Cold energy utilization method and cold energy utilization device

Abstract

To provide a cold energy utilization method and a cold energy utilization device capable of effectively utilizing cold energy of liquefied gas.SOLUTION: A cold energy utilization device 200 is used by connecting it to a plant 160 having a tank 110 that stores LNG (liquefied gas), and cools a target by heat exchange with the LNG before it is stored in the tank 110. The cold energy utilization device 200 also has a first heat exchange unit 300 that cools carbon dioxide N1 by heat exchange with the LNG, and a second heat exchange unit 400 that cools brine N2 by heat exchange with the carbon dioxide N1.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method and an apparatus for utilizing cold energy. [Background technology]

[0002] Patent Document 1 discloses a vaporizer that vaporizes LNG (liquefied natural gas). This vaporizer is an open rack vaporizer (ORV) and includes a plurality of heat exchange panels, a lower manifold that connects the heat exchange panels in parallel at their lower ends, and an upper manifold that connects the heat exchange panels in parallel at their upper ends. Each heat exchange panel includes a plurality of heat transfer tubes extending vertically, a lower header pipe that connects the heat transfer tubes at their lower ends, and an upper header pipe that connects the heat transfer tubes at their upper ends. The vaporizer also includes a trough that stores seawater to be supplied to the outer surface of each heat transfer tube, and seawater supply means that supplies seawater to the trough.

[0003] In such a vaporizer, LNG is introduced from the lower manifold into each heat transfer tube through a lower header tube. Meanwhile, seawater stored in the trough by a seawater supply means overflows from the trough and hangs down while wetting the outer surface of the heat transfer tube. The LNG introduced into the heat transfer tube is heated and vaporized by the seawater flowing outside the heat transfer tube, becoming NG (natural gas), which rises inside the heat transfer tube. Then, this NG is led to the upper manifold through an upper header tube. In this way, the vaporizer of Patent Document 1 generates NG by heating and vaporizing LNG through heat exchange with seawater. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2013-148253 A Summary of the Invention [Problem to be solved by the invention]

[0005] In a typical plant, a tank for temporarily storing LNG is arranged upstream of the vaporizer of Patent Document 1, and the LNG discharged from this tank is vaporized by the vaporizer. Therefore, in such a plant, it is not possible to utilize the cold energy of the LNG stored in the tank, i.e., the LNG before it is vaporized by the vaporizer.

[0006] An object of the present invention is to provide a method and an apparatus for utilizing cold energy that can effectively utilize the cold energy of liquefied gas before it is vaporized. [Means for solving the problem]

[0007] Such an object can be achieved by the present invention described below.

[0008] (1) Used in connection with a plant having a tank for storing liquefied gas; A method for utilizing cold energy, comprising: cooling an object by heat exchange with the liquefied gas before it is stored in the tank.

[0009] (2) The plant has a receiving pipe that connects a carrier that transports the liquefied gas to the tank and guides the liquefied gas from the carrier to the tank, The method for utilizing cold energy according to (1) above, wherein the liquefied gas is introduced from the receiving pipe.

[0010] (3) a first heat exchange step of cooling a primary refrigerant by heat exchange with the liquefied gas; The method for utilizing cold energy according to (1) above, further comprising a second heat exchange step of cooling a secondary refrigerant by heat exchange with the primary refrigerant.

[0011] (4) The method for utilizing cold energy according to the above (3), wherein the liquefied gas used in the first heat exchange step is returned to the plant in a liquid state.

[0012] (5) The first heat exchange step includes a primary refrigerant cooling step of cooling the primary refrigerant by heat exchange with the liquefied gas; The method for utilizing cold energy described in (3) above, further comprising a condensing step of condensing the liquefied gas that has been at least partially gasified by the primary refrigerant cooling step.

[0013] (6) The method for utilizing cold energy according to (3) above, wherein the first heat exchange step further includes a depressurization step of depressurizing the liquefied gas prior to the primary refrigerant cooling step.

[0014] (7) A method for utilizing cold energy as described in (5) above, in which the condensation step condenses the liquefied gas that has undergone the primary refrigerant cooling step by heat exchange with the liquefied gas that has not undergone the primary refrigerant cooling step.

[0015] (8) The method for utilizing cold energy according to (3) above, further comprising an object cooling step of cooling the object using the secondary refrigerant cooled in the second heat exchange step.

[0016] (9) The method for utilizing cold energy described in (8) above, further comprising a storage step of storing the object cooled in the object cooling step in a cooled state using the secondary refrigerant cooled in the second heat exchange step.

[0017] (10) The method for utilizing cold energy according to the above (8), wherein in the second heat exchange step, a part of the secondary refrigerant is frozen to form a slurry.

[0018] (11) The object is a heat storage material, In the object cooling step, the unfrozen cold storage material is frozen, The method for utilizing cold energy according to (9) above, wherein in the storing step, the cold storage material is stored in a frozen state.

[0019] (12) The method for utilizing cold energy according to the above (1), wherein the liquefied gas is liquefied natural gas or liquefied petroleum gas.

[0020] (13) Used in connection with a plant having a tank for storing liquefied gas, A cold energy utilization device, characterized in that an object is cooled by heat exchange with the liquefied gas before it is stored in the tank. Effect of the Invention

[0021] According to the cold energy utilization method and cold energy utilization device of the present invention, it is possible to cool various objects using the cold energy of liquefied gas before vaporization that has not been used before. Therefore, the cold energy of the liquefied gas can be effectively utilized without being wasted. Furthermore, by effectively utilizing the cold energy that has not been used before, the consumption of other energy sources can be reduced, and the environmental load can be reduced accordingly. [Brief description of the drawings]

[0022] [Figure 1] 1 is an overall configuration diagram of a cold energy utilization device according to a first embodiment. [Diagram 2] FIG. 4 shows a second heat exchange unit. [Diagram 3] FIG. [Figure 4] FIG. [Diagram 5] FIG. [Figure 6] FIG. 13 is a diagram showing an example of a method for using a cold storage material. [Figure 7] FIG. 13 is a diagram showing an example of a method for using a cold storage material. [Figure 8] FIG. 11 is an overall configuration diagram of a cold energy utilization device according to a second embodiment. [Figure 9] FIG. 11 is a cross-sectional view showing a second heat exchanger according to a third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a method and an apparatus for utilizing cold energy according to the present invention will be described in detail with reference to the embodiments shown in the accompanying drawings.

[0024] The liquefied gas used in the cold energy utilization method and cold energy utilization device of the present invention is not particularly limited, but is typically LNG (liquefied natural gas) or LPG (liquefied petroleum gas). These are particularly consumed in large quantities among liquefied gases, and therefore the cold energy that is wasted is large. This results in a more beneficial cold energy utilization method and cold energy utilization device. However, the liquefied gas may be anything other than LNG and LPG, such as ammonia gas or hydrogen gas. In the following embodiments, for convenience of explanation, an example in which LNG is used as the liquefied gas will be described as a representative example, but other liquefied gases can be similarly applied.

[0025] First Embodiment First, we will briefly explain how NG (natural gas) is supplied in Japan. In Japan, most of the NG is imported. Also, since there are no pipelines between Japan and the countries of origin of NG, it is imported by sea transport. In order to increase the efficiency of transportation, the NG is converted into LNG (liquefied natural gas) at about -162°C in a liquefaction plant installed in the natural gas field, and then transported to the receiving terminal 100 using an LNG tanker T (mobile body).

[0026] As shown in Fig. 1, the receiving terminal 100 is mainly provided with a tank 110 for temporarily storing LNG transported by an LNG tanker T, a receiving pipe 170 for guiding LNG from the LNG tanker T to the tank 110, a vaporizer 120 for vaporizing the LNG stored in the tank 110 to generate a required amount of NG, a pipeline 130 for connecting the tank 110 and the vaporizer 120, a pump 140 disposed in the pipeline 130 for sending the LNG in the tank 110 to the vaporizer 120, and an odorizer 150 for adding an odor to the NG generated by the vaporizer 120. Although not shown, the NG odorized by the odorizer 150 is sent through gas pipes to gas holders installed in various places such as urban areas and stored therein, and is further sent from the gas holders to each contracted party through gas pipes.

[0027] The illustrated receiving terminal 100 has a pier that extends from land onto the ocean and can accommodate large LNG tankers, and a receiving pipe 170 extends to the tip of the pier. By connecting the receiving pipe 170 to an LNG tanker T that is docked at the pier, the LNG tanker T and the tank 110 are connected by the receiving pipe 170, and LNG is guided from the LNG tanker T to the tank 110 through the receiving pipe 170.

[0028] As shown in Fig. 1, the cold energy utilization device 200 is used by being connected to the plant 160. In particular, the cold energy utilization device 200 is connected midway through the receiving pipe 170. The cold energy utilization device 200 has a first heat exchange unit 300 that cools a primary refrigerant by heat exchange with LNG introduced from the receiving pipe 170, a second heat exchange unit 400 that cools a secondary refrigerant by heat exchange with the primary refrigerant, a cooling device 500 that cools an object by heat exchange with the secondary refrigerant, and a storage device 600 that maintains the cooled state of the object cooled by the cooling device 500 using the secondary refrigerant.

[0029] [First heat exchange unit] First, a description will be given of the first heat exchange unit 300. The first heat exchange unit 300 mainly includes a first heat exchanger 310 that performs heat exchange between the LNG introduced from the plant 160 and HFC (hydrofluorocarbon) that is a primary refrigerant, and a condenser 320 that condenses the LNG vaporized in the first heat exchanger 310.

[0030] The first heat exchanger 310 has an outer pipe 311 and an inner pipe 312 arranged to penetrate the outer pipe 311. Then, HFC is introduced into the outer pipe 311, and LNG is introduced into the inner pipe 312, whereby heat exchange occurs and the HFC is condensed.

[0031] The condenser 320 has the same configuration as the above-mentioned first heat exchanger 310. That is, the condenser 320 has an outer pipe 321 and an inner pipe 322 arranged to penetrate the outer pipe 321. Then, gaseous LNG that has passed through the first heat exchanger 310 is introduced into the outer pipe 321, and liquid LNG that has not passed through the first heat exchanger 310 is introduced into the inner pipe 322, whereby heat exchange is performed between them and the gaseous LNG that has passed through the first heat exchanger 310 is condensed.

[0032] As shown in FIG. 1, the receiving pipe 170 is connected to the inlet side of the inner pipe 312 by a pipe 331. A liquid feed pump 340 and an expansion valve 350 are provided in the pipe 331. The pipe 331 branches into a pipe 334 between the liquid feed pump 340 and the expansion valve 350, and the downstream side of the pipe 334 is connected to the inlet side of the inner pipe 322. That is, the pipe 334 bypasses the receiving pipe 170 and the condenser 320 without passing through the first heat exchanger 310. A flow rate control valve 360 ​​for controlling the amount of LNG supplied to the condenser 320 is provided in the pipe 334. The outlet side of the inner pipe 312 is connected to the inlet side of the outer pipe 321 by a pipe 332. The outlet side of the outer pipe 321 and the outlet side of the inner pipe 322 are joined in the middle by a pipe 333 and then connected to the receiving pipe 170.

[0033] In the first heat exchange unit 300 having such a configuration, a first heat exchange step is performed. In the first heat exchange step, by operating the liquid delivery pump 340, at least a part of the LNG on the way to the tank 110 through the receiving pipe 170 branches into the pipe 331 and proceeds through the pipe 331. Then, a part of the LNG is depressurized by the expansion valve 350 and introduced into the inner pipe 312 of the first heat exchanger 310, and the remaining part is introduced into the inner pipe 322 of the condenser 320 through the pipe 334. At this time, the amount of LNG introduced into the inner pipe 322 is adjusted by the flow rate control valve 360. The LNG introduced into the inner pipe 312 absorbs heat from the gaseous HFC introduced into the outer pipe 311 while vaporizing in the inner pipe 312, and is discharged from the inner pipe 312 in an at least partially gasified state, in the present embodiment, in an entirely gasified state. By reducing the pressure of LNG using expansion valve 350 before it is introduced into inner pipe 312, LNG is more likely to vaporize in inner pipe 312, and cooling efficiency is improved. Meanwhile, HFC in outer pipe 311 loses heat to the LNG introduced into inner pipe 312, condenses and liquefies, and is then discharged from outer pipe 311. With such first heat exchanger 310, since an ultra-low temperature LNG of -162° is used, HFC can be efficiently condensed and liquefied. This step is the pressure reduction step and the primary refrigerant cooling step.

[0034] The gaseous LNG discharged from the inner pipe 312 is introduced into the outer pipe 321 of the condenser 320 through the pipe 332. The liquid LNG directly introduced into the inner pipe 322 from the tank 110 through the pipe 334 absorbs heat from the gaseous LNG introduced into the outer pipe 321, and is discharged from the inner pipe 322 in a liquid state. On the other hand, the gaseous LNG introduced into the outer pipe 321 absorbs heat from the liquid LNG introduced into the inner pipe 322, condenses and liquefies, and is then discharged from the outer pipe 321. The liquid LNG discharged from the inner pipe 322 and the liquid LNG discharged from the outer pipe 321 join together midway through the pipe 333, and then join the receiving pipe 170. With such a condenser 320, the gasified LNG can be easily returned to a liquid state. This step is the condensation step.

[0035] For ease of explanation, FIG. 1 shows (G) indicating a gaseous state and (L) indicating a liquid state.

[0036] According to the first heat exchange unit 300 having such a configuration, the LNG borrowed from the plant 160 can be returned to the plant 160 in substantially the entire amount and in liquid form. Therefore, the amount of LNG is not substantially decreased, and the amount of NG production is not reduced. Furthermore, only the cold energy of LNG can be extracted without substantially consuming LNG. Therefore, it is an excellent heat exchange unit with a low environmental impact. Moreover, since the first heat exchange unit 300 only connects the pipeline 331 for borrowing LNG from the plant 160 and the pipeline 333 for returning the borrowed LNG to the plant 160 to the receiving piping 170, the processing process of the plant 160 can be the same as before. Therefore, the first heat exchange unit 300 can be introduced to the plant 160 without requiring large-scale repairs or modifications to the existing plant 160. Therefore, the introduction cost of the cold energy utilization device 200 is extremely low. Furthermore, in the condenser 320, the heat of the gaseous LNG introduced into the outer tube 321 is absorbed by the liquid LNG introduced into the inner tube 322, so that the environmental load can be reduced.

[0037] The first heat exchange unit 300 has been described above. However, the configuration of the first heat exchange unit 300 is not particularly limited as long as it can cool the HFC, which is the primary refrigerant, using LNG. The configuration of the condenser 320 is also not particularly limited as long as it can condense the gasified LNG. The junction point between the pipeline 333 and the plant 160 is not particularly limited, and for example, when liquid LNG is returned to the plant 160 as in this embodiment, it may be the tank 110 or between the tank 110 and the vaporizer 120. For example, the condenser 320 may be omitted and the gaseous LNG may be returned to the plant 160. In this case, the junction point between the pipeline 333 and the plant 160 is not particularly limited, and for example, it may be the tank 110, between the tank 110 and the vaporizer 120, or between the vaporizer 120 and the odorizer 150.

[0038] [Second heat exchange unit 400] Next, the second heat exchange unit 400 will be described. As shown in FIG. 1, the second heat exchange unit 400 mainly includes a second heat exchanger 410 that freezes a part of the ethanol aqueous solution (written as "EtOH" in the figure) that is a secondary refrigerant by heat exchange with HFC that is a primary refrigerant to generate ice slurry I, and a storage tank 420 that stores the generated ice slurry I. The ice slurry I refers to sherbet-like ice in which fine ice (crystals) are mixed in the ethanol aqueous solution, and is also called slurry ice, ice slurry, slurry ice, etc. In addition, the ethanol concentration of the ethanol aqueous solution is not particularly limited, but when used for the application of this embodiment (freezing and storage of the cold storage material 800 described later), it is preferably 45% or more, and more preferably 50% or more. This makes the freezing point of the ethanol aqueous solution -35°C or less. Therefore, the ice slurry I becomes lower, and as described later, the cold storage material 800 can be frozen more quickly.

[0039] As shown in FIG. 2, the second heat exchanger 410 has an outer tube 411 and an inner tube 412 arranged coaxially inside the outer tube 411. The outer tube 411 and the inner tube 412 are installed upright, with their axes facing the vertical direction. In other words, the second heat exchanger 410 is a vertically placed double-tube evaporator. The outer tube 411 and the inner tube 412 each have an inlet provided on the lower end side and an outlet provided on the upper end side. The liquid HFC condensed in the first heat exchanger 310 is introduced into the outer tube 411, and the ethanol aqueous solution is introduced into the inner tube 412, whereby heat exchange between them is performed and the ethanol aqueous solution is cooled.

[0040] The storage tank 420 has an inlet for introducing the ethanol aqueous solution cooled by the second heat exchanger 410, and an outlet for discharging the ethanol aqueous solution in the tank toward the second heat exchanger 410. The storage tank 420 also has an agitator (not shown) for agitating the ice slurry I in the tank. By agitating the ice slurry I with the agitator, aggregation of the ice slurry I in the storage tank 420 can be suppressed.

[0041] The outlet side of the outer pipe 411 is connected to the inlet side of the outer pipe 311 by a pipe 441, and the outlet side of the outer pipe 311 is connected to the inlet side of the outer pipe 411 by a pipe 442. A liquid feed pump 450 and an expansion valve 460 are provided in the middle of the pipe 442. The outlet side of the inner pipe 412 is connected to the inlet side of the storage tank 420 by a pipe 443, and the outlet side of the storage tank 420 is connected to the inlet side of the inner pipe 412 by a pipe 444. A liquid feed pump 470 is provided in the middle of the pipe 444.

[0042] In the second heat exchange unit 400 configured as above, a second heat exchange step is performed. In the second heat exchange step, the HFC is circulated between the outer pipe 411 and the outer pipe 311 through the pipes 441 and 442 by the operation of the liquid pump 450. The liquid HFC condensed in the first heat exchanger 310 is depressurized by the expansion valve 460 and then introduced into the outer pipe 411. The HFC introduced into the outer pipe 411 absorbs heat from the ethanol aqueous solution flowing in the inner pipe 412 while vaporizing in the pipe, and is discharged from the outer pipe 411 in a gasified state at least partially, and in this embodiment, entirely. The gaseous HFC discharged from the outer pipe 411 is condensed and liquefied again by the first heat exchanger 310. By circulating the HFC in this manner, the ethanol aqueous solution can be continuously cooled in the second heat exchanger 410. By reducing the pressure of the HFC by the expansion valve 460 before it is introduced into the outer pipe 411, the HFC becomes more likely to vaporize in the outer pipe 411, and the cooling efficiency is improved.

[0043] Along with this circulation of HFC, liquid feed pump 470 is operated to circulate the ethanol aqueous solution between inner pipe 412 and storage tank 420 via pipelines 443, 444. This causes the ethanol aqueous solution to be continuously cooled in second heat exchanger 410, gradually generating fine ice in the ethanol aqueous solution, and producing ice slurry I. The produced ice slurry I is stored in storage tank 420. With this second heat exchange unit 400, ice slurry I can be produced efficiently.

[0044] Here, if ice grows on the inner wall of inner tube 412 during the production of ice slurry I, the circulation of the ethanol aqueous solution may slow down, which may reduce the efficiency of production of ice slurry I. Therefore, inner tube 412 may be provided with a rotating blade for scraping off ice adhering to the inner wall, or with a stirrer for stirring the ethanol aqueous solution flowing inside inner tube 412 to make it difficult for ice to adhere to the inner wall. As another effect, the rotating blade or stirrer generates convection in the ethanol aqueous solution flowing inside inner tube 412, improving the efficiency of heat exchange between the HFC and the ethanol aqueous solution.

[0045] Although the second heat exchange unit 400 has been described above, the configuration of the second heat exchange unit 400 is not particularly limited as long as it is capable of cooling the secondary refrigerant using the primary refrigerant.

[0046] The primary refrigerant is not limited to HFC, and may be any refrigerant that can be cooled by LNG (liquefied gas) and can cool the secondary refrigerant. For example, natural refrigerants (gases) such as HCFC (hydrochlorofluorocarbon), HFO (hydrofluoroolefin), propane, propylene, butane, isobutane, hexafluoropropane, heptafluoropropane, ammonia, and carbon dioxide (carbon dioxide gas) may be used. For example, the primary refrigerant may be changed as appropriate depending on the type of liquefied gas and secondary refrigerant used in the cold energy utilization device 200.

[0047] The secondary refrigerant is not limited to an ethanol aqueous solution, and may be any refrigerant that can be cooled by the primary refrigerant and can cool the target object. For example, various alcohols such as ethylene glycol and propylene glycol or their aqueous solutions, sugar water, sodium chloride aqueous solution (salt water), calcium chloride aqueous solution, etc. may be used. For example, the secondary refrigerant can be changed as appropriate depending on the type of primary refrigerant and target object used in the cold energy utilization device 200.

[0048] [Cooling device 500] The cooling device 500 freezes the cold storage material 800, which is an object, by heat exchange with the ethanol aqueous solution. The cold storage material 800 is a container in which a cold pack is accommodated, and the container may be a soft type or a hard type. The cold storage material 800 is also called a cold insulation material. The difference between a cold storage material and a cold insulation material is not clear, but it is said that a cold storage material is one whose cold storage component is mostly water and freezes at a few degrees below freezing, and a cold storage material is one whose cold storage component is made of chemicals and freezes at 10 degrees below freezing.

[0049] As shown in FIG. 3, the cooling device 500 has a cooling tank 510 in which ice slurry I is stored. The unfrozen cold storage material 800 is immersed in the ice slurry I in the cooling tank 510 to cool and freeze the cold storage material 800. The ice slurry I (partially frozen secondary refrigerant) maintains the temperature of the ice slurry I near the freezing point of the ethanol aqueous solution until the ice components melt due to the action of latent heat. Since the heat of fusion required to turn a solid into a liquid is higher than the specific heat of the liquid, the inside of the cooling tank 510 can be maintained at a low temperature for a longer period of time, and the cold storage material 800 can be efficiently frozen. This step is the object cooling step.

[0050] The cooling tank 510 is connected to the storage tank 420 by pipes 521 and 522, and the ice slurry I in the storage tank 420 circulates between the cooling tank 510 and the ice slurry I. Specifically, the ethanol aqueous solution melted by heat exchange with the cold storage material 800 is returned to the storage tank 420 via pipe 521, and fresh ice slurry I in the storage tank 420 is supplied to the cooling tank 510 via pipe 522, so that the ice slurry I in the cooling tank 510 is maintained at a predetermined amount or more. Therefore, the ice slurry I is not depleted from the cooling tank 510, and the unfrozen cold storage material 800 can be continuously and efficiently frozen.

[0051] The cooling device 500 is provided with shelves 530 that can be raised and lowered above the cooling tank 510. The unfrozen cold storage materials 800 are arranged on the shelves 530, and each shelf 530 is immersed in the ice slurry I as shown in Fig. 4, so that the multiple cold storage materials 800 in the shelves 530 can be frozen at once. This makes the freezing operation easy. Note that the operation of arranging the unfrozen cold storage materials 800 on the shelves 530, the operation of immersing the shelves 530 in the ice slurry I, and the operation of collecting the frozen cold storage materials 800 from the shelves 530 may be performed by an operator or automatically by a machine.

[0052] Although the cooling device 500 has been described above, the configuration of the cooling device 500 is not particularly limited as long as it can freeze the cold storage material 800 using the ice slurry I. For example, the storage tank 420 and the cooling tank 510 may not be connected, and the ice slurry I in the storage tank 420 may be transported to the cooling tank 510 by an operator.

[0053] Furthermore, the object to be cooled by the ice slurry I is not limited to the cold storage material 800, and may be anything that requires cooling, such as liquids such as water and salt water, foods such as raw meat, seafood, vegetables, and fruits, organs, medicines, etc. Also, the object does not need to be frozen.

[0054] [Storage device 600] The storage device 600 is a freezer that utilizes the cold energy of the ice slurry I to maintain the frozen state of the cold storage material 800 frozen by the cooling device 500.

[0055] As shown in FIG. 5, the storage device 600 has a storage chamber 610 for storing the frozen cold storage material 800, and a storage chamber 620 adjacent to the storage chamber 610 for storing the ice slurry I. A wall 630 separating the storage chamber 610 from the storage chamber 620 is made of a material with a high thermal conductivity, such as aluminum or stainless steel. Therefore, the cold energy of the ice slurry I stored in the storage chamber 620 is efficiently transferred to the storage chamber 610 through the wall 630. This cools the storage chamber 610, and the frozen state of the cold storage material 800 in the storage chamber 610 is maintained. This step is the storage step.

[0056] The storage chamber 620 is connected to the storage tank 420 by pipes 641 and 642, and the ice slurry I in the storage tank 420 circulates between the storage chamber 620 and the ice slurry I. Specifically, the ethanol aqueous solution melted by heat exchange with the storage chamber 610 is returned to the storage tank 420 via pipe 641, and fresh ice slurry I in the storage tank 420 is supplied to the storage chamber 620 via pipe 642, so that the ice slurry I in the storage chamber 620 is maintained at a predetermined amount or more. Therefore, the ice slurry I is not depleted from the storage chamber 620, and the storage chamber 610 can be continuously and efficiently cooled, and the frozen state of the cold storage material 800 is more reliably maintained.

[0057] Although the storage device 600 has been described above, the configuration of the storage device 600 is not particularly limited as long as the frozen state of the cold storage material 800 can be maintained using the ice slurry I. For example, similar to the cooling device 500, the cold storage material 800 may be immersed in the ice slurry I to maintain the frozen state of the cold storage material 800. In addition, for example, the storage tank 420 and the storage chamber 620 may not be connected, and the ice slurry I in the storage tank 420 may be transported to the storage chamber 620 by an operator. In addition, the cold storage material 800 frozen in the cooling device 500 may be automatically transported to the storage chamber 610 by a conveyor or the like.

[0058] In this way, the cooling device 500 and the storage device 600 consume ice slurry I to freeze and store the cold storage material 800, but by generating ice slurry I equal to or greater than the consumption amount in the second heat exchange unit 400, the ice slurry I in the cooling device 500 and the storage device 600 does not run out. In addition, the ethanol aqueous solution itself only repeats state changes between liquid and slurry within the device, and the absolute amount does not substantially decrease. In this way, by repeating the generation and consumption of ice slurry I within the device, it becomes unnecessary to replenish the ethanol aqueous solution, and maintenance is easy. In addition, the cold energy utilization device 200 has excellent energy efficiency.

[0059] The frozen cold storage material 800 stored in the storage device 600 as described above is transported to a required location using, for example, a refrigerated vehicle and used at the transport destination. The transport destination and use of the cold storage material 800 there are not particularly limited, but examples include cooling food (suppressing temperature rise) and cooling a room. Specifically, as shown in FIG. 6, the frozen cold storage material 800 may be stored together with food F in a thermal insulation case 700. This makes it possible to suppress a temperature rise of the food, and to maintain the freshness of the food for a longer period of time. In addition, for example, as shown in FIG. 7, the frozen cold storage material 800 may be placed in a building B. The room can be cooled by introducing air cooled by the cold energy of the cold storage material 800 into the room. However, the method of cooling the food and the method of cooling the room are not particularly limited.

[0060] The cold storage material 800 that has been used for cooling and melted is collected by various means, frozen again by the cooling device 500, and stored in the frozen state in the storage device 600. In this way, by establishing a circulation cycle for the cold storage material 800, substantially no hardware (materials) are discarded, resulting in the cold energy utilization device 200 with an extremely small environmental impact. This further increases the value of the cold energy utilization device 200.

[0061] The cold energy utilization device 200 has been described above, but the configuration of the cold energy utilization device 200 is not particularly limited as long as it can cool the cold storage material 800 by heat exchange with the LNG before it is stored in the tank 110. For example, the primary refrigerant may be omitted, and the LNG introduced from the receiving pipe 170 may directly exchange heat with the secondary refrigerant. Also, for example, the first heat exchanger 310, the condenser 320, the second heat exchanger 410, and the storage tank 420 may be provided in parallel or in series. This can increase the processing capacity. Also, the installation location of the cold energy utilization device 200 is not particularly limited, and may be other than the receiving terminal 100, and may naturally be other than Japan.

[0062] Furthermore, the connection point of the cold energy utilization device 200 to the plant 160 is not particularly limited as long as it is possible to use LNG before it is introduced into the tank 110. For example, it may be connected between an LNG tanker and the receiving pipe 170, or it may be connected between the receiving pipe 170 and the tank 110.

[0063] <Second embodiment> The cold energy utilization device 200 according to this embodiment is similar to the cold energy utilization device 200 according to the first embodiment, except that it has a tank 180 for storing LNG. In the following description, the cold energy utilization device 200 according to this embodiment will be described with a focus on the differences from the first embodiment, and descriptions of similar points will be omitted. In addition, in each drawing of this embodiment, the same reference numerals are used for configurations similar to those of the above-mentioned embodiment.

[0064] As shown in FIG. 8, in the cold energy utilization device 200 of this embodiment, a tank 180 for temporarily storing LNG introduced from the receiving pipe 170 is provided in the middle of the pipeline 331 and upstream of the liquid delivery pump 340. Although it varies depending on the size of the receiving terminal 100 and the amount of LNG consumed, LNG is generally supplied from an LNG tanker once a week or once every two weeks, so in the first embodiment described above, there is a risk that the ice slurry I can only be generated at that timing. In contrast, by providing the tank 180 for temporarily storing LNG as in this embodiment, even when LNG is not being supplied from the LNG tanker, the ice slurry I can be continuously generated using the LNG stored in the tank 180. Therefore, the operable time of the cold energy utilization device 200 is extended.

[0065] The second embodiment as described above can also achieve the same effects as the first embodiment described above.

[0066] <Third embodiment> The cold energy utilization device 200 according to this embodiment is similar to the cold energy utilization device 200 according to the first embodiment described above, except for the configuration of the second heat exchanger 410. In the following description, the cold energy utilization device 200 according to this embodiment will be described focusing on the differences from the first embodiment described above, and the description of the similar points will be omitted. In the drawings of this embodiment, the same reference numerals are used for the same configurations as those in the above-mentioned embodiment.

[0067] As shown in Fig. 9, the second heat exchanger 410 is composed of a flake ice manufacturing device 900. The flake ice manufacturing device 900 is a device that produces flake ice, and includes a drum 910, a rotating shaft 920, a spray unit 930, a blade 950, and a storage tank 970. A spiral pipe 911 through which HCF (primary refrigerant) circulates is embedded in the drum 910. The inner circumferential surface of the drum 910 is cooled by the HFC circulating in the pipe 911. The rotating shaft 920 is disposed on the central axis of the drum 910, and rotates about the central axis by a drive source (not shown), such as a motor.

[0068] The spray unit 930 is fixed to the rotating shaft 920 and rotates together with the rotating shaft 920. The spray unit 930 sprays salt water toward the inner circumferential surface of the drum 910. The salt water sprayed from the spray unit 930 adheres to the inner circumferential surface of the drum 910 cooled by the HCF and instantly freezes into ice. The blade 950 is fixed to the rotating shaft 920 and rotates together with the rotating shaft 920 to scrape off ice formed on the inner circumferential surface of the drum 910. The scraped off ice falls downward as flake ice and is stored in a storage tank 970 arranged directly below the drum 910. The flake ice stored in the storage tank 970 is used for cooling in the cooling device 500 and the storage device 600.

[0069] The third embodiment as described above can also achieve the same effects as the first embodiment described above.

[0070] The cold energy utilization method and cold energy utilization device of the present invention have been described above based on the illustrated embodiment, but the present invention is not limited to this, and the configuration of each part can be replaced with any configuration having a similar function. In addition, any other configuration or any process may be added to the present invention. In addition, each embodiment may be appropriately combined.

[0071] In addition, in the above-described embodiment, a case has been described in which slurry ice and flake ice are produced in the second heat exchanger 410, but the form of the ice is not particularly limited and may be, for example, cube-shaped or block-shaped ice. [Explanation of symbols]

[0072] 100...receiving terminal, 110...tank, 120...evaporator, 130...pipe, 140...pump, 150...odorizer, 160...plant, 170...receiving piping, 180...tank, 200...cold energy utilization device, 300...first heat exchange unit, 310...first heat exchanger, outer pipe...shell, 312...inner pipe, 320...condenser, 321...outer pipe, 322...inner pipe, 331...pipe, 332...pipe, 333...pipe, 333a...pipe, 333b...pipe, 333c...pipe, 334...pipe, 340...liquid transfer pump, 350...expansion valve, 360...flow rate control valve, 380...valve, 390...liquid transfer pump, 400...second heat exchange unit, 4 10...second heat exchanger, 411...outer pipe, 412...inner pipe, 420...storage tank, 441...pipe, 442...pipe, 443...pipe, 444...pipe, 450...liquid feed pump, 460...expansion valve, 470...liquid feed pump, 500...cooling device, 510...cooling tank, 511...cooling tank, 521...pipe, 522...pipe, 530...shelf, 600...storage device, 610...storage room, 620...storage room, 630...wall, 641...pipe, 642...pipe, 700...thermal insulation case, 800...cold storage material, 900...flake ice generating device, 910...drum, 911...piping, 920...rotating shaft, 930...spray section, 950...blade, 970...storage tank, I...ice slurry

Claims

1. It is used in connection with a plant having a tank for storing liquefied gas, A method for utilizing cold energy, comprising: cooling an object by heat exchange with the liquefied gas before it is stored in the tank.

2. The plant has a receiving pipe that connects a carrier that transports the liquefied gas to the tank and guides the liquefied gas from the carrier to the tank, The method for utilizing cold energy according to claim 1 , wherein the liquefied gas is introduced through the receiving pipe.

3. a first heat exchange step of cooling a primary refrigerant by heat exchange with the liquefied gas; The method for utilizing cold energy according to claim 1 , further comprising: a second heat exchange step of cooling a secondary refrigerant by heat exchange with the primary refrigerant.

4. The method for utilizing cold energy according to claim 3, wherein the liquefied gas used in the first heat exchange step is returned to the plant in a liquid state.

5. The first heat exchange step includes a primary refrigerant cooling step of cooling the primary refrigerant by heat exchange with the liquefied gas; The method for utilizing cold energy according to claim 3, further comprising a condensing step of condensing the liquefied gas at least a part of which is gasified by the primary refrigerant cooling step.

6. The method for utilizing cold energy according to claim 5 , wherein the first heat exchange step further includes a depressurizing step of depressurizing the liquefied gas prior to the primary refrigerant cooling step.

7. The method for utilizing cold energy according to claim 5, wherein in the condensing step, the liquefied gas that has undergone the primary refrigerant cooling step is condensed by heat exchange with the liquefied gas that has not undergone the primary refrigerant cooling step.

8. The method for utilizing cold energy according to claim 3 , further comprising an object cooling step of cooling the object by using the secondary refrigerant cooled in the second heat exchange step.

9. The method for utilizing cold energy according to claim 8, further comprising a storage step of storing the object cooled in the object cooling step in a cooled state using the secondary refrigerant cooled in the second heat exchange step.

10. The method for utilizing cold energy according to claim 8, wherein in the second heat exchange step, a part of the secondary refrigerant is frozen to form a slurry.

11. The object is a cold storage material, In the object cooling step, the unfrozen cold storage material is frozen, The method for utilizing cold energy according to claim 9, wherein in the storing step, the cold storage material is stored in a frozen state.

12. The method for utilizing cold energy according to claim 1, wherein the liquefied gas is liquefied natural gas or liquefied petroleum gas.

13. It is used in connection with a plant having a tank for storing liquefied gas, A cold energy utilization device, characterized in that an object is cooled by heat exchange with the liquefied gas before it is stored in the tank.

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