CN114286780A

CN114286780A - Floating structure

Info

Publication number: CN114286780A
Application number: CN201980099835.8A
Authority: CN
Inventors: 金山维史; 岸本直彦; 谷川圭史
Original assignee: Nikkei Global Co ltd
Current assignee: Nikkei Global Co ltd
Priority date: 2019-12-06
Filing date: 2019-12-06
Publication date: 2022-04-05
Also published as: WO2021111623A1

Abstract

[ problem ] to provide a floating structure that can be built at low cost and in a short delivery period. [ MEANS FOR solving PROBLEMS ] A floating structure of the present invention is a liquefied gas carrier ship which is modified from a ship body part having a thin-film or self-supporting ridge-shaped storage tank mounted thereon, and comprises: the hull portion; a protruding portion fixed to the hull portion and protruding toward at least one side in a width direction of the hull portion; and a gas processing device disposed on the extension, the extension and the gas processing device being added when retrofitting.

Description

Floating structure

Technical Field

The present invention relates to a floating structure obtained by modifying an existing Liquefied Natural Gas (LNG) carrier.

Background

In addition to natural gas processing facilities for processing natural gas, floating structures have been known which include LNG tanks for storing liquefied natural gas. As a method of constructing the floating structure, first, a new construction is considered, but in addition to the new construction, a method of using an existing LNG carrier or the like is also considered.

As a method of using a conventional LNG carrier, for example, a technique of transferring an LNG tank from an aged LNG carrier and reusing the LNG tank to construct a new floating structure has been proposed (for example, see patent document 1). The technique focuses on the following properties: even if the hull of the conventional LNG carrier is deteriorated, the LNG tank is not deteriorated because the liquefied natural gas stored therein is not corrosive.

According to the above-described technology, the LNG tank of the conventional LNG carrier is reused, and thus, it is not necessary to newly construct the LNG tank, so that the construction process of a new floating structure can be significantly shortened, and the cost can be reduced.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open No. 2012-86768

Disclosure of Invention

Problems to be solved by the invention

However, when an aged LNG carrier is transferred to an LNG tank to construct a new floating structure as in the above-described technique, a hull portion of the floating structure needs to be newly constructed. Therefore, even if the conventional LNG tank is reused, the hull portion requires a conventional construction process and cost, and the construction period and cost reduction effect are insufficient.

In this case, it is also considered that the LNG carrier is directly used for a floating structure, but there is a problem that a space for mounting the natural gas treatment facility cannot be secured.

The invention aims to provide a floating structure which can be built at low cost and in a short delivery period.

Means for solving the problems

The floating structure of the present invention is a liquefied gas carrier ship which is formed by reforming a ship body part having a film-type or self-supporting ridge-type storage tank, and includes:

the hull portion;

a protruding portion fixed to the hull portion and protruding toward at least one side in a width direction of the hull portion; and

and a gas processing device disposed on the extension portion.

In the floating structure of the present invention, the extension portion and the gas processing device are parts that are added at the time of modification.

As described above, by directly using the conventional liquefied gas carrier and additionally providing the extension portion and the gas treatment facility, the floating structure can be constructed at low cost and in a short delivery period. In addition, by providing the extension portion, a space for disposing the gas processing apparatus can be sufficiently secured.

In the floating structure of the present invention,

the gas treatment device includes a module.

As mentioned above, the gas treatment plant may also comprise modules.

In the floating structure of the present invention,

the module includes a projection projecting toward the hull portion.

As described above, the module is projected toward the hull portion, whereby the space above the hull portion can be effectively used.

In the floating structure of the present invention,

the hull portion includes: a lower hull portion to which the extension portion is fixed; and

an upper hull portion protruding above the lower hull portion and forming an upper portion of the storage tank,

the upper hull portion includes a hull inclined portion inclined downward toward the lower hull portion at an end portion in the width direction of the upper hull portion,

the protruding part protrudes toward the upper hull part,

a module inclined portion is formed below the protruding portion, and the module inclined portion is inclined upward along the hull inclined portion.

As described above, by forming the module inclined portion below the protruding portion, the module can be protruded along the hull inclined portion of the upper hull portion, and the module can be used without wasting the space of the inclined portion of the upper hull portion.

Further, the floating structure of the present invention

Includes a plurality of posts supporting the module,

all the pillars are disposed on the protruding portion.

That is, the module is disposed on the pillar in the protruding portion. Therefore, the protruding part can be designed in advance in a manner of having strength to support the module, without requiring a reinforcement work for supporting the hull part of the module.

Further, the floating structure of the present invention

Includes a plurality of posts supporting the module,

a part of the struts is disposed on the hull portion, and the rest of the struts is disposed on the extension portion.

That is, according to the above configuration, the load of the module can be distributed to the hull portion and the protruding portion, and therefore the module can be stably supported with good balance. Further, since a part of the weight of the module can be supported by the hull portion, the strength of the extension portion itself and the fixing strength to the hull portion can be reduced, and the construction cost of the extension portion can be reduced.

In the floating structure of the present invention,

the strut on the hull portion side is disposed on a side outer plate constituting a side of the hull portion.

This allows the load applied to the strut to be transmitted to the side outer plate having a higher strength than the other portions, thereby firmly supporting the strut.

In the floating structure of the present invention,

the module is formed across the storage tank in a width direction of the hull portion.

This enables effective use of the hollow space above the tank.

Further, a floating structure according to the present invention is a liquefied gas carrier ship which is a ship body including a thin-film or self-supporting ridge-shaped storage tank, the floating structure including:

the hull portion; and

and a module constituting a gas treatment apparatus.

In the floating structure of the present invention, the modules are supported by struts arranged on both sides of the tank in the width direction of the hull and arranged above the tank,

the modules are added as rebuilds.

As described above, by providing the strut on the hull portion and disposing the module thereon, the module can be disposed in the space above the hull portion. Therefore, the cost and the workload for modifying the conventional liquefied gas carrier can be greatly reduced.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, a floating structure that can be constructed at low cost and in a short delivery period can be provided.

Drawings

Fig. 1 is a schematic view of a floating structure according to an embodiment as viewed from above.

Fig. 2 is a schematic view of the floating structure of the embodiment as viewed from the front.

Fig. 3 is a diagram illustrating a method of constructing a floating structure according to an embodiment.

Fig. 4 is a diagram illustrating a case where a module is mounted on an extension portion added to the floating structure according to the embodiment.

Fig. 5 is a schematic view of a floating structure according to another embodiment as viewed from the front.

Fig. 6 is a schematic view of a floating structure according to another embodiment as viewed from the front.

Fig. 7 is a schematic view of a floating structure according to another embodiment as viewed from the front.

Detailed Description

Hereinafter, a floating structure according to an embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a schematic view of a floating structure 2 according to an embodiment as viewed from above, and fig. 2 is a schematic view of the floating structure as viewed from the front (in the direction of arrow a shown in fig. 1). As shown in fig. 1 and 2, the floating structure 2 is a structure that is long in one direction and mainly includes a hull portion 4 called a hull (hull). The floating structure 2 according to the embodiment is obtained by modifying an LNG carrier 26 (see fig. 3) which is a conventional liquefied gas carrier.

The floating structure 2 is used as an offshore facility. As such facilities, floating production storage and shipping (FPSO) facilities that produce, store, and ship oil, natural gas, and the like, floating storage and shipping (FSO) facilities that do not include production facilities and do only store and ship, floating storage and shipping (FSU) facilities that do only store, and the like are known. As one of FPSOs, Floating Liquefied Natural Gas (FLNG) facilities specialized for production, storage, and shipment of Liquefied Natural Gas (LNG) are known. In the embodiment of the present invention, a case where the floating structure 2 is FLNG will be described as an example. The floating structure 2 does not have a self-propulsion function, and is towed by a power boat when moving.

In the floating structure 2, the hull portion 4 of the conventional LNG carrier 26 (see fig. 3) is used as the hull portion 4. The hull portion 4 includes ballast tanks 10 on the inner sides of the ship side 8 and the ship bottom 9, and the ballast tanks 10 are spaces into which seawater or the like is filled in order to adjust the weight of the hull portion 4 and balance the hull portion 4. A tank 12 for storing liquefied natural gas is mounted on the hull portion 4.

Here, The type of storage tank 12 is specified by International Code of The Construction and Equipment rules for Bulk transport Liquefied gas vessels in Bulk, IGC Code, issued by The International Maritime Organization (IMO). As specific types, the following are known: a spherical type called the Moss (Moss) type; a ridge type, called a Membrane (Membrane) type, which is integrated with a hull by attaching a thin-film tank material inside the hull; the hull and the prismatic tank are respectively independent of self-supporting prismatic type, etc.

In the present embodiment, the thin-film type tank 12 is described as an example, but the tank 12 may be a self-supporting ridge type. In the present embodiment, the tank 12 having the octagonal cross-sectional shape is exemplified, but the tank 12 is not limited to the octagonal shape as long as it has a non-spherical shape.

The hull portion 4 includes a lower hull portion 41 that houses the storage tank 12, and an upper hull portion 18 that protrudes above the lower hull portion 41 and constitutes an upper portion of the storage tank 12. Further, the lower hull part 41 includes a side outer plate 40 constituting an outer shell of the ship side 8 and a bottom outer plate 42 constituting an outer shell of the ship bottom 9. The upper hull 18 includes hull inclined portions 18a inclined downward toward the lower hull 41 at both ends in the width direction of the upper hull 18. That is, the periphery of the upper hull 18 is inclined downward in accordance with the inclined portion of the upper end of the tank 12. Further, the width direction of the upper hull portion 18 coincides with the width direction of the hull portion 4.

Extensions 14, which are called pontoons or floating wings (sponson), and which extend outward of the hull portion 4, are fixed to both sides of the hull portion 4 in the width direction. In the present embodiment, the extension portion 14 is fixed to the lower hull portion 41. A waste oil tank, an additional ballast tank, and the like are provided inside the extension portion 14. In addition, the space above the module 16, which will be described later, is not disposed on the extension portion 14 and is used as a place where a device is placed.

Further, a gas treatment facility for treating gas is disposed in the extension portion 14. In the present embodiment, a natural gas processing facility is disposed as a gas processing facility in the extension portion 14. Specifically, a module 16 serving as a natural gas processing facility is disposed on the extension 14. The module 16 is a structure on which equipment or piping for processing natural gas is mounted. After the modules 16 are set on the extension portions 14, the facilities and pipes in the adjacent modules 16 are connected to each other as necessary to constitute a natural gas processing facility.

The module 16 is supported by a pillar 17 called a pier (stool) disposed on the extension portion 14. The struts 17 include a first strut 17a located on the hull portion 4 side in the width direction of the hull portion 4 and a second strut 17b located on the opposite side to the hull portion 4 side. The first and

second struts

17a and 17b are arranged in a row at a predetermined interval along the longitudinal direction of the hull 4. In the present embodiment, the extension portion 14, and the module 16 and the strut 17 (the first strut 17a and the second strut 17b) as the natural gas processing apparatus are included in an added part described below.

Here, the module 16 includes a projection 16a projecting toward the hull portion 4. A module inclined portion 16b inclined upward toward the hull portion 4 is formed below the protruding portion 16 a. In the present embodiment, the protruding portion 16a protrudes toward the upper hull portion 18, and the module inclined portion 16b is inclined upward along the hull inclined portion 18a of the upper hull portion 18.

As described above, by projecting the modules 16 toward the hull portion 4 side, the space above the hull portion 4 can be effectively used. Further, by forming the module inclined portion 16b below the module 16, the module 16 can be made to protrude in accordance with the hull inclined portion 18a of the upper hull portion 18, and the space for the inclination of the hull inclined portion 18a of the upper hull portion 18 can be utilized without wasting it.

In addition, a living area 20 including a crew room, a kitchen, and the like is disposed on the floating structure 2.

Next, an example of a method for constructing the floating structure 2 according to the embodiment will be described. First, the LNG carrier 26 on which the thin film type or self-supporting ridge type storage tank 12 is mounted is towed by a tow vessel such as a tug boat, and enters the dock 24 as shown in fig. 3 (a). Next, as shown in fig. 3(b), the seawater in the dock 24 is discharged to land the LNG carrier 26 on the dock floor. Then, the overhang portions 14 are carried into both sides of the hull portion 4 of the LNG carrier 26 in the width direction. Then, the extension portion 14 is welded to the hull portion 4, thereby building up the extension portion 14 in the hull portion 4 as shown in fig. 3 (c).

After the extension portion 14 is built, a support column 17 is disposed on the extension portion 14, and the module 16 is usually mounted thereon by a crane. As an alternative to the mounting method, as shown in fig. 4(a), a guide rail 29 for transferring the module 16 is provided on the column 17. With the modules 16 being properly carried into the dock 24. The module 16 is transferred to the lifter 30 disposed in the vicinity of the dock 24, and then, as shown in fig. 4(b), the lifter 30 is raised to the same level as the guide rail 29.

Then, the module 16 is moved from the lifter 30 to the guide rail 29, whereby the module 16 is mounted on the projecting portion 14 as shown in fig. 4 (c). This transfer process is called jack-up and slipping, and is sometimes used as one of the module mounting methods. This completes the conversion of the LNG carrier 26, and completes the floating structure 2 obtained by converting the LNG carrier 26. Then, the dock 24 is filled with water, and the floating structure 2 is pulled to a destination by a tow boat after being supplied with water and being undocked. The processing of the natural gas is performed at the destination.

In the floating structure 2 constructed in the above manner, a known pretreatment for removing impurities from natural gas in a natural gas processing facility and a known liquefaction process for liquefying the pretreated natural gas are performed.

According to the invention of the present embodiment, the floating structure 2 can be constructed at low cost and in a short delivery period by building the extension portions 14, the modules 16, and the like, directly using the existing LNG carrier. Further, by providing the extension portion 14, a sufficient space for disposing the module 16 can be secured.

Further, since all the struts 17 of the first strut 17a and the second strut 17b are disposed on the extension portion 14, the extension portion 14 can be designed to have the strength to support the module 16 in advance, and a reinforcement work for supporting the hull portion 4 of the module 16 is not required. In addition, even in the case where the reinforcement work of the projecting portion 14 on the hull portion 4 side is required, the strut 17 (first strut 17a) does not cause an obstacle. This makes it possible to easily perform the reinforcement process.

In the above embodiment, the case where both the first strut 17a and the second strut 17b are disposed on the extension portion 14 in the width direction of the hull portion 4 is described as an example, but the first strut 17a may be disposed on the hull portion 4 as shown in fig. 5. That is, a part of the strut 17 may be disposed on the hull portion 4. This makes it possible to distribute the load of the module 16 to the hull portion 4 and the extension portion 14, and thus to stably support the module 16 with good balance. Further, since a part of the weight of the module 16 can be supported by the hull portion 4, the strength of the extension portion 14 itself and the fixing strength to the hull portion 4 can be reduced, and the construction cost of the extension portion 14 can be reduced. Further, the distance between the struts 17 in the width direction of the hull portion 4 is increased, and therefore the module 16 can be stably supported.

In this case, the first support column 17a is disposed on the side outer plate 40 constituting the ship side 8 of the hull portion 4. The side outer panel 40 has a higher strength than a portion where the storage tank 12 is provided. Therefore, the load received by the first strut 17a can be directly transmitted to the side outer panel 40, and the first strut 17a can be firmly supported.

In the above embodiment, as shown in fig. 2, the modules 16 are disposed above the extension portions 14 on both sides of the hull portion 4 in the width direction. The modules 16 may be formed across the tanks 12 in the width direction of the hull portion 4. For example, as shown in FIG. 6, modules 16 disposed above the extensions 14 may be connected above the storage tank 12. This also makes it possible to effectively utilize the space above the tank 12.

In the case where the module 16 is disposed above the tank 12 as described above, the struts 17 may be disposed on both sides of the tank 12 in the width direction of the hull 4 without providing the extension portions 14, as shown in fig. 7. In this case, it is preferable that the support columns 17 be provided on the side outer panels 40, and the modules 16 be supported by the support columns 17 disposed on both sides of the storage tank 12.

That is, when there is a small space in the hull portion 4 where the tanks 12 are not disposed, the module 16 can be disposed without providing the extension portions 14 by disposing the struts 17 directly on the hull portion 4 as described above. Therefore, the module 16 can be installed in the space above the hull 4, and the cost and the workload for modifying the conventional LNG carrier 26 can be significantly reduced.

In the above embodiment, the case where the extension portions 14 are provided on both sides of the hull portion 4 has been described as an example, but the extension portions 14 may be provided only on one side of the hull portion 4.

In the above embodiment, the first support column 17a and the second support column 17b are shown as being arranged in a line at a specific interval along the longitudinal direction of the hull portion 4, but the support columns 17 are not necessarily arranged as described above. For example, the strut 17 may be disposed without distinguishing the first strut 17a from the second strut 17 b.

In the above embodiment, the case where the module 16 is a natural gas processing facility is exemplified, but the module 16 may include a facility other than a natural gas processing facility.

In the above embodiment, the floating structure 2 having no self-propulsion function is described as an example, but the moving method of the floating structure 2 is not particularly limited, and the floating structure 2 may have a self-propulsion function.

In addition, although not particularly mentioned in the above embodiment, the module 16 may include a high temperature module provided with a machine for pretreating natural gas before liquefaction and a low temperature module provided with a machine for liquefying natural gas. In this case, the high temperature module may be disposed on one side of the hull portion 4 in the width direction, and the low temperature module may be disposed on the other side. Alternatively, two systems of low-temperature modules may be provided, and one system may be disposed on each side of the storage tank 12.

In addition, although not particularly mentioned in the above embodiment, the module inclined portion 16b may have a shape that is inclined as a whole by a step, for example, as long as it can be arranged along the hull inclined portion 18 a. In short, the module inclined portion 16b may have a shape that enables the dead space to be effectively utilized by being disposed along the hull inclined portion 18 a.

Description of the symbols

2: floating structure

4: ship body part

8: ship side

10: ballast tank

12: storage tank

14: extension part

16: module

16 a: projection part

16 b: module rake

17: support post

17 a: first strut

17 b: second support

18: go up hull part

18 a: inclined part of ship body

20: residential area

24: dock

26: carrying ship

28: space(s)

29: guide rail

30: elevator machine

40: side outer plate of ship

41: lower hull part

42: ship bottom outer plate

Claims

1. A floating structure, which is obtained by modifying a liquefied gas carrier vessel including a vessel body part on which a film-type or self-supporting ridge-type storage tank is mounted, the floating structure comprising:

the hull portion;

a gas processing device disposed on the extension portion,

the extension and the gas processing apparatus are added when retrofitting.

2. The floating structure according to claim 1, wherein

The gas treatment device includes a module.

3. The floating structure according to claim 2, wherein

The module includes a projection projecting toward the hull portion.

4. The floating structure according to claim 3, wherein

the protruding part protrudes toward the upper hull part,

5. The floating structure according to any one of claims 2 to 4, comprising:

a plurality of support posts supporting the modules,

all the pillars are disposed on the protruding portion.

6. The floating structure according to any one of claims 2 to 4, comprising:

a plurality of support posts supporting the modules,

7. The floating structure according to claim 6, wherein

The strut on the hull portion is disposed on a side outer panel constituting a side of the hull portion.

8. The floating structure according to any one of claims 2 to 7, wherein

9. A floating structure, which is obtained by modifying a liquefied gas carrier vessel including a vessel body part on which a film-type or self-supporting ridge-type storage tank is mounted, the floating structure comprising:

the hull portion;

the module, which constitutes a gas treatment apparatus,

the modules are supported by struts arranged on both sides of the tank in the width direction of the hull, and arranged above the tank,

the modules are added as rebuilds.