sleeve; 14-Reinforcing rib; 15-Clamp; 16-Second gasket; 17-Bushing; 18-Second sleeve; 19-Third mixer cylinder; 71-Oval orifice; 72-Swirl fin; 73-First long slot; 74-Second long slot; 91-Small hole; 92-Semi-circular blade; 93-Swirl blade. Detailed Implementation

[0037] In the description of this invention, it should be understood that the orientation or positional relationship indicated by directional terms such as "inner" and "outer", "upper" and "lower", "left" and "right" is usually based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this invention.

[0038] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0039] Example 1

[0040] like Figure 1 and 2 As shown, an ammonia mixer includes a first mixer cylinder 6, a second mixer cylinder 11, and a third mixer cylinder 19. A nozzle base 4 is provided on the third mixer cylinder 19, and an ammonia nozzle 1 is installed on the nozzle base 4. One end of a mixing chamber 7 is fixed to the third mixer cylinder 19, and the other end of the mixing chamber 7 extends into the second mixer cylinder 11. The second mixer cylinder 11 and the third mixer cylinder 19 are connected by a first sleeve 13 and a second sleeve 18.

[0041] The first mixer cylinder 6 is fixed to the upper end of the third mixer cylinder 19, the upper end of the second mixer cylinder 11 is provided with a swirl plate 9, and the lower end of the second mixer cylinder 11 is provided with a mixer end cap 12.

[0042] A heat insulation cotton 2 and a first gasket 3 are provided between the nozzle base 4 and the ammonia nozzle 1. The heat insulation cotton 2 is used to achieve heat insulation, and the first gasket 3 is used to achieve sealing between the nozzle base 4 and the ammonia nozzle 1.

[0043] like Figure 5 and 6 As shown, a waist-shaped hole 71 is provided on the side wall of the mixing chamber 7 near the ammonia nozzle 1, and a second long groove 74 is provided on the other side wall of the mixing chamber 7 near the second mixer cylinder 11. Swirl fins 72 and a first long groove 73 are arranged sequentially between the waist-shaped hole 71 and the second long groove 74.

[0044] The angle α of the swirl fin 72 is 25-40°, which is used to control the swirl effect of high-concentration ammonia gas.

[0045] Generally speaking, the smaller the angle α, the better the swirling effect. However, if the angle α is too small, the high-concentration ammonia gas will not enter the mixing chamber 7 from the swirling fins 72. Therefore, the angle needs to be set according to actual needs.

[0046] A nozzle isolation plate 5 is provided between the waist-shaped hole 71 and the swirl fin 72, and the nozzle isolation plate 5 is seamlessly connected to the mixing chamber 7.

[0047] A baffle 8 is provided at the tail end of the mixing chamber 7. The baffle 8 is located on the rear side of the second long groove 74 and is seamlessly connected to the mixing chamber 7.

[0048] The second sleeve 18 is fixed to the third mixer cylinder 19, the first sleeve 13 is fixed to the second mixer cylinder 11 and the mixer end cap 12, the second sleeve 18 is provided with a bushing 17, the first sleeve 13 and the bushing 17 are connected by a clamp 15, and the middle is supplemented by a reinforcing rib 14 and a second gasket 16.

[0049] The swirl plate 9 is extended and fixed to the upper end of the second mixer cylinder 11 by the swirl plate extension ring 10.

[0050] The first sleeve 13 and the second sleeve 18 are located between the first long groove 73 and the second long groove 74;

[0051] The waist-shaped hole 71, the swirl fins 72 and the first long groove 73 are all located inside the third mixer cylinder 19, and the second long groove 74 is located inside the second mixer cylinder 11.

[0052] The ammonia nozzle 1 has an injection hole on its side, with a diameter of 0.5-1mm.

[0053] Figure 7The diagram shows the principle of nozzle gas supply. Ammonia is stored in a liquid ammonia cylinder in a high-pressure form. The supply of ammonia is adjusted by adjusting the opening of the hydraulic pump valve. Since the ambient pressure is relatively low after the liquid ammonia is sprayed out of the ammonia nozzle 1, it is rapidly vaporized. The ammonia nozzles sprayed from the side have a large number of holes, and the ammonia conversion response is fast, which facilitates mixing with the tail gas in the premixing zone.

[0054] The swirl plate 9 is provided with small holes 91, semi-circular blades 92 and swirl blades 93, wherein the small holes 91, semi-circular blades 92 and swirl blades 93 are arranged in a ring from the outside to the inside on the swirl plate 9.

[0055] like Figure 3 As shown, the mixing process of the exhaust gas and ammonia in the mixer is divided into four regions: the nozzle isolation plate 5 is set between the waist-shaped hole 71 and the swirl fin 72, and the nozzle isolation plate 5 is seamlessly connected to the mixing chamber 7, so that the left end of the mixing chamber where the nozzle isolation plate 5 is located forms an ammonia premixing zone with the ammonia nozzle 1, which mainly performs a small part of the exhaust gas and pure ammonia for preliminary mixing to form high-concentration ammonia; the mixing chamber between the left side of the swirl fin 72 of the mixing chamber 7 and the nozzle isolation plate 5 is the secondary mixing zone, which mainly introduces high-concentration ammonia into the center of the mixing chamber 7; the remaining area of ​​the mixing chamber 7 to the left of the swirl fin 72 is the main mixing zone, where the mainstream exhaust gas enters the mixing chamber 7 from the first long groove 73 and continuously mixes with the high-concentration ammonia in the center, and the concentration gradually decreases. When it flows to the baffle 8, the mixed airflow is completely blocked because the baffle 8 is seamlessly connected to the mixing chamber 7. The mixed airflow and the baffle 8 interact violently, forcing the mixed airflow to flow out from the second long groove 74. The swirl plate 9 and its downstream area are the tail mixing zone, where ammonia is further mixed to the SCR catalyst.

[0056] like Figure 4 and 8 As shown in -10, Figure 8-10The red area represents high-concentration ammonia gas, and the blue area represents the upstream tail gas from the first mixer cylinder 6. First, liquid ammonia is ejected from the ammonia nozzle 1 and rapidly vaporizes, mixing with the upstream tail gas from the first mixer cylinder 6 in the premixing zone to form a high-concentration ammonia mixture. At this stage, ammonia is the main component, and the high-concentration mixture flows out from the waist-shaped orifice 71 of the mixing chamber 7, indicating the premixing stage. Second, a large amount of mainstream tail gas, due to its larger relative molecular mass than ammonia, more easily enters from the first long groove 73 of the mixing chamber 7, thus forcing the high-concentration ammonia mixture to enter from the swirl fins 72 of the mixing chamber 7. As it flows downstream, the high-concentration ammonia is trapped in the center of the tail gas, indicating the secondary mixing stage. Then, because the tail end of the mixing chamber 7 is sealed by the baffle 8, the sandwiched tail gas is forced to flow out from the second long groove 72 of the mixing chamber 7 under the intense action of the baffle 8. Simultaneously, the ammonia and tail gas further diffuse and merge, indicating the primary mixing stage. Finally, the mixed airflow is further swirled and mixed under the action of swirl plate 9, and flows downstream to SCR to complete the tail mixing. By constructing a premix → secondary mix → main mix → tail mixing structure, the mixing path is extended and the ammonia mixing effect is improved.

[0057] Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. An ammonia mixer, characterized in that, The system includes a first mixer cylinder (6), a second mixer cylinder (11), and a third mixer cylinder (19). A nozzle base (4) is provided on the third mixer cylinder (19), and an ammonia nozzle (1) is installed on the nozzle base (4). One end of a mixing chamber (7) is fixed on the third mixer cylinder (19), and the other end of the mixing chamber (7) extends into the second mixer cylinder (11). The second mixer cylinder (11) and the third mixer cylinder (19) are connected by a first sleeve (13) and a second sleeve (18). The first mixer cylinder (6) is fixed to the upper end of the third mixer cylinder (19), the upper end of the second mixer cylinder (11) is provided with a swirl plate (9), and the lower end of the second mixer cylinder (11) is provided with a mixer end cap (12). A waist-shaped hole (71) is provided on one side wall of the mixing chamber (7) near the ammonia nozzle (1), and a second long groove (74) is provided on the other side wall of the mixing chamber (7) near the second mixer cylinder (11). Swirl fins (72) and a first long groove (73) are arranged sequentially between the waist-shaped hole (71) and the second long groove (74). A nozzle isolation plate (5) is provided between the waist-shaped hole (71) and the swirl fin (72), and the nozzle isolation plate (5) is seamlessly connected to the mixing chamber (7). A baffle (8) is provided at the tail end of the mixing chamber (7). The baffle (8) is located on the rear side of the second long groove (74). The baffle (8) is seamlessly connected to the mixing chamber (7). The ammonia nozzle (1) has injection holes on its side.

2. The ammonia mixer according to claim 1, characterized in that, A heat insulation cotton (2) and a first gasket (3) are provided between the nozzle base (4) and the ammonia nozzle (1).

3. The ammonia mixer according to claim 1, characterized in that, The angle of the swirling fins (72) is 25-40°, which is used to control the swirling effect of high-concentration ammonia gas.

4. The ammonia mixer according to claim 1, characterized in that, The second sleeve (18) is fixed to the third mixer cylinder (19), the first sleeve (13) is fixed to the second mixer cylinder (11) and the mixer end cap (12), the second sleeve (18) is provided with a bushing (17), the first sleeve (13) and the bushing (17) are connected by a clamp (15), and a reinforcing rib (14) and a second gasket (16) are provided in the middle.

5. The ammonia mixer according to claim 1, characterized in that, The swirl plate (9) is extended and fixed to the upper end of the second mixer cylinder (11) by the swirl plate extension ring (10).

6. The ammonia mixer according to claim 1, characterized in that, The first sleeve (13) and the second sleeve (18) are located between the first long groove (73) and the second long groove (74); The waist-shaped hole (71), the swirl fins (72) and the first long groove (73) are all located inside the third mixer cylinder (19), and the second long groove (74) is located inside the second mixer cylinder (11).

7. The ammonia mixer according to claim 1, characterized in that, The diameter of the injection hole is 0.5-1mm.

8. The ammonia mixer according to claim 1, characterized in that, The swirl plate (9) is provided with small holes (91), semi-circular blades (92) and swirl blades (93), which are arranged in a ring from the outside to the inside on the swirl plate (9).

Images