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

Abstract

The present application relates to a gas turbine control device for controlling a gas turbine including a combustor capable of co-combusting a first fuel and a second fuel having a burning velocity different from that of the first fuel. The gas turbine control device controls a control parameter of the gas turbine to operate the gas turbine at a predetermined operating point. Further, operation data, in which a combustion vibration index indicating combustion vibrations in the combustor and the co-combustion ratio of the second fuel are associated with each other, is stored in a storage unit. The operation data is used for building a combustion vibration model. The control parameter is automatically corrected so that the operating point of the gas turbine is included in a non-combustion-vibration region in which the combustion vibration index calculated using the combustion vibration model is equal to or less than a first reference value.

Description

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

[0001] This application claims priority to Japanese Patent Application No. 2023-189995, filed on November 7, 2023, with the Japan Patent Office, the contents of which are incorporated herein by reference.

[0002] Gas turbines capable of driving the turbine using combustion gases generated by combusting fuel are known. Operation of gas turbines is controlled by adjusting control parameters based on the operating state of the gas turbine. However, combustion oscillations may occur depending on the operating state of the gas turbine. To avoid such combustion oscillations, for example, Patent Document 1 discloses a technique for automatically controlling control parameters, such as the fuel flow rate or air flow rate supplied to a combustor, so that the operating state of the gas turbine is set to an operating condition that does not cause combustion oscillations.

[0003] JP 2010-127163 A

[0004] In recent years, the use of fuels with different combustion speeds, such as hydrogen gas, has been considered for gas turbines. Hydrogen gas has a higher combustion speed than conventional fuels such as natural gas. Therefore, in gas turbines that can burn a mixed fuel containing hydrogen gas (mixed combustion), the length of the flame formed in the combustor is shorter than in conventional gas turbines that burn only fuels such as natural gas, as described in Patent Document 1, making combustion oscillation more likely to occur.

[0005] At least one embodiment of the present disclosure has been made in consideration of the above-described circumstances, and has an object to provide a gas turbine control device, a gas turbine control method, and a gas turbine control program that are capable of achieving a stable operating state while avoiding the occurrence of combustion oscillation in accordance with the mixing ratio of a first fuel and a second fuel having a different combustion speed, in a gas turbine that includes a combustor that can mix and burn a first fuel and a second fuel having a different combustion speed.

[0006] In order to solve the above-mentioned problems, a gas turbine control device according to at least one embodiment of the present disclosure is a gas turbine control device for controlling a gas turbine equipped with a combustor capable of mixing and burning a first fuel and a second fuel having a combustion speed different from that of the first fuel, and includes: a controller for controlling control parameters of the gas turbine so as to operate the gas turbine at a predetermined operating point; a memory unit for storing operating data correlating a combustion oscillation index indicating combustion oscillation in the combustor with a mixing ratio of the second fuel; and an automatic correction unit for automatically correcting the control parameters using a combustion oscillation model constructed based on the operating data stored in the memory unit, so that the operating point is included in a non-combustion oscillation region where the combustion oscillation index corresponding to the mixing ratio at the operating point is equal to or less than a first reference value.

[0007] In order to solve the above-mentioned problems, a gas turbine control method according to at least one embodiment of the present disclosure is a gas turbine control method for controlling a gas turbine equipped with a combustor capable of mixing and burning a first fuel and a second fuel having a combustion speed different from that of the first fuel, the method comprising: controlling control parameters of the gas turbine so as to operate the gas turbine at a predetermined operating point; and automatically correcting the control parameters using a combustion oscillation model that is stored in a storage unit and constructed based on operating data that associates a combustion oscillation index that indicates combustion oscillation in the combustor with a mixing ratio of the second fuel, so that the operating point is included in a non-combustion oscillation region in which the combustion oscillation index that corresponds to the mixing ratio at the operating point is equal to or less than a first reference value.

[0008] In order to solve the above-mentioned problems, a gas turbine control program according to at least one embodiment of the present disclosure is a gas turbine control program for controlling a gas turbine equipped with a combustor capable of mixing and burning a first fuel and a second fuel having a combustion speed different from that of the first fuel, the program being capable of executing the following steps on a computer device: controlling control parameters of the gas turbine so as to operate the gas turbine at a predetermined operating point; and automatically correcting the control parameters using a combustion oscillation model that is stored in a storage unit and constructed based on operating data that associates a combustion oscillation index that indicates combustion oscillation in the combustor with a mixing ratio of the second fuel, so that the operating point is included in a non-combustion oscillation region in which the combustion oscillation index that corresponds to the mixing ratio at the operating point is equal to or less than a first reference value.

[0009] According to at least one embodiment of the present disclosure, in a gas turbine including a combustor capable of mixing a first fuel and a second fuel having a different combustion speed, a gas turbine control device, a gas turbine control method, and a gas turbine control program can be provided that are capable of realizing a stable operating state while avoiding the occurrence of combustion oscillation in accordance with the mixing ratio of the second fuel.

[0010] FIG. 5 is a schematic configuration diagram of a gas turbine according to one embodiment. FIG. 6 is an overall configuration diagram of a gas turbine control device for controlling the gas turbine of FIG. 1. FIG. 7 is a schematic diagram showing distribution in a multidimensional virtual space of operating data stored in a storage unit of FIG. 2. FIG. 8 is an example of an operating point map created by the automatic correction unit of FIG. 2. FIG. 9 is another example of an operating point map created by the automatic correction unit of FIG. 2. FIG. 10 is a control flow diagram showing automatic correction of a control parameter calculation unit by the automatic correction unit of FIG. 2. FIG. 5 is a diagram showing a function before automatic correction by the automatic correction unit of FIG. 5. FIG. 6 is a diagram showing a function after automatic correction by the automatic correction unit of FIG. 2. FIG. 7 is an example showing automatic correction of an operating point of a gas turbine by the automatic correction unit of FIG. 2. FIG. 8 is another example showing automatic correction of an operating point of a gas turbine by the automatic correction unit of FIG. 2.

[0011] Hereinafter, several embodiments will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of the components described as embodiments or shown in the drawings are merely illustrative examples and are not intended to limit the scope of the invention.

[0012] First, the configuration of a gas turbine 1 that is a control target of a gas turbine control device according to at least one embodiment of the present disclosure will be described with reference to Fig. 1. Fig. 1 is a schematic configuration diagram of a gas turbine according to one embodiment.

[0013] The gas turbine 1 includes a compressor 3 for generating compressed air (hereinafter referred to as "combustion air A"), a combustor 2 for generating combustion gas by mixing and burning the combustion air generated by the compressor 3 with fuel, a fuel supply system 4 for supplying fuel to the combustor 2, and a turbine 6 that can be driven by the combustion gas. In the gas turbine 1 having such a configuration, the combustor 2 is supplied with the combustion air A from the compressor 3 and fuel (mixed fuel Fm, described below) supplied from the fuel supply system 4, and these are mixed and burned to generate combustion gas. This combustion gas flows into the turbine 6 and functions as a working medium for driving the turbine 6.

[0014] The fuel supply system 4 handles a mixed fuel obtained by mixing a first fuel F1 and a second fuel F2 as the fuel to be supplied to the combustor 2. The second fuel F2 is a fuel having a combustion speed different from that of the first fuel F1. In particular, in this embodiment, the second fuel F2 is a fuel having a higher combustion speed than the first fuel F1 (or a fuel having a lower calorific value per unit volume). In this embodiment, the first fuel F1 is liquefied natural gas (LNG), and the second fuel F2 is hydrogen gas.

[0015] The first fuel F1 is stored in a first fuel supply source 7 and is supplied via a first fuel supply line 8 connected to the first fuel supply source 7. A flow meter 10 is provided in the first fuel supply line 8 to detect the flow rate of the first fuel F1.

[0016] The second fuel F2 is stored in a second fuel supply source 14 and is supplied via a second fuel supply line 16 connected to the second fuel supply source 14. The second fuel supply line 16 is provided with a flow rate adjustment valve 18 for adjusting the flow rate of the second fuel F2, a shutoff valve 13 for shutting off the second fuel F2, and a flow meter 15 for detecting the flow rate of the second fuel F2.

[0017] The first fuel supply line 8 and the second fuel supply line 16 join each other at a joining point 25 provided downstream and are connected to a mixing line 22. The first fuel F1 and the second fuel F2 join at the joining point 25 to form a mixed fuel (hereinafter referred to as "mixed fuel Fm" as appropriate) and are sent via the mixing line 22. The mixing line 22 is provided with a shutoff valve 24 for shutting off the mixed fuel Fm.

[0018] The downstream side of the mixing line 22 branches into multiple lines for supplying the mixed fuel Fm to the multiple fuel injection nozzles included in the combustor 2, respectively. Specifically, the multiple fuel injection nozzles included in the combustor 2 include main fuel injection nozzles, pilot fuel injection nozzles, and top hat fuel injection nozzles. The downstream side of the mixing line 22 branches into a main fuel supply line 28a for supplying the mixed fuel Fm to the main fuel injection nozzles, a pilot fuel supply line 28b for supplying the mixed fuel Fm to the pilot fuel injection nozzles, and a top hat fuel supply line 28c for supplying the mixed fuel Fm to the top hat fuel injection nozzles. The main fuel supply line 28a, the pilot fuel supply line 28b, and the top hat fuel supply line 28c are provided with flow control valves 26a, 26b, and 26c, respectively, thereby enabling independent control of the flow rate of the mixed fuel supplied to each fuel injection nozzle.

[0019] Next, a gas turbine control device for controlling the gas turbine 1 having the above configuration will be described. Fig. 2 is a diagram showing the overall configuration of the gas turbine control device for controlling the gas turbine 1 of Fig. 1.

[0020] As shown in FIG. 2 , the gas turbine control system includes a main control device 100 and an external control device 200. The main control device 100 is located near the gas turbine 1 (e.g., at the site where the gas turbine 1 is installed) and is capable of transmitting and receiving various signals (e.g., operation data and control signals, described below) to and from the gas turbine 1. The external control device 200 is an external computing device that is capable of transmitting and receiving various signals to and from the main control device 100. By implementing some of the functions of the gas turbine control system using the external control device 200 in this manner, the storage capacity and computing capacity of the main control device 100 located near the gas turbine 1 can be reduced. Therefore, as described below, even if data such as the hydrogen-mixed combustion ratio Rfh is added as operating data to be calculated, data processing in the main control device 100, which directly controls the gas turbine 1, can be simplified. The external control device 200 may be operated from a remote terminal via a network.

[0021] The main control device 100 is a computer including, for example, a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), etc. The main control device 100 includes an operating data acquisition unit 110, a control parameter calculation unit 120, and a control unit 130 as components for realizing various functions by the processor (CPU) executing programs stored in the memory (RAM or ROM).

[0022] The operating data acquisition unit 110 is configured to acquire operating data of the gas turbine 1. The operating data acquired by the operating data acquisition unit 110 includes at least the hydrogen mixing ratio Rfh. This hydrogen mixing ratio Rfh is obtained as the ratio Rfh of the flow rate of the second fuel F2 to the total fuel flow rate, using the flow rate of the first fuel F1 measured by a flow meter 10 installed in the first fuel supply line 8 and the flow rate of the second fuel F2 measured by a flow meter 15 installed in the second fuel supply line 16.

[0023] Furthermore, the operating data acquired by the operating data acquisition unit 110 may include, in addition to the hydrogen mixed-fuel ratio Rfh described above, data necessary for controlling the operation of the gas turbine 1. In this embodiment, some examples of other data included in the operating data include the combustion load factor CLCSO related to the fuel supply system 4, the lower heating value LHV measured by a calorimetry in the fuel supply system 4 and related to the combustion state, and the gas turbine inlet temperature T1C (GT inlet Temperature) detectable by a temperature sensor 32 installed at the inlet of the gas turbine. Note that T1C may be the temperature of the atmosphere or the like, and is not limited to that measured by the gas turbine inlet temperature sensor 32.

[0024] The control parameter calculation unit 120 is configured to calculate control parameters for controlling the gas turbine 1 based on the operating data acquired by the operating data acquisition unit 110. The control parameter calculation unit 120 has functions (see functions FX1 and FX2 in FIG. 5 ) that indicate the relationship between the operating data and the control parameters, and calculates the corresponding control parameters by inputting the operating data acquired by the operating data acquisition unit 110 into the functions.

[0025] The control unit 130 is configured to control the gas turbine 1 based on the control parameters calculated by the control parameter calculation unit 120. For example, the control unit 130 inputs the deviation between the control parameter calculated by the control parameter calculation unit 120 and a target value corresponding to the control parameter to a PI controller, thereby outputting a corresponding control command. The control command output from the control unit 130 is transmitted to the gas turbine 1, thereby executing control of the gas turbine 1.

[0026] The external control device 200 is a computer including, for example, a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), etc. The external control device 200 includes an operating data collection unit 210, a storage unit 220, a combustion oscillation model construction unit 230, a combustion oscillation index calculation unit 240, an automatic correction unit 250, an operation restriction index calculation unit 260, and a monitoring unit 270 as components for realizing various functions by the processor (CPU) executing programs stored in the memory (RAM or ROM).

[0027] The operating data collection unit 210 is configured to collect operating data to be stored in the memory unit 220. In this embodiment, the operating data collection unit 210 collects operating data by receiving the operating data acquired by the operating data acquisition unit 110 of the main control device 100. The operating data collection unit 210 sequentially collects operating data, and the collected operating data is promptly transmitted to the memory unit 220, the combustion oscillation model construction unit 230, the combustion oscillation index calculation unit 240, and the operation restriction index calculation unit 260, respectively, as needed.

[0028] The storage unit 220 is configured to readably store the operating data collected by the operating data collection unit 210 (for example, a storage unit such as a database). The operating data stored in the storage unit 220 is used by the combustion oscillation model construction unit 230 to construct the combustion oscillation model M, as will be described later. The storage unit 220 has an upper limit to its storage capacity. Therefore, the storage unit 220 stores the operating data collected by the operating data collection unit 210 so that operating data suitable for constructing the combustion oscillation model M is accumulated within the storage capacity.

[0029] Here, Fig. 3 is a schematic diagram showing the distribution in a multidimensional virtual space VS of the operating data stored in the storage unit 220 of Fig. 2. The multidimensional virtual space VS of Fig. 3 is shown as an n-dimensional virtual space defined by spatial axes corresponding to n physical quantities that are at least a part of the operating data (for convenience of explanation, the multidimensional virtual space VS of Fig. 3 is shown as a three-dimensional space that can be represented on paper, and an example is shown in which the combustion load factor CLCSO, the gas turbine inlet temperature T1C, and the hydrogen mixing ratio Rfh are selected as the three spatial axes. Other spatial axes may also be the pilot fuel ratio PL, the top hat fuel ratio TH, etc.).

[0030] The operating data stored in the storage unit 220 is used for regression analysis when constructing the combustion oscillation model M, as described below. Therefore, if the operating data stored in the storage unit 220 is unevenly distributed in some unit spaces IS in the multidimensional virtual space VS, the accuracy of the combustion oscillation model M obtained by regression analysis may be reduced (i.e., a combustion oscillation model M with low prediction accuracy of combustion oscillation may be constructed in an operating region corresponding to a unit space IS with insufficient operating data). Furthermore, depending on the operating pattern of the gas turbine 1, a large amount of similar operating data acquired at operating points with long operating times may be collected. In regression analysis, using operating data corresponding to various operating points likely contributes to improving the accuracy of the combustion oscillation model. Therefore, such a large amount of similar operating data makes little contribution to improving the accuracy of the combustion oscillation model M obtained by regression analysis and may unnecessarily consume the storage capacity of the storage unit 220.

[0031] In view of this problem, the storage unit 220 may store driving data so that the number of data included in the unit space IS of the multidimensional virtual space VS is equal to or less than a predetermined value. For example, when new driving data is collected, if a predetermined value of driving data is already stored in the unit space IS corresponding to the driving data, one of the driving data is updated (overwritten) with the new driving data. This prevents the driving data stored in the storage unit 220 from being concentrated in a specific unit space IS, thereby enabling efficient collection of driving data corresponding to various driving points.

[0032] Returning to Fig. 2 again, the combustion oscillation model construction unit 230 is configured to construct the combustion oscillation model M using the operating data stored in the storage unit 220. The combustion oscillation model construction unit 230 constructs the combustion oscillation model M, for example, by regression analysis of the operating data stored in the storage unit 220. In this regression analysis, at least the hydrogen mixing ratio Rfh, among various data included in the operating data, is included as an explanatory variable, and the combustion oscillation index Ib is set as a response variable. When predetermined operating data including the hydrogen mixing ratio Rfh is input from the operating data collection unit 210, the combustion oscillation model M constructed in this manner outputs a combustion oscillation index Ib that indicates the possibility of combustion oscillation occurring at an operating point corresponding to the operating data.

[0033] The combustion oscillation index calculation unit 240 is configured to calculate a combustion oscillation index Ib corresponding to operating data by using the combustion oscillation model M. The combustion oscillation index calculation unit 240 inputs the operating data acquired by the operating data acquisition unit 110 to the combustion oscillation model M, thereby calculating a combustion oscillation index Ib corresponding to the operating point at which the operating data was acquired.

[0034] The automatic correction unit 250 is configured to automatically correct the control parameters calculated by the control parameter calculation unit 120 using the combustion oscillation model M constructed by the combustion oscillation model construction unit 230 so that the combustion oscillation index Ib calculated by the combustion oscillation index calculation unit 240 becomes equal to or less than the first reference value Ibref.

[0035] The automatic correction unit 250 may create an operating point map based on the combustion oscillation model M, and perform automatic correction based on the operating point map. To create the operating point map, the combustion oscillation index calculation unit 240 repeatedly inputs the operating data stored in the storage unit 220 into the combustion oscillation model M and calculates the combustion oscillation index Ib. Then, by distinguishing between an operating point at which the combustion oscillation index Ib is equal to or smaller than the first reference value Ibref and an operating point at which the combustion oscillation index Ib is greater than the first reference value Ibref, it is possible to create an operating point map that indicates an operable range of the gas turbine 1.

[0036] 4A and 4B show several examples of operating point maps created by the automatic correction unit 250 of FIG. 2. In FIGS. 4A and 4B, the operating point maps are created as a space where the operating point of the gas turbine 1 can be defined by the pilot fuel ratio PL and the top hat fuel ratio TH, which are physical quantities included in the operating parameters. When the combustion load factor CLCSO is 50% and 100%, respectively, a non-combustion oscillation region C1 where the combustion oscillation index Ib is equal to or less than the first reference value Ibref and a combustion oscillation region C2 where the combustion oscillation index Ib is greater than the first reference value Ibref are shown. In particular, FIGS. 4A and 4B show that the non-combustion oscillation region C1 and the combustion oscillation region C2 are suitably determined for each hydrogen mixing ratio Rfh and each combustion load factor CLCSO. The automatic correction unit 250 automatically corrects the control parameters based on the operating point map so that the operating point of the gas turbine 1 falls within the non-combustion oscillation region C1, thereby making it possible to suitably avoid combustion oscillation even when the hydrogen mixing ratio Rfh changes.

[0037] As described above, the operating point map is basically created based on the combustion oscillation index Ib calculated by the combustion oscillation model M, but it may also be created based on past operational performance of the gas turbine 1. In this case, the non-combustion oscillation region C1 may be specified so as to avoid operating points where combustion oscillation occurred in the past. In other words, if there is an operating point where combustion oscillation actually occurred in past gas turbine control, the operating point map is corrected so that the operating point is included in the non-combustion oscillation region C1. This makes it possible to perform automatic correction based on the non-combustion oscillation region C1 that reflects past performance, thereby effectively improving the control accuracy of the gas turbine 1.

[0038] The automatic correction by the automatic correction unit 250 will now be described in detail with reference to Fig. 5. Fig. 5 is a control flow diagram showing the automatic correction of the control parameter calculation unit 120 by the automatic correction unit 250 of Fig. 2.

[0039] As shown in FIG. 5 , at least one of the combustion load factor CLCSO, the lower heating value LHV, the gas turbine inlet temperature T1C, and the hydrogen-mixed combustion ratio Rfh acquired by the operating data acquisition unit 110 is input to the control parameter calculation unit 120 as a first operating parameter. A function FX1 defines the relationship between the first operating parameter and the basic control parameter, and outputs the basic control parameter corresponding to the input first operating parameter. The first operating parameter is also input to a function FX2. The function FX2 defines the relationship between the first operating parameter and a first correction coefficient k1 for correcting the basic control parameter, and outputs the first correction coefficient k1 corresponding to the input first operating parameter.

[0040] Furthermore, at least one of the combustion load factor CLCSO, the lower heating value LHV, the gas turbine inlet temperature T1C, and the hydrogen mixed-fuel ratio Rfh acquired by the operating data acquisition unit 110 is input to the control parameter calculation unit 120 as a second operating parameter. The function FX3 is a function that defines the relationship between the second operating parameter and a second correction coefficient k2 for correcting the basic control parameter, and outputs the second correction coefficient k2 corresponding to the input second operating parameter. The second correction coefficient k2 output from the function FX3, together with the first correction coefficient k1 output from the function FX2, is used to correct the basic control parameter output from the function FX1, and the corrected basic control parameter is output from the control parameter calculation unit 120 as the control parameter.

[0041] Preferably, the combustion load factor CLCSO may be used as the first operating parameter, the hydrogen mixed combustion ratio Rfh may be used as the second operating parameter, and the fuel flow rate ratio (PL, TH) to each nozzle (described later) may be calculated as the control parameter. The fuel flow rate ratio, which is the control parameter calculated in this manner, may be sent to the control unit 130, which adjusts the fuel flow rate to each nozzle. Note that it is desirable that the second operating parameter is an input value different from the first operating parameter. In addition, the example shown in FIG. 5 illustrates a case where the control parameter calculation unit 120 has functions FX1 to FX3 to which two types of operating parameters are input. However, three or more types of operating parameters may be input to the control parameter calculation unit 120. In this case, the control parameter calculation unit 120 may have more functions FX depending on the number of operating parameters.

[0042] 6A and 6B are diagrams showing the function FX2 before and after automatic correction by the automatic correction unit 250 in Fig. 5. Fig. 6A shows the original function FX2 when automatic correction by the automatic correction unit 250 is not performed (i.e., when the correction command from the automatic correction unit 250 is zero). Note that Fig. 6A shows the characteristic of the first correction coefficient k1 with respect to an arbitrary first operating parameter as a specific function FX2, but the shape of this function FX2 is merely an example and is not limited thereto.

[0043] 6B shows the function FX2′ corrected by the correction command from the automatic correction unit 250. In this example, since the combustion oscillation index Ib becomes larger than the first reference value Ibref at some operating points of the original function FX2, the function FX2′ is corrected so as to avoid those operating points.

[0044] In this embodiment, the target of automatic correction by the automatic correction unit 250 is the function FX2 of the control parameter calculation unit 120, but at least one of the functions FX1 and FX3 may also be the target of automatic correction.

[0045] 7A shows an example of automatic correction of the operating point of the gas turbine 1 by the automatic correction unit 250 of Fig. 2. The operating point of the gas turbine 1 is defined based on at least one physical quantity included in the operational data, but Fig. 7A shows a case where the operating point is identified by the pilot fuel ratio (the ratio of the amount of fuel supplied to the pilot fuel injection nozzle out of the total amount of fuel supplied), the top hat fuel ratio TH (the ratio of the amount of fuel supplied to the top hat fuel injection nozzle out of the total amount of fuel supplied), and the combustion load factor CLCSO, which are all physical quantities included in the operational data.

[0046] 7A shows a non-combustion oscillation region C1 where the combustion oscillation index Ib calculated using the combustion oscillation model M is equal to or less than the first reference value Ibref, and a combustion oscillation region C2 where the combustion oscillation index Ib is greater than the first reference value Ibref. For example, when the operating state of the gas turbine 1 is at an operating point A1, the combustion oscillation index calculation unit 240 calculates the combustion oscillation index Ib as a value greater than the first reference value Ibref. In this case, the automatic correction unit 250 automatically corrects the control parameters by sending a correction command to the control parameter calculation unit 120 so that the combustion oscillation index Ib is equal to or less than the first reference value Ibref. As a result, the operating point A1 in the combustion oscillation region moves to an operating point A2 in the non-combustion oscillation region, and automatic control that avoids combustion oscillation is realized.

[0047] The operation restriction index calculation unit 260 is configured to calculate the operation restriction index. The operation restriction index is an index related to the protection and stable combustion of the gas turbine 1, and is an index for determining whether the combustion oscillation index Ib used when automatically controlling the operating point as described above is appropriate as an index for automatically controlling the operating point of the gas turbine 1 to a safe operating point (i.e., an index for determining whether the combustion oscillation index Ib described above is appropriate as an index for automatically controlling the gas turbine 1 to a safe operating point). Therefore, the operation restriction index is an index excluding the combustion oscillation index Ib that is the object of determination (i.e., the operation restriction index does not include the combustion oscillation index Ib itself). Specifically, the operation restriction index includes a flashback restriction index that quantitatively indicates the possibility of flashback occurrence in the gas turbine 1, a misfire restriction index that quantitatively indicates the possibility of misfire, and the like. The automatic correction unit 250 may automatically correct these operation restriction indexes so that they are equal to or less than the second reference value Ib.

[0048] In the following description, a case will be described in which the flashback restriction index Fb is used as an example of an operation restriction index calculated by the operation restriction index calculation unit 260. The operation restriction index calculation unit 260 is configured to calculate the flashback restriction index Fb corresponding to the operation data of the gas turbine 1 as an example of an operation restriction index. The operation restriction index calculation unit 260 prepares in advance a function that defines the relationship between the operation data and the flashback restriction index Fb by an experimental, theoretical, or simulation technique, and inputs the operation data acquired by the operation data acquisition unit 110 to the function to calculate the flashback restriction index Fb corresponding to the operating point at which the operation data was acquired.

[0049] For example, the flashback restriction index Fb can be calculated by correcting it to match the hydrogen mixing ratio Rfh. Specifically, when the hydrogen mixing ratio Rfh increases, the flashback restriction index Fb is calculated after correcting it so that the stable combustion region narrows. Similarly, other operational restriction indexes, such as the metal temperature restriction index and the misfire restriction index, can also be corrected to match the hydrogen mixing ratio Rfh.

[0050] 7B is another example showing automatic correction of the operating point of the gas turbine 1 by the automatic correction unit 250 of FIG. 2. In FIG. 7B, in addition to the non-combustion oscillation region C1 and combustion oscillation region C2 similar to those in FIG. 7A, a non-flashback region C3 in which the flashback restriction index Fb calculated by the operation restriction index calculation unit 260 is equal to or less than the second reference value Fbref, and a flashback region C4 in which the flashback restriction index Fb is greater than the second reference value Fbref are shown. In FIG. 7B, similar to FIG. 7A, automatic correction is performed when moving an operating point A3 in the combustion oscillation region C2 to an operating point A4 in the non-combustion oscillation region C1 so as not to enter the flashback region C4. This makes it possible to perform automatic correction that avoids the combustion oscillation described above and suitably reduces the risk of flashback occurrence.

[0051] Returning to Fig. 2 again, the monitoring unit 270 is configured to monitor the control parameters calculated by the control parameter calculation unit 120. As described above, the control parameter calculation unit 120 of the main control unit 100 calculates automatically corrected control parameters based on a correction command from the automatic correction unit 250 of the external control unit 200. The automatically corrected control parameters are transmitted from the main control unit 100 to the external control unit 200, and are monitored by the monitoring unit 270. In this way, by monitoring the automatically corrected control parameters on the external control unit 200 side, a high degree of reliability in gas turbine control can be ensured.

[0052] As described above, according to each of the above embodiments, in a gas turbine 1 capable of mixing and burning a first fuel F1 such as natural gas with a second fuel F2 such as hydrogen gas, which has a high combustion rate, the control parameters calculated based on the operating data are automatically corrected, thereby preventing combustion oscillation and flashback, and thereby making it possible to maintain a stable operating state of the gas turbine 1.

[0053] In addition, within the scope of the present disclosure, the components in the above-described embodiments may be replaced with well-known components as appropriate, and the above-described embodiments may be combined as appropriate.

[0054] For example, in the embodiment described above with reference to Figure 7, control is described to change the operating point A so that it does not enter the flashback region. However, similar control can be performed when the mixed-fuel ratio is 0 or 100%, i.e., when the fuel is exclusively burned. Even in this case, reliable operation can be ensured. Furthermore, the external control device 200 can similarly receive and monitor data from the main control device 100 even when the mixed-fuel ratio is 0 or 100%, thereby ensuring high reliability in gas turbine control.

[0055] Furthermore, regarding the physical quantities included in the operational data, although the above embodiment has exemplified the pilot fuel ratio PL and the top hat fuel ratio TH as physical quantities related to the fuel flow rate ratio, the present invention is not limited thereto. For example, in the case of a combustor equipped with secondary fuel nozzles that supply fuel to a downstream position of the main fuel injection nozzles and pilot fuel injection nozzles, which are primary fuel nozzles, as disclosed in International Publication No. 2023 / 218777, the ratio of the fuel supply amount to the secondary fuel nozzles out of the total fuel supply amount can be included as a physical quantity constituting the operational data. This ratio can be selected as a spatial axis defining the multidimensional virtual space VS in FIG. 3 or can be set as an explanatory variable when performing an analysis (e.g., regression analysis) using a combustion oscillation index as an objective function. Note that, when a combustor that burns a single type of fuel is to be controlled, the mixed-fuel ratio may not be included in the physical quantities constituting the operational data. In such a case, combustion oscillation may be avoided based on physical quantities such as the ratio of the fuel supply amounts to the various fuel nozzles described above, instead of the mixed-fuel ratio.

[0056] The contents described in each of the above embodiments can be understood, for example, as follows.

[0057] (1) A gas turbine control device according to one aspect is a gas turbine control device for controlling a gas turbine equipped with a combustor capable of mixing and burning a first fuel and a second fuel having a combustion speed different from that of the first fuel, the gas turbine control device comprising: a controller for controlling control parameters of the gas turbine so as to operate the gas turbine at a predetermined operating point; a memory unit for storing operating data correlating a combustion oscillation index indicating combustion oscillation in the combustor with a mixing ratio of the second fuel; and an automatic correction unit for automatically correcting the control parameters using a combustion oscillation model constructed based on the operating data stored in the memory unit so as to include the operating point in a non-combustion oscillation region where the combustion oscillation index corresponding to the mixing ratio at the operating point is equal to or less than a first reference value.

[0058] According to the above aspect (1), the control parameters of the gas turbine are automatically corrected using a combustion oscillation model so that the operating point of the gas turbine falls within a non-combustion oscillation region where a combustion oscillation index corresponding to the combustion mixture ratio is equal to or less than a first reference value. In particular, the construction of the combustion oscillation model used by the automatic correction unit and the calculation of the control parameters are performed based on the combustion mixture ratio of the second fuel, so that the control parameters are automatically corrected according to the combustion mixture ratio of the second fuel. As a result, even if the operating point of the gas turbine changes due to a change in the combustion mixture ratio of the second fuel, the operating point of the gas turbine is automatically controlled to fall within the non-combustion oscillation region, so that combustion oscillation can be avoided according to the combustion mixture ratio of the second fuel and the stability of the operating state of the gas turbine can be favorably maintained.

[0059] (2) In another aspect, in the aspect (1), the combustion oscillation model constructing unit is further provided for constructing the combustion oscillation model by analyzing the operating data using at least the mixed-fuel ratio as an explanatory variable and the combustion oscillation index as an objective function.

[0060] According to the above aspect (2), by performing an analysis (e.g., regression analysis) on the operating data stored in the storage unit using the mixed-fuel ratio as an explanatory variable and the combustion oscillation index as an objective function, it is possible to suitably obtain a combustion oscillation model for estimating the combustion oscillation index at each operating point.

[0061] (3) In another aspect, in the aspect (1) or (2), the automatic correction unit corrects the control parameter so as to change the operating point to a region where an operational restriction index in the combustor, which is variably corrected with respect to the mixed-fuel ratio, is equal to or less than a second reference value.

[0062] According to the above aspect (3), the control parameters are automatically corrected so that the operating point is changed so that the operational restriction index, which quantitatively indicates the occurrence probability of an event that may impose restrictions on the operation of a combustor included in the gas turbine, becomes equal to or less than a preset second reference value. This makes it possible to automatically control the gas turbine so as to avoid a state in which operational restrictions are required by suppressing the occurrence probability of an event that may impose restrictions on the operation of the combustor to equal to or less than the second reference value.

[0063] (4) In another aspect, in the aspect (3), the operational restriction indicator is a restriction indicator that indicates the possibility of flashback or misfire occurring.

[0064] According to the above aspect (4), the control parameters of the gas turbine are automatically corrected so that the operating point of the gas turbine is included in the non-restricted region where the restriction index, which is an operational restriction index, is equal to or less than the second reference value. As a result, even if the operating point of the gas turbine changes due to a change in the mixing ratio of the second fuel, the gas turbine is automatically controlled so that the operating point is within the non-restricted region, thereby avoiding not only combustion oscillation but also flashback or misfire, and making it possible to preferably maintain the stability of the operating state of the gas turbine.

[0065] (5) In another aspect, in any one of the above aspects (1) to (4), the non-combustion oscillation region is identified so as to avoid an operating point where the combustion oscillation has occurred in the past.

[0066] According to the above aspect (5), the non-combustion oscillation region is basically identified using the combustion oscillation model as described above, but if there is an operating point where combustion oscillation actually occurred in past gas turbine control, that operating point is reflected in the non-combustion oscillation region. This makes it possible to perform automatic correction based on the non-combustion oscillation region that reflects past performance, thereby effectively improving the control accuracy of the gas turbine.

[0067] (6) In another aspect, in any one of the above aspects (1) to (5), the automatic correction unit corrects the control parameter by modifying a function for calculating the control parameter based on the operating data.

[0068] According to the above aspect (6), the control parameters can be automatically corrected by modifying the function for calculating the control parameters based on the operating data.

[0069] (7) In another aspect, in any one of the above aspects (1) to (6), the automatic correction unit determines a correction amount for the control parameter based on a load factor of the gas turbine and the mixed combustion ratio.

[0070] According to the above aspect (7), the amount of correction to the control parameters by the automatic correction unit is calculated based on the operating data, thereby realizing stable gas turbine operation while avoiding combustion oscillation. In particular, since the operating data for calculating the amount of correction includes the fuel-mixture ratio, it is possible to preferably maintain a stable gas turbine operating state while avoiding combustion oscillation even when the fuel-mixture ratio changes.

[0071] (8) In another aspect, in any one of the above aspects (1) to (7), the automatic correction unit is configured as an external calculation device capable of communicating with the control unit.

[0072] According to the above aspect (8), the automatic correction unit that automatically corrects the control parameters to avoid combustion oscillation is configured as an external computing device capable of communicating with the control unit that controls the gas turbine using the control parameters. In the control unit, the relationship between the gas turbine operating parameters and the control parameters is defined by a predetermined function implemented, for example, as a PLC, and the control parameters corresponding to the operating parameters are calculated by referring to the function. If there is a risk of combustion oscillation occurring due to control using control parameters calculated based on such a function, the automatic correction unit configured as an external computing device can correct the control parameters by modifying the function, thereby effectively avoiding combustion oscillation. In this way, by implementing some of the functions of the gas turbine control device using an external computing device located remotely from the gas turbine, the memory capacity and computing capacity of the main unit located near the gas turbine can be reduced. Therefore, even if data such as the mixed-fuel ratio is added as operating data to be calculated, data processing in the main unit that directly controls the gas turbine can be facilitated.

[0073] (9) In another aspect, in the aspect (8), the control parameters corrected by the automatic correction unit can be transmitted to the external computing device.

[0074] According to the aspect (9) above, the control parameters corrected by the automatic correction unit are transmitted to an external computing device, whereby the corrected control parameters can be checked at a remote location away from the gas turbine. By making it possible to check the corrected control parameters externally in this way, a high degree of reliability in gas turbine control can be ensured.

[0075] (10) In another aspect, in any one of the aspects (1) to (9) above, the storage unit further comprises a driving data collection unit for collecting the driving data, and the storage unit updates the driving data stored in the storage unit using the driving data collected by the driving data collection unit so that the number of data included in a unit space in a multidimensional virtual space corresponding to a plurality of parameters included in the driving data is equal to or less than a predetermined value.

[0076] According to the above aspect (10), the driving data to be stored in the storage unit is collected so that the number of data included in a unit space in the multidimensional virtual space corresponding to each parameter included in the driving data is equal to or less than a predetermined value. This prevents the occurrence of an imbalance, such as an excessive number of data in a specific unit space, and enables the efficient collection of various driving data while suppressing the storage capacity of the storage unit.

[0077] (11) In another aspect, in any one of the aspects (1) to (10) above, the first fuel includes natural gas, and the second fuel includes hydrogen gas.

[0078] According to the above aspect (11), in a gas turbine equipped with a combustor capable of co-firing natural gas with hydrogen gas, which has a higher combustion rate than natural gas, even when the co-firing ratio of hydrogen gas changes, it is possible to preferably maintain a stable operating state while avoiding combustion fluctuations in accordance with the co-firing ratio. Note that blast furnace gas may be used as the first fuel.

[0079] (12) In another aspect, in any one of the above aspects (1) to (11), the second fuel has a higher combustion rate than the first fuel.

[0080] According to the above aspect (12), in a gas turbine using a fuel having a higher combustion rate than the first fuel as the second fuel, the stability of the operating state of the gas turbine can be suitably maintained.

[0081] (13) A gas turbine control method according to one aspect is a gas turbine control method for controlling a gas turbine including a combustor capable of mixing and burning a first fuel and a second fuel having a combustion speed different from that of the first fuel, the method comprising: controlling control parameters of the gas turbine so as to operate the gas turbine at a predetermined operating point; and automatically correcting the control parameters using a combustion oscillation model that is stored in a storage unit and constructed based on operating data that associates a combustion oscillation index that indicates combustion oscillation in the combustor with a mixing ratio of the second fuel, so that the operating point is included in a non-combustion oscillation region in which the combustion oscillation index that corresponds to the mixing ratio at the operating point is equal to or less than a first reference value.

[0082] According to the above aspect (13), the control parameters of the gas turbine are automatically corrected using a combustion oscillation model so that the operating point of the gas turbine is included in a non-combustion oscillation region where a combustion oscillation index corresponding to the combustion ratio is equal to or less than a first reference value. In particular, the construction of the combustion oscillation model used by the automatic correction unit and the calculation of the control parameters are performed based on the combustion ratio of the second fuel, so that the control parameters are automatically corrected in accordance with the combustion ratio of the second fuel. As a result, even if the operating point of the gas turbine changes due to a change in the combustion ratio of the second fuel, the operating point of the gas turbine is automatically controlled to be within the non-combustion oscillation region, so that combustion oscillation can be avoided in accordance with the combustion ratio of the second fuel and the stability of the operating state of the gas turbine can be favorably maintained.

[0083] (14) A gas turbine control program according to one aspect is a gas turbine control program for controlling a gas turbine including a combustor capable of mixing and burning a first fuel and a second fuel having a combustion speed different from that of the first fuel, the program being capable of causing a computer device to execute the following steps: controlling control parameters of the gas turbine so as to operate the gas turbine at a predetermined operating point; and automatically correcting the control parameters by using a combustion oscillation model that is stored in a storage unit and that is constructed based on operating data that associates a combustion oscillation index that indicates combustion oscillation in the combustor with a mixing ratio of the second fuel, so that the operating point is included in a non-combustion oscillation region in which the combustion oscillation index that corresponds to the mixing ratio at the operating point is equal to or less than a first reference value.

[0084] According to aspect (14) above, the control parameters of the gas turbine are automatically corrected using a combustion oscillation model so that the operating point of the gas turbine is included in a non-combustion oscillation region where a combustion oscillation index corresponding to the combustion mixture ratio is equal to or less than a first reference value. In particular, the construction of the combustion oscillation model used by the automatic correction unit and the calculation of the control parameters are performed based on the combustion mixture ratio of the second fuel, so that the control parameters are automatically corrected in accordance with the combustion mixture ratio of the second fuel. As a result, even if the operating point of the gas turbine changes due to a change in the combustion mixture ratio of the second fuel, the operating point of the gas turbine is automatically controlled to be within the non-combustion oscillation region, so that combustion oscillation can be avoided in accordance with the combustion mixture ratio of the second fuel and the stability of the operating state of the gas turbine can be favorably maintained.

[0085] REFERENCE SIGNS LIST 1 Gas turbine 2 Combustor 3 Compressor 4 Fuel supply system 6 Turbine 7 First fuel supply source 8 First fuel supply line 10 Flow meter 13 Shutoff valve 14 Second fuel supply source 15 Flow meter 16 Second fuel supply line 18 Flow control valve 25 Junction 22 Mixing line 24 Shutoff valve 26 Flow control valve 28a Main fuel supply line 28b Pilot fuel supply line 28c Top hat fuel supply line 100 Main control device 110 Operation data acquisition unit 120 Control parameter calculation unit 130 Control unit 200 External control device 210 Operation data collection unit 220 Memory unit 230 Combustion oscillation model construction unit 240 Combustion oscillation index calculation unit 250 Automatic correction unit 260 Operation restriction index calculation unit 270 Monitoring unit

Claims

1. A gas turbine control device for controlling a gas turbine equipped with a combustor capable of co-firing a first fuel and a second fuel having a combustion speed different from that of the first fuel, comprising: a control unit for controlling control parameters of the gas turbine so as to operate the gas turbine at a predetermined operating point; a memory unit for storing operating data correlating a combustion oscillation index indicating combustion oscillation in the combustor with a co-firing ratio of the second fuel; and an automatic correction unit for automatically correcting the control parameters by using a combustion oscillation model constructed based on the operating data stored in the memory unit, so that the operating point is included in a non-combustion oscillation region where the combustion oscillation index corresponding to the co-firing ratio at the operating point is equal to or less than a first reference value.

2. The gas turbine control device according to claim 1, further comprising a combustion oscillation model construction unit for constructing the combustion oscillation model by analyzing the operational data using at least the mixed-fuel ratio as an explanatory variable and the combustion oscillation index as an objective function.

3. The gas turbine control device according to claim 1 or 2, wherein the automatic correction unit corrects the control parameters so as to change the operating point to a region where an operational restriction index in the combustor, which is variably corrected for the mixed-fuel ratio, is equal to or less than a second reference value.

4. The gas turbine control device according to claim 3, wherein the operational limiting indicator is a limiting indicator indicating the possibility of a flashback or a misfire occurring.

5. The gas turbine control device according to claim 1 or 2, wherein the non-combustion oscillation region is identified so as to avoid operating points where the combustion oscillation has occurred in the past.

6. A gas turbine control device according to claim 1 or 2, wherein the automatic correction unit corrects the control parameter by modifying a function for calculating the control parameter based on the operating data.

7. A gas turbine control device according to claim 1 or 2, wherein the automatic correction unit determines a correction amount for the control parameter based on the load factor of the gas turbine and the mixed combustion ratio.

8. A gas turbine control device according to claim 1 or 2, wherein the automatic correction unit is configured as an external computing device capable of communicating with the control unit.

9. The gas turbine control device according to claim 8, wherein the control parameter corrected by the automatic correction unit can be transmitted to the external computing device.

10. A gas turbine control device as described in claim 1 or 2, further comprising an operating data collection unit for collecting the operating data in the memory unit, and the memory unit updates the operating data stored in the memory unit using the operating data collected by the operating data collection unit so that the number of data included in a unit space in a multidimensional virtual space corresponding to a plurality of parameters included in the operating data is equal to or less than a predetermined value.

11. The gas turbine control device according to claim 1 or 2, wherein the first fuel includes natural gas, and the second fuel includes hydrogen gas.

12. A gas turbine control device as claimed in claim 1 or 2, wherein the second fuel has a higher combustion velocity than the first fuel.

13. A gas turbine control method for controlling a gas turbine equipped with a combustor capable of co-firing a first fuel and a second fuel having a combustion speed different from that of the first fuel, comprising: a step of controlling control parameters of the gas turbine so as to operate the gas turbine at a predetermined operating point; and a step of automatically correcting the control parameters using a combustion oscillation model constructed based on operating data stored in a memory unit and relating a combustion oscillation index indicating combustion oscillation in the combustor to a co-firing ratio of the second fuel, so that the operating point is included in a non-combustion oscillation region where the combustion oscillation index corresponding to the co-firing ratio at the operating point is equal to or less than a first reference value.

14. A gas turbine control program for controlling a gas turbine equipped with a combustor capable of co-firing a first fuel and a second fuel having a combustion speed different from that of the first fuel, the gas turbine control program being capable of executing, on a computer device, the steps of: controlling control parameters of the gas turbine so as to operate the gas turbine at a predetermined operating point; and automatically correcting the control parameters using a combustion oscillation model stored in a memory unit and constructed based on operating data correlating a combustion oscillation index indicating combustion oscillation in the combustor with a co-firing ratio of the second fuel, so that the operating point is included in a non-combustion oscillation region where the combustion oscillation index corresponding to the co-firing ratio at the operating point is equal to or lower than a first reference value.