WO2018153162A1

WO2018153162A1 - Tail gas post-treatment apparatus

Info

Publication number: WO2018153162A1
Application number: PCT/CN2017/119329
Authority: WO
Inventors: 王聪; 陈智; 王天宇
Original assignee: 天纳克（苏州）排放系统有限公司
Priority date: 2017-02-22
Filing date: 2017-12-28
Publication date: 2018-08-30
Also published as: CN106640301A

Abstract

Disclosed is a tail gas post-treatment apparatus comprising a first post-treatment carrier assembly (1), a second post-treatment carrier assembly (2) and a mixer assembly (3), wherein the mixer assembly comprises a housing (31), a mixing tube (32) and a partition plate (33) fixed on the periphery of the mixing tube (32).The partition plate (33) partitions the housing (31) into a first space (331) communicating with the first post-treatment carrier assembly (1) and a second space (332) communicating with the second post-treatment carrier assembly (2). The mixing tube (32) comprises at least two first openings (3211) and at least two second openings (3221) respectively located on two sides thereof. The mixer assembly (3) further comprises at least two perforated plates (35, 36) located in the mixing tube (32) and staggered axially along the mixing tube (32).

Description

Exhaust aftertreatment device

The present application claims the priority of the Chinese Patent Application Serial No. JP-A-----------

Technical field

The invention relates to an exhaust gas aftertreatment device, and belongs to the technical field of engine exhaust aftertreatment.

Background technique

Studies have shown that the uniformity of ammonia distribution in the exhaust gas aftertreatment system (eg, selective catalytic reduction system, SCR system) has an important impact on the overall performance and durability of the system. If the ammonia distribution is uneven, it will lead to excessive ammonia in the local area and easy to cause ammonia leakage, while in other thin ammonia regions, the nitrogen oxide (NOx) conversion efficiency is too low. Uneven distribution of ammonia over a long period of time can result in uneven aging of the catalyst, thereby affecting the overall performance of the catalyst. The uneven distribution of urea droplets will cause the local tube wall or mixed structure temperature to be too low to form crystallization. In severe cases, the tail gas pipe will be blocked, resulting in a decrease in engine power performance. In addition, while considering the anti-crystallization ability, how to reduce the back pressure of the system is also a technical problem to be solved.

Summary of the invention

It is an object of the present invention to provide an exhaust gas aftertreatment device which has a better mixing effect.

In order to achieve the above object, the present invention adopts the following technical solution: an exhaust aftertreatment device including a first post-processing carrier assembly, a second post-processing carrier assembly, and the first post-processing carrier assembly and the second rear Processing a mixer assembly between the carrier assemblies, wherein the mixer assembly includes a housing, a mixing tube positioned within the housing, and a baffle secured to a periphery of the mixing tube, the baffle placing the housing Separating into a first space in communication with the first aftertreatment carrier assembly and a second space in communication with the second aftertreatment carrier assembly, the mixing tube including a first tube located within the first space And a second tube portion located in the second space, wherein the first tube portion is provided with at least two first openings respectively located at two sides thereof, and the second tube portion is respectively disposed at two sides thereof At least two second openings, the mixer assembly further comprising at least two perforated plates located within the mixing tube and staggered along an axis of the mixing tube.

As a further improved technical solution of the present invention, the first post-treatment carrier assembly, the second post-treatment carrier assembly, and the mixer assembly are arranged in a straight line.

As a further improved technical solution of the present invention, the housing is provided with a first axis, and the mixing tube is provided with a second axis, the first axis intersecting the second axis.

As a further improvement of the invention, the first axis is perpendicular to the second axis.

As a further improved technical solution of the present invention, the partition plate includes an inclined portion disposed obliquely to the second axis of the mixing tube and an extending portion extending downward from the inclined portion, the extending portion including the abutting portion The curved surface on the mixing tube.

As a further improved technical solution of the present invention, the mixer assembly includes a bowl cover at a bottom of the mixing tube, the bowl cover is fixed at a lower end of the second tube portion, and the bowl cover is provided to the first A circular arc-shaped projection extending in the second tube portion.

As a further improved technical solution of the present invention, the exhaust gas aftertreatment device is provided with a nozzle mounting seat on the casing and used to install a urea nozzle to spray the atomized urea solution into the mixing tube.

As a further improvement of the technical solution of the present invention, the at least two perforated plates comprise a first perforated plate and a second perforated plate, wherein the first perforated plate and the second perforated plate are semicircular The first perforated plate is provided with a plurality of first openings, and the second perforated plate is provided with a plurality of second openings.

As a further improved technical solution of the present invention, the perforated plates are formed into at least one circle as viewed along the axis of the mixing tube.

As a further improved technical solution of the present invention, the first aperture plate is provided with a plurality of first fixing claws fixed on an inner wall of the mixing tube, and the second aperture plate is provided to be fixed in the mixing A plurality of second fixed jaws on the inner wall of the tube.

Compared with the prior art, the present invention enhances the breaking of urea particles by setting at least two perforated plates which are located in the mixing tube and are staggered along the axis of the mixing tube, and also enhances heat exchange and improves mixing. effect.

DRAWINGS

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a perspective view of an exhaust gas aftertreatment device of the present invention.

Figure 2 is a perspective view of another angle of Figure 1.

Fig. 3 is a partially exploded perspective view of Fig. 2;

4 is a partial exploded perspective view of the mixer assembly of FIG. 3.

Figure 5 is a further exploded perspective view of Figure 4.

Figure 6 is a plan view of the mixing tube, the partition, the first perforated plate and the second perforated plate of Figure 4 assembled together.

Fig. 7 is a schematic cross-sectional view taken along line C-C of Fig. 3.

Figure 8 is a schematic cross-sectional view taken along line A-A of Figure 2;

Figure 9 is a cross-sectional view taken along line B-B of Figure 2 .

detailed description

Referring to Figures 1 through 9, the present invention discloses an exhaust aftertreatment device 100 for treating the exhaust of an engine. The exhaust aftertreatment device 100 includes a first aftertreatment carrier assembly 1, a second aftertreatment carrier assembly 2, and a mixer assembly between the first aftertreatment carrier assembly 1 and the second aftertreatment carrier assembly 2 3. In the illustrated embodiment of the invention, the first aftertreatment carrier assembly 1, the second aftertreatment carrier assembly 2, and the mixer assembly 3 are arranged in a straight line. The first aftertreatment carrier assembly 1 includes an oxidation catalyst (DOC) 11 and a diesel particulate filter (DPF) 12 located downstream of the oxidation catalyst 11 . The second post-treatment carrier assembly 2 includes a selective catalytic reduction agent (SCR) 21. The above oxidation catalyst 11, diesel particulate filter 12 and selective catalytic reducing agent 21 are detachably connected by a clamp for maintenance and replacement.

The mixer assembly 3 includes a housing 31, a mixing tube 32 located within the housing 31, a partition 33 fixed to the periphery of the mixing tube 32, a bowl cover 34 at the bottom of the mixing tube 32, and At least two perforated plates are disposed in the mixing tube 32 and staggered along the axis of the mixing tube 32. In the illustrated embodiment of the invention, the at least two apertured plates comprise a first apertured plate 35 and a second apertured plate 36. Referring to FIG. 3, FIG. 7 and FIG. 8, the partition plate 33 partitions the casing 31 into a first space 331 communicating with the first after-treatment carrier assembly 1 and the second rear A second space 332 in which the carrier assembly 2 is in communication is processed. The mixing tube 32 includes a first tube portion 321 located in the first space 331 and a second tube portion 322 located in the second space 332, wherein the first tube portion 321 is respectively disposed at two of the tubes At least two first openings 3211 on the side, the second tube portions 322 are provided with at least two second openings 3221 on opposite sides thereof. The first opening 3211 is for the airflow to enter, and the second opening 3221 is for the airflow to flow to form a double swirling mixing effect.

In the illustrated embodiment of the present invention, the housing 31 has a cylindrical shape and is provided with a first axis 311; the mixing tube 32 has a cylindrical shape, and is provided with a second axis 323, the first The axis 311 intersects the second axis 323. Preferably, the first axis 311 is perpendicular to the second axis 323. Of course, in other embodiments, the housing 31 and the mixing tube 32 may have other shapes, such as an elliptical shape or the like.

The partition 33 includes an inclined portion 333 disposed obliquely to the second axis 323 of the mixing tube 32 and an extending portion 334 extending downward from the inclined portion 333, the extending portion 334 including abutting against the mixing An arcuate surface 335 on the tube 32.

The bowl cover 34 is fixed to the lower end of the second tube portion 322, and the bowl cover 34 is provided with a circular arc-shaped protrusion 341 extending into the second tube portion 322 to guide the reverse flow of the airflow. Passing through the second opening 3221. The bowl lid 34 prevents the urea solution from being directly sprayed onto the exhaust pipe, thereby reducing the risk of urea crystallization.

The exhaust aftertreatment device 100 is provided with a nozzle mount 310 on the housing 31 for mounting a urea nozzle to inject a urea solution after atomization into the mixing tube 32.

In the illustrated embodiment of the present invention, the first perforated plate 35 and the second perforated plate 36 are each semi-circular, and the first perforated plate 35 is provided with a plurality of first openings 351. The second aperture plate 36 is provided with a plurality of second openings 361. Referring to FIG. 6, the first perforated plate 35 and the second perforated plate 36 are formed into at least one circle as viewed along the axis of the mixing tube 32. In the illustrated embodiment of the present invention, the first perforated plate 35 and the second perforated plate 36 are just formed into a circle. Of course, it can be understood that in other embodiments, the first perforated plate 35 and the second perforated plate 36 may have overlapping portions to form more than one circle. In other embodiments, the perforated plate may also be three or more pieces, and at this time, the perforated plates are formed into at least one circle. The first perforated plate 35 is provided with a plurality of first fixing claws 352 for fixing on the inner wall of the mixing tube 32, and the second perforated plate 36 is provided for fixing on the inner wall of the mixing tube 32. A plurality of second fixed jaws 362.

By providing the first perforated plate 35 and the second perforated plate 36, the crushing of the urea particles is enhanced, and the mixing effect is enhanced; in addition, the heat exchange is enhanced, and the formation of crystals due to the local temperature is too low. risk. If it is a one-piece perforated plate, in order to achieve better urea crushing, it is necessary to provide an opening with a smaller pore size, which inevitably leads to a higher back pressure; however, if the back pressure is reduced, the pore size is bound to be enlarged, so that Achieve good fracture of urea. By disposing the first perforated plate 35 and the second perforated plate 36 in a staggered manner, a region S1 through which airflow passes is also formed between them (refer to FIG. 7), thereby reducing back pressure without Affecting the crushing of urea granules, unexpected technical effects have been achieved.

In the illustrated embodiment of the invention, exhaust gas enters the mixing tube 32 from the first opening 3211 as the exhaust of the engine passes through the first aftertreatment carrier assembly 1 into the first space 331. When the injection conditions are satisfied, the urea nozzle injects urea into the mixing tube 32, and the atomized urea droplets are mixed with the exhaust gas of the engine and moved downstream. The first perforated plate 35 and the second perforated plate 36 enhance heat exchange and breakage of urea particles. Referring to the spiral arrow in FIG. 9, then, under the blockage of the bowl cover 34, the airflow is better reversed (eg, upstream); the airflow after the reverse direction passes through the second opening 3221 to form a double Swirl. The gas stream then enters the second space 332 and reaches the second post-treatment carrier assembly 2 located downstream. In this way, by swirling and breaking the urea particles, the distance and time of urea evaporation are increased, the uniformity of gas flow mixing is improved, and the risk of urea crystallization is reduced.

In addition, the above embodiments are only for illustrating the present invention and are not intended to limit the technical solutions described in the present invention. The understanding of the present specification should be based on those skilled in the art, although the present specification has been carried out with reference to the above embodiments. DETAILED DESCRIPTION OF THE INVENTION However, those skilled in the art should understand that the invention may be modified or equivalently replaced by those skilled in the art without departing from the spirit and scope of the invention. It is intended to be included within the scope of the appended claims.

Claims

An exhaust aftertreatment device comprising a first aftertreatment carrier assembly, a second aftertreatment carrier assembly, and a mixer assembly between the first aftertreatment carrier assembly and the second aftertreatment carrier assembly, wherein The mixer assembly includes a housing, a mixing tube located within the housing, and a partition secured to a periphery of the mixing tube, the partition separating the housing into connection with the first aftertreatment carrier assembly a first space and a second space in communication with the second post-processing carrier assembly, the mixing tube including a first tube portion located in the first space and a second portion located in the second space a tube portion, wherein the first tube portion is provided with at least two first openings respectively located at two sides thereof, and the second tube portion is provided with at least two second openings respectively located at two sides thereof, wherein: The mixer assembly also includes at least two perforated plates located within the mixing tube and staggered along the axis of the mixing tube.
The exhaust aftertreatment device of claim 1 wherein said first aftertreatment carrier assembly, said second aftertreatment carrier assembly and said mixer assembly are arranged in a line.
The exhaust aftertreatment device of claim 2 wherein said housing is provided with a first axis and said mixing tube is provided with a second axis, said first axis intersecting said second axis.
The exhaust aftertreatment device of claim 3 wherein said first axis is perpendicular to said second axis.
The exhaust gas aftertreatment device according to claim 3, wherein the partition plate includes an inclined portion that is disposed obliquely to a second axis of the mixing tube, and an extending portion that extends downward from the inclined portion, The extension includes an arcuate surface that abuts against the mixing tube.
The exhaust gas aftertreatment device according to claim 1, wherein said mixer assembly includes a bowl cover at a bottom of said mixing tube, said bowl cover being fixed to a lower end of said second tube portion, said bowl The cover is provided with a circular arc-shaped projection extending into the second tube portion.
The exhaust gas aftertreatment device according to claim 1, wherein the exhaust gas aftertreatment device is disposed on the casing and is configured to install a urea nozzle to spray the atomized urea solution into the mixing pipe. Nozzle mount.
The exhaust gas after-treatment device according to any one of claims 1 to 7, wherein the at least two perforated plates comprise a first perforated plate and a second perforated plate, the first opening The plate and the second perforated plate are each semi-circular, the first perforated plate is provided with a plurality of first openings, and the second perforated plate is provided with a plurality of second openings.
The exhaust gas after-treatment device according to any one of claims 1 to 7, wherein the perforated plates are formed into at least one circle as viewed along the axis of the mixing tube.
The exhaust gas after-treatment device according to claim 8, wherein the first perforated plate is provided with a plurality of first fixing claws fixed on an inner wall of the mixing tube, and the second perforated plate is provided. There are a plurality of second fixing claws for fixing on the inner wall of the mixing tube.