Wind / buoyancy hybrid power generation device and wind / buoyancy hybrid power generation method

Abstract

To provide a power generation device that has less impact on natural environment, is less affected by climate, is excellent in energy efficiency, and has a low manufacturing cost, compared to conventional arts.SOLUTION: A wind / buoyancy hybrid power generation device comprises: (A) a wind power generation unit comprising a tower, a nacelle rotatably provided on an upper part of the tower around a central axis of the tower, a hub rotatably provided on an end part of the nacelle around an axis perpendicular to the central axis, at least one blade provided on the hub, and a first generator arranged inside the nacelle and connected to the hub; and (B) a buoyancy power generation unit comprising a water storage tank configured to store water, a fuel gas introduction unit, a fuel gas recovery unit located above a water surface of storable water, and a fuel gas discharge unit connected to the fuel gas recovery unit, as well as a bubble receiving unit, a belt connected to the bubble receiving unit, a rotor connected to the belt, and a second generator connected to the rotor.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a wind / buoyancy hybrid power generation device and a wind / buoyancy hybrid power generation method that combine wind power generation using wind and buoyancy power generation using air bubbles. [Background technology]

[0002] In recent years, it has become clear that thermal power generation requires large amounts of fossil fuels and emits large amounts of carbon dioxide, a cause of global warming. Nuclear power generation has various risks, and the enormous costs involved, including facility construction, decommissioning, and reprocessing, have raised doubts about its efficiency.

[0003] These energy and environmental issues have been attracting attention, and in 2015 the United Nations Summit adopted the 2030 Agenda for Sustainable Development (Sustainable Development Goals (SDGs)), calling for the use of renewable energy to replace conventional energy sources that have a large environmental impact.

[0004] However, there are many hurdles to overcome before renewable energy can replace conventional energy sources. Solar power generation is heavily affected by weather and cannot generate electricity at night. Conventional wind power generation has problems such as being unable to generate electricity when there is no wind and the amount of power generated being affected by wind speed. Conventional hydroelectric power generation has problems such as environmental destruction caused by dam construction and the amount of power generated being affected by rainfall and the amount of water stored.

[0005] In response to this, buoyancy power generation, which generates electricity by using the buoyancy of air bubbles to rotate a rotor in water, is being considered as a renewable energy source that is less affected by weather and has little impact on the environment.

[0006] As buoyancy power generation methods, a buoyancy power generation device (Patent Document 1) has been proposed, in which air bubbles are placed in a bucket with reduced water resistance and the buoyancy of the bubbles rotates a rotor, and a buoyancy power generation device (Patent Document 2) has been proposed, in which air bubbles are taken in by replacing water with air using a water wheel at the bottom of a tank. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 2019-138293 [Patent Document 2] Japanese Patent Application Laid-Open No. 2007-138883 Summary of the Invention [Problem to be solved by the invention]

[0008] However, the device in Patent Document 1 uses an air pump connected externally to the bottom of the device to generate bubbles, which requires other energy such as electricity to generate the bubbles, resulting in an energy efficiency problem in that the output energy from the buoyancy power generation device is less than the input energy to generate the bubbles.The device in Patent Document 2 uses a water wheel, which means that, like conventional hydroelectric power generation, the amount of power generated is affected by environmental destruction caused by dam construction, and by climate factors such as rainfall and water storage volume.

[0009] Another issue with buoyancy power generation devices is the manufacturing costs of the water tanks, which can be several tens of meters long and contain water and introduce air bubbles, or the structure that holds them.

[0010] Therefore, there is a demand for power generation devices that have less impact on the natural environment, are less affected by climate, are more energy efficient, and are less expensive to manufacture than ever before. [Means for solving the problem]

[0011] The gist of the present invention is as follows. (1)(A) Tower, a nacelle provided on the top of the tower so as to be rotatable around the central axis of the tower; a hub provided at an end of the nacelle so as to be rotatable around an axis perpendicular to the central axis; at least one blade mounted on the hub; and a first generator disposed within the nacelle and coupled to the hub; a wind power generation unit including: (B) a water tank configured to store water; a fuel gas inlet, a fuel gas recovery section located above the water surface of the storable water, and a fuel gas discharge section connected to the fuel gas recovery section; a bubble receiving section, a belt connected to the bubble receiving section, a rotating body connected to the belt, and a second generator connected to the rotating body A buoyancy power generation unit including A wind / buoyancy hybrid power generation device comprising: The water tank is common to the tower or fixed inside the tower; the fuel gas inlet is configured to be able to introduce pressurized fuel gas obtained by vaporizing liquefied gas into the water tank, the fuel gas recovery unit is configured to recover the fuel gas introduced into the water tank above a water surface that can be stored in the water tank, the fuel gas discharge unit is configured to be able to discharge the fuel gas recovered in the fuel gas recovery unit to the outside, generating electricity in the first generator using rotational energy of the blades and the hub that move when receiving wind; The bubbles of the fuel gas introduced from the fuel gas inlet into the water tank are received by the bubble receiver, and the buoyancy of the bubbles moves a belt connected to the bubble receiver, causing a rotor connected to the belt to rotate, thereby generating electricity with the second generator connected to the rotor. A hybrid wind / buoyancy power generation device. (2) The hybrid power generation system according to (1) above, wherein the first generator and the second generator are a common generator. (3)(A) Wind power generation including rotating a hub, which is provided at the end of a nacelle rotatably about a central axis of the tower at the top of the tower, rotatably about an axis perpendicular to the central axis, and at least one blade provided on the hub by wind force to generate electricity using a first generator disposed inside the nacelle and connected to the hub; (B) introducing pressurized fuel gas obtained by vaporizing liquefied gas into the water in the tower used as a water tank or into the water in a water tank fixed inside the tower to form bubbles in the water; Receiving the air bubbles in an air bubble receiving portion disposed inside the water tank; a belt connected to the bubble receiving section is moved by buoyancy of the bubbles, causing a rotor connected to the belt to rotate, and generating electricity with a second generator connected to the rotor; The fuel gas introduced into the water as the bubbles is collected above the water surface; and Discharging the recovered fuel gas to the outside. Including buoyancy power generation and Hybrid wind / buoyancy power generation methods, including: (4) The hybrid power generation method according to (3) above, wherein the first generator and the second generator are a common generator. [Effects of the Invention]

[0012] According to the present invention, it is possible to provide a power generating device that has less impact on the natural environment, is less affected by climate, is more energy efficient, and has lower manufacturing costs than conventional devices. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a schematic diagram showing the external configuration of an example of the hybrid power generation device. [Figure 2] FIG. 2 is a schematic diagram of the nacelle of the wind turbine generator. [Figure 3] FIG. 3 is a schematic cross-sectional view of an example of a buoyancy power generation unit. [Figure 4] FIG. 4 is a cross-sectional schematic view of another example of a buoyancy power generation unit. [Figure 5] FIG. 5 is a schematic cross-sectional view of another example of a buoyancy power generation unit. [Figure 6] FIG. 6 is a cross-sectional schematic view of an example of a bubble receiving section in a buoyancy power generation section. [Figure 7]FIG. 7 shows an example of a power generation system including this hybrid power generation device. DETAILED DESCRIPTION OF THE INVENTION

[0014] The present disclosure provides a wind / buoyancy hybrid power generation device including: (A) a wind power generation unit including a tower, a nacelle rotatably mounted on an upper portion of the tower around a central axis of the tower, a hub rotatably mounted on an end portion of the nacelle around an axis perpendicular to the central axis, at least one blade mounted on the hub, and a first generator disposed inside the nacelle and connected to the hub; and (B) a buoyancy power generation unit including a water tank configured to be able to store water, a fuel gas inlet, a fuel gas recovery unit located above the water surface of the storable water, and a fuel gas outlet connected to the fuel gas recovery unit, as well as an air bubble receiver, a belt connected to the air bubble receiver, a rotor connected to the belt, and a second generator connected to the rotor, wherein the water tank is common to the tower or is separate from the tower. The present invention relates to a wind / buoyancy hybrid power generation system, which is fixed inside a water tank, and the fuel gas inlet is configured to introduce pressurized fuel gas obtained by vaporizing liquefied gas into the water tank, the fuel gas recovery unit is configured to recover the fuel gas introduced into the water tank above the water surface of the water tank, and the fuel gas discharge unit is configured to discharge the fuel gas recovered by the fuel gas recovery unit to the outside, and the system generates electricity with the first generator using rotational energy of the blades and the hub that move in response to wind, receives bubbles of the fuel gas introduced into the water tank from the fuel gas inlet in the bubble receiver, receives bubbles in the bubble receiver, moves a belt connected to the bubble receiver by the buoyancy of the bubbles, rotates a rotor connected to the belt, and generates electricity with the second generator connected to the rotor. The overall configuration of the wind / buoyancy hybrid power generation system will be described with reference to the drawings.

[0015] 1 is a schematic external configuration diagram of a wind / buoyancy hybrid power generation system 1 according to one embodiment. As shown in Fig. 1, the hybrid power generation system 1 includes a wind power generation unit 100 and a buoyancy power generation unit 200 that is disposed to serve as a tower 16 for the wind power generation unit 100 or that is disposed within the tower 16.

[0016] The wind power generation unit 100 includes at least one blade 11 (for example, three), a hub 13, a rotor 12 configured from the blade 11 and hub 13, a nacelle 14, and a tower 16. A first generator 15 is provided inside the nacelle 14. The blades 11 are attached radially to the hub 13, and are configured so that when the blades 11 receive wind, the rotor 12 rotates, and the first generator 15 connected to the rotor 12 generates electricity. The first generator 15 is not particularly limited and can be a known one, and a hydrostatic transmission or a gear-type speed-up gear can be used.

[0017] In the embodiment shown in Figure 1, the rotor 12 is supported by a nacelle 14 provided above a tower 16. The tower 16 is also provided upright on a base structure 18 (such as a foundation structure or a floating structure) provided on water or land.

[0018] 2 shows a schematic diagram of the nacelle 14. The nacelle 14 includes a first generator 15, and may further include a gearbox 17, a blade pitch control device (not shown), a yaw control device (not shown), etc. The top of the nacelle 14 may include a wind vane (not shown) and an anemometer (not shown) for control purposes.

[0019] When a speed increaser is provided, at least one (for example, three) blades 11 generate lift when exposed to wind, which causes the hub 13 to rotate. The rotational force is transmitted by the main shaft and converted into high-speed rotation by the speed increaser, which then rotates the first generator 15 and generates electricity.

[0020] The material of the tower 16 can be the same as that of the towers of conventional wind power generation devices, and can be any material that can be used as a water tank for a buoyancy power generation unit or that can hold a water tank inside, such as steel. When the tower 16 is used as a water tank for a buoyancy power generation unit, the shape and material of the tower 16 can be any material that has a fuel gas inlet, a fuel gas recovery unit, and a fuel gas outlet, and has a pressure-resistant, sealed structure that can store water inside and does not leak gaseous fuel gas to the outside except from the fuel gas outlet.

[0021] The shape of the tower 16 can be similar to that of a conventional wind power generation device, as long as it is a shape suitable for use as a water tank for the buoyancy power generation unit or a shape capable of holding a water tank therein. The shape of the tower 16 can be, for example, a cylindrical shape, a rectangular parallelepiped shape, or a combination thereof. When the water tank for the buoyancy power generation unit is fixed inside the tower 16, the shape can be any shape suitable for holding the water tank, such as a cylindrical shape, a rectangular parallelepiped shape, or a combination thereof. The wind power generation unit 100 has a nacelle 14 rotatably mounted on the top of the tower 16 around the central axis of the tower 16, allowing the orientation of the nacelle 14 to be changed according to the wind direction. Therefore, from the perspective of strength independent of directionality, a cylindrical shape is preferred for the tower 16. When the tower 16 is used as a water tank for the buoyancy power generation unit, a cylindrical shape is preferred for the tower 16 from the perspective of pressure resistance.

[0022] The height (hub height), inner diameter (circle equivalent diameter), and wall thickness of the tower 16 can be similar to those of conventional wind power generation equipment, and may be any size that can be used as a water tank for a buoyancy power generation unit or that can hold a water tank inside. The circle equivalent diameter is the diameter of the smallest circle that can surround an object. The height of the tower 16 is, for example, 12 to 150 m, 40 to 130 m, or 80 to 110 m. The inner diameter of the tower 16 is, for example, 2 to 8 m, 2.5 to 7 m, or 3 to 6 m. The wall thickness of the tower 16 is, for example, 4 to 30 cm, 5 to 20 cm, or 6 to 10 cm.

[0023] At the end of the nacelle 14, a hub 13 is provided that is rotatable around an axis perpendicular to the central axis of the tower 16, and at least one blade 11 is provided on the hub 13. The length of the blade 11 can be similar to that of a blade of a conventional wind turbine generator, for example, 40 to 80 m.

[0024] The wind turbine generator 100 may have a first control unit. The first control unit may include a yaw control unit that changes the direction of the rotor 12 depending on the wind direction, and a blade pitch control unit for the blades 11 that changes the direction of the blades 11 to increase, decrease, or stop the rotation of the blades 11 when the wind is weak or strong. The first control unit may also have an information communication unit that is capable of wireless communication via the Internet or wired communication, and can monitor the status of the wind turbine generator and control the start / stop of the wind turbine generator from a remote terminal.

[0025] The hybrid power generation system 1 includes a buoyancy power generation unit 200. Conventional wind power generation systems have a low capacity utilization rate of around 20% due to factors such as the inability to generate power when there is no wind and the effect of wind speed on the amount of power generated. However, the hybrid power generation system 1 has a buoyancy power generation function in addition to the wind power generation function, so it can continue to generate power stably even when wind power generation is not possible, thereby improving the capacity utilization rate. The electricity generated by the hybrid power generation system 1 is boosted by a transformer and sent to a power transmission line, where it can be consumed in factories, homes, etc. With this system 1, peripheral equipment for power transmission and transformation, such as transformers, which are costly, can be shared between the wind power generation system and the buoyancy power generation system, which also offers significant cost benefits.

[0026] The fuel gas used in the buoyancy power generation unit 200 is pressurized fuel gas used in conventional systems such as LNG power plants, which vaporize liquefied gas and use it as fuel gas. Conventionally, to simplify the transportation of fuel gas from the production site to the consumption site or the handling of fuel gas, the produced gaseous fuel gas has been cooled and liquefied at the production site. Liquefying fuel gas requires a huge amount of energy and requires a huge amount of cost.

[0027] The buoyancy power generation unit 200 can generate electricity by utilizing part of the pressure generated when liquefied fuel gas is returned to a gaseous state. The buoyancy power generation unit 200 can utilize part of the energy used at the expense of liquefying fuel gas at the production site not only for combustion but also as buoyancy at the consumption site. In other words, liquefied fuel gas produced by applying energy to gaseous fuel gas at the production site can be used at the consumption site as a transport medium for pressure energy. Therefore, the buoyancy power generation unit 200 enables power generation with less impact on the natural environment, less influence from climate, and excellent energy efficiency compared to conventional methods. A power generation method using the buoyancy power generation unit 200 will be described with reference to the drawings.

[0028] Fig. 3 is a cross-sectional schematic diagram of an example of a buoyancy power generation unit 200. The buoyancy power generation unit 200 shown in Fig. 3 includes a box-shaped water tank 20. The buoyancy power generation unit 200 includes the water tank 20 configured to be able to store water 24, and further includes a fuel gas inlet 21, a fuel gas recovery unit 26 located above the water surface of the storable water 24, and a fuel gas discharge unit 22 connected to the fuel gas recovery unit 26. In the buoyancy power generation unit 200 shown in Fig. 1, the fuel gas inlet 21, the fuel gas recovery unit 26, and the fuel gas discharge unit 22 are provided in the water tank 20. The water tank 20 is either shared with the tower 16 or is held inside the tower 16.

[0029] The buoyancy power generation unit 200 also includes an air bubble receiving unit 30, a belt 40 connected to the air bubble receiving unit 30, a rotating body 50 that rotates in conjunction with the movement of the belt, and a second generator (not shown) connected to the rotating body 50. There may be one or more air bubble receiving units 30, and preferably there are more than one. In the buoyancy power generation unit 200 shown in FIG. 1 , the air bubble receiving unit 30, the belt 40 connected to the air bubble receiving unit 30, and the rotating body 50 connected to the belt are provided inside the water tank 20, and the second generator connected to the rotating body 50 may be located either inside or outside the water tank 20. Preferably, the second generator may be separate from the first generator 15, but is preferably common to them.

[0030] When the second generator is common to the first generator 15 (hereinafter also referred to as a common generator), the cost of the generator can be reduced. The common generator is preferably disposed in the nacelle and connected to the rotor 12 of the wind power generation unit and the rotating body 50 of the buoyancy power generation unit.

[0031] The buoyancy power generation unit preferably has a second control unit. The second control unit may be separate from the first control unit or may be integrated with the first control unit. The second control unit may include a power generation amount control unit that adjusts the overall power generation amount depending on the power generation amount of the wind power generation unit and the power generation amount of the buoyancy power generation unit.

[0032] The power generation control unit may control the transmission, clutch, or both that connects the rotor 12 of the wind power generation unit to the first generator 15, and the transmission, clutch, or both that connects the rotor of the buoyancy power generation unit to the second generator, so as to maintain a constant overall power generation. Alternatively, the power generation control unit may control the orientation of the rotor 12 of the wind power generation unit, the angle of the blades 11, or both, and the valve (on-off valve) connected to the fuel gas inlet 21 of the buoyancy power generation unit, so as to maintain a constant overall power generation. The two power generation control methods described above may be combined. Closing the valve (on-off valve) allows the gaseous fuel gas to be bypassed without being introduced into the water tank. Whether the first generator and the second generator are common or separate, the above power generation control can maintain a constant overall power generation. For example, even when wind power generation efficiency is low during calm or strong winds, the buoyancy power generation unit can generate stable power using the common generator, improving power generation efficiency.

[0033] Pressurized fuel gas is introduced into the water 24 through the fuel gas introduction section 21 to form bubbles 25. The formed bubbles 25 are received in the bubble receiving section 30, and the buoyancy of the bubbles 25 is used to move the belt 40 connected to the bubble receiving section 30. As the belt 40 moves, the rotor 50, which rotates in conjunction with the movement of the belt 40, rotates, and electricity is generated by a second generator connected to the rotor 50. At least two rotors 50 may be installed, one above the other, near the water surface and the other below near the fuel gas introduction section 21. The belt 40 may be arranged to make a full circle around at least two rotors 50 arranged vertically. The upper rotor 50 may be located above or below the water surface of the storable water 24. When the rotating body 50 arranged on the upper side is positioned below the water surface of the storable water 24, the action of the bubbles 25 and the bubble receiving portion 30 can generate a circulating flow in the storable water 24 along the direction of movement of the belt 40, thereby improving power generation efficiency.

[0034] The fuel gas emerging from the water surface of the water tank 20 is collected by the fuel gas collection unit 26 and discharged from the fuel gas discharge unit 22 connected to the fuel gas collection unit 26. The discharged fuel gas is used for power generation, etc., in a conventional system. The fuel gas collected by the fuel gas collection unit 26 can be discharged by being pushed out from the fuel gas discharge unit 22 by the pressure of the fuel gas continuously emerging from the water surface. The water tank 20 includes the fuel gas collection unit 26 configured to recover the fuel gas introduced into the water tank 20 above the water surface and within the water tank 20. This prevents water from overflowing from the fuel gas discharge unit 22 and allows water to remain in the water tank 20 even if the water level rises when fuel gas bubbles are introduced into the water tank 20 from the fuel gas introduction unit 21. Furthermore, the fuel gas discharge unit 22 can be connected to any position of the fuel gas collection unit 26 configured to recover the fuel gas above the water surface and within the water tank 20.

[0035] The shape and material of the water tank 20 shown in FIG. 1 are not particularly limited as long as it has a fuel gas inlet, a fuel gas recovery section, and a fuel gas outlet, can store water therein, and has a pressure-resistant sealed structure that prevents gaseous fuel gas from leaking to the outside except from the fuel gas discharge section. The material of the water tank 20 can be, for example, steel, which is used in conventional LNG tanks or conventional LNG conduits or piping (hereinafter collectively referred to as piping). The shape of the water tank 20 can be, for example, a cylindrical shape, a rectangular parallelepiped shape, or a combination thereof, with a cylindrical shape being preferred because of its high pressure resistance. The water tank 20 equipped with the fuel gas recovery section 26 therein has a cylindrical shape and a pressure-resistant sealed structure made of steel, thereby enabling pressurized gaseous fuel gas to be used more safely within the water tank 20 equipped with the fuel gas recovery section 26.

[0036] The fuel gas introduction unit 21 is configured with a valve (on-off valve) that can introduce fuel gas from an external pipe into the water tank 20 when a pressure higher than the water pressure inside the water tank 20 is applied from the external pipe connected to the fuel gas introduction unit 21, and that prevents water inside the water tank 20 from leaking to the external pipe connected to the fuel gas introduction unit 21. The buoyancy power generation unit preferably includes a control device that can open and close the valve. The valve can be opened and closed manually or electrically. When the valve is opened and closed electrically, power for operation may be obtained from an external source, but preferably power generated by the first generator, the second generator, or both may be used. By providing the water tank 20 with the fuel gas introduction unit 21 that includes the on-off valve, the buoyancy power generation unit can be operated continuously or intermittently without leaking water stored in the water tank 20 to the pipe outside the water tank 20. This means that the location of the device 1 is not limited to a location where high-pressure gas is continuously fed, but can be installed in any location that is equipped with a device for vaporizing liquefied gas.

[0037] The fuel gas introduction unit 21 can be located at the bottom of the water tank 20 and / or on a side of the water tank 20. The fuel gas introduction unit 21 located on the side of the water tank 20 is preferably movable horizontally. The fuel gas introduction unit 21, located relatively high on the side of the water tank 20, can be moved horizontally to introduce bubbles into the bubble receiver 30, located relatively high in the water tank 20. Buoyancy is proportional to the bubble volume (cubed bubble radius), while drag is proportional to the bubble cross-sectional area (squared bubble radius) and the square of the rising speed. Therefore, the larger the bubble radius, the greater the buoyancy. The closer to the water surface, the lower the water pressure, and the larger the bubbles become, resulting in greater buoyancy due to the bubbles. Therefore, when starting up the buoyancy power generation unit, introducing bubbles from the fuel gas introduction unit 21 located on the side of the water tank 20 allows for greater buoyancy to move the belt and start power generation. The fuel gas introduction unit 21 can be moved manually or electrically. When the fuel gas introduction section 21 is moved electrically, the power for operating it may be obtained from an external source, or it may be power generated by the first generator, the second generator, or both.

[0038] The water tank 20 may include one or more fuel gas introduction units 21. The multiple fuel gas introduction units 21 may be arranged horizontally at the bottom of the water tank 20 and / or vertically at the side of the water tank 20.

[0039] The pressure of the fuel gas introduced from the fuel gas introduction section 21 is greater than the water pressure at the fuel gas introduction section 21. The pressure of the fuel gas introduced from the fuel gas introduction section 21 is greater than the pressure of the fuel gas recovered in the fuel gas recovery section 26 plus a pressure corresponding to the depth from the water surface at which the fuel gas introduction section 21 is located.

[0040] For example, in a conventional LNG system, a natural gas system through which natural gas (NG) is sent to natural gas users such as power plants and factories includes a pipeline of approximately 1.7 MPa (17 atmospheres). When the present device 1 is combined with this conventional LNG system and the water depth of the water tank 20, with the fuel gas inlet 21 located at the bottom, is 20 meters, the pressure of the fuel gas introduced through the fuel gas inlet 21 is set to be greater than 19 atmospheres, which is 17 atmospheres plus 2 atmospheres corresponding to the water depth of 20 meters. When fuel gas having a pressure greater than 19 atmospheres is introduced through the fuel gas inlet 21 located at the bottom of the water tank 20, the fuel gas recovered by the fuel gas recovery unit 26 from the surface of the water 24 at a depth of 20 meters has a pressure greater than 17 atmospheres. This fuel gas at a pressure greater than 17 atmospheres can be sent directly or after being reduced in pressure to 17 atmospheres to users at the power plant or factory through the pipeline of the natural gas system of the conventional system. The pressure can be reduced by using a pressure reducing valve, by branching a portion of the fuel gas from the pipe that carries the fuel gas discharged from the fuel gas discharge part to another pipe, or by discharging the fuel gas to the outside. The branched or discharged gas may be used in a lower-pressure section of another system in a conventional LNG system, returned to the LNG tank to prevent negative pressure within the tank, or re-liquefied by heat exchange with LNG for reuse.

[0041] The pressure of the fuel gas introduced through fuel gas introduction section 21 is preferably at least 1 atmosphere, more preferably at least 2 atmospheres, and even more preferably at least 3 atmospheres higher than the water pressure at fuel gas introduction section 21. When the pressure of the fuel gas introduced through fuel gas introduction section 21 is the above-mentioned preferred pressure, it becomes easier to introduce a larger amount of fuel gas bubbles into water 24 from fuel gas introduction section 21. There is no particular upper limit to the pressure of the fuel gas introduced through fuel gas introduction section 21, but the higher the pressure of the fuel gas introduced through fuel gas introduction section 21, the more the amount of pressure reduction of the fuel gas discharged from the fuel gas discharge section must be increased, and the piping and water tank for transmitting the fuel gas must be structured to withstand higher pressures. Therefore, the upper limit is preferably within +5 atmospheres or +4 atmospheres of the water pressure at fuel gas introduction section 21.

[0042] In conventional systems, a vaporizer is used to vaporize liquid fuel gas. The pressure of the fuel gas introduced from the fuel gas inlet 21 can be the pressure of the fuel gas discharged from the vaporizer that vaporizes liquefied gas in conventional systems. For example, in a conventional LNG system, LNG at -162°C is sent to the vaporizer by an LNG pump in an LNG tank. After passing through the vaporizer, which uses seawater, the LNG becomes natural gas (NG) at room temperature, with a volume 600 times larger. The high-pressure natural gas (NG) produced by volume expansion during vaporization is reduced in pressure through a pressure reducing valve and sent through piping to a fuel gas user, such as a boiler. The pressure reducing valve can reduce the pressure of the high-pressure natural gas vaporized by the vaporizer according to the usage pressure of the user. The outlet pressure of the pressure reducing valve changes depending on the natural gas consumption in the user, and the pressure reducing valve control device controls this pressure. When the consumption of natural gas in the use section increases and the outlet pressure of the pressure reducing valve decreases, the pressure reducing valve control device opens the pressure reducing valve to increase the outlet pressure of the pressure reducing valve. Conversely, when the outlet pressure of the pressure reducing valve increases, the pressure reducing valve control device closes the pressure reducing valve to maintain the outlet pressure of the pressure reducing valve constant.

[0043] This device 1 can be installed between the vaporizer and the fuel gas usage section such as a boiler in a conventional system. The pressure of the fuel gas introduced from the fuel gas inlet section 21 can be adjusted by a pressure reducing valve.

[0044] Conventionally used LNG vaporizers regasify LNG by applying latent heat of vaporization and sensible heat ranging from -162°C to room temperature. Vaporizers include, for example, conventional open-rack vaporizers, emergency submerged-type vaporizers, and intermediate heat transfer vaporizers. For example, in an open-rack vaporizer, LNG pumped by an LNG pump passes through a panel consisting of a rack of multiple vertically finned tubes. The LNG is heated by seawater flowing down the outer surface of the tubes, evaporating and heating the LNG, which is then discharged as gas from the upper header. The pressure of the fuel gas at the vaporizer outlet is controlled by controlling the flow rate of the liquid side of the vaporizer inlet. Therefore, the flow rate of the liquid side of the vaporizer inlet may be controlled to adjust the pressure of the fuel gas at the vaporizer outlet to the desired pressure required by the fuel gas introduction section 21.

[0045] The depth of the water stored in the water tank can be adjusted depending on the number of bubble receiving units and the pressure of the introduced fuel gas, but is preferably 10 m or more, more preferably 20 m or more, even more preferably 30 m or more, even more preferably 50 m or more, and even more preferably 100 m or more. The deeper the water, the more bubble receiving units can be installed, and the more buoyancy caused by the bubbles can be utilized. However, the deeper the water, the higher the water pressure at the bottom of the water tank, so fuel gas of a higher pressure must be introduced. Furthermore, the deeper the water, the smaller the volume of the bubbles and the smaller the generated buoyancy. Therefore, it is preferable that the second generator has a torque adjustment function that can reduce or zero the torque so that the belt can move even with small buoyancy at the initial start.

[0046] 1 may be determined according to the depth of the water stored therein, but may be a height that allows for the installation of a fuel gas inlet, a fuel gas recovery section, and a fuel gas outlet section, as well as an air bubble receiver, a belt connected to the air bubble receiver, a rotor connected to the belt, and, if desired, a second generator connected to the rotor. The height of the water tank is, for example, 12 to 150 m.

[0047] The bubble receiving portion 30 may have any structure capable of receiving fuel gas bubbles and moving the belt, but is preferably made of a lightweight material that is resistant to corrosion by water and fuel gas. The bubble receiving portion 30 is preferably made of stainless steel, aluminum, titanium, or a combination thereof.

[0048] The bubble receiving portion 30 may be, for example, a cube, a rectangular parallelepiped, or a hemisphere with a diameter. The dimensions of the bubble receiving portion 30 are not particularly limited, but may be, for example, a cube with a length, width, and dimension of 1 m, or a hemisphere with a radius of 1 m.

[0049] The air bubble receiving units 30 preferably have a capacity for receiving air bubbles that allows the buoyancy of the air bubbles 25 received by the lowest air bubble receiving unit 30 to move the belt 40 connected to the air bubble receiving unit 30 and rotate the rotor 50 connected to the belt 40, and more preferably, the capacity for receiving air bubbles that allows the buoyancy of the air bubbles 25 received by the lowest air bubble receiving unit 30 to move the belt 40 connected to the air bubble receiving unit 30 and rotate the rotor 50 connected to the belt 40, and generate electricity in a second generator connected to the rotor 50. The capacity for receiving air bubbles of the air bubble receiving units 30 is preferably 0.1 to 10 m 3 The density of water is about 1000 kg / m 3 As such, when one air bubble receiving section having the above-mentioned preferable receivable volume is filled with air bubbles, a buoyancy of 980 to 98,000 N (100 to 10,000 kg) is obtained.

[0050] The intervals between the multiple bubble receiving sections 30 connected to the belt 40 may be any interval that allows the bubble receiving sections 30 to rotate together with the belt 40 and sequentially receive the bubbles 25 introduced from the fuel gas introduction section 21. The intervals between the multiple bubble receiving sections 30 connected to the belt 40 are preferably such that each bubble receiving section 30 rotating at a steady speed together with the belt 40 can receive preferably 70% or more, more preferably 80% or more, and even more preferably 90% or more of the capacity of each bubble receiving section 30 to receive bubbles for the bubbles 25.

[0051] At least some of the bubble receiving sections 30 may have through-holes 31, as shown in FIG. 5 . By providing the through-holes 31, the bubble receiving sections 30 can receive buoyancy from the bubbles 25 introduced from the fuel gas introduction section 21 and introduce some of the bubbles 25 to other bubble receiving sections located above. At the bottom of the water tank, the water pressure is high and the bubbles are small, so the buoyancy of the bubbles 25 is relatively small. However, at the top of the water tank where the water pressure is low, the bubbles 25 expand in volume and their buoyancy increases. Therefore, by introducing the bubbles 25 to higher bubble receiving sections 30, the buoyancy of the buoyancy power generation unit can be increased. The position of the through-holes 31 is not particularly limited as long as it is a location that receives the bubbles in the bubble receiving sections 30, but the upper region of the bubble receiving sections 30, where bubbles tend to collect, is preferred. The size of the through-holes 31 may be the same as the diameter of the bubbles 25 introduced from the fuel gas introduction part 21, or may be smaller than the bubbles 25, or may be larger than the bubbles 25. The size of the through-holes 31 can be set to a size that allows the bubbles to move to higher bubble receiving parts 30 while the bubble receiving parts 30 are subjected to buoyancy, depending on the total volume of the bubbles 25 that are successively introduced into the water 24 and received by the bubble receiving parts 30.

[0052] The through-hole 31 is preferably openable and closable, and more preferably, the degree of opening is adjustable. The degree of opening refers to the degree to which the through-hole 31 is open. The through-hole 31 may be open in a region near the bottom of the water tank and closed in a region near the top of the water tank. The through-hole 31 may be half-open in a region near the center of the water tank. The buoyancy power generation unit preferably includes a control unit that opens and closes the through-hole 31. The second control unit may also include a control unit that opens and closes the through-hole 31. The through-hole 31 can be opened and closed manually or electrically. When the through-hole 31 is opened and closed electrically, power for operation may be obtained from an external source, but preferably power generated by the first generator, the second generator, or both may be used.

[0053] The shapes and dimensions of the multiple bubble receiving sections 30 may be different from one another. When the horizontal dimensions of some of the multiple bubble receiving sections 30 are larger than the horizontal dimensions of the other bubble receiving sections 30, bubbles that overflow from the lower bubble receiving sections 30 with smaller horizontal dimensions can be captured by the upper bubble receiving sections 30 with larger horizontal dimensions.

[0054] The belt 40 is at least partially placed in water, connected to the bubble receiving section 30, and has a configuration that can move the rotating body 50, and can be a metal chain belt, a rubber belt, etc.

[0055] The rotating body 50 may be any rotating body used in conventional generators as long as it has a structure that transmits the force of the belt to the second generator.

[0056] The second generator can be a conventional generator. Preferably, the second generator has a torque adjustment function. When starting the buoyancy power generation unit, the bubbles introduced into the water tank from the fuel gas inlet are located at the bottom of the water tank, where the buoyancy of the bubbles is relatively small. The buoyancy of the bubbles increases as the bubble receiver is raised while moving the belt connected to the bubble receiver. Therefore, the torque of the second generator can be increased. Preferably, the first generator, the second generator, or both are connected to a power storage device. This allows electricity generated by the generators to be stored in the power storage device, and the stored electricity can be used to start the device 1 or transmitted to an external device when needed.

[0057] The fuel gas introduction section 21 of the buoyancy power generation section 200 can be connected to a vaporization section 70 that is connected to a storage container for liquefied gas in a conventional system. The vaporization section 70 is configured to vaporize the liquefied gas to generate fuel gas and to transport the vaporized fuel gas to the fuel gas introduction section 21.

[0058] The fuel gas discharge section 22 of the buoyancy power generation section 200 can be connected to a fuel gas usage section 80 in a conventional system. For example, in LNG power generation in a conventional system, the usage section 80 can be a boiler, a turbine, or a combination thereof in steam power generation, gas turbine power generation, or combined cycle power generation.

[0059] The water tank 20 may be U-shaped as shown in FIG. 4. FIG. 4 is a cross-sectional schematic diagram of another example of a buoyancy power generation unit. The buoyancy power generation unit 200 shown in FIG. 4 includes a bubble receiving unit 30, a belt 40 connected to the bubble receiving unit 30, a rotor 50 connected to the belt, and a second generator (not shown) connected to the rotor 50. In the buoyancy power generation unit 200 shown in FIG. 4, one of a portion of the belt 40 connected to the bubble receiving unit 30 and the rotor 50 connected to the belt is disposed inside the water tank 20, and the other portion of the rotor 50 is provided outside the water tank 20 and inside a wall 60. The second generator connected to the rotor 50 may be disposed either inside or outside the wall 60. The wall 60 may be common with the tower 16 or may be held within the tower 16.

[0060] When the water tank 20 is U-shaped as shown in Fig. 4, the fuel gas inlet 21 is provided in the water tank 20, and the fuel gas can be collected in a fuel gas recovery section 26 formed by a wall section 60 surrounding at least the upper part of the water tank 20, and the fuel gas can be discharged from a fuel gas discharge section 22 provided in the wall section 60. The shape and material of the wall section 60 are not particularly limited as long as it includes the water tank 20, the fuel gas recovery section, and the fuel gas discharge section, and has a pressure-resistant sealed structure that does not leak gaseous fuel gas to the outside except from the fuel gas discharge section. The material of the wall section 60 can be, for example, steel, which is used in conventional LNG tanks or piping.

[0061] The wall 60 preferably has at least one stage of partitions 61 inside the wall 60 at a position where the fuel gas released from the surface of the water 24 can be collected between the wall 60 and the partitions 61 and discharged from the fuel gas discharge section 22. The wall 60 shown in FIG. 4 has two stages of partitions 61. The wall 60 and the uppermost partition 61 can form the fuel gas recovery section 26, so that the fuel gas can be discharged more efficiently from the fuel gas discharge section 22. The partitions 61 can also be used as scaffolding for inspecting the buoyancy power generation unit.

[0062] The water tank 20 in Figure 4 is not particularly limited as long as it has a fuel gas inlet 21 and is configured to be able to store water 24 inside, and can be made of steel, for example, which is used in conventional LNG tanks or piping.

[0063] The height of the water tank 20 in FIG. 4 may be determined according to the depth of the water 24 stored therein. However, it may be a height sufficient to accommodate the fuel gas introduction section 21, the bubble receiving section 30, at least a portion of the belt 40 connected to the bubble receiving section, and one of the rotors 50. The buoyancy power generation section 200 may be provided, between the wall 60 and the fuel gas recovery section 26, the other rotor 50 connected to the belt, and, optionally, a second generator connected to the rotor. The width of each U-shaped portion of the water tank 20 may be set to provide sufficient space for smooth water movement between the bubble receiving section 30 and the water tank so that resistance from the water is reduced when the bubble receiving section 30 is moved through the water tank. The width of the water tank is preferably at least 1.2 times, more preferably at least 1.3 times, even more preferably at least 1.4 times, and even more preferably at least 1.5 times the width of the bubble receiving section 30. The same applies to the width of the water tank shown in FIG. 5 below. The height of the water tank is, for example, 12 to 150 m. The other configuration of the buoyancy power generation unit shown in FIG.

[0064] The water tank 20 may have an O-shaped cross section as shown in Fig. 5. Fig. 5 is a cross-sectional schematic diagram of another example of a buoyancy power generation unit. The buoyancy power generation unit 200 shown in Fig. 5 includes a cylindrical, for example pipe-shaped, water tank 20 configured to be able to store water. The pipe shape may be flat, curved, or a combination thereof. The buoyancy power generation unit 200 further includes a fuel gas introduction unit 21, a fuel gas recovery unit 26, and a fuel gas discharge unit 22. In the buoyancy power generation unit 200 shown in Fig. 5, the fuel gas introduction unit 21, the fuel gas recovery unit 26, and the fuel gas discharge unit 22 are provided in the water tank 20.

[0065] The buoyancy power generation unit 200 also includes an air bubble receiving unit 30, a belt 40 connected to the air bubble receiving unit 30, a rotor 50 connected to the belt, and a second generator (not shown) connected to the rotor 50. There may be one or more air bubble receiving units 30, and preferably there are more than one. In the buoyancy power generation unit 200 shown in Figure 5, the air bubble receiving unit 30, the belt 40 connected to the air bubble receiving unit 30, and the rotor 50 connected to the belt are provided in the water tank 20, and the second generator connected to the rotor 50 may be located either inside or outside the water tank 20.

[0066] In the buoyancy power generation unit 200 illustrated in Figure 5, the introduction of pressurized gaseous fuel gas, the formation of bubbles 25, the operation of belt 40, the rotation of rotor 50, the generation of electricity by the second generator, the recovery and discharge of fuel gas, and other configurations are the same as those of the buoyancy power generation unit illustrated in Figure 3.

[0067] The present disclosure also provides a wind power generation system including: (A) a wind turbine that generates electricity by rotating a hub, which is provided at an end of a nacelle that is provided at an upper part of a tower so as to be rotatable around a central axis of the tower, and at least one blade provided on the hub, by wind force to generate electricity using a first generator that is disposed inside the nacelle and connected to the hub; and (B) a wind turbine that introduces pressurized fuel gas obtained by vaporizing liquefied gas into water in the tower that is used as a water tank or into water in a water tank fixed inside the tower. and buoyancy power generation, which includes forming bubbles in the water, receiving the bubbles in a bubble receiving section arranged inside the water tank, moving a belt connected to the bubble receiving section by the buoyancy of the bubbles to rotate a rotor connected to the belt and generate power with a second generator connected to the rotor, recovering the fuel gas introduced into the water as the bubbles above the water surface, and discharging the recovered fuel gas to the outside.

[0068] The fuel gas used in the buoyancy power generation unit and buoyancy power generation method of the present disclosure is preferably natural gas, propane gas, hydrogen gas, or ammonia gas. Liquefied versions of these fuel gases are liquefied natural gas, liquefied propane gas, liquefied hydrogen gas, or liquefied ammonia gas.

[0069] Liquefied natural gas (hereinafter referred to as LNG) is natural gas, a gaseous fuel gas, that has been cooled to -162°C, condensed, and reduced to 1 / 600 of its volume for transportation. It is a relatively clean fossil fuel, emitting less CO2 and nitrogen oxides when burned than other fossil fuels.

[0070] Natural gas is used as the main raw material for city gas, and is stored and transported as LNG, liquefied by cooling it to -162°C. In conventional LNG power generation, LNG is transported from overseas using LNG ships such as dedicated tankers and stored in dedicated LNG tanks at LNG terminals. The LNG sent out from the LNG tanks is vaporized by passing through a vaporizer and used as room-temperature natural gas for power generation, etc.

[0071] In conventional LNG power generation, high-temperature, high-pressure steam is generated by burning natural gas (NG) vaporized from LNG. This steam is then used to turn the impeller of a steam turbine, which then drives a second generator connected to the turbine, generating electricity.

[0072] Figure 7 shows an example of a hybrid power generation system for wind power generation and LNG power generation that incorporates the hybrid power generation apparatus of the present disclosure. In the hybrid power generation system shown in Figure 7, LNG is stored in an LNG tank 82 from an LNG carrier 81 via arm loading and piping. The LNG at -162°C is sent from the LNG tank 82 by an LNG pump to a vaporization unit 70, where it becomes room-temperature natural gas (NG) and is sent through piping to a buoyancy power generation unit of the hybrid power generation apparatus 1. In the vaporization unit 70, seawater is made to flow over the outer surface of the heat transfer tube of the vaporizer, vaporizing the LNG inside the vaporizer.

[0073] The natural gas (NG) used for buoyancy power generation in the buoyancy power generation unit 200 is sent to a natural gas user 80 such as a power plant or factory. The heat from burning the natural gas (NG) in the boiler of the power plant or factory generates high-temperature, high-pressure steam, which is used to turn the impeller of a steam turbine, which drives a generator connected to the turbine and generates electricity.

[0074] The location of this hybrid power generation system is not particularly limited and can be on land or offshore, as long as there is wind suitable for wind power generation and there is equipment for vaporizing liquefied gas such as LNG, but it can also be a port or coast where tankers carrying liquefied gas dock, or a location adjacent to a power generation system that uses liquefied gas or a power plant that uses liquefied gas.

[0075] As described above, this hybrid power generation system can reuse part of the energy used when natural gas (NG) is cooled and condensed to produce LNG. This hybrid power generation system can also reuse part of the energy used during liquefaction in conventional systems that use liquefied fuel gases other than LNG, such as liquefied propane gas (LPG), liquefied hydrogen gas, and liquefied ammonia gas. [Explanation of symbols]

[0076] 1 Hybrid power generation equipment 100 Wind Power Generation Department 11 Blades 12 rotors 13. Hub 14 Nacelle 15 First Generator 16. Tower 17 Gearbox 18 Foundation structure 200 Buoyancy Power Generation Unit 20 Water Tank 21 Fuel gas inlet 22 Fuel gas exhaust section 24 water 25 Bubbles 26 Fuel gas recovery section 30 Air bubble receiving section 31 Through hole in air bubble receiving section 40 Belt 50 Rotating Body 60 Wall 61 Partition 70 Vaporization section 80 Used part 81 LNG carriers 82 LNG tanks

Claims

1. (A) Tower, a nacelle provided on the top of the tower so as to be rotatable around the central axis of the tower; a hub provided at an end of the nacelle so as to be rotatable around an axis perpendicular to the central axis; at least one blade provided on the hub; and a first generator disposed within the nacelle and coupled to the hub; a wind power generation unit including: (B) a water tank configured to be able to store water; a fuel gas inlet, a fuel gas recovery section located above the water surface of the storable water, and a fuel gas discharge section connected to the fuel gas recovery section; a bubble receiving section, a belt connected to the bubble receiving section, a rotating body connected to the belt, and a second generator connected to the rotating body A buoyancy power generation unit including A wind / buoyancy hybrid power generation system comprising: The water tank is common to the tower or fixed inside the tower; the fuel gas inlet is configured to be able to introduce pressurized fuel gas obtained by vaporizing liquefied gas into the water tank, the fuel gas recovery unit is configured to recover the fuel gas introduced into the water tank above a water surface that can be stored in the water tank, the fuel gas discharge unit is configured to be able to discharge the fuel gas recovered in the fuel gas recovery unit to the outside, generating electricity in the first generator using rotational energy of the blades and the hub that move when receiving wind; The bubbles of the fuel gas introduced into the water tank from the fuel gas inlet are received by the bubble receiver, and the buoyancy of the bubbles moves a belt connected to the bubble receiver, causing a rotor connected to the belt to rotate, thereby generating electricity with the second generator connected to the rotor. A hybrid wind / buoyancy power generation device.

2. 2. The hybrid power generation system according to claim 1, wherein the first generator and the second generator are common.

3. (A) Wind power generation including: a nacelle provided at the top of a tower rotatably around a central axis of the tower; a hub provided at an end of the nacelle rotatably around an axis perpendicular to the central axis; and at least one blade provided on the hub, which are rotated by wind force to generate electricity using a first generator disposed inside the nacelle and connected to the hub; (B) introducing pressurized fuel gas obtained by vaporizing liquefied gas into the water in the tower used as a water tank or into the water in a water tank fixed inside the tower to form bubbles in the water; Receiving the air bubbles in an air bubble receiving portion disposed inside the water tank; a belt connected to the bubble receiving section is moved by buoyancy of the bubbles, causing a rotor connected to the belt to rotate, and generating electricity with a second generator connected to the rotor; The fuel gas introduced into the water as the bubbles is collected above the water surface; and Discharging the recovered fuel gas to the outside. Including buoyancy power generation and A hybrid wind / buoyancy power generation method including:

4. The hybrid power generation method according to claim 3 , wherein the first generator and the second generator are a common generator.

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