DE4435640A1 - Process and burner for burning dusty fuel - Google Patents

Abstract

In the burner longitudinal axis is an oil ignition lance (1), arranged inside a core air tube (2). The core air tube at its lateral rear end is closed by a plate (2a), through which the oil lance passes, and in the vicinity of its rear end has a lateral aperture (2b). The core air tube is axially displaceably located in a guide tube (4). Joined at right-angles to the guide tube is a core air feed tube (5). The lateral aperture of the core air tube is aligned with the outlet aperture of the core air feed tube with a corresp. axial opening width so that by displacement of the core air tube the air fed via the core air feed tube can enter uninterruptedly in the core air tube.

Description

The invention relates to a method in the preamble of Claim 1 mentioned type.

When burning fuel, in particular dusty coal, nitrogen oxides are primarily formed by oxidation of the contained in the coal Fuel nitrogen. First of all, Hydrogen cyanide (HCN) or ammonia (NH₃). These will then oxidized to nitrogen oxides. It will therefore be at least one aimed at two-stage combustion, initially with one Combustion under substoichiometric conditions (Primary combustion zone) with primary and jacket air is performed so that remaining combustible Components in a subsequent secondary Combustion zone to be burned. In this tiered Combustion must have a small air ratio in the Primary combustion zone ensures ignition stability stay d. H. it must be for particularly good interference of the fuel components to be ignited first will.

Because sub-stoichiometric in the primary combustion zone is burned, a relatively high tertiary or Step air percentage as late as possible, but especially good to be mixed in. At the same time, the possibility of  Flue gas from the combustion chamber surrounding the flame into the Be sure to suck in the flame.

It follows that for the operation of such Brenner has the greatest possible number of degrees of freedom for burner optimization to reduce the formation of Nitrogen oxides should be available. With the from the DE 42 17 879 A1 known process management becomes this Purpose the tertiary air in one the twisted jacket air surrounding ring beam supplied from the annulus of a the jacket air pipe surrounding tertiary air pipe emerges. Sheathed air pipe and tertiary air pipe are each with one spiral inlet housing and with separate Air inlet lines connected. Beyond that inside the primary air tube on the core air tube attached swirl insert provided, the one a uniform flow through the primary air pipe Rotational flow generated. At the same time the Coal dust within the mixture flow on the outer circumference enriched the primary air pipe; upon leaving the The primary air tube is the ring arranged there Coal dust concentration torn up in the edge area, which creates recirculation vortices. These Recirculation vortices ensure an accelerated Heating up the coal dust and sufficient Mixing the coal dust with part of the Jacket air. The coal dust concentration on one defined place in the burner muffle Occasion of a very severe lack of air in the location and time with the initial phase of the coal dust goes along. The primary air pipe is a right-angled one Inlet elbow upstream.

The disadvantage is that for changing the Coal dust distribution in the primary air pipe Primary air flow requires a swirl insert is. Furthermore, the stepped air ring jet leaves none expect sufficient penetration depth of the step air.  

It is therefore the object of the present invention Specify method of the generic type, in which the Burner optimization with regard to the reduction of Formation of nitrogen oxides is further improved.

This problem is solved in that before tearing open the coal dust concentration in the edge area Flow rate of the primary air is changed and the step air in a the primary combustion zone surrounding wreath of individual rays is introduced in such a way that a swirl is imparted to the total stage air.

The change in flow rate can be caused by Retraction of the cross-section take place, whereby the Coal dust concentrated, accelerated and heading of the inner one developing in the primary combustion zone Recirculation area is distracted. By tearing open the Coal dust concentration in the edge area becomes fine dust the concentrated dust flow to the outside transported and mixed into the jacket air stream.

On the other hand, the flow cross section can be expanded which slows down the gas flow. At the same time, the separation of fine dust occurs because this follows the expansion most quickly. By the Tearing up the coal dust concentration in the edge area, at which is primarily fine coal dust, swirling takes place, transport of fine dust after outside and quick mixing of the fine dust into the Jacket air.

The process management on the one hand sufficient ignition stability achieved and on the other hand good mixing of the step air into the secondary Combustion zone allows. By separating the Step air in individual jets ensures that a sufficient depth of penetration is achieved and that between  the single jets of flue gas from the combustion chamber into the flame can occur.

It always becomes an internal primary Combustion zone with a low air ratio and a external, oxygen-rich, stable flame envelope achieved from which the fuel-rich flame retards with Oxygen is supplied. Due to the possible entry of Flue gas in the flame envelope can prevent the supply of Oxygen to the fuel-rich flame is further delayed will.

The invention is also directed to a burner in the Claim 4 mentioned type, as well as dependent on this Subclaims 5 to 14. Furthermore, the present invention on a burner according to the preamble of claim 15, the main objective of which is simple even application of air to the primary air pipe Air-fuel mixture is.

This object is achieved by the features of the characterizing part of claim 15. The burner according to claim 15 can be used with particular advantage in a burner according to at least one of claims 4-14, since the flame holder 19 can be supplied with a particularly evenly distributed primary air. The subclaims 16-18 relate to advantageous embodiments of the burner according to claim 15.

Various embodiments of the invention are shown in FIGS Drawings are shown and are described in more detail below explained.

It shows:

Fig. 1 shows a longitudinal section through a first embodiment of the burner according to the invention, in which a recovery is provided on the outer circumference at the coal dust outlet,

Fig. 2, showing the forming of the strand of pulverized coal and the gas flow, wherein the gas inflow is a partial section through the torch head of FIG. 1 from below,

Fig. 3 is a view comparable to Fig. 2, wherein the incident flow is from the top,

Fig. 4 is a partial perspective view of the burner head for explaining the arrangement of which is arranged at the inlet end of the primary air pipe rays breaker in "transparent view"

Fig. 5 is an enlarged partial view of the flame holder of FIG. 1,

Fig. 6 is a partial plan view from the right of the burner of FIG. 1

Fig. 7 shows another embodiment of the flame holder,

Figure 8 is a developed view taken along the line VIII-VIII in FIG. 1, two for representing the position of the stage air nozzles and their construction in the form of subchannels.,

Fig. 9 is a partial view similar to Fig. 6 and illustrating the adjustment positions of the individual nozzles,

Fig. 10 is a longitudinal section through the outlet end of a rotatably mounted in a guide tube Stufenluftdüse,

Fig. 11 is a plan view of the nozzle end in FIG. 10 in the direction of arrows XI-IX in FIG. 10,

FIG. 12 is a plan view of the outlet end of the nozzle according to FIGS. 10 and

Fig. 13 is a diagram illustrating the primary air flow, outer air flow (secondary air flow) and stage air flow (tertiary air flow).

Fig. 1 shows a longitudinal section through an embodiment of the burner according to the invention. An oil ignition lance 1 is provided in the longitudinal axis of the burner and is arranged within a core air tube 2 . The flame cone 3 of the oil pilot flame is indicated schematically in the figure. The core air tube is closed at its rear end by a plate 2 a, which is penetrated by the oil lance, and has a side opening 2 b near its rear end. Furthermore, the core air tube is axially displaceable - as indicated by the arrow P - in a guide tube 4 . At right angles to the guide tube 4 , a core air supply tube 5 is connected to it. The outlet opening of the core air supply tube 5 is assigned to the side opening 2 b of the core air tube 2 and provided with a corresponding axial opening width such that when the core air tube is displaced, the air brought in via the core air supply tube can enter the core air tube unhindered.

The front section of the core air tube is surrounded by a primary air tube 6 to form a cylindrical ring channel, the outlet opening of which is set back relative to the outlet opening of the core air tube.

The core air tube is charged with a coal dust-gas mixture in the following way. The coal dust-gas mixture brought up from a coal grinding plant or coal dust source, not shown, is fed to a deflection manifold 7 upstream of the burner, in which a concentration of the coal dust K is forced on the side of the manifold facing the combustion chamber.

The deflection manifold 7 is preferably a continuously curved manifold. As FIGS. 2 and 3 show, this forced concentration takes place regardless of whether the inflow is from below ( FIG. 2) or from above ( FIG. 3). The manifold 7 is followed by a channel extension 8 serving as a delay channel, which in the embodiment shown is a channel with a rectangular cross section, ie there is an expanding transition from a line with a round cross section to a line with a rectangular cross section. In the delay channel, the flow rate of the gas from z. B. reduced 23 m / s to 12 m / s, which also reduces the coal dust speed. In addition to slowing the flow, at least partial segregation of the coal dust-gas mixture is achieved in the delay channel 8 , as is shown schematically in FIGS. 2 and 3 by the coal dust K and the gas flow G. In the case of a vertical flow from below or above, the formation of the dust streak K can be determined by a corresponding geometric design of the entry of the coal dust line into the delay channel.

The strand of coal dust K which has already slowed down hits a strand breaker 9 at the end of the delay duct 8 . The strands breaker 9 is composed of a plurality of rod-shaped crushing elements 10, which are a 11 a venturi-like inlet assembly 11 upstream along a predetermined circle sector of the inlet opening and extending substantially parallel to the burner axis. In the embodiment shown in FIG. 4, the crusher elements consist of cuboids arranged at a distance. The crushing elements can be easily replaced when worn.

The inlet assembly 11 surrounds the end of the guide tube 4 facing the combustion chamber, forming an annular channel. The gas flow applied to the rear wall of the delay channel is deflected by a closing plate 12 , preferably extending at an angle of 45 ° and penetrated by the guide tube 4 , into the annular inlet opening of the inlet assembly 11 and strikes the delayed and through the at an angle of almost 90 ° Breakwater broken dust flow. This ensures that the coal dust is evenly distributed over the ring cross-section. The venturi-like design of the inlet assembly 11 accelerates the gas flow parallel to the burner axis. As a result of the vortex formation that occurs at the outlet of the venturi assembly, any local strands of coal dust that may be present on the circumference are dissolved, whereby coal dust and gas are mixed. The constriction of the free cross-section in the entry assembly can be between 10-70%. At the same time, the gas flow is blocked, which results in a further equalization.

As can be seen in particular from FIGS. 1-4, the closing plate 12 together with the associated side walls 13 and 14 , as well as the end wall 15 carrying the crushing elements 10 together with the inlet assembly 11 constitute a structural unit which is connected to the side wall 16 facing away from the combustion chamber a of a cabinet air box 16 is connected by a screw 17 . Components 12 , 13 , 14 and 15 form an intake manifold. After establishing the connection, the inlet assembly 11 projects into the primary air pipe 6 , which is welded to the side wall 16 a.

For the primary flame, a hot, strongly substoichiometric, compact primary combustion zone with the most complete pyrolysis of the fuel and internal fuel grading is sought. An air ratio of 0.4-0.6 should be achieved in the primary flame. For this purpose, such a design is sought at the dust outlet end of the primary air pipe 6 that, on the one hand, a gradation of the fuel input into the primary flame is achieved and, on the other hand, a stable and fast ignition of the coal dust is supported. For this purpose, the aim is to concentrate and slow down the fine dust on the outer circumference of the dust outlet in order to ensure rapid mixing with the jacket air, which is supplied via a jacket air pipe which concentrically surrounds the primary air pipe 6 , forming a cylindrical ring channel. For the coarser fraction, it is necessary to transport it into the inner recirculation zone of the primary flame that is being formed at higher speeds. It should therefore be aimed for, when the dust flow enters the inner recirculation zone of the flame, a cross-flow screening of the coal dust takes place, so that the finer particles are deflected relatively quickly into the combustion zone and the coarsest particles penetrate the furthest into the recirculation area. In this way it can be ensured that with increasing particle size there is a longer period of time for heating and pyrolysis and that there is a delayed continuous introduction of fuel into the primary flame.

In order to achieve these goals, a flame holder 19 is assigned to the outlet end of the primary air pipe 6 in the embodiment according to FIG. 1, the end of the flame facing the combustion chamber is shown on an enlarged scale in FIG. 5. This flame holder consists of a tubular channel 20 with a straight cylindrical section 20 a, a conically tapering section 20 b and a conically widening section 20 c. The channel overlaps with its straight cylindrical end 20 a the free edge of the primary air tube and is supported by means of radially extending webs 21 on the end of the core air tube 2 , so that when the core air tube 2 is displaced, the flame holder 19 moves in a corresponding manner (see FIG. 1 and 6). In the area of the indentation of the channel 20 given by the sections 20 b and 20 c, blocking teeth 22 are provided which protrude into the primary flow and are arranged in a uniform circumferential distribution. Instead of individual locking teeth, a toothed locking ring can also be provided. By drawing in the cross section of the channel 20 , the coal dust in the coal dust-gas mixture is concentrated, accelerated and deflected in the direction of the inner recirculation area of the flame forming at the burner mouth. The blocking teeth in the area of the narrowest cross-section cause a swirling of the flow in the outer area, as a result of which fine dust in particular is discharged from the concentrated flow and transported away to the outside. The turbulence of the flow also favors the mixing of the fine dust into the jacket air flow. The accelerated and inwardly deflected coarse dust reaches the inner recirculation zone, where the coal dust is cross-viewed by the recirculation flow. The fuel input into the primary flame is thus classified several times.

By changing the position of the flame holder 19 by moving the core air pipe 2 relative to the coal dust pipe 6 , an optimization between the deflection inwards and acceleration of the coal dust can take place.

Another possibility for the design of the channel of a flame holder is shown in FIG. 7. The channel 23 there has a straight cylindrical section 23 a and an adjoining conically widening section 23 b. Blocking teeth 24 , comparable to blocking teeth 22 , are formed near the outlet end of the widening section 23 b. It should be pointed out that separate locking teeth may not be required, but that a continuous locking ring may be sufficient.

In the embodiment of Fig. 7 is performed by the extension of the dust cross section in the channel portion 23 b slowing the gas flow and there is a velocity profile with an outer and an inner slower faster flow. At the same time, a separation of fine dust occurs, since this follows the expansion most quickly, ie the coal concentration will be higher in the area adjacent to the core air pipe than in the outer, slower flow, since the coarser coal particles will keep their direction of flow. The blocking teeth 24 cause a further slowdown of the dust in the outer region of the coal dust cross section and a swirling of the flow, which favors the transport of the fine dust to the outside and thus its rapid mixing into the jacket air. The coarser dust is only slowed down comparatively little by the delayed flow. It reaches the inner recirculation area at a relatively high speed, where cross-flow screening of the coarser dust takes place. Overall, a multiple gradation of the fuel in the primary flame is also achieved in this embodiment. The widening of the coal dust cross section also causes a dynamic separation of the jacket air from the main flow of the coal dust, which also favors a stepped fuel input into the primary flame.

A device for influencing the swirl in the form of rotatably mounted axial swirl flaps 25 is arranged in a section of the jacket air pipe 18 that widens toward the inflow end and can be adjusted from the outside via a linkage 26 and an actuator. These axial swirl flaps impose a swirl of adjustable size on the jacket air.

A muffle 27 constructed of a ceramic mass adjoins the end of the jacket air tube 18 facing the combustion chamber and extends towards the combustion chamber with an S-shaped configuration of its inner surface. This muffle shape combined with the corresponding design of the coal dust outlet and a strong swirling of the jacket air with the help of the swirl flaps 25 guarantees a quick intensive ignition. Due to the high peripheral speed of the jacket air and an appropriate design of the dust outlet cross-section, a rapid mixing of fine dust into the jacket air is realized. The S-shape of the muffle, which can be seen in particular in FIG. 1, prevents the primary flame from tearing open even with a high swirl intensity of the jacket air. The S-shape runs out to the combustion chamber in such a way that an outflow of the jacket air can take place with a flow component almost parallel to the burner axis. A compact primary flame, a smaller but more intensive (higher backflow speed) internal recirculation zone and a stronger external recirculation of the flue gas are thus achieved through the alleys between the step air nozzles 28 to be explained below. As already mentioned, the core air tube 6 and the flame holder 19, and thus the dust outlet cross section, are axially displaceable to control the course of the combustion in the primary flame. With a corresponding design of the coal dust outlet cross section, the exit speed of the jacket air and the location and speed of the mixing of the coal dust into the jacket air can be influenced by shifting the inner outlet cross section. The location and intensity of the ignition and the grading of the fuel within the primary flame can thus be set. In addition to the possibility of controlling a certain combustion process in the primary flame, the shift in the coal dust outlet cross-section can react very well to a wide variety of coal qualities with regard to ignition and combustion behavior.

The secondary combustion will now be described with reference to FIGS. 1, 6 and 8-12.

In the secondary combustion area, a furnace should also be used Burnout air has an air ratio of 0.9-1.05 and at one Firing without burnout air an air ratio of 1.1-1.3 can be achieved.

In order to achieve a secondary combustion is provided around the burner muffle 27 around a rim of a plurality of stages of air nozzles 28, wherein the steps of air nozzles in the muffle 27 forming ceramic mass KM are embedded. Eight spaced stage air nozzles 28 are preferably provided. The arrangement of the stepped air nozzles 28 is intended, on the one hand, to allow adequate external recirculation to the primary flame and to keep the oxygen away from the primary flame for a sufficiently long time, and on the other hand to securely enclose the primary flame in an oxygen-rich gas flow. By using individual nozzles in comparison to an annular nozzle surrounding the muffle, a high penetration depth of the oxygen-rich gas flow is to be achieved. As can be derived from the figures, in particular FIG. 9, the nozzles 28 are initially arranged with an angle of incidence directed outward from the burner axis in order to avoid direct rapid mixing of the step air into the primary flame which is formed. In the figures, the air nozzles 28 are all shown with the same outward angle of attack. However, it is also possible to assign differentiated axial angles of attack to the nozzles and thus to achieve a multiple air gradation within the flame.

As can be seen in particular from FIG. 9 in conjunction with FIGS . 1 and 8, the stepped air nozzles 28 not only have a radially outward angle of attack, but also a tangential angle at the same time, ie they extend so that the nozzle axis Torch axis does not cut. A swirl is thus imparted to the step air flow, so that a "pneumatic muffle" concentric with the muffle 27 is formed. A swirl is preferably applied to the step air flow which is in the same direction as the swirl imparted to the jacket air flow by the swirl flaps 25 . This stabilizes the flow and prevents the step air flow from mixing too quickly with the flow of the primary flame.

The jets emerging from the stepped air nozzles 28 draw flue gas RG out of the flame environment as they flow out, as a result of which the oxygen partial pressure in the secondary combustion zone drops and the NO _x formation in this area is reduced.

Although the nozzles with a constant discharge angle can be used as stepped air nozzles, it is advantageous if nozzles with a variable discharge angle are used. To achieve this, two-channel nozzles are used, the design of which can be read in particular from FIGS. 10-12.

The two-channel nozzle 28 has a straight cylindrical section 28 a, in which a partition 29 is arranged. According to the desired flow distribution, the partition does not have to be arranged in the center, but can be arranged offset from a radial plane. The partition wall 29 ends at a distance from an outlet opening 30 which is inclined with respect to the nozzle axis A. The outlet opening 30 is formed by remaining pipe sections 28 b by means of suitable sections of a tube, and 28 c as well as the axis A inclined with respect to an inclined at a first angle relative to the axis A cover plate 31 and through a with respect to another predetermined angle cover plate 32 is limited.

The angles of the cover plates 31 and 32 determine the possible exit angles with which a gas flow can exit the exit opening 30 .

A different exit angle with respect to the axis A can be achieved by volumetrically different action of the channels 33 or 34 determined by the partition 29 with step air. It can e.g. B. be possible that when the channels 33 and 34 are loaded with 50% of the step air, the step air jet emerges parallel to the cover plate 31 or that when the channel 33 is loaded with 10% of the step air and the channel 34 with 90% of the step air of the nozzle 28 the beam emerges parallel to the cover plate 32 .

For the different loading of the two channels 33 and 34 , as can be seen from FIG. 1, provision is made for two inner walls 36 and 37 to be provided in the air box 16 in addition to the side wall 16 a and the side wall 35 shown on the right in the air box 16 . The inner wall 36 separates the step air from the jacket air and the inner wall 37 separates the step air into two partial flows. The space between the partition walls 36 and 37 is connected to the sub-channels 34 of the stepped air nozzles 28 via the passage sections 38 passing through the space between the partition walls 37 and 35 , while the sub-channels 33 are connected directly to the space between the side wall 35 and the partition wall 37 . The action of the channels 33 and 34 with different air flows is made possible by adjusting the air entering the spaces between the partition 36 and 37 or 37 and 35 by means of control flaps 39 and 40 . With regard to FIG. 8, it should be noted that this represents a development along the line VIII-VIII in FIG. 1, while FIG. 1 shows a section along the line II in FIG. 8.

The above-described loading of the subchannels 34 takes place via channels 38 rigidly connected to them.

Another connection configuration is required if the stepped air nozzles 28 are each individually rotatable at least over a partial area. For this purpose, the individual nozzle is rotatably supported in a guide tube 39 . With such an arrangement, both the tangential and the radial inflow angle would be adjustable and thus a particularly good optimization of the air gradation on the burner could be achieved. The application of subchannels 33 and 34 would, however, be more complicated.

It is also contemplated that individual stage air vents lockable to the required Exit speeds of the step air also in To be able to implement part-load operation.

It goes without saying that the amount of primary air, core air and jacket air can also be regulated. In Fig. 13, control valves 41, 42 and 43 are shown which shows a schematic of the burner by a blower 44 and supplied air flows supplied from a coal mill 45 fuel. The control flap 41 regulates the jacket air and the step air upstream of the control flaps 39 and 40 simultaneously. The control flap 42 controls the primary air supplied via a pressure-increasing blower 42 a and the control flap 43 controls the core air insofar as the core air pipe has to be acted on.

As can be seen from FIG. 1, the muffle 27 is formed in a pipeline basket 46 which is integrated into the water vapor circuit of a steam generator and which is connected to the wall bore 47 of the combustion chamber and burns into the burner. Insulation 48 is also provided in the area of the muffle.

Claims (18)

1. A method for the combustion of dusty fuel, in particular coal, by means of a burner with a primary air pipe leading a mixture of air and fuel (primary air) and a jacket air pipe leading and surrounding the primary air pipe, in which the primary air and swirled jacket air enter a burner muffle with formation emerge from a primary combustion zone with an internal recirculation area, in which, when the primary air emerges, the coal dust concentration in the edge region of the primary air pipe is torn open with the production of eddies and in which the swirled step air is fed to the primary flame, characterized in that, before the coal dust concentration in the edge region is torn open, the flow velocity of the primary air is changed and the step air is introduced into a ring of individual jets surrounding the primary combustion zone in such a way that a swirl is imparted to the total step air. 2. The method according to claim 1, characterized, that the change in flow rate through The cross section is drawn in.   3. The method according to claim 1, characterized, that the change in flow rate through Expansion of the flow cross section takes place. 4.Burner for the combustion of dusty fuel, in particular coal, with a primary air pipe carrying a mixture of air and fuel (primary air), a jacket air pipe carrying jacket air and surrounding the primary air pipe, to which a burner muffle is connected, and a device for supplying swirled step air, wherein the outlet end of the primary air pipe is assigned a flame holder with a barrier projecting into the primary air, characterized in that the barrier ( 22 ; 24 ) of the flame holder ( 19 ) is preceded by a change in the cross section for the primary air flow and that a supply of the step air is provided the ring surrounding the burner muffle is provided by stepped air nozzles ( 28 ) which are made tangential at least with respect to the burner axis in such a way that a twist is imparted to the stepped air. 5. Burner according to claim 4, characterized in that an oil ignition lance ( 1 ) receiving core air tube ( 2 ) is arranged within the primary air tube ( 6 ). 6. Burner according to claim 4 or 5, characterized in that the flame holder ( 19 ) is arranged displaceably relative to the primary air pipe ( 6 ). 7. Burner according to at least one of claims 4-6, characterized in that the flame holder ( 19 ) is connected to an axially displaceable core air tube ( 2 ). 8. Burner according to at least one of claims 4-7, characterized in that the cross-sectional change is a cross-sectional constriction ( Fig. 1; Fig. 5) and the obstruction ( 22 ) is arranged in the region of the narrowest cross-section. 9. Burner according to at least one of claims 4-7, characterized in that the cross-sectional change is a cross-sectional expansion ( Fig. 7). 10. Burner according to at least one of claims 4-9, characterized in that the muffle ( 27 ) has a substantially S-shaped cross section in the direction of the burner axis such that air flows into the muffle or from the substantially parallel to the burner axis Muffle flows out into the firebox. 11. Burner according to at least one of claims 4-10, characterized in that the stepped air nozzles ( 28 ) are additionally set radially outwards. 12. Burner according to at least one of claims 4-11, characterized in that the stepped air nozzles ( 28 ) are nozzles with a variable outflow angle. 13. Burner according to at least one of claims 4-12, characterized in that the step air nozzles ( 28 ) have two channels ( 33 , 34 ) which can be acted upon in different ways with the step air and which are in at least two at different angles against the nozzle axis (A ) open inclined plates ( 31 , 32 ) limited vestibule, from which the air can exit via an outlet opening ( 30 ) inclined to the axis (A) of the nozzle. 14. Burner according to at least one of claims 4-13, characterized, that the nozzles are rotatably mounted about their longitudinal axis. 15. Burner for burning dusty fuel at least with a mixture of air and fuel (primary air) leading primary air pipe and with an upstream of the primary air pipe inlet manifold, in particular burner according to one of claims 4-14, characterized in that in addition a deflection manifold ( 7 ) is provided and that between the deflection manifold ( 7 ) and the inlet manifold ( 12 , 13 , 14 , 15 ) is arranged in its cross-section compared to the cross section of the deflection manifold extended delay channel ( 8 ) and at the end of the delay channel ( 8 ) in the area A strand breaker ( 9 ; 10 ) is arranged in the deflecting elbow and through the delay duct, a strand breaker ( 9 ; 10 ) and the gas flow (G) passing through the delay duct is deflected in the inlet manifold in such a way that the gas flow (G) is at a predetermined angle to the at least Partial strands of broken fuel streak (K) strikes and air and coal dust enter the primary air pipe ( 6 ) in an even distribution. 16. Burner according to claim 15, characterized in that the entry into the primary air pipe ( 6 ) is preceded by a blockage ( 11 ). 17. Burner according to claim 15 or 16, characterized in that the blockage ( 11 ) is venturi-like. 18. Burner according to at least one of claims 15-17, characterized in that the strand breaker ( 9 ) consists of a plurality of bar-shaped breaking elements ( 10 ) arranged at a distance and preferably on a circular sector.