WO2008058548A1 - Tuyère et procédé pour l'atomisation de fluides - Google Patents

Tuyère et procédé pour l'atomisation de fluides Download PDF

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Publication number
WO2008058548A1
WO2008058548A1 PCT/DK2007/050170 DK2007050170W WO2008058548A1 WO 2008058548 A1 WO2008058548 A1 WO 2008058548A1 DK 2007050170 W DK2007050170 W DK 2007050170W WO 2008058548 A1 WO2008058548 A1 WO 2008058548A1
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WO
WIPO (PCT)
Prior art keywords
fluid
outlets
nozzle
flow
impinge
Prior art date
Application number
PCT/DK2007/050170
Other languages
English (en)
Inventor
Anders E. Jensen
Christian Boe
Niels Torp Madsen
Peter Rosenbeck Mortensen
Original Assignee
Grundfos Nonox A/S
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Grundfos Nonox A/S filed Critical Grundfos Nonox A/S
Publication of WO2008058548A1 publication Critical patent/WO2008058548A1/fr

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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
    • F01N3/18—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]
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
    • B05B1/00—Nozzles, spray heads or other outlets, with or without auxiliary devices such as valves, heating means
    • B05B1/14—Nozzles, spray heads or other outlets, with or without auxiliary devices such as valves, heating means with multiple outlet openings; with strainers in or outside the outlet opening
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
    • B05B1/00—Nozzles, spray heads or other outlets, with or without auxiliary devices such as valves, heating means
    • B05B1/26—Nozzles, spray heads or other outlets, with or without auxiliary devices such as valves, heating means with means for mechanically breaking-up or deflecting the jet after discharge, e.g. with fixed deflectors; Breaking-up the discharged liquid or other fluent material by impinging jets
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES 
    • F23J15/00—Arrangements of devices for treating smoke or fumes
    • F23J15/003—Arrangements of devices for treating smoke or fumes for supplying chemicals to fumes, e.g. using injection devices
    • 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
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23D—BURNERS
    • F23D2206/00—Burners for specific applications
    • F23D2206/10—Turbines
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES 
    • F23J2215/00—Preventing emissions
    • F23J2215/10—Nitrogen; Compounds thereof
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES 
    • F23J2219/00—Treatment devices
    • F23J2219/10—Catalytic reduction devices
    • 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

Definitions

  • the present invention relates to atomization of fluids, and in particular to atomization of fluids discharged from a nozzle.
  • Atomization of fluids is for instance carried out by mixing a fluid to be atomized with a gas.
  • a gas for atomization inevitably leads to introduction of this gas into the stream of atomized fluid, and in many practical implementations such a mix of fluids is highly undesirable.
  • atomization has previously been performed by use of pressurised air. In this connection it has been found that the presence of air will initiate growth of crystals which tend to block the flow passages. A further disadvantage is large air consumption.
  • An object of the present invention is to atomize one or more fluids, preferably liquids, being in the form of one or more fluid streams.
  • This object has been met by various aspects and preferred embodiments of the invention by which one or more fluid streams flow so that impingement of the fluid stream(s) occurs which impingement provides atomization of the fluid.
  • atomization is preferably meant that the fluid streams are decomposed into smaller units, such as droplets.
  • the fluid streams may e.g. have a cross section in the order of 0.1 mm 2 before impingement, and the resulting droplets after impingement between the fluid streams may have a cross section in the order of 0.01 mm 2 .
  • both smaller and larger values of the dimensions described are possible within the scope of the invention.
  • fluid is preferably meant a liquid or a gas.
  • embodiments according to the present invention may also be used to decompose solid particles into smaller particles.
  • fluid stream may be understood to include the meaning “a stream of solid particles” that are to be decomposed into smaller units.
  • the present invention relates in a first aspect to a method for atomization of one or more fluids, the method comprising leading pressurised fluid(s) through one or more outlets of a nozzle, each outlet having an orientation so that fluid streams discharged from the one or more outlets impinge so as to provide an atomization of the fluid, wherein the atomization is carried out in an exhaust system of a combustion engine or gas turbine, preferably being a diesel combustion engine.
  • this wording also covers an outlet generating a fluid stream being conical and tapering in downstream direction so that the stream of fluid flowing through the outlet impinges.
  • at least some of the fluid stream(s) impinge at the outlets are examples of the outlets.
  • impinge is preferably meant that the fluid stream hits, i.e. impinges, another fluid stream - or for some embodiments that parts of one fluid stream hits other parts of the same fluid stream.
  • the fluid streams may additionally impinge other elements, such as a wall of a pipe into which the fluid streams.
  • the nozzle may comprise an end surface, and at least two outlets are arranged as intersecting channels.
  • the intersection may preferably be positioned above said surface, at said surface and/or inside the nozzle.
  • the nozzle may preferably further comprise a droplet outlet channel.
  • the one or more of the outlets are connected to a flow system comprising one or more shut off valves.
  • the fluid is preferably led through the one or more outlets intermittently, in a pulsating manner, in a continuous manner or a combination thereof. This has the advantage that the amount of fluid atomized may easily be controlled.
  • the intermittent and/or pulsating leading of fluid through the one or more outlets are provided by opening and closing the one or more shut off valves.
  • the fluid is preferably being led through the one or more outlets in a synchronised manner as this may assure impingement and thereby atomization.
  • the fluid streams impinging one another have substantially the same kinetic energy as this may assure a spray of atomized fluid that is not lopsided. Additionally or in combination thereto, fluid streams impinging one another preferably have substantially the same mass flow and velocity.
  • At least two fluid streams exiting the one or more outlets flow in one plane. This may provide an effective atomization as the fluid streams may impinge each other centrally.
  • the method according to the present invention may preferably comprise leading pressurised fluid selectively through some or all outlets of a plurality of outlets, such as four, five, six, seven, eight, nine, ten or more outlets, in such a manner that the amount of fluid atomized is varied by leading fluid through some or all of the outlets. Thereby the amount of fluid being atomized may be controlled.
  • the one or more outlets are preferably arranged so that at least two atomized sprays are provided.
  • the at least two sprays are preferably provided by the orientation of the outlets so that they travel in directions being either parallel or crossing.
  • the fluid to be atomized is preferably urea or a fluid which can react in a similar manner as urea with NOx to provide a selective catalytic reduction.
  • the fluid may also be diesel.
  • the atomization of the urea results in a better mixing of the urea with the exhaust gas than when the urea is supplied in other forms, such as in a stream or as larger droplets.
  • the atomization means that the chemical reaction between the urea and the NO x gasses can be improved, and the discharge of NO x gasses to the environment can thereby be minimised.
  • the first aspect of the invention is advantageously carried out by one or more nozzles according to the second aspect of the invention.
  • the present invention relates in a second aspect to a nozzle for atomization of one or more fluids, said nozzle comprising an inlet and one or more outlets, said one or more outlets being arranged in an exhaust system of a combustion engine or gas turbine, preferably being a diesel combustion engine, so that fluid stream(s) discharged from the one or more outlets impinge so as to provide an atomization of the fluid.
  • a combustion engine or gas turbine preferably being a diesel combustion engine
  • the nozzle comprises an end surface, and at least two outlets may preferably be arranged as intersecting channels, and the intersection may preferably be arranged above said surface, at said surface and/or inside the nozzle.
  • the nozzle may preferably further comprise a droplet outlet channel.
  • the nozzle may comprise at least two outlets being arranged so that fluid stream discharged from one of the outlets impinges fluid stream discharged from another of the outlets.
  • the nozzle may comprise at least three, such as at least four, such as at least five, such as at least six outlets.
  • All outlets are preferably connected to the inlet by intermediate flow channels dividing and leading the fluid entering the nozzle to the outlet.
  • the intermediate flow channels lead and divide the fluid to the outlets in a substantially uniform manner.
  • the cross sections of the flow channels may have any shape, such as circular or quadratic. Furthermore the cross section may be the same along the whole flow path, or it may vary in shape and/or size.
  • the cross section of the flow channels may be designed to establish a build up of the pressure in the fluid by having a larger total flow channel cross section area at the inlet of the nozzle than at the exit end.
  • the outlets are preferably arranged so that fluid streams discharged from at least two outlets impinge each other at an angle of between 30 and 100°, such as between 70 and 95°, preferably 80°.
  • the angles may be the same for all outlet flow channels of a nozzle, but the outlet flow channels may also be arranged so that some fluid streams impinge at one angle and others impinge at at least one more angle.
  • the angles may be fixed or variable, with a variable angle e.g. being established by letting the nozzle comprise closing means whereby some of the outlet flow channels can be blocked.
  • the one or more of the outlets are preferably defined by the termination of a bore defining an outlet flow channel being in fluid communication with the inlet.
  • These outlet channels may preferably be connected to the inlet by the intermediate flow channels or to a cavity of the nozzle, the cavity being in fluid communication with the inlet channel.
  • the cross sectional area of each of the fluid streams discharged from the outlets is in the range of 0.003-0.15 mm 2 , preferably in the range of 0.005 to 0.05 mm 2 , such as in the range of 0.01 to 0.03 mm 2 , preferably 0.02 mm 2 .
  • the nozzle comprises at least four outlets wherein two of the outlets are arranged so that fluid discharged there from impinges at a first angle and wherein two other outlets are arranged so that fluid discharged there from impinges at a second angle, the first and the second angles being different from each other.
  • the nozzle may comprise any number of outlet flow channels arranged so that the fluid streams discharged there from impinge pair wise, or in groups of three or more, at any number of angles.
  • the one or more outlets comprise(s) a slot arranged so that the fluid exiting the nozzle will exit in a fluid stream having conical shape tapering in the stream wise direction.
  • the slot may be provided as a conical bore and a corresponding conical member arranged within the bore.
  • the conical member may be adjustably arranged so that the longitudinal position of the member can be adjusted whereby the size of the slot can be adjusted. This provides the possibility of adjusting the amount of fluid exiting the nozzle.
  • the member may furthermore comprise additional outlet flow channels.
  • the nozzle according to the present invention may comprise filtering and/or heating means. These means may be used to filter and/or heat one or more fluids being led through the nozzle.
  • the nozzle according to the present invention may further comprise one or more valve means.
  • Such valve means may be adapted to shut off the flow through one or more of the outlets so as to control the amount of fluid being atomized and/or to fully shut off for fluid flow through the nozzle.
  • a pulsating and/or intermittent flow through the nozzle may be provided.
  • a system for mixing liquid urea or a fluid which can react in a similar manner as urea with NOx to provide a selective catalytic reduction with the exhaust gasses from a combustion engine or gas turbine is provided.
  • the urea or a fluid which can react in a similar manner as urea with NOx to provide a selective catalytic reduction is added and atomized within the exhaust gasses by use of a nozzle as described above.
  • the nozzle may be arranged in the centre of a pipe of an exhaust system of a combustion engine or gas turbine.
  • a plurality of nozzles may be circumferentially distributed along the wall of a pipe of an exhaust system of a combustion engine.
  • the one or more nozzle may be arranged so as to deliver atomized fluid in the stream wise or in any other direction of the exhaust gasses, such as perpendicular to the stream wise direction.
  • the one or more nozzles may be placed at any position with respect to the pipe of an exhaust system within the scope of the invention.
  • Fig. 1 shows schematically the overall principle of atomizing a fluid by letting two streams of fluid impinge.
  • Fig. 2 shows schematically an embodiment of the present invention in which two impinging streams of fluid are provided by two separate pumps
  • Fig. 3 shows schematically a cross sectional view of an embodiment of the present invention in which two impinging streams of fluid are provided by a single nozzle
  • Fig. 4a shows schematically a part of the flow channels
  • fig. 4.b and 4.c show schematically impinging or non-impinging fluid streams during intermittent flow conditions
  • Fig. 5 shows schematically another embodiment of the invention in which the fluid flows through more than two channels
  • Fig. 6 shows different possible positions of the outlets of the flow channels on the outlet end of the nozzle. The view is towards the outlet end of nozzles according to different embodiments of the invention.
  • Fig. 7 shows schematically an embodiment of the invention in which the fluid streams impinge at different distances from the outlet end surface of the nozzle
  • Fig. 8 shows schematically an embodiment of the invention in which the outlet is provided as an annular slot
  • Fig. 9 shows schematically one possible application of the invention, wherein it is used for atomization of urea added to the exhaust gas of a combustion engine or gas turbine,
  • Fig. s 10-13 shows schematically sections around the outlet of different embodiments according to the present invention
  • Fig. 14 shows an alternative embodiment wherein the flow channels are established by joining two or more members of which one or more contain(s) grooves which constitute the channels, and
  • Fig. 15 shows schematically three designs of a groove-containing member, called a channel spacer in fig. 14.
  • Fig. 1 shows schematically the overall principle of atomizing a fluid by letting two streams of fluid impinge. The flow directions are indicated by arrows.
  • the fluid is divided in a number of streams - in the example shown in fig. 1 into two streams - each given kinetic energy.
  • the amount of kinetic energy given to streams is so that when the streams impinge at conditions where substantially opposite directed velocity components of the streams exist, the streams will break up into a spray having a small droplet size shown as dots in the figures.
  • This is in the present context referred to atomizing.
  • It is essential to the atomizing process that the streams of fluid "hit" each other centrally, e.g. in the example of fig. 1 that the two streams of fluid is within the plane, if one aims at providing a best possible atomization.
  • a balance between the streams' mass flow and velocity should be present to provide a spray that is not lopsided.
  • the magnitude of the oppositely directed velocity components depends, among other factors, on the angle between the fluid streams. If the angle is small, e.g. 60°, the atomization of the fluid stream is lesser and the resulting spray will have a substantial velocity in the direction of the vector sum of the velocities of the fluid streams. If the angle is large, e.g. 120°, small droplets are hurled upstream the direction the fluid stream - this is indicated in fig. 1. In case the fluid streams are provided by a nozzle, the hurling back of droplets may result in depositing of fluid on the nozzle as fluid film and/or droplets.
  • Fig. 2 shows schematically the scenario disclosed in connection with fig. 1 where the two fluid streams are provided by two separate but similar, such as identical, pumps P providing two streams of fluid streaming towards each other.
  • the two pumps provide fluid streams with equal kinetic energy.
  • Fig. 3 shows schematically the overall principle of atomizing a fluid by leading the flow of fluid through two channels arranged so that the exiting fluid streams impinge one another whereby the fluid is atomized.
  • the fluid is illustrated as being supplied from one fluid line, which typically is pressurized. However, the invention may also be used to atomize and at the same time mix two or more different fluids led to the nozzle from different fluid supplies.
  • the nozzle 1 comprises an inlet channel 2 through which the fluid to be atomized is fed into the nozzle 1.
  • the inlet channel 2 bifurcate at position a in fig. 3 into two intermediate flow channels 3a and 3b leading the fluid into two distinct outlet flow channels 4a and 4b.
  • the channels 2, 3 and 4 constitute flow channels defining a flow path from the inlet 5 of the nozzle 1 to the outlets 6a and 6b of the nozzle. As shown in fig. 3, the outlet flow channels 4a and 4b are continuations of the intermediate flow channels 3a and 3b.
  • Effective ways to avoid depositing due to back spray is to keep areas which may be subjected to back spray wetted by a stream of fluid and/or to assure that back sprayed droplets deposit on surfaces e.g. the end surface 7 not defining, at least directly, the flow out of the outlets.
  • the two outlets 6a and 6b are arranged in the nozzle 1 so that the two streams of fluid impinge at the outlets 6a and 6b. This is provided by arranging the outlets as two channels intersecting at the end surface 7. In this embodiment, little back spray may occur and droplets may deposit on the end surface 7 of the nozzle. Such a depositing is not considered to be destructive for the formation of droplets.
  • droplets may back spray into the outlets 6a and 6b. However, these outlets 6a and 6b are kept wet by the fluid being fed to the nozzle whereby such droplets will be absorbed by the fluid.
  • the droplets formed will primarily be given a velocity out of the nozzle whereby back spray will be avoided or at least limited. Further examples will be given in the following and in particular with the description of fig.s 10-13.
  • the outlet flow channels 4a and 4b and the outlets 6a and 6b all have a rectangular or circular cross section, and in order to arrange the two outlets 6a and 6b so that the fluid streams impinge at the outlets 6a and 6b, the two outlets 6a and 6b run together and are joint at their termination as indicated in fig. 3.
  • the outlets 6a and 6b are a part of the outlet flow channels 4a and 4b.
  • the outlets are preferably defined as the part of the flow channels providing the orientation of the fluid streams, these flow channels often have the smallest cross sections of the nozzle's flow channels.
  • a balance between the two fluid streams should exist in order to provide a spray not being lopsided. It should preferably be assured that in embodiments like the one disclosed in fig. 3, the flow resistance between the bifurcation point a and the outlets 6a and 6b and the dimensions thereof, respectively, are made of equal size for the two flow paths. Hereby, the velocity and mass flow for the two fluid streams will become similar, such as equal.
  • the cross sections of the flow channels may have any shape which may be related to the actual manufacturing process used for making the nozzle.
  • the cross section is preferably circular, and the dimensions mentioned in the following then refer to the diameter of the cross section. For other shapes, the dimensions refer to a characteristic measure, such as the side length of a quadratic cross section.
  • the dimensions of the flow channels 2, 3 and 4 are chosen according to the actual use of the nozzle and thereby the amount of fluid to be atomized.
  • the cross sections of the channels are circular with a diameter in the order of 0.1 mm.
  • the amount of fluid exiting the nozzle will to a large extent be determined by the size of the outlets 6a and 6b and the pressure difference across the outlets 6a and 6b. It is therefore envisaged that the channels 2, 3 and 4 may have a larger cross section than the outlets 6a, 6b and provide an amount of fluid to be atomized being determined by the pressure difference across the outlets 6a, 6b and the cross sectional area thereof.
  • the impinging fluid streams should, as discussed above, have sufficient kinetic energy in order to be atomized.
  • the mass flow being atomized will typically vary at least an order of magnitude such that the minimum mass flow may be as low as 1% of the maximum mass flow. At low mass flow, the kinetic energy may be so small that no or only very little atomization occurs.
  • the amount of energy per mass unit present in the fluid streams would be less than 0.01% of the amount of energy present in the fluid streams at maximum mass flow. Such a small amount of energy would be insufficient to atomize the fluid.
  • Fig. 4. a shows schematically the design of a part of the flow channels
  • fig. 4.b and 4.c show schematically two situations in which intermittent flow streams, indicated by arrows, are not properly synchronised.
  • Fig. 4.b shows an example of a pulse start
  • fig. 4.c shows an example of pulse stop.
  • one or more nozzle(s) according to the present invention is/are connected to a pressurised source of fluid via a valve, typically a magnetic valve.
  • a valve typically a magnetic valve.
  • the valve is included in the nozzle(s).
  • the flow path between the source and the outlets of the nozzle(s) are in general not ideally stiff due to elasticity in pipes, fitting, sealings etc. and small gas bubble present in the flow path. If the elasticity is too large, for instance due to soft connections and larger gas bubbles, the pressure in the flow path will decrease too slowly at closing off the fluid flow, and fluid will continue to flow but with a too small kinetic energy to provide an atomization. This will result in generation of droplets on the surface of the nozzle close to the outlets of the nozzle. If the elasticity is larger, the flow will stop rapidly and an underpressure will be created by deceleration which will be able to suck a fluid accumulated outside the nozzle back into the nozzle so that formation of droplets is avoided.
  • the inlet channel 2 may, instead of comprising the bifurcation point, be made up by of a cavity within the nozzle, said cavity being in fluid communication with the inlet 5 via an inlet channel similar to the one shown in fig. 3.
  • An example of such a cavity 2a is illustrated in fig. 8.
  • the cavity is also in fluid communication with outlet flow channels similar to the ones shown in fig. 3.
  • the nozzle may e.g. be made from steel, aluminium, plastic or ceramic depending on the actual use, and any type of material is possible within the scope of the invention.
  • the choice of material will depend on a number of parameters including the operation temperature of the nozzle, the manufacturing technology used for manufacturing the nozzle, the chemical resistance against the fluid, and the flow rate and thereby the resulting wear rate.
  • the outlet flow channels may have varying cross sections along the flow path, such as being conical either with an increasing or decreasing cross sectional area in the stream wise direction.
  • cross section of an outlet flow channel is circular, its diameter will correspond to the diameter of a fluid stream being discharged there from.
  • a flow channel is conical, the diameter at the end of the outlet flow channel will differ from a fluid stream being discharged there from.
  • the angle, ⁇ , between the outlet flow channels 4 is illustrated as being approximately 80° but other angles, such as 30°, 60° or 120°, may also be used.
  • the angles may be either acute or obtuse.
  • the angles may be either fixed or variable. Variable angles may e.g. be obtained by letting the nozzle 1 comprise outlet flow channels 4 with different angles and furthermore comprise closing means (not shown) that can be used to block some of the channels.
  • the nozzle 1 may additionally comprise other means (not shown), such as filtering means and/or heating means for heating the fluid.
  • the purpose of such heating may be to improve the atomization but it may also be related to an actual use of the fluid. It may e.g. be desired to heat the fluid if that improves a chemical process between the fluid and another component, such as a gas or liquid.
  • the nozzle 1 may comprise one or more valves - or the fluid fed to the nozzle may be fed through one or more valves - adapted to shut off flow through one or more of the outlets 6.
  • the valve(s) may be adapted to shut off flow through one of the sets of outlets independently of flow through the other set of outlets. Thereby the amount of fluid being atomized can easily be controlled.
  • the amount of fluid being atomized can also be controlled by operating the valve(s) to provide a pulsating flow of fluid and/or by feeding the fluid intermittently through the nozzle. This can be done by successively opening and closing the valve(s) so as to successively allow and prevent fluid to flow through the nozzle.
  • Such a controlling is particularly useful when small amounts of fluid are to be atomized as such a pulsation will generate fluid streams of sufficient strength so that the impingement will result in atomization (see also the previous discussion of this issue above). This can advantageously be exploited in cases where the nozzle is operating in conditions where the demand for atomized fluid is not constant.
  • Fig. 5 illustrates schematically an embodiment of the invention comprising four flow channels 3.
  • the fluid streams impinge one another pair wise, but streams from three or more outlet flow channels 4 may also impinge. It is also possible to have some of the streams impinging pair wise and others impinging in groups of three or more. In one embodiment of the invention, all fluid streams except one impinge the one fluid stream.
  • the nozzle 1 comprising the flow channels 3,4 may be designed so that the outlets 6 of the channels are positioned to enable that the atomization takes place over a larger area than when there are only two outlet channels.
  • Two possible designs and amounts of outlet flow channels are illustrated schematically in fig. 6 which shows the end surface of the nozzle. This may be advantageous for applications in which only one fluid is to be atomized, but the embodiment can also be used to atomize two or more fluids before or at the same time as they are mixed.
  • the nozzle may be designed so that all the fluid streams impinge with one or more other fluid streams at the same distance from the end surface 7 of the nozzle 1 as shown in fig. 5. However, it may also be designed to ensure that the fluid streams impinge at different distances from the end surface 7 of the nozzle as illustrated schematically in fig. 7, where two streams of fluid impinge at the end surface 7 of the nozzle generating a downward streaming fluid into which two other streams of fluid are impinging at a position downstream of the end surface 7. This can be obtained both by having different angles or different distances between the outlet flow channels 4 from which the fluid streams impinge as illustrated schematically in fig. 7. Hereby it may be possible to improve the atomization and/or the mixing of the fluid streams.
  • outlets may be constituted by an annular/circular slot 8 as shown schematically in fig. 8.
  • the slot 8 may be provided as a conical bore 9 and a corresponding conical member 10 arranged within the bore.
  • the fluid exiting the slot 8 will exit the nozzle 1 in a tapering conical shape.
  • the conical member 10 may be adjustably arranged so that the longitudinal position of the member can be adjusted, whereby the size of the slot 8 can be adjusted. This provides the possibility of adjusting the amount of fluid exiting the nozzle 1.
  • the nozzle is made of a flexible material.
  • the use of flexible material will provide the effect that the cross sectional area of the outlets will depend on the pressure within the nozzle. The result is that a relatively high pressure will provide a high cross sectional area allowing a relatively large amount of fluid to flow out the outlets. A relatively smaller pressure within the nozzle will provide a relatively smaller cross sectional area allowing a relatively smaller amount of fluid to flow out the outlets.
  • Such a nozzle could preferably be made of a heat resistant material such as silicone.
  • the outlet flow channels are constituted by cannula pipes.
  • cannula pipes are embedded in for instance a plastic material or are soldered or glued to metal pieces and connected to a feeding channel system feeding fluid to be atomized to the cannula pipes.
  • nozzles according to the present invention may be done in a number of ways.
  • more than one nozzle may be used to fulfil a given requirement as to fluid to be atomized and as to distribution of the atomized fluid.
  • two nozzles may be arranged so that the atomized fluid from each nozzle streams into each other.
  • two or more nozzles may be used to control the amount of fluid to be atomized by utilising all nozzles at maximum need, turning nozzles off as the need for atomized fluid decreases, and turning nozzles on as the need for atomized fluid increases.
  • the nozzles may be different in the sense that the amount of atomized fluid each nozzle is capable of providing may be different from nozzle to nozzle involved - however, the nozzles may also be identical.
  • the present invention may find use in a number of applications in which atomization of a fluid is desired.
  • a combustion engine such as a Diesel engine as illustrated schematically in fig. 9.
  • the figure shows a system comprising a combustion engine 11 preferably working according to the Diesel principle, a tank 12 holding a liquid solution of urea (e.g. as known under the trade name AdBlue) and a catalytic system 13.
  • the exhaust of the engine 11 is connected to the catalytic system 13 by an exhaust pipe 14 which is connected to the tank 12 holding the liquid solution of urea.
  • the diameter of the exhaust pipe may typically be between 20 and 250 mm, such as e.g.
  • the system further comprises a metering unit 15 for feeding the urea into the exhaust system so that it may react with the exhaust gasses for minimisation of the discharge of NO x gasses to the environment.
  • a nozzle 1 according to the present invention is used to atomize the urea before it is added to the exhaust gasses, the nozzle may be comprised in a separate unit (not shown) mounted after the metering unit 15 at any position along the pipe 16, typically having a diameter of around 4 mm, leading the urea to the exhaust gas. Alternatively it may be integrated with the metering unit 15.
  • Another application of the invention is for atomization of diesel in the exhaust system in order to regenerate particle filters.
  • the metering unit 15 is preferable placed so that the atomized urea is mixed with the exhaust gas directly after leaving the nozzle 1.
  • the nozzle is typically arranged so that the fluid exiting the nozzle is sprayed into the stream of exhaust gasses in a stream wise or in any other direction of the exhaust gasses, this direction not necessarily being parallel with the stream wise direction of the exhaust gas, such as perpendicular to the stream wise direction.
  • the nozzle may be arranged in the centre of a pipe of an exhaust system of a combustion engine or gas turbine and/or in wall of the piping of the exhaust system.
  • a plurality of nozzles may be circumferentially distributed along the wall of a pipe of an exhaust system of a combustion engine.
  • the one or more nozzles may be placed at any position with respect to the pipe of an exhaust system within the scope of the invention.
  • the nozzle 1 is typically arranged within the exhaust system in such a manner that an even distribution of atomized gas in the exhaust gasses is provided in order to assure that atomized fluid will be distributed evenly within the catalytic system 13.
  • the nozzle may accordingly be arranged in the centre of the piping 14 of fig. 9 with its outlets facing in the stream wise direction of (but not necessarily parallel with) the exhaust gas.
  • a plurality of nozzles can be arranged in the exhaust system.
  • Such a plurality of nozzles will preferably be arranged circumferentially and in some cases evenly distributed.
  • the nozzles may also be distributed along the stream wise direction of the exhaust gases.
  • the outlets of such nozzles are preferably arranged with the outlets facing in the stream wise direction of (but not necessarily parallel with) the exhaust gas. It should be noted that a combination of nozzles being arranged circumferentially, in the stream wise direction, and/or one or more nozzles arranged in the centre of the piping is within the scope of the present invention.
  • Fig. s 10-13 show schematically different configurations of the outlet flow channels and the outlets.
  • the outlet flow channels 4a, 4b and the outlets 6a, 6b are intersecting at position 17 as indicted in these figures.
  • the outlets are arranged so that the intersection 17 is located outside the nozzle, e.g. outside the end surface 7 of the nozzle 1, whereas the intersection 17 in fig. 11 is located in the plane of the end surface 7 of the nozzle 1.
  • the end surface is depicted as a straight plane, it may have another shape such as tapered, rounded and the like. In this case the intersection is located in the plane of the end surface in the region of the outlets 6a and 6b.
  • the flow channels 4a, 4b and the outlets 6a, 6b extend so that the intersection 17 is arranged inside the nozzle.
  • the intersection 17 is retracted to such an extent that an outflow of droplets is provided from droplet outlet channel 19.
  • back spray is substantially avoided outside the nozzle as droplets leaving the nozzle substantially only have a velocity perpendicular to the end surface 7 and out of the nozzle. If back spray should occur inside the nozzle, for instance in connection with the embodiment of fig. 12, back sprayed droplets are sprayed into the fluid flowing through the channels 4a, 4b whereby depositing of back sprayed droplets is avoided.
  • the flow channels are shown as being provided in one solid block of material.
  • the flow channels are established by joining two or more members of which one or more contain(s) grooves which constitute the channels.
  • An example of such an embodiment is shown schematically in fig. 14.
  • the nozzle 1 comprises a first member 20, a second member 21, and a channel spacer 22.
  • the holes 23 shown in the channel spacer 22 are for guides for controlling of the positioning of the elements in correct, aligned relationship or for retaining means, such as screws (not shown).
  • the first member 20 comprises an inlet channel 2, whereas the intermediate flow channels 3a, 3b and the outlet flow channels 4a, 4b are illustrated as being formed by the first member 20, the second member 21 and the channel spacer 22 in combination. Reference numbers are only shown for the first member 20 for clarity.
  • the fluid atomizes when the two fluid streams impinge at a distance from the outlets 6a, 6b.
  • fig.s. 10-13 it is also for the embodiment in fig. 14 possible to have different configurations of the outlet flow channels 4a, 4b and the outlets 6a, 6b. This is shown schematically in fig. 15 where three possible designs of a channel spacer 22 are illustrated.
  • the shapes of the channels in the first and second members 20,21 must be designed accordingly.
  • the invention can be fitted in new or retrofitted in already existing HD-diesel engines or gas engines on trucks, buses, trains, mining equipment, construction equipment, ships airplanes, and generators.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Health & Medical Sciences (AREA)
  • Toxicology (AREA)
  • Combustion & Propulsion (AREA)
  • General Chemical & Material Sciences (AREA)
  • Exhaust Gas After Treatment (AREA)
  • Nozzles (AREA)

Abstract

La présente invention concerne un procédé et une tuyère pour l'atomisation d'un ou plusieurs fluides qui sont conduits à travers une ou plusieurs sorties (6a, 6b) d'une tuyère (1). Chaque sortie possède une orientation de sorte qu'un ou des courants de fluide déchargés à partir d'une ou de plusieurs sorties entrent en contact afin de fournir une atomisation du fluide. L'atomisation est réalisée dans un système d'échappement d'un moteur à combustion (11) ou une turbine à gaz, de préférence un moteur à combustion diesel. L'invention concerne en outre un système pour mélanger de l'urée liquide ou un fluide qui peut réagir de manière similaire à l'urée avec du NOx pour fournir une réduction catalytique sélective avec le gaz d'échappement à partir d'un moteur à combustion (11) ou une turbine à gaz. L'urée ou un fluide qui peut réagir de manière similaire à l'urée avec du NOx pour fournir une réduction catalytique sélective est ajouté et atomisé à l'intérieur du gaz d'échappement en utilisant une ou plusieurs tuyères.
PCT/DK2007/050170 2006-11-16 2007-11-16 Tuyère et procédé pour l'atomisation de fluides WO2008058548A1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
DKPA200601505 2006-11-16
DKPA200601506 2006-11-16
DKPA200601506 2006-11-16
DKPA200601505 2006-11-16

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WO2008058548A1 true WO2008058548A1 (fr) 2008-05-22

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105749828A (zh) * 2014-12-20 2016-07-13 中国石油化工股份有限公司 一种液相撞击流反应器
WO2017167798A1 (fr) * 2016-03-30 2017-10-05 Universiteit Twente Procédé et dispositif pour la production dans l'air de gouttelettes individuelles, de gouttelettes de composé et de particules ou fibres (de composé) à forme contrôlée
US9950328B2 (en) 2016-03-23 2018-04-24 Alfa Laval Corporate Ab Apparatus for dispersing particles in a fluid
US10857507B2 (en) 2016-03-23 2020-12-08 Alfa Laval Corporate Ab Apparatus for dispersing particles in a liquid

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0864732A1 (fr) * 1997-03-13 1998-09-16 Haldor Topsoe A/S Procédé de réduction sélective de NOx dans les gaz d'échappement
US20030079520A1 (en) * 2001-08-06 2003-05-01 Ingalls Melvin N. Method and apparatus for testing catalytic converter durability
DE102004056896A1 (de) * 2004-11-25 2006-06-01 Robert Bosch Gmbh Gasbeaufschlagungsvorrichtung

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0864732A1 (fr) * 1997-03-13 1998-09-16 Haldor Topsoe A/S Procédé de réduction sélective de NOx dans les gaz d'échappement
US20030079520A1 (en) * 2001-08-06 2003-05-01 Ingalls Melvin N. Method and apparatus for testing catalytic converter durability
DE102004056896A1 (de) * 2004-11-25 2006-06-01 Robert Bosch Gmbh Gasbeaufschlagungsvorrichtung

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105749828A (zh) * 2014-12-20 2016-07-13 中国石油化工股份有限公司 一种液相撞击流反应器
CN105749828B (zh) * 2014-12-20 2018-04-10 中国石油化工股份有限公司 一种液相撞击流反应器
US9950328B2 (en) 2016-03-23 2018-04-24 Alfa Laval Corporate Ab Apparatus for dispersing particles in a fluid
US10857507B2 (en) 2016-03-23 2020-12-08 Alfa Laval Corporate Ab Apparatus for dispersing particles in a liquid
WO2017167798A1 (fr) * 2016-03-30 2017-10-05 Universiteit Twente Procédé et dispositif pour la production dans l'air de gouttelettes individuelles, de gouttelettes de composé et de particules ou fibres (de composé) à forme contrôlée
EP3791953A1 (fr) * 2016-03-30 2021-03-17 IamFluidics Holding B.V. Procédé et dispositif de production dans l'air de gouttelettes uniques, composé de gouttelettes et particules ou des fibres (composé) à forme contrôlée
US11198293B2 (en) 2016-03-30 2021-12-14 Iamfluidics Holding B.V. Process and device for in-air production of single droplets, compound droplets, and shape-controlled (compound) particles or fibers
EP4000724A1 (fr) * 2016-03-30 2022-05-25 IamFluidics Holding B.V. Procédé et dispositif de production dans l'air de gouttelettes uniques, composé de gouttelettes et particules ou des fibres (composé) à forme contrôlée
US11850851B2 (en) 2016-03-30 2023-12-26 Iamfluidics Holding B.V. Process and device for in-air production of single droplets, compound droplets, and shape-controlled (compound) particles or fibers
US11850852B2 (en) 2016-03-30 2023-12-26 Iamfluidics Holding B.V. Process and device for in-air production of single droplets, compound droplets, and shape-controlled (compound) particles or fibers

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