CO-FIRING COMBUSTOR WITH GAS FUEL AND LIQUID AMMONIA

Abstract

Co-firing a combustor with gas fuel and ammonia using various approaches is disclosed. Each method fires a gas fuel in a primary combustion zone using a head end fuel nozzle, in a secondary combustion zone using a first axial fuel stage (AFS) injector set, and/or a tertiary combustion zone using a second AFS injector set over a particular combustor load range, and transitions to firing with ammonia using an ammonia atomizer. The methods may transition to ammonia combustion alone or ammonia with gas fuel combustion. The cross flow of the first AFS injector set stabilizes combustion of ammonia, and the second AFS injector set provides a quenching effect, each of which contributes to efficient ammonia combustion with or without gas fuel combustion.

Claims

1. A method, comprising: in a combustor including a head end (HE) fuel nozzle set aimed into a combustion liner to combust fuel in a primary combustion zone, a first axial fuel stage (AFS) injector set aimed into the combustion liner to combust fuel in a secondary combustion zone downstream of the primary combustion zone, and a second AFS injector set aimed into the combustion liner to combust fuel in a tertiary combustion zone downstream of the secondary combustion zone, and an ammonia atomizer aimed into the combustion liner to combust ammonia in at least the primary combustion zone, performing the following: for a first combustor load range from a 0% combustor load up to a 50% combustor load, fueling the HE fuel nozzle set to introduce and combust a gas fuel in the primary combustion zone; for a second combustor load range between a 10-20% combustor load range up to the 50% combustor load, additionally fueling the first AFS injector set to introduce and combust the gas fuel in the secondary combustion zone; for a third combustor load range between a 35% combustor load and the 50% combustor load, additionally fueling the second AFS injector set to introduce and combust the gas fuel in the tertiary combustion zone; at the 50% combustor load, transitioning to an ammonia fueling mode by stopping supply of the gas fuel to the HE fuel nozzle set, the first AFS injector set, and the second AFS injector set and starting combusting ammonia in at least the primary combustion zone using the ammonia atomizer; and for a fourth combustor load range between a greater than 50% combustor load and a 100% combustor load, fueling only the ammonia atomizer to introduce and combust ammonia in at least the primary combustion zone.

2. The method of claim 1, wherein, while gradually increasing a fuel mass flow rate (FMFR) of ammonia to the ammonia atomizer, the transitioning includes: gradually reducing the FMFR of the gas fuel to the HE fuel nozzle set to zero, then gradually reducing the FMFR of the gas fuel to the first AFS injector set to zero, and then gradually reducing the FMFR of the gas fuel to the second AFS injector set to zero.

3. The method of claim 2, wherein the transitioning further includes: temporarily maintaining the FMFR of ammonia to the ammonia atomizer at a first current level prior to starting the gradual reducing of the FMFR of the gas fuel to the first AFS injector set to zero and continuing the gradual increasing of the FMFR of ammonia to the ammonia atomizer after starting the gradual reducing of the FMFR of the gas fuel to the first AFS injector set to zero, and temporarily maintaining the FMFR of ammonia to the ammonia atomizer at a second current level prior to starting the gradual reducing of the FMFR of the gas fuel to the second AFS injector set to zero and continuing the gradual increasing of the FMFR of ammonia to the ammonia atomizer after starting the gradual reducing of the FMFR of the gas fuel to the second AFS injector set to zero.

4. The method of claim 3, wherein the transitioning further includes setting the FMFR of ammonia to the ammonia atomizer at a maximum desired level in response to the FMFR of the gas fuel to the second AFS injector reaching zero.

5. The method of claim 1, further comprising, for the fourth combustor load range between the greater than 50% combustor load and the 100% combustor load, injecting only air using the HE fuel nozzle set, the first AFS injector set, and the second AFS injector set.

6. A method, comprising: in a combustor including a head end (HE) fuel nozzle set aimed into a combustion liner to combust fuel in a primary combustion zone, a first axial fuel stage (AFS) injector set aimed into the combustion liner to combust fuel in a secondary combustion zone downstream of the primary combustion zone, and a second AFS injector set aimed into the combustion liner to combust fuel in a tertiary combustion zone downstream of the secondary combustion zone, and an ammonia atomizer aimed into the combustion liner to combust ammonia in at least the primary combustion zone, performing the following steps during a first co-fired mode: for a first combustor load range from a 0% combustor load up to a 50% combustor load, fueling the HE fuel nozzle set to introduce and combust a gas fuel in the primary combustion zone; for a second combustor load range between a 10-20% combustor load range up to the 50% combustor load, additionally fueling the first AFS injector set to introduce and combust the gas fuel in the secondary combustion zone; for a third combustor load range between a 35% combustor load and the 50% combustor load, additionally fueling the second AFS injector set to introduce and combust the gas fuel in the tertiary combustion zone; and for a fourth combustor load range between a 20% combustor load and a 100% combustor load, fueling the ammonia atomizer to introduce and combust ammonia in at least the primary combustion zone.

7. The method of claim 6, further comprising: at the 50% combustor load, transitioning to ammonia fuel operation by stopping the fueling of the HE fuel nozzle set, the first AFS injector set, and the second AFS injector set; and between the 50% combustor load and the 100% combustor load, injecting only air using the HE fuel nozzle set, the first AFS injector set, and the second AFS injector set.

8. The method of claim 6, wherein, during a second co-fired mode, the method comprises: fueling the second AFS injector set to introduce and combust the gas fuel in the tertiary combustion zone in a combustor load range between the 50% and combustor load and the 100% combustor load.

9. The method of claim 8, wherein between the 50% combustor load and the 100% combustor load, a gas fuel fraction of a total fuel amount is less than 20%.

10. The method of claim 8, further comprising, between the 50% combustor load and the 100% combustor load, injecting only air using the HE fuel nozzle set and the first AFS injector set.

11. The method of claim 6, wherein, during a third co-fired mode, the method comprises: fueling the HE fuel nozzle set to introduce and combust a gas fuel in the primary combustion zone in a combustor load range from the 50% combustor load up to the 100% combustor load; and fueling the second AFS injector set to introduce and combust the gas fuel in the tertiary combustion zone in a combustor load range between the 50% combustor load and the 100% combustor load.

12. The method of claim 11, wherein between the 50% combustor load and the 100% combustor load, a gas fuel fraction of a total fuel amount is between 20% and 50%.

13. The method of claim 11, further comprising, between the 50% combustor load and the 100% combustor load, injecting only air using the first AFS injector set.

14. The method of claim 6, wherein, during a fourth co-fired mode, the method comprises: fueling the HE fuel nozzle set to introduce and combust a gas fuel in the primary combustion zone between the 50% combustor load and the 100% combustor load; fueling the first AFS injector set to introduce and combust the gas fuel in the secondary combustion zone between the 50% combustor load and the 100% combustor load; and fueling the second AFS injector set to introduce and combust the gas fuel in the tertiary combustion zone between the 50% combustor load and the 100% combustor load.

15. The method of claim 14, wherein between the 50% combustor load and the 100% combustor load, a gas fuel fraction of a total fuel amount is greater than 50%.

16. A combustor for a turbomachine, the combustor comprising: a head end (HE) fuel nozzle set aimed into a combustion liner to combust fuel in a primary combustion zone; a first axial fuel stage (AFS) injector set aimed into the combustion liner to combust fuel in a secondary combustion zone downstream of the primary combustion zone; a second AFS injector set aimed into the combustion liner to combust fuel in a tertiary combustion zone downstream of the secondary combustion zone; an ammonia atomizer aimed into the combustion liner to combust ammonia in at least the primary combustion zone; and a controller configured to: sequentially supply a gas fuel to the HE fuel nozzle set, the first AFS injector set, and the second AFS injector set; and supply ammonia as an ammonia fuel to the ammonia atomizer from a 20% combustor load up to a 100% combustor load.

17. The combustor of claim 16, wherein the controller operates the combustor in a first co-fired mode of operation, which comprises the steps of: for a first combustor load range from a 0% combustor load up to a 50% combustor load, fueling the HE fuel nozzle set to introduce and combust the gas fuel in the primary combustion zone; for a second combustor load range between a 10-20% combustor load range up to the 50% combustor load, fueling the first AFS injector set to introduce and combust the gas fuel in the secondary combustion zone; for a third combustor load range between a 35% combustor load and the 50% combustor load, fueling the second AFS injector set to introduce and combust the gas fuel in the tertiary combustion zone; and between the 50% combustor load and the 100% combustor load, discontinuing the supply of gas fuel to the HE fuel nozzle set, the first AFS injector set, and the second AFS injector set.

18. The combustor of claim 16, wherein the controller operates the combustor in a second co-fired mode of operation, which comprises the steps of: for a first combustor load range from a 0% combustor load up to a 50% combustor load, fueling the HE fuel nozzle set to introduce and combust the gas fuel in the primary combustion zone; for a second combustor load range between a 10-20% combustor load range up to the 50% combustor load, fueling the first AFS injector set to introduce and combust the gas fuel in the secondary combustion zone; for a third combustor load range between a 35% combustor load and the 100% combustor load, fueling the second AFS injector set to introduce and combust the gas fuel in the tertiary combustion zone; and between the 50% combustor load and the 100% combustor load, discontinuing the supply of the gas fuel to the HE fuel nozzle set and the first AFS injector set.

19. The combustor of claim 16, wherein the controller operates the combustor in a third co-fired mode of operation, which comprises the steps of: for a first combustor load range from a 0% combustor load up to the 100% combustor load, fueling the HE fuel nozzle set to introduce and combust the gas fuel in the primary combustion zone; for a second combustor load range between a 10-20% combustor load range up to the 50% combustor load, fueling the first AFS injector set to introduce and combust the gas fuel in the secondary combustion zone; for a third combustor load range between a 35% combustor load and the 100% combustor load, fueling the second AFS injector set to introduce and combust the gas fuel in the tertiary combustion zone; and between the 50% combustor load and the 100% combustor load, discontinuing the supply of the gas fuel to the first AFS injector set.

20. The combustor of claim 16, wherein the controller operates the combustor in a fourth co-fired mode of operation, which comprises the steps of: for a first combustor load range from a 0% combustor load up to the 100% combustor load, fueling the HE fuel nozzle set to introduce and combust the gas fuel in the primary combustion zone; for a second combustor load range between a 10-20% combustor load range up to the 100% combustor load, fueling the first AFS injector set to introduce and combust the gas fuel in the secondary combustion zone; and for a third combustor load range between a 35% combustor load and the 100% combustor load, fueling the second AFS injector set to introduce and combust the gas fuel in the tertiary combustion zone.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0028] These and other features of this disclosure will be more readily understood from the following detailed description of the various aspects of the disclosure taken in conjunction with the accompanying drawings that depict various embodiments of the disclosure, in which:

[0029] FIG. 1 shows a functional block diagram of an illustrative gas turbine system that includes a combustor, according to embodiments of the disclosure;

[0030] FIG. 2 shows a simplified cross-sectional side view of an illustrative combustor, according to embodiments of the disclosure;

[0031] FIG. 3 shows an upstream view of a portion of the combustor shown in FIG. 2, according to embodiments of the disclosure;

[0032] FIG. 4 shows a bar graph representation of operation of various parts of a combustor based on combustor load percentage (%), according to embodiments of the disclosure; and

[0033] FIG. 5 shows a graphical representation of the transitioning that occurs at a 50% combustor load for the ammonia mode in FIG. 4, according to certain embodiments of the disclosure.

[0034] It is noted that the drawings of the disclosure are not necessarily to scale. The drawings are intended to depict only typical aspects of the disclosure and therefore should not be considered as limiting the scope of the disclosure. In the drawings, like numbering represents like elements between the drawings.

DETAILED DESCRIPTION

[0035] As an initial matter, in order to clearly describe the current disclosure, it will become necessary to select certain terminology when referring to and describing relevant machine components within the illustrative application of a turbomachine combustor. When doing this, if possible, common industry terminology will be used and employed in a manner consistent with its accepted meaning. Unless otherwise stated, such terminology should be given a broad interpretation consistent with the context of the present application and the scope of the appended claims. Those of ordinary skill in the art will appreciate that often a particular component may be referred to using several different or overlapping terms. What may be described herein as being a single part may include and be referenced in another context as consisting of multiple components. Alternatively, what may be described herein as including multiple components may be referred to elsewhere as a single part.

[0036] In addition, several descriptive terms may be used herein, and it should prove helpful to define these terms at the onset of this section. These terms and their definitions, unless stated otherwise, are as follows. As used herein, downstream and upstream are terms that indicate a direction relative to the flow of a fluid, such as the working fluid through a combustor of the turbomachine or, for example, the flow of air, gas fuel or ammonia through the combustor or nozzle, or coolant through one of the turbomachine's component systems. The term downstream corresponds to the direction of flow of the fluid, and the term upstream refers to the direction opposite to the flow. The terms forward and aft, without any further specificity, refer to directions, with forward referring to the front or compressor end of the turbomachine or combustor, and aft referring to the rearward or turbine end of the turbomachine or combustor.

[0037] The term axial refers to movement or position parallel to an axis, e.g., an axis of a combustor, a mixing chamber of the AFS injector, or turbomachine. The term radial refers to movement or position perpendicular to an axis, e.g., an axis of a combustor or a turbomachine. In cases such as this, if a first component resides closer to the axis than a second component, it will be stated herein that the first component is radially inward or inboard of the second component. If, on the other hand, the first component resides further from the axis than the second component, it may be stated herein that the first component is radially outward or outboard of the second component. Finally, the term circumferential refers to movement or position around an axis, e.g., a circumferential interior surface of a combustor body or a circumferential interior of casing extending about a combustor. As indicated above, and depending on context, it will be appreciated that such terms may be applied in relation to the axis of the combustor, nozzle or the turbine.

[0038] In addition, several descriptive terms may be used regularly herein, as described below. 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.

[0039] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. 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. Optional or optionally means that the subsequently described event may or may not occur or that the subsequently described feature may or may not be present and that the description includes instances where the event occurs, or the feature is present and instances where the event does not occur, or the feature is not present.

[0040] Where an element or layer is referred to as being on, engaged to, connected to, coupled to, or mounted to another element or layer, it may be directly on, engaged, connected, coupled, or mounted to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being directly on, directly engaged to, directly connected to, or directly coupled to another element or layer, there are no intervening elements or layers present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., between versus directly between, adjacent versus directly adjacent, etc.). As used herein, the term and/or includes any and all combinations of one or more of the associated listed items. The verb forms of couple and mount may be used interchangeably herein.

[0041] Embodiments of the disclosure provide methods of co-firing a combustor with gas fuel and liquid ammonia using various approaches. Each method fires a gas fuel in a primary combustion zone using a head end fuel nozzle set, in a secondary combustion zone using a first axial fuel stage (AFS) injector set and/or a tertiary combustion zone using a second AFS injector set, over one or more combustor load ranges. The methods transition to co-firing with ammonia using an ammonia atomizer. The methods may transition to ammonia combustion alone or ammonia with conventional gas fuel combustion. The cross flow of the first AFS injector set stabilizes combustion of ammonia, and the second AFS injector set provides a quenching effect. Each of these effects contributes to efficient ammonia combustion with or without conventional gas fuel combustion.

[0042] FIG. 1 shows a functional block diagram of an illustrative gas turbine (GT) system 90 that may incorporate various embodiments of a combustor 100 of the present disclosure. As shown, GT system 90 generally includes an inlet section 102 that may include a series of filters, cooling coils, moisture separators, and/or other devices to purify and otherwise condition air 106 entering GT system 90. Air 106 flows to a compressor 108 in a compressor section 110 that progressively imparts kinetic energy to air 106 to produce a compressed, high-pressure (HP) air 112 (hereafter air 112, HP air 112 or compressed air 112) at a highly energized state. HP air 112 is typically mixed with one or more fuels, e.g., fuels 114A and/or 114B, from a fuel source(s) 116 to form a combustible mixture within at least one combustor 100 in a combustion section 120 that is operatively coupled to compressor section 110. The combustible mixture is burned to produce combustion gases 122 having a high temperature and pressure. Combustion gases 122 flow through a turbine 128 (e.g., an expansion turbine) of a turbine section 130 operatively coupled to combustion section 120 to produce work. For example, turbine 128 may be connected to a shaft 132 so that rotation of turbine 128 drives compressor 108 to produce HP air 112. Alternatively, or in addition, shaft 132 may connect turbine 128 to another load, such as a generator 134 for producing electricity. Exhaust gases 136 from turbine 128 flow through an exhaust section 138 that connects turbine 128 to an exhaust stack 140 downstream from turbine 128. Exhaust section 138 may include, for example, a heat recovery steam generator (not shown) for cleaning and extracting additional heat from exhaust gases 136 prior to release to the environment. Where more than one combustor 100 is used (i.e., in a can-annular arrangement), they may be circumferentially spaced around a turbine inlet 142 of turbine 128.

[0043] In one embodiment, GT system 90 may be applicable in an engine model commercially available from GE Vernova of Cambridge, MA, and the present methods may be implemented in such engine models. The present disclosure is not limited to any one particular GT system and may be implemented in connection with other engines including, for example, any HA, F, B, LM, GT, TM and E-class engine models of GE Vernova, and engine models of other companies. Furthermore, the present disclosure is not limited to any particular turbomachine, and may be applicable to, for example, steam turbines, jet engines, compressors, turbofans, etc.

[0044] An illustrative combustor 100 usable within GT system 90 and its method of operation will now be described. FIG. 2 shows a cross-sectional side view of combustor 100 positioned within GT system 90. As shown in FIG. 2, combustor 100 is at least partially surrounded by an outer casing 150 such as a compressor discharge casing and/or a turbine casing. An interior plenum 152 of outer casing 150 is in fluid communication with a compressor discharge 109 of compressor 108 and creates an HP air source 154. That is, HP air source 154 includes HP air 112 from compressor discharge 109 of compressor 108. HP air source 154 is in direct fluid communication with compressor discharge 109 of GT system 90. However, HP air source 154 may be any supply of HP air 112 capable of flowing into any variety of opening or flow passage in combustor 100 to cool parts and/or for combustion, e.g., using, as will be described herein, head end (HE) fuel nozzle set 182 or axial fuel stage (AFS) injector sets 180, 200.

[0045] As shown in FIG. 2, combustor 100 for GT system 90 includes a combustor body 160. Combustor body 160 may be made using any now known or later developed techniques. For example, combustor body 160 may be additively manufactured and include a one-piece member 162 having a double-wall structure, as described below. Combustor body 160 may include a combustion liner 164, which may include, for example, a cylindrical portion 166 and a tapered transition portion 168. One or more liners or ducts form combustion liner 164 that may at least partially define a combustion reaction zone 186 (also referred to herein as combustion chamber 186) for combusting one or more fuel-air mixtures and that may at least partially define a hot gas path (HGP) through combustor 100 for directing combustion gases 122 towards turbine inlet 142 to turbine 128. Tapered transition portion 168 is at an aft end (right side as shown in FIG. 2) of cylindrical portion 166. As understood in the field, tapered transition portion 168 transitions the HGP from the circular cross-section of the liner's cylindrical portion 166 to a more arcuate cross-section for mating with turbine inlet 142 of turbine 128. Combustor 100 may also include an aft frame 167 at an aft end (right side in FIG. 2) of tapered transition portion 168.

[0046] Combustion liner 164 may have tapered transition portion 168 that is separate from cylindrical portion 166, as in many conventional combustion systems. Alternatively, as shown in FIG. 2, combustion liner 164 may have a unified body (or unibody) construction, in which cylindrical portion 166 and tapered transition portion 168 are integrated with one another, i.e., as part of additively manufactured one-piece member 162. Thus, any discussion of combustion liner 164 herein is intended to encompass both conventional combustion systems having a separate cylindrical and tapered transition portions and those combustion systems having a unibody liner. In any event, during operation, combustion liner 164 may contain and convey combustion gases 122 to turbine section 130 (FIG. 1). More particularly, combustion liner 164 defines a combustion chamber 186, i.e., in HGP, within which combustion occurs. Combustion gases 122 may include combusted gas fuel 114A and/or ammonia 114B as described herein.

[0047] Combustor body 160 also includes an air flow passage 170 defined at least partially by cylindrical portion 166 of combustion liner 164 (e.g., between inner and outer walls of the double-wall structure). As will be described herein, air flow passage 170 is configured to deliver HP air 112A from HP air source 154 to a head end assembly 172 of combustor 100 at a forward end (left end in FIG. 2) of combustion liner 164. That is, it is sized, shaped and/or arranged to deliver HP air 112A from HP air source 154 to head end assembly 172 of combustor 100, i.e., a high-pressure plenum 174 of head end assembly 172. Air flow passage 170 may be defined wholly within cylindrical portion 166, or air flow passage 170 may be provided between cylindrical portion 166 and a flow sleeve 176 spaced along at least a portion of an exterior surface of cylindrical portion 166. Air flow passage 170 has an open end 178 upstream (re. combustor 100) of, for example, a first axial fuel stage (AFS) injector set 180 through which HP air 112A from HP air source 154 enters.

[0048] Head end assembly 172 includes a head end (HE) fuel nozzle or burner set 182 (hereafter HE nozzle set 182) including a plurality of nozzles 184. Each nozzle 184 directs gas fuel 114A and air 112A into combustion reaction zone 186 of combustor 100. Each nozzle 184 may include any now known or later developed swozzle-based or micromixer-based nozzle. Combustion reaction zone 186 may include a primary combustion zone 188 in combustion liner 164. In certain embodiments, although not shown, axially extending HE fuel nozzle(s) 184 of head end assembly 172 may extend at least partially through a cap assembly 190 to provide a combustible mixture of gas fuel 114A and HP air 112A to primary combustion zone 188 of combustion reaction zone 186 in combustion liner 164. Gas fuel 114A may include natural gas or any other gas fuel, other than ammonia, typically employed in combustor 100. Gas fuel 114A may be delivered from fuel source 116 using any form of fuel line(s) 195.

[0049] Combustor 100 also includes a first axial fuel stage (AFS) injector set 180 directed into combustion liner 164 downstream of head end assembly 172. Each AFS injector 192 of set 180 receives air 112B from HP air source 154, among possibly other air flows, and gas fuel 114A from fuel source 116. Note, air 112A is directed into HP air plenum 174 in head end assembly 172, and air 112B is directed to AFS injector sets 180, 200. First AFS injector set 180 combusts gas fuel 114A and HP air 112B in a secondary combustion zone 194 of combustion reaction zone 186 in combustion liner 164. Gas fuel 114A may be delivered from fuel source 116 using any form of fuel line(s) 196. As illustrated, first AFS injector set 180 may include a plurality of circumferentially spaced AFS injectors 192. Any number of AFS injectors 192 can be used in first AFS injector set 180. For example, AFS injector set 180 may include a plurality of AFS injectors 192 circumferentially spaced around combustor body 160. Each AFS injector 192 extends radially through combustion liner 164 downstream from head end assembly 172, i.e., axially extending HE nozzle set 182.

[0050] Combustor 100 also includes a second axial fuel stage (AFS) injector set 200 directed into combustion liner 164 downstream of first AFS injector set 180. Each AFS injector 202 of set 200 receives HP air 112B from HP air source 154, among possibly other air flows, and gas fuel 114A from fuel source 116. Second AFS injector set 200 combusts gas fuel 114A and HP air 112B in a tertiary combustion zone 204 of combustion reaction zone 186 in combustion liner 164. Gas fuel 114A may be delivered from fuel source 116 using any form of fuel line(s) 206. As illustrated, second AFS injector set 200 may include a plurality of circumferentially spaced AFS injectors 202. Any number of AFS injectors 202 can be used in second AFS injector set 200. For example, AFS injector set 200 may include a plurality of AFS injectors 202 circumferentially spaced around combustor body 160. Each AFS injector 202 extends radially through combustion liner 164 downstream from first AFS injector set 180 and head end assembly 172, i.e., axially extending HE nozzle set 182.

[0051] Combustor 100 also includes an ammonia atomizer 210 (i.e., one or more atomizers 210) aimed into combustion liner 164 to combust liquid ammonia 114B in at least primary combustion zone 188. Ammonia atomizer(s) 210 may include any now known or later developed atomizer structure capable of creating a mist of liquid ammonia. Ammonia atomizer(s) 210 may include any number or form of nozzles to generate a desired ammonia mist. As illustrated, ammonia atomizer(s) 210 may be disposed centrally within head end plenum 174, such that atomized ammonia is distributed radially with a relatively even distribution into primary combustion zone 188.

[0052] FIG. 3 shows an upstream view of a portion of the combustor shown in FIG. 2, according to embodiments of the disclosure. In various embodiments, as shown in FIGS. 2 and 3 collectively, combustor 100 includes HE fuel nozzle set 182 including plurality of nozzles 184 whose upstream ends are coupled to an end cover 212 and which extend toward combustion reaction zone 186. The downstream ends of HE fuel nozzles 184 are aligned with respective openings (not separately labeled) in cap assembly 190, such that HE fuel nozzles 184 deliver a fuel/air mixture to combustion liner 164. Similarly, combustor 100 includes ammonia atomizer(s) 210 whose upstream ends are coupled to or extend through end cover 212 and which are aimed into combustion reaction zone 186. The downstream ends of ammonia atomizer(s) 210 are aligned with respective openings (not separately labeled) in cap assembly 190, such that ammonia atomizer(s) 210 deliver liquid ammonia in a spray or mist to combustion liner 164.

[0053] Various embodiments of combustor 100 may include different numbers and arrangements of HE fuel nozzles 184 and ammonia atomizer(s) 210, and the presently described embodiments are not limited to any particular number of nozzles or atomizers, unless otherwise specified in the claims. For example, in particular configurations, such as the configuration shown in FIG. 3, HE fuel nozzle set 182 includes annularly arranged HE fuel nozzles 184 with a center HE fuel nozzle 214. In other embodiments, HE fuel nozzles 184 may be annularly arranged about a centerline of end cover 212 without the use of center HE fuel nozzle 212. Center HE fuel nozzle 214 may also be a pre-mix, multiple-fuel (liquid fuel and gas fuel) type nozzle. Each HE fuel nozzle 184, 214 may be a swozzle-base nozzle or a micromixer based nozzle as those terms are understood in the field. In any event, each HE fuel nozzle 184, 214 may be used to mix gas fuel 114A, such as natural gas or other gas fuel, with air 112A, or simply pass 112A therethrough.

[0054] With regard to fuel delivery, a combustor controller 220 (FIG. 2) controls operation of various pumps and/or valves (not shown) to control delivery of gas fuel 114A with fuel lines 195, 196, 206 and/or ammonia 114B with fuel line(s) 216. As the operation of pumps and/or valves, among other gas fuel or liquid ammonia delivery structures, are known in the art, no further details are provided. A controller 220 is operationally coupled to any of the necessary pumps, valves, fuel lines and other fuel delivery structure to control operation thereof in accordance with embodiments of the disclosure. Controller 220 may include any hardware and/or software configured to control functioning of parts of combustor 100 described herein. Accordingly, where combustor 100 is indicated as conducting a particular function, controller 220 may be controlling the noted functions through control of any other structure or feedback sensors, such as but not limited to pumps, fans, valves, fuel lines, igniters, or fluid control vanes.

[0055] As shown in FIGS. 1-3, combustor 100 includes HE fuel nozzle set 182 aimed into combustion liner 164 to combust fuel in primary combustion zone 188, first AFS injector set 180 aimed into combustion liner 164 to combust fuel in secondary combustion zone 194 downstream of primary combustion zone 188, and second AFS injector set 200 aimed into combustion liner 164 to combust fuel in tertiary combustion zone 204 downstream of secondary combustion zone 194. Further, combustor 100 includes ammonia atomizer(s) 210 aimed into combustion liner 164 to combust ammonia 114B in at least primary combustion zone 188, and perhaps downstream combustion zones 194, 204 where complete ammonia combustion does not occur in primary combustion zone 188.

[0056] FIG. 4 shows a bar graph representation of operation of various parts of combustor 100 based on combustor load percentage (%). Notably, FIG. 4 shows operation of HE fuel nozzle set 182, first AFS injector set 180, second AFS injector set 200 and ammonia atomizer(s) 210. The legend in FIG. 4 shows cross-hatching indicators for each part of combustor 100 (FIG. 2). FIG. 4 will be used to described methods according to embodiments of the disclosure. As used herein, combustor load indicates a ratio of an amount of combustion gases being generated to a maximum amount of combustion gases combustor 100 is capable of generating, e.g., based on a draw of combustion gases 122 required to meet demand of turbine 128. Combustor load is represented as a percentage or percentage range. It will be recognized that operation of combustor 100 as described herein, i.e., according to the methods described herein, is controlled by controller 220 (FIG. 2).

[0057] An ammonia (NH.sub.3) mode is shown by the top set of bars in FIG. 4. With reference to FIGS. 2 and 4, during the ammonia mode, combustor 100, under control of controller 220, performs the following: for a first combustor load range from a 0% combustor load up to a 50% combustor load, combustor 100 combusts a gas fuel 114A in primary combustion zone 188 using HE fuel nozzle set 182. Here, gas fuel 114A is delivered to HE fuel nozzle set 182 and is mixed with air 112A and directed into and combusted in combustion liner 164, i.e., primary combustion zone 188 in combustion reaction zone 186. For a second combustor load range between a 10-20% combustor load range up to the 50% combustor load, combustor 100 additionally combusts gas fuel 114A in secondary combustion zone 194 using first AFS injector set 180. Here, gas fuel 114A is delivered to first AFS injector set 180 and is mixed with air 112B and directed into and combusted in combustion liner 164, i.e., secondary combustion zone 194 in combustion reaction zone 186. For a third combustor load range between a 35% combustor load and the 50% combustor load, combustor 100 additionally combusts gas fuel 114A in tertiary combustion zone 204 using second AFS injector set 200. Here, gas fuel 114A is delivered to second AFS injector set 200 and is mixed with air 112B and directed into combustion liner 164, i.e., tertiary combustion zone 204 in combustion reaction zone 186, and combusted.

[0058] A transition occurs to combustion with ammonia 114B at the 50% combustor load. More particularly, as shown in FIG. 4, at the 50% combustor load, transitioning occurs by stopping combusting gas fuel 114A using HE fuel nozzle set 182, first AFS injector set 180 and second AFS injector set 200 and starting combusting ammonia 114B in at least primary combustion zone 188 using ammonia atomizer(s) 210. At least in this setting indicates ammonia 114B may be combusted primarily in primary combustion zone 188, but some ammonia 114B may pass to and combust in secondary combustion zone 194 and/or tertiary combustion zone 204. For a fourth combustor load range between a greater than 50% combustor load and the 100% combustor load, combustor 100 combusts only ammonia 114B in at least primary combustion zone 188 using ammonia atomizer(s) 210. Here, gas fuel 114A flow to HE fuel nozzle set 182, first AFS injector set 180 and second AFS injector set 200 does not occur. Air 112A may continue to exit from HE fuel nozzle set 182, first AFS injector set 180 and/or second AFS injector set 200 to assist in the combustion.

[0059] FIG. 5 shows a graphical representation of the transitioning that occurs at the 50% combustor load for the ammonia mode in FIG. 4, according to certain embodiments of the disclosure. FIG. 5 shows a fuel mass flow rate (FMFR) to various parts of combustor 100 over time while at a 50% combustor load. With reference to FIGS. 2 and 5, the transition begins with the FMFR of ammonia 114B to ammonia atomizer(s) 210 being gradually increased, e.g., by controller 220 increasing ammonia flow to ammonia atomizer(s) 210. As used herein, gradually means the stated action occurs over a period of time and is not immediate or abrupt. While gradually increasing the FMFR of ammonia 114B to ammonia atomizer(s) 210, a number of FMFR reductions occur to other parts of combustor 100. More particularly, controller 220 gradually reduces the FMFR of gas fuel 114A to HE fuel nozzle set 182 to zero, e.g., starting at time T1 at extending to time T2. After gas fuel 114A to HE fuel nozzle set 180 is stopped (at time T2), controller 220 gradually reduces the FMFR of gas fuel 114A to first AFS injector set 180 to zero, e.g., from time T3 to time T4. This part of the transition may further include temporarily maintaining the FMFR of ammonia 114B to ammonia atomizer(s) 210 at a current level 300 (from time T2 to time T3) prior to starting the gradual reducing of the FMFR of gas fuel 114A to first AFS injector set 180 to zero (from time T3 to time T4) and continuing the gradual increasing of the FMFR of ammonia 114B to ammonia atomizer(s) 210 (from time T3 to time T4) after starting (and during) the gradual reducing of the FMFR of gas fuel 114A to first AFS injector set 180 to zero (from time T3 to time T4).

[0060] After gas fuel 114A to first AFS injector set 180 is stopped (at time T4), controller 220 gradually reduces the FMFR of gas fuel 114A to second AFS injector set 200 to zero (from time T5 to time T6). This part of the transition may further include temporarily maintaining the FMFR of ammonia 114B to ammonia atomizer(s) 210 at a current level 302 prior to starting the gradual reducing of the FMFR of gas fuel 114A to second AFS injector 200 set to zero (from time T5 to time T6) and continuing the gradual increasing of the FMFR of ammonia 114B to ammonia atomizer(s) 210 (from time T5 to time T6) after starting (and during) the gradual reducing of the FMFR of gas fuel 114A to second AFS injector set 200 to zero (from time T5 to time T6).

[0061] As ammonia 114B is injected by ammonia atomizer(s) 210, it vaporizes in combustion reaction zone 186, near first AFS injector set 180. At this stage, an ammonia-to-air ratio is very rich, e.g., between 1.1-1.5:1 ratio. A gas fuel-air mixture or air injected by first AFS injector set 180 assists in stabilizing the flame in primary combustion zone 188. Additionally, a gas fuel-air mixture or air from HE fuel nozzle set 182, e.g., a micromixer, also assists in atomizing ammonia 114B, to improve combustion in primary combustion zone 188. The transitioning further includes setting the FMFR of ammonia 114B to ammonia atomizer(s) 210 at a maximum desired level 304 in response to the FMFR of gas fuel 114A to second AFS injector set 200 reaching zero (at time T6). That is, controller 220 can force the two occurrences to be simultaneous or near simultaneous.

[0062] Returning to FIGS. 2 and 4, for the fourth combustor load range (of the ammonia mode) between the 50% combustor load and the 100% combustor load, gas fuel 114A flow to HE fuel nozzle set 182, first AFS injector set 180 or second AFS injector set 200 is stopped. Here, only ammonia 114B is being injected by ammonia atomizer(s) 210 and combusted in combustion reaction zone 186. However, air 112A continues to be injected into combustion liner 164 using HE fuel nozzle set 182, and air 112B continues to be injected into combustion liner 164 using first AFS injector set 180 and second AFS injector set 200. That is, once gas fuel 114A flow to HE fuel nozzle set 182, first AFS injector set 180 or second AFS injector set 200 is stopped, they inject air 112A, 112B only. The air injection further improves atomization of ammonia for improved combustion in any relevant combustion zone 188, 194, 204.

[0063] Continuing with FIGS. 2 and 4, a co-firing mode 1 is shown by the second from top set of bars in FIG. 4. During co-firing mode 1, combustor 100, under control of controller 220, performs the following: for a first combustor load range from a 0% combustor load up to a 50% combustor load, combustor 100 combusts a gas fuel 114A in primary combustion zone 188 using HE fuel nozzle set 182. Here, gas fuel 114A is delivered to HE fuel nozzle set 182 and is mixed with air 112A and directed into and combusted in combustion liner 164, i.e., primary combustion zone 188 in combustion reaction zone 186. For a second combustor load range between a 10-20% combustor load range up to the 50% combustor load, combustor 100 additionally combusts gas fuel 114A in secondary combustion zone 194 using first AFS injector set 180. Here, gas fuel 114A is delivered to first AFS injector set 180 and is mixed with air 112B and directed into and combusted in combustion liner 164, i.e., secondary combustion zone 194 in combustion reaction zone 186. For a third combustor load range between a 35% combustor load and the 50% combustor load, combustor 100 additionally combusts gas fuel 114A in tertiary combustion zone 204 using second AFS injector set 200. Here, gas fuel 114A is delivered to second AFS injector set 200 and is mixed with air 112B and directed into combustion liner 164, i.e., tertiary combustion zone 204 in combustion reaction zone 186, and combusted. For a fourth combustor load range between a 20% combustor load and the 100% combustor load, combustor 100 combusts ammonia 114B in at least primary combustion zone 188 using ammonia atomizer(s) 210. As noted, ammonia 114B may be combusted primarily in primary combustion zone 188, but some ammonia 114B may pass to and combust in secondary combustion zone 194 and/or tertiary combustion zone 204. As shown in FIG. 4, at the 50% combustor load, transitioning occurs by stopping combusting gas fuel 114A using HE fuel nozzle set 182, first AFS injector set 180, and second AFS injector set 200. Here, gas fuel 114A flow to HE fuel nozzle set 182, first AFS injector set 180, and second AFS injector set 200 does not occur. Air 112A may continue to exit from HE fuel nozzle set 182, first AFS injector set 180, and/or second AFS injector set 200 to assist in the combustion.

[0064] Continuing with FIGS. 2 and 4, a co-firing mode 2 is shown by the third from top set of bars in FIG. 4. During co-firing mode 2, combustor 100, under control of controller 220, performs the following: for a first combustor load range from 0% combustor load up to a 50% combustor load, combustor 100 combusts gas fuel 114A in primary combustion zone 188 using HE fuel nozzle set 182. Here, gas fuel 114A is delivered to HE fuel nozzle set 182 and is mixed with air 112A and directed into and combusted in combustion liner 164, i.e., primary combustion zone 188 in combustion reaction zone 186. For a second combustor load range between a 10-20% combustor load range up to the 50% combustor load, combustor 100 additionally combusts gas fuel 114A in secondary combustion zone 194 using first AFS injector set 180. Here, gas fuel 114A is delivered to first AFS injector set 180 and is mixed with air 112B and directed into and combusted in combustion liner 164, i.e., secondary combustion zone 194 in combustion reaction zone 186. For a third combustor load range between a 35% combustor load and a 100% combustor load, combustor 100 additionally combusts gas fuel 114A in tertiary combustion zone 204 using second AFS injector set 200. Here, gas fuel 114A is delivered to second AFS injector set 200 and is mixed with air 112B and directed into and combusted in combustion liner 164, i.e., tertiary combustion zone 204 in combustion reaction zone 186.

[0065] At the 50% combustor load, combustor 100, under control of controller 220, stops combusting gas fuel 114A using HE fuel nozzle set 182 and first AFS injector set 180. Here, gas fuel 114A is stopped to HE fuel nozzle set 182 and first AFS injector set 180, but continues flowing to second AFS injector set 200. For a fourth combustor load range between a 20% combustor load and the 100% combustor load, combustor 100 combusts ammonia 114B in at least primary combustion zone 188 using ammonia atomizer(s) 210 with the combusting of gas fuel 114A in tertiary combustion zone 204 using second AFS injector set 200. Hence, gas fuel 114A continues to be delivered to second AFS injector set 200 and is mixed with air 112B and directed into and combusted in combustion liner 164, i.e., tertiary combustion zone 204 in combustion reaction zone 186. However, between the 50% combustor load and the 100% combustor load, air 112A is injected using HE fuel nozzle set 182, and air 112B is injected by first AFS injector set 180. Due to HE fuel nozzle set 182 and first AFS injector set 180 not having gas fuel 114A delivered thereto between the 50% combustor load and the 100% combustor load, a gas fuel fraction of a total fuel amount is less than 20% during this part of co-firing mode 2.

[0066] Continuing with FIGS. 2 and 4, a co-firing mode 3 is shown by the fourth from top set of bars in FIG. 4. During co-firing mode 3, combustor 100, under control of controller 220, performs the following: for a first combustor load range from 0% combustor load up to a 100% combustor load, combustor 100 combusts gas fuel 114A in primary combustion zone 188 using HE fuel nozzle set 182. Here, gas fuel 114A is delivered to HE fuel nozzle set 182 and is mixed with air 112A and directed into and combusted in combustion liner 164, i.e., primary combustion zone 188 in combustion reaction zone 186. For a second combustor load range between a 10-20% combustor load range up to a 50% combustor load, combustor 100 additionally combusts gas fuel 114A in secondary combustion zone 194 using first AFS injector set 180. Here, gas fuel 114A is delivered to first AFS injector set 180 and is mixed with air 112B and directed into and combusted in combustion liner 164, i.e., secondary combustion zone 194 in combustion reaction zone 186. For a third combustor load range between a 35% combustor load and the 100% combustor load, combustor 100 additionally combusts gas fuel 114A in tertiary combustion zone 204 using second AFS injector set 200. Here, gas fuel 114A is delivered to second AFS injector set 200 and is mixed with air 112B and directed into and combusted in combustion liner 164, i.e., tertiary combustion zone 204 in combustion reaction zone 186.

[0067] At the 50% combustor load, combustor 100 stops combusting gas fuel 114A using first AFS injector set 180. Here, gas fuel 114A is stopped to first AFS injector set 180 but continues flowing to HE fuel nozzle set 182 and second AFS injector set 200. For a fourth combustor load range between a 20% combustor load and the 100% combustor load, combustor 100 combusts ammonia 114B in at least the primary combustion zone 188 using ammonia atomizer(s) 210 with combusting of gas fuel 114A in primary combustion zone 188 using HE fuel nozzle set 182 and tertiary combustion zone 204 using second AFS injector set 200. Hence, gas fuel 114A continues to be delivered to HE fuel nozzle set 182 and second AFS injector set 200 and is mixed with air 112A, 112B and directed into and combusted in combustion liner 164, i.e., primary combustion zone 188 and tertiary combustion zone 204 in combustion reaction zone 186. However, between the 50% combustor load and the 100% combustor load, only air 112B is injected using first AFS injector set 180. Due to first AFS injector set 180 not having gas fuel 114A delivered thereto between the 50% combustor load and the 100% combustor load, a gas fuel fraction of a total fuel amount is between 20% and 50% during this part of co-firing mode 3.

[0068] Continuing with FIGS. 2 and 4, a co-firing mode 4 is shown by the lowermost set of bars in FIG. 4. During co-firing mode 4, combustor 100, under control of controller 220, performs the following: for a first combustor load range from 0% combustor load and a 100% combustor load, combustor 100 combusts gas fuel 114A in primary combustion zone 188 using HE fuel nozzle set 182. Here, gas fuel 114A is delivered to HE fuel nozzle set 182 and is mixed with air 112A and directed into and combusted in combustion liner 164, i.e., primary combustion zone 188 in combustion reaction zone 186. For a second combustor load range between a 10-20% combustor load range and the 100% combustor load, combustor 100 additionally combusts gas fuel 114A in secondary combustion zone 194 using first AFS injector set 180. Here, gas fuel 114A is delivered to first AFS injector set 180 and is mixed with air 112B and directed into and combusted in combustion liner 164, i.e., secondary combustion zone 194 in combustion reaction zone 186. For a third combustor load range between a 35% combustor load and the 100% combustor load, combustor 100 additionally combusts gas fuel 114A in tertiary combustion zone 204 using second AFS injector set 200. Here, gas fuel 114A is delivered to second AFS injector set 200 and is mixed with air 112B and directed into and combusted in combustion liner 164, i.e., tertiary combustion zone 204 in combustion reaction zone 186.

[0069] For a fourth combustor load range between a 20% combustor load and the 100% combustor load, combustor 100 additionally combusts ammonia in at least primary combustion 188 zone using ammonia atomizer(s) 210 while also combusting gas fuel 114A in primary combustion zone 188 using HE fuel nozzle set 182, in secondary combustion zone 194 using first AFS injector set 180 and in tertiary combustion zone 204 using second AFS injector set 200. Hence, gas fuel 114A continues to be delivered to HE fuel nozzle set 182, first AFS injector set 180, and second AFS injector set 200 and is mixed with air 112A or 112B and directed into and combusted in combustion liner 164, i.e., primary combustion zone 188, secondary combustion zone 194, and tertiary combustion zone 204 in combustion reaction zone 186. Consequently, between the 50% combustor load and the 100% combustor load, a gas fuel fraction of a total fuel amount is greater than 50% during this part of co-firing mode 4.

[0070] In alternate modes of operations, ammonia atomizer(s) 210 can be used to inject diesel fuel or any other liquid fuel and combust with air either as a standalone fuel or with co-firing of natural gas.

[0071] The disclosure provides various technical and commercial advantages, examples of which are discussed herein. Embodiments of the methods provide efficient ammonia combustion with or without gas fuel combustion. As noted, the cross flow of the first AFS injector set stabilizes combustion of ammonia, and the second AFS injector set provides a quenching effect. Each of these effects contributes to efficient ammonia combustion with or without gas fuel combustion.

[0072] Approximating language, as used herein throughout the specification and claims, may be applied to modify any quantitative representation that could permissibly vary without resulting in a change in the basic function to which it is related. Accordingly, a value modified by a term or terms, such as about, approximately and substantially, are not to be limited to the precise value specified. In at least some instances, the approximating language may correspond to the precision of an instrument for measuring the value. Here and throughout the specification and claims, range limitations may be combined and/or interchanged; such ranges are identified and include all the sub-ranges contained therein unless context or language indicates otherwise. Approximately or about, as applied to a particular value of a range, applies to both end values and, unless otherwise dependent on the precision of the instrument measuring the value, may indicate +/10% of the stated value(s).

[0073] The corresponding structures, materials, acts, and equivalents of all means or step plus function elements in the claims below are intended to include any structure, material, or act for performing the function in combination with other claimed elements as specifically claimed. The description of the present disclosure has been presented for purposes of illustration and description but is not intended to be exhaustive or limited to the disclosure in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the disclosure. The embodiments were chosen and described in order to best explain the principles of the disclosure and the practical application of the technology and to enable others of ordinary skill in the art to understand the disclosure for contemplating various modifications to the present embodiments, which may be suited to the particular use contemplated.