Gas turbine control device, gas turbine control method, and gas turbine control program

Abstract

According to at least one embodiment of the present disclosure, in a gas turbine capable of co-firing different fuels, misfires are prevented when a fuel with a lower heat output per unit volume is shut off. [Solution] This disclosure relates to a gas turbine control device for controlling a gas turbine equipped with a combustor capable of co-firing a first fuel and a second fuel having a lower heat content per unit volume. The gas turbine control device includes a supply state determination unit for determining the supply state of the second fuel to the combustor, and a pilot fuel ratio control unit for controlling the pilot fuel ratio, which is the fuel distribution ratio to a pilot fuel injection nozzle among a plurality of fuel injection nozzles of the combustor. If the pilot fuel ratio control unit determines that the supply state is in a shut-off state, it controls the pilot fuel ratio to temporarily increase.

Description

Technical Field

[0004] , , , , , ,

[0003] , , , ,

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

Background Art

[0002] Gas turbines that can be driven using combustion gas generated by the combustion of fuel are known. Gas turbines are used, for example, in gas turbine power generation facilities that generate electricity by connecting a generator to their output shafts. The fuel used in gas turbines includes, for example, liquefied natural gas (LNG: Liquefied Natural Gas) that is mined as raw natural gas from gas fields and liquefied and refined. In recent years, the development of gas turbines capable of co-firing fuels such as hydrogen (second fuel) with relatively low heat per unit volume with fuels such as such liquefied natural gas (first fuel) has been underway (see, for example, Patent Document 1). In the co-firing operation of such gas turbines, the flow rate of each fuel is controlled so that the co-firing rate reaches a predetermined value.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a gas turbine capable of co-firing operation as described above, when the second fuel is shut off due to some factor, the operation may be continued by switching from co-firing operation to dedicated firing operation using the first fuel. At this time, if the opening degree of the flow rate adjustment valve installed in the fuel supply line is maintained constant, the volume density of the fuel supplied to the combustor decreases while the differential pressure before and after the flow rate adjustment valve remains constant, and the turbine inlet temperature temporarily decreases, which may cause misfire in the gas turbine.

[0005] 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, a gas turbine control method, and a gas turbine control program that can prevent misfires from occurring when a fuel with a low heat content per unit volume is shut off in a gas turbine capable of co-firing different fuels. [Means for solving the problem]

[0006] 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 equipped with a combustor capable of co-firing a first fuel and a second fuel having a lower heat content per unit volume than the first fuel, A supply state determination unit for determining the supply state of the second fuel to the combustor, A pilot fuel ratio control unit for controlling the pilot fuel ratio, which is the fuel distribution ratio to a pilot fuel injection nozzle among a plurality of fuel injection nozzles having the combustor, Equipped with, The pilot fuel ratio control unit controls the pilot fuel ratio to temporarily increase it when the supply state determination unit determines that the supply state is shut off.

[0007] 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 equipped with a combustor capable of co-firing a first fuel and a second fuel having a lower heat content per unit volume than the first fuel, A step of determining the supply state of the second fuel to the combustor, A step of controlling the pilot fuel ratio, which is the fuel distribution ratio to the pilot fuel injection nozzle among the plurality of fuel injection nozzles of the combustor, Equipped with, The pilot fuel ratio is controlled to temporarily increase if it is determined that the supply state is interrupted.

[0008] A gas turbine control program according to at least one embodiment of this disclosure solves the above problems. A gas turbine control program for controlling a gas turbine equipped with a combustor capable of co-firing a first fuel and a second fuel having a lower heat content per unit volume than the first fuel, Using a computer device, A step of determining the supply state of the second fuel to the combustor, A step of controlling the pilot fuel ratio, which is the fuel distribution ratio to the pilot fuel injection nozzle among the plurality of fuel injection nozzles of the combustor, It is possible to do this, The pilot fuel ratio is controlled to temporarily increase if it is determined that the supply state is interrupted. [Effects of the Invention]

[0009] According to at least one embodiment of the present disclosure, a gas turbine control device, a gas turbine control method, and a gas turbine control program can be provided that can prevent misfires from occurring when a fuel with a low heat output per unit volume is shut off in a gas turbine capable of co-firing different fuels. [Brief explanation of the drawing]

[0010] [Figure 1] This figure shows a schematic configuration of a gas turbine according to one embodiment. [Figure 2] Figure 1 is a schematic diagram showing an example of a specific configuration of the main fuel supply path from the main fuel supply line to some of the fuel injection nozzles in the combustor of the gas turbine. [Figure 3] This is a block diagram showing the functional configuration of a gas turbine control device according to one embodiment. [Figure 4] This graph shows the time course of the turbine inlet temperature in a comparative example of a gas turbine control method when the second fuel is shut off during co-firing operation of a gas turbine. [Figure 5]A timing chart showing the time evolution of each operating parameter in a gas turbine controlled by the gas turbine control device of FIG. 3, together with a comparative example. [Figure 6] A graph showing the time evolution of the turbine inlet temperature corresponding to the present embodiment of FIG. 5.

Embodiments of the Invention

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

[0012] First, referring to FIG. 1, the gas turbine 1 that 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 diagram showing a schematic configuration of the gas turbine 1 according to one embodiment.

[0013] The gas turbine 1 includes a compressor 3 for generating compressed air, a combustor 2 for generating combustion gas by mixing and burning the compressed air generated by the compressor 3 with fuel, a fuel supply system 4 for supplying fuel to the combustor 2, and a turbine 6 that can be driven by the combustion gas as a working fluid. The compressor 3 and the turbine 6 are connected on a single shaft. In the gas turbine 1 having such a configuration, the combustor 2 is supplied with compressed air compressed by the compressor 3 and fuel supplied from the fuel supply system 4, and these are mixed and burned to generate combustion gas. This combustion gas flows into the turbine 6 and functions as power for driving the turbine 6.

[0014] The fuel supply system 4 is configured to supply fuel to the combustor 2. The fuel supply system 4 of the present embodiment supplies at least one of the first fuel F1 or the second fuel F2 as fuel, and constitutes a gas turbine 1 capable of co-firing the first fuel F1 and the second fuel F2. The second fuel F2 is a fuel having a lower calorific value per unit volume than the first fuel F1. In the present embodiment, the first fuel F1 is liquefied natural gas (LNG: Liquefied Natural Gas), and the second fuel F2 is hydrogen gas.

[0015] The fuel supply system 4 has a first fuel supply line 8 for supplying the first fuel F1 from the first fuel supply section 7 and a second fuel supply line 16 for supplying the second fuel F2 from the second fuel supply section 14. A flow meter 10 for detecting the flow rate of the first fuel F1 is provided in the first fuel supply line 8, and a flow rate adjusting valve 18 for adjusting the flow rate of the second fuel F2, a flow meter 15 for detecting the flow rate of the second fuel F2, a shut-off valve 13 for shutting off the second fuel F2, and a pressure sensor 19 for detecting the supply pressure of the second fuel F2 are provided in the second fuel supply line 16.

[0016] The first fuel supply line 8 and the second fuel supply line 16 merge with each other at a merging point 25 on the downstream side. At least one of the first fuel F1 supplied through the first fuel supply line 8 or the second fuel F2 supplied through the second fuel supply line 16 merges at the merging point 25 and is supplied to the combustor 2 as the main fuel Fn through the main fuel supply line 22. In addition, a shut-off valve 24 for shutting off the main fuel Fn and a flow rate adjusting valve 26 for adjusting the flow rate of the main fuel Fn are provided in the main fuel supply line 22.

[0017] The downstream side of the main fuel supply line 22 branches into a plurality of branch pipes 28, and each branch pipe 28 is connected to a plurality of fuel injection nozzles 50 (see Figure 2) of the combustor 2 through a manifold section 29. A flow rate adjusting valve 30 is provided in each of the plurality of branch pipes 28. By adjusting the opening degree of these flow rate adjusting valves 30, the distribution ratio of the main fuel Fn to each branch pipe 28 can be controlled.

[0018] Furthermore, each branch pipe 28 has a manifold section 29 equipped with a pressure sensor 31 for detecting pressure (Figure 1 shows a typical pressure sensor 31 provided on one manifold section 29). In addition, a leak sensor 32 for detecting leakage of the second fuel F2 is provided around the gas turbine 1 (especially in areas where the second fuel F2 may leak, such as the second fuel supply line 16, the main fuel supply line 22, or the branch pipes 28).

[0019] Figure 2 is a schematic diagram showing an example of a specific configuration of the supply path of main fuel Fn from the main fuel supply line 22 to some of the fuel injection nozzles 50 of the combustor 2 in the gas turbine 1 of Figure 1. The combustor 2 has multiple fuel injection nozzles 50, including pilot fuel injection nozzles 50p and main fuel injection nozzles 50m. The pilot fuel injection nozzle 50p is located in the center corresponding to the central axis L of the cylindrical body 52 of the combustor 2, and multiple main fuel injection nozzles 50m are arranged circumferentially around the pilot fuel injection nozzle 50p. The pilot fuel injection nozzle 50p uses pilot fuel Fp, which is the main fuel Fn supplied from the main fuel supply line 22 via the branch pipe 28p, to form a flame in the downstream combustion chamber 54. The main fuel injection nozzle 50m uses main fuel Fm, which is the main fuel Fn supplied from the main fuel supply line 22 via the branch pipe 28m, to form a flame in the downstream combustion chamber 54.

[0020] In Figure 2, the flow control valves 30 provided in the branch pipe 28 of Figure 1 are shown as a flow control valve 30p for adjusting the flow rate of pilot fuel Fp supplied to the pilot fuel injection nozzle 50p, and a flow control valve 30m for adjusting the flow rate of main fuel Fm supplied to the main fuel injection nozzle 50m.

[0021] Next, a gas turbine control device 100 for controlling the gas turbine 1 having the above configuration will be described. The gas turbine control device 100 is a control unit for controlling the gas turbine 1 and consists of, for example, a CPU (Central Processing Unit), RAM (Random Access Memory), ROM (Read Only Memory), and a computer-readable storage medium. A series of processes for realizing various functions are stored in the storage medium in the form of a program, for example, and the CPU reads this program into the RAM and executes information processing and calculations to realize various functions. The program may be pre-installed in ROM or other storage media, provided in a state where it is stored in a computer-readable storage medium, or distributed via wired or wireless communication means. Computer-readable storage media include magnetic disks, magneto-optical disks, CD-ROMs, DVD-ROMs, semiconductor memory, etc.

[0022] Figure 3 is a block diagram showing the functional configuration of a gas turbine control device 100 according to one embodiment. The gas turbine control device 100 includes a supply state determination unit 102, an operation parameter acquisition unit 104, and a control unit 106.

[0023] The supply status determination unit 102 is configured to determine the supply status of the second fuel F2 to the combustor 2. In this embodiment, the gas turbine 1 is configured to determine whether or not the second fuel F2 has been shut off in a mixed-fire operation state in which both the first fuel F1 and the second fuel F2 are supplied from the fuel supply system 4 (in other words, an operation state in which the main fuel Fn contains a considerable amount of the second fuel F2).

[0024] For example, the shutoff of the second fuel F2 is performed when the fuel mixture ratio, calculated based on the flow rate of the first fuel F1 detected by the flow meter 10 and the flow rate of the second fuel F2 detected by the flow meter 15, exceeds a predetermined reference value. Therefore, the supply state determination unit 102 may determine that the second fuel F2 has been shut off when the fuel mixture ratio exceeds a predetermined reference value.

[0025] Furthermore, the shutoff of the second fuel F2 is performed when the pressure in the second fuel supply line 16, as detected by the pressure sensor 19, falls below a predetermined reference value. Therefore, the supply status determination unit 102 may determine that the second fuel F2 has been shut off when the value detected by the pressure sensor 19 falls below a predetermined reference value.

[0026] Furthermore, the shutoff of the second fuel F2 is performed when the amount of leakage of the second fuel F2 detected by the leak sensor 32 exceeds a predetermined standard value. Therefore, the supply status determination unit 102 may determine that the second fuel F2 has been shut off when the value detected by the leak sensor 32 exceeds a predetermined standard value.

[0027] Furthermore, if any abnormality occurs in any component of the gas turbine 1, and a control signal is sent to the shut-off valve 13 provided in the second fuel supply line 16 in order to shut off the second fuel F2, the supply status determination unit 102 may determine whether or not the second fuel F2 has been shut off based on the control signal.

[0028] The operation parameter acquisition unit 104 is configured to acquire operation parameters indicating the operating state of the gas turbine 1. The operation parameters are arbitrary parameters indicating the operating state of the gas turbine 1 and may include values ​​detected by sensors, control parameters, and calculation results using these.

[0029] The control unit 106 is configured to control the gas turbine 1 based on the operating parameters acquired by the operating parameter acquisition unit 104. The control parameters handled by the control unit 106 can be arbitrarily selected, but Figure 3 shows some of the components of the control unit 106, including a pilot fuel ratio control unit 108 that handles the pilot fuel ratio Rp as a control parameter, a fuel flow rate control unit 110 that handles the fuel flow rate as a control parameter, and an output control unit 112 that handles the output of the gas turbine 1 as a control parameter.

[0030] The pilot fuel ratio control unit 108 is configured to control the pilot fuel ratio Rp based on operating parameters. The pilot fuel ratio Rp is defined as the ratio of the flow rate of pilot fuel Fp to the total flow rate of main fuel Fn supplied to the combustor 2. The control of the pilot fuel ratio Rp by the pilot fuel ratio control unit 108 uses PID control, for example, so that the measured value of the pilot fuel ratio Rp (calculation result using the detected values ​​of flow meters 10 and 15) becomes the target value of the pilot fuel ratio, which corresponds to the pilot fuel ratio Rp.

[0031] The fuel flow control unit 110 is configured to control the flow rate of the first fuel F1 when the second fuel F2 is shut off, based on operating parameters. The flow rate control by the fuel flow control unit 110 uses PID control so that the measured value of the first fuel F1 (the value detected by the flow meter 10) becomes a target flow rate value, which corresponds to the flow rate of the first fuel F1.

[0032] The output control unit 112 is configured to control the output of the gas turbine 1 based on operating parameters. The output control of the gas turbine 1 by the output control unit 112 uses PID control so that the measured value of the output of the gas turbine 1 becomes the target output value, which corresponds to the output of the gas turbine 1.

[0033] Next, in the gas turbine control device 100 having the above configuration, if a malfunction occurs while the gas turbine 1 is operating in a mixed-fire state by supplying both the first fuel F1 and the second fuel F2 from the fuel supply system 4, the second fuel F2 may be shut off by closing the shut-off valve 13 provided in the second fuel supply line 16 (the specific circumstances under which the second fuel F2 is shut off are as described above). As a result, the gas turbine 1 can continue operating even when a malfunction occurs by switching from mixed-fire operation using the first fuel F1 and the second fuel F2 to dedicated-fire operation using only the first fuel F1.

[0034] Here, Figure 4 is a graph showing the temporal change of the turbine inlet temperature T1T in a comparative example of a gas turbine control method when the second fuel F2 is shut off in the gas turbine 1 during co-firing operation. In the comparative example, as will be described later with reference to Figure 5, after the second fuel F2 is shut off at time ta, the output setpoint of the gas turbine 1, the pilot fuel ratio Rp, and the opening degree of the flow control valve installed in the supply channel of the main fuel Fn are maintained at a constant level. In such a comparative example, when the second fuel F2 is shut off at time ta, as shown in Figure 4, the turbine inlet temperature T1T does not change significantly for a while due to the remaining second fuel F2, but eventually the turbine inlet temperature T1T begins to decrease, and shows a temporary downward behavior, reaching its lowest value at time tc when the main fuel Fn (i.e., fuel with 100% first fuel F1) reaches the fuel injection nozzle after the second fuel F2 has been shut off. This indicates that, in order to maintain a stable operating state of gas turbine 1, if the opening of the flow control valve installed in the supply channel of the main fuel Fn is kept constant, the volume density of the fuel supplied to combustor 2 decreases while the differential pressure across the flow control valve remains constant, causing a temporary decrease in the turbine inlet temperature T1T. Such a temporary decrease in turbine inlet temperature T1T can lead to misfires in gas turbine 1. Subsequently, from time td onward, the turbine inlet temperature T1T, which had temporarily decreased, shows behavior of overshooting significantly towards the high-temperature side.

[0035] In this comparative example, if the second fuel F2 is shut off in the gas turbine 1 operating in co-firing mode, the turbine inlet temperature T1T may fluctuate, potentially leading to misfire or overshoot. This problem in the comparative example can be suitably solved by the gas turbine control method implemented by the gas turbine control device 100 described below.

[0036] Next, the gas turbine control method implemented by the gas turbine control device 100 having the above configuration will be described in detail, in comparison with the comparative example described above. Figure 5 is a timing chart showing the temporal progression of each operating parameter in the gas turbine 1 controlled by the gas turbine control device 100 of Figure 3, together with the comparative example of Figure 4.

[0037] The timing charts in Figure 5 show control examples, along with comparative examples, for a gas turbine 1 in which co-firing operation is performed by supplying first fuel F1 and second fuel F2 to the combustor 2 by the fuel supply system 4, when the second fuel F2 is shut off at time ta due to some factor. At time ta, the shut-off valve 13 provided in the second fuel supply line 16 is switched from the open state to the closed state, thereby shutting off the second fuel F2. Consequently, at time ta, the mixing ratio of the second fuel F2 in the main fuel Fn decreases to 0%. The main fuel Fn after the shut-off of the second fuel F2 (i.e., fuel with 100% first fuel F1) reaches the fuel injection nozzle at time tc. Figure 5 shows how various operating parameters, such as the turbine inlet temperature T1T, change after time ta when the second fuel Fa is shut off.

[0038] In the comparative example, around the time ta when the second fuel F2 is shut off, the output setpoint of the gas turbine 1, the pilot fuel ratio Rp, and the opening degree of the flow control valve installed in the supply channel of the main fuel Fn are kept constant. As mentioned above with reference to Figure 4, with a constant differential pressure across the flow control valve, the volume density of the fuel supplied to the combustor 2 decreases, and the turbine inlet temperature T1T temporarily drops around time tc, making the gas turbine 1 more prone to misfires. Furthermore, after time td, the turbine inlet temperature T1T overshoots significantly towards the high temperature side.

[0039] In contrast to the comparative example, in this embodiment, when the supply state determination unit 102 determines that the second fuel F2 has been shut off at time ta, the pilot fuel ratio control unit 108 of the control unit 106 controls the pilot fuel ratio Rp to be temporarily increased compared to the comparative example from time ta, which is the first time point, until time tc, when the period T has elapsed. As described above with reference to Figure 4, in the comparative example, when the second fuel F2 is shut off, the turbine inlet temperature T1T temporarily decreases, making it more likely that a misfire will occur. In contrast, in this embodiment, during the period when the turbine inlet temperature T1T is likely to decrease, the fuel injection ratio by the pilot fuel injection nozzle 50p is temporarily increased to improve combustion stability and effectively prevent a misfire from occurring in the gas turbine 1.

[0040] In this embodiment, the fuel flow control unit 110 of the control unit 106 maintains the flow rate of the first fuel F1 at approximately a constant level from the first time point ta to the second time point td, which is a predetermined time after that time, and controls the flow rate of the first fuel F1 to decrease thereafter. More specifically, in this embodiment, the gas turbine output setpoint is reduced at time tb, but the decrease in the opening degree of the flow control valve is suppressed until time td. For example, the flow rate of the first fuel F1 is maintained by keeping the opening degree of the flow control valve within a predetermined range or constant. As a result, by maintaining the flow rate of the first fuel F1 between time ta and time td, the decrease in the turbine inlet temperature T1T is suppressed, and the risk of misfire is suitably reduced. On the other hand, by reducing the flow rate of the first fuel F1 thereafter, it is possible to suppress the overshoot of the turbine inlet temperature T1T towards the high-temperature side.

[0041] In this embodiment, the second time point (time td) is described as the time after a predetermined period has elapsed from the first time point (time ta). However, it is also possible to set the second time point as the time after a predetermined period has elapsed from the time when a pressure drop is detected by the pressure sensor 31 provided in the manifold section 29. Even when the second time point is set in this way, the overshoot of the turbine inlet temperature T1T can be suitably suppressed by reducing the flow rate of the first fuel F1 in accordance with the timing when an overshoot to the high-temperature side occurs in the turbine inlet temperature T1T.

[0042] Furthermore, in this embodiment, the output control unit 112 of the control unit 106 controls the output setting value of the gas turbine 1 to decrease compared to the comparative example from time tb, which is the third time point. By reducing the output setting value of the gas turbine 1 in this way, the output of the gas turbine 1 is reduced, and the overshoot that occurs when the second fuel F2 is shut off can be effectively suppressed.

[0043] Furthermore, the third time point (time tb) at which this control of reducing the output setpoint of the gas turbine 1 is implemented can be set as the time after a predetermined period has elapsed from the time when a pressure drop is detected by the pressure sensor 31 provided in the manifold section 29. By setting the third time point in this way, the output of the gas turbine 1 can be reduced in accordance with the timing at which an overshoot occurs in the turbine inlet temperature T1T in Figure 4, thereby effectively suppressing the overshoot of the turbine inlet temperature T1T.

[0044] Figure 6 is a graph showing the temporal progression of the turbine inlet temperature T1T corresponding to this embodiment in Figure 5. In this embodiment, the temporary drop in the turbine inlet temperature T1T that occurs when the second fuel F2 is shut off in Figure 4 is suppressed, and misfires of the gas turbine 1 can be effectively prevented. Furthermore, it is shown that the overshoot of the turbine inlet temperature T1T to the high temperature side after the temporary drop in Figure 4 can also be effectively suppressed in this embodiment.

[0045] Furthermore, it is possible to replace the components in the above-described embodiments with well-known components as appropriate, without departing from the spirit of this disclosure, and the above-described embodiments may also be combined as appropriate.

[0046] The contents described in each of the above embodiments can be understood, for example, as follows:

[0047] (1) A gas turbine control device according to one embodiment is: A gas turbine control device for controlling a gas turbine equipped with a combustor capable of co-firing a first fuel and a second fuel having a lower heat content per unit volume than the first fuel, A supply state determination unit for determining the supply state of the second fuel to the combustor, A pilot fuel ratio control unit for controlling the pilot fuel ratio, which is the fuel distribution ratio to a pilot fuel injection nozzle among a plurality of fuel injection nozzles having the combustor, Equipped with, The pilot fuel ratio control unit controls the pilot fuel ratio to temporarily increase it when the supply state determination unit determines that the supply state is shut off.

[0048] According to the embodiment of (1) above, in a gas turbine in which the first fuel and the second fuel are co-fired, when the second fuel is shut off, the pilot fuel ratio, which is the fuel distribution ratio to the pilot fuel injection nozzle among the multiple fuel injection nozzles provided in the combustor, is controlled to temporarily increase. As a result, when the turbine inlet temperature drops due to the decrease in the volumetric flow rate of fuel supplied when the second fuel is shut off, the combustion stability can be improved by increasing the fuel injection ratio by the pilot fuel injection nozzle, and misfires can be effectively prevented.

[0049] (2) In other embodiments, in the embodiment of (1) above, The system further comprises a fuel flow control unit for controlling the flow rate of fuel supplied to the combustor, The fuel flow control unit controls the fuel flow rate to decrease at a second time point later than the first time point at which the pilot fuel ratio is temporarily increased by the pilot fuel ratio control unit.

[0050] According to the embodiment of (2) above, at a second time point later than the first time point in which the pilot fuel ratio is controlled to temporarily increase when the second fuel is shut off, the flow rate of fuel supplied to the combustor is controlled to decrease. As mentioned above, the turbine inlet temperature temporarily decreases when the second fuel is shut off, but then exhibits behavior of overshooting to the high temperature side. In this embodiment, when the turbine inlet temperature overshoots to the high temperature side in this way, the overshoot of the turbine inlet temperature can be suitably suppressed by reducing the flow rate of fuel supplied to the combustor.

[0051] (3) In other embodiments, in the embodiment of (2) above, The fuel flow control unit maintains the fuel flow rate constant until the second time point.

[0052] According to the embodiment of (3) above, the fuel flow rate supplied to the combustor is kept constant until the aforementioned fuel flow rate reduction control is initiated at the second time point. This maintains the fuel flow rate immediately after the shutoff of the second fuel, thereby suppressing a decrease in turbine inlet temperature and effectively reducing the risk of misfire.

[0053] (4) In other embodiments, in the embodiment of (2) or (3) above, The second time point is set as the time after a predetermined period has elapsed since the second fuel was shut off.

[0054] According to the embodiment of (4) above, the second time point at which the temporary reduction control of the fuel flow rate to the combustor is implemented is set to a predetermined period of time that has elapsed since the second fuel was shut off. This allows for the effective suppression of the overshoot by temporarily reducing the fuel flow rate to the combustor at the timing when an overshoot to the high temperature side occurs in the turbine inlet temperature when the second fuel is shut off.

[0055] (5) In other embodiments, in any one embodiment of (1) to (4) above, The gas turbine further comprises an output control unit for controlling the output of the gas turbine, The output control unit controls the output to temporarily decrease it at a third time point, which is later than the first time point at which the pilot fuel ratio is temporarily increased by the pilot fuel ratio control unit.

[0056] According to the embodiment of (5) above, the output of the gas turbine is set to temporarily decrease at a third time point, which is later than the first time point, when the pilot fuel ratio is controlled to temporarily increase when the second fuel is shut off. As mentioned above, the turbine inlet temperature temporarily decreases when the second fuel is shut off, but then exhibits behavior of overshooting to the high temperature side. In this embodiment, when the turbine inlet temperature overshoots to the high temperature side in this way, the overshoot of the turbine inlet temperature can be suitably suppressed by temporarily reducing the output of the gas turbine.

[0057] (6) In other embodiments, in the embodiment of (5) above, The third time point is set as the time after a predetermined period has elapsed since the time when a pressure drop was detected by a pressure sensor provided in the manifold section connected to the plurality of fuel injection nozzles.

[0058] According to the embodiment of (6) above, the third time point at which the output of the gas turbine is controlled to temporarily decrease is set as a predetermined period elapsed from the time when a pressure drop is detected by a pressure sensor provided in the manifold. This allows for the effective suppression of the overshoot by temporarily reducing the output of the gas turbine at the timing when an overshoot to the high temperature side occurs in the turbine inlet temperature when the second fuel is shut off.

[0059] (7) In other embodiments, in any one embodiment of (1) to (6) above, The supply status determination unit determines the supply status based on the detection result of a sensor installed in the fuel supply system for supplying the second fuel to the combustor.

[0060] According to the embodiment of (7) above, the shutoff of the second fuel can be suitably determined based on the detection results of sensors arranged in the fuel supply system.

[0061] (8) In other embodiments, in any one embodiment of (1) to (7) above, The first fuel gas is LNG, The second fuel gas is hydrogen gas.

[0062] According to the embodiment of (8) above, in a gas turbine capable of co-firing LNG and hydrogen gas, misfires can be effectively prevented when the hydrogen gas is shut off due to some factor.

[0063] (9) A gas turbine control method according to one embodiment is: A gas turbine control method for controlling a gas turbine equipped with a combustor capable of co-firing a first fuel and a second fuel having a lower heat content per unit volume than the first fuel, A step of determining the supply state of the second fuel to the combustor, A step of controlling the pilot fuel ratio, which is the fuel distribution ratio to the pilot fuel injection nozzle among the plurality of fuel injection nozzles of the combustor, Equipped with, The pilot fuel ratio is controlled to temporarily increase if it is determined that the supply state is interrupted.

[0064] According to the embodiment of (9) above, in a gas turbine in which the first fuel and the second fuel are co-fired, when the second fuel is shut off, the pilot fuel ratio, which is the fuel distribution ratio to the pilot fuel injection nozzle among the multiple fuel injection nozzles provided in the combustor, is controlled to temporarily increase. As a result, when the turbine inlet temperature drops due to a decrease in the volumetric flow rate of fuel supplied when the second fuel is shut off, the combustion stability can be improved by increasing the fuel injection ratio by the pilot fuel injection nozzle, thereby effectively preventing misfires.

[0065] (10) A gas turbine control program according to one embodiment is: A gas turbine control program for controlling a gas turbine equipped with a combustor capable of co-firing a first fuel and a second fuel having a lower heat content per unit volume than the first fuel, Using a computer device, A step of determining the supply state of the second fuel to the combustor, A step of controlling the pilot fuel ratio, which is the fuel distribution ratio to the pilot fuel injection nozzle among the plurality of fuel injection nozzles of the combustor, It is possible to do this, The pilot fuel ratio is controlled to temporarily increase if it is determined that the supply state is interrupted.

[0066] According to the embodiment of (10) above, in a gas turbine in which the first fuel and the second fuel are co-fired, when the second fuel is shut off, the pilot fuel ratio, which is the fuel distribution ratio to the pilot fuel injection nozzle among the multiple fuel injection nozzles provided in the combustor, is controlled to temporarily increase. As a result, when the turbine inlet temperature drops due to a decrease in the volumetric flow rate of fuel supplied when the second fuel is shut off, the combustion stability can be improved by increasing the fuel injection ratio by the pilot fuel injection nozzle, thereby effectively preventing misfires. [Explanation of Symbols]

[0067] 1 Gas Turbine 2 Combustor 3. Compressor 4 Fuel supply system 6 Turbines 7 1st fuel supply section 8. Fuel supply line 1 10 Flow meter 13 Shut-off valve 14 2nd fuel supply section 15 Flow meter 16. Second fuel supply line 18 Flow control valve 19. Pressure sensor 22 Main fuel supply line 24 Shut-off valve 25 Confluence 26 Flow control valve 28 Branch pipe 29 Manifold section 30 Flow control valve 31 Pressure Sensor 32 Leak Sensors 50 Fuel Injection Nozzles 50m Main Fuel Injection Nozzle 50p Pilot Fuel Injector Nozzle 52 Cylinder 54 Combustion chamber 100 Gas Turbine Control System 102 Supply status determination unit 104 Operation parameter acquisition unit 106 Control Unit 108 Pilot Fuel Ratio Control Unit 110 Fuel flow control unit 112 Output Control Unit F1 1st fuel F2 2nd fuel Fn main fuel Fm Main Fuel Fp Pilot Fuel T1T Turbine Inlet Temperature

Claims

1. A gas turbine control device for controlling a gas turbine equipped with a combustor capable of co-firing a first fuel and a second fuel having a lower heat content per unit volume than the first fuel, A supply state determination unit for determining the supply state of the second fuel to the combustor, A pilot fuel ratio control unit for controlling the pilot fuel ratio, which is the fuel distribution ratio to a pilot fuel injection nozzle among a plurality of fuel injection nozzles having the combustor, Equipped with, The pilot fuel ratio control unit controls the pilot fuel ratio to temporarily increase when the supply state determination unit determines that the supply state is shut off.

2. The system further comprises a fuel flow control unit for controlling the flow rate of fuel supplied to the combustor, The gas turbine control device according to claim 1, wherein the fuel flow control unit controls the flow rate of the fuel at a second time point later than the first time point at which the pilot fuel ratio is temporarily increased by the pilot fuel ratio control unit.

3. The gas turbine control device according to claim 2, wherein the fuel flow control unit maintains the flow rate of the fuel at a constant level until the second time point.

4. The gas turbine control device according to claim 2, wherein the second time point is set as a predetermined period of time elapsed from the time the second fuel is shut off.

5. The gas turbine further comprises an output control unit for controlling the output of the gas turbine, The gas turbine control device according to claim 1 or 2, wherein the output control unit controls the output to temporarily decrease it at a third time point later than the first time point at which the pilot fuel ratio is temporarily increased by the pilot fuel ratio control unit.

6. The gas turbine control device according to claim 5, wherein the third time point is set as a predetermined period of time elapsed from the time when a pressure drop is detected by a pressure sensor provided in the manifold section connected to the plurality of fuel injection nozzles.

7. The gas turbine control device according to claim 1 or 2, wherein the supply status determination unit determines the supply status based on the detection result of a sensor installed in the fuel supply system for supplying the second fuel to the combustor.

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

9. A gas turbine control method for controlling a gas turbine equipped with a combustor capable of co-firing a first fuel and a second fuel having a lower heat content per unit volume than the first fuel, A step of determining the supply state of the second fuel to the combustor, A step of controlling the pilot fuel ratio, which is the fuel distribution ratio to the pilot fuel injection nozzle among the plurality of fuel injection nozzles of the combustor, Equipped with, A gas turbine control method in which the pilot fuel ratio is controlled to temporarily increase when it is determined that the supply state is in a shut-off state.

10. A gas turbine control program for controlling a gas turbine equipped with a combustor capable of co-firing a first fuel and a second fuel having a lower heat content per unit volume than the first fuel, Using a computer device, A step of determining the supply state of the second fuel to the combustor, A step of controlling the pilot fuel ratio, which is the fuel distribution ratio to the pilot fuel injection nozzle among the plurality of fuel injection nozzles of the combustor, It is possible to do this, A gas turbine control program controls the pilot fuel ratio to temporarily increase when it is determined that the supply state is cut off.

Images