Cold heat recovery equipment and ships

Abstract

To provide a cold recovery facility and a ship that can recover cold energy from two kinds of liquid fuels while efficiently vaporizing the liquid fuels.SOLUTION: A cold recovery facility comprises a first fuel tank 10 for storing a first fuel in a liquid state, a second fuel tank 20 for storing a second fuel in a liquid state with a higher liquefaction temperature than that of the first fuel, a first circuit 32 constituted so that a first medium is circulated, a first expansion turbine 34 on the first circuit, a first heat exchanger 36 for condensing the first medium, a pump 38 for increasing the pressure of the first medium, a second heat exchanger 40 for evaporating the first medium on the downstream side of the pump, and a third heat exchanger 42 on the downstream side of the second heat exchanger. The first heat exchanger is constituted so as to vaporize the first fuel in the liquid state from the first fuel tank by exchanging heat between the first fuel and the first medium. The third heat exchanger is constituted so as to vaporize the second fuel in the liquid state from the second fuel tank by exchanging heat between the second fuel and the first medium.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a cold heat recovery facility and a ship. [Background technology]

[0002] Methods have been proposed for recovering and utilizing the cold energy of low-temperature liquid fuels such as liquefied natural gas (LNG).

[0003] Patent Document 1 describes a floating facility equipped with a power generation device that generates electricity using LNG cryogenics. This power generation device includes a thermodynamic cycle that uses a heat transfer medium as a working fluid, and generates electricity using a generator connected to an expansion turbine driven by the heat transfer medium (working fluid) flowing through a circuit. In this thermodynamic cycle, engine cooling water, seawater, or the like is used as a high-temperature heat source that exchanges heat with the heat transfer medium in an evaporator, and LNG is used as a low-temperature heat source that exchanges heat with the heat transfer medium in a condenser. After being vaporized (regasified) in the condenser, the LNG is supplied to equipment that uses natural gas as fuel, etc. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-147221 Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, it has been proposed to use liquid fuels other than LNG, such as liquid hydrogen (LH2), as fuel for ships, etc., and it is conceivable to use multiple liquid fuels, such as LNG and liquid hydrogen, in combination on ships, etc. In this way, when using two types of liquid fuels in combination, it is desirable to recover the cryogenic energy of the liquid fuels while efficiently vaporizing these two types of liquid fuels.

[0006] In view of the above circumstances, at least one embodiment of the present invention aims to provide a cold energy recovery system and a ship that can recover the cold energy of liquid fuels while efficiently vaporizing two types of liquid fuels. [Means for solving the problem]

[0007] At least one embodiment of the present invention relates to a cold heat recovery facility. a first fuel tank for storing a first fuel in a liquid state; a second fuel tank for storing a second fuel in a liquid state having a higher liquefaction temperature than the first fuel; a first circuit configured to circulate a first medium; a first expansion turbine provided on the first circuit for expanding the first medium in a gaseous state; a first heat exchanger provided on the first circuit downstream of the first expansion turbine for condensing the first medium; a pump provided on the first circuit downstream of the first heat exchanger for increasing the pressure of the first medium; a second heat exchanger provided on the first circuit downstream of the pump for evaporating the first medium; a third heat exchanger provided on the first circuit downstream of the second heat exchanger and upstream of the first expansion turbine, the first heat exchanger is configured to vaporize the first fuel by heat exchange between the first fuel in a liquid state from the first fuel tank and the first medium, The third heat exchanger is configured to vaporize the second fuel by heat exchange between the second fuel in a liquid state from the second fuel tank and the first medium.

[0008] Furthermore, a ship according to at least one embodiment of the present invention includes: The hull and The above-mentioned cold heat recovery equipment installed in the hull; a prime mover or a fuel cell provided in the hull and using the first fuel vaporized in the first heat exchanger and the second fuel vaporized in the third heat exchanger as fuel; Equipped with. [Effects of the Invention]

[0009] According to at least one embodiment of the present invention, there are provided a cryogenic energy recovery system and a ship capable of efficiently vaporizing two types of liquid fuels while recovering the cryogenic energy of the liquid fuels. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a schematic diagram of a vessel according to an embodiment; [Figure 2] 1 is a schematic diagram of a cold heat recovery facility according to an embodiment. [Figure 3] 1 is a schematic diagram of a cold heat recovery facility according to an embodiment. [Figure 4] 1 is a schematic diagram of a cold heat recovery facility according to an embodiment. [Figure 5] 1 is a schematic diagram of a cold heat recovery facility according to an embodiment. [Figure 6] 1 is a schematic diagram of a cold heat recovery facility according to an embodiment. [Figure 7] 1 is a schematic diagram of a cold heat recovery facility according to an embodiment. [Figure 8] FIG. 1 is a schematic diagram of a computer, which is an example of high-temperature equipment. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, several embodiments of the present invention will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of components described as embodiments or shown in the drawings are merely illustrative examples and are not intended to limit the scope of the present invention.

[0012] (Vessel configuration) Fig. 1 is a schematic diagram of a ship to which a cold energy recovery system according to some embodiments is applied. As shown in Fig. 1, the ship 1 includes a hull 2 (floating body), a cold energy recovery system 100 including a first fuel tank 10 and a second fuel tank 20 provided on the hull 2, and a prime mover 6 provided on the hull 2.

[0013] The hull 2 has a bow 2a shaped to reduce the resistance that the hull 2 receives from fluids such as seawater, and a stern 2b to which a rudder 3 for adjusting the direction of travel of the hull 2 can be attached.

[0014] The prime mover 6 may be configured to generate power to drive the propeller 4 as a propulsion device. The prime mover 6 may include an engine or a turbine such as a gas turbine, or may include an electric motor.

[0015] 1, the vessel 1 may be equipped with a fuel cell 8. An electric motor serving as the prime mover 6 may be driven by the power generated by the fuel cell 8.

[0016] The first fuel tank 10 is configured to store a first fuel in a liquid state. The second fuel tank 20 is configured to store a second fuel in a liquid state. Here, the liquefaction temperature (or boiling point) of the first fuel is lower than the liquefaction temperature (or boiling point) of the second fuel (i.e., the liquefaction temperature of the second fuel is higher than the liquefaction temperature of the first fuel). In other words, the temperature of the first fuel in a liquid state stored in the first fuel tank 10 is lower than the temperature of the second fuel in a liquid state stored in the second fuel tank 20.

[0017] In some embodiments, the first fuel is hydrogen (liquefaction temperature: approximately −253° C.) and the second fuel is natural gas (liquefaction temperature: approximately −163° C.). In this case, the first fuel tank 10 stores liquefied hydrogen (LH2) at approximately −253° C., and the second fuel tank 20 stores liquefied natural gas (LNG) at approximately −163° C.

[0018] 1 , the ship 1 is a ship that is propelled using a first fuel stored in a first fuel tank 10 and a second fuel stored in a second fuel tank 20 as fuel. As will be described in detail later, the cold energy recovery system 100 includes a first fuel line 12 for guiding the first fuel from the first fuel tank 10 to a supply destination, a first heat exchanger 36 provided in the first fuel line 12, a second fuel line 22 for guiding the second fuel from the second fuel tank 20 to a supply destination, and a third heat exchanger 42 provided in the second fuel line 22.

[0019] In the cold energy recovery system 100, the first fuel in a liquid state from the first fuel tank 10 is vaporized by heat exchange in the first heat exchanger 36. Also, the second fuel in a liquid state from the second fuel tank 20 is vaporized by heat exchange in the third heat exchanger 42. The vaporized first fuel and second fuel in a gaseous state are heated to an appropriate temperature by a heater or the like as necessary, and then supplied as fuel to the prime mover 6 (engine, gas turbine, etc.) or the fuel cell 8 via the first fuel line 12 and the second fuel line 22.

[0020] The cold energy recovery system according to the present invention is not limited to being installed on a ship, and may be installed on water facilities other than a ship, or may be installed on land.

[0021] (Configuration of cold heat recovery equipment) Hereinafter, a cold heat recovery system 100 according to several embodiments will be described. Each of Figures 2 to 7 is a schematic diagram of the cold heat recovery system 100 according to one embodiment.

[0022] As shown in FIGS. 2 to 7 , a cold energy recovery system 100 according to some embodiments includes a first fuel tank 10 for storing a first fuel in a liquid state and a second fuel tank 20 for storing a second fuel in a liquid state. As described above, the liquefaction temperature of the first fuel is lower than the liquefaction temperature of the second fuel. A first fuel line 12 for guiding the first fuel to a supply destination (e.g., the prime mover 6 or the fuel cell 8) is connected to the first fuel tank 10, and a pump 14 for pumping the first fuel is provided in the first fuel line 12. A second fuel line 22 for guiding the second fuel to a supply destination (e.g., the prime mover 6 or the fuel cell 8) is connected to the second fuel tank 20, and a pump 24 for pumping the second fuel is provided in the second fuel line 22.

[0023] The cold energy recovery equipment 100 shown in Figures 2 to 7 further includes a first circuit 32 configured to circulate a first medium, and a first expansion turbine 34, a first heat exchanger 36, a pump 38, a second heat exchanger 40, and a third heat exchanger 42, each of which is provided on the first circuit 32.

[0024] The first expansion turbine 34 is configured to expand the first medium in a gaseous state flowing through the first circuit 32. The first expansion turbine 34 expands the first medium in a gaseous state to recover turbine rotational power from the first medium.

[0025] In the illustrated exemplary embodiment, a generator 35 is connected to the first expansion turbine 34. The generator 35 is configured to be rotationally driven by the energy recovered by the first expansion turbine 34 to generate electricity.

[0026] The first heat exchanger 36 is provided on the first circuit 32 downstream of the first expansion turbine 34. The first heat exchanger 36 is configured to condense the first medium by exchanging heat between the first medium flowing through the first circuit 32 and the first fuel from the first fuel tank 10 flowing through the first fuel line 12. The first heat exchanger 36 is also configured to vaporize the first fuel in a liquid state through heat exchange with the first fuel. The first fuel from the first fuel tank 10 flows into the first heat exchanger 36 in a liquid state.

[0027] The pump is provided on the first circuit 32 downstream of the first heat exchanger and is configured to increase the pressure of the first medium condensed in the first heat exchanger .

[0028] The second heat exchanger 40 is provided on the first circuit 32 downstream of the pump 38. The second heat exchanger 40 is configured to exchange heat between the first medium flowing through the first circuit 32 and a heat medium (e.g., seawater) supplied to the second heat exchanger 40 via a heat medium line 41, thereby evaporating the first medium in a liquid state.

[0029] The third heat exchanger 42 is provided on the first circuit 32 downstream of the second heat exchanger 40 and upstream of the first expansion turbine 34. The third heat exchanger 42 is configured to exchange heat between the first medium flowing through the first circuit 32 and the second fuel from the second fuel tank 20 flowing through the second fuel line 22, thereby vaporizing the second fuel in a liquid state. The second fuel from the second fuel tank 20 flows into the third heat exchanger 42 in a liquid state.

[0030] The first heat exchanger 36, the pump 38, the second heat exchanger 40, and the first expansion turbine 34 provided on the first circuit 32 form a first thermodynamic cycle 30 that uses the first medium as a working medium and the first fuel in a liquid state in the first heat exchanger 36 as a low-temperature heat source.

[0031] The first medium may be a fluid with a relatively low freezing point that is unlikely to freeze even when heat exchange occurs with the first fuel in a liquid state at a relatively low temperature. When the first fuel is hydrogen, for example, nitrogen (N2) or argon (Ar) may be used as the first medium.

[0032] The first fuel line 12 may be provided with a heater 16 for heating the first fuel. The first fuel vaporized in the first heat exchanger 36 may be heated to an appropriate temperature by the heater 16 and then supplied to the prime mover 6 or the fuel cell 8 via the first fuel line 12. The second fuel line 22 may be provided with a heater 26 for heating the second fuel. The second fuel vaporized in the third heat exchanger 42 may be heated to an appropriate temperature by the heater 26 and then supplied to the prime mover 6 or the fuel cell 8 via the second fuel line 22.

[0033] The heater 16 may be configured to heat the first fuel by heat exchange with a heat medium (e.g., seawater) supplied via a heat medium line 17. The heater 26 may be configured to heat the second fuel by heat exchange with a heat medium (e.g., seawater) supplied via a heat medium line 27.

[0034] In the above-described embodiment, the second fuel supplied to the third heat exchanger 42 provided in the first circuit 32 between the second heat exchanger 40 and the first expansion turbine 34 has a higher liquefaction temperature than the first fuel. Therefore, in the first thermodynamic cycle 30, the first medium can exist as a gas at a relatively high temperature (for example, a temperature higher than the temperature required to vaporize the first fuel) at the outlet of the third heat exchanger 42, where the gaseous first medium is cooled by heat exchange with the second fuel. Therefore, a heat drop (or a temperature difference of the gaseous first medium) between the inlet and outlet of the first expansion turbine 34 can be ensured, and energy can be recovered in the first expansion turbine 34. In the above-described embodiment, the first fuel and the second fuel in a liquid state are vaporized by heat exchange with the first medium in the first heat exchanger 36 and the third heat exchanger 42 provided on the first circuit 32. In this manner, both the first fuel and the second fuel can be efficiently vaporized as liquid fuels using one thermodynamic cycle (the first thermodynamic cycle 30). Therefore, according to the above-described embodiment, it is possible to efficiently vaporize two types of liquid fuels while recovering the cryogenic energy of the liquid fuels.

[0035] 3 to 7, the cold energy recovery system 100 includes a fourth heat exchanger 44 that is provided on the first circuit 32 downstream of the third heat exchanger 42 and upstream of the first expansion turbine 34 and that heats the first medium. The fourth heat exchanger 44 may be configured to heat the first medium by heat exchange with a heat medium (e.g., seawater) flowing through a heat medium line 45.

[0036] According to the above-described embodiment, the fourth heat exchanger 44 for heating the first medium flowing on the upstream side of the first expansion turbine 34 is provided on the first circuit 32, so it is possible to increase the temperature of the first medium at the inlet of the first expansion turbine 34. This makes it possible to increase the heat drop between the inlet and outlet of the first expansion turbine 34, thereby enabling the output of the first expansion turbine 34 to be increased.

[0037] 4 and 5, the cold energy recovery system 100 includes a second circuit 52 configured to circulate a second medium, and a second expansion turbine 54 provided on the second circuit 52. The second expansion turbine 54 is configured to expand the gaseous first medium flowing through the second circuit, and forms part of a thermodynamic cycle (second thermodynamic cycle 50) together with the second circuit 52.

[0038] More specifically, the cold energy recovery system 100 includes a condenser 56 (heat exchanger) provided downstream of the second expansion turbine 54 on the second circuit 52, a pump 57 provided downstream of the condenser 56, and an evaporator 58 provided downstream of the pump 57 and upstream of the second expansion turbine 54. The condenser 56 is configured to condense the second medium in a gaseous state. The pump 57 is configured to increase the pressure of the second medium in a liquid state. The evaporator 58 includes an evaporator 58 for evaporating the second medium in a liquid state. The second thermodynamic cycle 50 is formed by these devices.

[0039] In the illustrated exemplary embodiment, a generator 55 is connected to the second expansion turbine 54. The generator 55 is configured to be rotationally driven by the energy recovered by the second expansion turbine 54 to generate electricity.

[0040] The condenser 56 is configured to exchange heat between the first medium flowing through the first circuit 32 and the second medium flowing through the second circuit 52. That is, in the condenser 56, the second medium is condensed by heat exchange with the first medium. Also, in the condenser 56, the first medium is heated by heat exchange with the second medium.

[0041] The evaporator 58 is configured to evaporate the second medium by heat exchange with a heat medium (such as seawater) flowing through a heat medium line 59.

[0042] The second medium can be a fluid having a higher freezing point than the first medium. When the first medium is nitrogen or argon, the second medium can be a fluid used as a working medium in a conventional cold energy recovery cycle on an LNG carrier or the like (e.g., an organic refrigerant such as R1234zee).

[0043] According to the above-described embodiment, the second circuit 52 and the second expansion turbine 54 form a second thermodynamic cycle 50 using the second medium as a working medium and utilizing the first medium, which has received cold energy from the first fuel in a liquid state, as a low-temperature heat source, and the second expansion turbine 54 is driven by the second medium in a gaseous state. Therefore, the cold energy of the first fuel in a liquid state can be further recovered. If a generator is connected to the first expansion turbine 34 and the second expansion turbine 54, the amount of power generation can be increased. In the above-described embodiment, a fluid with a relatively low freezing point can be used as the second medium flowing through the second circuit 52. This makes it possible to prevent the fluid from freezing in the heat exchanger (condenser 56) that exchanges heat between the first medium and the second medium. This makes it possible to prevent the heat exchanger from malfunctioning due to the freezing of the fluid.

[0044] In the exemplary embodiment shown in FIG. 4, the second heat exchanger 40 for evaporating the first medium functions as a condenser 56 for condensing the second medium.

[0045] In this embodiment, the first medium of the first thermodynamic cycle 30 and the second medium of the second thermodynamic cycle 50 are heat exchanged in the second heat exchanger 40 (condenser 56). Therefore, the first thermodynamic cycle 30, which uses the second medium as a high-temperature heat source in the second heat exchanger 40 (condenser 56), and the second thermodynamic cycle 50, which uses the first medium as a low-temperature heat source in the second heat exchanger 40 (condenser 56), can be efficiently driven, and the cold energy of the first fuel in a liquid state can be effectively recovered.

[0046] In the exemplary embodiment shown in FIG. 5, the fourth heat exchanger 44 for raising the temperature of the first medium in a gaseous state functions as a condenser 56 for condensing the second medium.

[0047] In the first thermodynamic cycle 30, the first medium that has received the cold energy of the second fuel in a liquid state in the third heat exchanger 42 flows into the fourth heat exchanger 44. In the above-described embodiment, the first medium of the first thermodynamic cycle 30 and the second medium of the second thermodynamic cycle 50 exchange heat in the fourth heat exchanger 44 (condenser 56). Therefore, the energy of the second fuel can also be recovered in the second thermodynamic cycle 50, which uses the first medium that has received the cold energy of the second fuel as a low-temperature heat source. Furthermore, the fourth heat exchanger 44 (condenser 56) can heat and increase the temperature of the first medium flowing upstream of the first expansion turbine 34 on the first circuit 32. Therefore, the heat drop between the inlet and outlet of the first expansion turbine 34 can be increased, thereby increasing the output of the first expansion turbine 34.

[0048] In some embodiments, an inert substance (such as nitrogen or argon) as the first medium is configured to circulate through the first circuit 32. Then, as shown in, for example, FIGS. 6 and 7 , at least a portion of the first medium (the first medium in a gaseous state at a relatively high pressure) flowing on the first circuit 32 downstream of the second heat exchanger 40 and upstream of the first expansion turbine 34 is configured to be supplied to an inert gas utilization device 60.

[0049] The inert gas utilization equipment 60 may be equipment other than the equipment provided on the first circuit 32 and forming the first thermodynamic cycle 30 (such as the first expansion turbine 34 and heat exchangers such as the first heat exchanger 36).

[0050] In the exemplary embodiment shown in FIG. 6, the piping forming the first circuit 32 is connected to an inert gas utilization device 60, and the inert gas utilization device 60 forms part of the circulation path (first circuit 32) of the first medium.

[0051] 7, the cold energy recovery facility 100 includes a supply line 62 branching off from the first circuit 32 upstream of the first expansion turbine 34 to supply the first medium to the inert gas utilization equipment 60, and a return line 64 joining the first circuit 32 downstream of the first expansion turbine 34 to return the first medium from the inert gas utilization equipment 60 to the first circuit 32. As shown in FIG. 7, the supply line 62 may be provided with a valve 63 for adjusting the amount of the first medium flowing through the supply line 62.

[0052] In the above-described embodiment, an inert substance is used as the first medium, and at least a portion of the first medium (inert gas) in a relatively high-pressure gas state in the first circuit 32 is supplied to the inert gas-using device 60. In this way, the first medium, which is an inert substance, can be effectively used for a purpose other than that of the working medium.

[0053] The inert gas utilization device 60 described above may be, for example, a gas transport pipe for transporting a flammable gas. The gas transport pipe may have a double-pipe structure including an inner piping for flowing the flammable gas and an outer piping provided on the outer periphery of the inner piping. At least a portion of the first medium flowing downstream of the second heat exchanger 40 and upstream of the first expansion turbine 34 on the first circuit 32 may be supplied to the outer periphery piping of the gas transport pipe. The gas transport pipe described above may be a pipe constituting the first fuel line 12 or the second fuel line 22.

[0054] According to the above-described embodiment, a first medium gas (inert gas), which is an inert substance, is supplied to the outer periphery piping of the gas transport pipe having a double-pipe structure. Therefore, even if a flammable gas leaks from the inner periphery piping, the flammable gas is transported by the inert gas, thereby accelerating detection by the gas detector. In this way, the first working medium can be effectively utilized to quickly detect gas leakage. The gas detector may include a sensor configured to detect the flammable gas in the outer periphery piping.

[0055] In some embodiments, at least one of the heat exchangers provided on the first circuit 32 may be configured to exchange heat between the first medium and the cooling fluid that has cooled the high-temperature equipment.

[0056] 2, 3, and 5 to 7, the second heat exchanger 40 may be configured to exchange heat between the cooling fluid that has cooled the high-temperature equipment and the first medium. That is, the heat medium supplied to the second heat exchanger 40 via the heat medium line 41 may include the cooling fluid (cooling water or cooling oil) that has cooled the high-temperature equipment.

[0057] 3, 4, 6, and 7, the fourth heat exchanger 44 may be configured to exchange heat between the cooling fluid that has cooled the high-temperature equipment and the first medium. That is, the heat medium supplied to the fourth heat exchanger 44 via the heat medium line 45 may include the cooling fluid (cooling water or cooling oil) that has cooled the high-temperature equipment.

[0058] In the above-described embodiment, the cooling fluid that has cooled the high-temperature equipment is used as a heat source for heating the first medium, and thus the exhaust heat of the high-temperature equipment can be effectively utilized to efficiently vaporize the first and second fuels in a liquid state while recovering the cold energy of the liquid fuel.

[0059] The high-temperature equipment may include a computer. Fig. 8 is a schematic diagram of a computer, which is an example of high-temperature equipment. The computer 92 shown in Fig. 8 is an immersion server configured to be cooled by being immersed in liquid refrigerant oil 101.

[0060] The calculator 92 is installed in an immersion tank 94 while immersed in liquid refrigerant oil 101. A condenser 98 is provided above the liquid refrigerant oil 101 in the immersion tank 94. The immersion tank 94 has a sealed structure, and liquid refrigerant oil 101 and gaseous refrigerant oil 102 coexist in the immersion tank 94. A cooling fluid (cooling water, cooling oil, or the like) is supplied to the condenser 98 via a cooling fluid line 96. A pump 97 is provided in the cooling fluid line 96.

[0061] In the immersion tank 94, the liquid refrigerant oil 101 vaporizes due to heat from the computer 92. The gaseous refrigerant oil 102 is cooled and liquefied in the condenser 98. This repeated vaporization and liquefaction of the refrigerant oil transfers the heat from the computer 92 to the cooling fluid via the refrigerant oil in the immersion tank 94 and the condenser 98. In this way, the computer 92 is cooled by the cooling fluid.

[0062] The cooling fluid discharged from the condenser 98 in the cooling fluid line 96 may be supplied to the second heat exchanger 40 or the fourth heat exchanger 44 via the heat medium line 41 or the heat medium line 45. Furthermore, the cooling fluid discharged from the second heat exchanger 40 or the fourth heat exchanger 44 after heat exchange in these heat exchangers may be supplied again to the condenser 98 of the immersion tank 94 via the cooling fluid line 96.

[0063] The computer serving as the high-temperature equipment described above is not limited to an immersion server. In some embodiments, the computer may be any other known liquid-cooled computer, such as a water-cooled computer in which the processor is cooled with water.

[0064] According to the above-described embodiment, the cooling fluid that has cooled the computer 92 is used as a heat source for heating the first medium. Therefore, by effectively utilizing the exhaust heat of the high-temperature equipment, it is possible to efficiently vaporize two types of liquid fuel (the first fuel and the second fuel) and recover the cold energy of the liquid fuel.

[0065] The contents described in each of the above embodiments can be understood, for example, as follows.

[0066] (1) At least one embodiment of the cold energy recovery system (100) of the present invention comprises: a first fuel tank (10) for storing a first fuel in a liquid state; a second fuel tank (20) for storing a second fuel in a liquid state having a liquefaction temperature higher than that of the first fuel; a first circuit (32) configured to circulate a first medium; a first expansion turbine (34) provided on the first circuit for expanding the first medium in a gaseous state; a first heat exchanger (36) provided on the first circuit downstream of the first expansion turbine for condensing the first medium; a pump (38) provided on the first circuit downstream of the first heat exchanger for increasing the pressure of the first medium; a second heat exchanger (40) provided on the first circuit downstream of the pump for evaporating the first medium; a third heat exchanger (42) provided on the first circuit downstream of the second heat exchanger and upstream of the first expansion turbine, the first heat exchanger is configured to vaporize the first fuel by heat exchange between the first fuel in a liquid state from the first fuel tank and the first medium, The third heat exchanger is configured to vaporize the second fuel by heat exchange between the second fuel in a liquid state from the second fuel tank and the first medium.

[0067] In the above configuration (1), the first heat exchanger, pump, second heat exchanger, and first expansion turbine provided on the first circuit constitute a thermodynamic cycle (hereinafter referred to as the first thermodynamic cycle) that uses the first medium as a working medium and the first fuel in a liquid state with a relatively low liquefaction temperature as a low-temperature heat source. Here, the second fuel supplied to the third heat exchanger provided between the second heat exchanger and the first expansion turbine in the first circuit has a higher liquefaction temperature than the first fuel. Therefore, in the above-mentioned thermodynamic cycle, the first medium can exist as a gas at a relatively high temperature (for example, a temperature higher than the temperature required to vaporize the first fuel) at the outlet of the third heat exchanger, where the gaseous first medium is cooled by heat exchange with the second fuel. Therefore, a heat drop (or a temperature difference of the gaseous first medium) between the inlet and outlet of the first expansion turbine can be secured, and energy can be recovered in the first expansion turbine. In the configuration (1) above, the first fuel and the second fuel in a liquid state are vaporized by heat exchange with the first medium in the first heat exchanger and the third heat exchanger provided on the first circuit, respectively. In this way, both the first fuel and the second fuel can be efficiently vaporized using one thermodynamic cycle. Therefore, according to the above configuration (1), it is possible to efficiently vaporize two types of liquid fuels while recovering the cold energy of the liquid fuels.

[0068] (2) In some embodiments, in the configuration of (1), The cold heat recovery equipment includes: The compressor further comprises a fourth heat exchanger (44) that is provided on the first circuit downstream of the third heat exchanger and upstream of the second expansion turbine and that heats the first medium.

[0069] According to the configuration (2) above, a heat exchanger for heating the first medium flowing upstream of the first expansion turbine is provided on the first circuit, so the temperature of the first medium at the inlet of the first expansion turbine can be increased, thereby increasing the heat drop between the inlet and outlet of the first expansion turbine and thereby increasing the output of the first expansion turbine.

[0070] (3) In some embodiments, in the configuration of (1) or (2), The cold heat recovery equipment includes: a second circuit (52) configured to circulate a second medium; a second expansion turbine (54) provided on the second circuit to form part of a thermodynamic cycle together with the second circuit for expanding the second medium in a gaseous state; and a heat exchanger (for example, the second heat exchanger 40 or the fourth heat exchanger 44) provided on the first circuit and configured to heat the first medium by heat exchange with the second medium.

[0071] According to the above configuration (3), the second circuit and the second expansion turbine form a thermodynamic cycle (hereinafter referred to as the second thermodynamic cycle) that uses the second medium as a working medium and that utilizes the first medium, which has received cold energy from the first fuel in a liquid state, as a low-temperature heat source, and the second expansion turbine is driven by the second medium in a gaseous state, thereby making it possible to further recover cold energy from the first fuel in a liquid state. In the configuration (3), a fluid with a relatively low freezing point can be used as the second medium flowing through the second circuit, thereby preventing the fluid from freezing in the heat exchanger that exchanges heat between the first medium and the second medium.

[0072] (4) In some embodiments, in the configuration of (3), The heat exchanger includes the second heat exchanger (40).

[0073] In the above configuration (4), the first medium of the first thermodynamic cycle and the second medium of the second thermodynamic cycle are heat exchanged in the second heat exchanger (heat exchanger). Therefore, the first thermodynamic cycle, which uses the second medium as a high-temperature heat source in the second heat exchanger, and the second thermodynamic cycle, which uses the first medium as a low-temperature heat source in the second heat exchanger, can be efficiently driven, and the cold energy of the first fuel in a liquid state can be effectively recovered.

[0074] (5) In some embodiments, in the configuration of (3), The cold heat recovery equipment includes: a fourth heat exchanger (44) provided on the first circuit downstream of the third heat exchanger and upstream of the expansion turbine for heating the first medium; The heat exchanger includes the fourth heat exchanger.

[0075] The first medium, which has received the cold energy of the second fuel in a liquid state in the third heat exchanger, flows into the fourth heat exchanger. In this regard, in the configuration (5) above, the first medium of the first thermodynamic cycle and the second medium of the second thermodynamic cycle exchange heat in the fourth heat exchanger (heat exchanger). Therefore, the energy of the second fuel can also be recovered in the second thermodynamic cycle, which uses the first medium, which has received the cold energy of the second fuel, as a low-temperature heat source. Furthermore, the fourth heat exchanger can heat and increase the temperature of the first medium flowing upstream of the first expansion turbine on the first circuit. Therefore, the heat drop between the inlet and outlet of the first expansion turbine can be increased, thereby increasing the output of the first expansion turbine.

[0076] (6) In some embodiments, in any of the configurations (1) to (5) above, The cold heat recovery equipment includes: A heat exchanger (for example, the second heat exchanger 40 or the fourth heat exchanger 44) is provided on the first circuit for heating the first medium by heat exchange with a cooling fluid that has cooled a high-temperature device.

[0077] In the configuration (6) above, the cooling fluid that has cooled the high-temperature equipment is used as a heat source for heating the first medium, and thus, by effectively utilizing the exhaust heat of the high-temperature equipment, it is possible to efficiently vaporize two types of liquid fuels and recover the cold energy of the liquid fuels, as described in (1) above.

[0078] (7) In some embodiments, in the configuration of (6), The high-temperature equipment includes a computer (92).

[0079] According to the above configuration (7), the cooling fluid that has cooled the computer is used as a heat source for heating the first medium, and thus the waste heat of the high-temperature equipment can be effectively utilized to efficiently vaporize the two types of liquid fuels and recover the cold energy of the liquid fuels.

[0080] (8) In some embodiments, in any of the configurations (1) to (7) above, The cold heat recovery equipment includes: A first generator (35) is configured to be driven by the first expansion turbine.

[0081] According to the configuration (8) above, the first generator can be driven by the first expansion turbine forming the first thermodynamic cycle, and thus the two types of liquid fuels can be efficiently vaporized while driving the first generator using the cold energy of the first fuel in a liquid state.

[0082] (9) In some embodiments, in any of the configurations (1) to (8) above, An inert substance as the first medium is configured to circulate through the first circuit; At least a portion of the first medium flowing on the first circuit downstream of the second heat exchanger and upstream of the first expansion turbine is supplied to an inert gas utilization device (60).

[0083] According to the above configuration (9), an inert substance is used as the first medium, and at least a portion of the first medium (inert gas) in a relatively high-pressure gas state in the first circuit is supplied to the inert gas-using device. In this way, the first medium, which is an inert substance, can be effectively used for a purpose other than the working medium.

[0084] (10) In some embodiments, in the configuration of (9), The cold heat recovery equipment includes: The inert gas utilization equipment includes a gas transport pipe for transporting a flammable gas, the gas transport pipe has a double pipe structure including an inner circumferential side pipe for flowing the flammable gas and an outer circumferential side pipe provided on the outer circumferential side of the inner circumferential side pipe, The outer periphery side pipe is configured to supply the at least part of the first medium.

[0085] According to the configuration (10) above, since the first medium gas (inert gas), which is an inert substance, is supplied to the outer piping of the gas transport pipe having a double pipe structure, even if flammable gas leaks from the inner piping, the flammable gas is transported by the inert gas, and detection by the gas detector can be accelerated. In this way, the first medium can be effectively used to quickly detect gas leakage.

[0086] (11) A watercraft (1) according to at least one embodiment of the present invention includes: Hull (2) and a cold energy recovery system (100) according to any one of (1) to (10) above, which is provided on the ship body; a prime mover (6) or a fuel cell (7) provided in the hull and using the first fuel vaporized in the first heat exchanger and the second fuel vaporized in the third heat exchanger as fuel; Equipped with.

[0087] According to the configuration (11) above, the first heat exchanger, the pump, the second heat exchanger, and the first expansion turbine provided on the first circuit constitute a thermodynamic cycle (hereinafter referred to as the first thermodynamic cycle) that uses the first medium as a working medium and the first fuel in a liquid state with a relatively low liquefaction temperature as a low-temperature heat source. Here, the second fuel supplied to the third heat exchanger provided between the second heat exchanger and the first expansion turbine in the first circuit has a higher liquefaction temperature than the first fuel. Therefore, in the above-described thermodynamic cycle, the first medium can maintain a gaseous state even after being condensed by heat exchange with the first fuel in a liquid state, pressurized by the pump, vaporized in the second heat exchanger, and then cooled by heat exchange with the second fuel in a liquid state in the third heat exchanger. Therefore, the first medium in a gaseous state flows into the first expansion turbine, allowing energy to be recovered by the first expansion turbine. In the configuration (11) above, the first fuel and the second fuel in a liquid state are vaporized by heat exchange with the first medium in the first heat exchanger and the third heat exchanger provided on the first circuit, respectively. In this way, both the first fuel and the second fuel can be efficiently vaporized using one thermodynamic cycle. Therefore, according to the above configuration (11), it is possible to efficiently vaporize two types of liquid fuels while recovering the cold energy of the liquid fuels.

[0088] The above describes an embodiment of the present invention, but the present invention is not limited to the above-described embodiment, and also includes forms in which the above-described embodiment is modified, or forms in which these forms are appropriately combined.

[0089] In this specification, expressions expressing relative or absolute arrangement such as "in a certain direction," "along a certain direction," "parallel," "orthogonal," "center," "concentric," or "coaxial" not only express such an arrangement strictly, but also express a state in which there is a relative displacement with a tolerance or an angle or distance to the extent that the same function is obtained. For example, expressions such as "identical," "equal," and "homogeneous" that indicate that something is in an equal state not only indicate a state of strict equality, but also indicate a state in which there is a tolerance or a difference to the extent that the same function is obtained. Furthermore, in this specification, expressions representing shapes such as a rectangular shape or a cylindrical shape not only represent rectangular shapes or cylindrical shapes in the strict geometric sense, but also represent shapes including uneven portions, chamfered portions, etc., to the extent that the same effect can be obtained. Furthermore, in this specification, the expressions "comprise," "include," or "have" a component are not exclusive expressions that exclude the presence of other components. [Explanation of symbols]

[0090] 1 ship 2. Hull 2a bow 2b stern 3 Rudder 4 propellers 6. Prime Mover 8 fuel cell 10. No. 1 fuel tank 12 No. 1 fuel line 14 Pump 16 Heater 17 Heat Transfer Medium Line 20 Second fuel tank 22 Second fuel line 24 Pump 26 Heater 27 Heat Transfer Medium Line 30 First Thermodynamic Cycle 32 1st circuit 34 First expansion turbine 35 Generator 36 1st heat exchanger 38 Pump 40 Second heat exchanger 41 Heat Transfer Medium Line 42 Third heat exchanger 44 4th heat exchanger 45 Heat Transfer Medium Line 50 Second Thermodynamic Cycle 52 2nd circuit 54 Second expansion turbine 55 Generator 56 Condenser 57 Pump 58 Evaporator 59 Heat Transfer Medium Line 60 Inert gas utilization equipment 62 Supply Line 63 Valve 64 Return Line 92 Calculator 94 Immersion tank 96 Cooling fluid line 97 Pump 98 Condenser 100 Cold heat recovery equipment 101 Refrigerant oil in liquid state 102 Refrigerant oil in gaseous state

Claims

1. a first fuel tank for storing the first fuel in a liquid state; a second fuel tank for storing a second fuel in a liquid state having a liquefaction temperature higher than that of the first fuel; a first circuit configured to circulate a first medium; a first expansion turbine provided on the first circuit for expanding the first medium in a gaseous state; a first heat exchanger provided on the first circuit downstream of the first expansion turbine for condensing the first medium; a pump provided on the first circuit downstream of the first heat exchanger for increasing the pressure of the first medium; a second heat exchanger provided on the first circuit downstream of the pump for evaporating the first medium; a third heat exchanger provided on the first circuit downstream of the second heat exchanger and upstream of the first expansion turbine, the first heat exchanger is configured to vaporize the first fuel by heat exchange between the first fuel in a liquid state from the first fuel tank and the first medium, The third heat exchanger is configured to vaporize the second fuel by heat exchange between the second fuel in a liquid state from the second fuel tank and the first medium. Cold and heat recovery equipment.

2. a fourth heat exchanger provided on the first circuit downstream of the third heat exchanger and upstream of the first expansion turbine for heating the first medium; The cold heat recovery facility according to claim 1 .

3. a second circuit configured to circulate a second medium; a second expansion turbine provided on the second circuit to form part of a thermodynamic cycle together with the second circuit for expanding the second medium in a gaseous state; a heat exchanger provided on the first circuit and configured to heat the first medium by heat exchange with the second medium. The cold heat recovery facility according to claim 1 or 2.

4. The heat exchanger includes the second heat exchanger. The cold heat recovery facility according to claim 3.

5. a fourth heat exchanger provided on the first circuit downstream of the third heat exchanger and upstream of the first expansion turbine for heating the first medium; The heat exchanger includes the fourth heat exchanger. The cold heat recovery facility according to claim 3.

6. a heat exchanger provided on the first circuit for heating the first medium by heat exchange with a cooling fluid that has cooled a high-temperature device; The cold heat recovery facility according to any one of claims 1 to 5.

7. The high-temperature equipment includes a computer. The cold heat recovery facility according to claim 6.

8. a first generator configured to be driven by the first expansion turbine; The cold heat recovery facility according to any one of claims 1 to 7.

9. An inert substance as the first medium is configured to circulate through the first circuit; At least a portion of the first medium flowing on the first circuit downstream of the second heat exchanger and upstream of the first expansion turbine is supplied to an inert gas utilization device. The cold heat recovery facility according to any one of claims 1 to 8.

10. The inert gas utilization equipment includes a gas transport pipe for transporting a flammable gas, the gas transport pipe has a double pipe structure including an inner circumferential side pipe for flowing the flammable gas and an outer circumferential side pipe provided on the outer circumferential side of the inner circumferential side pipe, The outer periphery side pipe is configured to supply at least a portion of the first medium. The cold heat recovery facility according to claim 9.

11. The hull and The cold heat recovery equipment according to any one of claims 1 to 10, which is provided on the hull; a prime mover or a fuel cell provided in the hull, the prime mover or a fuel cell using the first fuel vaporized in the first heat exchanger and the second fuel vaporized in the third heat exchanger as fuel; A vessel equipped with:

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