Abstract:
A combustion system uses a fuel nozzle with an inner wall having a fuel inlet in fluid communication with a fuel outlet in a fuel cartridge. The inner wall defines a mounting location for inserting the fuel cartridge. A pair of annular lip seals around the cartridge outer wall on both sides of the fuel outlet seals the fuel passage between the fuel inlet and the fuel outlet.

Description:
STATEMENT OF FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
       [0001]    This invention was made with Government support under Contract No. DE-FC26-05NT42643-DOE awarded by the Department of Energy. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    The subject matter disclosed herein relates to fuel delivery systems and more specifically, to fueling systems for gas turbine combustors. 
         [0003]    In general, gas turbines combust a mixture of compressed air and fuel within a combustor to produce hot combustion gases. The hot combustion gases rotate blades of the turbine to rotate a shaft that drives a load, such as an electrical generator. Mixing tubes within the combustor inject fuel and air into the combustor. In some designs, the mixing tubes pre-mix the fuel and air before the fuel and air enters the combustion zone. For example, the mixing tubes may be employed to mix a gaseous fuel with air. However, the fuel nozzles may not be designed to direct liquid fuel through the mixing tubes. A separate liquid fuel supply is permanently installed between the mixing tubes and sprays liquid fuel through a nozzle into the combustor, while another fuel passage feeds gaseous fuel into the mixing tubes. It is difficult to inspect internal components of the combustion system because they are typically enclosed in a sealed housing. 
         [0004]    The discussion above is merely provided for general background information and is not intended to be used as an aid in determining the scope of the claimed subject matter. 
       BRIEF DESCRIPTION OF THE INVENTION 
       [0005]    A combustion system uses a fuel nozzle with an inner wall having a fuel inlet in fluid communication with a fuel outlet in a fuel cartridge. The inner wall defines a mounting location for inserting the fuel cartridge. A pair of annular lip seals around the cartridge outer wall on both sides of the fuel outlet seals the fuel passage between the fuel inlet and the fuel outlet. Advantages that may be realized in the practice of some disclosed embodiments of the multi-fuel cartridge system include easier inspection and repair due to the removable cartridge, and less fuel tubes in the air feed plenum to reduce air flow disruptions. 
         [0006]    In one embodiment, a fuel nozzle assembly is disclosed which includes a fuel plenum, a fuel nozzle outer wall, and a fuel nozzle inner wall. The fuel nozzle inner wall defines a fuel cartridge location and a fuel plenum inlet which is in fluid communication with the fuel plenum. The fuel cartridge includes a fuel cartridge outer wall having a fuel cartridge outlet in fluid communication with the fuel plenum inlet when the cartridge is inserted into the cartridge location. Annular lip seals are disposed around the cartridge outer wall wherein a first one of the lip seals is on one side of the fuel cartridge outlet and a second one of the lip seals is on a second side of the fuel cartridge outlet. The lip seals seal the cartridge outer wall against the fuel nozzle inner wall in a substantially gas tight fashion. 
         [0007]    In another embodiment, a fueling system is disclosed which includes a fuel nozzle and a removable fuel cartridge. The fuel nozzle includes a fuel plenum, a plurality of parallel mixing tubes each for delivering an air/fuel mixture through an end of the mixing tube, and a fuel cartridge chamber for securing the fuel cartridge. Each of the mixing tubes have a proximal end for receiving air, a fuel aperture through a sidewall for receiving fuel, and a distal end for delivering the air/fuel mixture. The fuel cartridge chamber is disposed substantially in parallel with the mixing tubes and includes the removable fuel cartridge that contains the fuel. 
         [0008]    In another embodiment, a fuel nozzle system is disclosed that includes a fuel nozzle with an enclosed fuel plenum. Mixing tubes extend through the fuel nozzle, each including a first end in fluid communication with an air supply and a second end for delivering an air/fuel mixture. Apertures through the mixing tubes are in fluid communication with the fuel plenum. A mounting tube extends through the fuel nozzle for securing a removable fuel cartridge and is in fluid communication with the fuel plenum. 
         [0009]    This brief description of the invention is intended only to provide a brief overview of subject matter disclosed herein according to one or more illustrative embodiments, and does not serve as a guide to interpreting the claims or to define or limit the scope of the invention, which is defined only by the appended claims. This brief description is provided to introduce an illustrative selection of concepts in a simplified form that are further described below in the detailed description. This brief description is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. The claimed subject matter is not limited to implementations that solve any or all disadvantages noted in the background. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    So that the manner in which the features of the invention can be understood, a detailed description of the invention may be had by reference to certain embodiments, some of which are illustrated in the accompanying drawings. It is to be noted, however, that the drawings illustrate only certain embodiments of this invention and are therefore not to be considered limiting of its scope, for the scope of the invention encompasses other equally effective embodiments. The drawings are not necessarily to scale, emphasis generally being placed upon illustrating the features of certain embodiments of the invention. In the drawings, like numerals are used to indicate like parts throughout the various views. Thus, for further understanding of the invention, reference can be made to the following detailed description, read in connection with the drawings in which: 
           [0011]      FIG. 1  is a schematic flow diagram of an embodiment of a gas turbine system that may employ fuel nozzles with multi-fuel cartridges; 
           [0012]      FIG. 2  is a cross-sectional view of the combustor of  FIG. 1 ; 
           [0013]      FIG. 3  is a cross-sectional view of an embodiment of a fuel nozzle of the combustor of  FIG. 1 ; 
           [0014]      FIG. 4  is a cross section view of an embodiment of the fuel nozzle that includes a multi-fuel cartridge; and 
           [0015]      FIG. 5  is a cross section view of another embodiment of the fuel nozzle that includes a multi-fuel cartridge. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0016]    The present disclosure is directed to fuel nozzles that include multi-fuel cartridges. Each fuel nozzle may have a segmented shape, such as a wedge shaped cross section, that allows the fuel nozzle to fit together with adjacent fuel nozzles to form an annular ring of fuel nozzles within a combustor of a gas turbine. A series of mixing tubes are disposed within each fuel nozzle to produce a fuel-air mixture that is directed to the combustion zone. In particular, the mixing tubes direct air from an air plenum mixed with fuel from a fuel plenum through the mixing tubes to the nozzle face. The fuel plenum surrounds the mixing tubes and gaseous fuel from the fuel plenum is directed into the mixing tubes through apertures in the side of the tubes to produce the fuel-air mixture. The fuel nozzles also may include a multi-fuel cartridge that delivers the liquid fuel, such as fuel oil or other distillates, and the gaseous fuel, such as natural gas. Accordingly, the fuel nozzles described herein may provide the flexibility to operate on liquid fuel, gaseous fuel, or a combination thereof. The multi-fuel cartridge may be located within the fuel nozzle between the mixing tubes. Accordingly, the liquid fuel may be directed through the multi-fuel cartridge to the combustion zone without flowing through the mixing tubes, and the gaseous fuel may be directed through the mixing tubes to the combustion zone. 
         [0017]    The multi-fuel cartridge extends from the combustor front end cover through the fuel/air plenums to the nozzle face. The multi-fuel cartridge may be mounted within a cartridge holder tube that secures the multi-fuel cartridge between the mixing tubes. The multi-fuel cartridge includes an inner compartment, or passage, for storing liquid fuel and a cartridge nozzle connected to the inner compartment. The multi-fuel cartridge may also include one or more outer compartments, or passages, for storing and directing gaseous fuel to the mixing tubes. The multi-fuel cartridge may also include air and/or water passages to direct air, water, or a combination thereof, through the multi-fuel cartridge. The cartridge nozzle may be located at the end of the multi-fuel cartridge to expel, or spray, the liquid fuel into the combustion zone. According to certain embodiments, the cartridge nozzle expels, or sprays, the liquid fuel radially outward toward into the combustion zone. The mixing tubes may be disposed radially around the multi-fuel cartridge in a pattern designed to promote efficient mixing of the gaseous fuel and the liquid fuel. 
         [0018]      FIG. 1  is a block diagram of an embodiment of a gas turbine system  10  that employs sector fuel nozzles that include multi-fuel cartridges. The gas turbine system  10  may be part of a simple cycle system or a combined cycle system. The gas turbine system  10  includes a combustor  12  that combusts fuel  14  to drive the gas turbine system  10 . According to certain embodiments, the fuel  14  may be a liquid or gaseous fuel, or a combination thereof, such as natural gas, light or heavy distillate oil, naphtha, crude oil, residual oil, or syngas. 
         [0019]    Within the combustor  12 , the fuel  14  may mix with pressurized air  16 , shown by arrows, and ignition may occur, producing hot combustion gases  18  that power the gas turbine system  10 . As discussed further below with respect to  FIG. 2 , the combustor  12  includes sector fuel nozzles that pre-mix the gaseous fuel  14  and the pressurized air  16  and direct the fuel-air mixture into a combustion chamber in a suitable ratio for optimal combustion, emissions, fuel consumption, and power output. Further, the fuel nozzles also may include multi-fuel cartridges that direct liquid fuel into the combustion chamber. 
         [0020]    The pressurized air  16  includes intake air  20  that enters the gas turbine system  10  through an air intake section  22 . The intake air  20  is compressed by a compressor  24  to produce the pressurized air  16  that enters the combustor  12 . The sector fuel nozzles may direct the fuel  14  and the pressurized air  16  into the combustion zone of the combustor  12  together with the liquid fuel expelled from the multi-fuel cartridges. Within the combustion zone, the pressurized air  16  combusts with the liquid and gaseous fuel  14  to produce the hot combustion gases  18 . From the combustor  12 , the hot combustion gases  18  may flow through a turbine  26  that drives the compressor  24  via a shaft  28 . For example, the combustion gases  18  may apply motive forces to turbine rotor blades within the turbine  26  to rotate the shaft  28 . Shaft  28  also may be connected to a load  30 , such as a generator, a propeller, a transmission, or a drive system, among others. After flowing through the turbine  26 , the hot combustion gases  18  may exit the gas turbine system  10  through an exhaust section  32 . 
         [0021]      FIG. 2  is a cross-sectional view of an embodiment of the combustor  12 . The combustor  12  includes fuel nozzles  34  that inject the gaseous fuel-air mixture into a combustion chamber  36 . The combustion chamber  36  is generally defined by a casing  42 , and a liner  40 . 
         [0022]    The fuel nozzles  34  are arranged adjacent to one another to form a generally circular fuel nozzle assembly  44 . According to certain embodiments, each fuel nozzle  34  has a wedge-shaped cross section designed to abut a pair of adjacent fuel nozzles  34 . Further, in certain embodiments, each fuel nozzle  34  may be arranged around a central opening  46 . Each fuel nozzle  34  may extend outward from the central opening  46  in the radial direction  47 . Each fuel nozzle  34  includes mixing tubes  48  that mix the gaseous fuel  14  and air to form a fuel-air mixture that is injected into the combustion chamber  36 . One or more of the fuel nozzles  34  also may include a multi-fuel cartridge  50  that injects liquid fuel into the combustion chamber  36  and directs gaseous fuel to the mixing tubes  48 . These fuels may be contained under pressure within the multi-fuel cartridge  50 . As discussed further below with respect to  FIG. 3 , the mixing tubes  48  may be disposed around the multi-fuel cartridge  50 . 
         [0023]    The fuel nozzles  34  each include a base  52  that secures the fuel nozzle  34  of the combustor  12 . A shell  56  extends between the base  52  and mixing tube fuel/air plenums  58  in the axial direction  60 . The shell  56  generally encloses an air feed plenum  62  ( FIG. 3 ) that directs air from the compressor through the interior of the fuel nozzles  34  to the mixing tubes  48 , which extend through the mixing tube fuel/air plenums  58  to a face plate  66 . The shell  56  includes openings  64  that allow air flow  43  ( FIG. 4 ) from the compressor to enter the air feed plenum  62 . Within the mixing tube fuel/air plenums  58 , the gaseous fuel may enter the mixing tubes  48  through holes in the sides of the mixing tubes  48  to produce the fuel-air mixture that flows through the mixing tubes  48  to enter the combustion chamber  36 . The multi-fuel cartridge  50  extends through the base  52 , the air feed plenum  62 , and the mixing tube fuel/air plenums  58  to direct liquid fuel into the combustion chamber  36  and gaseous fuel into the mixing tubes  48 . Within the combustion chamber  36 , the gas and liquid fuel-air mixture is combusted to produce the hot combustion gases  18 . From the combustion chamber  36 , the hot combustion gases  18  flow to the turbine  26 . 
         [0024]      FIG. 3  depicts one of the fuel nozzles  34  sectioned to show the interior of the fuel nozzle  34 . The multi-fuel cartridge  50  extends through an aperture  72  in the base  52 , through the air feed plenum  62 , through the fuel plenum  132 , and through the air plenum  134  to the face plate  66 . The fuel plenum  132  is generally defined by a fuel plenum plate  74  and the interior plate  136 . The air plenum  134  is generally defined by the interior plate  136  and the face plate  66 . The interior plate  136  is disposed generally parallel to the fuel plenum plate  74  and the face plate  66  and divides the interior side of the outer housing, or outer wall,  130  into the fuel plenum  132  and the air plenum  134 . An alternative cooling plate  138  may be disposed adjacent the face plate  66  on its interior surface. The outer housing, or outer wall,  130  is coupled to the fuel plenum plate  74 , the interior plate  136 , and the cooling and face plates  138 ,  66 , respectively to enclose the fuel plenum  132  and the air plenum  134 . The outer housing  130  may include a series of air purge holes  140  that direct air into the air plenum  134 . The air from the air plenum  134  then flows through openings  141  in the cooling plate  138  to provide cooling to the face plate  66 . The air from the air plenum  134  may also flow out of the fuel nozzle  34  through openings  142  ( FIG. 4 ) between the mixing tubes and the face plate  66 , as shown by arrows  143  ( FIG. 4 ), thereby providing an aft face cooling air path by purging hot air and any fuel leaking into the air plenum  134 . 
         [0025]    The mixing tubes  48  extend through the fuel plenum  132  and the air plenum  134  and are mounted in apertures  78  in the fuel plenum plate  74 , apertures  79  in the inner plate  136 , and apertures  80  in the face plate  66 . The mixing tubes  48  include apertures  82  in the tube walls  84  that allow gaseous fuel from the fuel plenum  132  to enter the mixing tubes  48 . Air flow  43  enters the fuel nozzle  34  through openings  64  in the shell  56 , and then flows through the air feed plenum  62  to enter the ends of the mixing tubes  48  through the apertures  78  in the fuel plenum plate  74 . Within the mixing tubes  48 , the air mixes with fuel that enters the mixing tubes  48  through the apertures  82  to produce the fuel-air mixture that is directed into the combustion chamber  36 . In particular, the fuel-air mixture exits the mixing tubes  48  through the apertures  80  in the face plate  66 . In certain embodiments the air in air plenum  134  may be employed to cool the cooling plate  138 , and thereby the face plate  66  which is adjacent to the cooling plate  138 . 
         [0026]    The mixing tubes  48  are disposed radially around the multi-fuel cartridge  50 , which extends through an aperture  88  in the fuel plenum plate  74 , an aperture  89  in the inner plate  136 , and an aperture  90  in the face plate  66 . As shown in  FIG. 3 , the apertures  88 ,  89 , and  90  are centered within the fuel plenum plate  74 , the inner plate  136 , and the face plate  66 , respectively. Accordingly, the multi-fuel cartridge  50  extends axially through the approximate center of the fuel nozzle  34 . However, in other embodiments, the locations of the apertures  88 ,  89 , and  90  may vary to dispose the multi-fuel cartridge  50  in other positions within the fuel nozzle  34 . 
         [0027]    The multi-fuel cartridge  50  includes an inner tube  92  that defines an inner liquid fuel passage, or compartment,  94 , and an outer tube, or wall,  100  that defines a gaseous fuel passage, or compartment,  102 . According to certain embodiments, liquid fuel, water, and air, such as high-pressure atomizing air, may be supplied to the inner fuel compartment  94  of the multi-fuel cartridge  50  through inlets in the multi-fuel cartridge  50  that are external to the fuel nozzle  34 . The multi-fuel cartridge  50  also includes a nozzle portion  104  that expels, or sprays, the liquid fuel which may include water and/or air, from the inner passage  94  through the face plate  66  into the combustion chamber  36  ( FIG. 4 ). As shown, the multi-fuel cartridge  50  includes at least two concentric tubes, or interior walls,  92  and  100  that define two separate compartments  94  and  102 , respectively, whose contents may be pressurized. In other embodiments, any number of one or more tubes, or walls, may be included within the multi-fuel cartridge  50 . For example, in certain embodiments, the multi-fuel cartridge  50  may include an additional tube that defines a passage to separately supply water or air, or a combination thereof, to the combustion zone. 
         [0028]    The multi-fuel cartridge  50  is disposed within a mounting tube  106 , which also serves as the inner wall of the fuel nozzle  34 , that extends through the fuel plenum  132  and the air plenum  134  and is mounted within the aperture  88  in the fuel plenum plate  74 , aperture  89  in the inner plate  136 , and the aperture  90  in the face plate  66 . The mounting tube  106  may fit snugly within the apertures  88 ,  89 , and  90  to inhibit the escape of gaseous fuel through the apertures  88 ,  89 , and  90 . The mounting tube  106  may include a lip  110  designed to assist in the insertion of the multi-fuel cartridge into the mounting tube  106 . In some embodiments, the mounting tube  106  may fit snugly around the outer tube  100  of the multi-fuel cartridge  50 . In some embodiments, the inside diameter of the mounting tube  106  may be slightly greater than the outside diameter of the multi-fuel cartridge  50  to allow interoperation with lip seals mounted to the outer wall  100  of the multi-fuel cartridge  50 , as will now be described. 
         [0029]      FIG. 4  is a cross-sectional view of an embodiment of a fuel nozzle  34  containing a multi-fuel cartridge  50  fully inserted into the mounting tube  106 . The multi-fuel cartridge  50  comprises a pair of annular lip seals including a first lip seal  154  and a second lip seal  156 . The lips seals,  154 ,  156  are made from a thin sheet of metal, such as aluminum or an Inconel alloy, for example, curled into a substantially C-shaped cross-section and circumferentially attached to the outer wall  100  of the multi-fuel cartridge. The thin cross-section provides a flexible response from the lip seals  154 ,  156  against the inner wall of the mounting tube  106  when the multi-fuel cartridge  50  is inserted therein. The first lip seal  154  is seated against a first seal retention projection  158  which is formed on the inner wall of the mounting tube  106 . The second lip seal  156  is seated against a second seal retention projection  160  which is also formed on the inner wall of the mounting tube  106 . The seal retention projections  158 ,  160  include a curvature preferably contoured similar to the curvature of the corresponding lip seal  154 ,  156  to help provide a gas tight seal between the multi-fuel cartridge and the inner wall of the mounting tube  106  when the lip seals  154 ,  156  physically contact the seal retention projections  158 ,  160 . The first lip seal  154  may include a smaller diameter than second lip seal  156  to allow easier insertion of the multi-fuel cartridge  50  into the mounting tube  106 , in particular, to allow the first lip seal to more easily bypass the seal retention projection  160  without substantial interference therewith, thereby avoiding excessive wear that might otherwise result. The multi-fuel cartridge  50  may be inserted into mounting tub  106  via aperture  72  of the base  52 , then through the lip  110  of the mounting tube  106  until the cartridge nozzle  104  is seated in face plate  66  aperture  90 , and the first and second lip seals  154 ,  156  each abut their corresponding seal retention projections  158 ,  160 . The multi-fuel cartridge  50  may also be removed from the mounting tube  106  in a reverse fashion. This breach loading capability of the multi-fuel cartridge allows easy inspection of the interior of the fuel nozzle  34  using, for example, a boroscope inserted through aperture  72  of the base  52  when the multi-fuel cartridge  50  is removed. The outer wall  100  and the inner wall  92  of the multi-fuel cartridge  50 , and the mounting tube  106 , each comprise a substantially circular cross-section disposed substantially concentrically about multi-fuel cartridge axis  159 . 
         [0030]    The cartridge nozzle  104  is in fluid communication with the inner compartment  94  to expel liquid fuel from the inner compartment  94  into the combustion chamber  36 . As described above, the liquid fuel  14  may include light or heavy distillate oil, naphtha, crude oil, residual oil, or a combination thereof, and water and/or air. In one embodiment, the liquid fuel comprises an emulsion of fuel oil and water. When the multi-fuel cartridge  50  is fully inserted into the mounting tube  106 , the cartridge nozzle  104  is disposed in aperture  90  of the face plate  66 . The cartridge nozzle  104  may comprise an atomizing rotating air swirler  105 , with an annular ridge to assist insertion and fit of the cartridge nozzle  104  into the aperture  90 . 
         [0031]    The mounting tube  106  includes several openings forming fuel plenum inlets  150  between the interior of the mounting tube  106  and the fuel plenum  132 . The fuel plenum inlets are formed in the mounting tube between the fuel plenum plate  74  and the inner plate  136 . The multi-fuel cartridge  50  includes several openings through its outer wall  100  forming gaseous fuel outlets  152  corresponding to, and axially aligned with, the fuel plenum inlets  150 . Thus, gaseous fuel  14  in the outer passage  102  of multi-fuel cartridge  50  is in fluid communication with the fuel plenum  132  via the gaseous fuel outlets  152  and the fuel plenum inlets  150 , and may be delivered therethrough along a fuel flow path as indicated by arrows  153 . The gaseous fuel outlets  152  may be selectively sized to control a magnitude of gaseous fuel differential pressure across apertures  82  for controlling fuel injection therethrough to optimize fuel mixing in the mixing tubes  48 . The lips seals  154 ,  156  are disposed in a gas tight fashion on either side of the axially aligned fuel plenum inlets  150  and the gaseous fuel outlets  152  and between the outer wall of the multi-fuel cartridge  50  and the inner wall of the mounting tube  106  to secure passage of fuel into the gaseous fuel plenum  132  and to substantially prevent unnecessary dilution or leakage of the gaseous fuel. 
         [0032]      FIG. 5  is a cross-sectional view of an embodiment of the fuel nozzle  34  containing a multi-fuel cartridge  50  fully inserted into the mounting tube  106 . This embodiment is identical in all respects to the embodiment as shown in  FIG. 4  except that the second annular lip seal  156  now faces in an opposite direction and its corresponding retention projection  160  is positioned on the side of the second lip seal  156  away from gaseous fuel outlets  152 . The seal retention projection  160  includes a curvature preferably contoured similar to the curvature of the corresponding lip seal  156 , as before, to help provide a gas tight seal between the multi-fuel cartridge and the inner wall of the mounting tube  106 . This embodiment may be advantageous in applications wherein high gaseous fuel pressure is required because the higher fuel pressure expands the lip seals  154 ,  156  so that their outer surfaces press against the retention projections  158 ,  160  to form a gas tight seal, and so are better positioned to channel the fuel through the gaseous fuel outlets  152 . 
         [0033]    When fully assembled, the fueling system provided by the multi-fuel cartridge  50  delivers liquid and gaseous fuel  14  simultaneously to combustion chamber  36  using one cartridge in a simplified design. The air feed plenum  62  is kept uncluttered by other tubes typically required to provide fuel passages to the fuel plenum  132 , thereby avoiding wakes in the air flow and other air flow non-uniformities that might disrupt air delivery to the fuel nozzle  34 . The breach loading feature of the multi-fuel cartridge system further simplifies inspection by providing access to the interior of the fuel nozzle using visual inspection tools such as boroscopes. 
         [0034]    This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.