EP2317227A2 - Burner for a turbine and gas turbine with same - Google Patents

Abstract

The burner has a housing (10), in which an air collection chamber (13), a combustion antechamber (16) and a combustion chamber are formed. A burner-head plate (40) is arranged in the housing so that the burner-head plate separates the combustion antechamber from the combustion chamber. A bulging plate (30) is arranged in the combustion antechamber and has multiple through passages (31).

Description

The invention relates to a burner for a turbine and a gas turbine equipped with such a burner,

Various burners for atmospheric combustion and combustion under pressure are known. Also in the field of gas turbines, various such burners are used,

Examples of burners of gas turbines are in DE 10 2006 048 842 A1 . DE 195 42 521 A1 . DE 43 28 294 A1 . DE 195 49 143 A1 . WO 96/04510 and in the Magazine "ABB Technik" from 4/1998 on pages 4 to 16 described.

A major aim of such burners is to make combustion in a large operating range stable, controlled, low in pollutants and as complete as possible. In certain burners, special components are used as "flame holders" to stabilize the combustion zone (zone of heat release). Other burners are designed so that the stabilization near the wall - z, B. in the center of the burner - takes place. These components are thermally highly loaded, have a short life and must therefore be replaced often.

In order not to impair the stability of the combustion or to escape the process no cooling air, these components are not cooled according to the prior art, Thus, the inspection and maintenance intervals for these components are correspondingly short, which together with the downtime of the respective system additional, high costs.

The invention has for its object to provide a burner for a turbine, in particular for a gas turbine, in which the central component or, the flame holder can be effectively cooled without disturbing the combustion process in the burner. A further object of the invention is to provide a gas turbine equipped with such a burner,

The o.g. Problems are solved with a burner according to claim 1 or a gas turbine according to claim 14. Further developments of the invention are defined in the dependent claims,

According to a first aspect of the invention, there is provided a burner for a turbine, in particular a gas turbine, the burner comprising: a housing in which an air collecting space, a combustion pre-space and a combustion space are formed, a burner top plate arranged in the housing is, so that the burner head plate separates the combustion antechamber from the combustion chamber, a baffle plate which is arranged in the combustion antechamber, so that the baffle plate, the combustion antechamber in an adjacent to an air-collecting space with the air supply air-connected first subspace and one to the burner top plate subdivided adjacent second subspace, wherein the baffle plate has a plurality of passage passages, which fluidly connect the first subspace with the second subspace, so that inflow via the air supply from the air collecting space in the first subspace inflowed air via the passage passages in the second subspace and on a thesecond subspace facing rear surface of the burner top plate can flow.

With the solution according to the invention, since cooling air is applied to the rear surface of the burner top plate so that efficient impingement cooling for the burner top plate is achieved, the burner top plate can be effectively achieved cooled and thus their thermal wear can be reduced, the inventively proposed cooling thus significantly increases the life of the burner top plate. Since only the back of the burner top plate is charged with the cooling air, wherein the air is preferably supplied to an outer edge of the burner top plate to the combustion chamber, the air or cooling exerts no disturbing effect on the combustion process in the burner.

According to one embodiment of the burner according to the invention, the baffle plate extends parallel to the burner top plate, so that air which has flowed into the second partial space impinges perpendicularly on the rear surface of the burner top plate.

According to a further embodiment of the burner according to the invention, a gap is provided on the outer circumference of the burner head plate, via which the second subspace is fluidly connected to the combustion chamber, so that air rebounding from the rear face of the burner head plate can flow out into the combustion chamber via the gap.

The cooling air can therefore not be introduced into the combustion chamber outside the edge of the burner top plate and thus the combustion process by the gap, as a result of which the air is retained in the overall process (burner, turbine).

According to the invention, the injection of the cooling air should, as far as possible, take place "outside", away from a mean recirculation flow of the burner, thus ensuring that a core zone of the recirculation flow is not disturbed.

According to yet another embodiment of the burner according to the invention, the second subspace is bounded on the outside by an insertion part, wherein in a turn of the insert part is provided an opening extending perpendicular to the passage passages, which fluidly connects the second subspace with the gap, so that air rebounding from the rear surface of the burner head plate can flow out into the gap via the opening.

On the one hand, the cooling air can be routed through this opening, as required, transversely to the outer edge of the burner top plate or the combustion chamber so that its influence on the combustion is minimized, and, on the other hand, the air flow can be specifically influenced by its diameter.

According to yet another embodiment of the burner according to the invention, the gap is formed as an annular gap, wherein in the turn of the insert part a plurality of perpendicular to the passage passages extending along a circumference of the gap distributed openings are provided, which fluidly connect the second subspace with the gap, so that rebounding air from the rear surface of the burner top plate can flow out through the openings into the gap.

By forming the gap as an annular gap and by providing the circumferentially distributed plurality of openings, the air after cooling the burner top plate can be extremely evenly distributed in the combustion chamber, so that their influence on the combustion is further minimized.

According to a further embodiment of the burner according to the invention, the gap extends parallel to the passage passages, so that a flow direction of the air through the gap is parallel to a flow direction of the air through the passage passages

According to yet another embodiment of the inventive burner, a width of the gap is dimensioned such that a flow velocity of the Air at the exit from the gap is less than a flow velocity of the air entering the gap.

In other words, the width of the gap should be as large as possible to minimize the flow velocity of the air and thus its penetration into a main flow of combustion, which in turn ensures that the main flow is influenced as little as possible.

According to one embodiment of the burner according to the invention, a plurality of passage openings are provided in the burner head plate, which fluidly connect the second subspace to the combustion chamber.

This represents a further possibility of removing the airflow preferably without influencing the combustion, preferably at the outer edge of the burner top plate or the combustion chamber and using the air flow for the overall process after cooling,

According to a further embodiment of the burner according to the invention, the through-openings each have a diameter in a range from 0.3 mm to 1.5 mm, so that the through-holes an effusion of the air flowed through the passage passages in the second sub-chamber through the burner head plate into the combustion chamber,

This embodiment of the invention advantageously supports both the cooling efficiency and the freedom from influencing the cooling air flow.

According to yet another embodiment of the burner according to the invention, the burner top plate is formed by a porous material, so that in the second Subspace inflowed air can flow through pores of the burner head plate into the combustion chamber.

Also, this embodiment of the invention provides an advantageous possibility to dissipate the cooling air flow as possible without affecting the combustion and with continued use of the air flow for the entire process after cooling.

According to a further embodiment of the burner according to the invention, an air discharge passage is provided in the second subspace, via which air rebounding from the rear face of the burner head plate can be fed into the combustion chamber downstream of the burner head plate with respect to a combustion process in the combustion chamber.

In other words, external cooling is used here, the removal of the cooling air being described in connection with the other embodiments of the invention or at another location between e.g. a compressor outlet and the air collection chamber takes place. After cooling, the air is not injected directly into the combustion chamber, but derived. The air is thus not immediately after the swirl body, but at a subsequent position-downstream of the hot gas of the combustion considered- initiated, possible positions for the introduction of the air are in the range of a secondary zone of the combustion chamber to an exhaust stack of the gas turbine.

The advantage of these solutions is that an influence of the main flow and thus the combustion is excluded by the cooling air flow. In addition, the usable pressure gradient increases and thus a greater temperature reduction can be achieved. The disadvantage of the solution is that the air can only partially or not at all be used for the gas turbine process,

According to a second aspect of the invention, a gas turbine with a burner according to one, several or all of the previously described embodiments of the invention is provided in any conceivable combination.

Fig. 1

zeigt den üblichen Aufbau eines Brenners für eine Turbine wie eine Gasturbine.

Fig.2

zeigt in vergrößerter Ansicht einen Bereich X aus Fig. 1, wobei der Brenner mit einer erfindungsgemäßen internen Kühlung für die Brenner-Kopfplatte ausgerüstet ist.

In the following the invention will be described in more detail by means of preferred embodiments and with reference to the attached figures.

Fig. 1

shows the usual construction of a burner for a turbine such as a gas turbine.

Fig.2

shows an area X in an enlarged view Fig. 1 wherein the burner is equipped with an internal cooling according to the invention for the burner top plate.

As in Fig. 1 and Fig.2 1, a burner 1 of a gas turbine (not completely shown) according to an embodiment of the invention, a housing 10, which in turn has a flame tube 11, in which the combustion V of an air-fuel gas mixture takes place, and a jacket 12, the softer Flame tube 11 surrounds. Between the flame tube 11 and the shell 12, an air collecting space 13 is formed, softer called plenum and softer frontally bounded by a burner cap 70, in the flame tube, a combustion chamber 14 is formed, which is provided for the combustion V of the air-fuel gas mixture ,

The housing 10 further has a mixing part 15, via which the air-fuel gas mixture for combustion V in the combustion chamber 14 is provided. In the mixing part 15, a combustion apron 16 is formed.

The burner 1 further comprises a plate-shaped central cover 20, a baffle plate 30 and a burner top plate 40 which in the mixing part 15 of the housing 10th are arranged. More precisely, the central cover 20 forms an inlet for cooling air K provided for cooling the burner top plate 40. The burner 1 furthermore has a swirl body or mixing body 80, via which the air-fuel gas mixture is arranged laterally or externally in the combustion chamber 14 for the combustion V is generated.

For this purpose, the air plenum 13 (plenum) is fluidly connected to air inlet openings 22 in the central cover 20 via supply elements 21 (such as pipes, for example), control means 21 a being e.g. are provided in the form of air valves, so that the partial air mass flow flowing from the air collecting space 13 through the supply elements 21 can be controlled.

In a flow direction of the cooling air K downstream of the central cover 20, the baffle plate 30 is arranged in the combustion antechamber 16 parallel to this. Between the central cover 20 and the baffle plate 30, a first subspace 16a of the combustion antechamber 16 is formed in the form of a Zwischenplenums.

In a flow direction of the cooling air K downstream of the baffle plate 30, the burner top plate 40 is arranged parallel to this in the combustion chamber 16, between the baffle plate 30 and the burner top plate 40, a second subspace 16 b of the combustion vestibule 16 is formed,

In other words, the baffle plate 30 is disposed in the combustion vestibule 16 so as to divide the combustion vestibule 16 into the first partial space 16a adjoining the supply elements 21 fluidly connected to the air collecting space 13 and the second partial space 16b adjoining the burner top plate 40.

The burner top plate 20 is disposed in the combustion vestibule 16 of the housing 10 so as to separate the combustion vestibule 16 from the combustion chamber 14, and forms a central component of the burner 1.

A symmetrical removal of the partial air mass flow from the air collection chamber 13, such as e.g. By means of several supply elements 21, ensures both a homogeneous removal and a homogeneous inflow of cooling air K in the first compartment 16a, the first compartment 16a (Zwischenplenum) is designed so that the cooling air K evenly distributed and the baffle plate (such as a Baffle plate) 30 is supplied evenly with cooling air K.

The baffle plate 30 has a plurality of passage passages 31, which fluidly connect the first subspace 16a with the second subspace 16b, so that via the feed elements (air supply) 21 from the air collecting space 13 in the first subspace 16a flowing cooling air K via the passage passages 31 in the flow in second subspace 16b and on a second subspace 16b facing the rear surface 40a of the burner top plate 40 can flow.

The baffle 30 extends parallel to the burner top plate 40, so that the cooling air K, which has flowed into the second compartment 16 b, impinges substantially perpendicularly on the back surface 40 a of the burner top plate 40.

The second subspace 16b is bounded on the outside by an insertion part 50, wherein a plurality of openings 51 extending perpendicularly to the passage passages 31 are provided in a wall of the insertion part 50. Outside the insert part, a jacket part 60 is provided which limits the mixing part 15 on the outside. The jacket part 60 is in turn inserted into the burner chamber 70 which closes or delimits the air collecting space 13 and is held by the latter.

Between the insertion part 50 and the shell part 60 and the outer circumference of the burner top plate 40, a gap S is provided in the form of an annular gap, via which the second compartment 16b is fluidly connected to the combustion chamber 14, so that rebounding from the rear surface 40a of the burner top plate 40 Cooling air K can flow through the gap in the combustion chamber 14.

More specifically, the second subspace 16b is fluidly connected to the gap S via the openings 51 distributed along a circumference of the gap S, so that cooling air K bouncing off the rear surface 40a of the burner top plate 40 can flow into the gap S via the openings 51.

The gap S extends parallel to the through passages 31 and opens into the combustion chamber 14, so that a flow direction of the cooling air K through the gap S is parallel to a flow direction of the cooling air K through the passage passages 31 therethrough.

In conclusion, after the cooling air jets of the flame holding plate 40 generated via the through passages 31 have extracted heat, the cooling air K is discharged via the lateral openings 51, which are preferably designed as bores, into the gap S and from there into the combustion chamber 14.

The efficiency of the impingement cooling can be varied by the choice of the perforation in the baffle plate 30 and the pressure loss (individual pressure losses of the cooling air line). The driving pressure gradient is essentially predetermined by the pressure loss of a main air mass flow (for the combustion process) through the swirler 80.

As already mentioned, the heat load in the center of the burner top plate or burner plate 40 is highest, wherein in accordance with the invention realized cooling the center of the burner top plate 40 is cooled most efficiently. As the diameter increases, cross-flow increases and cooling efficiency decreases. In this respect, the proposed cooling fits the impressed hot gas side or combustion chamber side thermal load of the burner top plate 40.

According to the invention, it has been recognized that the injection of the cooling air K should be as "outside" as possible, away from a mean recirculation flow RS of the burner 1, thus ensuring that a core zone of the recirculation flow RS is not disturbed. Furthermore, it has been recognized according to the invention that it is also important to keep the momentum of the cooling air K as low as possible when entering the combustion chamber 14, thus preventing too great a penetration depth of the cooling air flow into the main flow related to the combustion V and thus the main flow is so little is influenced as possible.

To meet these requirements, a diameter D (see Fig.2 ) are chosen as large as possible for the introduction of the cooling air K into the combustion chamber 14 and can preferably result according to the specification D (> 1 / 2d), where d is a diameter of the burner top plate 40. In other words, a width of the gap S should be as large as possible and the gap S should be arranged as far as possible radially outward with respect to the burner top plate 40. The width of the gap S defined by the jacket part 60 and the insert part 50 is preferably dimensioned such that a flow velocity of the cooling air K at the exit from the gap S into the combustion chamber 14 is less than a flow velocity of the cooling air when entering the gap S. ,

In summary, the inventively realized cooling of the burner top plate 40 is based on an impingement cooling, which cools the burner top plate 40 as a central component of the burner 1 very efficiently. By a suitable choice of Kühltufteindüsung the edge of the burner top plate 40, the combustion process is not adversely affected. In addition, according to the shown in the figures Embodiment of the invention, the cooling air K remain the overall process (as a variant also described below external removal of the cooling air K is possible). The pressure loss via the burner or burners 1 of the gas turbine serves as a criterion for the cooling.

In addition, in the proposed solution, valves can be easily implemented to optimize cooling or the amount of cooling air, e.g. the control means 21a.

Although in the FIGS. 1 and 2 not shown, may alternatively or in addition to the gap S and the openings 51 in the burner top plate 40 itself a plurality of through holes may be provided, which fluidly connect the second subspace 16b respectively with the combustion chamber 14.

In this way, the cooling air K which has flowed into the second subspace 16b via the through passages 31 can then be removed from the second subspace 16b into the combustion chamber 14 directly via the burner head plate 40.

According to a preferred variant, these passage openings may each have a diameter in a range from 0.3 mm to 1.5 mm, so that the passage openings cause an effusion of the cooling air K, which has flowed into the second subspace 16b via the passage passages 31, through the burner head plate 40 through into the combustion chamber 14 into effect.

As an alternative to the passage openings, the burner top plate 40 may be formed by a porous material, so that cooling air K which has flowed into the second subspace 16b can flow out into the combustion chamber 14 via pores of the burner top plate 40.

In each of these cases, the cooling air K is returned to the primary combustion process.

Alternatively, although not in the FIGS. 1 and 2 2, an air discharge passage may be provided in the second subspace 16b through which cooling air K rebounding from the rear face 40a of the burner top plate 40 is fed downstream of the burner head plate 40 remote from the combustion process in the combustion chamber 14 with respect to the combustion process.

In other words, an external cooling is used here, wherein the removal of the cooling air K as described above in connection with the other embodiments of the invention or takes place at another location between, for example, a compressor outlet and the air collection chamber 13. After cooling, the cooling air K is not injected directly into the combustion chamber 14, but derived. The cooling air K is thus not immediately after the swirl body 80, but at a following position -stromab in the flow direction of the hot gas combustion V considered- initiated. Possible positions for the introduction of the cooling air K are in the range of a secondary zone of the combustion chamber 14 up to an exhaust stack of the gas turbine.

The advantage of these solutions is that an influence of the main flow and thus the combustion V is excluded by the cooling air flow. In addition, the usable pressure gradient of the cooling increases and thus a greater temperature reduction can be achieved. The disadvantage of the solution is that the cooling air K can only partially or not at all be used for the gas turbine process.

LIST OF REFERENCE NUMBERS

1

burner

10

casing

11

flame tube

12

coat

13

Air plenum

14

combustion chamber

15

mixing section

16

Verbrennungsvorraum

16a

first subspace

16b

second subspace

20

Central cover

21

supplying member

21a

control means

22

Lufteinfassöffnungen

30

flapper

31

Through passages

40

Burner head plate

40a

rear surface

50

insert

51

opening

60

jacket part

70

burner caps

80

swirler

S

gap

V

combustion

K

cooling air

RS

recirculation

Claims (14)

Burner (1) for a turbine, comprising: a housing (10) in which an air collecting space (13), a combustion antechamber (16) and a combustion chamber (14) are formed, a burner head plate (40) disposed in the housing (10) such that the burner head plate (40) separates the combustion antechamber (16) from the combustion chamber (14), a baffle plate (30) disposed in the combustion antechamber (16). such that the baffle plate (30) subdivides the combustion antechamber (16) into a first subspace (16a) adjacent to an air feed line fluidly connected to the air collecting space (13) and a second subspace (16b) adjoining the burner head plate (40), wherein the baffle plate (30) comprises a plurality of through passages (31) fluidly connecting the first subspace (16a) to the second subspace (16b) so as to flow into the first subspace (16a) via the air supply from the air collection space (13) Air via the passage passages (31) in the second subspace (16b) flow and on a second subspace (16b) facing the rear surface (40a) of the burner head plate (40) can flow. A burner (1) according to claim 1, wherein the baffle plate (30) extends parallel to the burner top plate (40) such that air flowed into the second subspace (16b) is perpendicular to the back surface (40a) of the burner top plate (40) ). Burner (1) according to claim 1 or 2, wherein outside the burner head plate (40) a gap (S) is provided, via which the second subspace (16b) is fluidly connected to the combustion chamber (14), so that from the rear surface ( 40a) of the burner head plate (40) can bounce off rebounding air through the gap (S) in the combustion chamber (14). A burner (1) according to claim 3, wherein the second compartment (16b) is circumferentially bounded by an insert member (50), and wherein an opening (51) extending perpendicular to the passageways (31) is provided in a wall of the insert member (50) which fluidly connects the second subspace (16b) with the gap (S) so that air rebounding from the rear surface (40a) of the burner head plate (40) can flow out into the gap (S) via the opening (51). Burner (1) according to claim 4, wherein the gap (S) is formed as an annular gap, and wherein in the wall of the insert (50) a plurality of perpendicular to the passage passages (31) extending along a circumference of the gap (S) distributed Openings (51) are provided which fluidly connect the second subspace (16b) to the gap (S), so that air rebounding from the rear face (40a) of the burner head plate (40) via the openings (51) into the gap (51). S) can flow out. Burner (1) according to one of claims 3 to 5, wherein the gap (S) extends parallel to the through passages (31), so that a flow direction of the air through the gap (S) parallel to a flow direction of the air through passages ( 31) is through. Burner (1) according to one of claims 3 to 6, wherein a width of the gap (S) is dimensioned such that a flow velocity of the air exiting the gap (S) into the combustion chamber (14) is less than a flow velocity of the air Entry into the gap (S) is. Burner (1) according to one of claims 1 to 7, wherein in the burner top plate (40) a plurality of passage openings are provided, which fluidly connect the second partial space (16b) with the combustion chamber (14). Burner (1) according to claim 8, wherein the through-openings each have a diameter in a range of 0.3 mm to 1.5 mm, so that the through-holes have an effusion of the over the passageways (31) into the second sub-space (31) Air through the burner head plate (40) through into the combustion chamber (14) into it. Burner (1) according to one of claims 1 to 7, wherein the burner head plate (40) is formed of a porous material, so that in the second subspace (16b) air flowed through pores of the burner head plate (40) into the combustion chamber (14) can flow into it. Burner (1) according to one of claims 1 to 7, wherein in the second subspace (16b) an air discharge passage is provided, via the rebounding from the rear surface (40a) of the burner top plate (40) air with respect to a combustion process in the combustion chamber ( 14) downstream of the burner top plate (40) can be fed, Burner (1) according to claim 11, wherein the air discharge passage opens into a secondary zone of the combustion chamber (14). Burner 1 according to claim 11, wherein the air discharge passage opens into an exhaust stack of the burner (1). Gas turbine with a burner (1) according to one of claims 1 to 13.

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