Operating methods for gas turbine plants and control devices for gas turbine plants

Abstract

To improve the reliability of purging residual oil. [Solution] The method for operating a gas turbine plant comprises a gas turbine having a combustor equipped with nozzles for injecting fuel gas and fuel oil, a fuel gas system for supplying fuel gas to the nozzles, and a fuel oil system for supplying fuel oil to the nozzles. The method for operating a plant includes, when switching from a state in which the gas turbine is operated by supplying fuel oil from the fuel oil system to the nozzles (oil-fired) to a state in which the gas turbine is operated by supplying fuel gas from the fuel gas system to the nozzles (gas-fired), the first process of stopping the supply of fuel oil from the fuel oil system to the nozzles and then discharging the fuel oil remaining in the nozzles, and when combustion in the combustor is stopped from oil-fired, and when combustion in the combustor is stopped from gas-fired and the first process was not completed normally during the previous switchover, the second process of discharging the fuel oil remaining in the nozzles.

Description

Technical Field

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

Background Art

[0002] Patent Document 1 describes a gas turbine fuel oil purge system that reduces the amount of residual oil remaining in a pipe and discharged into a combustor when switching the fuel from oil to gas during operation. In the system described in Patent Document 1, the purge of residual oil is performed during continuous operation in which fuel gas is supplied and the gas is burning in the combustor.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the system described in Patent Document 1, since it is premised that the purge of residual oil is performed during continuous operation of the gas turbine, there is a problem that, for example, when the operation stops due to a trip or the like during the execution of the purge of residual oil, the purge of residual oil may not be performed properly.

[0005] The present disclosure has been made to solve the above problems, and an object thereof is to provide an operating method of a gas turbine plant and a control device for a gas turbine plant that can improve the certainty of purging residual oil.

Means for Solving the Problems

[0006] To solve the above problems, the method for operating a gas turbine plant according to the present disclosure is a method for operating a gas turbine plant comprising: a gas turbine having a combustor equipped with nozzles for injecting fuel gas and fuel oil; a fuel gas system for supplying the fuel gas to the nozzles; and a fuel oil system for supplying the fuel oil to the nozzles, wherein when switching from a state in which the gas turbine is operated by supplying the fuel oil from the fuel oil system to the nozzles to operate the gas turbine to a state in which the fuel gas is supplied from the fuel gas system to the nozzles to operate the gas turbine, the first process involves stopping the supply of the fuel oil from the fuel oil system to the nozzles and then discharging the fuel oil remaining in the nozzles; and a second process involves discharging the fuel oil remaining in the nozzles when combustion in the combustor is stopped from a state in which the gas turbine is operated by supplying the fuel oil from the fuel oil system to the nozzles, and when combustion in the combustor is stopped from a state in which the gas turbine is operated by supplying the fuel gas from the fuel gas system to the nozzles, and the first process was not completed normally during the preceding switchover.

[0007] The control device for a gas turbine plant according to this disclosure comprises a gas turbine having a combustor equipped with nozzles for injecting fuel gas and fuel oil, a fuel gas system for supplying the fuel gas to the nozzles, and a fuel oil system for supplying the fuel oil to the nozzles, and further comprises a first control unit that, when switching from a state in which the gas turbine is operated by supplying the fuel oil from the fuel oil system to the nozzles to operate the gas turbine to a state in which the fuel gas is supplied from the fuel gas system to the nozzles to operate the gas turbine, stops the supply of the fuel oil from the fuel oil system to the nozzles and then discharges the fuel oil remaining in the nozzles; and a second control unit that, when combustion in the combustor is stopped from a state in which the gas turbine is operated by supplying the fuel oil from the fuel oil system to the nozzles, and when combustion in the combustor is stopped from a state in which the gas turbine is operated by supplying the fuel gas from the fuel gas system to the nozzles, and the first process was not completed normally during the preceding switchover, discharges the fuel oil remaining in the nozzles. [Effects of the Invention]

[0008] According to the gas turbine plant operating method and gas turbine plant control device of this disclosure, the reliability of purging residual oil can be improved. [Brief explanation of the drawing]

[0009] [Figure 1] This is a block diagram showing an example configuration of a gas turbine power plant according to the present disclosure. [Figure 2] This is a schematic diagram of a nozzle according to an embodiment of the present disclosure. [Figure 3] This flowchart shows an example of the operation of a control device when switching from fuel oil to fuel gas according to the embodiment of this disclosure. [Figure 4] This is a schematic diagram illustrating the content of the first process according to the embodiment of this disclosure. [Figure 5]This flowchart shows an example of the operation of a control device during gas turbine fire extinguishing according to the present disclosure. [Figure 6] This is a schematic diagram illustrating the content of the second process according to the embodiment of this disclosure. [Figure 7] This is a timing chart showing an example of operation of a gas turbine power plant according to the embodiment of this disclosure. [Figure 8] This is a timing chart showing an example of operation of a gas turbine power plant according to the embodiment of this disclosure. [Figure 9] This is a timing chart showing an example of operation of a gas turbine power plant according to the embodiment of this disclosure. [Figure 10] This is a schematic block diagram showing the configuration of a computer according to the embodiments of this disclosure. [Modes for carrying out the invention]

[0010] Hereinafter, the operating method and control device of the gas turbine plant according to the embodiments of this disclosure will be described with reference to Figures 1 to 10. In each figure, the same or corresponding components are given the same reference numerals, and their descriptions will be omitted as appropriate.

[0011] (Example of a gas turbine power plant configuration) Figure 1 is a block diagram showing an example configuration of a gas turbine power plant 1 according to one embodiment of the present disclosure. The gas turbine power plant 1 comprises a control device 2, a fuel gas supply device 3, a fuel oil supply device 4, a purge fluid supply device 5, a fuel oil recovery device 6, a gas turbine 10, a generator 15, flow control valves 32, 42 and 52, and a shut-off valve 62. In Figure 1, the solid connecting lines indicate the piping routes through which fuel gas, fuel oil, or purge fluid flows. Note that the wiring routes through which electrical signals are transmitted and received between each valve 32, 42, 62 and 52 and the control device 2 are not shown. The gas turbine power plant 1 also comprises multiple sensors such as multiple flow sensors, pressure sensors, and temperature sensors, as well as multiple valves not shown. Furthermore, the gas turbine power plant 1 is an example configuration of the "gas turbine plant" of the present disclosure.

[0012] The gas turbine 10 comprises an air compressor 11, multiple combustors 12, a turbine 13, a rotor 14, and a generator 15. The air compressor 11 draws in air from the outside and compresses it, as shown by the dashed arrow, due to the rotation of the rotor 14 which passes through the air compressor 11 and the turbine 13, and the compressed air is discharged into the combustor 12.

[0013] Each combustor 12 comprises a combustor chamber 18 into which air flowing out from the air compressor 11 flows, and a combustor inner cylinder 19 into which air flowing out from the combustor chamber 18 flows. The combustor inner cylinder 19 is equipped with a nozzle 60 inside, as shown in Figure 2. The nozzle 60 has a longitudinal shape, and Figure 2 is a schematic diagram showing a cross-section of the nozzle 60 when it is cut by a plane parallel to the longitudinal direction and containing the central axis.

[0014] The nozzle 60 has injection holes 61-1 and 61-2 for fuel gas and injection holes 62-1 and 62-2 for fuel oil. The pipe 43 constituting the fuel supply path for the fuel oil reaches the injection holes 61-1 and 61-2. The pipe 33 constituting the fuel supply path for the fuel gas reaches the injection holes 62-1 and 62-2. Note that FIG. 2 is a schematic diagram, and in reality, the injection holes for injecting fuel gas are not limited to the two injection holes 61-1 and 61-2, and there are a plurality of them. The injection holes for injecting fuel oil are also not limited to the two injection holes 62-1 and 62-2, and there are a plurality of them. However, here, as the injection holes for fuel gas, at least two injection holes 61-1 and 61-2 are described, and as the injection holes for fuel oil, at least two injection holes 62-1 and 62-2 are described. Note that the nozzle 60 includes a plurality of types of nozzles such as a pilot nozzle and a main nozzle, for example. For simplicity of explanation, in this embodiment, it is regarded as one type of nozzle. In the example shown in FIG. 2, the right end portion facing the figure is the tip 60T of the nozzle 60.

[0015] The fuel gas supply device 3 stores fuel gas such as natural gas, for example, and supplies the fuel gas to the nozzle 60 via the flow rate regulating valve 32. The fuel oil supply device 4 stores fuel oil such as heavy oil, for example, and supplies the fuel oil to the nozzle 60 via the flow rate regulating valve 42.

[0016] The flow rate regulating valve 32 is connected at one end to the fuel gas supply device 3 via the pipe 31 (or tube 31), and at the other end to the pipe 33 connected to the nozzle 60. The fuel gas supply device 3, the pipe 31, the flow rate regulating valve 32, and the pipe 33 constitute a fuel gas system 30 that supplies fuel gas to the nozzle 60. The flow rate regulating valve 41 is electrically connected to the control device 2, and when receiving a valve opening command signal from the control device 2, it opens and closes the valve so as to be at the valve opening indicated by the received valve opening command signal to adjust the flow rate of the fuel gas.

[0017] The flow rate control valve 42 is connected at one end to the fuel oil supply device 4 via the pipe 41, and at the other end to the pipe 43 connected to the nozzle 60. The fuel oil supply device 4, the pipe 41, the flow rate control valve 42, and the pipe 43 constitute a fuel oil system 40 for supplying fuel oil to the nozzle 60. The flow rate control valve 42 is electrically connected to the control device 2, and when it receives a valve opening degree command signal from the control device 2, it opens and closes the valve so as to reach the valve opening degree indicated by the received valve opening degree command signal, thereby adjusting the flow rate of the fuel oil.

[0018] The purge fluid supply device 5 stores a purge fluid, which is a fluid used to discharge (purge) the fuel oil remaining in a part of the nozzle 60 and the fuel oil system 40. The purge fluid is discharged (sprayed) to a part of the nozzle 60 and the fuel oil system 40 via the flow rate control valve 52. The purge fluid is, for example, water or air, or both water and air. When the purge fluid is both water and air, the flow rate control valve 52 and the like are provided separately for a plurality of systems including the water system and the air system.

[0019] The flow rate control valve 52 is connected at one end to the purge fluid supply device 5 via the pipe 51, and at the other end to the pipe 53 connected to the pipe 43. The flow rate control valve 52 is electrically connected to the control device 2, and when it receives a valve opening degree command signal from the control device 2, it opens and closes the valve so as to reach the valve opening degree indicated by the received valve opening degree command signal, thereby adjusting the flow rate of the purge fluid.

[0020] The fuel oil recovery device 6 is a device for recovering the fuel oil discharged from a part of the nozzle 60 and the fuel oil system 40, and includes, for example, an oil drain tank. The fuel oil recovery device 6 recovers the fuel oil discharged from a part of the nozzle 60 and the fuel oil system 40 via a shut-off valve (or drain valve) 62.

[0021] The shut-off valve 62 is connected at one end to the fuel oil recovery device 6 via the pipe 61, and at the other end to the pipe 63 connected to the pipe 43. The shut-off valve 62 is electrically connected to the control device 2, and when it receives a valve opening / closing command signal from the control device 2, it operates to the open state or the closed state indicated by the received valve opening / closing command signal.

[0022] As shown in Figure 1, the combustion gas generated in the combustor cylinder 19 by the combustion of fuel gas or fuel oil flows out through an opening provided at the bottom of the combustor cylinder 19, as indicated by the dashed arrow. This flowing combustion gas enters the turbine 13, causing the rotor 14 to rotate, and the rotation of the rotor 14 generates electricity in the generator 15.

[0023] The control device 2 can be configured using, for example, a computer such as a server, personal computer, or microcomputer, and peripheral devices for that computer. The control device 2 is a functional block composed of a combination of hardware such as the computer and software such as a program executed by the computer, and includes a first control unit 21, a second control unit 22, and a storage unit 23, as shown in Figure 1. The storage unit 23 stores a flag F, which will be described later.

[0024] The first control unit 21 controls the fuel supplied to the combustor 12, switching from fuel gas to fuel oil, or from fuel oil to fuel gas, while the gas turbine 10 continues to operate. Generally, the main fuel supplied to the combustor 12 is fuel gas, and fuel oil is positioned as a backup fuel used in case of any problems with the supply of fuel gas or the combustion of fuel gas. Therefore, control is performed to switch from fuel gas to fuel oil, and then, once the problem with the fuel gas is resolved, control is performed to switch from fuel oil to fuel gas.

[0025] The first control unit 21, when switching from fuel gas to fuel oil and when switching from fuel oil to fuel gas, maintains a constant calorific value of the fuel supplied to the combustor 12, and performs a stepwise switch by proportionally distributing the calories between the fuel gas and fuel oil. For example, when switching from fuel oil to fuel gas, the first control unit 21 gradually switches the ratio of calories from fuel gas to fuel oil from 0:100 to 30:70, 50:50, 70:30, and 0:100.

[0026] Furthermore, when the first control unit 21 switches from a state in which the gas turbine 10 is operated by supplying fuel oil from the fuel oil system 40 to the nozzle 60 to operate the gas turbine 10 by supplying fuel gas from the fuel gas system 30 to the nozzle 60, it stops supplying fuel oil from the fuel oil system 40 to the nozzle 60 and then performs a first process to discharge the fuel oil remaining in the nozzle 60 and part of the fuel oil system 40.In the following, the state in which the gas turbine 10 is operated using only fuel oil as fuel will be referred to as oil-fired, and the state in which the gas turbine 10 is operated using only fuel gas will be referred to as gas-fired.In addition, the state in which the gas turbine 10 is operated using both fuel oil and fuel gas will be referred to as co-firing.

[0027] Here, an example of the operation of the first control unit 21 will be described with reference to Figure 3. Figure 3 is a flowchart showing an example of the operation of the control device 2 (first control unit 21) when switching from fuel oil to fuel gas. The process shown in Figure 3 is executed repeatedly at a predetermined cycle. When the process shown in Figure 3 starts, the first control unit 21 determines whether or not there has been an instruction to switch from oil-fired to gas-fired (step S1). The instruction to switch from oil-fired to gas-fired is issued, for example, manually or from another control device not shown. If there is no instruction to switch from oil-fired to gas-fired (step S1: NO), the first control unit 21 terminates the process shown in Figure 3.

[0028] When an instruction is given to switch from oil-fired to gas-fired operation (Step S1: YES), the first control unit 21 starts the switching process (Step S2). The switching process started in Step S2 is a process that switches the operating state from oil-fired to gas-fired by controlling the flow control valve 32 and the flow control valve 42, etc., thereby gradually changing the fuel distribution as described above.

[0029] Next, the first control unit 21 turns ON the flag F stored in the memory unit 23 (step S3). Flag F is a flag that is turned ON when switching from oil-fired to gas-fired operation and turned OFF when the first process, which will be described later, is completed successfully. As will be described later, the second control unit 22 determines that the first process was not completed successfully if this flag F is not OFF. Note that the ON and OFF of flag F may be determined, for example, by setting a 1-bit flag F to "1" and "0" and turning it OFF, or by setting it to "0" and turning it OFF and turning it to "1".

[0030] Next, the first control unit 21 determines whether or not the supply of fuel oil from the fuel oil system 40 to the nozzle 60 has stopped (step S4). The first control unit 21 repeatedly performs the determination process in step S4 until the supply of fuel oil stops (repeating from step S4: NO to step S4), and if the supply of fuel oil stops (step S4: YES), it starts the first process (step S5).

[0031] In this embodiment, the first process, as described above, is a process of stopping the supply of fuel oil from the fuel oil system 40 to the nozzle 60 when switching from oil-fired to gas-fired combustion, and then discharging the fuel oil remaining in the nozzle 60 and a portion of the fuel oil system 40. The first process is a purging process of residual oil while the gas turbine 10 is operating, and can be carried out as shown in Figure 4, for example. In the example of the first process shown in Figure 4, by closing the flow control valve 42 and the shut-off valve 62, and opening the flow control valve 52 (adjusting the valve opening), the purge fluid is injected from the piping 53 to the nozzle 60 as shown by the dashed arrow, thereby discharging the fuel oil remaining in the nozzle 60 and a portion of the piping 43 into the combustor 12.

[0032] After step S5, the first control unit 21 determines whether the first process was completed successfully (step S6). For example, in the first process, the first control unit 21 controls the flow control valve 42, flow control valve 52, shut-off valve 62, etc., using sequence control, and if all stages of control are performed according to predetermined procedures, then in step S6, the first control unit 21 determines that the first process was not completed successfully (the first process terminated abnormally) if, in the sequence control, any stage of control is skipped when the first process ends, or if the operation of the gas turbine 10 stops before the completion of the first process.

[0033] If the first process is completed successfully (step S6: YES), the first control unit 21 turns off flag F (step S7) and terminates the process shown in Figure 3. If the first process is not completed successfully (step S6: NO), the first control unit 21 determines whether the first process terminated abnormally (step S8). If the first process terminated abnormally (step S8: YES), the first control unit 21 terminates the process shown in Figure 3 without turning off flag F (without performing the process in step S7). If the first process has not terminated abnormally (i.e., is in progress) (step S8: NO), the first control unit 21 performs the determination process in step S6.

[0034] The process shown in Figure 3 terminates with flag F OFF if the first process completes successfully, and terminates with flag F ON if the first process does not complete successfully.

[0035] Furthermore, the second control unit 22 shown in Figure 1 performs processing when the gas turbine 10 is shut down. When the combustion in the combustor 12 is stopped from a state in which the gas turbine 10 is operated by supplying fuel oil from the fuel oil system 40 to the nozzle 60 (oil-fired), or when the combustion in the combustor 12 is stopped from a state in which the gas turbine 10 is operated by supplying fuel gas from the fuel gas system 30 to the nozzle 60 (gas-fired), and the first processing was not completed normally when the previous switch from oil-fired to gas-fired was made, the second control unit 22 performs a second processing to discharge the fuel oil remaining in the nozzle 60.

[0036] Here, an example of the operation of the second control unit 22 will be described with reference to Figure 5. Figure 5 is a flowchart showing an example of the operation of the control device 2 (second control unit 22) when the gas turbine 10 is extinguished. The process shown in Figure 5 is executed repeatedly at a predetermined cycle. When the process shown in Figure 5 is started, the second control unit 22 determines whether or not there has been an instruction to extinguish the gas turbine 10 (step S11). An instruction to extinguish the gas turbine 10 is an instruction to stop combustion in the combustor 12, such as an instruction to trip the gas turbine 10 or an instruction to stop the operation of the gas turbine 10. An instruction to extinguish the gas turbine 10 is issued, for example, manually or from another control device not shown. If there is no instruction to extinguish the gas turbine 10 (step S11: NO), the second control unit 22 terminates the process shown in Figure 3.

[0037] If a fire extinguishing instruction is given for the gas turbine 10 (step S11: YES), the second control unit 22 starts the fire extinguishing process (step S12). The fire extinguishing process in step S12 is a process to stop combustion in the combustor 12 and is carried out according to a predetermined procedure depending on the content (type) of the fire extinguishing instruction. Next, the second control unit 22 determines whether or not the fire extinguishing process is complete (i.e., whether or not combustion in the combustor 12 has stopped) (step S13). The second control unit 22 repeatedly performs the determination process in step S13 until the fire extinguishing process is complete (repeating from step S13: NO to step S13), and if the fire extinguishing process is complete (step S13: YES), it determines whether or not it was an oil-fired fire extinguishing (step S14).

[0038] If the fire was not extinguished using oil (i.e., it was extinguished using gas) (Step S14: NO), the second control unit 22 determines whether flag F is ON or OFF (Step S15). If the flag is not ON (i.e., the preceding first process was completed successfully and flag F was OFF) (Step S15), the second control unit 22 terminates the process shown in Figure 5.

[0039] On the other hand, if the fire was extinguished using oil (step S14: YES), and if flag F is ON (step S15: YES), the second control unit 22 starts the second process (step S16).

[0040] In this embodiment, the second process is, as described above, a process for discharging fuel oil remaining in the nozzle 60 when combustion in the combustor 12 is stopped from oil-fired combustion, or when combustion in the combustor 12 is stopped from gas-fired combustion and the first process was not completed normally during the preceding switch from oil-fired combustion to gas-fired combustion. The second process is a purging process for residual oil when the gas turbine 10 has been extinguished (preferably a purging process for residual oil performed immediately after extinguishing combustion when there is residual pressure in the casing (at least higher than atmospheric pressure)), and can be carried out as shown in Figure 6, for example. In the example of the second process shown in Figure 6, by closing the flow control valve 42 and the flow control valve 52 and opening the shut-off valve 62, the fuel oil remaining in the nozzle 60 is returned to the piping 43 using the residual pressure in the casing, as shown by the dashed arrows, and further recovered to the fuel oil recovery device 6 via the shut-off valve 62. Also, in the example of the second process shown in Figure 6, the fuel oil remaining in the piping 43 is recovered to the fuel oil recovery device 6 via the shut-off valve 62. In the second treatment, after the treatment shown in Figure 6, any remaining fuel oil may be discharged into the combustor 12 using a purge fluid, similar to the example of the first treatment shown in Figure 4.

[0041] After step S16, the second control unit 22 determines whether the second process is complete (step S17). In step S17, the second control unit 22 determines that the second process is complete if, for example, the second process is performed by sequence control and all stages of control are executed in a predetermined procedure. Next, the second control unit 22 repeatedly performs the determination process in step S17 until the second process is complete (repeating from step S17: NO to step S17), and if the second process is complete (step S17: YES), it turns off flag F (step S18) and terminates the process shown in Figure 5.

[0042] In the process shown in Figure 5, if the gas turbine 10 is extinguished while oil-fired or with flag F ON, the second process is executed. If the gas turbine 10 is extinguished while gas-fired and with flag F OFF, the second process is not executed.

[0043] Next, we will explain an example of the operation of the gas turbine power plant 1 with reference to the timing charts shown in Figures 7 to 9. Figures 7 to 9 schematically show, from top to bottom, the content of the control instruction (timing of instruction issuance), the operating status of the gas turbine, the amount of fuel gas supplied, the amount of fuel oil supplied, whether or not residual oil discharge treatment was performed, and the state of flag F, with the horizontal axis being the time axis. Note that the time axis is not equiscaled. Figure 7 shows an example where the gas turbine 10 is extinguished in gas-fired mode after the first treatment performed during the switch from oil-fired to gas-fired mode has been completed successfully. Figure 8 shows an example where the gas turbine 10 is extinguished in gas-fired mode after the first treatment performed during the switch from oil-fired to gas-fired mode has not been completed successfully (after the first treatment has failed). Figure 9 shows an example where the gas turbine 10 is extinguished in oil-fired mode.

[0044] In the example shown in Figure 7, the turbine is in oil-fired mode, and at time t11, an instruction to switch from oil-fired to gas-fired mode is issued. From time t11 to time t12 (just before), co-firing occurs, with the fuel oil supply gradually decreasing and the fuel gas supply gradually increasing. At time t12, gas-fired mode is activated, and the fuel oil supply is stopped. The first process starts at time t12 and is completed successfully at time t13. Flag F changes from OFF to ON at time t11 and turns OFF at time t13. Also, at time t14, an instruction to extinguish the gas turbine 10 is issued, and the fire is extinguished at time t15. In this example, the second process is not executed when the fire is extinguished from gas-fired mode.

[0045] In the example shown in Figure 8, the turbine is in an oil-fired state, and at time t21, an instruction to switch from oil-fired to gas-fired is issued. From time t21 to time t22 (just before), co-firing occurs, with the fuel oil supply gradually decreasing and the fuel gas supply gradually increasing. At time t22, it switches to gas-fired, and the fuel oil supply stops. Also, at time t24, an instruction to extinguish the gas turbine 10 is issued, and the fire is extinguished at time t25. The second process starts at time t25 and is completed at time t26. Flag F changes from OFF to ON at time t21 and turns OFF at time t26. In this example, the second process is executed when the fire is extinguished from gas-fired operation.

[0046] In the example shown in Figure 9, under oil-fired conditions, a fire extinguishing instruction for gas turbine 10 is issued at time t31, and the fire is extinguished at time t32. The second process starts at time t32 and is completed at time t33. In the case of fire extinguishing from an oil-fired state, the second process is executed regardless of the state of flag F.

[0047] (Effects and Benefits) In the operation method and control device 2 for the gas turbine power plant 1 (gas turbine plant) with the above configuration, a first process and a second process are performed in the gas turbine power plant 1 which includes a gas turbine 10 having a combustor 12 equipped with nozzles 60 for injecting fuel gas and fuel oil, a fuel gas system 30 for supplying fuel gas to the nozzles 60, and a fuel oil system 40 for supplying fuel oil to the nozzles 60. In the first process, when switching from a state in which the gas turbine 10 is operated by supplying fuel oil from the fuel oil system 40 to the nozzles 60 to operate the gas turbine, the supply of fuel oil from the fuel oil system 40 to the nozzles 60 is stopped, and then the fuel oil remaining in the nozzles 60 is discharged. Furthermore, the second process discharges any remaining fuel oil from the nozzle 60 when combustion in the combustor 12 is stopped after fuel oil has been supplied from the fuel oil system 40 to the nozzle 60 to operate the gas turbine 10, or when combustion in the combustor 12 is stopped after fuel gas has been supplied from the fuel gas system 30 to the nozzle 60 to operate the gas turbine 10, and the first process was not completed successfully during the preceding switch from oil-fired to gas-fired operation. With this configuration, if the first process performed during the switch from oil-fired to gas-fired operation fails, the second process is executed after the gas-fired operation is extinguished, thereby improving the reliability of purging residual oil.

[0048] Furthermore, in this embodiment, flag F, which is turned ON when switching from oil-fired to gas-fired operation and OFF when the first process is successfully completed, is not OFF when it is determined that the first process was not successfully completed. This configuration simplifies the determination process and reduces the amount of information needed to store the failure. The ON and OFF states of flag F may be interpreted interchangeably.

[0049] Furthermore, in this embodiment, flag F is turned ON automatically or manually after the start of the switch from oil-fired to gas-fired operation. This configuration allows for more flexible activation of flag F compared to the case where it is only activated automatically.

[0050] Furthermore, the second process includes a procedure to discharge the fuel oil remaining in the nozzle 60 from the tip 60T of the nozzle 60 toward the fuel oil system 40, utilizing the residual pressure of the combustor chamber 18 (chamber) of the gas turbine 10. With this configuration, residual oil can be discharged efficiently.

[0051] (Other embodiments) Although embodiments of this disclosure have been described in detail above with reference to the drawings, the specific configuration is not limited to these embodiments and may include design changes, etc., that do not depart from the gist of this disclosure. For example, in the above embodiments, the first process and the second process are different processes, but the first process and the second process may be the same process.

[0052] (Computer configuration) Figure 10 is a schematic block diagram showing the configuration of a computer according to at least one embodiment. The computer 90 includes a processor 91, main memory 92, storage 93, and an interface 94. The control device 2 described above is implemented in the computer 90. The operation of each processing unit described above is stored in storage 93 in the form of a program. The processor 91 reads the program from storage 93, loads it into main memory 92, and executes the above processing according to the program. The processor 91 also allocates memory areas in main memory 92 corresponding to each of the above-described storage units according to the program.

[0053] The program may be for implementing some of the functions that the computer 90 is to perform. For example, the program may perform functions in combination with other programs already stored in storage, or in combination with other programs implemented in other devices. In other embodiments, the computer may include a custom LSI (Large Scale Integrated Circuit) such as a PLD (Programmable Logic Device) in addition to, or instead of, the above configuration. Examples of PLDs include PAL (Programmable Array Logic), GAL (Generic Array Logic), CPLD (Complex Programmable Logic Device), FPGA (Field Programmable Gate Array), etc. In this case, some or all of the functions implemented by the processor may be implemented by the integrated circuit.

[0054] Examples of storage 93 include HDDs (Hard Disk Drives), SSDs (Solid State Drives), magnetic disks, magneto-optical disks, CD-ROMs (Compact Disc Read Only Memory), DVD-ROMs (Digital Versatile Disc Read Only Memory), and semiconductor memory. Storage 93 may be an internal medium directly connected to the bus of the computer 90, or an external medium connected to the computer 90 via an interface 94 or a communication line. Furthermore, if this program is distributed to the computer 90 via a communication line, the computer 90 that receives the program may expand it into main memory 92 and execute the above processing. In at least one embodiment, storage 93 is a tangible storage medium that is not temporary.

[0055] <Note> The operating method of the gas turbine plant and the control device 2 of the gas turbine plant in this embodiment can be understood, for example, as follows.

[0056] (1) A method for operating a gas turbine plant according to the first embodiment is a method for operating a gas turbine plant comprising: a gas turbine 10 having a combustor 12 provided with nozzles 60 for injecting fuel gas and fuel oil; a fuel gas system 30 for supplying the fuel gas to the nozzles; and a fuel oil system 40 for supplying the fuel oil to the nozzles, wherein when switching from a state in which the gas turbine is operated by supplying the fuel oil from the fuel oil system to the nozzles to operate the gas turbine, the fuel oil system After stopping the supply of the fuel oil from the fuel oil system to the nozzle, a first process is performed to discharge the fuel oil remaining in the nozzle. If combustion in the combustor is stopped when the gas turbine is operating by supplying the fuel oil from the fuel oil system to the nozzle, or if combustion in the combustor is stopped when the gas turbine is operating by supplying the fuel gas from the fuel gas system to the nozzle, and the first process was not completed normally during the preceding switchover, a second process is performed to discharge the fuel oil remaining in the nozzle. According to this embodiment and the following embodiments, the reliability of purging residual oil can be improved.

[0057] (2) The second method of operating the gas turbine plant is the method of operating the gas turbine plant of (1), wherein if the flag F, which is turned on during the switching and turned off when the first process is completed successfully, is not turned off, it is determined that the first process was not completed successfully.

[0058] (3) The third embodiment of the gas turbine plant operation method is the gas turbine plant operation method of (2), wherein the flag is turned on automatically or manually after the start of the switching.

[0059] (4) A gas turbine plant operating method according to the fourth embodiment is the gas turbine plant operating method according to (1) to (3), wherein the second process includes a process of discharging the fuel oil remaining in the nozzle from the tip of the nozzle toward the fuel oil system using the residual pressure in the gas turbine casing. [Explanation of Symbols]

[0060] 1…Gas turbine power plant (gas turbine plant) 2…Control device 3…Fuel gas supply device 4…Fuel oil supply device 5…Purge fluid supply device 6…Fuel oil recovery device 10... Gas turbine 11…Air compressor 12… Combustor 13... Turbine 14…Rota 15…Generator 18... Combustion chamber 19...Inner cylinder of the combustion chamber 21...First Control Unit 22...Second Control Unit 23...Storage section 30…Fuel gas system 32, 42, 52... Flow control valves 40…Fuel oil system 60... Nozzle 61-1, 61-2, 62-1, 62-2...Injection hole 62...Shut-off valve

Claims

1. A gas turbine having a combustor equipped with nozzles for injecting fuel gas and fuel oil, A fuel gas system that supplies the fuel gas to the nozzle, A fuel oil system that supplies the fuel oil to the nozzle, A method for operating a gas turbine plant, comprising: When switching from a state in which the gas turbine is operated by supplying the fuel oil from the fuel oil system to the nozzle to operate the gas turbine by supplying the fuel gas from the fuel gas system to the nozzle, a first process is performed in which the supply of the fuel oil from the fuel oil system to the nozzle is stopped, and then the fuel oil remaining in the nozzle is discharged. When the combustion in the combustor is stopped from a state in which the gas turbine is being operated by supplying the fuel oil from the fuel oil system to the nozzle, and when the combustion in the combustor is stopped from a state in which the gas turbine is being operated by supplying the fuel gas from the fuel gas system to the nozzle, and the first process was not completed normally during the preceding switchover, a second process is performed to discharge the fuel oil remaining in the nozzle, A method for operating a gas turbine plant.

2. If the flag that is turned on during the aforementioned switching and turned off when the first process is successfully completed is not turned off, it is determined that the first process was not successfully completed. A method for operating a gas turbine plant according to claim 1.

3. The aforementioned flag is turned on automatically or manually after the start of the switching process. A method for operating a gas turbine plant according to claim 2.

4. The second process includes a process of discharging the fuel oil remaining in the nozzle from the tip of the nozzle toward the fuel oil system using the residual pressure in the gas turbine cabin. A method for operating a gas turbine plant according to any one of claims 1 to 3.

5. A gas turbine having a combustor equipped with nozzles for injecting fuel gas and fuel oil, A fuel gas system that supplies the fuel gas to the nozzle, A fuel oil system that supplies the fuel oil to the nozzle, A control device for a gas turbine plant, comprising: A first control unit, which, when switching from a state in which the gas turbine is operated by supplying the fuel oil from the fuel oil system to the nozzle, to a state in which the gas turbine is operated by supplying the fuel gas from the fuel gas system to the nozzle, stops the supply of the fuel oil from the fuel oil system to the nozzle and then discharges the fuel oil remaining in the nozzle, When the combustion in the combustor is stopped from a state in which the gas turbine is being operated by supplying the fuel oil from the fuel oil system to the nozzle, and when the combustion in the combustor is stopped from a state in which the gas turbine is being operated by supplying the fuel gas from the fuel gas system to the nozzle, and the processing of the first control unit was not completed normally during the preceding switchover, the second control unit discharges the fuel oil remaining in the nozzle, A control system for a gas turbine plant equipped with the following features.

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