GB2123136A - A fuel burner and combustor assembly for a gas turbine engine - Google Patents

Abstract

A fuel burner and combustor assembly 12 for a gas turbine engine 10 has a housing 36 within the casing 20 of the gas turbine engine 10 which housing 36 defines a combustion chamber 50 and at least one fuel burner 35 secured to one end of the housing 36 and extending into the combustion chamber 50. The other end of the fuel burner 35 is arranged to slidably engage a fuel inlet connector 58 extending radially inwardly from the engine casing 20 so that fuel is supplied, from a source thereof, to the fuel burner 35. The fuel inlet connector 58 and fuel burner 35 coact to anchor the housing 36 against axial movement relative to the engine casing 20 while allowing relative radial movement between the engine casing 20 and the fuel burner 35 and, at the same time, providing fuel flow to the fuel burner 35. For dual fuel capability, a fuel injector 70 is provided in said fuel burner 35 with a flexible fuel supply pipe 72 so that the fuel injector70 and fuel burner 35 form a unitary structure which moves with the fuel burner 35. <IMAGE>

Description

SPECIFICATION Afuel burner and combustor assemblyfor a gas turbine engine The U.S. Government has rights to this invention pursuant to Contract No. EX76-C-01-2291 awarded by the U.S. Energy Research and DevelopmentAdministration (now the Department of Energy).

This invention relates to a fuel burner and combustor assembly for gas turbine engines and, more particularly, to a fuel burner and combustor assembly in which the fuel burnersupportsthecombustor housing or basket within the gas turbine engine.

The use of coal derived fuels, particularly in the United States because of its vast coal resources, has become increasingly important as an alternative energy source. Unfortunately, the energy content of gaseous fuel derived from coal is considerably lower than that of natural gas. Approximately, 150 BTU of heat is in a cubic foot of gaseous fuel derived from coal by the Lurgi process as compared to 900 BTU of heat in a cubicfoot of natural gas. In spite of the low energy contentofgaseousfuel derived from coal (hereinafter referred to as "LBG fuel"), it is desirableto provide a gas turbine engine capable of utilizing LBG fuel.

However, in a gas turbine electrical power generating system wherein the gas turbine engine is utilized to supply compressed airfor producing LBG fuel from coal bythe Lurgi process there is no LBGfuel available to be burned in the gas turbine engine until it is produced in the gasification process. This necessi tates that the gas turbine engine have the capability of burning, not only the LBG fuel, but anotherfuel, e.g.

natural gas, for start-up purposes and until the system produces LBG fuel.

Heretofore, as exemplified in the following patents, gas turbine engines have been designed to have dual fuel burning capabilities: U.S.PatentNo. 3,991,561 Leto November16, 1976 U.S. Patent No. 3,766,734 Jones October23,1973 U.S.PatentNo. 3,517,679 Williamson June30, 1970 U.S.PatentNo. 3,139,724 Nerad et al July7,1964 U.S. Patent No. 2,931,429 Brown April 5, 1960 U.S.PatentNo. 2,854,819 Walker October7,1958 U.S. Patent No. 2,771,741 Barnard 4th November 27,1955 British Patent No. 723,110 Morley February 2, 1955 However, in the heretofore known dual fuel burning gas turbine engines, the combustor and fuel nozzles or burners are independently supported so that problems of alignment and thermal differential expansion, between the combustor burner nozzles and the engine casing, exist.

According to the present invention there is provided a fuel burner and combustor assemblyfora gas turbine engine having a casing, an air compressor section disposed within said casing, a turbine section disposed within said casing in axial spaced relation to said aircompressorsection, and at least one fuel supply port means in the casing communicating with a source ofel and extending radially thereto, the fuel burner and combustor assembly comprising:: a) a housing disposed within the engine casing between the air compressor section and the turbine section and defining therein a combustion chamber; b) inlet port means in said housing communicating with the air compressor section and the combustion chamber to receive compressed airfrom said air compressor section and pass the same into the combustion chamber; c) said housing being closed at one end and open at the opposite end to pass gaseous products of combustiion from said combustion chamber into the turbine section to drive the latter;; d) atleastonefuel burnerattached atone end portion to said closed end of said housing and extending into the combustion chamberto pass fuel into the latter while the opposite end portion slidably engages said radially extending fuel supply port means for receiving fuel from the latter for passage through the fuel burner; and e) said fuel supply port means and fuel burner coactto anchor the housing against lateral movement and against movement in one axial direction relative to the casing so that thermal growth of the housing is effected in the opposite direction toward the turbine section and to allow relative movement between the combustor and casing in a radial direction while maintainingfuelflowthroughthefuel burner.The fuel supply port means and the fuel burnercoactto anchor the housing at one end against lateral movement and movement in an axial direction relative to the casing so thatthermal growth of the housing is effected in a direction toward the turbine section, and at the same time, to allow relative movement between the combustor and casing in a radial direction while maintain ingfuelflowthroughthefuel burner.

In a narrower aspect of the invention, the fuel burner includes a fuel injector disposed so asto emit a second fuel into the one end portion of the fuel burnerfor passagethrough the latter into the combustion chamber. Aflexiblefuel supply pipe is connected to the fuel injector and a source of a second fuel to provide forflow of the second fuel from the source thereoftothefuel injector.

The fuel burner and combustor assembly provides for fixing the housing ofthecombustoraxially, laterally and centrally within the gas turbine engine casing while, at the same time, providing the required allowanceforthe differential radial movement between the combustor housing and engine casing due to differential thermal expansion and contraction.

An embodiment ofthe invention will now be described, by way of an example, with reference to the accompanying drawings, in which Figure lisa side elevational view of a gas turbine engine provided with a fuel burnerand combustor assembly according to the present invention and which gas turbine engine may be employed to produce compressed air required in a process plant, as for examplethe Lurgi coal gasification process; Figure 2 is a fragmentary view in cross-section of the gasturbineengine shown in Figure 1; and Figure 3 is a view on an enlarged scale ofthefuel burner and combustor assembly shown in Figure 2.

Now, referring to the drawings and more particular lyto Figures 1 and 2, reference number 10 generally indicates a gas turbine engine having a fuel burner and combustorassembly 12 (see Figures 2 and 3) according to the present invention.

The gas turbine engine 10 is shown as being suitable for industrial use and the generation of compressed air, but the invention, while particularly suited to such gas turbine use, is not limited thereto.

Merely for purposes of illustrating the utility and the dual fuel capability ofthe present invention, the gas turbine engine 10 is shown as functioning to produce compressed airto be used in a process plant, as for example a Lurgi coal gasification plant (not shown).

Accordingly, gas turbine 10 is oftype which has an annular compressed air outlet manifold 14. The gas turbine engine 10, in addition to the outlet manifold 14, has a conventional aircompressorsub-assembly orsection 16 and turbine sub-assembly or section 18 axially spaced from each other in a casing 20. The rotors 22 of the air compressor section 16 and turbine section 18 are supported for rotation on a spool or shaft24which isjournaled in suitable bearing (not shown) supported bythe casing 20. Also, the gas turbine engine 10 has a fuel supply port means 26, which may, as shown, include an annularfuel inlet manifold 28 for LBG fuel.This fuel inlet manifold 28 is connected through a supply pipe 30 to a source (not shown) offuel, such a LBG fuel produced in a coal gasification process plant. Fuel inlet manifold 28 and compressed air outlet manifold 14 may be separate elements or may be constructed integrallywiththe casing 20 as is shown in Figures 2 and 3. The compressed air outlet manifold 14 is connected via a pipe 32 to a place of use such as the reactor (not shown) of a Lurgi coal gasification plant (not shown).

A crossovervalve means 31 is provided in the pipe 32 to control flow of compressed air into a by pass pipe 33 which communicates with pipe 30 so that some compressed air is bypassed to the inlet manifold 28 when liquid fuel isto be burned in the fuel burner and combustor assembly 12 and when LBG fuel is not yet availablefordeliverythrough the supply pipe 30. In the space between the air compressor section 16 and the turbine section 20, the casing 20 and conventional seals and baffling define therebetween a compressed air outlet plenum 34 within which is disposed the fuel burner and combustor assembly 12.

Thefuel burnerandcombustorassemblyl2com- prises a basket or housing 36 and a plurality of circumferentially spaced fuel burners 35 (only one of which is shown in the drawings) which are connected to and project into the housing 36.

The housing 36 comprises a conventional air cooled wall comprising a plurality of partially overlapping segmental plates 38 and spaced baffles 40. The baffles 40 define with the segmental plates 38 a passageway forcompressedair,which air maintains segmental plates 38 cool and enters the housing to support combustion therein. This type of combustor basket or housin is fully disclosed in the U.S.A. patent no.

3,267,676. As is conventional, the housing 36 is closed at one end by an annularwall 42 and open atthe opposite end 44, which end is supported, via a slipjoint connectiion 48, in the baffling defining compressed air plenum 34. The housing 36 defines therein an annular combustion chamber 50, which is in communication, through the open end portion 44, with the gas turbine section 18, to pass gaseous products of combustion from the combustion chamber 50 into the gas turbine section 18 to thereby drive the latter.

Thefuel burners 35 each comprise a hollow, tubular member 52 of L-shape and having a radially extending mounting flange 54 projecting from the axial or horizontal leg portion 52A. Each fuel burner 35 is disposed in an opening in the housing end wall 42 with the flange 54 in abutment againstthe end wall 42 and secured to the latter by bolts 56. The radial or vertical leg portion 52B of each fuel burner 35 is telescopically and slidably engaged with a threadless nipple 58 which forms part of the fuel supply port means 26.

Each nipple 58 is secured to the inner surface of the casing 20 in any suitable manner, as for example by bolts, not shown, so as to be in registerwith an outlet opening 60 and to project radially therefrom. As illustrated, the leg portion 52B has a diametral size so as to overlie and slidably engagethe outer surface of the associated nipple 58. The interstices between the leg portion 52B and an associated nipple 58 is sealed by seal means 62. Each of the seal means 62 may, as shown, comprisetwo spaced annular grooves in the outer surface of each nipple 58 in which are disposed O-Rings or other suitable seals, e.g. piston rings.The distal end of each fuel burner 35 in the combustion chamber 50 has an end cap member 64 which serves as a baffle for promoting vaporization ofthe liquid fuel impinging the inner surface ofthe cap member 64 before passing into the combustion chamber 50.

Associated with each fuel burner 35 is an igniter 66 which functions to ignite the fuel on start-up and before self-sustaining fuel combustion is reached in the combustion chamber 50. The fuel burners 35 function in cooperation with the nipples 58 to anchor the fuel burner and combustor assembly 12 in an axial direction and laterallywith respectto the casing 20 of the gas turbine engine 10. More specifically, this fixing of lateral and axial position is achieved by reason of leg portion 52B abutting nipples 58 fixed to the casing 20.This cooperative relationship offuel burners 35 and associated nipples 58 also provides for expansion and contraction of the housing 36 relative to the casing 20 in a direction towardstheturbine section 18 and slipjointconnection 48. Atthe same time, the fuel burner and combustor assembly 12 is permitted to move radially relativetothecasing 20 ofthe gas turbine engine 10. Furthermore, any potential minor assembly misalignments between the fuel burners 35 and their associated nipples 58 can be compensated for by suitable adjustments, as for example by adding or removing shims (not shown) between the mounting flanges 54 and the end wall 42. Since the burners 35 with respectto their associated nipples 58 are free-floating until bolted in place, no initial detrimental pre-stressing of fuel burners 35 can occur.

If, as previously stated, dual fuel capability is required because the application of gas turbine engine 10 is, as a generator of compressed air, for use in a reactor of a Lurgi coal gasification plant, each fuel burner 35 may include, as shown, a liquid fuel injector 70 which is supported in the tubular member 52 so as to extend coaxiallywithin the horizontal leg portion 52B. Each ofthefuel injectors 70 is connected to an external source of liquid fuel of high heat content by way of a flexible supply pipe 72 and connector 74 mounted on the casing 20.Since the injector70 is a partofthefuel burner and combustorassembly 12, it isfreeto movetogetherwith thetubular member52 by reason of the flexible connection with the casing 20 via the flexible pipe 72.

In operation ofthe gas turbine engine 10 as part of a Lurgi coal gasification plant, the gas turbine engine 10 is initially operated by burning in the combustion chamber 50, high energy liquid fuel flowing from the fuel inlet flexible supply pipes 72 through the injectors 70 and leg portion 52A of each fuel burner35. At the sametime,a portion ofthecompressed airflowing from compressed air plenum 34 into the pipe 32, via manifold 14, is bypassed, via the crossover valve means 31 and pipe 33 into the pipe 30 and manifold 28.

This bypassed compressed airflows,via outlet openings 60 and nipples 28, into the tubular members 52 for admixture with the liquid fuel emitted from the injectors 70 so as to promote the vaporization of the fuel. The combustion in the combustion chamber 50 is started bythe ingniter 66 and maintained by the ingniter66 until self-sustained combustion is attained.

With gas turbine engine 10 operating sufficently long enough to provide compressed air, via compressed air outlet manifold 14and outlet pipe 32forthe produc- tion of LBG fuel in the coal gasification plant (not shown), LBG fuel is then fed by means of suitable valving to the supply pipe 30 and fuel inlet manifold 28, thence into and through the tubular members 52 and into the combustion chamber 50. When LBG fuel is burned in the combustion chamber 50, liquid fuel flow is stopped and combustion is hereby maintained by burning the LBG fuel in the combustion chamber 50. This switch of fuels may be accomplished gradually by increasing LBG fuel flow while decreasing liquid fuel flow so that, during the transfer period, engine RPM can be maintained.

It is to be understood thatthe invention is not limited to fuel burner and combustor assemblies which comprise annular housings and a plurality ofcircum- ferentially spaced fuel burners as has been herein described in detail. It is within the scope and spirit of this inventionthatthefuel burner and combustor assembly may comprise a combustorhousing of the tank or can type having one or a plurality of spaced burners and wherein a plurality of such fuel burner and combustor assemblies are circumferentially arranged within the casing ofthe gas turbine engine.

Itisbelieved nowreadilyapparantthatthefuel burner and combustor assembly according to this invention provides the following: 1. low cost and maintenance and increased reliability by eliminating the need for the conventional combustorsupport pins; 2. no need forcomplex slipjoint connections between the fuel burners and combustorsince both are part of a unitary assembly; 3. eliminates heretofore known potential misalignment problems during gas turbine engine operation and the need for providing between conventional support pins and fuel burner nozzles compensating flexible connections; 4. fixes the combustor against axial and lateral movement relativeto the gasturbine engine casing while allowing radial movement relative to the casing;; 5. has liquid and gaseous fuel capability which is achievable from one to the other without disassembly or reassembly of the fuel system because both fuels are emitted from the same burner nozzle; 6. the switch from one fuel to the other can be achievedwithoutshutdown ofthegasturbineengine; and 7. a wide range of operating speeds is possible since operation is not dependent on the instantaneous availability of LBG fuel.

It is notthe intention hereofto restrict application of this invention by the figures and description thereof, but rather it should be understood thatthe present disclosure is to illustrate the concept and principle of the present invention and that changes or alterations thereto, obvious to one skilled in the art, would still come within the scope ofthis disclosure. Therefore, although but one preferred embodiment ofthe apparatus of this invention has been herein disclosed, it should be understood that the present invention is made byway of example only and that variations are possible without departing from the scope of the appended claims.

Claims (20)

1. Afuel burnerand combustorassemblyfora gas turbine engine having a casing, an air compressor section disposed within said casing, a turbine section disposed within said casing in axial spaced relation to said aircompressorsection, and at leastonefuel supply port means in the casing communicating with a source offuel and extending radially thereto, the fuel burner and combustor assembly comprising:: a) a housing disposed within the engine casing between the air compressor section and the turbine section and defining therein a combustion chamber; b) inlet port means in said housing communicating with the air compressor section and the combustion chamberto receive compressed airfrom said air compressor section and pass the same into the combustion chamber; c) said housing being closed at one end and open at the opposite end to pass gaseuos products of combustion from said combustion chamber into the turbine section to drive the latter;; d) atleastonefuel burnerattached atone end portion to said closed end of said housing and extending into the combustion chamberto pass fuel into the latterwhilethe opposite end portion slidably engages said radially extending fuel supply port meansfor receiving fuel from the latterfor passage through the fuel burner; and e) saidfuel supplyportmeansandfuel burner coactto anchorthe housing against lateral movement and against movement in one axial direction relative to the casing so that thermal growth of the housing is effected in the opposite direction toward theturbine section and to allow relative movement between the combustor and casing in a radial direction while maintainingfuelflowthroughthefuel burner.

2. Afuel burner and combustor assembly as claimed in claim 1, in which sealing means are provided between the fuel supply port means and the fuel burner.

3. Afuel burnerand combustor assembly as claimed in claim 1 or claim 2, in which said fuel burner is a hollowtubular member of generally L-shaped configuration.

4. Afuel burner and combustor assembly as claimed in any preceding claim, in which said fuel supply port means communicates with a manifold.

5. Afuel burner and combustor assembly as claimed in claim 4, in which said manifold is annular and surrounds the gas turbine.

6. Afuel burnerand combustor assembly as claimed in any preceding claim, in which said fuel supply port means comprises a nipple secured to the inner surface of the casing to project radially inwardly ofthe casing.

7. Afuel burnerand combustor assembly as claimed in claim 6, in which said fuel burnertelescopically engages said fuel supply port means.

8. Afuel burner and combustorassembly as claimed in claim 7, in which said nipple projects within thefuel burnerandwherein sealing means is disposed to seal the interstices between the nipple and fuel burner.

9. Afuel burnerandcombustorassemblyas claimed in any preceding claim, in which said fuel burner includes a fuel injector means and a flexible conduit connecting the fuel injector with a source of second fuel.

10. Afuel burner and combustorassemblyfora gas turbine engine having a casing, an air compressor section in said casing, a turbine section disposed within said casing in axial spaced relation to said air compressor section, and at least one fuel supply port means in the casing communicating with a source of fuel and extending radially thereto, the fuel burner and combustor assembly comprising:: a) a housing disposed within the engine casing in the space between the aircompressorand turbine sections and defining therein a combustion chamber; b) inlet port means in said housing communicating with the air compressor section to receive compressed air and to pass the same into the combustion chamber; c) said housing being closed at the end adjacent the air compressor section and open at the end adjacenttheturbine section to pass gaseous products of combustion into the turbine section to drive the latter;; d) at least one fuel burner of hollow tubular, L-shaped configuration having one leg portion thereof attached to and extending into the combustion chamberwhilethe other leg portion slidably engages said radially extending fuel supply port means so asto receive fuel from the latterfor passage th rough the fuel burner; and e) said fuel supply port means coacting with said fuel burnerto anchorthe combustor housing against lateral movement and movement in one axial direction relative to said casing so thatthermal growth of the combustor housing is effected in the opposite direction toward the turbine section and to simultaneously allow relative movement between the combustor and casing in a radial direction.

11. Afuel burner and combustor assembly as claimed in claim 10, in which said fuel supply port means includes a passageway in the casing and a nipple attached tothe casing in register with the passageway and projecting radially inwardly.

12. Afuel burner and combustor assembly as claimed in claim 11, in which said other leg portion of the fuel burnertelescopicallyslidablyengagessaid nipple so that relative radial movement with respect to the gas turbine engine can occur between the fuel burnerandcombustorassemblyand said engine casing.

13. Afuel burner and combustorassembly as claimed in claim 12, in which sealing means is provided between the other leg portion of the fuel burner and the nipple to prevent leakage of fuel through the interstices between the other leg portion and the nipple.

14. Afuel burner and combustor assembly as claimed in any one of claims lotto 13, in which said fuel burner has a fuel injector disposed to inject a secondfuel into said one leg portionforflow therethrough and into the combustion chamber.

15. Afuel burner and combustor assembly as claimed in claim 14, in which a flexible fuel supply pipe is connected at one end to said fuel injector and to a source of a second fuel.

16. Afuel burnerand combustorassemblyfora gasturbine engine having a casing, an air compressor section in said casing, aturbinesection disposed within said casing in axial spaced relation to said air compressor, and a plurality of circumferentially spaced fuel supply port connections extending radially and inwardlyfrom the casing and communicating with a source of fuel, the fuel burner and combustor assembly comprising:: a) an annular housing disposed within the engine casing in the space between the air compressor and turbine sections and defining therein an annular combustion chamber; b) inlet port means in the housing communicating with the compressed air section to receive compressed airfrom the latter and pass the same into the combustion chamber; c) said housing having ports communicating the aircompressorsection with the combustion chamber to supply airforsupporting combustion in the latter; d) said housing being closed atthe end adjacent the aircompressorsection and open at the end adjacent the turbine section to pass gaseous products of combustion into the turbine section to drive the latter; e) a fuel burnerfor each of said fuel supply port connectors; ; f) each of said fuel burners being attached at one end portion to said closed end of the housing and extending into the combustion chamberto pass fuel into the latterwhile the opposite end portiontelesco- pically engages its associated fuel supply port connec torfor receiving fuel from the latter; and g) each of said fuel burners and its associated fuel supply port connectorcoacting to anchor the combustor housing against movement in one axial direction relative to the casing sothatthermal growth of the combustor housing is allowed in direction toward the turbine section and to simultaneously allow relative movement between the combustor and casing in a radial direction while maintaining flow offuel through the fuel burner.

17. Afuel burner and combustor assembly as claimed in claim 16,inwhich each of said fuel burners is of hollow-tubular, L-shaped construction and wherein each of said fuel supply port connectors is a nipple secured to the inner surface ofthe casing so that it projects radially inwardly toward the longitudinal axis ofthe gas turbine engine.

18. Afuel burner and combustor assembly as claimed in claim 16 or claim 17, in which each of said fuel burners has a liquid fuel injector mounted thereon for discharge of fuel into fuel burners and wherein bypass means is provided for passing some ofthe compressed airfromthe aircompressorsection into each of said fuel burners to admix with the liquid fuel and promote vaporization ofthe liquid fuel.

19. Afuel burnerand combustorassemblyfora gas turbine engine, substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

20. Agasturbineengine provided with afuel burner and combustor assembly as claimed in any preceding claim.