Power generation system and method

Abstract

To provide a power generation system and a method that recover and effectively use cold of hydrogen.SOLUTION: A power generation system comprises: a first steam turbine to be driven by a first working medium; a first power generator for generating power by the first steam turbine; a first heat exchanger for heating liquid hydrogen by the first working medium discharged from the first steam turbine, and recovering cold; and a second heat exchanger for heating the first working medium cooled by the first heat exchanger, and supplying it to the first steam turbine.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] SUMMARY The present disclosure relates to power generation systems and methods. [Background technology]

[0002] It is being considered to use hydrogen gas as fuel in a power generation system that realizes carbon neutrality. Hydrogen is stored in a tank in the form of liquid hydrogen. Therefore, the liquid hydrogen stored in the tank is vaporized by a vaporizer to produce hydrogen gas, which is used, for example, in a power generation system using a hydrogen gas turbine. At this time, there is a demand to recover cold energy when vaporizing the liquid hydrogen by the vaporizer and to effectively utilize the recovered cold energy. Note that, for example, a technology described in Patent Document 1 is an example of a power generation system that uses the cold energy of liquefied natural gas. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2000-204909 A Summary of the Invention [Problem to be solved by the invention]

[0004] Liquid hydrogen has a boiling point of -253°C at atmospheric pressure (1 atm), and a vaporizer is required to heat the liquid hydrogen at -253°C to vaporize it. When vaporizing liquid hydrogen, air or seawater is generally used as a heating medium. However, in this case, a large amount of the recovered cold energy is discarded, which poses an issue of poor energy efficiency. Note that the technology in Patent Document 1 targets liquefied natural gas, which has a boiling point of -162°C, and this boiling point is significantly different from that of hydrogen, making it difficult to use for hydrogen.

[0005] The present disclosure is devised to solve the above-mentioned problems, and has an object to provide a power generation system and method for recovering and effectively utilizing the cold energy of hydrogen. [Means for solving the problem]

[0006] In order to achieve the above-mentioned objective, the power generation system of the present disclosure includes a first steam turbine driven by a first working medium, a first generator that generates power using the first steam turbine, a first heat exchanger that heats liquid hydrogen using the first working medium discharged from the first steam turbine to recover cold energy, and a second heat exchanger that heats the first working medium cooled by the first heat exchanger and supplies it to the first steam turbine.

[0007] In addition, the power generation method disclosed herein includes the steps of heating liquid hydrogen with a first working medium, heating the first working medium that has been cooled by heating the liquid hydrogen, driving a first steam turbine with the heated first working medium, and generating power with the first steam turbine. Effect of the Invention

[0008] According to the power generation system and method disclosed herein, the cold energy of hydrogen can be recovered and effectively utilized. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic configuration diagram showing a power generation system according to the first embodiment. [Diagram 2] FIG. 2 is a schematic configuration diagram showing the first power generation system of the first embodiment. [Diagram 3] FIG. 3 is a schematic configuration diagram showing a power generation system according to the second embodiment. [Figure 4] FIG. 4 is a schematic configuration diagram showing a first power generation system according to the second embodiment. [Diagram 5] FIG. 5 is a schematic configuration diagram showing a first power generation system according to the third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Preferred embodiments of the present disclosure will be described in detail below with reference to the drawings. Note that the present disclosure is not limited to these embodiments, and when there are multiple embodiments, the present disclosure also includes a configuration in which each embodiment is combined. In addition, the components in the embodiments include those that a person skilled in the art can easily imagine, those that are substantially the same, and those that are within the so-called equivalent range.

[0011] [First embodiment] <Power generation system> FIG. 1 is a schematic configuration diagram showing a power generation system according to the first embodiment.

[0012] As shown in FIG. 1, the power generation system 10 includes a first power generation system 11 and a second power generation system 12.

[0013] The power generation system 10 recovers and effectively utilizes the cold energy generated when vaporizing liquid hydrogen. Specifically, the first power generation system 11 recovers the cold energy generated when vaporizing liquid hydrogen, cools a working medium with the recovered cold energy, and effectively utilizes the cooled working medium to generate various types of power. The second power generation system 12 effectively utilizes hydrogen gas generated by vaporizing liquid hydrogen to generate various types of power.

[0014] The hydrogen tank 13 stores a predetermined amount of liquid hydrogen (-253°C). The hydrogen tank 13 is connected to the first power generation system 11 by a path L1. A boost pump 14 is provided on the path L1. The boost pump 14 pressurizes the liquid hydrogen stored in the hydrogen tank 13 and supplies it to the first power generation system 11. The liquid hydrogen used in the power generation system 10 is not limited to that stored in the hydrogen tank 13. For example, the liquid hydrogen may be stored in a tank installed on a tanker. The first power generation system 11 heats and vaporizes the liquid hydrogen supplied from the path L1 to generate hydrogen gas. The first power generation system 11 also cools a working medium with the cold energy recovered when heating the liquid hydrogen, and generates power using the working medium.

[0015] The first power generating system 11 is connected to the second power generating system 12 via a path L2. The first power generating system 11 supplies the generated hydrogen gas to the second power generating system 12 via the path L2. The details of the first power generating system 11 will be described later.

[0016] The second power generation system 12 is a gas turbine combined cycle (GTCC) power generation system. The gas turbine combined cycle power generation system is a power generation method that combines a gas turbine and a steam turbine. The gas turbine combined cycle power generation system generates power by driving a gas turbine with combustion gas generated when fuel is burned, and further generates steam using heat from exhaust gas discharged from the gas turbine, and generates power by driving a steam turbine with the generated steam. The second power generation system 12 uses hydrogen gas as fuel for the gas turbine.

[0017] The second power generation system 12 has a hydrogen gas turbine 21, a generator (third generator) 22, a heat recovery steam generator 23, a steam turbine (second steam turbine) 24, and a generator (fourth generator) 25.

[0018] The hydrogen gas turbine 21 has a compressor 31, a combustor 32, and a turbine 33. The compressor 31 and the turbine 33 can rotate together by a rotating shaft 34. The generator 22 is connected to one axial end of the rotating shaft 34. A plurality of combustors 32 are arranged between the compressor 31 and the turbine 33 at intervals in the circumferential direction.

[0019] The compressor 31 is connected to a path L10. The compressor 31 compresses the air taken in from the path L10 by passing it through a plurality of stator blades and rotor blades, and generates high-temperature, high-pressure compressed air. The combustor 32 generates a mixture by supplying hydrogen gas, supplied as fuel gas from the path L2, to the compressed air generated by the compressor 31. The combustor 32 then burns the generated mixture to generate high-temperature, high-pressure combustion gas. The turbine 33 drives and rotates a rotating shaft 34 by the combustion gas passing through the stator blades and rotor blades, and discharges exhaust gas. The generator 22 is driven by the rotating shaft 34 being driven to rotate, and generates electricity.

[0020] The heat recovery steam generator 23 recovers heat from the exhaust gas flowing in from the hydrogen gas turbine 21 to generate steam. The heat recovery steam generator 23 has an exhaust stack 36, a boiler 37, and an economizer 38. The exhaust stack 36 is disposed, for example, along the horizontal direction, and one end in the longitudinal direction is connected to the turbine 33 of the hydrogen gas turbine 21, into which the exhaust gas flows. The boiler 37 is disposed upstream of the exhaust stack 36 in the flow direction of the exhaust gas, and the economizer 38 is disposed downstream of the exhaust stack 36 in the flow direction of the exhaust gas. The exhaust gas from the hydrogen gas turbine 21 flows in from one end in the longitudinal direction of the exhaust stack 36, and the heat-exchanged exhaust gas is discharged from the other end in the longitudinal direction.

[0021] The economizer 38 has an inlet connected to a path L11 for circulating and supplying hot water (or steam), and an outlet connected to a path L12 for discharging steam generated by heating the hot water. The economizer 38 generates steam by heating the hot water with exhaust gas from the hydrogen gas turbine 21. The boiler 37 is connected to a path L13 for supplying steam (e.g., 150°C) from the path L12 to a drum 37a. The boiler 37 superheats the steam supplied from the path L13 with the exhaust gas from the hydrogen gas turbine 21 to generate superheated steam.

[0022] The steam turbine 24 can be rotated by a rotating shaft 39. The rotating shaft 39 is connected to a generator 25 at one axial end. A path L14 from a drum 37a of a boiler 37 in the heat recovery steam generator 23 is connected to the steam turbine 24. The steam turbine 24 drives and rotates the rotating shaft 39 when superheated steam supplied from the boiler 37 through the path L14 passes through the stationary blades and the moving blades. The generator 25 is driven by the rotating shaft 39 being driven to generate electricity. The steam turbine 24 is also connected to the path L11 (or the path L12) through the path L15. The path L15 is provided with a condenser 26. The steam turbine 24 discharges used steam through the path L15 to the path L11 (or the path L12). The steam flowing through the path L15 is cooled by the condenser 26.

[0023] In the second power generation system 12, a hydrogen gas turbine 21 is driven by hydrogen gas as fuel, and generates electricity using a generator 22. In the second power generation system 12, a heat recovery boiler 23 recovers exhaust heat from the hydrogen gas turbine 21 to generate superheated steam, a steam turbine 24 is driven by the superheated steam, and electricity is generated using a generator 25.

[0024] <First power generation system> FIG. 2 is a schematic configuration diagram showing the first power generation system of the first embodiment.

[0025] 2, the first power generation system 11 includes a steam turbine (first steam turbine) 41, a generator (first generator) 42, a heat exchanger (first heat exchanger) 43, a liquid nitrogen storage tank 44, and a heat exchanger (second heat exchanger) 45. The steam turbine 41, the generator 42, the heat exchanger 43, the liquid nitrogen storage tank 44, and the heat exchanger 45 form a closed cycle in which nitrogen circulates as a first working medium. Note that the first working medium is not limited to nitrogen, and may be, for example, argon or the like.

[0026] The steam turbine 41 can be rotated by a rotating shaft 51. A generator 42 is coupled to one axial end of the rotating shaft 51. A path L21 is connected to the steam turbine 41. Nitrogen gas (e.g., 30°C) is supplied to the steam turbine 41 from the path L21. The steam turbine 41 drives the rotating shaft 51 to rotate as the nitrogen gas passes through the stationary blades and rotor blades. The generator 42 is driven by the rotating shaft 51 to rotate and generates electricity. The steam turbine 41 is connected to a heat exchanger 43 by a path L22.

[0027] The heat exchanger 43 exchanges heat between liquid hydrogen (e.g., −253° C.) supplied from the path L1 and nitrogen gas (e.g., −150° C.) supplied from the path L22. That is, the heat exchanger 43 heats liquid hydrogen with nitrogen gas discharged from the steam turbine 41 to recover cold heat. Specifically, the heat exchanger 43 heats liquid hydrogen supplied from the path L1 with nitrogen gas supplied from the steam turbine 41 through the path L22 to generate hydrogen gas (e.g., −100° C.) and discharges it to the path L2. The heat exchanger 43 also cools nitrogen gas supplied from the steam turbine 41 through the path L22 with liquid hydrogen supplied from the path L1 to generate liquid nitrogen (e.g., −200° C.).

[0028] The heat exchanger 43 is connected to a liquid nitrogen storage tank 44 via a path L23. The liquid nitrogen storage tank 44 receives liquid nitrogen generated by recovering cold energy by the heat exchanger 43 via the path L23 and stores the liquid nitrogen. The liquid nitrogen storage tank 44 is connected to the heat exchanger 45 via a path L24. A boost pump 52 is provided on the path L24. The boost pump 52 pressurizes the liquid nitrogen stored in the liquid nitrogen storage tank 44 and supplies it to the heat exchanger 45.

[0029] The heat exchanger 45 exchanges heat between liquid nitrogen (e.g., -200°C) supplied from the path L24 and nitrogen gas (e.g., 30°C) supplied from a path L31 described below. That is, the heat exchanger 45 heats the liquid nitrogen cooled by the heat exchanger 43 and supplies it to the steam turbine 41. Specifically, the heat exchanger 45 heats and gasifies the liquid nitrogen supplied from the path L24 using the nitrogen gas supplied from the path L31, generating nitrogen gas (e.g., 30°C) and discharging it to the path L21.

[0030] The first power generation system 11 also includes a compressor 61, a heat exchanger (fifth heat exchanger) 62, a gas turbine 63, a generator (second generator) 64, and a nitrogen gas tank 65. The compressor 61, the heat exchanger 62, the gas turbine 63, the generator 64, and the nitrogen gas tank 65 form a closed cycle in which nitrogen circulates as a second working medium. Note that the second working medium is not limited to nitrogen, and may be, for example, argon.

[0031] The compressor 61 and the gas turbine 63 can rotate together via a rotating shaft 71. A generator 64 is connected to one axial end of the rotating shaft 71. The compressor 61 is supplied with nitrogen gas (e.g., -150°C) from a path L32. The compressor 61 compresses the nitrogen gas to generate high-pressure nitrogen gas (e.g., 50°C). The compressor 61 is connected to a heat exchanger 62 via a path L33.

[0032] The heat exchanger 62 exchanges heat between the nitrogen gas (e.g., 50°C) supplied from the path L33 and the steam (e.g., 150°C) supplied from the path L12. That is, the heat exchanger 62 heats the nitrogen gas pressurized by the compressor 61 with the steam generated in the heat recovery boiler 23 (see FIG. 1) to generate high-temperature, high-pressure nitrogen gas (e.g., 120°C). The heat exchanger 62 is connected to the gas turbine 63 by the path L34. The steam whose temperature has been reduced by the heat exchange in the heat exchanger 62 is circulated back to the path L11 from the path L12.

[0033] The gas turbine 63 drives and rotates the rotating shaft 71 as the nitrogen gas from path L34 passes through the stationary blades and rotor blades. The rotating shaft 71 drives the compressor 61 as the rotating shaft 71 drives and rotates. The generator 64 is driven by the rotating shaft 71 to generate electricity. The gas turbine 63 is connected to a nitrogen gas tank 65 by path L35. Nitrogen gas (e.g., 30°C) discharged from the gas turbine 63 is supplied to the nitrogen gas tank 65 via path L35, and the nitrogen gas tank 65 stores the nitrogen gas. The nitrogen gas tank 65 is connected to the heat exchanger 45 by path L31.

[0034] As described above, the heat exchanger 45 exchanges heat between the liquid nitrogen supplied from the path L24 and the nitrogen gas supplied from the path L31. Specifically, the heat exchanger 45 cools the nitrogen gas supplied from the path L31 with the liquid nitrogen supplied from the path L24 to generate nitrogen gas (e.g., −150° C.) and discharges it to the path L32.

[0035] Furthermore, the first power generation system 11 has a heat exchanger (sixth heat exchanger) 81, a heat exchanger (seventh heat exchanger) 82, a Stirling engine 83, and a generator (fifth generator) 84. A third working medium circulating between the heat exchanger 81 and the Stirling engine 83 is nitrogen, argon, or the like. Also, a fourth working medium circulating between the heat exchanger 82 and the Stirling engine 83 is nitrogen, argon, or the like.

[0036] The Stirling engine 83 is an external combustion engine that applies high and low temperature heat from the outside of a sealed cylinder and uses the expansion and contraction of gas (pressure change) to operate a piston. The Stirling engine 83 has a high temperature side cylinder 91, a low temperature side cylinder 92, a first piston 93, a second piston 94, a crankshaft 95, and connecting shafts 96 and 97.

[0037] A first piston 93 is movably supported inside the high-temperature cylinder 91, and a second piston 94 is movably supported inside the low-temperature cylinder 92. The high-temperature cylinder 91 and the low-temperature cylinder 92 are internally connected. A crankshaft 95 is disposed along a direction perpendicular to the moving direction of the first piston 93 and the second piston 94, and is rotatably supported. The first piston 93 is connected to a crank portion of the crankshaft 95 by a connecting shaft 96, and the second piston 94 is connected to a crank portion of the crankshaft 95 by a connecting shaft 97. The connecting shafts 96, 97 are respectively connected to the crank portions of the crankshaft 95 in different rotation phases. The crankshaft 95 has a generator 84 connected to its axial end.

[0038] The heat exchanger 81 exchanges heat between hydrogen gas flowing through the path L2 and nitrogen gas (third working medium) circulating through the path L41. The heat exchanger 82 exchanges heat between steam flowing through the path L16 connected to the path L12 and nitrogen gas (fourth working medium) circulating through the path L42. The steam whose temperature has been reduced by the heat exchange in the heat exchanger 82 is returned to the path L11 and circulated. The third working medium and the fourth working medium are not limited to nitrogen gas.

[0039] That is, the heat exchanger 81 cools the nitrogen gas with hydrogen gas that has been heated and gasified by the heat exchanger 43, generating low-temperature nitrogen gas (e.g., 40°C). Meanwhile, the hydrogen gas is cooled by the heat exchanger 81 and its temperature rises (e.g., 30°C). Also, the heat exchanger 82 heats the nitrogen gas with steam generated in the exhaust heat recovery boiler 23 (see FIG. 1), generating high-temperature nitrogen gas (e.g., 70°C). The path L41 through which the low-temperature nitrogen gas flows is connected to one end of the high-temperature side cylinder 91, and the path L42 through which the high-temperature nitrogen gas flows is connected to the other end of the high-temperature side cylinder 91 and the low-temperature side cylinder 92.

[0040] Therefore, high-temperature nitrogen gas flowing through the path L32 acts on one end of the high-temperature cylinder 91, and the pressure of the expanded air acts on the first piston 93, moving the first piston 93 to one side (left side in FIG. 2). Low-temperature nitrogen gas flowing through the path L32 acts on the other end of the high-temperature cylinder 91, and the low-temperature air at the other end flows to the one end side. Then, the one end of the high-temperature cylinder 91 is cooled, the air contracts, and the first piston 93 moves to the other side (right side in FIG. 2). The second piston 94 also moves in the opposite direction in synchronization with the first piston 93. The linear motion of the first piston 93 and the second piston 94 is transmitted to the crankshaft 95 via the connecting shafts 96 and 97, and the crankshaft 95 rotates. When the crankshaft 95 is driven to rotate, the generator 84 is driven to generate electricity.

[0041] Further, a heat exchanger (fourth heat exchanger) 101 is provided downstream of the heat exchanger 81 in the path L2 through which the hydrogen gas flows. As shown in FIG. 1, the heat exchanger 101 is connected to the path L12 by the path L17, and is also connected to the path L11 by the path L18. The heat exchanger 101 exchanges heat between the hydrogen gas flowing through the path L2 and steam supplied from the path L17. That is, as shown in FIG. 2, the heat exchanger 101 heats the hydrogen gas with steam generated in the heat recovery boiler 23 (see FIG. 1) to increase the temperature (for example, to 90° C.). The heated hydrogen gas is supplied to the hydrogen gas turbine 21 (see FIG. 1).

[0042] <Power generation method> The power generation method of the first embodiment includes the steps of heating liquid hydrogen with nitrogen gas (first working medium), heating the nitrogen gas cooled by heating the liquid hydrogen, driving a steam turbine 41 with the heated nitrogen gas, and generating power with the steam turbine 41.

[0043] As shown in FIG. 1, the liquid hydrogen stored in the hydrogen tank 13 is boosted by the boost pump 14 and then supplied to the first power generation system 11 through the path L1. As shown in FIG. 2, the liquid hydrogen is heated by nitrogen gas in the heat exchanger 43 to become hydrogen gas, and is discharged to the path L2. At this time, the nitrogen gas recovers cold heat from the hydrogen gas in the heat exchanger 43 to become liquid nitrogen, and is temporarily stored in the liquid nitrogen storage tank 44. The liquid nitrogen stored in the liquid nitrogen storage tank 44 is boosted by the boost pump 52 and then supplied to the heat exchanger 45. The liquid nitrogen is heated by nitrogen gas in the heat exchanger 45 and then supplied to the steam turbine 41. The steam turbine 41 is driven by the supplied nitrogen gas, and the generator 42 generates electricity by obtaining driving force from the steam turbine 41. The steam turbine 41 returns the nitrogen gas after driving to the heat exchanger 43.

[0044] The nitrogen gas stored in the nitrogen gas tank 65 is supplied to the heat exchanger 45 via path L31. The nitrogen gas recovers cold energy from the liquid nitrogen flowing through path L24 in the heat exchanger 45, is compressed in the compressor 61, is heated in the heat exchanger 62, and is then supplied to the gas turbine 63. The gas turbine 63 is driven by the supplied nitrogen gas, and the generator 64 generates electricity by obtaining driving force from the gas turbine 63. The gas turbine 63 returns the nitrogen gas used for driving to the nitrogen gas tank 65.

[0045] The Stirling engine 83 obtains low-temperature heat from the hydrogen gas flowing through path L2, and obtains high-temperature heat from the steam flowing through path L12. That is, the Stirling engine 83 obtains low-temperature heat from the nitrogen gas flowing through path L31 from the heat exchanger 81, and obtains high-temperature heat from the nitrogen gas flowing through path L32 from the heat exchanger 62. In the Stirling engine 83, the first piston 93 and the second piston 94 are driven by the low-temperature heat and the high-temperature heat, driving and rotating the crankshaft 95, and the generator 84 obtains driving force from the crankshaft 95 to generate electricity.

[0046] The liquid hydrogen flowing through the path L1 is heated by the heat exchanger 43 to become hydrogen gas, and is then heated by the heat exchangers 81, 101 to increase its temperature. As shown in Fig. 1, the hydrogen gas generated by the first power generation system 11 is supplied to the hydrogen gas turbine 21 of the second power generation system 12. The hydrogen gas turbine 21 burns a mixture of air supplied through the path L10 and hydrogen gas supplied through the path L2 to generate combustion gas. The generator 22 obtains driving force from the hydrogen gas turbine 21 to generate electricity.

[0047] The heat recovery boiler 23 recovers heat from the exhaust gas from the hydrogen gas turbine 21 to generate steam (superheated steam). The superheated steam is supplied to the steam turbine 24 through a path L14. The steam turbine 24 is driven by the supplied superheated steam, and the generator 25 obtains driving force from the steam turbine 24 to generate electricity.

[0048] The power generation system 10 of the first embodiment recovers cold energy generated when liquid hydrogen is vaporized into hydrogen gas, and transfers the recovered cold energy to a working medium (liquid nitrogen / nitrogen gas) in multiple stages for use. The hydrogen gas and nitrogen gas are then used to drive a hydrogen gas turbine 21, steam turbines 24, 41, a gas turbine 63, and a Stirling engine 83, and power is generated by a plurality of generators 22, 25, 42, 64, 84. Therefore, the power generation system 10 can recover and effectively utilize the cold energy generated when liquid hydrogen is vaporized.

[0049] The power generation system 10 of the first embodiment generates hydrogen gas by heating liquid hydrogen, while recovering cold energy generated when the liquid hydrogen is vaporized. The generated hydrogen gas is used to generate power, and the recovered cold energy is used to generate power. Therefore, the power generation system 10 can efficiently generate power using hydrogen gas and nitrogen gas (working medium). The power generation system 10 recovers cold energy generated when the liquid hydrogen is vaporized in multiple stages, so that the power generation system 10 can effectively recover cold energy at a relatively low pressure ratio, and can avoid a decrease in aerodynamic performance and an increase in leakage loss due to a high pressure ratio, and can also recover cold energy from the hydrogen gas after the temperature rise in a single stage with an appropriate temperature difference and pressure ratio.

[0050] [Second embodiment] <Power generation system> 3 is a schematic diagram showing the configuration of a power generation system according to a second embodiment of the present invention, in which the same reference numerals are used to designate members having the same functions as those in the first embodiment described above, and detailed descriptions thereof will be omitted.

[0051] As shown in Fig. 3, the power generation system 10A includes a first power generation system 11A and a second power generation system 12. The second power generation system 12 is substantially similar to that in the first embodiment.

[0052] FIG. 4 is a schematic configuration diagram showing a first power generation system according to the second embodiment.

[0053] 4, the first power generation system 11A has a steam turbine (first steam turbine) 41A, a power generator 42, a heat exchanger 43, a liquid nitrogen storage tank 44, and a heat exchanger 45. The power generator 42, the heat exchanger 43, the liquid nitrogen storage tank 44, and the heat exchanger 45 are substantially similar to those in the first embodiment.

[0054] The steam turbine 41A has a first turbine 111 and a second turbine 112. The first turbine 111 and the second turbine 112 are supported coaxially. That is, the first turbine 111 and the second turbine 112 can rotate integrally by the same rotating shaft 51. The generator 42 is coupled to one end of the rotating shaft 51 in the axial direction.

[0055] The power generation system 10A also has a heat exchanger (eighth heat exchanger) 113. The heat exchanger 113 is provided on the path L10. The heat exchanger 113 cools the air supplied to the compressor 31 (see FIG. 1) of the hydrogen gas turbine 21 from the path L10 by using the nitrogen gas discharged from the first turbine 111.

[0056] The first turbine 111 is connected to a path L21. The first turbine 111 is supplied with nitrogen gas (e.g., 30°C) from the path L21. The first turbine 111 drives and rotates the rotating shaft 51 as the nitrogen gas passes through the stationary blades and the moving blades. The first turbine 111 is connected to a heat exchanger 113 by a path L25. The first turbine 111 supplies nitrogen gas (e.g., -80°C) to the heat exchanger 113 by the path L25. The heat exchanger 113 cools the air flowing through the path L10 with the nitrogen gas supplied from the path L25. The heat exchanger 113 is connected to the second turbine 112 by a path L26. The heat exchanger 113 supplies nitrogen gas (e.g., 30°C) to the second turbine 112 by the path L26. The second turbine 112 drives and rotates the rotating shaft 51 as the nitrogen gas passes through the stationary blades and the moving blades. The second turbine 112 is connected to the heat exchanger 43 by a path L22. The generator 42 is driven by the rotary shaft 51 being driven to rotate, and generates electricity.

[0057] The overall operation of the power generation system 10A is similar to that of the power generation system 10 of the first embodiment, and a description thereof will be omitted.

[0058] As in the first embodiment, the power generation system 10A of the second embodiment recovers the cold energy generated when liquid hydrogen is vaporized into hydrogen gas, and transfers the recovered cold energy to a working medium (liquid nitrogen / nitrogen gas) in multiple stages for use. The hydrogen gas and nitrogen gas are then used to drive the hydrogen gas turbine 21, steam turbines 24, 41A, gas turbine 63, and Stirling engine 83, and power is generated by the multiple generators 22, 25, 42, 64, and 84. Therefore, the power generation system 10A can recover and effectively utilize the cold energy generated during liquidization and vaporization.

[0059] Furthermore, in the power generation system 10A of the second embodiment, the steam turbine 41A of the first power generation system 11A is configured as multiple stages, and a heat exchanger 113 is provided to cool the air supplied to the hydrogen gas turbine 21. Therefore, the cold energy recovered during the vaporization of liquid hydrogen can be used to cool the air supplied to the hydrogen gas turbine 21, thereby achieving even more effective use of the cold energy. Furthermore, the output of the hydrogen gas turbine 21 can be improved by reducing the temperature of the air supplied to the hydrogen gas turbine 21.

[0060] [Third embodiment] <First power generation system> 5 is a schematic diagram showing a first power generation system of the third embodiment. The power generation system of the third embodiment is almost the same as that of the second embodiment described above, and a detailed description thereof will be omitted. The first power generation system of the third embodiment is a modification of the second embodiment, and members having the same functions as those of the second embodiment are denoted by the same reference numerals, and a detailed description thereof will be omitted.

[0061] As shown in Fig. 5, the power generation system 10B includes a first power generation system 11B and a second power generation system 12 (see Fig. 4). The second power generation system 12 is substantially similar to that in the second embodiment.

[0062] The first power generating system 11B includes a steam turbine 41A, a generator 42, a heat exchanger 43, a liquid nitrogen storage tank 44, and a heat exchanger 45. The first power generating system 11B is substantially similar to the second embodiment.

[0063] The first power generation system 11B also includes a compressor 61, a heat exchanger 62, a gas turbine 63, a generator 64, a nitrogen gas tank 65, and a heat exchanger (third heat exchanger) 121. The compressor 61, the heat exchanger 62, the gas turbine 63, the generator 64, and the nitrogen gas tank 65 are the same as those in the second embodiment.

[0064] The compressor 61 receives nitrogen gas from the path L32, compresses the nitrogen gas, and generates high-pressure nitrogen gas. The compressor 61 is connected to the heat exchanger 62 by the path L33, and the heat exchanger 62 exchanges heat between the nitrogen gas and steam supplied from the path L12. That is, the heat exchanger 62 heats the nitrogen gas pressurized by the compressor 61 with steam generated in the exhaust heat recovery boiler 23 (see FIG. 1), and generates high-temperature, high-pressure nitrogen gas. The heat exchanger 62 is connected to the gas turbine 63 by the path L34, and the gas turbine 63 drives and rotates the rotating shaft 71 by the nitrogen gas. The generator 64 is driven by the rotating shaft 71 to rotate, and generates electricity.

[0065] The gas turbine 63 is connected to a nitrogen gas tank 65 via a path L35. The nitrogen gas tank 65 is connected to a heat exchanger 121 via a path L36. The heat exchanger 121 exchanges heat between the nitrogen gas flowing through the path L2 and the nitrogen gas supplied from the path L36. That is, the heat exchanger 121 heats (for example, to 30° C.) the nitrogen gas flowing through the path L2 by the nitrogen gas supplied from the path L36. The heat exchanger 121 also cools the nitrogen gas supplied from the path L36 by the hydrogen gas flowing through the path L2. The heat exchanger 121 is connected to a heat exchanger 45 via a path L31. The heat exchanger 45 exchanges heat between the liquid nitrogen supplied from the path L24 and the nitrogen gas supplied from the path L31. Specifically, the heat exchanger 45 cools the nitrogen gas supplied from the path L31 by the liquid nitrogen supplied from the path L24 to generate nitrogen gas, which is then discharged to the path L32.

[0066] As in the second embodiment, the power generation system 10B of the third embodiment recovers the cold energy generated when liquid hydrogen is vaporized into hydrogen gas, and transmits the recovered cold energy to a working medium (liquid nitrogen / nitrogen gas) in multiple stages for use. The hydrogen gas and nitrogen gas are then used to drive the hydrogen gas turbine 21, steam turbines 24, 41A, and gas turbine 63, and power is generated by the multiple generators 22, 25, 42, 64, and 84. Therefore, the power generation system 10B can recover and effectively utilize the cold energy generated when liquid hydrogen is vaporized.

[0067] Moreover, in the power generation system 10B of the third embodiment, a heat exchanger 121 is provided in place of the Stirling engine 83 (see FIG. 4) in the first power generation system 11B. Therefore, the cold energy recovered during the vaporization of liquid hydrogen can be used to cool the nitrogen gas supplied to the gas turbine 63, thereby achieving even more effective use of the cold energy.

[0068] [Effects of this embodiment] The power generation system of the first embodiment includes a steam turbine (first steam turbine) 41, 41A driven by a first working medium, a generator (first generator) 42 that generates power using the steam turbine 41, 41A, a heat exchanger (first heat exchanger) 43 that heats liquid hydrogen using nitrogen gas (first working medium) discharged from the steam turbine 41, 41A to recover cold energy, and a heat exchanger (second heat exchanger) 45 that heats the nitrogen gas cooled by the heat exchanger 43 and supplies it to the steam turbine 41, 41A.

[0069] According to the power generation system of the first aspect, heat exchanger 43 heats liquid hydrogen with nitrogen gas to recover cold energy, and liquid nitrogen cooled in heat exchanger 45 is heated and supplied to steam turbines 41, 41A, which are driven by nitrogen gas to generate power in generator 42. Therefore, the cold energy of the liquid hydrogen can be used to generate power in generator 42 by steam turbines 41, 41A, and the cold energy of the liquid hydrogen can be recovered and effectively utilized.

[0070] The power generation system according to the second embodiment is the power generation system according to the first embodiment, further comprising: heat exchanger 73 heats liquid hydrogen to generate hydrogen gas, and recovers cold energy from the liquid hydrogen to liquefy nitrogen gas, and heat exchanger 45 gasifies liquid nitrogen. This makes it possible to effectively recover the cold energy of the liquid hydrogen by utilizing the temperature difference between the boiling points of liquid hydrogen and liquid nitrogen.

[0071] The power generation system according to the third aspect is the power generation system according to the first or second aspect, and further includes a liquid nitrogen storage tank 44 for storing liquid nitrogen liquefied by heat exchanger 43, and a boost pump 52 for pressurizing the liquid nitrogen stored in the liquid nitrogen storage tank 44 and supplying it to the heat exchanger 45. As a result, by temporarily storing the liquid nitrogen that has recovered the cold energy generated during the vaporization of liquid hydrogen in the liquid nitrogen storage tank 44, the recovered cold energy can be appropriately utilized.

[0072] The power generation system according to the fourth aspect is the power generation system according to any one of the first to third aspects, and further includes a compressor 61 that pressurizes nitrogen gas (second working medium), a gas turbine 63 driven by the nitrogen gas pressurized by the compressor 61, and a generator (second generator) 64 that generates power by the gas turbine 63, and the heat exchanger 45 cools the nitrogen gas discharged from the gas turbine 63 by the nitrogen gas cooled by the heat exchanger 45 and supplies the cooled nitrogen gas to the compressor 61. This makes it possible to drive the gas turbine 63 using cold energy generated during the vaporization of liquid hydrogen to generate power.

[0073] The power generation system according to the fifth embodiment is the power generation system according to the fourth embodiment, and further includes a heat exchanger (third heat exchanger) 121 that cools the nitrogen gas discharged from the gas turbine 63 by hydrogen gas that has been heated and gasified by the heat exchanger 43. This makes it possible to recover the cold energy of the hydrogen gas not only in the heat exchanger 43 but also in the heat exchanger 121.

[0074] A power generation system according to a sixth aspect is the power generation system according to the fourth or fifth aspect, further using nitrogen or argon as the first working medium and the second working medium, thereby making it possible to effectively recover the cold energy of the liquid hydrogen.

[0075] The power generation system according to the seventh aspect is the power generation system according to any one of the first to sixth aspects, and further includes a steam turbine 41A having a first turbine 111 and a second turbine 112 supported on the same shaft, the first turbine 111 being driven by nitrogen gas heated by a heat exchanger 45, and the second turbine 112 being driven by nitrogen gas heated after being discharged from the first turbine 111. This makes it possible to effectively utilize the cold energy of the liquid hydrogen, and improves the power generation efficiency by the steam turbine 41A and the generator 42.

[0076] The power generation system according to the eighth aspect is the power generation system according to any one of the first to seventh aspects, and further includes a hydrogen gas turbine 21 that uses hydrogen gas generated by heating liquid hydrogen in a heat exchanger 43 as fuel, and a generator (third generator) 22 that generates electricity using the hydrogen gas turbine 21. As a result, vaporized hydrogen gas is supplied to the hydrogen gas turbine 21 to drive it, thereby enabling efficient power generation.

[0077] The power generation system according to the ninth aspect is the power generation system according to the eighth aspect, and further includes a heat recovery boiler 23 that generates steam from exhaust gas from the hydrogen gas turbine 21, a steam turbine (second steam turbine) 24 that is driven by the steam generated by the heat recovery boiler 23, and a generator (fourth generator) 25 that generates electricity by the steam turbine 24. This makes it possible to increase the amount of power generation.

[0078] The power generation system according to the tenth aspect is the power generation system according to the ninth aspect, and further includes a heat exchanger (fourth heat exchanger) 101 that heats the hydrogen gas heated and gasified by the heat exchanger 43 with steam generated in the heat recovery boiler 23. This makes it possible to heat the hydrogen gas to a temperature at which it can be easily used.

[0079] The power generation system according to the eleventh aspect is the power generation system according to the ninth or tenth aspect, and further includes a compressor 61 that boosts the pressure of nitrogen gas, a heat exchanger (fifth heat exchanger) 62 that heats the nitrogen gas boosted by the compressor 61 with steam generated in the heat recovery boiler 23, a gas turbine 63 that is driven by the nitrogen gas heated by the heat exchanger 62, and a generator 64 that generates power with the gas turbine 63. As a result, the nitrogen gas is heated with the steam generated in the heat recovery boiler 23 and supplied to the gas turbine 63, so that the gas turbine 63 can be driven efficiently.

[0080] The power generation system according to the twelfth aspect is the power generation system according to any one of the ninth to eleventh aspects, and further includes a heat exchanger (sixth heat exchanger) 81 that cools nitrogen gas (third working medium) with hydrogen gas heated and gasified by the heat exchanger 43, a heat exchanger (seventh heat exchanger) 82 that heats nitrogen gas (fourth working medium) with steam generated in the heat recovery boiler 23, a Stirling engine 83 that drives a first piston 93 and a second piston 94 using low-temperature nitrogen gas and high-temperature nitrogen gas, and a generator (fifth generator) 84 that generates electricity with the Stirling engine 83. This allows the cold energy of the hydrogen gas to be recovered not only by the heat exchanger 43 but also by the Stirling engine 83.

[0081] The power generation system according to the thirteenth aspect is the power generation system according to any one of the eighth to twelfth aspects, and further includes a heat exchanger (eighth heat exchanger) 113 that cools the air supplied to the hydrogen gas turbine 21 with nitrogen gas discharged from the steam turbines 41, 41A. As a result, the air supplied to the hydrogen gas turbine is cooled by the cold heat of the liquid hydrogen, and the output of the hydrogen gas turbine 21 can be improved.

[0082] The power generation method according to the fourteenth aspect includes the steps of heating liquid hydrogen with a first working medium, heating nitrogen gas (first working medium) cooled by heating the liquid hydrogen, driving steam turbines (first steam turbines) 41, 41A with the heated nitrogen gas, and generating power with the steam turbines 41, 41A. This allows the steam turbines 41, 41A to generate power using the cold energy of the liquid hydrogen to generate power in the generator 42, and allows the cold energy of the hydrogen to be recovered and effectively utilized.

[0083] In the above-described embodiment, a gas turbine combined cycle having a hydrogen gas turbine 21 and a steam turbine 24 is used as a heat engine that uses hydrogen gas, but the present invention is not limited to this configuration. For example, a hydrogen gas turbine or a gas engine may be used as the heat engine.

[0084] In the above-described embodiment, the gas turbine 63 or the Stirling engine 83 is used as an engine that utilizes cold energy recovered by vaporizing liquid hydrogen, but the present invention is not limited to this configuration. For example, a gas engine or a steam turbine may be used as the engine. [Explanation of symbols]

[0085] 10, 10A, 10B Power generation system 11, 11A, 11B First power generation system 12 Second Power Generation System 13 Hydrogen Tank 14 Booster pump 21 Hydrogen Gas Turbine 22 Generator (3rd Generator) 23 Waste heat recovery boiler 24 Steam turbine (No. 2 steam turbine) 25 Generator (4th Generator) 26 Condenser 31 Compressor 32 Combustor 34 Rotational Axis 36 Exhaust stack 37 Boiler 38 Economizer 39 Rotational Axis 41, 41A Steam Turbine (No. 1 Steam Turbine) 42 Generator (1st Generator) 43 Heat exchanger (1st heat exchanger) 44 Liquid Nitrogen Storage Tank 45 Heat exchanger (second heat exchanger) 51 Rotation axis 52 Booster pump 61 Compressor 62 Heat exchanger (5th heat exchanger) 63 Gas Turbine 64 Generator (2nd Generator) 65 Nitrogen gas tank 71 Rotational Axis 81 Heat exchanger (6th heat exchanger) 82 Heat exchanger (7th heat exchanger) 83 Stirling Engine 84 Generator (5th Generator) 91 High temperature cylinder 92 Low temperature cylinder 93 First piston 94 Second piston 95 Crankshaft 96,97 Connecting shaft 101 Heat exchanger (4th heat exchanger) 111 First Turbine 112 No. 2 Turbine 113 Heat exchanger (8th heat exchanger) 121 Heat exchanger (third heat exchanger)

Claims

1. a first steam turbine driven by a first working medium; a first generator that generates electricity using the first steam turbine; a first heat exchanger that heats liquid hydrogen with the first working medium discharged from the first steam turbine to recover cold energy; a second heat exchanger that heats the first working medium cooled by the first heat exchanger and supplies the first working medium to the first steam turbine; A power generation system comprising:

2. The first heat exchanger heats liquid hydrogen to generate hydrogen gas and recovers cold heat from the liquid hydrogen to liquefy the first working medium, and the second heat exchanger gasifies the first working medium in a liquid state. The power generation system according to claim 1 .

3. a storage tank that stores the first working medium liquefied by the first heat exchanger, and a pump that pressurizes the first working medium stored in the storage tank and supplies the pressurized first working medium to the second heat exchanger, The power generation system according to claim 2 .

4. a compressor that pressurizes a second working medium, a gas turbine that is driven by the second working medium pressurized by the compressor, and a second generator that generates electricity by the gas turbine, The second heat exchanger cools the second working medium discharged from the gas turbine by the first working medium cooled by the first heat exchanger and supplies the cooled second working medium to the compressor. The power generation system according to any one of claims 1 to 3.

5. a third heat exchanger that cools the second working medium discharged from the gas turbine by hydrogen gas that has been heated and gasified by the first heat exchanger; The power generation system according to claim 4 .

6. The first working medium and the second working medium are nitrogen or argon. The power generation system according to claim 4 .

7. The first steam turbine has a first turbine and a second turbine supported on a same shaft, the first turbine is driven by the first working medium heated by the second heat exchanger, and the second turbine is driven by the first working medium heated after being discharged from the first turbine. The power generation system according to claim 1 .

8. a hydrogen gas turbine using hydrogen gas produced by heating the liquid hydrogen in the first heat exchanger as fuel; and a third generator that generates electricity using the hydrogen gas turbine. The power generation system according to claim 1 .

9. a heat recovery boiler that generates steam using exhaust gas from the hydrogen gas turbine, a second steam turbine that is driven by the steam generated by the heat recovery boiler, and a fourth generator that generates electricity using the second steam turbine. The power generation system according to claim 8 .

10. A fourth heat exchanger is provided for heating the hydrogen gas gasified by the first heat exchanger with the steam generated in the heat recovery boiler. The power generation system according to claim 9 .

11. a compressor that pressurizes a second working medium; a fifth heat exchanger that heats the second working medium pressurized by the compressor with the steam generated in the heat recovery boiler; a gas turbine that is driven by the second working medium heated by the fifth heat exchanger; and a second generator that generates electricity by the gas turbine. The power generation system according to claim 9 .

12. a sixth heat exchanger for cooling a third working medium by hydrogen gas heated and gasified by the first heat exchanger, a seventh heat exchanger for heating a fourth working medium by the steam generated in the heat recovery boiler, a Stirling engine for driving a first piston and a second piston by using the third working medium at a low temperature and the fourth working medium at a high temperature, and a fifth generator for generating electricity by the Stirling engine. The power generation system according to claim 9 .

13. an eighth heat exchanger that cools air supplied to the hydrogen gas turbine by the first working medium discharged from the first steam turbine; The power generation system according to claim 8 .

14. heating liquid hydrogen with a first working medium; heating the first working medium cooled by heating the liquid hydrogen; driving a first steam turbine with the heated first working medium; generating electricity with the first steam turbine; A power generation method comprising the steps of:

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