WO2024252860A1 - Composite power generation system and composite power generation method - Google Patents

Abstract

A composite power generation system (1A) generates first power by steam in a first power generation facility (2) and converts liquid ammonia into a turbine drive fluid in a second power generation facility (3) using a part of the steam, drives an ammonia turbine (20) to generate second power, burns exhaust ammonia gas discharged from the second power generation facility (3), and uses the combustion heat. The turbine drive fluid is a supercritical fluid of ammonia or superheated ammonia gas obtained by heating liquid ammonia in an energy addition facility (16) of the second power generation facility (3).

Description

Combined power generation system and combined power generation method

The present invention relates to a combined power generation system and method that can reduce or eliminate energy loss when vaporizing liquid ammonia to produce ammonia gas for combustion.

Generally, ammonia (NH ₃ ) is a gas at room temperature (20° C., 0.875 MPaG (vapor pressure)), but can be easily liquefied by cooling or pressurization, and when used as a fuel, it can be transported and stored in liquid form. This allows for reduced costs for transportation and storage compared to handling gaseous fuels that cannot be easily liquefied. Furthermore, in recent years, ammonia has been attracting attention as a fuel that does not emit carbon dioxide (CO ₂ ), a greenhouse gas, when burned.
For this reason, in conventional thermal power plants that use fossil fuels such as coal, attempts have been made to reduce emissions of carbon dioxide, a greenhouse gas, by using ammonia as part of the fuel.
On the other hand, when ammonia is used as fuel, liquid ammonia needs to be vaporized to form ammonia gas.

The boiling point of ammonia is -33.34°C, which is significantly lower than that of water. Therefore, when vaporizing liquid ammonia, it can be easily vaporized by using industrial water or seawater as a heat medium.
On the other hand, if industrial water or seawater is used as a heat medium for vaporizing liquid ammonia, the energy costs required for pumping the water are expected to increase, and there was concern that the cost benefits of using ammonia as fuel would be diminished from the perspective of energy balance.
In view of these circumstances, liquid ammonia has been vaporized using residual heat generated in conventional thermal power plants and the like and used as fuel.
As a prior application in this technical field, for example, "Ammonia supply unit for power plant, ammonia vaporization treatment method for power plant, and power plant" disclosed in Patent Document 1 is known.

JP 2023-11172 A

According to the invention disclosed in the above-mentioned Patent Document 1, by using exhaust heat generated in conventional thermal power plants or the like, ammonia gas for combustion can be produced while minimizing energy loss during vaporization, but the amount of exhaust heat available in thermal power plants or the like is limited.
For this reason, when Patent Document 1 is taken into consideration, there is a limit to the amount of liquid ammonia that can be vaporized.

The present invention was made to address these conventional problems, and its purpose is to provide a combined power generation system and method capable of vaporizing a large amount of liquid ammonia to generate ammonia gas for combustion, while reducing or eliminating the energy loss caused by vaporization.

A combined cycle power generation system as a first invention for solving the above problems comprises a first power generation facility having a boiler facility for generating steam, a steam turbine driven by the steam, and a first generator connected to the steam turbine for generating power, a storage facility for storing liquid ammonia, an energy addition facility for converting the liquid ammonia supplied from the storage facility into a turbine driving fluid by using residual heat of exhaust steam from the steam turbine, an ammonia turbine driven by the turbine driving fluid generated in the energy addition facility, and a second power generation facility having a second generator connected to the ammonia turbine for generating power, and is characterized in that the exhaust ammonia gas is combusted in the boiler facility, or in at least one arbitrary facility other than the boiler facility, which has a combustion section capable of combusting exhaust ammonia gas discharged from the ammonia turbine.
In the first invention having the above configuration, the first power generation facility has the effect of driving a steam turbine with steam generated in the boiler equipment, and generating first electricity with a first generator connected to this steam turbine.
The energy addition equipment of the second power generation facility has an effect of generating a turbine driving fluid (superheated ammonia gas or ammonia supercritical fluid) from liquid ammonia supplied from the storage facility by utilizing residual heat of exhaust steam from the steam turbine of the first power generation facility. Furthermore, the second power generation facility has an effect of driving an ammonia turbine with the turbine driving fluid generated in the energy addition equipment, and generating second electricity with a second generator connected to the ammonia turbine.
Furthermore, the waste ammonia gas discharged from the ammonia turbine of the second power generation facility is used as ammonia gas for combustion in the boiler facility or in at least one optional facility other than the boiler facility.
In other words, in the first invention, a first electric power is generated using steam in a first power generation facility, while a turbine driving fluid is produced in a second power generation facility using a portion of this steam to generate a second electric power, and further, exhaust ammonia gas discharged from the second power generation facility is used as fuel.

A second invention is the above-mentioned first invention, characterized in that the exhaust ammonia gas is combusted in a boiler facility.
In the second invention having the above configuration, the equipment for combusting the exhaust ammonia gas discharged from the ammonia turbine is specified to be a boiler equipment. Therefore, the operation of the second invention is the same as that of the first invention.
In addition, in the second invention, by using the exhaust ammonia gas discharged from the ammonia turbine as fuel for the boiler equipment, it has the effect of reducing the amount of carbon dioxide emissions when generating the first electric power in the first power generation facility.

A third invention is the above-mentioned first or second invention, characterized in that it further comprises a pressurizing facility for pressurizing the liquid ammonia to be supplied to the energy addition facility to 6 MPaG or more.
The third invention having the above configuration has the same effect as the first or second invention. Furthermore, the third invention has the effect of increasing the total amount of power generation in the first and second power generation facilities by pressurizing the liquid ammonia to be supplied to the energy-adding equipment to 6 MPaG or more, compared to the case where unpressurized liquid ammonia is used.

A fourth invention is the first or second invention described above, wherein the steam turbine comprises a medium-pressure steam turbine that discharges medium-pressure exhaust steam having an outlet temperature of 200 to 450 ° C., and a low-pressure steam turbine that discharges low-pressure exhaust steam having an outlet temperature of 30 to 200 ° C., and the energy-adding equipment is an ammonia vaporization equipment, and comprises a preheater that preheats liquid ammonia, a vaporizer that vaporizes the liquid ammonia preheated in the preheater, and a superheater that superheats the ammonia gas vaporized in the vaporizer, and is characterized in that it comprises a medium-pressure exhaust steam supply line that supplies a portion of the medium-pressure exhaust steam to the superheater and a portion of the medium-pressure exhaust steam that has been reduced in temperature in the superheater to the vaporizer, and a hot water supply line that supplies the first hot water generated from the vaporizer or its related equipment and/or the second hot water generated from the related equipment of the low-pressure steam turbine to the preheater.
The fourth invention having the above configuration has the same effect as the first or second invention. In addition, in the fourth invention, the superheater of the ammonia vaporization equipment uses medium-pressure exhaust steam to superheat the ammonia gas vaporized in the vaporizer, and supplies a portion of the medium-pressure exhaust steam used in the superheater to the vaporizer (=medium-pressure exhaust steam supply line) to use it for vaporizing liquid ammonia, thereby efficiently generating superheated ammonia gas.
In addition, in the fourth invention, the first hot water generated from the vaporizer or its associated equipment and/or the second hot water generated from the associated equipment of the low-pressure steam turbine is used (=hot water supply line) to preheat the liquid ammonia fed to the preheater, thereby effectively utilizing the residual heat of the vaporizer or its associated equipment and/or the exhaust heat generated from the low-pressure steam turbine to efficiently preheat the liquid ammonia.
In particular, since the fourth invention is provided with a hot water supply line, the amount of waste heat released into the environment can be reduced.

A fifth invention is the above-mentioned first invention, characterized in that the exhaust ammonia gas is supplied to a boiler facility or any facility by using the residual pressure of the exhaust ammonia gas discharged from the ammonia turbine.
The fifth aspect of the invention has the same effect as that of the first aspect of the invention. In addition, the fifth aspect of the invention does not require a supply facility for supplying exhaust ammonia gas to a boiler facility or any other facility.

A sixth invention is the above-mentioned first invention, characterized in that the liquid ammonia contains 1 mass % or less of water.
The sixth invention having the above configuration has the same effect as the first invention. In addition, the sixth invention has an effect of suppressing stress corrosion cracking of steel, particularly when steel is used as the material for the supply pipes for liquid ammonia or ammonia gas in the second power generation facility.

A seventh invention is the sixth invention, characterized in that the temperature of the exhaust ammonia gas supplied to the combustion section of the boiler facility or any facility is 18.8° C. or higher.
The seventh invention having the above-mentioned configuration has the same effect as the sixth invention. In addition, the seventh invention has the effect of preventing condensation from occurring on the surface of the combustion part through which the exhaust ammonia gas passes, particularly under atmospheric pressure, by setting the temperature of the exhaust ammonia gas supplied to the combustion part of the boiler equipment or any equipment to 18.8°C or higher.
In this case, condensation occurs on the surface of the steel material that comes into contact with the exhaust ammonia gas in the combustion section, and this has the effect of suppressing corrosion of the steel material caused by the condensed water.

A combined cycle power generation method according to an eighth aspect of the present invention is characterized in that a steam turbine connected to a first generator is driven by steam generated in a boiler facility to generate first electric power, a turbine driving fluid is generated from liquid ammonia using residual heat of exhaust steam from the steam turbine, an ammonia turbine connected to a second generator is driven by the turbine driving fluid to generate second electric power, and exhaust ammonia gas discharged from the ammonia turbine is combusted in the boiler facility or at least one arbitrary facility other than the boiler facility.
The eighth invention having the above-mentioned configuration specifies the above-mentioned first invention as a method invention, and the action of the eighth invention is the same as the action of the first invention.

According to the first invention as described above, a portion of the steam (heat) generated for power generation in the first power generation facility can be utilized to vaporize a large amount of liquid ammonia to be used for combustion.
In addition, according to the first invention, by using ammonia gas (exhaust ammonia gas) as at least a part of the fuel for obtaining thermal energy in a boiler facility or any facility, it is possible to reduce the amount of carbon dioxide emissions when obtaining thermal energy by combustion.
Furthermore, according to the first invention, a part of the steam (heat) used for power generation at the first power generation facility can be diverted as a heat source for vaporizing a large amount of liquid ammonia, and a part or all of the reduction in the amount of power generated from the first power generation facility can be compensated for by the generation of the second power generation facility.
Therefore, according to the first invention, by using the first power generation facility and the second power generation facility in combination, it is possible to reduce or eliminate energy loss when vaporizing a large amount of liquid ammonia.

The second invention provides the same effects as the first invention described above. Furthermore, the second invention can reduce carbon dioxide emissions when generating the first electric power in the first power generation facility, compared to when only fossil fuels are used as fuel.

According to the third invention, the same effects as those of the first or second invention described above can be achieved. In addition, according to the third invention, by pressurizing liquid ammonia to a specific pressure or higher, the amount of exhaust steam extracted from the first power generation facility to generate the turbine driving fluid can be reduced compared to the case where the turbine driving fluid is generated using unpressurized liquid ammonia.
Therefore, according to the third aspect of the present invention, the thermal energy diverted from the first power generation facility can be efficiently converted into electrical energy in the second power generation facility.

According to the fourth invention, the same effect as that of the first or second invention is obtained. In addition, according to the fourth invention, the residual heat of the medium-pressure exhaust steam is supplied to the superheating of ammonia gas (heater) and the vaporization of liquid ammonia (vaporizer) in this order, and the residual heat of the medium-pressure exhaust steam used in the vaporizer and/or the exhaust heat generated from the related equipment of the low-pressure steam turbine is used to preheat the liquid ammonia (preheater), thereby minimizing the loss of thermal energy used to generate superheated ammonia gas.
As a result, according to the fourth aspect of the present invention, the thermal energy diverted from the first power generation facility can be effectively utilized for generating the second electric power in the second power generation facility.

The fifth invention provides the same effects as the first invention described above. In addition, the fifth invention does not require a separate supply facility for supplying exhaust ammonia gas to the boiler facility or any other facility, so the facility structure of the fifth invention can be simplified. Furthermore, the fifth invention does not require a supply facility for supplying exhaust ammonia gas, so the costs required for its operation and maintenance can be reduced. Therefore, the fifth invention can reduce the costs of generating the first and second electric power.

According to the sixth aspect of the present invention, the same effects as those of the first aspect of the present invention can be obtained. In addition, according to the sixth aspect of the present invention, the risk of damage to the ammonia feed pipe in the second power generation facility can be reduced compared to a case where the ammonia does not contain water.
Therefore, according to the sixth aspect of the present invention, it is possible to reduce costs required for repair and maintenance of the second power generation facility. As a result, according to the sixth aspect of the present invention, it is possible to reduce costs, particularly when generating the second electric power.

According to the seventh aspect of the present invention, the same effects as those of the sixth aspect of the present invention can be obtained. In addition, according to the seventh aspect of the present invention, it is possible to suppress deterioration or damage caused by corrosion or the like of the combustion part of the boiler equipment or any equipment due to condensed water.
Therefore, according to the seventh invention, it is possible to reduce the cost required for repair and maintenance of the boiler equipment or any equipment. As a result, according to the seventh invention, it is possible to reduce the cost of operating the equipment that combusts the exhaust ammonia gas.

The eighth invention specifies the above-mentioned first invention as a method invention, and the effects of the eighth invention are the same as those of the first invention.
In other words, according to the eighth invention, the reduction in the amount of generated first electricity caused by diverting a portion of the thermal energy used to generate the first electricity to generate a large amount of ammonia gas (exhaust ammonia gas) for combustion can be compensated for by generating the second electricity using the turbine driving fluid (superheated ammonia gas or supercritical ammonia fluid).
As a result, according to the eighth aspect of the present invention, it is possible to reduce or eliminate the energy loss that occurs when ammonia is vaporized and used as fuel.

1 is a system configuration diagram of a combined power generation system according to an embodiment of the present invention. FIG. 11 is a system configuration diagram of a combined power generation system according to a modified example. 1 is a graph showing changes in specific enthalpy when the pressure of various gases is changed. This figure shows the assumptions regarding the thermodynamic properties of the heat source steam (exhaust steam) and the ammonia gas after vaporization used to estimate the exergy change. 1 is a graph showing the relationship between the exergy or power required to vaporize ammonia and the pressure of the vaporized ammonia. FIG. 1 is a diagram showing an outline of a simplified model of a thermal power generation facility common to Comparative Examples 1 and 2 and Examples 1 to 3. FIG. 1 is a diagram showing an overview of a simulation model of Comparative Example 1. FIG. 13 is a diagram showing an outline of a simulation model of Comparative Example 2. FIG. 1 is a diagram showing an overview of a simulation model of a first embodiment. FIG. 13 is a diagram showing an outline of a simulation model of a second embodiment. FIG. 13 is a diagram showing an outline of a simulation model of a third embodiment. 1 is a graph showing the amount of steam required to produce 1 ton of ammonia gas in each simulation model of Comparative Examples 1 and 2 and Examples 1 to 3. 1 is a graph showing the specific exergy of each fluid. 1 is a graph showing the estimated results of the total power generation amount in each simulation model of Comparative Examples 1 and 2 and Examples 1 to 3. 1 is a graph showing the estimated results of exergy balance per ton of ammonia gas in each simulation model of Comparative Examples 1 and 2 and Examples 1 to 3.

The combined power generation system and method according to an embodiment of the present invention will be described in detail with reference to Figures 1 to 4B.

[1-1: Basic configuration of the present invention]
First, a combined power generation system according to a representative embodiment of the present invention (hereinafter, referred to as this embodiment) will be described with reference to FIG.
FIG. 1 is a system configuration diagram of a combined power generation system according to this embodiment.
As shown in FIG. 1, the combined power generation system 1A according to this embodiment includes a first power generation facility 2 that generates a first electric power by utilizing water vapor (hereinafter, simply referred to as "steam"), and a second power generation facility 3 that vaporizes liquid ammonia by utilizing residual heat of the steam generated in the first power generation facility 2 to generate the first electric power, and generates a second electric power by utilizing the vaporized ammonia gas, and is further characterized in that exhaust ammonia gas discharged from the second power generation facility 3 is combusted in a boiler facility 4 of the first power generation facility 2.

Further, the first power generation facility 2 in the combined power generation system 1A according to this embodiment as described above can be, for example, a conventional thermal power generation facility that can be directly converted.
More specifically, the first power generation facility 2 in the combined power generation system 1A of this embodiment includes a boiler equipment 4 that generates steam, a steam turbine 8 (e.g., a high-pressure steam turbine 8a, an intermediate-pressure steam turbine 8b, and a low-pressure steam turbine 8c) driven by steam generated in the boiler equipment 4, and a first generator 9 connected to the steam turbine 8 to generate electricity.
The above-mentioned first power generation facility 2 further includes a steam supply pipe _Lw (hereinafter simply referred to as "piping _Lw ") for supplying steam (heat medium) generated in the boiler equipment 4, pumps _P1 to _P3 as a power source for circulating the steam (heat medium) in this pipe _Lw , heat exchangers 12 and 13 including a condenser 11, and related equipment or devices such as a deaerator 14 and water supply equipment 10, at desired locations on the pipe _Lw .
The deaerator 14 is a device for removing gases such as oxygen and carbon dioxide present in the heat medium (water) used to operate the steam turbine 8 .

Furthermore, the second power generation facility 3 in the combined power generation system 1A according to this embodiment includes a storage facility 15 for storing liquid ammonia, an ammonia vaporization facility 16 (energy addition facility) for vaporizing the liquid ammonia supplied from this storage facility 15 by utilizing residual heat of exhaust steam discharged from the steam turbine 8 in the first power generation facility 2, an ammonia turbine 20 driven by ammonia gas (superheated ammonia gas) which is the turbine driving fluid produced in this ammonia vaporization facility 16, and a second generator 21 connected to this ammonia turbine 20 for generating second electricity.
In the above-mentioned second power generation facility 3, ammonia (liquid ammonia and ammonia gas) is fed through an ammonia feed line _La consisting of an independent pipe separate from the above-mentioned pipe _Lw .

The boiler facility 4 of the first power generation facility 2 includes a combustion unit 5. Furthermore, this combustion unit 5 is supplied with fuel (e.g., fossil fuels such as natural gas, coal, and oil, and combustible waste, etc.) from a fuel supply device 6, and is also supplied with exhaust ammonia gas discharged from the ammonia turbine 20 in the second power generation facility 3 as fuel.
In the combustion section 5 of the boiler facility 4 shown in FIG. 1 , a case has been described as an example in which the fuel supplied from the fuel supply device 6 and the exhaust ammonia gas discharged from the ammonia turbine 20 are mixed and burned, but the fuel supplied to the combustion section 5 may be only the exhaust ammonia gas.

In the boiler equipment 4 of the first power generation facility 2, steam is generated in a steam generator 7 (e.g., a steam generator 7a or a steam generator (reheater) 7b, etc.) by heat generated in the combustion section 5, and this steam is used to operate a steam turbine 8.
In addition, a part of the exhaust steam discharged from the steam turbine 8 in the first power generation facility 2 may be extracted outside the first power generation facility 2 and used in equipment (not shown) of another facility (optional component). Note that the symbols X to Z in Fig. 1 indicate that a part of the exhaust steam discharged from the steam turbine 8 is guided outside the first power generation facility 2 and used for another purpose.
In other words, the first power generation facility 2 in the combined power generation system 1A according to this embodiment may constitute a part of a chemical plant.

The power generation method (steam turbine method) of the first power generation facility 2 in the combined power generation system 1A according to this embodiment does not have to be limited to the method combining the extraction condensation type and the reheat type shown in FIG. 1, but may be a method adopting any one of these types or any of the methods described below.
(1) Back pressure type (2) Condensate type (3) Extraction back pressure type

Furthermore, when the combined power generation system 1A according to this embodiment shown in FIG. 1 is specified as a method invention, it is a combined power generation method in which, for example, a steam turbine 8 connected to a first generator 9 is driven by steam generated in a boiler facility 4 to generate first electricity, ammonia gas, which is a turbine driving fluid, is generated from liquid ammonia using residual heat of the exhaust steam from this steam turbine 8, an ammonia turbine 20 connected to a second generator 21 is driven by ammonia gas to generate second electricity, and the exhaust ammonia gas discharged from the ammonia turbine 20 is combusted in the boiler facility 4.

[1-2: Actions and Effects of the Basic Configuration of the Present Invention]
According to the combined power generation system 1A (or combined power generation method) of this embodiment as described above, a portion of the heat (waste heat of steam) used to operate the steam turbine 8 in the first power generation facility 2, that is, a portion of the medium-pressure exhaust steam discharged from the medium-pressure steam turbine 8b, is supplied to the ammonia vaporization equipment 16 of the second power generation facility 3 to vaporize (and superheat) liquid ammonia, thereby efficiently producing a large amount of ammonia gas for combustion.
Furthermore, by using the exhaust ammonia gas discharged from the ammonia turbine 20 as fuel in the boiler equipment 4 of the first power generation facility 2, it is possible to reduce the amount of carbon dioxide emissions compared to the case where only fuel that emits carbon dioxide is burned in the boiler equipment 4.
Furthermore, in the combined power generation system 1A (or the combined power generation method) according to this embodiment, a part of the steam used to operate the steam turbine 8 is diverted as a heat medium for vaporizing the liquid ammonia. Therefore, in the combined power generation system 1A according to this embodiment, the thermal energy supplied to the steam turbine 8 is reduced, which reduces the amount of generated first electric power.
On the other hand, in the combined power generation system 1A (or the combined power generation method) according to this embodiment, the ammonia gas vaporized in the ammonia vaporization facility 16 of the second power generation facility 3 is further superheated, and the ammonia turbine 20 is operated using this superheated ammonia gas (turbine driving fluid) to generate second electricity.
As a result, in the combined power generation system 1A (or combined power generation method) of this embodiment, part or all of the reduction in output of the first power at the first power generation facility 2 can be compensated for by the second power generation at the second power generation facility 3.
As a result, according to the combined power generation system 1A (or combined power generation method) of this embodiment, by using the first power generation facility 2 and the second power generation facility 3 in combination, it is possible to reduce or eliminate energy loss when vaporizing liquid ammonia to obtain a large amount of ammonia gas for combustion (exhaust ammonia gas).

[2-1: Modifications of the present invention]
Next, a combined power generating system according to a modified example of this embodiment (hereinafter simply referred to as a "modified combined power generating system") will be described with reference to FIG.
Fig. 2 is a system configuration diagram of a combined power generation system according to a modified example. Note that the same parts as those shown in Fig. 1 are given the same reference numerals, and the description of the configuration will be omitted.
In the combined power generation system 1A according to the present embodiment described above, the exhaust ammonia gas discharged from the ammonia turbine 20 is combusted in the boiler equipment 4 of the first power generation facility 2. However, the place where the exhaust ammonia gas is combusted is not necessarily the boiler equipment 4.
In other words, the combined power generation system 1B according to the modified example is characterized in that the exhaust ammonia gas discharged from the ammonia turbine 20 of the first power generation facility 2 is combusted in the combustion section 23 of any equipment 22 other than the boiler equipment 4.

Note that the optional facility 22 in the combined power generation system 1B according to the modified example shown in FIG. 2 may be, for example, the following facility.
- Other boiler equipment that burns exhaust ammonia gas alone or in combination with other fuels - Incinerators that use exhaust ammonia gas - Equipment for utilizing the combustion heat of exhaust ammonia gas for heat treatment, etc. in other plants, etc.

In addition, in the combined power generation system 1B according to the modified example shown in FIG. 2 , the case where the optional facility 22 is one has been described as an example, but the exhaust ammonia gas discharged from the ammonia turbine 20 may be supplied as fuel to two or more optional facilities 22 depending on the scale of the first power generation facility 2 or the like (optional component).
Furthermore, although not specifically shown, the combined power generation system 1B according to a modified example may supply exhaust ammonia gas discharged from the ammonia turbine 20 not only to at least one optional equipment 22 but also to the combustion section 5 in the boiler equipment 4 of the first power generation facility 2 (optional component).
In addition, the first power generation facility 2 in the combined power generation system 1B according to the modified example shown in Fig. 2 does not need to be a power generation facility similar to a conventional thermal power generation facility, and may be, for example, a conventional nuclear power generation facility (optional component). In this case, ammonia gas for combustion (exhaust ammonia gas) generated in the second power generation facility 3 is combusted in at least one optional facility 22.

Furthermore, when the combined power generation system 1B according to the modified example shown in FIG. 2 is specified as a method invention, it is a combined power generation method in which a steam turbine 8 connected to a first generator 9 is driven by steam generated in a boiler facility 4 to generate first electricity, ammonia gas, which is a turbine driving fluid, is generated from liquid ammonia using residual heat of exhaust steam from the steam turbine 8, an ammonia turbine 20 connected to a second generator 21 is driven by ammonia gas to generate second electricity, and exhaust ammonia gas discharged from the ammonia turbine 20 is combusted in the boiler facility 4 or at least one optional facility other than the boiler facility 4 (for example, optional facility 22).

[2-2: Effects and advantages of the modified examples of the present invention]
The combined power generation system 1B according to the above-mentioned modified example (or the combined power generation method according to the modified example) has the same effects as those of the combined power generation system 1A (or the combined power generation method) described in [1-2] above. In addition to these effects, there is an additional effect that the exhaust ammonia gas discharged from the ammonia turbine 20 can be effectively utilized as fuel for obtaining combustion heat in the boiler facility 4 and/or at least one optional facility 22.
Furthermore, according to the modified combined power generation system 1B (or the modified combined power generation method), the amount of carbon dioxide emitted from the boiler equipment 4 and/or the at least one optional piece of equipment 22 can be reduced compared to the case where only fuel that emits carbon dioxide is burned in the combustion section 5 of the boiler equipment 4 and/or the combustion section 23 of at least one optional piece of equipment 22.

[3; Optional additional items of the combined power generation system related to the basic configuration and modified examples]
Hereinafter, configurations (optional additional items) that are common to the combined power generation system 1A according to this embodiment and the combined power generation system 1B according to the modified example and that can be added as necessary will be described.
Furthermore, the combined power generation system 1A according to this embodiment or the combined power generation system 1B according to the modified example may include each of the optional additional items described below alone, or may include a combination of a plurality of desired items.

<3-1: Method of supplying exhaust ammonia gas to the combustion section>
The exhaust ammonia gas may be supplied to the combustion section 5 of the boiler equipment 4 shown in FIG. 1 and FIG. 2 or the combustion section 23 of the optional equipment 22 shown in FIG. 2 by using the residual pressure of the exhaust ammonia gas discharged from the ammonia turbine 20 (optional component).
In this case, there is no need to separately provide a gas supply device such as a blower to supply the exhaust ammonia gas discharged from the ammonia turbine 20 to the combustion section 5 and the combustion section 23 .
As a result, the facility configuration of the combined power generation system 1A according to this embodiment or the combined power generation system 1B according to the modified example can be simplified, and the costs required for maintenance thereof can be reduced.

<3-2-1: About adding water to ammonia>
The liquid ammonia, which is supplied from the storage facility 15 shown in Figures 1 and 2 and is the heat medium that runs the ammonia turbine 20, may contain up to 1 mass % water (optional component).
In this case, when the equipment constituting the ammonia feed line _La and the ammonia vaporization facility 16 in the first power generation facility 2 is made of steel, it is possible to suppress the occurrence of stress corrosion cracking of the steel.
As a result, it is possible to reduce the cost required for maintenance and repair of the second power generation facility 3. This makes it possible to reduce the cost required for generating the second electric power in the second power generation facility 3.

<3-2-2: Temperature of exhaust ammonia gas in the combustion section>
In particular, when liquid ammonia, which is a heat medium for operating the ammonia turbine 20, contains 1 mass % or less of water, the temperature of the ammonia gas (exhaust ammonia gas) supplied to the combustion section 5 of the boiler equipment 4 shown in FIGS. 1 and 2 or the combustion section 23 of the optional equipment 22 shown in FIG. 2 may be set to 18.8° C. or higher (optional component).
In this case, it is possible to prevent water in the ammonia gas (exhaust ammonia gas) from condensing under atmospheric pressure, thereby making it possible to suppress corrosion of the steel material constituting the ammonia feed line _La (see FIG. 1 or FIG. 2) in the second power generation facility 3 and the steel material constituting, for example, the burner of the combustion unit 5 or the combustion unit 23, caused by condensed water.
This also makes it possible to reduce the costs required for maintenance and repair of the second power generation facility 3. This makes it possible to reduce the costs incurred when generating the second electric power in the second power generation facility 3.

<3-3: Liquid ammonia pressurization equipment>
As shown in FIGS. 1 and 2, the second power generation facility 3 may include a pressurizing facility P ₄ (e.g., a pump) that pressurizes the liquid ammonia to be supplied to the ammonia vaporization facility 16 to 6 MPaG or more (optional component).
In this case, the thermal energy required to generate superheated ammonia gas can be reduced compared to the case of vaporizing and superheating unpressurized liquid ammonia. In other words, the amount of exhaust steam extracted from the steam turbine 8 of the first power generation facility 2 to vaporize and superheat ammonia in the second power generation facility 3 can be reduced.
The reason for this is explained below.

Figure 3 is a graph showing the change in specific enthalpy when the pressure of various gases is changed. The specific enthalpy of various gases shown in Figure 3 was estimated using "REFPROP Version 10" of the National Institute of Standards and Technology (NSIT).
As shown in Fig. 3, the specific enthalpy of ammonia ( _NH3 ), water ( _H2O ), methanol, and ethanol tended to depend on pressure. In other words, the specific enthalpy of polar molecules such as ammonia has pressure dependence.
Therefore, in the combined power generation system 1A according to this embodiment or the combined power generation system 1B according to the modified example, by pressurizing liquid ammonia to a pressure close to the critical pressure when vaporizing it, it is possible to reduce the thermal energy required for vaporization, i.e., the amount of exhaust steam extracted from the first power generation facility 2, compared to the case of vaporizing unpressurized ammonia.
In addition, liquid ammonia undergoes a smaller volume change when pressurized than ammonia gas, so the amount of power energy required to pressurize liquid ammonia is less than that required to pressurize ammonia gas.
In other words, in the ammonia vaporization equipment 16 shown in FIG. 1 or FIG. 2 , by arranging the pressurizing equipment _P4 on the upstream side of the vaporizer 18, it is possible to reduce the power energy required to pressurize the ammonia, compared to the case where the pressurizing equipment _P4 is provided on the downstream side of the vaporizer 18.

Next, the reason why the pressure of the liquid ammonia supplied to the ammonia vaporization facility 16 is set to 6 MPaG or more will be described.
Generally, in power generation using a steam turbine (e.g., steam turbine 8) in a thermal power generation facility (e.g., first power generation facility 2) or the like, the energy generated in a boiler facility (e.g., boiler facility 4) is separated into (i) electrical energy generated by the mechanical work of expansion, and (ii) thermal energy discarded to cooling water.
In addition, the total energy of the steam supplied to the inlet of a steam turbine (e.g., the steam turbine 8) in a thermal power generation facility (e.g., the first power generation facility 2) is a combination of the above-mentioned (i) electrical energy and (ii) thermal energy, and is generally referred to as "enthalpy (H)."
Furthermore, the enthalpy (H) is defined by the following (Equation 1).

(Equation 1)
・Enthalpy (H) = Internal Energy (U) + Work (PV)
= heat energy + work

Furthermore, the maximum work that can be obtained until steam with temperature (T) and pressure (P) reaches a reference environmental state defined by an arbitrary temperature _T0 and an arbitrary pressure _P0 is the "physical exergy (E _ph )" (hereinafter simply referred to as "exergy"), which can be calculated by the following (Equation 2).

(Equation 2)
・E _ph = H−H ₀ −T ₀ (S−S ₀ )
Where, H: enthalpy, S: entropy
In addition, in power generation using a steam turbine (e.g., steam turbine 8) in a thermal power generation facility (e.g., first power generation facility 2) or the like, the exergy obtained from the thermal power generation facility (e.g., first power generation facility 2) or the like is the maximum work (electrical energy) that can be extracted from the energy of steam supplied to the inlet of the steam turbine (e.g., steam turbine 8) before this steam reaches an arbitrary reference environmental state.

Here, in the combined power generation system 1A according to this embodiment or the combined power generation system 1B according to the modified example, when the steam (exhaust steam) discharged from the steam turbine 8 of the first power generation facility 2 is used to vaporize liquid ammonia, which is the heat medium of the second power generation facility 3, the exergy change of the steam (exhaust steam) extracted from the first power generation facility 2 and the vaporized ammonia (ammonia gas) generated in the second power generation facility 3 will be considered.
FIG. 4A is a diagram showing preconditions for the thermodynamic properties of steam (exhaust steam) as a heat source used in estimating the exergy change shown in FIG. 4B and ammonia gas after vaporization.
Fig. 4B is a graph showing the relationship between the exergy or power required for vaporizing liquid ammonia and the pressure of the vaporized ammonia. The thermodynamic properties of the steam (exhaust steam) and ammonia shown in Fig. 4A were also estimated using "REFPROP Version 10" by the National Institute of Standards and Technology (NSIT).
In the graph of FIG. 4B, "Curve 1" indicates the exergy change of the exhaust steam supplied from the steam turbine 8 of the first power generation facility 2 to the ammonia vaporization facility 16 of the second power generation facility 3, "Curve 2" indicates the exergy change of the vaporized ammonia (ammonia gas), "Line 1" indicates the change in the required power of the pressurization facility P ₄ (e.g., a pump) that pressurizes the liquid ammonia, and "Line 2" indicates the critical pressure of ammonia. In addition, "Curve 3" shown in the graph of FIG. 4B indicates the exergy balance calculated by the following (Equation 3). That is, "Curve 3" is the difference obtained by subtracting the value of "Line 1" and the value of "Curve 1" from the value of "Curve 2" at an arbitrary pressure value of vaporized ammonia (the value on the X-axis). In addition, it is shown that the more positive and the larger the value of this exergy balance (Curve 3) is, the more the total power generation amount of the first power generation facility 2 and the second power generation facility 3 increases compared to the power generation amount of a conventional thermal power generation facility (corresponding to only the first power generation facility 2).

(Equation 3)
・[Exergy balance (curve 3)] = [Vaporized NH3 exergy (curve 2)] - [Supplied steam exergy (curve 1)] - [Required pump power (line 1)]

As shown in the graph of FIG. 4B, the exergy balance (curve 3) begins to increase less when the vaporized ammonia pressure (X-axis) exceeds 6 MPaG, and peaks at 16 MPaG.
In addition, the volume of liquid ammonia changes less when pressurized than that of vaporized ammonia gas. Therefore, even if additional power energy (line 1) is required to drive the pressurizing equipment _P4 in the second power generation facility 3 shown in FIG. 1 or 2, the increase in power energy has a small effect on the exergy balance (curve 3) described above (see FIG. 4B).
Therefore, in the combined power generation system 1A according to this embodiment or the combined power generation system 1B according to the modified example, ammonia, which is a polar molecule, is used as the heat medium used in the second power generation facility 3, and the liquid ammonia supplied to the ammonia vaporization equipment 16 is pressurized to 6 MPaG or more, so that the total power generation amount of the first power generation facility 2 and the second power generation facility 3 can be made larger than the power generation amount of a conventional thermal power generation facility (corresponding to only the first power generation facility 2).
When the ammonia turbine 20 is operated using vaporized ammonia to generate electricity (second power generation facility 3), the upper limit of the liquid ammonia pressure is desirably set to less than 11.2 MPaG, which is the critical pressure of ammonia.

<3-4: Regarding the first power generation facility and the second power generation facility>
Here, with reference to Figures 1 and 2 above, an example of a more specific aspect of the first power generation facility 2 and the second power generation facility 3 in the combined power generation system 1A according to this embodiment or the combined power generation system 1B according to the modified example will be described.
As shown in Figures 1 and 2, the steam turbine 8 in the first power generation facility 2 may include, for example, a high-pressure steam turbine 8a that discharges high-pressure exhaust steam, an intermediate-pressure steam turbine 8b that discharges intermediate-pressure exhaust steam having an outlet temperature of 200 to 450°C, and a low-pressure steam turbine 8c that discharges low-pressure exhaust steam having an outlet temperature of 30 to 200°C.
Furthermore, as shown in FIGS. 1 and 2 , the ammonia vaporization equipment 16 in the second power generation facility 3 may include a preheater 17 (heat exchanger) that preheats the liquid ammonia supplied from the storage equipment 15, a vaporizer 18 (heat exchanger) that vaporizes the liquid ammonia preheated in the preheater 17, and a superheater 19 (heat exchanger) that superheats the ammonia gas vaporized in the vaporizer 18.

When the first power generation facility 2 and the second power generation facility 3 shown in Figure 1 or Figure 2 are configured as described above, they may be provided with a medium-pressure exhaust steam supply line L1 (the part indicated by a dashed line in piping _{Lw in Figures 1 and 2)} that supplies a portion of the medium-pressure exhaust steam discharged from the medium-pressure steam turbine _8b of the first power generation facility 2 to the superheater 19 and supplies a portion of the medium-pressure exhaust steam cooled in the superheater 19 to the vaporizer 18 (optional component).
When the combined power generation system 1A according to this embodiment or the combined power generation system 1B according to the modified example includes the medium pressure exhaust steam supply line _L1 as described above, the liquid ammonia can be efficiently vaporized by utilizing the exhaust steam (medium pressure exhaust steam) supplied from the first power generation facility 2.
More specifically, when comparing the latent heat of vaporization of superheated ammonia (ammonia gas) and that of low-pressure exhaust steam, the latent heat of vaporization of the low-pressure exhaust steam is significantly larger.
Latent heat of vaporization of ammonia gas at 120 ° C: 480 (kJ / kg)
Latent heat of vaporization of water vapor at 144 ° C: 2130 (kJ / kg)
Therefore, by using the medium-pressure exhaust steam discharged from the medium-pressure steam turbine 8b of the first power generation facility 2 as the heat source used in the superheater 19 and vaporizer 18 of the ammonia vaporization equipment 16, ammonia can be efficiently vaporized and superheated using a small amount of medium-pressure exhaust steam.
As a result, the output of the ammonia turbine 20 by the superheated ammonia gas can be increased.

Furthermore, when the first power generation facility 2 and the second power generation facility 3 shown in FIG. 1 or FIG. 2 are configured as described above, a hot water supply line L 2 (a portion indicated by a dashed dotted line in the piping L _w in FIG. 1 and FIG. 2 ) may be provided to supply hot water (second hot water) generated from equipment related to the low-pressure steam turbine 8 c of the first power generation facility 2 to the preheater 17 of the ammonia vaporization facility ₁₆ in the second power generation facility 3 (optional component).
The second hot water in the hot water supply line _L2 may be hot water after heat exchange generated in a condenser 11 (heat exchanger) and/or a heat exchanger 12 provided downstream of the low-pressure steam turbine 8c of the first power generation facility 2 shown in Fig. 1 or 2. More specifically, the second hot water may be, for example, feed water on the low-pressure steam turbine 8c side of the first power generation facility 2, a feed water heater drain, or the like.
Furthermore, separately from or in addition to the second hot water, a line may be provided to supply hot water (first hot water) generated from the vaporizer 18 of the ammonia vaporization equipment 16 in the second power generation facility 3 or its related equipment to the preheater 17, and this line may be used as the hot water supply line _L2 (not shown).
The first hot water may be, for example, evaporator drain.
In the case where the combined power generation system 1A according to this embodiment or the combined power generation system 1B according to the modified example includes a hot water supply line _L2 in addition to the intermediate pressure exhaust steam supply line _L1 , the exhaust heat discharged into the environment in the first power generation facility 2 can be effectively utilized for vaporizing (more specifically, preheating) the liquid ammonia.

In the combined power generation system 1A of this embodiment or the combined power generation system 1B of the modified example, in order to make it easier to understand the technical contents of the invention, an example is given in which the first power generation facility 2 has one each of a high-pressure steam turbine 8a, an intermediate-pressure steam turbine 8b, and a low-pressure steam turbine 8c, but the first power generation facility 2 may have multiple each of the high-pressure steam turbine 8a, the intermediate-pressure steam turbine 8b, and the low-pressure steam turbine 8c (optional components).
Furthermore, in the combined power generation system 1A according to this embodiment or the combined power generation system 1B according to the modified example, the first power generation facility 2 may include a plurality of ammonia turbines 20 as necessary (optional components).
In either case, the same actions and effects as those of the combined power generation system 1A according to this embodiment or the combined power generation system 1B according to the modified example are achieved.

In the above-described embodiment and its modified examples, the turbine driving fluid that drives the ammonia turbine 20 is ammonia gas (superheated ammonia gas) as an example. However, this turbine driving fluid may be a supercritical ammonia fluid (optional component).
In this case, instead of the ammonia vaporization equipment 16 shown in FIGS. 1 and 2 , an energy addition equipment (not shown) is provided that heats (residual heat of exhaust steam) and pressurizes (power for a pump or the like) liquid ammonia to generate a supercritical fluid of ammonia.
Furthermore, the supercritical ammonia fluid produced in the energy addition facility is vaporized in an ammonia turbine 20 .
In this case as well, the same actions and effects as those of the combined power generation system 1A according to the above-described embodiment or the combined power generation system 1B according to the modified example are achieved.
When using ammonia supercritical fluid as the turbine driving fluid, the pressure of the ammonia is desirably set to 11.2 to 16 MPaG, which is the critical pressure of ammonia, taking into account the exergy balance (see FIG. 4B).

[4: Simulation to confirm the effect of the present invention]
Simulations performed for the purpose of confirming the effects of the combined power generation system 1A according to this embodiment or the combined power generation system 1B according to the modified example will be described with reference to FIGS.
<4-1: Simulation settings, etc.>
A simplified type thermal power generation facility corresponding to the first power generation facility 2 shown in FIG. 1 was used as a model (see FIG. 5 below, hereinafter also simply referred to as the "simplified model"), and the method of vaporizing liquid ammonia supplied to the combustion section 5 of the boiler facility 4 was set to the following five types (Comparative Examples 1 and 2 and Examples 1 to 3), and the exergy balance was simulated.
This simulation was performed using "AspenPlus V14" manufactured by AspenTech.
The method of calculating the exergy balance in this simulation is the same as that in the above (Equation 3). However, when liquid ammonia is not pressurized in each of the cases shown below, the value of "required power of pump (line 1)" in the above (Equation 3) becomes zero.
Furthermore, the settings and common conditions for the five simulated cases (Comparative Examples 1 and 2 and Examples 1 to 3) are shown in Table 1 below.
FIG. 5 is a diagram showing an outline of a simplified model of a thermal power generation facility (corresponding to the first power generation facility 2 in FIG. 1 ) common to the following five cases (Comparative Examples 1 and 2 and Examples 1 to 3). FIG. 6 is a diagram showing an outline of the simulation model of Comparative Example 1. FIG. 7 is a diagram showing an outline of the simulation model of Comparative Example 2. In addition, FIG. 8 is a diagram showing an outline of the simulation model of Example 1. And FIG. 9 is a diagram showing an outline of the simulation model of Example 2. And FIG. 10 is a diagram showing an outline of the simulation model of Example 3.
In each of the simulation models shown in Figs. 8 to 10, the destination of the exhaust ammonia gas discharged from the ammonia gas turbine (corresponding to the ammonia turbine 20 in Figs. 1 and 2) is simply displayed as "to the boiler". This is because the heating section of the boiler is divided into a "coal economizer", a "heater", and a "reheater" for the purpose of the simulation.
In addition, since this simulation is based on the premise that the turbine is driven by completely gasified ammonia, a configuration corresponding to the ammonia turbine 20 shown in FIGS. 1 and 2 is specifically referred to as an "ammonia gas turbine."

<4-2: Simulation results>
4-2-1: Amount of steam required to produce 1 ton of ammonia gas FIG. 11 is a graph showing the amount of steam required to produce 1 ton of ammonia gas in each of the simulation models of Comparative Examples 1 and 2 and Examples 1 to 3.
As shown in FIG. 11, in all cases except for Comparative Example 2 in which the steam from the condenser is used to vaporize the liquid ammonia, the steam (thermal energy) used to operate the steam turbine is used to vaporize the liquid ammonia.
In other words, when part of the steam that operates the steam turbine is diverted for the purpose of vaporizing liquid ammonia (Comparative Example 1, Examples 1 to 3), a reduction in the output of the steam turbine is unavoidable.
On the other hand, in Comparative Example 2 in which the steam from the condenser is used to vaporize the liquid ammonia, the reduction in the steam turbine output is not an issue, but there is a limit to the amount of liquid ammonia that can be vaporized.

4-2-2: Specific exergy of each fluid Fig. 12 is a graph showing the specific exergy of each fluid. Fig. 13 is a graph showing the estimated results of the total power generation amount in each simulation model of Comparative Examples 1 and 2 and Examples 1 to 3.
The estimated values of the specific exergy of each fluid shown in Fig. 12 were used to estimate the total power generation amount for each simulation model shown in Fig. 13. The reference environment settings used to calculate the specific exergy of each fluid shown in Fig. 12 are shown in Table 2 below. The specific exergy of each fluid was estimated using "REFPROP Version 10" from the National Institute of Standards and Technology (NSIT) in the United States.

As shown in FIG. 12, superheated ammonia gas (pressurized superheated vaporized NH ₃ ) has a specific exergy approximately equal to that of steam (300 kPaG steam) for operating an intermediate pressure (steam) turbine.
Therefore, as shown in Figure 13, by operating an ammonia gas turbine ( _NH3 turbine) with superheated ammonia gas (pressurized superheated vaporized _NH3 ) generated using the residual heat of the steam (300 kPaG steam) for operating the medium-pressure (steam) turbine, it is possible to compensate for the output loss of the medium-pressure (steam) turbine in a simplified model of a thermal power plant.

4-2-3: Exergy balance per ton of ammonia gas FIG. 14 is a graph showing the estimation results of the exergy balance per ton of ammonia gas in each of the simulation models of Comparative Examples 1 and 2 and Examples 1 to 3.
As shown in FIG. 14, in Examples 1 to 3 in which the vaporized ammonia gas was further converted into superheated ammonia gas to operate the ammonia gas turbine, the exergy balance was positive.

4-2-4: Summary Therefore, according to the combined power generation system 1A of this embodiment or the combined power generation system 1B of the modified example, a part of the steam that operates the steam turbine 8 (particularly the medium-pressure steam turbine 8b) of the first power generation facility 2 is used to generate superheated ammonia gas, which is the turbine driving fluid, from liquid ammonia, and this superheated ammonia gas is used to operate the ammonia turbine 20. Furthermore, by using the exhaust ammonia gas as fuel for combustion, the reduction in output of the first power generation facility 2 due to the vaporization (and superheating) of ammonia can be compensated for by the power generation of the second power generation facility 3.
Therefore, according to the combined power generation system 1A of this embodiment or the combined power generation system 1B of the modified example, as well as the combined power generation system of the present invention in which the turbine driving fluid in the second power generation facility 3 is ammonia supercritical fluid, a large amount of ammonia gas for fuel can be produced while suppressing energy loss during vaporization.

As explained above, the present invention is a combined power generation system and method that can heat liquid ammonia to produce a large amount of ammonia gas for combustion, and that can suppress a decrease in the power output of a power generation facility even if thermal energy for power generation in the power generation facility is diverted, and can be used in technical fields related to combined facilities such as power generation facilities and chemical plants.

1A Combined power generation system 1B Combined power generation system 2 First power generation facility 3 Second power generation facility 4 Boiler facility 5 Combustion section 6 Fuel supply device 7 Steam generator 7a Steam generator 7b Steam generator 8 Steam turbine 8a High pressure steam turbine 8b Intermediate pressure steam turbine 8c Low pressure steam turbine 9 First generator 10 Water supply facility 11 Condenser (heat exchanger)
12 Heat exchanger 13 Heat exchanger 14 Deaerator 15 Storage equipment 16 Ammonia vaporization equipment (energy addition equipment)
17 Preheater 18 Vaporizer 19 Superheater 20 Ammonia turbine 21 Second generator 22 Optional equipment 23 Combustion section L _w Steam supply pipe L ₁ Intermediate pressure exhaust steam supply line L ₂ Hot water supply line L _a Ammonia supply line P ₁ Pump P ₂ Pump P ₃ Pump P ₄ Pressurization equipment

Claims (8)

a first power generation facility including a boiler facility for generating steam, a steam turbine driven by the steam, and a first generator connected to the steam turbine for generating electric power;
a second power generation facility including a storage facility for storing liquid ammonia, an energy addition facility for converting the liquid ammonia supplied from the storage facility into a turbine driving fluid by using residual heat of exhaust steam from the steam turbine, an ammonia turbine driven by the turbine driving fluid generated in the energy addition facility, and a second generator connected to the ammonia turbine for generating power,
A combined cycle power generation system comprising: a combustion section capable of combusting exhaust ammonia gas discharged from the boiler facility or the ammonia turbine; and at least one facility other than the boiler facility, the exhaust ammonia gas being combusted. The combined power generation system according to claim 1, characterized in that the exhaust ammonia gas is combusted in the boiler equipment. The combined power generation system according to claim 1 or 2, characterized in that it is provided with a pressurizing device that pressurizes the liquid ammonia supplied to the energy addition device to 6 MPaG or more. The steam turbine includes:
an intermediate pressure steam turbine that discharges intermediate pressure exhaust steam having an outlet temperature of 200 to 450°C;
A low-pressure steam turbine is provided which discharges low-pressure exhaust steam having an outlet temperature of 30 to 200°C.
The energy addition facility is an ammonia vaporization facility,
A preheater for preheating the liquid ammonia;
A vaporizer that vaporizes the liquid ammonia preheated in the preheater;
A superheater is provided for superheating the ammonia gas vaporized in the vaporizer,
A medium pressure exhaust steam supply line that supplies a portion of the medium pressure exhaust steam to the superheater and supplies a portion of the medium pressure exhaust steam whose temperature has been reduced in the superheater to the vaporizer;
3. The combined power generation system according to claim 1 or claim 2, further comprising a hot water supply line that supplies first hot water generated from the vaporizer or its associated equipment, and/or second hot water generated from associated equipment of the low-pressure steam turbine to the preheater. The combined power generation system according to claim 1, characterized in that the exhaust ammonia gas discharged from the ammonia turbine is supplied to the boiler equipment or the optional equipment by using the excess pressure of the exhaust ammonia gas. The combined power generation system according to claim 1, characterized in that the liquid ammonia contains 1% by mass or less of water. The combined power generation system according to claim 6, characterized in that the temperature of the exhaust ammonia gas supplied to the combustion section of the boiler equipment or any of the equipment is 18.8°C or higher. A steam turbine connected to a first generator is driven by steam generated in the boiler facility to generate first electric power;
generating a turbine driving fluid from liquid ammonia using residual heat of exhaust steam from the steam turbine, and driving an ammonia turbine connected to a second generator with the turbine driving fluid to generate second electric power;
A combined cycle power generation method, comprising combusting exhaust ammonia gas discharged from the ammonia turbine in the boiler facility or in at least one facility other than the boiler facility.

Images