TW202240097A - Suppression device and suppression method - Google Patents

Abstract

To provide a suppression device and a suppression method with which BOG generation can be suppressed when a low-temperature liquefied gas is received. This suppression device 1 has: a refrigerator 30 disposed in a path 10 which connects a cargo tank T1 and a storage tank T2; and a pump 40 which is provided inside the storage tank and can feed, toward the refrigerator, a liquid heel inside the storage tank.

Description

Suppression device and suppression method

The invention relates to a suppression device and a suppression method for suppressing the occurrence of BOG.

Low-temperature liquefied gas (hereinafter also referred to as liquefied gas) such as liquefied natural gas or liquid hydrogen is heated by heat input from the outside of the storage tank, thereby generating BOG (boil-off gas). Accompanied by the occurrence of this BOG, the pressure in the storage tank increases.

In addition, when receiving liquefied gas from the cargo tank (cargo tank) as the loaded cargo to the storage tank, the received liquefied gas is caused by the heat input of the cargo pumps or the receiving piping, and it is different from the non-receiving time. In comparison, the occurrence of BOG will increase. Among them, the liquefied gas received from the cargo tank is called cargo liquid, and the liquefied gas stored in the storage tank is called heel liquid.

In connection with this, a treatment method for reliquefying generated BOG has been conventionally known (for example, Patent Document 1 described below). prior art literature patent documents

Patent Document 1: Japanese Patent Application Laid-Open No. H10-19199

[Problem to be Solved by the Invention]

In general, the reliquefaction system used to reliquefy BOG is to boost the pressure with a compressor, then cool it with a heat exchanger to liquefy it, or inject BOG into the liquefied gas sent out to liquefy it, and then pressurize it with a pump. The method to send. However, in this system, since the system is relatively complicated, a decrease in reliability, an increase in size of the device, and the like become issues.

In addition, when BOG of liquefied gas is reliquefied in a refrigerator, since an extremely low cooling temperature is required, thermal efficiency decreases. Therefore, there is a problem of increasing power to operate the refrigerator. In addition, when the BOG of the sent liquefied gas is injected, the flow rate of the BOG that can be liquefied at the flow rate of the sent liquefied gas is limited. There is a problem that BOG cannot be reliquefied without the liquefied gas being sent.

Based on the above, a method for suppressing the generation of BOG rather than reliquefying the generated BOG is sought.

The present invention was made to solve the above-mentioned problems, and an object of the present invention is to provide a suppressing device and a suppressing method capable of suppressing the generation of BOG. [Means to solve the problem]

The suppressing device of the present invention which achieves the above-mentioned object is a suppressing device for suppressing BOG generated when cargo liquid is received from a cargo tank to a storage tank. The suppressing device includes: a refrigerator disposed on a path connecting the cargo tank and the storage tank; and a pump provided in the storage tank and capable of sending excess liquid in the storage tank toward the refrigerator.

In addition, the suppressing method of the present invention that achieves the above object is a suppressing method for suppressing BOG that occurs when cargo liquid is received from a cargo tank toward a storage tank by a suppressing device, the suppressing device having a refrigerator disposed in the cargo tank and between paths connected to the storage tank; and a pump provided inside the storage tank to transport the residual liquid in the storage tank toward the refrigerator. The suppressing method has the following steps: when the cargo liquid is received into the storage tank, the cargo liquid is cooled to a supercooled state by the refrigerator; and the cooled cargo liquid is transported to the storage tank. [Effect of Invention]

With the suppression device and suppression method described above, when the cargo liquid is received from the cargo tank toward the storage tank, the cargo liquid or the residual liquid or both are sent to the Storage tank, so it can reduce the occurrence of BOG when receiving.

＜First Embodiment＞ A first embodiment of the present invention will be described while referring to FIG. 1 and FIG. 2 . However, in the description of the drawings, the same reference numerals are assigned to the same elements, and overlapping descriptions are omitted. The dimensional ratios in the drawings are exaggerated for convenience of explanation, and may be different from actual ratios.

Fig. 1 is a schematic plan view showing a suppression device 1 according to a first embodiment of the present invention. FIG. 2 is a diagram for explaining a supercooled state, and a diagram showing a state diagram.

The suppression device 1 of the first embodiment is a device for suppressing BOG generated when receiving liquefied gas from the cargo tank T1 to the storage tank T2. Here, it is not particularly limited to liquefied gas, and examples thereof include LNG (liquefied natural gas), LPG (liquefied petroleum gas), liquid hydrogen, and liquid nitrogen.

As shown in FIG. 1 , the suppression device 1 has: a first path (equivalent to a path) 10 connecting the cargo tank T1 and the storage tank T2; a bypass path 20 branched from the first path 10; The refrigerator 30 in the first path 10; the pump 40 provided in the storage tank T2; the second path 50 connecting the pump 40 and the first path 10; branching from the second path 50 to separate the storage tank T2 The third path 60 for sending the liquefied gas inside to the outside; the measuring unit 70 for measuring the temperature of the liquefied gas at three places in the height direction in the storage tank T2; and the control unit (not shown) for controlling the operation of the refrigerator 30.

Liquid cargo tank T1 is the cargo loaded with liquid cargo. The cargo tank T1 is, for example, the loaded cargo of a ship. The residual liquid which is a raffinate is stored in the storage tank T2. The cargo liquid in the cargo tank T1 is sent to the storage tank T2 via the first path 10 at a predetermined timing.

As shown in FIG. 1 , a first valve 11 and a confluence portion 12 are arranged on the first path 10 . The first valve 11 is arranged on the cargo tank T1 side with respect to the confluence portion 12 . The first valve 11 can control the amount of liquefied gas sent from the cargo tank T1 to the storage tank T2. The first path 10 is piping.

The confluence portion 12 is arranged in the refrigerator 30 of the first valve 11 . The confluence portion 12 mixes the liquefied gas from the cargo tank T1 and the liquefied gas from the storage tank T2 , and is arranged so that the mixed liquefied gas is sent back to the storage tank T2 via the refrigerator 30 .

In this embodiment, as shown in FIG. 1 , it is preferable that the end 10A of the storage tank T2 side of the first path 10 is located near the center of the storage tank T2.

The bypass path 20 branches off from the first path 10 . As shown in FIG. 1 , a bypass valve 21 is disposed on the bypass path 20 . The bypass valve 21 can adjust the amount of the liquefied gas flowing in the confluence part 12 to the bypass path 20 . By providing the bypass path 20 as described above, the cargo liquid from the cargo tank T1 can pass through the bypass path 20 . Therefore, if the cargo liquid is sufficiently cooled to a supercooled state, it is not necessary to pass through the first path 10 cooled by the refrigerator 30 .

The refrigerator 30 makes the cargo liquid received from the cargo tank T1 and/or the residual liquid transferred from the storage tank T2 by the pump 40 into a supercooled state. The supercooled state will be described below with reference to the state diagram of FIG. 2 .

The liquefied gas is usually in a saturated state at the boundary between the liquid phase and the gas phase indicated by a black circle in FIG. 2 . By cooling the liquefied gas in this saturated state with the refrigerator 30, it moves from the black circle to the left white circle, and becomes a supercooled state. Since the liquefied gas in a supercooled state is completely in a liquid state, generation of BOG can be suppressed.

The refrigerator 30 is not particularly limited as long as it can cool the liquefied gas to a supercooled state. For example, a refrigerator 30 of a reverse Brayton cycle or a Stirling cycle can be used. . The refrigerator 30 can be formed at -165°C to -162°C by, for example, cooling liquefied gas in a saturated state at -160°C.

As shown in FIG. 1, the pump 40 is provided near the bottom of the storage tank T2. The pump 40 is provided to send the residual liquid in the storage tank T2 to the outside through the third path 60 . In addition, the pump 40 is provided to return the liquefied gas in the storage tank T2 to the confluence part 12 through the second path 50 so as to mix it with the cargo liquid from the cargo tank T1. As the pump 40, well-known ones can be used.

The second path 50 connects the pump 40 and the first path 10 . As shown in FIG. 1 , a second valve 51 is arranged on the second path 50 . The second valve 51 can control the amount of the surplus liquid sent from the storage tank T2 by the pump 40 to the confluence part 12 side. The second path 50 is piping.

The third path 60 is a path for sending the residual liquid in the storage tank T2 to the outside. As shown in FIG. 1 , a third valve 61 is arranged on the third path 60 . The third valve 61 can control the amount of the excess liquid sent from the storage tank T2 by the pump 40 to the outside. The third path 60 is piping.

As shown in FIG. 1, the measuring part 70 measures the temperature in the three places P1, P2, and P3 of the height direction in the storage tank T2. However, the measurement locations in the height direction are not limited to three locations, and two or more locations may be sufficient. As the measuring unit 70, a known thermometer can be used. However, the measuring unit 70 may measure the height of the place where the temperature is measured in addition to the temperature.

The control unit controls the opening and closing of the first valve 11 , the bypass valve 21 , the second valve 51 , and the third valve 61 . The control unit controls the drive of the pump 40 . The control unit controls the operation of the refrigerator 30 based on the temperature measured by the measurement unit 70 . The control unit is, for example, a CPU.

Next, the suppressing method of the suppressing device 1 according to the first embodiment will be described with reference to FIGS. 3 to 5 . Fig. 3 is a diagram for explaining a suppression method of one of the suppression device 1 according to the first embodiment. Fig. 4 is a diagram for explaining the second suppressing method of the suppressing device 1 according to the first embodiment. Fig. 5 is a diagram for explaining the third suppressing method of the suppressing device 1 of the first embodiment.

First, with reference to FIG. 3 , the suppressing method of one of the suppressing devices 1 according to the first embodiment will be described. One suppression method is the suppression method when receiving liquefied gas, which is characterized in that the residual liquid in the storage tank T2 is mixed with the cargo liquid from the liquid cargo tank T1, and the mixed liquefied gas is cooled by the refrigerator 30 to form a superfluous gas. cold state. In FIG. 3 , the paths through which the liquefied gas passes are indicated by thick lines.

First, the controller drives the pump 40 to send the residual liquid in the storage tank T2 to the confluence part 12 . On the other hand, the control part opens the 1st valve 11, and the cargo liquid from the cargo tank T1 is sent to the confluence part 12. Next, in the confluence part 12 , the residual liquid originally located in the storage tank T2 and the cargo liquid from the cargo tank T1 are mixed and sent to the refrigerator 30 . The mixed liquefied gas is cooled to a supercooled state in the refrigerator 30 and sent to the storage tank T2. However, the third valve 61 may be in an open state or a closed state.

Here, for example, if the liquefied gas that has not been cooled by the refrigerator 30 is transported into the storage tank T2, the liquefied gas is vaporized at the time of receiving due to the heat input from the liquid cargo pump or the receiving piping, thereby generating a large amount of BOG.

On the other hand, according to one suppression method, the mixed liquefied gas is cooled to a supercooled state and transported into the storage tank T2, so the generation of BOG can be appropriately suppressed.

Next, referring to FIG. 4 , the suppressing method of the suppressing device 1 of the first embodiment will be described. The second suppressing method is a suppressing method when receiving liquefied gas, which is characterized in that only the remaining liquid from the cargo tank T1 is cooled by the refrigerator 30 to form a supercooled state. In FIG. 4 , the paths through which the residual liquid and cargo liquid pass are indicated by thick lines.

First, the controller opens the first valve 11 to send the cargo liquid from the cargo tank T1 to the refrigerator 30 through the confluence part 12 . The cargo liquid from the liquid cargo tank T1 is cooled to a supercooled state by the refrigerator 30, and then is sent to the storage tank T2. However, the third valve 61 may be in an open state or a closed state.

As mentioned above, through the second suppression method, the cargo liquid from the cargo tank T1 is cooled to a supercooled state and transported to the storage tank T2, so the occurrence of BOG can be appropriately suppressed.

Next, referring to FIG. 5 , the third suppressing method of the suppressing device 1 of the first embodiment will be described. The third suppression method is a suppression method at a steady state (non-receiving time), which is characterized in that only the residual liquid originally in the storage tank T2 is cooled by the refrigerator 30 to form a supercooled state. In FIG. 5 , paths through which the residual liquid and cargo liquid pass are indicated by thick lines.

First, the controller drives the pump 40 to send the liquefied gas in the storage tank T2 to the confluence part 12 . Next, the residual liquid originally located in the storage tank T2 is sent to the refrigerator 30, cooled to a supercooled state in the refrigerator 30, and then sent to the storage tank T2. However, the third valve 61 may be in an open state or a closed state.

At this time, the measuring unit 70 measures the temperature of the liquefied gas at three positions P1, P2, and P3 in the height direction in the storage tank T2 and the height of the place where the temperature is measured, to confirm whether the liquefied gas has been cooled to a supercooled state.

When the temperature in the storage tank T2 is measured by the measuring part 70, if the remaining liquid is indeed cooled to a supercooled state, the control part preferably shuts down the operation of the refrigerator 30. Next, when the temperature in the storage tank T2 is measured by the measuring part 70, if the temperature rises and the residual liquid is close to a saturated state, the control part preferably turns on the operation of the refrigerator 30. As described above, by controlling the operation of the refrigerator 30 by the controller, it becomes unnecessary to operate the refrigerator 30 constantly, and the operation efficiency of the refrigerator 30 is improved.

However, it is also possible to control the operation of the refrigerating machine 30 as follows, differently from the above-mentioned usage method. That is, the refrigerating machine 30 is turned on using surplus electric power to surely cool the liquefied gas to a supercooled state. Next, when the electricity is insufficient, the refrigerator 30 is turned off. By using it as described above, variable renewable energy (solar power generation or wind power generation) can be effectively utilized.

Next, the fourth suppressing method of the suppressing device 1 of the first embodiment will be described. In this case, the target liquefied gas is LNG. The fourth suppression method is a suppression method for suppressing the occurrence of stratification when a cargo liquid having a density different from that of the residual liquid in the storage tank T2 is received.

First, a case where the cargo liquid from the cargo tank T1 is heavier than the remaining liquid in the storage tank T2 will be described.

Before the control unit receives the cargo liquid from the liquid cargo tank T1, it cools the remaining liquid in the storage tank T2 by the refrigerator 30 to increase the supercooling degree in the same way as the above-mentioned third suppression method.

Next, the cargo liquid is received from the cargo tank T1. At this time, the density of the remaining liquid in the storage tank T2 increases due to the increased subcooling, and can be made approximately the same as the density of the cargo liquid from the cargo tank T1. Therefore, stratification of the liquefied gas in the storage tank T2 can be suitably suppressed.

Here, the density of the residual liquid in the storage tank T2 and the cargo liquid from the cargo tank T1 may be substantially the same, or not completely the same, and may be within the range of a density difference that is not stratified in the storage tank T2.

Next, a case where the cargo liquid from the cargo tank T1 is lighter than the remaining liquid in the storage tank T2 will be described.

The control part is the same as the suppression method of the above-mentioned two, and the cargo liquid from the liquid cargo tank T1 is cooled by the refrigerator 30 to increase the degree of subcooling, and then sent to the storage tank T2. At this time, the density of the cargo liquid from the cargo tank T1 increases due to the increase in the subcooling degree, and can be made approximately the same as the density of the remaining liquid in the storage tank T2. Therefore, stratification of the liquefied gas can be appropriately suppressed.

As described above, the suppressing device 1 of the first embodiment is a suppressing device 1 for suppressing BOG generated when the cargo liquid is received from the cargo tank T1 to the storage tank T2. The suppression device 1 has: a refrigerator 30 disposed on the first path 10 connecting the cargo tank T1 and the storage tank T2; pump 40. With the suppressing device 1 configured as above, when the cargo liquid is received from the cargo tank T1 to the storage tank T2, the cargo liquid or residual liquid or Since both are sent to the storage tank T2, the generation|occurrence|production of BOG at the time of reception can be reduced.

In addition, the suppressing device 1 further includes a bypass path 20 provided so as to branch off from the first path 10 connecting the cargo tank T1 and the storage tank T2. With the suppression device 1 configured as described above, the liquefied gas from the cargo tank T1 can pass through the bypass path 20 . Therefore, if the cargo liquid or the residual liquid or both are sufficiently cooled to a supercooled state, it is not necessary to pass through the first path 10 cooled by the refrigerator 30 .

Moreover, the suppressing apparatus 1 further has the measuring part 70 which measures the temperature of three places P1, P2, and P3 in the height direction in the storage tank T2. With the suppressing device 1 configured as above, it is possible to check whether the residual liquid is cooled to a supercooled state by measuring the temperature in the storage tank T2 by the measuring unit 70 . Next, if the excess liquid is surely cooled to a supercooled state, the control unit shuts off the operation of the refrigerator 30 . Next, the control unit turns on the operation of the refrigerating machine 30 when the remaining liquid is close to the saturated state. Therefore, it is not necessary to always turn on the refrigerator 30, and the operating efficiency of the refrigerator 30 is improved.

＜Second Embodiment＞ Next, referring to FIG. 6, the structure of the suppressing device 2 according to the second embodiment of the present invention will be described. However, the same reference numerals are assigned to the same components as those in the first embodiment, and description thereof will be omitted. Fig. 6 is a schematic diagram showing a suppression device 2 according to a second embodiment of the present invention. The suppression device 2 of the second embodiment is different from the configuration of the suppression device 1 of the first embodiment in the configuration of the first path 110 .

As shown in FIG. 6, the suppressing device 2 of the second embodiment has: a first path (corresponding to a path) 110 connecting the cargo tank T1 and the storage tank T2; a refrigerator 30 disposed on the first path 110; The pump 40 in the storage tank T2; the second path 50 connecting the pump 40 and the first path 10; the third path 60 branched from the second path 50 to send the remaining liquid in the storage tank T2 to the outside ; a measuring unit (not shown) that measures the temperature of the residual liquid at three places in the storage tank T2; and a control unit that controls the operation of the refrigerator 30. In this case, the target liquefied gas is LNG.

As shown in FIG. 6, the first path 110 has: an upper path 111 for conveying the excess liquid cooled by the refrigerator 30 on the upper side of the storage tank T2; The lower path 112 of the remaining liquid cooled by the machine 30 .

Adjustment valves 113 and 114 for adjusting the amount sent to the storage tank T2 are respectively provided in the upper path 111 and the lower path 112 .

Next, referring to FIG. 7 , the suppressing method of one of the suppressing devices 2 according to the second embodiment will be described. The suppressing method of the suppressing device 2 of the second embodiment is a suppressing method for suppressing occurrence of a roll-over phenomenon when the remaining liquid is stratified in the storage tank T2. In FIG. 7 , the routes through which the residual liquid and the cargo liquid pass are indicated by thick lines.

Here, the "tumbling phenomenon" means that in the layered storage tank T2, convection occurs inside each layer due to heat input from the outside, and material transfer and heat transfer progress without passing through the layer boundary, The density difference between the upper and lower layers gradually decreases, and after a certain period of time, the densities of the upper and lower layers become equal. When the boundary between the upper and lower layers is eliminated, the heat originally accumulated in the lower layer is released in a short period of time in the form of a large amount of BOG.

First, the controller drives the pump 40 to send the liquefied gas in the storage tank T2 to the confluence part 12 . Next, the residual liquid originally located in the storage tank T2 is sent to the refrigerator 30, and is cooled to a supercooled state in the refrigerator 30. The flow rate of the liquefied gas cooled to a supercooled state by the refrigerator 30 is adjusted by the adjustment valves 113 and 114, and is sent back to the residual liquid in the upper layer and the lower layer in the storage tank T2 through the upper path 111 and the lower path 112. the remaining liquid. However, the third valve 61 may be in an open state or a closed state.

In addition, the upper path 111 may be replaced with a top feeding pipe as an upper receiving pipe. Likewise, the lower path 112 can also be replaced with a bottom feeding pipe or a jet mixing nozzle as a lower receiving pipe.

Thereby, occurrence of BOG from the residual liquid in the upper layer can be suppressed, and an increase in density can be prevented. On the other hand, in the raffinate in the lower layer, the decrease in density can be suppressed by suppressing the increase in liquid temperature of the raffinate due to heat input with the cargo liquid in a supercooled state or the raffinate, or both. Therefore, it is possible to appropriately prevent the occurrence of the rolling phenomenon caused by the densities of the layered upper layer and the lower layer becoming equal.

＜Third Embodiment＞ Next, referring to FIG. 8, the structure of the suppressing device 3 according to the third embodiment of the present invention will be described. However, the same reference numerals are assigned to the same components as those in the first embodiment, and description thereof will be omitted. Fig. 8 is a schematic diagram showing a suppression device 3 according to a third embodiment of the present invention. The suppression device 3 of the third embodiment is different from the configuration of the suppression device 1 of the first embodiment in that a plurality of storage tanks T2 are provided.

In the suppressing device 3 of the third embodiment, as shown in FIG. 8 , three storage tanks T2 are provided.

Among the three storage tanks T2 , the residual liquid in one storage tank T21 is cooled to a supercooled state by the refrigerator 30 . Specifically, it is preferable to use surplus power to turn on the refrigerator 30 to surely cool the remaining liquid in a storage tank T21 to a supercooled state.

Next, by the pump 40, the residual liquid in one storage tank T21 formed in a subcooled state is sent to the receiving pipes of the cargo liquid of the other storage tanks T22 and T23 as shown in FIG. 8 . Thereby, generation|occurrence|production of BOG at the time of receiving in other storage tank T22, T23 can be suppressed.

By constituting the suppressing device 3 as described above, it is possible to store the supercooled excess liquid in one storage tank T21, thereby making it possible to store electricity as the supercooled excess liquid from renewable energy power. storage system to function.

However, the present invention is not limited to the above-mentioned embodiments, and various changes can be made within the scope of the patent application.

For example, in the first embodiment described above, the suppression device 1 has the bypass path 20 . However, the bypass path may not be provided in the suppression device.

In addition, in the above-mentioned embodiment, the suppression apparatuses 1 and 2 are provided with the measuring part 70, and the measuring part 70 measures the temperature of three places P1, P2, P3 in the height direction in the storage tank T2. However, the measuring unit may be configured to continuously measure the temperature in the height direction in the storage tank T2, and the height and density of the place where the temperature is measured.

In addition, in the above-mentioned second embodiment, the first path 110 has the upper path 111 and the lower path 112 . However, the first path may be only the upper path 111 or only the lower path 112 . With this configuration, although it is difficult to prevent the occurrence of the rolling phenomenon, the time until the rolling phenomenon occurs can be extended. During this period, the remaining liquid in the lower layer is driven off by the pump 40, and the lower layer can be made stratified by disappearing. wipe out.

In addition, in the above-mentioned third embodiment, the occurrence of BOG at the time of receiving the cargo liquid from the cargo tank T1 was suppressed. However, the present invention is not limited to this, and as shown in FIG. 9 , it can also be applied to suppress the occurrence of BOG in a steady state (non-reception state).

This application is based on Japanese Patent Application No. 2021-055279 filed on March 29, 2021, the disclosure of which is incorporated by reference in its entirety.

1,2: suppression device 10,110: 1st path 10A: end 11: 1st valve 12: Confluence Department 20: Bypass path 21: Bypass valve 30: Freezer 40: pump 50: 2nd path 51: 2nd valve 60: 3rd path 61: 3rd valve 70: Determination Department 111: Upper path 112: The lower path 113: Adjusting valve 114: Adjusting valve T1: cargo tank T2, T21, T22, T23: storage slots P1, P2, P3: parts

Fig. 1 is a schematic diagram showing a suppression device according to a first embodiment of the present invention. FIG. 2 is a diagram for explaining a subcooled state, and a diagram showing a state diagram. Fig. 3 is a diagram for explaining a suppressing method of one of the suppressing devices of the first embodiment. Fig. 4 is a diagram for explaining a second suppressing method of the suppressing device of the first embodiment. Fig. 5 is a diagram for explaining a third suppression method of the suppression device of the first embodiment. Fig. 6 is a schematic diagram showing a suppression device according to a second embodiment of the present invention. Fig. 7 is a diagram for explaining the suppression method of the suppression device according to the second embodiment. Fig. 8 is a schematic diagram showing a suppression device according to a third embodiment of the present invention. Fig. 9 is a schematic diagram showing a modified example of the suppression device of the third embodiment.

1: suppression device

10: 1st path

10A: end

11: 1st valve

12: Confluence Department

20: Bypass path

21: Bypass valve

30: Freezer

40: pump

50: 2nd path

51: 2nd valve

60: 3rd path

61: 3rd valve

70: Determination Department

T1: cargo tank

T2: storage tank

P1, P2, P3: parts

Claims (7)

A suppression device that suppresses BOG that occurs when cargo liquid is received from a cargo tank toward a storage tank, comprising: A refrigerating machine arranged on the path connecting the aforementioned liquid cargo tank and the aforementioned storage tank; and The pump is provided inside the storage tank, and can send the residual liquid in the storage tank toward the refrigerator. The suppressing device according to claim 1, further comprising: a bypass path provided to branch relative to the path connecting the liquid cargo tank and the storage tank. The suppressing device according to claim 1 or 2, further comprising: a measuring unit for measuring the temperature of a plurality of positions in the height direction in the storage tank. The suppression device according to any one of claims 1 to 3, wherein the path connecting the liquid cargo tank and the storage tank has: The upper path transports the liquefied gas cooled by the refrigerator to the upper side of the storage tank; and The lower path transports the liquefied gas cooled by the refrigerator to the lower side of the storage tank, Adjustment valves for adjusting the amount sent to the storage tank are provided on the upper path and the lower path. The suppression device according to any one of claims 1 to 4, wherein the aforementioned storage tanks are provided with a plurality of them, The aforementioned residual liquid in a storage tank is formed into a supercooled state by the aforementioned refrigerator, The excess liquid in the one storage tank that has been in a supercooled state is transferred to the other storage tanks by the pump. A suppressing method, suppressing BOG generated when cargo liquid is received from a cargo tank toward a storage tank by a suppressing device, the suppressing device having: a refrigerator arranged between a path connecting the liquid cargo tank and the storage tank; and a pump, which is installed inside the aforementioned storage tank, and can transport the residual liquid in the aforementioned storage tank toward the aforementioned refrigerator, and the aforementioned suppressing method has the following steps: When the aforementioned cargo liquid is received toward the aforementioned storage tank, the aforementioned cargo liquid is cooled to a supercooled state by the aforementioned refrigerator; and The cooled aforementioned cargo liquid is transported to the aforementioned storage tank. The suppressing method as claimed in item 6, which further has the following steps: The aforementioned residual liquid in the aforementioned storage tank is transported to the aforementioned refrigerator by the aforementioned pump, thereby cooling the aforementioned residual liquid originally located in the aforementioned storage tank to a supercooled state; mixing the aforesaid residual liquid in the aforesaid storage tank which has been cooled to a supercooled state with the aforesaid cargo liquid from the aforesaid cargo tank which has been cooled to a supercooled state; and The mixed aforementioned residual liquid and aforementioned cargo liquid are transported to the aforementioned storage tank.

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