KR20100130666A - Offshore floating structure and its temporary buoyancy restoration method - Google Patents

Abstract

Here, a marine floating structure is disclosed which is mooring in the ocean by buoyancy and mooring lines fixed to the seabed. The disclosed marine floating structure includes a ballast tank and a temporary buoyancy generating device for restoring the buoyancy at a location where the buoyancy is lost when the buoyancy by the ballast tank is lost. In this case, the ballast tank is installed on each of a plurality of wings connected to the body of the marine floating structure, the temporary buoyancy generating device is provided on each of the wings. The temporary buoyancy generating device is preferably a gas bag that is filled with gas and expands when the ballast tank is submerged.

Description

FLOATING OFFSHORE STRUCTURE AND ITS TEMPORARY BUOANCY RECOVERY METHOD}

The present invention relates to an offshore floating structure, and more particularly, to a technique for temporarily restoring the buoyancy of an offshore floating structure when a part of it is lost buoyancy. The invention is particularly well suited for offshore floating structures for wind power generation.

In general, a marine floating structure can be moored while floating in the ocean, and in the moored state, various kinds of work such as power generation, fossil fuel extraction, production, refining, storage and / or unloading are performed. have. Marine floating structures are classified into various types according to their functions, structures, and mooring methods. For example, SEMI (Semi-submersible), TLP (Tensioned Leg Platform), SPAR, Floating, Production, Storage and Off-loading ), There are many types of offshore floating structures called FSRUs or drilling rigs.

Offshore floating structures use one type of mooring system, depending on their type. For example, FPOS type marine floating structures and SPAR type marine floating structures take a taut mooring or semi-taut mooring method, and TLP type marine floating structures are tensioned. Take a TLP mooring scheme using the legs).

The TLP mooring method is a method of mooring a buoyant offshore floating structure to the ocean, by applying a strong tensile force to vertical mooring lines called 'tandems'. Compared to semi-taut mooring, it is possible to keep the marine floating structure stable even in rough marine conditions. However, the TLP mooring method has a disadvantage in that there is a risk of breakage due to the large tension applied to the tandem. In particular, in mild marine conditions, the efficiency of the TLP mooring method is inevitably deteriorated in that it is not necessary to keep the marine floating structure firmly.

In recent years, there has been a significant increase in interest in offshore floating structures for wind power, for a number of reasons, including site costs, limited installation size, and difficulty in agreeing with nearby residents. And, it is disclosed in Korea Patent Publication No. 10-2009-0041616, Korean Patent Publication No. 10-2009-0028972 and the like with respect to the offshore floating structure for wind power generation or its mooring technology. The offshore floating structure for wind power generation has the advantage that it is possible to perform wind power generation in the ocean where the wind is not affected by the land topography, so that stable and steady power generation is possible. Where wind is not affected by land topography, wind power generation at sea far from land is more advantageous, as it is more suitable for wind power generation at sea.

However, wind power offshore floating structures have extremely limited dynamic movement under harsh marine conditions such as typhoons and bad weather due to the structural characteristics (or weaknesses) of wind power installations such as blades and / or nacelles. This causes a limited selection of mooring systems for offshore floating structures for wind power generation. Therefore, the TLP mooring method, which maintains the position of the floating structure with strong tensile force applied to the mooring line called 'tandem' or 'tensile angle', is applied to the marine structure for wind power generation as compared to the turret mooring or semi-turret mooring method. Will be more advantageous.

However, if some of the offshore structures, in particular, some of the offshore floating structures for wind power generation, are damaged by flooding or the like, some of the offshore structures may lose some buoyancy, which creates a large concentrated load on the mooring lines used in the TLP mooring scheme. This can lead to serious accidents such as cutting of mooring lines and, moreover, overturning of marine floating structures. Conventionally, when flooding occurs in a marine floating structure including a vessel, a pump is used to delay the flooding, or a plurality of barrier ribs are provided in advance in the ballast tank, so that the flooding of one area is transferred to the flooding of another area. It was just to suppress things.

Accordingly, one technical problem of the present invention is to provide a marine floating structure capable of temporarily restoring buoyancy in a part of a structure, in particular, when buoyancy is lost in a wing part with a ballast tank by flooding or the like. It is.

In addition, another technical problem of the present invention is to provide a method for temporarily restoring the buoyancy in a portion of the buoyancy when there is a loss of buoyancy in a portion of the marine floating structure by immersion.

Another technical problem of the present invention is to provide a marine floating structure, which is equipped with a device for temporarily restoring buoyancy, and which can cope particularly well with flooding of offshore floating structures for wind power generation.

According to one aspect of the present invention, by the buoyancy and mooring lines fixed to the seabed, there is disclosed a marine floating structure mooring floating in the ocean. The disclosed marine floating structure includes a ballast tank and a temporary buoyancy generating device for restoring the buoyancy at a location where the buoyancy is lost when the buoyancy by the ballast tank is lost.

Preferably, the ballast tank is installed on each of a plurality of wings connected to the body of the marine floating structure, the temporary buoyancy generating device is provided on each of the wings. More preferably, the temporary buoyancy generating device may be a gas bag that is filled with gas and expands when the ballast tank is submerged.

According to one embodiment, the mooring lines are connected to each of the plurality of wings, the wings can be installed foldable on the side of the body, in this case, the angle of the mooring lines in the marine environment and thus mooring lines You can change it according to their tension change.

According to another aspect of the present invention, in a marine floating structure mooring floating in the ocean by buoyancy and mooring lines fixed to the seabed, the buoyancy is lost when there is a buoyancy loss in a portion of the marine floating structure. Provided is a temporary buoyancy restoration method of a marine floating structure, characterized in that to temporarily restore the buoyancy of the portion using a gas bag.

According to the present invention, when a portion of the marine floating structure loses (or loses) buoyancy due to flooding, a temporary buoyancy generating device, in particular, a gas bag, is applied to a portion of the marine floating structure in which the buoyancy is lost and does not go down. It provides temporary buoyancy, allowing it to be restored to or near its original state. Thus, it is possible to prevent the risk of major accidents, such as the cutting of mooring lines and, moreover, the overturning of the marine floating structure, which may be caused by buoyancy loss of a portion of the marine floating structure. In addition, the use of a gas bag makes it possible not only to be efficient but also to significantly reduce costs, compared to delaying inundation in the conventional manner. It is also possible to simplify the plumbing facility.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. The following embodiments are provided as examples to ensure that the spirit of the present invention to those skilled in the art will fully convey. Accordingly, the invention is not limited to the embodiments described below and may be embodied in other forms. And, in the drawings, the width, length, thickness, etc. of the components may be exaggerated for convenience. Like numbers refer to like elements throughout.

1 is a view showing a marine floating structure according to an embodiment of the present invention, Figure 2 is a view showing a major part of the marine floating structure shown in FIG. The marine floating structure described below is a wind power offshore structure that best fits the present invention. Note, however, that the present invention does not exclude itself from being applied to other types of marine floating structures.

As shown in FIG. 1, the marine floating structure 1 according to an embodiment of the present invention includes a body 2 and a plurality of wings 4. Each of the vanes 4 is provided with a ballast tank 41 (see FIG. 2), either compartmentally or integrally, to provide buoyancy to the marine floating structure.

Although not shown, it may be contemplated to install a ballast tank on a part of the main body 2 as well. Although shown in the figure as two wings 4, the number of wings 4 may be three or more. In addition, the main body 2 is provided with a wind turbine, the wind turbine of the present embodiment, the blade 21 that rotates by the wind and the natsel 22 for generating electricity from the rotational force of the blade 21. Include.

The marine floating structure 1 remains moored at a position in the ocean by a plurality of mooring lines (or mooring lines, or tandems 8), floating by buoyancy. One end of each of the mooring lines 8 is fixed to the seabed, for which it is used a plurality of bases 9 fixedly arranged by heavy weight or anchoring on the seabed. The other end of each of the mooring lines 8 is connected to and fixed to each of the wings 4.

On the other hand, the marine floating structure (1) is a device for temporarily restoring the buoyancy of the damaged portion when the ballast tank 41, the flooding of the ballast tank 41, due to damage to its part, in particular, the wing 4, gas bag (10). The gas bag 10 is located at any part of the wing 4, folded or agglomerated, without being filled with gas, in a normal mooring state. On the contrary, when the ballast tank 41 is submerged and buoyancy loss occurs in the wing portion of the marine floating structure 1, the gas bag 10 is filled with air or any other gas, and the marine floating structure ( Restore the buoyancy at that part of 1).

The means for operating the gas bag 10 may be various, for example, using various types of pressure caused by flooding or using the explosive force of the explosive force due to excessive pressure or the impact, such as airbags of automobiles Means for detecting the phenomenon, and a pump that can blow gas into the gas bag 10 may be used. The phenomena caused by the immersion may be various, such as direct contact with the water at the sensing position, the pressure, the inclination angle at that position, and the sensor for detecting such phenomena may use a known.

2, the wing 4 is provided with a ballast tank 41 and a receiving portion 42 of the gas bag 10. In addition, the bag 42 may be housed in a folded or agglomerated state in which the gas (particularly, air) is not filled. Alternatively, the gas bag 10 may not be stored and may be fixed to the wing 4. When the ballast tank 41 is submerged, the gas bag 10 is filled with gas and expands, thereby generating buoyancy to lift the wing (4).

The vanes 4 may be fixed so as not to change position with respect to the main body 2, but according to an embodiment of the present invention, the vanes 4 may be varied in position with respect to the main body 2. Is installed. This is to enable the angle change of the mooring lines 8 as described in detail below.

Referring back to FIG. 1, the marine floating structure 1 may be moored according to changes in the marine environment, that is, whether the marine environment is a harsh condition such as a typhoon or bad weather, or a mild condition. It is possible to change the angle of the field. In addition, the marine floating structure (1) is provided with each of the wings (4), the length adjusting portion 6 to enable the adjustment of the tension received by the mooring line (8). The length adjusting section 6 can be used with various devices or mechanisms that can vary the effective length of the mooring lines 8, such as, for example, a winch.

3 (a) and (b) show the action of the marine floating structure to change the angle of the mooring line 8 according to the change of the marine environment and the tension of the mooring line (8).

As shown in (a) of FIG. 3, the marine floating structure wishes to mooring the mooring line 8 vertically or almost close to vertical when a large tension is applied to the mooring line 8 in a rough marine environment. Let's do it. In addition, as shown in Fig. 3B, when the tension applied to the mooring lines 8 is reduced in a mild marine environment, the mooring lines 8 are inclined apart. At this time, the mooring lines 8 maintain the marine floating structure in a relatively loose state. In order to vary the angle of the mooring lines 8, the vanes 4 should be variable in position with respect to the main body 2, for which each of the vanes 4 is foldable on the side of the main body 2. Is installed. At this time, the position of the mooring line 8 in the sea bottom is fixed.

As shown in FIG. 3 (b), when each of the vanes 4 is folded vertically to face the side of the main body 2, the mooring lines 8 are inclined outwardly. In this case, the length adjusting part 6 increases the length of the mooring line 8, and thus, the mooring lines 8 are loosely and inclined. At this time, because the mooring line 8 is loose, hardly any force is applied to the mooring line 8 and the mooring system including the mooring line, which causes its lifespan deterioration or damage. In addition, since the mooring lines 8 are inclinedly spread, the mooring structure 8 maintains the marine floating structure in the same manner as in the general turret mooring or semi-turtle mooring method. At this time, assuming that the mooring lines 8 are loose and vertical, the marine floating structure 1 may not be stably moored to the ocean.

As in FIG. 3 (a), when each of the vanes 4 is laid out horizontally, the mooring lines 8 are vertical or nearly close to vertical. At this time, the length adjuster 6 reduces the length of the mooring lines (8), and thus, the mooring lines (8) is in a tension state by applying a large tension. The vertical mooring lines 8 keep the marine floating structure firm and robust in the TLP (Tensioned Leg Platform) manner. In the state shown in FIG. 3A, the marine floating structure may be stably moored even in a harsh marine environment.

1 illustrates an offshore floating structure in accordance with one embodiment of the present invention.

FIG. 2 shows a major part of the marine floating structure shown in FIG. 1.

Figure 3 (a) and (b) is a view showing the action of the marine floating structure to change the angle of the mooring line according to the change of the marine environment and the tension of the mooring line.

Claims (5)

In a marine floating structure moored in the ocean by buoyancy and mooring lines fixed to the sea floor, Ballast tanks; And a temporary buoyancy generator for restoring the buoyancy at the location where the buoyancy is lost when the buoyancy by the ballast tank is lost. The marine floating structure of claim 1, wherein the ballast tank is installed on each of a plurality of wings connected to the main body of the marine floating structure, and the temporary buoyancy generating device is provided on each of the wings. The marine floating structure according to claim 2, wherein the temporary buoyancy generator is a gas bag that is filled with gas and expands when the ballast tank is flooded. The marine floating structure of claim 2, wherein the mooring lines are connected to each of the plurality of wings, and the wings are foldable on a side of the main body. In a marine floating structure mooring floating in the ocean by buoyancy and mooring lines fixed to the sea floor, when there is a buoyancy loss in a part of the marine floating structure, the buoyancy of the portion where the buoyancy is lost Temporary buoyancy restoration method of the marine floating structure, characterized in that the temporary restoration using.

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