CN217652809U

CN217652809U - Urea solution mixer and engine post-treatment system

Info

Publication number: CN217652809U
Application number: CN202221805593.5U
Authority: CN
Inventors: 薛裕丹; 李健巍; 张晓丽; 张超
Original assignee: Weichai Power Co Ltd
Current assignee: Weichai Power Co Ltd
Priority date: 2022-07-13
Filing date: 2022-07-13
Publication date: 2022-10-25
Anticipated expiration: 2032-07-13

Abstract

The utility model relates to an engine aftertreatment technical field discloses a urea solution blender and engine aftertreatment system, at engine during operation, high temperature tail gas passes through in the inlet port gets into tail gas channel, the urea nozzle passes through the toper opening and sprays urea in to mixing channel simultaneously, high temperature tail gas passes through the opening end of tail gas channel and gets into in the toper open-ended marginal zone from toper open-ended big footpath end opening, and realize the mixture of urea and high temperature tail gas in toper opening and mixing channel, can avoid toper open-ended marginal zone to form the backward flow blind spot, atomization effect has not only been improved, can also avoid toper open-ended inner wall to form the urea crystallization.

Description

Urea solution mixer and engine post-treatment system

Technical Field

The utility model relates to an engine aftertreatment technical field especially relates to a urea solution mixer and engine aftertreatment system.

Background

Selective Catalytic Reduction (SCR) refers to a technique for reducing NOx in flue gas selectively to non-toxic N2 and H2O by using a reducing agent (ammonia, urea, hydrocarbon, etc.) under a certain temperature range and a catalyst.

The catalyst is the most critical part of the SCR system, and the activity of the catalyst is a measure of the rate at which the catalyst accelerates the NOx reduction reaction. The higher the activity of the catalyst is, the faster the reaction rate is, the higher the efficiency of removing NOx is, and the activity of the catalyst is affected by the components of the catalyst, the urea solution mixer which evaporates the urea solution and mixes with air, the flue gas temperature, the flue gas components and other factors.

For the current urea solution mixer, the urea solution mixer comprises a nozzle mounting seat, a urea nozzle and a mixing pipeline, wherein a mounting channel is arranged on the nozzle mounting seat, one end of the urea nozzle is inserted into the mounting channel, the mixing pipeline is mounted on the nozzle mounting seat, and one end of the mixing pipeline is communicated with the other end of the mounting channel. The urea nozzle sprays urea and sprays into the mixing pipeline from the installation channel, and simultaneously the high-temperature tail gas of the engine is introduced into the mixing pipeline from the circumferential side wall of the mixing pipeline, and the high-temperature tail gas and the urea are mixed to form urea spray.

However, in actual operation, the installation channel and the mixing pipeline are coaxial, urea is sprayed into the mixing pipeline along the axial direction of the installation channel, and high-temperature tail gas is introduced into the mixing pipeline from the circumferential side wall of the mixing pipeline. A small amount of high-temperature tail gas overflows from the edge part of one end of the mixing pipeline close to the urea nozzle and directly impacts the urea nozzle, so that the urea nozzle is easily damaged by high-temperature waste gas. For this purpose, it is proposed to provide a divergent cone opening at the end of the installation channel adjoining the mixing duct, so that the high-temperature exhaust gases which overflow from the edge of the mixing duct at the end close to the urea nozzle enter the edge region of the cone opening without directly impacting the urea nozzle.

However, in practical applications, it is found that after the tapered opening is provided, backflow is easily generated in the edge area of the tapered opening, so that urea droplets with small particle size form urea crystals on the inner surface of the tapered opening, and when the urea crystals are serious, the urea spray cone angle and the urea atomization effect are affected, and even the spray hole of the urea nozzle is blocked.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a urea solution blender and engine aftertreatment system can avoid the air current to form the urea crystallization at the internal surface of nozzle mount pad.

To achieve the purpose, the utility model adopts the following technical proposal:

a urea solution mixer comprises a nozzle mounting seat, wherein a mounting channel for mounting a urea nozzle is arranged on the nozzle mounting seat, and one end of the mounting channel is a gradually-expanded conical opening;

still include the water conservancy diversion structure, the water conservancy diversion structure includes:

the inner guide sleeve is provided with a mixing channel extending along the axial direction of the inner guide sleeve, and one end of the mixing channel is communicated with the conical opening;

the outer diversion sleeve is sleeved outside the inner diversion sleeve, an air inlet is formed in the outer diversion sleeve, a tail gas channel communicated with the air inlet is formed between the outer diversion sleeve and the inner diversion sleeve, and one end of the tail gas channel is opened and is directly communicated with the large-diameter end opening of the conical opening.

As a preferable technical solution of the urea solution mixer, the mounting channel includes a mounting hole, and the mounting hole is coaxial with the tapered opening and is connected with the large-diameter end of the tapered opening to form a step surface; one end of the outer flow guide sleeve is inserted into the mounting hole and is abutted to the step surface.

As a preferable technical solution of the urea solution mixer, the outer flow guide sleeve is an annular structure, and the inner diameter of the outer flow guide sleeve is greater than or equal to the diameter of the large-diameter end of the conical opening.

As a preferred technical scheme of the urea solution mixer, the urea solution mixer further comprises a connecting sheet, and the inner guide sleeve and the outer guide sleeve are connected through the connecting sheet.

As a preferable technical scheme of the urea solution mixer, the connecting pieces are provided in plurality, and the connecting pieces are circumferentially arranged at intervals along the inner flow guide sleeve.

As an optimal technical scheme of the urea solution mixer, the connecting sheet is located in the tail gas channel, the connecting sheet divides the tail gas channel into a plurality of branch flow channels which are circumferentially distributed in sequence, the connecting sheet is provided with communicating holes, and two adjacent branch flow channels are communicated through the communicating holes.

As a preferred technical solution of the above urea solution mixer, an end surface of the outer flow guide sleeve facing away from the tapered opening is recessed with a slot, and the slot penetrates through an inner peripheral wall and an outer peripheral wall of the outer flow guide sleeve to form the air inlet.

As a preferable technical solution of the urea solution mixer, a slot is formed in an inner bottom wall of the slot, and one end of the connecting piece is inserted into the slot.

As a preferred technical solution of the above urea solution mixer, the inner flow guide sleeve is a conical ring.

The utility model also provides an engine post-treatment system, which comprises a urea nozzle and the urea solution mixer in any scheme; one end of the urea nozzle is inserted into and fixed in the mounting channel, and the urea nozzle is used for spraying urea into the mixing channel through the conical opening.

The utility model discloses beneficial effect: the utility model provides a urea solution blender and engine aftertreatment system, at engine during operation, high temperature tail gas passes through in the inlet port gets into tail gas channel, the urea nozzle passes through the toper opening and sprays urea in to the hybrid channel simultaneously, high temperature tail gas passes through the opening end of tail gas channel and gets into in the toper open-ended marginal zone from toper open-ended big footpath end opening, and realize the mixture of urea and high temperature tail gas in toper opening and hybrid channel, can avoid toper open-ended marginal zone to form the backward flow blind spot, atomization effect has not only been improved, can also avoid toper open-ended inner wall to form the urea crystallization.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required to be used in the description of the embodiments of the present invention will be briefly described below, and it is obvious that the drawings in the description below are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the contents of the embodiments of the present invention and the drawings without creative efforts.

FIG. 1 is a cross-sectional view of a urea solution mixer provided by an embodiment of the present invention

Fig. 2 is a front view of a flow guiding structure provided by the embodiment of the present invention;

fig. 3 is a top view of a flow guiding structure according to an embodiment of the present invention.

In the figure:

1. a flow guide structure; 11. an inner flow guide sleeve; 111. a mixing channel; 12. an outer flow guide sleeve; 121. slotting; 13. connecting sheets; 131. a communicating hole; 14. a tail gas channel; 2. a nozzle mount; 21. a tapered opening; 22. and (7) assembling holes.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be further noted that, for the convenience of description, only some of the structures related to the present invention are shown in the drawings, not all of the structures.

In the description of the present invention, unless expressly stated or limited otherwise, the terms "connected," "connected," and "fixed" are to be construed broadly, e.g., as meaning permanently connected, detachably connected, or integral to one another; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or may be connected through the use of two elements or the interaction of two elements. The specific meaning of the above terms in the present invention can be understood as a specific case by those skilled in the art.

In the present application, unless expressly stated or limited otherwise, the recitation of a first feature "on" or "under" a second feature may include the recitation of the first and second features being in direct contact, and may also include the recitation of the first and second features not being in direct contact, but being in contact with another feature between them. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly under and obliquely below the second feature, or simply meaning that the first feature is at a lesser elevation than the second feature.

In the description of the present embodiment, the terms "upper", "lower", "right", and the like are used based on the orientations and positional relationships shown in the drawings, and are only for convenience of description and simplification of operation, but do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used only for descriptive purposes and are not intended to have a special meaning.

As shown in fig. 1 to 3, the present embodiment provides a urea solution mixer and an engine aftertreatment system, wherein the engine aftertreatment system includes a urea nozzle and a urea solution mixer, the urea solution mixer includes a nozzle mounting seat 2 and a flow guide structure 1, an installation channel is disposed on the nozzle mounting seat 2, one end of the urea nozzle is inserted into and fixed to the installation channel, the urea nozzle is configured to inject a urea solution into the flow guide structure 1 through the other end of the installation channel, and the flow guide structure 1 is configured to mix the urea solution injected into the urea nozzle with a high-temperature exhaust gas generated by the operation of an engine, so as to atomize urea.

In order to prevent the urea nozzle from being damaged due to the direct impact of the high-temperature exhaust gas on the urea nozzle, a tapered opening 21 is formed at one end of the installation passage. The flow guide structure 1 comprises an inner flow guide sleeve 11 and an outer flow guide sleeve 12 sleeved outside the inner flow guide sleeve 11, wherein a mixing channel 111 extending along the axial direction of the inner flow guide sleeve 11 is arranged on the inner flow guide sleeve 11, and one end of the mixing channel 111 is communicated with a conical opening 21; an air inlet is arranged on the outer flow guide sleeve 12, a tail gas channel 14 communicated with the air inlet is formed between the inner flow guide sleeve 11 and the outer flow guide sleeve 12, and one end of the tail gas channel 14 is arranged in an open mode and is directly communicated with the large-diameter end opening of the conical opening 21.

When the engine works, high-temperature tail gas enters the tail gas channel 14 through the air inlet hole, the urea nozzle sprays urea into the mixing channel 111 through the conical opening 21, the high-temperature tail gas enters the edge area of the conical opening 21 from the large-diameter end opening of the conical opening 21 through the opening end of the tail gas channel 14, the urea and the high-temperature tail gas are mixed in the conical opening 21 and the mixing channel 111, a backflow dead zone can be prevented from being formed in the edge area of the conical opening 21, urea crystallization is prevented from being formed on the inner wall of the conical opening 21, and the atomization effect is further improved.

Optionally, the outer flow guiding sleeve 12 is fixedly installed on the nozzle mounting base 2, specifically, the installation channel includes a conical opening 21 and an installation hole, the installation hole is coaxial with the conical opening 21 and connected with the large-diameter end of the conical opening 21 and is formed with a step surface, and the outer flow guiding sleeve 12 is inserted into the installation hole and abuts against the step surface. In this embodiment, one end of the outer flow guiding sleeve 12 is inserted into and welded and fixed in the mounting hole. The outer guide sleeve 12 is of a columnar structure, the inner diameter of the outer guide sleeve 12 is larger than or equal to the diameter of the large-diameter end of the conical opening 21, and an air flow dead zone can be effectively prevented from being formed at the position where the axial end face of the outer guide sleeve 12 is connected with the inner wall of the conical opening 21. Preferably, the inner diameter of outer guide sleeve 12 is equal to the diameter of the larger diameter end of conical opening 21.

The mounting channel further comprises a mounting hole 22 connected to the small diameter end of the conical opening 21 and coaxial with said conical opening 21, the mounting hole 22 being used for mounting a urea nozzle. How the urea nozzle is fixed to the nozzle mount 2 is prior art in the field and is not described herein in detail.

In this embodiment, the conical opening 21 and the mixing channel 111 are coaxially arranged, so that the exhaust gas discharged from the exhaust gas channel 14 flows from the edge area of the conical opening 21 to the center of the conical opening 21, and enters the mixing channel 111 together with urea, thereby effectively preventing the inner wall of the conical opening 21 from forming urea crystals.

Optionally, the inner flow guide sleeve 11 is a conical ring, and the outer conical surface of the inner flow guide sleeve 11 is used for guiding the high-temperature tail gas so that the high-temperature tail gas is sprayed out from the small-diameter end along the outer conical surface of the inner flow guide sleeve 11 and meets the counter-flow urea, so that the flow disturbing effect is good, the atomization effect of the urea is greatly improved, and the urea is prevented from crystallizing and blocking the nozzle.

Furthermore, the end surface of the outer flow guide sleeve 12, which is back to the tapered opening 21, is recessed with a slot 121, and the slot 121 penetrates through the inner and outer peripheral walls of the outer flow guide sleeve 12 to form an air inlet, so that the processing mode is simple and the cost is low.

Further, in order to realize the connection between the inner guide sleeve 11 and the outer guide sleeve 12, the urea solution mixer further comprises a connecting piece 13, and the inner guide sleeve 11 and the outer guide sleeve 12 are connected through the connecting piece 13. In this embodiment, the connecting piece 13 is welded and fixed to the inner flow guide sleeve 11 and the outer flow guide sleeve 12.

Optionally, a slot is formed in an inner bottom wall of the slot 121, and one end of the connecting piece 13 is inserted into the slot to improve the stability of the connection between the inner flow guide sleeve 11 and the outer flow guide sleeve 12.

Optionally, the connecting pieces 13 are provided in plurality, and the connecting pieces 13 are arranged along the circumferential direction of the inner flow guide sleeve 11 at intervals, so that the connection stability of the inner flow guide sleeve 11 and the outer flow guide sleeve 12 is improved.

Optionally, the connecting sheet 13 is located in the exhaust gas channel 14, the plurality of connecting sheets 13 divide the exhaust gas channel 14 into a plurality of branch runners which are circumferentially distributed in sequence, the connecting sheet 13 is provided with a communicating hole 131, and two adjacent branch runners are communicated through the communicating hole 131, so that the connecting sheet 13 has a turbulent flow effect, and the mixing effect of the high-temperature exhaust gas and the urea is improved.

The urea solution mixer provided by the embodiment can be applied to engines with different discharge capacities, the size of the flow guide structure 1 can be reasonably adjusted according to the post-treatment requirements of different specifications, the matching with the discharge capacity of the engine is realized, and the urea solution mixer is simple in structure, low in cost and high in reliability.

In addition, the foregoing is only a preferred embodiment of the present invention and the technical principles applied thereto. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail with reference to the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the scope of the present invention.

Claims

1. A urea solution mixer comprises a nozzle mounting seat (2), wherein a mounting channel for mounting a urea nozzle is arranged on the nozzle mounting seat (2), and one end of the mounting channel is provided with a tapered opening (21);

the utility model is characterized in that, still include water conservancy diversion structure (1), water conservancy diversion structure (1) includes:

the inner guide sleeve (11) is provided with a mixing channel (111) extending along the axial direction of the inner guide sleeve (11), and one end of the mixing channel (111) is communicated with the conical opening (21);

outer water conservancy diversion cover (12), outer water conservancy diversion cover (12) cover is located outside interior water conservancy diversion cover (11), be equipped with the inlet port on outer water conservancy diversion cover (12), outer water conservancy diversion cover (12) with form between interior water conservancy diversion cover (11) with tail gas channel (14) of inlet port intercommunication, the uncovered setting of one end of tail gas channel (14) and with the big footpath end opening of toper opening (21) directly communicates.

2. A urea solution mixer according to claim 1, characterized in that the mounting channel comprises a mounting hole coaxial with the conical opening (21) and forming a step surface in connection with the large diameter end of the conical opening (21); one end of the outer flow guide sleeve (12) is inserted into the mounting hole and is abutted to the step surface.

3. Urea solution mixer according to claim 2, characterized in that the outer flow guiding sleeve (12) is an annular structure, the inner diameter of the outer flow guiding sleeve (12) being equal to or larger than the large diameter end aperture of the conical opening (21).

4. A urea solution mixer according to claim 1, further comprising a connecting piece (13), wherein the inner guide sleeve (11) and the outer guide sleeve (12) are connected by means of the connecting piece (13).

5. A urea solution mixer according to claim 4, characterised in that the connection piece (13) is provided in a plurality, said connection pieces (13) being arranged circumferentially at intervals along the inner flow guiding sleeve (11).

6. A urea solution mixer according to claim 5, characterized in that said connection piece (13) is located inside said exhaust channel (14), said connection piece (13) divides said exhaust channel (14) into a plurality of branch channels circumferentially distributed in turn, said connection piece (13) is provided with communication holes (131), and two adjacent branch channels are communicated through said communication holes (131).

7. Urea solution mixer according to claim 4, characterized in that the end surface of the outer flow guiding sleeve (12) facing away from the conical opening (21) is recessed with a slot (121), which slot (121) penetrates the inner and outer circumferential wall of the outer flow guiding sleeve (12) forming the inlet opening.

8. Urea solution mixer according to claim 7, characterized in that the inner bottom wall of the slot (121) is provided with a slot into which one end of the connection piece (13) is plugged.

9. Urea solution mixer according to any of the claims 1-6, characterized in that the inner flow guiding sleeve (11) is a conical ring.

10. An engine aftertreatment system comprising a urea nozzle and a urea solution mixer according to any one of claims 1 to 9; one end of the urea nozzle is inserted into and fixed in the mounting channel, and the urea nozzle is used for spraying urea into the mixing channel (111) through the conical opening (21).