CN104948272A - SCR (selective catalytic reduction) system and urea ejection nozzle thereof - Google Patents

Abstract

The invention discloses a urea nozzle of an SCR system, comprising a nozzle body, a nozzle core and a nozzle cover, the front end of the nozzle body has nozzle holes and air holes, and the nozzle cover cooperates with the rear end of the nozzle body to fix the nozzle core on the nozzle In the body, the urea channel of the nozzle core communicates with the urea inlet and the nozzle hole; the side of the nozzle body has a gas inlet, and the side of the nozzle core and the nozzle body has a first gas channel, and the first gas channel communicates with the gas inlet and the air hole; the front end of the nozzle core The mating surface inside the front end surface of the nozzle body has a second gas channel, and the second gas channel communicates with the first gas channel and the injection hole. When the urea nozzle is working, the urea solution and a part of the gas are ejected from the nozzle hole at the same time, which enhances the atomization effect of the urea solution, and the other part of the gas is ejected from the air hole to form a gas barrier on the front side of the nozzle body to avoid the formation of crystals on the nozzle body , to avoid the nozzle body being blocked. The invention also discloses an SCR system.

Description

A kind of SCR system and its urea nozzle

technical field

The invention relates to the technical field of engine exhaust emissions, in particular to an SCR system and a urea spray nozzle.

Background technique

SCR technology (Selective Catalytic Reduction Technology) is mostly used in the exhaust gas treatment of diesel engines to catalytically reduce nitrogen oxides emitted by diesel engines into nitrogen and water.

The engine exhaust gas flows out of the turbocharger turbine and enters the exhaust pipe. At the same time, a certain amount of urea aqueous solution is sprayed into the exhaust pipe by the urea nozzle installed on the exhaust pipe. The urea droplets are hydrolyzed and pyrolyzed under the action of high-temperature exhaust gas. reaction to generate the required reducing agent ammonia (NH3), and the ammonia will selectively reduce nitrogen oxides (NOx) to nitrogen (N2) and water under the action of a catalyst.

At present, the urea nozzle in the SCR system includes a channel and a nozzle hole. The urea flows through the channel and is sprayed out from the nozzle hole. A urea spray will be formed around the nozzle. The urea spray is easy to crystallize on the nozzle, block the nozzle, and affect the use of the urea nozzle.

Therefore, how to avoid the formation of urea crystals on the urea nozzle and avoid blocking the nozzle is a technical problem urgently needed by those skilled in the art.

Contents of the invention

The object of the present invention is to provide a urea spray head of an SCR system, which can avoid urea crystallization and blockage. Another object of the present invention is to provide an SCR system having the above urea spray head.

In order to achieve the above-mentioned technical purpose, the present invention provides a urea spray head of an SCR system, which includes a spray head body, a spray head core, and a spray head cover. The front end of the spray head body has nozzle holes and air holes. The rear end cooperates to fix the nozzle core in the nozzle body, and the urea channel of the nozzle core communicates with the urea inlet and the nozzle hole; the side of the nozzle body has a gas inlet, and the nozzle core and the nozzle The matching side of the nozzle body has a first gas channel, and the first gas channel communicates with the gas inlet and the air hole; the matching surface between the front end of the nozzle core and the inside of the front end surface of the nozzle body has a second gas channel, The second gas channel communicates with the first gas channel and the nozzle hole.

Preferably, the nozzle hole is located in the middle of the front end face of the shower head body, and a plurality of the air holes are evenly distributed around the front end face of the shower head body.

Preferably, the matching surface between the front end of the nozzle core and the inside of the front end of the nozzle body is a conical surface.

Preferably, the outer side of the diverging end of the conical surface has a first annular air chamber, a plurality of the air holes are distributed on the first annular air chamber; a plurality of the second gas channels are distributed on the conical surface , communicating with the first annular air chamber and the nozzle hole.

Preferably, there is a second annular air chamber at the rear of the side where the nozzle core cooperates with the nozzle body, the gas inlet is located on the side of the second annular air chamber, and the first gas channel communicates with the first air chamber. An annular air chamber and the second annular air chamber.

Preferably, a plurality of the first gas channels are distributed on the side of the shower core.

Preferably, the number of the first gas channel and the number of the second gas channel are four.

Preferably, the nozzle cover has a through hole, the rear end of the nozzle core passes through the through hole, and the urea inlet is located at the rear end of the nozzle core.

The present invention also provides an SCR system, including a urea tank, a urea pump, and a urea spray head, the urea pump pumps the urea solution in the urea tank to the urea spray head, and the urea spray head is any one of the above The urea nozzle.

The invention provides a urea spray head of an SCR system, comprising a nozzle body, a nozzle core and a nozzle cover. In the body, the urea channel of the nozzle core communicates with the urea inlet and the nozzle hole; the side of the nozzle body has a gas inlet, and the side of the nozzle core and the nozzle body has a first gas channel, and the first gas channel communicates with the gas inlet and the air hole; the front end of the nozzle core The mating surface inside the front end surface of the nozzle body has a second gas channel, and the second gas channel communicates with the first gas channel and the injection hole.

When the urea nozzle is working, the urea solution enters from the urea inlet, passes through the urea channel of the nozzle core, reaches the nozzle hole, and sprays out from the nozzle hole. At the same time, the gas enters from the gas inlet, and a part passes through the first gas channel and the second gas channel. Enter the nozzle hole and spray out together with the urea solution to further atomize the urea solution; the other part enters the air hole through the first gas channel and is sprayed directly to form a gas barrier on the front side of the nozzle body to avoid crystallization on the nozzle body and avoid The nozzle body is blocked.

Specifically, the nozzle hole is located in the middle of the front end face of the shower head body, and a plurality of air holes are evenly distributed around the front end face of the shower head body. Gas is ejected from the pores of this structure, which can form a gas barrier on the front side of the shower head body.

The present invention also provides an SCR system, including the above-mentioned urea spray head. The urea spray head has the above-mentioned technical effects, so the SCR system with the urea spray head also has corresponding technical effects.

Description of drawings

Fig. 1 is a structural representation of a specific embodiment of a urea spray nozzle provided by the present invention;

Fig. 2 is the bottom view of the urea nozzle shown in Fig. 1;

Fig. 3 is a schematic structural view of the nozzle core of the urea nozzle shown in Fig. 1;

FIG. 4 is a bottom view of the nozzle core shown in FIG. 3 .

Wherein, the corresponding relationship between the reference numerals and the part names in Fig. 1 to Fig. 4 is as follows:

Nozzle cover 1; nozzle body 2; gas inlet 3; nozzle core 4; nozzle hole 5; air hole 6; urea inlet 7; first gas channel 8; second gas channel 9.

Detailed ways

The core of the present invention is to provide a urea nozzle for an SCR system, which can avoid urea crystallization and blockage. Another core of the present invention is to provide an SCR system with the above urea spray head.

In order to enable those skilled in the art to better understand the solution of the present invention, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

Please refer to Figures 1 to 4, Figure 1 is a schematic structural view of a specific embodiment of the urea spray head provided by the present invention, Figure 2 is a bottom view of the urea spray head shown in Figure 1, and Figure 3 is the urea spray head shown in Figure 1 A schematic structural view of the nozzle core of the nozzle, and FIG. 4 is a bottom view of the nozzle core shown in FIG. 3 .

In a specific embodiment, the present invention provides a urea spray head for an SCR system, including a spray head body 2, a spray head core 4, and a spray head cover 1. The front end of the spray head body 2 has spray holes 5 and air holes 6, and the spray head cover 1 Cooperate with the rear end of the nozzle body 2, fix the nozzle core 4 in the nozzle body 2, the urea channel of the nozzle core 4 communicates with the urea inlet 7 and the nozzle hole 5; the side of the nozzle body 2 has a gas inlet 3, the nozzle core 4 and the nozzle The matching side of the body 2 has a first gas channel 8, and the first gas channel 8 communicates with the gas inlet 3 and the gas hole 6; the matching surface between the front end of the nozzle core 4 and the inside of the front end of the nozzle body 2 has a second gas channel 9, and the second The gas channel 9 communicates with the first gas channel 8 and the nozzle hole 5 .

The SCR system includes a urea tank, a urea pump, and a urea nozzle. The urea pump pumps the urea solution in the urea tank to the urea nozzle. The urea solution enters the urea nozzle from the urea inlet 7, passes through the urea channel of the nozzle core 4, and reaches the nozzle hole 5. The sprayed urea solution will form a urea spray on the front side of the nozzle body 2. The urea spray will be hydrolyzed to generate ammonia gas. The ammonia gas can reduce nitrogen oxides to nitrogen and water under the action of the catalyst.

When the urea nozzle works, the urea solution enters from the urea inlet 7, reaches the nozzle hole 5 through the urea channel of the nozzle core 4, and is ejected from the nozzle hole 5. At the same time, the gas enters from the gas inlet 3, and the gas entering from the gas inlet 3 , a part of the gas enters the nozzle hole 5 through the first gas channel 8 and the second gas channel 9, and is sprayed out together with the urea solution to participate in the atomization of the urea solution, which can obtain a better atomization effect, so that the diameter of the droplets Smaller; another part of the gas enters the air hole 6 through the first gas channel 8, and is directly sprayed out from the air hole 6, forming a gas barrier on the front side of the nozzle body 2, which can prevent the urea spray from forming crystals on the nozzle body 2 and protect the nozzle body 2.

The urea inlet 7 is located at the rear end of the urea nozzle, which can be located on the nozzle cover 1 or on the nozzle core 4 . The first gas channel 8 is located on the side where the nozzle core 4 is matched with the nozzle body 2 , and may be located on the nozzle core 4 or the nozzle body 2 .

Specifically, the nozzle hole 5 is located in the middle of the front end face of the shower head body 2 , and a plurality of air holes 6 are evenly distributed around the front end face of the shower head body 2 , as shown in FIG. 2 .

The urea solution is ejected from the nozzle hole 5 in the middle part of the front end of the nozzle body 2, and the formed urea spray will be centered on the nozzle hole 5 and will gradually diffuse; The front side of the nozzle body 2 forms a gas barrier to protect the nozzle body 2 to prevent the urea spray from staying on the front side of the nozzle body 2 and not form crystals on the nozzle body 2 .

Specifically, the matching surface between the front end of the nozzle core 4 and the inside of the front end of the nozzle body 2 can be a conical surface, an arc surface or a plane, and the preferred structure of the matching surface is a conical surface. Sealing, compared with the arc surface, the tapered surface is easier to process. The front end of the nozzle core 4 and the inside of the front end surface of the nozzle body 2 have a tapered surface with the same taper, and the tapered surface tapers in the direction of the nozzle hole 5 .

In a further specific embodiment, there is a first annular air chamber on the outside of the diverging end of the conical surface, and a plurality of air holes 6 are distributed on the first annular air chamber; a plurality of second gas passages 9 are distributed on the conical surface, communicating with the first annular air chamber. Annular air chamber and spray hole 5.

After the gas enters from the gas inlet 3, it enters the first annular air chamber, and is shunted from the first annular air chamber. Part of it is directly sprayed out from the air hole 6, and the other part enters the nozzle hole 5 through the second gas channel 9. From the nozzle hole 5 and the urea The solution is ejected simultaneously.

The air holes 6 are distributed on the first annular air chamber, and the first annular air chamber can make the pressure of the gas ejected from each air hole 6 be the same, and the pressure of the formed gas barrier is relatively uniform. The second gas channel 9 is distributed on the conical surface where the front end of the shower head core 4 matches the shower head body 2 , and the second gas channel 9 can be located on the shower head core 4 or on the shower head body 2 .

A plurality of second gas passages 9 are evenly distributed on the above-mentioned conical surface, so that the gas can be uniformly mixed with the urea solution from around the nozzle hole 5 to obtain a better atomization effect.

In another specific embodiment, the rear part of the side where the nozzle core 4 cooperates with the nozzle body 2 has a second annular air chamber, the gas inlet 3 is located on the side of the second annular air chamber, and the first gas channel 8 communicates with the first annular air chamber. Air chamber and the second annular air chamber.

The gas first enters the second annular gas chamber from the gas inlet 3, and then enters the first annular gas chamber through the first gas passage 8, and is divided in the first annular gas chamber. Through the two annular air chambers, the pressure of the gas ejected from each air hole 6 can be made the same, and the pressure of the gas flowing from each second gas passage 9 to the nozzle hole 5 can also be made the same, so that the atomization effect is more uniform.

Specifically, a plurality of first gas passages 8 are distributed on the side of the shower core 4 . The first gas passages 8 are evenly distributed on the side of the nozzle core 4. After the gas enters the second annular air chamber, it can enter the first annular air chamber evenly through the first gas passages 8, so that the pressure in the first annular air chamber is uniform. distribution, so as to obtain a more uniform atomization effect.

In a specific embodiment, as shown in Figure 3 and Figure 4, the number of the first gas passage 8 and the number of the second gas passage 9 are four, which are evenly distributed on the nozzle core 4, and each second gas passage 9 Corresponding to each first gas channel 8 respectively.

In the above embodiments, the nozzle cover 1 has a through hole, the rear end of the nozzle core 4 passes through the through hole, and the urea inlet 7 is located at the rear end of the nozzle core 4 . The urea inlet 7 can also be located on the nozzle cover 1 , and the urea inlet 7 and the spray hole 5 are connected through the urea channel of the nozzle core 4 .

In addition to the above-mentioned urea nozzle, the present invention also provides an SCR system, including a urea tank, a urea pump and a urea nozzle, the urea pump pumps the urea solution in the urea tank to the urea nozzle, and the urea nozzle is the above-mentioned each embodiment The urea nozzle described above.

The urea spray head has the above-mentioned technical effect, so the SCR system with the urea spray head also has the corresponding technical effect. For other structures of the SCR system, please refer to the prior art, which will not be repeated here.

The SCR system and the urea spray nozzle provided by the present invention have been introduced in detail above. In this paper, specific examples are used to illustrate the principle and implementation of the present invention, and the descriptions of the above embodiments are only used to help understand the method and core idea of the present invention. It should be pointed out that for those skilled in the art, without departing from the principle of the present invention, some improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims (9)

1. the urea nozzle of a SCR system, it is characterized in that, comprise sprayer body (2), sprinkler core (4) and nozzle cap (1), the front end of described sprayer body (2) has spray orifice (5) and pore (6), described nozzle cap (1) coordinates with the rear end of described sprayer body (2), described sprinkler core (4) is fixed in described sprayer body (2), the urea channel connection urea inlet (7) of described sprinkler core (4) and described spray orifice (5); The side of described sprayer body (2) has gas access (3), the side that described sprinkler core (4) coordinates with described sprayer body (2) has the first gas channel (8), and described first gas channel (8) is communicated with described gas access (3) and described pore (6); The fitting surface of the front end of described sprinkler core (4) and the front-end face inside of described sprayer body (2) has the second gas channel (9), and described second gas channel (9) is communicated with described first gas channel (8) and described spray orifice (5).

2. the urea nozzle of SCR system as claimed in claim 1, it is characterized in that, described spray orifice (5) is positioned at the middle part of the front-end face of described sprayer body (2), and multiple described pores (6) are distributed on the perimembranous of the front-end face of described sprayer body (2).

3. the urea nozzle of SCR system as claimed in claim 2, it is characterized in that, the fitting surface of the front end of described sprinkler core (4) and the front-end face inside of described sprayer body (2) is the conical surface.

4. the urea nozzle of SCR system as claimed in claim 3, it is characterized in that, the outside of the flaring end of the described conical surface has the first ring-shaped air chamber, and multiple described pore (6) is distributed on described first ring-shaped air chamber; Multiple described second gas channel (9) is distributed on the described conical surface, is communicated with described first ring-shaped air chamber and described spray orifice (5).

5. the urea nozzle of SCR system as claimed in claim 4, it is characterized in that, described sprinkler core (4) has the second ring-shaped air chamber with the rear portion of the side that described sprayer body (2) coordinates, described gas access (3) is positioned at the side of described second ring-shaped air chamber, and described first gas channel (8) is communicated with described first ring-shaped air chamber and described second ring-shaped air chamber.

6. the urea nozzle of SCR system as claimed in claim 5, it is characterized in that, multiple described first gas channels (8) are distributed in the side of described sprinkler core (4).

7. the urea nozzle of SCR system as claimed in claim 6, is characterized in that, described first gas channel (8) is four with the quantity of described second gas channel (9).

8. the urea nozzle of the SCR system as described in any one of claim 1 to 7, it is characterized in that, described nozzle cap (1) has through hole, the rear end of described sprinkler core (4) is through described through hole, and described urea inlet (7) is positioned at the rear end of described sprinkler core (4).

9. a SCR system, comprises urea box, urea pump and urea nozzle, and the urea solution pump in described urea box is given described urea nozzle by described urea pump, it is characterized in that, described urea nozzle is the urea nozzle described in above-mentioned 1 to 8 any one.