CN110848007B - Urea mixing device - Google Patents
Urea mixing device Download PDFInfo
- Publication number
- CN110848007B CN110848007B CN201911315003.3A CN201911315003A CN110848007B CN 110848007 B CN110848007 B CN 110848007B CN 201911315003 A CN201911315003 A CN 201911315003A CN 110848007 B CN110848007 B CN 110848007B
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- plate
- urea
- crushing
- cavity
- partition plate
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- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Chemical compound NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 title claims abstract description 137
- 239000004202 carbamide Substances 0.000 title claims abstract description 137
- 238000002156 mixing Methods 0.000 title claims abstract description 59
- 238000005192 partition Methods 0.000 claims abstract description 55
- 239000011148 porous material Substances 0.000 claims abstract description 16
- 238000002347 injection Methods 0.000 claims abstract description 14
- 239000007924 injection Substances 0.000 claims abstract description 14
- 239000007921 spray Substances 0.000 claims description 14
- 239000007788 liquid Substances 0.000 abstract description 67
- 230000000694 effects Effects 0.000 abstract description 14
- 239000007789 gas Substances 0.000 description 48
- 239000013078 crystal Substances 0.000 description 19
- 238000006243 chemical reaction Methods 0.000 description 12
- 210000001624 hip Anatomy 0.000 description 9
- 238000005507 spraying Methods 0.000 description 8
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 7
- 238000007664 blowing Methods 0.000 description 7
- 238000002425 crystallisation Methods 0.000 description 6
- 230000008025 crystallization Effects 0.000 description 6
- 238000009826 distribution Methods 0.000 description 5
- 238000000354 decomposition reaction Methods 0.000 description 4
- 229910021529 ammonia Inorganic materials 0.000 description 3
- 230000002349 favourable effect Effects 0.000 description 3
- MWUXSHHQAYIFBG-UHFFFAOYSA-N nitrogen oxide Inorganic materials O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 description 3
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 229910002091 carbon monoxide Inorganic materials 0.000 description 2
- 239000003054 catalyst Substances 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 230000002035 prolonged effect Effects 0.000 description 2
- 235000017060 Arachis glabrata Nutrition 0.000 description 1
- 241001553178 Arachis glabrata Species 0.000 description 1
- 235000010777 Arachis hypogaea Nutrition 0.000 description 1
- 235000018262 Arachis monticola Nutrition 0.000 description 1
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 1
- 239000004215 Carbon black (E152) Substances 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 230000032683 aging Effects 0.000 description 1
- 238000003915 air pollution Methods 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 238000000889 atomisation Methods 0.000 description 1
- 230000000903 blocking effect Effects 0.000 description 1
- 238000010531 catalytic reduction reaction Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
- 150000002430 hydrocarbons Chemical class 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 235000020232 peanut Nutrition 0.000 description 1
- 238000006722 reduction reaction Methods 0.000 description 1
- 238000009827 uniform distribution Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
- F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
- F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
- F01N3/24—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by constructional aspects of converting apparatus
- F01N3/28—Construction of catalytic reactors
- F01N3/2892—Exhaust flow directors or the like, e.g. upstream of catalytic device
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
- F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
- F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
- F01N3/18—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control
- F01N3/20—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control specially adapted for catalytic conversion ; Methods of operation or control of catalytic converters
- F01N3/2006—Periodically heating or cooling catalytic reactors, e.g. at cold starting or overheating
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
- F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
- F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
- F01N3/18—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control
- F01N3/20—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control specially adapted for catalytic conversion ; Methods of operation or control of catalytic converters
- F01N3/2066—Selective catalytic reduction [SCR]
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N5/00—Exhaust or silencing apparatus combined or associated with devices profiting by exhaust energy
- F01N5/02—Exhaust or silencing apparatus combined or associated with devices profiting by exhaust energy the devices using heat
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N2610/00—Adding substances to exhaust gases
- F01N2610/02—Adding substances to exhaust gases the substance being ammonia or urea
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N2610/00—Adding substances to exhaust gases
- F01N2610/14—Arrangements for the supply of substances, e.g. conduits
- F01N2610/1453—Sprayers or atomisers; Arrangement thereof in the exhaust apparatus
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/10—Internal combustion engine [ICE] based vehicles
- Y02T10/12—Improving ICE efficiencies
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Health & Medical Sciences (AREA)
- Toxicology (AREA)
- Exhaust Gas After Treatment (AREA)
Abstract
The invention discloses a urea mixing device, wherein a partition plate is arranged between a front shell and a rear shell, a crushing plate is fixed on the partition plate, a front baffle plate is arranged at the front end part of the partition plate, an opening is formed on the front baffle plate corresponding to the partition plate, a guide plate and a pore plate are arranged on the opening, and an air inlet is formed between the guide plate and the inner wall surface corresponding to the front shell; the guide plate is provided with blades which are opened inwards towards the injection cavity; the pore plate is provided with a plurality of first through holes; a grid opening is formed in the wall surface, opposite to the crushing plate, of the partition plate; the rear housing is formed with a waisted portion. The baffle plate and the crushing plate are provided with the grid openings in a right-to-right manner, the grid openings have a secondary crushing effect on urea liquid drops, the urea liquid drops are guaranteed to be atomized and volatilized more thoroughly, the full mixing of mixed air flows is facilitated, and the mixing uniformity is higher. The back shell is formed with and receives the waist, and the velocity of flow can increase when receiving the waist in the mixed air current, and the mixing effect is better, and the misce bene is higher.
Description
Technical Field
The invention relates to the technical field of automobile exhaust aftertreatment, in particular to a urea mixing device.
Background
The automobile exhaust aftertreatment device belongs to an engine exhaust system, and is mainly used for converting harmful gases such as nitrogen oxides (NO X), hydrocarbon (CH), carbon monoxide (CO) and the like in automobile exhaust into nitrogen (N 2), water (H 2 O) and the like which are harmless to the environment. At present, the DOC (oxidation catalyst) +DPF (particulate filter) +SCR (selective catalytic reduction) technology is often adopted in the diesel engine state to carry out aftertreatment on the exhaust emission, but the atomization and mixing effect of the urea aqueous solution in the aftertreatment has great influence on the selective reduction reaction carried out in the subsequent SCR, and the improvement of the uniformity of the mixing of urea and the exhaust in a mixer is the key for improving the conversion efficiency of the aftertreatment.
The existing tail gas aftertreatment mixer generally has the problems of poor uniformity of gas flow velocity distribution and poor uniformity of ammonia mixing. Poor uniformity of gas flow velocity distribution can lead to uneven catalyst aging on the one hand; on the other hand, because the gas flow velocity distribution is uneven, the temperature of the inner wall surface in the area with smaller gas flow velocity is lower in the tail gas aftertreatment mixing device, and when urea liquid drops contact the inner wall surface of the part, a part of heat can be taken away, so that the temperature of the inner wall surface of the part is further reduced, urea liquid drops falling on the inner wall surface with excessively low temperature are volatilized due to insufficient heat absorption, urea crystals are easily formed, and the conversion efficiency of aftertreatment can be greatly reduced. Once urea crystals appear, unless the engine enters a high temperature working condition, the crystals burn off, the crystals can grow gradually over time, eventually plug the mixer, and even plug the surface of the SCR carrier, resulting in aftertreatment failure. If the urea injection amount is large and the ammonia is not fully and uniformly mixed, insufficient reaction can occur in the SCR system, so that the exhaust emission is affected, a large amount of ammonia can be overflowed, and air pollution is caused.
Disclosure of Invention
The application provides a peanut shell type urea mixing device with reasonable structure, which aims at the defects of poor gas flow velocity distribution uniformity, easiness in forming urea crystals, poor mixing uniformity and the like of the existing tail gas aftertreatment mixer, and has the advantages of high gas flow velocity distribution uniformity, low crystallization risk and high mixing uniformity.
The technical scheme adopted by the invention is as follows:
An inner cavity is formed between a front shell and a rear shell, an air inlet cylinder is arranged at the upper part of the front shell, an air outlet is arranged at the lower part of the front shell, a partition plate is arranged between the front shell and the rear shell, a crushing plate is fixed on the partition plate, and the partition plate and the crushing plate divide the inner cavity into an injection cavity positioned inside the partition plate and outside the crushing plate, a mixing cavity positioned between the crushing plate and the partition plate and a diversion cavity positioned outside the partition plate; the front end part of the baffle plate is provided with a front baffle plate, the front baffle plate is provided with an opening corresponding to the baffle plate, the opening is provided with a guide plate and a pore plate, and an air inlet is formed between the outer side edge of the guide plate and the inner wall surface corresponding to the front shell; the guide plate is provided with a first opening and a second opening, and the second opening is provided with blades which are opened inwards towards the injection cavity; the pore plate is provided with a plurality of first through holes; a grid opening is formed in the wall surface, opposite to the crushing plate, of the partition plate; the longitudinal middle part of the rear shell is inwards recessed towards the inner cavity to form a waisted part.
The tail gas flow in the internal cavity is decomposed and mixed for a plurality of times, urea dropping liquid is fully decomposed, and decomposed NH 3 is fully mixed with the tail gas, so that the mixing uniformity is high, and the NO X conversion rate is high. A plurality of grid openings are formed in the partition plate and the crushing plate in a right-to-right manner, and the grid openings are positioned on one side opposite to the nozzle seat, so that on one hand, the grid openings have a secondary crushing effect on urea liquid drops, the urea liquid drops are further crushed into smaller size, and the urea liquid drops are atomized and volatilized more thoroughly; on the other hand, the mixed air flow in the mixing cavity flows into the flow guiding cavity through the grid openings, so that the flow velocity of the mixed air flow is not too fast, the mixed air flow is more favorable for being fully mixed, and the mixing uniformity is higher. The left side and the right side of the longitudinal middle part of the rear shell are provided with waists, and the cross section size of the waists is smaller than that of the upper part and the lower part of the rear shell; when the mixed air flowing along the wall surface of the rear shell passes through the waist, the flow speed of the mixed air can be increased due to the fact that the section size is reduced, the accelerated mixed air enters the inner wall surface with the enlarged section size along the inner wall surface of the waist, then swirl is formed more easily, the swirl effect is better, the mixing effect of the mixed air is better, and the mixing uniformity is higher.
As a further improvement of the above technical scheme:
A pit is formed on the outer surface of the upper part of the rear shell in an inward concave manner, a nozzle seat is arranged on the bottom surface of the pit, and a urea nozzle is arranged on the nozzle seat; a shielding plate is fixedly arranged on the inner wall surface of the rear shell corresponding to the pit, and the shielding plate shields the periphery of one side of the nozzle seat, which is positioned on the air inlet cylinder.
A U-shaped shielding plate with one end open and one end closed is fixedly arranged on the inner wall surface of the rear shell corresponding to the pit, the closed end of the U-shaped shielding plate is positioned on one side of the air inlet cylinder, the shielding plate shields the periphery of a urea nozzle on the nozzle seat, namely the shielding plate is arranged on the periphery of the nozzle seat on one side of the air inlet cylinder, so that the exhaust gas flow entering the air inlet cylinder is blocked, the exhaust gas flow is prevented from directly blowing urea injection rays, and urea liquid drops are blown onto the inner wall surface of the rear shell to form urea crystals.
The shielding plate is positioned on the inner side of the air inlet.
The shielding plate is correspondingly positioned at the inner side of the air inlet, and the tail gas flow entering from the air inlet can heat the shielding plate, so that urea liquid drops falling on the shielding plate fully absorb heat and volatilize, and urea crystals are prevented from being formed.
The shielding plate is U-shaped with one end open and one end closed.
The partition board is U-shaped and comprises a circular arc section and a parallel section; the front baffle is correspondingly provided with a U-shaped opening.
The guide plate is a square plate and is correspondingly arranged on the front side of the parallel section of the partition plate; blade openings on the deflector are opposite to the crushing plate.
According to the invention, the blade openings of the guide plate are opposite to the crushing plate, so that the mixed air flow can be guided to blow to the crushing plate, on one hand, the mixed air flow can be prevented from directly blowing urea injection rays to blow urea drops to the inner wall surface of the rear shell to form urea crystals, and the risk of urea crystallization on the rear shell is reduced; on the other hand, the blades guide the mixed air flow to blow to the crushing plate, so that the heat of the tail gas can be fully utilized, urea drops falling on the crushing plate fully absorb heat and volatilize, the volatilization rate of the urea drops is improved, and the conversion efficiency of NO X is further improved; in addition, the blade has a scattering and crushing effect on urea liquid drops, and the urea liquid drops are crushed into smaller liquid drops and are easier to volatilize.
The orifice plate is a semicircular arc plate and is correspondingly arranged at the front side of the circular arc section of the partition plate.
The pore plate is a semicircular arc plate, the pore plate is correspondingly arranged on the front side of the circular arc section of the partition plate, the tail gas flow is dispersed into the mixing cavity through the pore plate, the air inlet is more uniform, the tail gas flow is more fully mixed with urea drops which are crushed and volatilized by the crushing plate, the urea drops further absorb heat and volatilize, the volatilization rate of the urea drops is improved, and the conversion efficiency of NO X is further improved.
The crushing plate is an arc-shaped plate, and the arc shape of the crushing plate protrudes towards the direction of the arc section of the partition plate.
The crushing plate is an arc-shaped plate, and plays a role in scattering and crushing urea liquid drops, and the urea liquid drops are crushed into smaller liquid drops which are easier to volatilize; the circular arc shape of the spray chamber protrudes towards the direction of the circular arc section of the partition plate, namely the crushing plate protrudes towards the direction away from the nozzle seat, so that the spray space of the spray chamber can be increased, urea liquid drops and tail gas flow have sufficient space for mixing, and the mixing property is better; the crushing plate is protruded in the direction away from the nozzle seat, so that the area of the crushing wall surface of urea liquid drops can be increased, and the urea liquid drops are fully crushed into smaller liquid drops.
Grooves are respectively formed in the two outer sides of the crushing plate, corresponding to the partition plates.
Grooves are respectively formed in the two outer sides of the corresponding partition boards, mixed air flows can flow downwards along the inner wall surfaces of the arc sections of the partition boards after flowing through the grooves, the inner wall surfaces of the arc sections of the partition boards are heated, urea drops falling on the inner wall surfaces of the arc sections 27 are enabled to absorb heat fully and volatilize, and urea crystallization is avoided.
A plurality of grid openings which are arranged in an array manner are arranged on the wall surface of the circular arc section of the partition plate, which corresponds to one side of the flow guide cavity.
The grille opening is arranged on the wall surface positioned at one side of the flow guiding cavity, so that the mixed air flow can be guided to downwards enter the flow guiding cavity, and urea crystals are prevented from being formed by urea liquid drops in the mixed air flow deposited on the side wall surface due to the fact that the mixed air flow flowing through the grille opening impinges on the side wall surface of the rear shell.
The beneficial effects of the invention are as follows:
The tail gas flow in the internal cavity is decomposed and mixed for a plurality of times, urea dropping liquid is fully decomposed, and decomposed NH 3 is fully mixed with the tail gas, so that the mixing uniformity is high, and the NO X conversion rate is high. A plurality of grid openings are formed in the partition plate and the crushing plate in a right-to-right manner, and the grid openings are positioned on one side opposite to the nozzle seat, so that on one hand, the grid openings have a secondary crushing effect on urea liquid drops, the urea liquid drops are further crushed into smaller size, and the urea liquid drops are atomized and volatilized more thoroughly; on the other hand, the mixed air flow in the mixing cavity flows into the flow guiding cavity through the grid openings, so that the flow velocity of the mixed air flow is not too fast, the mixed air flow is more favorable for being fully mixed, and the mixing uniformity is higher. The left side and the right side of the longitudinal middle part of the rear shell are provided with waists, and the cross section size of the waists is smaller than that of the upper part and the lower part of the rear shell; when the mixed air flowing along the wall surface of the rear shell passes through the waist, the flow speed of the mixed air can be increased due to the fact that the section size is reduced, the accelerated mixed air enters the inner wall surface with the enlarged section size along the inner wall surface of the waist, then swirl is formed more easily, the swirl effect is better, the mixing effect of the mixed air is better, and the mixing uniformity is higher.
A U-shaped shielding plate with one end open and one end closed is fixedly arranged on the inner wall surface of the rear shell corresponding to the pit, the closed end of the U-shaped shielding plate is positioned on one side of the air inlet cylinder, the shielding plate shields the periphery of a urea nozzle on the nozzle seat, namely the shielding plate is arranged on the periphery of the nozzle seat on one side of the air inlet cylinder, so that the exhaust gas flow entering the air inlet cylinder is blocked, the exhaust gas flow is prevented from directly blowing urea injection rays, and urea liquid drops are blown onto the inner wall surface of the rear shell to form urea crystals. The shielding plate is correspondingly positioned at the inner side of the air inlet, and the tail gas flow entering from the air inlet can heat the shielding plate, so that urea liquid drops falling on the shielding plate fully absorb heat and volatilize, and urea crystals are prevented from being formed.
According to the invention, the blade openings of the guide plate are opposite to the crushing plate, so that the mixed air flow can be guided to blow to the crushing plate, on one hand, the mixed air flow can be prevented from directly blowing urea injection rays to blow urea drops to the inner wall surface of the rear shell to form urea crystals, and the risk of urea crystallization on the rear shell is reduced; on the other hand, the blades guide the mixed air flow to blow to the crushing plate, so that the heat of the tail gas can be fully utilized, urea drops falling on the crushing plate fully absorb heat and volatilize, the volatilization rate of the urea drops is improved, and the conversion efficiency of NO X is further improved; in addition, the blade has a scattering and crushing effect on urea liquid drops, and the urea liquid drops are crushed into smaller liquid drops and are easier to volatilize.
The pore plate is a semicircular arc plate, the pore plate is correspondingly arranged on the front side of the circular arc section of the partition plate, the tail gas flow is dispersed into the mixing cavity through the pore plate, the air inlet is more uniform, the tail gas flow is more fully mixed with urea drops which are crushed and volatilized by the crushing plate, the urea drops further absorb heat and volatilize, the volatilization rate of the urea drops is improved, and the conversion efficiency of NO X is further improved.
The crushing plate is an arc-shaped plate, and plays a role in scattering and crushing urea liquid drops, and the urea liquid drops are crushed into smaller liquid drops which are easier to volatilize; the circular arc shape of the spray chamber protrudes towards the direction of the circular arc section of the partition plate, namely the crushing plate protrudes towards the direction away from the nozzle seat, so that the spray space of the spray chamber can be increased, urea liquid drops and tail gas flow have sufficient space for mixing, and the mixing property is better; the bulge of the breaking plate 7 in the direction away from the nozzle seat can also increase the area of the breaking wall surface of the urea liquid drops, so that the urea liquid drops are sufficiently broken into smaller liquid drops. The crushing plate is provided with grooves at two outer sides of the corresponding partition plate respectively, mixed air flows downwards along the inner wall surface of the circular arc section of the partition plate after flowing through the grooves, and heats the inner wall surface of the circular arc section of the partition plate, so that urea liquid drops falling on the inner wall surface of the circular arc section 27 fully absorb heat and volatilize, and urea crystallization is avoided.
The grille opening is arranged on the wall surface positioned at one side of the flow guiding cavity, so that the mixed air flow can be guided to downwards enter the flow guiding cavity, and urea crystals are prevented from being formed by urea liquid drops in the mixed air flow deposited on the side wall surface due to the fact that the mixed air flow flowing through the grille opening impinges on the side wall surface of the rear shell.
Drawings
Fig. 1 is a perspective view of the present invention.
Fig. 2 is an exploded view of fig. 1.
Fig. 3 is a front view of fig. 1.
Fig. 4 is a right side view of fig. 1.
Fig. 5 is a cross-sectional view A-A of fig. 4.
Fig. 6 is a front view of the baffle.
Fig. 7 is a right side view of the baffle.
Fig. 8 is a perspective view of the orifice plate.
In the figure: 1. a front housing; 2. a rear housing; 3. an air inlet cylinder; 4. a nozzle holder; 5. a deflector; 6. an orifice plate; 7. a breaker plate; 8. an air outlet; 9. a front baffle; 10. a shielding plate; 11. a partition plate; 12. pit; 13. an internal cavity; 14. a spray chamber; 15. a mixing chamber; 16. a diversion cavity; 17. a first opening; 18. a second opening; 19. a blade; 20. a first through hole; 21. a second through hole; 22. a groove; 23. a grille opening; 24. an opening; 25. Spraying urea; 26. waist-receiving; 27. a circular arc section; 28. parallel sections; 29. an air inlet.
Detailed Description
The following describes specific embodiments of the present invention with reference to the drawings.
As shown in fig. 1, a front shell 1 of the present invention is fixed on a rear shell 2, an internal cavity 13 is formed between the front shell 1 and the rear shell 2, and the left and right sides of the middle parts of the front shell 1 and the rear shell 2 are respectively recessed inwards towards the internal cavity 13 to form a waisted structure. The upper part of the front shell 1 is provided with an air inlet cylinder 3, the lower part is provided with a cylindrical air outlet 8, and the air inlet cylinder 3 and the air outlet 8 are communicated with an internal cavity 13. As shown in fig. 2, a U-shaped partition plate 11 is fixedly arranged between the front housing 1 and the rear housing 2, and the partition plate 11 comprises an inner circular arc section 27 and an outer parallel section 28; the baffle 11 is welded on the rear shell 2, and the U-shaped inner part of the baffle 11 is fixed with the crushing plate 7; as shown in fig. 4, the partition plate 11 and the crushing plate 7 divide the internal cavity 13 into an injection cavity 14, a mixing cavity 15 and a diversion cavity 16, the injection cavity 14 is positioned inside the partition plate 11 and outside the crushing plate 7, the mixing cavity 15 is positioned between the crushing plate 7 and the circular arc section 27 of the partition plate 11, and the diversion cavity 16 is positioned outside the partition plate 11. As shown in fig. 1 and 2, the front end part of the baffle 11 is provided with a front baffle 9, the front baffle 9 is fixed on the front shell 1, a U-shaped opening 24 is formed in the front baffle 9 corresponding to the U-shaped baffle 11, a guide plate 5 and a pore plate 6 are embedded in the opening 24, the pore plate 6 is positioned in an arc section at the inner side of the opening 24, and the guide plate 5 is positioned in a parallel section 28 at the outer side of the opening 24; as shown in fig. 3, an air inlet 29 is formed between the outer side edge of the baffle 5 and the corresponding inner wall surface of the front case 1. The outer surface of the upper part of the rear shell 2 is opposite to the crushing plate 7, a pit 12 is concavely formed towards the inner cavity 13, a nozzle seat 4 is arranged on the bottom surface of the pit 12, a urea nozzle is arranged on the nozzle seat 4 (not shown in the figure), urea liquid drops can be sprayed into the spraying cavity 14, and urea spraying rays 25 are opposite to the crushing plate 7. As shown in fig. 2 and 5, a U-shaped shielding plate 10 with one open end and one closed end is fixedly arranged on the inner wall surface of the rear housing 2 corresponding to the pit 12, the closed end of the U-shaped shielding plate is positioned on one side of the air inlet cylinder 3, the shielding plate 10 shields the periphery of the urea nozzle on the nozzle seat 4, namely, the shielding plate 10 is arranged on the periphery of the nozzle seat 4 positioned on one side of the air inlet cylinder 3, so that the exhaust gas flow entering the air inlet cylinder 3 is shielded, and the exhaust gas flow is prevented from directly blowing the urea injection line 25, thereby blowing urea liquid drops onto the inner wall surface of the rear housing 2 to form urea crystals; as shown in fig. 3, the shielding plate 10 is correspondingly positioned at the inner side of the air inlet 29, and the exhaust air flow entering from the air inlet 29 can heat the shielding plate 10, so that urea drops falling on the shielding plate 10 absorb heat and volatilize sufficiently, and urea crystals are avoided.
As shown in fig. 4, the taper is arranged between the front end and the rear end of the rear housing 2, which can guide the input tail gas flow, is more beneficial to the uniform distribution of the tail gas flow in the internal cavity 13, and preheats each wall surface of the rear housing 2, so that urea drops falling on each wall surface fully absorb heat and volatilize, the evaporation rate of the urea drops is improved, and urea crystals are prevented from being formed on each wall surface. As shown in fig. 5, the left and right sides of the longitudinal middle part of the rear housing 2 are formed with waisted parts 26, and the cross-sectional dimensions of the waisted parts 26 are smaller than those of the upper and lower parts of the rear housing 2; when the mixed air flowing along the wall surface of the rear housing 2 passes through the waisted portion 26, the flow velocity of the mixed air can be increased due to the fact that the cross-sectional dimension is reduced, the accelerated mixed air enters the inner wall surface with the enlarged cross-sectional dimension along the inner wall surface of the waisted portion 26 to form swirl more easily, the swirl effect is better, the mixing effect of the mixed air is better, and the mixing uniformity is higher.
As shown in fig. 6 and 7, the deflector 5 is a square plate, and is correspondingly disposed at the front side of the parallel section 28 of the partition 11, and the exhaust gas flow is guided by the deflector 5 and enters the injection cavity 14. Two square first openings 17 and a plurality of strip square second openings 18 positioned on the inner sides and below the two first openings 17 are arranged on the guide plate 5 in an array manner, as shown in fig. 1, the long sides of the second openings 18 are perpendicular to the central axis direction of the nozzle seat 4. As shown in fig. 6 and 7, the second opening 18 is provided with the vane 19 along the long side direction, as shown in fig. 1 and 2, the vane 19 is opened inwards towards the spray cavity 14, the opening of the vane 19 is opposite to the crushing plate 7, and the mixed air flow can be guided to blow towards the crushing plate 7, on one hand, the mixed air flow can be prevented from directly blowing the urea spray line 25 to blow urea drops onto the inner wall surface of the rear housing 2 to form urea crystals, and the risk of urea crystallization on the rear housing 2 is reduced; on the other hand, the blades 19 guide the mixed air flow to blow to the crushing plate 7, so that the heat of the tail gas can be fully utilized, urea drops falling on the crushing plate 7 can fully absorb heat and volatilize, the volatilization rate of the urea drops is improved, and the conversion efficiency of NO X is further improved; in addition, the blade 19 has a breaking action on urea droplets, which break up into smaller droplets that are more volatile. The first opening 17 is free of blocking elements, the air flow channel is smooth, the air flow passing through the first opening 17 enters from two sides of the shielding plate 10, backflow of the air flow in the spraying cavity 14 can be reduced, and influence of backflow on the spraying direction of the urea spraying line 25 is avoided.
As shown in fig. 1 and 2, the orifice plate 6 is a semicircular arc plate, and is correspondingly arranged at the front side of the arc section 27 of the partition plate 11, and the exhaust gas flow is dispersed into the mixing cavity 15 through the orifice plate 6. The pore plate 6 is fully provided with a plurality of first through holes 20 in a staggered manner, the tail gas flow is dispersed into the mixing cavity 15 through the plurality of first through holes 20, the air inlet is more uniform, the tail gas flow is fully mixed with urea drops which are crushed and volatilized by the crushing plate 7, the urea drops are further volatilized by absorbing heat, the volatilization rate of the urea drops is improved, and the conversion efficiency of NO X is further improved.
As shown in fig. 8, the crushing plate 7 is an arc plate, the crushing plate 7 plays a role in scattering and crushing urea liquid drops, and the urea liquid drops are crushed into smaller liquid drops and are easier to volatilize; as shown in fig. 5, the circular arc shape of the circular arc-shaped section 27 of the baffle plate 11 protrudes towards the direction of the U-shaped circular arc section 27, namely the crushing plate 7 protrudes towards the direction away from the nozzle seat 4, so that the spraying space of the spraying cavity 14 can be increased, urea liquid drops and exhaust gas flow can be fully mixed, and the mixing performance is better; the bulge of the breaking plate 7 in the direction away from the nozzle holder 4 can also increase the area of the breaking wall surface of the urea droplets at the same time, so that the urea droplets are sufficiently broken into smaller droplets. As shown in fig. 8, the arc-shaped panel of the crushing plate 7 is alternately provided with a plurality of second through holes 21, and the mixed air flows through the plurality of second through holes 21, so that the mixed air is more fully mixed in the mixing cavity 15, and the mixing uniformity is higher; the crushing plate 7 is provided with grooves 22 at two outer sides corresponding to the partition plate 11 respectively, and the mixed air flow can flow downwards along the inner wall surface of the circular arc section 27 of the partition plate 11 after flowing through the grooves 22, so as to heat the inner wall surface of the circular arc section 27 of the partition plate 11, fully absorb heat and volatilize urea liquid drops falling on the inner wall surface of the circular arc section 27, and avoid forming urea crystals.
As shown in fig. 2, the arc section 27 of the partition plate 11 is opposite to the crushing plate 7, and the wall surface corresponding to one side of the diversion cavity 16 is provided with a plurality of grid openings 23 arranged in an array manner, and the grid openings 23 are positioned on the opposite side of the nozzle seat 4, so that on one hand, the grid openings 23 have a secondary crushing effect on urea liquid drops, the urea liquid drops are further crushed into smaller size, and the atomized and volatilized urea liquid drops are ensured to be more thorough; on the other hand, the mixed air in the mixing cavity 15 flows into the diversion cavity 16 through the grid opening 23, so that the flowing speed of the mixed air is not too fast, the mixed air is more favorable for being fully mixed, and the mixing uniformity is higher. The grille opening 23 is formed on a wall surface at one side of the diversion cavity 16, and can guide the mixed air flow to enter the diversion cavity 16 downwards, so that urea crystals are prevented from being formed by urea liquid drops in the mixed air flow deposited on the wall surface due to the mixed air flow flowing through the grille opening 23 impinging on the wall surface of the rear housing 2.
In actual use, the urea nozzle on the nozzle seat 4 sprays urea liquid drops into the spray cavity 14 to form urea spray lines 25; one part of the exhaust gas flow discharged by the engine is guided into the injection cavity 14 through the guide plate 5 and the air inlet 29, and the other part of the exhaust gas flow is dispersed into the mixing cavity 15 through the orifice plate 6; the urea liquid drops in the spray cavity 14 absorb the heat of the tail gas air flow to finish the first decomposition of the urea liquid drops and form a mixed air flow, the mixed air flow flows through the crushing plate 7 and enters the mixing cavity 15, the urea liquid drops which are not decomposed in the mixed air flow impact the crushing plate 7 and are crushed into urea liquid drops with smaller particles, the urea liquid drops further volatilize into the mixed air flow of the mixing cavity 15 after absorbing the heat, and the second decomposition and mixing of the urea liquid drops are finished; the mixed air flow in the mixing cavity 15 flows through the baffle plate 11 and enters the flow guiding cavity 16, after the undecomposed urea liquid drops in the mixed air flow impact on the grid openings 23 of the baffle plate 11, the urea liquid drops are further broken into urea liquid drops with smaller particles, the urea liquid drops are further volatilized after absorbing heat, and the urea liquid drops flow into the flow guiding cavity 16 along with the mixed air flow, so that the third decomposition and mixing of the urea liquid drops are completed; after the mixed gas flow in the flow guiding cavity 16 passes through the waist 26 of the rear shell 2, the mixed gas flow accelerates and forms a rotational flow, a mixing path is prolonged, volatilization and mixing time of urea liquid drops is prolonged, the urea liquid drops further absorb heat to volatilize into the gas flow, and after the third decomposition and mixing of the urea liquid drops are completed, the mixed gas flow is further uniformly mixed and then is output through the gas outlet 8 for subsequent treatment. The tail gas flow is decomposed and mixed for many times in the inner cavity 13, urea dropping liquid is fully decomposed, and decomposed ammonia gas and tail gas are fully mixed, so that the mixing uniformity is high, and the NO X conversion rate is high.
The above description is illustrative of the invention and is not intended to be limiting, and the invention may be modified in any form without departing from the spirit of the invention.
Claims (5)
1. An urea mixing device, forms inside cavity (13) between preceding shell (1) and back shell (2), preceding shell (1) upper portion has gas inlet cylinder (3), lower part have gas outlet (8), its characterized in that: a partition plate (11) is arranged between the front shell (1) and the rear shell (2), a crushing plate (7) is fixed on the partition plate (11), the partition plate (11) and the crushing plate (7) divide an internal cavity (13) into a spray cavity (14) positioned inside the partition plate (11) and outside the crushing plate (7), a mixing cavity (15) positioned between the crushing plate (7) and the partition plate (11) and a diversion cavity (16) positioned outside the partition plate (11);
The front end part of the baffle plate (11) is provided with a front baffle plate (9), an opening (24) is formed in the front baffle plate (9) corresponding to the baffle plate (11), a guide plate (5) and a pore plate (6) are arranged on the opening (24), and an air inlet (29) is formed between the outer side edge of the guide plate (5) and the inner wall surface corresponding to the front shell (1); the guide plate (5) is provided with a first opening (17) and a second opening (18), and the second opening (18) is provided with a blade (19) which is opened inwards towards the injection cavity (14); a plurality of first through holes (20) are formed in the pore plate (6);
a grid opening (23) is formed in the wall surface, opposite to the crushing plate (7), of the partition plate (11);
the middle part of the rear shell (2) in the longitudinal direction is inwards recessed towards the inner cavity (13) to form a waist-receiving part (26);
a pit (12) is concavely formed on the outer surface of the upper part of the rear shell (2), a nozzle seat (4) is arranged on the bottom surface of the pit (12), and a urea nozzle is arranged on the nozzle seat (4); a shielding plate (10) is fixedly arranged on the inner wall surface of the rear shell (2) corresponding to the pit (12), and the shielding plate (10) shields the periphery of the nozzle seat (4) positioned on one side of the air inlet cylinder (3);
The partition plate (11) is U-shaped and comprises a circular arc section (27) and a parallel section (28); the front baffle (9) is correspondingly provided with a U-shaped opening (24); the guide plate (5) is a square plate and is correspondingly arranged on the front side of the parallel section (28) of the partition plate (11); the openings of the blades (19) on the guide plate (5) are opposite to the crushing plate (7); the pore plate (6) is a semicircular arc plate and is correspondingly arranged on the front side of the arc section (27) of the partition plate (11); the crushing plate (7) is an arc-shaped plate, and the arc shape of the arc-shaped plate protrudes towards the direction of the arc section (27) of the partition plate (11).
2. The urea mixing device according to claim 1, wherein: the shielding plate (10) is positioned on the inner side of the air inlet (29).
3. The urea mixing device according to claim 1, wherein: the shielding plate (10) is U-shaped with one end open and one end closed.
4. The urea mixing device according to claim 1, wherein: grooves (22) are respectively formed in the two outer sides of the crushing plate (7) corresponding to the partition plates (11).
5. The urea mixing device according to claim 1, wherein: a plurality of grid openings (23) which are arranged in an array manner are arranged on the wall surface of the arc section (27) of the baffle plate (11) corresponding to one side of the diversion cavity (16).
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| CN112112718A (en) * | 2020-09-30 | 2020-12-22 | 无锡亿利环保科技有限公司 | Mixer of tail gas aftertreatment system |
| CN112855315A (en) * | 2021-02-05 | 2021-05-28 | 无锡亿利环保科技有限公司 | SCR urea mixer |
| CN113586212B (en) * | 2021-09-15 | 2022-11-22 | 无锡威孚力达催化净化器有限责任公司 | Mixing device with multi-cyclone structure |
| CN113914976B (en) * | 2021-11-15 | 2023-02-17 | 一汽解放汽车有限公司 | Engine and aftertreatment mixer thereof |
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| JP2007032472A (en) * | 2005-07-28 | 2007-02-08 | Hitachi Ltd | Exhaust gas treatment device using urea water |
| KR101498178B1 (en) * | 2014-11-25 | 2015-03-04 | 세종공업 주식회사 | Urea mixing apparatus having swirl unit |
| CN107461239A (en) * | 2016-06-03 | 2017-12-12 | 天纳克（苏州）排放系统有限公司 | Hybrid chamber component |
| CN108915830B (en) * | 2016-06-13 | 2019-11-08 | 天纳克（苏州）排放系统有限公司 | Exhaust aftertreatment mixing arrangement |
| CN108087067A (en) * | 2017-12-23 | 2018-05-29 | 无锡威孚力达催化净化器有限责任公司 | Eddy flow urea mixing device |
| CN108457727A (en) * | 2018-04-19 | 2018-08-28 | 凯德斯环保科技（苏州）有限公司 | SCR urea mixers |
| CN109538336A (en) * | 2019-01-11 | 2019-03-29 | 安徽艾可蓝环保股份有限公司 | A kind of novel mixer |
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