Power generation system
The power generation system addresses inefficiencies by using waste heat from various sources to heat liquid ammonia, improving combustion efficiency and overall system performance.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- IHI CORP
- Filing Date
- 2025-11-11
- Publication Date
- 2026-05-21
AI Technical Summary
Existing power generation systems using ammonia as fuel face inefficiencies due to the high energy required to raise the temperature of liquid ammonia, leading to a loss of combustion energy and decreased system efficiency.
A power generation system that utilizes waste heat sources within the system to heat liquid ammonia before combustion, incorporating multiple heat exchangers in various fluid paths to transfer heat from exhaust gases, steam, compressed air, lubricating oil, and generator waste heat to the liquid ammonia.
Improves system efficiency by supplying the necessary heat to raise the temperature of liquid ammonia, reducing energy loss and enhancing combustion efficiency.
Smart Images
Figure JP2025039416_21052026_PF_FP_ABST
Abstract
Description
Power generation system
[0001] The present disclosure relates to a power generation system.
[0002] In recent years, power generation systems that obtain power by burning ammonia, which is a renewable energy source, have been under consideration. In particular, a power generation system that generates steam by utilizing the heat of the exhaust gas of a gas turbine and generates electricity with a steam turbine is called a gas turbine combined cycle (GTCC). Ammonia does not contain carbon in its molecule and does not produce carbon dioxide even when burned. Therefore, by including ammonia in the fuel, the amount of carbon dioxide emissions into the atmosphere can be reduced.
[0003] Patent Document 1 discloses a gas turbine system provided with a heat exchanger that transfers the cold thermal energy of liquid ammonia to the air flowing into the gas turbine and supplies the ammonia heated by heat exchange to a combustor.
[0004] Japanese Unexamined Patent Application Publication No. 2024-038770
[0005] When using liquid ammonia as fuel, it is necessary to supply it to the combustor in a pressurized state. Ammonia has a boiling point of -33°C at normal pressure, but its boiling point rises to about 50°C when pressurized. In a gas turbine system such as that of Patent Document 1, the large amount of energy required to raise the temperature of liquid-phase ammonia leads to a loss of combustion energy and causes a decrease in system efficiency. On the other hand, the liquid ammonia before being supplied to the combustor is in a temperature range that is easy to utilize as a cooling source in the normal temperature region, but it has not been utilized within the system. From the above, in a power generation system that obtains power by burning ammonia in a combustor, it has been an issue to effectively utilize the waste heat source within the system to supply the amount of heat required to raise the temperature of liquid ammonia and improve system efficiency.
[0006] Therefore, an object of the present disclosure is to provide a power generation system with improved system efficiency by supplying the amount of heat required to raise the temperature of liquid ammonia from a waste heat source within the system.
[0007] The power generation system according to this disclosure comprises a combustor to which liquid ammonia is supplied via an ammonia passage, and a gas turbine that generates rotational power from exhaust gas discharged from the combustor. The power generation system comprises an economizer to which exhaust gas discharged from the combustor is supplied via an exhaust passage, and a steam turbine connected to the economizer via a first heat transfer medium passage and driven by the supply of a first phase-changing heat transfer medium. The power generation system comprises a condenser connected via a first heat transfer medium passage to which the first heat transfer medium is supplied, and at least one heat exchanger located in the ammonia passage to heat the liquid ammonia before it is supplied to the combustor. The power generation system comprises a generator connected to the gas turbine and having a second heat transfer medium passage for circulating a second heat transfer medium. Compressed air is supplied to the combustor via an intake passage, and a lubricating oil passage for circulating lubricating oil is located in the gas turbine. At least one heat exchanger is located at at least one location selected from the group consisting of the exhaust passage, the first heat transfer medium passage, the intake passage, the second heat transfer medium passage, and the lubricating oil passage, and heats the liquid ammonia.
[0008] The power generation system may include at least one heat exchanger, which may consist of a first heat exchanger and a second heat exchanger. The first heat exchanger may be located in the first heat transfer fluid passage between the steam turbine and the condenser, and may exchange heat between liquid ammonia and the first heat transfer fluid. The second heat exchanger may be located in at least one location selected from the group consisting of an exhaust passage, an intake passage, a second heat transfer fluid passage, and a lubricating oil passage.
[0009] The power generation system may include an ammonia tank in which liquid ammonia is stored, and a boil-off gas compressor connected to the ammonia tank for compressing the boil-off gas produced when liquid ammonia vaporizes in the ammonia tank. At least one heat exchanger may be located in the ammonia flow path that returns the boil-off gas compressed by the boil-off gas compressor back to the ammonia tank, and may exchange heat between the liquid ammonia and the boil-off gas compressed by the boil-off gas compressor.
[0010] At least one heat exchanger may be located downstream of the economizer in the exhaust flow path to exchange heat between liquid ammonia and exhaust gas.
[0011] The power generation system may include a first compressor that compresses air taken in through an intake passage, and a second compressor connected to a combustor via an intake passage that compresses the air compressed by the first compressor and supplies compressed air to the combustor. At least one heat exchanger may be located in the intake passage between the first and second compressors to exchange heat between liquid ammonia and the air compressed by the first compressor.
[0012] At least one heat exchanger may be placed in the second heat transfer fluid channel to exchange heat between liquid ammonia and the waste heat from the generator.
[0013] At least one heat exchanger may be placed in the lubrication oil flow path to exchange heat between liquid ammonia and the waste heat from the gas turbine.
[0014] The first heat transfer fluid passage may be connected to a blowdown water discharge section for discharging blowdown water generated from the steam turbine. At least one heat exchanger may be placed in the first heat transfer fluid passage between the steam turbine and the blowdown water discharge section to exchange heat between liquid ammonia and blowdown water.
[0015] According to this disclosure, a power generation system with improved system efficiency can be provided by supplying the amount of heat required to raise the temperature of liquid ammonia from a waste heat source within the system.
[0016] Figure 1 is a schematic diagram showing a power generation system according to the first embodiment. Figure 2 is a schematic diagram showing a power generation system according to the second embodiment. Figure 3 is a schematic diagram showing a power generation system according to the third embodiment. Figure 4 is a schematic diagram showing a power generation system according to the fourth embodiment. Figure 5 is a schematic diagram showing a power generation system according to the fifth embodiment. Figure 6 is a schematic diagram showing a power generation system according to the sixth embodiment. Figure 7 is a schematic diagram showing a power generation system according to the seventh embodiment.
[0017] Several exemplary embodiments will be described below with reference to the drawings. Note that the dimensional ratios in the drawings are exaggerated for illustrative purposes and may differ from the actual ratios.
[0018] [First Embodiment] Figure 1 is a schematic diagram showing the configuration of the power generation system 1 according to this embodiment. As shown in Figure 1, the power generation system 1 comprises a combustor 12, a gas turbine 11c, an economizer 14, a steam turbine 16, a condenser 17, a heat exchanger 20a, and a generator M.
[0019] The gas turbine 11c is connected to the combustor 12 via the exhaust passage 102. As described later, liquid ammonia is supplied to the combustor 12 via the ammonia passage 103.
[0020] A compressor is connected to the combustor 12 via an intake passage 101, and compressed air is supplied to it. Multiple compressors may be installed, and as shown in Figure 1, a first compressor 11a may be provided as a low-pressure compressor and a second compressor 11b may be provided as a high-pressure compressor. That is, the first compressor 11a and the second compressor 11b may be provided in the intake passage 101 connected to the combustor 12.
[0021] Compressed air supplied to the combustor 12 flows through the intake passage 101. An intake port (not shown) is provided at the upstream end of the intake passage 101 for taking in air from the outside. The system may also include a first compressor 11a that compresses the air taken in through the intake passage 101 from the intake port, and a second compressor 11b that is connected to the combustor 12 via the intake passage 101, compresses the air compressed by the first compressor 11a, and supplies compressed air to the combustor 12.
[0022] The gas turbine 11c is located in the exhaust passage 102 connected to the combustor 12. Exhaust gas discharged from the combustor 12 flows through the exhaust passage 102. The exhaust gas discharged from the combustor 12 passes through the gas turbine 11c and is sent to the downstream side of the exhaust passage 102 from the gas turbine 11c. The gas turbine 11c generates rotational power by being rotated by the exhaust gas.
[0023] The gas turbine 11c is connected to a compressor by a shaft, and the compressor rotates together with the gas turbine 11c. The gas turbine 11c may also be connected to a first compressor 11a and a second compressor 11b by a shaft, and the first compressor 11a and the second compressor 11b may rotate together with the gas turbine 11c.
[0024] The gas turbine 11c is equipped with a lubricating oil passage 106 for circulating lubricating oil for purposes such as lubrication, heat removal, or cooling of components within the gas turbine 11c. Preferably, a pump 24 is connected to the gas turbine 11c via the lubricating oil passage 106. By providing the pump 24, the lubricating oil in the lubricating oil passage 106 can be circulated with sufficient pressure and flow rate.
[0025] A generator M is connected to the gas turbine 11c. The generator M rotates together with the gas turbine 11c and generates electricity.
[0026] The generator M is equipped with a second heat transfer medium passage 107 for circulating a second heat transfer medium to remove and cool the heat generated during operation of the generator M's core. The second heat transfer medium is preferably lubricating oil or water. It is also preferable that a pump 25 is connected to the generator M via the second heat transfer medium passage 107. By providing the pump 25, the second heat transfer medium in the second heat transfer medium passage 107 can be circulated with sufficient pressure and flow rate.
[0027] As described above, compressed air compressed by the compressor is supplied to the combustor 12 from the intake passage 101, and ammonia is supplied as fuel in a liquid state. However, ammonia may be supplied to the combustor 12 in a partially gaseous state. Combustion is carried out in the combustor 12 using ammonia as fuel. The exhaust gas produced in the combustor 12 is discharged into the exhaust passage 102.
[0028] The power generation system 1 may include an ammonia tank 13 in which liquid ammonia is stored. In the ammonia tank 13, for example, ammonia is maintained in a liquid state 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 may store ammonia in the presence of trace amounts of water and ammonia, respectively. Alternatively, the ammonia may exist in the form of aqueous ammonia. Note that the ammonia supply source does not necessarily have to be a component of the ammonia tank 13. In other words, the ammonia tank 13 may take in ammonia from an externally installed ammonia supply source.
[0029] The power generation system 1 may include a boil-off gas compressor 40 connected to an ammonia tank 13 in which liquid ammonia is stored. The boil-off gas compressor 40 is provided to compress and re-liquefy the boil-off gas generated when liquid ammonia vaporizes in the ammonia tank 13. In addition to the ammonia flow path 103 that supplies liquid ammonia from the ammonia tank 13 to the combustor 12, there is an ammonia flow path 103 that discharges the boil-off gas from the ammonia tank 13 to the boil-off gas compressor 40. Furthermore, there is an ammonia flow path 103 that returns the boil-off gas compressed by the boil-off gas compressor 40 (hereinafter referred to as post-compressed boil-off gas) back to the ammonia tank 13.
[0030] The ammonia tank 13 is connected to the combustor 12 via the ammonia flow path 103. Liquid ammonia flows through the ammonia flow path 103. Liquid ammonia is then supplied from the ammonia tank 13 to the combustor 12 via the ammonia flow path 103.
[0031] In the ammonia flow path 103, it is preferable to place a pump 21 between the ammonia tank 13 and the combustor 12. By placing the pump 21, the liquid ammonia supplied from the ammonia tank 13 can be pressurized. As described later, the power generation system 1 is equipped with at least one heat exchanger 20a that heats the liquid ammonia before it is supplied to the combustor 12. Specifically, as shown in Figure 1, the heat exchanger 20a is located upstream of the combustor 12 in the ammonia flow path 103. Therefore, it is preferable to increase the capacity of the pump 21 to supply liquid ammonia to the combustor 12, taking into account the pressure loss due to the installation of the heat exchanger 20a. Similarly, in other embodiments where heat exchangers 20b, 20c, 20d, 20e, 20f, and 20g are installed, it is preferable to increase the capacity of the pump 21 to supply liquid ammonia to the combustor 12, taking into account the pressure loss of the liquid ammonia.
[0032] An economizer 14 is provided downstream of the gas turbine 11c in the exhaust passage 102. Exhaust gas discharged from the combustor 12 is supplied to the economizer 14 via the exhaust passage 102.
[0033] The economizer 14 is supplied with exhaust gas discharged from the combustor 12 through the exhaust passage 102, and a first heat transfer medium is supplied through the first heat transfer medium passage 104. The first heat transfer medium is a phase-changing heat transfer medium, preferably water. When the first heat transfer medium is water, the water flowing through the first heat transfer medium passage 104 is heated in the economizer 14 by the exhaust gas flowing through the exhaust passage 102, vaporizes into a gas, i.e., water vapor. The water vapor generated in the economizer 14 is used for power generation, as will be described later. The exhaust passage 102 may be connected to an exhaust tower 15 downstream of the economizer 14. The exhaust gas discharged from the combustor 12 may pass through the gas turbine 11c and the economizer 14, be sent to the exhaust tower 15, and discharged from the exhaust tower 15.
[0034] The economizer 14 is connected to the steam turbine 16. Specifically, the outlet of the economizer 14 is connected to the inlet of the steam turbine 16 via the first heat transfer medium passage 104. The first heat transfer medium is then supplied to the steam turbine 16 via the first heat transfer medium passage 104. When the first heat transfer medium is water, the steam generated in the economizer 14 is sent to the steam turbine 16 via the first heat transfer medium passage 104. The steam then rotates the steam turbine 16, generating rotational power. In other words, the steam turbine 16 is driven by the supply of a first heat transfer medium that undergoes a phase change. The rotational power generated by the steam turbine 16 is used for power generation.
[0035] The steam turbine 16 may be connected to a blowdown water discharge section 50 via a first heat transfer medium passage 104. In order to periodically replace the steam in the first heat transfer medium passage 104, blowdown water generated from the steam turbine 16 may be discharged from the blowdown water discharge section 50. That is, the first heat transfer medium passage 104 may be connected to a blowdown water discharge section 50 that discharges blowdown water generated from the steam turbine 16.
[0036] The steam turbine 16 is connected to the condenser 17. Specifically, the outlet of the steam turbine 16 is connected to the inlet of the condenser 17 via the first heat transfer medium passage 104. In other words, the steam turbine 16 and the condenser 17 are connected to the economizer 14 via the first heat transfer medium passage 104.
[0037] The condenser 17 is supplied with a first heat transfer medium from the first heat transfer medium channel 104, and a third heat transfer medium from the third heat transfer medium channel 105. The third heat transfer medium may be, for example, seawater, river water, groundwater, or air.
[0038] As described above, seawater taken in from the sea may flow through the third heat transfer medium channel 105. When the third heat transfer medium is seawater, the seawater taken in from the seawater intake section 30 and passing through the third heat transfer medium channel 105 is discharged back into the sea from the seawater discharge section 31. A pump 19 is provided upstream of the condenser 17 in the third heat transfer medium channel 105, and the pump 19 pressurizes the seawater taken into the third heat transfer medium channel 105 and sends it downstream.
[0039] In the condenser 17, heat exchange takes place between the first heat transfer medium flowing through the first heat transfer medium channel 104 and the third heat transfer medium flowing through the third heat transfer medium channel 105. When the first heat transfer medium is water and the third heat transfer medium is seawater, the temperature of the water vapor flowing through the first heat transfer medium channel 104 is higher than the temperature of the seawater flowing through the third heat transfer medium channel 105. Therefore, in the condenser 17, the water vapor flowing through the first heat transfer medium channel 104 is cooled by the seawater flowing through the third heat transfer medium channel 105, and liquefied into water.
[0040] It is preferable that a pump 18 is provided downstream of the condenser 17 in the first heat transfer medium flow path 104. When the first heat transfer medium is water, the pump 18 pressurizes the water generated in the condenser 17 and sends it downstream. The water sent by the pump 18 is sent to the economizer 14 via the first heat transfer medium flow path 104.
[0041] The power generation system 1 according to this embodiment includes at least one heat exchanger 20a that heats liquid ammonia before it is supplied to the combustor 12. As shown in Figure 1, the heat exchanger 20a is located upstream of the combustor 12 in the ammonia flow path 103. The ammonia flow path 103 passes through the heat exchanger 20a. As described above, a pump 21 is provided between the heat exchanger 20a and the ammonia tank 13 in the ammonia flow path 103. The pump 21 pressurizes the liquid ammonia supplied from the ammonia tank 13 and sends it downstream. The liquid ammonia sent by the pump 21 is sent to the heat exchanger 20a.
[0042] On the other hand, at least one heat exchanger 20a is disposed in an ammonia flow path 103 that returns the post-compression boil-off gas to the ammonia tank 13. In the heat exchanger 20a, heat exchange is performed between the post-compression boil-off gas and liquid ammonia. The temperature of the post-compression boil-off gas is higher than the temperature of the liquid ammonia. Therefore, in the heat exchanger 20a, the post-compression boil-off gas is cooled by the liquid ammonia. On the other hand, in the heat exchanger 20a, the liquid ammonia is heated to such an extent that it does not vaporize by the post-compression boil-off gas. Thus, the heat of the post-compression boil-off gas can be utilized to heat the liquid ammonia. The heated liquid ammonia is supplied to the combustor 12 in a liquid state.
[0043] As described above, when installing the heat exchanger 20a, it is preferable to increase the capacity of the pump 21 disposed in the ammonia flow path 103 in consideration of the pressure loss of the liquid ammonia. Also, as described above, the liquid ammonia in the ammonia tank 13 is stored at around -30°C. Therefore, in consideration of the possibility that moisture under atmospheric pressure freezes on the heat transfer surface when the liquid ammonia is supplied to the heat exchanger 20a, it is preferable to design the heat transfer surface in accordance with the post-compression boil-off gas flowing through the heat exchanger 20a.
[0044] The ammonia flow path 103 may be provided with ammonia treatment equipment 42 for treating the ammonia in the ammonia tank 13. As the ammonia treatment equipment 42, for example, a flare stack equipment or a vent stack equipment may be provided. By providing the flare stack equipment, the ammonia can be burned. Also, by providing the vent stack equipment, the ammonia can be discharged to the atmosphere. Further, the ammonia flow path 103 may be provided with a moisture removal tank 41 for removing moisture in the ammonia.
[0045] Flow control valves 22 and 23 may be provided in the ammonia flow path 103. The flow control valves 22 and 23 can adjust the flow rate of ammonia flowing through the ammonia flow path 103, in particular the flow rate of liquid ammonia sent to the combustor 12. Specifically, the amount of ammonia supplied to the combustor 12 is adjusted by adjusting the opening degree of the flow control valves 22 and 23. The location of the flow control valves 22 and 23 is not particularly limited as long as it is in the ammonia flow path 103. As shown in Figure 1, the flow control valve 22 may be provided downstream of the water removal tank 41 and the ammonia treatment equipment 42, and the flow control valve 23 may be provided in the return line of the ammonia flow path 103.
[0046] As described above, in the power generation system 1 according to this embodiment, the heat exchanger 20a is located upstream of the combustor 12 in the ammonia flow path 103. As a result, the liquid ammonia supplied to the combustor 12 can be heated in the heat exchanger 20a using the compressed boil-off gas. Furthermore, a portion of the energy required to burn the ammonia can be supplied by the waste heat of the compressed boil-off gas. Therefore, the efficiency of the power generation system can be improved.
[0047] In particular, in power generation system 1, the ammonia is heated in the heat exchanger 20a to the extent that it does not vaporize. In other words, in the heat exchanger 20a, the heat of the compressed boil-off gas is used as the sensible heat of the ammonia. Therefore, the ammonia stored in liquid form in the ammonia tank 13 is supplied to the combustor 12 in liquid form without vaporizing in the ammonia flow path 103. If the ammonia were to vaporize in the ammonia flow path 103, additional equipment and complex control would be required to suppress pressure fluctuations of the gaseous ammonia and prevent re-condensation. It would also be necessary to enlarge the piping for circulating the gaseous ammonia. On the other hand, in power generation system 1, since the ammonia does not vaporize in the ammonia flow path 103, these problems do not occur.
[0048] [Second Embodiment] Next, the power generation system 1 according to the second embodiment will be described with reference to FIG. 2. In the description of the second embodiment, the description of the same parts as those in the first embodiment will be omitted or simplified.
[0049] The power generation system 1 according to the present embodiment includes at least one heat exchanger 20b that heats the liquid ammonia before it is supplied to the combustor 12. As shown in FIG. 2, the heat exchanger 20b is disposed upstream of the combustor 12 in the ammonia flow path 103. The ammonia flow path 103 passes through the heat exchanger 20b. A pump 21 is provided between the heat exchanger 20b and the ammonia tank 13 in the ammonia flow path 103 as described above. The pump 21 pressurizes the liquid ammonia supplied from the ammonia tank 13 and sends it downstream. The liquid ammonia sent by the pump 21 is sent to the heat exchanger 20b. The power generation system 1 according to the present embodiment is different from the power generation system 1 according to the first embodiment in that it includes a heat exchanger 20b instead of the heat exchanger 20a. For other points, since they are the same as those of the power generation system 1 according to the first embodiment unless otherwise specified, the description will be omitted.
[0050] On the other hand, at least one heat exchanger 20b is disposed downstream of the economizer 14 in the exhaust gas flow path 102. At least one heat exchanger 20b may be disposed between the economizer 14 and the exhaust tower 15. In the heat exchanger 20b, heat exchange is performed between the exhaust gas flowing through the exhaust gas flow path 102 and the liquid ammonia flowing through the ammonia flow path 103. The maximum temperature of the exhaust gas is generally about 115°C, and the temperature of the exhaust gas is higher than the temperature of the liquid ammonia. Therefore, in the heat exchanger 20b, the exhaust gas is cooled by the liquid ammonia. On the other hand, in the heat exchanger 20b, the liquid ammonia is heated to such an extent that it does not vaporize by the exhaust gas. Thus, the exhaust heat of the exhaust gas can be used to heat the liquid ammonia. The heated liquid ammonia is supplied to the combustor 12 in a liquid state.
[0051] As described above, when installing the heat exchanger 20b, it is preferable to increase the capacity of the pump 21 located in the ammonia flow path 103, taking into account the pressure loss of liquid ammonia. Furthermore, it is preferable to design the heat transfer surface of the heat exchanger 20b to match the exhaust gas flowing through the heat exchanger 20b, taking into account the possibility of freezing on the heat transfer surface.
[0052] The heat exchanger 20b utilizes the waste heat of the exhaust gas flowing through the exhaust passage 102. Since the exhaust gas contains nitrogen oxides, excessive cooling can cause condensation, generating a condensate containing nitric acid, which can corrode the heat transfer tubes in the heat exchanger 20b and potentially lead to leakage of liquid ammonia. Therefore, as a modification of the heat exchanger 20b, an intermediate cycle (not shown) configured to circulate water may be provided. Specifically, the intermediate cycle may include a heat exchanger where heat exchange takes place between the exhaust gas flowing through the exhaust passage 102 and water, a heat exchanger where heat exchange takes place between liquid ammonia flowing through the ammonia passage 103 and water, and a pump. First, the water flowing through the intermediate cycle is heated by the exhaust gas, and then the liquid ammonia is heated by the water flowing through the intermediate cycle. By providing this intermediate cycle, indirect heat exchange can be performed between the exhaust gas and liquid ammonia, and leakage of liquid ammonia can be prevented. Furthermore, the temperature of the exhaust gas and liquid ammonia can be easily adjusted, thereby improving the controllability of the power generation system.
[0053] As described above, in the power generation system 1 according to this embodiment, the heat exchanger 20b is located upstream of the combustor 12 in the ammonia flow path 103. As a result, the liquid ammonia supplied to the combustor 12 can be heated in the heat exchanger 20b using the exhaust gas flowing through the exhaust flow path 102. Then, a portion of the energy required to burn the ammonia can be supplied by the waste heat of the exhaust gas. Therefore, the efficiency of the power generation system can be improved.
[0054] [Third Embodiment] Next, the power generation system 1 according to the third embodiment will be described with reference to Figure 3. In the description of the third embodiment, the same parts as in the first embodiment will be omitted or simplified.
[0055] The power generation system 1 according to this embodiment includes at least one heat exchanger 20c that heats liquid ammonia before it is supplied to the combustor 12. As shown in Figure 3, the heat exchanger 20c is located upstream of the combustor 12 in the ammonia flow path 103. The ammonia flow path 103 passes through the heat exchanger 20c. As described above, a pump 21 is provided between the heat exchanger 20c and the ammonia tank 13 in the ammonia flow path 103. The pump 21 pressurizes the liquid ammonia supplied from the ammonia tank 13 and sends it downstream. The liquid ammonia sent by the pump 21 is sent to the heat exchanger 20c. The power generation system 1 according to this embodiment differs from the power generation system 1 according to the first embodiment in that it includes a heat exchanger 20c instead of a heat exchanger 20a. Other points are the same as the power generation system 1 according to the first embodiment unless otherwise specified, so their explanation is omitted.
[0056] On the other hand, at least one heat exchanger 20c is located between the steam turbine 16 and the condenser 17 in the first heat transfer medium flow path 104. When the first heat transfer medium is water, heat exchange takes place in the heat exchanger 20c between the steam sent from the steam turbine 16 to the condenser 17 and the liquid ammonia flowing through the ammonia flow path 103. The steam sent from the steam turbine 16 to the condenser 17 generally has a condensation temperature of about 40°C, and the temperature of the steam is higher than the temperature of the liquid ammonia. Therefore, in the heat exchanger 20c, the steam is cooled by the liquid ammonia. Consequently, the amount of heat that needs to be recovered from the steam by the third heat transfer medium in the condenser 17 can be reduced, and the amount of the third heat transfer medium taken in can be reduced. Therefore, the power of the pump 19 can be reduced, and the efficiency of the power generation system can be improved.
[0057] Furthermore, in the heat exchanger 20c, the liquid ammonia is heated to a degree that it does not vaporize by the steam sent from the steam turbine 16 to the condenser 17. In this way, the waste heat from the steam sent from the steam turbine 16 to the condenser 17 can be used to heat the liquid ammonia. The heated liquid ammonia is then supplied to the combustor 12 in liquid form.
[0058] As described above, when installing the heat exchanger 20c, it is preferable to increase the capacity of the pump 21 located in the ammonia flow path 103, taking into account the pressure loss of liquid ammonia. Furthermore, it is preferable to design the heat transfer surface of the heat exchanger 20c to match the water vapor circulating inside the heat exchanger 20c, taking into account the possibility of freezing on the heat transfer surface.
[0059] In Figure 3, the heat exchanger 20c is located in the first heat transfer medium flow path 104 between the steam turbine 16 and the condenser 17, that is, upstream of the condenser 17. In a modified power generation system 1 of this embodiment, the heat exchanger 20c may be located in the first heat transfer medium flow path 104 downstream of the condenser 17. When the first heat transfer medium is water, heat exchange takes place in the heat exchanger 20c between the water generated in the condenser 17 and liquid ammonia. The temperature of the water generated in the condenser 17 is higher than the temperature of the liquid ammonia flowing through the ammonia flow path 103. Therefore, in the heat exchanger 20c, the water is cooled by the liquid ammonia and heated by the water to the extent that it does not vaporize. In this way, the waste heat from the water generated in the condenser 17 can be used to heat the liquid ammonia. The heated liquid ammonia is supplied to the combustor 12 in liquid form.
[0060] Furthermore, in a modified power generation system 1 of this embodiment, the heat exchanger 20c may be located in the third heat transfer medium flow path 105. Specifically, it may be located upstream of the condenser 17 in the third heat transfer medium flow path 105, or downstream of the condenser 17. In the heat exchanger 20c, heat exchange takes place between the third heat transfer medium flowing through the third heat transfer medium flow path 105 and the liquid ammonia flowing through the ammonia flow path 103. When the third heat transfer medium is seawater, heat exchange takes place between the seawater and the liquid ammonia in the heat exchanger 20c. The temperature of the seawater is higher than the temperature of the liquid ammonia. Therefore, in the heat exchanger 20c, the seawater is cooled by the liquid ammonia, and the liquid ammonia is heated by the seawater to the extent that it does not vaporize. In this way, the waste heat of the seawater flowing through the third heat transfer medium flow path 105 can be used to heat the liquid ammonia. The heated liquid ammonia is supplied to the combustor 12 in liquid form. Thus, the same effects as the power generation system 1 described above are achieved. Furthermore, since the amount of the third heat transfer medium taken in can be reduced, the power of the pump 19 can be reduced, and the efficiency of the power generation system can be improved.
[0061] As described above, in the power generation system 1 according to this embodiment, the heat exchanger 20c is located upstream of the combustor 12 in the ammonia flow path 103. As a result, the liquid ammonia supplied to the combustor 12 can be heated in the heat exchanger 20c using the first heat medium flowing through the first heat medium flow path 104. Furthermore, a portion of the energy required to burn the ammonia can be supplied by the waste heat of the first heat medium. Therefore, the efficiency of the power generation system can be improved.
[0062] [Fourth Embodiment] Next, the power generation system 1 according to the fourth embodiment will be described with reference to Figure 4. In the description of the fourth embodiment, the same parts as in the first embodiment will be omitted or simplified.
[0063] The power generation system 1 according to this embodiment includes at least one heat exchanger 20d that heats liquid ammonia before it is supplied to the combustor 12. As shown in Figure 4, the heat exchanger 20d is located upstream of the combustor 12 in the ammonia flow path 103. The ammonia flow path 103 passes through the heat exchanger 20d. As described above, a pump 21 is provided between the heat exchanger 20d and the ammonia tank 13 in the ammonia flow path 103. The pump 21 pressurizes the liquid ammonia supplied from the ammonia tank 13 and sends it downstream. The liquid ammonia sent by the pump 21 is sent to the heat exchanger 20d. The power generation system 1 according to this embodiment differs from the power generation system 1 according to the first embodiment in that it includes a heat exchanger 20d instead of a heat exchanger 20a. Other points are the same as the power generation system 1 according to the first embodiment unless otherwise specified, so their explanation is omitted.
[0064] On the other hand, at least one heat exchanger 20d is positioned in the intake air passage 101 between the first compressor 11a, which is a low-pressure compressor, and the second compressor 11b, which is a high-pressure compressor. In the heat exchanger 20d, heat exchange takes place between the air compressed by the first compressor 11a and the liquid ammonia flowing through the ammonia passage 103. The air compressed by the first compressor 11a generally has a maximum temperature of about 200°C, and the temperature of the air compressed by the first compressor 11a is higher than the temperature of the liquid ammonia. Therefore, in the heat exchanger 20d, the air compressed by the first compressor 11a is cooled by the liquid ammonia. On the other hand, in the heat exchanger 20d, the liquid ammonia is heated by the air compressed by the first compressor 11a to the extent that it does not vaporize. In this way, the waste heat from the air compressed by the first compressor 11a can be used to heat the liquid ammonia. The heated liquid ammonia is supplied to the combustor 12 in liquid form.
[0065] As described above, when installing the heat exchanger 20d, it is preferable to increase the capacity of the pump 21 located in the ammonia flow path 103, taking into account the pressure loss of liquid ammonia. Furthermore, it is preferable to design the heat transfer surface of the heat exchanger 20d to match the compressed air flowing through the heat exchanger 20d, taking into account the possibility of freezing on the heat transfer surface.
[0066] As described above, in the power generation system 1 according to this embodiment, the heat exchanger 20d is located upstream of the combustor 12 in the ammonia flow path 103. As a result, the liquid ammonia supplied to the combustor 12 can be heated in the heat exchanger 20d using air compressed by the first compressor 11a. Therefore, a portion of the energy required to burn the ammonia can be supplied by the waste heat of the air compressed by the first compressor 11a. This improves the efficiency of the power generation system.
[0067] [Fifth Embodiment] Next, a power generation system 1 according to the fifth embodiment will be described with reference to Figure 5. In the description of the fifth embodiment, parts that are the same as those in the first embodiment will be omitted or simplified.
[0068] The power generation system 1 according to this embodiment includes at least one heat exchanger 20e that heats liquid ammonia before it is supplied to the combustor 12. As shown in Figure 5, the heat exchanger 20e is located upstream of the combustor 12 in the ammonia flow path 103. The ammonia flow path 103 passes through the heat exchanger 20e. As described above, a pump 21 is provided between the heat exchanger 20e and the ammonia tank 13 in the ammonia flow path 103. The pump 21 pressurizes the liquid ammonia supplied from the ammonia tank 13 and sends it downstream. The liquid ammonia sent by the pump 21 is sent to the heat exchanger 20e. Note that the power generation system 1 according to this embodiment differs from the power generation system 1 according to the first embodiment in that it includes a heat exchanger 20e instead of a heat exchanger 20a. Other points are the same as the power generation system 1 according to the first embodiment unless otherwise specified, so their explanation is omitted.
[0069] On the other hand, at least one heat exchanger 20e is located in the second heat transfer medium flow path 107. In the heat exchanger 20e, heat exchange takes place between the second heat transfer medium circulating in the second heat transfer medium flow path 107 and the liquid ammonia flowing in the ammonia flow path 103. That is, heat exchange occurs in the heat exchanger 20e between the waste heat of the generator M and the liquid ammonia. Since the waste heat of the generator M generally has a maximum temperature of about 150°C, the temperature of the second heat transfer medium circulating in the second heat transfer medium flow path 107 in the generator M is higher than the temperature of the liquid ammonia. Therefore, in the heat exchanger 20e, the second heat transfer medium is cooled by the liquid ammonia. On the other hand, in the heat exchanger 20e, the liquid ammonia is heated by the second heat transfer medium to the extent that it does not vaporize. In this way, the waste heat of the generator M can be used to heat the liquid ammonia. The heated liquid ammonia is supplied to the combustor 12 in liquid form.
[0070] As described above, when installing the heat exchanger 20e, it is preferable to increase the capacity of the pump 21 located in the ammonia flow path 103, taking into account the pressure loss of liquid ammonia. On the other hand, it is also preferable to consider the pressure loss of the second heat medium circulating in the second heat medium flow path 107. For this reason, it is preferable to increase the capacity of the pump 25 located in the second heat medium flow path 107, or to install an auxiliary pump in the second heat medium flow path 107. Furthermore, taking into account the possibility of freezing on the heat transfer surface of the heat exchanger 20e, it is preferable to design the heat transfer surface to match the second heat medium circulating inside the heat exchanger 20e.
[0071] As described above, in the power generation system 1 according to this embodiment, the heat exchanger 20e is located upstream of the combustor 12 in the ammonia flow path 103. As a result, the liquid ammonia supplied to the combustor 12 can be heated in the heat exchanger 20e using the second heat medium circulating in the second heat medium flow path 107. Therefore, a portion of the energy required to burn the ammonia can be supplied by the waste heat of the generator M. This improves the efficiency of the power generation system.
[0072] [Sixth Embodiment] Next, the power generation system 1 according to the sixth embodiment will be described with reference to Figure 6. In the description of the sixth embodiment, the same parts as in the first embodiment will be omitted or simplified.
[0073] The power generation system 1 according to this embodiment includes at least one heat exchanger 20f that heats liquid ammonia before it is supplied to the combustor 12. As shown in Figure 6, the heat exchanger 20f is located upstream of the combustor 12 in the ammonia flow path 103. The ammonia flow path 103 passes through the heat exchanger 20f. As described above, a pump 21 is provided between the heat exchanger 20f and the ammonia tank 13 in the ammonia flow path 103. The pump 21 pressurizes the liquid ammonia supplied from the ammonia tank 13 and sends it downstream. The liquid ammonia sent by the pump 21 is sent to the heat exchanger 20f. The power generation system 1 according to this embodiment differs from the power generation system 1 according to the first embodiment in that it includes a heat exchanger 20f instead of a heat exchanger 20a. Other points are the same as the power generation system 1 according to the first embodiment unless otherwise specified, so their explanation is omitted.
[0074] On the other hand, at least one heat exchanger 20f is located in the lubricating oil passage 106. In the heat exchanger 20f, heat exchange takes place between the lubricating oil circulating in the lubricating oil passage 106 and the liquid ammonia flowing through the ammonia passage 103. That is, heat exchange occurs in the heat exchanger 20f between the waste heat of the gas turbine 11c and the liquid ammonia. Since the waste heat of the gas turbine 11c generally has a maximum temperature of about 180°C, the temperature of the lubricating oil circulating in the lubricating oil passage 106 in the gas turbine 11c is higher than the temperature of the liquid ammonia. Therefore, in the heat exchanger 20f, the lubricating oil is cooled by the liquid ammonia. On the other hand, in the heat exchanger 20f, the liquid ammonia is heated by the lubricating oil to the extent that it does not vaporize. In this way, the waste heat of the gas turbine 11c can be used to heat the liquid ammonia. The heated liquid ammonia is supplied to the combustor 12 in liquid form.
[0075] As described above, when installing the heat exchanger 20f, it is preferable to increase the capacity of the pump 21 located in the ammonia flow path 103, taking into account the pressure loss of liquid ammonia. On the other hand, it is also preferable to consider the pressure loss of the lubricating oil circulating in the lubricating oil flow path 106. For this reason, it is preferable to increase the capacity of the pump 24 located in the lubricating oil flow path 106, or to install an auxiliary pump in the lubricating oil flow path 106. Furthermore, considering the possibility of freezing on the heat transfer surface of the heat exchanger 20f, it is preferable to design the heat transfer surface to match the lubricating oil circulating inside the heat exchanger 20f.
[0076] As described above, in the power generation system 1 according to this embodiment, the heat exchanger 20f is located upstream of the combustor 12 in the ammonia flow path 103. As a result, the liquid ammonia supplied to the combustor 12 can be heated in the heat exchanger 20f using the heat of the lubricating oil circulating in the lubricating oil flow path 106. Therefore, a portion of the energy required to burn the ammonia can be supplied by the waste heat of the gas turbine 11c. This improves the efficiency of the power generation system.
[0077] [Seventh Embodiment] Next, the power generation system 1 according to the seventh embodiment will be described with reference to Figure 7. In the description of the seventh embodiment, the same parts as in the first embodiment will be omitted or simplified.
[0078] The power generation system 1 according to this embodiment includes at least one heat exchanger 20g for heating liquid ammonia before it is supplied to the combustor 12. As shown in Figure 7, the heat exchanger 20g is located upstream of the combustor 12 in the ammonia flow path 103. The ammonia flow path 103 passes through the heat exchanger 20g. As described above, a pump 21 is provided between the heat exchanger 20g and the ammonia tank 13 in the ammonia flow path 103. The pump 21 pressurizes the liquid ammonia supplied from the ammonia tank 13 and sends it downstream. The liquid ammonia sent by the pump 21 is sent to the heat exchanger 20g. The power generation system 1 according to this embodiment differs from the power generation system 1 according to the first embodiment in that it includes a heat exchanger 20g instead of a heat exchanger 20a. Other points are the same as the power generation system 1 according to the first embodiment unless otherwise specified, so their explanation is omitted.
[0079] Meanwhile, at least one heat exchanger 20g is positioned between the steam turbine 16 and the blowdown water discharge section 50 in the first heat transfer medium flow path 104. In the heat exchanger 20g, heat exchange takes place between the blowdown water discharged from the steam turbine 16 to the blowdown water discharge section 50 and the liquid ammonia flowing through the ammonia flow path 103. The blowdown water generally has a maximum temperature of about 100°C, and the temperature of the blowdown water is higher than the temperature of the liquid ammonia. Therefore, in the heat exchanger 20g, the blowdown water is cooled by the liquid ammonia. On the other hand, in the heat exchanger 20g, the liquid ammonia is heated by the blowdown water to a degree that it does not vaporize. In this way, the waste heat of the blowdown water can be used to heat the liquid ammonia. The heated liquid ammonia is supplied to the combustor 12 in liquid form.
[0080] As described above, when installing the heat exchanger 20g, it is preferable to increase the capacity of the pump 21 located in the ammonia flow path 103, taking into account the pressure loss of liquid ammonia. On the other hand, it is also preferable to consider the pressure loss of blowdown water. For this reason, it is preferable to increase the capacity of the pump 18 located in the first heat transfer medium flow path 104, or to install an auxiliary pump in the first heat transfer medium flow path 104 from which the blowdown water is discharged. Furthermore, as described above, it is preferable to design the heat transfer surface of the heat exchanger 20g to match the blowdown water flowing through the heat exchanger 20g, taking into account the possibility of freezing on the heat transfer surface.
[0081] As described above, in the power generation system 1 according to this embodiment, the heat exchanger 20g is located upstream of the combustor 12 in the ammonia flow path 103. As a result, the liquid ammonia supplied to the combustor 12 can be heated in the heat exchanger 20g using blowdown water generated from the steam turbine 16. Therefore, a portion of the energy required to burn the ammonia can be supplied by the waste heat of the blowdown water. This improves the efficiency of the power generation system.
[0082] As described above, the power generation system 1 includes at least one heat exchanger that heats the liquid ammonia before it is supplied to the combustor 12. The at least one heat exchanger is located in the ammonia flow path 103. As shown in Figures 1 to 7, the at least one heat exchanger is located at at least one location selected from the group consisting of the exhaust flow path 102, the first heat transfer medium flow path 104, the intake flow path 101, the second heat transfer medium flow path 107, and the lubricating oil flow path 106, and heats the liquid ammonia. Therefore, by using the power generation system 1, it is possible to effectively utilize the waste heat source within the system, suppress the loss of combustion energy, and achieve energy savings in the amount of heat used to heat the liquid ammonia. On the other hand, it is also possible to effectively utilize the liquid ammonia within the system as a cooling source in the ambient temperature range. In this way, the power generation system 1 can provide a power generation system with improved system efficiency by supplying the amount of heat required to raise the temperature of the liquid ammonia from the waste heat source within the system.
[0083] Furthermore, at least one heat exchanger may comprise a first heat exchanger and a second heat exchanger. The first heat exchanger may be located between the steam turbine 16 and the condenser 17 in the first heat transfer medium passage 104, and may exchange heat between liquid ammonia and the first heat transfer medium. The second heat exchanger may be located at at least one location selected from the group consisting of the exhaust passage 102, the intake passage 101, the second heat transfer medium passage 107, and the lubricating oil passage 106. That is, the first heat exchanger may be installed as heat exchanger 20c, and the second heat exchanger may be installed in any of the positions of heat exchangers 20a, 20b, 20d, 20e, 20f, and 20g. For example, in the power generation system 1, when heat exchangers 20c and 20f are installed, the ammonia passage 103 passing through heat exchanger 20c and the ammonia passage 103 passing through heat exchanger 20f are connected. Then, the liquid ammonia before being supplied to the combustor 12 is heated in the heat exchangers 20c and 20f.
[0084] By having at least one heat exchanger equipped with a first heat exchanger and a second heat exchanger, load adjustment can be flexibly performed in each heat exchanger, making it easier to adjust the temperature of the liquid ammonia and thus improving the controllability of heating the liquid ammonia. For example, in the power generation system 1 equipped with heat exchanger 20c and heat exchanger 20f, even if heat exchanger 20c can only heat the liquid ammonia to about 25°C, heat exchanger 20f can ultimately heat the liquid ammonia to about 50°C.
[0085] Although several embodiments have been described, it is possible to modify or transform the embodiments based on the above disclosure. All components of the above embodiments, and all features described in the claims, may be taken individually and combined, provided that they do not conflict with each other.
[0086] This disclosure can contribute, for example, to United Nations Sustainable Development Goal (SDG) 7, "Ensure access to affordable, reliable, and sustainable energy for all," and Goal 13, "Take urgent action to combat climate change and its impacts."
[0087] The entire contents of Japanese Patent Application No. 2024-199837 (Filing Date: November 15, 2024) are incorporated herein by reference.
[0088] 1 Power Generation System 11a First Compressor 11b Second Compressor 11c Gas Turbine 12 Combustor 13 Ammonia Tank 14 Economizer 16 Steam Turbine 17 Condenser 20a, 20b, 20c, 20d, 20e, 20f, 20g Heat Exchanger 40 Boil-off Gas Compressor 101 Intake Passage 102 Exhaust Passage 103 Ammonia Passage 104 First Heat Transfer Fluid Passage 106 Lubricating Oil Passage 107 Second Heat Transfer Fluid Passage M Generator
Claims
1. A power generation system comprising: a combustor to which liquid ammonia is supplied via an ammonia passage; a gas turbine that generates rotational power using exhaust gas discharged from the combustor; an economizer to which the exhaust gas discharged from the combustor is supplied via an exhaust passage; a steam turbine connected to the economizer via a first heat transfer medium passage and driven by the supply of a first phase-changing heat transfer medium; a condenser connected via the first heat transfer medium passage and supplied with the first heat transfer medium; at least one heat exchanger located in the ammonia passage and heating the liquid ammonia before it is supplied to the combustor; and a generator connected to the gas turbine and having a second heat transfer medium passage for circulating a second heat transfer medium, wherein compressed air is supplied to the combustor via an intake passage; a lubricating oil passage for circulating lubricating oil is located in the gas turbine; and the at least one heat exchanger is located in at least one location selected from the group consisting of the exhaust passage, the first heat transfer medium passage, the intake passage, the second heat transfer medium passage and the lubricating oil passage, and heats the liquid ammonia.
2. The power generation system according to claim 1, wherein the at least one heat exchanger comprises a first heat exchanger and a second heat exchanger, the first heat exchanger is located in the first heat transfer medium passage between the steam turbine and the condenser and exchanges heat between the liquid ammonia and the first heat transfer medium, and the second heat exchanger is located in at least one location selected from the group consisting of the exhaust passage, the intake passage, the second heat transfer medium passage and the lubricating oil passage.
3. The power generation system according to claim 1 or 2, comprising: an ammonia tank in which the liquid ammonia is stored; and a boil-off gas compressor connected to the ammonia tank for compressing the boil-off gas produced when the liquid ammonia vaporizes in the ammonia tank, wherein at least one heat exchanger is located in the ammonia flow path that returns the boil-off gas compressed by the boil-off gas compressor to the ammonia tank, and causes heat exchange between the liquid ammonia and the boil-off gas compressed by the boil-off gas compressor.
4. The power generation system according to any one of claims 1 to 3, wherein the at least one heat exchanger is located downstream of the economizer in the exhaust flow path and exchanges heat between the liquid ammonia and the exhaust gas.
5. A power generation system according to any one of claims 1 to 4, comprising: a first compressor for compressing air taken in through the intake passage; and a second compressor connected to the combustor via the intake passage for compressing the air compressed by the first compressor and supplying the compressed air to the combustor, wherein at least one heat exchanger is located in the intake passage between the first compressor and the second compressor and exchanges heat between the liquid ammonia and the air compressed by the first compressor.
6. The power generation system according to any one of claims 1 to 5, wherein the at least one heat exchanger is arranged in the second heat transfer medium flow path and exchanges heat between the liquid ammonia and the waste heat of the generator.
7. The power generation system according to any one of claims 1 to 6, wherein the at least one heat exchanger is arranged in the lubricating oil flow path and exchanges heat between the liquid ammonia and the waste heat of the gas turbine.
8. The power generation system according to any one of claims 1 to 7, wherein a blowdown water discharge section for discharging blowdown water generated from the steam turbine is connected to the first heat transfer medium flow path, and at least one heat exchanger is positioned in the first heat transfer medium flow path between the steam turbine and the blowdown water discharge section to exchange heat between the liquid ammonia and the blowdown water.