Gas fuel supply device

Abstract

The present application relates to a gaseous fuel supply device for supplying gaseous fuel to a plurality of fuel nozzles provided on a combustor of a gas turbine. This device is provided with: a block valve provided upstream of a plurality of flow rate regulating valves for regulating the flow rate of gas fuel supplied to each fuel nozzle; a shut-off valve bypass valve provided on a bypass line provided so as to bypass the shut-off valve; and a control device for controlling the upstream-side pressure of the flow regulating valve. During normal operation, the upstream-side pressure is controlled according to the supply pressure of the gaseous fuel supply source by opening the shut-off valve and closing the shut-off valve bypass valve. When the gas turbine is ignited and / or when the gas turbine is accelerated, the upstream-side pressure is controlled to be lower than the pressure during normal operation by closing the shut-off valve and opening the shut-off valve bypass valve.

Description

Technical Field

[0001] The present invention relates to a gaseous fuel supply device for supplying gaseous fuel to a burner of a gas turbine.

[0002] This application claims priority based on Japanese Patent Application No. 2022-201835 filed with the Japan Patent Office on December 19, 2022, and incorporates its content herein. Background Art

[0003] In a gas turbine, a turbine is driven by combustion gas generated by burning fuel in a burner. It is known that fuel nozzles for ejecting gaseous fuel into a combustion chamber are provided in the burner. In particular, for the purpose of reducing NOx emissions and improving combustion stability, various fuel nozzles are provided. For example, in Patent Document 1, a technique related to supply control of gaseous fuel is disclosed for a burner. In this burner, as such fuel nozzles, in addition to a main nozzle for premixed combustion and a pilot nozzle for diffusion combustion, a tophat nozzle for premixed combustion for further reducing NOx emissions is provided.

[0004] A gaseous fuel supply device for supplying gaseous fuel to a burner may be configured to be able to independently control the supply amount of gaseous fuel for each type when there are multiple types of fuel nozzles as supply destinations. For example, in the structure of Patent Document 1, in each supply system for supplying gaseous fuel to various fuel nozzles, a pressure regulating valve and a flow regulating valve are respectively provided in order from the upstream side of the flow of gaseous fuel. The pressure regulating valve has a function of keeping the pressure difference between the upstream side and the downstream side of the flow regulating valve constant. Thus, the flow regulating valve performs opening control so as to become a target opening obtained by an operation based on the flow coefficient (Cv value) of the flow regulating valve under the condition that this pressure difference is constant, whereby the flow rate adjustment of gaseous fuel in the non-throttling flow region can be performed.

[0005] In the structure of the gaseous fuel supply device disclosed in Patent Document 1, a pressure regulating valve and a flow regulating valve, which are hydraulic drive valves, are respectively provided in each supply system provided for each type of fuel nozzle. The cost of the control valve or the control oil system of the hydraulic drive valve is high. Therefore, it is possible to consider reducing the cost by using an air drive valve instead of the hydraulic drive valve. However, compared with the hydraulic drive valve, the responsiveness / positioning accuracy of the air drive valve is poor. Therefore, if an air drive valve is used for the pressure regulating valve, the pressure on the upstream side of the flow regulating valve will fluctuate, which may lead to a decrease in flow controllability.

[0006] Regarding such a problem, in Patent Document 2, the flow control valve is operated in the throttling flow region, thereby omitting the pressure control valve from each supply system provided for each type of fuel nozzle, and thus the number of valves can be reduced to lower the cost. Generally speaking, if the upstream state is fixed in a pipeline where a compressible fluid flows and the downstream pressure gradually decreases, since it is initially in the non-throttling flow region, the flow rate of the pipeline increases as the downstream pressure decreases. However, if the downstream pressure drops below a certain specified pressure, it becomes a throttling flow region where the flow rate is constant (that is, in the throttling flow region, the flow rate does not depend on the downstream pressure but only on the upstream pressure).

[0007] In addition, the throttling flow region is defined as the region where the upstream pressure Pin and the downstream pressure Pout of the flow control valve satisfy the following relationship.

[0008] Pout ≤ Pin / 2 (1)

[0009] Prior art documents

[0010] Patent documents

[0011] Patent Document 1: Japanese Patent Laid-Open No. 2007-77867

[0012] Patent Document 2: WO 2013 / 105406 Summary of the invention

[0013] Technical problem to be solved by the invention

[0014] In the above Patent Document 2, by operating the flow control valve in the throttling flow region, the target opening of the flow control valve can be calculated using the upstream pressure and the required flow rate, and a pressure control valve is not required, so the number of valves is reduced, and thus cost reduction can be achieved. The assumed condition for this structure is during normal operation when the flow rate of the gaseous fuel is sufficient. Therefore, when the gas turbine is ignited or accelerating and the flow rate of the gaseous fuel becomes relatively small, the flow coefficient (Cv value) of the flow control valve becomes smaller, and the accuracy of the flow rate control of the gaseous fuel may decrease.

[0015] As a method for solving such a problem, for example, consider the following method: The flow control valve of each supply system provided for each type of fuel nozzle is composed of a main valve and a small valve with different flow coefficients, and is switched according to the flow rate of the gaseous fuel. In this case, the main valve is used during normal operation when the flow rate of the gaseous fuel is relatively large, and the sub-valve is used during ignition or acceleration when the flow rate of the gaseous fuel is relatively small, thereby being able to appropriately ensure the flow coefficient (Cv value) of the flow control valve in each operating state. However, setting the flow control valve provided for each type of fuel nozzle to this structure still results in an increase in the number of valves.

[0016] At least one embodiment of the present invention has been completed in view of the above circumstances, and an object thereof is to provide a gas fuel supply device capable of accurately controlling the flow rate of gas fuel for various fuel nozzles during ignition or speed increase of a gas turbine with a simple structure.

[0017] Means for Solving the Technical Problem

[0018] In order to solve the above problems, a gas fuel supply device according to at least one embodiment of the present invention is for supplying gas fuel to a plurality of fuel nozzles provided on a burner of a gas turbine, and the gas fuel supply device includes:

[0019] A gas fuel supply system for supplying the gas fuel to the plurality of fuel nozzles respectively via a gas fuel supply pipeline connected to a gas fuel supply source;

[0020] A plurality of flow control valves provided on the gas fuel supply pipeline for respectively adjusting the flow rate of the gas fuel for the plurality of fuel nozzles;

[0021] A shut-off valve provided at a position on the gas fuel supply pipeline upstream of the plurality of flow control valves;

[0022] A bypass pipeline provided to bypass the shut-off valve around the gas fuel supply pipeline;

[0023] A shut-off valve bypass valve provided on the bypass pipeline; and

[0024] A control device for controlling the upstream pressure of the plurality of flow control valves in the gas fuel supply pipeline,

[0025] When the gas turbine is in a normal operating state, the control device controls the upstream pressure according to the supply pressure of the gas fuel supply source by opening the shut-off valve and closing the shut-off valve bypass valve,

[0026] In an abnormal operating state including at least one of ignition or speed increase of the gas turbine, the upstream pressure is controlled to be lower than the pressure during normal operation by closing the shut-off valve and opening the shut-off valve bypass valve.

[0027] Advantages of the Invention

[0028] According to at least one embodiment of the present invention, it is possible to provide a gas fuel supply device capable of accurately controlling the flow rate of gas fuel for various fuel nozzles during ignition or speed increase of a gas turbine with a simple structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic structural diagram of a gas turbine power plant related to an embodiment.

[0030] Figure 2 is Figure 1 a schematic structural diagram of the gas fuel supply device of

[0031] Figure 3 is a block diagram showing Figure 1 the functional structure of the control device of

[0032] Figure 4 is a flowchart showing a gas turbine control method related to an embodiment.

[0033] Figure 5 is Figure 2 a schematic structural diagram of the shut-off valve unit of

[0034] Figure 6A is a structural diagram of the shut-off valve unit related to the first reference technology.

[0035] Figure 6B is a structural diagram of the shut-off valve unit related to the first reference technology.

[0036] Figure 7 is a structural diagram of the shut-off valve unit related to the second reference technology.

[0037] Figure 8 is a schematic diagram showing Figure 5 the operating state of the shut-off valve unit in an abnormal operating state (for example, during ignition or speed increase).

[0038] Figure 9 is a schematic diagram showing Figure 5 the operating state of the shut-off valve unit in a state where an abnormality has occurred. Detailed Embodiments

[0039] Hereinafter, some embodiments of the present invention will be described with reference to the accompanying drawings. However, the structures described or shown in the drawings as embodiments are not intended to limit the scope of the present invention thereto, but are merely illustrative examples.

[0040] Figure 1 is a schematic structural diagram of a gas turbine power plant 1 related to an embodiment. The gas turbine power plant 1 includes a compressor 2, a burner 3, a turbine 4, a gas fuel supply device 5, a generator 6, and a control device 50.

[0041] The compressor 2 is structured to suck in air (atmosphere) from the outside to generate compressed air. The compressed air generated by the compressor 2 is supplied to the burner 3. The burner 3 burns by mixing the compressed air supplied from the compressor 2 and the gaseous fuel which is the fuel supplied from the gaseous fuel supply device 5, thereby generating high-temperature combustion gas. The turbine 4 is driven by receiving the supply of the combustion gas generated by the burner 3, and thus rotational driving force is output from the rotating shaft 7. The rotating shaft 7 transmits the rotational driving force output from the turbine 4 to the generator 6, and thus the generator 6 generates electricity.

[0042] The control device 50 is a structure for controlling the above-described gaseous fuel supply device 5. The details of the control device 50 will be described in detail.

[0043] Next, with reference to Figure 2 The specific structure of the gaseous fuel supply device 5 will be described. Figure 2 is Figure 1 A schematic structural diagram of the gaseous fuel supply device 5. The gaseous fuel supply device 5 is a structure for supplying gaseous fuel as fuel to the burner 3.

[0044] The gaseous fuel supply device 5 is configured to be able to supply gaseous fuel to the fuel nozzles provided in the burner 3. The burner 3 may be provided with a variety of fuel nozzles. In the present embodiment, the burner 3 includes: a first main nozzle 11M1 and a second main nozzle 11M2 for premixed combustion aimed at reducing NOx, a pilot nozzle 11P for diffusion combustion aimed at stabilizing combustion, etc., and a top hat nozzle 11T which is a fuel nozzle for premixed combustion aimed at further reducing NOx as fuel nozzles. As the structure of the burner 3 having such various fuel nozzles, for example, a well-known structure such as the structure shown in Japanese Patent Application Laid-Open No. 2007-77867 can be used, and it is not particularly limited.

[0045] The gaseous fuel supply device 5 includes a common system 10C, a first main fuel supply system 10M1, a second main fuel supply system 10M2, a pilot fuel supply system 10P, and a top hat fuel supply system 10T.

[0046] The common system 10C is a system for supplying gaseous fuel to the first main fuel supply system 10M1, the second main fuel supply system 10M2, the pilot fuel supply system 10P, and the top hat fuel supply system 10T respectively, and includes a gaseous fuel supply pipe 15. One end side of the gaseous fuel supply pipe 15 is connected to a gaseous fuel supply source (not shown) which is the supply source of the gaseous fuel, and the other end side is branched and connected to the first main fuel supply system 10M1, the second main fuel supply system 10M2, the pilot fuel supply system 10P, and the top hat fuel supply system 10T.

[0047] A cut-off valve unit 22 is provided on the gas fuel supply pipeline 15. The detailed structure of the cut-off valve unit 22 will be described later. The cut-off valve unit 22 is configured to include a plurality of valves including a cut-off valve 24 to cut off the gas fuel flowing in the gas fuel supply pipeline 15. The cut-off valve 24 is provided on the gas fuel supply pipeline 15 and can switch its opening and closing state (that is, the cut-off valve 24 is a valve whose opening can be switched between two stages of "0%" or "100%").

[0048] Moreover, the cut-off valve unit 22 has a bypass pipeline 28 that bypasses the gas fuel supply pipeline 15 for the cut-off valve 24 and a cut-off valve bypass valve 26 provided on the bypass pipeline 28. The cut-off valve bypass valve 26 is a valve structure whose opening can be adjusted between "0%" and "100%".

[0049] Furthermore, the cut-off valve unit 22 has a gas fuel discharge pipeline 18 that discharges the gas fuel to the outside when the gas fuel flowing in the gas fuel supply pipeline 15 is cut off by the cut-off valve 24 or the cut-off valve bypass valve 26. A ventilation valve 19 for adjusting the flow rate of the gas fuel discharged to the outside is provided on the gas fuel discharge pipeline 18.

[0050] In addition, a pressure sensor 20 for measuring the upstream pressure, i.e., the first pressure P1, of each flow rate regulating valve (the first main flow rate regulating valve 13M1, the second main flow rate regulating valve 13M2, the pilot flow rate regulating valve 13P, and the top hat flow rate regulating valve 13T) is provided at a position on the gas fuel supply pipeline 15 downstream of the cut-off valve unit 22.

[0051] The first main fuel supply system 10M1 is a system for supplying gas fuel to the first main nozzle 11M1. One end side of the first main fuel supply system 10M1 is connected to the gas fuel supply pipeline 15 of the common system 10C, and the other end side is connected to the first main manifold 12M1 for supplying gas fuel to each first main nozzle 11M1. Moreover, a first main flow rate regulating valve 13M1 for controlling the flow rate of the gas fuel supplied to the first main nozzle 11M1 is provided in the first main fuel supply system 10M1. The first main flow rate regulating valve 13M1 is a valve for regulating the flow rate of the gas fuel supplied to the first main nozzle 11M1. The first main manifold 12M1 is a structure for distributing the gas fuel supplied from the first main fuel supply system 10M1 to a plurality of first main nozzles 11M1.

[0052] The second main fuel supply system 10M2 is a system for supplying gaseous fuel to the second main nozzle 11M2. One end side of the second main fuel supply system 10M2 is connected to the gaseous fuel supply pipeline 15 of the common system 1OC, and the other end side is connected to the second main manifold 12M2 for supplying gaseous fuel to each second main nozzle 11M2. Moreover, a second main flow regulating valve 13M2 for controlling the flow rate of the gaseous fuel supplied to the second main nozzle 11M2 is provided in the second main fuel supply system 10M2. The second main flow regulating valve 13M2 is a valve for regulating the flow rate of the gaseous fuel supplied to the second main nozzle 11M2. The second main manifold 12M2 is a structure for distributing the gaseous fuel supplied from the second main fuel supply system 10M2 to a plurality of second main nozzles 11M2.

[0053] The pilot fuel supply system 10P is a system for supplying gaseous fuel to the pilot nozzle 11P. One end side of the pilot gaseous fuel supply system 10P is connected to the gaseous fuel supply pipeline 15 of the common system 10C, and the other end side is connected to the pilot manifold 12P for supplying gaseous fuel to the pilot nozzle 11P. Moreover, a pilot flow regulating valve 13P for controlling the flow rate of the gaseous fuel is provided in the pilot fuel supply system 10P. The pilot flow regulating valve 13P is a valve for regulating the flow rate of the gaseous fuel supplied to the pilot nozzle 11P. The pilot manifold 12P is a structure for distributing the gaseous fuel supplied from the pilot fuel supply system 10P to a plurality of pilot nozzles 11P.

[0054] The top hat fuel supply system 10T is a system for supplying gaseous fuel to the top hat nozzle 11T. One end side of the top hat fuel supply system 10T is connected to the gaseous fuel supply pipeline 15 of the common system 10C, and the other end side is connected to the top hat manifold 12T for supplying gaseous fuel to the top hat nozzle 11T. Moreover, a top hat flow regulating valve 13T for controlling the flow rate of the gaseous fuel is provided in the top hat fuel supply system 10T. The top hat flow regulating valve 13T is a valve for regulating the flow rate of the gaseous fuel supplied to the top hat nozzle 11T. The top hat manifold 12T is a structure for distributing the gaseous fuel supplied from the top hat fuel supply system 10T to a plurality of top hat nozzles 11T.

[0055] Next, the structure of the control device 50 for controlling the gaseous fuel supply device 5 having the above structure will be described. Figure 3 It represents Figure 1 a block diagram of the functional structure of the control device 50.

[0056] The control device 50 is constituted by, for example, a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), and a computer-readable storage medium. Moreover, a series of processes for realizing various functions are stored, as an example, in a storage medium or the like in the form of a program, and various functions are realized by the CPU reading the program into the RAM or the like and executing information processing / arithmetic processing. In addition, the program may also be applied in a manner of being pre-installed in the ROM or other storage media, or in a manner of being provided in a state stored in a computer-readable storage medium, or in a manner of being distributed via a wired or wireless communication unit. The computer-readable storage medium refers to a magnetic disk, an optical disk, a CD-ROM, a DVD-ROM, a semiconductor memory, or the like.

[0057] The control device 50 having such a hardware structure controls each valve included in the shutoff valve unit 22 according to the operating state of the gas turbine power plant 1, and thus functions to adjust the upstream pressure of each flow control valve. As a structure for realizing this function, as Figure 3 shown, the control device 50 includes an operating state determination unit 52 and a shutoff valve unit control unit 54.

[0058] The operating state determination unit 52 is a structure for determining the operating state of the gas turbine power plant 1. The operating state determination unit 52 can at least distinguish between a normal operating state and an abnormal operating state in which the flow rate of the gaseous fuel for each fuel nozzle is less than that in the normal operating state and make a determination. The abnormal operating state includes, for example, when the turbine 4 is ignited or accelerating, but may also include other operating states.

[0059] The shutoff valve unit control unit 54 is a structure for controlling the shutoff valve unit 22. The shutoff valve unit control unit 54 includes a shutoff valve control unit 54a, a shutoff valve bypass valve control unit 54b, and a vent valve control unit 54c for respectively controlling the shutoff valve 24, the shutoff valve bypass valve 26, and the vent valve 19 included in the shutoff valve unit 22.

[0060] The shutoff valve control unit 54a is a structure for controlling the shutoff valve 24 in the shutoff valve unit 22. As described above, the shutoff valve 24 is a control valve capable of switching between a fully closed state with an opening degree of 0% and a fully open state with an opening degree of 100%, and can be switched according to a control signal from the shutoff valve control unit 54a.

[0061] The block valve bypass valve control unit 54b is a structure for controlling the block valve bypass valve 26 in the block valve unit 22. As described above, the block valve bypass valve 26 is a control valve that can be adjusted between an opening degree of 0% and 100%, and adjusts the opening degree according to a control signal from the block valve bypass valve control unit 54b.

[0062] The vent valve control unit 54c is a structure for controlling the vent valve 19 in the block valve unit 22. As described above, the vent valve 19 is a control valve that can switch between a fully closed state with an opening degree of 0% and a fully open state with an opening degree of 100%, and can be switched according to a control signal from the vent valve control unit 54c.

[0063] Next, a gas turbine control method implemented by the control device 50 having the above structure will be described. Figure 4 It is a flowchart showing a gas turbine control method according to an embodiment.

[0064] First, the operation state determination unit 52 determines whether the operation state of the gas turbine power plant 1 is a normal operation state (step S1). When the operation state is a normal operation state (step S1: YES), the block valve unit control unit 54 controls the block valve 24 to an open state, and controls the block valve bypass valve 26 and the vent valve 19 to a closed state (steps S2 to S4). Thus, in the normal operation state, the gaseous fuel is supplied to each fuel nozzle via the gaseous fuel supply pipe 15.

[0065] In addition, steps S2 to S4 can be performed in any order.

[0066] At this time, the upstream pressure Pin of each flow control valve depends on the supply pressure of the gaseous fuel from a gaseous fuel supply source (not shown) located upstream of the gaseous fuel supply pipe 15. By setting the upstream pressure Pin to satisfy the condition shown in the above formula (1), the gaseous fuel passing through each flow control valve is in the throttling flow region. Therefore, in the normal operation state, the flow rate of the gaseous fuel passing through each flow control valve does not depend on the downstream pressure Pout of each flow control valve, but is calculated based on the upstream pressure Pin. As a result, in the normal operation state, the opening degree control of each flow control valve can be performed based on the flow rate of the gaseous fuel calculated based on the upstream pressure Pin.

[0067] Thus, in the normal operating state, gaseous fuel is supplied to each fuel nozzle via the gaseous fuel supply line 15 provided with the shut-off valve 24. In an abnormal operating state where the flow rate of the gaseous fuel is relatively small compared to the normal operating state, if the same supply path of the gaseous fuel as in the normal operating state is adopted, the flow coefficient (Cv value) of each flow control valve becomes small, and the accuracy of the flow control of the gaseous fuel may decrease. Therefore, when it is determined that the operating state is an abnormal operating state (step S1: No), the shut-off valve unit control section 54 controls the shut-off valve 24 and the vent valve 19 to the fully closed state, and controls the shut-off valve bypass valve 26 to the open state, and controls its opening degree within the range where the gaseous fuel passing through each flow control valve can maintain the throttling flow region (steps S5 to S7). At this time, the opening degree of the shut-off valve bypass valve 26 is controlled to make the pressure on the upstream side of each flow control valve lower than that in the normal operating state. Since the shut-off valve bypass valve 26 is a so-called small valve configured to have a smaller flow path cross-sectional area than that of the shut-off valve 24, by thus changing the path of the gaseous fuel in the shut-off valve unit 22, even in the abnormal operating state where the flow rate of the gaseous fuel is small, the gaseous fuel passing through each flow control valve can maintain the throttling flow region, and the flow coefficient of each flow control valve is appropriately ensured to obtain control stability.

[0068] In addition, steps S5 to S7 can be performed in any order.

[0069] In addition, in Figure 4 the illustrated embodiment, for the sake of easy understanding of the description, in step S1, as the determination of the operating state, only whether it is the normal operating state is determined, but the operating state determination section 52 can also independently determine whether it is an abnormal occurrence state in which some abnormality has occurred in the gas turbine power plant 1. In this case, when it is determined that the operating state is the abnormal occurrence state, by controlling the shut-off valve 24 and the shut-off valve bypass valve 26 to be closed, and controlling the vent valve 19 to be open, the gaseous fuel flowing in the gaseous fuel supply line 15 can be cut off, and the cut-off gaseous fuel can be discharged to the outside via the gaseous fuel discharge line 18.

[0070] Next, the specific structure of the shut-off valve unit 22 will be described. Figure 5 is Figure 2 a schematic structural diagram of the shut-off valve unit 22.

[0071] The shut-off valve unit 22 is configured as a unit in which the above-described shut-off valve 24, the shut-off valve bypass valve 26, and the vent valve 19 can operate in cooperation. The shut-off valve 24, the shut-off valve bypass valve 26, and the vent valve 19 are all air-driven valves that can operate by the control air supplied from the control air supply system 40. In particular, the shut-off valve 24 and the vent valve 19 are configured to be able to alternatively switch between a fully open state and a fully closed state corresponding to the presence or absence of the supplied control air. On the other hand, the shut-off valve bypass valve 26 is a control valve configured to be able to perform opening degree control based on the control air supplied from the control air supply system 40 and the control signal from the control device 50.

[0072] The control air supply system 40 has a control air main pipe 41 with one end connected to a control air supply source (not shown) and a first control air branch pipe 42, a second control air branch pipe 43, and a third control air branch pipe 44 that branch from the other end of the control air main pipe 41 and are respectively connected to the shut-off valve 24, the shut-off valve bypass valve 26, and the vent valve 19.

[0073] A first electromagnetic valve 45 that can perform an opening and closing operation by being excited according to a control signal from the control device 50 is provided on the control air main pipe 41. In the present embodiment, in particular, the first electromagnetic valve 45 is configured to be in an open state when excited and in a closed state when not excited. And a second electromagnetic valve 46 that can perform an opening and closing operation by being excited according to a control signal from the control device 50 is provided on the first control air branch pipe 42. In the present embodiment, in particular, in contrast to the above-described first electromagnetic valve 45, the second electromagnetic valve 46 is configured to be in a closed state when excited and in an open state when not excited.

[0074] Here, as a prerequisite technique for understanding the features of the shut-off valve unit 22 having such a structure, some reference techniques will be described. Figure 6A and Figure 6B is a structural diagram of the shut-off valve unit 22'-1 related to the first reference technique, Figure 7 is a structural diagram of the shut-off valve unit 22'-2 related to the second reference technique.

[0075] In addition, in these reference techniques, the same symbols are assigned to the structures corresponding to the above-described embodiment, and repeated descriptions are omitted unless otherwise specified.

[0076] First, in Figure 6A and Figure 6B shown in the first reference technique, compared with the above-described embodiment, it has a simple structure in which the shut-off valve bypass valve 26 and its surrounding structures are omitted. In this structure, in the normal operating state where no abnormality occurs, as Figure 6AAs shown, with the shut-off valve 24 in the open state and the vent valve 19 in the closed state, gaseous fuel is supplied to each flow control valve on the downstream side via the gaseous fuel supply line 15. On the other hand, in the event of an abnormality, as Figure 6B shown, with the shut-off valve 24 in the closed state and the vent valve 19 in the open state, the gaseous fuel blocked by the shut-off valve 24 is released to the outside via the vent valve 19.

[0077] Thus, in the first reference technique, the opening and closing states of the shut-off valve 24 and the vent valve 19 have a relationship of opposite actions to each other. For such a shut-off valve 24 and a vent valve 19, if it is assumed that independent control air supply systems are respectively provided, in the case where one of the control air supply systems fails to operate normally due to a solenoid valve failure or the like, the gaseous fuel will have an unexpected flow, for example, the shut-off valve 24 and the vent valve 19, which should have opposite actions, perform the same action (for example, both are in the open state or the closed state), etc., and there is a risk from the viewpoints of equipment protection and safety.

[0078] Therefore, in FIG. 6, the shut-off valve 24 and the vent valve 19 have a common control air supply system 40 and are configured to perform opposite actions with respect to the supply of control air, thereby reducing such a risk. That is, it is configured such that the shut-off valve 24 becomes open when control air is supplied, whereas the vent valve 19 becomes closed when control air is supplied. Thereby, the above-mentioned risk can be effectively suppressed, and at the same time, the opening and closing actions of the shut-off valve 24 and the vent valve 19 in the event of an abnormality can be achieved with a simple structure.

[0079] Next, in Figure 7 the second reference technique shown, on the basis of the first reference technique, a shut-off valve bypass valve 26 and its peripheral structure are added. In the second reference technique, it is configured to directly supply control air from the control air main line 41 to the shut-off valve 24, the shut-off valve bypass valve 26, and the vent valve 19. In this case, if in the event of an abnormality, it is configured such that the shut-off valve 24 and the shut-off valve bypass valve 26 and the vent valve 19 perform opposite actions to each other as in the first reference technique, then in the case where the flow rate of the gaseous fuel is small, such as during ignition or speed increase as described above, it is impossible to cope with the opening degree control of the shut-off valve bypass valve 26 that replaces the shut-off valve 24. For example, as Figure 7 shown, if control air is supplied to the shut-off valve bypass valve 26 in order to perform the opening degree control based on the shut-off valve bypass valve 26, the control air will also be supplied to the shut-off valve 24. Therefore, it is impossible to structurally perform the operation of setting the shut-off valve 24 and the vent valve 19 to the closed state while performing the opening degree control of the shut-off valve bypass valve 26.

[0080] This problem can be solved by Figure 5This is well solved by the shut-off valve unit 22 according to the present embodiment shown. In the shut-off valve unit 22, compared with the second reference technology, a second electromagnetic valve 46 is provided on the first control air branch pipe 42 connected to the shut-off valve 24. Thus, for the supply of control air, the shut-off valve 24 and the shut-off valve bypass valve 26 and the vent valve 19 act in opposite directions with respect to the control air from the common control air supply system 40, and in the case where the flow rate of gaseous fuel is small, such as during ignition or speed increase, the shut-off valve 24 can be set to the closed state, and at the same time, the opening degree control based on the shut-off valve bypass valve 26 can be achieved.

[0081] Specifically, first, Figure 5 shows the operating state of the shut-off valve unit 22 during normal operation. In this case, the first electromagnetic valve 45 is excited according to the control signal from the control device 50 and becomes the open state. Thus, control air from the control air supply source (not shown) is supplied from the control air main pipe 41 via the first control air branch pipe 42, the second control air branch pipe 43, and the third control air branch pipe 44. Here, although the second electromagnetic valve 46 is provided on the first control air branch pipe 42, the second electromagnetic valve 46 is de-excited according to the control signal from the control device 50 and becomes the open state.

[0082] And, since the second control air branch pipe 43 is directly connected to the shut-off valve bypass valve 26, by supplying control air to the shut-off valve bypass valve 26, the shut-off valve bypass valve 26 becomes a state where the opening degree is variable, and according to the control signal from the control device 50, the opening degree of the shut-off valve bypass valve 26 is controlled to 0% (i.e., the closed state). And, since the third control air branch pipe 44 is directly connected to the vent valve 19, by supplying control air to the vent valve 19, the vent valve 19 becomes the closed state.

[0083] In this way, in the normal operation state, the shut-off valve unit 22 can supply gaseous fuel via the gaseous fuel supply pipe 15 by setting the shut-off valve 24 to the open state, and on the other hand, setting the shut-off valve bypass valve 26 and the vent valve 19 to the closed state. And, the normal operation state occupies a long period compared with other states (for example, the abnormal operation state or the abnormal occurrence state) when the gas turbine power plant 1 is in operation. Therefore, by setting the second electromagnetic valve 46 in the normal operation state to the de-excited state, the risk of failure occurring in the second electromagnetic valve 46 can be effectively reduced.

[0084] Figure 8 represents Figure 5Schematic diagram of the operating state of the shut-off valve unit 22 in an abnormal operating state (e.g., during ignition or speed increase). In the abnormal operating state, the first electromagnetic valve 45 is energized according to a control signal from the control device 50 and becomes an open state. Thereby, control air from a control air supply source (not shown) is supplied via the first control air branch line 42, the second control air branch line 43, and the third control air branch line 44 from the control air main line 41. Here, a second electromagnetic valve 46 is provided on the first control air branch line 42, but the second electromagnetic valve 46 is energized according to a control signal from the control device 50 and becomes a closed state. As a result, no control air is supplied to the shut-off valve 24, and thus the shut-off valve 24 becomes a closed state.

[0085] Moreover, since the second control air branch line 43 is directly connected to the shut-off valve bypass valve 26, by supplying control air to the shut-off valve bypass valve 26, the shut-off valve bypass valve 26 becomes a state where its opening degree is variable, and its opening degree is variably controlled according to a control signal from the control device 50. And since the third control air branch line 44 is directly connected to the vent valve 19, by supplying control air to the vent valve 19, the vent valve 19 becomes a closed state.

[0086] Thus, in the abnormal operating state, in a state where both the shut-off valve 24 and the vent valve 19 are closed, the opening degree of the shut-off valve bypass valve 26, which is a control valve, can be controlled according to a control signal from the control device 50.

[0087] Figure 9 It shows Figure 5 Schematic diagram of the operating state of the shut-off valve unit 22 in a state where an abnormality has occurred. In the state where an abnormality has occurred, the first electromagnetic valve 45 is de-energized according to a control signal from the control device 50 and becomes a closed state. Thereby, the control air from the control air supply source (not shown) is cut off in the control air main line 41. As a result, no control air is supplied from the first control air branch line 42 to the shut-off valve 24, so the shut-off valve 24 becomes a closed state, and the gaseous fuel in the gaseous fuel supply line 15 is cut off.

[0088] In addition, a second electromagnetic valve 46 is provided on the first control air branch line 42, and it is configured such that control air is not supplied to the shut-off valve 24 regardless of the open / closed state of the second electromagnetic valve 46. Therefore, even when a failure occurs in the second electromagnetic valve 46, the gaseous fuel in the gaseous fuel supply line 15 can be reliably cut off, which can be said to be a safe design.

[0089] Moreover, since the control air is not supplied from the second control air branch pipe 43 to the shut-off valve bypass valve 26, the shut-off valve bypass valve 26 is in a closed state. Also, since the control air is not supplied to the vent valve 19 via the third control air branch pipe 44, the vent valve 19 is in an open state, and the gaseous fuel cut off by the shut-off valve 24 is released to the outside via the vent valve 19.

[0090] Thus, in the event of an abnormality, by closing the shut-off valve 24 and the shut-off valve bypass valve 26 to cut off the gaseous fuel to each fuel nozzle, and by opening the vent valve 19, the cut-off gaseous fuel can be released to the outside.

[0091] In addition, within the scope not departing from the gist of the present invention, the constituent elements in the above-described embodiments can be appropriately replaced with well-known constituent elements, and the above-described embodiments can be appropriately combined.

[0092] The content described in each of the above embodiments can be grasped as follows, for example.

[0093] (1) A gaseous fuel supply device according to one aspect, which supplies gaseous fuel to a plurality of fuel nozzles provided on a burner of a gas turbine, the gaseous fuel supply device comprising:

[0094] A gaseous fuel supply system for supplying the gaseous fuel to the plurality of fuel nozzles respectively via a gaseous fuel supply pipe connected to a gaseous fuel supply source;

[0095] A plurality of flow control valves provided on the gaseous fuel supply pipe for respectively adjusting the flow rate of the gaseous fuel to the plurality of fuel nozzles;

[0096] A shut-off valve provided at a position upstream of the plurality of flow control valves in the gaseous fuel supply pipe;

[0097] A bypass pipe provided to bypass the shut-off valve around the gaseous fuel supply pipe;

[0098] A shut-off valve bypass valve provided on the bypass pipe; and

[0099] A control device for controlling the upstream pressure of the plurality of flow control valves in the gaseous fuel supply pipe,

[0100] When the gas turbine is in a normal operating state, the control device controls the upstream pressure according to the supply pressure of the gaseous fuel supply source by opening the shut-off valve and closing the shut-off valve bypass valve.

[0101] In an abnormal operating state including at least one of when the gas turbine is ignited or when its speed is increased, by closing the shut-off valve and opening the bypass valve of the shut-off valve, the upstream pressure is controlled to be lower than the pressure during normal operation.

[0102] According to the method in (1) above, in the normal operating state of the gas turbine, by opening the shut-off valve and closing the bypass valve of the shut-off valve, gaseous fuel is supplied to a plurality of fuel nozzles via the shut-off valve. At this time, the upstream pressure of the flow control valve is controlled according to the supply pressure of the gaseous fuel supply source. On the other hand, in an abnormal operating state including at least one of when the gas turbine is ignited or when its speed is increased, by closing the shut-off valve and opening the bypass valve of the shut-off valve, gaseous fuel is supplied to a plurality of fuel nozzles via the bypass valve of the shut-off valve. At this time, the upstream pressure of the flow control valve is controlled to be lower than the pressure during normal operation. Thus, even in an abnormal operating state such as ignition or speed increase when the required flow rate of the gaseous fuel of the gas turbine is less than that in the normal operating state, the flow coefficient of the flow control valve can be appropriately ensured.

[0103] (2) According to the method in (1) above, in another method,

[0104] The bypass valve of the shut-off valve is a control valve capable of adjusting the opening degree.

[0105] The control device controls the opening degree of the bypass valve of the shut-off valve in the abnormal operating state to make the upstream pressure lower than that in the normal operating state.

[0106] According to the method in (2) above, even in an abnormal operating state such as ignition or speed increase when the required flow rate of the gaseous fuel of the gas turbine is less than that in the normal operating state, the flow coefficient of the flow control valve can be appropriately ensured by controlling the opening degree of the bypass valve of the shut-off valve.

[0107] (3) According to the method in (1) or (2) above, in another method,

[0108] The control device controls the upstream pressure so that the plurality of flow control valves operate in a throttling flow state.

[0109] According to the method in (3) above, the upstream pressure of the flow control valve is controlled so that the flow control valve operates in the throttling flow region. Thus, without calculating the downstream pressure of the flow control valve, the flow control of the gaseous fuel for each fuel nozzle can be performed with a simple structure.

[0110] (4) According to any one of the methods in (1) to (3) above, in another method,

[0111] The gas fuel supply system includes a plurality of gas fuel branch pipelines that branch from the downstream side of the gas fuel supply pipeline to the plurality of fuel nozzles.

[0112] The shut-off valve is provided on the gas fuel supply pipeline.

[0113] The plurality of flow regulating valves are respectively provided on the plurality of branch gas fuel supply pipelines.

[0114] According to the method in (4) above, the gas fuel from the gas fuel supply source is supplied to each fuel nozzle via a plurality of branch gas fuel supply pipelines branched from the gas fuel supply pipeline. In such a gas fuel supply system, a shut-off valve is provided on the gas fuel supply pipeline, and a plurality of flow regulating valves are respectively provided on the plurality of branch gas fuel supply pipelines.

[0115] (5) According to any one of the methods in (1) to (4) above, in another method,

[0116] It further includes:

[0117] A gas fuel discharge pipeline for discharging the gas fuel in the gas fuel supply pipeline cut off by the shut-off valve to the outside; and

[0118] A vent valve provided on the gas fuel discharge pipeline.

[0119] The shut-off valve, the shut-off valve bypass valve and the vent valve are air-driven valves that can be operated by control air supplied from a common control air supply system.

[0120] According to the method in (5) above, for example, a vent valve is provided on the gas fuel supply pipeline constituting the gas fuel supply system. This vent valve is used to discharge the gas fuel in the gas fuel supply pipeline to the outside (for example, the atmosphere) when the gas fuel flowing in the gas fuel supply pipeline is cut off by the shut-off valve in case of an abnormality. This vent valve, together with the above-mentioned shut-off valve and shut-off valve bypass valve, is configured as an air-driven valve. Compared with a hydraulic-driven valve accompanied by a hydraulic system, an air-driven valve is advantageous in terms of cost. Moreover, the shut-off valve, the shut-off valve bypass valve and the vent valve as air-driven valves can be opened and closed by control air supplied from a common air supply system. In this way, by sharing the air supply system for supplying control air to the shut-off valve, the shut-off valve bypass valve and the vent valve, the structure can be made more efficient, effectively suppressing the installation space and cost.

[0121] (6) According to the method in (5) above, in another method,

[0122] The shut-off valve and the shut-off valve bypass valve become closed states when the control air is cut off.

[0123] The vent valve becomes open when the control air is cut off.

[0124] According to the method in (6) above, when the opening and closing states of the cutoff valve bypass valve, in addition to the cutoff valve and the vent valve, are also controlled by the control air supplied from a common air supply system, in the event of a certain abnormality, by cutting off the control air, the cutoff valve and the cutoff valve bypass valve can be set to the closed state to cut off the gaseous fuel, and the vent valve can be set to the open state to discharge the cut-off gaseous fuel to the outside.

[0125] (7) According to the method in (5) or (6) above, in another method,

[0126] The air supply system includes:

[0127] A control air supply line for supplying the control air;

[0128] A plurality of control air branch lines branched from the control air supply line and respectively connected to the cutoff valve, the cutoff valve bypass valve, and the vent valve;

[0129] A first electromagnetic valve provided on the control air supply line; and

[0130] A second electromagnetic valve provided on the control air branch line connected to the cutoff valve.

[0131] Here, in an air supply system having a cutoff valve and a vent valve but not having a cutoff valve bypass valve, when a certain abnormality occurs in the gas turbine and the gaseous fuel in the gaseous fuel supply system is cut off, the cutoff valve is closed to cut off the gaseous fuel flowing in the gaseous fuel supply line. On the other hand, the cut-off gaseous fuel is discharged to the outside by opening the vent valve. At this time, if electromagnetic valves for switching the supply / cutoff of the control air to the cutoff valve and the vent valve are independently provided, in the case where any one of the electromagnetic valves fails to operate normally due to a fault or the like, the control air will flow unexpectedly, which may pose a risk from the perspective of device protection or safety. Therefore, by sharing the electromagnetic valves for supplying / cutting off the control air to the cutoff valve and the vent valve and configuring them such that the opening and closing of the cutoff valve and the vent valve for the supply / cutoff of the control air are opposite, the number of electromagnetic valves can be reduced to reduce the failure risk and cost, and at the same time, the reliability of the closing operation of the cutoff valve and the opening operation of the vent valve during an abnormality can be improved.

[0132] In the method of (7) above, by providing a first solenoid valve on the control air supply line, in the same manner as in the above reference technology, by opening and closing the first solenoid valve, when an abnormality occurs, the opening and closing of the cut-off valve and the air vent valve are made to act in the opposite manner to each other, whereby the failure risk of the solenoid valve can be effectively reduced. On the other hand, by providing a second solenoid valve on the control air branch line connected to the cut-off valve, in an abnormal operating state such as at the time of gas turbine ignition or speed increase, the cut-off valve and the air vent valve can be closed, and the opening degree of the cut-off valve bypass valve can be controlled. With this structure, the number of solenoid valves provided in the control air supply system can be suppressed, and at the same time, the opening control of the cut-off valve bypass valve in an abnormal operating state such as at the time of gas turbine ignition or speed increase can be achieved.

[0133] (8) According to the method of (7) above, in another method,

[0134] The first solenoid valve becomes an open state when excited.

[0135] The second solenoid valve becomes a closed state when excited.

[0136] According to the method of (8) above, in the normal operating state of the gas turbine, in order not to cut off the gaseous fuel, the cut-off valve is set to an open state, and the second solenoid valve becomes a non-excited state. Thus, in the normal operating state, which occupies most of the gas turbine operation, by not exciting the second solenoid valve (i.e., by reducing the excitation period of the second solenoid valve), the possibility of the second solenoid valve having a malfunction can be reduced to improve reliability.

[0137] Symbol Explanation

[0138] 1 - Gas turbine power plant, 2 - Compressor, 3 - Burner, 4 - Turbine, 5 - Gas fuel supply device, 6 - Generator, 7 - Rotating shaft, 1OC - Common system, 10M1 - First main fuel supply system, 10P - Pilot fuel supply system, 10T - Top hat fuel supply system, 11M1 - First main nozzle, 11P - Pilot nozzle, 11T - Top hat nozzle, 12M1 - First main manifold, 12P - Pilot manifold, 12T - Top hat manifold, 13M1 - First main flow control valve, 13P - Pilot flow control valve, 13T - Top hat flow control valve, 15 - Gas fuel supply pipeline, 18 - Gas fuel discharge pipeline, 19 - Vent valve, 20 - Pressure sensor, 22 - Shutoff valve unit, 24 - Shutoff valve, 26 - Shutoff valve bypass valve, 28 - Bypass pipeline, 40 - Control air supply system, 41 - Control air main pipeline, 42 - First control air branch pipeline, 43 - Second control air branch pipeline, 44 - Third control air branch pipeline, 45 - First solenoid valve, 46 - Second solenoid valve, 50 - Control device, 52 - Operating state determination unit, 54 - Shutoff valve unit control section, 54a - Shutoff valve control section, 54b - Shutoff valve bypass valve control section, 54c - Vent valve control section.

Claims

1. A gas fuel supply device for supplying gas fuel to a plurality of fuel nozzles provided on a burner of a gas turbine, the gas fuel supply device comprising: A gas fuel supply system for supplying the gas fuel to the plurality of fuel nozzles respectively via a gas fuel supply pipeline connected to a gas fuel supply source; A plurality of flow regulating valves provided on the gas fuel supply pipeline for respectively regulating the flow rate of the gas fuel for the plurality of fuel nozzles; A shut-off valve provided at a position on the gas fuel supply pipeline upstream of the plurality of flow regulating valves; A bypass pipeline provided to bypass the shut-off valve around the gas fuel supply pipeline; A shut-off valve bypass valve provided on the bypass pipeline; and A control device for controlling the upstream pressure in the gas fuel supply pipeline, The control device, when the gas turbine is in a normal operating state, controls the upstream pressure according to the supply pressure of the gas fuel supply source by opening the shut-off valve and closing the shut-off valve bypass valve, In an abnormal operating state including at least one of when the gas turbine is ignited or when its speed is increased, the upstream pressure is controlled to be lower than the pressure during normal operation by closing the shut-off valve and opening the shut-off valve bypass valve.

2. The gas fuel supply device according to claim 1, wherein, The shut-off valve bypass valve is a control valve capable of adjusting the opening degree, The control device controls the opening degree of the shut-off valve bypass valve in the abnormal operating state to make the upstream pressure lower than that in the normal operating state.

3. The gas fuel supply device according to claim 1 or 2, wherein, The control device controls the upstream pressure so that the plurality of flow regulating valves operate in a throttling flow state.

4. The gas fuel supply device according to claim 1 or 2, wherein, The gas fuel supply system includes a plurality of gas fuel branch pipelines branched from the downstream side of the gas fuel supply pipeline to the plurality of fuel nozzles, The shut-off valve is provided on the gas fuel supply pipeline, The plurality of flow regulating valves are respectively provided on the plurality of branch gas fuel supply pipelines.

5. The gas fuel supply device according to claim 1 or 2, further comprising: A gas fuel discharge pipeline for discharging the gas fuel in the gas fuel supply pipeline blocked by the shut-off valve to the outside; and A vent valve provided on the gas fuel discharge pipeline, The shut-off valve, the shut-off valve bypass valve and the vent valve are air-driven valves that can be operated by control air supplied from a common control air supply system.

6. The gas fuel supply device according to claim 5, wherein, The shut-off valve and the shut-off valve bypass valve become closed states when the control air is cut off, The vent valve becomes an open state when the control air is cut off.

7. The gas fuel supply device according to claim 6, wherein, The air supply system comprises: A control air supply pipeline for supplying the control air; A plurality of control air branch pipelines branch from the control air supply pipeline and are respectively connected to the shut-off valve, the shut-off valve bypass valve, and the ventilation valve; A first electromagnetic valve is provided on the control air supply pipeline; and A second electromagnetic valve is provided on the control air branch pipeline connected to the shut-off valve.

8. The gas fuel supply device according to claim 7, wherein the first electromagnetic valve becomes an open state when energized, the second electromagnetic valve becomes a closed state when energized.

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