Spar-type floating body, and method for erecting a spar-type floating body.

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 floating body capable of naturally injecting seawater into the interior by using gravity, and a method for erecting the spar-type floating body. [[Background Art]]

[0002] Although power consumption in Japan once decreased due to the impact of the 2008 global financial crisis, it has increased continuously since 1973 when the oil crisis occurred, and particularly expanded to 2.6 times between the 1973 fiscal year and the 2007 fiscal year. The background to this includes the spread of so-called household electrical appliances such as air conditioners and electric carpets along with the improvement of living standards, or the spread of OA (Office Automation) equipment and communication equipment along with the increase in office buildings.

[0003] Hitherto, power generation using so-called fossil fuels such as petroleum, coal, and natural gas has mainly supported such a huge amount of power demand. However, in recent years, the problem of depletion of fossil fuels and environmental problems associated with global warming have attracted attention, and power generation methods have gradually changed in response to this. As a result, according to statistics from the Federation of Electric Power Companies of Japan, while annual power generation from petroleum accounted for approximately 46% of the total around 1980, this proportion decreased to 9% by 2010. What has increased instead is nuclear power generation, which accounts for just over 25% of the total (as of 2010). Compared with conventional power generation methods, nuclear power generation has a remarkable greenhouse gas reduction effect, and can provide electric power at low cost, so it has greatly contributed to the power demand of Japan.

[0004] Furthermore, renewable energy power generation methods are being adopted because they can reduce greenhouse gas emissions, and by 2020, they accounted for approximately 12% of the total annual power generation (Federation of Electric Power Companies). These renewable energy sources include solar, wind, geothermal, small-scale hydropower, and woody biomass, which are literally renewable energy sources. Because they reduce greenhouse gas emissions and can be produced domestically, they are expected to be promising low-carbon energy sources.

[0005] Among renewable energy sources, wind power generation has the advantage of high efficiency in converting electrical energy. Generally, the conversion efficiency of solar power generation is said to be about 20%, wood biomass power generation is about 20%, and geothermal power generation is 10-20%, while wind power generation is said to be 20-40%, meaning it can convert energy into electricity more efficiently than other power generation methods. In addition, unlike solar power generation, wind power generation can generate electricity day and night, which is another advantage of wind power generation. 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 generation mix by 2030.

[0006] Wind power generation is broadly classified into onshore wind power generation and offshore wind power generation depending on the installation location. Onshore wind power generation has the advantage of being easier to install and therefore less expensive than offshore wind power generation. Offshore wind power generation, on the other hand, does not have the noise problems associated with onshore wind power generation, and the risk of damage from toppling etc. is avoided, and above all, it has the advantage of being able to obtain a large amount of wind power stably compared to onshore. Japan, which has the world's sixth-largest exclusive economic zone, is a suitable location for offshore wind power generation and is considered to have the potential to become a promising source of renewable energy in the future.

[0007] Furthermore, different types of offshore wind power generation are employed depending on the installation location. Fixed-bottom offshore wind power generation is suitable for sea areas shallower than 50m, while floating offshore wind power generation is suitable for sea areas deeper than 50m. Floating offshore wind power generation utilizes a floating structure that floats on seawater. The power generation mechanism is installed on the floating structure, which is connected by mooring lines, and this mechanism generates electricity. Examples of floating structure types include barge type, semi-submersible type, spar type, and tension-leg platform (TLP). Of these, the spar type offshore wind power generation facility is considered advantageous in terms of floating structure manufacturing costs because the structure of the spar floating structure is not very complex, which reduces the effort required for manufacturing, and because the spar floating structure is lightweight, the material costs can also be kept down.

[0008] Figure 10 is a schematic side view of a spar-type offshore wind power plant. As shown in this figure, a spar-type offshore wind power plant consists of a spar-type floating body that floats in the sea, and a tower, rotor, nacelle, etc. (hereinafter collectively referred to as the "wind turbine section") installed on top of it. The tower is a structure that supports the rotor and nacelle, and the spar-type floating body functions as the base of the tower. The rotor, consisting 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 then transmitted to land via power cables (dynamic cables and submarine cables). The spar-type floating body is generally moored by the weight of mooring cables arranged in a catenary shape.

[0009] The main body of the spar-type floating structure is a long, slender body with a large axial dimension (hereinafter referred to as "column axis") compared to its cross-sectional dimensions, and has a hollow, tubular shape inside. As shown in Figure 10, the spar-type floating structure is in a state where its column axis is approximately vertical (including vertical) during operation (hereinafter referred to as the "upright state"). Normally, these spar-type floating structures are manufactured on land, such as in dry docks, and need to be transported by sea to the operational area (wind farm area: WF area). Although there are examples of transporting spar-type floating structures in the upright state in some areas such as Northern Europe, in Japan, where the water depth around the land is shallow, spar-type floating structures are transported with the column axis approximately horizontal.

[0010] Therefore, in order to make it operational, the spar-type floating structure needs to be rotated from a nearly horizontal position to an upright position (hereinafter referred to as "erecting"). However, since considerable wind and wave forces are expected in the waterfall area, erecting the spar-type floating structure is not easy, and it is generally done in a pre-selected calm area of ​​the sea. The wind turbine section is manufactured separately from the spar-type floating structure, transported to a calm area, and installed on the erected spar-type floating structure using a crane ship or similar equipment. The structure, which is largely completed as an offshore wind power generation facility, is then transported to the waterfall area in an operational state (i.e., with the spar-type floating structure in an upright position).

[0011] Conventionally, when erecting a spar-type floating structure, as shown in Patent Document 1, a high-power pump was used to inject ballast water (e.g., seawater) into the main body of the spar-type floating structure, and the weight of the ballast water accumulating inside was used to erect it. Furthermore, as shown in Patent Document 2, a technology has been proposed for easily and inexpensively erecting a spar-type floating structure without relying on a high-power pump. [Prior art documents] [Patent Documents]

[0012] [Patent Document 1] Japanese Patent Publication No. 2012-201217 [Patent Document 2] Japanese Patent Publication No. 2022-014509 [Overview of the Initiative] [Problems that the invention aims to solve]

[0013] Figure 11 is a step diagram showing the conventional procedure for erecting a spar-type floating structure. The conventional procedure for erecting a spar-type floating structure will be explained with reference to this figure. First, as shown in Figure 11(a), the spar-type floating structure, which has been manufactured in a dry dock or the like, is transported by tugboat to a pre-selected calm area of ​​the sea. Once the spar-type floating structure has been transported to the target calm area, seawater is injected into the main body using a pump, as shown in Figure 11(b). Since a weight made of concrete or the like is attached to the bottom of the spar-type floating structure, the bottom of the spar-type floating structure is slightly submerged and sloped even before seawater injection begins. Therefore, as seawater injection progresses, the angle of inclination (the angle of intersection between the horizontal plane and the axis of the spar-type floating structure's column) increases, as shown in Figure 11(c), and finally the spar-type floating structure becomes upright, as shown in Figure 11(d). Then, from the state shown in Figure 11(d), seawater injection is further continued to sink the spar-type floating structure until the planned draft is achieved.

[0014] The spar-type floating structures that make up floating offshore wind power generation facilities have a considerable diameter and axial length, and therefore, a considerable amount of seawater must be injected to sink the spar-type floating structures to the planned draft. For this reason, if the project is to be carried out in a short period of time, a considerable number of pumps will need to be procured to inject large amounts of seawater. Also, as can be seen from Figure 11(d), the required head is high immediately after the spar-type floating structures become upright (before reaching the planned draft), so pumps with a considerable output must be prepared.

[0015] Thus, conventional techniques for injecting seawater into the main body of a spar-type floating structure using pumps require a large number of large pumps. Moreover, the barges that house the pumps and the power equipment for operating the pumps are also large, and a considerable number of workers are needed to control the pumps. In other words, the costs associated with the pumps and barges (rent, fuel, etc.) and labor costs are substantial, making conventional water injection construction quite expensive.

[0016] Furthermore, while each step shown in Figure 11 is generally carried out under calm sea conditions, unstable sea conditions can naturally occur. In such cases, work must be suspended, resulting in increased costs for machinery and labor. In this respect, conventional water injection construction methods have incurred considerable costs.

[0017] On the other hand, the technology disclosed in Patent Document 2 does not require the provision of numerous large-scale pumps, thus significantly reducing construction costs compared to technologies such as those described in Patent Document 1. However, it is necessary to provide connecting pipes and water intakes on the outside of the columnar body (floating body), and it is conceivable that a special reinforcing structure would be required to avoid damage during horizontal towing. Furthermore, it is conceivable that the vibration performance of the columnar body may deteriorate as a result of the fluid forces from waves and ocean currents acting on the connecting pipes during operation.

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

[0019] This invention focuses on the idea of ​​using gravity to naturally fill the interior with seawater, and is based on a completely new concept.

[0020] The spar-type floating structure of the present invention constitutes a floating offshore wind power generation facility and comprises a hollow columnar body with a bottom weight installed at its base, a water passage pipe, and an opening / closing mechanism. The water passage pipe has a water intake on its bottom side and a drain outlet on its top side, and is positioned 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 mechanism is a means of controlling the inflow of seawater into the water passage pipe; when the opening / closing mechanism is opened, seawater can flow in from the water intake, and when the opening / closing mechanism is closed, the inflow of seawater from the water intake is restricted. When the opening / closing mechanism is closed and seawater has not yet been injected into the interior, the columnar body, positioned so that the water passage pipe faces the seawater side, floats on the sea surface in a "lying-down state" tilted by the bottom weight so that the water intake is located in the seawater. When the opening / closing mechanism is opened in this lying-down state, seawater that has flowed in from the water intake is injected into the interior of the columnar body through the water passage pipe and the drain outlet. As a result, the columnar body is erected while tilting so that its base sinks into the sea and its axis approaches vertical.

[0021] The spar-type float of the present invention may also be further equipped with an upper weight attached to the columnar body. This upper weight is positioned such that, when the columnar body is viewed in cross-section, its center of gravity coincides with the water passage pipe. When the opening and closing mechanism is closed and seawater is not injected into the interior, the columnar body is in a lying position with the water passage pipe facing the seawater due to the effect of the upper weight. When seawater is injected into the interior of the columnar body and the drain outlet reaches sea level, the injection of seawater stops, and the columnar body is placed in an "intermediate state" where its uprighting is interrupted. The columnar body in this intermediate state is tilted toward the upper weight.

[0022] The spar-type floating body of the present invention may also be configured such that part (or all) of the upper weight can be removed from the columnar body. In this case, when the upper weight is removed from the columnar body which is in an intermediate state, the columnar body is positioned so that the column axis is approximately vertical (including vertical).

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

[0024] The spar-type floating body of the present invention may further comprise an accommodating pipe that accommodates a water flow pipe. The accommodating pipe is attached to the columnar body. An opening is provided on the top side of the accommodating pipe, and an opening / closing lid that opens and closes the opening is provided at the opening.

[0025] The method for erecting a spar-type floating body of the present invention is a method for erecting the spar-type floating body of the present invention in an upright state in seawater, and the method comprises an in-pipe water injection step. In this in-pipe water injection step, after the columnar body is placed in a horizontally laid state, the opening / closing means is opened to allow seawater to flow in from the water intake, and seawater is injected into the columnar body from the drainage port through the water flow pipe. By injecting seawater into the columnar body in the in-pipe water injection step, the columnar body is erected while tilting such that the bottom of the columnar body sinks into the sea and the column axis approaches vertically.

[0026] The method for erecting a spar-type floating body of the present invention may further comprise a transportation step and a weight removing step. In this transportation step, the spar-type floating body including the columnar body that is placed in a horizontally laid state with the water flow pipe facing the seawater side by an upper weight is transported by sea to a destination. In the weight removing step, the upper weight is removed from the columnar body. In this case, in the in-pipe water injection step, seawater is injected into the columnar body of the spar-type floating body transported to the destination; when seawater is injected into the interior of the columnar body and the drainage port reaches the sea level, the injection of seawater is stopped, and accordingly, the columnar body is brought into an intermediate state where the erection is suspended. In the weight removing step, by removing the upper weight from the columnar body in the intermediate state, the columnar body is arranged such that the column axis is substantially vertical (including vertical). [Effects of the Invention]

[0027] The spar-type floating body and the method for erecting the spar-type floating body according to the present invention have the following advantages. (1) The spar-type floating structure can be erected without relying on large-scale pumps. As a result, costs associated with large-scale pumps, as well as pump barges, other equipment, and labor costs can be reduced, thus lowering the construction costs for water injection. (2) Except in the case of severe weather such as storms, water can be injected into the columnar structure even if the sea conditions are somewhat unfavorable, so there is no need to wait until the sea conditions become calm, and as a result the number of construction days can be shortened. (3) There is no need to install any special equipment on the outside of the columnar body (floating body). Therefore, there is no need for a special reinforcing structure for horizontal towing, and problems such as deterioration of the sway performance of the columnar body during operation can be avoided. [Brief explanation of the drawing]

[0028] [Figure 1] A schematic longitudinal cross-sectional view showing the spar-type floating body of the present invention. [Figure 2] (a) is a perspective view showing a columnar body with longitudinal and transverse ribs, and (b) is a cross-sectional view showing a columnar body with longitudinal and transverse ribs. [Figure 3] (a) is a schematic cross-sectional view showing the columnar body at the location where the water pipe is installed, and (b) is a schematic cross-sectional view showing the columnar body at the location where the upper weight is installed. [Figure 4] A schematic longitudinal cross-sectional view showing the upper weight, which consists of a ballast container, ballast discharge pipe, and ballast valve. [Figure 5] (a) is a schematic cross-sectional view showing the adjustment weights positioned opposite the upper weight, and (b) is a schematic cross-sectional view showing the adjustment weights positioned around the entire inner circumference of the columnar body excluding the upper weight. [Figure 6] A schematic longitudinal cross-sectional view showing a housing pipe containing a water pipe inside. [Figure 7](a) is a schematic plan view showing the opening sealed by installing an opening / closing cover, and (b) is a schematic plan view showing the opening opened by removing the opening / closing cover. [Figure 8] A step diagram showing the procedure for erecting the spar-type floating body of the present invention. [Figure 9] A flowchart showing the main steps of the spar-type floating body erection method of the present invention. [Figure 10] A schematic side view illustrating a spar-type offshore wind power facility. [Figure 11] A step-by-step diagram showing the conventional procedure used to erect a spar-type floating structure. [Modes for carrying out the invention]

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

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

[0031] Figure 1 is a schematic cross-sectional view of the spar-type floating body 100 of the present invention. As shown in this figure, the spar-type floating body 100 of the present invention is composed of a columnar body 110, a water passage pipe 120, an opening / closing mechanism 130, and a bottom weight 140, and may also be composed of an upper weight 150, an adjustment weight described later, a housing pipe, etc. The main elements constituting the spar-type floating body 100 will be described below.

[0032] (Columnar body) As shown in Figure 1, the columnar body 110 is an elongated body in which the axial dimension is significantly larger than the cross-sectional dimension, and the interior is hollow, meaning that the outer shape is generally tubular. Furthermore, the columnar body 110 is a so-called bottomed open pipe, 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 will be referred to as the "columnar axis" as shown in Figure 1.

[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 high unit weight, such as concrete or steel. The section in which the bottom weight 140 is installed has a greater weight per unit length in the column axis direction compared to other sections of the columnar body 110 (sections in which the bottom weight 140 is not installed). The columnar body 110 can be cylindrical with a circular cross-section, or it can be a rectangular prism with a polygonal cross-section.

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

[0035] (water pipe) The water passage pipe 120 is a hollow tubular member that is positioned approximately parallel (including parallel) to the column axis and attached to the inner surface of the columnar body 110. An intake port 120E is provided at one end of the water passage pipe 120 (the lower end in Figure 1), and a drain port 120D is provided at the other end (the upper end in Figure 1). However, the intake port 120E is on the bottom side (i.e., the bottom weight 140 side), and the drain port 120D is on the top side. This intake port 120E is for taking in seawater, and therefore the columnar body 110 is open at the position where the intake port 120E is provided. The seawater that flows in from the intake port 120E passes through the water passage pipe 120 and is discharged into the columnar body 110 from the drain port 120D.

[0036] When vertical ribs 111 are provided inside the columnar body 110, a water pipe 120 can be installed in the "gap" between the vertical ribs 111, as shown in Figure 2. Naturally, a water pipe 120 with an outer diameter smaller than the spacing between the vertical ribs 111 (for example, 700 mm) will be used. In this case, the vertical ribs 111 can be used as a support structure for the water pipe 120, which has the advantage of making it easy to install the water pipe 120 and simplifying the support structure. In addition, only one water pipe 120 can be installed on the columnar body 110, or two or more water pipes 120 can be installed. By providing two or more water pipes 120, it is possible to increase the inflow velocity of seawater or to switch to another water pipe 120 in the event of an unforeseen problem with the main water pipe 120. For this reason, when providing two or more water pipes 120, it is best to install them in close proximity to each other. For example, in Figure 2(b), three water pipes 120 are arranged in adjacent gaps.

[0037] (Opening and closing mechanism) The opening / closing mechanism 130 controls the inflow of seawater into the water pipe 120, and can utilize a valve, for example. Opening (opening) the opening / closing mechanism 130 allows seawater to flow in from the intake port 120E, and closing (closing) the opening / closing mechanism 130 restricts the inflow of seawater from the intake port 120E. It is preferable to use an opening / closing mechanism 130 that can be remotely operated. For example, an operator located away from the spar-type floating body 100, such as on land, on a ship, or on a working platform located outside the spar-type floating body 100, can operate the opening and closing mechanism 130.

[0038] The opening / closing mechanism 130 can be provided in only one location, or in two or more locations. Providing two or more opening / closing mechanisms 130 allows for preparation for unforeseen circumstances such as operational malfunctions. When providing two or more opening / closing mechanisms 130, it is preferable to arrange them so that they are aligned along the axis of the water pipe 120 (hereinafter referred to as the "pipe axis").

[0039] (Upper weight) The upper weight 150 is positioned so that when the spar-type float 100 is laid on its side and floated in seawater, the water pipe 120 is on the seawater side (i.e., the bottom side), as shown in Figure 3(a). Therefore, the upper weight 150 is positioned so that when the columnar body 110 is viewed in cross-section, its center of gravity coincides with the position of the water pipe 120. More specifically, if the cross-section of the columnar body 110 (for example, circular) is likened to a clock, the upper weight 150 is positioned so that when the water pipe 120 is at the "6 o'clock" position, its center of gravity is also at the "6 o'clock" position. For example, the upper weight 150 shown in Figure 3(b) is positioned on a portion of the cross-section of the columnar body 110, and moreover, it is positioned on the axis of the water pipe 120. Of course, if the center of gravity can be positioned to coincide with the position of the water pipe 120, various arrangements can be adopted, such as arranging the two upper weights 150 symmetrically with respect to the water pipe 120. For convenience, the function of positioning the water pipe 120 towards the seawater side by aligning the center of gravity of the upper weights 150 with the position of the water pipe 120 will be referred to here as the "eccentric function."

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

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

[0042] Instead of the ballast discharge pipe 152 and ballast valve 153 shown in Figure 4, a configuration can be adopted in which a remotely operated "opening / closing door" is provided on the ballast container 151. That is, the ballast BL contained in the ballast container 151 is discharged by opening the opening / closing door via remote operation by an operator. In this case, in addition to seawater, concrete or steel weights can be used as ballast BL.

[0043] To eliminate the eccentric function caused by the upper weight 150, instead of removing part (or all) of the upper weight 150, the adjustment weight 160 shown in Figure 5 can be used. By adding this adjustment weight 160, the eccentric function caused by the upper weight 150 is eliminated. For example, in Figure 5(a), the adjustment weight 160 is placed opposite the upper weight 150 (above in the figure), and in Figure 5(b), the adjustment weight 160 is placed around the entire inner circumference of the columnar body 110 (excluding the upper weight 150). In both cases, the center of gravity in the cross-section of the columnar body 110 is roughly at the center, meaning that the eccentric function caused by the upper weight 150 is eliminated.

[0044] When adding the adjustment weight 160, it is preferable to have a configuration that allows for remote operation by an operator. For example, a configuration can be provided in which a compartment for containing seawater is held, and the adjustment weight 160 can be added by remotely pouring seawater into the compartment. Alternatively, the adjustment weight 160 can be initially placed in a position where the eccentric function of the upper weight 150 is ensured, and the adjustment weight 160 can be moved remotely to a position where the eccentric function is eliminated.

[0045] (Storage tube) The water supply pipe 120 is in contact with seawater at the intake port 120E and communicates with the inside of the columnar body 110 at the discharge port 120D, and is used when raising the spar-type floating body 100. 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 position, the discharge port 120D may be located below the water surface, as shown in Figure 8(e) described later. In that case, more seawater will be injected into the columnar body 110, and as a result, the columnar body 110 may sink beyond its planned draft. Therefore, when the spar-type floating body 100 is in operation, it is necessary to prevent seawater from being injected from the discharge port 120D.

[0046] The housing pipe 170 is attached to the inner surface of the columnar body 110 and has the function of preventing seawater from being injected from the drain port 120D when the spar-type floating body 100 is in operation. Specifically, as shown in Figure 6, the housing pipe 170 has a double-pipe structure in which the water passage pipe 120 is housed inside the housing pipe 170. However, the housing pipe 170 has a watertight structure that prevents seawater from entering from the outside. This prevents seawater from flowing into the water passage pipe 120 from the drain port 120D when the spar-type floating body 100 is in operation. Furthermore, as shown in Figure 2, if vertical ribs 111 are provided on the inside of the columnar body 110, the housing pipe 170 can also be formed by using adjacent vertical ribs 111. In other words, by attaching plate-like material to two adjacent vertical ribs 111 to seal the "gap" from the inside, and further sealing the bottom and top surfaces with plate-like material, a watertight housing pipe 170 is formed.

[0047] On the other hand, when erecting the spar-type floating body 100, it is necessary to discharge the seawater that has flowed into the water passage pipe 120 from the water intake 120E into the columnar body 110 through the drain outlet 120D. For this reason, as shown in Figure 7, an opening 172 is provided on the top side of the housing pipe 170, and an opening / closing cover 171 is provided to seal this opening 172 with water. When erecting the spar-type floating body 100, as shown in Figure 7(b), the opening 172 is opened by removing the opening / closing cover 171 to connect the drain outlet 120D with the inside of the columnar body 110. When the spar-type floating body 100 is in operation, the opening 172 is sealed by installing the opening / closing cover 171 as shown in Figure 7(a), making the inside of the housing pipe 170 watertight.

[0048] (Example of use) The procedure for uprighting the spar-type floating body 100 of the present invention will be described below with reference to Figure 8. Figure 8 is a step diagram showing the procedure for uprighting the spar-type floating body 100 of the present invention. As shown in this figure, first the spar-type floating body 100, which is lying on its side, is towed to a pre-selected calm area. However, at this time, the columnar body 110 is still hollow with no seawater injected inside, and the opening / closing means 130 is closed (plugged), that is, no seawater flows in from the water intake 120E. With the opening / closing means 130 closed and the inside of the columnar body 110 hollow, as shown in Figure 8(a), the bottom weight 140 causes the water intake 120E to be positioned in the seawater, and the eccentric function of the upper weight 150 causes the water passage pipe 120 to be positioned on the seawater side (i.e., the bottom side). For convenience, the state shown in Figure 8(a) will be referred to here as the "sideways state".

[0049] When the spar-type floating body 100, which is lying on its side, is towed by the columnar body 110 to a calm area, the opening / closing mechanism 130 is opened (plugged). In cases where a storage pipe 170 is provided, the opening 172 is opened by removing the opening / closing cover 171. This allows seawater to flow in naturally from the intake port 120E, and the seawater that has flowed through the water passage pipe 120 is then injected into the columnar body 110 from the discharge port 120D. As seawater accumulates inside due to the injection, the columnar body 110 rotates (tilts) under its own weight, as shown in Figure 8(b), so that the bottom of the columnar body 110 sinks into the sea and the column axis approaches vertical (counterclockwise in the figure).

[0050] As seawater is injected, and the discharge port 120D reaches sea level as shown in Figure 8(c), the inflow of seawater from the intake port 120E stops. Consequently, the rotation (erecting) of the columnar body 110 is also interrupted, and the columnar body 110 is tilted toward the upper weight 150 side (right side in the figure) (hereinafter referred to as the "intermediate state"). Once the columnar body 110 is in the intermediate state, part (or all) of the upper weight 150 is removed. As a result, as shown in Figure 8(d), the columnar body 110 is in a state where the column axis is approximately vertical (including vertical) due to the elimination of the eccentric function caused by the upper weight 150 (i.e., upright state). Alternatively, instead of removing the upper weight 150, an adjustment weight 160 can be added.

[0051] Once the columnar body 110 is in an upright position, the opening / closing mechanism 130 is closed (sealed), and ballast such as crushed stone or seawater is poured into the columnar body 110 until the planned draft is reached. At this time, the ballast can be poured in from the opening at the upper end of the columnar body 110. In cases where a storage pipe 170 is provided, the opening 172 is sealed by installing the opening / closing cover 171 before pouring in the ballast. Once the upright columnar body 110 is submerged to the planned draft, the wind turbine section is attached to the columnar body 110 to construct the spar-type floating body 100, as shown in Figure 8(e).

[0052] 2. Method for erecting a spar-type floating structure Next, the method for erecting the spar-type floating body of the present invention will be explained in detail with reference to Figure 9. The method for erecting the spar-type floating body of the present invention is a method for erecting the spar-type floating body 100 described above. Therefore, explanations that overlap with those described for the spar-type floating body 100 will be avoided, and only the aspects specific to the method for erecting the spar-type floating body of the present invention will be explained. In other words, anything not described here is the same as what was explained in "1. Spar-type floating body".

[0053] Figure 9 is a flowchart showing the main steps of the spar-type floating body erection method of the present invention. As shown in this figure, first the spar-type floating body 100 is manufactured in a dry dock or the like (Step 201 in Figure 9). Then, targeting a time when the environment, such as tidal level and current, is favorable, the spar-type floating body 100, with its columnar main body 110 lying on its side, is towed by a tugboat or the like to a pre-selected calm area (Step 202 in Figure 9), where the spar-type floating body 100 is temporarily moored (Step 203 in Figure 9).

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

[0055] When the spar-type floating body 100 reaches its planned height, the wind turbine section is installed above the spar-type floating body 100 (Step 209 in Figure 9), and the completed structure consisting of the wind turbine section and the spar-type floating body 100 is constructed and temporarily moored in a calm area (Step 210 in Figure 9). Then, choosing a time when the tide level and currents are favorable, the completed structure is towed to the waterfall area by a tugboat (Step 211 in Figure 9), where the completed spar-type floating body 100 is permanently moored (Step 212 in Figure 9), and the submarine cable is installed on the completed structure (Step 213 in Figure 9). [Industrial applicability]

[0056] The spar-type floating structure and the method for erecting the spar-type floating structure of the present invention can be particularly suitably used for floating offshore wind power generation in sea areas deeper than 50m. Since the present invention allows for the installation of floating offshore wind power generation facilities at low cost and with ease, it can be expected to create a more positive incentive for offshore wind power generation. Furthermore, considering the stable supply of energy while suppressing greenhouse gas emissions, the present invention is not only industrially applicable but can also be expected to make a significant contribution to society. [Explanation of Symbols]

[0057] 100 Spar-type floating body of the present invention 110 Columnar body (of a spar-type floating structure) 111 (Vertical ribs of the columnar body) 112 Transverse ribs (of the columnar body) 120 (Water pipe for spar-type floating structures) 120E (Water intake for water pipe) 120D (Water pipe) drain 130 (Opening and closing means for spar-type floats) 140 (Bottom weight of spar-type float) 150 (Upper weight of spar-type float) 151 (Upper weight) ballast container 152 (Upper weight) ballast discharge pipe 153 (Upper weight) ballast valve 160 (Adjustable weight for spar-type float) 170 (Housing tube for spar-type floats) 171 (Opening / closing cover of the containment tube) 172 (Opening of the containment tube) BL Ballast

Claims

1. A spar-type floating structure that constitutes a floating offshore wind power generation facility, A hollow, columnar body with a bottom weight installed at the base, A water pipe is arranged parallel or substantially parallel to the columnar axis of the columnar body and attached to the inner surface of the columnar body, The system includes an opening / closing means for controlling the inflow of seawater into the water pipe, A water intake is provided on the bottom side of the water passage pipe, and a drain is provided on the top side of the water passage pipe. When the opening and closing mechanism is opened, seawater can flow in from the intake. When the opening and closing mechanism is closed, the inflow of seawater from the water intake is restricted. Before the opening and closing mechanism is closed and seawater is injected into the interior, the columnar body, which is positioned so that the water passage is on the seawater side, floats on the sea surface in a tilted, sideways state by the bottom weight so that the water intake is located in the seawater. When the opening / closing mechanism is opened in the aforementioned lying-down state, seawater flowing in from the intake port is poured into the interior of the columnar body through the drain port via the water passage pipe, causing the columnar body to stand upright while tilting so that the bottom of the columnar body sinks into the sea and the column axis approaches vertical. A spar-type floating body characterized by the following features.

2. The columnar body is further provided with an upper weight that is positioned on the axis of the water pipe, within a portion of the circumferential direction of the columnar body, and is attached to the columnar body. The upper weight is positioned such that, when the columnar body is viewed in cross-section, its center of gravity coincides with the water pipe. Before the opening and closing mechanism is closed and seawater is poured into the interior, the columnar body is tilted on its side by the upper weight so that the water passage faces the seawater side. When seawater is poured into the interior of the columnar body and the drain outlet reaches sea level, the pouring of seawater stops, and the columnar body is placed in an intermediate state where its erection is interrupted. In the aforementioned intermediate state, the columnar body is tilted so as to be closer to the upper weight. The spar-type floating body according to feature 1.

3. Part or all 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 positioned such that the column axis is vertical or approximately vertical. The spar-type floating body according to feature 2.

4. The columnar body is further equipped with an adjustable weight, When the adjustment weight is attached to the columnar body in the intermediate state, the columnar body is positioned such that the column axis is vertical or approximately vertical. The spar-type floating body according to feature 2.

5. The columnar body is further equipped with a housing pipe that houses the water passage pipe, An opening is provided at the top of the aforementioned housing tube. The aforementioned opening is provided with an opening / closing lid that opens and closes the opening. The spar-type floating body according to feature 1.

6. A method for raising the spar-type float described in claim 1 so that it is in an upright position in seawater, The columnar body is placed in the aforementioned lying-down position, the opening and closing mechanism is opened, seawater is allowed to flow in from the water intake, and the pipe water injection process is also provided, in which seawater is injected into the interior of the columnar body from the drain outlet through the water passage pipe. In the aforementioned pipe water injection process, seawater is injected into the columnar body, causing the columnar body to be erected while tilting so that its bottom is submerged in the sea and its axis approaches vertical. A method for erecting a spar-type floating body, characterized by the features described herein.

7. The aforementioned spar-type float further comprises an upper weight, The upper weight is positioned on the axis of the water pipe, within a portion of the circumferential direction of the columnar body, and is attached to the columnar body, and is removable from the columnar body. A transportation process for transporting the spar-type floating body, including the columnar body which is in the lying-down state with the water passage facing the seawater side due to the upper weight, to a destination by sea, The system further comprises a weight removal 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 that has been transported to the destination. When the seawater has been injected into the interior of the columnar body and the drain outlet is at sea level, the injection of seawater stops, resulting in an intermediate state where the erection of the columnar body is interrupted. In the weight removal step, the upper weight is removed from the columnar body which is in the intermediate state, thereby positioning the columnar body so that its axis is vertical or approximately vertical. The method for erecting a spar-type floating body according to feature 6.

Images