EP0780630B1 - Burner for a heat generator - Google Patents

Description

Technical field

The present invention relates to a burner according to the preamble of claim 1.

State of the art

a) Es findet eine nicht zu unterschätzende Erhöhung der Gefahr eines Flammenrückschlages statt, wobei dies leicht zu einem Abbrennen von Teilen des Vormischbrenners führen kann. Findet eine solche statt, so entsteht ein Gefahrenpotential, insoweit, als abbröckelnde Teile eine schwerwiegende Havarie der Maschine auslösen können;

b) Ein Betrieb bei optimaler Flammenposition mit einem Flüssigbrennstoff darf aus Sicherheitsgründen nicht breit ausgelegt sein, womit der Vormischbrenner einen kleinen Betriebsbereich aufweist;

c) Das Fehlen einer integralen Durchmischung von Anbeginn zwischen dem Spraykegel und dem Verbrennungsluftstrom aus obengenannten Gründen führt unweigerlich zu einer Steigerung der NOx-Emissionen;

d) Die inhomogene Gemischverteilung führt darüber hinaus zu weiteren Nachteilen, welche erhöhte Schadstoff-Emissionen sowie die Entstehung von Pulsationen auslösen;

e) Von den optimalen Strömungsbedingungen für eine sichere und effiziente Verbrennung sind grosse Abweichungen auszumachen.

If, in the case of swirl-stabilized burners, such as a premix burner, for example from EP-B1-0 321 809, a liquid fuel is injected on the burner axis, the liquid column which forms downstream from the fuel nozzle has a particular effect on the combustion air flow flowing tangentially into the interior of the premix burner like a solid in the first area downstream of the injection. Compared to the flow without liquid fuel injection, the inflow of combustion air in the burner head is impeded, which increases the tangential component of the swirl flow that forms. This leads to a change in the flame position, which moves further upstream. If a further injection of fuel is carried out along the tangential air inlet slots, the operation of such a fuel injection is extremely at risk because a flame front acting in this area inevitably leads to a re-ignition into the system. Furthermore, the flame center is enriched, which manifoldly disadvantages the operation of such a premix burner. In such an operation, various disadvantages can be identified, which, if not exhaustively listed, can be recorded as follows:

a) There is an increase in the risk of flashback, which should not be underestimated, and this can easily lead to parts of the premix burner burning off. If this takes place, there is a potential hazard, insofar as crumbling parts can cause a serious damage to the machine;

b) For safety reasons, operation with an optimal flame position with a liquid fuel must not be broadly designed, which means that the premix burner has a small operating range;

c) The lack of an integral mixing from the beginning between the spray cone and the combustion air flow for the reasons mentioned above inevitably leads to an increase in NOx emissions;

d) The inhomogeneous mixture distribution also leads to further disadvantages, which trigger increased pollutant emissions and the development of pulsations;

e) There are large deviations from the optimal flow conditions for safe and efficient combustion.

A swirl-stabilized burner is known from JP 07 190 308, in which a mixing tube is connected downstream of the swirl generator. However, it can be easily assumed that very similar properties are inherent here, particularly with regard to the flame retardation problem.

Presentation of the invention

The invention seeks to remedy this. The invention how it is marked in the claims, the task lies the basis for a premix burner of the type mentioned Kind of a flame stabilization with maximized efficiency and to minimize pollutant emissions.

The essential measure of the invention relates to the position the head-side fuel nozzle, which by a certain Distance upstream from the inflow of combustion air is reset, this distance from the selected Spray angle depends. With this transfer comes Mouth of the fuel nozzle in the area of a solid casing to stand, which means at the same time radially around the nozzle mouth Openings can be provided through which Purge air in the cross section induced by the fuel nozzle flows in. The flow cross section of these openings is selected so that in gas operation through these openings flowing air mass flow is not sufficient to the To move the backflow zone further downstream. In liquid fuel mode the fuel spray acts practically as a jet pump, with which the air mass flow through the named Openings increased. This causes a larger axial momentum which moves the backflow zone further downstream.

Another advantage of the invention is that by the reset of the fuel nozzle with the fuel spray a larger cone radius in the main flow, i.e. in the Combustion air flowing through the tangential air inlet slots entry. The fuel spray is in this Layer already decayed from a film into drops and the conical surface this fuel spray has entered into the area of the combustion air from the tangential Air inlet slots enlarged by a factor of 3. Thereby the spread of the fuel spray is improved and the Combustion air inflow not impeded.

Finally, it should be noted that through the openings Air mass flow sucked in in the area of the fuel nozzle prevents wetting of the inside of the cone because it lays out as a film between the fuel spray and the wall everything defines the opening angle of the spray. This remains constant over a wide load range.

Another important advantage of the invention is that see that by varying the opening cross sections for the Air mass flow in the area of the fuel nozzle the return flow zone and thus the flame position directly during operation can be influenced.

Advantageous and expedient developments of the inventive Task solutions are characterized in the other claims.

In the following, exemplary embodiments will be described with reference to the drawings the invention explained in more detail. All for immediate understanding are not necessary elements of the invention been left out. The same elements are in the different Figures with the same reference numerals. The The direction of flow of the media is indicated by arrows.

Brief description of the drawings

Fig. 1

einen als Vormischbrenner ausgelegten Brenner mit einer Mischstrecke stromab eines Drallerzeugers,

Fig. 2

eine schematische Darstellung des Drallerzeugers mit Positionierung der Brennstoffeindüsung,

Fig. 3

einen Drallerzeuger als Bestandteil des Vormischbrenners nach Fig. 1, in perspektivischer Darstellung, entsprechend aufgeschnitten,

Fig. 4

eine Schnittebene durch den als zweischalig ausgebildeten Drallerzeuger nach Fig. 3,

Fig. 5

eine Schnittebene durch einen vierschaligen Drallerzeuger,

Fig. 6

eine Schnittebene durch einen Drallerzeuger, dessen Schalen schaufelförmig profiliert sind,

Fig. 7

eine Darstellung der Form der Uebergangsgeometrie zwischen Drallerzeuger und nachgeschalteter Mischstrecke und

Fig. 8

eine Abrisskante zur räumlichen Stabilisierung der Rückströmzone.

It shows:

Fig. 1

a burner designed as a premix burner with a mixing section downstream of a swirl generator,

Fig. 2

1 shows a schematic representation of the swirl generator with the fuel injection positioned,

Fig. 3

1, a swirl generator as part of the premix burner according to FIG. 1, in a perspective view, correspondingly cut open,

Fig. 4

4 shows a sectional plane through the swirl generator designed as a double-shell according to FIG. 3,

Fig. 5

a cutting plane through a four-shell swirl generator,

Fig. 6

a cutting plane through a swirl generator, the shells of which are profiled in the shape of a blade

Fig. 7

a representation of the shape of the transition geometry between the swirl generator and the downstream mixing section and

Fig. 8

a tear-off edge for spatial stabilization of the backflow zone.

WAYS OF CARRYING OUT THE INVENTION, INDUSTRIAL APPLICABILITY

Fig. 1 shows the overall structure of a burner. Is initially a swirl generator 100a effective, the design of which in the following Fig. 2-5 shown and described in more detail becomes. This swirl generator 100a is a conical structure, the tangential multiple of a tangential inflowing combustion air flow 115 is applied becomes. The flow that forms here is based on a transition geometry provided downstream of the swirl generator 100a transitioned seamlessly into a transition piece 200, in such a way that no detachment areas occur there can. The configuration of this transition geometry is under Fig. 6 described in more detail. This transition piece is 200 downstream of the transition geometry through a pipe 20 extended, both parts of the actual mixing tube 220, also called mixing section, form the burner. Of course the mixing tube 220 may consist of a single piece, i.e. then that the transition piece 200 and pipe 20 merged into a single coherent structure with the characteristics of each part preserved stay. Become transition piece 200 and tube 20 from two parts created, they are connected by a socket ring 10, the same bushing ring 10 on the head side as the anchoring surface serves for the swirl generator 100a. Such a Socket ring 10 also has the advantage that different Mixing tubes can be used. Outflow side of the tube 20 is the actual combustion chamber 30, which only symbolizes here through the flame tube is. The mixing tube 220 meets the condition that downstream of the swirl generator 100a provided a defined mixing section in which a perfect premix of Different types of fuel is achieved. This mixing section, so the mixing tube 220, further enables one lossless flow control, so that even in operative connection initially no backflow zone with the transition geometry can form, thus over the length of the mixing tube 220 influence on the quality of the mixture for all types of fuel can be. This mixing tube 220 has another other property, which is that in the mixing tube 220 even the axial speed profile is a pronounced one Possesses maximum on the axis, so that a reignition of the Flame from the combustion chamber is not possible. However it is correct that with such a configuration this axial speed drops to the wall. To reignite also in To prevent this area, the mixing tube 220 in Flow and circumferential direction with a number regularly or irregularly distributed holes 21 of the most varied Provide cross sections and directions through which an amount of air flows into the interior of the mixing tube 220, and along the wall in the sense of a filming an increase in speed induce. Another way the same To achieve effect is that the flow cross section of the mixing tube 220 on the outflow side of the transition channels 201, which has the transition geometry already mentioned form, narrowing, causing the whole Speed level increased within the mixing tube 220 becomes. In the figure, these bores 21 run under one acute angle with respect to the burner axis 60. Furthermore the outlet of the transition channels 201 corresponds to the narrowest Flow cross section of the mixing tube 220. The above Transition channels 201 therefore bridge the respective cross-sectional difference, without making the flow negative to influence. If the precaution chosen by the Guiding the pipe flow 40 along the mixing pipe 220 triggers intolerable pressure loss, can counter this Remedial action can be taken by placing one at the end of the mixing tube Diffuser not shown in the figure is provided. At the A combustion chamber 30 closes at the end of the mixing tube 220 , with a between the two flow cross-sections Cross-sectional jump is present. Only here does one form central backflow zone 50, which has the properties of a Has flame holder. Forms within this cross-sectional jump a flow during operation Edge zone, in which by the prevailing negative pressure Vertebral detachments occur, so this leads to an increased Ring stabilization of the backflow zone 50 the combustion chamber 30 has a number of openings 31 through it which an amount of air directly into the cross-sectional jump streams, and there lower others help that Ring stabilization of the backflow zone 50 is strengthened. Besides It should not go unmentioned that the generation of a stable Backflow zone 50 also has a sufficiently high swirl number in a pipe requires. If this is initially undesirable, so stable return flow zones can be made smaller by the supply strongly swirled air flows at the pipe end, for example through tangential openings. Here you go here assume that the amount of air required for this is approximately 5-20% of the total air volume. As for the design of the Tear edge at the end of the mixing tube 220 is concerned the description referenced in FIG. 8.

Fig. 2 shows a schematic representation of a swirl generator 100a, which is described in more detail in the following FIGS. 3-5 becomes. 1 is the representation of the center placed fuel nozzle 103, which is opposite the beginning 125 of the conical flow cross section set back upstream is, distance 126 from the selected spray angle 105 depends. The mouth 104 comes through this displacement the fuel nozzle 103 in the area of the head-side fixed casing 101a, 102a. That through the relocation of the fuel nozzle 103 arising fuel spray 105 occurs with a larger cone radius in that of the main flow of the combustion air in the interior 114 of the burner Area so that the fuel spray 105 in this area no more than a solid compact body behaves, but has already crumbled into drops and therefore is easy to penetrate. The inflow of combustion air 115 in the fuel spray 105 is no longer hindered what is reflected in the mix quality in a positive sense, in that the fuel spray 105 passes through more easily the combustion air can be penetrated. Furthermore, in the area of the level of the fuel spray orifice 104 radially or quasi-radially arranged openings 124 are provided, through which a purge air in the size of the Inflows cross section induced fuel nozzle 103. The Flow cross-section of these openings 124 is selected so that in gas operation of those flowing through these openings Air mass flow is not sufficient to the backflow zone (cf. Fig. 1) to move further downstream. In liquid fuel mode the fuel spray 105 acts practically as a jet pump, with which the air mass flow through the named Openings 124 increased. This causes a larger axial Impulse that shifts the backflow zone further downstream what acts as a good measure to prevent the flame from reigniting. On the schematically shown conical partial body 101, 102 is discussed in greater detail in FIGS. 2-5. There too Configuration and mode of operation of the tangential air inlet slots 119, 120 discussed in more detail.

In order to better understand the structure of the swirl generator 100a, it is advantageous if at least at the same time as FIG. 2 Fig. 3 is used. Furthermore, around this Fig. 2 not to make it unnecessarily confusing are the after the baffles 121a, 121b shown schematically in FIG. 3 only have been hinted at. In the following, the Description of Fig. 2 as required on the figures mentioned pointed out.

The first part of the burner according to FIG. 1 forms the one according to FIG. 2 shown swirl generator 100a. This consists of two hollows conical partial bodies 101, 102 which are offset from one another are nested. The number of conical Partial body can of course be larger than two, such as Figures 4 and 5 show; this depends on how each further will be explained in more detail below, depending on the type of debt collection of the whole burner. It is with certain operating constellations not excluded one from one single spiral existing swirl generator. The Offset of the respective central axis or longitudinal symmetry axes 201b, 202b of the tapered partial bodies 101, 102 to one another creates a mirror image of the neighboring wall Arrangement, each a tangential channel, i.e. an air inlet slot 119, 120 (Fig. 3) through which the combustion air 115 inside the swirl generator 100a, i.e. in flows through the cone cavity 114 thereof. The cone shape of the one shown Partial body 101, 102 has a flow direction certain fixed angle. Of course, depending on the operational use, can the partial body 101, 102 in the direction of flow have an increasing or decreasing taper similar to a trumpet or Tulip. The latter two Shapes are not included in the drawing as they are for the expert can be easily understood. The two tapered partial bodies 101, 102 each have a cylindrical Initial part 101a, 102a, which also, analogous to the tapered Partial bodies 101, 102, offset from one another, so that the tangential air inlet slots 119, 120 via the entire length of the swirl generator 100a are present. In the area of the cylindrical initial part, a nozzle 103 is preferred for a liquid fuel 112, the injection 104 approximately with the narrowest cross section of the formed by the conical part body 101, 102 cone cavity 114 coincides. The injection capacity and the type this nozzle 103 depends on the specified parameters of the respective burner. Of course, the swirl generator can 100a purely conical, i.e. without cylindrical starting parts 101a, 102a. The tapered body 101, 102 also each have a fuel line 108, 109 on which along the tangential air inlet slots 119, 120 arranged and provided with injection openings 117 are, by which preferably a gaseous fuel 113 injected into the combustion air 115 flowing through there is how the arrows 116 symbolize this. This Fuel lines 108, 109 are preferably at the latest End of tangential inflow, before entering the cone cavity 114, placed, this for an optimal Obtain air / fuel mixture. At that through the nozzle 103 fuel introduced 112, as mentioned, normally a liquid fuel, whereby a mixture formation with another medium without any problems is possible. This fuel 112 will tip under one Angle injected into the cone cavity 114. From the nozzle 103 A conical fuel spray 105 is thus formed, which by the rotating combustion air 115 flowing in tangentially is enclosed. In the axial direction, the concentration of the injected fuel 112 continuously through the inflowing Combustion air 115 to mix direction Evaporation reduced. If a gaseous fuel 113 Formed through the opening nozzles 117, the formation occurs of the fuel / air mixture directly at the end of the air inlet slots 119, 120. Is the combustion air 115 additional preheated, or for example with a recirculated This enriches flue gas or exhaust gas sustained evaporation of the liquid fuel 112, before this mixture flows into the downstream stage. The The same considerations also apply when using the lines 108, 109 liquid fuels should be supplied. At the design of the tapered partial body 101, 102 with respect the cone angle and the width of the tangential air inlet slots 119, 120 are strict limits to be observed, so that the desired flow field of the combustion air Set 115 at the output of swirl generator 100a can. Generally speaking, a downsizing of the tangential air inlet slots 119, 120 the faster Formation of a backflow zone already in the area of the swirl generator favored. The axial speed within the Swirl generator 100a cannot be replaced by a corresponding one change the supply of an axial combustion air flow shown. Appropriate swirl generation prevents formation of flow separation within the swirl generator 100a downstream mixing pipe. The construction of the swirl generator 100a is also particularly suitable, the Size of the tangential air inlet slots 119, 120 to change, without changing the length of the swirl generator 100a covers a relatively large operational bandwidth can be. Of course, the partial bodies 101, 102 can also be shifted relative to one another in another plane, thereby even overlapping them can. It is also possible to use the partial bodies 101, 102 by a counter-rotating movement in a spiral to nest. Thus, it is possible to shape the Size and configuration of the tangential air inlet slots 119, 120 to vary arbitrarily, with which the swirl generator 100a can be used universally without changing its overall length is.

The geometric configuration of FIG Baffles 121a, 121b. They have a flow initiation function these, according to their length, the respective End of the tapered partial body 101, 102 in the direction of flow extend towards the combustion air 115. The Channeling the combustion air 115 into the cone cavity 114 can by opening or closing the guide plates 121a, 121b by one in the area of the entry of this channel into the Cone cavity 114 placed pivot point 123 can be optimized, this is particularly necessary if the original gap size of the tangential air inlet slots 119, 120 dynamic should be changed. Of course you can dynamic arrangements can also be provided statically by required guide plates with a fixed component form the tapered partial bodies 101, 102. The can also Swirl generator 100a can also be operated without baffles, or other aids can be provided for this.

5 shows that the swirl generator 100a now made up of four partial bodies 130, 131, 132, 133 is. The associated longitudinal symmetry axes for each partial body are marked with the letter a. About this configuration can be said that because of the generated lower twist strength and in cooperation with one suitably suitably enlarged slot width, the bursting of the vortex flow on the downstream side of the To prevent swirl in the mixing tube, making the mixing tube can best fulfill the role intended for him.

Fig. 6 differs from Fig. 5 in so far as here the partial bodies 140, 141, 142, 143 have a blade profile shape, which is intended to provide a certain flow becomes. Otherwise, the mode of operation of the swirl generator stayed the same. The admixture of fuel 116 in the combustion air flow 115 happens from the inside the blade profiles out, i.e. the fuel line 108 is now integrated in the individual blades. Also here are the longitudinal axes of symmetry to the individual partial bodies marked with the letter a.

7 shows the transition piece 200 in a three-dimensional view. The transition geometry is for a swirl generator 100a with four partial bodies, corresponding to FIG. 4 or 5, built up. Accordingly, the transition geometry points as natural extension of the upstream parts four transition channels 201 on, making up the cone quarter area the partial body mentioned is extended until it hits the wall of the tube 20 respectively. of the mixing tube 220 cuts. The same Considerations also apply when the swirl generator is off another principle than that described under Fig. 2, is constructed. The one running downward in the direction of flow The area of the individual transition channels 201 has an in Flow direction on a spiral shape, which describes a crescent shape, corresponding to the The fact that the flow cross section of the Transition piece 200 flared in the direction of flow. The swirl angle of the transition channels 201 in the flow direction is selected so that the pipe flow then up to A cross-sectional jump at the combustion chamber inlet is still sufficient large distance remains to make a perfect premix with to manage the injected fuel. Further increases the axial speed is also affected by the above-mentioned measures on the mixing tube wall downstream of the swirl generator. The transition geometry and the measures in the area of the mixing tube cause a significant increase in the axial speed profile towards the center of the mixing tube, so that the danger of early ignition is decisively counteracted becomes.

Fig. 8 shows the tear-off edge already mentioned, which on Burner outlet is formed. The flow cross section of the Tube 20 is given a transition radius R in this area, whose size basically depends on the flow within the Tube 20 depends. This radius R is chosen so that the flow applies to the wall and so the swirl number strong can rise. The size of the radius can be quantified Define R so that it is> 10% of the inner diameter d of the tube is 20. Opposite a flow without a radius Now the backflow bladder 50 increases enormously. This Radius R extends to the exit plane of the tube 20, wherein the angle β between the beginning and end of the curvature is <90 °. The runs along one leg of the angle β Tear-off edge A into the interior of the tube 20 and thus forms one Tear-off step S opposite the front point of the tear-off edge A, whose depth is> 3 mm. Of course, here Edge running parallel to the exit plane of the tube 20 based on a curved course back to the exit level to be brought. The angle β 'that is between tangent the trailing edge A and perpendicular to the exit plane of the Tube 20 spreads is the same size as angle β. On the Advantages of this training is already under the chapter "Presentation of the invention" discussed in more detail.

Reference list

10th

Beech ring

20th

pipe

21

Holes, openings

30th

Combustion chamber

31

Openings

40

Flow, pipe flow in the mixing pipe

50

Backflow zone, backflow bubble

60

Burner axis

100a

Swirl generator

101, 102

Partial body

101a, 102b

Cylindrical starting parts

101b, 102b

Longitudinal symmetry axes

103

Fuel nozzle

104

Fuel injection

105

Fuel spray (fuel injection profile)

108, 109

Fuel lines

112

Liquid fuel

113

Gaseous fuel

114

Cone cavity

115

Combustion air (combustion air flow

116

Fuel injection from lines 108, 109

117

Fuel nozzles

119, 120

Tangential air inlet slots

121a, 121b

Baffles

123

Pivot point of the guide plates

124

Openings

125

Inner cone tip

126

Displacement of fuel nozzle 103 upstream from 125

130, 131, 132, 133

Partial body

131a, 131a, 132a, 133a

Longitudinal symmetry axes

140, 141, 142, 143

Vane-shaped partial body

140a, 141a, 142a, 143a

Longitudinal symmetry axes

200

Transition piece

201

Transition channels

220

Mixing tube

d

Inner diameter of the tube 20

R

Transition radius

T

Tangent line of the tear-off edge

A

Tear-off edge

S

Demolition level

β

Transition angle from R

β '

Angle between T and A

Claims (18)

1. Burner for a heat generator, essentially consisting of a swirl generator for a combustion air stream and of means for injecting a fuel into the combustion air stream, wherein there is arranged downstream of the swirl generator (100a) a mixing stage (220), characterized in that [lacuna] has, within a first stage part (200), transition channels (201), running in the direction of flow, for transferring a flow (40), formed in the swirl generator (100a), into a tube (20) located downstream of the transition channels (201), and in that there serves as a means for injecting a fuel a nozzle (103) which is offset upstream by a distance (126) relative to an upstream end of the swirl generator (100a).
2. Burner according to Claim 1, characterized in that the swirl generator has a number of combustion air inlets distributed around the circumference in such a manner that a plurality of combustion air part-streams are formed, and in that the number of transition channels (201) in the mixing stage (220) corresponds to the number of part-streams formed by the swirl generator (100a).
3. Burner according to Claim 1, characterized in that the outlet plane of the tube (20) is designed with a breakaway edge (A) for stabilizing and enlarging a backflow zone (50) which forms downstream.
4. Burner according to Claim 3, characterized in that the breakaway edge (A) consists of a transition radius (R) in the region of the outlet plane of the tube (20) and of a breakaway step (S) offset from this outlet plane.
5. Burner according to Claim 4, characterized in that the transition radius (R) is > 10% of the inside diameter of the tube (20), and in that the breakaway step (S) has a depth of > 3 mm.
6. Burner according to Claim 3, characterized in that a diffuser and/or a Venturi stage is/are arranged upstream of the breakaway edge (A).
7. Burner according to Claim 1, characterized in that the tube (20) located downstream of the transition channels (201) is provided in the direction of flow and in the circumferential direction with orifices (21) for injecting an air stream into the interior of the tube.
8. Burner according to Claim 7, characterized in that the orifices (21) run at an acute angle relative to the burner axis (60).
9. Burner according to Claim 1, characterized in that the throughflow cross section of the tube (20) downstream of the transition channels (201) is smaller than, equal to or larger than the cross section of the flow (40) formed in the swirl generator (100a).
10. Burner according to Claim 1, characterized in that a combustion chamber (30) is arranged downstream of the mixing stage (220), in that, between the mixing stage (220) and the combustion chamber (30), there is a jump in cross section which induces the initial flow cross section of the combustion chamber (30), and in that a backflow zone (50) can take effect in the region of this jump in cross section.
11. Burner according to Claim 1, characterized in that the swirl generator (100a) consists of at least two hollow conical part-bodies (101, 102; 130, 131, 132, 133; 140, 141, 142, 143) fitted one in the other in the direction of flow, in that the respective longitudinal axes of symmetry (101b, 102b; 130a, 131a, 132a, 133a; 140a, 141a, 142a, 143a) of these part-bodies are offset relative to one another in such a way that the adjacent walls of the part-bodies form channels (119, 120) for the combustion air stream (115) which are tangential along their longitudinal extent, and in that the fuel nozzle (103) is arranged, on the head side, upstream of the cone start induced by the swirl generator (100a).
12. Burner according to Claim 11, characterized in that the fuel nozzle (103) is arranged on the burner axis (60).
13. Burner according to Claims 11 and 12, characterized in that the fuel nozzle (103) can be operated with a liquid fuel (112) and further fuel nozzles (117) can be operated with a gaseous fuel (113).
14. Burner according to Claim 13, characterized in that the further fuel nozzles (117) are arranged in the region of the tangential channels (119, 120) along their longitudinal extent.
15. Burner according to Claim 11, characterized in that the part-bodies (140, 141, 142, 143) have a blade-shaped profiling in cross section.
16. Burner according to Claim 11, characterized in that the part-bodies have, in the direction of flow, a fixed cone angle or an increasing cone taper or a decreasing cone taper.
17. Burner according to Claim 11, characterized in that the part-bodies are fitted one in the other spirally.
18. Burner according to Claim 11, characterized in that the throughflow cross section of the tangential air inlet slits (119, 120) decreases in the longitudinal direction of the burner.

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