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

Abstract

The present application relates to a gas turbine control device for controlling a gas turbine having a combustor capable of combusting a first fuel and a second fuel having a high combustion velocity. The device controls so that a mixing ratio of the second fuel becomes a target mixing ratio set in advance. In a case where it is determined that the mixing ratio is greater than a first reference value set to be greater than the target mixing ratio, the fuel flow rate of the second fuel is controlled so that the mixing ratio becomes less than a second reference value set to be less than the target mixing ratio.

Description

Technical Field

[0001] This invention relates to a gas turbine control device, a gas turbine control method, and a gas turbine control program.

[0002] This application claims priority based on Japanese Patent Application No. 2023-064706 filed with the Japan Patent Office on April 12, 2023, the contents of which are incorporated herein by reference. Background Technology

[0003] For example, in thermal power generation equipment, a gas turbine is used as the turbine to drive the generator, driven by combustion gases generated from fuel combustion. This gas turbine has a burner for burning fuel, and the amount of fuel supplied to the burner can be variably controlled according to the operating state of the gas turbine. For example, Patent Document 1 discloses a technology that, when it is determined that the calorific value of the fuel gas supplied to the burner has changed drastically, can continue operation without causing an emergency shutdown of the turbine by reducing the flow rate of the fuel gas.

[0004] Previous technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2014-240635 Summary of the Invention

[0007] The technical problem to be solved by the invention

[0008] However, in recent years, research has been conducted on improving power generation efficiency or actively utilizing fuels other than fossil fuels, such as hydrogen, as a way to reduce carbon dioxide (CO2) emissions, a cause of global warming, in thermal power plants. To reduce CO2 emissions, it is preferable to increase the co-firing ratio of the second fuel (hydrogen), which has a lower heat per unit volume compared to the first fuel (such as natural gas). However, hydrogen has a low ignition energy and a fast combustion rate; therefore, if the hydrogen co-firing ratio is too high, the possibility of backfire (flame backflow) or high-level combustion vibration increases. On the other hand, if the hydrogen co-firing ratio is too low, the heat input of the mixed fuel supplied to the burner is too high, leading to turbine inlet temperature overshoot, which also increases the possibility of backfire or high-level combustion vibration.

[0009] At least one embodiment of the present invention was made in view of the above circumstances, and its object is to provide a gas turbine control device, a gas turbine control method, and a gas turbine retrofitting method that can appropriately prevent backfire or high-level combustion vibration by appropriately controlling the co-combustion ratio of the fuel supplied to the burner.

[0010] means for solving technical problems

[0011] To address the aforementioned issues, at least one embodiment of the present invention relates to a gas turbine control device for controlling a gas turbine equipped with a burner capable of co-firing a first fuel and a second fuel with a combustion rate higher than that of the first fuel.

[0012] The gas turbine control device includes:

[0013] The mixing ratio acquisition unit is used to acquire the mixing ratio of the second fuel;

[0014] The mixing ratio control unit is used to control the mixing ratio in a way that makes the mixing ratio a preset target mixing ratio;

[0015] The mixing ratio determination unit is used to determine whether the mixing ratio is greater than a first reference value that is set to be greater than the target mixing ratio; and

[0016] The second fuel flow control unit is used to control the fuel flow rate of the second fuel.

[0017] When the second fuel flow control unit determines that the mixing ratio is greater than the first reference value, it controls the fuel flow of the second fuel in such a way that the mixing ratio is less than a second reference value that is set to be lower than the target mixing ratio.

[0018] To address the aforementioned issues, at least one embodiment of the present invention relates to a gas turbine control method for controlling a gas turbine equipped with a burner capable of co-firing a first fuel and a second fuel with a combustion rate higher than that of the first fuel.

[0019] The gas turbine control method includes the following steps:

[0020] Obtain the co-combustion ratio of the second fuel;

[0021] The mixing ratio is controlled in a way that makes the mixing ratio a pre-set target mixing ratio.

[0022] Determine whether the co-firing ratio is greater than a first reference value set to be greater than the target co-firing ratio; and

[0023] If it is determined that the mixing ratio is greater than the first reference value, the fuel flow rate of the second fuel is controlled in such a way that the mixing ratio is less than a second reference value that is set to be lower than the target mixing ratio.

[0024] To address the aforementioned issues, at least one embodiment of the present invention relates to a gas turbine control program for controlling a gas turbine equipped with a burner capable of co-firing a first fuel and a second fuel with a combustion rate higher than that of the first fuel.

[0025] The gas turbine control program causes the computer device to perform the following steps:

[0026] Obtain the co-combustion ratio of the second fuel;

[0027] The mixing ratio is controlled in a way that makes the mixing ratio a pre-set target mixing ratio.

[0028] Determine whether the co-firing ratio is greater than a first reference value set to be greater than the target co-firing ratio; and

[0029] If it is determined that the mixing ratio is greater than the first reference value, the fuel flow rate of the second fuel is controlled in such a way that the mixing ratio is less than a second reference value that is set to be lower than the target mixing ratio.

[0030] Invention Effects

[0031] According to at least one embodiment of the present invention, a gas turbine control device, a gas turbine control method, and a gas turbine modification method can be provided to appropriately prevent backfire or high-level combustion vibration by appropriately controlling the co-combustion ratio of the fuel supplied to the burner. Attached Figure Description

[0032] Figure 1 This is a diagram showing a schematic structure of a gas turbine according to one embodiment.

[0033] Figure 2 This is a block diagram illustrating the functional structure of a gas turbine control device according to one embodiment.

[0034] Figure 3 It is a time graph showing the time-varying changes in the load and co-firing ratio of the gas turbine when the co-firing ratio is greater than the first reference value. Detailed Implementation

[0035] Hereinafter, several embodiments of the present invention will be described with reference to the accompanying drawings. However, the structures described or illustrated as embodiments are not intended to limit the scope of the present invention, but are merely illustrative examples.

[0036] First, refer to Figure 1 The gas turbine, the controlled object of the gas turbine control device according to at least one embodiment of the present invention, will be described. Figure 1 This is a diagram showing a schematic structure of the gas turbine 1 according to one embodiment.

[0037] The gas turbine 1 includes a compressor 3 for generating compressed air, a burner 2 for generating combustion gases by mixing the compressed air generated by the compressor 3 with fuel, a fuel supply system 4 for supplying fuel to the burner 2, and a turbine 6 driven by the combustion gases. The compressor 3 and the turbine 6 are connected by a single shaft. In the gas turbine 1 with this structure, compressed air compressed by the compressor 3 and fuel supplied from the fuel supply system 4 are supplied to the burner 2, and these are mixed and burned to generate combustion gases. The combustion gases flow into the turbine 6, serving as the power source for driving the turbine 6.

[0038] Fuel supply system 4 processes a mixture of first fuel F1 and second fuel F2 as fuel supplied to burner 2. Second fuel F2 is a fuel with a higher combustion rate than first fuel F1. Furthermore, second fuel F2 has a lower calorific value per unit volume than first fuel F1. In this embodiment, first fuel F1 is liquefied natural gas (LNG), and second fuel F2 is hydrogen.

[0039] The first fuel F1 is supplied via the first fuel supply line 8 connected to the first fuel supply source 7. A flow meter 10 for detecting the flow rate of the first fuel F1 is provided on the first fuel supply line 8.

[0040] The second fuel F2 is supplied via the second fuel supply line 16 connected to the second fuel supply source 14. A flow meter 15 for detecting the flow rate of the second fuel F2 and a first flow regulating valve 18 for adjusting the flow rate of the second fuel F2 are provided on the second fuel supply line 16.

[0041] The first fuel supply line 8 and the second fuel supply line 16 converge at the downstream end and are connected to the mixing pipe 22. The first fuel F1 and the second fuel F2 are mixed by converging at the junction 25 of the first fuel supply line 8 and the second fuel supply line 16, and the mixed fuel (hereinafter appropriately referred to as "mixed fuel Fm") is transported through the mixing pipe 22.

[0042] In addition, a second flow regulating valve 26 is provided on the mixing pipe 22 for adjusting the flow rate of the mixed fuel Fm.

[0043] Although a detailed diagram is omitted from the downstream side of the mixing pipe 22, it branches off to multiple fuel injectors provided by the burner 2. These fuel injectors are premixed fuel injectors, which can form a flame by premixing the mixed fuel Fm supplied from the mixing pipe 22 with the combustion air supplied from the compressor 3 and then injecting it into the combustion chamber.

[0044] Next, the gas turbine control device 100 for controlling the gas turbine 1 having the above-described structure will be described. The gas turbine control device 100 is a control unit for controlling the gas turbine 1, and is composed, for example, of a CPU (Central Processing Unit), RAM (Random Access Memory), ROM (Read Only Memory), and a computer-readable storage medium. Furthermore, a series of processes for implementing various functions, as an example, are implemented by storing the program in a storage medium, etc., and the CPU reads the program into RAM, etc., and performs information processing and arithmetic to achieve various functions. Alternatively, the program may be pre-installed in ROM or other storage media, provided in a state stored in a computer-readable storage medium, or distributed via a wired or wireless communication unit. Computer-readable storage media refers to disks, optical disks, CD-ROMs, DVD-ROMs, semiconductor memories, etc.

[0045] Figure 2 This is a block diagram illustrating the functional structure of a gas turbine control device 100 according to one embodiment. The gas turbine control device 100 includes a combustion ratio acquisition unit 102, a target combustion ratio setting unit 104, a combustion ratio control unit 105, a combustion ratio determination unit 106, a decrease rate determination unit 108, an increase rate determination unit 110, and a second fuel flow control unit 112.

[0046] The mixing ratio acquisition unit 102 is configured to acquire the mixing ratio R of the second fuel F2 in the mixed fuel Fm. In this embodiment, the mixing ratio acquisition unit 102 is configured to acquire the flow rate measurement value of the first fuel F1 measured by the flow meter 10 disposed in the first fuel supply line 8 and the flow rate measurement value of the second fuel F2 measured by the flow meter 15 disposed in the second fuel supply line 16, and calculate the mixing ratio R based on these flow rate measurement values ​​by calculation.

[0047] In addition, the mixing rate acquisition unit 102 can obtain the calculation result of the mixing rate R from the outside, or it can obtain the measurement results of the flow meters 10 and 15 and perform the mixing rate R calculation by the mixing rate acquisition unit 102 itself to obtain the mixing rate R.

[0048] The target mixing ratio setting unit 104 is a structure for setting a target value (target mixing ratio Rt) related to the mixing ratio R. Although the target mixing ratio Rt is preset, it can be variably set according to the operating state of the gas turbine 1.

[0049] The mixing ratio control unit 105 is a structure for controlling the mixing ratio R of the second fuel F2. In this embodiment, the control of the mixing ratio R by the mixing ratio control unit 105 is achieved by adjusting the flow rate of the second fuel F2 in a manner that reduces the deviation ΔR between the mixing ratio R (measured value) obtained by the mixing ratio acquisition unit 102 and the target mixing ratio Rt. More specifically, the mixing ratio control unit 105 outputs an opening command value P as a control signal to the first flow regulating valve 18 disposed on the second fuel supply pipeline, thereby reducing the flow rate of the second fuel F2 for reducing the deviation ΔR from the target mixing ratio Rt.

[0050] The mixing ratio determination unit 106 is configured to determine whether the mixing ratio R acquired by the mixing ratio acquisition unit 102 is greater than a first reference value Ref1, which is set to be greater than a target mixing ratio Rt. The mixing ratio determination unit 106 performs the determination as follows: it acquires the mixing ratio R from the mixing ratio acquisition unit 102 at predetermined time intervals and compares the acquired mixing ratio R with the first reference value Ref1. For a specific control example regarding the case where the mixing ratio determination unit 106 determines that the mixing ratio R is greater than the first reference value Ref1, please refer to... Figure 3 The details will be provided later.

[0051] The rate reduction determination unit 108 is configured to determine whether the magnitude Cd of the rate reduction of the mixing ratio R acquired by the mixing ratio acquisition unit 102 is greater than the third reference value Ref3. The rate reduction determination unit 108 acquires the mixing ratio R from the mixing ratio acquisition unit 102 at predetermined time intervals, calculates the rate reduction based on the temporal trend of the mixing ratio R, and makes a determination by comparing the magnitude Cd of the rate reduction with the third reference value Ref3. Specific control examples regarding the case where the rate reduction determination unit 108 determines that the magnitude Cd of the rate reduction is greater than the third reference value Ref3 will be described later.

[0052] The increase rate determination unit 110 is configured to determine whether the increase rate of the mixing rate R acquired by the mixing rate acquisition unit 102 is greater than the fourth reference value Ref4. The increase rate determination unit 110 acquires the mixing rate R from the mixing rate acquisition unit 102 at predetermined time intervals, calculates the increase rate based on the temporal trend of the mixing rate R, and makes a determination by comparing the magnitude of the increase rate Ci with the fourth reference value Ref4. Specific control examples regarding the case where the increase rate determination unit 110 determines that the magnitude of the increase rate Ci is greater than the fourth reference value Ref4 will be described later.

[0053] The second fuel flow control unit 112 is a structure for controlling the flow rate of the second fuel F2 based on at least one of the determination results of the mixing ratio determination unit 106, the reduction rate determination unit 108, or the increase rate determination unit 110. Specifically, when at least one of the mixing ratio determination unit 106, the reduction rate determination unit 108, or the increase rate determination unit 110 makes a determination, the second fuel flow control unit 112 controls the fuel flow rate of the second fuel F2 such that the mixing ratio R is less than a second reference value Ref2 set to be lower than the target mixing ratio Rt. Therefore, when the mixing ratio R, the magnitude of the reduction rate Cd, or the magnitude of the increase rate Ci is too large, the generation of backfire or combustion vibration can be effectively suppressed by sufficiently reducing the mixing ratio R.

[0054] Additionally, the second benchmark value Ref2 can be 0%.

[0055] Next, refer to Figure 3 The operation of the gas turbine control device 100 having the above structure will be explained in detail.

[0056] first, Figure 3 This is a time graph showing the temporal changes in the load L and the mixing ratio R of the gas turbine 1 when the mixing ratio R is greater than the first reference value Ref1. In this example, the following situation is shown: up to time t1, the mixing ratio R is appropriately controlled by the mixing ratio control unit 105 to a target mixing ratio Rt that is set to be approximately constant. However, thereafter, due to some factor such as an anomaly in the second fuel supply source 14 or the second fuel supply line 16 of the fuel supply system 4, the mixing ratio R increases. As the mixing ratio R gradually increases, the deviation from the target mixing ratio Rt increases, and the first reference value Ref1 is reached at time t2. In this case, if the mixing ratio determination unit 106 determines that the mixing ratio R is greater than the first reference value Ref1, the second fuel flow control unit 112 controls the flow rate of the second fuel F2 to adjust the mixing ratio R to be less than the second reference value Ref2. In this embodiment, the control is performed as follows: from time t2 to time t3, the mixing ratio R is reduced at a predetermined rate.

[0057] When it is determined that the mixing ratio R is too large relative to the target mixing ratio Rt due to some factor causing the mixing ratio R to be greater than the first reference value Ref1, the mixing ratio R is controlled to be sufficiently smaller than the target mixing ratio Rt by adjusting the flow rate of the second fuel F2, thereby effectively suppressing the generation of backfire or high-level combustion vibration.

[0058] Furthermore, due to certain factors, there is a possibility that the flow rate of the second fuel F2 may decrease unexpectedly and drastically. In this case, the control of the valve opening of the second flow regulating valve 26 may not keep up, and since more of the first fuel F1 with higher heat per unit volume flows, the heat supplied to the combustor 2 will increase, the turbine inlet temperature may overshoot, and there is a risk of triggering backfire or high-level combustion vibration.

[0059] Therefore, the mixing ratio control unit 105 controls the mixing ratio Rt by adjusting the target mixing ratio Rt according to the magnitude of the rate of decrease Cd of the mixing ratio R. Specifically, it determines whether the magnitude of the rate of decrease Cd is greater than the third reference value Ref3. If it is determined to be greater than the third reference value Ref3, the second fuel flow control unit 112 controls the first flow regulating valve 18 by limiting the flow rate of the second fuel F2, thereby adjusting the mixing ratio R to be less than the second reference value Ref2. At the same time, the valve opening of the second flow regulating valve 26 is reduced so that the heat supplied to the burner 2 does not change.

[0060] Thus, when the rate of decrease of the mixing ratio R is too large (Cd), the mixing ratio R can be controlled to be sufficiently smaller than the target mixing ratio Rt by adjusting the flow rate of the second fuel F2, thereby effectively suppressing the generation of backfire or high-level combustion vibration.

[0061] Furthermore, due to certain factors, there is a possibility that the flow rate of the second fuel F2 may unexpectedly increase sharply. In this case, there is also a risk of generating a high level of combustion vibration in burner 2.

[0062] Therefore, the mixing ratio control unit 105 controls the target mixing ratio Rt by adjusting the target mixing ratio Rt according to the magnitude of the increase rate Ci of the mixing ratio R. Specifically, it determines whether the magnitude of the increase rate Ci is greater than the fourth reference value Ref4. If it is determined to be greater than the fourth reference value Ref4, the second fuel flow control unit 112 controls the first flow regulating valve 18 by limiting the flow rate of the second fuel F2, thereby adjusting the mixing ratio R to be less than the second reference value Ref2.

[0063] Thus, when the rate of increase of the mixing ratio R is too large, the mixing ratio R can be controlled to be sufficiently smaller than the target mixing ratio Rt by adjusting the flow rate of the second fuel F2, thereby effectively suppressing the generation of high-level combustion vibrations.

[0064] Furthermore, the constituent elements in the above embodiments can be appropriately replaced with known constituent elements without departing from the spirit of the present invention, and the above embodiments can be appropriately combined.

[0065] The contents described in the above embodiments can be understood as follows, for example.

[0066] (1) One method involves 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 with a combustion rate higher than that of the first fuel, the gas turbine control device comprising:

[0067] The mixing ratio acquisition unit is used to acquire the mixing ratio of the second fuel;

[0068] The mixing ratio control unit is used to control the mixing ratio so that it becomes a preset target mixing ratio;

[0069] The mixing ratio determination unit is used to determine whether the mixing ratio is greater than a first reference value that is set to be greater than the target mixing ratio; and

[0070] The second fuel flow control unit is used to control the fuel flow rate of the second fuel.

[0071] When the second fuel flow control unit determines that the mixing ratio is greater than the first reference value, it controls the fuel flow of the second fuel in such a way that the mixing ratio is less than a second reference value that is set to be lower than the target mixing ratio.

[0072] According to the method described in (1) above, when controlling the mixing ratio of the second fuel to a predetermined target mixing ratio, it is determined whether the mixing ratio is greater than a first reference value that is set to be greater than the target mixing ratio. As a result, if it is determined that the mixing ratio is greater than the first reference value, the flow rate of the second fuel is controlled to be less than the second reference value. In the case where the mixing ratio is too large relative to the target mixing ratio due to some factor, by adjusting the flow rate of the second fuel, the mixing ratio is controlled to be sufficiently less than the target mixing ratio, thereby effectively suppressing the generation of backfire or combustion vibration.

[0073] (2) In another manner, in the manner described in (1) above,

[0074] The heat per unit volume of the second fuel is less than that of the first fuel.

[0075] The gas turbine control device further includes a determination unit for determining whether the rate of decrease in the combustion ratio is greater than the rate of decrease of a third reference value.

[0076] When the second fuel flow control unit determines that the rate of decrease is greater than the third reference value, it controls the fuel flow of the second fuel in such a way that the co-firing ratio is less than the second reference value.

[0077] According to the above (2), during the period when the gas turbine is controlled in a way that makes the mixing ratio the target mixing ratio, when the mixing ratio shows a decreasing trend, it is determined whether the magnitude of its decreasing rate is greater than the third reference value.

[0078] As a result, if the rate of decrease is determined to be greater than the third reference value, the flow rate of the second fuel is controlled in such a way that the co-firing ratio is less than the second reference value.

[0079] In cases where the rate of decrease in the co-firing ratio is too large due to some factor, the co-firing ratio can be controlled to be sufficiently smaller than the target co-firing ratio by adjusting the flow rate of the second fuel, thereby effectively suppressing the generation of backfire or combustion vibration.

[0080] (3) In another manner, in the manner described in (2) above,

[0081] The second fuel flow control unit controls the fuel flow rate of the second fuel in such a way that the rate of decrease of the second fuel is less than the third reference value when the co-combustion ratio is less than the second reference value.

[0082] According to the above (3), when controlling the flow rate of the second fuel to decrease, the rate of decrease in the co-firing rate is adjusted to be less than the third reference value.

[0083] Therefore, it can effectively suppress the excessive rate of decrease in the co-firing ratio, which could lead to tempering or combustion vibration.

[0084] (4) In another embodiment, in any of the embodiments described in (1) to (3) above, a determination unit for determining whether the rate of increase of the co-firing ratio is greater than the rate of increase of the fourth reference value is further included.

[0085] When the second fuel flow control unit determines that the magnitude of the increase rate is greater than the fourth reference value, it controls the fuel flow of the second fuel in a manner that makes the co-combustion ratio less than the second reference value.

[0086] According to the above (4), during the period when the gas turbine is controlled in a way that makes the mixing ratio the target mixing ratio, when the mixing ratio shows an increasing trend, it is determined whether the magnitude of its increasing rate is greater than the fourth reference value.

[0087] As a result, if the rate of increase is determined to be greater than the fourth reference value, the flow rate of the second fuel is controlled in such a way that the co-firing ratio is less than the second reference value.

[0088] In cases where the rate of increase in the co-combustion ratio is excessive due to certain factors, adjusting the flow rate of the second fuel can control the co-combustion ratio to be sufficiently lower than the target co-combustion ratio, thereby effectively suppressing the generation of combustion vibration.

[0089] (5) In another manner, in any of the manners described in (1) to (4) above,

[0090] The gas turbine has:

[0091] A first fuel supply line is used to supply the first fuel;

[0092] A second fuel supply line for supplying the second fuel; and

[0093] A mixing line connects the junction of the first fuel supply line and the second fuel supply line to the burner.

[0094] The co-firing ratio is calculated based on the flow rate of the first fuel in the first fuel supply line and the flow rate of the second fuel in the second fuel supply line.

[0095] According to the above (5) method, the co-firing ratio for the above control can be appropriately obtained as a calculated value based on the flow rates of the first fuel and the second fuel in the first fuel supply line and the second fuel supply line, respectively.

[0096] (6) In another manner, in any of the manners described in (1) to (5) above,

[0097] The first fuel is natural gas.

[0098] The second fuel is hydrogen.

[0099] According to the above (6), in a gas turbine equipped with a burner capable of burning a mixture of fuels including natural gas and hydrogen, backfire or combustion vibration can be appropriately prevented by properly controlling the mixing ratio of the fuel supplied to the burner.

[0100] (7) A gas turbine control method according to one aspect is used to control a gas turbine having a burner capable of co-firing a first fuel and a second fuel with a combustion rate higher than that of the first fuel, the gas turbine control method comprising the following steps:

[0101] Obtain the co-combustion ratio of the second fuel;

[0102] The mixing ratio is controlled in a way that makes the mixing ratio a pre-set target mixing ratio.

[0103] Determine whether the co-firing ratio is greater than a first reference value set to be greater than the target co-firing ratio; and

[0104] If it is determined that the mixing ratio is greater than the first reference value, the fuel flow rate of the second fuel is controlled in such a way that the mixing ratio is less than a second reference value that is set to be lower than the target mixing ratio.

[0105] According to the method described in (7) above, when controlling the mixing ratio of the second fuel to a predetermined target mixing ratio, it is determined whether it is greater than a first reference value that is set to be greater than the target mixing ratio. As a result, if it is determined that the mixing ratio is greater than the first reference value, the flow rate of the second fuel is controlled to be less than the second reference value. In the case where the mixing ratio is too large relative to the target mixing ratio due to some factor, by adjusting the flow rate of the second fuel, the mixing ratio is controlled to be sufficiently less than the target mixing ratio, thereby effectively suppressing the generation of backfire or combustion vibration.

[0106] (8) A gas turbine control program according to one method is used to control a gas turbine having a burner capable of co-firing a first fuel and a second fuel with a combustion rate higher than that of the first fuel, the gas turbine control program causing a computer device to perform the following steps:

[0107] Obtain the co-combustion ratio of the second fuel;

[0108] The mixing ratio is controlled in a way that makes the mixing ratio a pre-set target mixing ratio.

[0109] Determine whether the co-firing ratio is greater than a first reference value set to be greater than the target co-firing ratio; and

[0110] If it is determined that the mixing ratio is greater than the first reference value, the fuel flow rate of the second fuel is controlled in such a way that the mixing ratio is less than a second reference value that is set to be lower than the target mixing ratio.

[0111] According to the method described in (8) above, when controlling the mixing ratio of the second fuel to a predetermined target mixing ratio, it is determined whether it is greater than a first reference value that is set to be greater than the target mixing ratio. As a result, if it is determined that the mixing ratio is greater than the first reference value, the flow rate of the second fuel is controlled to be less than the second reference value. In the case where the mixing ratio is too large relative to the target mixing ratio due to some factor, by adjusting the flow rate of the second fuel, the mixing ratio is controlled to be sufficiently less than the target mixing ratio, thereby effectively suppressing the generation of backfire or combustion vibration.

[0112] Symbol Explanation

[0113] 1-Gas turbine, 2-Burner, 3-Compressor, 6-Turbine, 7-First fuel supply source, 8-First fuel supply line, 10-Flow meter, 14-Second fuel supply source, 15-Flow meter, 16-Second fuel supply line, 18-First flow regulating valve, 22-Mixing pipe, 25-Merging point, 26-Second flow regulating valve, 100-Gas turbine control unit, 102-Mixing rate acquisition unit, 104-Target mixing rate setting unit, 105-Mixing rate control unit, 106-Mixing rate determination unit, 108-Decrease rate determination unit, 110-Increase rate determination unit, 112-Second fuel flow control unit.

Claims

1. A gas turbine control device for controlling a gas turbine having a combustor capable of co-firing a first fuel and a second fuel with a combustion rate higher than that of the first fuel, the gas turbine control device comprising: The mixing ratio acquisition unit is used to acquire the mixing ratio of the second fuel; The mixing ratio control unit is used to control the mixing ratio in a way that makes the mixing ratio a preset target mixing ratio; The mixing ratio determination unit is used to determine whether the mixing ratio is greater than a first reference value that is set to be greater than the target mixing ratio; and The second fuel flow control unit is used to control the fuel flow rate of the second fuel. When the second fuel flow control unit determines that the mixing ratio is greater than the first reference value, it controls the fuel flow of the second fuel in such a way that the mixing ratio is less than a second reference value that is set to be lower than the target mixing ratio.

2. The gas turbine control device according to claim 1, wherein, The heat per unit volume of the second fuel is less than that of the first fuel. The gas turbine control device further includes a determination unit for determining whether the rate of decrease in the combustion ratio is greater than the rate of decrease of a third reference value. When the second fuel flow control unit determines that the rate of decrease is greater than the third reference value, it controls the fuel flow of the second fuel in such a way that the co-firing ratio is less than the second reference value.

3. The gas turbine control device according to claim 2, wherein, The second fuel flow control unit controls the fuel flow rate of the second fuel in such a way that the rate of decrease of the second fuel is less than the third reference value when the co-combustion ratio is less than the second reference value.

4. The gas turbine control device according to claim 1 or 2, further comprising: The determination unit for determining whether the rate of increase of the co-firing ratio is greater than the rate of increase of the fourth reference value. When the second fuel flow control unit determines that the magnitude of the increase rate is greater than the fourth reference value, it controls the fuel flow of the second fuel in a manner that makes the co-firing ratio less than the second reference value.

5. The gas turbine control device according to claim 1 or 2, wherein, The gas turbine has: A first fuel supply line is used to supply the first fuel; A second fuel supply line for supplying the second fuel; and A mixing line connects the junction of the first fuel supply line and the second fuel supply line to the burner. The co-firing ratio is calculated based on the flow rate of the first fuel in the first fuel supply line and the flow rate of the second fuel in the second fuel supply line.

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

7. A gas turbine control method for controlling a gas turbine having a combustor capable of co-firing a first fuel and a second fuel with a combustion rate higher than that of the first fuel, the gas turbine control method comprising the following steps: Obtain the co-combustion ratio of the second fuel; The mixing ratio is controlled in a way that makes the mixing ratio a pre-set target mixing ratio. Determine whether the co-firing ratio is greater than a first reference value set to be greater than the target co-firing ratio; and If it is determined that the mixing ratio is greater than the first reference value, the fuel flow rate of the second fuel is controlled in such a way that the mixing ratio is less than a second reference value that is set to be lower than the target mixing ratio.

8. A gas turbine control program for controlling a gas turbine having a burner capable of co-firing a first fuel and a second fuel with a combustion rate higher than that of the first fuel, the gas turbine control program causing a computer device to perform the following steps: Obtain the co-combustion ratio of the second fuel; The mixing ratio is controlled in a way that makes the mixing ratio a pre-set target mixing ratio. Determine whether the co-firing ratio is greater than a first reference value set to be greater than the target co-firing ratio; and If it is determined that the mixing ratio is greater than the first reference value, the fuel flow rate of the second fuel is controlled in such a way that the mixing ratio is less than a second reference value that is set to be lower than the target mixing ratio.

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