LNG SHIP

Abstract

To obtain an economical hull structure by employing an independent prismatic tank having a large tank volume with respect to a ship size and reducing material cost.

Provided is a LNG ship having a structure in which a substantially prismatic tank is installed inside a hold while not being integrated with a hull structure material, wherein a tank bottom surface is provided with inclined surfaces formed at the left and right sides of a center line direction of the ship as a boundary so that each angle intersecting a horizontal line becomes equal to or smaller than 4.0°, and support bodies integrated with the hull structure material are arranged so as to correspond to the inclined surfaces and the tank is put on the support bodies.

Claims

1. A LNG ship having a structure in which a substantially prismatic tank is installed inside a hold while not being integrated with a hull structure material, wherein a tank bottom surface is provided with inclined surfaces formed at the left and right sides of a center line direction of the ship as a boundary so that each angle intersecting a horizontal line becomes equal to or smaller than 4.0°, and support bodies integrated with the hull structure material are arranged so as to correspond to the inclined surfaces and the tank is put on the support bodies.

2. The LNG ship according to claim 1, wherein a flat surface is formed at a center portion of the tank bottom surface, a receiving body integrated with the hull structure material is provided so as to correspond to the flat surface, and the flat surface is installed on the receiving body.

3. The LNG ship according to claim 1, wherein the support bodies are arranged at the left and right sides of the center line direction of the ship as the boundary so as to be located at a plurality of positions separated from each other in a ship width direction.

4. The LNG ship according to claim 1, wherein the support bodies are arranged at the left and right sides of the center line direction of the ship as the boundary so as to be located at a plurality of positions separated from each other in a ship width direction and are provided along a ship longitudinal direction.

5. The LNG ship according to claim 1, wherein the support bodies are arranged at the left and right sides of the center line direction of the ship as the boundary so as to be located at a plurality of positions in a zigzag pattern.

6. The LNG ship according to claim 1, wherein a key portion is integrally formed with a center upper portion of the tank in a protruding manner and anchor point chocks are provided in the hull structure material so as to be located at front and rear sides in the center line direction of the ship corresponding to the key portion.

7. The LNG ship according to claim 1, wherein a material of the prismatic tank is selected from aluminum alloy, 9% nickel steel, and stainless steel.

8. The LNG ship according to claim 1, wherein the LNG ship includes a LNG carrier, FLNG, FSRU, and SRV.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0055] FIG. 1 is a front view of a LNG ship.

[0056] FIG. 2 is a plane view of the LNG ship.

[0057] FIG. 3 is a cross-sectional view of the LNG ship.

[0058] FIG. 4 is a view taken along the line 4-4.

[0059] FIG. 5 is a partial plane view of another arrangement example of support bodies.

[0060] FIG. 6 is a cross-sectional view of another shape example of a tank.

[0061] FIG. 7 is a cross-sectional view of still another shape example of a tank.

DESCRIPTION OF EMBODIMENTS

[0062] Hereinafter, an embodiment of the invention will be described with reference to the accompanying drawings.

[0063] As illustrated in FIGS. 1 and 2, a LNG tanker has a structure in which a bow area 10, a tank space 12, an engine room 14, and a stern area 16 are connected in this order from the front side, and an accommodation area 18 and a steering room 20 are provided above the engine room. The tank space 12 is divided into a plurality of sections by transfer bulkheads 22. Reference sign 23 denotes a bulkhead provided for the bow area 10.

[0064] The invention relates to a LNG ship in which each independent tank 30 having a substantially prismatic shape is installed inside a hold while not being integrated with hull (double hull) structure materials 32 and 33.

[0065] Further, the bottom surface of the independent prismatic tank 30 is provided with inclined surfaces 30A provided at the left and right sides of the center line direction of the ship as the boundary so that each angle θ intersecting a horizontal line H becomes equal to or smaller than 4.0°. Then, support bodies 34, 34 . . . integrated with the hull structure material 33 are arranged so as to correspond to the inclined surfaces 30A and 30A, and the tank 30 is put on the support bodies 34, 34 . . . .

[0066] Further, a center portion of the bottom surface of the tank 30 is provided with a flat surface 30B. Then, a receiving body 35 integrated with the hull structure material 33 is provided so as to correspond to the flat surface 30B, and the flat surface 30B is installed on the receiving body 35. The support bodies 34, 34 . . . are arranged along a ship longitudinal direction.

[0067] In the invention, since a structure is employed in which the tank 30 is provided as the independent prismatic tank and is installed inside the hold while not being integrated with the hull structures (for example, the double hull structures) 32 and 33 (without any welding structure), there is an economical advantage in that a high-cost material is not needed. Further, since the tank 30 has the substantially prismatic shape, the volumetric efficiency of the tank 30 is larger than that of the spherical tank.

[0068] The bottom surface of the prismatic tank 30 is provided with the inclined surfaces 30A formed at the left and right sides of the center line direction of the ship as the boundary so that each angle θ intersecting the horizontal line H becomes equal to or smaller than 4.0°, the support bodies 34, 34 . . . integrated with the hull structure material 33 are arranged so as to correspond to the inclined surfaces 30A and 30A, and the tank 30 is put on the support bodies 34, 34 . . . . Thus, there is possibility that sideslip of the tank 30 may occur with thermal deformation of the hull caused by a change in LNG amount inside the tank. This thermal deformation sideslip is suppressed or prevented by friction resistance between the bottom surface 30A of the tank 30 and the support bodies 34 having inclined top surfaces.

[0069] The inclination angle θ intersecting the horizontal line H of the bottom surface 30A of the tank 30 is not limited. However, when the inclination angle θ is set to be large, there is a possibility that the liquid cargo amount may decrease and an extreme sideslip may occur. Accordingly, it is desirable that the inclination angle θ be equal to or smaller than 4.0° and be 0.5° to 2.5°.

[0070] Meanwhile, it is desirable to employ a structure in which a key portion 40 is integrally formed with a center upper portion of the tank 30 in a protruding manner and anchor point chocks 41 and 41 are provided in the hull structure material so as to be located at the front and rear sides in the center line direction of the ship corresponding to the key portion 40. Thus, it is possible to restrict the thermal deformation sideslip of the tank for forward and back direction.

[0071] Although not illustrated in the drawings, a heat insulating material can be provided on the outer surface of the tank 30.

[0072] In the above-described example, the support bodies 34, 34 . . . are arranged along the ship longitudinal direction, but can be arranged appropriately. For example, as illustrated in FIG. 5, the support bodies can be arranged in a zigzag pattern.

[0073] The “substantially prismatic independent tank” of the invention may be a prismatic shape in the cross-section as a whole, and does not need to be a precise prismatic shape. For example, as illustrated in FIG. 6, it is possible that a tank 30C includes chamfered corners 30a and round corners 30b and inclined top surfaces 30c.

[0074] Further, as illustrated in FIG. 7, it is possible that a tank 30D includes a small tank 30d at an upper portion and a main tank 30e at a lower portion.

[0075] As a material of the tank 30, aluminum alloy, 9% nickel steel, stainless steel, or the like can be used.

[0076] The above-described embodiments can be used in combination.

INDUSTRIAL APPLICABILITY

[0077] The invention can be applied to a LNG carrier and in addition, the invention can be applied also to a FLNG (LNG-FPSO (Floating Production, Storage and Off-loading system)), FSRU, and SRV, which require handling of sloshing phenomenon in the same manner as the LNG carrier.

[0078] In the FLNG (LNG-FPSO), impurities of natural gas from a marine gas field are removed and the natural gas is liquefied to produce LNG so that the LNG is stored on a ship or a barge having a LNG storage capacity. Then, the LNG is shipped off to a LNG ship for carrying the LNG. As compared with a case where a liquefied natural gas plant is constructed on the land, this system has the following advantages: a pipeline from the marine gas field to the land can be reduced; an environmental load can be reduced because development on the coast is not required; and workers can be comparatively easily secured because the LNG-FPSO is constructed in a country or a region different from those in which a gas field is developed and is towed to the site.

[0079] The LNG ship of the present invention includes a re-gasification unit and the examples of the re-gasification unit are an FSRU (Floating Storage and Re-gasification Unit) and SRV (Shuttle and Re-gasification Vessel). The FSRU is mounted with a re-gasification unit and fixes a ship having an LNG storage capacity on the sea and receives LNG from the other LNG ship. The natural gas re-gasified by the FSRU is sent out to a pipeline on the land. The SRV does not transfer LNG from the other LNG ship but transports LNG loaded in at a liquefaction base to a demand area, re-gasifies the LNG on the deck, and sends out the re-gasified natural gas to a pipeline on the land.

REFERENCE SIGNS LIST

[0080] 10: bow area, 12: tank space, 14: engine room, 16: stern area, 18: accommodation area, 20: steering room, 30, 30A to 30D: independent prismatic tank, 30A: inclined surface, 30B: flat surface, 32, 33: hull structure material, 34: support body, 35: receiving body, θ: inclination angle