Offshore wind turbine frame manufacturing work ship

Abstract

To construct a frame foundation at an installation site on the ocean without requiring a large ship for carrying an assembled frame foundation and without requiring a work ship having a large crane.SOLUTION: A work ship for manufacturing a floating body type frame foundation for installing a windmill for wind power generation on the ocean includes: a stern part having a two-forked structure divided into a starboard side and a port side; a lifter arranged in a space opened on a sea surface of the stern part and capable of mounting a frame foundation during manufacture; and a crane for transferring a concrete form and a reinforcement cage on a deck.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] An embodiment of the present invention relates to a work vessel for fabricating a frame for an offshore wind turbine. [Background technology]

[0002] In recent years, there has been a worldwide shift away from fossil energy sources such as coal and oil to renewable energy sources, and against this backdrop, the construction of wind turbines for wind power generation is becoming widespread. Among these, offshore wind turbines, which are installed on the ocean, are attracting attention. With offshore wind turbines, the wind turbine and generator are installed on a mounting foundation structure installed underwater. Offshore wind turbines have the advantage that there are many locations suitable for generating electricity, and they can generate electricity stably.

[0003] When installing offshore wind turbines, the mounting foundation structure assembled on land, the nacelle containing the wind turbine blades and the gearbox, etc. are transported by ship to the installation area, and installation work is carried out using a work boat equipped with a crane. At the installation site, a jack-up type (self-elevating barge) work boat like those used for oil drilling is often used.

[0004] Conventionally, the installation of offshore wind turbines requires a ship to transport the mounting base structure and a work boat to be used for offshore construction. As the water depth increases, larger ships are also required to transport the mounting base structure.

[0005] In view of this, in recent years, a method has been proposed in which the frame foundation is made into a floating structure and towed while floating to the installation position (Patent Document 1). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2013-170493 A DISCLOSURE OF THEINVENTION [Problem to be solved by the invention]

[0007] As described above, conventionally, construction of offshore wind turbines requires transport ships and work boats, and the increase in ship charter costs as wind turbines become larger and the water depth increases has become an issue.

[0008] The present invention has been made in consideration of the problems associated with the above-mentioned conventional technology, and has an object to provide a frame manufacturing work vessel for offshore wind turbines that enables the frame foundation to be constructed at the installation site offshore, without the need for a large ship to transport the assembled frame foundation, and without the need for a work vessel equipped with a large crane. [Means for solving the problem]

[0009] In order to achieve the above-mentioned objective, an offshore wind turbine frame manufacturing work vessel according to one embodiment of the present invention is a work vessel for manufacturing floating frames for installing wind turbines for wind power generation on the ocean, and is characterized by having a stern section with a bifurcated structure divided into starboard and port sides, an elevator that is placed in the space open to the sea surface at the stern section and is capable of loading the frame foundations in the process of being manufactured, and a crane that transports concrete formwork and reinforcing bar cages on the deck.

[0010] In addition, a method for installing a frame for an offshore wind turbine according to an embodiment of the present invention includes the steps of: using a frame fabrication work ship, pouring concrete on the lifting platform to add to one small section of the frame foundation; After constructing the small section, the lifting platform is lowered by a distance equivalent to the small section, and the platform foundation being constructed is lowered into the sea. This step is repeated. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a diagram showing an overview of an offshore wind turbine and a frame manufacturing work ship according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a front view showing a base on which a wind turbine for wind power generation is mounted. [Diagram 3] 3A is a plan view of the frame fabrication work boat, FIG. 3B is a side view thereof, and FIG. 3C is a front view thereof. [Figure 4]13A to 13C are diagrams showing the process of manufacturing the bottom of the rack foundation. [Diagram 5] 5 is a diagram showing a process of adding a small section above the bottom cap produced in FIG. 4. [Figure 6] 13A and 13B are diagrams showing a process of lowering the manufactured intermediate structure of the frame foundation into the sea using a lift. [Figure 7] This shows the pouring of concrete for the next second level of sub-sections. [Figure 8] FIG. 13 shows the process of properly pouring weight concrete onto the bottom cap. [Figure 9] FIG. 13 is a diagram showing the process of adding weight concrete. [Figure 10] FIG. 13 is a diagram showing a process of injecting water as a weight into the intermediate structure of the extended base foundation. [Figure 11] FIG. 13 shows the process of manufacturing the top section of the platform foundation. [Figure 12] 13A and 13B are diagrams showing a process of detaching the frame fabrication work ship from the frame foundation. BEST MODE FOR CARRYING OUT THEINVENTION

[0012] Hereinafter, an embodiment of an offshore wind turbine frame manufacturing work ship according to the present invention will be described with reference to the accompanying drawings. Fig. 1 is a diagram showing an overview of an offshore wind turbine and a frame fabrication work ship according to an embodiment of the present invention. In Fig. 1, reference number 12 indicates a frame foundation that supports the wind turbine on the sea. Reference number 11 indicates the sea surface. Reference number 14 indicates a frame fabrication work ship.

[0013] In this embodiment, the frame foundation 12 is constructed by pouring concrete on the frame fabrication work ship 14. This differs from the conventional construction method in which the frame foundation 12 is fabricated on land. On the frame fabrication work ship 14, the frame foundation 12 is fabricated by adding small sections at a time, so the frame fabrication work ship 14 is provided with the necessary facilities for this purpose.

[0014] 1 shows a completed platform foundation 12 installed in a floating state on a location. The bottom of the platform foundation 12 is connected to an anchor 16 by an anchor chain 15. The platform foundation 12 is a long, hollow cylindrical structure. The length of the platform foundation 12 varies depending on the water depth, but in this embodiment, it is assumed to be about 50 meters long.

[0015] As shown in Fig. 1, the frame foundation 12 is a floating type frame that floats in a vertical position. A concrete weight 84 is attached to the bottom. The upper end of the frame foundation 12 protrudes from the sea surface 11, and as shown in Fig. 2, a wind turbine 10 for wind power generation is installed on it. The wind turbine 10 has a nacelle 19 and wind turbine blades 20 at the top of a tower 18.

[0016] Next, the frame fabrication work boat 14 will be described with reference to FIG. FIG. 3(A) is a plan view showing the frame fabrication work boat 14, FIG. 3(B) is a side view thereof, and FIG. 3(C) is a front view thereof. In FIG. 3(A), the bow side and the stern side are as shown in the figure. Facing the direction of travel of the ship, the right side is the starboard side, and the left side is the port side. An office 21 and a generator 23 as a power source are arranged on the deck on the bow side of the frame fabrication work ship 14. The frame fabrication work ship 14 of this embodiment is not a self-propelled ship equipped with an engine, but a so-called barge-type ship. When moving, it is towed. Rails 22A and 22B for a crane are laid on the starboard and port sides of the deck. Reference number 24 is a gantry crane. The gantry crane 24 can move on the deck from the stern to the bow side along the rails 22A and 22B.

[0017] As shown in Fig. 3(A), the hull is divided into two parts from the center to the stern, and a space open to the sea surface is provided between the starboard-side hull 23A and the port-side hull 23B. The center of the deck is a work area 24 where concrete forms 81 for the small sections of the platform foundation 12 are fabricated. On the stern side of the deck, a work platform 25 is spanned between the starboard-side hull 23A and the port-side hull 23B, and this work platform 25 forms a work area 26 where reinforcing bar cages 82 for each small section of the platform foundation 12 are assembled.

[0018] As shown in Figures 3(B) and 3(C), the gantry crane 24 has a gantry frame consisting of legs 31 and a beam 32. A hoisting machine 33 is installed on the beam 32 so as to be capable of traveling in the longitudinal direction of the beam 32. A hoisting device 35 is suspended from the hoisting machine 33 via a wire rope 34.

[0019] Between the work area 24 for making concrete forms and the work area 26 for assembling rebar, an elevator 30 is installed. This elevator 30 is used for pouring concrete, curing the concrete, and also for joining the completed sections together and lowering them into the sea.

[0020] In this elevator 30, concrete frames and reinforcing bars are placed on the elevator platform 38, and concrete is poured and cured. The elevator platform 38 is raised and lowered by four hoists 40. In Fig. 3(A), 32a and 32b are holding devices that fix and hold the frame base in the process of being manufactured.

[0021] The frame manufacturing work ship for offshore wind turbines according to this embodiment is configured as described above. Next, a construction method for installing a foundation structure using this frame manufacturing work ship will be described. Figure 4 shows the process of manufacturing the bottom 13 (see Figure 2) of the frame foundation 12. Of these, Figure 4(A) shows a state in which a bottom cap 42 made of a steel plate is placed on the lift platform 38 of the lift 30 and a reinforcing bar cage 40 is installed on this bottom cap 40, and Figure 4(B) shows the process of pouring concrete into the bottom cap 38.

[0022] The initial position of the platform 38 is below the deck level and above sea level 11. The bottom cap 38 and the reinforcing bar cage 40 are each carried to the platform 38 by the gantry crane 24. As shown in Figure 4 (B), when pouring concrete, a concrete supply pipe 80 is extended from a batcher ship (not shown) to directly above the bottom cap 38, and concrete is poured in. In the work area 24 for making concrete forms, while the concrete is curing, a concrete form 81 to be used for making the next small section is prepared, and in the work area 26 for assembling reinforcing bars, a reinforcing bar cage 82 to be used for the next small section is prepared.

[0023] Next, Fig. 5 is a diagram showing a process of adding a small section one above the bottom cap 42 produced in Fig. 4. Among these, Fig. 5(A) is a diagram showing a state in which a concrete formwork 81 is attached to a reinforcing bar cage 82. The concrete formwork 81 is carried by a gantry crane 24 and placed outside the reinforcing bar cage 40. 5(B) is a diagram showing a process of pouring concrete into a concrete formwork 81. Concrete is supplied from a supply pipe 80 of the batcher ship.

[0024] Figure 6 shows the process of lowering the fabricated intermediate structure 100 of the platform foundation into the sea by the elevator 30. Figure 6(A) shows the state after the concrete formwork 81 has been removed. Figure 6(B) shows the state after the elevator platform 38 of the elevator 30 has descended and the bottom cap 42 of the platform foundation has been submerged in the sea. By lowering the intermediate structure 100 of the platform foundation into the sea in this manner, it becomes possible to fabricate the next subdivision on board the ship.

[0025] Fig. 7 shows the pouring of concrete for the next, second-tiered subdivision. Fig. 7(A) shows the process of joining a reinforcing bar cage 82 and a concrete formwork 81 to the subdivision below and pouring concrete. Fig. 7(B) shows the intermediate structure 100 of the platform foundation after the concrete has been cured and the formwork 81 has been removed.

[0026] In constructing the platform foundation, a process of adding small sections to the intermediate structure 100 of the platform foundation on board the ship and lowering it into the sea is repeated. The intermediate structure 100 is hollow inside, so buoyancy equivalent to the displacement occurs. To cancel the buoyancy, weight concrete 70 is appropriately poured on the bottom cap 42 as shown in FIG. 8. In FIG. 8(A), the intermediate structure 100 of the platform foundation has been lowered into the sea by one added small section from the position shown in FIG. 7. FIG. 8(B) shows the process of pouring concrete from the supply pipe 80 of the voucher ship into the intermediate structure 100 and pouring weight concrete 84.

[0027] In this way, as the intermediate structure 100 of the base foundation is extended while successively adding small sections, the buoyancy generated becomes even greater and the weight concrete 84 becomes insufficient. Therefore, weight concrete 84 is added as appropriate, as shown in Fig. 9. Fig. 9(A) shows the process of pouring the additional weight concrete, and Fig. 9(B) shows the state in which the lift platform 38 of the lift 30 has descended by one small section, and the intermediate structure 100 has been lowered into the sea to the position where the concrete for the next small section will be poured.

[0028] 10 shows the process of pouring water 86 as a weight into the extended intermediate structure 100 of the base. The amount of concrete used as a weight is calculated including the amount of the wind turbine, so at this stage when the wind turbine is not mounted, there is excess buoyancy. Therefore, the amount of water required for balance is poured after accurate buoyancy calculations.

[0029] Fig. 11 is a diagram showing the process of manufacturing the top section of the frame foundation, in which a formwork 87 and a reinforcing bar cage 88 are installed at the top and concrete is poured.

[0030] After going through the above steps, the construction of the frame foundation 12 by pouring concrete on board the ship is completed. Here, Fig. 12 is a diagram showing the process of detaching the frame fabrication work ship 14 from the frame foundation 12. Among these, Fig. 12(A) shows a state in which the completed frame foundation 12 is placed on the lifting platform 38. In this state, the lifting platform 38 cannot be retrieved, and the frame fabrication work ship 14 cannot be detached.

[0031] Therefore, the water 86 inside the frame foundation 12 is forcibly discharged by the submersible pump 92. When the water has been discharged, the frame foundation 12 floats up due to increased buoyancy, as shown in Figure 12 (B). If the hull is moved forward in this state, the stern opens into a bifurcated structure, making it possible to detach. The lifting platform 38 is then hoisted up and retrieved. The completed platform foundation 12 is connected to an anchor 16 via an anchor chain 15 as shown in FIG.

[0032] As described above, according to this embodiment, there is no need to transport the platform foundation fabricated on land by ship or perform the complicated work of erecting it vertically in the sea, as in the conventional method. Instead, the floating platform foundation can be efficiently installed by adding small sections at a time on the platform fabrication work ship.

[0033] The offshore wind turbine frame fabrication work ship according to the present invention has been described above with reference to a preferred embodiment, but this embodiment is given as an example and is not intended to limit the scope of the invention. Of course, the novel apparatus, method, and system described in the specification can be embodied in various forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. The claims and their equivalents are intended to cover the embodiments or improvements thereof within the spirit of the invention. [Explanation of symbols]

[0034] 10...wind turbine, 11...sea surface, 12...frame foundation, 14...frame manufacturing work ship, 17...weight, 18...tower, 19...nacelle, 20...turbine blade, 21...office, 22A, 22B...rail, 24...gantry crane, 23A...starboard side hull, 23B...port side hull, 24...work area, 26...work area, 30...lifting machine, 31...leg, 32...beam, 33...hoisting machine, 34...wire rope, 35...sling, 38...lifting platform, 40...hoisting machine, 42...bottom cap, 81...concrete formwork, 82...reinforcing bar cage, 100...intermediate structure

Claims

1. A work vessel that manufactures floating foundations for installing wind turbines for wind power generation on the ocean, A stern section with a bifurcated structure split into starboard and port sides; an elevator, the elevator being disposed in a space open to the sea surface of the stern and including a lift platform that can be raised and lowered; A crane for transporting concrete forms and reinforcing bar cages on the deck; The lift platform can be lowered into the sea together with the platform base, and the platform base can be raised An offshore wind turbine frame manufacturing work vessel that can be rolled up and retrieved while floating.

2. A work vessel that manufactures floating foundations for installing wind turbines for wind power generation on the ocean, A stern section with a bifurcated structure split into starboard and port sides; an elevator, the elevator being disposed in a space open to the sea surface of the stern and including a lift platform that can be raised and lowered; A crane for transporting concrete forms and reinforcing bar cages on the deck; The stern section includes a port hull and a starboard hull, An offshore wind turbine frame manufacturing work vessel, characterized in that a space between the port side hull and the starboard side hull opens vertically into the sea.

3. A work vessel that manufactures floating foundations for installing wind turbines for wind power generation on the ocean, A stern section with a bifurcated structure split into starboard and port sides; an elevator, the elevator being disposed in a space open to the sea surface of the stern and including a lift platform that can be raised and lowered; A work vessel for constructing the offshore wind turbine frame is used, which is equipped with a crane on the deck to transport concrete formwork and rebar cages. a step of adding one small section of the platform foundation by pouring concrete on the lift platform; After constructing the small section, lowering the lifting platform by a distance corresponding to the small section, and lowering the frame foundation under construction into the sea; This is a method for installing frames for offshore wind turbines, characterized by repeating the above steps.

4. 4. The method for installing a frame for an offshore wind turbine according to claim 3, further comprising placing a concrete weight on a bottom of the frame foundation during construction.

5. 4. The method for installing an offshore wind turbine according to claim 3, wherein water is poured as a weight in accordance with a balance between the weight of the frame foundation and buoyancy.

6. The offshore wind turbine frame installation method according to claim 5, characterized in that the water used as the weight is drained in order to detach the frame fabrication work ship from the completed frame foundation.

Images