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CN208966393U - A kind of mixer and SCR system for SCR system - Google Patents

A kind of mixer and SCR system for SCR system Download PDF

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Publication number
CN208966393U
CN208966393U CN201821761795.8U CN201821761795U CN208966393U CN 208966393 U CN208966393 U CN 208966393U CN 201821761795 U CN201821761795 U CN 201821761795U CN 208966393 U CN208966393 U CN 208966393U
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China
Prior art keywords
flow guiding
guiding portion
conical flow
deflector
scr system
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CN201821761795.8U
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Chinese (zh)
Inventor
李磊
桂勇
田新娜
刘辰朋
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China Shipbuilding Power Engineering Institute Co Ltd
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China Shipbuilding Power Engineering Institute Co Ltd
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Abstract

The utility model belongs to diesel engine vent gas post-processing technology field, discloses a kind of mixer and SCR system for SCR system, including mixing tube, nozzle and guiding device.Nozzle and guiding device are set in mixing tube, guiding device includes conical flow guiding portion and the deflector of both ends open and hollow setting, conical flow guiding portion outer wall is formed with first passage with mixing between inside pipe wall, along tail gas circulating direction, the diameter in conical flow guiding portion is gradually increased, deflector is set in conical flow guiding portion and is formed between conical flow guiding portion inner wall second channel, and deflector and tail gas circulating direction are in angle.Conical flow guiding portion is by divided fluid stream at fluid inside and lateral fluid, lateral fluid circulates along first passage, conical flow guiding portion outer wall makes lateral fluid axially and radially be uniformly distributed and mix in mixing tube, fluid inside circulates along second channel, vortex is formed on rear side of deflector, fluid near vortex is further mixed under swirling action, to be sufficiently mixed to mixing cavity fluid.

Description

A kind of mixer and SCR system for SCR system
Technical field
The utility model relates to diesel engine vent gas post-processing technology field more particularly to a kind of mixing for SCR system Device and SCR system.
Background technique
Installation tail-gas after treatment apparatus is needed in the exhaust system of diesel engine, to reduce the nitrogen oxides in diesel engine vent gas (NOx) and the emission level of particulate matter.Selective catalytic reduction (Selective Catalytic Reduction, SCR) system System is one of the most effective measure of NOx emission reduced in diesel engine vent gas.
SCR technology is that the NOx in tail gas is reduced into nitrogen (N under the action of reducing agent2) and water.Existing SCR skill Art, which is mostly used, decomposes the ammonia (NH generated with urea3) it is used as reducing agent.
SCR system includes mixer and reactor etc..Mixer is connected to the exhaust pipe of diesel engine and reactor respectively, and Urea nozzle is provided in mixer.Certain hydrolysis and pyrolytic reaction occur in a mixer and generates for the urea sprayed from nozzle Ammonia, while after being mixed in mixer with the tail gas containing NOx, it flows into and carries out reduction reaction in reactor.
The experimental results show the uniformity coefficient of the resolution ratio of urea and ammonia distribution at SCR system reactor inlet The transfer efficiency of nitrogen oxides in reactor is had a major impact, the overall performance of entire used urea SCR system is directly affected.But it is existing Have in the mixer of SCR system, the atomization and vaporization and hydrolysis pyrolytic reaction of urea are insufficient, and the mixing of urea and tail gas is uneven It is even, cause the transfer efficiency of nitrogen oxides and urea desorption column in SCR reactor lower, the escaping of ammonia rate is high.In addition, existing In the mixer of SCR system, in order to make mixer reach preferable mixed effect, more complicated mixer knot is usually set Structure, and this often leads to exhaust resistance raising, diesel engine power consumption increases.
Utility model content
The purpose of this utility model is to provide a kind of mixers and SCR system for SCR system, to promote urea to steam Hydrolyzing and urea and tail gas in a mixer uniform mix.
To achieve the above object, the following technical schemes are provided:
A kind of mixer for SCR system, including mixing tube, nozzle and guiding device, the nozzle and the water conservancy diversion Device is set in the mixing tube, and the guiding device includes conical flow guiding portion and the water conservancy diversion of both ends open and hollow setting Plate, conical flow guiding portion outer wall are formed with first passage with described mix between inside pipe wall, along tail gas circulating direction, the cone The diameter of shape diversion division is gradually increased, the deflector be set to the conical flow guiding portion in and with conical flow guiding portion inner wall it Between be formed with second channel, the deflector and tail gas circulating direction are in angle.
Further, osculum end of the deflector close to the conical flow guiding portion.
Further, the deflector is perpendicular to the tail gas circulating direction.
Further, the deflector is cylindric.
Further, the injection direction of the nozzle is identical as the tail gas circulating direction.
Further, along the tail gas circulating direction, the nozzle is set to the upstream in the conical flow guiding portion.
Further, along the tail gas circulating direction, the nozzle is set to the downstream in the conical flow guiding portion, and close to institute State the big opening end in conical flow guiding portion.
Further, the nozzle is set in the conical flow guiding portion, and is located at the deflector and is led close to the taper The side of the big opening end in stream portion.
It further, further include intermediate tube, along the tail gas circulating direction, the intermediate tube is connected to the mixing tube Downstream.
A kind of SCR system, the mixer including being used for SCR system as described above.
Compared with prior art, in the mixer and SCR system provided by the utility model for SCR system, taper is led Stream portion is by divided fluid stream at fluid inside and lateral fluid, and lateral fluid circulates along first passage, and lateral fluid is in conical flow guiding To while the axial flowing of mixing tube under the guide functions of the outer wall in portion, is also flowed to the radial direction of mixing tube, promote stream Body is uniformly distributed and mixes in mixing tube;Fluid inside is flowed into conical flow guiding portion by the osculum end in conical flow guiding portion Portion can only be passed through, after deflector by the blocking of deflector from the gap, that is, second channel in deflector and conical flow guiding portion There are a lesser areas of slack water of flow velocity for side, form vortex, the fluid near vortex is further mixed, final to realize to mixing Intracavitary fluid is sufficiently mixed.
Detailed description of the invention
Fig. 1 is the cross-sectional view of the mixer provided by the embodiment of the utility model for SCR system;
Fig. 2 be Fig. 1 in A to side view;
Fig. 3 is the connection schematic diagram in conical flow guiding portion and outer floor provided by the embodiment of the utility model;
Fig. 4 be Fig. 1 in B to side view.
Appended drawing reference:
1- mixing tube;2- nozzle;3- conical flow guiding portion;31- osculum end;32- big opening end;4- deflector;The outer floor of 5-;6- Inner rib plate;7- intermediate tube;8- connecting flange.
Specific embodiment
The technical issues of to solve the utility model, the technical solution of use and the technical effect that reaches are clearer, It is described in further detail below in conjunction with technical solution of the attached drawing to the utility model embodiment, it is clear that described reality Applying example is only the utility model a part of the embodiment, instead of all the embodiments.Based on the embodiments of the present invention, It is practical new to belong to this for those skilled in the art's every other embodiment obtained without making creative work The range of type protection.
As shown in Figure 1, its cross-sectional view for the present embodiment for the mixer of SCR system.This is used for the mixing of SCR system Device is generally mounted in the exhaust gas aftertreatment system of diesel engine, specifically include mixing tube 1, intermediate tube 7, nozzle 2, guiding device and Connecting flange 8.Nozzle 2 and guiding device are set in mixing tube 1.Guiding device includes conical flow guiding portion 3 and deflector 4.In Between the both ends of pipe 7 be connected with the reactor (not shown) of mixing tube 1 and SCR system respectively by connecting flange 8.Mixing tube 1 other end is connected by connecting flange 8 with the exhaust duct (not shown) of diesel engine.Flow into mixing tube 1 in tail gas and The urea sprayed from nozzle 2 is sufficiently mixed under the action of guiding device, is flowed through intermediate tube 7 later and is entered eventually into SCR system In the reactor of system.In view of the corrosivity of aqueous solution of urea, guiding device provided in this embodiment, i.e. 3 He of conical flow guiding portion Deflector 4 is all made of the stainless steel making of 304 stainless steels or higher level.
Fig. 2 be in Fig. 1 A to side view, along tail gas circulating direction it can be seen from Fig. 1 and Fig. 2, conical flow guiding portion 3 Diameter is gradually increased, and multiple outer floors 5 are welded between conical flow guiding portion 3 and mixing tube 1,3 outer wall and mixed in conical flow guiding portion It closes and is formed with first passage between 1 inner wall of pipe.It is also seen that the axis in conical flow guiding portion 3 is overlapped with the axis of mixing tube 1.Fig. 3 For the connection schematic diagram in the present embodiment conical flow guiding portion 3 and outer floor 5.It can be seen that in the present embodiment in conjunction with Fig. 2 and Fig. 3, outside Floor 5 is set as four, and four outer floors 5 are uniformly distributed along the central axis of mixing tube 1.In other embodiments, outer floor 5 Quantity can be set to one, two, three or more, as long as can be realized the company between conical flow guiding portion 3 and mixing tube 1 It connects.
Fig. 4 be Fig. 1 in B to side view, be located in conical flow guiding portion 3 by deflector 4 it can be seen from Fig. 1 and Fig. 4, led It is welded with multiple inner rib plates 6 between flowing plate 4 and conical flow guiding portion 3, is formed between 3 inner wall of deflector 4 and conical flow guiding portion Second channel.In the present embodiment, deflector 4 is cylindric, and the central axis of deflector 4 and conical flow guiding portion 3 and is mixed The axis of pipe 1 is overlapped.Inner rib plate 6 is also set as four, and four inner rib plates 6 are uniformly distributed with the central axis of mixing tube 1.Tail gas It can circulate in the space (i.e. first passage) between 1 inner wall of conical flow guiding portion 3 and mixing tube, it also can be by conical flow guiding portion 3 Osculum end 31 enters in conical flow guiding portion 3, flows through gap (i.e. second channel) circulation in deflector 4 and conical flow guiding portion 3, finally It is flowed out from the big opening end 32 in conical flow guiding portion 3.
Along tail gas circulating direction, the upstream of guiding device is arranged in nozzle 2.The injection center of nozzle 2 is located at mixing tube 1 On axis, the injection direction of nozzle 2 is identical as tail gas circulating direction, is each perpendicular to mixing tube 1, conical flow guiding portion 3 and water conservancy diversion The section of plate 4.In the present embodiment, the internal diameter of mixing tube 1 is 800mm, length 1000mm, the internal diameter of intermediate tube 7 be 800mm, Length is 2800mm, and 3 osculum end 31 of conical flow guiding portion is away from nozzle 2 apart from for 400mm, and 31 internal diameter of osculum end is 100mm, and taper is led The oblique angle in stream portion 3 is 30 degree, and conical flow guiding portion 3 is 400mm in the length of 1 axial direction of mixing tube, and deflector 4 is away from conical flow guiding The distance of 3 osculum end of portion, 31 axis direction is 100mm, and the diameter of deflector 4 is 180mm.Certainly, in other embodiments, respectively The specific size of component can according to the actual situation depending on.The guiding device structure type is simple, and arrangement is convenient, exhaust resistance compared with It is low, from nozzle 2 spray aqueous solution of urea after the atomization and vaporization of a distance, mixed with tail gas, the temperature of tail gas generally compared with Height, the urea after atomization and vaporization can also constantly hydrolyze pyrolysis and generate ammonia during mixing with the higher tail gas of temperature, be formed Gaseous mixture.When mixed airflow to conical flow guiding portion 3, inside gaseous mixture and outside gaseous mixture are split by conical flow guiding portion 3.
The outer wall in conical flow guiding portion 3 is simultaneously along the axially and radially extension of mixing tube 1, and outside gaseous mixture is along first passage stream When logical, outside gaseous mixture is under the guide functions of the outer wall in conical flow guiding portion 3, while along the axial direction circulation of mixing tube 1, Also it to the inner wall of mixing tube 1, i.e., circulates and spreads along the radial direction of mixing tube 1, so that point of the outside gaseous mixture in mixing tube 1 Cloth is more uniform, while extending outside gaseous mixture in the circulation of circulation distance, gaseous mixture in mixing tube 1 in mixing tube 1 The hydrolysis of time and urea is pyrolyzed reaction time, the final further mixing for promoting outside gaseous mixture.In addition, in conical flow guiding The circumferential direction in portion 3 is uniformly distributed and in four outer floor 5 of cross type setting, in addition to connection function, can also promote outer Side gaseous mixture being uniformly distributed and mixing in the space between conical flow guiding portion 3 and mixing tube 1.
In the present embodiment, conical flow guiding portion 3 is axially symmetric structure, and along tail gas circulating direction, the diameter in conical flow guiding portion 3 Linearly increasing, i.e., the bus in conical flow guiding portion 3 is straight line.In other embodiments, conical flow guiding portion 3 is necessarily axial symmetry knot Structure, and the diameter in conical flow guiding portion 3 need not also change linearly, the bus in conical flow guiding portion 3 can be broken line or curve, as long as energy It is enough so that conical flow guiding portion 3 is axially extending along mixing tube 1 while, also continuous radially extending to mixing tube 1, can finally promote It is uniformly distributed into outside gaseous mixture mixing tube 1 is circumferential and radial.The position in conical flow guiding portion 3 and size can be according to mixed The internal diameter for closing pipe 1 is adjusted scaling.
Inside gaseous mixture enters in conical flow guiding portion 3 from the osculum end 31 in conical flow guiding portion 3, encounters during circulation Deflector 4, blocking of the circulation of inside gaseous mixture by deflector 4, inside gaseous mixture can only be from deflectors 4 and conical flow guiding portion 3 gap, that is, second channel flows through.At this point, in the rear side of deflector 4, i.e., circulating direction along inside gaseous mixture, in deflector 4 Downstream and be located near deflector 4, can have the lesser area of slack water of flow velocity, to form low-pressure area, and conical flow guiding portion 3 The flow velocity of fluid is relatively fast near outside and close big opening end 32, quick flow region and inside in 3 outside of conical flow guiding portion Under the collective effect of low-pressure area, vortex is formed in the rear side of deflector 4.It inside gaseous mixture near vortex and flow to taper and leads Outside gaseous mixture near 3 big opening end 32 of stream portion can be further mixed under the action of vortex, extend urea and pyrolysis water occurs The reaction time of solution promotes urea to decompose, improves the degree that is evenly distributed of ammonia.It should be pointed out that the model of above-mentioned low-pressure area It encloses by the oblique angle in conical flow guiding portion 3, the length in conical flow guiding portion 3, the size of deflector 4 and deflector 4 relative to conical flow guiding The position in portion 3 codetermines.In addition, in other embodiments, deflector 4 necessarily mutually hangs down with the circulating direction of inside gaseous mixture Directly, as long as deflector 4 and inside gaseous mixture are in angle, area of slack water can be formed in the rear side of deflector 4.
In the present embodiment, deflector 4 is preferably to be arranged close to the osculum end 31 in conical flow guiding portion 3, after deflector 4 Side forms biggish vortex.It is also pointed out that the shape of deflector 4 be not limited to the present embodiment in it is thin cylindric, as long as energy Enough play the role of baffle, and forms area of slack water at the rear of deflector 4.The position of deflector 4 and size can also be according to mixed The size of the internal diameter and conical flow guiding portion 3 that close pipe 1 is adjusted scaling.
Further, along tail gas circulating direction, nozzle 2 can also be provided at the downstream of guiding device, and nozzle 2 is preferably at this time Big opening end 32 close to conical flow guiding portion 3 is arranged.Tail gas splits into inside tail gas and outside tail gas, inside by conical flow guiding portion 3 Tail gas, the outside tail gas flowing near 3 big opening end 32 of conical flow guiding portion and the urea after spraying simultaneously atomization and vaporization in nozzle 2 It is more adequately mixed under the action of 4 rear side vortex of deflector.To further increase mixed effect, nozzle 2 can also be set to cone The inside of shape diversion division 3, and nozzle 2 is located at deflector 4 close to the side of 3 big opening end 32 of conical flow guiding portion.It should be noted that The position at the injection center of nozzle 2 is not limited to the axis of mixing tube 1, the injection direction of nozzle 2 also necessarily with tail gas circulation side To identical.
It through the well-mixed gaseous mixture of guiding device, flows into intermediate tube 7 and is further mixed, intermediate tube 7 is used In guarantee that intermediate tube 7 exports the uniformity and urea resolution ratio of ammonia at end section, the length of intermediate tube 7 is preferably not less than Between 3.5 times of 7 diameter of pipe.
The present embodiment also provides a kind of SCR system, and the mixer including being used for SCR system as described above can make to urinate Element is uniformly mixed with tail gas, is accelerated the evaporation of aqueous solution of urea, is promoted the pyrolysis hydrolytic process of urea, in SCR reactor inlet Place, which forms uniform ammonia distribution, reduces the escaping of ammonia rate, and can drop to improve the transfer efficiency and urea desorption column of nitrogen oxides Low exhaust resistance, and then reduce diesel engine energy consumption.
Note that above are only the preferred embodiment and institute's application technology principle of the utility model.Those skilled in the art's meeting Understand, the utility model is not limited to specific embodiment described here, is able to carry out for a person skilled in the art various bright Aobvious variation, readjustment and substitution is without departing from the protection scope of the utility model.Therefore, although passing through above embodiments The utility model is described in further detail, but the utility model is not limited only to above embodiments, is not departing from It can also include more other equivalent embodiments in the case that the utility model is conceived, and the scope of the utility model is by appended Scope of the claims determine.

Claims (10)

1. a kind of mixer for SCR system, which is characterized in that described including mixing tube (1), nozzle (2) and guiding device Nozzle (2) and the guiding device are set in the mixing tube (1), and the guiding device includes both ends open and hollow setting Conical flow guiding portion (3) and deflector (4), be formed between conical flow guiding portion (3) outer wall and the mixing tube (1) inner wall First passage, along tail gas circulating direction, the diameter of the conical flow guiding portion (3) is gradually increased, and the deflector (4) is set to described Second channel, the deflector (4) and tail are formed in conical flow guiding portion (3) and between conical flow guiding portion (3) inner wall Gas circulating direction is in angle.
2. the mixer according to claim 1 for SCR system, which is characterized in that the deflector (4) is close to described The osculum end (31) in conical flow guiding portion (3).
3. the mixer according to claim 2 for SCR system, which is characterized in that the deflector (4) is perpendicular to institute State tail gas circulating direction.
4. the mixer according to claim 3 for SCR system, which is characterized in that the deflector (4) is cylinder Shape.
5. the mixer according to claim 4 for SCR system, which is characterized in that the injection direction of the nozzle (2) It is identical as the tail gas circulating direction.
6. the mixer according to claim 5 for SCR system, which is characterized in that along the tail gas circulating direction, institute State the upstream that nozzle (2) are set to the conical flow guiding portion (3).
7. the mixer according to claim 5 for SCR system, which is characterized in that along the tail gas circulating direction, institute The downstream that nozzle (2) are set to the conical flow guiding portion (3) is stated, and close to the big opening end (32) of the conical flow guiding portion (3).
8. the mixer according to claim 5 for SCR system, which is characterized in that the nozzle (2) is set to the cone In shape diversion division (3), and it is located at the deflector (4) close to the side of the big opening end (32) of the conical flow guiding portion (3).
9. the mixer according to claim 1-8 for SCR system, which is characterized in that further include intermediate tube (7), along the tail gas circulating direction, the intermediate tube (7) is connected to the downstream of the mixing tube (1).
10. a kind of SCR system, which is characterized in that including the described in any item mixing for SCR system of such as claim 1-9 Device.
CN201821761795.8U 2018-10-29 2018-10-29 A kind of mixer and SCR system for SCR system Active CN208966393U (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201821761795.8U CN208966393U (en) 2018-10-29 2018-10-29 A kind of mixer and SCR system for SCR system

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Application Number Priority Date Filing Date Title
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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108590826A (en) * 2018-06-12 2018-09-28 哈尔滨工程大学 Hydrojet quick steaming unit in pipeline
CN109252925A (en) * 2018-10-29 2019-01-22 中船动力研究院有限公司 A kind of mixer and SCR system for SCR system
CN111112195A (en) * 2020-01-13 2020-05-08 韶关市铁友建设机械有限公司 Guiding jet plate for cleaning slurry balance cutter head

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108590826A (en) * 2018-06-12 2018-09-28 哈尔滨工程大学 Hydrojet quick steaming unit in pipeline
CN109252925A (en) * 2018-10-29 2019-01-22 中船动力研究院有限公司 A kind of mixer and SCR system for SCR system
CN109252925B (en) * 2018-10-29 2024-07-09 中船动力研究院有限公司 Mixer for SCR system and SCR system
CN111112195A (en) * 2020-01-13 2020-05-08 韶关市铁友建设机械有限公司 Guiding jet plate for cleaning slurry balance cutter head

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