PH12015000369B1 - Liquefied gas storage tank and vessel - Google Patents
Liquefied gas storage tank and vessel Download PDFInfo
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- PH12015000369B1 PH12015000369B1 PH12015000369A PH12015000369A PH12015000369B1 PH 12015000369 B1 PH12015000369 B1 PH 12015000369B1 PH 12015000369 A PH12015000369 A PH 12015000369A PH 12015000369 A PH12015000369 A PH 12015000369A PH 12015000369 B1 PH12015000369 B1 PH 12015000369B1
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- gaseous
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- liquefied gas
- tank body
- independent
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- 239000007792 gaseous phase Substances 0.000 claims abstract description 104
- 239000007789 gas Substances 0.000 claims abstract description 85
- 238000004891 communication Methods 0.000 claims abstract description 57
- 238000006073 displacement reaction Methods 0.000 claims description 15
- 238000007599 discharging Methods 0.000 claims description 3
- 239000012071 phase Substances 0.000 claims description 2
- 239000003915 liquefied petroleum gas Substances 0.000 description 8
- 239000007791 liquid phase Substances 0.000 description 7
- 230000007423 decrease Effects 0.000 description 6
- 238000009434 installation Methods 0.000 description 6
- 239000007788 liquid Substances 0.000 description 4
- 238000010276 construction Methods 0.000 description 2
- 239000003949 liquefied natural gas Substances 0.000 description 2
- 238000005192 partition Methods 0.000 description 2
- 238000011084 recovery Methods 0.000 description 2
- 238000004088 simulation Methods 0.000 description 2
- 239000004215 Carbon black (E152) Substances 0.000 description 1
- 238000007792 addition Methods 0.000 description 1
- 238000005452 bending Methods 0.000 description 1
- 230000033228 biological regulation Effects 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
- 150000002430 hydrocarbons Chemical class 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 239000011810 insulating material Substances 0.000 description 1
- 238000003754 machining Methods 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Filling Or Discharging Of Gas Storage Vessels (AREA)
- General Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Ocean & Marine Engineering (AREA)
Abstract
A liquefied gas storage tank includes a tank body 7 having therein a storage space 10 that stores liquefied gas; a trunk top 8 that protrudes upward from the tank body 7 and has therein a convex space 21 that communicates with the storage space 10; and a communication part 9 that allows an upper gaseous-phase region of the convex space 21 where a gaseous phase of the liquefied gas is present to communicate with an independent gaseous-phase generation region of the storage space 10 where a gaseous phase, which is independent from the gaseous phase of the convex space 21, capable of being generated.
Description
;
LIQUEFIED GAS STORAGE TANK AND VESSEL
The present invention relates to a liquefied gas storage tank and a vessel.
In order to carry cryogenic liquids or the like, there are known vessels in which storage tanks, such as box-shaped cargo tanks of which a longitudinal section in a vessel width direction forms a polygonal shape, or spherical tanks, are installed in a hull. Each of such storage tanks often has a structure referred to as a trunk top for performing loading and unloading in an upper part thereof. Various pipes and devices, such as pressure-relief valves, which relieve pressure for the protection of the tank, when the pressure within the storage tank has risen higher than a predetermined pressure, are installed in this trunk top.
In the above-described storage tank, it is desired that the stowage rate of liquefied gas that is a cargo is as high as possible in order to raise transport efficiency.
For example, when navigation for one month is performed at a stowage rate of about 98%, the cargo may expand due to a temperature rise or the like, and the stowage rate may become about 99.5% during unloading. In this case, a slight gaseous phase is secured inside the above-described trunk top, and an end of a pressure-relief valve is not soaked in a liquid phase.
As a technique of discharging the gas within the storage tank to the outside, a recovery device that traps the gas within the tank after the cargo that generates volatile ) gas is unloaded, thereby recovering hydrocarbon gas, is described in Japanese
Unexamined Patent Application, First Publication No. S59-164286. The recovery device of this Japanese Unexamined Patent Application, First Publication No.
S59-164286 has a conduit that returns unrecovered inert gas into the tank.
In the above-described storage tank that carries liquefied gas, limitations are given to the structure of the cargo tank according to International Code For The )
Construction And Equipment Of Ships Carrying Liquefied Gases In Bulk (hereinafter referred to as "IGC Code"). That is, the above-described storage tank is designed such that the total volume thereof is made as large as possible within a range of the structure specified in the "IGC Code". Keeping the above-described pressure-relief valve from being soaked in the liquid phase is also specified in this "IGC Code".
In the above-described "IGC Code", the following rule is applied to new ships that constructed after July 1, 2016. This rule says that "in a liquefied gas carrier that operates at a cargo stowage rate exceeding 98%, an independent gas pocket should not be present within a cargo tank in a state (a)". The state (a) is as follows. 1.5% Lpp trim (bow and stern) and 15 degree list (a)
The "Lpp" is the length between bow-stern perpendicular lines of a vessel on which the cargo tank is mounted.
In the above-described storage tank, when the cargo stowage rate exceeds 98%
and the liquefied gas carrier inclines on the condition (a), a gas pocket may be independently formed in a shoulder of a storage tank body. Therefore, if an attempt to reliably satisfy the regulations of the "IGC Code" is made, it is necessary to suppress the ’ stowage rate of the liquefied gas to 98% or less. If the stowage rate of the liquefied gas is suppressed to be low in this way, the amount of the liquefied gas that can be carried during one navigation may decrease, and the transport efficiency may deteriorate.
An object of the invention is to provide a liquefied gas storage tank and a vessel that can satisfy requirements specified in the "IGC Code" without lowering the stowage rate of liquefied gas, and can suppress a decline in transport efficiency.
According to a first aspect of the invention, the liquefied gas storage tank includes a tank body having therein a storage space that stores liquefied gas. The - liquefied gas storage tank further includes a trunk top that protrudes upward from the tank body and has therein a convex space that communicates with the storage space.
The liquefied gas storage tank further includes a communication part that allows an upper gaseous-phase region of the convex space where a gaseous phase of the liquefied gas is present to communicate with an independent gaseous-phase generation region of the storage space where a gaseous phase, which is independent from the gaseous phase of the convex space, capable of being generated.
By adopting such a configuration, the communication part enables the upper . gaseous-phase region present in the convex space of the trunk top and the independent gaseous-phase generation region of the storage space of the tank body to communicate with each other. Therefore, a situation in which the gascous phase that can be generated in the storage space of the tank body becomes independent can be suppressed. As a result, the requirements specified in the "IGC Code" can be satisfied without lowering the stowage rate of the liquefied gas. Accordingly, a decline in transport efficiency can be suppressed. .
According to a second aspect of the invention, the liquefied gas storage tank further includes a relief valve capable of discharging the gaseous phase of the convex space to the outside of the tank body when the inside of the tank body exceeds a predetermined pressure.
By adopting such a configuration, the gaseous phase is secured in the convex space such that the relief valve is not soaked in the liquid phase in the convex space of the trunk top. Therefore, even if the gaseous phase is generated in the storage space of } the tank body, the gaseous phase in the storage space can be relieved to the outside of the tank body if the communication part allows the gaseous phase in the convex space and the gaseous phase in the storage space to communicate with each other and the relief valve is operated.
According to a third aspect of the invention, in the liquefied gas storage tank, the communication part in the first or second aspect may allow the upper gaseous-phase region and the independent gaseous-phase generation region to communicate with each other outside the tank body.
By adopting such a configuration, the communication part can be easily added to a tank having the same shape as an existing tank. Therefore, design can be kept from being complicated.
According to a fourth aspect of the invention, in the liquefied gas storage tank, . the communication part in the third aspect may include a groove forming portion that ’ forms a grooved space. The communication part may further allow the upper 5 gaseous-phase region and the independent gaseous-phase generation region to communicate with each other via the groove forming portion.
Since the communication part is formed in a groove shape, the installation space of the communication part can be minimized. Therefore, a situation in which that tank capacity declines can be suppressed as much as the provision of the communication part.
According to a fifth aspect of the invention, in the liquefied gas storage tank, the communication part in the third aspect may include a tubular external pipe. The communication part may further allow the upper gaseous-phase region and the independent gaseous-phase generation region to communicate with each other via the external pipe.
By adopting such a configuration, the cost of parts can be reduced, and installation can be easily performed.
According to a sixth aspect of the invention, in the liquefied gas storage tank, the external pipe in the fifth aspect may include a displacement absorbing part that absorbs displacement of the position of the trunk top relative to the tank body.
By adopting such a configuration, even if the relative position of the tank body and the trunk top has been displaced due to rocking, inclining, or the like, this : displacement can be absorbed by the displacement absorbing part. Therefore, it is possible to suppress a situation in which the stress, acting on a coupling portion from the
0 tank body or the trunk top to which the communication part is connected, increases.
According to a seventh aspect of the invention, in the liquefied gas storage tank, ‘ the communication part in any one aspect of the first to sixth aspects may include a tubular internal pipe. The communication part may further allow the upper gaseous-phase region and the independent gaseous-phase generation region to communicate with cach other inside the tank body via the internal pipe. .
By adopting such a configuration, a space where the communication part is installed outside the tank body becomes unnecessary. Therefore, the workability of the communication part can be improved as compared to a case where the communication part is formed outside after the tank body is installed.
According to an eighth aspect of the invention, a vessel includes the liquefied gas storage tank according to any one of the first to seventh aspects.
By adopting such a configuration, even in a case where the gaseous phase is ; formed within the tank body due to inclining, rocking, or the like during navigation, the gaseous phase can be kept from being independently formed. Therefore, a decline in transport efficiency can be suppressed without lowering the stowage rate of the liquefied gas.
According to the above liquefied gas storage tank, the requirements specified in the "IGC Code" can be satisfied without lowering the stowage rate of the liquefied gas, and a decline in transport efficiency can be suppressed. Co
FIG. 1 is a view illustrating a schematic configuration of a vessel in a first embodiment of the invention.
FIG. 2 is a perspective view of a cargo tank in the first embodiment of the
S invention.
FIG. 3 is a top view of the cargo tank in the first embodiment of the invention.
FIG. 4 is a front view of the cargo tank in the first embodiment of the invention.
FIG. 5 is an explanatory view of an independent gas pocket formed in the cargo tank in a general vessel.
FIG. 6 is a front view equivalent to FIG. 4 in a modified example of the first embodiment of the invention.
FIG. 7 is an enlarged view of the vicinity of a trunk top of a cargo tank ina - second embodiment of the invention.
FIG. 8 is a perspective view of an external pipe in a modified example of the second embodiment of the invention.
FIG. 9 is an enlarged view equivalent to FIG. 7 in a third embodiment of the invention.
20 .
First Embodiment
Next, a vessel related to a first embodiment of the invention will be described with reference to the drawings.
FIG. 1 is a view illustrating a schematic configuration of the vessel in the first embodiment of the invention.
The vessel 1 of this embodiment is an LPG carrier that carries LPG (liquefied petroleum gas). The vessel 1 can store LPG in a cargo tank 3 (liquefied gas storage tank) in a state where LPG is cooled and liquefied and the volume thereof is made small, in order to carry more LPG. A heat insulating material is attached to an outer surface of the cargo tank 3.
As illustrated in FIG. 1, a plurality of cargo holds 4 are formed inside a hull 2 of the vessel 1. The cargo holds 4 are spaces that hold the cargo tanks 3, respectively.
The plurality of cargo holds 4 are provided side by side in a row in a bow-stern direction.
The cargo holds 4 adjacent to each other in the bow-stern direction are partitioned off in the bow-stern direction by partition walls 6. The cargo holds 4 in this embodiment are formed below an upper deck 5 of the hull 2. In FIG. 1, the bow-stern directions of the hull 2 are indicated by arrows, the direction of the bow is indicated by arrow "F", and the direction of a stern is indicated by arrow "A".
FIG. 2 is a perspective view of the cargo tank in the first embodiment of the invention. FIG. 3 is a top view of the cargo tank in the first embodiment of the oo invention. FIG. 4 is a front view in a state where the cargo tank inclines in the first embodiment of the invention.
As illustrated in FIGS. 2 to 4, the cargo tank 3 in this embodiment includes a i tank body 7, a trunk top 8, and a communication part 9.
The tank body 7 has therein a storage space 10 that stores liquefied gas. The : tank body 7 is a so-called rectangular tank of which a longitudinal section in a vessel width direction is formed in a polygonal box shape. The tank body 7 includes an upper wall 11, a bottom wall 12, a left side wall 13, a right side wall 14, a front wall 15, and a ”
rear wall 16. The tank body 7 in this embodiment further has four inclined walls 17 to 20 such that the four corners of the tank body 7 when viewed {from the bow-stern direction are chamfered. The tank body 7 forms the storage space 10, using the upper wall 11, the bottom wall 12, the left side wall 13, the right side wall 14, the front wall 15, the rear wall 16, and the inclined walls 17 to 20.
Here, a case where (he dimensions of the cargo tank 3 in the vessel width ) dircction arc constant is illustrated in FIGS. 1 and 2. However, the cargo tank 3 is not limited to the shape illustrated in FIGS. 1 and 2. In the vessel 1, the dimensions of the hull 2 in the vessel width direction vary depending on the bow and stern sides.
Moreover, the volume of the cargo tank 3 needs to be secured as large as possible within the cargo hold 4. Therefore, particularly the cargo tanks 3 arranged near the stern and near the bow of the hull 2 among the plurality of cargo tanks 3 are formed such that the left side wall 13 and the right side wall 14 incline or bend so as to resemble the shape of the vessel's sides of the hull 2. -
The trunk top 8 is formed so as to protrude upward from the tank body 7. The trunk top 8 in this embodiment protrudes from the upper wall 11 of the tank body 7.
The trunk top 8 has therein a convex space 21 that communicates with the storage space 10 of the tank body 7. The trunk top 8 in this embodiment is formed in a hollow rectangular parallelepiped shape. That is, the rectangular parallelepiped-shape convex space 21 is formed inside the trunk top. For example, the trunk top 8 is arranged such : that its upper end 8a protrudes further upward than the upper deck 5 of the hull 2. The liquefied gas G stored in the cargo tank 3 is loaded and unloaded via the trunk top 8.
A relief valve 23 (refer to FIG. 4) is arranged at the trunk top 8. The relief valve 23 is opened to thereby protect the cargo tank 3 when the internal pressure of the tank body 7 exceeds a predetermined pressure. As the relief valve 23 is opened, the gaseous phase of the convex space 21 is discharged to the outside of the tank body 7. }
The internal pressure of the tank body 7 drops due to the discharge of this gaseous phase.
Here, the stowage rate of liquefied gas G stored in the cargo tank 3 is a stowage rate (for example, about 98%) at which the relief valve 23 is not soaked in a liquid phase L. In other words, the constant gaseous phase V is always present in an upper part of the convex space 21 of the trunk top 8.
FIG. 5 is an explanatory view of an independent gas pocket formed in the cargo tank in a general vessel. -
As illustrated in FIG. 5, when the cargo stowage rate exceeds 98%, the cargo tank 3 having the trunk top 8 is inclined in the following requirement (a) specified in
International Code For The Construction And Equipment Of Ships Carrying Liquefied
Gases In Bulk (referred to as "IGC Code"). 1.5% Lpp trim (bow and stern) and 15 degree list (a)
Here, the "Lpp" is the length between bow-stern perpendicular lines of the vessel 1 on which the cargo tank 3 is mounted.
Co]
Then, for example, an independent gas pocket (gaseous phase) P may be generated within the storage space 10 of the cargo tank 3, due to various factors, such as rocking, inclining, and a temperature rise when the vessel 1 is navigating. Here, the "independent" means a state where the gas pocket P does not communicate with other atmospheres through gas. The "other atmospheres" means the gaseous phase V of the convex space 21 of the trunk top 8, the outside of the cargo tank 3, and the like.
The "IGC Code" prohibits the above-described independent gas pocket P from } being generated when the stowage rate of the liquefied gas G exceeds 98%.
As illustrated in FIGS. 2 to 4, the communication part 9 allows an upper gaseous-phase region of the convex space 21 where the gaseous phase V of the liquefied gas G 1s present to communicate with an independent gaseous-phase generation region of the storage space 10 where the independent gas pocket P can be generated from the gaseous phase V of the convex space 21. Here, the "independent gaseous-phase } generation region where the independent gas pocket P can be generated" means a region where the independent gas pocket P may be formed when there is no communication part 9. That is, the region is the "independent gaseous-phase generation region" even in a state where the gas pocket P is not formed. Although the "upper gaseous-phase region" changes its shape according to a direction (left or right) in which the hull 2 inclines, the gaseous phase V is always present. The communication part 9 disposed on the left side in the vessel width direction allows the upper gaseous-phase region and a left independent gaseous-phase generation region when the hull 2 has inclined to the right to py communicate with each other. Similarly, the communication part 9 disposed on the right side in the vessel width direction allows the upper gaseous-phase region and a right independent gaseous-phase generation region when the hull 2 has inclined to the left to communicate with each other.
In FIG 2, a boundary surface between a gaseous phase and a liquid phase of the liquefied gas G on the above-described condition (a) in a state where the cargo stowage : rate exceeds 98% is illustrated by shading. The independent gaseous-phase generation ;
region generated on the above-described condition (a) varies according to the shape of the cargo tank 3, the stowage rate of the liquefied gas G, or the like. This independent gaseous-phase generation region can be obtained, for example, through simulation or the like by determining the shape of the cargo tank 3 and determining a target value of the stowage rate of the liquefied gas G.
The communication part 9 in this embodiment allows the upper gaseous-phase region of the trunk top 8 and the independent gaseous-phase generation region of the tank body 7 to communicate with each other outside the storage space 10 of the tank body 7.
Moreover, the communication part 9 in this embodiment has a groove forming portion 24 that forms a grooved space. The communication part 9 has two groove forming portions 24. The upper gaseous-phase region of the trunk top 8 and the independent gaseous-phase generation region of the tank body 7 are enabled to communicate with each other via the grooved spaces that form the groove forming portions 24. )
The groove forming portions 24 in this embodiment extend outward in the vessel width direction from side surfaces 8b of the trunk top 8. The portions of the groove forming portions 24 on the tank body 7 side open toward the storage space 10.
Spaces formed by the groove forming portions 24 are formed in the shape of a groove as viewed from the inner side of the tank body 7. The groove forming portions 24 enable the gaseous phase V of the trunk top 8 and the gas pocket P of the tank body 7 to communicate with each other through the gaseous phase therein when the vessel 1 is ol inclined on the above-described condition (a). Here, the groove width of the groove forming portions 24 is only required to have the minimum dimensions for which the gaseous phase can be formed inside the groove forming portion. The length by which the groove forming portions 24 extend in the vessel width direction is only required to have the minimum length for which the groove forming portions reach the independent : gaseous-phase generation region from the trunk top 8. The height of the groove forming portions 24 are only required to become higher than an upper end of the liquid . level when the vessel is inclined on the condition (a).
A case where the above-described groove forming portions 24 extend in the vessel width direction has been described. However, the groove forming portions 24 are not limited to extending in the vessel width direction. For example, the groove forming portions 24 are only required to be appropriately selected according to the shape of the cargo tank 3, in the bow-stern direction, an intermediate direction between the bow-stern direction and the vessel width direction, or the like. In the above-described ’ embodiment, a case where the two groove forming portions 24 are provided has been described. However, three or more groove forming portions 24 may be provided. For example, as illustrated by two-dot chain lines in FIG. 3, the groove forming portion 24 may be radially arranged with the trunk top 8 as a center. The groove forming portions 24 illustrated by the two-dot chain lines in FIG. 3 are an example in which only directions in which the groove forming portions 24 extend are illustrated. Since the position of the independent gaseous-phase generation region varies according to the shape of the cargo tank 3, the length by which the groove forming portions 24 extend is set to an optimal position according to the position of the independent gaseous-phase generation region.
Here, positions with the highest probability that the gas pocket P is present, in : the storage space 10, are the positions of upper corners 7a formed by the upper wall 11 and the inclined walls 17 and 18 of the tank body 7. Therefore, forming the groove forming portions 24 from the trunk top 8 to the corners 7a is the surest way for performing this. However, in this case, the distance from the trunk top 8 becomes long. )
Therefore, it is neccessary to form the groove forming portions 24 to be longer, and this is disadvantageous with respect to cost or workability. Thus, in this embodiment, the independent gaseous-phase generation region is obtained through simulation or the like so as to connect the groove forming portions 24 to the independent gaseous-phase generation region, closer to the trunk top 8 side than the comers 7a.
Moreover, a case where the trunk top 8 in this embodiment is arranged at a central portion of the upper wall 11 in the bow-stern direction and the vessel width direction has been described as an example. However, the arrangement of the trunk top 8 in the bow-stern direction and the vessel width direction is not limited to the central portion. For example, the trunk top 8 may be arranged closer to the bow side or the stern side than the central portion. In this case, the groove forming portions 24 may be provided in consideration of the arrangement relationship between the trunk top 8 and the independent gaseous-phase generation region.
Therefore, according to the above-described first embodiment, the communication part 9 enables the upper gaseous-phase region present in the convex space 21 of the trunk top 8 and the independent gaseous-phase generation region of the storage space 10 of the tank body 7 to communicate with each other. Therefore, a situation in which the gas pocket P that can be generated in the storage space 10 of the tank body 7 becomes independent can be suppressed. As a result, the requirements specified in the "IGC Code" can be satisfied without lowering the stowage rate of the liquefied gas G. Accordingly, a decline in transport efficiency can be prevented. -
Moreover, the gaseous phase V is secured in the convex space 21 such that the relief valve 23 is not soaked in the liquid phase L in the convex space 21 of the trunk top 8. Therefore, even if the gas pocket P has been generated in the storage space 10 of the tank body 7, the communication part 9 allows the gaseous phase V of the convex space 21 and the gas pocket P of the storage space 10 to communicate with each other.
Therefore, if the relief valve 23 operates, the gas in the gas pocket P of the storage space ) can be relieved to the outside of the tank body 7. 10 Moreover, the communication part 9 can be easily added to the cargo tank 3 having the same shape as an existing cargo tank by providing the communication part 9 outside the tank body 7. Therefore, the design of the cargo tank 3 can be kept from being complicated.
Moreover, since the communication part 9 consists of the groove forming portions 24 formed in the shape of a groove, the installation space of the communication part 9 can be minimized. Therefore, the provision of the communication part 9 can keep the tank capacity of the cargo tank 3 from declining.
Modified Example of First Embodiment
FIG. 6 is a front view equivalent to FIG. 4 in a modified example of the first embodiment of the invention.
In the above-described first embodiment, a case where the groove forming Co portions 24 that constitute the communication part 9 are formed so as to have a rectangular parallelepiped shape has been described. However, the shape of the groove forming portions 24 is not limited to the rectangular parallelepiped shape. For example,
as illustrated in FIG. 6, the groove forming portions 24 may be formed in a triangular shape, as viewed from the bow-stern direction. Even when the groove forming portions 24 are formed in the triangular shape as viewed from the bow-stern direction in this way, similar to the groove forming portions 24 of the above-described first embodiment, the : gaseous phase V of the convex space 21 and the gas pocket P of the storage space 10 can be allowed to communicate with each other through the gaseous phase. When the groove forming portions 24 are formed in the rectangular parallelepiped shape as in the above-described first embodiment, this is advantageous in respect of facilitation of machining.
Second Embodiment
Next, a second embodiment of the invention will be described with reference to a drawing. This second embodiment is different from (he above-described first embodiment only in the shape of the communication part 9. Therefore, in the description of this second embodiment, the same portions as those of the first embodiment will be designated by the same reference numerals, and duplicate description will be omitted.
FIG. 7 is an enlarged view of the vicinity of a trunk top of a cargo tank in the second embodiment of the invention.
As illustrated in FIG. 7, a cargo tank 203 of this second embodiment includes the tank body 7, the trunk top 8, and a communication part 209.
The communication part 209, similar to the communication part 9 of the above-described first embodiment, allows the upper gaseous-phase region of the convex space 21, where the gaseous phase V of the liquefied gas G is present, to communicate with the independent gaseous-phase generation region in the storage space 10 where the } independent gas pocket P can be generated from the gaseous phase V of the convex space 21.
The communication part 209 in this embodiment is the same as the communication part 9 of the first embodiment in that the communication part 209 allows the upper gaseous-phase region of the trunk top 8 and the independent gaseous-phase generation region of the tank body 7 to communicate with each other outside the storage space 10 of the tank body 7. Co
The communication part 209 in this embodiment includes a tubular external pipe 224. Here, in FIG. 7, only one external pipe 224 among a plurality of the external pipes 224 is illustrated for the sake of convenience of illustration, and illustration of the other external pipes 224 is omitted (this also applies to FIG. 9). The communication part 209 allows the upper gaseous-phase region of the convex space 21 where the gaseous phase V is present to communicate with the independent gaseous-phase generation region of the storage space 10 where the gas pocket P can be generated, through the external pipes 224.
The external pipe 224 in this embodiment is parallel to the liquid level of the liquid phase L at the inclination of the above-described condition (a), and is linearly formed so as to connect the upper gaseous-phase region and the independent gaseous-phase generation region at the shortest distance. The aperture of the external pipes 224 is only required to have the minimum aperture such that gas can move between the gaseous phase V and the gas pocket P.
Here, although a case where the above-described external pipes 224 are installed parallel to the liquid level has been described, the installation angle of the external pipes 224 is not limited to the above-described installation angle. Moreover, the external pipes 224 are not limited to being linearly formed. For example, the external pipes 224 may be curvedly formed. ;
Moreover, the external pipes 224 are not limited to extending in the vessel width direction, similar to the above-described groove forming portions 24. For example, the external pipes 224 is only required to be appropriately selected according to the shape of the cargo tank 3, in the bow-stern direction, the intermediate direction between the bow-stern direction and the vessel width direction, or the like. Moreover, in the above-described second embodiment, a case where the two external pipes 224 are provided has been described. However, two or more external pipes 224 may be - provided. Similar to the above-described groove forming portions 24, the external pipes 224 may be radially arranged with the trunk top 8 as a center. Since the position of the independent gaseous-phase generation region varies according to the shape of the cargo tank 3, the length by which the external pipes 224 extend is set to an optimal position according to the position of the independent gaseous-phase generation region.
Therefore, according to the above-described second embodiment, the tubular external pipes 224 can constitute the communication part 209. Therefore, the cost of parts is reduced, and it is possible to easily perform installation.
Modified Example of Second Embodiment
FIG. 8 is a perspective view of an external pipe in a modified example of the second embodiment of the invention.
As illustrated in FIG. 8, an external pipe 224 of the communication part 209 in the modified example of this second embodiment includes a displacement absorbing part 30. The displacement absorbing part 30 absorbs the displacement of the trunk top 8 relative to the tank body 7.
More specifically, the external pipe 224 has the displacement absorbing part 30, which allows a trunk top connecting pipe 31 and a tank body connecting pipe 32 to communicate with each other, between the trunk top connecting pipe 31 and the tank body connecting pipe 32. .
The trunk top connecting pipe 31 extends in the vessel width direction from the side surface 8b of the trunk top 8. An end (not illustrated) of the trunk top connecting pipe 31 opens in the gaseous phase V of the above-described convex space 21.
Therefore, the trunk top connecting pipe 31 is arranged apart from the upper wall 11 of the tank body 7.
The tank body connecting pipe 32 extends in the vessel width direction (a direction illustrated by a left arrow and a right arrow among FIG. 8) along the upper wall - 11 of the tank body 7. An end of the tank body connecting pipe 32 extends downward (the direction illustrated by the lower arrow among FIG. 8) so as to be bent. The end of the tank body connecting pipe 32 opens to the independent gaseous-phase generation region of the storage space 10 of the above-described tank body 7. The tank body connecting pipe 32 is arranged so as to be offset from the above-described trunk top connecting pipe 31 in a vertical direction (a direction illustrated by an upper arrow and a lower arrow in FIG. 8). In FIG. 8, the bow-stern direction is a direction illustrated by a : front arrow and a rear arrow.
The displacement absorbing part 30 allows the trunk top connecting pipe 31 and the tank body connecting pipe 32 to communicate with each other. The displacement absorbing part 30 has a horizontal portion 33 and a vertical portion 34. The horizontal portion 33 extends so as to intersect the trunk top connecting pipe 31 in the bow-stern direction. The vertical portion 34 extends so as to intersect both the horizontal portion 33 and the tank body connecting pipe 32 in the vertical direction. )
Therefore, according to the modified example of the above-described second embodiment, the horizontal portion 33 easily bends in the vertical direction and the vessel width direction with respect to the trunk top connecting pipe 31, and the vertical portion 34 easily bends in the bow-stern direction and the vessel width direction with respect to the tank body connecting pipe 32. The relative displacement of the trunk top 8 and the tank body 7 in the bow-stern direction, the vessel width direction, and the vertical direction can be absorbed by virtue of the bending. As a result, a situation in which the stress caused by the above relative displacement acts on the tank body 7 or the trunk top 8 can be suppressed more than in a case where the external pipes 224 are linearly provided between the trunk top 8 and the tank body 7.
Third Embodiment
Next, a third embodiment of the invention will be described with reference to a drawing. This third embodiment is different from the above-described second embodiment in the arrangement of a pipe. Therefore, the same portions as those in the second embodiment will be designated by the same reference numerals, and duplicate description will be omitted.
FIG. 9 is an enlarged view equivalent to FIG. 7 in the third embodiment of the invention.
As illustrated in FIG. 9, the communication part 209 in this third embodiment has an internal pipe 324. The internal pipe 324 enables the upper gaseous-phase region . of the convex space 21 where the gaseous phase V is present to communicate with the independent gaseous-phase generation region of the storage space 10 where the gas pocket P is present.
The internal pipe 324 is formed in a tubular shape. The internal pipe 324 is completely disposed inside the cargo tank 303. The internal pipe 324 is formed so as to extend along the side surface 8b of the trunk top 8 and the upper wall 11 of the tank body 7 and s0 as to be bent in an L-shape in correspondence with a corner 36 formed by the ’ side surface 8b and the upper wall 11. The internal pipe 324 is fixed to a plurality of ribs 37 that protrude inward from an inner surface of the cargo tank 3. The internal pipe 324 is spaced apart from an inner surface 3a of the cargo tank 3 by being fixed to the ribs 37 in this way. When the internal pipe 324 inclines on the above-described condition (a), a first end 324a thereof opens within the gaseous phase V. Moreover, when the internal pipe 324 inclines on the above-described condition (a) and the gas pocket P is formed in the independent gaseous-phase generation region, a second end 324b thereof opens within the gas pocket P. That is, the internal pipe 324 enables the gaseous phase )
V and the gas pocket P to communicate with each other.
Therefore, according to the above-described third embodiment, a space where the communication part 9 is installed outside the tank body 7 becomes unnecessary.
Therefore, the workability of the communication part 9 can be improved as compared to a case where the communication part 9 is formed outside afier the tank body 7 is } installed.
For example, in the above-described embodiments, a case where the independent cargo tank 3, 203, or 303 having a gap between the cargo tank 3, 203, 303 and the hull 2 is provided has been described as an example. However, the shape of the cargo tank 3, 203, or 303 is not limited to the shape of the above-described cargo tank 3, 203,0r303. As long as a shape in which the trunk top 8 protrudes upward is provided, for example, the tank body 7 of the cargo tank 3, 203, or 303 may be formed integrally oo with the hull 2. Moreover, the tank body 7 of the cargo tank 3, 203, or 303 are only required to provide a shape that can have the independent gaseous-phase generation region when the stowage rate is equal to or more than 98% and the above-described condition (a) is described, and may be, for example, a spherical shape. Moreover, the shape of the tank body 7 may be a shape having a combination of a spherical shape and at least one of a toroidal surface, a cylindrical surface, a conical surface, which are modified shapes of a spherical shape.
Moreover, a case where the vessel 1 of the above-described embodiment is an
LPG carrier has been described as an example. However, what the vessel 1 stores and carries in the cargo tank 3, 203, or 303 is not limited to LPG. Liquefied natural gas (LNG) or the like may be used.
While preferred embodiments of the invention have been described and illustrated above, it should be understood that these are exemplary of the invention and are not to be considered as limiting. Additions, omissions, substitutions, and other } modifications can be made without departing from the spirit or scope of the present invention. Accordingly, the invention is not to be considered as being limited by the foregoing description, and is only limited by the scope of the appended claims.
EXPLANATION OF REFERENCES
[0056] 1: VESSEL Co 2: HULL 3,203,303: CARGO TANK (LIQUEFIED GAS STORAGE TANK) 3a: INNER SURFACE 4: CARGO HOLD 5: UPPER DECK 6: PARTITION WALL 7: TANK BODY 7a: CORNER oo 8: TRUNK TOP 8a: UPPER END 8b: SIDE SURFACE ] 9: COMMUNICATION PART 10: STORAGE SPACE 11: UPPER WALL 12: BOTTOM WALL 13: LEFT SIDE WALL - 14: RIGHT SIDE WALL
1S: FRONT WALL 16: REAR WALL 17: INCLINED WALL 18: INCLINED WALL 19: INCLINED WALL 20: INCLINED WALL 21: CONVEX SPACE 23: RELIEF VALVE 24: GROOVE FORMING PORTION 30: DISPLACEMENT ABSORBING PART 31: TRUNK TOP CONNECTING PIPE 32: TANK BODY CONNECTING PIPE 33: HORIZONTAL PORTION 34: VERTICAL PORTION oo 36: CORNER 37. RIB 209: COMMUNICATION PART 224: EXTERNAL PIPE © 324: INTERNAL PIPE
Claims (8)
1. Aliquefied gas storage tank comprising: a tank body having therein a storage space that stores liquefied gas; a trunk top that protrudes upward from the tank body and has therein a convex space that communicates with the storage space; and a communication part that allows an upper gaseous-phase region of the convex space where a gaseous phase of the liquefied gas is present to communicate with an independent gaseous-phase generation region of the storage space where a gaseous phase, which is independent from the gaseous phase of the convex space, capable of being generated. -
2. The liquefied gas storage tank according to Claim 1, further comprising: a relief valve capable of discharging the gaseous phase of the convex space to the outside of the tank body when a pressure of the inside of the tank body exceeds a predetermined pressure.
3. The liquefied gas storage tank according to Claim 1, wherein the communication part allows the upper gaseous-phase region and the - independent gaseous-phase generation region to communicate with each other outside the tank body.
4. The liquefied gas storage tank according to Claim 3, wherein the communication part includes a groove forming portion that forms a grooved space, and allows the upper gaseous-phase region and the independent gascous-phase generation region to communicate with cach other via the groove forming portion.
5. The liquefied gas storage tank according to Claim 3, wherein the communication part includes a tubular external pipe, and allows the upper gaseous-phase region and the independent gaseous-phase generation region to communicate with each other via the external pipe.
6. The liquefied gas storage tank according to Claim 5, wherein the external pipe includes a displacement absorbing part that absorbs displacement of the position of the trunk top relative to the tank body.
7. The liquefied gas storage tank according to Claim 1, wherein the communication part includes a tubular internal pipe, and allows the upper gaseous-phase region and the independent gaseous-phase generation region to communicate with each other inside the tank body via the internal pipe. .
8. Avessel comprising: the liquefied gas storage tank according to any one of Claims 1 to 7.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2015067246A JP6299037B2 (en) | 2015-03-27 | 2015-03-27 | Liquefied gas storage tank and ship |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| PH12015000369A1 PH12015000369A1 (en) | 2017-05-08 |
| PH12015000369B1 true PH12015000369B1 (en) | 2017-05-08 |
Family
ID=57082622
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PH12015000369A PH12015000369B1 (en) | 2015-03-27 | 2015-10-27 | Liquefied gas storage tank and vessel |
Country Status (4)
| Country | Link |
|---|---|
| JP (1) | JP6299037B2 (en) |
| KR (1) | KR101766044B1 (en) |
| CN (1) | CN106005271B (en) |
| PH (1) | PH12015000369B1 (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106764401A (en) * | 2017-02-24 | 2017-05-31 | 江苏宏博机械制造有限公司 | A kind of lightweight high intensity pressure resistant type pressure pan |
| JP2019039440A (en) * | 2017-08-22 | 2019-03-14 | 三井Ｅ＆Ｓ造船株式会社 | Liquefied gas storage tank structure, floating structure, and release method for internal pressure of storage tank |
| WO2021194250A1 (en) * | 2020-03-26 | 2021-09-30 | 삼성중공업 주식회사 | Liquefied gas storage tank system, and design and manufacturing methods therefor |
| JP2021160619A (en) * | 2020-04-01 | 2021-10-11 | 川崎重工業株式会社 | Ship |
| CN113212664A (en) * | 2021-06-09 | 2021-08-06 | 江南造船(集团)有限责任公司 | Air chamber communication structure and liquefied gas carrier of C type fluid reservoir |
Family Cites Families (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5649699U (en) * | 1979-09-25 | 1981-05-01 | ||
| JPS59164286A (en) * | 1983-03-10 | 1984-09-17 | Tounen Tanker Kk | Recovering apparatus for gas in cargo tank of ship |
| JPH03124100U (en) * | 1990-03-29 | 1991-12-17 | ||
| JPH08310482A (en) * | 1995-05-18 | 1996-11-26 | Hitachi Zosen Corp | Substitute gas feeding part structure of storage tank in transport ship |
| US6637469B2 (en) * | 2002-03-19 | 2003-10-28 | Air Products And Chemicals, Inc. | Product delivery system for stationary or portable bulk containers |
| KR100971895B1 (en) * | 2003-07-17 | 2010-07-23 | 사우디 아라비안 오일 컴퍼니 | A marine vessel and a gas expansion trunk for the marine vessel |
| KR100805022B1 (en) * | 2007-02-12 | 2008-02-20 | 대우조선해양 주식회사 | Lng cargo tank of lng carrier and method for treating boil-off gas using the same |
| JP4562201B2 (en) * | 2007-10-24 | 2010-10-13 | ツネイシホールディングス株式会社 | Air vent pipe |
| JP2009119903A (en) * | 2007-11-12 | 2009-06-04 | Universal Shipbuilding Corp | Air vent device of fuel tank and marine vessel |
| JP5148319B2 (en) * | 2008-02-27 | 2013-02-20 | 三菱重工業株式会社 | Liquefied gas reliquefaction apparatus, liquefied gas storage equipment and liquefied gas carrier equipped with the same, and liquefied gas reliquefaction method |
| JP5806391B2 (en) * | 2011-05-25 | 2015-11-10 | サムスン ヘビー インダストリーズ カンパニー リミテッド | Liquefaction storage tank and ship including the same |
| JP5715699B2 (en) * | 2011-08-13 | 2015-05-13 | 信吉 森元 | LNG ship |
-
2015
- 2015-03-27 JP JP2015067246A patent/JP6299037B2/en active Active
- 2015-10-08 KR KR1020150141575A patent/KR101766044B1/en active IP Right Grant
- 2015-10-27 PH PH12015000369A patent/PH12015000369B1/en unknown
- 2015-10-28 CN CN201510713161.XA patent/CN106005271B/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CN106005271B (en) | 2018-05-22 |
| JP2016185780A (en) | 2016-10-27 |
| KR20160115660A (en) | 2016-10-06 |
| PH12015000369A1 (en) | 2017-05-08 |
| JP6299037B2 (en) | 2018-03-28 |
| KR101766044B1 (en) | 2017-08-07 |
| CN106005271A (en) | 2016-10-12 |
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