EP2297405B1 - Structure for loading and unloading at least one ship for transporting fluids - Google Patents

Description

The present invention relates to a structure for loading and unloading at least one fluid transport vessel, such as, for example, hydrocarbons, liquefied natural gas (LNG), liquefied petroleum gas (LPG) or any other gas liquefied.

The present invention applies in particular to the transfer of this type of product between a ship and a fixed structure constituted, for example, by a liquefaction unit or a regasification terminal during the loading of the ship, or a fluid reservoir during its unloading.

Given certain safety constraints and vessel movements, it is preferable to carry out fluid transfer operations by keeping the vessel out of a port, in deeper waters, for example a few hundred meters from the shore. .

To carry out such operations on the high seas, there are in particular ship loading and unloading stations comprising a fluid transfer platform attached to the seabed by a fixing structure consisting of a set of sunken piles. in the seabed.

The platform supports articulated fluid transfer arms, intended to be connected to ship's transom systems called "manifolds" on the ship.

Known loading stations further include a set of dolphins (commonly referred to as "mooving dolphins") for absorbing the ship's docking energy and the tide after docking. The dolphins are also set on the seabed by rigid metal piles.

The fluid transfer platform is connected to a tank located on the coast or on a fixed platform at sea by a flexible pipe or a partially or totally immersed pipeline.

This type of transfer platform requires a very large number of piles and is of a high cost and the intervention of heavy equipment for installation.

Moreover, because of their remoteness from the coast, this type of transfer platform is subject to offshore swell and it is therefore necessary to orient them so that when the vessel is moored there, It is facing the dominant swell. In addition, the wind factor must be taken into account in the same way as the swell.

An object of the invention is to propose a structure for loading and unloading at least one ship that can be transportably transported from a manufacturing site to the loading or unloading site of the ship and also easily installed on this site. site, while resisting waves of very high heights in extreme conditions. The document BE 1 010 063 A describes a ship loading and unloading structure according to the preamble of claim 1.

The subject of the invention is therefore a structure for loading and unloading at least one transport vessel of a fluid formed by a docking dock of the ship comprising at least one concrete box provided with closure means and with opening for moving said at least one box by filling of water between a floating position for transporting the wharf and a position anchored in the seabed in which this wharf comprises a lower submerged anchor part and an upper part partially out of the water for docking said vessel, characterized in that the lower part of said at least one box comprises at least one compartment provided with closing and opening means, each formed by a bottom plate of the compartment connected to means moving said bottom plate between a closed position of the corresponding compartment and an open position of this compartment.

• le quai comporte plusieurs caissons placés bout à bout et reliés entre eux par des moyens d'emboîtement complémentaires,
• la partie inférieure dudit au moins caisson comporte plusieurs compartiments munis chacun des moyens de fermeture et d'ouverture,
• les moyens de déplacement sont formés par des moyens de déplacement pas à pas ou continu de la plaque de fond,
• ledit au moins un compartiment du caisson comporte au moins un organe de verrouillage de la plaque de fond en position de fermeture pour maintenir étanche ledit compartiment,
• le bord inférieur de la partie inférieure dudit au moins un caisson comporte des moyens d'enfoncement du caisson dans le fond marin, et
• les moyens d'enfoncement sont formés par des orifices de projection d'un fluide sous pression dans le fond marin.

According to other features of the invention:

• the platform comprises several boxes placed end to end and interconnected by complementary interlocking means,
• the lower part of said at least one box comprises a plurality of compartments each provided with means for closing and opening,
• the displacement means are formed by means of stepwise or continuous displacement of the bottom plate,
• said at least one compartment of the box comprises at least one locking member of the bottom plate in the closed position to maintain said compartment sealed,
• the lower edge of the lower part of said at least one box comprises means for driving the box into the seabed, and
• the driving means are formed by orifices for projecting a fluid under pressure into the seabed.

• la figure 1 est une vue schématique de dessus d'une structure de chargement et de déchargement selon l'invention, après l'accostage d'un navire de transport d'un fluide,
• la figure 2 est une vue schématique de dessus d'un caisson en béton de la structure de chargement et de déchargement selon l'invention,
• la figure 3 est une vue schématique en coupe verticale du caisson de la figure 2, en position de flottaison,
• la figure 4 est une vue schématique du caisson de la figure 2, en position ancrée dans le fond marin, et
• la figure 5 est une vue schématique en perspective partiellement arrachée des moyens d'ouverture et de fermeture d'un compartiment du caisson de la structure, selon l'invention.

The invention will be better understood on reading the description which follows, given solely by way of example, and with reference to the appended drawings, in which:

• the figure 1 is a diagrammatic view from above of a loading and unloading structure according to the invention, after the docking of a vessel carrying a fluid,
• the figure 2 is a schematic view from above of a concrete box of the loading and unloading structure according to the invention,
• the figure 3 is a schematic view in vertical section of the box of the figure 2 , in the flotation position,
• the figure 4 is a schematic view of the box of the figure 2 , in a position anchored in the seabed, and
• the figure 5 is a schematic perspective view partially broken away of the means for opening and closing a compartment of the box structure, according to the invention.

On the figure 1 schematically shows a structure designated by the general reference 20, loading and unloading at least one vessel 1 for transporting a fluid, such as for example liquefied hydrocarbons, including liquefied gas, such as natural gas liquefied petroleum gas (LNG), liquefied petroleum gas (LPG), or any other type of liquefied gas.

In a conventional manner, the ship 1 comprises a floating hull 2 delimiting a lateral mooring edge 3 and at least one liquefied fluid storage tank 2a. The ship 1 further comprises, along its mooring edge 3, mooring lines 4 fixed respectively to the front, to the rear and in the median part of the ship 1.

The tank 4 comprises a plurality of manifolds 5 which open transversely with respect to the shell 2. Each manifold 5 is provided at its outer end with a removable connection piece 6 for their connection with a conduit 10 for transferring fluids to a terminal , not shown, disposed for example on the coast, or at sea, away from the structure 20 and which comprises liquefied hydrocarbon storage tanks. The duct 10, represented in dotted lines on the figure 1 is, in this case, a cryogenic conduit immersed in the body of water.

Referring now more specifically to Figures 1 to 3 the loading and unloading structure of the ship 1 will be described.

This structure 20 comprises a platform 21 for receiving and mooring the ship 1. This pier 21 comprises at least one caisson 22 of concrete and, in the embodiment shown in FIG. figure 1 , several boxes 22 placed end to end.

For this purpose, and as shown in figure 2 the end walls of each caisson 22 comprise complementary interlocking means constituted, on one of the end walls, by projecting elements 23 and, on the other opposite end wall, by a part recessed 24 for receiving the projecting elements 23 of the box 22 adjacent when the boxes are placed one after the other.

Each concrete caisson 22 is displaceable by filling water between a floating position represented in FIG. figure 3 allowing its transport between a manufacturing site and an offshore installation site where each box 22 is in a position anchored in the seabed A, shown in FIG. figure 4 .

Each box 22 has a lower portion 22a allow the water filling of the box 22, as will be seen later, and an upper portion 22b forming ducts for the passage for example connecting ducts, not shown, with the ship 1 where for the passage of any other organ. Thus, the passage of the connecting ducts in the upper parts 22b of the boxes 22 can protect these ducts from the swell and a possible shock.

In the flotation position shown in figure 3 , the lower part 22a of the box 22 is watertight and is partially immersed and the upper part 22b is above the level of the water B and, in the position anchored in the seabed A, the lower part 22a of the box 22 is immersed and partially sunk in the seabed A and the upper part 22b is partially out of the water for the docking of the ship 1.

The lower part 22a of the box 22 comprises at least one compartment 25 and, in the assembly shown in the figures, this lower part 22a has four compartments.

Each compartment 25 is provided with means 30 for closing and opening to move the box 22 by filling water between its floating position and its position anchored in the seabed A.

The means 30 for closing and opening each compartment 25 is constituted by a bottom plate 31 movable and connected to means 35 for moving this bottom plate 31 between a position sealingly closing the corresponding compartment 25 and a position opening the compartment 25. In the closed position of the compartment 25, the bottom plate 31 is supported on a flange 26a formed on the lower edge 26 of the lower part 22 of the box 21, as shown in FIG. figure 3 .

Referring now to Figures 3 to 5 a displacement means of a bottom plate 31 will be described, each displacement means being identical and a bottom plate 31 which can be associated with several displacement means 35.

Each moving means 35 is formed by a rod 36 having a lower end 36a connected to the corresponding bottom plate 31 by a hinge pin 37 and an upper end 36b free. The rod 36 passes through the lower portion 22a and the upper portion 22b of the box 22. The rod 36 carrying the bottom plate 31 is movable by means of stepwise or continuous.

In the case of means of displacement step by step, these means are constituted by two sets 38, a first set 38 being placed above the lower part 22a and a second set 38 being placed above the upper part 22b of the box 22.

Referring now to the figure 5 we will describe a set 38, the other sets being identical.

As schematically shown in figure 5 each set 38 comprises a plurality of jaws 39 movable transversely and perpendicularly to the corresponding rod 36 between a position spaced from this rod 36 and a position pressed against said rod 36. Each assembly 38 also comprises cylinders 40 for moving the jaws 39 vertically.

In the case of continuous displacement means of the rod 36 carrying a corresponding bottom plate 31, the displacement means are constituted, for example, by a rack and pinion assembly of known type, and not shown.

The displacement of each rod 36 may be effected by any other suitable system.

As shown more particularly on the figure 3 , each bottom plate 31 is associated with at least one locking member 41 of the bottom plate 31 in the sealed position of the corresponding compartment 25. Each locking member is constituted, for example, by a screw-nut mechanism of known type or by any other suitable mechanism.

To facilitate the anchoring of the box 22 in the seabed A in addition to the own weight of the box, the lower edge 26 of the lower part of this box 22 comprises means for driving the box 22 into the seabed A.

These driving means, represented at figure 5 are constituted by orifices 45 for projecting a fluid under pressure into the seabed A. These orifices 45 are distributed along the length of the lower edge 26 of the box 22.

One of the lateral faces of the upper portion 22b comprises a frame 50 formed of a trellis of beams on which is moored the ship 1 by means of the mooring lines 4, as shown in FIG. figure 1 .

On the lateral face opposite to that carrying the frame 50, the upper part 22b of the box 22 comprises breakwaters 51.

The installation at sea of the caissons 22 intended to form the platform 21 is carried out in the following manner.

Each box 22 is floated to the installation site. For this, the bottom plate 31 of each compartment 25 is maintained applied to the rim 26a of the lower edge 26 so as to seal each compartment 25 of the box 22. The bottom plate 31 of each compartment 25 is held in this position by at least one locking member 41, as shown in FIG. figure 3 .

On the ship mooring site, two methods for anchoring the caissons 22 to form the dock 21 are possible.

First, the boxes 22 are oriented such that the breakwaters 51 disposed on one side of the upper portion 22b of the box 22 are oriented on the side of the dominant swell to break the swell and protect the ship 1 when docked at Pier 21.

The first method of immersion caissons 22 is to immerse each box 22 separately.

The locking member 41 of each bottom plate 31 is retracted in order to release this bottom plate 31.

Then, the bottom plate 31 of each compartment 25 is moved from its closed position of the corresponding compartment 25 to its open position of this compartment 25. For this, the jaws 39 of the lower movement assembly 38 are locked in order to to lock the rod 36 carrying the bottom plate 31 to open. The jaws 39 of the upper displacement assembly 38 are unlocked on the corresponding rod 36 and the jacks 40 of the upper displacement assembly 38 are actuated, which has the effect of vertically moving the rod 36 upwardly and lifting. the bottom plate 31 of the corresponding compartment 25.

The water begins to enter the compartment 25 and after this first movement of the rod 36 and the bottom plate 31. The jaws 39 of the upper displacement assembly 38 are locked on the rod 36. The jaws 39 of the lower movement assembly 38 are unlocked and returned to their initial position by the cylinders 40.

Then, the cylinders 40 of the upper displacement assembly 38 are actuated to move the rod 36 and the bottom plate 31 by a new pitch. A greater quantity of water thus enters the compartment 25 of the lower part 22a of the box 22. The displacement of the rod 36 and the corresponding bottom plate 31 thus takes place in successive steps.

The bottom plates 31 of the compartments 25 of the box 22 can be moved synchronously or separately so that the box 22 gradually sinks and comes to rest on the seabed B. The boxes 22 intended to to form the entire platform 21 are thus immersed one after the other and placed on the seabed B.

The approximation and the nesting of the boxes one after the other can be performed by a system of cables and winches of known type, not shown. For this, a cable passes longitudinally through each caisson 22 via a longitudinal passage 47 ( figure 5 ) between the lower and upper portions 22a and 22b respectively of the box 22.

A second method of immersion caissons 22 to form the dock 21 is to assemble these caissons 22 one after the other floating.

The immersion of all the boxes 22 thus assembled is carried out, as above, by successively or simultaneously lifting the bottom plates 31 of all the compartments 25 of the boxes 22.

When laying the box 22 on the seabed A, this box 22 sinks gradually into the seabed A under the effect of its own weight and this depression is facilitated by the projection of a fluid under pressure in the bottom 45. The bottom plates 31 of the compartments 25 are held in the open position of each compartment 25, as shown in FIG. figure 4 .

When the caissons 22 constituting the pier 21 are thus anchored in the seabed A with the breakwaters 51 directed towards the dominant swell, the conduits, not shown, provided in the upper part 22b of the caissons 22 of the pier 21 and intended to unload a ship 1 after docking, are connected to the subsea conduit 10 so as to transfer the fluid discharged from the ship 1 to the coast and to a storage site.

The number of boxes 22 makes it possible to control and control the descent of the wharf when it is laid on the seabed. Indeed, the greater the number of boxes 22 is important, the more it is possible to open and / or close boxes to stabilize the descent of the entire dock.

According to a variant, the lower part 22a of the boxes 22 may represent a cylindrical section and, in this case, the bottom plate 31 of each compartment 25 is curvilinear.

The loading and unloading structure according to the invention has the advantage of being able to be brought to the site of loading or unloading by flotation and also to allow the docking of a ship under difficult conditions.

The structure according to the invention can be easily anchored at sea without requiring the driving of a multitude of piles and the intervention of heavy equipment for its installation. A simple tug is enough to bring the dock to the docking site.

Claims (8)

1. Structure (20) for loading and unloading at least one fluid transport ship (1), the structure (20) being formed by a quay (21) for mooring the ship (1), said quay comprising at least one concrete caisson (22) equipped with closing and opening means for moving said caisson, by filling it with water, between a floating position for transporting the quay (21) and a position anchored in the seabed, in which this quay (21) comprises a submerged lower part (22a) for anchoring purposes and an upper part (22b), partially out of the water, for the berthing of said ship (1) characterised in that the lower part (22a) of said at least one caisson (22) comprises at least one compartment (25) equipped with closing and opening means (30), each being formed by a bottom plate (31) of the compartment (25) connected to means (35) for displacing said bottom plate (31) between a position of closing the corresponding compartment (25) and a position of opening this compartment (25).
2. Structure (20) according to claim 1, characterised in that the quay (21) comprises a plurality of caissons (22) placed end to end and connected to one another by complementary joining means (23, 24).
3. Structure (20) according to claim 1 or 2, characterised in that the lower part (22a) of said at least one caisson (22) comprises a plurality of compartments (25), each equipped with closing and opening means (30).
4. Structure (20) according to claim 3, characterised in that the displacement means (35) are formed by means (38, 39, 40) for the step-by-step displacement of the bottom plate (31), or by means for continuous displacement.
5. Structure (20) according to any one of the preceding claims, characterised in that said at least one compartment (25) of the caisson (22) comprises at least one member (41) for locking the bottom plate (31) in the closed position so as to keep said compartment sealed.
6. Structure (20) according to any one of the preceding claims, characterised in that the lower edge (26) of the lower part (22b) of said at least one caisson (22) comprises means (45) for embedding the caisson (22) in the seabed.
7. Structure (20) according to claim 6, characterised in that the embedding means are formed by orifices (45) for spraying a pressurised fluid into the seabed.
8. Structure (20) according to any one of the preceding claims, characterised in that the upper part (22a) of the quay (21) comprises breakwaters (51) on the side opposite that on which the ship (1) berths.

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