OPERATING METHOD FOR A GAS TURBINE AND CONTROL DEVICE FOR A GAS TURBINE

Abstract

An operating method for a gas turbine according to at least one embodiment of the present disclosure is an operating method for a gas turbine, comprising: a step of increasing a co-firing ratio of a first fuel whose co-firing ratio is to be increased and a second fuel different from the first fuel. The step of increasing the co-firing ratio includes changing at least one of a turbine inlet temperature and a change rate of the co-firing ratio based on information regarding a relationship between the turbine inlet temperature and the co-firing ratio.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to an operating method for a gas turbine and a control device for the gas turbine. BACKGROUND

[0002] It is known that in a gas turbine, multiple kinds of fuel, such as less combustible fuel and highly combustible fuel, are burned in a combustion chamber by changing the ratio of the supply amounts (see, for example, Patent Document 1). List of reference symbolsPatent literature

[0003] Patent Document 1: WO2022 / 149540A SUMMARY

[0004] When combusting multiple fuel types by changing the feed ratio, as in the combustion chamber described in the above-described patent, the amount of unburned fuel generated may increase during the process of changing the feed ratio depending on the type of combustion. The generation of unburned fuel leads to a reduction in the efficiency of the gas turbine. Therefore, it is desirable to minimize the amount of unburned fuel generated.

[0005] In view of the above, an object of at least one embodiment of the present disclosure is to provide an operating method for a gas turbine and a control apparatus for the gas turbine capable of reducing an increase in the amount of unburned fuel generated.

[0006] (1) An operating method for a gas turbine according to at least one embodiment of the present disclosure is an operating method for a gas turbine, including a step of increasing a co-firing ratio of a first fuel whose co-firing ratio is to be increased and a second fuel different from the first fuel. The step of increasing the co-firing ratio includes changing at least one of a turbine inlet temperature and a change rate of the co-firing ratio based on information regarding a relationship between the turbine inlet temperature and the co-firing ratio.

[0007] (2) An operating method for a gas turbine according to at least one embodiment of the present disclosure is an operating method for a gas turbine, including a step of increasing a co-firing ratio of a first fuel whose co-firing ratio is to be increased and a second fuel different from the first fuel. The gas turbine includes a sensor for detecting unburned fuel of the first fuel in a combustion gas. The step of increasing the co-firing ratio includes changing at least one of a turbine inlet temperature and a change rate of the co-firing ratio when it is determined that a concentration of the unburned fuel of the first fuel in the combustion gas detected by the sensor has increased based on the concentration.

[0008] (3) A control unit for a gas turbine according to at least one embodiment of the present disclosure is a control unit for a gas turbine, including: a co-firing ratio control unit configured to increase a co-firing ratio of a first fuel whose co-firing ratio is to be increased and a second fuel different from the first fuel. The co-firing ratio control unit is configured to change at least one of a turbine inlet temperature and a change rate of the co-firing ratio when increasing the co-firing ratio based on information regarding a relationship between the turbine inlet temperature and the co-firing ratio.

[0009] According to at least one embodiment of the present disclosure, it is possible to reduce an increase in the amount of unburned fuel generated. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic diagram of the configuration of a gas turbine according to an embodiment. Fig. 2 is a functional block diagram of a controller according to some embodiments. Fig. Figure 3 is a diagram describing the relationship between turbine inlet temperature and co-firing ratio. Fig. 4 is a flowchart illustrating a processing process in a method for operating the gas turbine according to some embodiments. Fig. 5A is a diagram showing a transition of the concentration of unburned ammonia during execution of a step of increasing the co-firing ratio in the operating method for a gas turbine according to the first embodiment. Fig. 5B is a diagram showing a transition of the co-firing ratio during execution of the step of increasing the co-firing ratio and a transition of the increasing rate of the co-firing ratio in the operating method for a gas turbine according to the first embodiment. Fig. 5C is a diagram showing a transition of an ammonia flow rate during execution of the step of increasing the co-firing ratio in the operating method for a gas turbine according to the first embodiment. Fig. 5D is a diagram showing a transition of a natural gas flow rate during execution of the step of increasing the co-firing ratio in the operating method for a gas turbine according to the first embodiment. Fig. 5E is a diagram showing a transition of the turbine inlet temperature during execution of the step of increasing the co-firing ratio in the operating method for a gas turbine according to the first embodiment. Fig. 6A is a diagram showing a transition of the concentration of unburned ammonia during the execution of the step of increasing the co-firing ratio in the operating method for a gas turbine according to the third embodiment. Fig. 6B is a diagram showing a transition of the co-firing ratio increasing rate during execution of the co-firing ratio increasing step in the gas turbine operating method according to the third embodiment. Fig. 6C is a diagram showing a transition of the co-firing ratio during execution of the step of increasing the co-firing ratio in the operating method for a gas turbine according to the third embodiment. DETAILED DESCRIPTION

[0010] Some embodiments of the present disclosure will be described below with reference to the accompanying drawings. However, dimensions, materials, shapes, relative positions, and the like of components described or shown in the drawings as embodiments are intended to be illustrative only and are not intended to limit the scope of the present disclosure unless specifically identified.

[0011] For example, an expression for a relative or absolute arrangement such as "in one direction", "along one direction", "parallel", "orthogonal", "centered", "concentric" and "coaxial" should not be construed as meaning only the arrangement in the strict sense of the word, but also as including a condition in which the arrangement is relatively displaced by a tolerance or by an angle or a distance, whereby it is possible to achieve the same function.

[0012] For example, an expression for an equal state such as "equal", "same" and "uniform" should not be interpreted as indicating only the state in which the characteristic is strictly the same, but also a state in which there is a tolerance or a difference that can still achieve the same function.

[0013] In addition, for example, a shape such as a rectangular shape or a tubular shape is not only to be understood as the geometrically strict shape, but also includes a shape with bumps or beveled corners within the range where the same effect can be achieved.

[0014] On the other hand, the terms “comprising”, “including”, “with”, “containing” and “consisting of” a component are not exclusive terms that exclude the presence of other components. (Overall configuration of gas turbine 2)

[0015] An example of a gas turbine 2 with a control device 100 for the gas turbine according to some embodiments is described below. Fig. 1 is a diagram schematically showing the configuration of the gas turbine 2 according to an embodiment. As shown in Fig. 1, a power generation device 1 comprises the gas turbine 2 and a generator 7.

[0016] Fig. Figure 1 mainly shows a configuration related to the gas turbine operating method described later, and omits the illustration of other configurations.

[0017] The gas turbine 2 is, for example, a gas turbine for power generation. The gas turbine 2 comprises a compressor 3 for generating compressed air, a combustion chamber 4 for generating a combustion gas from the compressed air and fuel, a turbine 5 configured to be rotated by the combustion gas, and a fuel system 20 for supplying the combustion chamber 4 with fuel.

[0018] The compressor 3 is connected to the turbine 5 via a rotating shaft 8A. The compressor 3 is rotated by the rotational energy of the turbine 5 to generate compressed air. A vane 6 is arranged on an inlet side of the compressor 3. The amount of incoming air is adjusted by changing the opening degree of the inlet guide vane 6 with an actuator 6a. The opening degree of the inlet guide vanes 6 is controlled based on an IGVCSO control command for the opening degree of the inlet guide vanes. The compressed air generated by the compressor 3 is supplied to the combustion system 4.

[0019] The combustion chamber 4 is supplied with fuel and the compressed air generated by the compressor 3 and combusts the fuel to generate the combustion gas, which serves as the working fluid for the turbine 5. In the gas turbine 2 according to one embodiment, a first fuel F1 and a second fuel F2 different from the first fuel F1 can be combusted in the combustion chamber 4.

[0020] The turbine 5 is driven by the combustion gas generated by the combustion chamber 4. The turbine 5 is connected to the generator 7 via a rotating shaft 8B. The generator 7 is configured to generate electricity using the rotational energy of the turbine 5.

[0021] A concentration sensor 9 for detecting the ammonia concentration in the combustion gas is arranged in an exhaust gas duct 5a of the turbine 5. (Fuel system 20)

[0022] In the gas turbine 2 according to one embodiment, the fuel system 20 is configured to supply the first fuel F1 and the second fuel F2, which is different from the first fuel F1, to the combustion chamber 4. According to one embodiment, the fuel system 20 includes a first fuel supply system 21 for supplying the first fuel F1 to the combustion chamber 4 and a second fuel supply system 22 for supplying the second fuel F2 to the combustion chamber 4.

[0023] In the gas turbine 2 according to one embodiment, the first fuel F1 is, for example, ammonia and the second fuel F2 is, for example, natural gas, but the first fuel F1 may also be other than ammonia and the second fuel F2 may be other than natural gas, as long as the second fuel F2 is a different fuel than the first fuel F1.

[0024] According to one embodiment, the first fuel supply system 21 of the fuel system 20 comprises a first fuel flow control valve 23 for controlling the amount of the first fuel F1 supplied to the combustion chamber 4.

[0025] According to one embodiment, the second fuel supply system 22 of the fuel system 20 comprises a second fuel flow control valve 25 for controlling the amount of the second fuel F2 supplied to the combustion chamber 4.

[0026] The first fuel flow control valve 23 includes an actuator (not shown) for controlling the flow rate of the first fuel F1 flowing through the first fuel flow control valve 23. Similarly, the second fuel flow control valve 25 includes an actuator (not shown) for controlling the flow rate of the second fuel F2 flowing through the second fuel flow control valve 25.

[0027] In the fuel system 20 according to one embodiment, the actuators (not shown) of the first fuel flow control valve 23 and the second fuel flow control valve 25 are controlled by the controller 100 according to some embodiments. (Control unit 100)

[0028] The control device 100 according to some embodiments includes a processor 101 for performing various types of arithmetic processing and a memory 103 for non-temporarily or temporarily storing various data processed by the processor 101. The processor 101 is implemented by a CPU, GPU, MPU, DSP, various types of computing devices other than these, a combination of these, or the like. The memory 103 is implemented by ROM, RAM, flash memory, a combination of these, or the like.

[0029] Fig. 2 is a functional block diagram of the controller 100 according to some embodiments. Fig. 2 shows only functional blocks related to controlling the flow rates of the first fuel F1 and the second fuel F2, which will be described later, and omits the illustration of other functional blocks.

[0030] The control device 100 according to some embodiments includes a co-firing ratio control unit 110 configured to increase the co-firing ratio of the first fuel F1, whose co-firing ratio is to be increased, and the second fuel F2, which is different from the first fuel F1. The co-firing ratio control unit 110 includes a fuel flow calculation unit 111 and a valve control output signal output unit 112. The co-firing ratio control unit 110, the fuel flow calculation unit 111, and the valve control output signal output unit 112 are functional blocks implemented by the processor 101, which executes the programs stored in the memory 103.

[0031] The fuel flow rate calculation unit 111 calculates the flow rates of the first fuel F1 and the second fuel F2 supplied to the combustion chamber 4 from the first fuel supply system 21 and the second fuel supply system 22, as described later.

[0032] The valve control signal output unit 112 outputs control signals to the actuators (not shown) of the first fuel flow control valve 23 and the second fuel flow control valve 25 so that the first fuel F1 and the second fuel F2 are supplied to the combustion chamber 4 at the flow rates calculated by the fuel flow calculation unit 111.

[0033] In the control device 100 according to some embodiments, the co-firing ratio control unit 110 is configured to, when the above-described co-firing ratio is increased, change at least one of a turbine inlet temperature T1T and the change rate of the co-firing ratio based on the information regarding the relationship between the turbine inlet temperature T1T and the above-described co-firing ratio, as described later.

[0034] In particular, the processing contents in the control unit 100 will be described in detail later. (To control the co-firing ratio)

[0035] In some embodiments, the gas turbine 2 is started with a single firing of natural gas, i.e., the second fuel F2. After the turbine inlet temperature T1T reaches a target temperature, the fuel supply to the combustor 4 is switched to a single firing of the first fuel F1 by increasing the first fuel F1 and decreasing the second fuel F2.

[0036] That is, in the gas turbine 2 according to some embodiments, during the period from the time the gas turbine 2 is started by single firing of the second fuel F2 and the turbine inlet temperature T1T reaches the target temperature until the time it switches to single firing of the first fuel F1, the co-firing ratio (calorie ratio) of the first fuel F1 to the total fuel supplied to the combustor 4 is gradually increased from 0% to 100%. In the present disclosure, the co-firing ratio (calorie ratio) of the first fuel F1 to the total fuel supplied to the combustor 4 is also simply referred to as the co-firing ratio.

[0037] Fig. 3 is a graph for describing a relationship between the turbine inlet temperature and the co-firing ratio, where the horizontal axis represents the co-firing ratio and the vertical axis represents the turbine inlet temperature T1T.

[0038] The thin solid curve line L2 in Fig. 3 is a curve line indicating a limit for whether unburned fuel is generated from ammonia, which is the first fuel F1 in the combustion gas. In the following description, the unburned fuel of the first fuel F1 in the combustion gas is also simply referred to as unburned fuel, and the concentration of the unburned fuel of the first fuel F1 in the combustion gas is also simply referred to as the unburned fuel concentration.

[0039] An area on the lower right side of the graphic line L2 in Fig. 3 is an area where the unburned fuel is generated, and an area on the upper left side of the graphic line L2 in Fig. 3 is an area where the unburned fuel is not generated. In addition, the concentration of the unburned fuel in the area on the lower right side of the graphic line L2 decreases in Fig. 3 increases with increasing distance from the graphic line L2.

[0040] The curve line L2 is a curve line determined in advance by a test, etc.

[0041] As described above, as a result of intensive investigations by the present inventors, it was found that the relationship between the turbine inlet temperature T1T and the co-firing ratio affects the concentration of unburned fuel.

[0042] For example, when the co-firing ratio is increased while the turbine inlet temperature T1T is maintained at a temperature Ta, the curve line L1 touches the curve line L2 when the co-firing ratio reaches a value M1, as shown by a thick solid curve line L1 in the diagram of Fig. 3 is displayed.

[0043] If the co-firing ratio is further increased while the turbine inlet temperature T1T is maintained at temperature Ta, the graphic line L1 reaches the area on the lower right side of the graphic line L2, as indicated by a dashed line. Therefore, if the co-firing ratio exceeds the value M1 while the turbine inlet temperature T1T is at temperature Ta, unburned fuel is generated, the concentration of which gradually increases with the increase of the co-firing ratio.

[0044] As a result of intensive investigations by the present inventors, it was found that when an increase in the amount of unburned fuel generated is expected with the above-described increase in the co-firing ratio, the increase in the amount of unburned fuel generated can be reduced by increasing the turbine inlet temperature T1T or reducing the rate of change of the co-firing ratio.

[0045] Therefore, in the operating method for a gas turbine according to some embodiments, when increasing the co-firing ratio, at least one of the turbine inlet temperature T1T and the rate of change of the co-firing ratio is adjusted based on the information regarding the relationship between the turbine inlet temperature T1T and the co-firing ratio, as shown in the diagram of Fig. 3 shown, modified as described later.

[0046] This makes it possible to reduce the increase in the amount of unburned fuel.

[0047] It is assumed that the information about the relationship between the turbine inlet temperature T1T and the co-firing ratio, as shown in the diagram in Fig. 3 are stored in advance in the memory 103 of the control device 100.

[0048] The information about the relationship between the turbine inlet temperature T1T and the co-firing ratio as shown in the graph of Fig. 3 can be a map of the turbine inlet temperature T1T and the co-firing ratio as shown in the graph of Fig. 3 is shown.

[0049] It is relatively easy to control the turbine inlet temperature T1T or the rate of change of the co-firing ratio.

[0050] Since the concentration of unburned fuel increases with increasing distance from the graphic line L2 of Fig. 3 in the area on the lower right side of the graphic line L2, as described above, the information regarding the relationship between the turbine inlet temperature T1T and the co-firing ratio, as shown in the graphic representation of Fig. 3, also information regarding a relationship between the turbine inlet temperature T1T, the co-firing ratio and the concentration of the unburned fuel.

[0051] Furthermore, the information about the relationship between the turbine inlet temperature T1T and the co-firing ratio, as shown in the graph of Fig. 3, be a function of the relationship between the turbine inlet temperature T1T, the co-firing ratio and the concentration of the unburned fuel.

[0052] Therefore, in the operating method for a gas turbine according to some embodiments, the increase in the generated amount of unburned fuel can be reduced by controlling at least one of the turbine inlet temperature T1T and the change rate of the co-firing ratio based on the information regarding the relationship between the turbine inlet temperature T1T, the co-firing ratio, and the concentration of the unburned fuel, as shown in the diagram of Fig. 3 shown, is changed.

[0053] Fig. 4 is a flowchart showing a processing procedure in the operating method for a gas turbine according to some embodiments. In the operating method for a gas turbine according to some embodiments, when the gas turbine 2 is started by single firing of the second fuel F2 and the turbine inlet temperature T1T reaches the target temperature, the processor 101 of the control device 100 reads from the memory 103 the program for executing a control procedure shown in the flowchart of Fig. 4 process and executes the program.

[0054] The method for operating the gas turbine according to some embodiments includes step S10 of increasing the co-firing ratio.

[0055] In the operating method for a gas turbine according to some embodiments, the step S10 of increasing the co-firing ratio is a step of increasing the co-firing ratio of the first fuel F1 whose co-firing ratio is to be increased and the second fuel F2 which is different from the first fuel F1.

[0056] The processing contents in step S10 of increasing the co-firing ratio are described below. (Regarding the operational method for the gas turbine in the first embodiment)

[0057] Fig. 5A is a diagram showing a transition of the unburned fuel concentration, ie, the unburned ammonia concentration, during the execution of step S10 of increasing the co-firing ratio in the operating method for a gas turbine according to the first embodiment.

[0058] Fig. 5B is a diagram showing a transition of the co-firing ratio during the execution of step S10 of increasing the co-firing ratio and a transition of the increasing rate of the co-firing ratio in the operating method for a gas turbine according to the first embodiment.

[0059] Fig. 5C is a diagram showing a transition of an ammonia flow rate, which is the amount of the first fuel F1 supplied to the combustor 4 during execution of step S10 of increasing the co-firing ratio in the operating method for a gas turbine according to the first embodiment.

[0060] Fig. 5D is a diagram showing a transition of a natural gas flow rate representing the amount of the second fuel F2 supplied to the combustor 4 during the execution of step S10 of increasing the co-firing ratio in the operating method for a gas turbine according to the first embodiment.

[0061] Fig. 5E is a diagram showing a transition of the turbine inlet temperature T1T during the execution of step S10 of increasing the co-firing ratio in the operating method for a gas turbine according to the first embodiment.

[0062] In the operating method for a gas turbine according to the first embodiment, as described below, in step S10 of increasing the co-firing ratio, the turbine inlet temperature T1T is changed so that the concentration of the unburned fuel in the combustion gas does not exceed a certain concentration, based on the information regarding the relationship between the turbine inlet temperature T1T and the co-firing ratio, as shown in the graph of Fig. 3 shown.

[0063] In the method for operating the gas turbine according to the first embodiment, in step S10 of increasing the co-firing ratio, the control unit 110 of the control device 100 increases the co-firing ratio at the co-firing ratio increasing rate at a certain constant increasing rate from the start to the end of the execution of step S10 of increasing the co-firing ratio, that is, from the co-firing ratio of 0% to 100%, as shown by the graphic lines L4 and L5 in Fig. 5B is displayed.

[0064] Further, in the operating method for a gas turbine according to the first embodiment, it is assumed that the co-firing ratio reaches 100% when a time Te has elapsed since the start of execution of step S10.

[0065] To simplify the description, it is assumed that the turbine inlet temperature T1T at the beginning of step S10 of increasing the co-firing ratio is equal to the temperature Ta in Fig. corresponds.

[0066] In the operating method for a gas turbine according to the first embodiment, in step S10 of increasing the co-firing ratio, the fuel flow rate calculation unit 111 of the control unit 100 calculates the flow rates of the first fuel F1 and the second fuel F2 supplied from the first fuel supply system 21 and the second fuel supply system 22 to the combustion chamber 4 so that the co-firing ratio increases at a constant rate of increase of the co-firing ratio while the turbine inlet temperature T1T is maintained at the temperature Ta, as shown by a graphic line L8 in Fig. 5E. Then, the valve control signal output unit 112 of the control device 100 outputs the control signals to the actuators (not shown) of the first fuel flow control valve 23 and the second fuel flow control valve 25, so that the first fuel F1 and the second fuel F2 are supplied to the combustion chamber 4 at the flow rates calculated by the fuel flow calculation unit 111.

[0067] As a result, the ammonia flow rate, which represents the amount of the first fuel F1 supplied to the combustion chamber 4, gradually increases with the passage of time, as shown by a graphic line L6 in Fig. 5C, and the natural gas flow rate, which represents the amount of the second fuel F2 supplied to the combustion chamber 4, gradually decreases with the passage of time, as shown in Fig. 5D shown.

[0068] Consequently, in the turbine 5, the co-firing ratio increases at the constant rate of increase of the co-firing ratio while the turbine inlet temperature T1T is maintained at the temperature Ta.

[0069] The dashed diagram lines Lt1, Lt2, Lt3 and Lt4 in Fig. 5C are graph lines representing the transitions of the ammonia flow rate when the co-firing ratio is increased with the co-firing ratio increasing rate at a certain constant increase rate while the turbine inlet temperature T1T is maintained at a certain temperature. The turbine inlet temperature T1T is maintained at different temperatures in the graph lines Lt1, Lt2, Lt3, and Lt4, respectively, and the higher the graph line in Fig. 5C, the higher the maintained turbine inlet temperature T1T.

[0070] The dashed diagram lines Lt5, Lt6, Lt7 and Lt8 in Fig. 5D are graph lines representing transitions of the natural gas rate when the co-firing ratio is increased at a certain constant rate while the turbine inlet temperature T1T is maintained at a certain temperature. The turbine inlet temperature T1T is maintained at different temperatures in the graph lines Lt5, Lt6, Lt7, and Lt8, respectively, and the higher the graph line in Fig. 5D, the higher the maintained turbine inlet temperature T1T.

[0071] In the operating method for a gas turbine according to the first embodiment, it is assumed that the graphic line L1 in Fig. 3, the graphical line L2 touches shortly after the time T1 that has elapsed since the start of the execution of step S10 of increasing the co-firing ratio. That is, in the operating method for a gas turbine according to the first embodiment, it is assumed that when step S10 of increasing the co-firing ratio is executed while the turbine inlet temperature T1T is maintained at the temperature Ta, the co-firing ratio reaches the value M1 in Fig. 3 shortly after the time T1 has elapsed since the start of the execution of step S10. Therefore, shortly after the time T1 has elapsed, the generation of unburned fuel begins, as shown by a dashed line section of a diagram line L3 in Fig. 5A is displayed.

[0072] Therefore, in the gas turbine operating method according to the first embodiment, in step S10 of increasing the co-firing ratio, the fuel flow rate calculation unit 111 calculates the flow rates of the first fuel F1 and the second fuel F2 supplied from the first fuel supply system 21 and the second fuel supply system 22 to the combustion chamber 4 so that the turbine inlet temperature T1T is gradually increased so that the unburned fuel does not exceed the predetermined concentration. Then, the valve control signal output unit 112 of the control device 100 outputs the control signals to the actuators (not shown) of the first fuel flow control valve 23 and the second fuel flow control valve 25 so that the first fuel F1 and the second fuel F2 are supplied to the combustion chamber 4 at the flow rates calculated by the fuel flow rate calculation unit 111.

[0073] In the operating method for a gas turbine according to the first embodiment, each unit is controlled so that the curve line L1 in Fig. remains in the upper left area of ​​the curve line L2.

[0074] In the operating method for a gas turbine according to the first embodiment, in step S10 of increasing the co-firing ratio, the control unit 110 of the control device 100 controls the turbine inlet temperature T1T such that the turbine inlet temperature T1T becomes a first temperature, for example, when it is determined that the concentration of the unburned fuel does not exceed the predetermined concentration as before the lapse of time T1, based on the information regarding the relationship between the turbine inlet temperature T1T and the co-firing ratio as shown in the graph of Fig. 3. In step S10 of increasing the co-firing ratio, the control unit 110 of the control device 100 preferably controls the turbine inlet temperature T1T so that the turbine inlet temperature T1T becomes a second temperature higher than the first temperature, for example, when it is determined that the concentration of the unburned fuel is about to exceed the predetermined concentration after the lapse of time T1, based on the information described above.

[0075] The first temperature described above can be, for example, the temperature Ta, which is represented by the graphic line L1 in Fig. 3 is displayed when the co-firing ratio is below the value M1. The second temperature described above can, for example, be the temperature indicated by the graphic line L1 in Fig. 3 is displayed when the co-firing ratio is higher than the value M1.

[0076] The first and second temperatures described above can be fixed or variable values.

[0077] In the operating method for a gas turbine according to the first embodiment, the turbine inlet temperature T1T can be gradually increased by, for example, performing the control described above.

[0078] Furthermore, with the operating method for a gas turbine according to the first embodiment, by increasing the turbine inlet temperature T1T, the concentration of the unburned fuel in the combustion gas can be prevented from exceeding the predetermined concentration, as shown by a solid part of the graph line L3 in Fig. 5A shown.

[0079] The solid part of the diagram line L3 in Fig. 5A is shown as a state where no unburned fuel is generated. However, the solid part of the graphic line L3 may be in a range where the concentration is not greater than the specified concentration.

[0080] In the gas turbine operating method according to the first embodiment, the curve line L1 can remain in the upper left region of the curve line L2 even when the co-firing ratio reaches the value M1 described above. The same applies to the gas turbine operating method according to the second embodiment, which will be described later.

[0081] Before the co-firing ratio reaches the value M1 in Fig. 3, the turbine inlet temperature T1T increases with increasing co-firing ratio as indicated by the graphic line L1, and the graphic line L1 is located in the area on the upper left side of the graphic line L2 even after the co-firing ratio reaches the value M1, which can prevent the generation of the unburned fuel.

[0082] In the gas turbine operating method according to the first embodiment, after the co-firing ratio reaches M1, the turbine inlet temperature T1T is preferably changed so that the curve L1 does not enter a region where the unburned fuel concentration is relatively high, that is, so that the curve L1 does not enter a region relatively far from the curve L2. The same applies to the gas turbine operating method according to the second embodiment, which will be described later.

[0083] This makes it possible to reduce the increase in the amount of unburned fuel.

[0084] As an example of the stepwise increase of the turbine inlet temperature T1T, in the operating method for a gas turbine according to the first embodiment, the co-firing ratio control unit 110 controls each unit so that an increase rate Sam of the flow rate of the first fuel F1 becomes a first increase rate Sam1 before the time T1 has elapsed, and controls each unit so that the increase rate Sam of the flow rate of the first fuel F1 becomes a second increase rate Sam2 that is larger than the first increase rate Sam1 after the time T1 has elapsed, for example.

[0085] Consequently, the ammonia flow rate, ie the amount of the first fuel F1 supplied to the combustion chamber 4, increases at a greater rate after the time T1 has elapsed than before the time T1 has elapsed, as shown in Fig. 5C. Therefore, it is possible to gradually increase the turbine inlet temperature T1T and prevent the concentration of unburned fuel in the combustion gas from exceeding the predetermined concentration.

[0086] As another example of gradually increasing the turbine inlet temperature T1T, in the operating method for a gas turbine according to the first embodiment, the co-firing ratio control unit 110 controls each unit so that a reduction speed Sng of the flow rate of the second fuel F2 becomes a first reduction speed Sng1 before the time T1 has elapsed, and controls each unit so that the reduction speed Sng of the flow rate of the second fuel F2 becomes a second reduction speed Sng2 smaller than the first reduction speed Sng1 after the time T1 has elapsed.

[0087] As a result, the natural gas flow rate, which represents the amount of the second fuel F2 supplied to the combustion chamber 4, decreases at a lower rate after the time T1 has elapsed than before the time T1 has elapsed, as shown by the graphic line L7 in Fig. 5D. Therefore, it is possible to gradually increase the turbine inlet temperature T1T and prevent the concentration of unburned fuel in the combustion gas from exceeding the specified concentration.

[0088] In the operational method for the gas turbine according to the first embodiment, the second reduction speed Sng2, which is smaller than the first reduction speed Sng1, may also take a negative value, as in a period from time T1 to time T2 in Fig. 5D, and may also temporarily increase with the passage of time. However, even if the second reduction rate Sng2 becomes a negative value, it is desirable that at least the increase rate of the co-firing ratio becomes a positive value, and in the gas turbine operating method according to the first embodiment, it is desirable that the increase rate of the co-firing ratio maintains a constant value.

[0089] The control of changing the increase speed Sam of the flow rate of the first fuel F1 from the first increase speed Sam1 to the second increase speed Sam2 after the lapse of the time T1 and the control of changing the decrease speed Sng of the flow rate of the second fuel F2 from the first decrease speed Sng1 to the second decrease speed Sng2 after the lapse of the time T1 described above may be performed simultaneously, or only one of them may be performed.

[0090] When the rising rate Sam of the flow rate of the first fuel F1 and the falling rate Sng of the flow rate of the second fuel F2 are controlled, the rising rate of the co-firing ratio can be maintained at a certain constant rising rate.

[0091] That is, in step S10 of increasing the co-firing ratio, the control unit 110 of the control device 100 preferably controls the increasing speed Sam of the flow rate of the first fuel F1 to the first increasing speed Sam1 and sets the decreasing speed Sng of the flow rate of the second fuel F2 to the first decreasing speed Sng1 so that the turbine inlet temperature T1T becomes the first temperature while maintaining the change rate of the co-firing ratio at a first change rate when it is determined that the concentration of the unburned fuel does not exceed the certain concentration, based on the information on the relationship between the turbine inlet temperature T1T and the co-firing ratio as shown in the graph of Fig. 3. In step S10 of increasing the co-firing ratio, the control unit 110 of the co-firing ratio increasing control device 100 preferably sets the increasing rate Sam of the flow rate of the first fuel F1 to the second increasing rate Sam2, which is greater than the first increasing rate Sam1, and sets the decreasing rate Sng of the flow rate of the second fuel F2 to the second decreasing rate Sng2, which is smaller than the first decreasing rate Sng1, so that the turbine inlet temperature T1T becomes the second temperature higher than the above-described first temperature while maintaining the change rate of the co-firing ratio at the above-described first change rate, when it is determined that the concentration of the unburned fuel is about to exceed the certain concentration,based on the information described above.

[0092] With the operating method for a gas turbine according to the first embodiment, the concentration of the unburned fuel in the combustion gas can be prevented from exceeding the predetermined concentration without changing the rate of change of the co-firing ratio.

[0093] In the gas turbine operating method according to the first embodiment described above, the turbine inlet temperature T1T is gradually increased while increasing the co-firing ratio, with the co-firing ratio increase rate maintained at a certain constant rate. However, the turbine inlet temperature T1T may be gradually increased while increasing the co-firing ratio despite the variation in the co-firing ratio increase rate.

[0094] After step S10 of increasing the co-firing ratio is executed, the process proceeds to step S20, where the co-firing ratio control unit 110 determines whether the co-firing ratio has reached 100%. If the co-firing ratio control unit 110 determines that the co-firing ratio has not reached 100%, the process returns to step S10.

[0095] If the co-firing ratio control unit 110 determines that the co-firing ratio has reached 100%, the process in this program ends. (On the operating method for the gas turbine in the second embodiment)

[0096] In the operating method for the gas turbine according to the first embodiment described above, the increasing speed Sam of the flow rate of the first fuel F1 and the decreasing speed Sng of the flow rate of the second fuel F2 are changed to increase the turbine inlet temperature T1T.

[0097] In the operating method of the gas turbine according to the second embodiment, the opening degree of the inlet guide vanes 6 is reduced to increase the turbine inlet temperature T1T.

[0098] In the operating method of the gas turbine according to the second embodiment, in step S10 of increasing the co-firing ratio, the control unit 100 controls each unit so that the opening degree of the inlet guide vane 6 becomes a first opening degree so that the turbine inlet temperature T1T becomes the first temperature, for example, when it is determined that the concentration of the unburned fuel does not exceed the specified concentration as before the lapse of time T1, based on the information regarding the relationship between the turbine inlet temperature T1T and the co-firing ratio as shown in the graph of Fig. 3. That is, the control device 100 calculates the opening degree (first opening degree) of the inlet guide vane 6 so that the turbine inlet temperature T1T becomes the first temperature, and outputs a control signal to the actuator 6a so that the calculated opening degree (first opening degree) is achieved when it is determined that the unburned fuel concentration does not exceed the predetermined concentration.

[0099] In the operating method of the gas turbine according to the second embodiment, in the step S10 of increasing the co-firing ratio, the control device 100 controls each unit so that the opening degree of the inlet guide vane 6 becomes a second opening degree smaller than the first opening degree so that the turbine inlet temperature T1T becomes the second temperature higher than the first temperature, for example, when it is determined that the concentration of the unburned fuel is about to exceed the predetermined concentration after the lapse of time T1, based on the information described above.That is, the control device 100 calculates the opening degree (second opening degree) of the inlet guide vane 6 so that the turbine inlet temperature T1T becomes the second temperature, and outputs a control signal to the actuator 6a so that the calculated opening degree (second opening degree) is obtained when it is determined that the concentration of the unburned fuel is about to exceed the predetermined concentration.

[0100] With the operating method of the gas turbine according to the second embodiment, the concentration of the unburned fuel in the combustion gas can be prevented from exceeding the predetermined concentration by changing the opening degree of the inlet guide vane 6.

[0101] In the operating method for the gas turbine according to the second embodiment, as described in the above-described operating method for the gas turbine according to the first embodiment, the increasing speed Sam of the flow rate of the first fuel F1 and the decreasing speed Sng of the flow rate of the second fuel F2 may also be changed to increase the turbine inlet temperature T1T.

[0102] As a method for controlling the turbine inlet temperature T1T to the second temperature, it is also possible to reduce the amount of air flowing into the combustion chamber 4 by extracting air from the compressor 3. In this case, the extracted air can be discharged via an exhaust air line 13 provided in Fig. 1, for example, represented by a double-dashed chain line, can be used to cool the turbine 5, etc. In this way, the concentration of unburned fuel in the combustion gas can be prevented from exceeding the specified concentration.

[0103] In particular, the flow rate of the air flowing into the combustion chamber 4 can be changed by adjusting the degree of opening of an exhaust air flow control valve 27 which is arranged in the Fig. 1 and is configured to control, for example, the flow rate of the compressed air (exhaust air) flowing in the exhaust air line 13.

[0104] For example, in the operation method of the gas turbine according to the second embodiment, in step S10 of increasing the co-firing ratio, the control unit 100 controls each unit so that the opening degree of the exhaust air flow control valve 27 becomes a first opening degree so that the turbine inlet temperature T1T becomes the first temperature, for example, when it is determined that the concentration of the unburned fuel does not exceed the specified concentration as before the lapse of time T1, based on the information regarding the relationship between the turbine inlet temperature T1T and the co-firing ratio as shown in the graph of Fig. 3. That is, the control device 100 calculates the opening degree (first opening degree) of the exhaust air flow control valve 27 so that the turbine inlet temperature T1T becomes the first temperature, and outputs a control signal to an actuator (not shown) of the exhaust air flow control valve 27 so that the calculated opening degree (first opening degree) is obtained when it is determined that the concentration of the unburned fuel does not exceed the predetermined concentration.

[0105] In the operating method of the gas turbine according to the second embodiment, in the step S10 of increasing the co-firing ratio, the control device 100 controls each unit so that the opening degree of the exhaust air flow control valve 27 becomes a second opening degree larger than the first opening degree so that the turbine inlet temperature T1T becomes the second temperature higher than the first temperature, for example, when it is determined that the unburned fuel concentration is about to exceed the predetermined concentration after the lapse of time T1, based on the information described above.That is, the control device 100 calculates the opening degree (second opening degree) of the exhaust air flow control valve 27 such that the turbine inlet temperature T1T becomes the second temperature, and outputs a control signal to the actuator (not shown) of the exhaust air flow control valve 27 such that the calculated opening degree (second opening degree) is obtained when it is determined that the concentration of the unburned fuel is about to exceed the predetermined concentration.

[0106] The first opening degree and the second opening degree of the exhaust air flow control valve 27 are irrelevant to the first opening degree and the second opening degree of the intake guide vane 6 described above. The first opening degree of the exhaust air flow control valve 27 may also include a case where the exhaust air flow control valve 27 is completely closed.

[0107] With the operating method of the gas turbine according to the second embodiment, the concentration of the unburned fuel in the combustion gas can be prevented from exceeding the predetermined concentration by changing the opening degree of the exhaust air flow control valve 27. (Regarding the operating method for the gas turbine in the third embodiment)

[0108] In the operating methods for the gas turbine according to the first embodiment and the second embodiment described above, the increase in the amount of unburned fuel generated is reduced by increasing the turbine inlet temperature T1T.

[0109] In the operating method of the gas turbine according to the third embodiment, the increase in the amount of unburned fuel generated is reduced by reducing the increasing rate of the co-firing ratio.

[0110] Fig. 6A is a diagram showing a transition of the unburned fuel concentration, ie, an unburned ammonia concentration, during the execution of step S10 for increasing the co-firing ratio in the operating method of the gas turbine according to the third embodiment.

[0111] Fig. 6B is a diagram showing a transition of the co-firing ratio increasing rate during execution of step S10 of co-firing ratio increasing in the operation method of the gas turbine according to the third embodiment.

[0112] Fig. 6C is a diagram showing a transition of the co-firing ratio during execution of step S10 for increasing the co-firing ratio in the operating method of the gas turbine according to the third embodiment.

[0113] In an operating condition where the co-firing ratio is relatively high, the combustion of ammonia, which is the first fuel F1, tends to become unstable, and the unburned fuel of the first fuel F1 tends to be generated. In the operating condition where the co-firing ratio is relatively high, if the increasing rate of the co-firing ratio is relatively high, the combustion of ammonia, which is the first fuel F1, becomes more unstable, which may lead to an increase in the concentration of the unburned fuel of the first fuel F1 in the combustion gas. Therefore, in the operating condition where the co-firing ratio is relatively high, it is desirable to relatively decrease the increasing rate of the co-firing ratio.

[0114] Therefore, in the operation method of the gas turbine according to the third embodiment, in step S10 of increasing the co-firing ratio, the control unit 100 controls each unit so that the increasing rate of the co-firing ratio becomes a first increasing rate when, for example, it is determined that the concentration of the unburned fuel does not exceed the specified concentration as before the lapse of time T1, based on the information regarding the relationship between the turbine inlet temperature T1T and the co-firing ratio as shown in the graph of Fig. 3 shown.

[0115] In the operating method of the gas turbine according to the third embodiment, in step S10 of increasing the co-firing ratio, the control unit 100 controls each unit so that the increasing rate of the co-firing ratio becomes a second increasing rate lower than the first increasing rate when it is determined that the concentration of the unburned fuel is about to exceed the predetermined concentration based on the information described above.

[0116] That is, in the operating method of the gas turbine according to the third embodiment, the fuel flow rate calculation unit 111 of the control unit 100 calculates the flow rates of the first fuel F1 and the second fuel F2 supplied from the first fuel supply system 21 and the second fuel supply system 22 to the combustor 4 so that the increase rate of the co-firing ratio becomes the first increase rate while, for example, maintaining the turbine inlet temperature T1T at the temperature Ta when it is determined that the unburned fuel concentration does not exceed the predetermined concentration.Then, the valve control signal output unit 112 of the control device 100 outputs the control signals to the actuators (not shown) of the first fuel flow control valve 23 and the second fuel flow control valve 25, so that the first fuel F1 and the second fuel F2 are supplied to the combustion chamber 4 at the flow rates calculated by the fuel flow calculation unit 111.

[0117] For example, in the area where the co-firing ratio is smaller than the value M1 in Fig. 3 is, as before the expiration of time T1 in a diagram line L10 of Fig. 6B and a diagram line L11 of Fig. 6C, the co-firing ratio increases at a certain constant increase rate (first increase rate).

[0118] In the operating method of the gas turbine according to the third embodiment, when it is determined that the unburned fuel concentration is about to exceed the predetermined concentration, the fuel flow rate calculation unit 111 of the control unit 100 calculates the flow rates of the first fuel F1 and the second fuel F2 supplied from the first fuel supply system 21 and the second fuel supply system 22 to the combustor 4 so that the increase rate of the co-firing ratio becomes a second increase rate lower than the first increase rate while, for example, maintaining the turbine inlet temperature T1T at the temperature Ta.Then, the valve control signal output unit 112 of the control device 100 outputs the control signals to the actuators (not shown) of the first fuel flow control valve 23 and the second fuel flow control valve 25, so that the first fuel F1 and the second fuel F2 are supplied to the combustion chamber 4 at the flow rates calculated by the fuel flow calculation unit 111.

[0119] For example, in the area of Fig. 3, in which the co-firing ratio is greater than the value M1, as shown after the lapse of time T1 in the graphic line L10 of Fig. 6B and the graphic line L11 of Fig. 6C, the co-firing ratio increases with the increasing rate at which the increasing rate of the co-firing ratio is smaller than that before the lapse of time T1.

[0120] In the operating method for the gas turbine according to the third embodiment, for example, in the area in Fig. 3, in which the co-firing ratio is greater than the value M1, the graphic line L1 in the area right below of the graphic line L2, as shown by a dashed line in Fig. 3. Therefore, when the co-firing ratio becomes larger than the value M1, the concentration of unburned fuel (concentration of unburned ammonia) gradually increases, as shown after the elapse of time T1 in the graphic line L9 in Fig. 6A.

[0121] However, by reducing the increase rate of the co-firing ratio, the combustion of ammonia, the first fuel F1, is less likely to become unstable as described above, and thus it is possible to reduce the increase in the unburned fuel concentration compared to the case where the increase rate of the co-firing ratio is not reduced. Therefore, the unburned fuel concentration can be prevented from exceeding the predetermined concentration even when unburned fuel is generated.

[0122] In the operating method of the gas turbine according to the third embodiment, after the elapse of time T1, the increase rate of the co-firing ratio is set to be lower than that before the elapse of time T1. In this case, a lower limit value for the increase rate of the co-firing ratio may be set. That is, for example, as shown in Fig. 6B shows that after the elapse of time T1, the rate of increase of the co-firing ratio can be gradually reduced until a time T3 has elapsed. After the elapse of time T3, the co-firing ratio can be maintained at the time of elapse of time T3 until the elapse of time Te (ie, until the co-firing ratio reaches 100%).

[0123] Therefore, in the operation method of the gas turbine according to the third embodiment, in the step S10 of increasing the co-firing ratio, the control unit 100 may control each unit so that the increasing rate of the co-firing ratio becomes the second increasing rate which is lower than the first increasing rate and not lower than the predetermined lower limit value, when it is determined that the concentration of the unburned fuel is about to exceed the specified concentration, based on the information regarding the relationship between the turbine inlet temperature T1T and the co-firing ratio as shown in the graph of Fig. 3 shown.

[0124] This makes it possible to increase the co-firing ratio in a relatively short time while reducing the increase in the amount of unburned fuel produced.

[0125] The lower limit described above is preferably a positive value. This makes it possible to increase the co-firing ratio in a relatively short time while simultaneously reducing the increase in the amount of unburned fuel produced.

[0126] The lower limit described above can be a negative value. This means that the rate of increase in the co-firing ratio can be a negative value. Although it will take some time to bring the co-firing ratio closer to 100%, it is possible to further reduce the increase in the amount of unburned fuel generated.

[0127] As described above, the increase rate of the co-firing ratio can be made negative, that is, the increase rate of the supply amount of the first fuel F1 can be temporarily made larger than the increase rate of the supply amount of the second fuel F2. For example, in a case where it is difficult to reduce the emission of unburned fuel, the amount of unburned fuel generated can be reduced by operating the fuel system 20 to temporarily reduce the co-firing ratio. (Regarding the operating method for the gas turbine in the fourth embodiment)

[0128] In the above-described operating methods of the gas turbine according to the first embodiment to the third embodiment, in step S10 of increasing the co-firing ratio, the process is performed without using the concentration sensor 9 for detecting the ammonia concentration in the combustion gas.

[0129] In the operation method of the gas turbine according to the fourth embodiment, the process is performed using the concentration sensor 9 in step S10 to increase the co-firing ratio.

[0130] Specifically, in the operation method of the gas turbine according to the fourth embodiment, in step S10 of increasing the co-firing ratio, the control device 100 refers to a detected value of the ammonia concentration in the combustion gas by the concentration sensor 9 when the control device 100 determines that the concentration of the unburned fuel does not exceed the predetermined concentration and when the control device 100 determines that the concentration of the unburned fuel is about to exceed the predetermined concentration.

[0131] For example, if the concentration sensor 9 cannot detect ammonia, the control device 100 can determine that the concentration of the unburned fuel does not exceed the predetermined concentration. If the ammonia value detected by the concentration sensor 9 exceeds a predetermined threshold, the control device 100 can determine that the concentration of the unburned fuel is about to exceed the predetermined concentration.

[0132] Moreover, for example, in the control for changing the increasing speed Sam of the flow rate of the first fuel F1 or the control for changing the decreasing speed Sng of the flow rate of the second fuel F2 in the first embodiment described above, feedback control may be performed based on the ammonia value detected by the concentration sensor 9.

[0133] For example, when the opening degree of the inlet guide vane 6 is changed in the second embodiment described above, feedback control can be performed based on the ammonia value detected by the concentration sensor 9.

[0134] For example, in the third embodiment described above, when the rate of increase of the co-firing ratio is changed, feedback control may be performed based on the ammonia value detected by the concentration sensor 9.

[0135] As described above, in the operation method of the gas turbine according to the fourth embodiment, in step S10 of increasing the co-firing ratio, the control device 100 changes at least one of the turbine inlet temperature T1T and the change rate of the co-firing ratio when the control device 100 determines that the concentration has increased based on the unburned fuel concentration of the first fuel F1 in the combustion gas detected by the concentration sensor 9.

[0136] This makes it possible to reduce the increase in the amount of unburned fuel.

[0137] The present disclosure is not limited to the above-described embodiments, and also includes an embodiment obtained by modifying the above-described embodiments or an embodiment obtained by appropriately combining these embodiments.

[0138] By gradually increasing the co-firing ratio by increasing the first fuel F1 while simultaneously reducing the second fuel F2, a combustion field is created in which, at a given time, flame stabilization is only possible with the first fuel F1 (independent flame stabilization by the first fuel F1 is possible).

[0139] Therefore, the timing for starting the change of at least the turbine inlet temperature T1T or the rate of change of the co-firing ratio in the process of increasing the co-firing ratio can be after the time when flame stabilization is possible only with the first fuel F1, as described above. Since stable combustion is possible only with the first fuel F1, the possibility of misfire is low, and it is easy to make a change in conditions such as changing the turbine inlet temperature T1T or changing the rate of change of the co-firing ratio.

[0140] The content described in the above embodiments is to be understood, for example, as follows (1) An operating method of a gas turbine according to at least one embodiment of the present disclosure is an operating method of a gas turbine 2, comprising: a step S10 of increasing a co-firing ratio of first fuel F1, whose co-firing ratio is to be increased, and second fuel F2, which is different from the first fuel F1. The step S10 of increasing the co-firing ratio includes changing at least one of a turbine inlet temperature T1T and a change rate of the co-firing ratio based on information regarding a relationship between the turbine inlet temperature T1T and the co-firing ratio described above.

[0141] As a result of intensive investigations by the present inventors, it was found that when an increase in the amount of unburned fuel generated is expected when the co-firing ratio described above is increased, the increase in the amount of unburned fuel generated can be reduced by changing the turbine inlet temperature T1T or by changing the rate of change of the co-firing ratio described above.

[0142] According to the above method (1), it is possible to reduce the increase in the amount of unburned fuel produced.

[0143] (2) In some embodiments of the above method (1), the above-described information is preferably information regarding a relationship between the turbine inlet temperature T1T, the above-described co-firing ratio, and an unburned fuel concentration of the first fuel F1 in a combustion gas.

[0144] As a result of intensive investigations by the present inventors, it was found that the relationship between the turbine inlet temperature T1T and the co-firing ratio described above affects the concentration of the unburned fuel of the first fuel F1 in the combustion gas.

[0145] According to the above method (2), the increase in the amount of unburned fuel generated can be reduced by changing at least one of the turbine inlet temperature T1T and the change rate of the co-firing ratio described above based on the above-described information.

[0146] (3) In some embodiments of the above method (2), the step S10 of increasing the co-firing ratio preferably comprises changing the turbine inlet temperature T1T so that the concentration of unburned fuel in the combustion gas does not exceed a certain concentration based on the information described above.

[0147] According to the above method (3), by changing the turbine inlet temperature T1T, the concentration of unburned fuel in the combustion gas can be prevented from exceeding the predetermined concentration.

[0148] (4) In some embodiments of the method (3) above, the step S10 of increasing the co-firing ratio preferably includes controlling the turbine inlet temperature T1T such that the turbine inlet temperature T1T becomes a first temperature when it is determined that the unburned fuel concentration does not exceed the specified concentration based on the information described above. The step S10 of increasing the co-firing ratio preferably includes controlling the turbine inlet temperature T1T such that the turbine inlet temperature T1T becomes a second temperature higher than the first temperature when it is determined that the unburned fuel concentration is about to exceed the predetermined concentration based on the information described above.

[0149] According to the above method (4), by increasing the turbine inlet temperature T1T, the concentration of unburned fuel in the combustion gas can be prevented from exceeding the predetermined concentration.

[0150] (5) In some embodiments of the above method (4), the step S10 of increasing the co-firing ratio preferably includes setting an increasing speed Sam of a flow rate of the first fuel F1 to a first increasing speed Sam1 such that the turbine inlet temperature T1T becomes the first temperature when it is determined that the concentration of the unburned fuel does not exceed the specified concentration based on the information described above.The step S10 of increasing the co-firing ratio preferably includes setting the increasing rate Sam of the flow rate of the first fuel F1 to a second increasing rate Sam2 that is greater than the first increasing rate Sam1 so that the turbine inlet temperature T1T becomes the second temperature when it is determined that the concentration of the unburned fuel is about to exceed the specified concentration based on the information described above.

[0151] According to the above method (5), the concentration of the unburned fuel in the combustion gas can be prevented from exceeding the predetermined concentration by increasing the increasing speed Sam of the flow rate of the first fuel F1.

[0152] (6) In some embodiments of the above method (4) or (5), the step S10 of increasing the co-firing ratio preferably includes setting a reduction speed Sng of a flow rate of the second fuel F2 to a first reduction speed Sng1 such that the turbine inlet temperature T1T becomes the first temperature when it is determined that the concentration of the unburned fuel does not exceed the specified concentration based on the information described above.The step S10 of increasing the co-firing ratio preferably includes setting the reduction rate Sng of the flow rate of the second fuel F2 to a second reduction rate Sng2 that is smaller than the first reduction rate Sng1 so that the turbine inlet temperature T1T becomes the second temperature when it is determined that the concentration of the unburned fuel is about to exceed the specified concentration based on the information described above.

[0153] According to the above method (6), the concentration of the unburned fuel in the combustion gas can be prevented from exceeding the predetermined concentration by reducing the reducing speed Sng of the flow rate of the second fuel F2.

[0154] (7) In some embodiments, in the above method (4), the step S10 of increasing the co-firing ratio preferably includes setting an increasing rate Sam of a flow rate of the first fuel F1 to a first increasing rate Sam1 and setting a decreasing rate Sng of a flow rate of the second fuel F2 to a first decreasing rate Sng1 such that the turbine inlet temperature T1T becomes the first temperature while maintaining the change rate of the co-firing ratio at a first change rate when it is determined that the concentration of the unburned fuel does not exceed the specified concentration based on the information described above.The step S10 of increasing the co-firing ratio preferably includes setting the increasing rate Sam of the flow rate of the first fuel F1 to a second increasing rate Sam2 that is greater than the first increasing rate Sam1, and setting the decreasing rate Sng of the flow rate of the second fuel F2 to a second decreasing rate Sng2 that is smaller than the first decreasing rate Sng1, such that the turbine inlet temperature T1T becomes the second temperature while maintaining the changing rate of the co-firing ratio at the first changing rate when it is determined that the concentration of the unburned fuel is about to exceed the specified concentration based on the information described above.

[0155] According to the above method (7), the concentration of unburned fuel in the combustion gas can be prevented from exceeding the predetermined concentration without changing the rate of change of the co-firing ratio.

[0156] (8) In some embodiments of the above method (4), the gas turbine 2 includes a compressor (compressor 3) for supplying compressed air to a turbine 5 and an inlet guide vane 6 for controlling a flow rate of the air supplied to the compressor (compressor 3). The step S10 of increasing the co-firing ratio preferably includes setting an opening degree of the inlet guide vane 6 to a first opening degree such that the turbine inlet temperature T1T becomes the first temperature when it is determined that the unburned fuel concentration does not exceed the specified concentration based on the information described above.The step S10 of increasing the co-firing ratio preferably includes setting the opening degree of the inlet guide vane 6 to a second opening degree that is smaller than the first opening degree so that the turbine inlet temperature T1T becomes the second temperature when it is determined that the concentration of the unburned fuel is about to exceed the predetermined concentration based on the information described above.

[0157] According to the above method (8), by changing the opening degree of the inlet guide vane 6, the concentration of the unburned fuel in the combustion gas can be prevented from exceeding the predetermined concentration.

[0158] (9) In some embodiments of the above method (4), the gas turbine 2 includes a compressor (compressor 3) for supplying compressed air to a turbine 5, an exhaust air duct 13 for exhausting air from the compressor (compressor 3), and a control valve (exhaust air flow control valve 27) for controlling a flow rate of the compressed air flowing in the exhaust air duct 13. The step S10 of increasing the co-firing ratio preferably includes setting an opening degree of the control valve (exhaust air flow control valve 27) to a first opening degree such that the turbine inlet temperature T1T becomes the first temperature when it is determined that the unburned fuel concentration does not exceed the specified concentration based on the information described above.The step S10 of increasing the co-firing ratio preferably includes setting the opening degree of the valve (exhaust air flow control valve 27) to a second opening degree greater than the first opening degree so that the turbine inlet temperature T1T becomes the second temperature when it is determined that the concentration of the unburned fuel is about to exceed the specified concentration based on the information described above.

[0159] According to the above method (9), by changing the opening degree of the valve (exhaust air flow control valve 27), the concentration of unburned fuel in the combustion gas can be prevented from exceeding the predetermined concentration.

[0160] (10) In some embodiments, the step S10 of increasing the co-firing ratio in any one of the above methods (3) to (9) preferably comprises setting an increase rate of the co-firing ratio to a first increase rate when it is determined that the concentration of the unburned fuel does not exceed the predetermined concentration based on the information described above. The step S10 of increasing the co-firing ratio preferably comprises setting the increase rate of the co-firing ratio to a second increase rate that is lower than the first increase rate when it is determined that the concentration of the unburned fuel is about to exceed the predetermined concentration based on the information described above.

[0161] According to the above method (10), by reducing the increasing rate of the co-firing ratio when the unburned fuel concentration of the first fuel F1 in the combustion gas is expected to exceed the predetermined concentration, the increase in the unburned fuel concentration of the first fuel F1 in the combustion gas can be reduced compared to a case where the increasing rate of the co-firing ratio is not reduced.

[0162] (11) In some embodiments of the above method (10), the step S10 of increasing the co-firing ratio preferably comprises setting the rate of increase of the co-firing ratio to a second rate of increase that is smaller than the first rate of increase and not smaller than a predetermined lower limit value when it is determined that the concentration of the unburned fuel is about to exceed the predetermined concentration based on the information described above.

[0163] According to the above method (11), it is possible to increase the co-firing ratio in a relatively short time and at the same time reduce the increase in the amount of unburned fuel generated.

[0164] (12) In some embodiments of the above method (11), the step S10 of increasing the co-firing ratio preferably includes setting the increase rate of the co-firing ratio to a second increase rate that is smaller than the first increase rate and a positive value that is not smaller than the predetermined lower limit value when it is determined that the concentration of the unburned fuel is about to exceed the set concentration based on the information described above.

[0165] According to the above method (12), it is possible to increase the co-firing ratio in a relatively short time and at the same time reduce the increase in the amount of unburned fuel produced.

[0166] (13) In some embodiments of the above method (11), the step S10 of increasing the co-firing ratio preferably includes setting the increase rate of the co-firing ratio to a second increase rate that is smaller than the first increase rate and is a negative value not smaller than the predetermined lower limit value when it is determined that the concentration of the unburned fuel is about to exceed the set concentration based on the information described above.

[0167] According to the above method (13), it is possible to further reduce the increase in the amount of unburned fuel generated, although it takes some time to increase the co-firing ratio.

[0168] (14) In some embodiments, in any of the above methods (2) to (13), the above-described information may be a map representing the relationship between the turbine inlet temperature T1T, the co-firing ratio, and the unburned fuel concentration.

[0169] According to the above method (14), it is relatively easy to control the turbine inlet temperature T1T or the change rate of the co-firing ratio.

[0170] (15) In some embodiments of the above method (14), the step S10 of increasing the co-firing ratio preferably includes changing the turbine inlet temperature T1T so as not to enter a region where the concentration of the unburned fuel is relatively high, which is preset in the map described above.

[0171] According to the above method (15), it is possible to reduce the increase in the amount of unburned fuel produced.

[0172] (16) An operating method of a gas turbine according to at least one embodiment of the present disclosure is an operating method of a gas turbine 2, comprising: a step S10 of increasing a co-firing ratio of first fuel F1, whose co-firing ratio is to be increased, and second fuel F2 different from the first fuel F1. The gas turbine 2 includes a sensor (concentration sensor 9) for detecting unburned fuel of the first fuel F1 in a combustion gas. The step S10 of increasing the co-firing ratio includes changing at least one of a turbine inlet temperature T1T and a change rate of the co-firing ratio when it is determined that a concentration of the unburned fuel of the first fuel F1 in the combustion gas, which is detected by the above-described sensor (concentration sensor 9), has increased based on the concentration.

[0173] According to the above method (16), it is possible to reduce the increase in the amount of unburned fuel generated.

[0174] (17) A control unit 100 for a gas turbine according to at least one embodiment of the present disclosure is a control unit for a gas turbine 2, including: a co-firing ratio control unit 110 configured to increase a co-firing ratio of first fuel F1, whose co-firing ratio is to be increased, and second fuel F2 different from the first fuel F1. The co-firing ratio control unit 110 is configured to change at least one of a turbine inlet temperature T1T and a change rate of the co-firing ratio based on information regarding a relationship between the turbine inlet temperature T1T and the co-firing ratio when the above-described co-firing ratio is increased.

[0175] According to the above configuration (17), it is possible to reduce the increase in the amount of unburned fuel generated. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] WO 2022 / 149540A

[0003]

Claims

[1] Operating method for a gas turbine, comprising: a step of increasing the co-combustion ratio of the first fuel, the co-combustion ratio of which is to be increased, and the second fuel which is different from the first fuel, wherein the step of increasing the co-combustion ratio comprises changing at least one of a turbine inlet temperature and a rate of change of the co-combustion ratio based on information regarding a relationship between the turbine inlet temperature and the co-combustion ratio. [2] The operating method for the gas turbine according to claim 1, wherein the information is information concerning a relationship between the turbine inlet temperature, the co-combustion ratio, and an unburned fuel concentration of the first fuel in a combustion gas. [3] The operating method for the gas turbine according to claim 2, wherein the step of increasing the co-combustion ratio comprises changing the turbine inlet temperature so that the concentration of the unburned fuel in the combustion gas does not exceed a certain concentration based on the information. [4] The gas turbine operating method according to claim 3, wherein the step of increasing the co-combustion ratio comprises: Controlling the turbine inlet temperature such that the turbine inlet temperature becomes a first temperature when it is determined that the concentration of the unburned fuel does not exceed the determined concentration based on the information; and Controlling the turbine inlet temperature such that the turbine inlet temperature becomes a second temperature higher than the first temperature when it is determined that the concentration of the unburned fuel is about to exceed the determined concentration based on the information. [5] The gas turbine operating method according to claim 4, wherein the step of increasing the co-combustion ratio comprises: Setting an increase rate of a flow rate of the first fuel to a first increase rate such that the turbine inlet temperature becomes the first temperature when it is determined that the concentration of the unburned fuel does not exceed the determined concentration based on the information; and Setting the rate of increase of the flow rate of the first fuel to a second rate of increase that is greater than the first rate of increase so that the turbine inlet temperature becomes the second temperature when it is determined that the concentration of the unburned fuel is about to exceed the specified concentration based on the information. [6] The gas turbine operating method according to claim 4 or 5, wherein the step of increasing the co-combustion ratio comprises: Setting a reduction rate of a flow rate of the second fuel to a first reduction rate such that the turbine inlet temperature becomes the first temperature when it is determined that the concentration of the unburned fuel does not exceed the determined concentration based on the information; and Setting the reduction rate of the flow rate of the second fuel to a second reduction rate that is lower than the first reduction rate so that the turbine inlet temperature becomes the second temperature when it is determined that the concentration of the unburned fuel is about to exceed the specified concentration based on the information. [7] The gas turbine operating method according to claim 4, wherein the step of increasing the co-combustion ratio comprises: Setting an increase rate of a flow rate of the first fuel to a first increase rate and setting a decrease rate of a flow rate of the second fuel to a first decrease rate so that the turbine inlet temperature becomes the first temperature while maintaining the change rate of the co-combustion ratio at a first change rate when it is determined that the concentration of the unburned fuel does not exceed the determined concentration based on the information; and Setting the rate of increase of the flow rate of the first fuel to a second increase rate that is greater than the first increase rate, and setting the rate of decrease of the flow rate of the second fuel to a second decrease rate that is smaller than the first decrease rate, so that the turbine inlet temperature becomes the second temperature while maintaining the rate of change of the co-combustion ratio at the first change rate, when it is determined that the concentration of the unburned fuel is about to exceed the certain concentration based on the information. [8] Operating method for the gas turbine according to claim 4, wherein the gas turbine comprises a compressor for supplying compressed air to a turbine and an inlet guide vane for controlling a flow rate of the air supplied to the compressor, and wherein the step of increasing the co-combustion ratio comprises: Setting an opening degree of the inlet guide vane to a first opening degree such that the turbine inlet temperature becomes the first temperature when it is determined that the concentration of the unburned fuel does not exceed the determined concentration based on the information; and Setting the opening degree of the inlet guide vane to a second opening degree less than the first opening degree so that the turbine inlet temperature becomes the second temperature when it is determined that the concentration of the unburned fuel is about to exceed the certain concentration based on the information. [9] Operating method for the gas turbine according to claim 4, wherein the gas turbine comprises a compressor for supplying compressed air to a turbine, an exhaust air line for extracting air from the compressor, and a control valve for controlling a flow rate of the compressed air flowing in the exhaust air line, and wherein the step of increasing the co-combustion ratio comprises: Setting an opening degree of the control valve to a first opening degree such that the turbine inlet temperature becomes the first temperature when it is determined that the concentration of the unburned fuel does not exceed the determined concentration based on the information; and Setting the opening degree of the control valve to a second opening degree greater than the first opening degree so that the turbine inlet temperature becomes the second temperature when it is determined that the concentration of the unburned fuel is about to exceed the certain concentration based on the information. [10] An operating method for the gas turbine according to any one of claims 3 to 9, wherein the step of increasing the co-combustion ratio comprises: Setting an increase rate of the co-combustion ratio to a first increase rate when it is determined that the concentration of the unburned fuel does not exceed the predetermined concentration based on the information; and Setting the co-combustion ratio increase rate to a second increase rate lower than the first increase rate when it is determined that the unburned fuel concentration is about to exceed the determined concentration based on the information. [11] The operating method for the gas turbine according to claim 10, wherein the step of increasing the co-combustion ratio comprises setting the rate of increase of the co-combustion ratio to a second rate of increase which is lower than the first rate of increase and not lower than a predetermined lower limit value when it is determined that the concentration of the unburned fuel is about to exceed the determined concentration based on the information. [12] The operating method for the gas turbine according to claim 11, wherein the step of increasing the co-combustion ratio comprises setting the rate of increase of the co-combustion ratio to a second rate of increase which is smaller than the first rate of increase and is a positive value not smaller than the predetermined lower limit value when it is determined that the concentration of the unburned fuel is about to exceed the certain concentration based on the information. [13] The operating method for the gas turbine according to claim 11, wherein the step of increasing the co-combustion ratio comprises setting the rate of increase of the co-combustion ratio to a second rate of increase which is smaller than the first rate of increase and is a negative value not smaller than the predetermined lower limit value when it is determined that the concentration of the unburned fuel is about to exceed the determined concentration based on the information. [14] The operating method for the gas turbine according to any one of claims 2 to 13, wherein the information is a map representing the relationship between the turbine inlet temperature, the co-combustion ratio and the unburned fuel concentration. [15] The operating method for the gas turbine according to claim 14, wherein the step of increasing the co-combustion ratio comprises changing the turbine inlet temperature so as not to enter a region where the concentration of the unburned fuel is relatively high, which is preset in the map. [16] Operating method for a gas turbine, comprising: a step of increasing the co-combustion ratio of the first fuel, the co-combustion ratio of which is to be increased, and the second fuel which is different from the first fuel, wherein the gas turbine comprises a sensor for detecting unburned fuel of the first fuel in a combustion gas, and wherein the step of increasing the co-combustion ratio comprises changing at least one of a turbine inlet temperature and a rate of change of the co-combustion ratio when it is determined that a concentration of the unburned fuel of the first fuel in the combustion gas detected by the sensor has increased based on the concentration. [17] Control device for a gas turbine, comprising: a co-combustion ratio control unit configured to increase a co-combustion ratio of first fuel, the co-combustion ratio of which is to be increased, and second fuel different from the first fuel, wherein the co-combustion ratio control unit is configured to change at least one of a turbine inlet temperature and a change rate of the co-combustion ratio based on information regarding a relationship between the turbine inlet temperature and the co-combustion ratio when the co-combustion ratio is increased.

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