EP3845810B1

EP3845810B1 - Supporting device for a heat-insulating tiles of a combustion chamber of a gas turbine assembly for power plants and a gas turbine assembly

Info

Publication number: EP3845810B1
Application number: EP19425104.7A
Authority: EP
Inventors: Daniele Licata; Valerio Pistone
Original assignee: Ansaldo Energia SpA
Current assignee: Ansaldo Energia SpA
Priority date: 2019-12-31
Filing date: 2019-12-31
Publication date: 2023-11-22
Anticipated expiration: 2039-12-31
Also published as: CN113124419A; EP3845810A1; CN113124419B

Description

Field of the Invention

The present invention relates to the technical filed of the gas turbine assembly for power plants. As known, in a gas turbine assembly (in the following only gas turbine) an incoming air flow is compressed by a compressor and combusted with an added fuel in a combustion chamber for producing a hot gas flow to be expanded in a turbine for generating a rotating work on a rotor in turn connected to a generator. Due to the high temperature, the inner surface of the combustion chamber is provided with a plurality of heat-insulating tiles preferably made of refractory or ceramic material. In view of the above, in detail the present invention refers to a supporting or holding device configured for supporting or keeping in position the heat-insulating tiles on the inner surface of the combustion chamber.

Description of prior art

As known, a gas turbine assembly for power plants comprises a compressor assembly, a combustor assembly and a turbine assembly. The compressor assembly is configured for compressing incoming air supplied at a compressor inlet. The compressed air leaving the compressor assembly flows into a volume (called "plenum") and from there into the combustor assembly. This combustor assembly comprises usually a plurality of burners configured for injecting fuel (oil and/or gas fuel) in the compressed air flow. The mixture of fuel and compressed air enters a combustion chamber where this mixture is combusted. The resulting hot gas flow leaves the combustion chamber and drives in rotation the turbine assembly that performs a work on the rotor (in turn connected to a power generator). As known, the turbine assembly comprises a plurality of stages, or rows, of rotating blades that are interposed by a plurality of stages, or rows, of stator vanes. The rotating blades are supported by the rotor whereas the stator vanes are supported by a casing (called "vane carrier") that is concentric and surrounding the turbine assembly.
In order to achieve a high efficiency, the hot gas flow has to disclose a very high turbine inlet temperature. However, in general this high temperature involves an undesired high NOx emission level. In order to reduce this emission and to increase operational flexibility without decreasing the efficiency, a so called "sequential" gas turbine is particularly suitable. In general, a sequential gas turbine comprises a first and a second combustor or a first and a second combustion stage wherein each combustor is provided with a plurality of burners and with at least a relative combustion chamber. Today at least two different kinds of sequential gas turbines are known. According to a first embodiment, the first and the second combustor are annular shaped and are physically separated by a stage of turbine blades, called high pressure turbine. Downstream the second combustor a second turbine unit is present (called low pressure turbine). According to a second embodiment of a sequential gas turbine, the gas turbine is not provided with the high pressure turbine and the combustor assembly is realized in form of a plurality of can-combustors arranged as a ring around the rotor. Each can-combustor comprises a first combustor and a second combustor arranged directly one downstream the other inside a common can shaped casing. These two example of gas turbine assemblies have been cited only as non-limiting examples wherein the present invention can be applied. Moreover, the present invention may also be applied in gas turbines having a single combustion stage.
As known, the inner surface of the combustion chamber of gas turbines must be provided with a heat-insulating layer made of refractory material, because of the high temperatures which are developed during operation. The heat-insulating layer is generally formed by a plurality of ceramic tiles arranged in continuous rows on the inner surface of the combustion chamber casing or combustion chamber shell, so as to define an essentially continuous heat-insulating surface. According to know solution, each refractory tile is supported in position by a supporting device housed in part (by sliding) in grooves obtained on the inner surface of the combustion chamber casing. The supporting devices need to have an elastic and spring features for keeping the ceramic tiles in position in all gas turbine working condition. According to the closest prior art solution, the supporting device comprises a plate configured to be housed by sliding in a groove of the combustion chamber casing and a hooked head protruding orthogonally outside the groove and configured to be coupled to an edge of the tile. An example of this known hooked supporting device is disclosed in EP2741001 . The hooked head comprises in series two portions; a first portion extending orthogonally from the plate and a second portion parallel to the plate. For allowing the coupling, the edge of the tile can be provided with a lateral groove for housing the second portion of the hooked head. This hooked supporting device is made by metallic material and due to the high temperature it needs to be cooled. For this cooling purpose, the combustion chamber casing comprises holes for feeding cooling air running outside the combustion chamber to the supporting device.
Starting from this prior art configuration, schematically represented in figure 3, today there is the need to improve the cooling of this hooked supporting devices in order to avoid overheating of the supporting device itself and hot gas ingestion problems. Indeed, as a direct consequence of this undue overheating the support may lose the spring and elastic functions and the tile and/or the metallic shell of the combustion chamber can be damaged.
US2006176671 discloses a heat shield comprising heat shield elements and securing elements for securing the heat shield elements.

Disclosure of the invention

Accordingly, a primary object of the present invention is to provide a supporting or holding device for supporting or keeping in position a heat-insulating tile (preferably a ceramic tile) of a combustion chamber of a gas turbine assembly for power plant. Indeed, as known, the inner metallic surface of the combustion chamber has to be thermally protected due to the extreme high hot gas temperature and the protective layer is realized by a plurality of heat-insulating tiles. In view of the above, according to the preamble of the present invention, each supporting device comprises:

a plate configured to be housed (preferably by sliding) in a groove obtained on the inner surface of the combustion chamber;
a hooked head at one end of the plate and configured to be coupled to a side of the tile (preferably to a groove obtained in a side of the tile); the hook-shape of the head is defined by two portions in series, namely a first portion orthogonal to the plate and protruding from the casing groove inside the combustion chamber and a second portion orthogonal to the first, parallel to the plate and directed towards the tile (i.e. inside the groove of the tile).

figure 3

EP2741001

According the main feature of the invention, the supporting device moreover comprises at least an additional element or body, i.e. the claimed at least an intermediate or spacing device, that is coupled to the hooked head and is configured for realizing a cooling channel between the hooked head and the tile. Therefore, according to this feature a space is present between the hooked head and the tile (space defined by the interposition of the intermediate device) so that cooling air fed at the plate can flow in this channel and reach at least part of the metallic hooked head. Advantageously, in this way the cooling of the supporting device is improved avoiding any overheating.
According to an embodiment of the invention, the intermediate device comprises two bodies coupled to the first portion of the hooked head, wherein these two bodies are spaced each other for realizing a cooling channel between them along the first portion of the hooked head.
Advantageously, in this way the cooling air flow can rise along the entire extent of the first portion of the hooked head.
Starting from the above embodiment, these two bodies may have an extension less than the first portion of the hooked head so that to realize two upper lateral cooling channels between the upper edges of the bodies and the second portion of the hooked head. In this way the cooling air flow can rise along the entire extent of first portion towards the connection between the first and second portion of the hooked head and from there it can flow outside the supporting device passing by the upper channels.
Advantageously, in this way the cooling air flow can reach also the connection between the first portion and second portion of the hooked head and it avoid hot gas ingestion.
According to an alternative embodiment of the invention, the intermediate device may be realized in form of a single body coupled to the first portion of the hooked head. According to this embodiment, the single body is spaced from the first portion of the hooked head and comprises an opening facing at one side the first portion of the hooked head and at the opposite side the side of the tile. This channel may be realized in form of a recessed portion of the first portion of the hooked head.
Starting from the above embodiment (single body), the intermediate or spacing device can also be coupled to the second portion of the hooked head. In this case the single body is configured also for realizing cooling channels between the body itself and the second portion of the hooked head.
Preferably, i.e. in any foregoing embodiment, the hooked head may be T shaped.
Preferably, i.e. in any foregoing embodiment, at the connection between the plate and the first portion of the hooked head the supporting device may be provided with a passing hole for allowing the cooling air (coming by passing holes obtained in the combustion chamber casing) to enter the claimed channel realized by the intermediate or spacing device between the tile and the hooked head.
Preferably, i.e. in any foregoing embodiment, at the connection between the first portion and the second portion of the hooked head of the supporting device may be provided with at least a passing hole connected to the cooling channel so that the cooling air can avoid any hot gas ingestion.
Finally, the supporting device may comprise an additional hooked head with the relative spacing device at the opposite end of the plate.
As foregoing mentioned, the present invention not only refers to supporting device itself but may be extended to the any gas turbine assembly for power plant comprising at least a supporting device as claimed in the enclosed claims. The minimal components defining a gas turbine that can be provided by the present invention are a compressor unit, at least a combustion unit and at least a turbine unit wherein the combustion unit comprises at least a combustion chamber defined by a casing provided with a plurality of groves. As foregoing described, a plurality of tiles are provided for heat-insulating the combustion chamber casing and each tile is supported in position by a claimed supporting device.
Just to mention two different embodiments, the gas turbine may comprise in series a first combustion unit, a first turbine unit, a second combustion unit and a second turbine unit. Alternatively, the gas turbine may comprise a plurality of can combustor wherein each can combustor may be configured for producing two combustion stages in series.
Alternatively, a gas turbine according to the present invention may be a gas turbine having a single combustion stage, i.e. a gas turbine comprising in series a compressor, a combustor and a turbine.
It is to be understood that both the foregoing general description and the following detailed description are exemplary, and are intended to provide further explanation of the invention as claimed. Other advantages and features of the invention will be apparent from the following description, drawings and claims.
The features of the invention believed to be novel are set forth with particularity in the appended claims.

Brief description of drawings

Further benefits and advantages of the present invention will become apparent after a careful reading of the detailed description with appropriate reference to the accompanying drawings.
The invention itself, however, may be best understood by reference to the following detailed description of the invention, which describes an exemplary embodiment of the invention, taken in conjunction with the accompanying drawings, in which:

figure 1 is a schematic view of a first example of gas turbine assembly for power plants suitable for being provided with the present invention;
figure 2 is a schematic view of a second example of gas turbine assembly for power plants suitable for being provided with the present invention;
figure 3 discloses a combustion chamber tile supported in potion on the inner surface of a combustion chamber casing by a supporting device according to the prior art;
figure 4 discloses a first embodiment of a supporting device according to the invention, i.e. a supporting device according to figure 3 but provided with the new intermediate or spacing device;
figure 5 discloses a portion of the supporting device of figure 4 coupled to the combustor casing, in this figure the new cooling channels are represented;
figure 6 discloses two tiles respectively supported by a supporting device according to figure 3 (prior art) and a supporting device according to figure 4 (new);
figure 7 discloses a second embodiment of a supporting device according to the invention coupled to a tile;
figures 8 and 9 disclose the supporting device of figure 7 isolated from the tile;
figure 10-12 disclose some components of the supporting device of figures 9;
figure 13-14 disclose some components of a third embodiment of a supporting device according to the invention;
figure 15 discloses a fourth embodiment of a supporting device according to the invention;
figure 16 discloses an additional example of gas turbine assembly for power plants suitable for being provided with the present invention.

Detailed description of preferred embodiments of the invention

In cooperation with attached drawings, the technical contents and detailed description of the present invention are described thereinafter according to preferred embodiments, being not used to limit its executing scope.
Reference will now be made to the drawing figures to describe the present invention in detail.
Reference is now made to Fig. 1 that is a schematic view of a first example of a gas turbine 1 that can be improved with the present invention. In particular, figure 1 discloses a sequential gas turbine with a high pressure and a low pressure turbine. Following the main flow 2, the gas turbine 1 of figure 1 comprises a compressor 3, a first combustion stage, a high-pressure turbine 5, a second combustion stage and a low-pressure turbine 7. The compressor 3 and the two turbines 5, 7 are connected to a common rotor 8 rotating around an axis 9 and surrounded by a concentric casing 10. The compressor 3 is supplied with air and is provided with rotating blades 18 and stator vanes 19 configured for compressing the air entering the compressor 3. The compressed air leaving the compressor flows into a plenum 11 and from there into a plurality of first burners 12 where this compressed air is mixed with fuel supplied by a first fuel supply 13. The fuel/compressed air mixture flows into a first combustion chamber 4 where this mixture are ignited and combusted. The resulting hot gas leaves the first combustor chamber 4 and drives the high-pressure turbine 5 performing work on the rotor 8. Downstream of the high-pressure turbine 5 the gas partially expanded flows into a plurality of second burners where additional fuel is supplied by second fuel source 14. The partially expanded gas has a high temperature and contains sufficient oxygen for a further combustion that, based on a self-ignition, takes place in a second combustion chamber 6 arranged downstream the second burners. The reheated gas leaves the second combustion chamber 6 and flows in the low-pressure turbine 7 for performing rotating work on the rotor 8. The low-pressure turbine 7 comprises a plurality of stages, or rows, of rotor blades 15 arranged in series in the main flow direction. Such stages of blades 15 are interposed by stages of stator vanes 16. The rotor blades 15 are connected to the rotor 8 whereas the stator vanes 16 are connected to a vane carrier 17 that is a concentric casing surrounding the low-pressure turbine 7. Each burner of this example is configured for injecting different kinds of fuel, namely gas fuel and oil fuel, i.e. each burner comprises a plurality of nozzles configured for injecting gas fuel and connected to a gas fuel source and a plurality of nozzles configured for injecting oil fuel and connected to an oil fuel source.
Reference is now made to Fig. 2 that is a schematic view of a second example of a gas turbine 1 that can be improved with the present invention. In particular, figure 2 discloses a sequential gas turbine 20 provided with a compressor 29, an only a turbine 21 and a sequential combustor arrangement 22. The sequential combustor arrangement 22 of figure 2 comprises a plurality of can combustors wherein each can combustor comprises first burners 24, a first combustion chamber 25, a second burner 26, and a second combustion chamber 27. The first burner 24, the first combustion chamber 25, the second burner 26 and the second combustion chamber 27 are arranged sequentially in a fluid flow connection. The sequential combustor is housed in a combustor can casing 28 of a plurality of cans arranged as a ring around the turbine axis. A first fuel is introduced via a first fuel injector (not shown) into the first burner 24 wherein the fuel is mixed with the compressed gas supplied by the compressor 29. A second fuel is introduced into the second burner 26 via a second fuel injector (not shown) and mixed with hot gas leaving the first combustion chamber 25. The hot gas leaving the second combustion chamber 27 drives the turbine 21 performing work on a rotor 30.
The gas turbine of figure 1 and 2 have been cited only as example of gas turbines that can be improved by the present invention.
Figure 3 discloses a solution proposed by the prior art for solving the problem of supporting or keeping in position a tile of a combustion chamber. In particular, figure 3 discloses a portion of a combustion chamber casing 31 wherein the inner surface 32 of this casing 31 is provided with a plurality of grooves 33. The opposite surface 34 is in contact with cooling air. In figure 3 also a portion of a tile 35 is disclosed wherein this tile is coupled to the inner surface 32 of the casing 31 for thermally protecting the casing itself 31. Indeed, this tile 35 is made by a heat-insulating material, preferably a ceramic material. This tile 35 is supported in position on the inner surface 32 by a supporting device according to the prior art, i.e. a supporting device 36' comprising a plate 37 housed by sliding in a groove 33 and a hooked head 38 configured for being coupled to a groove 39 obtained in a side of the tile 35. This supporting device 36' is made of a metallic material and is cooled by air coming from holes 40 obtained in the casing 31. According this known solution the hooked head 38 comprises in series a first portion 41 orthogonal to the plate 37 protruding inside the combustion chamber and a second portion 42 orthogonal to the first 41 and parallel to the plate 37, wherein both the first 41 and the second portion 42 are in direct contact to the tile 35.
Figure 4 discloses a first embodiment of a supporting device according to the invention, i.e. a supporting device 36 according to figure 3 but provided with the new intermediate or spacing device 43. The intermediate or spacing device 43 of figure 4 comprises two spacing bodies 43 coupled to the first portion 41 of the hooked head 38 and spaced each other to realize a cooling channel 44 between them. Once coupled with the tile 35, the cooling channel 44 is limited by the first portion 41 of the hooked head 38, the tile 35 and the spacing bodies 43. The cooling air can enter this channel by a hole 45 obtained at the connection between the plate 37 and the hooked head 38.
Figure 5 discloses a portion of the supporting device 36 of figure 4 coupled to the combustor casing 31. In this figure the new cooling channel 44 is disclosed and the arrow F1 represents the cooling air flow entering the channel 41 by the hole 45. Once the air flow F1 reaches the second portion 42 of the hooked head 38, this air can flow in two lateral channels limited by the upper edges of the bodies 43 and the second portion 42 of the hooked head 38. In figure 5 these lateral flows are represented by the arrows F2.
Figure 6 discloses two tiles 35 respectively supported by a supporting device 36' according to figure 3 (prior art) and a supporting device 36 according to figure 4 (new) wherein the spacing device 43 is interposed between the first portion 41 of the hooked head 38 and the tile 35.
Figure 7 discloses a second embodiment of a supporting device 36 according to the invention coupled to a tile 35. As disclosed in figure 7, according to this embodiment the intermediate or spacing device 43' is also coupled to the second portion 42 of the hooked head 38 so that the tile 35 is in direct contact only with the intermediate or spacing device 43'.
Figure 8 and 9 disclose the supporting device 36 of figure 7 isolated from the tile 35. In this embodiment the intermediate or spacing device 43' is a single body spaced to the first portion 41 of the hooked head 38. As disclosed, in this embodiment the spacing device 43' comprises an opening 46 connected to the channel 44 and facing at one side the tile 35 and at the opposite side the first portion 41 of the hooked head 38.
Figures 10-12 disclose some components of the supporting device of figure 9. These figures allow to recognize that the channel 44 between the first portion 41 of the hooked head 38 and the spacing device 43' is obtained by a recessed portion 47 of the first portion 41 of the hooked head 38. According to this embodiment the spacing device 43' is coupled to the second portion 42 of the hooked head 38 by ribs 48 obtained in the upper part of the spacing device 43' housed in grooves 49 obtained in the second portion 42 of the hooked head 38.
Figure 13-14 disclose some components of an alternative embodiment similar to the embodiment of the previous figures. According to this last embodiment the spacing device 43' is coupled to the second portion 42 of the hooked head 38 by grooves 48' obtained in the upper part of the spacing device 43' housing ribs 49' obtained in the second portion 42 of the hooked head 38.
Figure 15 discloses an embodiment similar to the embodiment disclosed in figure 4 wherein the second portion 42 of the hooked head 38 is also provided with holes 50 for discharging the air from the channel 44 in order to prevent hot gas ingestion.
Finally, figure 16 discloses a schematic view of an additional example of a gas turbine 1' suitable for being provided with the present invention. Indeed, the present invention can be applied not only in gas turbines having two combustion stages a disclosed in figures 1 and 2 but also in a gas turbines having a single combustion stage regardless of the shape of the combustor unit. Therefore, figure 16 discloses a generic gas turbine 1' having a rotor 6' defining an axis 2'. This gas turbine 1' comprises in series along the main flow M:

a compressor 3',
a single combustor stage 4' wherein the compressed air is mixed with fuel and this mixture is combusted to create a hot gas flow,
a turbine section 5' where the hot gas flow expands performing rotating work on the rotor 6'.

According to figure 16, downstream the turbine 5' the rotor 6' drives the rotating part of a generator 7' . Although the invention has been explained in relation to its preferred embodiment(s) as mentioned above, it is to be understood that many other possible modifications and variations can be made without departing from the scope of the present invention, which is defined by the appended claims.

Claims

Supporting device (36) for supporting in position a heat-insulating tile (35) of a combustion chamber (31) of a gas turbine assembly for power plant; the supporting device (36) comprising:
- a plate (37) configured to be housed in a groove (33) obtained in an inner surface (32) of the combustion chamber (31) ;

- a hooked head (38) at an end of the plate (37) and configured to be coupled to a side of the tile (35), the hooked head (38) comprising in series a first portion (41) orthogonal to the plate (37) protruding inside the combustion chamber and a second portion (38) orthogonal to the first (41) and parallel to the plate (37);
characterized in that
the supporting device (36) moreover comprises at least an intermediate spacing device (43, 43') coupled to the hooked head (38) and configured for realizing a cooling channel (44) between the hooked head (38) and the tile (35).
Supporting device as claimed in claim 1, wherein the intermediate spacing device (43) comprises two bodies coupled to the first portion (41) of the hooked head (38), the two bodies are spaced each other for realizing a cooling channel (44) along the first portion (41) of the hooked head (38) .
Supporting device as claimed in claim 2, wherein the two bodies are coupled to the hooked head (38) so that to realize two cooling channels between the upper edges (43) of the bodies and the second portion (42) of the hooked head (38) at the connection between the first (41) and second portion (42) of the hooked head (38).
Supporting device as claimed in claim 1, wherein the intermediate spacing device (43') comprises a single body coupled to the first (41) and second portion (42) of the hooked head (38).
Supporting device as claimed in claim 4, wherein the single body is spaced from the first portion (41) of the hooked head (38).
Supporting device as claimed in claim 5, wherein the single body comprises an opening (46) facing the first portion (41) of the hooked head (38).
Supporting device as claimed in claim 5 or 6, wherein the single body is configured for realizing cooling channels between the body and the second portion (42) of the hooked head (38).
Supporting device as claimed in any one of the foregoing claims, wherein the hooked head (38) is T shaped.
Supporting device as claimed in any one of the foregoing claims, wherein at the connection between the first portion (41) and the second portion (42) of the hooked head (38) of the supporting device (36) is provided with at least a passing holes (45) connected to the cooling channel (44).
Gas turbine assembly (1') for power plant comprising a compressor unit (3'), at least a combustion unit (4') and at least a turbine unit (5'); the combustion unit comprises at least a combustion chamber defined by a casing (31) provided with a plurality of groves (33); a plurality of tile (35) are provided for heat-insulating the combustion chamber casing (31); each tile (35) is supported in position by a supporting device (36) as claimed in any one of the foregoing claims.
Gas turbine as claimed in claim 10, wherein the gas turbine comprises in series a first combustion unit (12), a first turbine unit (5), a second combustion unit (6) and a second turbine unit (7).
Gas turbine as claimed in claim 10, wherein the combustion unit comprises a plurality of can combustor (22); each can combustor being configured for producing two combustion stages in series.
Gas turbine as claimed in claim 10, wherein the gas turbine comprises a single combustor unit and a single turbine unit.