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

Abstract

A gas turbine control device according to at least one embodiment of the present disclosure comprises a purge gas flow rate control unit that controls the flow rate of purge gas for discharging fuel gas remaining inside the gas turbine to the outside of the gas turbine. The purge gas flow rate control unit controls the flow rate of the purge gas on the basis of a parameter related to the intake air quantity from a gas turbine inlet.

Description

[Technical Field]

[0001] The present disclosure relates to a gas turbine control device, a gas turbine, and a gas turbine control method. This application claims priority based on Japanese Patent Application No. 2022-008808, filed with the Japan Patent Office on January 24, 2022, the contents of which are incorporated herein by reference. [Background technology]

[0002] In a gas turbine that uses gaseous fuel as fuel, for example, when the gas turbine is stopped, in order to prevent the remaining fuel in the fuel pipe from burning within the fuel pipe, an inert gas such as nitrogen is purged into the fuel pipe to expel the gaseous fuel within the fuel pipe with the inert gas (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-082262 Summary of the Invention [Problem to be solved by the invention]

[0004] However, if purging with inert gas is unplanned under circumstances where the intake air volume is decreasing, such as when a gas turbine trips, an area where the concentration of fuel gas becomes relatively high may be created downstream of the combustor, which may lead to unintended ignition. Na This is particularly noticeable when using fuel with relatively high combustibility.

[0005] In view of the above circumstances, at least one embodiment of the present disclosure has an object to provide a gas turbine control device, a gas turbine, and a gas turbine control method that can improve the safety of the gas turbine. [Means for solving the problem]

[0006] (1) A gas turbine control device according to at least one embodiment of the present disclosure includes: A control device for a gas turbine, comprising: a purge gas flow rate control unit that controls a flow rate of purge gas for discharging fuel gas remaining inside the gas turbine to the outside of the gas turbine, The purge gas flow rate control unit controls the flow rate of the purge gas based on a parameter related to the amount of intake air from the gas turbine inlet.

[0007] (2) A gas turbine according to at least one embodiment of the present disclosure includes: A gas turbine control device having the configuration described in (1) above; a flow rate adjusting device that adjusts the flow rate of the purge gas; a turbine that is rotated by combustion gas generated by combusting the fuel gas; Equipped with.

[0008] (3) A method for controlling a gas turbine according to at least one embodiment of the present disclosure, 1. A method for controlling a gas turbine, comprising: The flow rate of purge gas for discharging fuel gas remaining inside the gas turbine to the outside of the gas turbine is controlled based on a parameter related to the amount of intake air from the gas turbine inlet. [Effects of the Invention]

[0009] At least one embodiment of the present disclosure can improve the safety of a gas turbine. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram illustrating a schematic configuration of a gas turbine according to an embodiment. [Figure 2] FIG. 2 is a functional block diagram of a control device according to some embodiments. [Figure 3] 10 is a graph illustrating an embodiment of a method for supplying a purge gas. [Figure 4]10 is a graph for explaining another embodiment of a method for supplying a purge gas. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, several embodiments of the present disclosure will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of components described as embodiments or shown in the drawings are merely illustrative examples and are not intended to limit the scope of the present disclosure. For example, expressions expressing relative or absolute arrangement such as "in a certain direction," "along a certain direction," "parallel," "orthogonal," "center," "concentric," or "coaxial" not only express such an arrangement exactly, but also express a state in which there is a relative displacement with a tolerance or an angle or distance to the extent that the same function is obtained. For example, expressions such as "identical," "equal," and "homogeneous" that indicate that something is in an equal state not only indicate a state of strict equality, but also indicate a state in which there is a tolerance or a difference to the extent that the same function is obtained. For example, expressions representing shapes such as a square shape or a cylindrical shape not only represent shapes such as a square shape or a cylindrical shape in the strict geometric sense, but also represent shapes including uneven portions, chamfered portions, etc., to the extent that the same effect can be obtained. On the other hand, the expressions "comprise," "include," "have," "includes," or "have" of one element are not exclusive expressions that exclude the presence of other elements.

[0012] (Overall configuration of gas turbine 2) An example of a gas turbine 2 including a control device 100 according to some embodiments will be described below. FIG. 1 is a diagram schematically showing a configuration of a gas turbine 2 according to one embodiment. As shown in FIG. 1, the power generation device 1 includes the gas turbine 2 and a generator 7. In FIG. 1, the configuration relating to the adjustment of the flow rate of a purge gas, which will be described later, is mainly shown, and the other configurations are omitted.

[0013] The gas turbine 2 is a power-generating gas turbine and includes a compressor 3 for generating compressed air, a combustor 4 for generating combustion gas using the compressed air and fuel, a turbine 5 configured to be rotationally driven by the combustion gas, a fuel system 20 for supplying fuel to the combustor 4, and a purge gas system 30 for supplying purge gas to a fuel pipe 26 (described later) of the fuel system 20.

[0014] The compressor 3 is connected to the turbine 5 via a rotary shaft 8A. The compressor 3 is rotationally driven by the rotational energy of the turbine 5 to generate compressed air. An inlet guide vane 6 is provided on the inlet side of the compressor 3. The amount of air flowing in is adjusted by changing the opening of the inlet guide vane 6 with an actuator 6a. The opening of the inlet guide vane 6 is controlled based on an inlet guide vane opening control command IGVCSO. The compressed air generated by the compressor 3 is supplied to the combustor 4.

[0015] Compressed air generated by the compressor 3 and fuel are supplied to the combustor 4, and the fuel is combusted to generate combustion gas, which is the working fluid for the turbine 5. The flow rate of fuel supplied to the combustor 4 is adjusted by a fuel flow control valve 23, the opening of which is adjusted in accordance with a fuel flow command. The combustion gas is sent from the combustor 4 to the turbine 5 in the downstream stage. The fuel flow rate control valve 23 is controlled by a control device 100 according to some embodiments, as will be described later.

[0016] The turbine 5 is driven by the combustion gas generated in the combustor 4. The turbine 5 is connected to the generator 7 by a rotary shaft 8B. The generator 7 is configured to generate electricity using the rotational energy of the turbine 5.

[0017] (Fuel system 20) In the gas turbine 2 according to one embodiment, the fuel system 20 is configured to supply gaseous fuel (fuel gas) as fuel. The fuel system 20 according to one embodiment includes a shutoff valve 21 for shutting off the supply of fuel gas to be supplied to the combustor 4, a pressure control valve 22 arranged downstream of the shutoff valve 21 for adjusting the pressure of the fuel gas to be supplied to the combustor 4, and a plurality of fuel flow rate control valves 23 arranged downstream of the pressure control valve 22 for adjusting the flow rate of the fuel gas to be supplied to the combustor 4. Note that, although the fuel system 20 according to one embodiment is illustrated as including, for example, five fuel supply systems 25 for supplying fuel gas to the combustors 4, the fuel supply system 25 may take other forms. Furthermore, although only one combustor 4 is representatively illustrated in Fig. 1, the gas turbine 2 may be configured to include a plurality of combustors 4, each of which may be provided with a respective fuel supply system 25.

[0018] In the gas turbine 2 according to one embodiment, a fuel flow rate control valve 23 is provided in each of the fuel pipes 26 branched into the fuel supply systems 25 downstream of the pressure control valve 22 . The shutoff valve 21 has an actuator (not shown) for opening and closing the shutoff valve 21 . The pressure regulating valve 22 has an actuator (not shown) for changing the set pressure of the pressure regulating valve 22 . Each fuel flow rate control valve 23 has an actuator (not shown) for adjusting the flow rate of the fuel gas flowing through the fuel flow rate control valve 23 . In the fuel system 20 according to one embodiment, the shutoff valve 21, the pressure regulating valve 22, and each fuel flow rate regulating valve 23 are controlled by a control device 100 according to some embodiments.

[0019] (Purge gas system 30) In one embodiment of the gas turbine 2, the purge gas system 30 includes a first purge gas supply system 31 for supplying purge gas to the fuel piping 26 between the shut-off valve 21 and the pressure control valve 22, and five second purge gas supply systems 32 for supplying purge gas to the fuel piping 26 downstream of the fuel flow control valve 23 in each fuel supply system 25.

[0020] In one embodiment of the purge gas system 30, the first purge gas supply system 31 is provided with a flow control valve 33 for adjusting the flow rate of the purge gas supplied to the fuel pipe 26, and each of the second purge gas supply systems 32 is provided with a flow control valve 34 for adjusting the flow rate of the purge gas supplied to the fuel pipe 26. Each of the flow rate control valves 33 and 34 has an actuator (not shown) for adjusting the flow rate of the purge gas flowing through each of the flow rate control valves 33 and 34 . Each of the flow rate control valves 33 and 34 is a flow rate control device that adjusts the purge flow rate Qp. In the purge gas system 30 according to one embodiment, the flow rate control valves 33 and 34 are controlled by a control device 100 according to some embodiments.

[0021] In the purge gas system 30 according to one embodiment, the purge gas is an inert gas such as nitrogen. In the following description, the purge gas supplied from the purge gas system 30 is assumed to be nitrogen.

[0022] (Control device 100) A control device 100 according to some embodiments includes a processor 101 that executes various types of arithmetic processing, and a memory 103 that non-temporarily or temporarily stores various types of data processed by the processor 101. The processor 101 is realized by a CPU, a GPU, an MPU, a DSP, various other arithmetic devices, or a combination thereof. The memory 103 is realized by a ROM, a RAM, a flash memory, or a combination thereof.

[0023] 2 is a functional block diagram of a control device 100 according to some embodiments. Note that in FIG. 2, only functional blocks related to adjusting the flow rate of purge gas, which will be described later, are shown, and other functional blocks are omitted. The control device 100 according to some embodiments includes a purge gas flow rate control unit 110. The purge gas flow rate control unit 110 includes a purge gas flow rate calculation unit 111 and a valve control signal output unit 112. The purge gas flow rate control unit 110, the purge gas flow rate calculation unit 111, and the valve control signal output unit 112 are functional blocks that are realized when the processor 101 executes a program stored in the memory 103. The purge gas flow rate calculation unit 111 calculates the flow rate (purge flow rate Qp) of the purge gas supplied from the purge gas system 30 to the fuel pipe 26 as will be described later. The valve control signal output unit 112 outputs a control signal to an actuator (not shown) of each flow rate adjustment valve 34 so that purging is performed at the purge flow rate Qp calculated by the purge gas flow rate calculation unit 111 . The specific processing contents in the control device 100 will be described in detail later.

[0024] (Purge with purge gas) For example, if purging with purge gas is unplanned under circumstances where the intake air volume is decreasing, such as when the gas turbine 2 is tripped, an area where the concentration of fuel gas becomes relatively high may occur downstream of the combustor 4, which may lead to unintended ignition. Na This is particularly noticeable when using fuel with relatively high combustibility.

[0025] Therefore, in the gas turbine 2 according to one embodiment, purge gas is supplied from the purge gas system 30 to the fuel pipe 26 as follows. FIG. 3 is a graph for explaining one embodiment of a method for supplying a purge gas. FIG. 4 is a graph for explaining another embodiment of the method for supplying purge gas. 3 and 4 show changes in the intake air amount Qa from the turbine inlet, the fuel supply amount Qf, and the hydrogen concentration Ch in the space downstream of the combustor 4. In the following explanation, it is assumed that the fuel gas contains a relatively large amount of hydrogen. In the following description, the intake air amount Qa from the turbine inlet will also be simply referred to as the intake air amount Qa, and the hydrogen concentration Ch in the space downstream of the combustor 4 will also be simply referred to as the hydrogen concentration Ch.

[0026] 3 and 4, the intake air amount Qa from the turbine inlet is represented by a thick dashed line, the fuel supply amount Qf is represented by a thin solid line, and the hydrogen concentration Ch is represented by a thin dashed line. Also, in the graphs of Figures 3 and 4, the hydrogen concentration at the lower explosion limit (LEL) is represented by a dashed line parallel to the horizontal axis of the graph. In the graphs of FIGS. 3 and 4, the zero point of the vertical axis is set at a position away from the horizontal axis to prevent the graph lines from overlapping with the horizontal axis.

[0027] The times t1, t2, and t3 described below are the times when events described below occur, and the length of time between the times t1, t2, and t3 is not necessarily the same in the graph of FIG. 3 and the graph of FIG. 4. In other words, even if the time t1 is the same in the graph of FIG. 3 and the graph of FIG. 4, death However, time t2 does not necessarily have to be the same time in the graph of Figure 3 and the graph of Figure 4. Time t3 does not necessarily have to be the same time in the graph of Figure 3 and the graph of Figure 4.

[0028] In the graphs of Figures 3 and 4, an example of supplying purge gas from the purge gas system 30 to the fuel piping 26 will be explained using the case where a trip occurs in the gas turbine 2 operating at the rated speed.

[0029] In the purge gas supply method according to some embodiments shown in Figures 3 and 4, if a trip occurs at time t1, the gas turbine rotation speed begins to gradually decrease from time t1 because the gas turbine rotates due to inertia. 3 and 4, the supply of fuel gas is stopped at time t1, so the fuel supply amount Qf is zero from time t1 when the trip occurs until time t2 when purging of the fuel pipe 26 with purge gas begins. Therefore, the hydrogen concentration Ch gradually decreases from time t1 to time t2.

[0030] When purging of the fuel pipe 26 by the purge gas begins at time t2, the fuel gas remaining in the fuel pipe 26 is pushed out by the purge gas and blown out from a fuel nozzle (not shown) of the combustor 4, causing the hydrogen concentration Ch to rise again. At this time, the flow rate of the fuel gas blown out from the fuel nozzle (not shown) of the combustor 4 is equal to the flow rate of the purge gas supplied from the purge gas system 30 to the fuel pipe 26 (purge flow rate Qp). Therefore, if the purge flow rate Qp is too high, the fuel gas remaining in the fuel pipe 26 may be pushed out all at once by the purge gas, and the hydrogen concentration Ch may exceed the lower explosion limit LEL.

[0031] (In the case of the purge gas supply method according to the embodiment shown in FIG. 3) Therefore, in the method of supplying purge gas according to one embodiment shown in FIG. 3, an upper limit is set on the purge flow rate Qp so that the hydrogen concentration Ch does not exceed a reference concentration Cs (for example, the lower explosion limit LEL). For example, in the method of supplying purge gas according to one embodiment shown in FIG. 3, purging is performed at a constant flow rate during the purge period so that the purge flow rate Qp becomes equal to the upper limit threshold value Thu. Here, the upper threshold value Thu of the purge flow rate Qp is a value that prevents the hydrogen concentration Ch from exceeding the reference concentration Cs even when the intake air amount Qa is at its smallest during the purge period. For example, in the example shown in Figure 3, the intake air amount Qa is at its smallest during the purge period at time t3, when the purge ends.

[0032] In the method of supplying purge gas according to one embodiment shown in FIG. 3, the length of the purge period (t3-t2), i.e., the time tp required for purging, is approximately equal to the value (V / Qpa) obtained by dividing the volume V of the fuel pipe 26 to be purged by the average purge flow rate Qpa during the purge period (tp≈V / Qpa). Therefore, in the purge gas supply method according to one embodiment shown in FIG. 3, when purging is terminated at time t3, the upper threshold value Thu of the purge flow rate Qp can be calculated from the intake air amount Qa at time t3, which is calculated from the turbine speed at time t3. Then, the time tp required for purging can be calculated from the calculated upper limit threshold Thu, and the timing at which purging should be started (that is, time t2) can be determined. When calculating the intake air amount Qa at time t3, the accuracy of calculation of the intake air amount Qa at time t3 can be improved by taking into consideration the opening degree of the inlet guide vane 6.

[0033] That is, in the purge gas supply method according to one embodiment shown in Fig. 3, a purge gas flow rate calculation unit 111 of a purge gas flow rate control unit 110 calculates a purge flow rate Qp based on parameters related to the intake air amount Qa. Here, the parameters related to the intake air amount Qa include a parameter related to the gas turbine rotation speed. The parameter related to the gas turbine rotation speed may be, for example, a detection value of a rotation speed sensor 9 (see Fig. 1) that detects the gas turbine rotation speed, or may be a control value for the gas turbine rotation speed. Furthermore, the parameter related to the gas turbine rotation speed may be data on the transition of the gas turbine rotation speed after a trip, which is measured in advance or calculated in advance.

[0034] In the method for supplying purge gas according to one embodiment shown in FIG. 3, the purge gas flow rate control unit 110 of For example, when the purge gas flow rate calculation unit 111 receives a trip signal indicating that the gas turbine 2 has tripped, it determines the intake air volume Qa at the time t3 when the purge ends, as described above, from data on the change in the gas turbine rotation speed after the trip, for example. Then, the purge gas flow rate calculation unit 111 calculates the upper limit threshold value Thu of the purge flow rate Qp from the intake air amount Qa at time t3. The purge gas flow rate calculation unit 111 calculates the time tp required for purging from the determined upper limit threshold Thu, and calculates the time t2 at which purging starts. The purge gas flow rate calculation unit 111 calculates the valve opening degree of each of the flow rate adjustment valves 34 corresponding to the upper limit threshold value Thu of the purge flow rate Qp. Then, the purge gas flow rate calculation unit 111 outputs the above-mentioned valve opening degree information to the valve control signal output unit 112 at the timing of time t2.

[0035] The valve control signal output unit 112 generates and outputs a control signal for driving an actuator (not shown) of the flow rate adjustment valve 34 based on the information on the valve opening degree received from the purge gas flow rate calculation unit 111 . In response to receiving the control signal, an actuator (not shown) at each flow rate adjustment valve 34 adjusts the opening of each flow rate adjustment valve 34. As a result, purge gas is supplied to each fuel pipe at the desired purge flow rate Qp.

[0036] 3, the purge gas is supplied at a flow rate that takes into consideration the intake air amount Qa from the gas turbine inlet, and therefore it is possible to prevent the occurrence of a region where the concentration of fuel gas becomes relatively high downstream of the combustor 4. This makes it possible to prevent unintended ignition and the like, thereby improving the safety of the gas turbine 2. Furthermore, since the parameters relating to the intake air amount Qa include parameters relating to the gas turbine rotation speed, the intake air amount Qa can be calculated relatively easily.

[0037] The parameters related to the intake air amount Qa may also include a parameter related to the inlet guide vane opening. The parameter related to the inlet guide vane opening may be, for example, the opening of the inlet guide vane 6, i.e., information on the drive position of the actuator 6a, or may be an inlet guide vane opening control command IGVCSO. This improves the accuracy of calculating the intake air amount Qa.

[0038] In this way, in the purge gas supply method according to one embodiment shown in FIG. 3, the purge gas flow rate control unit 110 may control the purge flow rate Qp so that it does not exceed the upper threshold value Thu of the purge flow rate Qp, which corresponds to a parameter related to the intake air amount Qa. This controls the purge flow rate Qp so that it does not exceed the upper limit threshold value Thu, and makes it possible to prevent the occurrence of a region downstream of the combustor 4 where the concentration of fuel gas becomes relatively high.

[0039] In addition, in the purge gas supply method according to one embodiment shown in FIG. 3, the upper threshold value Thu can be set so that the hydrogen concentration Ch is less than the lower explosion limit LEL of the fuel gas even at the smallest intake air amount Qa during the purge period. This improves the reliability of preventing the occurrence of a region downstream of the combustor 4 where the concentration of fuel gas becomes relatively high.

[0040] In the method for supplying purge gas according to one embodiment shown in FIG. 3, the purge flow rate Qp may be set so that the purge flow rate Qp is constant during the purge period. That is, in the purge gas supply method according to one embodiment shown in FIG. 3, the purge gas flow rate control unit 110 may control the purge flow rate Qp so that the purge flow rate Qp is constant during the purge period. This simplifies the control content in the control device 100 that controls each flow rate adjustment valve 34 as described below, and reduces the load on the processor 101 and the like in the control device 100.

[0041] In the method of supplying purge gas according to one embodiment shown in FIG. 3, when the gas turbine 2 trips, it is preferable to control the purge flow rate Qp based on the parameter related to the intake air amount Qa described above. That is, in the purge gas supply method according to one embodiment shown in FIG. 3, the purge gas flow rate control unit 110 may start controlling the purge flow rate Qp based on the parameter related to the intake air amount Qa described above when the gas turbine 2 trips. This makes it possible to prevent the occurrence of a region where the concentration of fuel gas becomes relatively high downstream of the combustor 4 when the gas turbine 2 trips. Therefore, unintended ignition and the like can be prevented when the gas turbine 2 trips, thereby improving safety when the gas turbine 2 trips.

[0042] In the purge gas supply method according to the embodiment shown in FIG. 3, the purge flow rate Qp may vary during the purge period within a range not exceeding the upper threshold value Thu of the purge gas flow rate.

[0043] After the purge period ends, that is, after time t3, fuel gas is no longer blown out from the fuel nozzle (not shown) of the combustor 4, so the hydrogen concentration Ch gradually decreases.

[0044] (In the case of the purge gas supply method according to another embodiment shown in FIG. 4) In the method for supplying purge gas according to another embodiment shown in FIG. do Intake volume Q a 4, the purge flow rate Qp is increased or decreased in accordance with the increase or decrease in the intake air amount Qa within a range in which the hydrogen concentration Ch does not exceed the reference concentration Cs during the purge period. Specifically, the purge gas flow rate calculation unit 111 of the purge gas flow rate control unit 110 calculates the purge flow rate Qp based on a function fx that increases or decreases the purge flow rate Qp in accordance with an increase or decrease in the intake air amount Qa. In other words, the function fx is a function that can calculate the purge flow rate Qp in accordance with the intake air amount Qa and can calculate the purge flow rate such that the purge flow rate Qp decreases as the intake air amount Qa decreases. In the purge gas supply method according to another embodiment shown in FIG. 4, the function fx is a function that associates a parameter related to the intake air amount Qa with the flow rate of the purge gas. In the method for supplying purge gas according to another embodiment shown in FIG. 4, the parameters related to the intake amount are the same as those in the method for supplying purge gas according to the embodiment shown in FIG. The function fx is expressed, for example, as the following equation (1), where Pa is a parameter related to the intake air amount Qa. fx=f(Pa) (1)

[0045] In another embodiment of the purge gas supply method shown in FIG. 4, when the purge gas flow rate calculation unit 111 receives a trip signal indicating that the gas turbine 2 has tripped, for example, the purge gas flow rate calculation unit 111 calculates the purge flow rate Qp based on the function fx as described above. The purge gas flow rate calculation unit 111 calculates the time tp required for purging from the calculated purge flow rate Qp, and calculates the time t2 at which purging starts. The purge gas flow rate calculation unit 111 calculates the valve aperture of each of the flow rate adjustment valves 34 corresponding to the calculated purge flow rate Qp. Then, at time t2, the purge gas flow rate calculation unit 111 starts outputting the above-mentioned valve aperture information to the valve control signal output unit 112. Until time t3, the purge gas flow rate calculation unit 111 repeatedly calculates the purge flow rate Qp based on the function fx, calculates the valve aperture of each of the flow rate adjustment valves 34 corresponding to the calculated purge flow rate Qp, and outputs the calculated valve aperture information to the valve control signal output unit 112.

[0046] The valve control signal output unit 112 generates and outputs a control signal for driving an actuator (not shown) of the flow rate adjustment valve 34 based on the information on the valve opening degree received from the purge gas flow rate calculation unit 111 . In response to receiving the control signal, an actuator (not shown) at each flow rate adjustment valve 34 adjusts the opening of each flow rate adjustment valve 34. As a result, purge gas is supplied to each fuel pipe at the desired purge flow rate Qp.

[0047] In the method for supplying purge gas according to another embodiment shown in FIG. 4, the purge flow rate Qp can be set according to the intake air amount Qa. Quantity Q a to Compared to a case where the purge flow rate Qp is set regardless of the amount of fuel used, the purge can be completed relatively quickly while preventing unintended ignition and the like.

[0048] That is, in a purge gas supply method according to another embodiment shown in Fig. 4, a purge gas flow rate calculation unit 111 of a purge gas flow rate control unit 110 calculates a purge flow rate Qp based on parameters related to the intake air amount Qa. Here, the parameters related to the intake air amount Qa include a parameter related to the gas turbine rotation speed. The parameter related to the gas turbine rotation speed may be, for example, a detection value of a rotation speed sensor 9 (see Fig. 1) that detects the gas turbine rotation speed, or may be a control value for the gas turbine rotation speed. Furthermore, the parameter related to the gas turbine rotation speed may be data on the transition of the gas turbine rotation speed after a trip, which is measured in advance or calculated in advance. As a result, the purge gas is supplied at a flow rate that takes into consideration the intake air amount Qa from the gas turbine inlet, and it is possible to prevent the occurrence of an area where the concentration of fuel gas becomes relatively high downstream of the combustor 4. This makes it possible to prevent unintended ignition, etc., and improves the safety of the gas turbine 2. Furthermore, since the parameters relating to the intake air amount Qa include parameters relating to the gas turbine rotation speed, the intake air amount Qa can be calculated relatively easily.

[0049] The parameters related to the intake air amount Qa may also include a parameter related to the inlet guide vane opening. The parameter related to the inlet guide vane opening may be, for example, the opening of the inlet guide vane 6, i.e., information on the drive position of the actuator 6a, or may be an inlet guide vane opening control command IGVCSO. This improves the accuracy of calculating the intake air amount Qa.

[0050] In the method of supplying purge gas according to another embodiment shown in FIG. 4, the purge flow rate Qp may be calculated so that the concentration of fuel gas inside the gas turbine during the purge period is less than the lower explosion limit LEL of the fuel gas. This further improves the safety of the gas turbine.

[0051] In the method of supplying purge gas according to another embodiment shown in FIG. 4, when the gas turbine 2 trips, it is preferable to control the purge flow rate Qp based on the parameter related to the intake air amount Qa described above. That is, in another embodiment of the purge gas supply method shown in FIG. 4, the purge gas flow rate control unit 110 may start controlling the purge flow rate Qp based on the parameter related to the intake air amount Qa described above when the gas turbine 2 trips. This makes it possible to prevent the occurrence of a region where the concentration of fuel gas becomes relatively high downstream of the combustor 4 when the gas turbine 2 trips. Therefore, unintended ignition and the like can be prevented when the gas turbine 2 trips, thereby improving safety when the gas turbine 2 trips.

[0052] After the purge period ends, that is, after time t3, fuel gas is no longer blown out from the fuel nozzle (not shown) of the combustor 4, so the hydrogen concentration Ch gradually decreases.

[0053] The present disclosure is not limited to the above-described embodiments, but also includes modifications to the above-described embodiments and appropriate combinations of these modifications. For example, in the above explanation, the case where the gas turbine 2 operating mainly at the rated rotation speed trips has been described. However, the purge flow rate Qp may also be controlled in the same manner as described above when the gas turbine 2 trips during turndown operation or when the gas turbine 2 trips during startup.

[0054] The contents described in each of the above embodiments can be understood, for example, as follows. (1) A control device 100 for a gas turbine 2 according to at least one embodiment of the present disclosure is a control device 100 for a gas turbine 2, and includes a purge gas flow rate control unit 110 that controls a flow rate of a purge gas (purge flow rate Qp) for discharging fuel gas remaining inside the gas turbine to the outside of the gas turbine. The purge gas flow rate control unit 110 controls the flow rate of the purge gas based on a parameter related to an intake air amount Qa from an inlet of the gas turbine.

[0055] According to the above configuration (1), the purge gas is supplied at a flow rate that takes into consideration the intake air amount Qa from the gas turbine inlet, and therefore it is possible to prevent the occurrence of an area where the concentration of fuel gas becomes relatively high downstream of the combustor 4. This makes it possible to prevent unintended ignition, etc., and therefore improves the safety of the gas turbine 2.

[0056] (2) In some embodiments, in the configuration of (1) above, the purge gas flow control unit 110 may control the flow rate of the purge gas based on a function fx that associates a parameter related to the intake air volume Qa with the flow rate of the purge gas (purge flow rate Qp).

[0057] According to the configuration (2) above, the flow rate of the purge gas (purge flow rate Qp) can be set according to the intake air amount Qa. Therefore, compared to when the flow rate of the purge gas is set regardless of the intake air amount Qa, the purge can be completed relatively quickly while suppressing unintended ignition, etc.

[0058] (3) In some embodiments, in the configuration of (2) above, the purge gas flow rate control unit 110 may control the flow rate of the purge gas (purge flow rate Qp) so that the concentration of the fuel gas inside the gas turbine is less than the lower explosion limit LEL of the fuel gas during the flow period of the purge gas.

[0059] According to the above configuration (3), the safety of the gas turbine 2 can be further improved.

[0060] (4) In some embodiments, in the configuration of (1) above, the purge gas flow control unit 110 may control the flow rate of the purge gas (purge flow rate Qp) so that it does not exceed an upper threshold value Thu of the flow rate of the purge gas (purge flow rate Qp) corresponding to a parameter related to the intake air volume Qa.

[0061] According to the above configuration (4), the flow rate of the purge gas (purge flow rate Qp) is controlled so that the intake air amount Qa from the gas turbine inlet does not exceed the considered upper limit threshold value Thu, and it is possible to prevent the occurrence of a region where the concentration of fuel gas becomes relatively high downstream of the combustor 4.

[0062] (5) In some embodiments, in the configuration of (4) above, the upper limit threshold Thu may be set so that the concentration of fuel gas inside the gas turbine is less than the lower explosion limit LEL of the fuel gas even at the smallest intake air amount Qa among the intake air amounts Qa during the circulation period of the purge gas.

[0063] According to the above configuration (5), it is possible to more reliably prevent the occurrence of a region downstream of the combustor 4 where the concentration of fuel gas becomes relatively high.

[0064] (6) In some embodiments, in the configuration of (5) above, the purge gas flow rate control unit 110 may control the flow rate of the purge gas (purge flow rate Qp) so that the flow rate of the purge gas (purge flow rate Qp) is constant during the period in which the purge gas is circulating.

[0065] The above configuration (6) simplifies the control contents in the purge gas flow rate control unit 110. This reduces the load on the processor 101 and the like in the purge gas flow rate control unit 110.

[0066] (7) In some embodiments, in any of the configurations (1) to (6) above, the purge gas flow control unit 110 may start controlling the flow rate of the purge gas (purge flow rate Qp) based on a parameter related to the intake air amount Qa from the gas turbine inlet when it detects that the gas turbine 2 has tripped.

[0067] According to the configuration (7) above, when the gas turbine 2 trips, it is possible to prevent the occurrence of an area where the concentration of fuel gas becomes relatively high downstream of the combustor 4. This makes it possible to prevent unintended ignition when the gas turbine 2 trips, thereby improving safety when the gas turbine 2 trips.

[0068] (8) In some embodiments, in any of the configurations (1) to (7) above, the parameter related to the intake air amount Qa may include a parameter related to the gas turbine rotation speed.

[0069] According to the above configuration (8), the intake air amount Qa can be calculated relatively easily.

[0070] (9) In some embodiments, in the configuration of (8) above, the parameters related to the intake air amount Qa may include a parameter related to the opening degree of the inlet guide vanes.

[0071] According to the above configuration (9), the accuracy of calculating the intake air amount Qa can be improved.

[0072] (10) A gas turbine 2 according to at least one embodiment of the present disclosure includes a control device 100 for the gas turbine 2 having any of the configurations described above in (1) to (9), a flow control device (each flow control valve 34) that adjusts the flow rate of the purge gas (purge flow rate Qp), and a turbine 5 that rotates using combustion gas generated by combusting fuel gas.

[0073] According to the configuration (10) above, the gas turbine 2 control device 100 having any of the configurations (1) to (9) above is provided, so that it is possible to prevent the occurrence of a region where the concentration of fuel gas becomes relatively high downstream of the combustor 4. This makes it possible to prevent unintended ignition, etc., and therefore improves the safety of the gas turbine 2.

[0074] (11) A control method for a gas turbine 2 according to at least one embodiment of the present disclosure is a control method for a gas turbine 2, which controls the flow rate of purge gas (purge flow rate Qp) for discharging fuel gas remaining inside the gas turbine to the outside of the gas turbine based on a parameter related to the intake air amount Qa from the gas turbine inlet.

[0075] According to the method (11) above, the purge gas is supplied at a flow rate that takes into account the intake air amount Qa from the gas turbine inlet, and therefore it is possible to prevent the occurrence of a region where the concentration of fuel gas becomes relatively high downstream of the combustor. This makes it possible to prevent unintended ignition, etc., and improve the safety of the gas turbine 2. [Explanation of symbols]

[0076] 2. Gas turbine 3 Compressor 5 Turbine 6 Inlet guide vane 20 Fuel system 26 Fuel piping 30 Purge gas system 33,34 Flow control valve 100 control device 101 processors 103 memory 110 Purge gas flow control section 111 Purge gas flow rate calculation unit 112 Valve control signal output unit

Claims

1. A control device for a gas turbine, comprising: a purge gas flow rate control unit that controls a flow rate of purge gas, which is an inert gas used to discharge fuel gas remaining inside a fuel pipe that supplies fuel to a combustor of the gas turbine to the outside of the gas turbine, the purge gas flow rate control unit controls, based on a parameter related to an intake air amount from an inlet of the gas turbine, the flow rate of the purge gas so as not to exceed an upper limit threshold of the flow rate of the purge gas corresponding to the parameter related to the intake air amount; the upper limit threshold is set so that the concentration of the fuel gas inside the gas turbine is less than the lower explosion limit of the fuel gas even when the intake air amount during the circulation period of the purge gas is the smallest. Gas turbine control device.

2. the purge gas flow rate control unit controls the flow rate of the purge gas based on a function relating a parameter related to the intake amount and the flow rate of the purge gas. The gas turbine control device according to claim 1 .

3. the purge gas flow rate control unit controls the flow rate of the purge gas so that the concentration of the fuel gas inside the gas turbine is less than the lower explosion limit of the fuel gas during a period in which the purge gas is circulating. The gas turbine control device according to claim 2 .

4. the purge gas flow rate control unit controls the flow rate of the purge gas so that the flow rate of the purge gas is constant during a period in which the purge gas is circulated. The gas turbine control device according to claim 1 .

5. the purge gas flow rate control unit starts controlling the flow rate of the purge gas based on a parameter related to an intake air amount from an inlet of the gas turbine when detecting that the gas turbine has tripped. The gas turbine control device according to claim 1 or 2.

6. The parameters related to the intake air amount include a parameter related to the gas turbine rotation speed. The gas turbine control device according to claim 1 or 2.

7. The parameters related to the intake amount include a parameter related to the inlet guide vane opening. The gas turbine control device according to claim 6.

8. The gas turbine control device according to claim 1 or 2; a flow rate adjusting device that adjusts the flow rate of the purge gas; a turbine that is rotated by combustion gas generated by combusting the fuel gas; A gas turbine comprising:

9. 1. A method for controlling a gas turbine, comprising: controlling a flow rate of a purge gas, which is an inert gas for discharging fuel gas remaining inside a fuel pipe that supplies fuel to a combustor of the gas turbine to the outside of the gas turbine, based on a parameter related to an intake air amount from an inlet of the gas turbine so that the flow rate of the purge gas does not exceed an upper limit threshold value of the flow rate of the purge gas that corresponds to the parameter related to the intake air amount; the upper limit threshold is set so that the concentration of the fuel gas inside the gas turbine is less than the lower explosion limit of the fuel gas even when the intake air amount during the circulation period of the purge gas is the smallest. A method for controlling a gas turbine.

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