LIQUEFIED GAS-BASED RAPID COOLING POSSIBILITY DETERMINATION DEVICE, LIQUEFIED GAS STORAGE TANK, LIQUEFIED GAS CARRYING VESSEL, AND LIQUEFIED GAS-BASED RAPID COOLING POSSIBILITY DETERMINATION METHOD

Abstract

The present invention provides a control device that includes a first temperature detection unit that detects a partition wall temperature of a tank main body in which liquefied gas is contained, and a second temperature detection unit that detects a temperature of a skirt that supports the tank main body. The control device further includes a temperature difference acquisition unit that acquires a temperature difference between the partition wall temperature detected by the first temperature detection unit and the temperature of the skirt which is detected by the second temperature detection unit, and a determination unit that determines whether or not a joint between the tank main body and the skirt is rapidly cooled by the liquefied gas on the basis of the partition wall temperature and the temperature difference.

Claims

1. A liquefied gas-based rapid cooling possibility determination device comprising: a first temperature detection unit configured to form a part of a partition wall of a tank in which liquefied gas is contained and to detect a temperature of a joining member to which the support member is joined; a second temperature detection unit configured to detect a temperature of a support member that supports the tank; a temperature difference acquisition unit configured to acquire a temperature difference between the temperature of the partition wall which is detected by the first temperature detection unit and the temperature of the support member which is detected by the second temperature detection unit; and a determination unit configured to determine whether or not a joint between the tank and the support member is rapidly cooled by the liquefied gas, on the basis of at least two of the temperature of the partition wall, the temperature of the support member, and the temperature difference.

2. (canceled)

3. The liquefied gas-based rapid cooling possibility determination device according to claim 1, wherein the second temperature detection unit detects a temperature of an upper part of the support member.

4. The liquefied gas-based rapid cooling possibility determination device according to claim 3, wherein the support member is configured such that an end thereof at a side joined to the partition wall has higher thermal conductivity than a portion thereof at a side separated from the partition wall.

5. The liquefied gas-based rapid cooling possibility determination device according to claim 1, wherein the determination unit determines whether or not the joint between the tank and the support member is rapidly cooled by the liquefied gas, on the basis of whether or not the temperature of the partition wall or the support member and the temperature difference are within a range within which stress generated at a joint between the partition wall and the support member when the tank is cooled by the liquefied gas is set to be lower than or equal to a predetermined reference value.

6. The liquefied gas-based rapid cooling possibility determination device according to claim 5, wherein the determination unit determines that rapid cooling of the tank caused by the liquefied gas into the tank is possible when the temperature of the partition wall is set to be lower than or equal to the predetermined reference value.

7. A liquefied gas storage tank comprising: a tank main body configured to store liquefied gas; a support member configured to support the tank main body; a precooling part configured to precool the tank main body; a gas feeder configured to feed the liquefied gas to the tank main body; and the liquefied gas-based rapid cooling possibility determination device defined by claim 1.

8. A liquefied gas carrying vessel comprising: the liquefied gas storage tank defined by claim 7; and a hull in which the liquefied gas storage tank is mounted.

9. A liquefied gas-based rapid cooling possibility determination method comprising: a process of forming a part of a partition wall of a tank in which liquefied gas is contained and detecting a temperature of a joining member to which the support member is joined; a process of detecting a temperature of a support member that supports the tank; a process of acquiring a temperature difference between the temperature of the partition wall and the temperature of the support member; and a process of determining whether or not a joint between the tank and the support member is rapidly cooled by the liquefied gas, on the basis of at least two of the temperature of the partition wall, the temperature of the support member, and the temperature difference.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0031] FIG. 1 is a sectional view of a tank provided in a carrying vessel in a first embodiment of the present invention.

[0032] FIG. 2 is an enlarged sectional view showing a constitution of a joint between a tank main body that constitutes the tank and a skirt that supports the tank main body in the first embodiment of the present invention.

[0033] FIG. 3 is a view showing a functional constitution of a control device in the first embodiment of the present invention.

[0034] FIG. 4 is a flow chart for control when the tank main body is precooled in the first embodiment of the present invention.

[0035] FIG. 5 is a view showing an example of a correlation map between a partition wall temperature and a temperature difference wherein the correlation map indicates a range in which stress generated at a joint between a partition wall and a support member when liquefied gas is loaded into the tank main body is lower than or equal to a predetermined reference value.

[0036] FIG. 6 is a flow chart for control when a tank main body is precooled in a second embodiment of the present invention.

[0037] FIG. 7 is a view showing an example of a correlation map corresponding to FIG. 5 in the second embodiment.

[0038] FIG. 8 is a flow chart of a method of setting a threshold line for determining whether or not it is possible to load the liquefied gas into the tank.

DESCRIPTION OF EMBODIMENTS

First Embodiment

[0039] Next, a carrying vessel according to a first embodiment of the present invention will be described with reference to the drawings.

[0040] FIG. 1 is a sectional view of a tank provided in a carrying vessel in a first embodiment of the present invention.

[0041] A carrying vessel (a liquefied gas carrying vessel) 10 of the present embodiment carries a liquefied gas such as liquefied natural gas (LNG).

[0042] As shown in FIG. 1, the carrying vessel 10 includes at least a hull 11 and a tank (a liquefied gas storage tank) 12.

[0043] The hull 11 includes a tank housing 14 that is formed of steel and forms a so-called hold space in which the tank 12 is housed. The tank housing 14 includes a housing recess 15 and a tank cover 13.

[0044] The housing recess 15 is recessed toward a lower bottom 11b with respect to the upper deck 11a, and opens upward. A plurality of tanks 12 are arranged in the housing recess 15 in parallel from the bow toward the stern of the hull 11.

[0045] The tank cover 13 mainly covers an upper part of the tank 12. The tank cover 13 is provided on the upper deck 11a of the hull 11. The tank cover 13 is formed in a shape that is curved upward.

[0046] Each tank 12 includes a tank main body 20 and a skirt (a support member) 22 that supports the tank main body 20.

[0047] The liquefied gas that is a carrying target is housed in the tank main body 20. The tank main body 20 is formed of a partition wall that partitions the inside and outside thereof.

[0048] The tank main body 20 is formed of, for example, an aluminum alloy, and has a spherical shape. The tank main body 20 is not limited to the spherical shape. The tank main body 20 may have, for example, a shape in which a vertical sectional shape is long in a vertical direction by forming a middle part thereof in a vertical direction in a tube or conical frustum shape having a constant diameter and forming upper and lower parts of the middle part in hemispherical shapes.

[0049] A pipe tower (a gas feeder) 21 that extends from a bottom 20b toward a top 20t of the tank main body 20 and has a hollow tube shape is provided in the tank main body 20. An upper part of the pipe tower 21 is provided with a spray nozzle (a precooling part) 21n that sprays the liquefied gas of the same type as the carrying target as a coolant into the tank main body 20 in order to precool the tank main body 20.

[0050] The liquefied gas of the carrying target is fed from the bottom 20b of the tank main body 20 through a gas feed pipe (not shown), and is thereby stored in the tank main body 20.

[0051] An outer surface of this tank main body 20 is covered with a heat insulator (not shown).

[0052] The skirt 22 is provided on a foundation deck 16 provided on the housing recess 15 in a cylindrical shape. The skirt 22 supports the tank main body 20 such that an upper part 20a of the tank main body 20 protrudes upward from the upper deck 11a of the hull 11.

[0053] FIG. 2 is an enlarged sectional view showing a constitution of joint between the tank main body and the skirt that supports the tank main body in the first embodiment of the present invention.

[0054] As shown in FIG. 2, the skirt 22 is joined to a joining member 23 provided on the tank main body 20. The joining member 23 is provided at a portion to which the skirt 22 is joined in the tank main body 20. The portion to which the skirt 22 is joined is, for example, a maximum diameter part (a so-called equatorial portion) in a vertical direction of the spherical tank main body 20 in the example of FIG. 2. The joining member 23 integrally includes a main body part 23a that forms a part of the partition wall of the tank main body 20, and a skirt joint 23b which branches off from the main body part 23a and extends downward and to which the skirt 22 is joined. The joining member 23 is formed of the same material as the tank main body 20.

[0055] The skirt 22 has an upper part 22a that is joined to the skirt joint 23b of the joining member 23 and is formed of an aluminum alloy. A lower part 22c of the skirt 22 joined to the foundation deck 16 is formed of steel that is the same material as the foundation deck 16 or the hull 11. In the skirt 22, a middle part 22b between the upper part 22a and the lower part 22c is formed of a material that has lower thermal conductivity than the upper part 22a, for example a stainless steel alloy.

[0056] FIG. 3 is a view showing a functional constitution of a control device in the first embodiment of the present invention.

[0057] Each tank 12 includes a control device (a liquefied gas-based rapid cooling possibility determination device) 30 (see FIG. 3) that controls loading of the liquefied gas to be carried into the tank main body 20.

[0058] As shown in FIG. 3, the control device 30 includes a first temperature detection unit 31, a second temperature detection unit 32, a temperature difference acquisition unit 33, a determination unit 34, a nozzle controller 35, and a pump controller 36.

[0059] The first temperature detection unit 31 detects a temperature of the partition wall of the tank main body 20. In the present embodiment, as shown in FIG. 2, the first temperature detection unit 31 is provided to detect, for example, a temperature of the main body part 23a of the joining member 23 as a partition wall temperature (a temperature of the partition wall) T1.

[0060] The second temperature detection unit 32 detects a temperature of the skirt 22. In the present embodiment, the second temperature detection unit 32 is formed of a material that has high thermal conductivity in the skirt 22, and is provided to detect a temperature of the upper part 22a adjacent to the skirt joint 23b as a skirt temperature T2.

[0061] As shown in FIG. 3, the temperature difference acquisition unit 33 calculates a temperature difference T (=T1T2) between the partition wall temperature T1 of the tank main body 20 which is detected by the first temperature detection unit 31 and the skirt temperature T2 of the skirt 22 which is detected by the second temperature detection unit 32.

[0062] The determination unit 34 determines whether or not it is possible to feed the liquefied gas acting as the carrying target into the tank main body 20.

[0063] The nozzle controller 35 controls ON/OFF of a spraying operation of a liquefied precooling gas (a coolant) from a spray nozzle 21n (see FIG. 1).

[0064] The pump controller 36 controls ON/OFF of a feeding operation of the liquefied gas into the tank main body 20 from a gas feed pipe (not shown).

[0065] FIG. 4 is a flow chart for control when the tank main body is precooled in the first embodiment of the present invention.

[0066] As shown in FIG. 4, before the liquefied gas is loaded into the tank main body 20, precooling of the tank 12 is started (step S101). Here, the liquefied gas of the same type as the liquefied gas to be carried is sprayed from the spray nozzle 21n in the tank main body 20 as the coolant by the nozzle controller 35 in the control device 30. Thereby, the tank main body 20 is cooled. Furthermore, the skirt 22 is cooled from the tank main body 20 via the joining member 23.

[0067] The control device 30 detects the partition wall temperature T1 of the tank main body 20 and the skirt temperature T2 of the skirt 22 at the first temperature detection unit 31 and the second temperature detection unit 32 at regular predetermined time intervals (step S102).

[0068] Next the control device 30 calculates (acquires) a temperature difference T (=T1T2) between the partition wall temperature T1 of the tank main body 20 which is detected by the first temperature detection unit 31 and the skirt temperature T2 of the skirt 22 which is detected by the second temperature detection unit 32 in the temperature difference acquisition unit 33 (step S103).

[0069] Subsequently, the determination unit 34 determines whether or not rapid cooling caused by the liquefied gas to be carried into the tank main body 20 is possible on the basis of the partition wall temperature T1 of the tank main body 20 which is detected in step S102 and the temperature difference T between the partition wall temperature T1 of the tank main body 20 and the skirt temperature T2 of the skirt 22 which is detected in step S103 (step S104).

[0070] Here, the determination unit 34 determines whether or not a predetermined precooling completion condition is satisfied on the basis of a correlation map between the partition wall temperature T1 and the temperature difference T.

[0071] FIG. 5 is a view showing an example of the correlation map between the partition wall temperature and the temperature difference wherein the correlation map indicates a range in which stress generated at the joint between the partition wall and the support member when the liquefied gas is loaded into the tank main body is lower than or equal to a predetermined reference value.

[0072] In FIG. 5, a threshold line L1 is expressed by, for example, Formula (1) below.

Y=aX+b (1)

[0073] Here, a and b are preset coefficients.

[0074] The threshold line L1 sets a boundary between a range A1 between the partition wall temperature T1 and the temperature difference T and a range other than the range A1, at which stress generated at a joint between the main body part 23a of the joining member 23 and the skirt 22 when the liquefied gas is loaded into the tank main body 20 is lower than or equal to a predetermined reference value.

[0075] In the correlation map shown in FIG. 5, if a point determined by the partition wall temperature T1 and the temperature difference T detected and acquired in steps S102 and S103 goes beyond the threshold line L1, and falls within the range A1 that satisfies the precooling completion condition, the determination unit 34 determines that a loading condition of the liquefied gas into the tank main body 20 is satisfied, and the loading is possible.

[0076] In this case, when the pump controller 36 receives an output signal from the determination unit 34, the pump controller 36 switches on a pump (not shown) that feeds the liquefied gas into the tank main body 20 from a gas feed pipe (not shown). Thereby, the loading of the liquefied gas into the tank main body 20 is started (step S105).

[0077] In this case, the nozzle controller 35 may be configured to stop the spraying operation of the precooling coolant from the spray nozzle 21n, and to stop precooling treatment of the tank main body 20.

[0078] In this case, since the temperature difference T between the tank main body 20 and the skirt 22 is suppressed when the loading of the liquefied gas is started, even if the tank main body 20 is subjected to shrinking deformation by the loading of the liquefied gas, a difference in amounts of deformation between the tank main body 20 and the skirt 22 is small. Therefore, the stress acting on the joint between the tank main body 20 and the skirt 22 can be suppressed.

[0079] In FIG. 5, a change curve P1 shows an example of a change between the partition wall temperature T1 and the temperature difference T when the precooling treatment of the tank main body 20 is performed. According to the change curve P1, when the precooling of the tank main body 20 is started, the tank main body 20 is reduced in temperature before the skirt 22, and thus the temperature difference T is increased. Afterward, the reduction in temperature of the tank main body 20 propagates to the skirt 22, and once a reduction in temperature of the skirt 22 starts, the temperature difference T becomes small. In an example of the change curve P1, when the temperature difference T becomes small (a point S1 in FIG. 5), the change curve P1 goes beyond the threshold line L1.

[0080] In contrast, in the case of a comparative example in which the possibility of the rapid cooling caused by the liquefied gas is determined only by the partition wall temperature T1, for example, when the partition wall temperature T1 is lower than or equal to a threshold temperature X in the change curve P1 (point S2 in FIG. 5), the loading of the liquefied gas is permitted.

[0081] In this way, the determination treatment based on the partition wall temperature T1 and the temperature difference T is performed, and thereby the loading of the liquefied gas can be started in an earlier stage.

[0082] Therefore, according to the aforementioned first embodiment, it can be determined, whether or not the joint between the tank main body 20 and the skirt 22 is rapidly cooled by the liquefied gas on the basis of the partition wall temperature T1 of the tank main body 20 and the temperature difference T between the partition wall temperature T1 and the skirt temperature T2 of the skirt 22. For his reason, it is determined in the determination unit 34 that, even in the state in which the partition wall temperature T1 does not go down to the threshold temperature X (for example 100 C.) used as, for example, a conventional precooling completion condition, if the temperature difference T between the partition wall temperature T1 and the skirt temperature T2 of the skirt 22 is small, the rapid cooling of the tank main body 20 caused by the liquefied gas is possible, and the loading of the liquefied gas is possible. In this way, a time required for the precooling performed during the loading of the liquefied gas can be shortened, and the loading of the liquefied gas to the tank main body 20 can be started in an early stage. As a result, the loading of the liquefied gas can be started at a proper timing.

[0083] The first temperature detection unit 31 forms a part of the main body part 23a of the joining member 23 of the tank main body 20, and can detect the temperature of the joining member 23 to which the skirt 22 is joined.

[0084] For this reason, the first temperature detection unit 31 can detect the partition wall temperature T1 at a position adjacent to the joint between the tank main body 20 and the skirt 22.

[0085] As a result, a change in the temperature of the tank main body 20 when the precooling of the tank main body 20 is performed can be detected with high sensitivity.

[0086] Furthermore, the second temperature detection unit 32 can detect the temperature of the upper part 22a at a side at which the skirt 22 is joined to the main body part 23a of the joining member 23. For this reason, a change in temperature caused by thermal propagation between the main body part 23a of the joining member 23 of the tank main body 20 and the skirt 22 during precooling can be detected at a position adjacent to the joint between the main body part 23a of the joining member 23 and the skirt 22 with high sensitivity.

[0087] Furthermore, the upper part 22a at the side at which the skirt 22 is joined to the main body part 23a of the joining member 23 is formed of a material having high thermal conductivity. For this reason, the temperature of the upper part 22a of the skirt 22 is detected by the second temperature detection unit 32. The change in temperature caused by thermal propagation between the main body part 23a of the joining member 23 of the tank main body 20 and the skirt 22 during precooling can be detected with higher sensitivity.

[0088] Furthermore, the determination unit 34 can determine whether or not the joint between the tank main body 20 and the skirt 22 is rapidly cooled by the liquefied gas on the basis of whether or not the partition wall temperature T1 and the temperature difference T are within a range within which the stress generated at the joint between the main body part 23a of the joining member 23 and the skirt 22 when the liquefied gas is loaded into the tank main body 20 is lower than or equal to a predetermined reference value. For this reason, the time required for the precooling performed during the loading of the liquefied gas can be shortened, and the loading of the liquefied gas can be started in an early stage.

Second Embodiment

[0089] Next, a second embodiment of the liquefied gas-based rapid cooling possibility determination device, the liquefied gas storage tank, the liquefied gas carrying vessel, or the liquefied gas-based rapid cooling possibility determination method according to the present invention will be described. In the second embodiment to be described below, since only the constitution of the map serving as the basis of determining whether or not the loading is started is different from that of the first embodiment, the same portions as in the first embodiment will be described with the same reference signs, and duplicate description will be omitted.

[0090] FIG. 6 is a flow chart for control when a tank main body is precooled in a second embodiment of the present invention.

[0091] As shown in FIG. 6, before a liquefied gas is loaded into a tank main body 20, precooling of a tank 12 is started (step S201). In this case, a control device 30 causes a liquefied gas of the same type as the liquefied gas to be carried to be sprayed as a coolant from a spray nozzle 21n in the tank main body 20 by a nozzle controller 35. Thereby, the tank main body 20 is cooled. Furthermore, a skirt 22 is cooled via a joining member 23.

[0092] The control device 30 detects a partition wall temperature T1 of the tank main body 20 and a skirt temperature T2 of the skirt 22 at a first temperature detection unit 31 and a second temperature detection unit 32 at regular predetermined time intervals (step S202).

[0093] Next, the control device 30 calculates (acquires) a temperature difference T (=T1T2) between the partition wall temperature T1 of the tank main body 20 which is detected by the first temperature detection unit 31 and the skirt temperature T2 of the skirt 22 which is detected by the second temperature detection unit 32 in a temperature difference acquisition unit 33 (step S203).

[0094] Subsequently, a determination unit 34 determines whether or not the tank main body 20 is rapidly cooled by the liquefied gas on the basis of the partition wall temperature T1 of the tank main body 20 which is detected in step S202 and the temperature difference T between the partition wall temperature T1 of the tank main body 20 and the skirt temperature T2 of the skirt 22 which is detected in step S203, and whether or not the loading of the liquefied gas into the tank main body 20 is possible.

[0095] Here, it is first determined whether or not the partition wall temperature T1 of the tank main body 20 which is detected in step S202 is lower than or equal to a predetermined threshold Z, for example 100 C. (step S204).

[0096] If the result of the determination indicates that the partition wall temperature T1 is lower than or equal to the threshold Z (T1Z), the determination unit 34 determines that the rapid cooling of the tank main body 20 caused by the liquefied gas is possible, and the loading of the liquefied gas into the tank main body 20 is possible.

[0097] Meanwhile, in the case where the partition wall temperature T1 is not the threshold or less, it is subsequently determined whether or not a predetermined precooling completion condition is satisfied, for example, according to a correlation map between the partition wall temperature T1 and the temperature difference T as shown in FIG. 7 (step S205). In FIG. 7, a threshold line L2 is expressed by, for example, Formula (2) below.

Y=aX+b, and X<Z (2)

[0098] Here, a and b are preset coefficients.

[0099] In the correlation map shown in FIG. 7, if a point determined by the partition wall temperature T1 and the temperature difference T detected and acquired in steps S202 and S203 beyond the threshold line L2, and falls within a range A2 that satisfies the precooling completion condition, the determination unit 34 determines that the rapid cooling of the tank main body 20 caused by the liquefied gas is possible, and the loading of the liquefied gas into the tank main body 20 is possible.

[0100] In step S204 or S205, in the case where it is determined in the determination unit 34 that the rapid cooling of the tank main body 20 caused by the liquefied gas is possible, and the loading of the liquefied gas is possible, the pump controller 36 switches on a pump (not shown) that feeds the liquefied gas into the tank main body 20 from a gas feed pipe (not shown). Thereby, the loading of the liquefied gas into the tank main body 20 is started (step S206).

[0101] In this case, the nozzle controller 35 may be configured to stop a spraying operation of the precooling coolant from the spray nozzle 21n, and to stop precooling treatment of the tank main body 20.

[0102] Therefore, according to the aforementioned second embodiment, like the first embodiment, it is determined whether or not the joint between the tank main body 20 and the skirt 22 is rapidly cooled by the liquefied gas on the basis of the partition wall temperature T1 of the tank main body 20 and the temperature difference T between the partition wall temperature T1 and the skirt temperature T2 of the skirt 22. Thereby, a time required for the precooling performed during the loading of the liquefied gas can be shortened, and the loading of the liquefied gas can be started in an early stage. Therefore, the loading of the liquefied gas into the tank main body 20 can be started at a proper timing.

[0103] The determination unit 34 determines that the loading of the liquefied gas into the tank main body 20 is possible when the partition wall temperature T1 is lower than or equal to a predetermined reference value. For this reason, even in the state in which the temperature difference T between the partition wall temperature T1 of the tank main body 20 and the skirt temperature T2 of the skirt 22 is large, the loading of the liquefied gas into the tank main body 20 can be started in an early stage if the partition wall temperature T1 is lower than or equal to the predetermined reference value.

[0104] Next, a method of obtaining Formulae (1) and (2) for setting the threshold lines L1 and L2 exemplified in the aforementioned first and second embodiments will be described.

[0105] FIG. 8 is a flow chart of a method of setting a threshold line for determining whether or not it is possible to load the liquefied gas into the tank.

[0106] As shown in FIG. 8, first, temperature distribution of the tank main body 20, the joining member 23, and the skirt 22 in the state in which the precooling is performed on the tank 12 or in the state in which the carrying vessel 10 is under sail is simulated by, for example, a finite element method (FEM) analysis (step S301).

[0107] Next, the temperature distribution obtained in step S301 is set as an initial condition, and temperature distribution of the case where the joining member 23 is rapidly cooled by the liquefied gas when the liquefied gas is loaded into the tank main body 20 or when the liquefied gas is fluctuated in the tank main body 20 under sail is simulated by an FEM analysis (step S302).

[0108] Next, stress, which is generated at the boundary portion between the main body part 23a of the joining member 23 and the skirt joint 23b when the temperature distribution obtained during rapid cooling in step S302 is given to the joining member 23 as a thermal load, is obtained (step S303).

[0109] Subsequently, it is checked that the stress obtained in step S303 falls within a predetermined reference value (step S304).

[0110] The temperature distribution in which the rapid cooling is permitted is specified in the joining member 23 according to a series of processes of steps S301 to S304, and Formulae (1) and (2) for setting the threshold lines L1 and L2 are obtained (step S305).

Other Modifications

[0111] The present invention is not limited to the aforementioned embodiments, and includes modifying the aforementioned embodiments in various ways without departing from the spirit and scope of the present invention. That is, the specific shape and constitution represented in the embodiments are merely examples, and can be appropriately modified.

[0112] For example, in FIGS. 5 and 7, the threshold lines L1 and L2 are given as an example. However, threshold lines other than those given as an example may be used as long as it is determined whether or not the liquefied gas is loaded on the basis of the partition temperature T1 and the temperature difference T.

[0113] Furthermore, the temperature of the joining member 23 is configured to be detected as the partition wall temperature T1. However, a temperature of another part may be configured to be detected as long as the temperature of the partition wall of the tank main body 20 can be detected.

[0114] Furthermore, the skirt temperature T2 may also be configured to be detected at a part other than the upper part 22a of the skirt 22.

[0115] In each of the above embodiments, it is determined whether or not the joint between the tank main body 20 and the skirt 22 is rapidly cooled by the liquefied gas on the basis of the partition wall temperature T1 and the temperature difference T between and the partition wall temperature T1 and the skirt temperature T2, but the present invention is not limited thereto. To determine whether or not the joint between the tank main body 20 and the skirt 22 is rapidly cooled by the liquefied gas need only be performed on the basis of at least two of the partition wall temperature the skirt temperature T2, and the temperature difference T. For example, it is determined whether or not the joint between the tank main body 20 and the skirt 22 may be rapidly cooled by the liquefied gas on the basis of the skirt temperature T2 and the temperature difference T. It is determined whether or not the joint between the tank main body 20 and the skirt 22 may be rapidly cooled by the liquefied gas on the basis of the partition wall temperature T1 and the skirt temperature T2 of the skirt 22.

[0116] In each of the above embodiments, it is determined whether or not the tank is rapidly cooled by the liquefied gas, and thereby it is determined whether or not the liquefied gas is loaded. However, an application of the result of determining whether or not the rapid cooling is possible is not limited thereto.

INDUSTRIAL APPLICABILITY

[0117] According to the liquefied gas-based rapid cooling possibility determination device, the liquefied gas storage tank, the liquefied gas carrying vessel and the liquefied gas-based rapid cooling possibility determination method, it can be properly determined whether or not the joint between the tank and the support member is rapidly cooled by the liquefied gas.

REFERENCE SIGNS LIST

[0118] 10 Carrying vessel (liquefied gas carrying vessel)

[0119] 11 Hull

[0120] 11a Upper deck

[0121] 11b Bottom

[0122] 11c Bow

[0123] 11d Stern

[0124] 12 Tank (liquefied gas storage tank)

[0125] 13 Tank cover

[0126] 14 Tank housing

[0127] 15 Housing recess

[0128] 16 Foundation deck

[0129] 20 Tank main body

[0130] 20a Upper part

[0131] 20b Bottom

[0132] 20t Top

[0133] 21 Pipe tower

[0134] 21n Spray nozzle (precooling part)

[0135] 22 Skirt (support member)

[0136] 22a Upper part

[0137] 22b Middle part

[0138] 22c Lower part

[0139] 23 Joining member

[0140] 23a Main body part

[0141] 23b Skirt joint

[0142] 30 Control device (liquefied gas-based rapid cooling possibility determination device)

[0143] 31 First temperature detection unit

[0144] 32 Second temperature detection unit

[0145] 33 Temperature difference acquisition unit

[0146] 34 Determination unit

[0147] 35 Nozzle controller

[0148] 36 Pump controller

[0149] A1 Range

[0150] A2 Range

[0151] L1, L2 Threshold line

[0152] P1 Change curve

[0153] T1 Partition wall temperature (temperature of partition wall)

[0154] T2 Skirt temperature (temperature of support member)

[0155] Z Threshold

[0156] T Temperature difference