CN111301622A - A movable offshore wind power floating foundation and its operation method - Google Patents

Abstract

The invention discloses a movable offshore wind power floating foundation and an operation method thereof. The foundation includes an offshore wind power floating foundation, a floating platform and a mooring system. The floating platform connects a column of a small water plane and a large water The combined design of the floating box on the line surface ensures the stability of the foundation; the anchor foundation utilizes the ballast weight and the frictional resistance provided by the skirt plate to provide pull-out resistance, the center can be filled with sand ballast, and the structure with the skirt plate at the bottom makes it possible to tow It can reach the operating waters, and can penetrate into the seabed through stacking and internal and external pressure difference, which is convenient for construction; the anchoring foundation can float to the sea surface through its own buoyancy, which is convenient for the migration of the floating foundation of offshore wind power, and can reuse the wind turbine in many places. The interior of the anchored foundation is divided into a plurality of sub-chambers by sub-chambers. During the installation, operation and dismantling process, the center of gravity and buoyancy position of the offshore wind power floating foundation can be adjusted through the sub-chambers, and the structural attitude is controlled, which is convenient for construction and operation.

Description

A movable offshore wind power floating foundation and its operation method

technical field

The invention belongs to the field of offshore wind power foundation, and in particular relates to a movable offshore wind power floating foundation and an operation method thereof.

Background technique

With the continuous consumption of oil, the energy crisis has become increasingly prominent. As a renewable and clean energy, offshore wind energy has become a new direction to alleviate the global energy tension. Offshore wind turbines installed in shallow water usually use fixed foundations. In deep sea areas, considering that the strength of various environmental loads such as waves, ocean currents, sea wind, and internal waves is greatly enhanced compared to offshore, the construction of traditional fixed foundations And installation costs will become very expensive, so floating foundations become a practical and effective solution to deep water problems.

At present, offshore wind power floating foundations mainly include three types: semi-submersible, Spar and TLP floating foundations. The main body of the semi-submersible floating foundation is composed of multiple columns and buoys, and the positioning is completed by the mooring system. The larger spacing between the columns results in a larger restoring moment, which is conducive to improving the structural stability. However, the buoys of the semi-submersible floating foundation under the waterline are larger in scale and will be subjected to larger wave loads, resulting in an increase in the amplitude of their surge motion. The main body of the Spar-type floating foundation is a bottom ballasted steel cylinder, which is connected to the seabed pile foundation through a radial mooring system. Due to the ballast weight at the bottom of the structure, its center of gravity is below the center of buoyancy, and the stability is better. However, the small waterline area of the Spar-type floating foundation makes the amplitude of pitch and roll motion larger, which may have a certain impact on the power generation performance of the upper wind turbine. The main body of the TLP type floating foundation is composed of a tower column and a buoy, and is connected to the seabed pile foundation through the tension tendon at the bottom. Tension tendons are tightened to increase the draft, and the buoyancy is greater than the structural gravity. The residual buoyancy is offset by the tension on the tension tendons, which makes the structure stable and the structural movement amplitude is small. Compared with other floating foundations, limited platform motion is expected to reduce structural loads on towers and blades, especially for sites where catenary mooring systems are not suitable, TLP floating wind turbines have better application prospects . However, the existing TLP wind turbine foundation generally adopts the type of pile foundation and suction foundation. Once it is in place, it is not easy to move again, the construction is difficult, and the migration cost is quite high.

SUMMARY OF THE INVENTION

The purpose of the present invention is to overcome the deficiencies of the prior art, and to provide a movable offshore wind power floating foundation.

The present invention is achieved through the following technical solutions:

A portable floating foundation for offshore wind power, including a floating platform and a mooring system;

The floating platform includes a column and a number of floating boxes; the floating boxes are radially and symmetrically arranged around the lower part of the column; The interior of the pontoon is divided into several sub-chambers, and each sub-chamber is provided with a valve for water vapor replacement;

the mooring system includes an anchor foundation and several sets of mooring lines;

The anchoring foundation is provided with four vertically arranged dividing plates, the interior of the dividing plates encloses a central stacking groove, a compartment is formed between the dividing plate and the outer wall of the anchoring foundation, and a second dividing plate is arranged in the compartment. The second sub-deck divides the cabin into a plurality of sub-chambers, and each sub-chamber is provided with a valve for water-vapor replacement; the bottom of the anchoring foundation is provided with an inner skirt plate and an outer skirt plate.

Each group of the mooring lines corresponds to a pontoon, the upper end of which is connected with the bottom of the pontoon, and the lower end is connected with the upper surface of the anchoring foundation;

In the above technical solution, the upper end of the column is connected to the fan tower through a flange.

In the above technical solution, the column is a cylindrical structure with a cavity, the diameter is 6-10m, the height is 15-25m, and the wall thickness is 50-100mm.

In the above technical solution, the number of the floating boxes is 4, which are arranged in a cross shape, and the upright column is located at the center of the cross shape.

In the above technical solution, the length of the floating box is 8-12m, the width is 3-7m, the height is 5-9m, and the wall thickness is 10-20mm.

In the above technical solution, the first sub-division board is arranged along the vertical direction, and divides the pontoon into an inner cabin and an outer cabin.

In the above technical solution, the cross section of the mat foundation is square, and the side length is 20-30m.

In the above technical solution, the cross section of the central stacking tank is a square with a side length of 8-12m and a height of 4-6m.

In the above technical solution, the height of the inner skirt plate and the outer skirt plate is 4-6m.

An operation method of a removable offshore wind power floating foundation, which is carried out according to the following steps:

(1) First, the floating platform and the mooring system are prefabricated on land respectively, the fan tower is installed stably on the floating platform, and the floating platform with the fan tower installed is towed Transport to the working sea area, and at the same time tow the mooring system to the working sea area, set up a buoy ball on the upper end of the mooring line, so that the upper end of the mooring line floats on the water surface;

(2) Water is injected into the subdivision of the anchoring foundation through the water-vapor replacement valve, so that the anchoring foundation loses buoyancy and sinks, and the anchoring foundation is embedded in the seabed and fixed by means of center stacking and internal and external pressure difference;

(3) Anchor the upper end of the mooring line to the floating box according to the position indicated by the buoy ball, and pre-tension the mooring line by 10% to 50% to balance the buoyancy of the floating platform, so that the the mooring line is under tension;

(4) Water is injected into the sub-chamber inside the floating tank through the water-vapor replacement valve, so that the floating platform with the fan tower installed loses part of its buoyancy and sinks. When it sinks to the design draft position, the mooring line is completed. The remaining 50% to 90% of the pretension is to balance the buoyancy of the floating platform;

(5) Adjust the center of gravity and the position of the center of buoyancy of the floating foundation for offshore wind power by injecting or pumping water into the subdivision of the floating box;

(6) When the offshore wind power floating foundation is migrated, water is injected into the sub-chamber inside the floating tank through the water-vapor replacement valve, so that the floating platform with the fan tower installed loses part of its buoyancy and sinks, and the the mooring line tension to separate the pontoon from the mooring line;

(7) Remove the central stack of the anchoring foundation, and gradually discharge the water body in the sub-chamber of the anchoring foundation through the water vapor replacement valve, so that the anchoring foundation floats to the sea surface by buoyancy;

(8) Tow and transport the floating platform and the mooring system with the fan tower installed to the target sea area, and install and operate again.

The advantages and beneficial effects of the present invention are:

1. The offshore wind power floating foundation of the present invention, its floating platform is designed by combining the small water plane column and the large water plane floating box to ensure that the foundation is provided enough floating stability by the large water plane floating box during towing. At the same time, when the fan is in position, the floating box is submerged underwater, and the column on the water surface of the small line is less affected by the wave load, which ensures the stability of the foundation.

2. In the offshore wind power floating foundation of the present invention, the anchoring foundation of the mooring system utilizes the ballast weight and the frictional resistance provided by the skirt plate to provide pull-out resistance, positioning the mooring line, and the anchoring foundation is the center that can be filled with sand ballast and the lower part. The structure with skirt plate and the larger water plane can be towed to the working water area, and can penetrate into the seabed through the stacking load and internal and external pressure difference, which is convenient for construction.

3. The offshore wind power floating foundation of the present invention has a hollow structure as the anchoring foundation of the mooring system, which can float to the sea surface through its own buoyancy, which is convenient for the migration of the offshore wind power floating foundation, and the wind turbine can be reused in many places. The interior of the anchored foundation is divided into a plurality of sub-chambers by sub-chambers. In the process of installation, operation and dismantling, the center of gravity and buoyancy position of the offshore wind power floating foundation can be adjusted through the sub-chambers, and the structural attitude is controlled, which is convenient for construction and operation.

Description of drawings

Fig. 1 is a three-dimensional schematic diagram of a movable offshore wind power floating foundation in the present invention;

Fig. 2 is the front view of a kind of movable offshore wind power floating foundation in the present invention;

FIG. 3 is a top view of a movable offshore wind power floating foundation of the present invention.

FIG. 4 is a schematic perspective view of the floating platform of the present invention.

FIG. 5 is a schematic diagram of the bottom structure of the anchoring foundation in the present invention.

FIG. 6 is a schematic diagram of the internal perspective structure of the anchor foundation in the present invention.

Among them: 1 is the column, 2 is the floating box, 3 is the mooring line, 4 is the anchoring foundation, 5 is the first subdivision plate, 6 is the second subdivision plate, 7 is the inner skirt plate, 8 is the outer skirt plate, 9 is the dividing plate, and 10 is the central stacking tank.

For those of ordinary skill in the art, other related drawings can be obtained from the above drawings without any creative effort.

Detailed ways

In order to make those skilled in the art better understand the solutions of the present invention, the technical solutions of the present invention are further described below with reference to specific embodiments.

Example

As shown in FIG. 1 to FIG. 5 , this embodiment discloses a movable offshore wind power floating foundation, which is composed of a floating platform and a mooring system.

The floating platform includes a column 1 and a floating box 2. The upper end of the column 1 is connected to the fan tower through a flange, and the lower part of the column 1 is fixedly connected to the floating box 2. Considering the large weight of the nacelle and blades of the offshore wind turbine and the 80-100m above the water surface, in order to make the wind turbine generate electricity normally, the stability of the foundation under the combined action of wind and waves and the ability to resist wind and wave loads must be ensured. The column 1 and the floating box 2 are made of steel structure, concrete structure or other light-weight materials, which can carry larger wind power loads. The design of the combination of the small water plane column 1 and the large water plane floating box 2, the large water plane floating box 2 provides sufficient buoyancy stability to realize the floating platform-tower-fan integral floating tow, easy installation and transportation ; In the in-position state, the floating box 2 dives below the water surface, and the column 1 on the small waterline plane is located on the water surface to reduce the influence of wave loads.

The column 1 is a cylindrical structure with a cavity, its diameter is 8m, the height is 20m, and the wall thickness is 50mm.

The floating box 2 is four radially symmetrically distributed cubic structures with cavities, the length of which is 10m, the width is 5m, the height is 7m, and the wall thickness is 15mm. Each box body of the floating box 2 is provided with a first subdivision board 5, and the first subdivision board 5 divides the inside of each box body of the floating box 2 into two inner and outer subdivisions, and each subdivision is equipped with two subdivisions. There is a valve for water and gas replacement, and the floating tank 2 can adjust the position of the center of gravity by adding water ballast in each sub-compartment to ensure the stability of the foundation towing. A mooring line connecting structure is provided at the bottom of the pontoon 2 near the outer edge for anchoring the mooring line 3 .

The mooring system includes an anchor foundation 4 and a mooring line 3 .

There are four vertically arranged dividing plates 9 inside the anchoring foundation. The interior of the dividing plates encloses a central stacking tank 10. A compartment is formed between the dividing plate and the outer wall of the anchoring foundation, and a second dividing plate is arranged in the compartment. The cabin plate 6 and the second sub-division plate divide the cabin into a plurality of sub-chambers, and each sub-chamber is provided with a valve that can replace water and gas; the anchoring foundation 4 can adjust the position of the center of gravity by adding water ballast in each sub-chamber. Ensure basic towing stability. The side length of the anchoring foundation is 25m, the side length of the central stacking tank is 10m, and the height is 5m; the inner and outer edges of the lower part of the anchoring foundation are provided with an inner skirt 7 and an outer skirt 8 with a height of 5m;

An anchor point is installed on the upper surface of the anchoring foundation for connecting with the lower end of the mooring line 3. Water ballast can be added to the sub-chamber, sand ballast can be filled in the center stacking tank, and the inner skirt plate 7 and the outer skirt plate 8 pass the pressure The load and the internal and external pressure difference penetrate into the seabed. After the anchoring foundation 4 penetrates into the seabed through the stacking load and internal and external pressure difference, the ballast load and the frictional resistance provided by the inner apron 7 and the outer apron 8 are used to provide pull-out force for positioning the mooring line 3 .

The mooring lines 3 are divided into four groups, corresponding to the four pontoons 2 respectively. Four sets of mooring lines are respectively connected between the pontoon 3 and the anchoring foundation 4 . The diameter of the mooring line 3 is 167mm, which can be made of steel strands, polyester fiber lines, etc., and the outside is wrapped with rubber sleeves to avoid corrosion and damage in seawater; the upper end is equipped with buoy balls before anchoring, which is convenient for anchoring operations; Each anchor point after anchoring is provided with a maintenance device.

The construction method of the above-mentioned movable offshore wind power floating foundation is carried out according to the following steps:

(1) First, the floating platform and the mooring system are prefabricated on land respectively, and the upper fan tower is installed and stabilized on the floating platform. The floating box 2 on the line surface provides buoyancy stability to realize the overall floating and towing of the floating platform-tower-fan; at the same time, the mooring system is towed and transported to the operating sea area, and the mooring line 3 is provided with buoy balls at the upper end;

(2) After the floating platform and the mooring system installed with the upper fan tower are respectively towed and transported to the operating sea area, water is injected into the sub-chamber inside the anchor foundation through the valve of water vapor replacement, so that the anchor foundation 4 loses its buoyancy. sink, and the anchoring foundation 4 is embedded in the seabed and fixed through the center stacking and internal and external pressure difference;

(3) Connect the four mooring lines 3 to the four pontoons 2 according to the position indicated by the buoy ball, and pre-tension the mooring lines 3 by 10% to 50% to balance the buoyancy of the floating platform and make the mooring lines 3 The berthing line 3 is under tension;

(4) Water is injected into the inner sub-chamber of the floating box 2 through the water-vapor replacement valve, so that the floating platform installed with the upper fan tower loses part of its buoyancy and sinks. During the sinking process, the outer sub-chamber of the floating box 2 The air provides the foundation with a certain buoyancy to ensure the stability of the offshore wind power floating foundation; when the floating platform sinks to the design draft position, the mooring line 3 reaches the preset length, and the remaining 50% to 90% of the mooring line 3 is completed. pretension to balance the buoyancy of the floating platform;

(5) The water body in the sub-chamber of the inner layer of the floating tank 2 is discharged through the valve of water vapor replacement to ensure that the floating foundation of offshore wind power has a certain floating stability;

(6) After being in place, adjust the position of the center of gravity of the offshore wind power floating foundation by injecting water into the outer compartment of the floating box 2 to ensure the safe and stable operation of the offshore wind power floating foundation;

(7) When it is necessary to migrate the offshore wind power floating foundation, water is injected into the sub-chamber in the inner layer of the floating tank 2 through the valve of water-vapor replacement, so that the floating platform with the fan tower installed loses part of its buoyancy and sinks, and the system is cancelled. The tension of the mooring line 3 separates the pontoon 2 from the mooring line 3;

(8) Remove the central stacking of the anchoring foundation 4, and gradually discharge the water in the sub-chamber inside the anchoring foundation through the valve of water vapor replacement, so that the anchoring foundation 4 floats to the sea surface by buoyancy;

(9) Tow the floating platform and mooring system with the fan tower installed to the target sea area, and install and operate again.

The serial numbers themselves, such as "first", "second", etc., for the components herein are only used to distinguish the described objects, and do not have any order or technical meaning. The "connection" and "connection" mentioned in this application, unless otherwise specified, include both direct and indirect connections (connections). In the description of the present invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", The orientation or positional relationship indicated by "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description , rather than indicating or implying that the indicated device or element must have a particular orientation, be constructed and operate in a particular orientation, and therefore should not be construed as limiting the invention.

In the present invention, unless otherwise expressly specified and limited, a first feature "on" or "under" a second feature may be in direct contact between the first and second features, or the first and second features indirectly through an intermediary touch. Also, the first feature being "above", "over" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is level higher than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature has a lower level than the second feature.

The present invention has been exemplarily described above. It should be noted that, without departing from the core of the present invention, any simple deformation, modification, or other equivalent replacements that can be performed by those skilled in the art without any creative effort fall into the scope of the present invention. The scope of protection of the invention.

Claims (10)

1. A migratory offshore wind power floating foundation is characterized in that: comprises a floating platform and a mooring system;

the floating platform comprises a stand column and a plurality of floating boxes; the buoyancy tanks are radially and symmetrically arranged around the lower part of the upright post; a first compartment plate is arranged in the buoyancy tank, the first compartment plate divides the interior of the buoyancy tank into a plurality of compartments, and each compartment is provided with a valve capable of carrying out water-gas replacement;

the mooring system comprises an anchoring foundation and a plurality of groups of mooring lines;

four vertically-arranged partition plates are arranged in the anchoring base, a central stacking groove is defined by the interior of each partition plate, a cabin is formed between each partition plate and the outer wall of the anchoring base, a second cabin plate is arranged in each cabin, the second cabin plate divides each cabin into a plurality of sub-cabins, and each sub-cabin is provided with a valve capable of carrying out water-gas replacement; an inner apron plate and an outer apron plate are arranged at the bottom of the anchoring foundation;

each group of mooring lines corresponds to a buoyancy tank, the upper end of each buoyancy tank is connected with the bottom of the buoyancy tank, and the lower end of each mooring line is connected with the upper surface of the anchoring foundation.

2. The transportable offshore wind power floating foundation of claim 1, wherein: the upper end of the upright post is connected with the fan tower cylinder through a flange.

3. The transportable offshore wind power floating foundation of claim 1, wherein: the upright post is of a cylindrical structure with a cavity, the diameter is 6-10m, the height is 15-25m, and the wall thickness is 50-100 mm.

4. The transportable offshore wind power floating foundation of claim 1, wherein: the flotation tanks are 4 in number and are arranged in a cross shape, and the upright posts are positioned at the centers of the cross shapes.

5. The transportable offshore wind power floating foundation of claim 1, wherein: the length of the buoyancy tank is 8-12m, the width is 3-7m, the height is 5-9m, and the wall thickness is 10-20 mm.

6. The transportable offshore wind power floating foundation of claim 1, wherein: the first compartment plate is arranged along the vertical direction and divides the buoyancy tank into an inner compartment and an outer compartment.

7. The transportable offshore wind power floating foundation of claim 1, wherein: the cross section of the foundation of the sinking pad is square, and the side length is 20-30 m.

8. The transportable offshore wind power floating foundation of claim 1, wherein: the cross section of the central stacking groove is square, the side length is 8-12m, and the height is 4-6 m.

9. The transportable offshore wind power floating foundation of claim 1, wherein: the height of the inner apron board and the outer apron board is 4-6 m.

10. A method for operating a transportable offshore wind power floating foundation is characterized by comprising the following steps:

firstly, prefabricating the floating platform and the mooring system on land respectively, stably mounting a fan tower cylinder on the floating platform, towing and transporting the floating platform provided with the fan tower cylinder to an operation sea area, towing and transporting the mooring system to the operation sea area, and arranging a buoy ball at the upper end of a mooring line to enable the upper end of the mooring line to float on the water surface;

injecting water into the sub-compartments of the anchoring foundation through a water-gas replacement valve to enable the anchoring foundation to lose buoyancy and sink, and embedding the anchoring foundation into the seabed for fixation in a central stacking and internal-external pressure difference mode;

anchoring the upper end of the mooring line to the buoyancy tank according to the indicated position of the buoy ball, and performing 10% -50% pretensioning on the mooring line to balance the buoyancy of the floating platform and enable the mooring line to be in a tensioned state;

injecting water into the sub-cabin chamber inside the buoyancy tank through a water-gas replacement valve to enable the floating platform provided with the fan tower barrel to lose part of buoyancy and sink, and when the floating platform sinks to a designed draft position, pre-tensioning the remaining 50% -90% of mooring lines to balance the buoyancy of the floating platform;

fifthly, adjusting the gravity center and the floating center position of the offshore wind power floating foundation by injecting water or pumping water into the sub-chambers of the floating box;

step six, when the offshore wind power floating foundation is transferred, injecting water into a sub-cabin chamber in the buoyancy tank through a water-gas replacement valve, so that the floating platform provided with the fan tower cylinder loses part of buoyancy and sinks, and the tension of the mooring line is cancelled to separate the buoyancy tank from the mooring line;

removing the center pile load of the anchoring foundation, and gradually discharging the water body in the sub-cabins of the anchoring foundation through a water-gas replacement valve to enable the anchoring foundation to float up to the sea surface through buoyancy;

and step eight, towing and transporting the floating platform provided with the fan tower drum and the mooring system to a target sea area, and then installing and operating again.

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