Method of operating a gas turbine

Abstract

A method for operating a gas turbine according to one embodiment is a method for operating a gas turbine having a main nozzle and a pilot nozzle, and a combustor capable of using hydrogen and a fuel other than hydrogen as fuel. In the method for operating a gas turbine according to one embodiment, the ratio of the hydrogen mixing rate of the fuel injected from the pilot nozzle to the hydrogen mixing rate of the fuel injected from the main nozzle is such that, compared to a first ratio during low-hydrogen mixing rate operation, the second ratio during high-hydrogen mixing rate operation, where the hydrogen mixing rate is higher than during low-hydrogen mixing rate operation, is greater.

Description

Technology Field

[0001] The present disclosure relates to a method of operating a gas turbine.

[0002] The present application claims priority based on Japanese patent application No. 2022-192566 filed with the Japan Patent Office on December 1, 2022, and incorporates the contents thereof herein. Background Technology

[0003] For example, in thermal power plants, as a means to reduce the emission of carbon dioxide (CO2), which causes global warming, improvements in power generation efficiency or the active use of fuels other than fossil fuels, such as hydrogen, are being considered (see, for example, Patent Document 1). Prior art literature

[0004] Patent Document 1: Japanese Published Patent Application No. 2021-046949 The problem to be solved

[0005] To reduce carbon dioxide emissions, it is desirable to increase the hydrogen co-firing ratio. However, since hydrogen has low ignition energy and a fast combustion rate, increasing the hydrogen co-firing ratio increases the likelihood of flame backflow and other issues.

[0006] At least one embodiment of the present disclosure aims to increase the hydrogen mixing rate while suppressing flame backflow, etc., during the operation of a gas turbine, taking into account the circumstances described above. means of solving the problem

[0007] (1) A method of operating a gas turbine according to at least one embodiment of the present disclosure is,

[0008] A method of operating a gas turbine having a main nozzle and a pilot nozzle, and equipped with a combustor capable of using hydrogen and a fuel other than hydrogen as fuel, wherein

[0009] The ratio of the hydrogen co-firing ratio of the fuel injected from the pilot nozzle to the hydrogen co-firing ratio of the fuel injected from the main nozzle is such that, compared to the first ratio during low-hydrogen co-firing ratio operation, the second ratio during high-hydrogen co-firing ratio operation, where the hydrogen co-firing ratio is higher than during low-hydrogen co-firing ratio operation, is greater. Effects of the invention

[0010] According to at least one embodiment of the present disclosure, the hydrogen mixing rate can be increased while suppressing flame backflow, etc., during the operation of a gas turbine. Brief explanation of the drawing

[0011] FIG. 1 is a schematic diagram showing a gas turbine according to several embodiments. FIG. 2 is a cross-sectional view showing a combustion chamber according to several embodiments. FIG. 3 is a cross-sectional view showing the main parts of a combustion device according to several embodiments. FIG. 4 is a schematic diagram showing the arrangement of each fuel injector when viewed from the downstream side to the upstream side along the axial direction of the combustor according to several embodiments. FIG. 5 is a schematic diagram of a fuel supply system for a combustor according to several embodiments. Figure 6a is a graph showing an example of the relationship between the hydrogen mixing rate of each combustion burner and the hydrogen mixing rate of the entire combustion chamber during rated operation. Figure 6b is a graph showing an example of the relationship between the ratio of the hydrogen mixing rate in the pilot combustion burner to the hydrogen mixing rate in the main combustion burner and the hydrogen mixing rate in the entire combustion chamber, when the relationship between the hydrogen mixing rate of each combustion burner and the hydrogen mixing rate in the entire combustion chamber is as shown in Figure 6a. Figure 7a is a graph showing another example of the relationship between the hydrogen mixing rate of each combustion burner and the hydrogen mixing rate of the entire combustion chamber during rated operation. Figure 7b is a graph showing an example of the relationship between the ratio of the hydrogen mixing rate in the pilot combustion burner to the hydrogen mixing rate in the main combustion burner and the hydrogen mixing rate in the entire combustion chamber, when the relationship between the hydrogen mixing rate of each combustion burner and the hydrogen mixing rate in the entire combustion chamber is as shown in Figure 7a. Figure 8a is a graph showing another example of the relationship between the hydrogen mixing rate of each combustion burner and the hydrogen mixing rate of the entire combustion chamber during rated operation. Figure 8b is a graph showing an example of the relationship between the ratio of the hydrogen mixing rate in the pilot combustion burner to the hydrogen mixing rate in the main combustion burner and the hydrogen mixing rate in the entire combustion chamber, when the relationship between the hydrogen mixing rate of each combustion burner and the hydrogen mixing rate in the entire combustion chamber is as shown in Figure 8a. Figure 9a is a graph showing an example of the relationship between the hydrogen mixing rate of each combustion burner and the hydrogen mixing rate of the entire combustion chamber during partial load operation. Figure 9b is a graph showing an example of the relationship between the ratio of the hydrogen mixing rate in the pilot combustion burner to the hydrogen mixing rate in the main combustion burner and the hydrogen mixing rate in the entire combustion chamber, when the relationship between the hydrogen mixing rate of each combustion burner and the hydrogen mixing rate in the entire combustion chamber is as shown in Figure 9a. Specific details for implementing the invention

[0012] Hereinafter, several embodiments of the present disclosure will be described with reference to the attached drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of the components described as embodiments or shown in the drawings are not intended to limit the scope of the present disclosure and are merely illustrative examples.

[0013] For example, expressions indicating relative or absolute arrangements, such as "in a certain direction," "along a certain direction," "parallel," "orthogonal," "center," "concentric," or "coaxial," are meant to indicate not only strictly such arrangements but also a state of relative displacement by tolerances or angles or distances to the extent that the same function is obtained.

[0014] For example, expressions indicating that things are in an equivalent state, such as "identical," "equivalent," and "homogeneous," are meant to indicate not only a strictly equivalent state, but also a state in which tolerances or differences in the degree to which the same function is obtained exist.

[0015] For example, expressions representing shapes such as square or cylindrical shapes represent not only shapes such as square or cylindrical shapes in a geometrically strict sense, but also shapes including uneven surfaces or chamfers within the scope where the same effect is obtained.

[0016] Meanwhile, expressions such as "equip," "have," "provide," "include," or "have" a component are not exclusive expressions that exclude the existence of other components.

[0017] (Regarding the gas turbine (1))

[0018] FIG. 1 is a schematic diagram showing a gas turbine (1) according to several embodiments.

[0019] A gas turbine, which is an example of an application of the operating method of a gas turbine according to several embodiments, will be described with reference to FIG. 1.

[0020] As shown in FIG. 1, a gas turbine (1) operated by a method of operating a gas turbine according to several embodiments comprises a compressor (2) for generating compressed air as an oxidizer, a gas turbine combustor (4) for generating combustion gas using compressed air and fuel, and a turbine (6) configured to be driven by rotation by combustion gas. In the case of a gas turbine (1) for power generation, a generator not shown is connected to the turbine (6), and power generation is performed by the rotational energy of the turbine (6). In the following description, the gas turbine combustor (4) is also simply referred to as the combustor (4).

[0021] Specific configuration examples of each part in a gas turbine (1) regarding several embodiments will be described.

[0022] A compressor (2) according to several embodiments comprises a compressor chamber (10), an air intake port (12) provided on the inlet side of the compressor chamber (10) for inhaling air, a rotor (8) provided to penetrate both the compressor chamber (10) and the turbine chamber (22) described later, and various blades arranged within the compressor chamber (10). The various blades include an inlet guide blade (14) provided on the side of the air intake port (12), a plurality of static blades (16) fixed on the side of the compressor chamber (10), and a plurality of dynamic blades (18) installed on the rotor (8) to be arranged alternately with respect to the static blades (16). Additionally, the compressor (2) may be provided with other components such as an exhaust chamber not shown. In such a compressor (2), air drawn in from the air intake port (12) passes through a plurality of stationary vanes (16) and a plurality of moving vanes (18) and is compressed to become high-temperature, high-pressure compressed air. Then, the high-temperature, high-pressure compressed air is sent from the compressor (2) to a downstream combustor (4).

[0023] A combustor (4) according to several embodiments is disposed within a casing (20). As shown in FIG. 1, a plurality of combustors (4) may be arranged in an annular manner within the casing (20) with the rotor (8) at the center. Fuel and compressed air generated by the compressor (2) are supplied to the combustor (4), and combustion gas, which is the working fluid of the turbine (6), is generated by burning the fuel. Then, the combustion gas is transferred from the combustor (4) to the turbine (6) at the rear end. Furthermore, configuration examples of the combustor (4) according to several embodiments will be described later.

[0024] A turbine (6) according to several embodiments comprises a turbine chamber (22) and various blades arranged within the turbine chamber (22). The various blades include a plurality of static blades (24) fixed to the side of the turbine chamber (22) and a plurality of moving blades (26) installed on the rotor (8) so as to be arranged alternately with respect to the static blades (24). Additionally, the turbine (6) may be equipped with other components such as an outlet guide blade. In the turbine (6), the rotor (8) is driven to rotate as combustion gas passes through the plurality of static blades (24) and the plurality of moving blades (26). This causes a generator connected to the rotor (8) to be driven.

[0025] On the downstream side of the turbine chamber (22), the exhaust chamber (30) is connected through the exhaust chamber (28). The combustion gas after driving the turbine (6) is discharged to the outside through the exhaust chamber (28) and the exhaust chamber (30).

[0026] (Regarding the combustion device (4))

[0027] FIG. 2 is a cross-sectional view showing a combustor (4) according to several embodiments. FIG. 3 is a cross-sectional view showing a key part of a combustor (4) according to several embodiments. FIG. 4 is a schematic diagram showing the arrangement of each fuel injector when viewed from the downstream side to the upstream side along the axial direction of the combustor (4) according to several embodiments.

[0028] With reference to FIGS. 2, FIGS. 3 and FIGS. 4, the configuration of a combustion device (4) according to several embodiments will be described.

[0029] As shown in FIGS. 2 and 3, a combustor (4) according to several embodiments is arranged in a ring around a rotor (8) (see FIG. 1). Each combustor (4) includes a combustor liner (46) provided in a combustor compartment (40) defined by a casing (20), and a main combustion burner (60) and a pilot combustion burner (50), which are fuel injectors, respectively, arranged within the combustor liner (46).

[0030] The combustion device (4) further includes an outer tube (45) provided on the outer side of the inner tube (47) of the combustion device liner (46) inside the casing (20). An air passage (43) through which compressed air flows is formed on the outer side of the inner tube (47) and also on the inner side of the outer tube (45).

[0031] Additionally, the combustion device (4) may be equipped with other components, such as a bypass pipe (not shown) for bypassing combustion gas.

[0032] For example, the combustion liner (46) has an inner tube (47) positioned around a pilot combustion burner (50) and a plurality of main combustion burners (60), and a tail tube (48) connected to the tip of the inner tube (47). That is, the combustion liner (46) corresponds to a combustion section where fuel (F) injected from the main combustion burner (60) and the pilot combustion burner (50) is burned.

[0033] As shown in FIGS. 3 and 4, the pilot combustion burner (50) is arranged along the central axis of the combustion liner (46). Then, a plurality of main combustion burners (60) are spaced apart from each other and arranged in a circumferential direction to surround the outer side of the pilot combustion burner (50).

[0034] As shown in FIG. 3, the pilot combustion burner (50) has a pilot nozzle (54) connected to a fuel port (52), a pilot burner container (56) arranged to surround the pilot nozzle (54), and a plurality of swirlers (swivel plates) (58) provided on the outer circumference of the pilot nozzle (54).

[0035] The pilot nozzle (54) extends in the axial direction (Da) centered on the combustion axis (Ac).

[0036] Here, one side of the axis direction (Da), which is the extension direction of the combustion axis (Ac), and the upstream side following the flow of combustion gas is designated as the upstream side, and the other side and the downstream side following the flow of combustion gas is designated as the downstream side. Also, the combustion axis (Ac) is also the burner axis of this pilot combustion burner (50).

[0037] At the downstream end of the pilot nozzle (54), an injection hole (not shown) for injecting fuel (F) is formed. Upstream of the location where the injection hole is formed in the pilot nozzle (54), a plurality of pivot plates (58) are provided. Each pivot plate (58) is intended to pivot compressed air around the combustion axis (Ac). Each pivot plate (58) extends from the outer circumference of the pilot nozzle (54) in a direction containing a radial component and is close to the inner circumference of the pilot burner container (56). The pilot burner container (56) has a main body part (56a) located on the outer circumference of the pilot nozzle (54) and a cone part (56b) connected to the downstream side of the main body part (56a) and gradually widening toward the downstream side. The plurality of pivot plates (58) are close to the inner circumference of the main body part (56a) in the pilot burner container (56).

[0038] The pilot nozzle (54) suppresses the flame temperature and NO x It is configured to have an unillustrated water flow path to suppress the metal temperature of the cone (56b) and to allow water to be sprayed.

[0039] The main combustion burner (60) has a main nozzle (64) connected to a fuel port (62), a main burner tube (66) arranged to surround the main nozzle (64), an extension tube (65) connecting the main burner tube (66) and a combustion liner (46) (e.g., an inner tube (47)), and a swirler (swivel plate) (70) provided on the outer circumference of the main nozzle (64).

[0040] The main nozzle (64) is a rod-shaped nozzle extending in an axial direction (Da) centered on a burner axis (Ab) parallel to the combustion axis (Ac). Also, since the burner axis (Ab) of the main combustion burner (60) is parallel to the combustion axis (Ac), the axial direction (Da) with respect to the combustion axis (Ac) and the axial direction (Da) with respect to the burner axis (Ab) are the same direction. Furthermore, the upstream side of the axial direction (Da) with respect to the combustion axis (Ac) is the upstream side of the axial direction (Da) with respect to the burner axis (Ab), and the downstream side of the axial direction (Da) with respect to the combustion axis (Ac) is the downstream side of the axial direction (Da) with respect to the burner axis (Ab).

[0041] In the middle portion along the axial direction (Da) of the main nozzle (64), an injection hole for injecting fuel (F) is formed. Near the location where the injection hole is formed in the main nozzle (64), a plurality of pivot plates (70) are provided. Each pivot plate (70) is intended to pivot compressed air around the burner axis (Ab). Each pivot plate (70) extends from the outer circumference of the main nozzle (64) in a direction including a radial component and is close to the inner circumference of the main burner container (66). The main burner container (66) is located on the outer circumference of the main nozzle (64).

[0042] In the combustion device (4) having the above configuration, compressed air generated by the compressor (2) is supplied into the combustion device chamber (40) from the chamber inlet (40a), and also flows from the combustion device chamber (40) into the pilot burner chamber (56) and a plurality of main burner chambers (66) via the air passage (43).

[0043] In the pilot combustion burner (50), fuel (F) injected from the pilot nozzle (54) along with compressed air is ejected from the downstream end of the pilot burner container (56). This fuel (F) undergoes diffusion combustion or premixed combustion within the combustion liner (46).

[0044] That is, the pilot combustion burner (50) shown in FIGS. 2, FIGS. 3 and FIGS. 4 is a fuel injector of the diffusion combustion type or premixed combustion type.

[0045] In the main combustion burner (60), compressed air and fuel (F) injected from the main nozzle (64) are mixed within the main burner container (66) to form a premixed gas (PM). In the main combustion burner (60), the premixed gas (PM) is ejected from the downstream end of the extension pipe (65). The fuel (F) in this premixed gas (PM) undergoes premixed combustion within the combustion liner (46).

[0046] That is, the main combustion burner (60) shown in FIGS. 2, FIGS. 3 and FIGS. 4 is a premixed combustion type fuel injector.

[0047] Additionally, a spray hole for spraying fuel (F) may be formed in the swivel plate (70), and fuel (F) may be sprayed into the main burner container (66) from there. In this case, the part corresponding to the rod-shaped main nozzle (64) described above forms a hub rod, and the main nozzle is formed by having this hub rod and a plurality of swivel plates (70). Fuel (F) from the outside is supplied into the hub rod, and fuel (F) is supplied from this hub rod to the swivel plate (70).

[0048] (Regarding fuel (F))

[0049] In some embodiments of the combustor (4), natural gas is used as fuel (F), for example, in the same way as in conventional combustors, and hydrogen is also used. In addition, in the following description, natural gas as fuel (F) is referred to as natural gas fuel (FN) or simply natural gas. Likewise, in the following description, hydrogen as fuel (F) is referred to as hydrogen fuel (FH) or simply hydrogen.

[0050] Also, in the following description, where there is no need to specifically distinguish between natural gas fuel (FN), hydrogen fuel (FH), and a mixture of natural gas fuel (FN) and hydrogen fuel (FH) (FM), or where these fuels are collectively referred to as fuel (F).

[0051] (Regarding the fuel (F) supply system)

[0052] FIG. 5 is a schematic diagram of a fuel (F) supply system (200) for a combustor (4) according to several embodiments. A gas turbine (1) according to several embodiments includes a fuel (F) supply system (200) as shown in FIG. 5. The fuel (F) supply system (200) as shown in FIG. 5 includes a first supply line (211) for supplying natural gas fuel (FN) to a main combustion burner (60), a second supply line (212) for supplying natural gas fuel (FN) to a pilot combustion burner (50), a third supply line (221) for supplying hydrogen fuel (FH) to the main combustion burner (60) and the pilot combustion burner (50), and a fourth supply line (222) for supplying hydrogen fuel (FH) to the pilot combustion burner (50).

[0053] Natural gas fuel (FN) is supplied from a source of natural gas fuel (FN) (201) through a natural gas supply line (210). The first supply line (211) and the second supply line (212) are branched at a branching section (231).

[0054] The first supply line (211) is provided with a first control valve (241) for adjusting the amount of fuel (F) supplied to the main combustion burner (60). The downstream end of the first supply line (211) is connected to a fuel port (62) to which the main nozzle (64) of the main combustion burner (60) is connected.

[0055] The second supply line (212) is provided with a second control valve (242) for adjusting the amount of fuel (F) supplied to the pilot combustion burner (50). The downstream end of the second supply line (212) is connected to a fuel port (52) to which the pilot nozzle (54) of the pilot combustion burner (50) is connected.

[0056] Hydrogen fuel (FH) is supplied from a hydrogen fuel (FH) source (202) through a hydrogen supply line (220). A third supply line (221) and a fourth supply line (222) are branched at a branching section (232).

[0057] The third supply line (221) is provided with a third control valve (243) for adjusting the supply amount of hydrogen fuel (FH) to the main combustion burner (60) and the pilot combustion burner (50). The downstream end of the third supply line (221) is connected to the natural gas supply line (210) at a junction (233) upstream of the branch section (231) in the natural gas supply line (210).

[0058] That is, the third control valve (243) is a control valve for controlling the amount of hydrogen fuel (FH) added to the natural gas fuel (FN) flowing through the natural gas supply line (210).

[0059] The fourth supply line (222) is provided with a fourth control valve (244) for adjusting the amount of hydrogen fuel (FH) supplied to the pilot combustion burner (50). The downstream end of the fourth supply line (222) is connected to the second supply line (212) at a junction (234) downstream from the second control valve (242) in the second supply line (212).

[0060] That is, the fourth control valve (244) is a control valve capable of controlling the amount of hydrogen fuel (FH) added to the natural gas fuel (FN) flowing through the second supply line (212), or to the mixed fuel (FM) of natural gas fuel (FN) and hydrogen fuel (FH). Additionally, as described below, by closing the second control valve (242) and opening the fourth control valve (244), only hydrogen fuel (FH) can be supplied to the pilot combustion burner (50).

[0061] In the fuel (F) supply system (200) configured in this way, by adjusting the opening of the first control valve (241), the second control valve (242), the third control valve (243), and the fourth control valve (244), the hydrogen mixing ratio (calorie ratio), which is the ratio of hydrogen fuel (FH) to the fuel (F) injected in the main combustion burner (60) and the pilot combustion burner (50), can be adjusted.

[0062] The control of the hydrogen mixing rate in the combustion device (4) for several embodiments will be explained in detail later.

[0063] The first control valve (241), the second control valve (242), the third control valve (243), and the fourth control valve (244) are controlled by a controller configured to control each of these control valves. In some embodiments, this controller is realized by a combustion control device (140) of a gas turbine (1).

[0064] Each processing function of the combustion control device (140) is configured as software (computer program) and executed by a computer, but is not limited thereto and may be configured as hardware.

[0065] (Regarding the water supply)

[0066] A gas turbine (1) according to several embodiments is equipped with a water supply line (215) for supplying cooling water to a pilot combustion burner (50). Although a detailed description is omitted, by supplying cooling water, the flame temperature rising when the hydrogen mixing rate in the pilot combustion burner (50) is increased is suppressed, so NO x Along with suppressing the occurrence of [something], the metal temperature of the cone (56b) of the pilot combustion burner (50) can be suppressed.

[0067] Water for cooling can be supplied to the pilot combustion burner (50) through the water supply line (215) from the water supply source (205).

[0068] A water supply line (215) is provided with a water supply volume control valve (251) for adjusting the amount of water supplied to the pilot combustion burner (50). Although a detailed description is omitted, the water supply volume control valve (251) is controlled by a combustion control device (140).

[0069] (Regarding the control of hydrogen co-firing ratio)

[0070] For example, in facilities that emit carbon dioxide (CO2), which is a cause of global warming, such as gas turbines (1), it is required to reduce the amount of carbon dioxide emitted. For example, in order to reduce the amount of carbon dioxide emitted in gas turbines (1), it is desirable to increase the mixing rate of hydrogen. However, since hydrogen has low ignition energy and a fast combustion rate, increasing the mixing rate of hydrogen increases the likelihood of flame backflow, etc.

[0071] Meanwhile, since the risk of flame backflow (flame flashback) varies depending on the structure of the fuel injector (combustion burner) and its placement, it cannot be said that the risk of flashback is the same for any of the multiple fuel injectors. Specifically, examples are as follows.

[0072] In the embodiments shown in FIGS. 2, 3 and 4, the main combustion burner (60) is a premixed combustion type fuel injector, and the pilot combustion burner (50) is a diffusion combustion type or premixed combustion type fuel injector.

[0073] Generally, a diffusion combustion type fuel injector is a fuel injector with a lower risk of flashback than a premixed combustion type fuel injector. Accordingly, in the embodiment shown in FIGS. 2, FIGS. 3 and FIGS. 4, the pilot combustion burner (50) is a fuel injector with a lower risk of flashback than the main combustion burner (60).

[0074] In addition, generally, when a fuel injector is surrounded by multiple other fuel injectors, the risk of flashback is lower for the surrounding fuel injectors than for the surrounding fuel injectors.

[0075] Here, in the embodiment shown in FIGS. 2, 3 and 4, the main combustion burner (60) is arranged in multiple units around the pilot combustion burner (50). Accordingly, if the structure of the fuel injector in the main combustion burner (60) and the pilot combustion burner (50) is the same, such as when the main combustion burner (60) and the pilot combustion burner (50) are both diffusion combustion or premixed combustion fuel injectors in the embodiment shown in FIGS. 2, 3 and 4, the pilot combustion burner (50) becomes a fuel injector with a lower risk of flashback than the main combustion burner (60).

[0076] Accordingly, in the method of operating a gas turbine according to several embodiments, the gas turbine (1) is operated as follows, taking these into consideration.

[0077] As described above, since the pilot combustion burner (50) is a fuel injector with a lower risk of flashback than the main combustion burner (60), the upper limit value (Crpmax) of the hydrogen mixing rate (Crp) in the pilot combustion burner (50) is made larger than the upper limit value (Crmmax) of the hydrogen mixing rate (Crm) in the main combustion burner (60). By doing so, the maximum value (Cromax) of the hydrogen mixing rate (Cro) in the entire combustion unit (4) can be increased while suppressing flashback.

[0078] More specifically, in a combustion device (4) according to several embodiments, the hydrogen mixing rate is controlled as follows.

[0079] Additionally, the hydrogen mixing ratio (Cro) in the entire combustion unit (4) is expressed as a caloric ratio of the total hydrogen fuel (FH) to the total fuel (F) injected from a plurality of main combustion burners (60) and a pilot combustion burner (50) in one combustion unit.

[0080] FIG. 6a is a graph showing an example of the relationship between the hydrogen mixing rate (Crm, Crp) of each combustion burner and the hydrogen mixing rate (Cro) of the entire combustion unit (4) during rated operation.

[0081] FIG. 6b is a graph showing an example of the relationship between the hydrogen mixing rate (Crm, Crp) of each combustion burner and the hydrogen mixing rate (Cro) of the entire combustion unit (4), and the ratio (Crp / Crm) of the hydrogen mixing rate (Crp) of the pilot combustion burner (50) to the hydrogen mixing rate (Crm) of the main combustion burner (60), when the relationship shown in FIG. 6a is such that the hydrogen mixing rate (Crm, Crp) of each combustion burner and the hydrogen mixing rate (Cro) of the entire combustion unit (4) are the same.

[0082] FIG. 7a is a graph showing another example of the relationship between the hydrogen mixing rate (Crm, Crp) of each combustion burner and the hydrogen mixing rate (Cro) of the entire combustion unit (4) during rated operation.

[0083] FIG. 7b is a graph showing an example of the relationship between the hydrogen mixing rate (Crm, Crp) of each combustion burner and the hydrogen mixing rate (Cro) of the entire combustion unit (4), and the ratio (Crp / Crm) of the hydrogen mixing rate (Crp) of the pilot combustion burner (50) to the hydrogen mixing rate (Crm) of the main combustion burner (60), when the relationship shown in FIG. 7a is such that the hydrogen mixing rate (Crm, Crp) of each combustion burner and the hydrogen mixing rate (Cro) of the entire combustion unit (4) are the same.

[0084] FIG. 8a is a graph showing another example of the relationship between the hydrogen mixing rate (Crm, Crp) of each combustion burner and the hydrogen mixing rate (Cro) of the entire combustion unit (4) during rated operation.

[0085] FIG. 8b is a graph showing an example of the relationship between the hydrogen mixing rate (Crm, Crp) of each combustion burner and the hydrogen mixing rate (Cro) of the entire combustion unit (4), and the ratio (Crp / Crm) of the hydrogen mixing rate (Crp) of the pilot combustion burner (50) to the hydrogen mixing rate (Crm) of the main combustion burner (60), when the relationship shown in FIG. 8a is such that the hydrogen mixing rate (Crm, Crp) of each combustion burner and the hydrogen mixing rate (Cro) of the entire combustion unit (4) are the same.

[0086] FIG. 9a is a graph showing an example of the relationship between the hydrogen mixing rate (Crm, Crp) of each combustion burner and the hydrogen mixing rate (Cro) of the entire combustion unit (4) during partial load operation.

[0087] FIG. 9b is a graph showing an example of the relationship between the hydrogen mixing rate (Crm, Crp) of each combustion burner and the hydrogen mixing rate (Cro) of the entire combustion unit (4), and the ratio (Crp / Crm) of the hydrogen mixing rate (Crp) of the pilot combustion burner (50) to the hydrogen mixing rate (Crm) of the main combustion burner (60), when the relationship shown in FIG. 9a is such that the hydrogen mixing rate (Crm, Crp) of each combustion burner and the hydrogen mixing rate (Cro) of the entire combustion unit (4) are the same.

[0088] For example, consider the case of burning by gradually increasing the hydrogen mixing rate (Cro) from total combustion (hydrogen mixing rate (Cro) = 0%) with natural gas fuel (FN) during rated operation of a gas turbine (1).

[0089] In this case, as shown in FIG. 6a, when operating at a low hydrogen mixing rate where the hydrogen mixing rate (Cro) in the entire combustor (4) is relatively low, as the hydrogen mixing rate (Cro) in the entire combustor (4) increases, the hydrogen mixing rate (Crm, Crp) of each combustion burner may be gradually increased while taking the same value.

[0090] The trend of the hydrogen mixing rate (Crm, Crp) of each combustion burner can be realized by, for example, closing the fourth control valve (244) for controlling the amount of hydrogen fuel (FH) supplied to the pilot combustion burner (50) shown in FIG. 5, and gradually opening the third control valve (243) for controlling the amount of hydrogen fuel (FH) supplied to the main combustion burner (60) and the pilot combustion burner (50).

[0091] Additionally, the combustion control device (140) can transmit a control signal to the third control valve (243) so that the third control valve (243) operates in this manner.

[0092] As shown in FIG. 6a, after gradually increasing the hydrogen mixing ratio (Crm, Crp) of each combustion burner while taking the same value, once the hydrogen mixing ratio (Crm) in the main combustion burner (60) reaches the upper limit value (Crmmax), the hydrogen mixing ratio (Crp) in the pilot combustion burner (50) may be increased so that the hydrogen mixing ratio (Cro) in the entire combustion unit (4) increases. That is, when operating at a high hydrogen mixing ratio, which is higher than when operating at a low hydrogen mixing ratio, the hydrogen mixing ratio (Cro) in the entire combustion unit (4) may be increased by gradually increasing the hydrogen mixing ratio (Crp) in the pilot combustion burner (50).

[0093] The trend of the hydrogen mixing rate (Crm, Crp) of each combustion burner can be realized, for example, by fixing the opening of the third control valve (243) shown in FIG. 5, while gradually closing the second control valve (242) of the second supply line (212), and also gradually opening the fourth control valve (244).

[0094] Additionally, the combustion control device (140) may transmit a control signal to the second control valve (242) and the fourth control valve (244) so ​​that the second control valve (242) and the fourth control valve (244) operate in this manner.

[0095] In addition, the upper limit value (Crpmax) of the hydrogen mixing rate (Crp) in the pilot combustion burner (50) may be 100%, as shown in FIG. 6a and FIG. 7a, FIG. 8a, and FIG. 9a described later.

[0096] For convenience of explanation, the hydrogen mixing rate (Crm, Crp) of each combustion burner is increased while taking the same value, and when the hydrogen mixing rate (Crm) in the main combustion burner (60) reaches the upper limit value (Crmmax), the hydrogen mixing rate (Cro) in the entire combustion unit (4) is defined by the value th1 or the value th3 described later. When the hydrogen mixing rate (Cro) is less than or equal to the value th1 or the value th3, it is referred to as low hydrogen mixing rate operation, and when the hydrogen mixing rate (Cro) exceeds the value th1 or the value th3, it is referred to as high hydrogen mixing rate operation.

[0097] As shown in FIG. 6a, when the hydrogen mixing ratio (Crm, Crp) of each combustion burner is changed, as shown in FIG. 6b, when the value of the hydrogen mixing ratio (Cro) is less than or equal to the value th1, the ratio (Crp / Crm) of the hydrogen mixing ratio (Crp) in the pilot combustion burner (50) to the hydrogen mixing ratio (Crm) in the main combustion burner (60) becomes 1.

[0098] As shown in FIG. 6a, when the hydrogen mixing ratio (Crm, Crp) of each combustion burner is changed, as shown in FIG. 6b, when the value of the hydrogen mixing ratio (Cro) exceeds the value th1, the ratio (Crp / Crm) exceeds 1 and increases as the hydrogen mixing ratio (Cro) increases.

[0099] In the following description, the above ratio (Crp / Crm) during low-hydrogen co-firing operation is referred to as the first ratio (R1), and the above ratio (Crp / Crm) during high-hydrogen co-firing operation is referred to as the second ratio (R2).

[0100] In the example shown in FIGS. 6a and 6b, the fourth control valve (244) for adjusting the supply amount of hydrogen fuel (FH) to the pilot combustion burner (50) was kept closed until the hydrogen mixing rate (Cro) in the main combustion burner (60) reached the upper limit (Crmmax) during the process of increasing the hydrogen mixing rate (Cro) in the entire combustion unit (4). However, the fourth control valve (244) may be opened before the hydrogen mixing rate (Crm) in the main combustion burner (60) reached the upper limit (Crmmax) during the process of increasing the hydrogen mixing rate (Cro) in the entire combustion unit (4).

[0101] The example shown in FIGS. 7a and 7b is that, in the process of increasing the hydrogen co-firing rate (Cro) throughout the combustor (4), the hydrogen co-firing rate (Crm) in the main combustion burner (60) is a value th2 (th2) smaller than the value th1. <th1)에 도달했을 때부터 제4 조절 밸브(244)를 개방하기 시작한 경우의 일례이다.

[0102] In the example shown in FIG. 7a, during the process of increasing the hydrogen mixing rate (Cro) in the entire combustor (4), until the hydrogen mixing rate (Cro) in the entire combustor (4) reaches the value th2, the hydrogen mixing rate (Crm, Crp) of each combustion burner increases while taking the same value as the hydrogen mixing rate (Cro) in the entire combustor (4) increases.

[0103] In the example shown in FIG. 7a, after the hydrogen mixing rate (Cro) in the entire combustor (4) reaches a value th2, until the hydrogen mixing rate (Cro) in the entire combustor (4) reaches a value th1, the hydrogen mixing rate (Crp) in the pilot combustion burner (50) takes a value greater than the hydrogen mixing rate (Crm) in the main combustion burner (60), and as the hydrogen mixing rate (Cro) in the entire combustor (4) increases, the difference between the two gradually increases.

[0104] In the example shown in FIG. 7a, during the process of increasing the hydrogen mixing rate (Cro) throughout the combustor (4), after the hydrogen mixing rate (Cro) throughout the combustor (4) reaches a value th1, the hydrogen mixing rate (Crm) in the main combustion burner (60) becomes an upper limit value (Crmmax), and the hydrogen mixing rate (Crp) in the pilot combustion burner (50) increases. That is, in the example shown in FIG. 7a, during the process of increasing the hydrogen mixing rate (Cro) throughout the combustor (4), after the hydrogen mixing rate (Cro) throughout the combustor (4) reaches a value th1, for example, while keeping the opening of the third control valve (243) shown in FIG. 5 fixed, the second control valve (242) of the second supply line (212) is slowly closed, and the fourth control valve (244) is also slowly opened.

[0105] As shown in FIG. 7a, when the hydrogen mixing ratio (Crm, Crp) of each combustion burner is changed, as shown in FIG. 7b, when the value of the hydrogen mixing ratio (Cro) is less than or equal to the value th2, the ratio (Crp / Crm) of the hydrogen mixing ratio (Crp) in the pilot combustion burner (50) to the hydrogen mixing ratio (Crm) in the main combustion burner (60) becomes 1.

[0106] As shown in Fig. 7a, when the hydrogen mixing ratio (Crm, Crp) of each combustion burner is changed, as shown in Fig. 7b, when the value of the hydrogen mixing ratio (Cro) exceeds the value th2, the ratio (Crp / Crm) exceeds 1 and increases as the hydrogen mixing ratio (Cro) increases.

[0107] In the example shown in FIG. 7a and FIG. 7b, during the process of increasing the hydrogen mixing rate (Cro) throughout the combustor (4), the fourth control valve (244) for adjusting the supply amount of hydrogen fuel (FH) to the pilot combustion burner (50) was kept closed until the hydrogen mixing rate (Cro) throughout the combustor (4) reached the value th2. However, during the process of increasing the hydrogen mixing rate (Cro) throughout the combustor (4), the fourth control valve (244) may be opened at the same time as the third control valve (243) begins to open.

[0108] The example shown in FIGS. 8a and 8b is an example of a case where, in the process of increasing the hydrogen mixing rate (Cro) throughout the combustor (4), the third control valve (243) is opened and the fourth control valve (244) is opened at the same time.

[0109] In the example shown in FIG. 8a, during the process of increasing the hydrogen mixing rate (Cro) in the entire combustion chamber (4), until the hydrogen mixing rate (Cro) in the entire combustion chamber (4) reaches a value th1, the hydrogen mixing rate (Crp) in the pilot combustion burner (50) takes a value greater than the hydrogen mixing rate (Crm) in the main combustion burner (60), and as the hydrogen mixing rate (Cro) in the entire combustion chamber (4) increases, the difference between the two gradually increases.

[0110] In the example shown in FIG. 8a, during the process of increasing the hydrogen mixing rate (Cro) throughout the combustor (4), after the hydrogen mixing rate (Cro) throughout the combustor (4) reaches a value th1, the hydrogen mixing rate (Crm) in the main combustion burner (60) becomes an upper limit value (Crmmax), and the hydrogen mixing rate (Crp) in the pilot combustion burner (50) increases. That is, in the example shown in FIG. 8a, during the process of increasing the hydrogen mixing rate (Cro) throughout the combustor (4), after the hydrogen mixing rate (Cro) throughout the combustor (4) reaches a value th1, for example, while keeping the opening of the third control valve (243) shown in FIG. 5 fixed, the second control valve (242) of the second supply line (212) is slowly closed, and the fourth control valve (244) is also slowly opened.

[0111] As shown in FIG. 8a, when the hydrogen mixing ratio (Crm, Crp) of each combustion burner is changed, as shown in FIG. 8b, the ratio (Crp / Crm) of the hydrogen mixing ratio (Crm) in the pilot combustion burner (50) to the hydrogen mixing ratio (Crm) in the main combustion burner (60) exceeds 1 and increases as the hydrogen mixing ratio (Cro) in the entire combustion unit (4) increases.

[0112] (In the case of partial load operation)

[0113] Generally, as the load of the gas turbine (1) increases, the supply amount of fuel (F) increases, so the risk of flashback increases. Conversely, when the gas turbine (1) is operated at a partial load, the risk of flashback of hydrogen fuel is lower than when operated at a rated load, so the maximum value (Cromax) of the hydrogen mixing rate (Cro) in the entire combustor (4) during partial load operation can be made larger than during rated operation.

[0114] As described above, since the upper limit value (Crpmax) of the hydrogen mixing rate (Crp) in the pilot combustion burner (50) is 100% during rated operation as shown in FIG. 6a, FIG. 7a, and FIG. 8a, there is no room to raise the upper limit value (Crpmax) of the hydrogen mixing rate (Crp) in the pilot combustion burner (50).

[0115] Accordingly, in the method of operating a gas turbine according to several embodiments, as shown in FIG. 9a and FIG. 9b, the upper limit (Crmmax) of the hydrogen mixing rate (Crm) in the main combustion burner (60) during partial load operation is made larger than during rated operation, thereby making the maximum value (Cromax) of the hydrogen mixing rate (Cro) in the entire combustor (4) during partial load operation larger than during rated operation.

[0116] That is, in the operation method of a gas turbine according to several embodiments, as is clear from the comparison of FIG. 9a and, for example, FIG. 6a, the upper limit value (Crmmax) of the hydrogen mixing rate (Crm) in the main combustion burner (60) during partial load operation is made larger than during rated operation.

[0117] For example, consider the case of co-firing while gradually increasing the hydrogen co-firing rate (Cro) from the total combustion of natural gas fuel (FN) (hydrogen co-firing rate (Cro) = 0%) during partial load operation of the gas turbine (1).

[0118] In this case, as shown in FIG. 9a, when operating at a low hydrogen mixing rate where the hydrogen mixing rate (Cro) in the entire combustor (4) is relatively low, as the hydrogen mixing rate (Cro) in the entire combustor (4) increases, the hydrogen mixing rate (Crm, Crp) of each combustion burner may be increased while taking the same value.

[0119] As shown in FIG. 9a, after gradually increasing the hydrogen mixing ratio (Crm, Crp) of each combustion burner while taking the same value, once the hydrogen mixing ratio (Crm) in the main combustion burner (60) reaches the upper limit value (Crmmax), the hydrogen mixing ratio (Crp) in the pilot combustion burner (50) may be increased so that the hydrogen mixing ratio (Cro) in the entire combustion unit (4) increases. That is, when operating at a high hydrogen mixing ratio, which is higher than when operating at a low hydrogen mixing ratio, the hydrogen mixing ratio (Cro) in the entire combustion unit (4) may be increased by gradually increasing the hydrogen mixing ratio (Crp) in the pilot combustion burner (50).

[0120] In the example shown in FIG. 9a, during the process of increasing the hydrogen mixing rate (Cro) throughout the combustor (4), after the hydrogen mixing rate (Cro) throughout the combustor (4) reaches the value th3, the second control valve (242) of the second supply line (212) is slowly closed while the opening of the third control valve (243) shown in FIG. 5 is fixed, for example, and the fourth control valve (244) is also slowly opened.

[0121] As shown in FIG. 9a, when the hydrogen mixing ratio (Crm, Crp) of each combustion burner is changed, as shown in FIG. 9b, when the value of the hydrogen mixing ratio (Cro) is less than or equal to the value th3 (when operating at a low hydrogen mixing ratio), the ratio (Crp / Crm) of the hydrogen mixing ratio (Crm) in the pilot combustion burner (50) to the hydrogen mixing ratio (Crm) in the main combustion burner (60) becomes 1.

[0122] As shown in FIG. 9a, when the hydrogen mixing ratio (Crm, Crp) of each combustion burner is changed, as shown in FIG. 9b, when the value of the hydrogen mixing ratio (Cro) exceeds the value th3 (when operating at a high hydrogen mixing ratio), the above ratio (Crp / Crm) exceeds 1 and increases as the hydrogen mixing ratio (Cro) increases.

[0123] Additionally, as the gas turbine inlet combustion gas temperature (T1T) decreases, the upper limit (Crmmax) of the hydrogen mixing rate (Crm) in the main combustion burner (60) may be increased.

[0124] (Summary of operating methods of gas turbines regarding several embodiments)

[0125] The contents described in each of the above embodiments are summarized below.

[0126] A method of operating a gas turbine according to several embodiments is a method of operating a gas turbine (1) having a main nozzle (64) and a pilot nozzle (54), and a combustor (4) capable of using hydrogen and a fuel other than hydrogen as fuel. The ratio (Crp / Crm) of the hydrogen mixing rate (Crp) of the fuel (F) injected from the pilot nozzle (54) to the hydrogen mixing rate (Crm) of the fuel (F) injected from the main nozzle (64) is such that, as shown in FIG. 6b, FIG. 7b, FIG. 8b, and FIG. 9b, the second ratio (R2) of the high hydrogen mixing rate operation, in which the hydrogen mixing rate (Cro) in the entire combustor (4) is higher than in the low hydrogen mixing rate operation, is greater than the first ratio (R1) of the low hydrogen mixing rate operation.

[0127] For example, if the pilot combustion burner (50) is less likely to cause backflow of flame than the main combustion burner (60), the risk of flashback can be reduced by increasing the hydrogen mixing rate (Cro) of the fuel (F) injected from the pilot combustion burner (50) more than the hydrogen mixing rate (Crm) of the fuel (F) injected from the main combustion burner (60).

[0128] According to the operation method of a gas turbine in some embodiments, if the pilot combustion burner (50) is less prone to flashback than the main combustion burner (60), it can be operated at a high hydrogen mixing rate (Cro) while suppressing flashback.

[0129] In the method of operating a gas turbine according to several embodiments, as shown in FIGS. 6b, FIGS. 7b, FIGS. 8b, and FIGS. 9b, the second ratio (R2) increases as the hydrogen mixing ratio of the fuel (F) supplied to the combustor (4) (hydrogen mixing ratio (Cro) in the entire combustor (4)) increases.

[0130] Thus, when operating at a high hydrogen mixing rate, the hydrogen mixing rate (Crm) of the main combustion burner (60) is suppressed to suppress flashback, and the hydrogen mixing rate (Crp) of the pilot combustion burner (50) is increased, thereby increasing the hydrogen mixing rate (Cro) in the entire combustion unit (4).

[0131] In a method of operating a gas turbine according to several embodiments, as shown in FIGS. 6a, 7a, 8a, and 9a, when operating at a high hydrogen mixing rate, as the hydrogen mixing rate of the fuel (F) supplied to the combustor (4) (hydrogen mixing rate (Cro) in the entire combustor (4)) increases, the hydrogen mixing rate (Crp) of the fuel (F) injected from the pilot combustion burner (50) should increase.

[0132] Thus, when operating at a high hydrogen mixing rate, the hydrogen mixing rate (Crp) of the pilot combustion burner (50) can be increased to suppress flashback while increasing the hydrogen mixing rate (Cro) throughout the combustion unit (4).

[0133] In a method of operating a gas turbine according to several embodiments, as shown in FIGS. 6a, 7a, 8a, and 9a, when operating at a high hydrogen mixing rate, the increase rate of the hydrogen mixing rate (Crp) of the fuel (F) injected from the pilot combustion burner (50) relative to the increase rate of the hydrogen mixing rate (Cro) of the fuel (F) supplied to the combustor (4) is greater than the increase rate of the hydrogen mixing rate (Crm) of the fuel (F) injected from the main combustion burner (60) relative to the increase rate of the hydrogen mixing rate (Cro) of the fuel (F) supplied to the combustor (4).

[0134] In addition, the fact that the growth rate of the hydrogen co-firing rate (Crp) relative to the growth rate of the hydrogen co-firing rate (Cro) is greater than the growth rate of the hydrogen co-firing rate (Crm) relative to the growth rate of the hydrogen co-firing rate (Cro) is equivalent to the fact that the slope of the graph line of the hydrogen co-firing rate (Crp) in FIGS. 6a, FIGS. 7a, FIGS. 8a, and FIGS. 9a is greater than the slope of the graph line of the hydrogen co-firing rate (Crm).

[0135] In a method of operating a gas turbine according to several embodiments, as shown in FIGS. 6a, 7a, 8a, and 9a, when operating at a high hydrogen co-firing rate, that is, when the value of the hydrogen co-firing rate (Cro) exceeds the value th1 or the value th3, the slope of the graph line of the hydrogen co-firing rate (Crp) is greater than the slope of the graph line of the hydrogen co-firing rate (Crm).

[0136] Thus, when operating at a high hydrogen mixing rate, the hydrogen mixing rate (Crm) of the main combustion burner (60) is suppressed to suppress flashback, and the hydrogen mixing rate (Crp) of the pilot combustion burner (50) is increased, thereby increasing the hydrogen mixing rate (Cro) in the entire combustion unit (4).

[0137] In a method of operating a gas turbine according to several embodiments, as shown in FIGS. 6a, 7a, 8a, and 9a, when operating at a high hydrogen mixing rate, the hydrogen mixing rate (Crm) of the fuel (F) injected from the main combustion burner (60) may be a constant value regardless of the hydrogen mixing rate (Cro) of the fuel (F) supplied to the combustor (4).

[0138] Thus, when operating at a high hydrogen mixing rate, the hydrogen mixing rate (Crm) of the main combustion burner (60) is kept constant to suppress flashback, and the hydrogen mixing rate (Crp) of the pilot combustion burner (50) is increased, thereby increasing the hydrogen mixing rate (Cro) in the entire combustion unit (4).

[0139] In a method of operating a gas turbine according to several embodiments, as shown in FIGS. 6a, FIGS. 7a, FIGS. 8a, and FIGS. 9a, the upper limit value (Crmmax) of the hydrogen mixing rate (Crp) of the fuel (F) injected from the pilot combustion burner (50) is 100%.

[0140] Thus, the hydrogen mixing rate (Crp) of the pilot combustion burner (50) can be set to 100% while suppressing flashback in the combustion unit (4), and the hydrogen mixing rate (Cro) in the entire combustion unit (4) can be increased.

[0141] In a method of operating a gas turbine according to several embodiments, as shown in FIG. 6a, FIG. 7a, and FIG. 9a, for at least a portion of the period during low hydrogen co-firing rate operation, the first ratio (R1) is 1.

[0142] Thus, since the hydrogen mixing rate (Crm) of the fuel (F) injected from the main combustion burner (60) and the hydrogen mixing rate (Crp) of the fuel (F) injected from the pilot combustion burner (50) are the same, the fuel (F) supply system (200) for the main combustion burner (60) and the pilot combustion burner (50) can be shared as shown in FIG. 5, so the fuel (F) supply system (200) can be simplified.

[0143] In a method of operating a gas turbine according to several embodiments, as shown in FIG. 6a and FIG. 9a, the upper limit value (Crmmax) of the hydrogen mixing rate (Crm) of the fuel (F) injected from the main combustion burner (60) should be greater during partial load operation than during rated operation of the gas turbine (1).

[0144] Since the risk of backfire of hydrogen fuel (FH) is lower during partial load operation of the gas turbine (1) than during rated operation, the maximum value (Cromax) of the hydrogen mixing rate (Cro) in the entire combustor (4) during partial load operation can be made larger than during rated operation. According to the operation method of the gas turbine according to several embodiments, by making the upper limit value (Crmmax) of the hydrogen mixing rate (Crm) of the main combustion burner (60) during partial load operation larger than during rated operation, the maximum value (Cromax) of the overall hydrogen mixing rate (hydrogen mixing rate (Cro) in the entire combustor (4)) during partial load operation can be made larger than during rated operation.

[0145] In addition, according to the operating method of a gas turbine in some embodiments, the hydrogen mixing rate (Crp) in the pilot combustion burner (50) becomes 100%, and even if the hydrogen mixing rate (Crp) in the pilot combustion burner (50) cannot be increased further, the hydrogen mixing rate (Cro) in the entire combustion unit (4) can be increased.

[0146] In a method of operating a gas turbine according to several embodiments, as shown in FIGS. 2, 3, and 4, the combustor (4) may be provided with a main combustion burner (60) having a main nozzle (64) and a pilot combustion burner (50) having a pilot nozzle (54). The main combustion burner (60) may be a premixed combustion type burner, and the pilot combustion burner (50) may be a diffusion combustion type burner.

[0147] Thus, since the risk of flashback is lower in the diffusion combustion type burner than in the premixed combustion type burner, the upper limit (Crmmax) of the hydrogen mixing rate (Crp) of the pilot combustion burner (50) can be increased, and the overall hydrogen mixing rate (hydrogen mixing rate (Cro) in the entire combustion chamber (4)) can be increased.

[0148] In a method of operating a gas turbine according to several embodiments, the pilot combustion burner (50) may be configured to have a water flow path and be capable of spraying water.

[0149] Thus, by suppressing the flame temperature, NO x It is possible to suppress the metal temperature of the pilot combustion burner (50) (cone (56b)).

[0150] The present disclosure is not limited to the embodiments described above, but also includes forms with modifications to the embodiments described above, or forms appropriately combined thereof.

[0151] For example, in the method of operating a gas turbine according to the above-described embodiments, in at least some range of hydrogen mixing rates (Cro) where the value of the hydrogen mixing rate (Cro) is less than or equal to the value th1 or the value th3, the ratio (Crp / Crm) of the hydrogen mixing rate (Crp) in the pilot combustion burner (50) to the hydrogen mixing rate (Crm) in the main combustion burner (60) may be less than 1.

[0152] The contents described in each of the above embodiments are understood, for example, as follows.

[0153] (1) A method of operating a gas turbine (1) according to at least one embodiment of the present disclosure is a method of operating a gas turbine (1) having a main nozzle (64) and a pilot nozzle (54), and a combustor (4) capable of using hydrogen and a fuel other than hydrogen as fuel. The ratio (Crp / Crm) of the hydrogen mixing rate (Crp) of the fuel (F) injected from the pilot nozzle (54) to the hydrogen mixing rate (Crm) of the fuel (F) injected from the main nozzle (64) is such that, compared to the first ratio (R1) during low hydrogen mixing rate operation, the second ratio (R2) during high hydrogen mixing rate operation, where the hydrogen mixing rate (Cro) is higher than during low hydrogen mixing rate operation, is greater.

[0154] For example, if the pilot nozzle (54) is less likely to cause backfire than the main nozzle (64), the risk of backfire can be reduced by increasing the hydrogen mixing rate (Cro) of the fuel (F) injected from the pilot nozzle (54) more than the hydrogen mixing rate (Crm) of the fuel (F) injected from the main nozzle (64).

[0155] According to the method of (1) above, if the pilot nozzle (54) is less likely to cause flame backflow than the main nozzle (64), it can be operated at a high hydrogen mixing rate (Cro) while suppressing flashback.

[0156] (2) In some embodiments, in the method of (1) above, the second ratio (R2) increases as the hydrogen mixing ratio (Cro) of the fuel (F) supplied to the combustor (4) increases.

[0157] According to the method of (2) above, when operating at a high hydrogen mixing rate, the hydrogen mixing rate (Crm) of the main nozzle (64) is suppressed to suppress flashback, and the hydrogen mixing rate (Crp) of the pilot nozzle (54) is increased, thereby increasing the hydrogen mixing rate (Cro) in the entire combustor (4).

[0158] (3) In some embodiments, in the method of (2) above, when operating at a high hydrogen mixing rate, as the hydrogen mixing rate (Cro) of the fuel (F) supplied to the combustor (4) increases, the hydrogen mixing rate (Crp) of the fuel (F) injected from the pilot nozzle (54) increases.

[0159] According to the method of (3) above, when operating at a high hydrogen mixing rate, the hydrogen mixing rate (Crp) of the pilot nozzle (54) can be increased to suppress flashback while increasing the hydrogen mixing rate (Cro) throughout the combustor (4).

[0160] (4) In some embodiments, when operating at a high hydrogen mixing rate in the method of (2) or (3), the increase rate of the hydrogen mixing rate (Crp) of the fuel (F) injected from the pilot nozzle (54) relative to the increase rate of the hydrogen mixing rate (Cro) of the fuel (F) supplied to the combustor (4) is greater than the increase rate of the hydrogen mixing rate (Crm) of the fuel (F) injected from the main nozzle (64) relative to the increase rate of the hydrogen mixing rate (Cro) of the fuel (F) supplied to the combustor (4).

[0161] According to the method of (4) above, when operating at a high hydrogen mixing rate, the hydrogen mixing rate (Crm) of the main nozzle (64) is suppressed to suppress flashback, and the hydrogen mixing rate (Crp) of the pilot nozzle (54) is increased, thereby increasing the hydrogen mixing rate (Cro) in the entire combustor (4).

[0162] (5) In some embodiments, when operating at a high hydrogen mixing rate in the method of (4) above, the hydrogen mixing rate (Crm) of the fuel (F) injected from the main nozzle (64) may be a constant value regardless of the hydrogen mixing rate (Cro) of the fuel (F) supplied to the combustor (4).

[0163] According to the method of (5) above, when operating at a high hydrogen mixing rate, the hydrogen mixing rate (Crm) of the main nozzle (64) is kept constant to suppress flashback, and the hydrogen mixing rate (Crp) of the pilot nozzle (54) is increased, thereby increasing the hydrogen mixing rate (Cro) in the entire combustor (4).

[0164] (6) In some embodiments, in any one of the methods (1) to (5) above, the upper limit (Crmmax) of the hydrogen mixing rate (Crp) of the fuel (F) injected from the pilot nozzle (54) is 100%.

[0165] According to the method of (6) above, the hydrogen mixing rate (Crp) of the pilot nozzle (54) can be increased to 100% while suppressing flashback in the combustor (4), and the hydrogen mixing rate (Cro) in the entire combustor (4) can be increased.

[0166] (7) In some embodiments, in any one of the methods (1) to (6) above, the first ratio (R1) is 1 during at least a portion of the period of operation of the low hydrogen co-firing rate.

[0167] According to the method of (7) above, since the hydrogen mixing rate (Crm) of the fuel (F) injected from the main nozzle (64) and the hydrogen mixing rate (Crp) of the fuel (F) injected from the pilot nozzle (54) are the same, the fuel (F) supply system (200) to the main nozzle (64) and the pilot nozzle (54) can be shared, so the fuel (F) supply system (200) can be simplified.

[0168] (8) In some embodiments, in any one of the methods (1) to (7) above, the upper limit (Crmmax) of the hydrogen mixing rate (Crm) of the fuel (F) injected from the main nozzle (64) should be greater during partial load operation than during rated operation of the gas turbine (1).

[0169] Since the risk of backfire of hydrogen fuel (FH) is lower during partial load operation of the gas turbine (1) than during rated operation, the maximum value (Cromax) of the hydrogen mixing rate (Cro) in the entire combustor (4) during partial load operation can be made larger than during rated operation. According to the method of (8) above, by making the upper limit value (Crmmax) of the hydrogen mixing rate (Crm) of the main nozzle (64) during partial load operation larger than during rated operation, the maximum value (Cromax) of the overall hydrogen mixing rate (Cro) during partial load operation can be made larger than during rated operation.

[0170] (9) In some embodiments, in any one of the methods (1) to (8) above, the combustor (4) may be provided with a main combustion burner (60) having a main nozzle (64) and a pilot combustion burner (50) having a pilot nozzle (54). The main combustion burner (60) may be a premixed combustion type burner, and the pilot combustion burner (50) may be a diffusion combustion type burner.

[0171] According to the method of (9) above, since the risk of flashback is lower in the diffusion combustion type burner than in the premixed combustion type burner, the upper limit value (Crpmax) of the hydrogen mixing rate (Crp) of the pilot combustion burner (50) can be increased, and the overall hydrogen mixing rate (Cro) can be increased.

[0172] (10) In some embodiments, in any one of the methods (1) to (9) above, the pilot nozzle (54) may have a water flow path and be configured to spray water.

[0173] According to the method of (10) above, the flame temperature is suppressed so that NO x It is possible to suppress the metal temperature of the pilot combustion burner (50) (cone (56b)). Explanation of the symbols

[0174] 1 Gas turbine 4 Gas turbine combustor (combustor) 50 pilot combustion burners 54 pilot nozzles 60 main combustion burner 64 main nozzles 200 supply system

Claims

Claim 1 A method of operating a gas turbine having a main nozzle and a pilot nozzle, and a combustor capable of using hydrogen and a fuel other than hydrogen as fuel, wherein the ratio of the hydrogen mixing rate of the fuel injected from the pilot nozzle to the hydrogen mixing rate of the fuel injected from the main nozzle is such that, compared to the first ratio during low hydrogen mixing rate operation, the second ratio during high hydrogen mixing rate operation, where the hydrogen mixing rate is higher than during low hydrogen mixing rate operation, is greater. Claim 2 A method of operating a gas turbine according to claim 1, wherein the second ratio increases as the hydrogen mixing ratio of the fuel supplied to the combustor increases. Claim 3 A method of operating a gas turbine according to claim 2, wherein, during high-hydrogen co-firing rate operation, the hydrogen co-firing rate of the fuel injected from the pilot nozzle increases as the hydrogen co-firing rate of the fuel supplied to the combustor increases. Claim 4 A method of operating a gas turbine according to claim 2 or claim 3, wherein, during high-hydrogen co-firing rate operation, the increase rate of the hydrogen co-firing rate of the fuel injected from the pilot nozzle relative to the increase rate of the hydrogen co-firing rate of the fuel supplied to the combustor is greater than the increase rate of the hydrogen co-firing rate of the fuel injected from the main nozzle relative to the increase rate of the hydrogen co-firing rate of the fuel supplied to the combustor. Claim 5 A method of operating a gas turbine according to claim 4, wherein, during high hydrogen co-firing rate operation, the hydrogen co-firing rate of the fuel injected from the main nozzle is a constant value regardless of the hydrogen co-firing rate of the fuel supplied to the combustor. Claim 6 A method of operating a gas turbine according to claim 1 or claim 2, wherein the upper limit of the hydrogen co-firing rate of the fuel injected from the pilot nozzle is 100%. Claim 7 A method of operating a gas turbine according to claim 1 or claim 2, wherein the first ratio is 1 for at least a portion of the period during the low hydrogen co-firing rate operation. Claim 8 A method of operating a gas turbine according to claim 1 or claim 2, wherein the upper limit of the hydrogen co-firing rate of the fuel injected from the main nozzle is greater during partial load operation than during rated operation of the gas turbine. Claim 9 A method of operating a gas turbine according to claim 1 or claim 2, wherein the combustor comprises a main combustion burner having the main nozzle and a pilot combustion burner having the pilot nozzle, wherein the main combustion burner is a burner of the premixed combustion type and the pilot combustion burner is a burner of the diffusion combustion type. Claim 10 A method of operating a gas turbine according to claim 1 or claim 2, wherein the pilot nozzle has a water flow path and is configured to be able to spray the water.

Images