Gas turbine starting method, and gas turbine

Abstract

To make improvement of emission performance and suppression of combustion vibration compatible with each other when starting a gas turbine.SOLUTION: The current invention relates to a gas turbine starting method for starting a gas turbine having a combustor with a plurality of fuel injection nozzles for jetting fuel to a combustion chamber. In the method, the gas turbine is started by driving an electric power generator coupled to the gas turbine having a starter, and fuel is jetted by a part of the plurality of fuel injection nozzles to increase the number of rotations of the gas turbine. The starter is stopped when the number of rotations of the gas turbine has reached a reference number of rotations equal to or larger than an upper limit number of rotations within a range of the number of rotation causing the gas turbine combustion vibration.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present disclosure relates to a gas turbine start-up method and a gas turbine. [Background technology]

[0002] A gas turbine is known that can drive a turbine using combustion gas generated by burning fuel in a combustor. In the combustor of a gas turbine, fuel supplied from a fuel supply system is injected into a combustion chamber through multiple fuel injection nozzles, and the fuel is mixed with combustion air and combusted to generate combustion gas.

[0003] In this type of gas turbine, environmental performance is required to reduce emissions of nitrogen oxides (NOx), etc., which is to say, improve emissions performance. In response to this, Patent Document 1 proposes that during partial load operation, fuel is injected from some of the multiple fuel injection nozzles provided in the combustor, thereby increasing the fuel injection amount per fuel injection nozzle and raising the combustion temperature, thereby reducing nitrogen oxide emissions. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-145073 Summary of the Invention [Problem to be solved by the invention]

[0005] In recent years, the importance of such emission performance has also increased during the start-up of gas turbines. One possible solution is to apply the technology for partial load operation disclosed in Patent Document 1 to the start-up of gas turbines. However, when fuel is injected from some of the fuel injection nozzles of the combustor during start-up of a gas turbine, the combustion temperature rises. Therefore, when the rotation speed of a gas turbine increases during start-up and reaches a relatively high rotation speed operating range, combustion oscillation may be more likely to occur.

[0006] At least one embodiment of the present application has been made in consideration of the above circumstances, and an object of the present application is to provide a gas turbine start-up method and a gas turbine that can achieve both improved emission performance and suppression of combustion oscillation during startup. [Means for solving the problem]

[0007] In order to solve the above problem, a gas turbine start-up method according to at least one embodiment of the present disclosure includes: 1. A gas turbine start-up method for starting a gas turbine having a combustor with a plurality of fuel injection nozzles for injecting fuel into a combustion chamber, comprising: starting the gas turbine by driving a generator coupled to the gas turbine with a starting device; increasing a rotation speed of the gas turbine by injecting the fuel from some of the plurality of fuel injection nozzles; stopping the starting device when the rotation speed of the gas turbine reaches or exceeds a reference rotation speed that is greater than an upper limit rotation speed of a rotation speed range at which combustion oscillation occurs in the gas turbine; Equipped with.

[0008] In order to solve the above problems, a gas turbine according to at least one embodiment of the present disclosure includes: 1. A gas turbine having a combustor with a plurality of fuel injection nozzles for injecting fuel into a combustion chamber, a starting device for starting the gas turbine by driving a generator coupled to the gas turbine; a combustor control unit for controlling the combustor; a start-up device control unit for controlling the start-up device; Equipped with the combustor control unit controls the combustor to inject the fuel from some of the plurality of fuel injection nozzles after the gas turbine is started by the starting device, The starting device control unit controls the starting device to stop when the rotation speed of the gas turbine reaches or exceeds a reference rotation speed that is greater than an upper limit rotation speed of a rotation speed range at which combustion oscillation occurs in the gas turbine. [Effects of the Invention]

[0009] According to at least one embodiment of the present disclosure, it is possible to provide a gas turbine start-up method and a gas turbine that can achieve both improved emission performance and suppression of combustion oscillation during startup. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a schematic configuration diagram of a gas turbine power generation facility according to an embodiment. [Figure 2] FIG. 2 is a vertical cross-sectional view showing a schematic configuration of the combustor of FIG. [Figure 3] FIG. 3 is a view showing the combustor shown in FIG. 2 from the downstream side. [Figure 4] FIG. 2 is a block diagram of a control device for controlling the gas turbine power generation facility of FIG. [Figure 5] 1 is a timing chart showing the transition of each parameter when a gas turbine start-up method according to a reference technique is performed. [Figure 6] 5 is a timing chart showing the transition of each parameter during the gas turbine startup method performed by the control device of FIG. 4. DETAILED DESCRIPTION OF THE INVENTION

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

[0012] 1 is a schematic configuration diagram of a gas turbine power generation facility 1 according to one embodiment. The gas turbine power generation facility 1 includes a gas turbine 2, a generator 4, and a starting device 6.

[0013] The gas turbine 2 includes a fuel supply system 8, a compressor 10, a combustor 12, and a turbine 14. The fuel supply system 8 is configured to supply fuel F from a fuel supply source 16, and has a fuel supply line 18 provided with a flow rate control valve V1 for adjusting the flow rate of the fuel F and a shutoff valve V2 for shutting off the fuel F. The flow rate control valve V1 and the shutoff valve V2 have their openings controlled based on control signals from a control device 100, which will be described later, thereby making it possible to adjust the amount of fuel F supplied by the fuel supply system 8. The compressor 10 is also capable of drawing in air (atmospheric air) from the outside as combustion air A to generate compressed air.

[0014] The combustor 12 generates combustion gas Gc by mixing and burning fuel F supplied from a fuel supply system 8 and combustion air A supplied from a compressor 10. The combustion gas Gc generated in the combustor 12 is supplied to a turbine 14, thereby enabling the turbine 14 to be driven. An output shaft 20 of the turbine 14 is connected to a generator 4, and power is generated using the rotational energy of the turbine 14. The generator 4 is electrically connected to an electric power system 22, and the electric power generated by the power generation can be supplied to the electric power system 22.

[0015] The starting device 6 is configured to start the gas turbine 2. Specifically, the starting device 6 is a thyristor starting device electrically connected to the generator 4, and is capable of driving the generator 4 as an electric motor using electric power from the power grid 22. The generator 4 is connected to the turbine 14 via the output shaft 20, and therefore the generator 4 driven by the electric motor can impart starting torque to the turbine 14 via the output shaft 20. Although a detailed description of the circuit configuration of the starter device 6 will be omitted, for example, the configuration disclosed in Japanese Patent Laid-Open Publication No. 6-159098 can be adopted.

[0016] The configuration of the combustor 12 will now be described with reference to Figures 2 and 3. Figure 2 is a vertical cross-sectional view showing a schematic configuration of the combustor 12 of Figure 1, and Figure 3 is a view showing the combustor 12 shown in Figure 2 from the downstream side.

[0017] The combustor 12 is equipped with a plurality of fuel injection nozzles 26 for injecting the fuel F supplied from the fuel supply system 8 into the combustion chamber 24. These fuel injection nozzles are arranged inside an inner cylinder 28, and form a premixture of the injected fuel F and the combustion air A supplied from the compressor 10, and inject the premixture into the combustion chamber 24 defined by a transition piece 32 on the downstream side.

[0018] 3, the multiple fuel injection nozzles 26 include a pilot nozzle 26A and a main nozzle 26B. The pilot nozzle 26A is disposed at the axial center of the inner cylinder 28 and communicates with a pilot cone 29. The main nozzles 26B are disposed radially outward from the pilot nozzle 26A along the circumferential direction and communicate with the main burner 27. In this embodiment, eight main nozzles 26B are disposed at equal angular intervals along the circumferential direction.

[0019] 2, a pilot swirler 30 is provided on the outer circumferential side near the tip of the pilot nozzle 26A between the pilot cone 29. A main swirler 31 is provided on the outer circumferential side near the tip of the main nozzle 26B between the main burner 27.

[0020] Of the fuel F supplied from the fuel supply system 8 to the combustor 12, the pilot fuel supplied to the pilot nozzle 26A is injected from the pilot nozzle 26A to generate a pilot flame (diffusion flame) in the combustion chamber 24. On the other hand, of the fuel F supplied from the fuel supply system 8 to the combustor 12, the main fuel supplied to the main nozzle 26B forms a premixed air-fuel mixture in the main burner 27 and is injected into the combustion chamber 24. As a result, in the combustion chamber 24, the premixed air-fuel mixture is ignited by the pilot flame, generating a premixed flame.

[0021] In the gas turbine 2 having the above configuration, at startup, fuel is injected from some of the multiple main nozzles 26B in the combustor 12. Specifically, the multiple main nozzles 26B are classified into a first main nozzle group 26B1 and a second main nozzle group 26B2 that can independently adjust the amount of fuel supplied from the fuel supply system 8, and at startup of the gas turbine 2, fuel is injected only from the second main nozzle group 26B2 out of the first main nozzle group 26B1 and the second main nozzle group 26B2. This increases the amount of fuel injected from each main nozzle 26B, and increases the combustion temperature in the combustion chamber 24, thereby enabling a reduction in nitrogen oxide emissions.

[0022] The number of main nozzles 26B belonging to the second main nozzle group 26B2 is smaller than the number of main nozzles 26B belonging to the first main nozzle group 26B1. In the configuration example shown in Fig. 3, the multiple main nozzles 26B included in the combustor 12 are classified into a first main nozzle group 26B1 including five main nozzles 26B and a second main nozzle group 26B2 including three main nozzles 26B. In particular, the main nozzles 26B belonging to the second main nozzle group 26B2 are arranged below the main nozzles 26B belonging to the first main nozzle group 26B1.

[0023] Next, a control device 100 for controlling the gas turbine power generation facility 1 having the above-described configuration will be described. The control device 100 is a control unit for controlling the gas turbine power generation facility 1 described above, and is composed of, for example, a central processing unit (CPU), a random access memory (RAM), a read-only memory (ROM), and a computer-readable storage medium. A series of processes for realizing various functions is stored in a storage medium or the like in the form of a program, for example. The CPU reads the program into the RAM or the like and executes information processing and arithmetic operations to realize various functions. The program may be pre-installed in a ROM or other storage medium, provided in a state stored in a computer-readable storage medium, or distributed via wired or wireless communication means. Examples of computer-readable storage media include magnetic disks, magneto-optical disks, CD-ROMs, DVD-ROMs, and semiconductor memories.

[0024] Fig. 4 is a block diagram of a control device 100 for controlling the gas turbine power generation facility 1 of Fig. 1. The control device 100 includes an operation mode selection unit 102, a gas turbine control unit 104, and a starting device control unit 106.

[0025] The operation mode selection unit 102 is configured to select an operation mode of the gas turbine. In this embodiment, the operation modes selectable by the operation mode selection unit 102 include a startup mode and a normal operation mode. The startup mode is an operation mode selected when starting up the gas turbine 2 that is in a stopped state, and the normal operation mode is an operation mode selected when startup control in the startup mode is completed and the gas turbine transitions to normal operation. In the startup mode, the rate of change of the rotation speed when increasing the rotation speed (hereinafter referred to as the "speed-up rate RT") is set to be larger than in the normal operation mode, thereby enabling rapid startup. Specifically, a first speed-up rate RT1 is set as the speed-up rate RT in the normal operation mode, and a second speed-up rate RT2 that is larger than the first speed-up rate RT1 is set as the speed-up rate RT in the startup mode.

[0026] The gas turbine control unit 104 is configured to control the operating state of the gas turbine 2. Specifically, by adjusting the supply amounts of fuel F and combustion air A to the combustor 12 provided in the gas turbine 2, the gas turbine control unit 104 controls the operating state of the gas turbine 2 so that the rotation speed R changes at a predetermined speed-up rate RT. In particular, when the startup mode is selected as the operating mode by the operation mode selection unit 102, the gas turbine control unit 104 controls the fuel injection to be performed by some of the main nozzles 26B (the main nozzles 26B belonging to the second main nozzle group 26B2) among the multiple main nozzles 26B provided in the combustor 12, as described above with reference to FIG. 3. In this way, by increasing the fuel injection amount from each main nozzle 26B, the combustion temperature is increased, nitrogen oxide emissions at startup are reduced, and good emission performance can be obtained.

[0027] The starting device control unit 106 is configured to control the starting device 6. The starting device 6 rectifies the power from the power grid 22 and supplies it to the generator 4, thereby driving the generator 4 connected to the gas turbine 2 as an electric motor, and providing an output to the gas turbine 2 that is in a stopped state, thereby starting up the gas turbine 2. By controlling the starting device 6, the starting device control unit 106 can adjust the output provided to the gas turbine 2 at startup.

[0028] Next, a gas turbine startup method that can be implemented by the control device 100 will be described. First, a gas turbine startup method according to the reference technology will be described with reference to Fig. 5. Fig. 5 is a timing chart showing the transition of each parameter (the speed-up rate RT, the output of the starting device 6, the combustion temperature of the combustion chamber 24, and the casing pressure of the combustor 12) when the gas turbine startup method according to the reference technology is implemented.

[0029] First, at the start-up of the gas turbine 2, the start-up mode is selected by the operation mode selection unit 102. In the start-up mode, as described above, the second speed-up rate RT2, which is greater than the first speed-up rate RT1 corresponding to the normal operation mode, is set as the speed-up rate RT.

[0030] When the start-up mode is executed, the gas turbine 2, whose rotation speed R is zero in the initial state, is started by the start-up device 6. The operation of the start-up device 6 is controlled by the start-up device control unit 106 so that the speed-up rate RT of the gas turbine 2 becomes the second speed-up rate RT2.

[0031] When the rotation speed R reaches the first reference value Rref1, the gas turbine control unit 104 controls the gas turbine 2 to start supplying the fuel F from the fuel supply system 8 and the combustion air A from the compressor 10 to the combustor 12. As a result, the gas turbine 2 is controlled so that the rotation speed R is further increased at the second acceleration rate RT2 using both the output from the starting device 6 and the output obtained by driving the turbine with the combustion gas Gc generated in the combustor 12 (i.e., the gas turbine 2 is assisted-driven by the starting device 6).

[0032] Subsequently, when the rotation speed R reaches a second reference value Rref2 (>Rref1), the starting device control unit 106 controls the starting device 6 to stop. As a result, after the rotation speed R reaches the second reference value Rref2, the output of the starting device 6 is quickly reduced at a predetermined rate so as to reach zero. In this manner, in the range where the rotation speed R is relatively high, no output is provided from the starting device 6, and the gas turbine 2 is driven by the combustion gas Gc generated in the combustor 12, thereby controlling the rotation speed R to increase at the second acceleration rate RT2. Then, when the rotation speed R reaches the rated rotation speed Rm, the series of startup processes is completed, and the operation mode selection unit 102 switches from the startup mode to the normal operation mode, thereby transitioning to normal operation.

[0033] Here, when the rotational speed R is in the range from the second reference value Rref2 to a third reference value Rref3 which is between the second reference value Rref2 and the rated rotational speed Rm, the casing pressure of the combustor 12 temporarily increases sharply, as shown in Fig. 5, indicating that the high combustion temperature causes combustion oscillation in the combustor 12. Such combustion oscillation which occurs during gas turbine control in the startup mode can be preferably avoided by the startup method according to the present embodiment which will be described below.

[0034] FIG. 6 is a timing chart showing the transition of each parameter (the speed-up rate RT, the output of the starting device 6, the combustion temperature of the combustion chamber 24, and the casing pressure of the combustor 12) during the gas turbine startup method implemented by the control device 100 of FIG. 4.

[0035] In this embodiment, the rotational speed R reaches the second reference value Rref2 (>Rref1), as in the reference technology shown in FIG. 5 . However, the starting device 6 is not stopped until the rotational speed R reaches a third reference value Rref3, which is higher than the second reference value Rref2. That is, compared to the reference technology, the timing at which the starting device 6 is stopped is on the higher rotational speed side. This third reference value Rref3 is 90% or more of the rated rotational speed of the gas turbine 2 and may be the rated rotational speed (100%). Therefore, in the range in which the rotational speed R is between the second reference value Rref2 and the third reference value Rref3, the amount of fuel injected into the combustor is reduced by the amount of power provided by the starting device 6, and the combustion temperature is suppressed in this rotational speed range. As a result, as shown in FIG. 6 , combustion oscillation, as shown in the reference technology shown in FIG. 5 , does not occur in this rotational speed range.

[0036] As described above, according to the above embodiment, even when the emission performance at the time of rapid startup in the startup mode is improved by injecting fuel from some of the fuel injection nozzles of the combustor 12 in the gas turbine 2 started by the starting device 6, the occurrence of combustion oscillation can be suitably avoided by stopping the starting device 6 at the timing when the rotation speed R of the gas turbine 2 reaches the third reference value Rref3.

[0037] In addition, within the scope of the present disclosure, the components in the above-described embodiments may be replaced with well-known components as appropriate, and the above-described embodiments may be combined as appropriate.

[0038] The contents described in each of the above embodiments can be understood, for example, as follows.

[0039] (1) A gas turbine start-up method according to one aspect includes: 1. A gas turbine start-up method for starting a gas turbine having a combustor with a plurality of fuel injection nozzles for injecting fuel into a combustion chamber, comprising: starting the gas turbine by driving a generator coupled to the gas turbine with a starting device; increasing a rotation speed of the gas turbine by injecting the fuel from some of the plurality of fuel injection nozzles; stopping the starting device when the rotation speed of the gas turbine reaches or exceeds a reference rotation speed that is greater than an upper limit rotation speed of a rotation speed range at which combustion oscillation occurs in the gas turbine; Equipped with.

[0040] According to the above aspect (1), when the gas turbine is started by driving the generator using the starting device, the turbine is driven by the power provided by the starting device and the combustion gas generated by the fuel injected by the combustor, thereby increasing the speed of the gas turbine. By injecting fuel from some of the fuel injection nozzles of the combustor at this time, the fuel injection amount per fuel injection nozzle is increased compared to when fuel is injected from all of the fuel injection nozzles, thereby improving emission performance at startup. Meanwhile, by continuing to drive the electric motor using the starting device until the gas turbine rotation speed reaches or exceeds the reference rotation speed, the fuel injection amount in the rotation speed range where combustion oscillation is likely to occur is reduced by the amount of power provided by the starting device. As a result, the combustion temperature in that rotation speed range is suppressed, thereby avoiding the occurrence of combustion oscillation.

[0041] (2) In another embodiment, in the above embodiment (1), The reference rotation speed is 90% or more of the rated rotation speed of the turbine.

[0042] According to the above aspect (2), the starting device is controlled to be stopped when the rotation speed of the gas turbine reaches 90% or more of the rated rotation speed. As a result, by applying output to the gas turbine by the starting device until the rotation speed reaches 90% or more of the rated rotation speed, the fuel injection amount can be effectively reduced in the rotation speed range where combustion oscillation is likely to occur.

[0043] (3) In another embodiment, in the above embodiment (2), The reference rotation speed is the rated rotation speed.

[0044] According to the above aspect (3), the starting device is controlled to be stopped when the rotation speed of the gas turbine reaches the rated rotation speed (i.e., 100% of the rated rotation speed). As a result, by applying output to the gas turbine by the starting device until the rotation speed reaches the rated rotation speed, the fuel injection amount can be effectively reduced in the rotation speed range where combustion oscillation is likely to occur.

[0045] (4) In another embodiment, in any one of the above (1) to (3), The number of the partial fuel injection nozzles is equal to or less than half the number of the plurality of fuel injection nozzles.

[0046] According to the above aspect (4), in a combustor of a gas turbine started by a starting device, fuel is injected using half or less of the fuel injection nozzles of the combustor. This increases the fuel injection amount per fuel injection nozzle compared to a case in which fuel is injected from all of the fuel injection nozzles of the combustor, thereby making it possible to suitably improve emission performance at startup.

[0047] (5) In another embodiment, in any one of the above (1) to (4), The starting device is a thyristor starting device for driving the generator as an electric motor.

[0048] According to the above aspect (5), the gas turbine can be started by using the starting device configured as a thyristor starting device to drive the generator connected to the turbine.

[0049] (6) A gas turbine according to one aspect includes: 1. A gas turbine having a combustor with a plurality of fuel injection nozzles for injecting fuel into a combustion chamber, a starting device for starting the gas turbine by driving a generator coupled to the gas turbine; a combustor control unit for controlling the combustor; a start-up device control unit for controlling the start-up device; Equipped with the combustor control unit controls the combustor to inject the fuel from some of the plurality of fuel injection nozzles after the gas turbine is started by the starting device, The starting device control unit controls the starting device to stop when the rotation speed of the gas turbine reaches or exceeds a reference rotation speed that is greater than an upper limit rotation speed of a rotation speed range at which combustion oscillation occurs in the gas turbine.

[0050] According to the above aspect (6), when the gas turbine is started by driving the generator using the starting device, the turbine is driven by the power provided by the starting device and the combustion gas generated by the fuel injected by the combustor, thereby increasing the speed of the gas turbine. By injecting fuel from some of the fuel injection nozzles of the combustor at this time, the fuel injection amount per fuel injection nozzle is increased compared to when fuel is injected from all of the fuel injection nozzles, thereby improving emission performance at startup. Meanwhile, by continuing to drive the electric motor using the starting device until the gas turbine rotation speed reaches or exceeds the reference rotation speed, the fuel injection amount in the rotation speed range where combustion oscillation is likely to occur is reduced by the amount of power provided by the starting device. As a result, the combustion temperature in that rotation speed range is suppressed, thereby avoiding the occurrence of combustion oscillation. [Explanation of symbols]

[0051] 1. Gas turbine power generation equipment 2. Gas turbine 4. Generator 6 Starting device 8 Fuel supply system 10 Compressor 12 Combustor 14 Turbine 16 Fuel supply source 18 Fuel supply line 20 Output shaft 22 Power system 24 Combustion chamber 26 Fuel injection nozzle 26A Pilot Nozzle 26B Main Nozzle 26B1 1st main nozzle group 26B2 2nd main nozzle group 27 Main Burner 28 Inner cylinder 29 Pilot Cone 30 Pilot Swirl 31 Main Swara 32 Tailpiece 100 control device 102 Operation mode selection section 104 Gas turbine control unit 106 Starting device control section F fuel A Combustion air Gc Combustion gas

Claims

1. 1. A gas turbine start-up method for starting a gas turbine having a combustor with a plurality of fuel injection nozzles for injecting fuel into a combustion chamber, comprising: starting the gas turbine by driving a generator coupled to the gas turbine with a starting device; increasing a rotation speed of the gas turbine by injecting the fuel from some of the plurality of fuel injection nozzles; stopping the starting device when the rotation speed of the gas turbine reaches or exceeds a reference rotation speed that is greater than an upper limit rotation speed of a rotation speed range at which combustion oscillation occurs in the gas turbine; A gas turbine start-up method comprising:

2. 2. The gas turbine start-up method according to claim 1, wherein the reference rotational speed is 90% or more of a rated rotational speed of the turbine.

3. The gas turbine start-up method according to claim 2 , wherein the reference rotational speed is the rated rotational speed.

4. 3. The gas turbine start-up method according to claim 1, wherein the number of the part of fuel injection nozzles is equal to or less than half the number of the plurality of fuel injection nozzles.

5. 3. The gas turbine starting method according to claim 1, wherein the starting device is a thyristor starting device for driving the generator as an electric motor.

6. 1. A gas turbine having a combustor with a plurality of fuel injection nozzles for injecting fuel into a combustion chamber, a starting device for starting the gas turbine by driving a generator coupled to the gas turbine; a combustor control unit for controlling the combustor; a start-up device control unit for controlling the start-up device; Equipped with the combustor control unit controls the combustor to inject the fuel from some of the plurality of fuel injection nozzles after the gas turbine is started by the starting device, the starting device control unit controls the starting device to stop when the rotation speed of the gas turbine reaches or exceeds a reference rotation speed that is greater than an upper limit rotation speed of a rotation speed range at which combustion oscillation occurs in the gas turbine.

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