EP2644838A1 - Exhaust gas housing of a gas turbine - Google Patents

Abstract

The housing (9) has a cladding (12) enclosing a gas path (13) for guiding an exhaust gas flow of a gas turbine in a circumferential direction (14). A housing core (15) is arranged in the gas path, and struts (17) support the housing core at the cladding. The struts are distributedly arranged in the circumferential direction. The struts are rotatably adjusted in a longitudinal portion at a rotational axis (18), which extends parallel to a longitudinal direction of the struts. The housing core is designed as a bearing (16) for bearing a turbine rotor of the gas turbine. The struts are designed as profile struts. Independent claims are also included for the following: (1) a gas turbine system (2) a method for operating a gas turbine system.

Description

Technical area

The present invention relates to an exhaust gas housing for a gas turbine. The invention also relates to a gas turbine plant, in particular for driving a generator for generating electricity in a power plant, which is equipped with such an exhaust housing. The invention further relates to a method for operating such a gas turbine plant.

State of the art

A gas turbine plant, which is preferably used in a power plant for driving a generator for generating electricity, ie a stationary gas turbine plant, usually comprises a compressor for compressing a working gas, downstream of a combustion chamber for heating the working gas and downstream of a gas turbine for relaxing the working gas. The gas turbine has an exhaust gas outlet through which the expanded working gas, which is combustion exhaust gas of the combustion chamber, exits the gas turbine. From the exhaust gas outlet, the exhaust gas is supplied via a corresponding exhaust pipe, for example, an exhaust system or - in a combined cycle power plant - a steam generator for generating steam for operating a steam turbine. At the exhaust gas outlet of the gas turbine, the exhaust gas is subjected to a comparatively high swirl, which leads to a comparatively high flow resistance in the exhaust gas line. To reduce this flow resistance, an exhaust gas housing of the aforementioned type is used, which is arranged for this purpose on the exhaust gas outlet or on the input side to the exhaust pipe. Such an exhaust housing in this case comprises a jacket, which has a gas path for guiding an exhaust gas flow of the gas turbine in the circumferential direction encloses. Furthermore, within the shell and within the gas path, preferably centrally, a housing core is arranged, which is supported with a plurality of distributed in the circumferential direction arranged struts on the jacket. These struts can be designed as profile struts, which have a flow profile, which is employed with respect to the exhaust gas flow. In other words, the suitably radially arranged profile struts each have the same angle of attack with respect to the exhaust gas flow, which counteracts the twist and thus reduces the flow resistance in the subsequent exhaust pipe.

Appropriately, in this case the angle of attack of the profile struts is designed with respect to the base load of the gas turbine in order to achieve an optimal effect in terms of reducing the flow resistance in the exhaust pipe during the base load operation. The base load of the gas turbine corresponds to its nominal operating condition, for which it is energetically optimized.

However, it has been shown that gas turbine plants can not be operated continuously in the base load mode, but that comparatively often other operating conditions occur, such as peak loads, which require up to about 10% more power than in base load operation, or partial load operating conditions, the maximum 50% of Demand base load. Furthermore, any intermediate states as well as further, not mentioned here load states are conceivable. Since the exhaust housing is designed with respect to the angle of attack of the profile struts only on the base load of the gas turbine, the flow resistance in all deviating from the base load operating conditions are increased, which significantly reduces the energy efficiency of the gas turbine or the entire gas turbine plant in these other operating conditions.

Presentation of the invention

This is where the present invention begins. The invention deals with the task according to the problem, for an exhaust gas housing of the aforementioned type or for an equipped gas turbine plant or for an associated operating method to provide an improved embodiment, which is characterized in particular by the fact that even in operating conditions of the gas turbine plant, which differ from the base load, increased energy efficiencies can be achieved.

This problem is solved according to the invention by the subject matters of the independent claims. Advantageous embodiments are the subject of the dependent claims.

The invention is based on the general idea, at least one of the struts, by means of which the housing core is held in the jacket of the exhaust housing, with respect to their angle of attack relative to the exhaust gas flow to design adjustable. By this measure, it is possible to adjust the angle of the respective strut to different operating conditions of the gas turbine plant. Thus, in principle, an optimum angle of attack can be set for any desired operating state of the gas turbine plant. Thus, even for deviating from the base load load conditions of the gas turbine plant by adjusting the angle of attack of the respective strut, the flow resistance in the exhaust pipe can be reduced, which improves the energy efficiency of the gas turbine plant.

The respective strut is in this case along its entire length or only in a longitudinal section, that is not necessarily over its entire length, rotatable about a parallel to the longitudinal direction of the respective strut extending axis of rotation.

According to a particularly advantageous embodiment, the housing core of the exhaust housing may be designed as a bearing for supporting a rotor shaft of a turbine rotor of the gas turbine. By this measure, the exhaust housing is assigned a significant additional function, namely the bearing of the rotor shaft. In this way, the exhaust housing integrated in the scope of the gas turbine and thus forms part of a stator the gas turbine. The struts then serve to support the bearing on the mantle.

In an advantageous embodiment, at least one such strut, which is at least partially adjustable in rotation, can now have a strut core which connects the bearing or the aforementioned housing core to the strut core and a strut sheath which at least partially envelops the strut core and which is rotatable about the axis of rotation at least in a longitudinal section relative to the strut core is. In other words, the respective drehverstellbare strut has in this case a stationary strut core which connects the housing core or the bearing fixed to the mantle, and a mobile strut sheath which is rotatable about the axis of rotation with respect to the stationary strut core, in order in this way the Setting angle of rotation adjustable strut relative to the exhaust gas flow can. In this way, the exhaust management function is separated from the support function, which greatly simplifies the realization of a drehverstellbaren strut. In addition, since the strut sheath, which realizes the flow guide function, the strut core, which realizes the support function, the strut sheath decouples the strut core from the exhaust gas flow, whereby this is additionally protected and can be dimensioned accordingly compact.

Alternatively, it is also possible to design the respective rotationally adjustable strut in such a way that, at least in the rotationally adjustable longitudinal section, it can be rotated about the axis of rotation as a whole. In this case, the rotationally adjustable section has both the support function and the flow control function.

In another advantageous embodiment, the rotatable strut can be configured, at least in its rotationally adjustable range, as a profile strut having an airfoil. In the preferred embodiment described above, therefore, at least the strut sheave rotatable relative to the strut core is equipped with the flow profile. The flow profile is characterized by the fact that its profile length measured in the exhaust gas path in the flow direction of the exhaust gas is greater than its profile measured transversely thereto Profile thickness. By twisting the strut or the rotatable longitudinal section of the strut or the strut casing, the angle of attack of the profile strut relative to the exhaust gas flow can now be adjusted.

According to another advantageous embodiment, all struts that support the housing core or the bearing on the jacket, be designed to be adjustable in rotation.

Furthermore, the respective rotationally adjustable strut can be rotationally adjustable over its entire length. According to the preferred embodiment described above, therefore, the strut sheath can extend over the entire length of the strut.

The struts can be arranged in a star shape in the mantle. The housing core or the bearing may be held coaxially to the jacket via the struts in the jacket, wherein the jacket may in particular have a cylindrical cross-section.

According to another advantageous embodiment, at least one actuator for Drehverstellen at least one such drehverstellbaren strut may be provided. In principle, each rotary-adjustable strut can be associated with its own actuator, which then allows an individual rotational adjustability. Likewise, an embodiment is conceivable in which an actuator for driving at least two rotatable struts or for driving all rotatable struts is provided.

A gas turbine plant according to the invention, which serves in particular for driving a generator for generating electricity in a power plant, comprises at least one gas turbine for expanding combustion exhaust gas of a combustion chamber and an exhaust gas housing of the type described above, which is arranged on an exhaust gas outlet of the gas turbine. In this way, the exhaust-side flow resistance for different load conditions of the gas turbine plant can be reduced by changing the angle of attack of the struts. According to an advantageous embodiment, the gas turbine plant may have a control device for actuating or for controlling at least one actuator, which serves for Drehverstellen at least one of the rotationally adjustable struts. In this way, with the aid of the control device, the rotational position of the respective rotationally adjustable strut can be varied automatically depending on the operating state of the gas turbine or the gas turbine plant. It is clear that the control device for this purpose has knowledge of the current operating state of the gas turbine plant. In principle, a map-specific association between operating states of the gas turbine plant and suitable pitch angles of the adjustable struts is conceivable for this purpose.

An inventive method for operating a gas turbine plant is characterized in that depending on the current operating state of the gas turbine plant, a suitable rotational position of the respective rotationally adjustable strut is set.

The struts are preferably evenly distributed in the circumferential direction. However, it is also possible to provide a quasi-uniform distribution. If several adjustable struts are provided, these are expedient synchronously adjusted. In particular, the adjustable struts for their synchronous adjustment can be mechanically coupled together.

The flow profile can be conveniently designed symmetrical. A symmetrical flow profile is characterized by a mirror-symmetrical contour of the two outer sides of the respective airfoil with respect to a mirror axis, wherein the two outer sides of the airfoil begin at a common approach point and end at a common outflow point and wherein the approach point and the outflow point are both on the straight axis of symmetry.

Other important features and advantages of the invention will become apparent from the dependent claims, from the drawings and from the associated figure description with reference to the drawings.

It is understood that the features mentioned above and those yet to be explained below can be used not only in the particular combination given, but also in other combinations or in isolation, without departing from the scope of the present invention.

Brief description of the drawings

Preferred embodiments of the invention are illustrated in the drawings and will be described in more detail in the following description, wherein like reference numerals refer to the same or similar or functionally identical components.

Fig. 1

eine stark vereinfachte, schaltplanartige Prinzipdarstellung einer Gasturbinenanlage,

Fig. 2

eine stark vereinfachte isometrische Ansicht eines Abgasgehäuses,

Fig. 3

einen stark vereinfachten Querschnitt durch ein Strömungsprofil einer drehverstellbaren Strebe.

It show, each schematically

Fig. 1

a greatly simplified schematic diagram of a gas turbine plant,

Fig. 2

a greatly simplified isometric view of an exhaust housing,

Fig. 3

a greatly simplified cross section through a flow profile of a rotatable strut.

Description of embodiments of the invention

Corresponding Fig. 1 includes a gas turbine plant 1, which can be preferably used in a power plant for driving a generator for generating electricity, a compressor 2, according to an arrow 3, a working gas is fed and which serves to compress the working gas. The compressor 2 is followed by a combustion chamber 4, which is supplied according to an arrow 5 with compressed working gas and in which a fuel is reacted. According to an arrow 6, the compressed and heated working gas, which is now combustion exhaust gas of the combustion chamber 4, is fed to a gas turbine 7, in which the exhaust gas can be expanded. At an exhaust gas outlet 8 of the gas turbine 7, an exhaust housing 9 is arranged, which is flowed through by the exhaust gas of the gas turbine 7, before the exhaust gas passes according to an arrow 10 in an exhaust pipe not shown here. The gas turbine plant 1 expediently comprises a rotor 11 which forms a compressor rotor in the region of the compressor 2 and a turbine rotor in the region of the gas turbine 7, which may also be designated 11 below.

Corresponding Fig. 2 the exhaust housing 9 comprises a jacket 12 having an in Fig. 2 surrounded by arrows indicated gas path 13 in the circumferential direction, the in Fig. 2 indicated by a double arrow and denoted by 14. The gas path 13 serves to guide the exhaust gas flow of the gas turbine 7, which emerges from the gas turbine 7 at the exhaust gas outlet 8. Furthermore, the exhaust housing 9 comprises a housing core 15, which is arranged in the gas path 13. Preferably, this housing core 15 is designed as a bearing 16, by means of which the turbine rotor 11 can be mounted on the exhaust housing 9. The housing core 15 or the bearing 16 is supported on the casing 12 with a plurality of struts 17. The struts 17 are arranged distributed in the circumferential direction 14, preferably uniformly, however, a quasi-uniform distribution is also possible, which can be used to special flow conditions. Further, the central positioning of the bearing 16 shown here is concentric in the cylindrical shell 12 is preferred, resulting in the struts 17, the star-shaped arrangement shown here. In the example of Fig. 2 are shown without limitation of generality, only four struts 17. It is clear that in principle less or more than four struts 17 can be used to support the housing core 15 and the bearing 16 on the casing 12. At least one of the struts 17 is designed to be rotationally adjustable in at least one longitudinal section about an axis of rotation 18. In the example of Fig. 2 are all struts 17 each along its entire length about such a rotation axis 18 relative to the housing core 15 and the bearing 16 and with respect to the jacket 12 rotatably adjustable. The respective axis of rotation 18 extends parallel to the longitudinal direction of the respective strut 17. The struts 17 extend radially with respect to a longitudinal central axis 19 of the shell 12. Alternatively, it can also be provided that only a substantial longitudinal section of the respective strut 17 is designed to be adjustable in rotation.

In principle, the respective strut 17 can be rotationally adjustable relative to the casing 12 or relative to the casing core 15 or bearing 16.

Fig. 3 shows a modified embodiment in which the respective rotatable strut 17 has a strut core 20 and the strut core 20 enveloping strut sheath 21. The strut core 20 is used for firmly connecting the housing core 15 and the bearing 16 with the casing 12. The respective strut core 20 is thus stationary and not rotationally adjustable. In contrast, the respective strut sheath 21 is at least in a longitudinal section relative to the strut core 20 about the aforementioned rotation axis 18 rotatable. In this way, the respective strut core 20 keeps the housing core 15 stably positioned in the casing 12, while the strut casing 21 fulfills a flow guiding function.

Regardless of whether the respective drehverstellbare strut 17 now according to Fig. 3 has a strut core 20 and a strut casing 21 or is relatively adjustable in rotation relative to the casing 12, the respective strut is according to Fig. 3 preferably configured as a profile strut, which is characterized by a flow profile 22 at least in its rotationally adjustable range. The airfoil 22 has a profile beginning at an inflow point 23 of the airfoil 22 and ending at an outflow point 24 of the airfoil 22 profile length 25 and a transverse thereto measured profile thickness 26. The profile length 25 is greater than the profile thickness 26 in the airfoil profile Profile length 25 about twice as large as the profile thickness 26. It is clear that others Ratios of profile length to profile thickness are conceivable. Fig. 2 For example, it shows a ratio of at least 4: 1.

By turning the strut 17 can now be an angle α against the in Fig. 3 be indicated by an arrow indicated exhaust flow 27. The angle of attack α is also in Fig. 2 indicated. In Fig. 2 Turning arrows 28 also indicate the rotational adjustability of all struts 17.

According to Fig. 2 At least one actuator 29 may be provided, by means of which at least one of the struts 17 can be driven to Drehverstellen. A corresponding drive coupling is in Fig. 2 indicated by a double arrow 30. The actuator 29 may be suitably arranged outside on the jacket 12. In principle, each rotationally adjustable strut 17 can be assigned its own such actuator 29. Conveniently, however, is a mechanical positive coupling of the adjustable struts 19, so that a single actuator 29 is sufficient to several or preferably to drive all the rotatable struts 17 synchronously. For actuating or for driving the respective actuator 29 is in Fig. 2 In addition, a control device 31 indicated, which is coupled via a corresponding control connection 32 with the respective actuator 29. The control device 31 can now be suitably configured or programmed such that it operates the gas turbine plant 1 according to an operating method in which, depending on the current operating state of the gas turbine plant 1 a suitable rotational position, ie an angle α for the respective drehverstellbare strut 17 and determined the respective actuator 29 is set. Thus, the flow resistance of the exhaust gas flow of the gas turbine 7 in an exhaust pipe can be optimized even with varying load conditions of the gas turbine plant 1.

LIST OF REFERENCE NUMBERS

1

Gas turbine plant

2

compressor

3

arrow

4

combustion chamber

5

arrow

6

arrow

7

gas turbine

8th

exhaust outlet

9

exhaust housing

10

arrow

11

rotor

12

coat

13

gas path

14

circumferentially

15

housing core

16

camp

17

strut

18

axis of rotation

19

Longitudinal central axis of 12

20

truss core

21

pursuit Case

22

flow profile

23

Anströmpunkt

24

Abströmpunkt

25

Section length

26

profile thickness

27

exhaust gas flow

28

rotation arrow

29

actuator

30

drive coupling

31

control device

32

control connection

Claims (10)

Exhaust casing of a gas turbine (7), - With a jacket (12) which encloses a gas path (13) for guiding an exhaust gas flow (27) of the gas turbine (7) in the circumferential direction (14), with a housing core (15) arranged in the gas path (13), - with a plurality of struts (17) for supporting the housing core (15) on the jacket (12), which are arranged distributed in the circumferential direction (14), - Wherein at least one such strut (17) in at least one longitudinal section about a parallel to the longitudinal direction of the respective strut (17) extending axis of rotation (18) is rotatably adjustable. Exhaust housing according to claim 1, characterized in that the housing core (15) as a bearing (16) for supporting a turbine rotor (11) of the gas turbine (7) is configured. Exhaust housing according to claim 1 or 2, characterized in that at least one such drehverstellbare strut (17) a housing core (15) fixedly connected to the jacket (12) strut core (20) and a strut core (20) at least partially enveloping strut sheath (21 ), which is rotatable about the axis of rotation (18) at least in a longitudinal section relative to the strut core (20). Exhaust housing according to one of claims 1 to 3, characterized in that the drehverstellbare strut (17) is designed at least in its drehverstellbaren area as a profile strut having a flow profile (22). Exhaust housing according to one of claims 1 to 4, characterized in that the respective strut (17) is rotationally adjustable over its entire or quasi-complete length or partial length. Exhaust housing according to one of claims 1 to 5, characterized in that all struts (17) are configured uniformly or individually adjustable in rotation. Exhaust housing according to one of claims 1 to 6, characterized by at least one actuator (29) for Drehverstellen at least one such rotatable strut (17). Gas turbine plant, in particular for driving a generator for generating electricity in a power plant, with a gas turbine (7) for relaxing combustion exhaust gas of a combustion chamber (4), - With an exhaust housing (9) according to one of claims 1 to 7, which is arranged on an exhaust gas outlet (8) of the gas turbine (7). Gas turbine plant according to claim 8, characterized by a control device (31) for actuating at least one actuator (29) according to claim 7 for varying the rotational position of the respective rotatable strut (17) depending on the operating state of the gas turbine plant (1). Method for operating a gas turbine plant (1) according to Claim 8 or 9, in which, depending on the current operating state of the gas turbine plant (1), a rotational position of the respective rotationally adjustable strut (17) is set.

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