Refrigerated container

Abstract

To provide a freezing container capable of suppressing the gasification of liquefied gas in a liquefied gas tank.SOLUTION: A freezing container which is constructed to cool gas in a container body, includes the container body, a circulation line having an inlet port and an outlet port provided in the container body, a compressor provided in the circulation line and constructed to compress the gas sucked from the inside of the container body via the inlet port into the circulation line, a heat exchanger provided in the circulation line and constructed to cool the gas compressed by the compressor, an expander provided in the circulation line and constructed to expand the gas cooled by the heat exchanger, and the liquefied gas tank stored in the container body and constructed to reserve the liquefied gas.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a refrigerated container configured to be able to cool gas inside a container body. [Background technology]

[0002] A refrigerated container is a container equipped with a refrigeration function for freezing or refrigerating goods such as cargo stored therein.

[0003] Conventional refrigerated containers have a closed cycle for circulating a working fluid, and some use a refrigerator that uses the evaporation and condensation action of the working fluid circulating in the closed cycle. If the refrigerated container is a CA (Controlled Atmosphere) container that can adjust the constituent concentrations of the air (for example, the concentrations of oxygen and carbon dioxide), dedicated equipment such as a flow path that extracts air from inside the container and sends it to a membrane that separates oxygen, and an air compressor, are required in addition to the refrigerator (see Patent Document 1).

[0004] When transporting cryogenic fuel (liquefied gas) such as liquefied natural gas or liquid hydrogen, the transport may be carried out in a tank container for storing the cryogenic fuel, rather than in the above-mentioned refrigerated container (see Patent Document 2). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 2635536 [Patent Document 2] Japanese Patent Application Laid-Open No. 2007-46714 Summary of the Invention [Problem to be solved by the invention]

[0006] Cryogenic fuel (liquefied gas) stored in a tank container gasifies due to the temperature difference with the atmosphere, creating high pressure inside the tank container, which could lead to the tank container exploding. Therefore, boil-off gas generated inside the tank container is released or burned outside the tank container to reduce the internal pressure of the tank container. This could result in a decrease in the amount of cryogenic fuel (liquefied gas) inside the tank container while the tank container is being transported or while it is in standby.

[0007] If the tank of the tank container described above were to be housed in the refrigerated container described in Patent Document 1, the following problems are expected. The refrigerated container described in Patent Document 1 has equipment dedicated to CA containers, equipment constituting a refrigeration unit (evaporator), and equipment for circulating air inside the container (fan and motor) installed inside the container, which reduces the cargo space inside the container. Also, defrosting operation is required to remove frost that has adhered to the evaporator (heat exchanger) placed inside the container, which could reduce the low-temperature reliability of the cargo inside the container. Also, since a heating element such as a motor is placed inside the container, high-temperature areas and temperature unevenness may occur inside the container.

[0008] The refrigerated container described in Patent Document 1 has a small cargo space inside, so the tanks that can be accommodated therein are small. Because small tanks have a relatively small surface area relative to their internal volume, the cryogenic fuel (liquefied gas) inside the tank is easily liquefied by heat input from outside, which poses a problem of a high risk of gasification of the cryogenic fuel (liquefied gas) inside the tank.

[0009] In view of the above circumstances, at least one embodiment of the present invention aims to provide a refrigeration container that can suppress gasification of liquefied gas in a liquefied gas tank. [Means for solving the problem]

[0010] A refrigerated container according to at least one embodiment of the present invention comprises: A refrigeration container configured to be able to cool gas inside a container body, the container body; a circulation line having an inlet and an outlet respectively provided inside the container body; a compressor provided in the circulation line and configured to compress the gas sucked into the circulation line from inside the container body through the suction port; a heat exchanger provided in the circulation line and configured to cool the gas compressed in the compressor; an expander provided in the circulation line and configured to expand the gas cooled by the heat exchanger; and a liquefied gas tank accommodated inside the container body and configured to store liquefied gas. [Effects of the Invention]

[0011] According to at least one embodiment of the present invention, there is provided a refrigerated container that can suppress gasification of liquefied gas in a liquefied gas tank. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a schematic perspective view of a refrigerated container according to one embodiment; FIG. [Figure 2] FIG. 2 is a schematic perspective view of the refrigerated container shown in FIG. 1, viewed from another direction. [Figure 3] FIG. 2 is a diagram schematically illustrating a circuit of a refrigeration unit of a refrigeration container according to an embodiment. [Figure 4] FIG. 3 is a view of a refrigeration container according to one embodiment, as viewed from the direction indicated by arrow A in FIG. 2. [Figure 5] 5 is a view of the refrigeration container shown in FIG. 4 as seen from the direction indicated by arrow B in FIG. 2. [Figure 6] 1 is a schematic diagram of a separation device for a refrigerated container according to an embodiment; [Figure 7] FIG. 2 is a diagram schematically illustrating a circuit of a refrigeration unit of a refrigeration container according to an embodiment. [Figure 8] FIG. 2 is a diagram schematically illustrating a circuit of a refrigeration unit of a refrigeration container according to an embodiment. [Figure 9] FIG. 2 is a diagram schematically illustrating a circuit of a refrigeration unit of a refrigeration container according to an embodiment. [Figure 10] FIG. 2 is a diagram schematically illustrating a circuit of a refrigeration unit of a refrigeration container according to an embodiment. [Figure 11] 1 is a schematic cross-sectional view showing a cross section perpendicular to the longitudinal direction of a refrigerated container according to one embodiment. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0013] 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.

[0014] (Configuration of refrigerated container) Fig. 1 is a schematic perspective view of a refrigerated container 100 according to one embodiment. Fig. 2 is a schematic perspective view of the refrigerated container 100 shown in Fig. 1, viewed from another direction. In Fig. 2, the interior of the refrigerated container 100 is shown by omitting some of the walls that constitute the refrigerated container 100.

[0015] As shown in Figures 1 and 2, the refrigerated container 100 comprises a container body 1 having an inner space 2 capable of accommodating goods such as cargo. The refrigerated container 100 is configured to be able to cool gas such as air inside the container body 1 (i.e., the inner space 2). The container body 1 has a plurality of walls 4 to 9 that form the inner space 2. Each of the plurality of walls 4 to 9 separates the inner space 2 and an outer space 3 of the container body 1. The plurality of walls 4 to 9 include a ceiling wall 4, a bottom wall 5, a pair of short side walls 6, 7, and a pair of long side walls 8, 9.

[0016] The container body 1 may be a shipping container used for transporting cargo, etc. The container body 1 may be a standard shipping container such as a 10 ft container, a 20 ft container, or a 40 ft container.

[0017] Fig. 3 is a diagram schematically showing the circuit of the refrigeration machine (refrigeration cycle) of the refrigeration container 100 according to one embodiment. Fig. 4 is a diagram of the refrigeration container 100 according to one embodiment, viewed from the direction indicated by arrow A in Fig. 2 (longitudinal direction of the container body 1). Fig. 5 is a diagram of the refrigeration container 100 shown in Fig. 4, viewed from inside the container body 1 in the direction indicated by arrow B in Fig. 2 (opposite direction to Fig. 4).

[0018] 2 to 5, the inner space 2 of the container body 1 is provided with a blowout section 14 including a blowout port 16 (opening) for blowing gas such as air into the inside of the container body 1, and a suction section 18 including a suction port 20 for sucking gas such as air into the inside of the container body 1. Note that the blowout section 14 and the suction section 18 are not shown in FIGS. 3 to 5.

[0019] (freezer) 3 to 5, the refrigerated container 100 includes a circulation line 22 having the above-mentioned suction port 20 and outlet 16, a compressor 24, a heat exchanger 26, and an expander 28. The compressor 24, the heat exchanger 26, and the expander 28 are each provided on the circulation line 22. The circulation line 22, the compressor 24, the heat exchanger 26, and the expander 28 form a refrigeration machine (refrigeration cycle) 30 that uses gas inside the container body 1 (internal gas) as a refrigerant. The refrigerated container 100 is capable of adjusting the temperature of the internal gas by the refrigeration machine 30.

[0020] The circulation line 22 is a passage extending from the suction port 20 to the discharge port 16, and allows gas sucked from inside the container body 1 via the suction port 20 to flow through the circulation line 22. The compressor 24 is configured to compress the gas sucked into the circulation line 22 from inside the container body 1 via the suction port 20. By driving the compressor 24, the gas inside the container body 1 is sucked into the circulation line 22 via the suction port 20. The gas compressed in the compressor 24 has a higher temperature and pressure than before it was introduced into the compressor 24, and becomes high-temperature, high-pressure gas.

[0021] The heat exchanger 26 is configured to cool the high-temperature, high-pressure gas compressed in the compressor 24. The expander 28 is configured to expand the gas cooled in the heat exchanger 26. The low-temperature gas expanded in the expander 28 is guided to the outlet 16 by the circulation line 22 and blown out from the circulation line 22 into the inside of the container body 1 via the outlet 16.

[0022] The circulation line 22 includes an intake gas line 22A for guiding the gas sucked from the intake port 20 to the compressor 24, a compressed gas line 22B for guiding the gas compressed in the compressor 24 to the expander 28, and an expanded gas line 22C for guiding the gas expanded in the expander 28 to the discharge port 16.

[0023] (heat exchanger) The heat exchanger 26 is configured to exchange heat between the gas flowing through the suction gas line 22A and the gas flowing through the compressed gas line 22B. The gas flowing through the compressed gas line 22B is compressed in the compressor 24 and has a higher temperature than the gas flowing through the suction gas line 22A. Through the heat exchange in the heat exchanger 26, the gas flowing through the compressed gas line 22B is cooled by the gas flowing through the suction gas line 22A, and the gas flowing through the suction gas line 22A is heated by the gas flowing through the compressed gas line 22B.

[0024] (cooler) As shown in Figures 3 and 4, the refrigerated container 100 may further include a cooler 32 provided in the circulation line 22 between the compressor 24 and the heat exchanger 26. The cooler 32 is provided upstream of the heat exchanger 26 in the compressed gas line 22B, and is configured to exchange heat between the gas flowing in the compressed gas line 22B (circulation line 22) and a cooling liquid (e.g., water) that is cooler than the gas. As a result of the heat exchange in the cooler 32, the gas flowing through the compressed gas line 22B toward the heat exchanger 26 is cooled by the cooling liquid. The gas cooled in the cooler 32 is introduced into the heat exchanger 26 through the compressed gas line 22B.

[0025] In the embodiment shown in Figures 3 and 4, the refrigerated container 100 further includes a coolant circulation line 34 for circulating the coolant. The coolant is supplied to the cooler 32 via the coolant circulation line 34. Specifically, the coolant circulation line 34 is provided with a radiator 38 constituting a cooling device 36 for cooling the coolant, and a pump 42 for sending the coolant through the coolant circulation line 34. The cooling device 36 includes the radiator 38 and a fan 40 for air-cooling the radiator 38. The coolant whose temperature has been increased in the cooler 32 by heat exchange with the gas flowing through the compressed gas line 22B is sent to the coolant circulation line 34 by the pump 42 and is cooled by the cooling device 36 including the radiator 38. The coolant cooled by the cooling device 36 is supplied to the cooler 32 via the coolant circulation line 34.

[0026] (Compressor, expander) In some embodiments, the expander 28 may be coupled to the compressor 24 via a rotating shaft 44. In the embodiment shown in FIGS. 3 and 4 , the compressor 24 and the expander 28 are coaxially arranged with each other via the rotating shaft 44, which is the output shaft of a motor 46 for driving the compressor 24, and are each connected to the rotating shaft 44. The motor 46 is supplied with current from a power source (such as a generator) (not shown), and is driven by the current supplied from the power source to drive the rotating shaft 44, the compressor 24, and the expander 28. The expander 28 recovers a portion of the expansion energy generated when the gas expands, and the recovered expansion energy assists in driving the compressor 24.

[0027] 4, each of the suction gas line 22A, the compressed gas line 22B, and the expanded gas line 22C is formed by a pipe. Note that each pipe forming the circulation line 22 may be formed by connecting multiple pipe sections via flanges or the like.

[0028] 4, the piping forming the suction gas line 22A includes a piping 23A provided between the suction port 20 and the inlet of the heat exchanger 26, and a piping 23B provided between the outlet of the heat exchanger 26 and the compressor 24. The piping forming the compressed gas line 22B includes a piping 23C provided between the outlet of the compressor 24 and the inlet of the cooler 32, a piping 23D provided between the outlet of the cooler 32 and the inlet of the heat exchanger 26, and a piping 23E provided between the outlet of the heat exchanger 26 and the inlet of the expander 28. The piping forming the expanded gas line 22C includes a piping 23F provided between the outlet of the expander 28 and the discharge port 16.

[0029] (separation device) Fig. 6 is a schematic diagram of the oxygen separation device 50 of the refrigerated container 100 according to one embodiment. Each of Figs. 7 to 10 is a diagram schematically showing the circuit of the refrigerator 30 of the refrigerated container 100 according to one embodiment. As shown in Figures 3, 4 and 7 to 10, a refrigerated container 100 according to some embodiments comprises the container body 1 described above, the circulation line 22 described above, the compressor 24 described above, the heat exchanger 26 described above, the expander 28 described above, and a liquefied gas tank 110 accommodated inside the container body 1 and configured to store liquefied gas.

[0030] 1 and 2, the liquefied gas tank 110 is cylindrical with its longitudinal direction aligned axially, and both ends in the longitudinal direction are closed. The longitudinal direction of the liquefied gas tank 110 is arranged along the longitudinal direction of the container body 1. An internal space 111 (see FIG. 3) for storing liquefied gas is formed inside the liquefied gas tank 110. Liquefied gas is stored inside the liquefied gas tank 110.

[0031] The liquefaction temperature (or boiling point) of the liquefied gas stored inside the liquefied gas tank 110 is lower than the liquefaction temperature (or boiling point) of water. The liquefied gas is in a liquid state inside the liquefied gas tank 110. The liquefied gas stored inside the liquefied gas tank 110 may be a liquefied flammable gas (for example, a cryogenic fuel that must be stored at a cryogenic temperature to maintain its liquid state) such as liquefied natural gas (liquefaction temperature: approximately -163°C) or liquid hydrogen (liquefaction temperature: approximately -253°C), or may be a liquefied inert gas such as liquefied carbon dioxide (liquefaction temperature: approximately -76°C) or liquid nitrogen (liquefaction temperature: approximately -196°C).

[0032] The refrigerator 30 cools the inside of the container body 1, thereby keeping the liquefied gas tank 110 accommodated inside the container body 1 cold. This keeps the temperature of the liquefied gas inside the liquefied gas tank 110 below the liquefaction temperature of the liquefied gas, thereby suppressing gasification of the liquefied gas.

[0033] According to the above configuration, a refrigeration machine (refrigeration cycle) 30 is constructed, which includes the compressor 24, the heat exchanger 26, and the expander 28, each of which is provided in the circulation line 22, and which uses the gas inside the container body 1 (internal gas) as a refrigerant. The gas inside the container body 1 naturally circulates from the outlet 16 to the inlet 20 due to the difference in pressure between the outlet 16 and the inlet 20, eliminating the need for a fan to circulate the internal gas. Therefore, the internal temperature does not increase due to the provision of a fan and fan motor inside the container body 1. This makes it easier to maintain the internal temperature at a desired level. Furthermore, since a fan and fan motor are not provided inside the container body 1, a large cargo space can be secured inside the container. Therefore, according to the above configuration, a refrigeration container 100 can be obtained that can prevent a reduction in the cargo space inside the container and maintain a stable internal temperature.

[0034] According to the above configuration, gasification of the liquefied gas in the liquefied gas tank 110 housed inside the container can be suppressed by keeping the internal gas cool using the refrigerator 30. In this case, it is not necessary to use an expensive insulating material with a relatively high insulating efficiency as the insulating material attached to the liquefied gas tank 110, thereby reducing the manufacturing cost of the liquefied gas tank 110. Furthermore, according to the above configuration, by suppressing a reduction in the cargo space inside the container, the liquefied gas tank 110 can be made large with a relatively large surface area relative to the internal volume, thereby reducing the risk of gasification of the liquefied gas in the liquefied gas tank 110 compared to a small tank.

[0035] 1, the above-described refrigerated container 100 further includes at least one support member (support leg in the illustrated example) 120 that supports the liquefied gas tank 110 so that gaps through which gas inside the container body 1 can flow are formed between each of the plurality of walls 4 to 9 and the liquefied gas tank 110. The liquefied gas tank 110 is supported by the at least one support member 120 inside the container body 1 in a floating state above the bottom wall 5.

[0036] According to the above configuration, gas inside the container body 1 flows through the gaps formed between each of the multiple walls 4 to 9 and the liquefied gas tank 110, thereby effectively cooling the entire liquefied gas tank 110, thereby effectively suppressing gasification of the liquefied gas inside the liquefied gas tank 110.

[0037] (Oxygen separation device) In some embodiments, the refrigerated container 100 described above further comprises an oxygen separation device 50, as shown in Figures 3, 4 and 7-10, provided in the circulation line 22 and configured to separate oxygen from the gas compressed in the compressor 24.

[0038] 6, the oxygen separation device 50 includes a membrane module 52 formed by bundling hollow fiber membranes, and a casing 51 that houses the membrane module 52. The casing 51 is provided with a gas inlet 54 for introducing the gas compressed in the compressor 24 into the casing 51, an unseparated gas outlet 56 for discharging unseparated gas (e.g., nitrogen) that remains without being separated from the gas (e.g., air) in the membrane module 52, and a separated gas outlet 58 for discharging separated gas (e.g., oxygen, carbon dioxide, moisture, etc.) that is separated from the gas in the membrane module 52.

[0039] In the illustrated embodiment, the oxygen separation device 50 is configured to extract gaseous oxygen from a gas using membrane separation, i.e., by utilizing the difference in permeation rate of each component in the gas through the membrane module 52. Specifically, gaseous oxygen, gaseous carbon dioxide, moisture, etc. have a faster permeation rate through the hollow fiber membrane than gaseous nitrogen. When a gas (e.g., air) is fed into the membrane module 52 through the gas inlet 54, the gaseous oxygen, gaseous carbon dioxide, moisture, etc., which have a faster permeation rate, pass through the hollow fiber membrane and are discharged to the outside of the oxygen separation device 50 through the separated gas outlet 58. Meanwhile, gaseous nitrogen, which has a slower permeation rate, does not pass through the hollow fiber membrane and is discharged to the outside of the oxygen separation device 50 through the unseparated gas outlet 56.

[0040] The oxygen separation device 50 does not have to completely separate gaseous oxygen, gaseous carbon dioxide, moisture, etc. from the gas, but only needs to be configured to extract a portion of the gaseous oxygen, gaseous carbon dioxide, moisture, etc. from the gas. In other words, the gas discharged to the outside of the oxygen separation device 50 through the unseparated gas outlet 56 may contain gaseous oxygen or gaseous carbon dioxide.

[0041] 4, the piping 23D described above includes piping 23G provided between the outlet of the cooler 32 and a gas inlet 54, which is the inlet of the oxygen separation device 50, and piping 23H provided between an unseparated gas outlet 56, which is the outlet of the oxygen separation device 50, and the inlet of the heat exchanger 26. The gas cooled in the cooler 32 is guided to the oxygen separation device 50 via piping 23G. The gas from which oxygen and other components have been separated in the oxygen separation device 50 is guided to the heat exchanger 26 via piping 23H. As a result, the gas returned to the inside of the container body 1 has had oxygen and other components separated therefrom in the oxygen separation device 50.

[0042] According to the above configuration, the oxygen separation device 50 separates oxygen from the gas taken in by the refrigerator 30, thereby enabling concentration adjustment to be performed to reduce the concentration of oxygen contained in the gas inside the container body 1. The refrigerated container 100 can adjust the constituent concentrations of the gas inside the container body 1 (for example, the concentrations of oxygen and carbon dioxide) by performing the above concentration adjustment. Reducing the oxygen concentration of the gas inside the container body 1 can suppress fires and explosions caused by flammable gas. As a result, even if liquefied gas obtained by liquefying flammable gas leaks from the liquefied gas tank 110, fires and explosions caused by the liquefied gas can be suppressed. The refrigerated container 100 including the refrigerator 30 and the oxygen separation device 50 can be suitably used as a container for transporting or storing the liquefied gas tank 110. Furthermore, the refrigerator 30 that uses the internal gas as a refrigerant has a large flow rate of gas flowing through the refrigerator 30. Therefore, the oxygen separation device 50 provided in the refrigerator 30 can increase the speed of concentration adjustment to reduce the oxygen concentration because the flow rate of gas introduced into the oxygen separation device 50 is large.

[0043] Furthermore, according to the above configuration, the refrigerator 30 doubles as equipment for the oxygen separation device 50, and can introduce gas from inside the container body 1 to the oxygen separation device 50 and discharge gas from the oxygen separation device 50 to inside the container body 1, thereby making the refrigerated container 100 more compact and lightweight.

[0044] If the refrigerator 30 does not also serve as the oxygen separation device 50, dedicated piping and equipment are required to introduce gas from inside the container body 1 to the oxygen separation device 50 and to discharge gas from the oxygen separation device 50 to inside the container body 1. This may make it difficult to make the refrigerated container 100 more compact and lightweight. Furthermore, simply making the dedicated piping and equipment smaller reduces the flow rate of gas to the oxygen separation device 50, and therefore it is necessary to increase the power consumption of the motor 46 to compensate for the decrease in the flow rate of gas to the oxygen separation device 50.

[0045] According to the above configuration, the oxygen separation device 50 having the membrane module 52 can extract gaseous oxygen, gaseous carbon dioxide, moisture, and the like from the gas by utilizing the difference in the permeation rate of each gas component in the gas through the membrane module 52. Therefore, according to the above configuration, by filling the inside of the container body 1 with nitrogen, fires and explosions caused by flammable gases can be suppressed.

[0046] When the liquefied gas stored inside the liquefied gas tank 110 is a liquefied flammable gas such as liquefied natural gas or liquefied hydrogen, the refrigerated container 100 preferably includes an oxygen separation device 50. When the liquefied gas stored inside the liquefied gas tank 110 is a liquefied inert gas such as liquefied carbon dioxide or liquid nitrogen, the refrigerated container 100 does not need to include an oxygen separation device 50.

[0047] In some embodiments, the oxygen separation device 50 is preferably provided downstream of the cooler 32 on the circulation line 22 and upstream of the heat exchanger 26, as shown in Figures 3, 4, and 7 to 10. In this case, the oxygen separation device 50 is configured to receive gas cooled in the cooler 32.

[0048] Depending on the operating conditions of the compressor 24, the gas compressed in the compressor 24 may reach a high temperature of approximately 100°C, and if the high-temperature gas is introduced into the oxygen separation device 50 having the membrane module 52, there is a risk of damaging the membrane module 52. According to the above configuration, by pre-cooling the gas to be introduced into the oxygen separation device 50 having the membrane module 52 in the cooler 32, damage to the membrane module 52 due to heat can be suppressed, and the oxygen separation device 50 can be operated safely.

[0049] The oxygen separation device 50 may be provided downstream of the compressor 24 in the circulation line 22 and upstream of the cooler 32 .

[0050] (Bypass line) 7 and 9, in some embodiments, the circulation line 22 includes a main line 64 for guiding the gas compressed in the compressor 24 to the heat exchanger 26, and a bypass line 66 having one end connected to the main line 64 and the other end connected downstream of the connection position P1 of the one end of the main line 64. The oxygen separation device 50 is provided in the bypass line 66.

[0051] 7 and 9, the main line 64 constitutes a part of the compressed gas line 22B. One end of the main line 64 is connected to the outlet of the cooler 32, and the other end is connected to the inlet of the heat exchanger 26. One end of the bypass line 66 is connected to a connection position P1 of the main line 64, and the other end is connected to a connection position P2 located downstream of the connection position P1 of the main line 64 (towards the heat exchanger 26).

[0052] 7 and 9, the refrigerated container 100 comprises a first gas flow rate control valve 68 provided in the main line 64 between a connection position P1 of one end of the bypass line 66 and a connection position P2 of the other end of the bypass line 66, and a second gas flow rate control valve 70 provided in the bypass line 66. Each of the gas flow rate control valves 68, 70 is configured to be able to adjust the flow rate of gas introduced downstream of the gas flow rate control valves 68, 70 by changing the aperture of a valve element (not shown).

[0053] The above configuration makes it easy to adjust the flow rate of the gas introduced into the oxygen separation device 50 provided in the bypass line 66. This improves the controllability of concentration adjustment for reducing the concentration of oxygen contained in the gas inside the container body 1, and ultimately improves the controllability of concentration adjustment of the gas inside the container.

[0054] (Recirculation Line) 8 and 10 , the circulation line 22 includes a main line 64 for guiding the gas compressed in the compressor 24 to the heat exchanger 26, and a recirculation line 72 having one end connected to the main line 64 and the other end connected to a part of the circulation line 22 upstream of the compressor 24. The oxygen separation device 50 is provided in the recirculation line 72.

[0055] 8 and 10, one end of the main line 64 is connected to the outlet of the cooler 32, and the other end is connected to the inlet of the heat exchanger 26. One end of the recirculation line 72 is connected to a connection position P3 of the main line 64, and the other end is connected to a connection position P4 of the suction gas line 22A (circulation line 22) located between the heat exchanger 26 and the compressor 24.

[0056] 8 and 10, the refrigerated container 100 comprises a third gas flow rate control valve 74 provided in the recirculation line 72, and a fourth gas flow rate control valve 76 provided in the main line 64 downstream (towards the heat exchanger 26) of a connection position P3 at one end of the recirculation line 72. Each of the gas flow rate control valves 74, 76 is configured to be able to adjust the flow rate of gas introduced downstream of the gas flow rate control valves 74, 76 by changing the aperture of a valve element (not shown).

[0057] The gas is repeatedly circulated through a closed circuit including the recirculation line 72, which is formed by closing the fourth gas flow control valve 76 and opening the third gas flow control valve 74, so that the gas is introduced into the oxygen separation device 50 multiple times.

[0058] The above configuration makes it easy to adjust the flow rate of the gas introduced into the oxygen separation device 50 provided in the recirculation line 72. This improves the controllability of concentration adjustment to reduce the concentration of oxygen contained in the gas inside the container body 1, and ultimately improves the controllability of concentration adjustment of the gas inside the container. Furthermore, by providing the oxygen separation device 50 in the recirculation line 72, it is not necessary to provide the bypass line 66, which makes it possible to make the refrigerated container 100 more compact and lightweight.

[0059] (oxygen exhaust line) In some embodiments, the above-described refrigerated container 100 further includes an oxygen discharge line 60 for discharging the oxygen separated from the gas in the above-described oxygen separation device 50, as shown in Figures 3, 7, and 8. The oxygen separated from the gas in the oxygen separation device 50 is discharged to the outside of the container body 1 (outside space 3) through the oxygen discharge line 60.

[0060] The oxygen discharge line 60 is formed by piping. In the illustrated embodiment, one end of the oxygen discharge line 60 is connected to the separated gas discharge port 58 of the oxygen separation device 50, and the other end is open to the atmosphere (communicates with the outer space 3). The refrigerated container 100 is equipped with an oxygen discharge amount adjustment valve 62 provided in the oxygen discharge line 60. The oxygen discharge amount adjustment valve 62 is configured to be able to adjust the flow rate of oxygen introduced downstream of the oxygen discharge amount adjustment valve 62 (the other end side) by changing the opening degree of a valve element (not shown).

[0061] (buffer tank) In some embodiments, the above-mentioned refrigerated container 100 further includes a buffer tank 61 configured to store oxygen (separated gas) separated from the gas in the oxygen separation device 50, an oxygen recovery line 60A for guiding the oxygen separated from the gas in the oxygen separation device 50 to the buffer tank 61, and an oxygen return line 63 for returning the oxygen stored in the buffer tank 61 to the inside of the container body 1, as shown in Figures 9 and 10.

[0062] The oxygen recovery line 60A and the oxygen return line 63 are each formed by piping. In the illustrated embodiment, the oxygen recovery line 60A has one end connected to the separated gas outlet 58 of the oxygen separation device 50 having the membrane module 52, and the other end connected to the buffer tank 61. The oxygen return line 63 has one end connected to the buffer tank 61, and the other end connected to the suction gas line 22A (circulation line 22) between the heat exchanger 26 and the compressor 24. The refrigerated container 100 is equipped with an oxygen return amount adjustment valve 65 provided in the oxygen return line 63. The oxygen return amount adjustment valve 65 is configured to be able to adjust the flow rate of oxygen introduced downstream of the oxygen return amount adjustment valve 65 (toward the other end) by changing the aperture of a valve element (not shown).

[0063] According to the above configuration, oxygen (separated gas) separated from gas in the oxygen separation device 50 can be stored in the buffer tank 61 via the oxygen recovery line 60A, and the oxygen stored in the buffer tank 61 can be returned to the inside of the container body 1 via the oxygen return line 63. This makes it possible to quickly adjust the concentration to increase the concentration of oxygen contained in the gas inside the container body 1. For example, when a person enters the inside of the container body 1, the oxygen concentration in the inner space 2 needs to be set to a predetermined concentration or higher to prevent oxygen deficiency, so it is necessary to adjust the concentration to increase the concentration of oxygen contained in the gas inside the container body 1.

[0064] (Air suction line) In some embodiments, the above-described refrigerated container 100 includes an air suction line 78, one end of which is connected to the circulation line 22 upstream of the compressor 24, and the other end of which is open to the atmosphere (communicating with the outer space 3), as shown in FIGS. 9 and 10 .

[0065] The air suction line 78 is formed by piping. In the illustrated embodiment, one end of the air suction line 78 is connected to the suction gas line 22A (circulation line 22) between the heat exchanger 26 and the compressor 24. By driving the compressor 24, air is sucked into the suction gas line 22A from the outside (outer space 3) of the container body 1 via the air suction line 78. The refrigerated container 100 is equipped with an air suction amount adjustment valve 80 provided in the air suction line 78. The air suction amount adjustment valve 80 is configured to be able to adjust the flow rate of air introduced downstream (to one end) of the air suction amount adjustment valve 80 by changing the aperture of a valve element (not shown).

[0066] According to the above configuration, the refrigerator 30 sucks in the gas inside the container body 1, and then returns the gas, from which some components such as oxygen have been removed, to the inside of the container body 1. If this process is repeated and the inside of the container body 1 becomes negative pressure, there is a risk that air will flow in from outside the container body 1. If air flows in from outside the container body 1, there is a risk that the heat of the air will raise the temperature inside the container body 1. According to the above configuration, air is taken in through the air suction line 78 into the circulation line 22, and the gas from which oxygen has been separated is introduced into the container body 1, thereby creating a positive pressure inside the container body 1. Creating a positive pressure inside the container body 1 prevents air from flowing in from outside the container body 1.

[0067] In some embodiments, the refrigerated container 100 described above includes the air suction line 78 described above and a gas discharge line 82 for discharging the gas compressed in the compressor 24 to the outside of the circulation line 22, as shown in FIGS. 9 and 10.

[0068] The gas discharge line 82 is formed by piping. In the illustrated embodiment, one end of the gas discharge line 82 is connected to the circulation line 22 downstream of the cooler 32 and upstream of the heat exchanger 26, and the other end is open to the atmosphere (communicates with the outer space 3). When the compressor 24 is driven, a pressure difference occurs between one end and the other end of the gas discharge line 82, causing gas to be discharged from the circulation line 22 to the outside of the container body 1 (the outer space 3) via the gas discharge line 82. The refrigerated container 100 is equipped with a gas discharge amount adjustment valve 84 provided in the gas discharge line 82. The gas discharge amount adjustment valve 84 is configured to be able to adjust the flow rate of gas introduced downstream of the gas discharge amount adjustment valve 84 (the other end side) by changing the aperture of a valve element (not shown).

[0069] According to the above configuration, pressure control for lowering the pressure inside the container body 1 becomes possible by discharging gas to the outside of the circulation line 22 via the gas discharge line 82. This makes it possible to perform the concentration adjustment inside the container body 1 without increasing the pressure inside the container body 1.

[0070] (Layout of equipment that makes up the refrigerator) In some embodiments, as shown in Figures 1 and 4, each of the compressor 24, cooler 32, heat exchanger 26, expander 28, and oxygen separation device 50, which are respectively provided in the circulation line 22, is arranged in the outer space 3 of the container body 1 along the partition wall 10 that separates the inner space 2 and the outer space 3 of the container body 1.

[0071] In the illustrated embodiment, the above-described devices provided in the circulation line 22 are arranged along the short side wall 7 serving as the partition wall 10. In FIG. 1, some of the above-described devices provided in the circulation line 22 are schematically indicated by two-dot chain lines.

[0072] As shown in Figures 1 and 4, the above-mentioned refrigeration container 100 may be provided with a cover 12 that is provided so as to enclose the above-mentioned equipment provided in the outer space 3 of the container body 1 from above, below, and sides.

[0073] 4 and 5, the piping 23A between the suction port 20 and the heat exchanger 26 may be provided so as to pass through a through-hole 25 provided in the short side wall 7 (partition wall 10). Also, the piping 23F between the expander 28 and the outlet 16 may be provided so as to pass through a through-hole 27 provided in the short side wall 7 (partition wall 10).

[0074] According to the above configuration, the compressor 24, the cooler 32, the heat exchanger 26, the expander 28, and the oxygen separation device 50 are each installed in the outer space 3 of the container body 1. In other words, because these devices are not installed in the inner space 2 of the container body 1, a large cargo space can be secured inside the container. Furthermore, with the above configuration, it is not necessary to install a heat exchanger such as an evaporator in the inner space 2 of the container body 1, and therefore defrosting operation to defrost such a heat exchanger is not necessary. Therefore, it is easy to maintain the temperature inside the container at a desired temperature. Furthermore, with the above configuration, the devices constituting the refrigeration unit 30 and the oxygen separation device 50 are arranged in a relatively narrow space along the partition wall 10 in the outer space 3 of the container body 1. As such, because the installation area of ​​the refrigeration unit 30 and the oxygen separation device 50 added to the container body 1 is small, the refrigeration container 100 including the refrigeration unit 30 and the oxygen separation device 50 can be suitably used as a container for transporting and storing liquefied gas tanks 110.

[0075] In some embodiments, at least one of the heat exchanger 26 or the cooler 32 may include a plate heat exchanger or a microchannel heat exchanger, which may be formed from materials including aluminum or titanium.

[0076] In some embodiments, the suction port 20 is provided with a filter unit 21 for removing foreign matter, as shown in Fig. 5. The filter unit 21 includes a member or the like having a plurality of holes or a mesh, and has a plurality of openings formed by these holes, mesh, or the like.

[0077] In some embodiments, as shown in FIG. 1 , the partition wall 10 (in the example shown in FIG. 1 , the short side wall 7 of the container body 1) that separates the area where the compressor 24, cooler 32, heat exchanger 26, expander 28, and oxygen separation device 50 are installed outside the container body 1 from the internal space 2 of the container body 1 extends along a plane perpendicular to the longitudinal direction of the container body 1.

[0078] In the above-described embodiment, the equipment constituting the refrigeration unit 30 (compressor 24, heat exchanger 26, expander 28) and the oxygen separation unit 50 are arranged in a relatively narrow space along the partition wall 10 (short side wall 7), which is a relatively small wall extending along a plane perpendicular to the longitudinal direction of the container body 1. This makes it possible to reduce the installation area of ​​the refrigeration unit 30 and the oxygen separation unit 50 added to the container body 1, and the refrigerated container 100 including the refrigeration unit 30 and the oxygen separation unit 50 can be suitably used as a container for transporting and storing liquefied gas tanks 110.

[0079] In one embodiment, the compressor 24, cooler 32, heat exchanger 26, expander 28, and oxygen separation device 50 may be arranged in the outer space 3 such that the length L1 from the partition 10 in the longitudinal direction of the container body 1 is within a range of 1 / 10 or less of the length L0 of the container body 1 (see Figure 1).

[0080] In this case, the installation area for the equipment constituting the refrigerator 30 and the oxygen separation device 50 is within a range of 1 / 10 or less of the length L0 of the container body 1. Therefore, since the installation area for the refrigerator 30 and the oxygen separation device 50 added to the container body 1 is small, the refrigerated container 100 including the refrigerator 30 and the oxygen separation device 50 can be suitably used as a container for transporting and storing the liquefied gas tank 110.

[0081] For example, if the container body 1 is a 20-ft container (length L0: approximately 6.1 m, width W0: approximately 2.4 m, height H0: approximately 2.6 m), the length (L1) of the above-mentioned installation area may be 610 mm or less.

[0082] Fig. 11 is a schematic cross-sectional view showing a cross section perpendicular to the longitudinal direction of a refrigerated container according to one embodiment. In some embodiments, as shown in Fig. 11, the above-described refrigerated container 100 has an exhaust port 131 provided inside the container body 1, and further includes a relief line 130 for discharging gas present inside the container body 1 to the outside of the container body 1 via the exhaust port 131.

[0083] The exhaust port 131 is provided outside the liquefied gas tank 110 in the inner space 2 of the container body 1, and connects the inner space 2 with the inside of the relief line 130. The relief line 130 is provided in the outer space 3 of the container body 1, and further has an outer opening 132 that connects the outer space 3 with the inside of the relief line 130. The outer opening 132 is open to the atmosphere (communicates with the outer space 3) outside the cover 12. The relief line 130 is a passage that extends from the exhaust port 131 provided at one end thereof to the outer opening 132 provided at the other end, and gas introduced from inside the container body 1 flows through the exhaust port 131.

[0084] The relief line 130 is formed by piping. As shown in FIG. 11 , the relief line 130 may be provided so as to pass through a through-hole 29 provided in the ceiling wall 4 (partition wall 10). Due to a pressure difference occurring between one end (exhaust port 131) and the other end (outer opening 132) of the relief line 130, gas is discharged from the inner space 2 of the container body 1 to the outside (outer space 3) of the container body 1 through the relief line 130. Note that not only when the inside of the container body 1 is made positive pressure by taking in air into the circulation line 22 through the air suction line 78, but also when liquefied gas in the liquefied gas tank 110 leaks into the inner space 2 of the container body 1, the pressure in the inner space 2 increases and becomes higher than the outer space 3. In these cases, air can be discharged from the inside of the container body 1 through the relief line 130.

[0085] As shown in FIG. 11 , the refrigerated container 100 may further include a relief valve 133 provided in the relief line 130. The relief valve 133 is configured to be able to adjust the flow rate of gas introduced into the relief line 130 downstream of the relief valve 133 (toward the outer opening 132) by changing the opening degree of a valve element (not shown). Furthermore, the relief valve 133 may be provided outside the container body 1, specifically, downstream of the portion of the relief line 130 that is inserted into the through-hole 29 (toward the outer opening 132), so that manual operation from outside the container body 1 can be easily performed. Opening the relief valve 133 makes it possible to vent air from the inside of the container body 1 via the relief line 130. The relief valve 133 may be configured to automatically operate when the pressure in the inner space 2 exceeds a predetermined pressure.

[0086] According to the above configuration, if liquefied gas leaks from the liquefied gas tank 110, the gas leaked into the container body 1 (gas obtained by vaporizing the liquefied gas) can be discharged to the outside of the container body 1 through the relief line 130. This prevents the gas leaked into the container body 1 from remaining inside the container body 1 or in the circulation line 22, thereby preventing oxygen deficiency caused by the gas for people who enter the container body 1 and suppressing fires and explosions caused by the gas.

[0087] In some embodiments, as shown in FIG. 11 , the above-described refrigerated container 100 has a boil-off gas inlet 141 provided inside the liquefied gas tank 110, and further includes a boil-off gas line 140 for discharging boil-off gas, which is liquefied gas vaporized in the liquefied gas tank 110, to the outside of the container body 1 via the boil-off gas inlet 141.

[0088] The boil-off gas inlet 141 is provided in the internal space 111 of the liquefied gas tank 110 and connects the internal space 111 to the interior of the boil-off gas line 140. The boil-off gas line 140 is provided in the external space 3 of the container body 1 and further has an external opening 142 that connects the external space 3 to the interior of the boil-off gas line 140. The external opening 142 is open to the atmosphere (connected to the external space 3) outside the cover 12. The boil-off gas line 140 is a passage extending from the boil-off gas inlet 141 provided at one end thereof to the external opening 142 provided at the other end thereof, and boil-off gas introduced from the interior of the liquefied gas tank 110 flows through the boil-off gas inlet 141.

[0089] The boil-off gas line 140 is formed by piping. As shown in Fig. 11, the boil-off gas line 140 may be provided so as to pass through a through-hole 31 provided in the ceiling wall 4 (partition wall 10) or a through-hole 112 provided in the upper part of the liquefied gas tank 110. Due to a pressure difference generated between one end (boil-off gas inlet 141) and the other end (outer opening 142) of the boil-off gas line 140, boil-off gas is discharged from the internal space 111 of the liquefied gas tank 110 to the outside (outer space 3) of the container body 1 through the boil-off gas line 140.

[0090] As shown in FIG. 11 , the refrigerated container 100 may further include a boil-off gas valve 143 provided in the boil-off gas line 140. The boil-off gas valve 143 is configured to be able to adjust the flow rate of boil-off gas introduced downstream of the boil-off gas valve 143 (toward the outer opening 142) of the boil-off gas line 140 by changing the aperture of a valve element (not shown). Furthermore, the boil-off gas valve 143 may be provided outside the container body 1, specifically, downstream of the portion of the boil-off gas line 140 that is inserted into the through-hole 31 (toward the outer opening 142), so that manual operation from outside the container body 1 can be easily performed. Opening the boil-off gas valve 143 allows boil-off gas to be discharged from the inside of the liquefied gas tank 110 via the boil-off gas line 140.

[0091] According to the above configuration, boil-off gas that has evaporated inside the liquefied gas tank 110 can be discharged to the outside of the container body 1 through the boil-off gas line 140. This makes it possible to prevent the inside of the liquefied gas tank 110 from becoming highly pressurized due to the boil-off gas and to prevent the boil-off gas from leaking into the inner space 2, thereby preventing oxygen deficiency caused by the boil-off gas for people who enter the container body 1 and suppressing fires and explosions caused by the boil-off gas.

[0092] 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.

[0093] The present disclosure is not limited to the above-described embodiments, but also includes modifications to the above-described embodiments and appropriate combinations of these modifications.

[0094] The contents of the above-described embodiments can be understood, for example, as follows.

[0095] 1) A refrigeration container (100) according to at least one embodiment of the present disclosure comprises: A refrigeration container (100) configured to be able to cool gas inside a container body (1), The container body (1), a circulation line (22) having an inlet (20) and an outlet (16) respectively provided inside the container body (1); a compressor (24) provided in the circulation line (22) and configured to compress the gas sucked into the circulation line (22) from inside the container body (1) through the suction port (20); a heat exchanger (26) provided in the circulation line (22) and configured to cool the gas compressed in the compressor (24); an expander (28) provided in the circulation line (22) and configured to expand the gas cooled by the heat exchanger (26); and a liquefied gas tank (110) accommodated inside the container body (1) and configured to store liquefied gas.

[0096] According to the above-described configuration (1), a refrigeration unit (30) is constructed, which includes a compressor (24), a heat exchanger (26), and an expander (28) provided in the circulation line (22), and which uses the gas inside the container body (1) (internal gas) as a refrigerant. The gas inside the container body (1) naturally circulates from the outlet (16) to the inlet (20) due to the difference in pressure between the outlet (16) and the inlet (20). Therefore, a fan for circulating the air inside the container body (1) is not required. Therefore, the internal temperature does not increase due to the provision of a fan and a fan motor inside the container body (1). Therefore, the internal temperature can be easily maintained at a desired temperature. Furthermore, since a fan and a fan motor are not provided inside the container body (1), a large cargo space can be secured inside the container body (1). Therefore, according to the above-described configuration (1), a refrigeration container (100) can be obtained, which can prevent a reduction in the cargo space inside the container and can maintain a stable internal temperature.

[0097] According to the configuration 1), the gas inside the container is kept cool by the refrigerator (30), thereby suppressing gasification of the liquefied gas inside the liquefied gas tank (110) housed inside the container. In this case, it is not necessary to use an expensive insulating material with a relatively high insulating efficiency as the insulating material attached to the liquefied gas tank (110), thereby reducing the manufacturing cost of the liquefied gas tank (110). Furthermore, according to the configuration 1), the cargo space inside the container is prevented from being reduced, so that the liquefied gas tank (110) can be made large with a relatively large surface area relative to the internal volume. This reduces the risk of gasification of the liquefied gas inside the liquefied gas tank (110) compared to a small tank.

[0098] 2) In some embodiments, the refrigerated container (100) described in 1) above, The system further includes an oxygen separator (50) disposed in the circulation line (22) and configured to separate oxygen from the gas compressed in the compressor (24).

[0099] According to the configuration of 2), the oxygen separation device (50) separates oxygen from the gas taken into the refrigerator (30), thereby performing concentration adjustment to reduce the oxygen concentration contained in the gas inside the container body (1). The refrigerated container (100) can adjust the constituent concentrations (e.g., concentrations of oxygen and carbon dioxide) of the gas inside the container body (1) by performing the concentration adjustment. Reducing the oxygen concentration of the gas inside the container body (1) can suppress fires and explosions caused by flammable gas. This suppresses fires and explosions caused by liquefied gas, even if liquefied gas obtained by liquefying flammable gas from the liquefied gas tank (110). The refrigerated container (100) including the refrigerator (30) and the oxygen separation device (50) can be suitably used as a container for transporting or storing the liquefied gas tank (110). Furthermore, the refrigerator (30) that uses the gas inside the container body as a refrigerant has a large flow rate of the gas flowing through the refrigerator (30). Therefore, the oxygen separator (50) provided in the refrigerator (30) can increase the speed of concentration adjustment for reducing the oxygen concentration because the flow rate of the gas introduced into the oxygen separator (50) is large.

[0100] Furthermore, according to the configuration 2), the refrigerator (30) doubles as the oxygen separation device (50) and can introduce gas from inside the container body (1) to the oxygen separation device (50) and discharge gas from the oxygen separation device (50) to inside the container body (1). This makes it possible to make the refrigerated container (100) more compact and lightweight.

[0101] 3) In some embodiments, the refrigerated container (100) described in 2) above, The oxygen separation device (50) has a membrane module (52) in which hollow fiber membranes are bundled together.

[0102] According to the above configuration 3), the oxygen separation device (50) having the membrane module (52) can extract gaseous oxygen, gaseous carbon dioxide, moisture, and the like from the gas by utilizing the difference in the permeation rate of each gas component in the gas through the membrane module (52). Therefore, according to the above configuration 3), by filling the inside of the container body (1) with nitrogen, fires and explosions caused by flammable gases can be suppressed.

[0103] 4) In some embodiments, the refrigerated container (100) described in 3) above, a cooler (32) provided in the circulation line (22) between the compressor (24) and the heat exchanger (26) and configured to perform heat exchange between the gas flowing through the circulation line (22) and a cooling liquid; The oxygen separator (50) is provided on the circulation line (22) downstream of the cooler (32) and upstream of the heat exchanger (26).

[0104] The gas compressed in the compressor (24) may reach a high temperature of approximately 100° C. depending on the operating conditions of the compressor (24). If the high-temperature gas is introduced into the oxygen separation device (50) having the membrane module (52), the membrane module (52) may be damaged. According to the configuration of 4) above, the gas to be introduced into the oxygen separation device (50) having the membrane module (52) is cooled in advance in the cooler (32), thereby preventing damage to the membrane module (52) due to heat. This makes it possible to safely operate the oxygen separation device (50).

[0105] 5) In some embodiments, the refrigeration container (100) according to any one of 2) to 4) above, The circulation line (22) a main line (64) for guiding the gas compressed in the compressor (24) to the heat exchanger (26); a bypass line (66) having one end connected to the main line (64) and the other end connected to the main line (64) downstream of the connection position (P1) of the one end, The oxygen separator (50) was provided in the bypass line (66).

[0106] The configuration of 5) above facilitates adjustment of the flow rate of the gas introduced into the oxygen separator (50) provided in the bypass line (66). This improves the controllability of the concentration adjustment for reducing the concentration of oxygen contained in the gas inside the container body (1), thereby improving the controllability of the concentration adjustment of the constituents of the gas inside the container.

[0107] 6) In some embodiments, the refrigeration container (100) according to any one of 2) to 4) above, The circulation line (22) a main line (64) for guiding the gas compressed in the compressor (24) to the heat exchanger (26); a recirculation line (72) having one end connected to the main line (64) and the other end connected to the circulation line (22) on a side upstream of the compressor (24), The oxygen separator (50) was provided in the recirculation line (72).

[0108] According to the configuration 6), the flow rate of the gas introduced into the oxygen separator (50) provided in the recirculation line (72) can be easily adjusted. This improves the controllability of the concentration adjustment for reducing the oxygen concentration in the gas inside the container body (1), thereby improving the controllability of the concentration adjustment of the oxygen concentration in the gas inside the container body (1). Furthermore, by providing the oxygen separator (50) in the recirculation line (72), the bypass line (66) is not required, which makes it possible to reduce the size and weight of the refrigeration container (100).

[0109] 7) In some embodiments, the refrigeration container (100) according to any one of 2) to 4) above, a buffer tank (61) configured to store the oxygen separated from the gas in the oxygen separation device (50); an oxygen recovery line (60A) for guiding the oxygen separated from the gas in the oxygen separation device (50) to the buffer tank (61); The container further includes an oxygen return line (63) for returning the oxygen stored in the buffer tank (61) to the inside of the container body (1).

[0110] According to the configuration 7), oxygen separated from the gas in the oxygen separation device (50) can be stored in the buffer tank (61) via the oxygen recovery line (60A), and the oxygen stored in the buffer tank (61) can be returned to the inside of the container body (1) via the oxygen return line (63). This makes it possible to quickly adjust the concentration of oxygen contained in the gas inside the container body (1).

[0111] 8) In some embodiments, the refrigeration container (100) according to any one of 2) to 7) above, The air suction system further includes an air suction line (78) having one end connected to the circulation line (22) upstream of the compressor (24) and the other end open to the atmosphere.

[0112] According to the configuration of 8) above, the refrigerator (30) sucks in the gas inside the container body (1), and some of the components, such as oxygen, are removed from the gas and the resulting gas is returned to the container body (1). If this process is repeated, the pressure inside the container body (1) becomes negative, which may cause air to flow in from the outside of the container body (1). If air flows in from the outside of the container body (1), the heat of the air may cause the temperature inside the container body (1) to rise. According to the configuration of 8) above, air is taken into the circulation line (22) via the air suction line (78), and the gas from which oxygen has been separated is introduced into the container body (1), thereby creating a positive pressure inside the container body (1). By creating a positive pressure inside the container body (1), the inflow of air from the outside of the container body (1) can be prevented.

[0113] 9) In some embodiments, the refrigerated container (100) described in 8) above, a cooler (32) provided in the circulation line (22) between the compressor (24) and the heat exchanger (26), configured to perform heat exchange between the gas flowing through the circulation line (22) and a cooling liquid; The system further includes a gas discharge line (82) for discharging the gas compressed in the compressor (24) to the outside of the circulation line (22), the gas discharge line (82) having one end connected to the circulation line (22) downstream of the cooler (32) and upstream of the heat exchanger (26).

[0114] According to the above configuration 9), pressure control for reducing the pressure inside the container body (1) is possible by discharging the gas to the outside of the circulation line (22) through the gas discharge line (82). This makes it possible to adjust the concentration inside the container body (1) without increasing the pressure inside the container body (1).

[0115] 10) In some embodiments, the refrigeration container (100) according to any one of 1) to 9) above, The compressor (24), the heat exchanger (26), and the expander (28) are each arranged in the outer space (3) of the container body (1) along a partition wall (10) that separates the inner space (2) of the container body (1) from the outer space (3).

[0116] According to the configuration of 10), the compressor (24), the heat exchanger (26), and the expander (28) are each installed in the outer space (3) of the container body (1). This means that these components are not installed in the inner space (2) of the container body (1), thereby ensuring a large cargo space inside the container. Furthermore, the configuration of 10) does not require a heat exchanger, such as an evaporator, to be installed in the inner space (2) of the container body (1), eliminating the need for a defrosting operation to defrost the heat exchanger. This makes it easier to maintain the temperature inside the container at a desired level. Furthermore, the configuration of 10) also allows the components of the refrigerator (30) to be installed in a relatively narrow space along the partition wall (10) in the outer space (3) of the container body (1). Because the installation area of ​​the refrigerator (30) added to the container body (1) is thus small, the refrigerated container (100) including the refrigerator (30) can be suitably used as a container for transporting or storing a liquefied gas tank (110).

[0117] 11) In some embodiments, the refrigeration container (100) according to any one of 1) to 10) above, The container further includes a relief line (130) having an exhaust port (131) provided inside the container body (1) and for discharging gas present inside the container body (1) to the outside of the container body (1) through the exhaust port (131).

[0118] According to the configuration 11), if liquefied gas leaks from the liquefied gas tank (110), the gas leaked into the container body (1) (gas formed by vaporizing the liquefied gas) can be discharged to the outside of the container body (1) through the relief line (130). This prevents the gas leaked into the container body (1) from remaining inside the container body (1) or in the circulation line (22), thereby preventing oxygen deficiency caused by the gas for people who enter the container body (1) and suppressing fires and explosions caused by the gas.

[0119] 12) In some embodiments, the refrigeration container (100) according to any one of 1) to 11) above, The container further includes a boil-off gas line (140) having a boil-off gas inlet (141) provided inside the liquefied gas tank (110) and discharging boil-off gas, which is the liquefied gas vaporized in the liquefied gas tank (110), to the outside of the container body (1) through the boil-off gas inlet (141).

[0120] According to the configuration 12), the boil-off gas that has evaporated in the liquefied gas tank (110) can be discharged to the outside of the container body (1) through the boil-off gas line (140). This prevents the boil-off gas from building up a high pressure inside the liquefied gas tank (110) or from leaking into the inner space (2). This prevents oxygen deficiency caused by the boil-off gas for people who enter the container body (1) and prevents fires and explosions caused by the boil-off gas. [Explanation of symbols]

[0121] 1 Container body 2. Inner Space 3 Outside space 4 Ceiling Wall 5 Bottom wall 6,7 Short sidewall 8,9 Long side wall 10 Bulkhead 12 Cover 14. Outlet 16 Air outlet 18 Intake section 20 Intake port 21 Filter section 22 Circulation Line 22A Suction Gas Line 22B Compressed Gas Line 22C Expansion Gas Line 23A~23H Piping 24 Compressor 25, 27, 29, 31, 112 Through holes 26 Heat exchanger 28 Expander 30 Refrigeration Machine 32 Cooler 34 Coolant circulation line 36 Cooling device 38 Radiator 40 fans 42 Pump 44 Rotating shaft 46 Motor 50 Oxygen Separator 51 Casing 52 Membrane module 54 Gas inlet 56 Non-separated gas outlet 58 Separation gas outlet 60 Oxygen exhaust line 60A oxygen recovery line 61 Buffer Tank 62 Oxygen discharge control valve 63 Oxygen return line 64 Main Line 65 Oxygen return amount adjustment valve 66 Bypass Line 68 First gas flow control valve 70 Second gas flow control valve 72 Recirculation Line 74 Third gas flow control valve 76 Fourth gas flow control valve 78 Air suction line 80 Air suction volume adjustment valve 82 Gas exhaust line 84 Gas discharge control valve 100 refrigerated containers 110 Liquefied Gas Tank 120 Support member 130 Relief Line 131 Exhaust port 132 Outer opening 133 Relief valve 140 Boil-off gas line 141 Boil-off gas intake 142 Outer opening 143 Boil-off gas valve

Claims

1. A refrigeration container configured to be able to cool gas inside a container body, the container body; a circulation line having an inlet and an outlet respectively provided inside the container body; a compressor provided in the circulation line and configured to compress the gas sucked into the circulation line from inside the container body through the suction port; a heat exchanger provided in the circulation line and configured to cool the gas compressed in the compressor; an expander provided in the circulation line and configured to expand the gas cooled by the heat exchanger; a liquefied gas tank accommodated inside the container body and configured to store liquefied gas, Refrigerated container.

2. The compressor further includes an oxygen separator provided in the circulation line and configured to separate oxygen from the gas compressed in the compressor.

2. The refrigerated container of claim 1.

3. The oxygen separation device has a membrane module in which hollow fiber membranes are bundled.

3. The refrigerated container of claim 2.

4. a cooler provided in the circulation line between the compressor and the heat exchanger and configured to perform heat exchange between the gas flowing through the circulation line and a cooling liquid; The oxygen separation device is provided downstream of the cooler and upstream of the heat exchanger in the circulation line.

4. The refrigerated container of claim 3.

5. The circulation line is a main line for guiding the gas compressed in the compressor to the heat exchanger; a bypass line having one end connected to the main line and the other end connected to a downstream side of the connection position of the one end of the main line, The oxygen separation device is provided in the bypass line, A refrigerated container according to any one of claims 2 to 4.

6. The circulation line is a main line for guiding the gas compressed in the compressor to the heat exchanger; a recirculation line having one end connected to the main line and the other end connected to the circulation line upstream of the compressor, The oxygen separation device is provided in the recirculation line, A refrigerated container according to any one of claims 2 to 4.

7. a buffer tank configured to store the oxygen separated from the gas in the oxygen separation device; an oxygen recovery line for guiding the oxygen separated from the gas in the oxygen separation device to the buffer tank; an oxygen return line for returning the oxygen stored in the buffer tank to the inside of the container body, A refrigerated container according to any one of claims 2 to 4.

8. an air suction line having one end connected to the circulation line upstream of the compressor and the other end open to the atmosphere; A refrigerated container according to any one of claims 2 to 4.

9. a cooler provided in the circulation line between the compressor and the heat exchanger, configured to perform heat exchange between the gas flowing through the circulation line and a cooling liquid; a gas discharge line for discharging the gas compressed in the compressor to the outside of the circulation line, the gas discharge line having one end connected to the circulation line downstream of the cooler and upstream of the heat exchanger, 9. A refrigerated container according to claim 8.

10. the compressor, the heat exchanger, and the expander are each disposed in the outer space of the container body along a partition wall that separates the inner space of the container body from the outer space. A refrigerated container according to any one of claims 1 to 4.

11. a relief line having an exhaust port provided inside the container body for discharging gas present inside the container body to the outside of the container body via the exhaust port; A refrigerated container according to any one of claims 1 to 4.

12. a boil-off gas line having a boil-off gas inlet provided inside the liquefied gas tank for discharging boil-off gas, which is the liquefied gas vaporized in the liquefied gas tank, to the outside of the container body via the boil-off gas inlet; A refrigerated container according to any one of claims 1 to 4.

Images