Patent Application
20210301736
The present disclosure relates generally to a method of operating a fuel nozzle assembly within a combustor of a turbomachine.
Turbomachines are utilized in a variety of industries and applications for energy transfer purposes. For example, a gas turbine engine generally includes a compressor section, a combustion section, a turbine section, and an exhaust section. The compressor section progressively increases the pressure of a working fluid entering the gas turbine engine and supplies this compressed working fluid to the combustion section. The compressed working fluid and a fuel (e.g., natural gas) mix within the combustion section and burn in a combustion chamber to generate high pressure and high temperature combustion gases. The combustion gases flow from the combustion section into the turbine section where they expand to produce work. For example, expansion of the combustion gases in the turbine section may rotate a rotor shaft connected, e.g., to a generator to produce electricity. The combustion gases then exit the gas turbine via the exhaust section.
Particular combustion systems for gas turbine engines utilize combustors having multiple fuel nozzles for premixing a gaseous fuel with compressed air upstream from a combustion zone, as a means to keep nitrogen oxide (NOx) emissions low.
As renewable sources of power generation become increasingly popular and reliable, there is an increasing desire to have a greater gas turbine operational flexibility in order to integrate the gas turbine alongside a renewable system. One method for increasing the operational flexibility of a gas turbine is by sub-partitioning the fuel nozzles. However, issues exist with the current methods of operating fuel nozzles in this way. For example, many known fuel nozzles impart a swirl on the fuel/air mixture entering the combustion zone. The swirl of the fuel/air mixture in the combustion chamber leads to nozzle-to-nozzle interactions that negatively impact the NOx emissions. Additionally, known methods for sub-partitioning fuel nozzles do not meet emissions requirements while maintaining full operational flexibility.
Thus, an improved method for operating gas turbine fuel nozzles is desired in the art. In particular, methods that provide for full gas turbine operational flexibility while meeting emissions standards/requirements are desirable.
Aspects and advantages of the methods in accordance with the present disclosure will be set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the technology.
One embodiment of the present disclosure is a method for selectively operating a head end assembly of a combustor of a gas turbine. The head end assembly includes a plurality of bundled tube fuel nozzles. The method includes opening a first fuel circuit of a plurality of fuel circuits. The first fuel circuit of the plurality of fuel circuits is fluidly coupled to a first nozzle group of a plurality of nozzle groups, and the first nozzle group includes one bundled tube fuel nozzle of the plurality of bundled tube fuel nozzles. The method further includes adjusting an airflow received by the plurality of bundled tube fuel nozzles in response to opening the first fuel circuit of the plurality of fuel circuits. The airflow is adjusted based on an emissions output requirement corresponding with the first nozzle group. The method also includes firing the first nozzle group.
Another embodiment of the present disclosure is a method of selectively operating a head end assembly of a combustor of a gas turbine. The fuel nozzle assembly includes a plurality of bundled tube fuel nozzles. The method includes opening a first fuel circuit of a plurality of fuel circuits. The first fuel circuit of the plurality of fuel circuits is fluidly coupled to a first nozzle group of a plurality of nozzle groups. The first nozzle group includes one bundled tube fuel nozzle of the plurality of bundled tube fuel nozzles. The method further includes adjusting an airflow received by the plurality of bundled tube fuel nozzles from a compressor by adjusting the position of inlet guide vanes in response to opening the first fuel circuit of the plurality of fuel circuits. The airflow is adjusted based on an emissions output requirement corresponding with the first nozzle group. The method also includes firing the first nozzle group within the combustor.
These and other features, aspects and advantages of the present methods of operating a combustor having bundled tube fuel nozzles on different fuel circuits will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the technology and, together with the description, serve to explain the principles of the technology.
A full and enabling disclosure of the present methods, including the best mode of making and using the present systems and methods, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended figures.
Reference now will be made in detail to embodiments of the present methods of operating a combustor having bundled tube fuel nozzles on different fuel circuits, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation, rather than limitation of, the technology. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present technology without departing from the scope or spirit of the claimed technology. For instance, features illustrated or described as part of one embodiment can be used with another embodiment to yield a still further embodiment. Thus, it is intended that the present disclosure covers such modifications and variations as come within the scope of the appended claims and their equivalents.
The detailed description uses numerical and letter designations to refer to features in the drawings. Like or similar designations in the drawings and description have been used to refer to like or similar parts of the invention. As used herein, the terms “first”, “second”, and “third” may be used interchangeably to distinguish one component from another and are not intended to signify location or importance of the individual components.
As used herein, the terms “upstream” and “downstream” refer to the relative direction with respect to fluid flow in a fluid pathway. For example, “upstream” refers to the direction from which the fluid flows, and “downstream” refers to the direction to which the fluid flows.
It is sometimes necessary to describe parts that are disposed at different radial distances with respect to a center axis. The term “radially” refers to the relative direction that is substantially perpendicular to an axial centerline of a particular component; the term “axially” refers to the relative direction that is substantially parallel to, and/or coaxially aligned with, an axial centerline of a particular component; and the term “circumferentially” refers to the relative direction that extends around the axial centerline of a particular component.
As used herein, terms of approximation, such as “generally,” “about,” or “substantially” include values within ten percent greater or less than the stated value. When used in the context of an angle or direction, such terms include within ten degrees greater or less than the stated angle or direction. For example, “generally vertical” includes directions within ten degrees of vertical in any direction, e.g., clockwise or counter-clockwise.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
Although exemplary embodiments of the present disclosure will be described generally in the context of fuel nozzle assembly for a land-based power-generating gas turbine for purposes of illustration, one of ordinary skill in the art will readily appreciate that embodiments of the present disclosure may be applied to any style or type of fuel nozzle for a turbomachine and are not limited to combustors or combustion systems for land-based power-generating gas turbines unless specifically recited in the claims.
Referring now to the drawings,
During operation, air 24 flows through the inlet section 12 and into the compressor 14 where the air 24 is progressively compressed, thus providing compressed air 26 to the combustor 16. At least a portion of the compressed air 26 is mixed with a fuel 28 within the combustor 16 and burned to produce combustion gases 30. The combustion gases 30 flow from the combustor 16 into the turbine 18, wherein energy (kinetic and/or thermal) is transferred from the combustion gases 30 to rotor blades (not shown), thus causing the shaft 22 to rotate. The mechanical rotational energy may then be used for various purposes, such as to power the compressor 14 and/or to generate electricity. The combustion gases 30 exiting the turbine 18 may then be exhausted from the gas turbine 10 via the exhaust section 20.
The compressor 14 may include a plurality of circumferentially arranged cantilevered inlet guide vanes (“IGVs”) 21. The IGVs 21 are coupled to an actuator 23 and may be actuated by the controller 19 to regulate airflow flowing through the compressor 14. For example, during base-load-operation, the IGVs may be actuated to a fully open position, such as at an angle of approximately 90 degrees, to allow maximum airflow through the compressor 14. However, during part-load operation, the IGV angle may be set to a more closed position to reduce airflow through the compressor 14.
The gas turbine 10 may also include a plurality of fuel manifolds or circuits configured to deliver fuel to the various fuel nozzles within the combustor 16. For example, in one embodiment, a gas turbine 10 may include three fuel circuits (e.g., PM1, PM2 and PM3 fuel circuits, so named because the fuel supplied by the circuits is pre-mixed with air within the fuel nozzles before entering the combustion zone). It should be appreciated, however, that a gas turbine 10 may include any number and type of fuel circuits depending on the configuration of the gas turbine 10 and, thus, need not have the same number and type of fuel circuits described above. Additionally, depending on the particular mode at which a gas turbine 10 is operating, it should be appreciated that fuel may not be supplied through each of the fuel circuits. Further, each fuel circuit may be fluidly coupled to one or more valves 27. The one or more valves 27 may be configured to regulate the fuel flowing from each of the respective fuel circuits into the fuel nozzle assembly 100.
A fuel controller 29 may regulate the fuel 28 flowing from a fuel supply (48, shown in
As shown in
In particular embodiments, the head end portion 38 is in fluid communication with the high pressure plenum 34 and/or the compressor 14. One or more liners or ducts 40 may at least partially define a combustion chamber or zone 42 for combusting the fuel-air mixture and/or may at least partially define a hot gas path through the combustor (as indicated by an arrow) for directing the combustion gases 30 towards an inlet to the turbine 18.
In various embodiments, the combustor 16 includes a head end assembly 100. As shown in
In at least one embodiment, as shown in
As shown in
As shown in
As shown in
It should be noted that the specific size, spacing, and number of tubes 106 in the plurality of tubes 106 shown in the Figures is intended to be representative of the present bundled tube fuel nozzles 102, 104, 150 and should not be construed as limiting the present bundled tube fuel nozzles as having tubes of any particular size, spacing, or number. Moreover, it should be not construed as limiting the present bundled tube fuel nozzles as having tubes with a single tube diameter.
Utilizing any one of the bundled tube fuel nozzle assemblies 100 shown in
For example, the first nozzle group 300, which may include a center nozzle 102, may be operated in isolation at low gas turbine load requirements without the fuel/air exiting the center nozzle 102 being negatively impacted by air flowing through the adjacent/neighboring outer fuel nozzles 104, 152. Likewise, any nozzle group 300, 320, 340 may be operated in isolation or in any combination with another nozzle group 300, 320, 340 to meet a given gas turbine load requirement and corresponding emissions output requirement.
Each nozzle group 300, 320, 340 may be capable of firing entirely separately, all together, or in any combination within the combustor 16. For example, each fuel nozzle group 300, 320, 340 is fluidly coupled to one or more of the premix fuel manifolds or fuel circuits PM1, PM2, and PM3. In some embodiments, the first nozzle group 300 may fluidly coupled to the first premix manifold (“PM1”), the second nozzle group 320 may fluidly coupled to the second premix manifold (“PM2”), and the third nozzle group 340 may be fluidly coupled to the third premix manifold (“PM3”). As discussed above, the portion of fuel 28 flowing through the various fuel circuits (PM1, PM2, and PM3) and nozzle groups 300, 320, 340 is determined by the fuel controller 29 (
In order to maintain emission compliance at lower loads when operating the fuel nozzle groups 300, 320, and 340 separately, the amount of air and fuel supplied to the nozzles may be regulated. The air supplied to the fuel nozzle groups 300, 320 and 340 may be adjusted via the inlet guide vanes 21 at the inlet of the compressor 14 (as shown in
As discussed above, the portion of fuel 28 supplied to each nozzle group 300, 320, 340 is determined by the fuel controller 29 coupled to the various fuel circuits PM1, PM2, and PM3. The controller 19 and/or fuel controller 29 may maintain the proper fuel/air ratio exiting the nozzle groups 300, 320, 340 at any required load to advantageously allow for flexible operation of the gas turbine 10 while maintaining emissions requirements.
The fuel circuits PM1, PM2, PM3 and the inlet guide vanes 21 may together regulate the fuel/air ratio exiting the bundled tube fuel nozzle assembly 100 into the combustion zone 42 to maintain emissions compliance. Additionally, the fuel circuits PM1, PM2, PM3 and the inlet guide vanes 21 may be capable of regulating the fuel/air ratio exiting each of the fuel nozzle groups 300, 320, 340 to allow for segmented operation while maintaining emissions compliance. For example, fuel nozzle groups 300, 320, 340 may be operated in isolation, all together, or in any combination while maintaining emissions compliance.
In a ramp-up scenario, the first nozzle group 300 may be solely fired at the lower end of a load spectrum. As the gas turbine 10 load requirement increases, in many cases, the fuel and air supplied to the first nozzle group 300 may increase, and/or the second nozzle group 320 may begin to fire along with the first nozzle group 300 to meet the increased load. As the load requirement continues to increase up to full gas turbine load conditions, the fuel and air supplied to the first nozzle group 300 and second nozzle group 320 will continue to increase, and the third nozzle group 340 may begin to fire within the combustor 16 to meet the full load requirement.
Each nozzle group 300, 320, 340 may be selectively fired based on the required gas turbine required load, and, in some scenarios, different combinations of nozzle groups 300, 320, 340 may be utilized to meet the same load. For example, at a given gas turbine load requirement, the first nozzle group 300 may be fired along with the second nozzle group 320 to meet the gas turbine load while maintaining emissions requirements. Alternatively, at the same gas turbine load requirement, the third nozzle group 340 may be solely operated to meet the same gas turbine load while maintaining emissions requirements. In the embodiment shown in
In some embodiments, such as those shown in
Various embodiments of the head end assembly 100 may include any number of fuel nozzle groups/partitions and are not limited to any particular number of groups, unless otherwise specified in the claims. Similarly, each nozzle group may include any number of bundled tube fuel nozzles and is not limited to any particular number of bundled tube fuel nozzles, unless otherwise specified in the claims.
For example, in the embodiment shown in
The seven bundled tube fuel nozzles 102, 104, 150 may be partitioned into two fuel nozzle groups, e.g., a first nozzle group 350 and a second nozzle group 360. As shown, the first nozzle group 350 may include all of the outer fuel nozzles 104, 150, and the second nozzle group 360 may include only the center nozzle 102. Each of the fuel nozzle groups 350, 360 may be capable of isolated operation from the other nozzle group 350, 360. Each fuel nozzle group 350, 360 may be fluidly coupled to one or more premix manifolds or fuel circuits, e.g., the first nozzle group 350 may be fluidly coupled to a first fuel circuit PM1, and the second nozzle group 360 may be fluidly coupled to a second fuel circuit PM2.
Each fuel circuit PM1 and PM2 may be capable of regulating the fuel flow through the corresponding fuel nozzle groups 350, 360. Likewise, the air flow through each of the fuel nozzle groups 350, 360 may be regulated by the inlet guide vanes or IGVs 21 of the compressor 14. The fuel circuits PM1, PM2 and the inlet guide vanes 21 may together regulate the fuel/air ratio exiting the head end assembly 100 into the combustion zone 42 to maintain emissions compliance over various operating loads of the gas turbine 10. Additionally, the fuel circuits PM1, PM2 and the inlet guide vanes 21 may be capable of regulating the fuel/air ratio exiting each of the fuel nozzle groups 350, 360 to allow for segmented operation while maintaining emissions compliance.
In the embodiment shown in
Each of the fuel nozzle groups 400, 420, 440, 460 may be capable of isolated operation from the other nozzle groups 400, 420, 440, 460. Additionally, each fuel nozzle group 400, 420, 440, 460 may be operated in combination with another one or more nozzle groups 400, 420, 440, 460. Each fuel nozzle group 400, 420, 440, 460 may be fluidly coupled to one or more premix manifolds or fuel circuits, e.g., the first nozzle group 400 may be fluidly coupled to a first fuel circuit PM1, the second nozzle group 420 may be fluidly coupled to a second fuel circuit PM2, the third nozzle group 440 may be fluidly coupled to a third fuel circuit PM3, and the fourth nozzle group 460 may be fluidly coupled to a fourth fuel circuit PM4. Each fuel circuit PM1, PM2, PM3, PM4 may be capable of regulating the fuel flow through the corresponding fuel nozzle groups 400, 420, 440, 460.
Likewise, the air flow through each of the fuel nozzle groups 400, 420, 440, 460 may be regulated by the inlet guide vanes or IGVs 21 of the compressor 14. The fuel circuits PM1, PM2, PM3, PM4 and the inlet guide vanes 21 may together regulate the fuel/air ratio exiting the head end assembly 100 into the combustion zone 42 to maintain emissions compliance. Additionally, the fuel circuits PM1, PM2, PM3, PM4 and the inlet guide vanes 21 may be capable of regulating the fuel/air ratio exiting each of the fuel nozzle groups 400, 420, 440, 460 to allow for segmented operation while maintaining emissions compliance. For example, fuel nozzle groups 400, 420, 440, 460 may be operated in isolation, all together, or in any combination while maintaining emissions compliance.
In some embodiments, such as the ones shown in
In some embodiments (not shown), the method may further include opening a second fuel circuit PM1, PM2, PM3. The second fuel circuit may be fluidly coupled to a second group of fuel nozzles 300, 320, 340. The second group of fuel nozzles 300, 320, 340 may include one or more bundled tube fuel nozzles 200 that is not the same as the one bundled tube fuel nozzle 200 of the first nozzle group 300, 320, 340.
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 include 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.
