JP7729461B2 - Gas Turbine System - Google Patents

Description

This application claims the benefit of priority from Japanese Patent Application No. 2022-034697, filed on March 7, 2022, the contents of which are incorporated herein by reference.

2. Description of the Related Art Gas turbine systems are used that obtain power by burning fuel in a combustor. For example, as disclosed in Patent Document 1, there is a gas turbine system that uses ammonia as fuel. The use of ammonia as fuel reduces carbon dioxide emissions.

Japanese Patent Application Laid-Open No. 2016-191507

Large-scale gas turbine systems consume large amounts of fuel. For this reason, when ammonia is used as fuel, it is necessary to store large quantities of ammonia. When ammonia is made into a low-temperature liquid at around -33°C, its vapor pressure is almost atmospheric pressure. Therefore, when ammonia is stored in a tank, the internal pressure on the tank is reduced, making it less likely to cause problems with the tank's strength and structure. On the other hand, when low-temperature ammonia liquid is supplied directly to the combustor as gas turbine fuel, the heat required to raise the temperature of the ammonia liquid and vaporize it is provided by the heat of combustion of the ammonia, which poses the problem of reduced efficiency of the gas turbine system.

An object of the present disclosure is to provide a gas turbine system that can improve the efficiency of the gas turbine system.

In order to solve the above problems, a gas turbine system of the present disclosure includes an ammonia tank in which ammonia is stored in a liquid state, a combustor connected to the ammonia tank and to which ammonia is supplied in a liquid state, an exhaust flow path connected to the combustor, a boiler provided in the exhaust flow path, and a heat exchanger that is arranged in the exhaust flow path downstream of the boiler and through which the ammonia flow path connecting the ammonia tank and the combustor passes , and in the heat exchanger, the ammonia is heated to a degree that does not vaporize .

In the heat exchanger, a heat medium flow path may be interposed between the exhaust flow path and the ammonia flow path.

The heat exchanger includes a first heat exchanger and a second heat exchanger arranged in the exhaust flow path downstream of the first heat exchanger, and the ammonia flow path may be provided with a switching mechanism that switches the path of the ammonia so as to switch which heat exchanger the ammonia passes through .

The switching mechanism may switch the path of the ammonia based on at least one of the temperature, flow rate, and pressure of the ammonia in the ammonia flow path.

According to the present disclosure, the efficiency of a gas turbine system can be improved.

FIG. 1 is a schematic diagram illustrating the configuration of a gas turbine system according to an embodiment of the present disclosure. FIG. 2 is a schematic diagram showing the configuration of a gas turbine system according to a first modified example. FIG. 3 is a schematic diagram showing the configuration of a gas turbine system according to a second modified example. FIG. 4 is a schematic diagram showing the configuration of a gas turbine system according to a third modified example.

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.

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 heat exchanger 16, a pump 17, and a flow control valve 18.

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

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.

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.

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.

The combustor 12 receives air compressed by the compressor 11a through an intake passage 101, and also receives ammonia in a liquid state as fuel from an ammonia tank 13. Combustion is performed in the combustor 12 using the ammonia as fuel. Exhaust gas generated in the combustor 12 is discharged to an exhaust passage 102.

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, for example, at 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.

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.

A boiler 14 is provided downstream of the turbine 11b in the exhaust flow path 102. 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 a gas (i.e., steam). The flow path 104 of the boiler 14 is connected to a steam turbine (not shown). The steam generated in the boiler 14 is sent to the steam turbine. The steam then rotates the steam turbine, generating rotational power. The rotational power generated by the steam turbine is used to generate electricity.

The exhaust flow path 102 is connected to the 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.

A heat exchanger 16 is disposed in the exhaust gas flow path 102 downstream of the boiler 14. The ammonia flow path 103 passes through the heat exchanger 16. A pump 17 is provided in the ammonia flow path 103 between the heat exchanger 16 and the ammonia tank 13. The pump 17 pressurizes the ammonia supplied from the ammonia tank 13 and sends it downstream. The ammonia sent by the pump 17 is sent to the heat exchanger 16.

In the heat exchanger 16, heat is exchanged between the exhaust gas flowing through the exhaust passage 102 and the ammonia flowing through the ammonia passage 103. The temperature of the exhaust gas flowing through the exhaust passage 102 is higher than the temperature of the ammonia flowing through the ammonia passage 103. Therefore, in the heat exchanger 16, the ammonia flowing through the ammonia passage 103 is heated by the exhaust gas flowing through the exhaust passage 102. Specifically, in the heat exchanger 16, 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.

A flow control valve 18 is provided in the ammonia flow path 103 between the heat exchanger 16 and the combustor 12. The flow control valve 18 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 18.

As described above, in the gas turbine system 1, the heat exchanger 16, through which the ammonia flow path 103 connecting the ammonia tank 13 and the combustor 12 passes, is disposed downstream of the boiler 14 in the exhaust flow path 102. As a result, in the heat exchanger 16, the ammonia supplied to the combustor 12 can be heated using the heat of the exhaust gas that has passed through the boiler 14. Therefore, part of the energy required to combust the ammonia can be provided by the heat of the exhaust gas. As a result, the efficiency of the gas turbine system 1 can be improved.

Furthermore, in the gas turbine system 1, the ammonia is heated in the heat exchanger 16 to a degree that does not cause it to vaporize. That is, in the heat exchanger 16, the heat of the exhaust gas 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 vaporized 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, the ammonia is not vaporized in the ammonia flow path 103, so these problems do not occur.

Specifically, from the viewpoint of effectively improving the efficiency of the gas turbine system 1, it is preferable to provide a pump 17 for pressurizing ammonia in the ammonia flow path 103 between the heat exchanger 16 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 17 and then sent to the heat exchanger 16. Therefore, the boiling point of the ammonia passing through the heat exchanger 16 increases. This increases the amount of heat that can be recovered from the exhaust gas within a range in which the ammonia passing through the heat exchanger 16 does not vaporize (i.e., the amount of heat that can be recovered as sensible heat). Therefore, it is possible to increase the proportion of the energy required to combust ammonia that is provided by the heat of the exhaust gas, and therefore it is possible to effectively improve the efficiency of the gas turbine system 1.

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

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 a heat medium flow path 105 is interposed between the exhaust flow path 102 and the ammonia flow path 103 in the heat exchanger 16.

A heat medium such as water flows through the heat medium flow path 105. The supply source of the heat medium flowing through the heat medium flow path 105 is not particularly limited. For example, the heat medium flow path 105 may be in communication with the flow path 104 of the boiler 14, and the heat medium flowing through the heat medium flow path 105 may be water circulating through the flow path 104. Alternatively, the heat medium flow path 105 may not be in communication with the flow path 104 of the boiler 14, and the heat medium flowing through the heat medium flow path 105 may be a heat medium such as water supplied from a supply source other than the flow path 104.

In the gas turbine system 1A, in the heat exchanger 16, the exhaust passage 102 and the ammonia passage 103 face each other with the heat medium passage 105 interposed therebetween. Therefore, in the heat exchanger 16, heat exchange is performed indirectly between the exhaust gas flowing through the exhaust passage 102 and the ammonia flowing through the ammonia passage 103 via the heat medium flowing through the heat medium passage 105. Specifically, heat exchange is performed directly between the exhaust gas flowing through the exhaust passage 102 and the heat medium flowing through the heat medium passage 105. Furthermore, heat exchange is performed directly between the heat medium flowing through the heat medium passage 105 and the ammonia flowing through the ammonia passage 103.

As described above, in the gas turbine system 1A, the heat exchanger 16 has the heat medium flow path 105 interposed between the exhaust flow path 102 and the ammonia flow path 103. Therefore, by adjusting the flow rate of the heat medium flowing through the heat medium flow path 105, it is possible to adjust the amount of heat exchanged between the exhaust gas flowing through the exhaust flow path 102 and the ammonia flowing through the ammonia flow path 103. This makes it possible to maximize the amount of heat recovered from the exhaust gas by the ammonia passing through the heat exchanger 16 while suppressing vaporization of the ammonia.

Fig. 3 is a schematic diagram showing the configuration of a gas turbine system 1B according to a second modification. As shown in Fig. 3, the gas turbine system 1B according to the second modification is different from the gas turbine system 1 described above in that the number of heat exchangers 16 is two.

In the gas turbine system 1B, a first heat exchanger 16a and a second heat exchanger 16b are provided as the heat exchangers 16. The first heat exchanger 16a and the second heat exchanger 16b are arranged in this order from the upstream side in the exhaust flow path 102. In other words, the second heat exchanger 16b is arranged downstream of the first heat exchanger 16a in the exhaust flow path 102. The ammonia flow path 103 passes through both the first heat exchanger 16a and the second heat exchanger 16b.

A switching mechanism 20-1 that switches the ammonia path between a plurality of different states of the heat exchanger 16 through which the ammonia passes is provided in the ammonia flow path 103. The switching mechanism 20-1 includes a branched portion of the ammonia flow path 103 (specifically, flow paths 103a and 103b, which will be described later), a switching valve 21 that switches the ammonia path in the ammonia flow path 103, a temperature sensor 22, and a control device 23.

3, the ammonia flow path 103 branches into a flow path 103a and a flow path 103b after passing through the second heat exchanger 16b downstream of the pump 17. The flow paths 103a and 103b merge with each other upstream of the flow control valve 18. The flow path 103a passes through the first heat exchanger 16a. On the other hand, the flow path 103b does not pass through the first heat exchanger 16a.

The switching valve 21 is a three-way valve. The switching valve 21 is provided at a connection portion between the upstream end of the flow path 103a and the upstream end of the flow path 103b. The switching valve 21 switches the path of ammonia in the ammonia flow path 103 between a state in which ammonia passes through the flow path 103a and a state in which ammonia passes through the flow path 103b. In the state in which ammonia passes through the flow path 103a, the ammonia sent from the ammonia tank 13 passes through the second heat exchanger 16b, then the first heat exchanger 16a, and is sent to the combustor 12. On the other hand, in the state in which ammonia passes through the flow path 103b, the ammonia sent from the ammonia tank 13 passes through the second heat exchanger 16b, then the first heat exchanger 16a, and is sent to the combustor 12 without passing through the first heat exchanger 16a.

As described above, the switching mechanism 20-1 switches the path of ammonia in the ammonia flow path 103 between a state in which ammonia passes through both the first heat exchanger 16a and the second heat exchanger 16b and a state in which ammonia passes only through the second heat exchanger 16b.

In the above, an example has been described in which the switching valve 21 is a three-way valve. However, the switching valve 21 does not have to be a three-way valve. For example, the switching valve 21, which is an on-off valve, may be provided in each of the flow paths 103a and 103b. In this case, by opening the switching valve 21 of the flow path 103a and closing the switching valve 21 of the flow path 103b, a state is achieved in which ammonia passes through the flow path 103a. On the other hand, by closing the switching valve 21 of the flow path 103a and opening the switching valve 21 of the flow path 103b, a state is achieved in which ammonia passes through the flow path 103b. Furthermore, in the switching mechanism 20-1, the number and connection positions of the branched portions of the ammonia flow path 103 are not particularly limited. In other words, in the switching mechanism 20-1, there are no particular limitations on how the ammonia flow path 103 branches.

The temperature sensor 22 detects the temperature of the ammonia that has passed through the second heat exchanger 16b and outputs the detection result to the control device 23. The temperature sensor 22 is provided, for example, in the ammonia flow path 103, between the second heat exchanger 16b and the switching valve 21.

The control device 23 includes a central processing unit (CPU), a ROM storing programs and the like, a RAM as a work area, etc. In the gas turbine system 1B, the control device 23 controls the operation of the switching valve 21. This allows the control device 23 to switch the path of the ammonia between a state in which the ammonia passes through both the first heat exchanger 16a and the second heat exchanger 16b and a state in which the ammonia passes only through the second heat exchanger 16b.

The control device 23 switches the ammonia path based on the state of ammonia in the ammonia flow path 103. In the example of Fig. 3, the control device 23 switches the ammonia path based on, for example, the temperature of the ammonia that has passed through the second heat exchanger 16b.

For example, when the temperature of the ammonia that has passed through the second heat exchanger 16b is equal to or lower than the reference temperature, the control device 23 controls the switching valve 21 so that the ammonia passes through the flow path 103a, thereby passing the ammonia through both the first heat exchanger 16a and the second heat exchanger 16b. On the other hand, when the temperature of the ammonia that has passed through the second heat exchanger 16b is higher than the reference temperature, the control device 23 controls the switching valve 21 so that the ammonia passes through the flow path 103b, thereby passing the ammonia only through the second heat exchanger 16b.

The reference temperature is an index for determining whether ammonia will vaporize when passed through the first heat exchanger 16a. If the temperature of ammonia that has passed through the second heat exchanger 16b is equal to or lower than the reference temperature, it can be determined that the ammonia will not vaporize even if passed through the first heat exchanger 16a. On the other hand, if the temperature of ammonia that has passed through the second heat exchanger 16b is higher than the reference temperature, it can be determined that the ammonia will vaporize when passed through the first heat exchanger 16a.

By switching the path of the ammonia as described above, the amount of heat recovered from the exhaust gas by the ammonia passing through the heat exchanger 16 can be maximized while suppressing vaporization of the ammonia.

In the above, an example has been described in which the switching mechanism 20-1 switches the ammonia path based on the temperature of the ammonia that has passed through the second heat exchanger 16b. However, the switching mechanism 20-1 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.

As described above, in the gas turbine system 1B, the heat exchanger 16 includes the first heat exchanger 16a and the second heat exchanger 16b disposed downstream of the first heat exchanger 16a in the exhaust flow path 102. The ammonia flow path 103 is provided with a switching mechanism 20-1 that switches the ammonia path between a plurality of states in which the heat exchangers 16 through which the ammonia passes are different from one another. This makes it possible to change the number or type of heat exchangers 16 through which the ammonia passes in the ammonia flow path 103. In the example of FIG. 3 , the number of heat exchangers 16 through which the ammonia passes can be changed. This makes it possible to adjust the degree of increase in the temperature of the ammonia due to heat exchange with the exhaust gas. This makes it possible to maximize the amount of heat recovered from the exhaust gas by the ammonia passing through the heat exchangers 16 while suppressing vaporization of the ammonia.

In particular, as described above, it is preferable that the switching mechanism 20-1 switches the path of the ammonia based on the state of the ammonia in the ammonia flow path 103. This makes it possible to appropriately adjust the degree of increase in the temperature of the ammonia due to heat exchange with the exhaust gas based on the state of the ammonia in the ammonia flow path 103. This appropriately realizes the amount of heat recovered from the exhaust gas by the ammonia passing through the heat exchanger 16 being maximized while suppressing the vaporization of the ammonia.

Fig. 4 is a schematic diagram showing the configuration of a gas turbine system 1C according to a third modified example. As shown in Fig. 4, the gas turbine system 1C according to the third modified example is provided with a first heat exchanger 16a and a second heat exchanger 16b as the heat exchanger 16, similar to the gas turbine system 1B described above. However, compared to the gas turbine system 1B described above, the gas turbine system 1C according to the third modified example is provided with a switching mechanism 20-2 that is different from the switching mechanism 20-1.

Similar to the switching mechanism 20-1 described above, the switching mechanism 20-2 switches the path of the ammonia between a plurality of states in which the heat exchanger 16 through which the ammonia passes is different. Compared to the switching mechanism 20-1 described above, the switching mechanism 20-2 has more branching points in the ammonia flow path 103. Furthermore, the switching mechanism 20-2 additionally includes a switching valve 24 and a flow rate sensor 25 compared to the switching mechanism 20-1 described above.

In the example of Fig. 4, the ammonia flow path 103 branches into a flow path 103c and a flow path 103d downstream of the pump 17. The flow paths 103c and 103d merge with each other upstream of the switching valve 21. The flow path 103c passes through the second heat exchanger 16b. On the other hand, the flow path 103d does not pass through the second heat exchanger 16b. As in the example of Fig. 3, the ammonia flow path 103 branches into a flow path 103a and a flow path 103b at the installation position of the switching valve 21. The flow path 103a passes through the first heat exchanger 16a. On the other hand, the flow path 103b does not pass through the first heat exchanger 16a.

Similar to the switching valve 21, the switching valve 24 is a three-way valve. The switching valve 24 is provided at a connection between the upstream end of the flow path 103c and the upstream end of the flow path 103d. The switching valve 24 switches the path of ammonia in the ammonia flow path 103 between a state in which ammonia passes through the flow path 103c and a state in which ammonia passes through the flow path 103d. When ammonia passes through the flow path 103c, the ammonia sent from the ammonia tank 13 passes through the second heat exchanger 16b and then is sent to the switching valve 21. On the other hand, when ammonia passes through the flow path 103d, the ammonia sent from the ammonia tank 13 is sent to the switching valve 21 without passing through the second heat exchanger 16b.

3 , the switching valve 21 switches the path of ammonia in the ammonia flow path 103 between a state in which ammonia passes through the flow path 103a and a state in which ammonia passes through the flow path 103b. In the state in which ammonia passes through the flow path 103a, the ammonia that has passed through the switching valve 21 passes through the first heat exchanger 16a and is sent to the combustor 12. On the other hand, in the state in which ammonia passes through the flow path 103b, the ammonia that has passed through the switching valve 21 is sent to the combustor 12 without passing through the first heat exchanger 16a.

As described above, the switching mechanism 20-2 switches the path of ammonia in the ammonia flow path 103 between a state in which ammonia passes through the first heat exchanger 16a and a state in which ammonia does not pass through the first heat exchanger 16a. The switching mechanism 20-2 also switches the path of ammonia in the ammonia flow path 103 between a state in which ammonia passes through the second heat exchanger 16b and a state in which ammonia does not pass through the second heat exchanger 16b. Therefore, the switching mechanism 20-2 can switch the path of ammonia between a state in which ammonia passes through both the first heat exchanger 16a and the second heat exchanger 16b, a state in which ammonia passes only through the first heat exchanger 16a, a state in which ammonia passes only through the second heat exchanger 16b, and a state in which ammonia does not pass through either the first heat exchanger 16a or the second heat exchanger 16b.

In the above, an example has been described in which the switching valve 24 is a three-way valve. However, like the switching valve 21 described above, the switching valve 24 does not have to be a three-way valve. For example, a switching valve 24 that is an on-off valve may be provided in each of the flow paths 103c and 103d. In this case, by opening the switching valve 24 for the flow path 103c and closing the switching valve 24 for the flow path 103d, ammonia flows through the flow path 103c. On the other hand, by closing the switching valve 24 for the flow path 103c and opening the switching valve 24 for the flow path 103d, ammonia flows through the flow path 103d. Furthermore, in the switching mechanism 20-2, the number and connection positions of the branched portions of the ammonia flow path 103 are not particularly limited. In other words, in the switching mechanism 20-2, there are no particular limitations on how the ammonia flow path 103 branches.

The flow rate sensor 25 detects the flow rate of ammonia in the ammonia flow path 103 and outputs the detection result to the control device 23. The flow rate sensor 25 is provided, for example, in the ammonia flow path 103, between the pump 17 and the switching valve 24.

In the gas turbine system 1C, the control device 23 controls the operations of the switching valves 21 and 24. As a result, the control device 23 can switch the path of the ammonia among a state in which the ammonia passes through both the first heat exchanger 16a and the second heat exchanger 16b, a state in which the ammonia passes only through the first heat exchanger 16a, a state in which the ammonia passes only through the second heat exchanger 16b, and a state in which the ammonia passes through neither the first heat exchanger 16a nor the second heat exchanger 16b.

Similar to the example of Fig. 3, the control device 23 switches the ammonia path based on the state of ammonia in the ammonia flow path 103. In the example of Fig. 4, for example, the control device 23 basically maintains a state in which ammonia is passed through the second heat exchanger 16b, and switches the ammonia path between a state in which ammonia passes through the first heat exchanger 16a and a state in which ammonia does not pass through the first heat exchanger 16a based on the temperature of the ammonia that has passed through the second heat exchanger 16b.

For example, when the temperature of the ammonia that has passed through the second heat exchanger 16b is equal to or lower than the reference temperature, the control device 23 controls the switching valve 21 so that the ammonia passes through the flow path 103a, thereby passing the ammonia through both the first heat exchanger 16a and the second heat exchanger 16b. On the other hand, when the temperature of the ammonia that has passed through the second heat exchanger 16b is higher than the reference temperature, the control device 23 controls the switching valve 21 so that the ammonia passes through the flow path 103b, thereby passing the ammonia only through the second heat exchanger 16b.

For example, when the temperature of the ammonia that has passed through the second heat exchanger 16b is higher than the reference temperature and the flow rate of the ammonia in the ammonia flow path 103 exceeds the reference flow rate, the control device 23 controls the switching valve 24 and the switching valve 21 so that the ammonia passes through the flow path 103d and the flow path 103b, respectively. As a result, a state is created in which the ammonia does not pass through either the first heat exchanger 16a or the second heat exchanger 16b.

The reference flow rate is an index for determining whether or not ammonia will vaporize when the temperature of the ammonia that has passed through the second heat exchanger 16b is higher than the reference temperature and the ammonia is made to pass only through the second heat exchanger 16b. When the temperature of the ammonia that has passed through the second heat exchanger 16b is higher than the reference temperature and the flow rate of the ammonia in the ammonia flow path 103 exceeds the reference flow rate, it can be determined that the ammonia will vaporize even when the ammonia is made to pass only through the second heat exchanger 16b.

By switching the path of the ammonia as described above, the amount of heat recovered from the exhaust gas by the ammonia passing through the heat exchanger 16 can be maximized while suppressing vaporization of the ammonia.

In the above, an example has been described in which the switching mechanism 20-2 switches the ammonia path based on two parameters: the temperature of the ammonia that has passed through the second heat exchanger 16b and the flow rate of ammonia in the ammonia flow path 103. However, the switching mechanism 20-2 may switch the ammonia path based on a parameter other than the above two parameters as a parameter indicating the state of ammonia in the ammonia flow path 103. For example, only one of the above two parameters 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 alone or in combination with another parameter as a parameter indicating the state of ammonia in the ammonia flow path 103.

In the above description, an example has been described in which the switching mechanism 20-2 switches the ammonia path between a state in which ammonia passes through both the first heat exchanger 16a and the second heat exchanger 16b, a state in which ammonia passes only through the second heat exchanger 16b, and a state in which ammonia passes through neither the first heat exchanger 16a nor the second heat exchanger 16b. However, the switching mechanism 20-2 may switch the ammonia path between a state in which ammonia passes only through the first heat exchanger 16a. For example, the degree of temperature increase of ammonia may differ between the first heat exchanger 16a and the second heat exchanger 16b. In this case, the switching mechanism 20-2 switches the ammonia path between a state in which ammonia passes only through the first heat exchanger 16a and a state in which ammonia passes only through the second heat exchanger 16b, 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 exhaust gas by ammonia passing through the heat exchanger 16 while suppressing vaporization of ammonia.

As described above, in the gas turbine system 1C, similarly to the above-described gas turbine system 1B, the heat exchanger 16 includes the first heat exchanger 16a and the second heat exchanger 16b that is disposed downstream of the first heat exchanger 16a in the exhaust flow path 102. The ammonia flow path 103 is provided with a switching mechanism 20-2 that switches the ammonia path between a plurality of states in which the heat exchanger 16 through which the ammonia passes is different from one another. Therefore, the same effects as those of the above-described gas turbine system 1B are achieved.

3 and 4 , an example in which two heat exchangers 16 are provided in the exhaust flow path 102 has been described. However, three or more heat exchangers 16 may be provided in the exhaust flow path 102. When multiple heat exchangers 16 are provided in the exhaust flow path 102, a heat medium flow path 105 may be interposed between the exhaust flow path 102 and the ammonia flow path 103 in each heat exchanger 16, as in the gas turbine system 1A described above.

In the above, the switching mechanisms 20-1 and 20-2 have been described as examples of switching mechanisms that switch the ammonia path. However, the switching mechanisms are not limited to these examples. For example, the flow path 103b and the switching valve 21 may be omitted from the example of FIG. 4. In this case, the ammonia path can be switched between a state in which ammonia passes through both the first heat exchanger 16a and the second heat exchanger 16b and a state in which ammonia passes only through the first heat exchanger 16a.

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.

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

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

1: Gas turbine system 1A: Gas turbine system 1B: Gas turbine system 1C: Gas turbine system 12: Combustor 13: Ammonia tank 14: Boiler 16: Heat exchanger 16a: First heat exchanger 16b: Second heat exchanger 20-1: Switching mechanism 20-2: Switching mechanism 102: Exhaust flow path 103: Ammonia flow path 105: Heat medium flow path

Claims (4)

an ammonia tank in which ammonia is stored in a liquid state;
a combustor connected to the ammonia tank and supplied with the ammonia in a liquid state;
an exhaust flow path connected to the combustor;
a boiler provided in the exhaust flow path;
a heat exchanger that is disposed in the exhaust passage downstream of the boiler and through which an ammonia passage that connects the ammonia tank and the combustor passes;
Equipped with
In the heat exchanger, the ammonia is heated to a degree that does not vaporize.
Gas turbine systems. In the heat exchanger, a heat medium flow path is interposed between the exhaust flow path and the ammonia flow path.
The gas turbine system of claim 1 . the heat exchanger includes a first heat exchanger and a second heat exchanger disposed downstream of the first heat exchanger in the exhaust flow path,
The ammonia flow path is provided with a switching mechanism that switches the path of the ammonia so as to switch which of the heat exchangers the ammonia passes through .
The gas turbine system according to claim 1 or 2. the switching mechanism switches the path of the ammonia based on at least one of a temperature, a flow rate, and a pressure of the ammonia in the ammonia flow path.
The gas turbine system of claim 3 .