EP0491079B1 - Burner head for premix combustion of a liquid fuel in an atmospheric combustion installation - Google Patents

Burner head for premix combustion of a liquid fuel in an atmospheric combustion installation Download PDF

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Publication number
EP0491079B1
EP0491079B1 EP90124798A EP90124798A EP0491079B1 EP 0491079 B1 EP0491079 B1 EP 0491079B1 EP 90124798 A EP90124798 A EP 90124798A EP 90124798 A EP90124798 A EP 90124798A EP 0491079 B1 EP0491079 B1 EP 0491079B1
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EP
European Patent Office
Prior art keywords
combustion
burner head
zone
premixing
air duct
Prior art date
Legal status (The legal status 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 status listed.)
Expired - Lifetime
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EP90124798A
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German (de)
French (fr)
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EP0491079A1 (en
Inventor
Hans Peter Knöpfel
Claude Pelet
Hans Peter
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
ABB Asea Brown Boveri Ltd
ABB AB
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ABB Asea Brown Boveri Ltd
Asea Brown Boveri AB
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Application filed by ABB Asea Brown Boveri Ltd, Asea Brown Boveri AB filed Critical ABB Asea Brown Boveri Ltd
Priority to EP90124798A priority Critical patent/EP0491079B1/en
Priority to DE59010544T priority patent/DE59010544D1/en
Priority to AT90124798T priority patent/ATE144316T1/en
Publication of EP0491079A1 publication Critical patent/EP0491079A1/en
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Publication of EP0491079B1 publication Critical patent/EP0491079B1/en
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    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23CMETHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN  A CARRIER GAS OR AIR 
    • F23C7/00Combustion apparatus characterised by arrangements for air supply
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23CMETHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN  A CARRIER GAS OR AIR 
    • F23C9/00Combustion apparatus characterised by arrangements for returning combustion products or flue gases to the combustion chamber
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23DBURNERS
    • F23D11/00Burners using a direct spraying action of liquid droplets or vaporised liquid into the combustion space
    • F23D11/36Details, e.g. burner cooling means, noise reduction means
    • F23D11/40Mixing tubes or chambers; Burner heads
    • F23D11/402Mixing chambers downstream of the nozzle
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23CMETHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN  A CARRIER GAS OR AIR 
    • F23C2900/00Special features of, or arrangements for combustion apparatus using fluid fuels or solid fuels suspended in air; Combustion processes therefor
    • F23C2900/06041Staged supply of oxidant
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23CMETHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN  A CARRIER GAS OR AIR 
    • F23C2900/00Special features of, or arrangements for combustion apparatus using fluid fuels or solid fuels suspended in air; Combustion processes therefor
    • F23C2900/09002Specific devices inducing or forcing flue gas recirculation
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23DBURNERS
    • F23D2209/00Safety arrangements
    • F23D2209/20Flame lift-off / stability

Definitions

  • the present invention relates to a burner head according to the features of claim 1.
  • a burner of a combustion system in which the fuel supplied is first injected into a directly adjoining zone via a fuel nozzle.
  • a combustion air duct is arranged concentrically with the fuel nozzle and closes with an orifice on the outflow side.
  • a further combustion air duct is arranged, which closes in the region of the level of the fuel nozzle with swirl-generating means which trigger vortices within the adjoining zone.
  • This zone adjoining the fuel nozzle is of conical design and, distributed over its circumference, it has openings through which an air flow originating from a further concentrically arranged channel flows into the interior, and there partiallyITAd the vortices.
  • this mixture-forming zone On the outflow side of this mixture-forming zone there is a burnout tube which has essentially the same flow cross-section as the outlet cross-section of the mixture-forming zone acting upstream. An annular wave-like flow of the hot gases is formed in the burnout tube itself and moves in the axial direction.
  • the invention is based on the object of minimizing the pollutant emissions, in particular the NOx-CO and UHC emissions, in a burner head of the type mentioned.
  • the main advantage of the invention is that the shape of the burner head and the guiding of the combustion air through the burner result in a stabilization of the flame at the end of a premixing zone in the center and / or on the outer edge of the combustion chamber. If necessary, such flame stabilization can be achieved by introducing an interfering body downstream of the premixing zone.
  • a further advantage of the invention can be seen in the fact that the design of the burner head ensures natural, permanent protection of the fuel lance against caloric effects of the exhaust gas recirculated into the combustion chamber for mixing purposes. This is achieved by placing the fuel lance in a flow channel for the fresh air supply.
  • Another advantage of the invention is that at least a portion of the combustion air, which is preferably fresh air, receives a swirl in the region of its admixture with the exhaust gases introduced ( ⁇ fresh air> ⁇ exhaust gases) in the center of the flow.
  • Another important advantage of the invention results from the simple construction of the burner and its adaptability to the desired operation.
  • the only figure shows the design of a burner head.
  • the figure shows a burner head of an atmospheric furnace, which consists of a fuel lance 1 in the central area, which in turn ends in the direction of flow with a fuel nozzle 2.
  • the fuel nozzle 2 which is shown in the figure and is designed for a liquid fuel, acts downstream of an orifice 3, which forms the end of a first channel 4, through which fresh air 5 is brought in.
  • This fuel nozzle 2 is an atomizing nozzle, which preferably works at pressures between 4 and 30 bar.
  • the configuration shown here between the fuel nozzle 2 and the orifice 3 is not the only feasible one, but it can be easily used as the basis for configurations in which the fuel nozzle 2 is at the same height as the orifice 3, or acts upstream of the latter, or by a combination of two or more orifices with air-assisted atomization are characterized. This essentially depends on the criteria according to which the fresh air 5 is supplied in the fresh air duct 4. A second is concentric with this first fresh air duct 4 Channel 6 is provided, through which fresh air 7 is also brought. Both air streams 5, 7 can originate from a single air stream, which is divided at an appropriate distance upstream of the fuel nozzle 3.
  • the first air stream 5 flows unhindered via the orifice 3 into a premixing zone 8 extending downstream of the fuel nozzle 3, the other air stream 7 flows through the second channel 6, which is arranged concentrically to the first channel 4 and is equipped at the end with a number of guide elements 9, that form a swirl body.
  • the swirled air from this swirl body also flows into the premixing zone 8, wherein it mixes beforehand with an exhaust gas stream 10 recirculated by the injector effect.
  • These exhaust gases 10 flow through a tangential channel 11 into the premix zone 8.
  • the combustion air in the premixing zone 8 is concerned, it can be said that in most cases this will consist of pure fresh air; however, as can be seen from the figure, it can also consist of a mixture of fresh air 7 and recirculated exhaust gas 10. Both the fresh air and the recirculated exhaust gas can also be easily enriched with a portion of a gaseous fuel.
  • the inflowing exhaust gas 10 is introduced into the premixing zone 8 by flow aids 12a, 12b, it initially mixing with the fresh air 7 downstream of the guide elements 9.
  • the continuation of the flow aid 12b in the direction of flow merges into a premixing tube 13, which extends to approximately the level of a vortex backflow zone 14, and there forms an extension 16 to a burnout tube 19 concentric with the latter tube 13, relative to the radial extension of the premixing zone 8.
  • This vortex backflow zone 14, the center 14a of which forms a calm zone ensures that flame stabilization occurs at the end of the premixing zone 8.
  • the spray angle from the fuel nozzle 2 is designed such that the premix pipe 13 is not wetted. A first mixing with the fuel from the nozzle 2 takes place first of all through the fresh air 5 from the channel 4.
  • the figure shows a geometrical variant of the burnout tube at the end of the premixing tube 13:
  • the geometrical shape of this burnout tube characterized by a bulge 19a with a larger cross section, corresponds to the natural spatial shape of the swirl ring 17, which affects the flame stabilization in the combustion chamber 15, which is due to the diameter the burnout tubes 19 and 19a is limited, additionally has a positive effect, since this also prevents the vortex backflow zone 14 from migrating, ie flattening outward, into the premixing zone 8.
  • the flow of the media ie the fresh air 5 relative to the fuel nozzle 2 and the other fresh air 7 and the exhaust gases 10 relative to the orifice 3 and.
  • the premixing zone 8 can be held radially, quasi-radially to axially, depending on how the operating conditions are kept in the combustion chamber 15. As far as the rate of the recirculated exhaust gases 10 is concerned, it must be taken into account that a higher recirculation rate brings about an additional reduction in the O 2 concentration in the combustion air, and thus a lower flame temperature in the combustion chamber, so that the NOx emissions can be minimized. If the flame without guide elements 9, that is, without swirl, and without extension 16, that is, without a jump in diameter between premixing tube 13 and burnout tube 19, respectively. 19a, are stabilized, then after the premixing zone 8 there is a disturbing body 20 which can have different geometrical configurations. In principle, a central physical thickening is sufficient for such a disturbing body 20, as is shown in the figure.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Spray-Type Burners (AREA)

Abstract

The burner head has a fuel lance (1) which runs through the burner head in its length and which ends on the downstream side with a fuel nozzle (2). Acting around this fuel lance (1) is a combustion air duct (4) which stops on the downstream side with a screen (3). Arranged around this first combustion air duct (4) is a further combustion air duct (6) which passes on the downstream side into an outlet, where a number of guide members (9) is situated, which impose a twist on at least the combustion air flowing through this duct. Also affected by this twist are the waste gases (10) flowing in through a tangential duct (11) in the region of the guide members (9), as a result of which there is good mixing between the two media. Acting on the downstream side of the fuel nozzle (2) is a premixing zone (8), adjoining the end of which is a vortex backflow zone (14), As far as this vortex backflow zone, the combustion chamber is provided with a premixing pipe (13), and subsequently a combustion pipe (19, 19a) acts, which has a greater cross-section in relation to the premixing pipe (13). At the transition of these two pipes, a vortex ring (17) is formed, which surrounds the vortex backflow zone (14) and ensures that the flame stabilisation is maintained, by the last-mentioned zone not being able to flatten. The initial ignition (18) of the mixture takes place in the vortex ring (17).

Description

Technisches GebietTechnical field

Die vorliegende Erfindung betrifft einen Brennerkopf gemäss den Merkmalen des Anspruchs 1.The present invention relates to a burner head according to the features of claim 1.

Stand der TechnikState of the art

Bei Brennerdispositiven mit einer Vormischstrecke und einer freien Mündung zum in Abströmungsrichtung nachgeschalteten Brennraum stellt sich immer wieder das Problem , wie auf einfachste Art und Weise eine stabile Flamme erstellt werden kann. Hierüber sind bereits verschiedene Vorschläge bekanntgeworden, die an sich nicht zu befriedigen vermochten. Eine bis anhin bekanntgewordene Ausnahme bildet der Erfindungsgegenstand gemäss EP-A1-321 809, der wohl gegenüber dem Stand der Technik sowohl betreffend Minimierung der Schadstoff-Emissionen als auch bezüglich Wirkungsgrades einen Quantensprung darstellt. Es gibt indessen Spezialfälle bei atmosphärischen Feuerungsanlagen, bei welchen der obengenannte Erfindungsgegenstand aus anderen Motiven nicht zum Einsatz gebracht werden kann, womit diese Feuerungsanlagen, gezwungenermassen, nach wie vor mit einer überholten Technik betrieben werden müssten, was schon im Lichte der gesetzlich maximal zulässigen Schadstoff-Emissionen nicht mehr zulässig ist.In burner dispensers with a premixing section and a free mouth to the combustion chamber downstream in the outflow direction, there is always the problem of how to create a stable flame in the simplest way. Various proposals have already become known about this, which in themselves were unsatisfactory. An exception that has become known so far is the subject of the invention according to EP-A1-321 809, which is a quantum leap compared to the prior art both in terms of minimizing pollutant emissions and in terms of efficiency. There are, however, special cases in atmospheric combustion plants in which the above-mentioned subject matter of the invention cannot be used for other reasons, with which these combustion plants are still forced to operate with an outdated technology would have to be what is no longer permitted in the light of the legally permissible maximum pollutant emissions.

Aus US-A-4,431,403 ist ein Brenner einer Feuerungsanlage bekanntgeworden, bei welchem der herangeführte Brennstoff über eine Brennstoffdüse zunächst in eine unmittelbar anschliessende Zone eingedüst wird. Konzentrisch zu der Brennstoffdüse ist ein Verbrennungsluftkanal angeordnet, der abströmungsseitig mit einer Blende abschliesst. Wiederum konzentrisch zu diesem ersten Verbrennungsluftkanal ist ein weiterer Verbrennungsluftkanal angeordnet, der im Bereich der Ebene der Brennstoffdüse mit drallerzeugenden Mitteln abschliesst, welche innerhalb der anschliessenden Zone Wirbel auslösen. Diese sich der Brennstoffdüse anschliessende Zone ist von konischer Ausgestaltung und sie weist, über ihren Umfang verteilt, Oeffnungen auf, durch welche ein von einem weiteren konzentrisch angeordneten Kanal stammender Luftstrom in den Innenraum strömt, und dort teilweise die Wirbel alimentiert. Abströmungsseitig dieser gemischbildenden Zone schliesst sich ein Ausbrandrohr an, welches im wesentlichen den gleichen Durchflussquerschnitt wie der Ausgangsquerschnitt der stromauf wirkenden gemischbildenden Zone aufweist. Im Ausbrandrohr selbst bildet sich eine ringförmige wellenartige Strömung der Heissgase, welche sich in axialer Richtung fortbewegt.From US-A-4,431,403 a burner of a combustion system has become known, in which the fuel supplied is first injected into a directly adjoining zone via a fuel nozzle. A combustion air duct is arranged concentrically with the fuel nozzle and closes with an orifice on the outflow side. Again, concentrically to this first combustion air duct, a further combustion air duct is arranged, which closes in the region of the level of the fuel nozzle with swirl-generating means which trigger vortices within the adjoining zone. This zone adjoining the fuel nozzle is of conical design and, distributed over its circumference, it has openings through which an air flow originating from a further concentrically arranged channel flows into the interior, and there partially alimented the vortices. On the outflow side of this mixture-forming zone there is a burnout tube which has essentially the same flow cross-section as the outlet cross-section of the mixture-forming zone acting upstream. An annular wave-like flow of the hot gases is formed in the burnout tube itself and moves in the axial direction.

Darstellung der ErfindungPresentation of the invention

Der Erfindung, wie sie in Anspruch 1 gekennzeichnet ist, liegt die Aufgabe zugrunde, bei einem Brennerkopf der eingangs genannten Art die Schadstoff-Emissionen, insbesondere die NOx-CO- und UHC-Emissionen, zu minimieren.The invention, as characterized in claim 1, is based on the object of minimizing the pollutant emissions, in particular the NOx-CO and UHC emissions, in a burner head of the type mentioned.

Der wesentliche Vorteil der Erfindung ist darin zu sehen, dass durch die Formgebung des Brennerkopfes sowie die Führung der Verbrennungsluft durch den Brenner sich am Ende einer Vormischzone im Zentrum und/oder am Aussenrand des Brennraumes eine Stabilisation der Flamme einstellt. Bei Bedarf kann eine solche Flammenstabilisation durch Einbringen eines Störkörpers stromab der Vormischzone erreicht werden.The main advantage of the invention is that the shape of the burner head and the guiding of the combustion air through the burner result in a stabilization of the flame at the end of a premixing zone in the center and / or on the outer edge of the combustion chamber. If necessary, such flame stabilization can be achieved by introducing an interfering body downstream of the premixing zone.

Ein weiterer Vorteil der Erfindung ist darin zu sehen, dass die Ausgestaltung des Brennerkopfes einen natürlichen dauernden Schutz der Brennstofflanze vor kalorischen Einwirkungen des zu Mischzwecken in den Brennraum rezirkulierten Abgases gewährleistet. Dies wird erreicht, indem die Brennstofflanze in einem Strömungskanal für die Frischluftzuführung plaziert ist.A further advantage of the invention can be seen in the fact that the design of the burner head ensures natural, permanent protection of the fuel lance against caloric effects of the exhaust gas recirculated into the combustion chamber for mixing purposes. This is achieved by placing the fuel lance in a flow channel for the fresh air supply.

Ein weiterer Vorteil der Erfindung ist darin zu sehen, dass mindestens ein Teil der Verbrennungsluft, die vorzugsweise Frischluft ist, im Bereich ihrer Zumischung mit den herangeführten Abgasen einen Drall (ρ Frischluft > ρ Abgase) im Zentrum der Strömung erhält.Another advantage of the invention is that at least a portion of the combustion air, which is preferably fresh air, receives a swirl in the region of its admixture with the exhaust gases introduced (ρ fresh air> ρ exhaust gases) in the center of the flow.

Ein weiterer wesentlicher Vorteil der Erfindung ergibt sich aus der einfachen Konstruktion des Brenners, und dessen Anpassungsfähigkeit nach dem jeweils gewünschten Betrieb.Another important advantage of the invention results from the simple construction of the burner and its adaptability to the desired operation.

Vorteilhafte und zweckmässige Weiterbildungen der erfindungsgemässen Aufgabenlösung sind in den weiteren Ansprüchen gekennzeichnet.Advantageous and expedient developments of the task solution according to the invention are characterized in the further claims.

Im folgenden wird anhand der einzigen Figur ein Ausführungsbeispiel der Erfindung dargestellt und näher erläutert. Alle für das unmittelbare Verständnis der Erfindung nicht erforderlichen Elemente sind fortgelassen. Die Strömungsrichtung der Medien ist mit Pfeilen angegeben.An exemplary embodiment of the invention is illustrated and explained in more detail below with reference to the single figure. All elements not necessary for the immediate understanding of the invention have been omitted. The direction of flow of the media is indicated by arrows.

Kurze Darstellung der ZeichnungBrief presentation of the drawing

Die einzige Figur zeigt die Ausgestaltung eines Brennerkopfes.The only figure shows the design of a burner head.

Wege zur Ausführung der Erfindung und gewerbliche VerwertbarkeitWays of carrying out the invention and commercial usability

Die Figur zeigt einen Brennerkopf einer atmosphärischen Feuerungsanlage, der im zentralen Bereich aus einer Brennstofflanze 1 besteht, welche ihrerseits in Strömungsrichtung mit einer Brennstoffdüse 2 endet. Die in der Figur ersichtliche für einen flüssigen Brennstoff ausgelegte Brennstoffdüse 2 wirkt stromab einer Blende 3, welche den Abschluss eines ersten Kanals 4 bildet, durch welchen Frischluft 5 herangeführt wird. Bei dieser Brennstoffdüse 2 handelt es sich um eine Zerstäubungsdüse, welche vorzugsweise mit Drücken zwischen 4 und 30 bar arbeitet. Die hier gezeigte Konfiguration zwischen Brennstoffdüse 2 und Blende 3 ist nicht die einzige machbare, sondern es können ohne weiteres Konfigurationen zugrundegelegt werden, bei welchen sich die Brennstoffdüse 2 auf gleicher Höhe der Blende 3 befindet, oder stromauf der letztgenannten wirkt, oder durch eine Kombination von zwei oder mehreren Blenden mit luftunterstützten Zerstäubung charakterisiert sind. Dies hängt im wesentlichen davon ab, nach welchen Kriterien die Frischluft 5 im Frischluftkanal 4 zugeführt wird. Konzentrisch zu diesem ersten Frischluftkanal 4 ist ein zweiter Kanal 6 vorgesehen, durch welchen ebenfalls Frischluft 7 herangeführt wird. Beide Luftströme 5, 7 können aus einem einzigen Luftstrom stammen, welcher sich in einem angemessenen Abstand stromauf der Brennstoffdüse 3 aufteilt. Während der erste Luftstrom 5 unbehindert über die Blende 3 in eine stromab der Brennstoffdüse 3 sich erstreckende Vormischzone 8 einströmt, strömt der andere Luftstrom 7 durch den konzentrisch zum ersten Kanal 4 angelegten zweiten Kanal 6, der endseitig mit einer Reihe von Leitorganen 9 bestückt ist, die einen Drallkörper bilden. Die verdrallte Luft aus diesen Drallkörper strömt ebenfall in die Vormischzone 8 ein, wobei sie sich vorgängig mit einem durch Injektorwirkung rezirkulierten Abgasstrom 10 vermischt. Diese Abgase 10 strömen durch einen tangentialen Kanal 11 in die Vormischzone 8 ein. Was die Verbrennungsluft in der Vormischzone 8 betrifft, so ist zu sagen, dass diese in den meisten Fällen aus reiner Frischluft bestehen wird; sie kann aber auch, wie dies aus der Figur hervorgeht, aus einem Gemisch aus Frischluft 7 und rückgeführtem Abgas 10 bestehen. Sowohl die Frischluft als auch das rückgeführte Abgas können darüber hinaus ohne weiteres mit einem Anteil eines gasförmigen Brennstoffes angereichert werden. Das einströmende Abgas 10 wird durch Strömungshilfen 12a, 12b in die Vormischzone 8 eingeleitet, wobei es sich stromab der Leitorgane 9 vorerst mit der Frischluft 7 vermischt. Die Fortsetzung der Strömungshilfe 12b in Strömungsrichtung geht in ein Vormischrohr 13 über, das sich bis etwa auf Höhe einer Wirbelrückströmzone 14 erstreckt, und dort gegenüber der radialen Ausdehnung des Vormischzone 8 eine Erweiterung 16 zu einem zu letztgenanntem Rohr 13 konzentrischen Ausbrandrohr 19 bildet. Diese Wirbelrückströmzone 14, deren Zentrum 14a eine ruhige Zone bildet, sorgt dafür, dass sich am Ende der Vormischzone 8 eine Flammenstabilisierung einstellt. Der Sprühwinkel aus der Brennstoffdüse 2 ist so ausgelegt, dass das Vormischrohr 13 nicht benetzt wird. Eine erste Vermischung mit dem Brennstoff aus der Düse 2 geschieht zunächst durch die Frischluft 5 aus dem Kanal 4. Im allgemeinen ist zu erwarten, dass sich diese Vermischung etwa entsprechend dem Sprühwinkel aus der Brennstoffdüse 2 ausbreiten wird, so dass das Gemisch aus Frischluft 7 und Abgas 10, das mit einem Drall in die Vormischzone 8 einströmt, erst am Ende des Vormischrohres 13 zur Zündung gelangt. Hinter der Erweiterung 16 entsteht ein räumlich begrenzter Wirbelring 17, welcher die Flammenstabilisierung unterstützt, denn damit kann sich die Wirbelrückströmzone 14 nicht gegen aussen verflachen, wohin sie tendentiell neigt. An der stromabwärtsseitigen Peripherie dieses Wirbelringes 17 ist ein Ort 18 vorgesehen, wo die Initialzündung des Brennstoff/Verbrennungsluft-Gemisches stattfindet. In der Figur ist eine geometrische Variante des Ausbrandrohres am Ende des Vormischrohres 13 ersichtlich: Die geometrische Formgebung dieses Ausbrandrohres, durch eine querschnittsvergrössernde Ausbuchtung 19a charakterisiert, entspricht der natürlichen räumlichen Form des Wirbelringes 17, was sich auf die Flammenstabilisierung im Brennraum 15, der durchmesserseitig durch die Ausbrandrohre 19 und 19a begrenzt ist, zusätzlich positiv auswirkt, denn damit wird auch eine Wanderung der Wirbelrückströmzone 14, d.h. eine Verflachung derselben nach aussen, in die Vormischzone 8 verhindert. Die Strömung der Medien, also der Frischluft 5 gegenüber der Brennstoffdüse 2 und der anderen Frischluft 7 sowie der Abgase 10 gegenüber der Blende 3 resp. der Vormischzone 8 kann radial, quasi-radial bis axial gehalten werden, je nach dem, wie die Betriebsverhältnisse im Brennraum 15 gehalten werden. Was die Rate der rückgeführten Abgase 10 betrifft, so ist zu berücksichtigen, dass eine höhere Rezirkulationsrate eine zusätzliche Reduktion der O2-Konzentration in der Verbrennungsluft bewirkt, und damit eine tiefere Flammentemperatur im Brennraum, damit können die NOx-Emissionen minimiert werden. Soll die Flamme ohne Leitorgane 9, also ohne Drall, und ohne Erweiterung 16 , also ohne Durchmessersprung zwischen Vormischrohr 13 und Ausbrandrohr 19 resp. 19a, stabilisiert werden, so sieht man nach der Vormischzone 8 einen Störkörper 20 vor, der verschiedene geometrische Ausgestaltungen haben kann. Grundsätzlich genügt für einen solchen Störkörper 20 eine zentrale körperliche Verdickung, wie dies in der Figur versinnbildlicht wird.The figure shows a burner head of an atmospheric furnace, which consists of a fuel lance 1 in the central area, which in turn ends in the direction of flow with a fuel nozzle 2. The fuel nozzle 2, which is shown in the figure and is designed for a liquid fuel, acts downstream of an orifice 3, which forms the end of a first channel 4, through which fresh air 5 is brought in. This fuel nozzle 2 is an atomizing nozzle, which preferably works at pressures between 4 and 30 bar. The configuration shown here between the fuel nozzle 2 and the orifice 3 is not the only feasible one, but it can be easily used as the basis for configurations in which the fuel nozzle 2 is at the same height as the orifice 3, or acts upstream of the latter, or by a combination of two or more orifices with air-assisted atomization are characterized. This essentially depends on the criteria according to which the fresh air 5 is supplied in the fresh air duct 4. A second is concentric with this first fresh air duct 4 Channel 6 is provided, through which fresh air 7 is also brought. Both air streams 5, 7 can originate from a single air stream, which is divided at an appropriate distance upstream of the fuel nozzle 3. While the first air stream 5 flows unhindered via the orifice 3 into a premixing zone 8 extending downstream of the fuel nozzle 3, the other air stream 7 flows through the second channel 6, which is arranged concentrically to the first channel 4 and is equipped at the end with a number of guide elements 9, that form a swirl body. The swirled air from this swirl body also flows into the premixing zone 8, wherein it mixes beforehand with an exhaust gas stream 10 recirculated by the injector effect. These exhaust gases 10 flow through a tangential channel 11 into the premix zone 8. As far as the combustion air in the premixing zone 8 is concerned, it can be said that in most cases this will consist of pure fresh air; however, as can be seen from the figure, it can also consist of a mixture of fresh air 7 and recirculated exhaust gas 10. Both the fresh air and the recirculated exhaust gas can also be easily enriched with a portion of a gaseous fuel. The inflowing exhaust gas 10 is introduced into the premixing zone 8 by flow aids 12a, 12b, it initially mixing with the fresh air 7 downstream of the guide elements 9. The continuation of the flow aid 12b in the direction of flow merges into a premixing tube 13, which extends to approximately the level of a vortex backflow zone 14, and there forms an extension 16 to a burnout tube 19 concentric with the latter tube 13, relative to the radial extension of the premixing zone 8. This vortex backflow zone 14, the center 14a of which forms a calm zone, ensures that flame stabilization occurs at the end of the premixing zone 8. The spray angle from the fuel nozzle 2 is designed such that the premix pipe 13 is not wetted. A first mixing with the fuel from the nozzle 2 takes place first of all through the fresh air 5 from the channel 4. In general, it is to be expected that this mixing will spread out from the fuel nozzle 2 approximately according to the spray angle, so that the mixture spreads out Fresh air 7 and exhaust gas 10, which flows into the premixing zone 8 with a swirl, only come to ignition at the end of the premixing tube 13. Behind the extension 16 there is a spatially limited vortex ring 17 which supports the flame stabilization, because the vortex backflow zone 14 cannot flatten outwards wherever it tends to. At the downstream periphery of this swirl ring 17, a location 18 is provided where the initial ignition of the fuel / combustion air mixture takes place. The figure shows a geometrical variant of the burnout tube at the end of the premixing tube 13: The geometrical shape of this burnout tube, characterized by a bulge 19a with a larger cross section, corresponds to the natural spatial shape of the swirl ring 17, which affects the flame stabilization in the combustion chamber 15, which is due to the diameter the burnout tubes 19 and 19a is limited, additionally has a positive effect, since this also prevents the vortex backflow zone 14 from migrating, ie flattening outward, into the premixing zone 8. The flow of the media, ie the fresh air 5 relative to the fuel nozzle 2 and the other fresh air 7 and the exhaust gases 10 relative to the orifice 3 and. The premixing zone 8 can be held radially, quasi-radially to axially, depending on how the operating conditions are kept in the combustion chamber 15. As far as the rate of the recirculated exhaust gases 10 is concerned, it must be taken into account that a higher recirculation rate brings about an additional reduction in the O 2 concentration in the combustion air, and thus a lower flame temperature in the combustion chamber, so that the NOx emissions can be minimized. If the flame without guide elements 9, that is, without swirl, and without extension 16, that is, without a jump in diameter between premixing tube 13 and burnout tube 19, respectively. 19a, are stabilized, then after the premixing zone 8 there is a disturbing body 20 which can have different geometrical configurations. In principle, a central physical thickening is sufficient for such a disturbing body 20, as is shown in the figure.

BezeichnungslisteLabel list

11
BrennstofflanzeFuel lance
22nd
BrennstoffdüseFuel nozzle
33rd
Blendecover
44th
VerbrennungsluftkanalCombustion air duct
55
VerbrennungsluftCombustion air
66
VerbrennungsluftkanalCombustion air duct
77
VerbrennungsluftCombustion air
88th
VormischzonePremixing zone
99
LeitorganeGoverning bodies
1010th
AbgaseExhaust gases
1111
Tangentialer KanalTangential channel
12a12a
StrömungshilfenFlow aids
12b12b
StrömungshilfenFlow aids
1313
VormischrohrPremix pipe
1414
WirbelrückströmzoneVortex backflow zone
14a14a
Zentrum der WirbelrückströmzoneCenter of the vortex backflow zone
1515
BrennraumCombustion chamber
1616
Erweiterungextension
1717th
WirbelringSwirl ring
1818th
Ort der InitialzündungPlace of initial ignition
1919th
AusbrandrohrBurnout pipe
19a19a
AusbrandrohrBurnout pipe
2020th
StörkörperDisruptive body

Claims (5)

  1. Burner head for the premix-like combustion of a liquid fuel in an atmospheric system, the burner head having a fuel lance with a fuel nozzle, around which is arranged a combustion-air duct which is terminated on the outflow side by at least one diaphragm, there being arranged around this combustion-air duct at least one further combustion-air duct which is provided on the outflow side with a number of guide members, and there being located on the outflow side of the fuel nozzle a combustion space which consists, in the outflow direction, of a premixing tube and of a burn-out tube, the burn-out tube (19, 19a) having, as a result of a step-shaped radial widening (16), a larger cross-section than the preceding premixing tube (13), and in that the premixing tube (13) is flow-free in the radial direction and the widening (16) is flow-free in the axial direction.
  2. Burner head according to Claim 1, characterized in that the further combustion-air duct (11) opens into the combustion space (15) upstream of the premixing tube (13).
  3. Burner head according to Claim 1, characterized in that the premixing tube (13) and the burn-out tube (19, 19a) are concentric to one another.
  4. Burner head according to Claim 3, characterized in that the premixing tube (13) and the burn-out tube (19) are cylindrical.
  5. Burner head according to Claim 1, characterized in that the diaphragm (3) is placed upstream of, level with or downstream of the fuel nozzle (3).
EP90124798A 1990-12-19 1990-12-19 Burner head for premix combustion of a liquid fuel in an atmospheric combustion installation Expired - Lifetime EP0491079B1 (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
EP90124798A EP0491079B1 (en) 1990-12-19 1990-12-19 Burner head for premix combustion of a liquid fuel in an atmospheric combustion installation
DE59010544T DE59010544D1 (en) 1990-12-19 1990-12-19 Burner head for the premixed combustion of a liquid fuel in an atmospheric furnace
AT90124798T ATE144316T1 (en) 1990-12-19 1990-12-19 BURNER HEAD FOR THE PREMIXED COMBUSTION OF A LIQUID FUEL IN AN ATMOSPHERIC FIREPLACE

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP90124798A EP0491079B1 (en) 1990-12-19 1990-12-19 Burner head for premix combustion of a liquid fuel in an atmospheric combustion installation

Publications (2)

Publication Number Publication Date
EP0491079A1 EP0491079A1 (en) 1992-06-24
EP0491079B1 true EP0491079B1 (en) 1996-10-16

Family

ID=8204866

Family Applications (1)

Application Number Title Priority Date Filing Date
EP90124798A Expired - Lifetime EP0491079B1 (en) 1990-12-19 1990-12-19 Burner head for premix combustion of a liquid fuel in an atmospheric combustion installation

Country Status (3)

Country Link
EP (1) EP0491079B1 (en)
AT (1) ATE144316T1 (en)
DE (1) DE59010544D1 (en)

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19606733C1 (en) * 1996-02-23 1997-05-07 Viessmann Werke Kg Oil evaporation burner operating process
DE19704721B4 (en) * 1997-02-07 2006-08-17 E.C.B. Gmbh Process and combustion head for the combustion of liquid or gaseous fuels
DE19814768A1 (en) * 1998-04-02 1999-10-07 Viessmann Werke Kg Blue burner
BRPI0413966A (en) * 2003-09-05 2006-10-31 Delavan Inc burner for a gas turbine combustor
JP4955117B1 (en) * 2011-03-15 2012-06-20 新日鉄エンジニアリング株式会社 Top-fired hot air furnace
JP4892107B1 (en) 2011-03-23 2012-03-07 新日鉄エンジニアリング株式会社 Top-fired hot air furnace

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1501868B2 (en) * 1966-02-21 1973-02-22 Linde, Robert von, Dipl Ing , 8032 Grafelfing BURNERS FOR FLOWABLE FUELS
BE795261A (en) * 1972-02-10 1973-05-29 Bailey Frank W BLUE FLAME RETENTION CANNON BURNERS AND HEAT EXCHANGER SYSTEMS
US4431403A (en) * 1981-04-23 1984-02-14 Hauck Manufacturing Company Burner and method
CH674561A5 (en) * 1987-12-21 1990-06-15 Bbc Brown Boveri & Cie

Also Published As

Publication number Publication date
DE59010544D1 (en) 1996-11-21
EP0491079A1 (en) 1992-06-24
ATE144316T1 (en) 1996-11-15

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