Gas turbine system and gas turbine system operation method

Abstract

This prevents ignition failures during startup of gas turbines using oil fuel. [Solution] This disclosure relates to a gas turbine system comprising a gas turbine having a fuel injection nozzle capable of injecting gaseous fuel or oil fuel into a combustion chamber. The gas turbine system comprises a gaseous fuel supply system capable of supplying gaseous fuel via a gaseous fuel supply line, an oil fuel supply system capable of supplying oil fuel via an oil fuel supply line, a purge air supply system capable of supplying purge air to the oil fuel supply line, and a purge air supply system control unit for controlling the purge air supply system. The purge air supply system control unit controls the purge air supply system so that purge air is supplied to the oil fuel supply line before starting up a gas turbine using oil fuel.

Description

Technical Field

[0001] The present disclosure relates to a gas turbine system and a method for operating a gas turbine system.

Background Art

[0002] There is known a gas turbine that can drive a turbine using combustion gas generated by combustion of fuel as a working fluid. Conventionally, gas turbines using various fuels have been developed, and there is a so-called dual-firing-capable gas turbine that can selectively switch between gas fuel and oil fuel according to the situation as needed (for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] According to the verification of the inventor of the present application, in the above-described dual-firing-capable gas turbine, when the gas turbine is stopped after operating using gas fuel as fuel and then restarted using oil fuel as fuel, there is a risk of ignition failure (trip).

[0005] At least one embodiment of the present disclosure has been made in view of the above circumstances, and an object thereof is to provide a gas turbine system and a method for operating a gas turbine system capable of preventing ignition failure from occurring when starting a gas turbine using oil fuel.

Means for Solving the Problems

[0006] In order to solve the above problems, a gas turbine system according to at least one embodiment of the present disclosure A gas turbine having a fuel injection nozzle capable of injecting gaseous fuel or oil fuel into the combustion chamber, A gas fuel supply system capable of supplying the gas fuel to the fuel injection nozzle via a gas fuel supply line, An oil fuel supply system capable of supplying the oil fuel to the fuel injection nozzle via an oil fuel supply line, A purge air supply system capable of supplying purge air to the oil fuel supply line, A purge air supply system control unit for controlling the purge air supply system, Equipped with, The purge air supply system control unit controls the purge air supply system so that the purge air is supplied to the oil fuel supply line before the gas turbine using the oil fuel is started.

[0007] A gas turbine system operation method according to at least one embodiment of this disclosure solves the above problems. A gas turbine having a fuel injection nozzle capable of injecting gaseous fuel or oil fuel into the combustion chamber, A gas fuel supply system capable of supplying the gas fuel to the fuel injection nozzle via a gas fuel supply line, An oil fuel supply system capable of supplying the oil fuel to the fuel injection nozzle via an oil fuel supply line, A purge air supply system capable of supplying purge air to the oil fuel supply line, A gas turbine system operation method for operating a gas turbine system comprising: Before starting the gas turbine using the aforementioned oil fuel, the gas turbine system is operated to supply the purge air to the oil fuel supply line. [Effects of the Invention]

[0008] According to at least one embodiment of this disclosure, it is possible to provide a gas turbine system capable of preventing ignition failures from occurring when starting up an oil-fueled gas turbine, and a method for operating a gas turbine system. [Brief explanation of the drawing]

[0009] [Figure 1] This is an overall configuration diagram of a gas turbine system according to one embodiment. [Figure 2] Figure 1 is a schematic diagram showing one example configuration of the oil fuel supply system and the purge air supply system. [Figure 3] This is a block diagram showing the functional configuration of the control device in Figure 1. [Figure 4] This is a flowchart showing a gas turbine system operation method according to one embodiment. [Figure 5] Figure 4 is a graph showing the temporal changes in the rotational speed of the gas turbine and the amount of purge air supplied during startup, according to the gas turbine system operation method. [Modes for carrying out the invention]

[0010] Hereinafter, several embodiments of the present invention will be described with reference to the attached drawings. However, the configurations described as embodiments or shown in the drawings are not intended to limit the scope of the present invention, but are merely illustrative examples.

[0011] Figure 1 is an overall configuration diagram of a gas turbine system 1 according to one embodiment. The gas turbine system 1 comprises a gas turbine 10, a generator 12 capable of generating electricity when driven by the gas turbine 10, and a control device 100 for controlling the gas turbine 10.

[0012] The gas turbine 10 comprises a compressor 14, a combustor 16, and a turbine 18. In the combustor 16, compressed air generated by the compressor 14 is mixed and combusted with fuel supplied from the fuel supply system (gas fuel supply system 40 or oil fuel supply system 50) to produce combustion gas. The combustion gas generated in the combustor 16 is sent to the turbine 18, and the turbine 18 is driven as a working fluid. The power output from the turbine 18 is transmitted to the generator 12 to generate electricity.

[0013] The compressor 14 is configured to generate compressed air which is combustion air by compressing the air A sucked from the outside. The compressor 14 includes a compressor rotor 20 that rotates about the axis Ar, a compressor casing 22 that rotatably covers the compressor rotor 20, and an inlet guide vane (IGV) 24 provided at an inlet portion (suction port). The inlet guide vane 24 includes a plurality of guide vanes 24a and an actuator 24b capable of driving the plurality of guide vanes 24a. In the inlet guide vane 24, the flow rate of the air A sucked into the compressor casing 22 can be adjusted by driving the plurality of guide vanes 24a by the actuator 24b.

[0014] The turbine 18 includes a turbine rotor 26 that rotates about the axis Ar by the combustion gas generated in the combustor 16, and a turbine casing 27 that rotatably covers the turbine rotor 26. The turbine rotor 26 and the aforementioned compressor rotor 20 are rotatably connected to each other about the same axis Ar to form a gas turbine rotor 28. A generator 12 is connected to the gas turbine rotor 28.

[0015] The gas turbine 10 further includes an intermediate casing 30 and an exhaust casing 32. The intermediate casing 30 is disposed between the compressor casing 22 and the turbine casing 27 and connects the compressor casing 22 and the turbine casing 27. Compressed air discharged from the compressor 14 flows into the intermediate casing 30. The exhaust casing 32 is disposed on the side opposite to the intermediate casing 30 when viewed from the turbine casing 27. Exhaust gas, which is the combustion gas that has completed work in the turbine 18, is introduced into the exhaust casing 32.

[0016] The combustor 16 is configured to generate combustion gas for driving the turbine 18 by mixing and burning the compressed air generated by the compressor 14 and the fuel supplied from the fuel supply system (gas fuel supply system 40 or oil fuel supply system 50). A plurality of combustors 16 are provided along the circumferential direction of the axis Ar with respect to the intermediate casing 30 (in FIG. 1, one of the plurality of combustors 16 is typically shown).

[0017] In addition, an air-cooled type that can be cooled by the air introduced into the cabin (intermediate casing 30) of the gas turbine 10 is used for the combustor 16.

[0018] The gas turbine system 1 includes, as a fuel supply system, a gas fuel supply system 40 capable of supplying gas fuel Fg and an oil fuel supply system 50 capable of supplying oil fuel Fo. The combustor 16 includes a plurality of fuel injection nozzles 38 capable of injecting the fuel supplied from these fuel supply systems together with the compressed air supplied from the compressor 14. The fuel injection nozzle 38 is a so-called dual fuel injection nozzle that can use either the gas fuel supplied from the gas fuel supply system 40 or the oil fuel supplied from the oil fuel supply system 50 as fuel.

[0019] The gas fuel supply system 40 is configured to supply the gas fuel Fg from the gas fuel supply source 41 to the combustor 16 and has a gas fuel supply line 42 connected to the gas fuel supply source 41. A flow rate adjustment valve 43 for adjusting the flow rate of the gas fuel Fg and a shut-off valve 44 for shutting off the gas fuel Fg are provided on the gas fuel supply line 42. <00,00102>

[0020] The oil fuel supply system 50 is configured to supply the oil fuel Fo from the oil fuel supply source 51 to the combustor 16 and has an oil fuel supply line 52 connected to the oil fuel supply source 51. An oil fuel pump 53 for adjusting the supply amount of the oil fuel Fo, a shut-off valve 54 for shutting off the oil fuel Fo, and a flow rate adjustment valve 57 for adjusting the flow rate of the oil fuel Fo are provided on the oil fuel supply line 52.

[0021] Thus, the gas turbine 10 has two types of fuel supply systems (gas fuel supply system 40 and oil fuel supply system 50), and by controlling the open and closed states of shut-off valves 44 and 54, it is configured to be able to select either gas fuel Fg or oil fuel Fo as fuel for the combustor 16.

[0022] The gas turbine system 1 also includes a purge air supply system 60 for supplying purge air Ap to the oil fuel supply line 52. The purge air supply system 60 has a purge air supply line 62 for supplying purge air Ap from a purge air supply source 61. The purge air supply source 61 includes, for example, a compressor capable of compressing air taken in from the outside, in which case the purge air Ap is compressed air.

[0023] The purge air supply line 62 is configured such that one end is connected to the purge air supply source 61 and the other end joins the oil fuel supply line 52 downstream of the shut-off valve 54 and the flow control valve 57. This makes it possible to discharge condensed water accumulated in the area downstream of the shut-off valve 54 and the flow control valve 57 of the oil fuel supply line 52 when the oil fuel supply system 50 is not in use, by supplying purge air Ap to the area downstream of the shut-off valve 54 and the flow control valve 57, which are in a closed state, as will be described later.

[0024] Furthermore, the purge air supply line 62 is equipped with a flow control valve 63 for adjusting the flow rate of purge air Ap, and a shut-off valve 64 for shutting off the purge air Ap.

[0025] Now, with reference to Figure 2, the specific configurations of the aforementioned oil fuel supply system 50 and purge air supply system 60 will be explained. Figure 2 is a schematic diagram showing one example configuration of the oil fuel supply system 50 and purge air supply system 60 shown in Figure 1.

[0026] Figure 2 shows the multiple combustors 16 provided by the gas turbine 10. Each of the multiple combustors 16 comprises an outer cylinder 34 fixed to an intermediate casing 30, a combustion cylinder (or tail cylinder) 36 located inside the intermediate casing 30 that sends combustion gas into the combustion gas flow path of the turbine 18, and a plurality of fuel injection nozzles 38 for injecting fuel supplied from a fuel supply system (gas fuel supply system 40 or oil fuel supply system 50) and compressed air generated by a compressor 14 into a combustion chamber 37 located inside the combustion cylinder 36. The plurality of fuel injection nozzles 38 include a pilot fuel injection nozzle 38p located on the central axis Ak of ​​the combustion cylinder 36 and a plurality of main fuel injection nozzles 38m arranged at approximately equal intervals along the circumferential direction with respect to the pilot fuel injection nozzle 38p.

[0027] The oil fuel supply line 52 of the oil fuel supply system 50 branches downstream of the oil fuel pump 53 into a pilot fuel supply line 52p connected to a pilot fuel injection nozzle 38p and a main fuel supply line 52m connected to a main fuel injection nozzle 38m. The pilot fuel supply line 52p is connected to the pilot fuel injection nozzle 38p of each combustor 16 via several branch pipes 56p that further branch off from the manifold section 55p. The main fuel supply line 52m is connected to the main fuel injection nozzle 38m of each combustor 16 via several branch pipes 56m that further branch off from the manifold section 55m (in Figure 2, some of the configurations of the branch pipes 56m connected to each main fuel injection nozzle 38m are omitted for convenience to avoid complicating the illustration).

[0028] Furthermore, of the shut-off valves 54 and flow control valves 57 of the oil fuel supply system 50, the shut-off valve 54p and flow control valve 57p provided in the pilot fuel supply line 52p are located upstream of the manifold section 55p. On the other hand, the shut-off valve 54m and flow control valve 57m provided in the main fuel supply line 52m are located in each branch pipe 56m downstream of the manifold section 55m. In addition, in the configuration example shown in Figure 2, the purge air supply system 60 is configured such that the purge air supply line 62 merges between the shut-off valve 54p and flow control valve 57p of the pilot fuel supply line 52p and the manifold section 55p.

[0029] The control device 100 is a control unit for controlling the gas turbine 10 having the above configuration, and is composed of, for example, a CPU (Central Processing Unit), RAM (Random Access Memory), ROM (Read Only Memory), and a computer-readable storage medium. A series of processes for realizing various functions are stored in the storage medium in the form of a program, for example, and the CPU reads this program into the RAM and performs information processing and calculations to realize the various functions. The program may be pre-installed in ROM or other storage media, provided in a state where it is stored in a computer-readable storage medium, or distributed via wired or wireless communication means. Computer-readable storage media include magnetic disks, magneto-optical disks, CD-ROMs, DVD-ROMs, semiconductor memory, etc.

[0030] Figure 3 is a block diagram showing the functional configuration of the control device 100 in Figure 1. The control device 100 includes a start command acquisition unit 102, an operation parameter acquisition unit 104, and an operation control unit 106.

[0031] The start command acquisition unit 102 is configured to acquire a start command for the gas turbine 10 when it is stopped. The start command is a trigger signal to initiate start-up operation for the gas turbine 10 when it is stopped, and is transmitted, for example, when the start switch of the gas turbine 10 is operated by an operator. As mentioned above, the gas turbine 10 can use either gas fuel Fg or oil fuel Fo as fuel, so this start command includes information specifying the type of fuel to be used during start-up operation. In other words, the start command includes information specifying whether to use gas fuel Fg or oil fuel Fo to start the gas turbine 10.

[0032] The operation parameter acquisition unit 104 is configured to acquire operation parameters related to the operating state of the gas turbine 10. The operation parameters may be values ​​detected by any sensor installed on the gas turbine 10, control signals handled by the control device 100, or calculated values ​​using these.

[0033] The operation control unit 106 is configured to perform operation control of the gas turbine 10. The operation control performed by the operation control unit 106 includes not only normal operation control for normal operation of the gas turbine 10, but also stop operation control when stopping the gas turbine 10, and start operation control to start the gas turbine 10 from a stopped state triggered by the aforementioned start command. The operation control unit 106 for performing these various operation controls includes a gas fuel supply system control unit 108, an oil fuel supply system control unit 110, and a purge air supply system control unit 112.

[0034] The gas fuel supply system control unit 108 is configured to control the gas fuel supply system 40. When the gas turbine 10 is operated using gas fuel Fg, the gas fuel supply system control unit 108 controls the flow rate of gas fuel Fg by switching the shut-off valve 44 provided in the gas fuel supply line 42 to the open state and adjusting the opening degree of the flow rate control valve 43. When the gas turbine 10 is operated using oil fuel Fo, the gas fuel supply system control unit 108 shuts off the gas fuel Fg by switching the shut-off valve 44 provided in the gas fuel supply line 42 to the closed state.

[0035] The oil fuel supply system control unit 110 is configured to control the oil fuel supply system 50. When the gas turbine 10 is operated using oil fuel Fo, the oil fuel supply system control unit 110 controls the flow rate of oil fuel Fo by switching the shut-off valve 54 provided in the oil fuel supply line 52 to the open state and adjusting the opening degree of the flow rate control valve 57 located downstream of the shut-off valve 54. When the gas turbine 10 is operated using gas fuel Fg, the oil fuel supply system control unit 110 shuts off the oil fuel Fo by switching the shut-off valve 54 provided in the oil fuel supply line 52 to the closed state.

[0036] The purge air supply system control unit 112 is configured to control the purge air supply system 60. As described above, the purge air supply line 62 of the purge air supply system 60 is connected to the oil fuel supply line 52, and by supplying purge air Ap when starting the gas turbine 10 which is in a stopped state using oil fuel Fo, it is possible to discharge condensed water accumulated in the oil fuel supply line 52.

[0037] In the gas turbine 10 having the above configuration, there was a risk of ignition failure when starting from a stopped state using oil fuel Fo. This is presumed to be because, while the gas turbine 10 is operating using gas fuel Fg before being stopped, water vapor generated inside the combustion chamber 37 enters the oil fuel supply line 52, where the oil fuel Fo is shut off, and condenses, accumulating as condensed water in the oil fuel supply line 52. The condensed water accumulated in the oil fuel supply line 52 is discharged into the combustion chamber 37 when the start control using oil fuel Fo begins, which can lead to ignition failure.

[0038] Furthermore, if the combustor 16 is a steam-cooled type that can be cooled by steam, it is conceivable that condensed water may accumulate in the oil fuel supply line 52 due to the steam leaking from the combustor 16. However, according to the inventor's verification, it has been found that even with an air-cooled combustor 16, as described above, there is a possibility that condensed water may accumulate in the oil fuel supply line 52 during gas-fired operation. Such problems can be suitably solved by the gas turbine system control method implemented by the control device 100 described below.

[0039] Next, a gas turbine system operation method implemented by the control device 100 having the above configuration will be described. Figure 4 is a flowchart showing a gas turbine system operation method according to one embodiment, and Figure 5 is a graph showing the temporal changes in the rotational speed R of the gas turbine 10 and the supply amount of purge air Ap during startup according to the gas turbine system operation method of Figure 4.

[0040] In the following explanation, the initial state of the gas turbine 10 is that it was operated using gaseous fuel Fg during the previous operation and is now in a stopped state.

[0041] First, the control device 100 determines in the start command acquisition unit 102 whether or not a start command has been acquired to start the gas turbine 10 using oil fuel Fo (step S100). As mentioned above, the start command includes information to select whether the fuel used when starting the gas turbine 10 is gas fuel Fg or oil fuel Fo. If a start signal is acquired to start the gas turbine 10 using oil fuel Fo (step S100: YES), the control device 100 starts executing the start sequence corresponding to the start control using oil fuel Fo (step S101).

[0042] In this startup sequence, the gas turbine 10, which is currently stopped, is first started by a starting device (not shown), thereby increasing the rotational speed R of the gas turbine 10 (step S102). In the example in Figure 6, after a start command is received at time t1, the startup sequence begins, and the rotational speed R of the gas turbine 10 gradually increases from time t2.

[0043] Next, the purge air supply system control unit 112 controls the purge air supply system 60 to supply purge air Ap to the oil fuel supply line 52, where the oil fuel Fo is shut off (step S103). At this time, in the stopped gas turbine 10, the supply of oil fuel Fo from the oil fuel supply system 50 has not yet begun, so the shut-off valve 54 is closed. Therefore, the purge air Ap from the purge air supply system 60 is supplied to the part of the pilot fuel supply line 52p downstream of the shut-off valve 54p. In this area, as described above with reference to Figure 4, there is a possibility that condensed water generated when the gas turbine 10 was operated using gas fuel Fg in the past has accumulated. However, by supplying purge air Ap in this way, the condensed water accumulated in the pilot fuel supply line 52p can be discharged to the combustion chamber 37 of the combustor 16 via the manifold section 55p and branch pipes 56p.

[0044] The supply of purge air Ap in step S103 may be carried out multiple times at predetermined time intervals. In the embodiment shown in Figure 6, purge air Ap is supplied multiple times between time t3 and time t4. By supplying purge air Ap intermittently in this way, the flow velocity of the purge air Ap supplied to the oil fuel supply line 52 is increased, and condensed water accumulated in the oil fuel supply line 52 can be effectively discharged.

[0045] Next, once the supply of purge air Ap is complete, the supply of oil fuel Fo to the oil fuel supply line 52 is started at time t4 (step S104). The supply of oil fuel Fo in step S104 is started on the condition that the supply of purge air Ap in step S103 is completed. This effectively avoids the situation in the startup sequence of the gas turbine 10 using oil fuel Fo where the supply of oil fuel Fo is started while purge air Ap is being supplied to the oil fuel supply line 52.

[0046] Next, at time t5 (for example, when the oil fuel Fo supplied in step S104 reaches the fuel injection nozzle 38), the oil fuel Fo supplied to the oil fuel supply line 52 is injected from the fuel injection nozzle 38 into the combustion chamber and ignited, thereby increasing the rotational speed of the gas turbine 10 (step S105). Then, at time t6, when the rotational speed R of the gas turbine 10 reaches a predetermined target rotational speed (for example, rated rotational speed) (step S106: YES), the series of startup sequences is completed and the system transitions to normal operation (step S107).

[0047] As described above, according to the above embodiment, when starting the gas turbine 10 using oil fuel Fo, purge air Ap is supplied to the oil fuel supply line 52, thereby discharging condensed water that has accumulated in the oil fuel supply line 52 during previous operation using gas fuel Fg into the combustion chamber 37. This effectively prevents ignition failures from occurring during startup using oil fuel Fo due to condensed water accumulated in the oil fuel supply line 52.

[0048] Furthermore, in the above-described embodiment, the example given was that when starting the gas turbine 10 using oil fuel Fo, purge air Ap is supplied to the oil fuel supply line 52 as part of the startup sequence. However, the supply of purge air Ap to the oil fuel supply line 52 may also be performed as part of the shutdown sequence when stopping the gas turbine 10 using gas fuel Fg. In this case, when the gas turbine 10 operating with gas fuel Fg is stopped, purge air Ap is supplied to the oil fuel supply line 52, which was in a shut-off state, to discharge the condensed water accumulated in the oil fuel supply line 52. This effectively prevents ignition failure due to condensed water accumulated in the oil fuel supply line 52 when starting the stopped gas turbine 10 using oil fuel Fo in the next instance.

[0049] Furthermore, if the supply of purge air Ap is implemented as part of the gas turbine 10 shutdown sequence, the supply of purge air Ap will also be performed when the gas turbine 10 is started using gas fuel Fg in subsequent starts, which may increase the frequency of purge air Ap supply. On the other hand, by discharging the condensed water that accumulates in the oil fuel supply line 52 when the gas turbine 10 is stopped, it is possible to more reliably prevent ignition failures during subsequent starts, and the responsiveness of the gas turbine 10 can be improved by shortening the time required to implement the startup sequence.

[0050] Furthermore, it is possible to replace the components in the above-described embodiments with well-known components as appropriate, without departing from the spirit of this disclosure, and the above-described embodiments may also be combined as appropriate.

[0051] The contents described in each of the above embodiments can be understood, for example, as follows:

[0052] (1) A gas turbine system according to one embodiment is: A gas turbine having a fuel injection nozzle capable of injecting gaseous fuel or oil fuel into the combustion chamber, A gas fuel supply system capable of supplying the gas fuel to the fuel injection nozzle via a gas fuel supply line, An oil fuel supply system capable of supplying the oil fuel to the fuel injection nozzle via an oil fuel supply line, A purge air supply system capable of supplying purge air to the oil fuel supply line, A purge air supply system control unit for controlling the purge air supply system, Equipped with, The purge air supply system control unit controls the purge air supply system so that the purge air is supplied to the oil fuel supply line before the gas turbine using the oil fuel is started.

[0053] In a dual-firing gas turbine capable of using both gas and oil fuel, there is a risk of ignition failure when the gas turbine is stopped after operation using gas fuel and then restarted using oil fuel. The inventors of this invention investigated this ignition failure and found that while the gas turbine is operating with gas fuel, moisture in the atmosphere condenses and accumulates in the unused oil fuel supply line. When restarting with oil fuel, this accumulated condensed water may cause poor ignition of the oil fuel. More specifically, it is thought that the condensed water accumulated in the oil fuel supply line causes variations in the amount of oil fuel supplied among the multiple combustors of the gas turbine. In some combustors where the deviation in the amount of oil fuel supplied becomes excessive, the combustion state changes, leading to ignition failure and tripping.

[0054] According to the embodiment of (1) above, by supplying purge air to the oil fuel supply line before starting up the gas turbine using oil fuel, condensed water accumulated in the oil fuel supply line is discharged into the combustion chamber. This effectively prevents ignition failures from occurring during the startup of the gas turbine using oil fuel due to condensed water accumulated in the oil fuel supply line.

[0055] (2) In other embodiments, in the embodiment of (1) above, The purge air supply system control unit controls the purge air supply system so that the purge air is supplied to the oil fuel supply line before starting the gas turbine, which is in a stopped state and was operated using the gas fuel during the previous operation, using the oil fuel.

[0056] According to the embodiment of (2) above, before restarting a gas turbine that is in a stopped state and was previously operated using gas fuel, using oil fuel, purge air is supplied to the oil fuel supply line. This effectively prevents ignition failures from occurring when starting up an oil-fueled gas turbine by using purge air to discharge condensate that has accumulated in the oil fuel supply line during gas fuel operation before starting up with oil fuel.

[0057] (3) In other embodiments, in the embodiment of (1) or (2) above, The purge air supply system control unit supplies the purge air as part of the startup sequence when the gas turbine is started using the oil fuel.

[0058] According to the embodiment of (3) above, the purge air supply control described above is performed as part of the startup sequence of a gas turbine using oil fuel. By limiting the purge air supply control to cases where the gas turbine is started using oil fuel, it is possible to reduce the number of operations of the purge air supply system and effectively prevent ignition failures due to condensed water accumulating in the oil fuel supply line, compared to the case where purge air is supplied every time the gas turbine is started.

[0059] (4) In other embodiments, in the embodiment of (3) above, In the aforementioned startup sequence, the supply of oil fuel to the fuel injection nozzle is started, provided that the supply of the purge air is completed.

[0060] According to the embodiment of (4) above, in the startup sequence of a gas turbine using oil fuel, the supply of oil fuel is started on the condition that the supply of purge air is completed. This effectively avoids the situation in which the supply of oil fuel is started while purge air is being supplied to the oil fuel supply line.

[0061] (5) In other embodiments, in any one embodiment of (1) to (4) above, The purge air supply system control unit controls the purge air supply system so that the supply of purge air is carried out multiple times at predetermined time intervals.

[0062] According to the embodiment of (5) above, by intermittently supplying purge air, the flow velocity of the supplied purge air can be increased, and condensed water accumulated in the oil fuel supply line can be effectively discharged.

[0063] (6) In other embodiments, in any one embodiment of (1) to (5) above, The oil fuel supply line communicates with the fuel injection nozzles provided in each of the multiple combustors of the gas turbine via a plurality of branch pipes that branch off from the manifold.

[0064] According to the embodiment of (6) above, the oil fuel supply line to which purge air is supplied communicates with fuel injection nozzles provided in each combustor via branch pipes branched from the manifold. In this configuration, as the atmosphere from each combustor is introduced into the oil fuel supply line via branch pipes and the manifold, moisture contained in the atmosphere may condense and produce condensed water. However, as described above, by supplying purge air before starting the gas turbine using oil fuel, the condensed water accumulated in the oil fuel supply line can be discharged, effectively preventing ignition failure.

[0065] (7) In other embodiments, in the embodiment of (6) above, The aforementioned combustors are air-cooled.

[0066] According to the inventor's verification, it was found that even when the multiple combustors of a gas turbine are air-cooled and can be cooled by air introduced into the casing, condensed water can still accumulate in the oil fuel supply line. According to the embodiment of (7) above, in a gas turbine system equipped with such air-cooled combustors, supplying purge air before starting with oil fuel can effectively prevent ignition failure by discharging the condensed water accumulated in the oil fuel supply line.

[0067] (8) A gas turbine system operation method according to one embodiment is: A gas turbine having a fuel injection nozzle capable of injecting gaseous fuel or oil fuel into the combustion chamber, A gas fuel supply system capable of supplying the gas fuel to the fuel injection nozzle via a gas fuel supply line, An oil fuel supply system capable of supplying the oil fuel to the fuel injection nozzle via an oil fuel supply line, A purge air supply system capable of supplying purge air to the oil fuel supply line, A gas turbine system operation method for operating a gas turbine system comprising: Before starting the gas turbine using the aforementioned oil fuel, the gas turbine system is operated to supply the purge air to the oil fuel supply line.

[0068] According to the embodiment of (8) above, by supplying purge air to the oil fuel supply line before starting up the oil fuel gas turbine, condensed water accumulated in the oil fuel supply line is discharged into the combustion chamber. This effectively prevents ignition failures from occurring during the startup of the oil fuel gas turbine due to condensed water accumulated in the oil fuel supply line. [Explanation of symbols]

[0069] 1. Gas Turbine System 10 Gas Turbines 12 Generators 14 Compressor 16 Combustor 18 Turbines 20 Compressor Rotor 22 Compressor casing 24 Entrance Information Wing 24a Guide vane 24b Actuator 26 Turbine rotor 27 Turbine Casing 28 Gas turbine rotor 30 Intermediate casing 32 Exhaust casing 34 Outer cylinder 36 Combustion cylinder 37 Combustion chamber 38 Fuel Injection Nozzles 38m Main Fuel Injection Nozzle 38p Pilot fuel injection nozzle 40 Gas fuel supply system 41. Gas fuel supply sources 42 Gas fuel supply lines 43 Flow control valve 44 Shut-off valve 50 Oil fuel supply system 51 Oil Fuel Source 52 Oil fuel supply lines 52m Main fuel supply line 52p Pilot fuel supply line 53 Oil fuel pump 54 Shut-off valve 55m, 55p Manifold section 56m,56p Branch pipe 57 Flow control valve 60 Purge air supply system 61. Purge air supply source 62 Purge air supply line 63 Flow control valve 64 Shut-off valve 100 Control device 102 Startup command acquisition unit 104 Operation parameter acquisition unit 106 Operation Control Unit 108 Gas Fuel Supply System Control Unit 110 Oil Fuel Supply System Control Unit 112 Purge Air Supply System Control Unit Ap Purge Air Fg gas fuel Fo oil fuel

Claims

1. A gas turbine having a fuel injection nozzle capable of injecting gaseous fuel or oil fuel into the combustion chamber, A gas fuel supply system capable of supplying the gas fuel to the fuel injection nozzle via a gas fuel supply line, An oil fuel supply system capable of supplying the oil fuel to the fuel injection nozzle via an oil fuel supply line, A purge air supply system capable of supplying purge air to the oil fuel supply line, A purge air supply system control unit for controlling the purge air supply system, Equipped with, A gas turbine system in which the purge air supply system control unit controls the purge air supply system so that the purge air is supplied to the oil fuel supply line before the gas turbine using the oil fuel is started up.

2. The gas turbine system according to claim 1, wherein the purge air supply system control unit controls the purge air supply system so that the purge air is supplied to the oil fuel supply line before starting the gas turbine, which is in a stopped state and was operated using the gas fuel during the previous operation, using the oil fuel.

3. The gas turbine system according to claim 1 or 2, wherein the purge air supply system control unit performs the supply of the purge air as part of the startup sequence when the gas turbine is started using the oil fuel.

4. The gas turbine system according to claim 3, wherein the startup sequence starts supplying the oil fuel to the fuel injection nozzles on the condition that the supply of the purge air is completed.

5. The gas turbine system according to claim 1 or 2, wherein the purge air supply system control unit controls the purge air supply system so that the supply of purge air is carried out multiple times at predetermined time intervals.

6. The gas turbine system according to claim 1 or 2, wherein the oil fuel supply line communicates with the fuel injection nozzles provided in each of the multiple combustors of the gas turbine via a plurality of branch pipes branching off from the manifold.

7. The gas turbine system according to claim 6, wherein the plurality of combustors are air-cooled.

8. A gas turbine having a fuel injection nozzle capable of injecting gaseous fuel or oil fuel into the combustion chamber, A gas fuel supply system capable of supplying the gas fuel to the fuel injection nozzle via a gas fuel supply line, An oil fuel supply system capable of supplying the oil fuel to the fuel injection nozzle via an oil fuel supply line, A purge air supply system capable of supplying purge air to the oil fuel supply line, A gas turbine system operation method for operating a gas turbine system comprising: A method for operating a gas turbine system, comprising operating the gas turbine system so as to supply the purge air to the oil fuel supply line before starting up the gas turbine using the oil fuel.

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