A combined foundation suitable for energy storage and anchoring of floating wind turbines in deep-sea areas

Abstract

This invention discloses a combined foundation suitable for energy storage and anchoring of floating wind turbines in deep-sea areas. The combined foundation comprises several foundation units, each primarily composed of caissons, which are fixed to the seabed by micro-steel piles. The caissons are hollow inside and interconnected via pipelines, forming an expandable energy storage space. The floating wind turbine system is anchored to the foundation units via mooring lines. A hydrogen production system is installed on the floating wind turbine platform, and the liquid hydrogen produced by this system is transported through pipelines and stored in the energy storage space. This invention provides a large energy storage capacity while maintaining low construction difficulty and cost.

Description

Technical Field

[0001] This invention relates to offshore wind power generation devices, specifically to a combined foundation suitable for energy storage and anchoring of floating wind turbines in deep-sea areas. Background Technology

[0002] The deep-sea region is rich in wind energy resources and has great development potential. However, the complex sea conditions in the deep-sea region result in high costs and significant construction difficulties for offshore wind power projects.

[0003] Currently, floating wind turbines are the main form of offshore wind power generation in waters deeper than 50 meters. The upper part of the floating wind turbine system is mostly anchored to the seabed by mooring lines. Due to the long distance from the shore, traditional submarine cable power transmission methods cannot be implemented.

[0004] To address the challenges of offshore power transmission, floating wind turbine systems combining hydrogen production and energy storage technologies have been proposed, such as CN115977878A and CN113335468B. These solutions convert the generated electricity into hydrogen energy for storage through a supporting hydrogen production system. However, existing solutions place the energy storage system on the floating foundation of the floating wind turbine system. Due to the limited size of the floating foundation, the energy storage space that can be provided is also relatively limited.

[0005] Therefore, how to construct larger energy storage spaces on the complex seabed environment of the deep sea with lower costs and less construction difficulty is an urgent problem to be solved. Summary of the Invention

[0006] Purpose of the invention: The purpose of this invention is to provide a combined foundation for energy storage and anchoring of floating wind turbines in deep sea areas. This foundation can be used to construct larger and expandable energy storage space on complex seabed topography in deep sea areas, solving the current problems of high power transmission costs and insufficient absorption capacity in deep sea areas. At the same time, it is easy to construct and has low cost.

[0007] Technical Solution: The combined foundation for energy storage and anchoring of floating wind turbines in deep-sea areas, as described in this invention, comprises several foundation units, each consisting of a caisson. The caissons are fixed to the seabed by micro-steel piles. The caissons are hollow inside and interconnected by pipelines to form an expandable energy storage space. The floating wind turbine system is anchored to the foundation units by mooring lines. A hydrogen production system is installed on the floating wind turbine platform. The liquid hydrogen produced by the hydrogen production system is transported through pipelines and stored in the energy storage space.

[0008] Furthermore, the foundation unit connected to the mooring line and the transport pipeline has micropiles of greater size and depth of penetration than the micropiles on other foundation units.

[0009] Furthermore, the micro steel piles use linear variable cross-section steel pipes that are thicker at the top and thinner at the bottom, and the caisson is equipped with matching fixing holes; when the linear variable cross-section steel pipes are driven into the design depth, they maintain close contact with the fixing holes.

[0010] Furthermore, liquid hydrogen has a much smaller mass than water, and its injection into the underlying foundation will generate enormous buoyancy. Therefore, grouting holes are arranged in the wall of the linear variable cross-section steel pipe, with a sealed tip at the lower end of the pipe housing these holes. Once the pipe is driven to the designed depth, grouting is used to bond the pipe to the fixed holes, forming a composite foundation on the seabed that provides better load-bearing capacity.

[0011] Furthermore, a steel cap with a pre-reserved grouting hole is provided at the upper end of the linear variable cross-section steel pipe.

[0012] Furthermore, the pipeline uses flexible sleeves.

[0013] Furthermore, the basic units constituting the combined foundation are arranged in a regular pattern.

[0014] Furthermore, the basic unit is rectangular, and the combined foundation is a rectangular array structure.

[0015] Furthermore, the basic unit is fan-shaped, and the combined foundation is a concentric ring structure.

[0016] Furthermore, the combined system incorporates multiple floating wind turbine systems via mooring anchors.

[0017] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages:

[0018] This invention uses several basic units to form a combined foundation for energy storage and anchoring of floating wind turbines. It can overcome the problem of uneven settlement of the foundation caused by the uneven topography of the deep seabed. It is scalable, suitable for large-scale integration, and can form a huge energy storage space.

[0019] The foundation unit adopts a caisson + micro steel pile structure, which has low construction difficulty and cost, and the combined foundation has good overall bearing capacity.

[0020] The deep seabed has a natural high-pressure and stable low-temperature environment, which is conducive to the storage of liquid hydrogen. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of a combined foundation for energy storage and anchoring of floating wind turbines in deep-sea areas, provided in an embodiment of this application.

[0022] Figure 2 This is a schematic diagram of the structure of the basic unit in the embodiments of this application;

[0023] Figure 3 This is a schematic diagram of the structure of the micro steel pile in the embodiments of this application;

[0024] Figure 4 This is a schematic diagram of another combined foundation for energy storage and anchoring of floating wind turbines in deep-sea areas, provided in the embodiments of this application. Detailed Implementation

[0025] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0026] In this embodiment, the proposed wind farm is located on a site covered by a thick layer of soft clay, with a seawater depth of 60–80 m.

[0027] like Figure 1 The diagram shown is a structural schematic of a combined foundation for energy storage and anchoring of floating wind turbines in deep-sea applications, provided in an embodiment of this application. The combined foundation has a rectangular array structure, comprising 12 foundation units 2 arranged in 3 rows and 4 columns. Two floating wind turbine systems 1 are anchored on this combined foundation, and a hydrogen production system is installed on the floating wind turbine platform of each system 1.

[0028] Specifically, in combination Figure 2 The basic unit 2 is rectangular and includes a caisson 21. The interior of the caisson 21 is hollow, forming an energy storage space for liquid hydrogen storage. Storage tanks for liquid hydrogen storage are installed within this energy storage space. The caissons 21 are connected to each other via pipelines 22, allowing the energy storage spaces within each caisson 21 to be interconnected, thus forming an expanded energy storage space. The storage tanks located in different caissons 21 are connected by wiring, ensuring both the transmission of forces and the exchange of liquid hydrogen.

[0029] For unconnected pipelines 22, sealing is required to prevent external seawater from entering the caisson 21 and adversely affecting the liquid hydrogen storage tank inside the caisson 21.

[0030] In this embodiment, the basic unit 2 is 8m long, 8m wide, and 10m high. Seawater can provide a natural high pressure of 6-8 MPa and a stable low temperature environment, which is beneficial for the storage of liquid hydrogen.

[0031] To ensure the overall integrity of energy storage and stress distribution in foundation unit 2, and to overcome the problem of uneven settlement caused by the site, the pipeline 22 between foundation units 2 adopts a flexible sleeve with sealing, corrosion resistance, and the ability to transmit shear force and axial force after a certain displacement. Its size, strength and stiffness must meet the design requirements of local stress verification. The liquid hydrogen exchange line between foundation units 2 is run through the inside of the flexible sleeve.

[0032] The caisson 21 is secured to the seabed by multiple microsteel piles 3. Figure 3To facilitate the driving and grouting of the micropile 3, and to ensure good force transmission with the foundation unit 2 through compression, the micropile 3 is constructed from a linear variable cross-section steel pipe 32, which is thicker at the top and thinner at the bottom, with grouting holes 33 arranged in the pipe wall. The lower end of the linear variable cross-section steel pipe 32 is a sealed tip 34 with grouting holes 33 arranged in the pipe wall. To facilitate the driving of the micropile 3, a steel cap 31 with pre-reserved grouting holes 33 is provided at the upper end of the linear variable cross-section steel pipe 32. The caisson 21 is provided with a suitable fixing hole 211. When the linear variable cross-section steel pipe 32 passes through the fixing hole 211 and is driven to the designed depth, the linear variable cross-section steel pipe 32 and the fixing hole 211 are compressed together to maintain close contact.

[0033] Foundation unit 2 consists of multiple micro steel piles 3 driven to a certain depth into the ground. Grouting is then used to bond the linear variable cross-section steel pipe 32 to the fixing hole 211, forming a composite foundation 35 on the seabed. This ensures sufficient force transfer between foundation unit 2, the multiple micro steel piles 3, and the seabed. The uplift force, horizontal force, and overturning moment generated by the floating wind turbine system 1 and the combined foundation are jointly borne by the overall structure formed by the multiple foundation units 2, the micro steel piles 3, and the composite foundation 35, resulting in excellent load-bearing capacity.

[0034] The floating wind turbine system 1 is anchored to the foundation unit 2 via mooring line 11. Liquid hydrogen produced by the hydrogen production system is transported through pipeline 12 and stored in the liquid hydrogen storage tank in the energy storage space. Since the floating wind turbine system 1 transmits force to the combined foundation below via mooring line 11 or pipeline 12, to ensure that the foundation unit 2 can provide sufficient reaction force, the micro-steel piles 3 on the foundation unit 2 connected to the mooring line 11 and pipeline 12 are larger in size and have a greater embedment depth than the micro-steel piles 3 on other foundation units 2, and require separate local stress calculations.

[0035] In this embodiment, the microsteel piles 3 used in the foundation unit 2 where the mooring line 11 or the transport pipeline 12 is located have a maximum diameter of 60cm, a wall thickness of 12mm, and an insertion depth of 8m. The microsteel piles 3 used in other foundation units 2 have a maximum diameter of 40cm, a wall thickness of 8mm, and an insertion depth of 5m.

[0036] Calculations show that the combined foundation provided in this embodiment can provide 7680m³ of space for hydrogen production and energy storage. 3 The space can store 54.4 tons of liquid hydrogen, which greatly increases the energy storage space of deep-sea floating wind turbines and solves the problem of energy storage and anchoring of multiple floating wind turbines in the wind power area.

[0037] It should be noted that the shape of basic unit 2 is not limited to a rectangle and can be adjusted according to site conditions and design requirements. For example... Figure 4This is a schematic diagram of a combined foundation for energy storage and anchoring of a floating wind turbine in deep sea, provided as an embodiment of this application. The combined foundation is a concentric ring structure, and the foundation unit 2 is fan-shaped.

[0038] Furthermore, the steel cap 31 of the micropile 3 can be removed depending on the actual piling situation. If the micropile 3 can provide sufficient bearing capacity, grouting may not be necessary.

Claims

1. A combined foundation for energy storage and anchoring of floating wind turbines in deep-sea areas, characterized in that, The system includes several foundation units (2) whose main body is a caisson (21). The caisson (21) is fixed to the seabed by micro steel piles (3). The caisson (21) is hollow inside and connected to each other by pipelines (22) to form an expandable energy storage space. The unconnected pipelines (22) are sealed to prevent seawater from entering the caisson (21). The pipelines (22) are made of flexible sleeves with sealing, corrosion resistance and the ability to transmit shear force and axial force after a certain displacement. Liquid hydrogen storage tanks located in different caissons (21) are connected by lines, which are installed inside the flexible sleeves. The floating wind turbine system (1) is anchored to the foundation unit (2) by mooring line (11). The floating wind turbine platform is equipped with a hydrogen production system. The liquid hydrogen produced by the hydrogen production system is transported through the delivery pipeline (12) and stored in each liquid hydrogen storage tank.

2. The combined foundation according to claim 1, characterized in that, The foundation unit (2) connected to the mooring line (11) and the transport pipeline (12) has micro steel piles (3) with larger dimensions and deeper penetration into the ground than the micro steel piles (3) on other foundation units (2).

3. The combined foundation according to claim 1 or 2, characterized in that, The micro steel pile (3) adopts a linear variable cross-section steel pipe (32) with a thicker top and a thinner bottom, and the caisson (21) is provided with a suitable fixing hole (211); when the linear variable cross-section steel pipe (32) is driven into the design depth, it maintains close contact with the fixing hole (211).

4. The combined foundation according to claim 3, characterized in that, The linear variable cross-section steel pipe (32) has grouting holes (33) arranged on its pipe wall. The lower end of the linear variable cross-section steel pipe (32) is a sealed tip (34) for grouting holes (33). When the linear variable cross-section steel pipe (32) is driven into the design depth, grouting is used to bond the linear variable cross-section steel pipe (32) to the fixed hole (211) and form a composite foundation (35) on the seabed.

5. The combined foundation according to claim 4, characterized in that, A steel cap (31) with a reserved grouting hole (33) is provided at the upper end of the linear variable cross section steel pipe (32).

6. The combined foundation according to claim 1, characterized in that, The basic units (2) constituting the combined foundation are arranged in a regular manner.

7. The combined foundation according to claim 6, characterized in that, The basic unit (2) is rectangular, and the combined basic unit is a rectangular array structure.

8. The combined foundation according to claim 6, characterized in that, The basic unit (2) is fan-shaped, and the combined basic unit is a concentric ring structure.

9. The combined foundation according to claim 1, characterized in that, Based on the combined structure, multiple floating wind turbine systems (1) are anchored by mooring lines (11).

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