Liquefied gas handling method and liquefied gas handling system

Abstract

To perform cargo handling for a liquefied gas without using a pump.SOLUTION: A method of cargo handling for a liquefied gas includes the steps of: storing the same type of gas as evaporation gas, which is formed of an evaporated liquefied gas that is stored in a first pressure container, while being compressed in a gas storage tank; connecting the first pressure container to a second pressure container; and supplying a gas to a gaseous phase part inside the first pressure container from the gas storage tank with internal pressure of the gas storage tank to deliver the liquefied gas to the second pressure container from the first pressure container.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a liquefied gas handling method and a liquefied gas handling system. [Background technology]

[0002] It has been known for some time that liquefied gas is loaded and unloaded from a ship by operating a pump. For example, Patent Document 1 discloses that a pump mounted on an LNG ship is operated to unload gas from a hold tank through a pipe into a land-side tank installed at an LNG receiving terminal. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-206282 Summary of the Invention [Problem to be solved by the invention]

[0004] There is a demand for loading and unloading liquefied gas without using pumps.

[0005] Therefore, an object of the present disclosure is to provide a liquefied gas loading and unloading method and a liquefied gas loading and unloading system that enable unloading of liquefied gas without using a pump. [Means for solving the problem]

[0006] In order to solve the above problems, a method for loading and unloading liquefied gas according to one embodiment of the present disclosure stores compressed gas of the same type as the evaporated gas produced when liquefied gas stored in a first pressure vessel is vaporized in a gas storage tank, connects the first pressure vessel to a second pressure vessel, supplies the gas from the gas storage tank to the gas phase in the first pressure vessel using the pressure in the gas storage tank, and delivers the liquefied gas from the first pressure vessel to the second pressure vessel.

[0007] Furthermore, a liquefied gas loading and unloading system according to one embodiment of the present disclosure is a liquefied gas loading and unloading system for supplying liquefied gas from a first pressure vessel in which liquefied gas is stored to a second pressure vessel, and includes: a gas storage tank for storing compressed gas of the same type as the evaporated gas produced when the liquefied gas stored in the first pressure vessel is evaporated; a gas pipe having one end connected to the gas storage tank and the other end connected or connectable to a pipe extending from the first pressure vessel; and an on-off valve for opening and closing the gas pipe; wherein, when the on-off valve transitions from a closed state to an open state while the first pressure vessel and the second pressure vessel are connected, the gas storage tank supplies the gas to a gas phase portion in the first pressure vessel by the pressure within the gas storage tank, thereby sending the liquefied gas from the first pressure vessel to the second pressure vessel. [Effects of the Invention]

[0008] According to the present disclosure, it is possible to provide a liquefied gas loading and unloading method and a liquefied gas loading and unloading system that enable unloading of liquefied gas without using a pump. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic configuration diagram of a liquefied gas handling system according to one embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, a liquefied gas handling method and a liquefied gas handling system according to one embodiment will be described with reference to FIG.

[0011] <Cargo handling system> 1 is a schematic diagram of a liquefied gas loading and unloading system 3 according to one embodiment. The loading and unloading system 3 is a system for performing loading and unloading between a liquefied gas carrier 1 and an onshore facility 2. In the following explanation, the loading and unloading system 3 is described as a system used for unloading liquefied gas from a first pressure vessel 11 of the liquefied gas carrier 1 to a second pressure vessel 21 of the onshore facility 2. As will be described later, the loading and unloading system 3 can also be applied to loading liquefied gas from the second pressure vessel 21 of the onshore facility 2 to the first pressure vessel 11 of the liquefied gas carrier 1.

[0012] A first pressure vessel 11, which is a cargo tank, is mounted on the hull 10 of the liquefied gas carrier 1. Liquefied gas is stored in the first pressure vessel 11. In this embodiment, the liquefied gas is liquefied hydrogen. However, the liquefied gas may be another type of liquefied gas, such as liquefied natural gas or liquefied petroleum gas.

[0013] The first pressure vessel 11 is capable of storing liquefied gas under high pressure. The first pressure vessel 11 has a liquid phase section 11a on the lower side and a gas phase section 11b on the upper side, with the liquid level of the stored liquefied gas being interposed between them. The gas phase section 11b contains evaporated gas (hereinafter also referred to as "boil-off gas" or "BOG") that is formed when the liquefied gas is evaporated within the first pressure vessel 11 due to natural heat input.

[0014] A first liquid pipe 12 and a first gas pipe 13 are connected to the first pressure vessel 11. One end of the first liquid pipe 12 is disposed in a liquid phase section 11a within the first pressure vessel 11, and the other end of the first liquid pipe 12 is disposed outside the first pressure vessel 11. The other end of the first liquid pipe 12 is connectable to a first loading arm 22a, which will be described later. One end of the first gas pipe 13 is disposed in a gas phase section 11b within the first pressure vessel 11, and the other end of the first gas pipe 13 is disposed outside the first pressure vessel 11. The other end of the first gas pipe 13 is connectable to a second loading arm 23a, which will be described later.

[0015] In this embodiment, the onshore facility 2 is a liquefied gas receiving terminal. The onshore facility 2 receives liquefied gas from the liquefied gas carrier 1 via a loading and unloading system 3. The loading and unloading system 3 is equipped with a second pressure vessel 21. The second pressure vessel 21, which is the receiving side, also stores the same type of liquefied gas as that stored in the first pressure vessel 11, i.e., liquefied hydrogen in this example.

[0016] The second pressure vessel 21 is capable of storing liquefied gas under high pressure. The second pressure vessel 21 has a liquid phase 21a below the liquid level of the stored liquefied hydrogen and a gas phase 21b above it. The gas phase 21b contains boil-off gas, which is the liquefied gas vaporized within the second pressure vessel 21 due to natural heat input.

[0017] A second liquid pipe 22 is connected to the second pressure vessel 21. One end of the second liquid pipe 22 is connected to the second pressure vessel 21, and the other end of the second liquid pipe 22 is disposed outside the second pressure vessel 21. The second liquid pipe 22 includes a first loading arm 22a. The first loading arm 22a is disposed at the other end of the second liquid pipe 22.

[0018] The cargo handling system 3 also includes a gas storage tank 31, a compressor 32, a first BOG piping 33, and a second BOG piping 34. The gas storage tank 31 stores the same type of gas as the evaporated gas produced by vaporizing the liquefied gas stored in the first pressure vessel 11, i.e., hydrogen gas in this example, in a compressed state. In this embodiment, the gas stored in the gas storage tank 31 is gas introduced from the second pressure vessel 21. The first BOG piping 33 introduces the boil-off gas in the second pressure vessel 21 from the gas phase section 21b of the second pressure vessel 21 to the compressor 32, and the second BOG piping 34 introduces the gas compressed by the compressor 32 to the gas storage tank 31.

[0019] More specifically, one end 33a of the first BOG piping 33 is connected to the second pressure vessel 21, and the other end 33b of the first BOG piping 33 is connected to the compressor 32. An on-off valve 35 that opens and closes the first BOG piping 33 is disposed in the first BOG piping 33. A heater 36 is disposed in the first BOG piping 33 between the on-off valve 35 and the compressor 32. One end 34a of the second BOG piping 34 is connected to the compressor 32, and the other end 34b of the second BOG piping 34 is connected to the gas storage tank 31.

[0020] When the compressor 32 is operated while the on-off valve 35 is open, the boil-off gas in the second pressure vessel 21 is guided to the heater 36 through the first BOG piping 33. The gas heated by the heater 36 is compressed by the compressor 32. The gas compressed by the compressor 32 is guided to the gas storage tank 31 through the second BOG piping 34.

[0021] A second gas pipe 23 is connected to the gas storage tank 31. One end 23b of the second gas pipe 23 is connected to the gas storage tank 31. The other end of the second gas pipe 23 is connectable to the first gas pipe 13 extending from the first pressure vessel 11. Specifically, the second gas pipe 23 includes a second loading arm 23a. The second loading arm 23a is disposed at the other end of the second gas pipe 23. An on-off valve 24 that opens and closes the second gas pipe 23 is disposed in the second gas pipe 23. Furthermore, an on-off valve 25 is disposed in a portion of the second gas pipe 23 between the on-off valve 24 and the second loading arm 23a.

[0022] The cargo handling system 3 also includes a gas release facility 41. The gas release facility 41 releases the boil-off gas discharged from the second pressure vessel 21, for example, when the amount of gas stored in the gas storage tank 31 reaches the allowable storage amount. The gas release facility 41 is connected to a release pipe 42. The release pipe 42 branches off from a portion of the first BOG pipe 33 between the second pressure vessel 21 and the on-off valve 35. An on-off valve 43 is disposed in the release pipe 42. A heater 44 is disposed in a portion of the release pipe 42 between the on-off valve 43 and the gas release facility 41. When the on-off valve 43 is opened, the boil-off gas discharged from the second pressure vessel 21 is heated by the heater 44 and then released by the gas release facility 41. The boil-off gas discharged from the second pressure vessel 21 may be sent not only to the gas release facility 41 but also to, for example, a power generation facility or a facility that can utilize cold energy.

[0023] The cargo handling system 3 also includes a first connection pipe 51, a second connection pipe 61, and a third connection pipe 71 so that it can be used not only for unloading but also for loading.

[0024] The first connection pipe 51 connects the first BOG pipe 33 and the second gas pipe 23. Specifically, one end of the first connection pipe 51 is connected to a portion of the first BOG pipe 33 between the second pressure vessel 21 and the on-off valve 35, and the other end of the first connection pipe 51 is connected to a portion of the second gas pipe 23 between the on-off valve 24 and the on-off valve 25. An on-off valve 52 that opens and closes the first connection pipe 51 is arranged in the first connection pipe 51.

[0025] Further, the second connection pipe 61 connects the second gas pipe 23 and the discharge pipe 42. Specifically, one end of the second connection pipe 61 is connected to a portion of the second gas pipe 23 between the on-off valve 25 and the second loading arm 23a, and the other end of the second connection pipe 61 is connected to a portion of the discharge pipe 42 between the on-off valve 43 and the heater 44. An on-off valve 62 that opens and closes the second connection pipe 61 is arranged in the second connection pipe 61.

[0026] Furthermore, the third connection pipe 71 connects the second connection pipe 61 to the first BOG pipe 33. Specifically, one end of the third connection pipe 71 is connected to a portion between the end of the second connection pipe 61 connected to the second gas pipe 23 and the on-off valve 62, and the other end of the third connection pipe 71 is connected to a portion of the first BOG pipe 33 between the on-off valve 35 and the heater 36. An on-off valve 72 that opens and closes the third connection pipe 71 is arranged in the third connection pipe 71.

[0027] <Unloading method> Next, a method for unloading liquefied hydrogen using the cargo handling system 3 will be described.

[0028] (Storage process) The gas storage tank 31 stores compressed hydrogen gas, which is the same type of gas as the evaporated gas produced when the liquefied gas stored in the first pressure vessel 11 is vaporized. The compressed gas is stored in the gas storage tank 31, for example, before the liquefied gas carrier 1 arrives at port.

[0029] Specifically, the receiving second pressure vessel 21 has been storing liquefied hydrogen and has been in a cooled-down state since before receiving the liquefied hydrogen from the first pressure vessel 11. Inside the second pressure vessel 21, the liquefied hydrogen is vaporized, generating boil-off gas. This boil-off gas is compressed and stored in the gas storage tank 31. For example, the timing for directing the boil-off gas from the second pressure vessel 21 to the gas storage tank 31 is when the gas pressure inside the second pressure vessel 21 reaches or exceeds the set pressure set for the second pressure vessel 21.

[0030] When the on-off valve 35 is opened and the compressor 32 is operated while the on-off valves 24, 43, 52, and 72 are closed, the boil-off gas in the second pressure vessel 21 is guided to the heater 36 through the first BOG piping 33. The boil-off gas heated by the heater 36 is compressed by the compressor 32. The gas compressed by the compressor 32 is guided to the gas storage tank 31 through the second BOG piping 34.

[0031] Gas storage tank 31 stores hydrogen gas at a pressure high enough to push liquefied hydrogen out of first pressure vessel 11. The pressure in gas storage tank 31 is, for example, 250 kPa or higher, and preferably 300 kPa or higher.

[0032] (Connection process) Next, the first pressure vessel 11 and the second pressure vessel 21 are connected. Specifically, when the liquefied gas carrier 1 arrives at the port, the first loading arm 22a is operated to connect the first liquid piping 12 and the second liquid piping 22.

[0033] Furthermore, the first pressure vessel 11 is connected to the gas storage tank 31. Specifically, the second loading arm 23a is operated to connect the first gas pipe 13 to the second gas pipe 23. Note that the first pressure vessel 11 and the gas storage tank 31 may be connected before the first pressure vessel 11 and the second pressure vessel 21 are connected.

[0034] (Pressure process) Next, gas is supplied from the gas storage tank 31 to the gas phase section 11b in the first pressure vessel 11, thereby pressurizing the gas phase section 11b in the first pressure vessel 11. Due to the pressure difference between the pressure in the first pressure vessel 11 and the pressure in the second pressure vessel 21, liquefied gas is sent from the first pressure vessel 11 to the second pressure vessel 21.

[0035] Specifically, the on-off valves 24 and 25 are opened with the on-off valves 52, 62, and 72 closed. As a result, hydrogen gas is supplied from the gas storage tank 31 to the gas phase section 11b in the first pressure vessel 11 via the first gas piping 13 and the second gas piping 23 due to the pressure in the gas storage tank 31. As a result, the gas phase section 11b of the first pressure vessel 11 becomes high pressure, and liquefied hydrogen is sent from the first pressure vessel 11 to the second pressure vessel 21 via the first liquid piping 12 and the second liquid piping 22 due to the pressure in the gas phase section 11b in the first pressure vessel 11. Note that if the cargo handling system 3 does not include the first connecting piping 51, the second connecting piping 61, and the third connecting piping 71, it is not necessary to close the on-off valves 52, 62, and 72.

[0036] As described above, the cargo handling system 3 and cargo handling method according to this embodiment make it possible to use high-pressure gas stored in the gas storage tank 31 to send liquefied gas from the first pressure vessel 11 to the second pressure vessel 21. In other words, it is possible to handle liquefied gas without using a pump.

[0037] A cargo handling pump connected to one end of the first liquid piping 12 may be disposed in the liquid phase section 11a of the first pressure vessel 11. For example, cargo handling may be performed using the cargo handling pump under normal circumstances, and if a malfunction occurs in the cargo handling pump, cargo handling may be performed using the cargo handling method described in this embodiment.

[0038] The loading and unloading method of this embodiment can be used to load and unload various liquefied gases, but is suitable for loading and unloading liquefied hydrogen. 3 ) is lower than the density of other liquefied gases such as liquefied natural gas. Therefore, the pressure of the gas phase 11b required to deliver liquefied hydrogen from the first pressure vessel 11 to the second pressure vessel 21 is lower than the pressure of the gas phase required to deliver other types of liquefied gas. Therefore, when the loading and unloading method according to this embodiment is used to load and unload liquefied hydrogen, the conditions imposed on the compressed gas stored in the gas storage tank 31 can be relaxed.

[0039] In this embodiment, the first pressure vessel 11 is installed on the liquefied gas carrier 1, and the second pressure vessel 21 and the gas storage tank 31 are installed on the land facility 2. Therefore, there is no need to secure space on the liquefied gas carrier 1 to install the gas storage tank 31.

[0040] Furthermore, in this embodiment, the boil-off gas in the second pressure vessel 21 is stored in the gas storage tank 31. Therefore, the boil-off gas generated in the second pressure vessel 21 can be effectively utilized for cargo handling.

[0041] <Loading method> As described above, the loading system 3 of this embodiment can also be applied to loading for supplying liquefied gas. A method for loading liquefied hydrogen using the loading system 3 will be described. In the following description of the loading method, for convenience, the second pressure vessel 21 of the onshore facility 2 will be referred to as the "first pressure vessel 21," and the first pressure vessel 11 of the liquefied gas carrier 1 will be referred to as the "second pressure vessel 11." In other words, a loading method for supplying liquefied gas from the first pressure vessel 21 of the onshore facility 2 to the second pressure vessel 11 of the liquefied gas carrier 1 will be described.

[0042] (Storage process) The gas storage tank 31 stores compressed hydrogen gas, which is the same type of gas as the evaporated gas produced by the liquefied gas stored in the second pressure vessel 11 of the liquefied gas carrier 1. The storage of compressed gas in the gas storage tank 31 is carried out, for example, before the liquefied gas carrier 1 arrives at port.

[0043] (Connection process) Next, the first pressure vessel 21 and the second pressure vessel 11 are connected. Specifically, when the liquefied gas carrier 1 arrives at the port, the first loading arm 22a is operated to connect the first liquid piping 12 and the second liquid piping 22.

[0044] Also, the second pressure vessel 11 is connected to the discharge equipment 41. Specifically, the second loading arm 23a is operated to connect the first gas pipe 13 to the second gas pipe 23 with the on-off valves 25, 62, and 72 closed. Note that either the connection work using the first loading arm 22a or the connection work using the second loading arm 23a may be performed first.

[0045] (Pressure process) Next, gas is supplied from the gas storage tank 31 to the gas phase section 21b in the first pressure vessel 21, thereby pressurizing the gas phase section 21b in the first pressure vessel 21. Due to the pressure difference between the pressure in the first pressure vessel 21 and the pressure in the second pressure vessel 11, liquefied gas is sent from the first pressure vessel 21 to the second pressure vessel 11.

[0046] Specifically, the on-off valves 24 and 52 are opened while the on-off valves 25, 35, and 43 are closed. As a result, hydrogen gas is supplied from the gas storage tank 31 to the gas phase section 21b in the first pressure vessel 21 via the first gas piping 13, the first connection piping 51, and the first BOG piping 33 due to the pressure in the gas storage tank 31. As a result, the gas phase section 21b of the first pressure vessel 21 becomes high pressure, and liquefied hydrogen is sent from the first pressure vessel 21 to the second pressure vessel 11 via the first liquid piping 12 and the second liquid piping 22 due to the pressure in the gas phase section 21b in the first pressure vessel 21.

[0047] Furthermore, by opening the on-off valve 62, the boil-off gas discharged from the second pressure vessel 11 by the gas discharge equipment 41 is discharged.

[0048] As described above, the cargo handling system 3 and cargo handling method according to this embodiment can use the high-pressure gas stored in the gas storage tank 31 to send liquefied gas from the first pressure vessel 21 to the second pressure vessel 11. In other words, the liquefied gas can be loaded without using a pump.

[0049] In addition, in the storage step of the loading method, the boil-off gas in the second pressure vessel 11 of the liquefied gas carrier 1 may be stored in the gas storage tank 31. Specifically, for example, after the liquefied gas carrier 1 arrives at port, the second loading arm 23a is operated to connect the first gas pipe 13 and the second gas pipe 23 with the on-off valves 25, 35, 62, and 72 closed. Thereafter, the on-off valve 72 is opened and the compressor 32 is operated, whereby the boil-off gas in the second pressure vessel 11 is guided to the heater 36 through the first gas pipe 13, the second gas pipe 23, the second connecting pipe 61, and the third connecting pipe 71, and then through the first BOG pipe 33. In this case, the portion corresponding to the boil-off gas path from the second pressure vessel 11 to the compressor 32 constitutes the first BOG pipe, which guides the evaporated gas, formed by the vaporization of the liquefied gas in the second pressure vessel 11, from the gas phase portion 11b of the second pressure vessel 11 to the compressor 32. The boil-off gas heated by the heater 36 is compressed by the compressor 32. The gas compressed by the compressor 32 is led to the gas storage tank 31 through the second BOG piping 34. In this case, in the connection process, only the first pressure vessel 21 and the second pressure vessel 11 are connected.

[0050] <Other embodiments> The present disclosure is not limited to the above-described embodiments, and the configurations thereof can be changed, added, or deleted.

[0051] For example, although the cargo handling system 3 described in the above embodiment is configured to be usable for both unloading and loading, the cargo handling system may be configured to be usable for only one of unloading and loading. For example, if the cargo handling system is configured to be usable only for unloading, the cargo handling system may not include the first connection pipe 51, the second connection pipe 61, the third connection pipe 71, the on-off valve 25, etc. Conversely, if the cargo handling system is configured to be usable only for loading, the cargo handling system may not include components, piping sections, on-off valves, etc. that are used only for unloading.

[0052] The first pressure vessel 11 does not have to be installed on the liquefied gas carrier 1, but may be installed on the land facility 2. Furthermore, the second pressure vessel 21 does not have to be installed on the land facility, but may be installed on the hull. The first pressure vessel 11 and the second pressure vessel 21 may be installed on different ships.

[0053] In the above embodiment, the pressure within the gas storage tank 31 is described as, for example, 250 kPa or higher, preferably 300 kPa or higher, but the pressure range of the gas stored in the gas storage tank 31 is not limited to this. The pressure within the gas storage tank need only be high enough to push liquefied hydrogen from the first pressure vessel to the second pressure vessel when the gas storage tank and the first pressure vessel are connected to allow gas to flow between them. The volume and pressure of the gas storage tank can be set appropriately depending on the volumes of the first and second pressure vessels, the density of the liquefied gas to be loaded, the positional relationship between the first and second pressure vessels, etc.

[0054] In the above embodiment, the BOG generated in the second pressure vessel 21 is stored in a compressed state in the gas storage tank 31, but the gas supply source for supplying gas to the gas storage tank does not have to be the second pressure vessel, and may be another container or facility. The gas storage tank only needs to store, in a compressed state, evaporated gas produced by vaporizing the same type of liquefied gas as the liquefied gas stored in the first pressure vessel.

[0055] A liquefied gas loading method according to one aspect of the present disclosure includes storing a compressed gas of the same type as the evaporated gas produced by vaporizing the liquefied gas stored in a first pressure vessel in a gas storage tank, connecting the first pressure vessel to a second pressure vessel, and supplying the gas from the gas storage tank to a gas phase in the first pressure vessel using the pressure in the gas storage tank, thereby delivering the liquefied gas from the first pressure vessel to the second pressure vessel. This method allows the liquefied gas to be delivered from the first pressure vessel to the second pressure vessel using the high-pressure gas stored in the gas storage tank. In other words, the liquefied gas can be loaded and unloaded without using a pump.

[0056] In the above method, for example, the liquefied gas is liquefied hydrogen. Since the density of liquefied hydrogen is lower than the density of other liquefied gases such as liquefied natural gas, the gas phase pressure required to deliver liquefied hydrogen from the first pressure vessel to the second pressure vessel is lower than the gas phase pressure required to deliver other liquefied gases. For this reason, the above method is suitable for loading and unloading liquefied hydrogen.

[0057] In the above method, the first pressure vessel may be installed on a ship, and the second pressure vessel and the gas storage tank may be installed on land, and the loading / unloading method may further include connecting the first pressure vessel and the gas storage tank before supplying the gas from the gas storage tank to the gas phase in the first pressure vessel. Because the gas storage tank is installed on land, there is no need to secure space for installing the gas storage tank on the ship.

[0058] In the above method, the second pressure vessel may store the same type of liquefied gas as the liquefied gas stored in the first pressure vessel before delivering the liquefied gas from the first pressure vessel to the second pressure vessel, and storing the compressed gas in the gas storage tank may include compressing the evaporated gas produced by evaporation of the liquefied gas in the second pressure vessel and storing it in the gas storage tank. Typically, the receiving second pressure vessel is in a cooled-down state where liquefied gas has been stored therein before receiving the liquefied gas from the first pressure vessel. According to the above method, by storing the boil-off gas in the gas storage tank in the second pressure vessel where liquefied gas has been stored before loading / unloading, the boil-off gas can be effectively utilized in loading / unloading.

[0059] A liquefied gas loading system according to one embodiment of the present disclosure is a liquefied gas loading system for supplying liquefied gas from a first pressure vessel containing liquefied gas to a second pressure vessel, the system comprising: a gas storage tank for storing compressed gas of the same type as the evaporated gas produced by the liquefied gas stored in the first pressure vessel; a gas pipe connected to the gas storage tank at one end and connected or connectable to a pipe extending from the first pressure vessel at the other end; and an on-off valve for opening and closing the gas pipe. When the on-off valve transitions from a closed state to an open state while the first pressure vessel and the second pressure vessel are connected, the gas storage tank supplies the gas to a gas phase within the first pressure vessel through the gas pipe, thereby delivering the liquefied gas from the first pressure vessel to the second pressure vessel. This configuration allows the liquefied gas to be delivered from the first pressure vessel to the second pressure vessel using high-pressure gas stored in the gas storage tank. This means that the liquefied gas can be loaded and unloaded without using a pump.

[0060] The liquefied gas handling system may further include a compressor, a first BOG piping that guides evaporated gas generated by vaporization of the liquefied gas in the second pressure vessel from the gas phase of the second pressure vessel to the compressor, and a second BOG piping that guides gas compressed by the compressor to the gas storage tank. According to this configuration, the boil-off gas in the second pressure vessel in which the liquefied gas is stored before loading and unloading can be stored in the gas storage tank, thereby making it possible to effectively utilize the boil-off gas for loading and unloading. [Explanation of symbols]

[0061] 1: Liquefied gas carrier 2: Land facilities 3: Cargo handling system 10: Hull 11: First pressure vessel 11a:Liquid phase part 11b: Gas phase part 12: First liquid piping 13: First gas pipe 21: Second pressure vessel 21a:Liquid phase part 21b: Gas phase part 22: Second liquid piping 23: Second gas pipe 24: On-off valve 31:Air storage tank 32: Compressor 33: First BOG piping 34: Second BOG piping

Claims

1. The liquefied gas stored in the first pressure vessel is evaporated into a gas of the same type as the evaporated gas, and the gas is compressed and stored in the gas storage tank; connecting the first pressure vessel and the second pressure vessel; A method for loading and unloading liquefied gas, comprising: supplying the gas from the gas storage tank to a gas phase portion in the first pressure vessel using the pressure in the gas storage tank; and delivering the liquefied gas from the first pressure vessel to the second pressure vessel.

2. 2. The method for loading and unloading liquefied gas according to claim 1, wherein the liquefied gas is liquefied hydrogen.

3. the first pressure vessel is installed on a ship, and the second pressure vessel and the air storage tank are installed on land; 3. The method for loading and unloading liquefied gas described in claim 1 or 2, further comprising connecting the first pressure vessel and the gas storage tank before supplying the gas from the gas storage tank to the gas phase portion in the first pressure vessel.

4. Before the liquefied gas is delivered from the first pressure vessel to the second pressure vessel, the second pressure vessel stores the same type of liquefied gas as the liquefied gas stored in the first pressure vessel; 4. A method for loading and unloading liquefied gas according to claim 1, wherein storing the gas in the gas storage tank in a compressed state includes compressing evaporated gas formed by evaporation of liquefied gas in the second pressure vessel and storing the evaporated gas in the gas storage tank.

5. A liquefied gas loading and unloading system for supplying liquefied gas from a first pressure vessel storing liquefied gas to a second pressure vessel, comprising: a gas storage tank for storing, in a compressed state, the same type of gas as the evaporated gas obtained by vaporizing the liquefied gas stored in the first pressure vessel; a gas pipe having one end connected to the gas storage tank and the other end connected or connectable to a pipe extending from the first pressure vessel; an on-off valve that opens and closes the gas pipe, A liquefied gas loading and unloading system in which, when the first pressure vessel and the second pressure vessel are connected and the on-off valve transitions from a closed state to an open state, the gas storage tank supplies the gas to a gas phase portion in the first pressure vessel using the pressure in the gas storage tank, thereby sending liquefied gas from the first pressure vessel to the second pressure vessel.

6. A compressor; a first BOG pipe that guides evaporated gas generated by vaporization of the liquefied gas in the second pressure vessel from a gas phase portion of the second pressure vessel to the compressor; The liquefied gas handling system according to claim 5, further comprising: a second BOG pipe that guides the gas compressed by the compressor to the gas storage tank.

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