CN111810278A

CN111810278A - Radial injection close-coupled mixing device for mixing reducing agent fluid

Info

Publication number: CN111810278A
Application number: CN201910285177.3A
Authority: CN
Inventors: 郭鑫
Original assignee: Jiangsu Weibo Power Technology Co ltd
Current assignee: Jiangsu Weibo Power Technology Co ltd
Priority date: 2019-04-10
Filing date: 2019-04-10
Publication date: 2020-10-23

Abstract

The invention discloses a radial injection compact lotus root type mixing device for mixing reducing agent fluid, which comprises a cylinder body and a reducing agent injection base, wherein a first rotational flow clapboard, a second rotational flow clapboard and an expansion clapboard are sequentially arranged along the inner wall of the cylinder body from an air inlet end to an air outlet end in the cylinder body, the reducing agent injection base is arranged on the outer wall of the cylinder body and is arranged between the first rotational flow clapboard and the second rotational flow clapboard, a nozzle is arranged on the reducing agent injection base, a first mixing cavity is formed between the first rotational flow clapboard and the second rotational flow clapboard, a second mixing cavity is formed between the second rotational flow clapboard and the expansion clapboard, a plurality of semicircular through holes are arranged on the first rotational flow clapboard, a cylindrical cylinder body structure through hole is arranged at the center position of the second rotational flow clapboard, and the expansion clapboard is provided with the through holes, so that a urea aqueous solution is fully mixed with exhaust tail gas, reduce the crystallization of the urea aqueous solution and avoid corroding the exhaust device.

Description

Radial injection close-coupled mixing device for mixing reducing agent fluid

Technical Field

The invention belongs to the field of diesel engine tail gas aftertreatment, and particularly relates to a radial injection compact coupling type mixing device for mixing reducing agent fluid.

Background

Global legislation on emissions from internal combustion engines is becoming more stringent and it has become difficult to meet the current stringent emission standards by improving the combustion technology of internal combustion engines in itself. Accordingly, exhaust aftertreatment devices have become more prevalent in various internal combustion engine systems, particularly in vehicles that employ internal combustion engines, to further reduce emissions.

A typical vehicle exhaust aftertreatment device useful for reducing nitrogen oxide (NOx) emissions typically includes a mixing device for mixing the exhaust gas with a reductant fluid and a reaction device downstream thereof to promote a reduction reaction of nitrogen oxides in the exhaust gas.

In the industry, the reaction device is typically a Selective Catalytic Reduction (SCR) device, in which an SCR catalyst is disposed to promote reduction of nitrogen oxides in the exhaust gas. For example, in the case where the reducing agent fluid is an aqueous urea solution, the aqueous urea solution is injected into the mixing device and then mixed with the exhaust gas having a relatively high temperature, and hydrolysis/pyrolysis reaction is performed to generate ammonia gas; after the mixed fluid of ammonia and exhaust gas flows into the SCR device, nitrogen oxides in the exhaust gas can generate reduction reaction with the ammonia gas to generate nitrogen and water which are harmless to the environment.

In most mixing devices of the prior art, urea fluid is injected into the exhaust stream in a radial injection manner to mix with each other. The term "radial injection mode" as used herein refers to injection of the treatment fluid into the mixing device in a direction substantially perpendicular to the direction of travel of the exhaust gas to mix with the exhaust gas.

However, due to the limited spatial arrangement of the current N1-type vehicles, in this fluid injection manner, the following may be caused:

the mixing distance of the urea aqueous solution is short, and the urea aqueous solution cannot be fully mixed;

the urea aqueous solution is not sufficiently hydrolyzed/pyrolyzed into NH3 by being sprayed into the exhaust pipe, resulting in insufficient reaction and ineffective reduction of nitrogen oxides (NOx);

the aqueous urea solution quickly contacts the housing of the exhaust, forming crystals that further cause corrosion and failure of the exhaust.

Disclosure of Invention

The invention aims to solve the defects in the existing exhaust aftertreatment technology of N1 vehicles, and provides a radial injection close-coupled mixing device for mixing reducing agent fluid, which is fully mixed with the reducing agent fluid injected in the radial direction, improves the uniformity of the reducing agent, fully reacts nitrogen oxides, and further reduces the pollutants discharged by automobiles.

The purpose of the invention can be realized by the following technical scheme:

a radial injection compact lotus root type mixing device for mixing reducing agent fluid comprises a barrel body 2 and a reducing agent injection base 4, wherein a first rotational flow partition plate 1, a second rotational flow partition plate 3 and an expansion partition plate 5 are sequentially arranged from an air inlet end to an air outlet end in the barrel body 2 along the inner wall of the barrel body 2, the reducing agent injection base 4 is arranged on the outer wall of the barrel body 2, the reducing agent injection base 4 is arranged between the first rotational flow partition plate 1 and the second rotational flow partition plate 3, a nozzle 6 is arranged on the reducing agent injection base 4, a first mixing cavity 7 is formed between the first rotational flow partition plate 1 and the second rotational flow partition plate 3, a second mixing cavity 8 is formed between the second rotational flow partition plate 3 and the expansion partition plate 5, a plurality of semicircular through holes 1.1 are formed in the first rotational flow partition plate 1, and a cylindrical barrel structure through hole is arranged at the center of the second rotational flow, the expansion partition plate 5 is provided with a through hole.

Preferably, a hemispherical wall plate 1.2 is arranged at the lower end of each semicircular through hole 1.1 on the inner wall of the first cyclone partition plate 1.

More preferably, a semi-circular umbrella-shaped guide plate 1.3 which enables airflow to rotate to flow into the first mixing cavity 7 is arranged outside the semi-circular through hole 1.1.

More preferably, the semicircular through holes 1.1 are uniformly arranged along the circumferential direction of the first cyclone barrier 1.

Preferably, the second cyclone partition 3 is conical and is arranged to be closely attached to the inner wall of the cylinder 2.

Preferably, one reducing agent injection base 4 is provided, and a nozzle 6 is provided on the reducing agent injection base 4.

Preferably, the expansion partition 5 is provided with four long waist-shaped holes 5.1 uniformly along the circumferential direction, and nine air holes 5.2 are provided at the central position.

The invention has the beneficial effects that:

the mixing device increases the mixing distance of the urea aqueous solution, so that the urea aqueous solution is fully mixed with the exhaust tail gas; the urea aqueous solution is fully hydrolyzed/pyrolyzed into NH3, nitrogen oxides (NOx) are reduced, the emission of the NOx is reduced, and the requirements of emission regulations are met; the urea aqueous solution is brought away by the rotational flow airflow at the moment of contacting the shell of the exhaust device, so that the crystallization is reduced, and the corrosion to the exhaust device is avoided.

Drawings

FIG. 1 is a schematic cross-sectional view of a radial injection close-coupled mixing device for mixing reductant fluid.

FIG. 2 is a schematic cross-sectional view of a radial injection close-coupled mixing device for mixing reductant fluid.

Fig. 3 is a schematic structural view of the first cyclone barrier.

Fig. 4 is a schematic structural view of the second cyclone barrier.

Fig. 5 is a schematic view of the structure of the expanded baffle.

In the figure, the arrows indicate the direction of air flow.

Detailed Description

The technical scheme of the invention is further described by combining the attached drawings:

In this embodiment, preferably, a hemispherical wall plate 1.2 is provided at the lower end of each semicircular through hole 1.1 on the inner wall of the first cyclone barrier 1.

In this embodiment, it is more preferable that a semicircular umbrella-shaped deflector 1.3 is arranged outside the semicircular through hole 1.1 to make the airflow rotate and flow into the first mixing chamber 7.

In this embodiment, it is more preferable that the semicircular through holes 1.1 are uniformly arranged along the circumferential direction of the first cyclone barrier 1.

In this embodiment, it is more preferable that the second cyclone barrier 3 is conical and is disposed in close contact with the inner wall of the cylinder 2.

In this embodiment, it is preferable that one reducing agent injection base 4 is provided, and a nozzle 6 is provided on the reducing agent injection base 4.

In this embodiment, preferably, the expansion partition 5 is provided with four long waist-shaped holes 5.1 uniformly along the circumferential direction, and nine air holes 5.2 at the central position.

The reductant fluid is thoroughly mixed with the exhaust gas within the mixing device to ensure that the reductant in gaseous form is evenly distributed in the exhaust device and that the mixing device has a relatively small pressure drop to avoid excessive back pressure.

This device air inlet front end is for having the first whirl baffle 1 of whirl effect, makes exhaust flow into first mixing chamber 7 with the rotation form, forms stronger rotatory air current, and reductant fluid directly spouts first mixing chamber 7, rotates along second whirl baffle 3, accelerates the pyrolysis/hydrolysis of reductant, and the mixing effect is splendid.

The rotational flow airflow of the first mixing chamber 7 enables the sprayed reducing agent solution to have a speed of flowing along the airflow direction, so that the reducing agent solution is easier to be taken away by the airflow, and the risk of crystallization of the mixer device is reduced; the second mixing chamber 8 is also a chamber with a stronger swirling flow effect, and the mixing effect is enhanced again; the center of the second cyclone partition plate 3 is provided with a through hole with a cylindrical barrel structure, so that the pressure drop of the mixing device can be reduced; the expansion partition plate 5 helps the diffusion of the mixed gas, increases the uniformity of the reducing agent, is beneficial to the full reaction of the nitrogen oxide, improves the reaction efficiency and ensures the efficient and stable work of the SCR;

compared with other axial injection devices, the device has compact structure and convenient installation.

Finally, it should be noted that:

the method may be carried out and its application may be carried out by those skilled in the art with reference to the disclosure herein, and it is expressly intended that all such alternatives and modifications as would be apparent to those skilled in the art are deemed to be included within the invention. While the method and application of the present invention have been described in terms of preferred embodiments, it will be apparent to those of ordinary skill in the art that variations and modifications in the method and application of the invention as described herein may be made and equivalents employed without departing from the spirit and scope of the invention.

Claims

1. A radial injection close-coupled mixing device for mixing reductant fluid, characterized by:

comprises a cylinder body (2), a reducing agent injection base (4), wherein a first cyclone partition plate (1), a second cyclone partition plate (3) and an expansion partition plate (5) are sequentially arranged from an air inlet end to an air outlet end in the cylinder body (2) along the inner wall of the cylinder body (2), the reducing agent injection base (4) is arranged on the outer wall of the cylinder body (2), the reducing agent injection base (4) is arranged between the first cyclone partition plate (1) and the second cyclone partition plate (3), a nozzle (6) is arranged on the reducing agent injection base (4), a first mixing cavity (7) is formed between the first cyclone partition plate (1) and the second cyclone partition plate (3), a second mixing cavity (8) is formed between the second cyclone partition plate (3) and the expansion partition plate (5), a plurality of semicircular through holes (1.1) are formed in the first cyclone partition plate (1), and a cylindrical cylinder structure through hole is arranged at the center of the second cyclone partition plate (3), the expansion partition plate (5) is provided with a through hole.

2. A radial injection close-coupled mixing device for mixing reductant fluid as defined in claim 1, wherein: and a hemispherical wall plate (1.2) is arranged at the lower end of each semicircular through hole (1.1) on the inner wall of the first cyclone partition plate (1).

3. A radial injection close-coupled mixing device for mixing reductant fluid as defined in claim 2, wherein: a semi-circular umbrella-shaped guide plate (1.3) which enables airflow to rotate to flow into the first mixing cavity (7) is arranged outside the semi-circular through hole (1.1).

4. A radial injection close-coupled mixing device for mixing reductant fluid as defined in claim 3, wherein: the semicircular through holes (1.1) are uniformly arranged along the circumferential direction of the first cyclone partition plate (1).

5. A radial injection close-coupled mixing device for mixing reductant fluid as defined in claim 1, wherein: the second rotational flow partition plate (3) is in a conical shape and is arranged close to the inner wall of the barrel body (2).

6. A radial injection close-coupled mixing device for mixing reductant fluid as defined in claim 1, wherein: the reducing agent injection base (4) is provided with one, and the reducing agent injection base (4) is provided with a nozzle (6).

7. A radial injection close-coupled mixing device for mixing reductant fluid as defined in claim 1, wherein: four long waist-shaped holes (5.1) are uniformly arranged on the expansion partition plate (5) along the circumferential direction, and nine air holes (5.2) are arranged at the central position.