WO2011000615A1 - Burner, in particular for gas turbines - Google Patents

Abstract

Provided is a burner with a central fuel supply arrangement (27), an annular air channel (17) surrounding the central fuel supply arrangement (27) for supplying combustion air, and swirl vanes (19) disposed in the annular air channel (17). The swirl vanes (19) have first gas nozzles (21) for injecting a gaseous fuel into the combustion air, and second gas nozzles (23) for injecting a gaseous fuel into the combustion air. The first gas nozzles (21) are fed from a first gas distribution channel (29) in the fuel supply arrangement (27), and the second gas nozzles (23) are fed from a second gas distribution channel (31) in the fuel supply arrangement (27). The first gas distribution channel (29) and the second gas distribution channel (31) are supplied with combustion gas from a gas supply pipe (41) which has a first gas supply channel (35) and a second gas supply channel (37), the first gas supply channel (35) being connected to the first gas distribution channel (29) and the second gas supply channel (37) being connected to the second gas distribution channel (31).

Description

description

Burner in particular for gas turbines The present invention relates to a burner and in particular to a gas turbine burner with a central fuel supply arrangement. In addition, the invention relates to a gas turbine. With regard to the global efforts to reduce the

Pollutant emissions from lighting systems, especially in gas turbines, have been developed in recent years burners that have particularly low emissions of nitrogen oxides (NOx). It is often emphasized that such burners are not only with a fuel, but possibly with different fuels, such as oil and natural gas, either selectively or in combination operable to increase the security of supply and flexibility of operation. Such burners are described, for example, in EP 0 276 696 B1.

The burner described in EP 0 276 696 B1 is a hybrid burner for premixing operation with gas and / or oil, as it is used in particular for gas turbine plants. The burner comprises a central fuel supply arrangement, in which also a pilot burner system is integrated, which is operable with gas and / or oil as a so-called diffusion burner or as a separate premix burner. In addition, the possibility for feeding in inert materials is provided. The central fuel supply assembly is surrounded by a main burner system having an air supply annular channel system with a swirler blading therein having a plurality of blades and gas pre-mixing nozzle pipes located upstream of the blades. In addition, in the fuel supply arrangement there are inlet nozzles for oil in the area of the swirl blading, which allow premixing of the main air flow with oil. Instead of EP 0 276 696 B1 by means of nozzle tubes located upstream of the swirl vanes, the fuel gas can also be injected into the air duct through nozzle openings arranged in the swirl vanes themselves, as described, for example, in EP 0 580 683 B1.

In order to increase the control of emissions and combustion stability in the future, in addition to a gas injection by the blade, as in EP 0 580 683 B1, a further gas injection through the blade should be used. This additional gas injection should be controllable separately from the main gas stage, i. In addition to the previously existing gas and oil channels, an additional, second gas channel must be introduced into the central fuel supply device of the burner. One difficulty now is to provide this additional gas channel with fuel, without the previous burner design is changed aerodynamically. This is especially true for the outer contour of the central fuel supply arrangement or the swirl blades, which form the flow channel for the supplied combustion air.

The object of the present invention is therefore to provide a burner, in particular a gas turbine burner, which makes it possible to supply fuel gas to a second gas channel without the outer contour of the central gas channel

Fuel supply arrangement is changed significantly.

It is a second object of the present invention to provide an advantageous gas turbine.

The first object is achieved by a burner according to claim 1, the second object by a gas turbine according to claim 15. The dependent claims contain advantageous embodiments of the invention.

A burner according to the invention has a central fuel supply arrangement and an annular air duct surrounding the central fuel supply arrangement for supplying combustion air on. In the annular air duct swirl vanes are arranged, which have first gas nozzles for injecting a gaseous fuel into the combustion air and second gas nozzles for injecting a gaseous fuel into the combustion air. The first gas nozzles are fed by a first gas distribution channel in the fuel supply arrangement, the second gas nozzles by a second gas distribution channel in the fuel supply arrangement. The first gas distribution channel and the second gas distribution channel are supplied with fuel gas from a gas supply tube having a first gas supply channel and a second gas supply channel, wherein the first gas supply channel is connected to the first gas distribution channel and the second gas supply channel to the second gas distribution channel.

According to the invention, therefore, the two gas distribution channels are supplied with fuel instead of two separate gas supply pipes via a single, common gas supply pipe, wherein in the gas supply pipe for each gas distribution channel a separate gas supply channel is present. Thereby, the contour of the central fuel supply arrangement, as it is known for a single gas distribution channel, approximately according to the burner of EP 0 580 683 B1, even in the presence of two gas distribution channels can be maintained. The gas supply ducts can either be arranged coaxially with one another in the gas supply pipe or next to one another.

If the two gas supply channels according to a first embodiment coaxial with each other in the gas supply pipe, they can be formed by the gas supply pipe comprises an outer tube and an inner tube, wherein the first gas supply channel is formed by the gap between the outer tube and the inner tube and the second gas supply passage from the interior of the inner tube.

Since the inner tube is cooled by the flowing fuel and the outer tube is heated by compressor air, the two tubes may have different thermal Strains result. These can be compensated if the inner tube and / or the outer tube has or have an elastic compensation element which makes or permits axial expansion or compression of the inner tube. In particular, in this case, the inner tube and / or the outer tube may be divided into two axial parts which are interconnected via a bellows. Basically corrugated bellows or bellows come into question. These allow an expansion or contraction of the respective tube and thus a compensation for different thermal expansions.

In the described embodiment of the gas supply pipe, the first gas supply channel has an annular flow cross section and the second gas supply channel has a circular flow cross section. In order to optimize the flow of the gas from the gas supply channels into the gas distribution channels, an adapter piece can be present between the gas supply tube and the gas distribution channels, which cross-sections the annular flow cross-section and the circular flow cross-section with maximum flow areas for the gas flowing into the gas distribution channels. When the adapter piece forms part of the outer circumference of the outer tube and the outer tube has a corresponding recess in the peripheral wall, the adapter can be completely welded to the inner tube and the outer tube, so that the gas channels are sealed against each other.

When the first gas supply channel and the second gas supply channel according to a second embodiment of the gas supply pipe run side by side in the gas supply pipe, the first gas supply channel and the second gas supply channel may each have a flow cross-section with maximum for the flowing gas flow area at least at their ends facing the gas distribution channels. In this way, it is possible to ensure optimal inflow of the gas supplied via the gas supply channels into the gas distribution channels. In the embodiment with two adjacent gas supply channels, the first gas supply channel can be supplied with fuel via a first gas supply connection, while the second gas supply channel is supplied with fuel via a second gas supply connection. These are then arranged adjacent to each other and connected by means of a transition section with the gas supply channels. In this case, in particular a straight connecting line between the first gas supply port and the second gas supply port may include an angle to a straight connecting line between the first gas supply channel and the second gas supply channel, in particular an angle of 90 °.

In addition, the gas supply connections can each have a circular flow cross section. The transition section can then convert the circular flow cross sections in cross sections with maximum flow areas for the flowing gas. In this way, the gas connections can be designed so that they correspond to the previous standard, possibly with the exception of their dimensions.

The gas supply pipe with the juxtaposed gas supply channels can be advantageously designed as a casting, which in particular allows the already described rotation of the straight connecting lines and also can realize a constant wall thickness over the entire component.

A gas turbine according to the invention comprises at least one burner according to the invention. With the burner according to the invention, the flexibility in operating the gas turbine can be increased because a two-stage gas injection into the air supply channel is possible without significant changes to the aerodynamics of the burner are needed. Further features, properties and advantages of the present invention will become apparent from the following description of embodiments with reference to the accompanying figures. FIG. 1 shows the burner according to the invention in a highly schematized schematic diagram. Figure 2 shows a section of a first embodiment of the burner according to the invention in a partially cutaway perspective view.

FIG. 3 shows a burner used in the first exemplary embodiment for the burner according to the invention

Adapter piece.

FIG. 4 shows flow cross sections of the first exemplary embodiment.

Figure 5 shows a detail of the first embodiment.

FIG. 6 shows a second exemplary embodiment of the burner according to the invention in a perspective view.

Figure 7 shows a gas supply pipe of the second embodiment in a perspective view. Figure shows the gas connections of the gas supply pipe of Figure 7 in a perspective view.

In the following, the concept underlying the burner is described with reference to FIG. 1, which shows a burner according to the invention in a highly schematic diagram.

The burner according to the invention, which can optionally be used in conjunction with a plurality of similar burners, for example in the combustion chamber of a gas turbine plant, comprises an inner pilot burner system and a main burner system concentrically surrounding the pilot burner system. Both pilot burner system and main burner system can optionally with gaseous and / or liquid fuels, such as, for example, natural gas or fuel oil operated.

The pilot burner system includes an inner oil supply passage 1 concentrically surrounded by an inner annular gas supply passage 3. This is in turn surrounded by an inner air supply channel or Inertstoffzufuhrkanal 5 concentrically. In addition, a suitable ignition system can be arranged in or on this air supply channel (not shown in the figure). The pilot burner system has a combustion chamber 7 zuwerende outlet opening 9, in whose area a twist blading 11 is arranged in the air supply channel. Gas can be injected from the inner gas supply channel 3 in the area of the swirl blading or upstream of the swirl blading into the air supply channel 5 by means of nozzle openings 13. Oil from the oil supply channel can be injected by means of oil nozzles 15 downstream of the swirl blading into the supplied air or the supplied inert material. The pilot burner system can be operated in a conventional manner with oil and / or gas as a diffusion burner, in which the fuel is injected directly into the flame. However, it is also possible to operate the pilot burner system as a premix burner, in which the fuel is thoroughly mixed with air before the mixture is fed to the flame.

The main burner system surrounding the pilot burner system comprises a radial outer air supply duct 17, also called annular air duct, through which swirl blades 19 of a

Swirl blading extend. These swirl vanes 19 have first gas nozzles 21 and second gas nozzles 23 through which

Fuel gas can be injected into the air flowing through the radial air supply channel 17 air. In the air flowing through the air supply channel 17 air can also by means of oil nozzles 25

Be injected with oil. Although in the present embodiment of oil and oil nozzles talk, but this is only represent representative of suitable liquid fuels and corresponding nozzles.

The first gas nozzles 21 and second gas nozzles 23 located in the swirl vanes 19 and the oil nozzles 25 are supplied with fuel via a radially inner fuel supply arrangement, the so-called hub 27. In this first and second annular gas distribution channels 29 and 31 are arranged, which supply the gas nozzles 21 and 23 with gas. Furthermore, in the hub 27, an annular oil distribution channel 33 is arranged, which supplies the oil nozzles 25 with oil. The gas distribution channels 29, 31 and the oil distribution channel 33 are supplied via gas supply channels 35, 37 and via an oil supply channel 39 with the appropriate fuel. The gas supply channels 35, 37, which supply the gas distribution channels 29, 31 with fuel, are integrated in a common gas supply pipe 41. For the oil supply channel 39 is a separate oil supply pipe 43 before. The integration of the two gas supply channels 35, 37 into a common gas supply pipe 41 has the advantage that the aerodynamics of the burner with respect to the air flowing into the air supply channels 5, 17 compared to a burner with only a single gas supply channel and a single set of gas nozzles not changed. The burner according to the invention can therefore replace existing burners in existing combustion systems without the aerodynamics of the combustion system thereby changing. A first concrete embodiment of the burner according to the invention, in particular the gas supply pipe 41 with the gas supply channels 35, 37 will be described below with reference to Figures 2 to 5. In this exemplary embodiment of the burner according to the invention, the gas supply channels 35, 37 are arranged coaxially with one another in the gas supply pipe 41. The gas supply channel 37 supplying gas to the second annular gas distribution channel 31 is formed by the lumen of an inner tube 35, whereas the first annular gas distributor channel Channel 29 supplying gas supply channel 35 from the cavity between the outer surface of the inner tube 45 and the inner surface of an outer tube 46 is formed. The outer tube 46 forms the outer wall of the gas supply pipe 41.

Since the inner tube 45 is cooled by the gas flowing therethrough and the outer tube 46 is heated by the warm compressor air flowing along, the two tubes 45, 46 experience different thermal expansions. To compensate for this, the inner tube 45 is formed in two parts, wherein between the tube parts 45, 45 ', an elastic compensation element 47 is arranged. In the present embodiment, the elastic compensation element is designed as a bellows, which allows an axial displacement of the two Rohrtei- Ie 45, 45 'against each other. Different thermal expansions between the outer tube 46 and the inner tube 45 can thus be compensated. Instead of the inner tube 45 as in the present embodiment, the compensation element can also be arranged on the outer tube 46. Also, the provision of two compensation elements, one on the inner tube 45 and one on the outer tube 46, is possible. For the compensation element on the outer tube 46, this is analogous with respect to the design of the compensation element on the inner tube 45.

In order to optimize the transition from the gas supply channels 35, 37 to the annular gas distribution channels 29, 31, an adapter piece 49 is provided, which has the annular flow cross section of the first gas supply channel 35 and the circular flow cross section of the second gas supply channel 37 in flow cross sections for the flowing gas transferred maximum flow areas. In this way, the flow from the gas supply channels into the respective annular gas distribution channels can be optimized, whereby more uniform heat transfer coefficients can be achieved and the service life and the lifetime prediction of the burner can be improved. The adapter piece 49 is shown in Figure 3 in a perspective view. It has an approximately semicircular curved edge portion 51 with an outer surface 53, which is adapted in its radius of curvature to the wall of the outer tube 46. In addition, it has a circular projection 55, which can be connected to the inner tube 45. Inside the adapter piece 49, the circular flow cross section and the annular flow cross section are converted into flow cross sections optimized with regard to the creation of maximum flow areas. The optimized ones

Flow cross sections, which result with the aid of the adapter piece at the outlet of the gas supply pipe 41, are shown in FIG. This shows the inlet openings 57, 59, which are provided with flow cross sections corresponding to the maximum flow areas, to the annular gas distribution channels 29, 31.

Figure 5 shows an enlarged detail of Figure 2, in which the arrangement of the adapter piece 49 and the connection with the inner tube 45 and the outer tube 46 are shown. The adapter piece 49 is connected by means of welded connections on the one hand to the hub 27 and on the other hand to the inner tube 45 and the outer tube 46. Due to the only part-circular configuration of the adapter piece 49, which is a semicircular configuration in the present embodiment, it is possible first to weld the adapter piece 49 to the hub 27, then to weld the inner tube 45 on the adapter piece 49 and finally over the outer tube 46 and to weld with the adapter piece 49. If the adapter piece 49 would have a completely annular wall element, in particular the dense bonding of the part of the adapter piece 49 forming the inner gas supply channel to the hub 27 would be difficult to accomplish.

The first specific embodiment described with reference to FIGS. 2 to 5 for the burner according to the invention offers the advantage that a negative influence on the airflow is obtained. Flow can be avoided in particular in the radial air supply channel 17, since no change in the outer hub geometry or the gas supply pipe 41 needs to be made in comparison to a burner with only one gas distribution channel. In addition, the flow cross-sections can be optimally utilized with the aid of the adapter piece, whereby unnecessary pressure losses are avoided. Furthermore, the embodiment according to the first concrete embodiment allows a robust construction, which also allows easy mounting.

A second concrete embodiment for the burner according to the invention will be described below with reference to Figures 6 to 8. Figure 6 shows the hub 27 of the burner according to the invention with a pilot burner 63 arranged in its center and the gas supply pipe 141 in a perspective view. In addition, a burner support 65 can be seen, in which there are two connections 67, 69 for the two gas supply ducts 135, 137 located in the gas supply pipe 141.

The gas supply pipe 141 of the second concrete embodiment is shown in Figure 7 in a perspective view. It differs from the gas supply pipe 41 of the first concrete embodiment in that the gas supply channels 135, 137 are arranged next to each other instead of concentrically with each other. The geometry of the gas supply channels 135, 137 is selected such that there are flow cross sections with maximum flow areas at least at the hub-side outlet end 71 of the gas supply tube.

At the hub-side end 71 facing away from the end of the gas supply pipe 141, the two gas ports for the gas supply pipe 141 are arranged. These are also arranged side by side, but a connecting line A, which connects the centers of the two gas ports 67, 69 with each other by 90 ° with respect to a connecting line B, the centers of the gas supply channels 135, 137 at the hub end of the gas supply pipe 141 connects to each other Turned 90 °. In one Transition portion 73 of the gas supply pipe, a twisting of the gas connections 67, 69 outgoing gas supply channels 135, 137, through which the rotation of the connecting lines A, B is realized. At the same time, the transition from the circular flow cross section of the connections 67, 69 to the flow areas optimized at the hub end 71 of the gas supply pipe 141 takes place in this transition section 73. A view of the gas connections 67, 69 of the gas supply pipe 141 is shown in FIG.

Although in the second concrete embodiment, the gas supply channels 35, 37 of the gas ports 67, 69 to the hub side end 71 of the gas supply pipe 141 toward, wound by 90 °, the twisting can also be done by other angles than 90 °, if another arrangement of the gas ports 67th , 69 in the burner carrier 65 is desired.

The gas supply pipe 141 of the second concrete Ausführungsbei- game for the burner according to the invention can be designed in particular as a cast construction. In such, in particular with a twisting of the channels in the pipe by 90 °, a constant wall thickness over the entire component can be achieved.

The design of the gas supply pipe 141 according to the second specific embodiment offers the particular advantage that the distribution of the gas supply channels in two separate gas connections between the burner carrier and the hub takes place. This simplifies the assembly of the burner. The burner carrier flange is then only provided with two fitting holes. In addition, the tube construction hardly changes the aerodynamics compared to a burner with only one gas distribution channel in the hub. Since the transition section is located in the vicinity of the burner carrier - and thus away from the air ducts of the pilot burner and the main burner - this change in the gas supply pipe leads to a gas supply pipe. With only one gas supply channel, there is no significant change in the aerodynamics of the burner.

Claims

claims A burner having a central fuel supply arrangement (27), an annular air duct (17) surrounding the central fuel supply arrangement (27) for supplying combustion air and swirl vanes (19) arranged in the annular air duct (17), which injector first gas nozzles (21) a gaseous fuel into the combustion air and second gas nozzles (23) for injecting a gaseous fuel into the combustion air, wherein the first gas nozzles (21) from a first gas distribution channel (29) in the fuel supply assembly (27) are fed and the second gas nozzles (23) are fed by a second gas distribution channel (31) in the fuel supply arrangement (27), and wherein the first gas distribution channel (21) and the second gas distribution channel (23) are supplied with fuel gas from a gas supply pipe (41, 141) a first gas supply channel (35, 135) and a second gas supply channel (37, 137), wherein the first gas supply channel (35, 135) with the first Gas distribution channel (29) is connected and the second gas supply channel (37, 137) is connected to the second gas distribution channel (31). 2. Burner according to claim 1, in which the first gas supply channel (35) and the second gas supply channel (37) extend coaxially with each other. A burner according to claim 2, wherein the gas supply pipe (41) comprises an outer pipe (46) and an inner pipe (45), the first gas supply channel (35) from the space between the outer pipe (46) and the inner pipe (35). 45) is formed and the second gas supply channel (37) from the interior of the inner tube (45) is formed. 4. Burner according to claim 3, characterized in that the inner tube (45) and / or the outer tube (46) has or have an elastic compensation element (47) or the axial expansion or compression of the inner Pipe (45) relative to the outer tube (46) enable or allow. 5. Burner according to claim 4, in which the inner tube (45) and / or the outer tube (46) is divided into two axial parts, which are connected via a bellows with each other. 6. Burner according to one of claims 2 to 5, in which the first gas supply channel (35) has an annular flow cross section and the second gas supply channel (37) has a circular flow cross section and between the gas supply pipe (41) and the gas distribution channels (29, 31). an adapter piece (49) is present, which converts the annular flow cross-section and the circular flow cross-section in cross sections with maximum flow areas for the flowing gas. 7. Burner according to claim 6, in which the adapter piece (49) forms a part (53) of the circumference of the outer tube (46) and the outer tube (46) has a corresponding recess in the peripheral wall. A burner according to any one of claims 1 to 7, wherein the first gas distribution channel (29) and the second gas distribution channel (31) are supplied with fuel gas from a common gas supply pipe (141) in which the first gas supply channel (135) and the second gas supply channel (137) run side by side. 9. Burner according to claim 8, in which the first gas supply channel (135) and the second gas supply channel (137) at least at their the gas distribution channels (29, 31) facing ends each have a flow cross section with maximum flow area for the flowing gas. 10. Burner according to claim 8 or claim 9, in which - The first gas supply channel (135) via a first gas supply port (67) is supplied with fuel gas and the second gas supply channel (137) via a second gas supply port (69) is supplied with fuel gas,  - The first gas supply port (67) and the second gas supply port (69) are arranged adjacent to each other and - There is a transition portion (73) which connects the gas supply ports (67, 69) with the gas supply channels (135, 137). 11. A burner according to claim 10, in which a straight connecting line (A) between the first gas supply port (67) and the second gas supply port (69) and a straight connecting line (B) between the first gas supply channel (135) and the second gas supply channel ( 137) enclose an angle between them. 12. Burner according to claim 11, wherein the angle is 90 degrees. 13. Burner according to claim 9 and one of claims 10 to 12, in which the gas supply ports (67, 69) each have a circular flow cross section and the transition section converts the circular flow cross sections in cross sections with maximum flow areas for the flowing gas. 14. Burner according to one of claims 8 to 13, in which the gas supply pipe (141) is a casting. 15. Gas turbine with at least one burner according to one of the preceding claims.