Combustor arrangement with slidable multi-cone premix burner

Abstract

A combustor arrangement includes a combustion chamber with a front panel, and a premix burner of the multi-cone type, which is connected to the front panel through an elongated mixing zone in an axially moveable fashion by a sealed sliding joint. A wide range of axial variation of the burner with a minimized influence of the leakage air flow on the oxidation process within the flame is achieved by positioning the sealed sliding joint upstream of the mixing zone.

Claims

1. A combustor arrangement, comprising: a combustion chamber with a front panel, and a premix burner of a multi-cone type, which is connected to said front panel through an elongated mixing zone in an axially moveable fashion by a sealed slidable joint, wherein said sealed slidable joint is positioned upstream of said mixing zone, wherein the sealed slidable joint is made up by a coaxial sliding arrangement of a cylindrical burner ring and an essentially cylindrical burner sleeve, the essentially cylindrical burner sleeve defining an axial direction and a radial direction perpendicular to said axial direction, wherein said burner ring is fixed to said premix burner and said burner sleeve is fixed to and part of said front panel, and a seal is located between said burner ring and said burner sleeve in the radial direction, and wherein the seal is arranged to be slidable, in the axial direction, along and against a surface of the burner ring or the burner sleeve during relative movement of the burner ring and the burner sleeve such that the entirety of the seal is located within the essentially cylindrical burner in the radial direction and circumferentially surrounds the burner ring.

2. The combustor arrangement according to claim 1, wherein said burner ring is surrounded by said burner sleeve.

3. The combustor arrangement according to claim 2, wherein said burner ring extends upstream of the downstream end of the burner, and the seal is positioned at the upstream end of the burner ring.

4. The combustor arrangement according to claim 1, wherein the burner sleeve has a conically widening burner outlet at the transition to said combustion chamber.

5. The combustor arrangement according to claim 3, wherein the burner sleeve includes purge air holes downstream of the seal to purge the gap between burner ring and burner sleeve with air.

6. The combustor arrangement according to claim 1, wherein said premix burner comprises: a plurality of burner shells, which are arranged around a central burner axis and are parts of a virtual, axially extending common cone, which opens in a downstream direction, and wherein said parts are displaced perpendicular to said burner axis such that a tangential slot is defined between each pair of adjacent shells, and wherein each of the shells is equipped with a premix gas channel extending along an axially oriented edge of the respective shell such that a gas can be injected from said premix gas channel through gas injection holes into a stream of air entering the interior of the arrangement of shells through the adjacent slot, and wherein the downstream ends of the shells and premix gas channels are bordered by intersecting planes, which are defined by intersecting said shells and premix gas channels with a virtual coaxial cylinder of a predetermined radius, and wherein said burner ring has an inner radius similar to said predetermined radius.

7. A combustor arrangement, comprising: a combustion chamber with a front panel; and a premix burner of a multi-cone type, which is connected to said front panel through an elongated mixing zone in an axially moveable fashion by a sealed slidable joint; wherein said sealed slidable joint is positioned upstream of said mixing zone; wherein the sealed slidable joint is made up by a coaxial sliding arrangement of a cylindrical burner ring and an essentially cylindrical burner sleeve; wherein said burner ring is fixed to said premix burner and said burner sleeve is fixed to and part of said front panel, and a seal is provided between said burner ring and said burner sleeve; and wherein the seal, the burner ring and the burner sleeve are arranged and configured such that the seal axially will slide along and against a surface of the burner ring or the burner sleeve during any axial relative movement of the burner ring and the burner sleeve such that the seal is located on a radially inner surface of the essentially cylindrical burner and on a radially outer surface of the burner ring.

8. The combustor arrangement according to claim 7, wherein said burner ring is surrounded by said burner sleeve.

9. The combustor arrangement according to claim 8, wherein said burner ring extends upstream of the downstream end of the burner, and the seal is positioned at the upstream end of the burner ring.

10. The combustor arrangement according to claim 7, wherein the burner sleeve has a conically widening burner outlet at the transition to said combustion chamber.

11. The combustor arrangement according to claim 9, wherein the burner sleeve includes purge air holes downstream of the seal to purge the gap between burner ring and burner sleeve with air.

12. The combustor arrangement according to claim 7, wherein said premix burner comprises: a plurality of burner shells, which are arranged around a central burner axis and are parts of a virtual, axially extending common cone, which opens in a downstream direction, and wherein said parts are displaced perpendicular to said burner axis such that a tangential slot is defined between each pair of adjacent shells, and wherein each of the shells is equipped with a premix gas channel extending along an axially oriented edge of the respective shell such that a gas can be injected from said premix gas channel through gas injection holes into a stream of air entering the interior of the arrangement of shells through the adjacent slot, and wherein the downstream ends of the shells and premix gas channels are bordered by intersecting planes, which are defined by intersecting said shells and premix gas channels with a virtual coaxial cylinder of a predetermined radius, and wherein said burner ring has an inner radius similar to said predetermined radius.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The present invention is now to be explained more closely by means of different embodiments and with reference to the attached drawings.

(2) FIG. 1 shows a known combustor arrangement according to document EP 0 704 657 A2;

(3) FIG. 2 shows in a perspective view a burner, which can be advantageously used in a combustor arrangement according to the invention;

(4) FIG. 3 shows the burner of FIG. 2 equipped with a sliding joint in accordance with an embodiment of the invention; and

(5) FIG. 4 shows in a sectional view a combustor arrangement according to an embodiment of the invention with a sliding joint as shown in FIG. 3.

DETAILED DESCRIPTION

(6) As explained in the introductory part, the air leakage flow through the front panel sealing of existing EV and AEV burners bypasses the initial flame zone and is mixed later into the hot gas without premixing before with fuel. It is therefore detrimental for both NOx and CO production.

(7) By contrast, in the combustor arrangement according to the invention, an embodiment of which is shown in FIG. 4, the air leakages through the extractable burner parts and the sleeve are used on purpose, first to purge the gap between the sleeve and the burner ring and thus prevent flame stabilization at the burner ring's exit border. The air is then discharged into the mixing zone of the sleeve where it has sufficient time for premixing with the other fuel-air mixture before it reaches the flame zone stabilized at the diffuser type outlet of the burner sleeve.

(8) According to FIG. 4, a combustor arrangement 30 comprises a premix burner 21 extending along a central burner axis 34, and being equipped with a fuel lance 27 and a swirler configuration, which is shown in FIG. 2.

(9) The swirler configuration of FIG. 2 consists of burner shells 25, which are arranged around the central burner axis 34 and are parts of a virtual, axially extending common cone (not shown), which opens in a downstream direction, whereby said parts or shells 25 are displaced perpendicular to said burner axis 34 such that a tangential slot 36 is defined between each pair of adjacent shells 25.

(10) Each of the shells 25 is equipped with a premix gas channel 35 extending along an axially oriented edge of the respective shell such that a fuel gas can be injected from said premix gas channel 35 through gas injection holes (not shown) into a stream of air entering the interior of the arrangement of shells 25 through the adjacent slot 36.

(11) The downstream ends of the shells 25 and premix gas channels 35 are bordered by intersecting planes P1 and P2, respectively, which are defined by intersecting said shells 25 and premix gas channels 35 with a virtual coaxial cylinder of a predetermined radius.

(12) As shown in FIGS. 3 and 4, the swirler arrangement is surrounded by a cylindrical burner ring 26, which has an inner radius similar to said predetermined radius of said virtual cylinder. The burner ring 25 is fixed to the swirler arrangement and extends upstream of the downstream end of the burner 21 or swirler arrangement, respectively. in the centre of the swirler arrangement a fuel injector 28 is provided for injecting premix oil and/or pilot gas.

(13) The burner 21 with its burner ring 26 is slideably mounted in a coaxial burner sleeve 24. A seal 32 of the labyrinth type is positioned at the upstream end of the burner ring 26 between the burner ring 26 and the surrounding burner sleeve 24. The burner sleeve 24 has a conically widening burner outlet 29 at its downstream end and is fixed to a front panel 23 of the combustion chamber 22 (FIG. 4) with a circular flange 37. Further, the burner sleeve 24 has a bell-shaped air inlet 31 at its upstream end to guide combustion air into the swirler arrangement.

(14) Downstream of the seal 32 the burner sleeve 24 is equipped with an annular series of purge air holes 33, through which purge air can enter into an purge the gap between the burner ring 26 and the burner sleeve 24.

(15) The use of the burner sleeve 24 mounted on the front panel 23 of the combustion chamber 22 makes the axial position of the gas turbine burner 21 axially adjustable. It improves air velocity profiles along the burner slots 36 by directing with its air inlet 31 an air approach flow in axial direction and at the same time formes a mixing tube, where air leakages are mixed with fuel sufficiently far upstream in comparison to the flame. The burner sleeve 24 takes on the function of the burner mixing tube but is introduced as part of the front panel 23, avoiding the leakage problem mentioned above. Since the burner 21 is sliding inside the sleeve 24, there will be again a leakage, which, however is not harmful, as the leakage air is added upstream of the mixing tube and will take part in the mixing process upstream of the flame.

(16) Summarized, long cylindrical sleeves 24 shrouding the burners 21 are part of the combustor front panel 23. These sleeves 24 have a bell-shaped mouth or air inlet 31 to guide the air flow with a strong axial component to the burner slots 36. The sleeves 24 have radial air inlets or purge air holes 33 to purge the radial gap between the sleeves 24 and the burner rings 26 and to prevent flame stabilisation at the burner ring exit. Contrary to the existing AEV burner, the mixing zone is not part of the extractable burner 21 since the sleeves 24 themselves form the burner mixing zones before the outlet to the combustion chamber 22. At the outlet the sleeves have a diffuser shape (burner outlet 29) to better stabilize the flame.