阅读说明：本技术 液化氢运输船和船体保护方法 (Liquefied hydrogen carrier and hull protection method ) 是由 后神一藤 大桥徹也 铃木智实 于 2019-02-28 设计创作，主要内容包括：液化氢运输船具有：船体；罐,其搭载于船体,并且包含贮存液化氢的罐主体和覆盖罐主体的隔热层；罐罩,其与船体一起形成收纳罐的保持空间；氮气提供装置,其向保持空间内提供氮气；海水提供装置,其向保持空间内提供海水；温度计,其测量隔热层的表面的温度或隔热层的内部的温度；以及控制装置,其在由温度计测量的温度低于设定值时,对海水提供装置进行控制,使得在保持空间的底部形成海水层。(The liquefied hydrogen carrier has: a hull; a tank mounted on a ship body, the tank including a tank main body for storing liquefied hydrogen and a heat insulating layer for covering the tank main body; a tank cover that forms a holding space for accommodating the tank together with the hull; a nitrogen gas supply device which supplies nitrogen gas into the holding space; a seawater supply device for supplying seawater into the holding space; a thermometer that measures a temperature of a surface of the heat insulating layer or a temperature of an inside of the heat insulating layer; and a control device which controls the seawater supply device so that a seawater layer is formed at the bottom of the holding space when the temperature measured by the thermometer is lower than a set value.)

1. A liquefied hydrogen carrier having:

a hull;

a tank mounted on the hull, the tank including a tank main body that stores liquefied hydrogen and a heat insulating layer that covers the tank main body;

a tank cover that forms a holding space for accommodating the tank together with the hull;

a nitrogen gas supply device that supplies nitrogen gas into the holding space;

a seawater supply device that supplies seawater into the holding space;

a thermometer that measures a temperature of a surface of the thermal insulation layer or a temperature of an interior of the thermal insulation layer; and

a control device which controls the seawater supply device so that a seawater layer is formed at the bottom of the holding space when the temperature measured by the thermometer is lower than a set value.

2. A liquefied hydrogen carrier having:

a hull;

a tank mounted on the hull, the tank including a tank main body that stores liquefied hydrogen and a heat insulating layer that covers the tank main body;

a tank cover that forms a holding space for accommodating the tank together with the hull;

a nitrogen gas supply device that supplies nitrogen gas into the holding space;

a seawater supply device that supplies seawater into the holding space;

a thermometer that measures a temperature of a portion of the hull located below the tank; and

a control device which controls the seawater supply device so that a seawater layer is formed at the bottom of the holding space when the temperature measured by the thermometer is lower than a set value.

3. The liquefied hydrogen carrier according to claim 1 or 2,

the thermal insulation layer comprises:

an outer tub separated from and surrounding the tank body; and

a vacuum space between the outer tank and the canister body.

4. The liquefied hydrogen carrier according to any one of claims 1 to 3,

the seawater supply device comprises:

a fire-fighting pipe disposed on a deck of the hull; and

and a branch pipe branching from the fire-fighting piping.

5. A method for protecting a ship hull equipped with a tank including a tank main body for storing liquefied hydrogen and a heat insulating layer for covering the tank main body, wherein a holding space for storing the tank and filled with nitrogen gas is formed between the ship hull and a tank cover,

when the temperature of the surface of the thermal insulation layer of the tank, the temperature of the interior of the thermal insulation layer, or the temperature of the portion of the hull located below the tank is lower than a set value, seawater is supplied into the holding space to form a seawater layer at the bottom of the holding space.

Technical Field

The invention relates to a liquefied hydrogen carrier and a hull protection method.

Background

In recent years, liquefied hydrogen carriers for transporting liquefied hydrogen have been developed. For example, patent document 1 discloses a liquefied hydrogen carrier that can also transport liquefied hydrogen.

In the liquefied gas carrier disclosed in patent document 1, a tank cover is disposed above a tank mounted on a hull. The tank cover forms a holding space for accommodating the tank together with the hull. An inert gas such as nitrogen is supplied into the holding space.

The tank includes a tank main body storing liquefied gas and an insulating layer covering the tank main body. In the liquefied gas carrier disclosed in patent document 1, the heat insulating layer includes an outer tank that is separate from the tank main body and surrounds the tank main body, and a vacuum space between the outer tank and the tank main body.

Disclosure of Invention

Problems to be solved by the invention

In the liquefied gas carrier disclosed in patent document 1, when the liquefied gas stored in the tank is liquefied hydrogen and the inert gas supplied into the holding space of the storage tank is nitrogen gas, liquefied nitrogen (about-196 ℃) may be generated on the surface of the heat insulating layer of the tank when the performance of the heat insulating layer of the tank deteriorates.

Since the hull is usually made of a steel material that is not used for low-temperature use, there is a possibility that a problem may occur in the hull when liquefied nitrogen generated on the surface of the heat insulating layer of the tank falls down to a portion of the hull located below the tank.

Accordingly, an object of the present invention is to provide a liquefied hydrogen carrier and a hull protecting method capable of preventing a problem from occurring in a hull due to liquefied nitrogen.

Means for solving the problems

In order to solve the above problem, a liquefied hydrogen carrier according to an aspect of the present invention includes: a hull; a tank mounted on the hull, the tank including a tank main body that stores liquefied hydrogen and a heat insulating layer that covers the tank main body; a tank cover that forms a holding space for accommodating the tank together with the hull; a nitrogen gas supply device that supplies nitrogen gas into the holding space; a seawater supply device that supplies seawater into the holding space; a thermometer that measures a temperature of a surface of the thermal insulation layer or a temperature of an interior of the thermal insulation layer; and a control device which controls the seawater supply device so that a seawater layer is formed at the bottom of the holding space when the temperature measured by the thermometer is lower than a set value.

According to the above configuration, if the set value is set in advance to a temperature at which the performance of the heat insulating layer is expected to deteriorate, the seawater layer is already formed at the bottom of the holding space when the performance of the heat insulating layer of the tank deteriorates and liquefied nitrogen is generated on the surface of the heat insulating layer. Therefore, even if the liquefied nitrogen falls, it does not come into direct contact with the hull. That is, the falling liquefied nitrogen is heated by contact with the seawater layer. Therefore, the occurrence of defects in the hull due to the liquefied nitrogen can be prevented.

In addition, a liquefied hydrogen carrier according to another aspect of the present invention includes: a hull; a tank mounted on the hull, the tank including a tank main body that stores liquefied hydrogen and a heat insulating layer that covers the tank main body; a tank cover that forms a holding space for accommodating the tank together with the hull; a nitrogen gas supply device that supplies nitrogen gas into the holding space; a seawater supply device that supplies seawater into the holding space; a thermometer that measures a temperature of a portion of the hull located below the tank; and a control device which controls the seawater supply device so that a seawater layer is formed at the bottom of the holding space when the temperature measured by the thermometer is lower than a set value.

According to the above configuration, if the set value is set in advance to the temperature at which the liquefied nitrogen is supposed to fall, a sea water layer is formed at the bottom of the holding space immediately after the liquefied nitrogen starts to fall. Therefore, the liquefied nitrogen that falls thereafter does not come into direct contact with the hull. Therefore, the occurrence of defects in the hull due to the liquefied nitrogen can be prevented.

For example, the thermal insulation layer may include: an outer tub separated from and surrounding the tank body; and a vacuum space between the outer tank and the can body.

The seawater supply apparatus may also include: a fire-fighting pipe disposed on a deck of the hull; and a branch pipe branching from the fire-fighting pipe. With this configuration, the seawater supply device for supplying seawater into the holding space can be configured by the fire fighting equipment necessary for the ship.

A method for protecting a ship hull according to the present invention is a method for protecting a ship hull equipped with a tank including a tank main body for storing liquefied hydrogen and a heat insulating layer for covering the tank main body, and a holding space for storing the tank and filled with nitrogen gas is formed between the ship hull and a tank cover, wherein when a temperature of a surface of the heat insulating layer of the tank, a temperature of an inside of the heat insulating layer, or a temperature of a portion of the ship hull located below the tank is lower than a set value, seawater is supplied into the holding space, and a seawater layer is formed at a bottom of the holding space.

According to the above configuration, the same effects as those of the liquefied hydrogen carrier of the present invention can be obtained.

Effects of the invention

According to the present invention, it is possible to prevent the occurrence of defects in the hull due to the liquefied nitrogen.

Drawings

Fig. 1 is a side view of a liquefied hydrogen carrier according to embodiment 1 of the present invention.

Fig. 2 is a cross-sectional view taken along line II-II of fig. 1.

Fig. 3 is a longitudinal sectional view taken along the line III-III of fig. 2.

Fig. 4 is a cross-sectional view of a liquefied hydrogen carrier according to embodiment 2 of the present invention.

Fig. 5 is a longitudinal sectional view taken along line V-V of fig. 4.

Detailed Description

Fig. 1 shows a liquefied hydrogen carrier 1A according to embodiment 1 of the present invention. The liquefied hydrogen carrier 1A includes a hull 2 and two tanks 3 mounted on the hull 2. The tanks 3 are arranged in the ship length direction. However, the number of tanks 3 mounted on the hull 2 may be one, or may be three or more.

In the present embodiment, the tank 3 is a cylindrical shape that is long in the horizontal direction (the ship length direction). However, the shape of the tank 3 may be spherical, cubic or rectangular.

As shown in fig. 2 and 3, each tank 3 includes a tank body 31 that stores liquefied hydrogen, and a heat insulating layer 32 that covers the tank body 31. In the present embodiment, the heat insulating layer 32 includes an outer tank 33 that is separate from the tank main body 31 and surrounds the tank main body 31, and a vacuum space 34 between the outer tank 33 and the tank main body 31. However, the heat insulating layer 32 may be formed of a plurality of heat insulating materials (for example, vacuum insulation panels) arranged on the surface of the tank main body 31. Although not shown, a vacuum heat insulating material is disposed in the vacuum space 34 so as to be separated from the inner surface of the outer tank 33 and to be wrapped around the tank main body 31.

More specifically, the tank body 31 includes a body portion extending in the ship-length direction with a constant cross-sectional shape, and a hemispherical closing portion closing openings on both sides of the body portion. However, the closing portion may be a plane perpendicular to the main body portion, or may be a disk-like shape. The outer tank 33 has a shape obtained by expanding the tank main body 31.

Two cargo tanks 21 opened upward are formed in the hull 2. The cargo holds 21 are arranged in the longitudinal direction of the ship, and the cargo holds 21 are separated from each other by bulkheads 22. The lower part of the tank 3 is inserted into each cargo tank 21. That is, the bottom surface 21a of the cargo tank 21 is a portion of the hull 2 located below the tank 3.

A pair of saddles 25 are provided inside each cargo tank 21 so as to be separated from each other in the axial direction of the tank 3. The saddle 25 supports the outer groove 33 of the tank 3. Further, a pair of support members 35 that support the tank main body 31 at the same positions as the saddles 25 are provided between the tank main body 31 and the outer tank 33 of the tank 3.

The hull 2 comprises: a bow deck 2a located forward of the cargo hold 21; side decks 2b, 2c, which are located on both sides of the cargo hold 21; and a stern deck 2d located rearward of the cargo hold 21. Further, an engine room 23 is formed in the hull 2 behind the cargo tank 21.

A tank cover 4 is disposed above each tank 3. Each tank cover 4 forms a holding space 5 for accommodating the tank 3 together with the cargo hold 21 of the hull 2.

Further, a nitrogen gas supply device 6 and a seawater supply device 7 are mounted on the hull 2, the nitrogen gas supply device 6 supplying nitrogen gas into each holding space 5, and the seawater supply device 7 supplying seawater into each holding space 5.

The nitrogen gas supply device 6 includes: a nitrogen gas generator 61; a header 62 extending from the nitrogen generator 61; and two branch pipes 63 which branch from the parent pipe 62 and extend into the two holding spaces 5. The nitrogen gas generator 61 is disposed in the engine compartment 23, for example, and includes a separation membrane that selectively transmits nitrogen gas in the air. The nitrogen gas supply device 6 continues to supply nitrogen gas into the holding space 5 except for a special case where the occupant gets into the holding space 5. Thereby, the holding space 5 is filled with nitrogen gas.

The seawater supply device 7 also serves as a fire fighting device in this embodiment. Specifically, the seawater supply device 7 includes a seawater pump 71, a fire-fighting pipe 72, and two branch pipes 73. The sea water pump 71 is disposed in the engine room 23 and draws sea water from the outside of the hull 2. The fire-fighting piping 72 extends from the seawater pump 71 to the side deck 2b, and is disposed on the side deck 2 b. The two branch pipes 73 branch from the fire-fighting pipe 72 and extend into the two holding spaces 5. In the present embodiment, each branch pipe 73 extends to the vicinity of the bottom 21a of the cargo compartment 21. Each branch pipe 73 is provided with an opening/closing valve 74.

The seawater supply device 7 is controlled by a control device 8 (see fig. 2). The control device 8 may be disposed in the bridge portion 20 of the hull 2 or may be disposed in the engine room 23. The control device 8 may be a single device or may be divided into a plurality of devices. The control device 8 is a computer having a memory such as a ROM or a RAM and a CPU, and executes a program stored in the ROM by the CPU.

The control device 8 is electrically connected to thermometers 9 provided for the respective tanks 3. However, in order to simplify the drawing, the connecting lines are not shown. In the present embodiment, each thermometer 9 measures the temperature of the surface of the heat insulating layer 32 (more precisely, the outer surface of the outer tank 33) of the corresponding tank 3. However, each thermometer 9 may measure the temperature of the inside of the heat insulating layer 32 of the corresponding tank 3 (for example, the inner surface of the outer tank 33 or a vacuum heat insulating material (not shown)).

The thermometer 9 is preferably disposed at the lowermost point of the outer tank 33, i.e., on a straight line in the axial direction of the tank 3. In the present embodiment, the thermometer 9 is located at the lowest point of the outer tank 33 and at the center in the axial direction of the tank 3.

Further, when the temperature measured by any of the thermometers 9 is lower than the set value Ts1, the control device 8 controls the seawater supply device 7 so that a seawater layer is formed at the bottom of the corresponding holding space 5.

The set value Ts1 is a temperature at which the performance of the thermal insulation layer 32 is assumed to be deteriorated. For example, the set value Ts1 is set within the range of-70 ℃ to-50 ℃. Alternatively, the set value Ts1 may be set to-10 ℃ or lower because the strength of the material constituting the hull 2 decreases at-10 ℃ or lower.

When the surface temperature of the heat insulating layer 32 of the tank 3 measured by the thermometer 9 is lower than the set value Ts1, the controller 8 opens the opening/closing valve 74 to form a sea water layer on the bottom surface 21a of the cargo hold 21. In addition, the depth of the sea water layer is about several tens millimeters to several hundreds millimeters.

In the illustrated example, each branch pipe 73 is located forward of the saddle 25 in front in the ship length direction, but the position of the branch pipe 73 is not particularly limited. Although not shown, the saddle 25 is provided with a plurality of openings for passing seawater in the ship length direction.

As described above, in the liquefied hydrogen carrier 1A of the present embodiment, when the performance of the heat insulating layer 32 of the tank 3 deteriorates and liquefied nitrogen is generated on the surface of the heat insulating layer 32, a sea water layer is already formed at the bottom of the holding space 5. Therefore, even if the liquefied nitrogen falls, it does not directly contact the hull 2 (the bottom surface 21a of the cargo tank 21). That is, the falling liquefied nitrogen is heated by contact with the seawater layer. Therefore, the occurrence of defects in the hull 2 due to the liquefied nitrogen can be prevented.

(embodiment 2)

Fig. 4 and 5 show a liquefied hydrogen carrier 1B according to embodiment 2 of the present invention. In the present embodiment, the same components as those in embodiment 1 are denoted by the same reference numerals, and redundant description thereof is omitted.

In the present embodiment, the thermometer 9 provided for each tank 3 is provided on the bottom surface 21a of the cargo hold 21 (the portion of the hull 2 located below the tank 3), and the temperature of the bottom surface 21a is measured. Further, as in embodiment 1, when the temperature measured by any of the thermometers 9 is lower than the set value Ts2, the controller 8 controls the seawater supplier 7 so that a seawater layer is formed at the bottom of the corresponding holding space 5.

The set point Ts2 is the temperature at which the liquefied nitrogen is supposed to fall. For example, the set value Ts2 is set in the range of-10 ℃ to 0 ℃. Alternatively, the set value Ts2 may be set to-10 ℃ or lower because the strength of the material constituting the hull 2 decreases at-10 ℃ or lower.

In the liquefied hydrogen carrier 1B of such a structure, a sea water layer is formed at the bottom of the holding space 5 immediately after the liquefied nitrogen starts to fall. Therefore, the liquefied nitrogen that falls thereafter does not come into direct contact with the hull 2 (the bottom surface 21a of the cargo tank 21). Therefore, the occurrence of defects in the hull 2 due to the liquefied nitrogen can be prevented.

(other embodiments)

The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present invention.

For example, the on-off valve 74 does not necessarily have to be controlled by the control device 8, and may be manually operated. For example, it may be notified to the occupant by an alarm or the like that the temperature measured by the thermometer 9 is lower than the set value Ts, and the occupant opens the on-off valve 74 at that time.

The seawater supply device 7 does not necessarily need to be used as a fire fighting device, and may be provided separately from the fire fighting device. However, if the structure as in the above embodiment is adopted, the seawater supply device 7 for supplying seawater into the holding space 5 can be configured by a fire fighting equipment necessary for the ship.

Description of the reference symbols

1A, 1B: a liquefied hydrogen carrier; 2: a hull; 2a to 2 d: a deck; 3: a tank; 31: a canister body; 32: a thermal insulation layer; 33: an outer tank; 34: a vacuum space; 4: a tank cover; 5: a holding space; 6: a nitrogen gas supply device; 7: a seawater supply device; 72: a fire-fighting piping; 73: a branch pipe; 8: a control device; 9: a thermometer.