A vessel comprising a superstructure and a liquefied gas storage tank provided at the rear of the superstructure.

Abstract

The invention relates to a ship (1) with a superstructure and a sealed, insulated tank (2) arranged aft of the superstructure in the longitudinal direction (X'-X). The tank has a bottom wall (22), two longitudinal walls (24) and two chamfered bottom walls (25) connecting the bottom wall (22) and the longitudinal walls, respectively. One of the chamfered bottom walls borders the bottom wall at its bottom edge (32) and the adjacent longitudinal wall at its intermediate edge (33). The distance (B) between the center line (31) and the intermediate edge of the bottom wall parallel to the transverse direction (Z'-Z) and the distance (C1) between the bottom edge and the intermediate edge parallel to the transverse direction (Z'-Z) satisfy the inequality C1 ≥ 0.45B. It is particularly applicable to ships for transporting bulk solid products.

Description

[Technical field]

[0001] The present invention relates to the field of ships comprising a superstructure and a sealed, insulated tank for the cryogenic storage of liquefied combustible gas, placed aft of said superstructure, the tank containing the liquefied combustible gas that serves as fuel for propulsion of the ship.

[0002] In one embodiment, the liquefied combustible gas is liquefied natural gas (LNG), a methane-rich mixture stored at atmospheric pressure and a temperature of about −162° C. Other liquefied combustible gases are possible, such as ethane, propane, butane, liquefied petroleum gas (LPG), ethylene, ammonia, or methanol, among others. [Background technology]

[0003] Ships have already been proposed in CN 110789663, KR 10-2015-0082929 or CN 108502102, in which a sealed, insulated tank for storing LNG is arranged at the rear of the ship's superstructure, allowing the ship to be propelled mainly or even entirely with LNG instead of diesel oil as usually used in the maritime sector, which offers certain advantages, in particular by limiting certain environmentally polluting wastes and by achieving this without locating the tanks in places that have traditionally been used to transport the ship's cargo and payload.

[0004] However, the movement of the ship at sea, influenced by weather conditions such as sea or wind conditions, causes agitation of the liquid in the tanks. Such agitation, commonly referred to as "sloshing", causes distortions in the tank walls which can compromise the tank's integrity. Tank integrity is particularly important in LNG tanks due to the flammable or explosive nature of the liquids transported and the risk of cold spots developing in the ship's steel hull.

[0005] Furthermore, in the ships proposed in the above mentioned publications, the risk of tank damage due to sloshing is increased by the presence of two different factors:

[0006] Firstly, the LNG contained in the tanks is gradually consumed during the ship's voyage, so that the tanks are neither completely full nor completely empty for the majority of the voyage. It is also known that a tank that is neither completely full nor completely empty increases the risk of damage due to sloshing, because when the tank is empty, the weight of the liquid remaining in the tank is limited, which causes only weak deformations in the tank walls, whereas when the tank is full, the remaining space not occupied by liquid is limited, which proportionally limits the freedom of movement of the liquid in the tank and therefore limits the impact forces on the tank walls.

[0007] The second factor is that the above-mentioned location of the tanks aft of the superstructure 6 located at the aft of the vessel results in the tanks being located very far from the metacentre of the vessel, which exacerbates the movement of liquid contained in the tanks and in turn exacerbates the risk of damage to the tanks due to sloshing caused by this movement of liquid. Summary of the Invention

[0008] The starting point for certain aspects of the present invention is the consideration that, where it is desirable to locate a tank aft of the superstructure, it is important to ensure that such a location of the tank does not increase the risk of damage to the tank due to sloshing.

[0009] One idea on which the invention is based is therefore to propose a ship of the above type in which the tanks are able to withstand damage caused by sloshing even if they are placed aft of the superstructure.

[0010] Therefore, the ship proposed by the present invention has: a hull extending in a longitudinal direction of the vessel, the hull comprising a bottom and an upper deck spaced apart from the bottom in a vertical direction of the vessel; - a superstructure located in the last aft quarter of the vessel in the longitudinal direction and extending above the upper deck in the vertical direction; a sealed, insulated tank for the storage of liquefied combustible gas, arranged aft of the superstructure in the longitudinal direction; It is equipped with The tank has a tank wall including a bottom wall, a ceiling wall spaced apart from the bottom wall, two longitudinal walls, two chamfered upper walls respectively connecting the ceiling wall and the longitudinal walls, and two chamfered bottom walls respectively connecting the bottom wall and the longitudinal walls, the two longitudinal walls being parallel to each other and spaced apart in the transverse direction of the vessel; the lateral direction is perpendicular to the longitudinal direction and the vertical direction of the vessel; The bottom wall has a centerline extending parallel to a longitudinal axis of the vessel; one of the chamfered bottom walls contacts the bottom wall at a bottom edge and contacts the adjacent longitudinal wall at an intermediate edge; A distance B parallel to the lateral direction between the center line of the bottom wall and the intermediate edge, and a distance C1 parallel to the lateral direction between the bottom edge and the intermediate edge satisfy an inequality C1≧0.45B.

[0011] The references "last aft quarter" and "aft of the superstructure" are to be taken in relation to the normal longitudinal forward motion of the ship, respectively. The references "forward of" are to be taken in relation to the normal longitudinal forward motion of the ship, respectively.

[0012] The applicant has discovered that the above tank sizing tends to reduce the risk of damage to the tank due to sloshing, so that the tank can withstand damage due to sloshing even when located aft of the superstructure.

[0013] In some embodiments, a vessel as described above may include one or more of the following features:

[0014] In one embodiment, the distance B and the distance C1 satisfy the inequality 0.50B ≧ C1 ≧ 0.45 B. Such dimension setting tends to facilitate installation of a scaffold inside the tank during construction of the tank.

[0015] In another embodiment, the distance B and the distance C1 satisfy the inequality C1≧0.60B. The applicant has found that the tank dimensioning described above significantly reduces the risk of damage to the tank due to sloshing, so that the tank is more able to withstand damage due to sloshing even when located aft of the superstructure.

[0016] Furthermore, the large chamfered bottom wall of the tank compared to the bottom wall allows a relatively large free space within the hull below the chamfered bottom wall in which other equipment of the vessel can be accommodated.

[0017] In one embodiment, the two chamfered bottom walls are symmetrical with respect to a plane of symmetry that is parallel to the vertical direction and includes centerlines of the bottom walls.

[0018] In one embodiment, the tank is symmetrical about a plane of symmetry that is parallel to the vertical direction and includes a centre line of the bottom wall.

[0019] In one embodiment, the plane of symmetry coincides with a mid-plane of the hull extending parallel to the longitudinal axis of the vessel.

[0020] With such an arrangement, the tank is not only symmetrical about the plane of symmetry but is also centred with respect to the ship's hull, which tends to reduce sloshing.

[0021] In one embodiment, the surface area of ​​the top wall of the tank is greater than the surface area of ​​the bottom wall of the tank.

[0022] In one embodiment, the chamfered bottom wall meets the bottom wall at the bottom edge such that the bottom wall forms an angle equal to 45° with the chamfered bottom wall.

[0023] This configuration allows the tank walls, or at least the bottom and chamfered bottom walls, to be manufactured in the manner known for membrane tanks, which allows their manufacture at an angle of 45°. Moreover, an angle equal to 45° allows a large free space in the hull below the chamfered bottom wall. However, other values ​​of said angle are also possible.

[0024] In one embodiment, one of the chamfered top walls meets the top wall at a top edge and meets the adjacent longitudinal wall at a second intermediate edge such that the chamfered top wall forms an angle equal to 45° with the top wall.

[0025] In one embodiment, a distance H parallel to the vertical direction of the vessel between the bottom edge and the top edge, and a distance C3 parallel to the vertical direction of the vessel between the second intermediate edge and the top edge satisfy the inequality C3≧0.17H.

[0026] In one embodiment, the distance C1 is strictly greater than the distance C3, while in another embodiment, the distance C1 is equal to the distance C3.

[0027] In one embodiment, the tank wall further comprises two lateral walls parallel to each other and spaced apart in the longitudinal direction of the vessel.

[0028] In one embodiment, each tank wall has a multi-layer structure comprising, from the exterior to the interior of the tank, a secondary insulating barrier, a secondary sealing membrane arranged in contact with the secondary insulating barrier, a primary insulating barrier arranged in contact with the secondary sealing membrane, and a primary sealing membrane arranged in contact with the primary insulating barrier, the primary sealing membrane being in contact with the liquefied gas.

[0029] In one embodiment, the vessel further comprises a plurality of intermediate decks located between the bottom of the hull and the upper deck, the intermediate decks including a first intermediate deck, and the tank extending in the vertical direction from the first intermediate deck above the upper deck.

[0030] Such an arrangement allows the tank's fill volume to be varied by simply changing the height of the portion of the tank that extends above the upper deck, without significantly altering the rest of the ship's configuration, thereby allowing the ship's liquefied combustible gas capacity to be tailored to suit the ship's requirements.

[0031] In one embodiment, the intermediate deck further includes a second intermediate deck located above the first intermediate deck in the vertical direction, and the intermediate edge is located between the second intermediate deck and the upper deck in the vertical direction.

[0032] In one embodiment, the vessel further comprises a plurality of cofferdam walls surrounding the tanks, each tank wall being secured to an opposing cofferdam wall.

[0033] The cofferdam wall constitutes a structural assembly which is fixed to the ship's hull and which completely encloses the tank, ensures sufficient structural fixation of the tank to the hull, protects the tank from the external elements despite the fact that part of the tank is located above the upper deck, and prevents any contact between the hull and liquefied combustible gas in the event of an accidental leakage from the tank.

[0034] In one embodiment, the cofferdam walls include two longitudinal cofferdam walls and two chamfer cofferdam walls, each of the two longitudinal walls of the tank being fixed to a respective one of the longitudinal cofferdam walls and each of the two chamfer bottom walls of the tank being fixed to a respective one of the chamfer cofferdam walls, one of the chamfer cofferdam walls contacting the longitudinal cofferdam wall at a mid-cofferdam edge, the mid-edge being above the mid-cofferdam edge in the vertical direction of the ship.

[0035] In one embodiment, the cofferdam wall further comprises two lateral cofferdam walls, each of the two lateral walls of the tank being secured to a respective lateral cofferdam wall.

[0036] In one embodiment, the tank includes a pump for venting liquefied flammable gas from the interior volume of the tank.

[0037] In one embodiment, the bottom wall includes a sump and the pump includes a pump head disposed in the sump.

[0038] With this configuration, the volume of liquefied flammable gas that cannot be pumped by the pump can be significantly reduced.

[0039] In one embodiment, the vessel further comprises a gas vent mast having a mast body and a mast head, a first end of the mast body being fixed to the vessel aft of the superstructure in the longitudinal direction of the vessel and above the ceiling wall of the tank in the vertical direction of the vessel, the mast head being arranged at a second end of the mast body and having an opening for venting the combustible gas that has entered the tank, and the mast body being inclined so that the second end is farther away from the superstructure than the first end in the longitudinal direction of the vessel.

[0040] Such an arrangement ensures that the openings allowing the venting of flammable gas contained in the tanks are located as far away as possible from the superstructure, which contributes to protecting the ship's personnel in the event of serious tank damage and / or overpressurization.

[0041] In one embodiment, the vessel further comprises at least one liquefied combustible gas suction device for transporting liquefied combustible gas to the tank, the liquefied combustible gas suction device being arranged on the upper deck, forward of the superstructure in the longitudinal direction of the vessel, preferably in a lateral area of ​​the upper deck in the transverse direction of the vessel.

[0042] In one embodiment, a tank connection space having a dome structure is provided on the upper part of the ceiling wall of the tank, and a liquefied flammable gas charging duct is passed through this space and penetrates the ceiling wall of the tank.

[0043] In one embodiment, the vessel further comprises a propulsion system, and the tank supplies the combustible gas to the propulsion system.

[0044] Such an arrangement would enable the vessel to be propelled primarily by burning liquefied combustible gas contained in the tanks, thereby reducing certain environmentally polluting waste products associated with the burning of marine diesel, and would accomplish this without locating the tanks in locations traditionally used to transport the vessel's cargo or payload.

[0045] In one embodiment, the vessel further comprises at least one gas management system arranged above the ceiling wall of the tank, the gas management system configured to supply liquefied combustible gas contained in the tank to the propulsion system.

[0046] In one embodiment, the propulsion system comprises a main engine and at least one auxiliary engine, the main engine being located within the hull, forward of the tank in the longitudinal direction of the vessel, and the auxiliary engines being located within the hull, outboard of the main engine in the transverse direction of the vessel.

[0047] In one embodiment, the main engine is arranged in a main engine room provided on the first intermediate deck and the second intermediate deck within the extent of the symmetrical plane of the tank, and the auxiliary engine is arranged in an auxiliary engine room provided on the second intermediate deck, outside the main engine room in the transverse direction of the ship.

[0048] In one embodiment, the propulsion system comprises a combustible gas vent duct connected to both the main engines and the auxiliary engines, the combustible gas vent duct passing through the second intermediate deck between the tank and the superstructure in the longitudinal direction of the vessel.

[0049] This reduces the overall length of piping required to vent the combustion gases from the auxiliary and main engines.

[0050] In one embodiment, the combustion gas vent duct merges into a funnel located longitudinally of the vessel between the tank and the superstructure.

[0051] In one embodiment, the liquefied combustible gas is liquefied natural gas. In one embodiment, the liquefied combustible gas is a liquefied combustible gas selected from the group consisting of ethane, propane, butane, liquefied petroleum gas (LPG), ethylene, ammonia, and methanol, in particular selected from the group consisting of ethane, propane, butane, liquefied petroleum gas (LPG), and ethylene.

[0052] In one embodiment the vessel comprises at least one hold for transporting bulk solid products, forward of the superstructure in the longitudinal direction of the vessel.

[0053] In one embodiment, the vessel has a loading opening through the upper deck and is configured to allow loading of bulk solid products into the hold via the loading opening.

[0054] In one embodiment, the vessel comprises a plurality of holds longitudinally of the vessel forward of the superstructure, the holds being spaced apart longitudinally of the vessel, the holds including the hold closest to the superstructure.

[0055] In one embodiment, the liquefied combustible gas suction device is arranged on the upper deck, forward of the superstructure in the longitudinal direction of the ship and aft of the loading opening of the hold closest to the superstructure.

[0056] With this configuration, the liquefied combustible gas suction device is positioned relatively close to the superstructure and relatively close to the rear of all hold loading openings, thereby reducing the length of the pipeline transporting the liquefied combustible gas to the tank and also reducing the risk of the load on the liquefied combustible gas suction device dropping.

[0057] In one embodiment, the present invention provides a liquefied flammable gas transfer system comprising a vessel as described above, an insulated pipeline arranged to connect the tank of the vessel to a floating or onshore storage facility, and a pump for driving a flow of liquefied flammable gas from the floating or onshore storage facility to the tank of the vessel or from the tank of the vessel to the floating or onshore storage facility via the insulated pipeline.

[0058] In one embodiment, the present invention provides a method for loading a vessel as described above, comprising transporting liquefied combustible gas from a floating or onshore storage facility to the tanks of the vessel via an insulated pipeline.

[0059] The present invention will be better understood and other objects, details, features and advantages of the present invention will become more apparent from the following description of several specific embodiments of the present invention, taken in conjunction with the accompanying drawings, in which the specific embodiments are merely illustrative and are not intended to limit the present invention. [Brief description of the drawings]

[0060] [Figure 1] FIG. 2 is a cross-sectional view of the aft part of a ship in which a sealed insulated tank for storing liquefied combustible gas is provided, the tank being arranged aft of the ship's superstructure in the longitudinal direction of the ship. [Diagram 2] FIG. 2 is a cross-sectional view of the vessel taken along line II-II in FIG. 1 . [Diagram 3] FIG. 3 is a cross-sectional view of the vessel taken along line III-III in FIG. 1 . [Figure 4] FIG. 2 is a schematic cross-sectional view of half of the tank of the ship of FIG. 1, illustrating important quantities of tank dimensioning. [Diagram 5] FIG. 2 is a cross-sectional view of the vessel taken along plane V in FIG. [Figure 6] FIG. 2 is a cross-sectional view of the vessel taken along plane VI of FIG. 1. [Figure 7] A cross-sectional view of the vessel along plane VII of Figure 1. [Figure 8] FIG. 1 is a schematic diagram showing a ship equipped with a sealed insulated tank for storing liquefied combustible gas and a terminal for loading said tank, the tank being located aft of the ship's superstructure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0061] Hereinafter, a ship 1 equipped with a sealed, insulated tank for storing liquefied flammable gas will be described with reference to Figures 1 to 8. This tank is disposed at the rear of the ship 1's superstructure.

[0062] FIG. 1 shows a cross-sectional view of the aft part of a ship 1. The ship 1 is in this figure a bulk carrier, which is a ship designed for the transport of bulk solid products. The ship 1 therefore comprises, as is self-evident, one or more holds 9 for transporting bulk solid products, forward of the superstructure 6 in the longitudinal direction X'-X of the ship 1. The above-mentioned holds 9 are, as is self-evident, spaced apart from one another in the longitudinal direction X'-X of the ship 1. It should be noted that only one of the holds 9 is shown diagrammatically in FIG. 1, i.e. only the hold 9 closest to the superstructure 6. As is self-evident, each hold 9 is accessible from a loading opening 99 passing through the upper deck 5, through which bulk solid products can be introduced into each hold 9.

[0063] However, what is described below is also applicable to types of ships other than bulk carriers, provided that the ship has a superstructure 6.

[0064] As just mentioned, the ship 1 is equipped with a superstructure 6 of self-evident construction, which is located in the last aft quarter of the ship 1 in the longitudinal direction X'-X of the ship 1. The terms "last aft quarter" and "aft of the superstructure 6" are each based on the normal forward direction F of the ship 1 in the longitudinal direction X'-X. The term "forward of" is also based on the above-mentioned forward direction F of the ship 1.

[0065] As is self-evident, the hull 3 of the vessel 1 comprises a bottom 4 and an upper deck 5 spaced apart from the bottom 4 in the vertical direction Y'-Y of the vessel 1, the bottom 4 being possibly double-walled, and a superstructure 6 extending above the upper deck 5 in the vertical direction Y'-Y. As is self-evident, the superstructure 6 is a structure covering various decks 6D for the crew of the vessel 1, and also comprises a bridge 6P at the top that houses various devices for the crew of the vessel 1 to operate the vessel 1.

[0066] The vessel 1 comprises a sealed, insulated tank 2, which will hereinafter be referred to for convenience as "tank 2". The tank 2 is adapted to store a liquefied flammable gas. In one embodiment, the liquefied flammable gas is liquefied natural gas (LNG). Other liquefied flammable gases are also possible, such as ethane, propane, butane, liquefied petroleum gas (LPG), ethylene, ammonia or methanol, among others. The liquefied flammable gas contained in the tank 2 is supplied to a propulsion system 80, which will be described in more detail below.

[0067] The structure of the tank 2 and the arrangement of the tank 2 in the ship 1 will be described in detail below.

[0068] Generally, as shown in Figures 1, 6 and 7, the tank 2 is arranged aft of the superstructure 6 in the longitudinal direction X'-X.

[0069] 1, the ship 1 further includes a first intermediate deck 11, a second intermediate deck 12, and a third intermediate deck 13. These intermediate decks 11, 12, and 13 extend between the bottom 4 and the upper deck 5, and are spaced apart from each other in the vertical direction Y'-Y.

[0070] 1, 2 and 3, the tank 2 extends from the second intermediate deck 12 to above the upper deck 5 in the vertical direction Y'-Y.

[0071] Figure 2 is a cross-sectional view of the ship 1 along the plane II-II in Figure 1, and Figure 3 is a cross-sectional view of the ship 1 along the plane III-III in Figure 1. Both figures are therefore cross-sectional views of the tank 2 in the transverse direction Z'-Z of the ship 1. It should be noted that the transverse direction Z'-Z is perpendicular to the longitudinal direction X'-X and the vertical direction Y'-Y.

[0072] 2 and 3, the tank 2 has tank walls including a bottom wall 22, a top wall 23, two longitudinal walls 24, two chamfered bottom walls 25, and two chamfered top walls 26. The tank walls, together with two lateral walls (not shown) extending parallel to the lateral direction Z'-Z, define an internal volume 21 of the tank 2 for containing liquefied flammable gas.

[0073] Each tank wall has a multi-layer structure comprising, from the outside to the inside of the tank, a secondary insulating barrier, a secondary sealing membrane arranged against the secondary insulating barrier, a primary insulating barrier arranged against the secondary sealing membrane, and a primary sealing membrane arranged against the primary insulating barrier, the primary sealing membrane being in contact with the liquefied combustible gas. Such membrane tanks are described in particular by way of example in WO 2019 / 239048, WO 2014 / 057221, FR 2 691 520 and FR 2 877 638. The membrane tanks may in particular be according to the products GTT® Next1, Mark V®, Mark III® and NO96® developed by the Applicant.

[0074] As can be seen in Figure 3, a "tank connection space" (TCS) 50 is provided above the ceiling wall 23 of the tank 2. The tank connection space 50 has in particular a dome structure 29 through which a charging duct (not shown) passes and penetrates the ceiling wall 23, thereby filling the tank 2 with liquefied flammable gas. The tank connection space 50 is a secure space for connecting the duct penetrating the ceiling wall 23 to other devices of the ship 1.

[0075] 3 also shows that one or more "Fuel Gas Handling Systems" (FGHS) 51 are arranged above the ceiling wall 23 of the tank 2. The FGHS 51 are obviously arranged to supply liquefied combustible gas contained in the tank 2 to the propulsion system 80 by means of a set of ducts and valves which are not shown in the drawings.

[0076] With continued reference to FIG. 3, a "gas vent mast" 60 is provided at the top of the tank connection space 50, which will be described in more detail below.

[0077] As is self-evident, the internal volume 21 of the tank 2 is provided with at least one pump, not shown in the drawings, configured to deliver liquefied combustible gas from the internal volume 21 of the tank through the dome structure 29 to the propulsion system 80. The pump is supported, for example, by a self-evident tripod mast arranged in the internal volume 21 of the tank.

[0078] In one embodiment, the bottom wall 22 of the tank 2 is provided with a sump 65, and the pump is provided with a pump head contained in the sump 65. Such an arrangement is advantageous as it significantly reduces the volume of liquefied flammable gas that cannot be pumped by the pump. As a variant, as shown in Figure 3, the tank 2 can be provided with multiple pumps, and the bottom wall 22 can be provided with multiple separate sumps 65, each of which is adapted to receive a pump head of a corresponding pump.

[0079] The tank walls are surrounded by a set of cofferdam walls, generally designated 40, which can be seen more particularly in Figures 2 and 3. Each tank wall is secured to an opposing cofferdam wall of the set of cofferdam walls 40.

[0080] More specifically, the set of cofferdam walls 40 comprises the following: a bottom cofferdam wall 42 to which the bottom wall 22 of the tank 2 is fixed, - the upper cofferdam wall 43 to which the ceiling wall 23 of the tank 2 is fixed, - two longitudinal cofferdam walls 44. Each longitudinal wall 24 of the tank 2 is fixed to a respective longitudinal cofferdam wall 44; - Two chamfered cofferdam walls 45. Each chamfered bottom wall 25 of the tank 2 is fixed to a chamfered cofferdam wall 45, - two lateral cofferdam walls (not shown) extending parallel to the lateral direction Z'-Z. Each of the two lateral walls (not shown) of the tank 2 is fixed to a respective lateral cofferdam wall.

[0081] As shown in FIGS. 2 and 3, each chamfer cofferdam wall 45 abuts an adjacent longitudinal cofferdam wall 44 at an intermediate cofferdam edge 49 .

[0082] It can be well understood that the set of cofferdam walls 40 constitute a structural assembly fixed to the hull 3 of the ship 1 and encloses the entirety of the tanks 2, ensuring sufficient structural fixation of the tanks 2 to the hull 3, protecting the tanks 2 from the external elements despite portions of the tanks 2 being located above the upper deck 5, and preventing any contact between the hull 3 and liquefied flammable gas in the event of an accidental leakage from the tanks 2.

[0083] By arranging the tank 2 aft in the longitudinal direction X'-X of the superstructure 6 arranged at the aft part of the ship 1 as described above, the tank 2 is arranged at a position very far from the metacenter (not shown) of the ship 1. This aggravates the movement of the liquefied flammable gas in the tank 2, and thus aggravates the risk of damage to the tank 2 caused by sloshing due to the movement of the liquefied flammable gas. In the following, with particular reference to FIG. 4, a configuration of the tank 2 that can withstand damage caused by sloshing even if the tank 2 is arranged aft of the superstructure in the longitudinal direction X'-X will be described.

[0084] A centre line 31 of the bottom wall 22 can be defined, extending parallel to the longitudinal direction X'-X of the vessel 1. The term "central" means that the centre line 31 divides the bottom wall 22 in half to obtain two half-walls of equal surface area. In the example shown, the centre line 31 corresponds to the central axis in the height direction of the tank 2. A plane 31P perpendicular to the bottom wall 22 and containing the centre line 31 thus divides the internal volume 21 of the tank 2 into two equal volumetric parts.

[0085] The heightwise central axis of the tank 2 may optionally pass through a dome structure 29 as shown in FIGS.

[0086] 2, 3 and 4, the chamfered bottom wall 25 meets the bottom wall 22 at a bottom edge 32 such that the bottom wall 22 forms an angle δ (see FIG. 4) with the bottom wall 22 equal to 45°. Additionally, the chamfered bottom wall 25 meets the adjacent longitudinal wall 24 at an intermediate edge 33.

[0087] Referring to Figures 2 and 3, the intermediate edge 33 can be located between the intermediate deck 13 and the upper deck 5 in the vertical direction Y'-Y, and / or the intermediate edge 33 can be located above the intermediate cofferdam edge 49 in the vertical direction Y'-Y.

[0088] Referring to FIG. 4, the following definitions apply: the distance B parallel to the transverse direction Z'-Z between the centre line 31 and the intermediate edge 33, the distance C1 parallel to the transverse direction Z'-Z between the bottom edge 32 and the middle edge 33, a distance C2 parallel to the vertical direction Y'-Y between the bottom edge 32 and the middle edge 33.

[0089] Distances C1, C2 and B are all understood to be relative dimensions of the chamfered bottom wall 25 and the bottom wall 22 of the tank 2. It is also seen that C1=C2 since the chamfered bottom wall 25 meets the bottom wall 22 at the bottom edge 32 at an angle δ between them equal to 45°.

[0090] Furthermore, the distances C1 and B are set to satisfy the inequality C1≧0.60B.

[0091] When the dimensions of the tank 2 are set as just described, the chamfer bottom wall 25 will be relatively larger than the bottom wall 22 and will be inclined at 45° to the bottom wall 22. The Applicant has observed that such a configuration very significantly reduces the risk of damage to the tank 2 due to sloshing, in particular by reducing the risk of the liquefied flammable gas entering the tank 2 rushing into the chamfer top wall 26, and more generally by allowing the chamfer bottom wall 25 to absorb more of the impact of the liquefied flammable gas.

[0092] As a variant, the distances C1 and B are set to satisfy the inequality C1≧0.45B, for example 0.5B≧C1≧0.45B. Such dimensioning tends to reduce the risk of damage to the tank 2 due to sloshing, albeit to a lesser extent than if C1≧0.60B. Furthermore, the above-mentioned dimensioning tends to ensure that the surface area of ​​the bottom wall 22 is sufficient for providing scaffolding within the tank 2 during construction of the tank 2, which tends to facilitate providing such scaffolding.

[0093] As shown in the drawings, the tank 2, or at least the chamfered bottom wall 25, may be symmetrical about a plane 31P.

[0094] It should be noted that the plane 31P may coincide with a mid-plane (unsigned) of the hull 3 extending parallel to the longitudinal direction X'-X of the ship 1. Thus, the tank 2 is not only symmetrical with respect to the plane 31P, but also centered with respect to the hull 3 of the ship 1, which configuration tends to reduce sloshing.

[0095] It should also be noted that the angle δ formed by the chamfered bottom wall 25 and the bottom wall 22 at the bottom edge 32 can be other than 45°. For example, the value of this angle δ can be on the order of about 135°, or any other value feasible for a membrane tank.

[0096] 2, 3 and 4, the chamfered upper wall 26 is in contact with the ceiling wall 23 at an upper edge 35 thereof at an angle ζ (see FIG. 4) equal to 45° with the ceiling wall 23. Furthermore, the chamfered upper wall 26 is in contact with the adjacent longitudinal wall 24 at an intermediate edge 34 thereof.

[0097] Referring again to Figure 4, the following definitions are given: the distance H parallel to the vertical direction Y′-Y between the bottom edge 32 and the top edge 35, the distance C3 parallel to the vertical direction Y′-Y between the middle edge 34 and the upper edge 35, a distance C4 parallel to the transverse direction Z'-Z between the middle edge 34 and the upper edge 35.

[0098] The distances C3, C4 and H are all understood to be relative dimensions of the chamfered upper wall 26 and the ceiling wall 23 of the tank 2. It is also understood that C3=C4 since the chamfered upper wall 26 is in contact with the ceiling wall 23 at the upper edge 35 so as to form an angle ζ between the upper wall 26 and the ceiling wall 23 equal to 45°.

[0099] Furthermore, the distances C3 and H are set to satisfy the inequality C1 ≧ 0.17H.

[0100] Furthermore, in some embodiments, the distance C1 is strictly greater than the distance C3 and / or the surface area of ​​the top wall 23 of the tank 2 is greater than the surface area of ​​the bottom wall 22 of said tank 2.

[0101] In other embodiments, the distance C1 may be equal to the distance C3, such that C1=C2=C3=C4.

[0102] The arrangement of the tank 2 described above with reference to the drawings is merely one example, and various other arrangements of the tank 2 are possible as long as the tank 2 is arranged rearward of the superstructure 6 in the longitudinal direction X'-X.

[0103] As already mentioned, a "gas vent mast" 60 is provided at the top of the tank connection space 50. For example, as described in WO 2019 / 097131, the mast 60 has a mast body 60C and a mast head (not shown) arranged at one end 62 of the mast body 60C, and the mast head is provided with an opening 63 capable of venting the combustible gas contained in the tank 2, and this configuration is self-evident.

[0104] As will also be apparent, the gas vent mast 60 is provided to enable venting of flammable gas contained in the tank 2 in the event of serious damage and / or overpressure occurring to the tank 2, and is provided to avoid serious destruction and / or explosion of the tank 2 by venting the flammable gas in the tank 2 in this manner.

[0105] An end portion 61 of the mast body 60C opposite to the one end 62 is fixed to the ship 1 above the ceiling wall 23 of the tank 2 and at the rear of the superstructure 6. For example, as shown in Figures 1 and 3, the end portion 61 is fixed above the tank connection space 50.

[0106] 1, the mast body 60C is inclined in the longitudinal direction X'-X such that the one end 62 is farther away from the superstructure 6 than the end 61. This configuration ensures that the opening 63, through which the combustible gas contained in the tank 2 can be vented, is located as far away as possible from the superstructure, thereby ensuring that the opening 63 is located as far away as possible from the deck 6D and the bridge 6P. This contributes to protecting the crew of the ship 1 in the event of serious damage and / or overpressure of the tank 2. It can also be seen that, in the event of serious damage and / or overpressure of the tank 2 while the ship 1 is moving forward in the forward direction F, the relative wind caused by the inertia of the ship 1 tends to push the combustible gas further back from the superstructure 6, which further contributes to protecting the crew.

[0107] As already mentioned, the liquefied combustible gas contained in the tank 2 is supplied to the propulsion system 80. The propulsion system 80 and the arrangement of the propulsion system 80 on the vessel 1 will now be described more specifically with reference to Figures 1 and 5.

[0108] The propulsion system 80 comprises a main engine 81 which drives the propeller 7 via a corresponding drive shaft 7A (see FIG. 1). The main engine 81 may be of any known type capable of consuming liquefied combustible gas from the tank 2. In some variations not shown, more than one main engine 81 may be provided.

[0109] The propulsion system 80 further comprises three auxiliary engines 82 (see FIG. 5), for example turbo-electric propulsion motors for the vessel 1 and / or generators used to power the various electrical components of the vessel 1. The auxiliary engines 82 can be of any known type, provided they are capable of consuming liquefied combustible gas from the tanks 2. As a variant, a different number of auxiliary engines 82 can be provided.

[0110] 5, the main engine 81 is disposed in the hull 3, forward of the tank 2 in the longitudinal direction X'-X. For example, the central axis of the main engine 81 can be aligned with the above-mentioned plane 31P of the tank 2. Furthermore, the auxiliary engine 82 is disposed in the hull 3, outboard of the main engine 81 in the transverse direction Z'-Z. For example, the main engine 81 is disposed in a main engine room 121 provided on the intermediate decks 11 and 12, within the expanse of the plane 31P of the tank 2, whereas the auxiliary engine 82 is disposed in an auxiliary engine room 122 provided on the intermediate deck 12, outboard of the main engine room 121 in the transverse direction Z'-Z.

[0111] The arrangement of the main engine 81 and the auxiliary engine 82 just described allows venting of combustion gases from the main engine 81 and the auxiliary engine 82 through one combustion gas vent duct 88 (see FIG. 1), thereby reducing the overall length of piping required for venting the combustion gases. With reference to FIG. 1, the duct 88 penetrates the intermediate deck 13 between the tank 2 and the superstructure 6 in the longitudinal direction X'-X. With reference to FIGS. 1, 5 and 6, the duct 88 merges into the funnel 8 arranged between the tank 2 and the superstructure 6 in the longitudinal direction X'-X.

[0112] Referring again to FIG. 5, a tank 89 for holding "marine diesel oil" can be provided on the outer side of the main engine room 121 and opposite the auxiliary engine room 122 in the lateral direction Z'-Z.

[0113] 1 and 7, the ship 1 is provided with at least one self-evident liquefied flammable gas intake device (also referred to as a "bunker station") 90 in order to take in liquefied flammable gas into the tanks 2. In the illustrated example, two devices 90 are provided in total, one on each side of the ship 1 in the transverse direction Z'-Z, more specifically, one on each side area of ​​the upper deck 5 in the transverse direction Z'-Z.

[0114] The device 90 is disposed on the upper deck 5, forward of the superstructure 6 in the longitudinal direction X'-X. More specifically, in the illustrated example, the device 90 is disposed on the upper deck 5, forward of the superstructure 6 in the longitudinal direction X'-X and aft of the opening 99 closest to the superstructure 6. With this configuration, the length of the pipeline 99C that transports the liquefied flammable gas to the tank 2 is reduced, and the risk of the load on the device 90 dropping is reduced.

[0115] Referring to Figure 8, a vessel 1 of the type described above is shown equipped with a sealed insulated tank 2 mounted within the hull 3 of the vessel 1, aft of the superstructure 6 of the vessel 1. As will be appreciated, a vessel loading pipeline can be coupled to an offshore or port terminal using suitable connectors to transfer a cargo of LNG to the tank 2.

[0116] FIG. 8 shows an example of a marine terminal with a loading station 75, a subsea duct 76 and a shore facility 77. The loading station 75 is a fixed offshore facility consisting of a movable arm 74 and a tower 78 supporting the movable arm 74. The movable arm 74 supports a bundle of insulated flexible pipes 79 that can be connected to the loading pipeline of a ship. The movable arm 74 is directional adjustable and is suitable for all ship types. A connecting duct (not shown) runs inside the tower 78. The loading station 75 allows loading of LNG fuel from the shore facility 77 to the ship 1 or unloading of LNG fuel from the ship 1 to the shore facility 77. The shore facility 77 comprises a liquefied gas storage tank 80 and a connecting duct 81 that is connected to the loading station 75 by a subsea duct 76. The subsea duct 76 is capable of transferring liquefied gas over long distances, for example 5 km, between the loading station 75 and the onshore facility 77, thereby enabling the vessel 1 to be kept at a great distance from shore during loading operations.

[0117] To generate the pressure required for the transfer of the liquefied gas, pumps on board the ship 1 and / or pumps provided at the shore facility 77 and / or pumps provided at the loading station 75 are used.

[0118] Although the present invention has been described with reference to several specific embodiments, it is clear that the present invention is in no way limited to these specific embodiments, and that all technical equivalents of the above-mentioned means and technically equivalent combinations of the above-mentioned means are included in the present invention, provided that they fall within the scope of the present invention.

[0119] Use of the verb "include" or "comprise" and its conjugated forms does not exclude the presence of elements or steps other than those stated in a claim.

[0120] In the claims, any reference signs in parentheses shall not be construed as limiting the scope of the claims.

Claims

1. A vessel (1), a hull (3) extending in the longitudinal direction (X'-X) of the vessel (1), the hull (3) comprising a bottom (4) and an upper deck (5) spaced apart from the bottom (4) in the vertical direction (Y'-Y) of the vessel (1); a superstructure (6) located in the rearmost quarter of the vessel (1) in the longitudinal direction (X'-X) and extending above the upper deck (5) in the vertical direction (Y'-Y); a sealed, insulated tank (2) for storing liquefied flammable gas, arranged aft of the superstructure (6) in the longitudinal direction (X'-X); It is equipped with The sealed insulated tank (2) has tank walls including a bottom wall (22), a ceiling wall (23) spaced apart from the bottom wall (22), two longitudinal walls (24), two chamfered upper walls (26) respectively connecting the ceiling wall (23) and the longitudinal wall (24), and two chamfered bottom walls (25) respectively connecting the bottom wall (22) and the longitudinal wall (24), the two longitudinal walls (24) are parallel to each other and spaced apart from each other in the transverse direction (Z'-Z) of the vessel (1); The transverse direction (Z'-Z) is perpendicular to the longitudinal direction (X'-X) and the vertical direction (Y'-Y) of the vessel (1), The bottom wall (22) has a center line (31) extending parallel to the longitudinal direction (X'-X) of the vessel (1); One of the chamfered bottom walls (25) contacts the bottom wall (22) at a bottom edge (32) and contacts the adjacent longitudinal wall (24) at an intermediate edge (33); A distance B parallel to the lateral direction (Z'-Z) between the center line (31) of the bottom wall (22) and the intermediate edge (33) and a distance C1 parallel to the lateral direction (Z'-Z) between the bottom edge (32) and the intermediate edge (33) satisfy the inequality C1≧0.45B. A vessel (1) characterized in that:

2. The distance B and the distance C1 satisfy the inequality C1≧0.60B. A vessel (1) according to claim 1.

3. The sealed insulated tank (2) is symmetrical with respect to a plane of symmetry (31P) that is parallel to the vertical direction (Y'-Y) and includes a center line (31) of the bottom wall (22). A vessel (1) according to claim 1 or 2.

4. Each of the tank walls has a multi-layer structure, The multilayer structure includes, from the exterior to the interior of the sealed, insulated tank, a secondary insulating barrier, a secondary sealing membrane arranged in contact with the secondary insulating barrier, a primary insulating barrier arranged in contact with the secondary sealing membrane, and a primary sealing membrane arranged in contact with the primary insulating barrier, the primary sealing membrane being in contact with the liquefied gas; the chamfered bottom wall (25) meets the bottom wall (22) at the bottom edge (32) at an angle (δ) equal to 45° with the bottom wall; A vessel (1) according to claim 1 or 2.

5. The ship further comprises a plurality of intermediate decks located between the bottom (4) of the hull (3) and the upper deck (5), The intermediate deck includes a first intermediate deck (12), The sealed insulated tank (2) extends in the vertical direction (Y'-Y) from the first intermediate deck (12) toward above the upper deck (5). A vessel (1) according to claim 1 or 2.

6. The intermediate deck further includes a second intermediate deck (13) located above the first intermediate deck (12) in the vertical direction (Y'-Y), The intermediate edge portion (33) is located between the second intermediate deck (13) and the upper deck (5) in the vertical direction. A vessel (1) according to claim 5.

7. The tank further comprises a plurality of cofferdam walls (40) surrounding the sealed insulated tank (2); Each of the tank walls is fixed to the opposing cofferdam wall. A vessel (1) according to claim 1 or 2.

8. The cofferdam walls include two longitudinal cofferdam walls (44) and two chamfer cofferdam walls (45); Each of the two longitudinal walls (24) of the sealed, insulated tank (2) is fixed to the longitudinal cofferdam wall (44), The two chamfered bottom walls (25) of the sealed insulated tank (2) are fixed to the chamfered cofferdam wall (45), respectively; One of the chamfered cofferdam walls (45) abuts the longitudinal cofferdam wall (44) at an intermediate cofferdam edge (49); the intermediate edge (33) is above the intermediate cofferdam edge (49) in the vertical direction (Y'-Y) of the ship (1); A vessel (1) according to claim 7.

9. The bottom wall (22) is provided with a sump (65); The sealed insulated tank (2) is provided with a pump for venting liquefied flammable gas from an internal volume (21) of the sealed insulated tank (2), The pump comprises a pump head that is contained in the sump (65). A vessel (1) according to claim 1 or 2.

10. The invention further comprises a gas vent mast (60) having a mast body (60C) and a mast head, a first end (61) of the mast body (60C) is fixed to the ship (1) at the rear of the superstructure (6) in the longitudinal direction (X'-X) of the ship (1) and above the ceiling wall (23) of the sealed insulated tank in the vertical direction (Y'-Y) of the ship (1); the mast head is disposed at the second end (62) of the mast body (60C) and has an opening (63) for venting the flammable gas contained in the sealed insulated tank (2); The mast body (60C) is inclined so that the second end (62) is farther away from the superstructure (6) than the first end (61) in the longitudinal direction (X'-X) of the ship (1). A vessel (1) according to claim 1 or 2.

11. The system further comprises at least one liquefied flammable gas intake device (90) for conveying liquefied flammable gas to the sealed insulated tank (2); the liquefied flammable gas suction device (90) is arranged on the upper deck (5) forward of the superstructure (6) in the longitudinal direction (X'-X) of the ship (1), and is preferably arranged in a lateral region of the upper deck (5) in the transverse direction (Z'-Z) of the ship (1); A vessel (1) according to claim 1 or 2.

12. further comprising a propulsion system (80); The sealed insulated tank (2) supplies the propulsion system (80) with combustible gas. A vessel (1) according to claim 1 or 2.

13. The propulsion system (80) comprises a main engine (81) and at least one auxiliary engine (82); The main engine (81) is disposed in the hull (3) forward of the sealed insulated tank (2) in the longitudinal direction (X'-X) of the ship (1), The auxiliary engine (82) is disposed in the hull (3) outside the main engine (81) in the transverse direction (Z'-Z) of the ship (1). A vessel (1) according to claim 12.

14. The vessel further comprises a plurality of intermediate decks located between the bottom (4) of the hull (3) and the upper deck (5), The intermediate deck includes a first intermediate deck (12), The sealed insulated tank (2) extends in the vertical direction (Y'-Y) from the first intermediate deck (12) above the upper deck (5), The intermediate deck further includes a second intermediate deck (13) located above the first intermediate deck (12) in the vertical direction (Y'-Y), The intermediate edge portion (33) is located between the second intermediate deck (13) and the upper deck (5) in the vertical direction, the propulsion system (80) comprises a combustion gas vent duct (88) connected to both the main engine (81) and the auxiliary engine (82); the combustion gas vent duct (88) passes through the second intermediate deck (13) between the sealed insulated tank (2) and the superstructure (6) in the longitudinal direction (X'-X) of the ship (1); A vessel (1) according to claim 13.

15. the combustion gas vent duct (88) joins a chimney (8) arranged between the sealed insulated tank (2) and the superstructure (6) in the longitudinal direction (X'-X) of the ship (1); A vessel (1) according to claim 14.

16. The liquefied combustible gas is liquefied natural gas. A vessel (1) according to claim 1 or 2.

17. at least one hold (9) for transporting bulk solid products is provided forward of the superstructure (6) in the longitudinal direction (X'-X) of the vessel (1); A vessel (1) according to claim 1 or 2.

18. A liquefied flammable gas transfer system comprising: A vessel (1) according to claim 1 or 2; an insulated pipeline (73, 79, 76, 81) arranged to connect the sealed insulated tank (2) of the vessel (1) to a floating or coastal storage facility (77); a pump for driving the flow of liquefied flammable gas from the floating or onshore storage facility to the sealed insulated tank (2) of the vessel (1) or from the sealed insulated tank (2) of the vessel (1) to the floating or onshore storage facility via the insulated pipeline; A transfer system comprising:

19. 3. A method for loading a vessel (1) according to claim 1 or 2, comprising the steps of: The liquefied flammable gas is transported from a floating or offshore storage facility (77) to the sealed insulated tank (2) of the vessel (1) or from the sealed insulated tank (2) of the vessel (1) to the floating or offshore storage facility (77) via an insulated pipeline (73, 79, 76, 81). A method characterized by:

Images