Spar type floating body, and spar type floating body erection method

Abstract

To provide a spar type floating body which can be erected easily at a low cost, and a method for erecting the spar type floating body.SOLUTION: A columnar body 110 is equipped with a water pipe 120 and opening / closing means 130, and is arranged so that the water pipe is on a seawater side, the columnar body floats on a sea surface in a "sideways position" inclined so that an intake 120E is located in seawater, when the opening / closing means is opened in the sideways position, seawater flowing in from the intake is poured into the inside of the columnar body from a drain port 120D through the water pipe, and the columnar body is erected while a bottom part of the columnar body is submerged in the sea and a column axis is tilted closer to vertical.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an offshore wind power generation facility, and more specifically to a spar-type float that can naturally inject seawater into its interior by utilizing gravity, and a method for erecting the spar-type float. [Background technology]

[0002] Although electricity consumption in Japan temporarily began to decline due to the impact of the global financial crisis in 2008, it has been increasing continuously since the oil shock of 1973, expanding 2.6-fold between fiscal 1973 and 2007. The reasons for this include the spread of so-called home appliances such as air conditioners and electric carpets as living standards improve, and the spread of office automation (OA) equipment and communication devices as the number of office buildings increases.

[0003] Until now, this enormous demand for electricity has mainly been met by power generation using so-called fossil fuels such as oil, coal, and natural gas. However, in recent years, attention has been focused on the depletion of fossil fuels and environmental issues associated with global warming, and power generation methods have gradually changed in response. As a result, according to statistics from the Federation of Electric Power Companies of Japan, while the annual amount of electricity generated by oil accounted for about 46% of the total around 1980, by 2010 this proportion had fallen to 9%. Instead, nuclear power generation has increased, accounting for just over 25% of the total (2010). Nuclear power generation has a significant effect on reducing greenhouse gas emissions compared to conventional power generation methods, and can provide electricity at low cost, making it a major contributor to Japan's electricity demand.

[0004] Furthermore, power generation methods using renewable energy sources have come to be adopted due to their ability to reduce greenhouse gas emissions, and in 2020, they accounted for approximately 12% of total annual power generation (Federation of Electric Power Companies). This renewable energy is literally energy that can be reproduced, such as solar, wind, geothermal, small and medium-sized hydroelectric power, and woody biomass, and is seen as a promising source of low-carbon energy as it reduces greenhouse gas emissions and can be produced domestically.

[0005] Among renewable energies, wind power generation has the advantage of high conversion efficiency of electrical energy. In general, the conversion efficiency of solar power generation is about 20%, woody biomass power generation is about 20%, and geothermal power generation is 10-20%, while wind power generation is 20-40%, so it can convert energy into electricity more efficiently than other power generation methods. Another feature of wind power generation is that, unlike solar power generation, it can generate electricity both day and night. Due to these characteristics, wind power generation is already widely used as a major power generation method in Europe, and in Japan, as part of its "energy mix" initiative, it aims to account for 1.7% of the power source mix by 2030.

[0006] Wind power generation can be broadly divided into onshore and offshore wind power generation depending on where it is installed, with onshore wind power generation being easier to install than offshore wind power generation, and therefore having the advantage of being able to keep costs down. On the other hand, offshore wind power generation does not have the noise problems that onshore wind power generation has, and the risk of damage from falling over can be avoided, and above all, it has the advantage of being able to obtain greater wind power stably than on land. Japan, which has the sixth largest exclusive economic zone in the world, is an ideal location for offshore wind power generation, and is thought to have the potential to become a promising producer of renewable energy in the future.

[0007] Also, different types of offshore wind turbines are adopted depending on the installation location, with bottom-fixed offshore wind turbines being suitable for sea areas shallower than 50m, and floating offshore wind turbines being suitable for sea areas deeper than 50m. Of these, floating offshore wind turbines use floats that float on seawater, and generate electricity by installing a power generation mechanism on the float connected by mooring lines. Float types include barge type, semi-submersible type, spar type, and tension leg platform (TLP). Of these, spar type offshore wind turbines are considered advantageous in terms of float manufacturing costs, since the structure of the spar type float is not very complicated, which reduces the labor required for manufacturing, and the spar type float is lightweight, which reduces the material cost.

[0008] FIG. 10 is a side view showing a schematic diagram of a spar-type offshore wind power generation facility. As shown in this figure, a spar-type offshore wind power generation facility is composed of a spar-type float floating in the sea, and a tower, rotor, nacelle, etc. (hereinafter, these are collectively referred to as the "wind turbine unit") installed on the spar-type float. The tower is a structure that supports the rotor and nacelle, and the spar-type float functions as the foundation of the tower. The rotor, which is made up of blades and a hub, converts wind into power, and the nacelle, which includes a gearbox, generator, transformer, etc., converts the power into electricity, which is transmitted to land via power cables (dynamic cable and undersea cable). The spar-type float is generally moored by the weight of a catenary-shaped mooring rope.

[0009] The main body of the spar-type float is a long body whose axial dimension (hereinafter referred to as "column axis") is larger than its cross-sectional dimension, and has a hollow tubular shape. As shown in Fig. 10, the spar-type float is in a state where its column axis direction is approximately vertical (including vertical) (hereinafter referred to as "upright state") during operation. Normally, this spar-type float is manufactured on land such as in a dry dock, and therefore needs to be transported by sea to the operation area (wind farm area: WF area). Although there are some examples of transporting spar-type floats in an upright state in some places such as Northern Europe, in Japan, where the water depth around land is shallow, the spar-type float is transported with its column axis direction approximately horizontal.

[0010] Therefore, to put it into an operational state, the spar-type float needs to be rotated from a nearly horizontal state to an upright state (hereinafter referred to as "erecting"). Since the WF area is expected to be subject to considerable wind and wave forces, erecting the spar-type float is not easy, and it is common for it to be erected in a pre-selected calm area. The wind turbine unit is manufactured separately from the spar-type float and transported to the calm area, where it is installed on the erected spar-type float using a crane ship or similar. The structure, which is largely completed as an offshore wind power generation facility, is then transported to the WF area in its operational state (i.e., with the spar-type float in an upright position).

[0011] Conventionally, when erecting a spar-type float, a high-output pump is used to inject ballast water (e.g., seawater) into the main body of the spar-type float, and the weight of the ballast water accumulating inside is used to erect the float, as shown in Patent Document 1. In addition, as shown in Patent Document 2, a technology has been proposed for erecting a spar-type float easily and at low cost without relying on a high-output pump. [Prior art documents] [Patent documents]

[0012] [Patent Document 1] JP 2012-201217 A [Patent Document 2] JP 2022-014509 A Summary of the Invention [Problem to be solved by the invention]

[0013] FIG. 11 is a step diagram showing the conventional procedure for erecting a spar-type float. With reference to this figure, the conventional procedure for erecting a spar-type float will be described. First, as shown in FIG. 11(a), the spar-type float manufactured in a dry dock or the like is transported by a tugboat to the sea in a preselected calm area. When the spar-type float is transported to the target calm area, seawater is injected into the main body using a pump as shown in FIG. 11(b). Since a weight made of concrete or the like is provided at the bottom of the spar-type float, the bottom side of the spar-type float is in a slightly sunken and inclined state before the start of seawater injection. Therefore, as the injection of seawater progresses, the angle of inclination (the intersection angle between the horizontal plane and the column axis direction of the spar-type float) increases as shown in FIG. 11(c), and finally the spar-type float becomes upright as shown in FIG. 11(d). Then, seawater injection is further advanced from the state shown in FIG. 11(d) to sink the spar-type float until the planned draft is obtained.

[0014] The spar-type floats that make up the floating offshore wind power generation facility have a considerable diameter and axial length, and therefore cannot be submerged to the designed draft unless a considerable amount of seawater is pumped in. Therefore, if it is to be implemented in a short period of time, a considerable number of pumps will be procured to inject a large amount of seawater. Also, as can be seen from Figure 11(d), the required head is high immediately after the spar-type float becomes upright (before it reaches the designed draft), so pumps with a considerable output must be prepared.

[0015] Thus, the conventional technology of using pumps to inject seawater into the main body of a spar-type floating structure requires the preparation of many large pumps. Moreover, the barges to mount the pumps and the power equipment to operate the pumps are also large, and a considerable number of workers are required to control the pumps. In other words, the costs of the pumps and barges (rent, fuel, etc.) and labor costs are high, and conventional water injection construction is quite costly.

[0016] In addition, each process shown in Figure 11 is carried out in principle in calm sea conditions, but of course there are times when the sea conditions become unstable. In that case, the work will have to be waited without being carried out, which will result in the rental fee for various machines and labor costs, and in this respect, the conventional water injection construction required a considerable cost.

[0017] On the other hand, the technology disclosed in Patent Document 2 does not require the preparation of many large-scale pumps, and therefore can significantly reduce construction costs compared to the technology of Patent Document 1 and the like. However, it is necessary to provide a connecting pipe and a water intake on the outside of the columnar body (float), and a special reinforcement structure may be required to avoid damage during horizontal towing. In addition, there may be a problem that the motion performance of the columnar body may deteriorate as a result of the fluid forces caused by waves and ocean currents acting on the connecting pipe during operation.

[0018] The object of the present invention is to solve the problems associated with the conventional technology, that is, to provide a spar-type floating body that can be erected more easily and at lower cost than conventional methods, and a method for erecting the spar-type floating body. [Means for solving the problem]

[0019] The present invention was made with a focus on the use of gravity to naturally inject seawater into the interior, and is based on a completely new idea.

[0020] The spar-type floating body of the present invention constitutes a floating offshore wind power generation facility, and includes a hollow columnar body with a bottom weight installed at the bottom, a water pipe, and an opening / closing means. The water pipe has a water intake port at its bottom side and a drainage port at its top side, and is disposed so as to be approximately parallel (including parallel) to the column axis of the columnar body and attached to the inner surface of the columnar body. The opening / closing means is a means for controlling the inflow of seawater into the water pipe, and when the opening / closing means is opened, the inflow of seawater from the water intake port is allowed, and when the opening / closing means is closed, the inflow of seawater from the water intake port is restricted. When the opening / closing means is closed and before seawater is poured into the inside, the columnar body is disposed so that the water pipe is on the seawater side, and floats on the sea surface in a "sideways state" inclined by the bottom weight so that the water intake port is located in the seawater. When the opening / closing means is opened in this sideways state, seawater flowing in from the water intake port is poured into the inside of the columnar body through the water intake port via the water pipe. As a result, the columnar body is erected while its bottom sinks into the sea and its axis tilts closer to vertical.

[0021] The spar-type floating body of the present invention may further include an upper weight attached to the columnar body. This upper weight is arranged so that the center of gravity of the columnar body overlaps with the water pipe when the columnar body is viewed in cross section. When the opening / closing means is closed and before seawater is poured into the columnar body, the columnar body is in a sideways state with the water pipe facing the seawater due to the effect of the upper weight being arranged. When seawater is poured into the columnar body and the drain outlet reaches sea level, the pouring of seawater stops, and the columnar body is in an "intermediate state" in which the upright position is interrupted. In the intermediate state, the columnar body is inclined so as to lean toward the upper weight.

[0022] The spar-type floating body of the present invention may be configured so that a part (or all) of the upper weight is detachable from the columnar body. In this case, when the upper weight is detached from the columnar body in the intermediate state, the columnar body is arranged so that the column axis is approximately vertical (including vertical).

[0023] The spar-type floating body of the present invention may further include an adjustment weight attached to the columnar body. In this case, the adjustment weight is attached to the columnar body in the intermediate state, and the columnar body is arranged so that the column axis is approximately vertical (including vertical).

[0024] The spar-type floating body of the present invention may further include a housing pipe for housing the water pipe. The housing pipe is attached to the columnar body. An opening is provided on the top side of the housing pipe, and an opening cover is provided on the opening for opening and closing the opening.

[0025] The method for erecting a spar-type float of the present invention is a method for erecting the spar-type float of the present invention in an upright state with seawater, and includes a pipe water injection process. In this pipe water injection process, the columnar body is laid on its side, and the opening and closing means is opened to allow seawater to flow in from the water intake and to inject seawater into the columnar body from the drainage port through the water pipe. By injecting seawater into the columnar body in the pipe water injection process, the columnar body is erected while the bottom of the columnar body is submerged in the sea and the column axis is tilted so as to approach vertical.

[0026] The method for erecting a spar-type float of the present invention can further include a transportation step and a weight removal step. In this transportation step, the spar-type float including the columnar body in a sideways state with the water-passing pipe facing the seawater by the upper weight is transported to a destination by sea. In the weight removal step, the upper weight is removed from the columnar body. In this case, in the pipe water injection step, seawater is injected into the columnar body of the spar-type float transported to the destination, and when the seawater is injected into the inside of the columnar body and the drain outlet reaches sea level, the injection of seawater stops, and the erection of the columnar body is interrupted and the columnar body is placed in an intermediate state. In the weight removal step, the upper weight is removed from the columnar body in the intermediate state, so that the columnar body is arranged so that the column axis is approximately vertical (including vertical). Effect of the Invention

[0027] The spar-type floating body and the method for erecting the spar-type floating body of the present invention have the following effects. (1) The spar-type floating structure can be erected without relying on large-scale pumps. As a result, the cost of large-scale pumps, pump barges, other equipment, and labor costs can be reduced, which means that the construction costs for water injection can be reduced. (2) Except for bad weather such as storms, water can be injected into the column body even when sea conditions are somewhat adverse. Therefore, there is no need to wait until the sea conditions become calm, and as a result, the number of days required for construction can be reduced. (3) There is no need to install any special equipment on the outside of the columnar body (float). Therefore, no special reinforcement structure is required for horizontal towing, and the problem of deterioration of the oscillation performance of the columnar body during operation can be avoided. [Brief description of the drawings]

[0028] [Figure 1] FIG. 1 is a longitudinal sectional view showing a schematic view of a spar-type floating body according to the present invention. [Diagram 2] FIG. 2A is a perspective view showing a columnar body provided with vertical ribs and horizontal ribs, and FIG. 2B is a cross-sectional view showing the columnar body provided with vertical ribs and horizontal ribs. [Diagram 3] 1A is a cross-sectional view showing a schematic view of the columnar body at the position where the water pipe is arranged, and FIG. 1B is a cross-sectional view showing a schematic view of the columnar body at the position where the upper weight is arranged. [Figure 4] FIG. 2 is a vertical cross-sectional view showing a schematic diagram of an upper weight consisting of a ballast container, a ballast discharge pipe, and a ballast valve. [Diagram 5] 1A is a cross-sectional view showing a schematic of an adjustment weight arranged opposite the upper weight, and FIG. 1B is a cross-sectional view showing a schematic of an adjustment weight arranged around the entire inner circumference of the columnar body excluding the upper weight. [Figure 6] FIG. 4 is a vertical cross-sectional view showing a schematic view of a housing pipe housing a water pipe therein. [Figure 7]FIG. 1A is a plan view showing a state in which the opening is closed by installing the opening / closing cover, and FIG. 1B is a plan view showing a state in which the opening is opened by removing the opening / closing cover. [Figure 8] FIG. 2 is a step diagram showing the procedure for erecting the spar-type floating body of the present invention. [Figure 9] FIG. 2 is a flow chart showing the main steps of the spar-type floating body erection method of the present invention. [Figure 10] FIG. 1 is a side view showing a schematic diagram of a spar-type offshore wind power generation facility. [Figure 11] FIG. 1 is a step diagram showing the conventional procedure for erecting a spar-type floating body. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0029] An example of an embodiment of the spar-type float and the method for erecting the spar-type float of the present invention will be described with reference to the drawings. The spar-type float of the present invention can be particularly suitably used as a component of a floating offshore wind power generation facility.

[0030] 1. Spar-type floating structure First, the spar-type float 100 of the present invention will be described in detail with reference to the drawings. The spar-type float erection method of the present invention is a method for erecting the spar-type float 100 of the present invention. Therefore, the spar-type float 100 of the present invention will be described first, and then the spar-type float erection method of the present invention will be described in detail.

[0031] Fig. 1 is a cross-sectional view showing a schematic diagram of a spar-type float 100 according to the present invention. As shown in this figure, the spar-type float 100 according to the present invention is composed of a columnar body 110, a water pipe 120, an opening / closing means 130, and a bottom weight 140, and may further be composed of an upper weight 150, an adjustment weight and a housing pipe, which will be described later. Below, each of the main elements constituting the spar-type float 100 will be explained.

[0032] (Columnar body) As shown in Fig. 1, the columnar body 110 is an elongated body whose axial dimension is greater than its cross-sectional dimension, and is hollow inside, i.e., its external shape is generally tubular. The columnar body 110 is a so-called open-bottomed tube, with one end (the lower end in the figure) closed and the other end (the upper end in the figure) open. For convenience, the central axis of the columnar body 110 as shown in Fig. 1 is referred to as the "column axis".

[0033] A bottom weight 140 is installed at the bottom of the columnar body 110. This bottom weight 140 is made of a material with a large unit weight, such as concrete or steel. The section in which the bottom weight 140 is installed has a larger weight per unit length in the column axial direction than other sections of the columnar body 110 (sections in which the bottom weight 140 is not installed). The columnar body 110 can be a cylinder with a circular cross section, or a prism with a polygonal cross section.

[0034] Further, the columnar body 110 may be provided with reinforcing vertical ribs 111 and horizontal ribs 112 on the inside as shown in FIG. 2. FIG. 2(a) is a perspective view showing the columnar body 110 provided with the vertical ribs 111 and horizontal ribs 112, and FIG. 2(b) is a cross-sectional view thereof. Note that FIG. 2(a) is partially cut away for convenience in order to show the inside. As shown in this figure, the vertical ribs 111 extending in the column axis direction are arranged at intervals in the circumferential direction, while the annular (ring-shaped) horizontal ribs 112 are arranged at intervals in the column axis direction. Of course, the material, shape, dimensions, and arrangement intervals of the vertical ribs 111 and horizontal ribs 112 may be determined based on design calculations.

[0035] (water pipe) The water pipe 120 is a hollow tubular member, and is disposed so as to be substantially parallel (including parallel) to the axis of the column, and is attached to the inner surface of the columnar body 110. A water inlet 120E is provided at one end (the lower end in FIG. 1) of the water pipe 120, and a drainage outlet 120D is provided at the other end (the upper end in FIG. 1). However, the water inlet 120E is located on the bottom side (i.e., the bottom weight 140 side), and the drainage outlet 120D is located on the top side. This water inlet 120E is for taking in seawater, and therefore the columnar body 110 is opened at the position where the water inlet 120E is provided. Seawater flowing in from the water inlet 120E flows through the water pipe 120 and is discharged into the columnar body 110 from the drainage outlet 120D.

[0036] When the vertical ribs 111 are provided inside the columnar body 110, the water pipes 120 can be attached in the "gaps" between the vertical ribs 111 as shown in FIG. 2. Naturally, the water pipes 120 have an outer diameter smaller than the interval (e.g., 700 mm) between the vertical ribs 111. In this case, the vertical ribs 111 can be used as a support structure for the water pipes 120, so that the water pipes 120 can be easily attached and the support structure can be simplified. In addition, only one water pipe 120 can be attached to the columnar body 110, or two or more water pipes 120 can be attached. By providing two or more water pipes 120, the inflow speed of seawater can be increased or the main water pipe 120 can be switched to another water pipe 120 when an unexpected event occurs. Therefore, when two or more water pipes 120 are provided, it is preferable to install them in close proximity to each other. For example, in FIG. 2(b), three water pipes 120 are arranged in adjacent gaps.

[0037] (Opening and closing means) The opening and closing means 130 controls the inflow of seawater into the water pipe 120, and may be, for example, a valve. When the opening and closing means 130 is opened (uncapped), the inflow of seawater from the water intake 120E is permitted, and when the opening and closing means 130 is closed (capped), the inflow of seawater from the water intake 120E is restricted. It is preferable to adopt an opening and closing means 130 that can be remotely operated for opening and closing. For example, the opening and closing of the opening and closing means 130 is performed by an operator located away from the spar-type float 100, such as on land or on a ship, or on a working platform installed outside the spar-type float 100.

[0038] The opening / closing means 130 may be provided in only one location, or in two or more locations. By providing two or more opening / closing means 130, it is possible to prepare for unexpected situations such as operational malfunctions. When providing opening / closing means 130 in two or more locations, it is preferable to arrange them in a line along the axis of the water pipe 120 (hereinafter referred to as the "pipe axis").

[0039] (Upper weight) The upper weight 150 is arranged so that the water pipe 120 faces the seawater side (i.e., the lower side) as shown in Fig. 3(a) when the spar-type floating body 100 is placed on its side and floated in seawater. Therefore, the upper weight 150 is arranged so that the position of its center of gravity overlaps the position of the water pipe 120 when the columnar body 110 is viewed in cross section. More specifically, if the cross section (e.g., circular) of the columnar body 110 is likened to a clock, when the water pipe 120 is at the "6 o'clock" position, the upper weight 150 is arranged so that the position of its center of gravity is also at the "6 o'clock" position. For example, the upper weight 150 shown in Fig. 3(b) is arranged in a part of the cross section of the columnar body 110 and is arranged so as to be on the pipe axis of the water pipe 120. Of course, various arrangements can be adopted, such as arranging the two upper weights 150 so that they are symmetrical with respect to the water pipe 120, so long as the center of gravity can be aligned with the water pipe 120. For convenience, the function of placing the water pipe 120 on the seawater side by overlapping the center of gravity of the upper weight 150 with the water pipe 120 is referred to as the "eccentric function" here.

[0040] On the other hand, the upper weight 150 can be placed at any position in the column axis direction of the columnar body 110. However, in order to lay the spar-type floating body 100 (particularly the columnar body 110) on its side, it is preferable that the distance between the bottom weight 140 and the upper weight 150 is as large as possible. For example, in FIG. 1, the upper weight 150 is placed closer to the top than the water pipe 120.

[0041] Also, the upper weight 150 can be attached so that a part (or all) of the upper weight 150 can be removed from the columnar body 110. When removing a part (or all) of the upper weight 150, it is preferable to configure it so that it can be remotely operated by an operator who is away from the spar-type floating body 100, such as on land or on a ship, as with the opening / closing means 130. For example, FIG. 4 shows the upper weight 150 consisting of a ballast container 151, a ballast discharge pipe 152, and a ballast valve 153. In this example, the ballast valve 153 is opened (uncapped) by remote control to discharge ballast BL such as seawater contained in the ballast container 151 through the ballast discharge pipe 152, that is, a part (in this case, ballast BL) of the upper weight 150 is removed. In this way, by removing a part (or all) of the upper weight 150 from the columnar body 110, the eccentric function of the upper weight 150 is eliminated.

[0042] Instead of the ballast discharge pipe 152 and the ballast valve 153 shown in Fig. 4, a remotely operable "opening door" may be provided in the ballast storage body 151. That is, the ballast BL stored in the ballast storage body 151 is discharged by opening (opening) the opening door by remote control by an operator. In this case, in addition to seawater, concrete or steel weights may be used as the ballast BL.

[0043] In order to eliminate the eccentricity function caused by the upper weight 150, instead of removing a part (or the whole) of the upper weight 150, an adjustment weight 160 shown in Fig. 5 can be used. By additionally arranging this adjustment weight 160, the eccentricity function caused by the upper weight 150 is eliminated. For example, in Fig. 5(a), the adjustment weight 160 is arranged at a position facing the upper weight 150 (above in the figure), and in Fig. 5(b), the adjustment weight 160 is arranged on the entire inner circumference of the columnar body 110 (excluding the upper weight 150), and in both cases, the position of the center of gravity in the cross section of the columnar body 110 is approximately the center, that is, the eccentricity function caused by the upper weight 150 is eliminated.

[0044] When additionally arranging the adjustment weight 160, it is also preferable to adopt a configuration that allows remote operation by an operator. For example, a compartment that holds seawater may be provided, and the adjustment weight 160 may be additionally arranged by injecting seawater into the compartment by remote operation. Alternatively, the adjustment weight 160 may be arranged in advance at a position where the eccentric function of the upper weight 150 is ensured, and the adjustment weight 160 may be moved by remote operation to a position where the eccentric function is eliminated.

[0045] (Containing tube) The water pipe 120 is in contact with seawater at the water intake 120E and communicates with the inside of the columnar body 110 at the drainage outlet 120D, and is used when the spar-type floating body 100 is erected. On the other hand, when the spar-type floating body 100 is in operation, that is, when the columnar body 110 is in an upright state, it is considered that the drainage outlet 120D is located below the water surface as shown in FIG. 8(e) described later. In that case, seawater will be further injected into the columnar body 110, and as a result, the columnar body 110 may sink beyond the designed draft. Therefore, when the spar-type floating body 100 is in operation, it is necessary to prevent seawater from being injected through the drainage outlet 120D.

[0046] The encasement pipe 170 is attached to the inner surface of the columnar body 110 and has a function of preventing seawater from being poured in through the drainage port 120D when the spar-type floating body 100 is in operation. Specifically, as shown in FIG. 6, the encasement pipe 170 has a double-pipe structure in which the water passage pipe 120 is housed inside the encasement pipe 170. However, the encasement pipe 170 has a watertight structure that prevents seawater from entering from the outside. This makes it possible to prevent seawater from flowing into the water passage pipe 120 through the drainage port 120D when the spar-type floating body 100 is in operation. In addition, when the vertical rib 111 is provided on the inner side of the columnar body 110 as shown in FIG. 2, the encasement pipe 170 can also be formed by using the adjacent vertical ribs 111 and the vertical ribs 111. In other words, the "gap" is sealed from the inside by attaching a plate-shaped material to the two adjacent vertical ribs 111, and the bottom and top surfaces are further sealed with plate-shaped materials to form the encasement pipe 170 with a watertight structure.

[0047] On the other hand, when the spar type floating body 100 is erected, it is necessary to discharge the seawater that has flowed into the water pipe 120 from the water intake 120E into the columnar body 110 through the drainage port 120D. For this purpose, an opening 172 is provided on the top side of the housing pipe 170 as shown in Fig. 7, and an opening / closing lid 171 is further provided to seal the opening 172 with water. When the spar type floating body 100 is erected, the opening 172 is opened by removing the opening / closing lid 171 as shown in Fig. 7(b) to connect the drainage port 120D to the inside of the columnar body 110, and when the spar type floating body 100 is in operation, the opening 172 is closed by installing the opening / closing lid 171 as shown in Fig. 7(a) to make the inside of the housing pipe 170 watertight.

[0048] (Example of use) Hereinafter, the procedure for erecting the spar-type floating body 100 of the present invention will be described with reference to FIG. 8. FIG. 8 is a step diagram showing the procedure for erecting the spar-type floating body 100 of the present invention. As shown in this figure, the spar-type floating body 100 in a sideways state is first towed to a preselected calm area. However, at this time, the columnar body 110 is in a hollow state in which seawater has not yet been poured into it, and the opening / closing means 130 is in a closed (plugged) state, that is, seawater does not flow in from the water intake 120E. The columnar body 110 with the opening / closing means 130 closed and the inside in a hollow state is inclined so that the water intake 120E is located in the seawater due to the effect of the bottom weight 140, and further, is arranged so that the water pipe 120 is on the seawater side (i.e., the lower side) due to the effect of the eccentric function of the upper weight 150, as shown in FIG. 8(a). For the sake of convenience, the state shown in FIG. 8(a) will be referred to as the "laterally laid state" here.

[0049] When the spar-type floating body 100 with the columnar body 110 in a sideways state is towed to a calm area, the opening / closing means 130 is opened (uncapped). In addition, in the case where the housing pipe 170 is provided, the opening / closing cover 171 is removed to open the opening 172. This allows seawater to naturally flow in from the water intake 120E, and the seawater that has flowed through the water passage pipe 120 is poured into the columnar body 110 from the water outlet 120D. When seawater accumulates inside due to the water injection, the columnar body 110 rotates (inclines) due to its own weight so that the bottom of the columnar body 110 sinks in the sea and the column axis approaches vertical (counterclockwise in the figure), as shown in FIG. 8(b).

[0050] As the seawater injection progresses and the outlet 120D reaches sea level as shown in FIG. 8(c), the inflow of seawater from the intake 120E stops. Accordingly, the rotation (standing) of the columnar body 110 also stops, and the columnar body 110 is inclined toward the upper weight 150 (the right side in the figure) (hereinafter referred to as the "intermediate state"). When the columnar body 110 is in the intermediate state, a part (or the whole) of the upper weight 150 is removed. As a result, the columnar body 110 is in a state in which the column axis is approximately vertical (including vertical) (i.e., an upright state) as shown in FIG. 8(d) due to the effect of eliminating the eccentric function of the upper weight 150. Note that instead of removing the upper weight 150, an adjustment weight 160 can be additionally placed.

[0051] When the columnar body 110 is brought into the upright state, the opening / closing means 130 is closed (plugged), and ballast such as crushed stone and seawater is poured into the columnar body 110 until the designed draft is reached. At this time, ballast can be poured through the opening at the upper end of the columnar body 110. In the case where the housing pipe 170 is provided, the opening 172 is sealed off by installing the opening / closing lid 171 before pouring in the ballast. When the columnar body 110 in the upright state is submerged until the designed draft is reached, the windmill unit is attached to the columnar body 110 to construct the spar-type floating body 100, as shown in FIG. 8(e).

[0052] 2.How to erect a spar-type floating structure Next, the method for erecting a spar-type float of the present invention will be described in detail with reference to Fig. 9. The method for erecting a spar-type float of the present invention is a method for erecting the spar-type float 100 described so far, and therefore, we will avoid any overlapping description with the description of the spar-type float 100, and will only describe the contents unique to the method for erecting a spar-type float of the present invention. In other words, the contents not described here are the same as those described in "1. Spar-type float".

[0053] Fig. 9 is a flow diagram showing the main steps of the spar-type float erection method of the present invention. As shown in this figure, first, the spar-type float 100 is manufactured in a dry dock or the like (Step 201 in Fig. 9). Then, during a period when the tide level, tidal current, and other environmental conditions are favorable, the spar-type float 100 with the columnar body 110 laid down is towed by a tugboat or the like to a calm area selected in advance (Step 202 in Fig. 9), and the spar-type float 100 is temporarily moored there (Step 203 in Fig. 9).

[0054] When the spar-type floating body 100 is temporarily moored in a calm area, the opening / closing means 130 is opened (opened). This allows seawater to naturally flow in from the water intake 120E, and the seawater that has flowed through the water passage pipe 120 is then poured into the columnar body 110 from the water outlet 120D (Step 204 in FIG. 9). When the seawater injection progresses and the water outlet 120D reaches sea level, the inflow of seawater from the water intake 120E stops, and the columnar body 110 is placed in the intermediate state (Step 205 in FIG. 9). When the columnar body 110 is placed in the intermediate state, a part (or the whole) of the upper weight 150 is removed, and the columnar body 110 is placed in the upright state (Step 206 in FIG. 9). Once the columnar body 110 is in the upright position, the opening and closing means 130 is closed (plugged) (Step 207 in Figure 9), and ballast such as crushed stone and seawater is poured into the columnar body 110 until the designed draft is reached (Step 208 in Figure 9).

[0055] When the spar-type float 100 reaches the planned height, the wind turbine unit is installed above the spar-type float 100 (Step 209 in Fig. 9), and a completed body consisting of the wind turbine unit and the spar-type float 100 is constructed, and then temporarily moored in a calm area (Step 210 in Fig. 9). Then, aiming for a time when the environment is favorable in terms of tides and currents, the completed body is towed by a tugboat to the WF waters (Step 211 in Fig. 9), where the completed spar-type float 100 is permanently moored (Step 212 in Fig. 9), and a submarine cable is installed to the completed body (Step 213 in Fig. 9). [Industrial Applicability]

[0056] The spar-type float and the method for erecting the spar-type float of the present invention are particularly suitable for use in floating offshore wind power generation in sea areas 50 m or deeper. Since the present invention allows floating offshore wind power generation facilities to be installed easily and at low cost, it is expected to provide a more positive motivation for offshore wind power generation, and considering the need to provide a stable supply of energy while reducing greenhouse gas emissions, the present invention can be said to be an invention that can be expected to not only be used industrially but also to make a significant contribution to society. [Explanation of symbols]

[0057] 100 Spar-type floating body of the present invention 110 (Spar-type floating body) column-shaped body 111 (Columnar body) Longitudinal rib 112 (Columnar Body) Transverse Rib 120 (Spar-type floating body) water pipe 120E (Water Pipe) Intake 120D (Water Pipe) Outlet 130 (Spar-type floating body) opening and closing means 140 (of a spar-type float) bottom weight 150 (Spar-type float) upper weight 151 (Upper weight) ballast housing 152 (Upper weight) ballast discharge pipe 153 (Upper weight) ballast valve 160 (Spar-type float) Adjustment weight 170 (Spar-type float) containment tube 171 (Containment tube) Opening and Closing Cover 172 (Containment tube) opening BL Ballast

Claims

1. A spar-type floating body constituting a floating offshore wind power generation facility, A hollow columnar body having a bottom weight attached to the bottom; a water pipe disposed parallel or approximately parallel to the column axis of the columnar body and attached to the inner surface of the columnar body; and an opening / closing means for controlling the inflow of seawater into the water pipe, A water intake port is provided at the bottom side of the water pipe, and a water outlet port is provided at the top side of the water pipe; When the opening / closing means is opened, seawater can flow in through the water intake, When the opening and closing means is closed, the inflow of seawater from the water intake is restricted, When the opening / closing means is closed and before seawater is poured into the interior, the columnar body is arranged so that the water pipe faces the seawater side, and floats on the sea surface in a tilted state with the bottom weight so that the water intake is located in the seawater, When the opening / closing means is opened in the laid-down state, seawater flowing in from the water intake is poured into the inside of the columnar body from the drainage port through the water pipe, and the columnar body is raised up while the bottom of the columnar body is submerged in the sea and the column axis is tilted to approach vertical. A spar-type floating structure characterized by:

2. An upper weight is disposed on the axis of the water pipe in a part of the circumferential direction of the columnar body and attached to the columnar body, the upper weight is disposed so that a center of gravity of the upper weight overlaps with the water pipe when the columnar body is viewed in cross section, When the opening / closing means is closed and before seawater is poured into the inside, the columnar body is placed in the sideways position by the upper weight with the water pipe facing the seawater, When seawater is poured into the inside of the columnar body and the outlet port reaches sea level, the pouring of seawater is stopped, so that the columnar body is in an intermediate state where the erection is interrupted, The columnar body in the intermediate state is inclined toward the upper weight.

2. The spar-type floating body according to claim 1.

3. A part or the whole of the upper weight is removable from the columnar body; When the upper weight is removed from the columnar body in the intermediate state, the columnar body is arranged so that the column axis is vertical or approximately vertical.

3. The spar-type floating body according to claim 2.

4. Further comprising an adjustment weight attached to the columnar body; When the adjustment weight is attached to the columnar body in the intermediate state, the columnar body is arranged so that the column axis is vertical or approximately vertical.

3. The spar-type floating body according to claim 2.

5. The water supply pipe further includes a housing pipe attached to the columnar body and housing the water supply pipe, An opening is provided on the top side of the housing tube, The opening is provided with an opening / closing cover that opens and closes the opening.

2. The spar-type floating body according to claim 1.

6. A method for erecting the spar-type floating body according to claim 1 so as to be in an upright state in seawater, comprising the steps of: and a pipe water injection process for opening the opening / closing means after placing the columnar body in the sideways position, allowing seawater to flow in from the water intake port, and injecting seawater into the columnar body from the water outlet through the water pipe, In the pipe water injection process, seawater is injected into the columnar body, so that the bottom of the columnar body is submerged in the sea and the column axis is tilted so as to approach vertical, thereby causing the columnar body to stand upright. A method for erecting a spar-type floating structure.

7. The spar-type floating body further has an upper weight, the upper weight is disposed on an axis of the water pipe at a portion of a circumferential direction of the columnar body and is attached to the columnar body, and is detachable from the columnar body; a transporting step of transporting the spar-type floating body including the columnar body in the sideways-down state in which the water-passing pipe faces the seawater by the upper weight to a destination by sea; and a weight removing step of removing the upper weight from the columnar body. In the pipe water injection process, seawater is injected into the columnar body of the spar-type floating body transported to the destination, and when the seawater is injected into the inside of the columnar body and the outlet reaches sea level, the injection of seawater is stopped to interrupt the erection of the columnar body, thereby bringing the columnar body into an intermediate state; In the weight removing step, the upper weight is removed from the columnar body in the intermediate state, thereby disposing the columnar body so that the column axis is vertical or approximately vertical.

7. A method for erecting a spar-type floating structure according to claim 6.

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