Gas turbine control device and gas turbine control method

Abstract

It suppresses combustion vibrations during mixed combustion of multiple types of fuels. [Solution] This application relates to a gas turbine control device for controlling a gas turbine capable of co-firing a first fuel and a second fuel. The gas turbine control device calculates an index corresponding to the turbine inlet temperature during pure-fire operation of the first fuel, based on the operating parameters of the gas turbine. This index is corrected using a correction coefficient based on the co-firing ratio, which indicates the proportion of the second fuel to the total fuel. The gas turbine is controlled based on the corrected index.

Description

Technical Field

[0001] The present disclosure relates to a gas turbine control device and a gas turbine control method.

Background Art

[0002] There is known a gas turbine that obtains power by driving a turbine using combustion gas generated by combustion of fuel. As one of the control parameters for controlling the operating state of this type of gas turbine, there is the combustion gas temperature at the inlet of the turbine (hereinafter, appropriately referred to as "turbine inlet temperature"). The turbine inlet temperature is a parameter that more accurately indicates the operating state of the gas turbine compared to the load of the gas turbine.

[0003] In recent gas turbines, the gas turbine inlet temperature has been increasing, and it has become difficult to measure it as an actual measurement value over a long period of time. Therefore, in Patent Document 1, gas turbine control using an index (CLCSO) obtained by dimensionlessizing the turbine inlet temperature as an alternative parameter for such a turbine inlet temperature is disclosed. In this document, a parameter having a positive correlation with the turbine inlet temperature (proportional to the turbine inlet temperature) is used, and an index defined such that it becomes 0% when the turbine inlet temperature is the lower limit value and 100% when the turbine inlet temperature is the upper limit value is used.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The index dealt with in Patent Document 1 above is calculated based on gas turbine output as a substitute parameter for turbine inlet temperature when burning only one type of fuel, such as natural gas. In recent years, for example, high-combustibility fuels with relatively high combustion rates, such as hydrogen, are sometimes mixed with natural gas. When multiple types of fuel are mixed in this way, the amount of water contained in the combustion products changes compared to when a single type of fuel is burned exclusively, which changes the specific heat ratio of the combustion products (the ratio of rated specific heat capacity to constant-volume specific heat capacity), and as a result, the gas turbine output corresponding to the same turbine inlet temperature changes. Therefore, when multiple types of fuel are mixed in, controlling the gas turbine based on the same index as when burning exclusively, and applying the same control parameters to different turbine inlet temperatures, may cause combustion vibrations in the gas turbine.

[0006] At least one embodiment of this disclosure has been made in view of the above circumstances and aims to provide a gas turbine control device and a gas turbine control method capable of suppressing combustion vibrations during mixed combustion operation of multiple types of fuels. [Means for solving the problem]

[0007] A gas turbine control device according to at least one embodiment of this disclosure solves the above problems, A gas turbine control device for controlling a gas turbine capable of co-firing a first fuel and a second fuel different from the aforementioned first fuel, An index calculation unit for calculating an index corresponding to the turbine inlet temperature of the gas turbine during dedicated combustion operation of the first fuel, based on at least one operating parameter of the gas turbine, A correction coefficient calculation unit for calculating a correction coefficient based on a co-firing ratio that indicates the proportion of the second fuel to the total fuel supplied to the gas turbine, A correction unit for calculating a corrected index by correcting the aforementioned index using the correction coefficient, A control unit for controlling the gas turbine based on the corrected index, It is equipped with.

[0008] A gas turbine control method according to at least one embodiment of this disclosure solves the above problems. A gas turbine control method for controlling a gas turbine capable of co-firing a first fuel and a second fuel different from the first fuel, A step of calculating an index corresponding to the turbine inlet temperature of the gas turbine during dedicated combustion operation of the first fuel, based on at least one operating parameter of the gas turbine; A step of calculating a correction coefficient based on a co-firing ratio that indicates the ratio of the second fuel to the total fuel supplied to the gas turbine, The process of calculating a corrected index by correcting the aforementioned index using the correction coefficient, A step of controlling the gas turbine based on the corrected index, It is equipped with. [Effects of the Invention]

[0009] According to at least one embodiment of this disclosure, a gas turbine control device and a gas turbine control method capable of suppressing combustion vibrations during mixed combustion operation of multiple types of fuels can be provided. [Brief explanation of the drawing]

[0010] [Figure 1] This is a schematic diagram showing a gas turbine according to one embodiment. [Figure 2] This is a cross-sectional view showing the combustor in Figure 1. [Figure 3] This is a cross-sectional view showing the main parts of the combustor in Figure 2. [Figure 4] Figure 3 schematically shows an example of the arrangement of each fuel injector when viewing the combustor from downstream to upstream along the axial direction of the combustor. [Figure 5] This is a schematic diagram of a gas turbine control device according to one embodiment. [Figure 6] Figure 5 is a block diagram showing the internal configuration of a gas turbine control device. [Figure 7]This is an example of the function of the correction coefficient calculation unit in FIG. 6. [Figure 8] This is a block diagram showing the configuration of the index calculation logic in the index calculation unit of FIG. 6. [Figure 9] This is a block diagram showing the configuration of the control command calculation logic of the control unit in FIG. 6. [Figure 10] This is a diagram showing the relationship between the generator output and the index in the gas turbine controlled by the gas turbine control method according to the comparative example. [Figure 11] This is a diagram showing the relationship between the generator output and the corrected index during the co-firing operation in the gas turbine controlled by the gas turbine control method according to an embodiment.

Embodiments for Carrying Out the Invention

[0011] Hereinafter, some embodiments of the present disclosure will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of the configurations described as embodiments or shown in the drawings are not intended to limit the scope of the present disclosure, but are merely illustrative examples.

[0012] First, the gas turbine 1 which is the control target of the gas turbine control device 100 according to at least one embodiment of the present disclosure will be described. FIG. 1 is a schematic configuration diagram showing the gas turbine 1 according to an embodiment.

[0013] The gas turbine 1 includes a compressor 2 for generating compressed air as an oxidant, a combustor 4 for generating combustion gas using the compressed air and fuel, and a turbine 6 configured to be rotationally driven by the combustion gas. In the case of the 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.

[0014] The compressor 2 comprises a compressor casing 10, an air intake 12 provided on the inlet side of the compressor casing 10 for taking in air, a rotor 8 provided to penetrate both the compressor casing 10 and the turbine casing 22 (described later), and various blades arranged within the compressor casing 10. The various blades include an inlet guide blade 14 provided on the air intake 12 side, a plurality of stationary blades 16 fixed to the compressor casing 10 side, and a plurality of rotor blades 18 planted on the rotor 8 so as to be alternately arranged with respect to the stationary blades 16.

[0015] The compressor 2 may also include other components such as an extraction chamber (not shown). In such a compressor 2, the air taken in from the air intake 12 is compressed by passing through a plurality of stationary blades 16 and a plurality of rotor blades 18 to become high-temperature, high-pressure compressed air. This high-temperature, high-pressure compressed air is then sent from the compressor 2 to the combustor 4 downstream.

[0016] The combustor 4 is located inside the casing 20. As shown in Figure 1, multiple combustors 4 may be arranged in a ring shape around the rotor 8 inside the casing 20. Fuel and compressed air produced by the compressor 2 are supplied to the combustor 4, and by burning the fuel, combustion gas, which is the working fluid for the turbine 6, is generated. The combustion gas is then sent from the combustor 4 to the downstream turbine 6.

[0017] The turbine 6 comprises a turbine casing 22 and various blades arranged within the turbine casing 22. The various blades include a plurality of stator blades 24 fixed to the turbine casing 22 and a plurality of rotor blades 26 mounted on the rotor 8 so as to be alternately arranged with respect to the stator blades 24. The turbine 6 may also include other components such as outlet guide blades. In the turbine 6, the rotor 8 is driven to rotate as combustion gases pass through the plurality of stator blades 24 and the plurality of rotor blades 26. This drives a generator (not shown) connected to the rotor 8.

[0018] Downstream of the turbine casing 22, an exhaust chamber 30 is connected via an exhaust casing 28. Combustion gases after driving the turbine 6 are discharged to the outside through the exhaust casing 28 and exhaust chamber 30.

[0019] Next, the specific configuration of the combustor 4 of the gas turbine 1 will be explained. Figure 2 is a cross-sectional view of the combustor 4 in Figure 1, Figure 3 is a cross-sectional view showing the main part of the combustor 4 in Figure 2, and Figure 4 is a schematic diagram showing an example of the arrangement of each fuel injector when the combustor 4 is viewed from downstream to upstream along the axial direction of the combustor 4 in Figure 3.

[0020] As shown in Figures 2 and 3, the combustor 4 includes a combustor liner 46 provided in a combustor chamber 40 defined by a casing 20 (see Figure 1), and a main fuel injector 41 and a pilot fuel injector 42, respectively, arranged within the combustor liner 46. In the following description, the fuel F injected from the main fuel injector 41 will also be referred to as main fuel Fm, and the fuel F injected from the pilot fuel injector 42 will also be referred to as pilot fuel Fp.

[0021] The combustor 4 further includes an outer cylinder 45 provided on the outer circumference of the inner cylinder 47 of the combustor liner 46 inside the casing 20. An air passage 43 through which compressed air flows is formed on the outer circumference of the inner cylinder 47 and on the inner circumference of the outer cylinder 45. For example, the combustor liner 46 has an inner cylinder 47 arranged around the main fuel injector 41 and pilot fuel injector 42, and a tail cylinder 48 connected to the tip of the inner cylinder 47. That is, the combustor liner 46 defines a combustion region in which the fuel F injected from the main fuel injector 41 and pilot fuel injector 42 is burned.

[0022] As shown in Figure 4, the pilot fuel injector 42 is positioned along the central axis of the combustor liner 46. Multiple main fuel injectors 41 are arranged circumferentially, spaced apart from each other, surrounding the outer circumference of the pilot fuel injector 42.

[0023] As shown in Figure 3, the pilot fuel injector 42 includes a pilot nozzle (nozzle) 54 connected to a fuel port 52, a pilot burner cylinder 56 arranged to surround the pilot nozzle 54, and a plurality of swaras 58 (swivel plates) provided on the outer circumference of the pilot nozzle 54.

[0024] The pilot nozzle 54 extends along the axial direction Da with respect to the combustor axis Ac. Here, one side of the axial direction Da, which is the direction in which the combustor axis Ac extends, is defined as the upstream side along the flow of combustion gases, and the other side, which is the downstream side along the flow of combustion gases, is defined as the downstream side. The combustor axis Ac is also the burner axis of the pilot combustion burner 50.

[0025] An injection hole (not shown) for injecting fuel F (pilot fuel Fp) is formed at the downstream end of the pilot nozzle 54. Upstream of the position where the injection hole is formed in the pilot nozzle 54, a plurality of swirlers 58 are provided. Each swirler 58 is for swirling compressed air around the combustor axis Ac. Each swirler 58 extends from the outer circumference of the pilot nozzle 54 in a direction including a radial component and is close to the inner surface of the pilot burner cylinder 56. The pilot burner cylinder 56 has a main body portion 56a located on the outer circumference of the pilot nozzle 54 and a cone portion 56b connected to the downstream side of the main body portion 56a and gradually widening in diameter toward the downstream side. The plurality of swirlers 58 are close to the inner surface of the main body portion 56a of the pilot burner cylinder 56.

[0026] The main fuel injector 41 includes a main nozzle 64 connected to a fuel port 62, a main burner cylinder 66 arranged to surround the main nozzle 64, an extension pipe 65 connecting the main burner cylinder 66 to the combustor liner 46 (for example, an inner cylinder 47), and a swirler 70 (rotating plate) provided on the outer circumference of the main nozzle 64.

[0027] The main nozzle 64 is a rod-shaped nozzle that extends along the axial direction Da with respect to the burner axis Ab, which is parallel to the combustor axis Ac. Since the burner axis Ab of the main fuel injector 41 is parallel to the combustor axis Ac, the axial direction Da with respect to the combustor axis Ac and the axial direction Da with respect to the burner axis Ab are in the same direction. Furthermore, the upstream side of the axial direction Da with respect to the combustor 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 combustor axis Ac is the downstream side of the axial direction Da with respect to the burner axis Ab.

[0028] An injection hole (not shown) for injecting fuel F (main fuel Fm) is formed in the middle of the main nozzle 64 in the axial direction Da. Multiple swirls 70 are provided near the location where the injection hole is formed in the main nozzle 64. Each swirl 70 is for swirling compressed air around the burner axis Ab. Each swirl 70 extends from the outer circumference of the main nozzle 64 in a direction including the radial component and is close to the inner surface of the main burner cylinder 66. The main burner cylinder 66 is located on the outer circumference of the main nozzle 64.

[0029] In the combustor 4 having the above configuration, compressed air generated by the compressor 2 is introduced into the combustor chamber 40 from the chamber inlet 40a, and further flows from the combustor chamber 40 through the air passage 43 into the pilot burner cylinder 56 and the multiple main burner cylinders 66.

[0030] In the pilot fuel injector 42, pilot fuel Fp, injected from the pilot nozzle 54, is ejected from the downstream end of the pilot burner cylinder 56 along with compressed air. This pilot fuel Fp undergoes diffusion combustion within the combustor liner 46. In other words, the pilot fuel injector 42 is a diffusion combustion type fuel injector.

[0031] In the main fuel injector 41, compressed air and the main fuel Fm injected from the main nozzle 64 are mixed in the main burner cylinder 66 to form a premixed gas PM. In the main fuel injector 41, the premixed gas PM is ejected from the downstream end of the extension pipe 65. The main fuel Fm in this premixed gas PM undergoes premixed combustion in the combustor liner 46. In other words, the main fuel injector 41 is a premixed combustion type fuel injector.

[0032] As shown in Figure 2, the gas turbine 1 has a fuel supply system 80 for supplying fuel F to the combustor 4. The fuel supply system 80 can supply a first fuel F1 and a second fuel F2 as fuel F. The first fuel F1 and the second fuel F2 are different fuels. The second fuel F2 has a higher combustion rate than the first fuel F1. For example, the first fuel F1 is natural gas and the second fuel F2 is hydrogen gas (the second fuel F2 may be propane or a mixture of hydrogen and propane).

[0033] The fuel supply system 80 includes a first fuel supply line 82 that guides the first fuel F1 supplied from a first fuel supply source 81, and a second fuel supply line 84 that guides the second fuel F2 supplied from a second fuel supply source 83. The first fuel supply line 82 is equipped with a first flow meter FR1 for measuring the flow rate of the first fuel F1 flowing through the first fuel supply line 82 (hereinafter referred to as "first fuel flow rate" as appropriate). The second fuel supply line 84 is equipped with a flow control valve V1 for adjusting the flow rate of the second fuel F2 in the second fuel supply line 84 (hereinafter referred to as "second fuel flow rate" as appropriate), and a second flow meter FR2 for measuring the second fuel flow rate, in order from the upstream side. These first fuel supply line 82 and second fuel supply line 84 merge downstream of each other and are connected to the respective fuel ports 52 and 62 of the combustor 4 via the main fuel supply line 85.

[0034] The main fuel supply line 85 branches downstream into branch lines 85a and 85b. Branch lines 85a and 85b are connected to the fuel port 52 of the pilot fuel injector 42 and the fuel port 62 of the main fuel injector 41, respectively. Of the fuel F flowing through the main fuel supply line 85, the portion supplied to the fuel port 52 of the pilot fuel injector 42 via branch line 85a becomes pilot fuel Fp. Also, of the fuel F flowing through the main fuel supply line 85, the portion supplied to the fuel port 62 of the main fuel injector 41 via branch line 85b becomes main fuel Fm.

[0035] Furthermore, the branch lines 85a and 85b are provided with flow control valves V3 and V4, respectively, for adjusting the flow rates of pilot fuel Fp and main fuel Fm. The flow control valves V3 and V4 function as operating terminals for realizing fuel distribution control to the main fuel injector 41 and pilot fuel injector 42, by controlling their respective opening degrees based on control commands from the gas turbine control device 100 described later.

[0036] In such a fuel supply system 80, the supply flow rates of the first fuel F1 and the second fuel F2 to the combustor 4 can be adjusted independently of each other. The co-firing ratio γ, which represents the ratio of the second fuel F2 to the total fuel (fuel F), is defined by the following equation, using the first fuel flow rate measured by the first flow meter FR1 and the second fuel flow rate measured by the second flow meter FR2. Mixed combustion ratio γ = 2nd fuel flow rate / (1st fuel flow rate + 2nd fuel flow rate) × 100 (1)

[0037] For example, if the flow rate of the second fuel is adjusted to zero by completely closing the flow control valve V1 on the second fuel supply line 84, only the first fuel F1 will be supplied to the combustor 4 as fuel F, and the gas turbine 1 will operate exclusively on the first fuel F1 (in this case, the co-firing ratio γ is zero). On the other hand, if the flow control valve V1 is opened and the flow rate of the second fuel is made greater than zero, a mixed fuel of the first fuel F1 and the second fuel F2 will be supplied to the combustor 4 as fuel F, and the gas turbine 1 will operate in a co-firing state (in this case, the co-firing ratio γ will be greater than zero).

[0038] Next, a gas turbine control device 100 for controlling the gas turbine 1 having the above configuration will be described. Figure 5 is an overall schematic diagram of the gas turbine control device 100 according to one embodiment. Each processing function of the gas turbine control device 100 is composed of software (computer program) and executed by a computer, but is not limited to this and may also be composed of hardware.

[0039] At least one operating parameter of the gas turbine 1 is input to the gas turbine control device 100. In the example shown in Figure 5, the operating parameters input to the gas turbine control device 100 include a command value (IGV opening command value) relating to the opening of an inlet guide vane (IGV) (not shown) of the compressor 2, the generator output (gas turbine output) measured by the power system PW of the generator connected to the turbine 6, the intake air temperature and intake air pressure measured by the intake air temperature meter Ta and intake air pressure meter Pa, respectively, installed on the compressor 2, the first fuel flow rate measured by the first flow meter FR1, and the second fuel flow rate measured by the second flow meter FR2.

[0040] The IGV opening command value is a signal command value sent from an IGV control device (not shown) for controlling the inlet guide vanes of the compressor 2. However, if the IGV opening can be measured, it may be the measured value of the IGV opening.

[0041] Figure 6 is a block diagram showing the internal configuration of the gas turbine control device 100 shown in Figure 5. The gas turbine control device 100 comprises an index calculation unit 110, a correction coefficient calculation unit 120, a correction unit 130, and a control unit 140.

[0042] The index calculation unit 110 is configured to calculate the index CLCSO corresponding to the turbine inlet temperature T1T of the gas turbine 1 during dedicated combustion operation of the first fuel F1, based on the operating parameters of the gas turbine 1. The definition of the index CLCSO and the specific calculation logic will be described later with reference to Figure 8, but in this embodiment, the index CLCSO is calculated based on the operating parameters of the generator output (gas turbine output), intake air temperature, IGV opening command value, and intake air pressure.

[0043] The correction coefficient calculation unit 120 is configured to calculate a correction coefficient K for correcting the index CLCSO calculated by the index calculation unit 110. The correction coefficient K is calculated based on the co-firing ratio γ. The co-firing ratio γ used in calculating the correction coefficient K can be calculated based on equation (1) above using the first fuel flow rate and the second fuel flow rate, which are among the operating parameters input to the gas turbine control device 100.

[0044] The correction coefficient calculation unit 120 calculates a correction coefficient K corresponding to the co-firing ratio γ using a function FX that defines the relationship between the co-firing ratio γ and the correction coefficient K. The function FX may be stored in a readable memory, such as a memory (not shown) of the gas turbine control device 100. In this case, the corresponding correction coefficient K is calculated by inputting the co-firing ratio γ calculated using operating parameters into the function FX.

[0045] The function FX for calculating the correction factor K is defined, for example, based on the specific heat ratio of the combustion products produced in combustor 4. When a second fuel F2, which has a higher combustion rate, is co-fired with the first fuel F1, the specific heat ratio of the combustion products changes to be higher than when the first fuel F1 is burned exclusively. This increase in the specific heat ratio of the combustion products increases the generator output (gas turbine output) corresponding to the same turbine inlet temperature T1T. The correction factor K is calculated using the function FX, which is defined to take into account the increase in generator output (gas turbine output) that accompanies this increase in the specific heat ratio of the combustion products during co-fired operation compared to exclusive operation.

[0046] Here, Figure 7 shows an example of the function FX of the correction coefficient calculation unit 120 in Figure 6. In this example, the function FX is defined such that the correction coefficient K decreases monotonically as the co-firing ratio γ increases, and the correction coefficient K takes a value of 1 or less.

[0047] Returning to Figure 6, the correction unit 130 is configured to correct the index CLCSO calculated by the index calculation unit 110 using the correction coefficient K calculated by the correction coefficient calculation unit 120. Specifically, the correction unit 130 calculates a corrected index (hereinafter referred to as "corrected index CLCSO'") by multiplying the index CLCSO by the correction coefficient K. As mentioned above, the correction coefficient K is calculated based on the co-firing ratio γ, so the corrected index CLCSO' obtained using the correction coefficient K is an index CLCSO that takes into account the effect of the change in generator output (gas turbine output) due to the change in the specific heat ratio of the combustion products generated in the combustor 4.

[0048] The control unit 140 is configured to control the gas turbine 1 based on the corrected index CLCSO' calculated by the correction unit 130. The control unit 140 generates control commands for the gas turbine 1 by performing calculation processing using the corrected index CLCSO'. The control commands generated by the control unit 140 are transmitted to each operating terminal of the gas turbine 1, thereby realizing the operation control of the gas turbine 1. An example of the specific control logic of the control unit 140 will be described later with reference to Figure 9.

[0049] Next, with reference to Figure 8, the calculation logic for the index CLCSO in the index calculation unit 110 will be explained. Figure 8 is a block diagram showing the configuration of the calculation logic for the index CLCSO in the index calculation unit 110 shown in Figure 6.

[0050] The index CLCSO is a dimensionless parameter of the turbine inlet temperature T1T, and is positively correlated with (proportional to) the turbine inlet temperature T1T. The index CLCSO is set to 0% when the turbine inlet temperature T1T is at its lower limit and to 100% when the turbine inlet temperature T1T is at its upper limit. For example, when the lower limit of the turbine inlet temperature T1T is 700°C and the upper limit of the turbine inlet temperature T1T is 1500°C, the index CLCSO is expressed by the following equation (2). CLCSO(%) = {(Actual output - 700°C MW) / (1500°C MW)} -700℃MW) × 100 (2)

[0051] The actual output is the measured generator output (gas turbine output). 700℃MW is the generator output (gas turbine output) when the turbine inlet temperature T1T is at its lower limit of 700℃ in the environment in which gas turbine 1 is currently located. 1500℃MW is the generator output (gas turbine output) when the turbine inlet temperature T1T is at its upper limit of 1500℃ in the environment in which gas turbine 1 is currently located.

[0052] Based on the calculation logic of the index CLCSO shown in Figure 8, first, the function generator 111a calculates a value of 1500°CMW (temperature-controlled MW) based on the intake air temperature and the IGV opening command value, which are operating parameters input to the gas turbine control device 100. In other words, a value of 1500°CMW is obtained that takes into account the IGV opening and intake air temperature.

[0053] In the function generator 111b, a value of 700°CMW is calculated based on the intake air temperature and the IGV opening command value, which are operating parameters input to the gas turbine control device 100. In other words, a value of 700°CMW that takes into account the IGV opening and intake air temperature is obtained.

[0054] In the divider 112a, the intake pressure (atmospheric pressure), which is an operating parameter input to the gas turbine control device 100, is divided by the standard atmospheric pressure set by the signal generator 113 to obtain the atmospheric pressure ratio (intake pressure / standard atmospheric pressure). In the multiplier 115a, the value of 1500°CMW obtained by the function generator 111a is multiplied by the atmospheric pressure ratio obtained by the divider 112a to obtain a value of 1500°CMW that also takes the atmospheric pressure ratio into account.

[0055] The 1500°CMW value obtained by the multiplier 115a is output to the subtractor 117a via the learning circuit 116. The learning circuit 116 is used to correct deviations in the 1500°CMW value caused by the degradation of the gas turbine 1's characteristics, etc. The multiplier 115b obtains a 700°CMW value that also takes the atmospheric pressure ratio into account by multiplying the 700°CMW value obtained by the function generator 111b with the atmospheric pressure ratio obtained by the divider 112a.

[0056] In subtractor 117a, the value of 700°CMW obtained by multiplier 115b is subtracted from the value of 1500°CMW corrected by learning circuit 116 (1500°CMW - 700°CMW: see equation (1) above). In subtractor 117b, the value of 700°CMW obtained by multiplier 115b is subtracted from the generator output (actual output), which is an operating parameter input to the gas turbine control device 100 (actual output - 700°CMW: see equation (2) above).

[0057] In the divider 112b, the subtraction result of the subtraction unit 117b is divided by the subtraction result of the subtraction unit 117a (see equation (2) above), and thus the index CLCSO is calculated. To express the index CLCSO as a percentage, simply multiply the output value of the divider 112b by 100.

[0058] In the rate setter 118, in order to prevent the valves and other devices that adjust the fuel flow rate from repeatedly opening and closing due to small fluctuations in the indicator CLCSO caused by small fluctuations in the gas turbine output (generator output), the input value from the divider 112b is not immediately output as the indicator CLCSO, but is limited to a predetermined increase / decrease rate before being output.

[0059] Next, with reference to Figure 9, the logic for calculating control commands by the control unit 140 will be explained. Figure 9 is a block diagram showing the configuration of the control command calculation logic of the control unit 140 in Figure 6.

[0060] The control processing performed by the control unit 140 is not limited as long as control commands are generated for the gas turbine 1 based on the corrected index CLCSO', but as an example, fuel distribution control for each fuel injector of the combustor 4 will be described below. In fuel distribution control, a fuel flow command for the main fuel injector 41 (hereinafter referred to as "main fuel flow command MCSO") and a fuel flow command for the pilot fuel injector 42 (hereinafter referred to as "pilot fuel flow command PLCSO") are generated as control commands for the gas turbine 1.

[0061] The control unit 140 includes a total fuel flow rate command calculation unit 141, a fuel distribution ratio calculation unit 142, a main fuel flow rate command calculation unit 143, and a pilot fuel flow rate command calculation unit 144.

[0062] The total fuel flow command calculation unit 141 is configured to calculate the total fuel flow command CSO, which indicates the total flow rate of fuel F supplied to the combustor 4. The total fuel flow command CSO is calculated based on the operating parameters input to the gas turbine control device 100: intake air temperature, IGV opening command value, and generator output (gas turbine output).

[0063] The fuel distribution ratio calculation unit 142 is configured to calculate the fuel distribution ratio for the main fuel injector 41 (hereinafter referred to as "main fuel distribution ratio Rm") and the fuel distribution ratio for the pilot fuel injector 42 (hereinafter referred to as "pilot fuel distribution ratio Rp") based on the corrected index CLCSO' input from the correction unit 130 (see Figure 6). The main fuel distribution ratio Rm and the pilot fuel distribution ratio Rp are calculated by inputting the corrected index CLCSO' from the correction unit 130 to a function that defines the relationship with the corrected index CLCSO'.

[0064] The main fuel flow command calculation unit 143 is configured to calculate the main fuel flow command MCSO based on the total fuel flow command CSO calculated by the total fuel flow command calculation unit 141 and the main fuel distribution ratio Rm calculated by the fuel distribution ratio calculation unit 142. Specifically, the main fuel flow command MCSO is calculated by multiplying the total fuel flow command CSO by the main fuel distribution ratio Rm.

[0065] The pilot fuel flow rate command calculation unit 144 is configured to calculate the pilot fuel flow rate command PLCSO based on the total fuel flow rate command CSO calculated by the total fuel flow rate command calculation unit 141 and the pilot fuel distribution ratio Rp calculated by the fuel distribution ratio calculation unit 142. Specifically, the pilot fuel flow rate command PLCSO is calculated by multiplying the total fuel flow rate command CSO by the pilot fuel distribution ratio Rp.

[0066] Furthermore, either the main fuel flow command (MCSO) or the pilot fuel flow command (PLCSO) may be calculated by subtracting the other from the total fuel flow command (CSO).

[0067] The control commands generated by the control unit 140 are output to the corresponding operating terminals of the gas turbine 1, thereby performing gas turbine control. Specifically, the flow rate of pilot fuel Fp is adjusted by controlling the opening degree of the flow control valve V3 provided in the branch line 85a based on the pilot fuel flow command PLCSO generated as a control command, and the flow rate of main fuel Fm is adjusted by controlling the opening degree of the flow control valve V4 provided in the branch line 85b based on the main fuel flow command MCSO generated as a control command, thereby achieving a predetermined fuel distribution ratio in the gas turbine 1.

[0068] Next, we will explain the behavior of the gas turbine 1 controlled by the gas turbine control device 100 described above. Here, we will first describe a comparative example of the gas turbine control method implemented by the gas turbine control device 100. Figure 10 is a diagram showing the relationship between the generator output (gas turbine output) and the index CLCSO in the gas turbine 1 controlled by the gas turbine control method according to the comparative example.

[0069] In the comparative example gas turbine control method, the control command is generated by inputting the index CLCSO calculated by the index calculation unit 110 in the aforementioned gas turbine control device 100 directly to the control unit 140 without correcting it using a correction coefficient K (that is, the control unit 140 generates the control command using the index CLCSO itself instead of the corrected index CLCSO').

[0070] As mentioned above with reference to Figure 8, the index CLCSO is calculated based on the generator output (gas turbine output), intake air temperature, IGV opening command value, and intake air temperature. However, for the sake of simplicity, we will assume here that the intake air temperature, IGV opening command value, and intake air temperature are constant, and that the index CLCSO is calculated based only on the generator output (gas turbine output). This index CLCSO is calculated assuming dedicated combustion operation using only the first fuel F1 as fuel F in gas turbine 1, and as shown by the dashed line in Figure 10, it has a monotonically increasing relationship with the generator output (gas turbine output). Therefore, even in the comparative example where gas turbine 1 is controlled based on the index CLCSO, which has not been corrected using the correction coefficient K, appropriate gas turbine control is possible when gas turbine 1 is in dedicated combustion operation.

[0071] On the other hand, during co-firing operation, the second fuel F2, which has a higher burning rate than the first fuel F1, is mixed with the first fuel F1 and burned together. As a result, the amount of water contained in the combustion products increases compared to when the first fuel F1 is burned exclusively, and the specific heat ratio κ of the combustion products (the ratio of rated specific heat capacity to constant-volume specific heat capacity) increases. In other words, the second specific heat ratio κ2 of the combustion products generated during co-firing operation is higher than the first specific heat ratio κ of the combustion products generated during exclusive firing operation, so the generator output (gas turbine output) corresponding to the same turbine inlet temperature T1T increases.

[0072] For these reasons, the characteristics of the generator output (gas turbine output) at turbine inlet temperature T1T change depending on the co-firing ratio γ. In particular, during co-firing operation using a second fuel F2 which has a higher combustion rate than the first fuel F1, the true gas turbine characteristics shift to the higher output side compared to pure combustion operation, as shown by the dashed line in Figure 10. The amount of this shift depends on the co-firing ratio γ.

[0073] In the comparative example, gas turbine control is performed based on the index CLCSO itself without considering that the gas turbine characteristics are affected by the co-firing ratio γ, which may lead to a decrease in control accuracy. For example, as shown in Figure 10, in the comparative example, when the generator output (gas turbine output) of gas turbine 1, which is operating in co-firing mode, is at a value of MW1, the operating state is actually operating point B, but it is mistakenly recognized as operating point A. As a result, in the gas turbine control of the comparative example, a control command is generated based on the index CLCSO corresponding to the mistakenly recognized operating state, and combustion oscillations may occur in gas turbine 1 controlled by this control command.

[0074] Figure 11 shows the relationship between the generator output (gas turbine output) and the corrected index CLCSO' during co-firing operation in a gas turbine controlled by a gas turbine control method according to one embodiment. For reference, Figure 11 also shows the gas turbine characteristics during co-firing operation in a comparative example shown in Figure 10.

[0075] In the gas turbine control device 100 of this embodiment, the control unit 140 does not use the index CLCSO, but rather the index CLCSO is corrected using a correction coefficient K calculated based on the co-firing ratio γ, resulting in a corrected index CLCSO'. As shown in Figure 11, this corrected index CLCSO' substantially matches the true gas turbine characteristics during co-firing operation shown in Figure 10. This means that the corrected index CLCSO' functions well as an index that takes into account the influence of changes in the specific heat ratio of combustion products generated in the combustor 4 during co-firing operation. Therefore, in this embodiment, by generating control commands based on the corrected index CLCSO', the gas turbine 1 can be controlled accurately even during co-firing operation, and combustion vibrations and the like can be effectively prevented.

[0076] This disclosure is not limited to the embodiments described above, but also includes modified forms of the embodiments described above, as well as forms that combine these forms as appropriate.

[0077] The contents described in each of the above embodiments can be understood, for example, as follows:

[0078] (1) A gas turbine control device according to one embodiment is: A gas turbine control device for controlling a gas turbine capable of co-firing a first fuel and a second fuel different from the aforementioned first fuel, An index calculation unit for calculating an index corresponding to the turbine inlet temperature of the gas turbine during dedicated combustion operation of the first fuel, based on at least one operating parameter of the gas turbine, A correction coefficient calculation unit for calculating a correction coefficient based on a co-firing ratio that indicates the proportion of the second fuel to the total fuel supplied to the gas turbine, A correction unit for calculating a corrected index by correcting the aforementioned index using the correction coefficient, A control unit for controlling the gas turbine based on the corrected index, It is equipped with.

[0079] According to the embodiment of (1) above, a corrected index is calculated by correcting the index calculated in accordance with the turbine inlet temperature during the exclusive combustion operation of the first fuel using a correction coefficient. The correction coefficient is calculated based on the co-combustion ratio, which indicates the proportion of the second fuel to the total fuel. By controlling the gas turbine based on the corrected index calculated in this way, it is possible to perform gas turbine control that takes into account the effect on the gas turbine characteristics when the specific heat ratio of the combustion products changes during co-combustion operation of the first and second fuels compared to when the exclusive combustion operation of the first fuel is performed. As a result, the control accuracy during co-combustion operation can be improved, and combustion vibrations and the like can be effectively prevented.

[0080] (2) In other embodiments, in the embodiment of (1) above, The correction coefficient is calculated based on the change in the output characteristics of the gas turbine, which corresponds to the difference between the first specific heat ratio of the combustion products during pure combustion operation of the first fuel and the second specific heat ratio of the combustion products during co-combustion operation of the first and second fuels.

[0081] During co-firing operation, the specific heat ratio of combustion products changes compared to pure-firing operation, which alters the output characteristics of the gas turbine. According to the embodiment of (2) above, the correction coefficient used to correct the index is calculated based on the change in the output characteristics of the gas turbine corresponding to the difference between the first specific heat ratio of combustion products during pure-firing operation and the second specific heat ratio of combustion products during co-firing operation. This allows for correction of the index that takes into account the effect of changes in the specific heat ratio of combustion products.

[0082] (3) In other embodiments, in the embodiment of (2) above, The second fuel has a higher combustion rate than the first fuel. The correction coefficient is calculated based on the increase in the output of the gas turbine due to the increase in the second specific heat ratio relative to the first specific heat ratio.

[0083] According to the embodiment described in (3) above, when a second fuel with a higher combustion rate than the first fuel is co-fired with the first fuel, the correction coefficient used to correct the index is calculated based on the increase in gas turbine output due to the increase in the specific heat ratio of combustion products compared to pure combustion operation. This makes it possible to correct the index to take into account the effect of the higher specific heat ratio of combustion products during co-fired operation.

[0084] (4) In other embodiments, in the embodiment of (3) above, The aforementioned correction factor is 1 or less.

[0085] According to the embodiment described in (4) above, when a second fuel having a higher combustion rate than the first fuel is co-fired with the first fuel, the correction coefficient calculated based on the co-firing ratio will be 1 or less.

[0086] (5) In other embodiments, in any one embodiment of (1) to (4) above, The at least one operating parameter includes at least one of the output of the gas turbine, the IGV opening, the intake air temperature, or the intake air pressure.

[0087] According to the embodiment of (5) above, by using these operating parameters, an index corresponding to the turbine inlet temperature during dedicated combustion operation of the first fuel can be suitably calculated.

[0088] (6) In other embodiments, in any one embodiment of (1) to (5) above, The control unit controls the fuel distribution ratio to the plurality of fuel injectors of the gas turbine based on the corrected index.

[0089] According to the embodiment of (6) above, fuel distribution control for controlling the fuel distribution ratio to the multiple fuel injectors of the gas turbine can be performed with good control accuracy even during co-firing operation.

[0090] (7) In other embodiments, in any one embodiment of (1) to (5) above, The aforementioned index is a dimensionless value obtained by non-dimensionalizing the turbine inlet temperature.

[0091] According to the embodiment of (7) above, by using the above index as a dimensionless value of the turbine inlet temperature, good control accuracy can be obtained without actually measuring the turbine inlet temperature.

[0092] (8) In other embodiments, in the embodiment of (7) above, The aforementioned index is calculated based on the first and second planned outputs of the gas turbine, which correspond to the lower and upper limits of the turbine inlet temperature during dedicated combustion operation of the first fuel, and the actual output of the gas turbine.

[0093] According to the embodiment of (8) above, an index obtained by non-dimensionalizing the turbine inlet temperature can be suitably calculated.

[0094] (9) In other embodiments, in any one embodiment of (1) to (8) above, The first fuel is natural gas, The first fuel is hydrogen.

[0095] According to the embodiment of (9) above, in a gas turbine capable of co-firing hydrogen with natural gas, the occurrence of combustion vibrations and the like can be effectively prevented even during co-firing operation.

[0096] (10) A gas turbine control method according to one embodiment is: A gas turbine control method for controlling a gas turbine capable of co-firing a first fuel and a second fuel different from the first fuel, A step of calculating an index corresponding to the turbine inlet temperature of the gas turbine during dedicated combustion operation of the first fuel, based on at least one operating parameter of the gas turbine; A step of calculating a correction coefficient based on a co-firing ratio that indicates the ratio of the second fuel to the total fuel supplied to the gas turbine, The process of calculating a corrected index by correcting the aforementioned index using the correction coefficient, A step of controlling the gas turbine based on the corrected index, It is equipped with.

[0097] According to the embodiment of (10) above, a corrected index is calculated by correcting the index calculated in accordance with the turbine inlet temperature during the exclusive combustion operation of the first fuel using a correction coefficient. The correction coefficient is calculated based on the co-combustion ratio, which indicates the proportion of the second fuel to the total fuel. By controlling the gas turbine based on the corrected index calculated in this way, it is possible to perform gas turbine control that takes into account the effect on the gas turbine characteristics when the specific heat ratio of the combustion products changes during the co-combustion operation of the first and second fuels compared to the exclusive combustion operation of the first fuel. As a result, the control accuracy during co-combustion operation can be improved, and combustion vibrations and the like can be effectively prevented. [Explanation of symbols]

[0098] 1 Gas Turbine 2 Compressor 4 Combustor 6 Turbines 8 rotors 10 Compressor compartment 12 Air intake 14 Entrance Information Wing 16 Static Wings 18 Moving blade 20 Casing 22 Turbine casing 24 Static Wing 26 Moving blade 28 Exhaust chamber 30 Exhaust chamber 40 Combustion chamber 40a Cabin entrance 41 Main fuel injector 42 Pilot fuel injectors 43 Air passage 45 Outer cylinder 47 Inner cylinder 48 Tailpiece 50 Pilot Combustion Burner 52 Fuel Ports 54 Pilot Nozzle 56 Pilot burner tube 56a Main body 56b Cone section 62 Fuel Ports 58 Swara 64 Main Nozzle 65 Extension tube 66 Main burner tube 70 Swara 80 Fuel supply system 81 1st fuel supply source 82. Fuel supply line 1 83 Secondary fuel source 84. Second fuel supply line 85 Main fuel supply line 85a, 85b branch line 100 Gas Turbine Control System 110 Indicator calculation section 120 Correction coefficient calculation unit 130 Correction section 140 Control Unit 141 Total Fuel Flow Rate Command Calculation Unit 142 Fuel distribution ratio calculation section 143 Main fuel flow rate command calculation unit 144 Pilot fuel flow rate command calculation unit CLCSO indicator CLCSO´ corrected index CSO Total Fuel Flow Command MCSO Main Fuel Flow Command PLCSO Pilot Fuel Flow Command F fuel F1 1st fuel F2 2nd fuel Fm Main Fuel Fp Pilot Fuel K correction factor

Claims

1. A gas turbine control device for controlling a gas turbine capable of co-firing a first fuel and a second fuel different from the aforementioned first fuel, An index calculation unit for calculating an index corresponding to the turbine inlet temperature of the gas turbine during dedicated combustion operation of the first fuel, based on at least one operating parameter of the gas turbine, A correction coefficient calculation unit for calculating a correction coefficient based on a co-firing ratio that indicates the ratio of the second fuel to the total fuel supplied to the gas turbine, A correction unit for calculating a corrected index by correcting the aforementioned index using the correction coefficient, A control unit for controlling the gas turbine based on the corrected index, A gas turbine control device equipped with the following features.

2. The gas turbine control device according to claim 1, wherein the correction coefficient is calculated based on the amount of change in the output characteristics of the gas turbine corresponding to the difference between the first specific heat ratio of the combustion products during operation using only the first fuel and the second specific heat ratio of the combustion products during operation using a mixture of the first fuel and the second fuel.

3. The second fuel has a higher combustion rate than the first fuel. The gas turbine control device according to claim 2, wherein the correction coefficient is calculated based on the increase in the output of the gas turbine due to the increase in the second specific heat ratio relative to the first specific heat ratio.

4. The gas turbine control device according to claim 3, wherein the correction coefficient is 1 or less.

5. The gas turbine control device according to claim 1 or 2, wherein the at least one operating parameter includes at least one of the output of the gas turbine, the IGV opening, the intake air temperature, or the intake air pressure.

6. The gas turbine control device according to claim 1 or 2, wherein the control unit controls the fuel distribution ratio to a plurality of fuel injectors of the gas turbine based on the corrected index.

7. The gas turbine control device according to claim 1 or 2, wherein the index is a dimensionless value obtained by non-dimensionalizing the turbine inlet temperature.

8. The gas turbine control device according to claim 7, wherein the indicator is calculated based on the first planned output and second planned output of the gas turbine, which correspond to the lower limit and upper limit of the turbine inlet temperature during dedicated combustion operation of the first fuel, respectively, and the actual output of the gas turbine.

9. The first fuel is natural gas, The gas turbine control device according to claim 1 or 2, wherein the second fuel is hydrogen.

10. A gas turbine control method for controlling a gas turbine capable of co-firing a first fuel and a second fuel different from the first fuel, A step of calculating an index corresponding to the turbine inlet temperature of the gas turbine during dedicated combustion operation of the first fuel, based on at least one operating parameter of the gas turbine; A step of calculating a correction coefficient based on a co-firing ratio that indicates the ratio of the second fuel to the total fuel supplied to the gas turbine, The process of calculating a corrected index by correcting the aforementioned index using the correction coefficient, A step of controlling the gas turbine based on the corrected index, A gas turbine control method comprising:

Images