Gas turbine system

Abstract

To provide a gas turbine system that enables improvement of efficiency of the gas turbine system.SOLUTION: A gas turbine system 1 includes: an ammonia tank 13 that stores ammonia; a combustor 12 connected to the ammonia tank 13; an exhaust flow passage 102 connected to the combustor 12; a boiler 14 provided in the exhaust flow passage 102; a steam turbine 16 connected to the boiler 14; a condenser 17 connected to the steam turbine 16; a seawater flow passage 107 (heating medium flow passage) that passes through the condenser 17; and a heat exchanger 20 that is disposed on the upstream side of the condenser 17 in the seawater flow passage 107, on the downstream side of the condenser 17 in the seawater flow passage 107 or in a flow passage 106 connecting the steam turbine 16, the condenser 17 and the boiler 14 and through which an ammonia flow passage 103 connecting the ammonia tank 13 and the combustor 12 passes.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This application claims the benefit of priority from Japanese Patent Application No. 2022-041292, filed on March 16, 2022, the contents of which are incorporated herein by reference. [Background technology]

[0002] Gas turbine systems that obtain power by burning fuel in a combustor are used. For example, as disclosed in Patent Document 1, some gas turbine systems use ammonia as fuel. Using ammonia as fuel reduces carbon dioxide emissions. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-191507 Summary of the Invention [Problem to be solved by the invention]

[0004] One gas turbine system uses heat from exhaust gas discharged from a combustor to generate steam in a boiler, which then drives a steam turbine. The steam that passes through the steam turbine is liquefied in a condenser by heat exchange with a heat medium such as seawater. To avoid adverse effects on ecosystems, it is necessary to prevent the temperature of the heat medium, such as seawater, that is discharged after heat exchange with the steam from becoming excessively high. Therefore, a large amount of heat medium, such as seawater, must be taken in by a pump and supplied to the condenser. As the amount of heat medium, such as seawater, taken in, increases, the required power also increases, resulting in a decrease in the efficiency of the gas turbine system.

[0005] An object of the present disclosure is to provide a gas turbine system that can improve the efficiency of the gas turbine system. [Means for solving the problem]

[0006] In order to solve the above problems, a gas turbine system according to the present disclosure includes an ammonia tank for storing ammonia, a combustor connected to the ammonia tank, an exhaust flow path connected to the combustor, a boiler provided in the exhaust flow path, a steam turbine connected to the boiler, a condenser connected to the steam turbine, a heat medium flow path that passes through the condenser, and a heat exchanger that is disposed in the heat medium flow path upstream of the condenser, in the heat medium flow path downstream of the condenser, or in a flow path that connects the steam turbine, the condenser, and the boiler, and through which the ammonia flow path connecting the ammonia tank and the combustor passes.

[0007] Ammonia may be stored in the ammonia tank in a liquid state, and the ammonia may be supplied to the combustor in a liquid state.

[0008] The heat exchanger may include a first heat exchanger arranged upstream of the condenser in the heat medium flow path, and a second heat exchanger arranged downstream of the condenser in the heat medium flow path, and the ammonia flow path may be provided with a switching mechanism that switches the path of the ammonia between a plurality of states in which the heat exchangers through which the ammonia passes are different from each other.

[0009] The switching mechanism may switch the path of the ammonia based on at least one of the state of the ammonia in the ammonia flow path and the state of the heat medium in the heat medium flow path. [Effects of the Invention]

[0010] According to the present disclosure, the efficiency of a gas turbine system can be improved. [Brief explanation of the drawings]

[0011] [Figure 1]FIG. 1 is a schematic diagram showing the configuration of a gas turbine system according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is a schematic diagram showing the configuration of a gas turbine system according to a first modified example. [Figure 3] FIG. 3 is a schematic diagram showing the configuration of a gas turbine system according to a second modified example. [Figure 4] FIG. 4 is a schematic diagram showing the configuration of a gas turbine system according to a third modified example. [Figure 5] FIG. 5 is a schematic diagram showing the configuration of a gas turbine system according to a fourth modified example. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. Dimensions, materials, and other specific numerical values ​​shown in the embodiments are merely examples for ease of understanding and, unless otherwise specified, do not limit the present disclosure. In this specification and drawings, elements having substantially the same functions and configurations are designated by the same reference numerals to avoid redundant explanation, and elements not directly related to the present disclosure are not shown.

[0013] Fig. 1 is a schematic diagram showing the configuration of a gas turbine system 1 according to this embodiment. As shown in Fig. 1, the gas turbine system 1 includes a compressor 11a, a turbine 11b, a combustor 12, an ammonia tank 13, a boiler 14, an exhaust tower 15, a steam turbine 16, a condenser 17, a pump 18, a pump 19, a heat exchanger 20, a pump 21, and a flow control valve 22.

[0014] The compressor 11a and the turbine 11b rotate as a unit and are connected to each other by a shaft.

[0015] The compressor 11a is provided in an intake air flow path 101 connected to the combustor 12. Air to be supplied to the combustor 12 flows through the intake air flow path 101. An intake port (not shown) through which air is taken in from the outside is provided at the upstream end of the intake air flow path 101. The air taken in through the intake port passes through the compressor 11a and is sent to the combustor 12. The compressor 11a compresses the air and discharges it downstream.

[0016] The turbine 11b is provided in an exhaust flow path 102 connected to the combustor 12. Exhaust gas discharged from the combustor 12 flows through the exhaust flow path 102. The exhaust gas discharged from the combustor 12 passes through the turbine 11b and is sent to a portion of the exhaust flow path 102 downstream of the turbine 11b. The turbine 11b is rotated by the exhaust gas to generate rotational power.

[0017] The compressor 11a is connected to a generator (not shown), and the rotational power transmitted from the turbine 11b to the compressor 11a is used to generate electricity by the generator.

[0018] The combustor 12 is supplied with air compressed by the compressor 11a from the intake air flow path 101, and also with ammonia in a liquid state as fuel from an ammonia tank 13. However, as will be described later, ammonia may be supplied to the combustor 12 in a gaseous state. In the combustor 12, combustion is performed using ammonia as fuel. Exhaust gas generated in the combustor 12 is discharged to the exhaust flow path 102.

[0019] Ammonia is stored in a liquid state in the ammonia tank 13. In the ammonia tank 13, the ammonia is maintained in a liquid state at, for example, atmospheric pressure and −33° C. By storing ammonia in the ammonia tank 13 in this low-temperature liquid state, the vapor pressure inside the ammonia tank 13 is suppressed, and problems with the strength and structure of the tank are suppressed.

[0020] The ammonia tank 13 is connected to the combustor 12 via an ammonia flow path 103. Ammonia flows through the ammonia flow path 103. Ammonia is supplied from the ammonia tank 13 to the combustor 12 via the ammonia flow path 103. The ammonia flow path 103 will be described in detail later.

[0021] A boiler 14 is provided in the exhaust flow path 102 downstream of the turbine 11b. The boiler 14 is provided with a flow path 104 through which water flows. The water flowing through the flow path 104 is heated by the exhaust gas flowing through the exhaust flow path 102 and vaporizes into gas (i.e., steam). The steam generated in the boiler 14 is used for power generation, as will be described later. The exhaust flow path 102 is connected to an exhaust stack 15 downstream of the boiler 14. The exhaust gas discharged from the combustor 12 passes through the turbine 11b and the boiler 14, is sent to the exhaust stack 15, and is discharged from the exhaust stack 15.

[0022] The boiler 14 is connected to the steam turbine 16. Specifically, the outlet of the flow path 104 of the boiler 14 is connected to the inlet of the steam turbine 16 via a flow path 105. The steam generated in the boiler 14 is sent to the steam turbine 16 via the flow path 105. The steam then rotates the steam turbine 16, generating rotational power. The rotational power generated by the steam turbine 16 is used to generate power.

[0023] The steam turbine 16 is connected to the condenser 17. Specifically, an outlet of the steam turbine 16 is connected to an inlet of a flow path 104 of the boiler 14 via a flow path 106. The condenser 17 is disposed in such a flow path 106. A seawater flow path 107 passes through the condenser 17. Seawater flows through the seawater flow path 107. The seawater flow path 107 corresponds to an example of a heat medium flow path through which a heat medium flows. In other words, seawater corresponds to an example of a heat medium flowing through a heat medium flow path. In addition to seawater, examples of the heat medium include river water, groundwater, and air.

[0024] In the condenser 17, heat exchange occurs between the water vapor flowing through the flow path 106 and the seawater flowing through the seawater flow path 107. The temperature of the water vapor flowing through the flow path 106 is higher than the temperature of the seawater flowing through the seawater flow path 107. Therefore, in the condenser 17, the seawater flowing through the seawater flow path 107 cools the water vapor flowing through the flow path 106 and liquefies it into water. Details of the seawater flow path 107 will be described later.

[0025] A pump 18 is provided in the flow path 106 downstream of the condenser 17. The pump 18 pressurizes the water generated in the condenser 17 and sends it downstream. The water sent by the pump 18 is sent to the flow path 104 of the boiler 14.

[0026] Seawater taken in from the sea flows through the seawater flow path 107. Seawater that passes through the seawater flow path 107 is discharged back into the sea. A pump 19 is provided in the seawater flow path 107 upstream of the condenser 17. The pump 19 pressurizes the seawater and sends it downstream. This causes seawater to be taken in from the sea into the seawater flow path 107.

[0027] A heat exchanger 20 is disposed in the seawater passage 107 between the pump 19 and the condenser 17. An ammonia passage 103 passes through the heat exchanger 20. A pump 21 is provided in the ammonia passage 103 between the heat exchanger 20 and the ammonia tank 13. The pump 21 pressurizes ammonia supplied from the ammonia tank 13 and sends it downstream. The ammonia sent by the pump 21 is sent to the heat exchanger 20.

[0028] In the heat exchanger 20, heat is exchanged between the seawater flowing through the seawater passage 107 and the ammonia flowing through the ammonia passage 103. The temperature of the seawater flowing through the seawater passage 107 is higher than the temperature of the ammonia flowing through the ammonia passage 103. Therefore, in the heat exchanger 20, the seawater flowing through the seawater passage 107 is cooled by the ammonia flowing through the ammonia passage 103. On the other hand, the ammonia flowing through the ammonia passage 103 is heated by the seawater flowing through the seawater passage 107. In the heat exchanger 20, the ammonia is heated to a degree that does not cause it to vaporize. Therefore, the ammonia is supplied to the combustor 12 in a liquid state.

[0029] A flow control valve 22 is provided in the ammonia flow path 103 between the heat exchanger 20 and the combustor 12. The flow control valve 22 adjusts the flow rate of liquid ammonia sent to the combustor 12 through the ammonia flow path 103. Specifically, the amount of ammonia supplied to the combustor 12 is adjusted by adjusting the opening degree of the flow control valve 22.

[0030] As described above, in the gas turbine system 1, the heat exchanger 20, through which the ammonia flow path 103 connecting the ammonia tank 13 and the combustor 12 passes, is disposed in the seawater flow path 107 upstream of the condenser 17. This allows the heat exchanger 20 to cool the seawater flowing through the seawater flow path 107 using the ammonia flowing through the ammonia flow path 103. This makes it possible to increase the temperature difference between the seawater and the steam in the condenser 17. Therefore, even if the amount of seawater intake is reduced, the cooling effect of the seawater on the steam can be maintained. This allows the power of the pump 19 to be reduced, thereby improving the efficiency of the gas turbine system 1.

[0031] Furthermore, in the gas turbine system 1, the ammonia supplied to the combustor 12 can be heated in the heat exchanger 20 by using seawater flowing through the seawater flow path 107. Therefore, part of the energy required to combust the ammonia can be provided by the heat of the seawater. This also improves the efficiency of the gas turbine system 1.

[0032] In particular, in the gas turbine system 1, the heat exchanger 20 heats the ammonia to a degree that does not cause it to vaporize. That is, in the heat exchanger 20, the heat of the seawater is utilized as sensible heat of the ammonia. Therefore, the ammonia stored in a liquid state in the ammonia tank 13 is supplied to the combustor 12 in a liquid state without being vaporized in the ammonia flow path 103. If the ammonia were to vaporize in the ammonia flow path 103, additional equipment and complex control would be required to suppress pressure fluctuations of the vaporized ammonia and to prevent recondensation. This would also require enlarging the piping through which the gaseous ammonia flows. On the other hand, in the gas turbine system 1, these problems do not occur because the ammonia does not vaporize in the ammonia flow path 103.

[0033] Specifically, from the viewpoint of effectively improving the efficiency of the gas turbine system 1, it is preferable to provide a pump 21 for pressurizing ammonia in the ammonia flow path 103 between the heat exchanger 20 and the ammonia tank 13, as in the above example. As a result, the ammonia stored in the ammonia tank 13 is pressurized by the pump 21 and then sent to the heat exchanger 20. Therefore, the sensible heat required to vaporize the ammonia passing through the heat exchanger 20 increases. Therefore, the amount of heat that can be recovered from seawater within a range in which the ammonia passing through the heat exchanger 20 is not vaporized (i.e., the amount of heat that can be recovered as sensible heat) increases. Therefore, it is possible to increase the proportion of the energy required to combust ammonia that is supplied by the heat of seawater, and therefore it is possible to effectively improve the efficiency of the gas turbine system 1.

[0034] Furthermore, in the gas turbine system 1, the heat exchanger 20 can cool the seawater flowing through the seawater passage 107 by using the ammonia flowing through the ammonia passage 103. This increases the temperature difference between the seawater and the steam in the condenser 17. This allows a smaller amount of seawater to be taken in (i.e., the power consumption of the pump 19 can be reduced), and the water generated by the condenser 17 can be made at a lower temperature. The lower temperature of the condensed water reduces the outlet pressure of the steam turbine 16, and therefore increases the energy that can be extracted by the thermal cycle of the water passing through the boiler 14, steam turbine 16, and condenser 17. This also improves the efficiency of the gas turbine system 1.

[0035] Furthermore, in the gas turbine system 1, even when the steam turbine 16 is not started, the pump 19 can be operated to heat the flame-resistant ammonia stored in the ammonia tank 13 at a low temperature, thereby enabling early and stable combustion in the combustor 12, and ultimately allowing the gas turbine system 1 to be started up early.

[0036] In the above, an example has been described in which the heat exchanger 20 is disposed upstream of the condenser 17 in the seawater flow path 107. However, the heat exchanger 20 may be disposed downstream of the condenser 17 in the seawater flow path 107, as in the second heat exchanger 20b of the gas turbine system 1A of FIG. 2 or the gas turbine system 1B of FIG. 3, which will be described later. In this case, the heat exchanger 20 can cool the seawater flowing through the seawater flow path 107 using the ammonia flowing through the ammonia flow path 103, thereby achieving the same effects as those of the gas turbine system 1 described above. Furthermore, the heat exchanger 20 may be disposed in the flow path 106 connecting the steam turbine 16, the condenser 17, and the boiler 14, as in the gas turbine system 1C of FIG. 4 or the gas turbine system 1D of FIG. 5, which will be described later. In this case, the amount of seawater taken in can be reduced, as in the gas turbine system 1 described above, thereby improving the efficiency of the gas turbine system 1.

[0037] Hereinafter, gas turbine systems according to the respective modifications will be described with reference to FIGS.

[0038] Fig. 2 is a schematic diagram showing the configuration of a gas turbine system 1A according to a first modified example. As shown in Fig. 2, the gas turbine system 1A according to the first modified example differs from the gas turbine system 1 described above in that the number of heat exchangers 20 is two. The gas turbine system 1A is an embodiment that is particularly effective in regions where seawater temperatures are high, such as low latitude regions.

[0039] In the gas turbine system 1A, a first heat exchanger 20a and a second heat exchanger 20b are provided as the heat exchangers 20. The first heat exchanger 20a is disposed upstream of the condenser 17 in the seawater flow path 107. The second heat exchanger 20b is disposed downstream of the condenser 17 in the seawater flow path 107. The ammonia flow path 103 passes through both the first heat exchanger 20a and the second heat exchanger 20b.

[0040] A switching mechanism 30-1 that switches the ammonia path between a plurality of different states of the heat exchanger 20 through which the ammonia passes is provided in the ammonia flow path 103. The switching mechanism 30-1 includes branched portions of the ammonia flow path 103 (specifically, flow paths 103a and 103b, which will be described later), switching valves 31 and 32 that switch the ammonia path in the ammonia flow path 103, temperature sensors 33 and 34, and a control device 35.

[0041] 2, the ammonia flow path 103 branches into flow paths 103a and 103b downstream of the pump 21 after passing through the first heat exchanger 20a. The flow paths 103a and 103b merge with each other upstream of the flow control valve 22. The flow path 103b passes through the second heat exchanger 20b. On the other hand, the flow path 103a does not pass through the second heat exchanger 20b.

[0042] The switching valves 31 and 32 are on-off valves. Each switching valve opens and closes a flow path at an installation position. The switching valve 31 is provided in the flow path 103a. When the switching valve 31 is in an open state, the ammonia that has passed through the first heat exchanger 20a passes through the flow path 103a and is sent to the combustor 12. On the other hand, when the switching valve 31 is in a closed state, the ammonia that has passed through the first heat exchanger 20a cannot pass through the flow path 103a. The switching valve 32 is provided in the flow path 103b, upstream of the second heat exchanger 20b. When the switching valve 32 is in an open state, the ammonia that has passed through the first heat exchanger 20a passes through the second heat exchanger 20b and is sent to the combustor 12. On the other hand, when the switching valve 32 is in a closed state, the ammonia that has passed through the first heat exchanger 20a is not sent to the second heat exchanger 20b.

[0043] For example, by opening the switching valve 31 and closing the switching valve 32, the switching mechanism 30-1 can pass the ammonia only through the first heat exchanger 20a and send it to the combustor 12. Furthermore, by closing the switching valve 31 and opening the switching valve 32, the switching mechanism 30-1 can pass the ammonia through both the first heat exchanger 20a and the second heat exchanger 20b and send it to the combustor 12. In this way, the switching mechanism 30-1 switches the path of the ammonia between a state in which the ammonia passes only through the first heat exchanger 20a and a state in which the ammonia passes through both the first heat exchanger 20a and the second heat exchanger 20b.

[0044] In the above, an example has been described in which the switching valves 31 and 32 are on-off valves. However, the switching valves provided in the switching mechanism 30-1 do not have to be on-off valves. For example, a three-way switching valve may be provided at the connection between the upstream end of the flow path 103a and the upstream end of the flow path 103b. By switching the ammonia path in the ammonia flow path 103 between a state in which the ammonia passes through the flow path 103a and a state in which the ammonia passes through the flow path 103b, the heat exchanger 20 through which the ammonia passes can be switched, as in the above example. Furthermore, in the switching mechanism 30-1, the number and connection positions of the branching portions of the ammonia flow path 103 are not particularly limited. That is, in the switching mechanism 30-1, the branching manner of the ammonia flow path 103 is not particularly limited. The switching valves 31 and 32 may be flow control valves having a function of adjusting the flow rate. In this case, the flow rate of the ammonia sent to each of the first heat exchanger 20a and the second heat exchanger 20b can be more precisely adjusted.

[0045] The temperature sensor 33 detects the temperature of the ammonia that has passed through the first heat exchanger 20a and outputs the detection result to the control device 35. The temperature sensor 33 is provided, for example, in the ammonia flow path 103, between the first heat exchanger 20a and a connection portion between the upstream end of the flow path 103a and the upstream end of the flow path 103b.

[0046] The temperature sensor 34 detects the temperature of the seawater discharged into the sea, and outputs the detection result to the control device 35. The temperature sensor 34 is provided, for example, in the seawater flow path 107, downstream of the second heat exchanger 20b.

[0047] The control device 35 includes a central processing unit (CPU), a ROM in which programs and the like are stored, a RAM as a work area, and the like. In the gas turbine system 1A, the control device 35 controls the operations of the switching valves 31 and 32. This allows the control device 35 to switch the path of the ammonia between a state in which the ammonia passes only through the first heat exchanger 20a and a state in which the ammonia passes through both the first heat exchanger 20a and the second heat exchanger 20b.

[0048] The control device 35 may switch the path of the ammonia based on, for example, the state of the ammonia in the ammonia flow path 103. In the example of Fig. 2, the control device 35 switches the path of the ammonia based on, for example, the temperature of the ammonia that has passed through the first heat exchanger 20a.

[0049] For example, when the temperature of the ammonia that has passed through first heat exchanger 20a is equal to or lower than the target temperature, control device 35 controls switching valves 31 and 32 so that the ammonia passes through flow path 103b, causing the ammonia to pass through both first heat exchanger 20a and second heat exchanger 20b. On the other hand, when the temperature of the ammonia that has passed through first heat exchanger 20a is higher than the target temperature, control device 35 controls switching valves 31 and 32 so that the ammonia passes through flow path 103a, causing the ammonia to pass only through first heat exchanger 20a.

[0050] The target temperature is a target to be reached by heating the ammonia with seawater. For example, the target temperature is set to a temperature as high as possible within a range in which the ammonia does not vaporize.

[0051] By switching the ammonia path as described above, the amount of heat recovered from seawater by the ammonia passing through the heat exchanger 20 can be maximized while suppressing the evaporation of the ammonia.

[0052] In the above, an example has been described in which the switching mechanism 30-1 switches the ammonia path based on the temperature of the ammonia that has passed through the first heat exchanger 20a. However, the switching mechanism 30-1 may switch the ammonia path based on a parameter other than the above temperature as a parameter indicating the state of ammonia in the ammonia flow path 103. For example, the flow rate of ammonia in the ammonia flow path 103 may be used as the parameter indicating the state of ammonia in the ammonia flow path 103. For example, the pressure of ammonia in the ammonia flow path 103 may be used as the parameter indicating the state of ammonia in the ammonia flow path 103.

[0053] Furthermore, the control device 35 may switch the ammonia path based on, for example, the state of seawater in the seawater flow path 107. In the example of Fig. 2, the control device 35 switches the ammonia path based on, for example, the temperature of the seawater discharged into the sea.

[0054] For example, when the temperature of seawater discharged into the sea is equal to or lower than a reference temperature, the control device 35 controls the switching valves 31 and 32 so that ammonia passes through the flow path 103a, and passes the ammonia only through the first heat exchanger 20a. On the other hand, when the temperature of seawater discharged into the sea is higher than the reference temperature, the control device 35 controls the switching valves 31 and 32 so that ammonia passes through the flow path 103b, and passes the ammonia through both the first heat exchanger 20a and the second heat exchanger 20b.

[0055] The reference temperature is an index used to determine whether the temperature of seawater discharged into the ocean is excessively high (for example, whether the seawater is high enough to have a negative impact on the ecosystem). If the temperature of seawater discharged into the ocean is below the reference temperature, it can be determined that the temperature of the seawater discharged into the ocean is not excessively high. On the other hand, if the temperature of seawater discharged into the ocean is higher than the reference temperature, it can be determined that the temperature of the seawater discharged into the ocean is excessively high.

[0056] By switching the ammonia path as described above, it is possible to prevent the temperature of the seawater discharged into the sea from becoming excessively high, while also preventing the seawater from being excessively cooled and solidified in the seawater flow path 107.

[0057] In the above, an example has been described in which the switching mechanism 30-1 switches the ammonia path based on the temperature of seawater discharged into the sea. However, the switching mechanism 30-1 may switch the ammonia path based on a parameter other than the temperature as a parameter indicating the state of seawater in the seawater flow path 107. For example, the flow rate of seawater in the seawater flow path 107 may be used as the parameter indicating the state of seawater in the seawater flow path 107. For example, the pressure of seawater in the seawater flow path 107 may be used as the parameter indicating the state of seawater in the seawater flow path 107.

[0058] As described above, in the gas turbine system 1A, the heat exchanger 20 includes the first heat exchanger 20a disposed in the seawater flow path 107 upstream of the condenser 17 and the second heat exchanger 20b disposed in the seawater flow path 107 downstream of the condenser 17. The ammonia flow path 103 is provided with a switching mechanism 30-1 that switches the ammonia path between a plurality of states in which the heat exchangers 20 through which the ammonia passes are different from one another. This makes it possible to change the number or types of heat exchangers 20 through which the ammonia passes in the ammonia flow path 103. In the example of FIG. 2, the number of heat exchangers 20 through which the ammonia passes can be changed. Therefore, in addition to the effects of the gas turbine system 1 described above, it is possible to adjust the degree of increase in the temperature of ammonia and the degree of decrease in the temperature of seawater due to heat exchange between seawater and ammonia. This makes it possible to improve the efficiency of the gas turbine system 1A while appropriately adjusting the temperature of the seawater.

[0059] In particular, as described above, it is preferable that the switching mechanism 30-1 switches the path of ammonia based on the state of ammonia in the ammonia flow path 103. This makes it possible to appropriately adjust the degree of temperature increase of ammonia due to heat exchange with seawater based on the state of ammonia in the ammonia flow path 103. Therefore, for example, it is possible to appropriately maximize the amount of heat recovered from seawater by ammonia passing through the heat exchanger 20 while suppressing vaporization of ammonia.

[0060] In particular, as described above, it is preferable that the switching mechanism 30-1 switches the ammonia path based on the state of seawater in the seawater flow path 107. This makes it possible to appropriately adjust the degree of decrease in temperature of the seawater due to heat exchange with ammonia based on the state of the seawater in the seawater flow path 107. Therefore, for example, it is possible to appropriately prevent the temperature of the seawater discharged into the sea from becoming excessively high, while also preventing the seawater in the seawater flow path 107 from being excessively cooled and solidifying.

[0061] The switching mechanism 30-1 may switch the path of the ammonia based on one of the state of ammonia in the ammonia flow path 103 and the state of seawater in the seawater flow path 107. The switching mechanism 30-1 may switch the path of the ammonia based on both the state of ammonia in the ammonia flow path 103 and the state of seawater in the seawater flow path 107. In other words, the switching mechanism 30-1 may switch the path of the ammonia based on at least one of the state of ammonia in the ammonia flow path 103 and the state of seawater in the seawater flow path 107.

[0062] Fig. 3 is a schematic diagram showing the configuration of a gas turbine system 1B according to a second modified example. As shown in Fig. 3, the gas turbine system 1B according to the second modified example is provided with a first heat exchanger 20a and a second heat exchanger 20b as the heat exchanger 20, similar to the gas turbine system 1A described above. However, compared to the gas turbine system 1A described above, the gas turbine system 1B according to the second modified example is provided with a switching mechanism 30-2 that is different from the switching mechanism 30-1. The gas turbine system 1B is an embodiment that is particularly effective in regions where seawater temperatures are low, such as high latitude regions.

[0063] Similar to the switching mechanism 30-1 described above, the switching mechanism 30-2 switches the path of ammonia between a plurality of states in which the heat exchanger 20 through which the ammonia passes is different. The switching mechanism 30-2 differs from the switching mechanism 30-1 described above in the branching location of the ammonia flow path 103. The switching mechanism 30-2 also includes switching valves 36 and 37 instead of the switching valves 31 and 32 of the switching mechanism 30-1 described above. The switching mechanism 30-2 also includes a temperature sensor 38 instead of the temperature sensor 33 of the switching mechanism 30-1 described above. Similar to the switching mechanism 30-1 described above, the switching mechanism 30-2 also includes a temperature sensor 34 and a control device 35.

[0064] 3, the ammonia flow path 103 branches into a flow path 103c and a flow path 103d downstream of the pump 21. The flow paths 103c and 103d merge with each other upstream of the flow control valve 22. The flow path 103c passes through the first heat exchanger 20a. On the other hand, the flow path 103d passes through the second heat exchanger 20b.

[0065] The switching valves 36 and 37 are on-off valves. Each of these switching valves opens and closes the flow path at an installation position. The switching valve 36 is provided in the flow path 103c upstream of the first heat exchanger 20a. When the switching valve 36 is open, the ammonia supplied from the ammonia tank 13 passes through the first heat exchanger 20a and is sent to the combustor 12. On the other hand, when the switching valve 36 is closed, the ammonia supplied from the ammonia tank 13 is not sent to the first heat exchanger 20a. The switching valve 37 is provided in the flow path 103d upstream of the second heat exchanger 20b. When the switching valve 37 is open, the ammonia supplied from the ammonia tank 13 passes through the second heat exchanger 20b and is sent to the combustor 12. On the other hand, when the switching valve 37 is closed, the ammonia supplied from the ammonia tank 13 is not sent to the second heat exchanger 20b.

[0066] For example, by closing the switching valve 36 and opening the switching valve 37, the switching mechanism 30-2 can pass the ammonia only through the second heat exchanger 20b and send it to the combustor 12. Furthermore, by opening both the switching valve 36 and the switching valve 37, the switching mechanism 30-2 can pass the ammonia through both the first heat exchanger 20a and the second heat exchanger 20b and send it to the combustor 12. In this way, the switching mechanism 30-2 switches the path of the ammonia between a state in which the ammonia passes only through the second heat exchanger 20b and a state in which the ammonia passes through both the first heat exchanger 20a and the second heat exchanger 20b.

[0067] In the above, an example has been described in which the switching valves 36 and 37 are on-off valves. However, like the above-described switching valves 31 and 32, the switching valves 36 and 37 do not have to be on-off valves. For example, some or all of the switching valves 36 and 37 may be replaced with switching valves that are three-way valves. Furthermore, in the switching mechanism 30-2, like the above-described switching mechanism 30-1, the number and connection positions of the branching portions of the ammonia flow path 103 are not particularly limited. In other words, in the switching mechanism 30-2, the manner in which the ammonia flow path 103 branches is not particularly limited. The switching valves 36 and 37 may be flow control valves that have the function of adjusting the flow rate. In this case, the flow rate of ammonia sent to each of the first heat exchanger 20a and the second heat exchanger 20b can be more precisely adjusted.

[0068] The temperature sensor 38 detects the temperature of the ammonia that has passed through the second heat exchanger 20b, and outputs the detection result to the control device 35. The temperature sensor 38 is provided, for example, in the flow path 103d, downstream of the second heat exchanger 20b.

[0069] In the gas turbine system 1B, the control device 35 controls the operations of the switching valves 36 and 37. This allows the control device 35 to switch the path of the ammonia between a state in which the ammonia passes only through the second heat exchanger 20b and a state in which the ammonia passes through both the first heat exchanger 20a and the second heat exchanger 20b.

[0070] 2, the control device 35 may switch the ammonia path based on the state of ammonia in the ammonia flow path 103. In the example of Fig. 3, the control device 35 switches the ammonia path based on, for example, the temperature of the ammonia that has passed through the second heat exchanger 20b.

[0071] For example, when the temperature of the ammonia that has passed through second heat exchanger 20b is higher than the target temperature, control device 35 controls switching valves 36 and 37 so that the ammonia passes only through flow path 103d out of flow paths 103c and 103d, and passes only through second heat exchanger 20b. On the other hand, when the temperature of the ammonia that has passed through second heat exchanger 20b is equal to or lower than the target temperature, control device 35 controls switching valves 36 and 37 so that the ammonia passes through both flow paths 103c and 103d, and passes the ammonia through both first heat exchanger 20a and second heat exchanger 20b.

[0072] By switching the ammonia path as described above, the amount of heat recovered from seawater by the ammonia passing through the heat exchanger 20 can be maximized while suppressing the evaporation of the ammonia.

[0073] The switching mechanism 30-2 may switch the path of the ammonia based on a parameter indicating the state of the ammonia in the ammonia flow path 103 other than the temperature, similar to the switching mechanism 30-1 described above.

[0074] 2, the control device 35 may switch the ammonia path based on the state of seawater in the seawater flow path 107. In the example of Fig. 3, the control device 35 switches the ammonia path based on, for example, the temperature of the seawater discharged into the sea.

[0075] For example, when the temperature of seawater discharged into the sea is equal to or lower than a reference temperature, the control device 35 controls the switching valves 36 and 37 so that ammonia passes only through the flow path 103d out of the flow paths 103c and 103d, and passes only through the second heat exchanger 20b. On the other hand, when the temperature of seawater discharged into the sea is higher than the reference temperature, the control device 35 controls the switching valves 36 and 37 so that ammonia passes through both the flow paths 103c and 103d, and passes the ammonia through both the first heat exchanger 20a and the second heat exchanger 20b.

[0076] By switching the ammonia path as described above, it is possible to prevent the temperature of the seawater discharged into the sea from becoming excessively high, while also preventing the seawater from being excessively cooled and solidified in the seawater flow path 107.

[0077] The switching mechanism 30-2 may switch the ammonia path based on a parameter indicating the state of seawater in the seawater flow path 107 other than the temperature, similar to the switching mechanism 30-1 described above.

[0078] In the above example, the switching mechanism 30-2 switches the ammonia path between a state in which ammonia passes only through the second heat exchanger 20b and a state in which ammonia passes through both the first heat exchanger 20a and the second heat exchanger 20b. However, the switching mechanism 30-2 may switch the ammonia path between a state in which ammonia passes only through the first heat exchanger 20a. For example, the degree of temperature increase of ammonia may differ between the first heat exchanger 20a and the second heat exchanger 20b. In this case, the switching mechanism 30-2 switches the ammonia path between a state in which ammonia passes only through the first heat exchanger 20a and a state in which ammonia passes only through the second heat exchanger 20b, for example, based on the flow rate of ammonia in the ammonia flow path 103. This makes it possible to maximize the amount of heat recovered from seawater by ammonia passing through the heat exchanger 20 while suppressing vaporization of ammonia.

[0079] As described above, in the gas turbine system 1B, similarly to the above-described gas turbine system 1A, the heat exchanger 20 includes the first heat exchanger 20a arranged in the seawater flow path 107 upstream of the condenser 17, and the second heat exchanger 20b arranged in the seawater flow path 107 downstream of the condenser 17. The ammonia flow path 103 is provided with a switching mechanism 30-2 that switches the ammonia path between a plurality of states in which the heat exchanger 20 through which the ammonia passes is different from one another. Therefore, the same effects as those of the above-described gas turbine system 1A are achieved.

[0080] 2 and 3, an example in which two heat exchangers 20 are provided in the seawater passage 107 has been described. However, three or more heat exchangers 20 may be provided in the seawater passage 107.

[0081] Fig. 4 is a schematic diagram showing the configuration of a gas turbine system 1C according to a third modification. As shown in Fig. 4, the gas turbine system 1C according to the third modification differs from the gas turbine system 1 described above in that a heat exchanger 20 is disposed in a flow path 106 connecting the steam turbine 16, the condenser 17, and the boiler 14.

[0082] In the example of FIG. 4 , a heat exchanger 20 is disposed in the flow path 106 between the steam turbine 16 and the condenser 17. The ammonia flow path 103 passes through the heat exchanger 20. In the heat exchanger 20, heat is exchanged between the water vapor discharged from the steam turbine 16 and flowing through the flow path 106 and the ammonia flowing through the ammonia flow path 103. The temperature of the water vapor flowing through the flow path 106 is higher than the temperature of the ammonia flowing through the ammonia flow path 103. Therefore, in the heat exchanger 20, the water vapor flowing through the flow path 106 is cooled by the ammonia flowing through the ammonia flow path 103. On the other hand, the ammonia flowing through the ammonia flow path 103 is heated by the water vapor flowing through the flow path 106.

[0083] As described above, in the gas turbine system 1C, the heat exchanger 20, through which the ammonia flow path 103 connecting the ammonia tank 13 and the combustor 12 passes, is disposed upstream of the condenser 17 in the flow path 106 connecting the steam turbine 16, the condenser 17, and the boiler 14. This allows the heat exchanger 20 to cool the steam sent to the condenser 17 using the ammonia flowing through the ammonia flow path 103. This reduces the amount of heat that needs to be recovered from the steam by seawater in the condenser 17, and therefore reduces the amount of seawater taken in. This reduces the power required for the pump 19, thereby improving the efficiency of the gas turbine system 1C.

[0084] Furthermore, the gas turbine system 1C can heat ammonia using steam, which has a higher temperature than seawater. Therefore, ammonia can be heated more effectively than when seawater is used to heat ammonia. This also improves the efficiency of the gas turbine system 1.

[0085] Fig. 5 is a schematic diagram showing the configuration of a gas turbine system 1D according to a fourth modified example. As shown in Fig. 5, in the gas turbine system 1D according to the fourth modified example, similar to the gas turbine system 1C described above, the heat exchanger 20 is arranged in the flow path 106 connecting the steam turbine 16, the condenser 17, and the boiler 14. However, unlike the gas turbine system 1C described above, in the gas turbine system 1D according to the fourth modified example, the heat exchanger 20 is arranged downstream of the condenser 17 in the flow path 106 connecting the steam turbine 16, the condenser 17, and the boiler 14.

[0086] In the example of FIG. 5 , a heat exchanger 20 is disposed in the flow path 106 between the condenser 17 and the pump 18. The ammonia flow path 103 passes through the heat exchanger 20. In the heat exchanger 20, heat is exchanged between the water generated in the condenser 17 and flowing through the flow path 106 and the ammonia flowing through the ammonia flow path 103. The temperature of the water flowing through the flow path 106 is higher than the temperature of the ammonia flowing through the ammonia flow path 103. Therefore, in the heat exchanger 20, the water flowing through the flow path 106 is cooled by the ammonia flowing through the ammonia flow path 103. Meanwhile, the ammonia flowing through the ammonia flow path 103 is heated by the water flowing through the flow path 106.

[0087] As described above, in the gas turbine system 1D, the heat exchanger 20, through which the ammonia flow path 103 connecting the ammonia tank 13 and the combustor 12 passes, is disposed downstream of the condenser 17 in the flow path 106 connecting the steam turbine 16, the condenser 17, and the boiler 14. This allows the water sent downstream from the condenser 17 to be cooled in the heat exchanger 20 by using the ammonia flowing through the ammonia flow path 103. Therefore, similar to the gas turbine system 1C described above, the amount of heat that needs to be recovered from the steam by seawater in the condenser 17 can be reduced, and the amount of seawater taken in can be reduced. This allows the power of the pump 19 to be reduced, thereby improving the efficiency of the gas turbine system 1D.

[0088] The temperature of the water sent downstream from the condenser 17 is lower than the temperature of the steam sent to the condenser 17. Therefore, in the gas turbine system 1D, the degree of increase in the temperature of ammonia is lower than in the gas turbine system 1C described above. Therefore, it is possible to suppress the vaporization of ammonia. This makes it possible to suppress the need for additional equipment and complex control to suppress pressure fluctuations of vaporized ammonia and prevent recondensation, as well as to suppress the need for larger piping for circulating gaseous ammonia.

[0089] Although the embodiments of the present disclosure have been described above with reference to the accompanying drawings, it goes without saying that the present disclosure is not limited to such embodiments. It is clear that a person skilled in the art can conceive of various modifications and alterations within the scope of the claims, and it is understood that such modifications and alterations also fall within the technical scope of the present disclosure.

[0090] In the above, an example has been described in which the rotational power transmitted from the turbine 11b to the compressor 11a is used as energy to drive the generator in the gas turbine systems 1, 1A, 1B, 1C, and 1D. However, in the gas turbine systems 1, 1A, 1B, 1C, and 1D, the rotational power transmitted from the turbine 11b to the compressor 11a may be used for other purposes, such as to drive a moving body such as a ship.

[0091] In the above, an example has been described in which ammonia is supplied in a liquid state to the combustor 12. However, ammonia may be supplied in a gaseous state to the combustor 12. In this case, a vaporizer is provided in the ammonia flow path 103, and the ammonia is vaporized by the vaporizer.

[0092] The condenser 17 and each heat exchanger 20 have been described above with reference to the drawings. However, the relationship between the flow direction of the high-temperature fluid and the flow direction of the low-temperature fluid in the condenser 17 and each heat exchanger 20 is not limited to the example shown in the drawings. For example, the condenser 17 and each heat exchanger 20 may be of a counterflow type, a parallel flow type, or a cross-flow type.

[0093] The present disclosure contributes to improving the efficiency of gas turbine systems, thereby contributing, for example, to Goal 7 of the Sustainable Development Goals (SDGs), "Ensure access to affordable, reliable, sustainable and modern energy." [Explanation of symbols]

[0094] 1: Gas turbine system 1A: Gas turbine system 1B: Gas turbine system 1C: Gas turbine system 1D: Gas turbine system 12: Combustor 13: Ammonia tank 14: Boiler 16: Steam turbine 17: Condenser 20: Heat exchanger 20a: First heat exchanger 20b: Second heat exchanger 30-1: Switching mechanism 30-2: Switching mechanism 102: Exhaust flow path 103: Ammonia flow path 106: Flow path 107: Seawater flow path (heat medium flow path)

Claims

1. an ammonia tank in which ammonia is stored; a combustor connected to the ammonia tank; an exhaust flow path connected to the combustor; a boiler provided in the exhaust flow path; a steam turbine connected to the boiler; a condenser connected to the steam turbine; a heat medium flow path passing through the condenser; a heat exchanger, which is disposed in the heat medium flow path upstream of the condenser, in the heat medium flow path downstream of the condenser, or in a flow path connecting the steam turbine, the condenser, and the boiler, and through which an ammonia flow path connecting the ammonia tank and the combustor passes; Equipped with Gas turbine systems.

2. The ammonia tank stores the ammonia in a liquid state, The ammonia is supplied to the combustor in a liquid state. The gas turbine system of claim 1 .

3. the heat exchanger includes a first heat exchanger arranged upstream of the condenser in the heat medium flow path, and a second heat exchanger arranged downstream of the condenser in the heat medium flow path, The ammonia flow path is provided with a switching mechanism that switches the path of the ammonia between a plurality of states in which the heat exchanger through which the ammonia passes is different from one another. The gas turbine system according to claim 1 or 2.

4. the switching mechanism switches the path of the ammonia based on at least one of a state of the ammonia in the ammonia flow path and a state of the heat medium in the heat medium flow path. The gas turbine system of claim 3 .

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