JP2015227182A - Gas tank and protection method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas tank which prevents a tank body from being collapsed and lifted even when a tidal wave or a high tide reaches the gas tank, and to provide a protection method of the gas tank.SOLUTION: In a gas tank 1, a gas is stored in a tank body 8 and includes: an opening part 16 which is provided on a side wall 8a of the tank body 8 and allows the interior and the exterior of the tank body 8 to communicate with each other; and a closing part 17 which is provided at the side wall so as to close the opening part 16. The closing part 17 is moved or deformed to expose at least a part of the opening part 16.

Description

  The present invention relates to a gas tank and a method for protecting the gas tank.

  As described in Patent Document 1, a low-temperature tank including an inner tank and an outer tank is known. This low temperature tank is provided in a pit provided by excavating the underground. A low temperature liquid such as LNG is stored in the inner tank. A cold insulating material is filled between the inner tank and the outer tank, and nitrogen gas is sealed. The outer tank is provided with a vent hole, and a bellows is attached to the vent hole. The bellows expands and contracts according to the volume fluctuation of the nitrogen gas. With such a configuration, the volume fluctuation of the nitrogen gas generated in each part of the low temperature tank is absorbed.

  On the other hand, various techniques for protecting a tank from a tsunami or an earthquake are known. For example, in the tsunami countermeasure work described in Patent Document 2, a self-supporting tsunami protection fence is installed outside the tank. In the reinforcing structure described in Patent Document 3, a support frame is provided at the lower part of the side plate of the tank, and concrete is placed in the support frame. The tank described in Patent Document 4 includes a tank body and a storage body that houses the tank body. The width of the container gradually increases from one end in the horizontal direction of the container toward the center. The containment body is set so that one end is directed to the side where the tsunami is expected to enter.

JP-A-9-137626 JP 2007-302281 A JP 2012-250712 A JP 2013-1407 A

  Conventionally, tsunami or storm surge countermeasures in breathing tanks or gas storage tanks have been studied so that the installation location does not become a flooded area, but if a tsunami or storm surge can reach these gas tank installation locations It is conceivable that seawater flows around the gas tank. In that case, there is a possibility that the tank body may be crushed by applying water pressure to the tank body, or the tank body may be lifted by adding buoyancy to the tank body. Thus, it is difficult to protect the tank body when a tsunami or storm surge arrives.

  An object of the present invention is to provide a gas tank and a method for protecting the gas tank that can prevent the tank body from being crushed and lifted even when a tsunami or storm surge arrives.

  The present invention is a gas tank in which gas is stored inside a tank body, provided on a side wall of the tank body, and provided on the side wall so as to close the opening, and an opening communicating with the inside and outside of the tank body. And at least a part of the opening is exposed by the movement or deformation of the blocking part.

  According to this gas tank, the opening provided in the side surface of the tank body is closed by the closing portion. When the closing portion moves or deforms, at least a part of the opening is exposed, and the inside and outside of the tank main body communicate with each other. Therefore, when a tsunami or storm surge reaches the tank body, the seawater can be introduced into the tank body by moving or deforming the blocking portion. When seawater is introduced into the tank body, water pressure and buoyancy applied to the tank body are reduced even when seawater is present around the tank body. Therefore, even when a tsunami or storm surge arrives, the tank body can be prevented from being crushed and lifted.

  In some embodiments, the tank body is installed on a concrete foundation, and the tank body includes a side wall and a bottom plate joined to a lower end of the side wall, and the foundation faces the peripheral edge of the bottom plate. The exposed anchor member is embedded, and the peripheral edge of the bottom plate is welded to the exposed portion of the anchor member over the entire circumference. According to this configuration, the anchor member is embedded in the foundation, and the peripheral portion of the bottom plate of the tank body is welded to the exposed portion of the anchor member over the entire periphery. Such a structure prevents seawater from entering the gap between the tank body and the foundation. Therefore, it is possible to prevent the tank body from floating from the foundation.

  In some embodiments, the gas tank includes an opening / closing mechanism that holds the closing portion in a closed position and allows movement of the closing portion when water pressure is applied to the closing portion. In this case, when water pressure is applied to the closed portion, the closed portion moves and the inside and outside of the tank main body communicate with each other. Therefore, seawater can be introduced into the tank body using the water pressure resulting from the arrival of a tsunami or storm surge.

  In some embodiments, the gas tank includes a drive unit that moves the closing unit between a closed position and an open position, and a control unit that controls the drive unit. In this case, the control unit can control the drive unit and move the blocking unit. Since it is possible to remotely control the opening and closing of the closed part, the response to tsunami or storm surge is enhanced.

  In some embodiments, the closure includes a plate-like member that is broken by hydraulic pressure. In this case, when water pressure is applied to the plate-like member of the closing portion, the plate-like member is broken and the inside and outside of the tank body communicate. Therefore, seawater can be introduced into the tank body using the water pressure resulting from the arrival of a tsunami or storm surge.

  In some embodiments, the opening and the closing portion are provided at a plurality of locations in the circumferential direction of the tank body. In this case, it is easy to introduce and distribute seawater through the plurality of openings. Therefore, seawater can be quickly and easily introduced into the tank body. In addition, by adjusting the direction in which each opening is provided, when a tsunami or storm surge arrives, one opening functions as seawater inlet and the other opening functions as seawater outlet. You can also. In this case, the impact given to the tank body by a tsunami or storm surge can be mitigated.

  The present invention relates to a method for protecting a gas tank in which gas is stored inside the tank body, and the side wall of the tank body is provided with an opening that communicates the inside and outside of the tank body and a closing portion that closes the opening. Before or when the tsunami or storm surge reaches the tank body, move or deform the closed part to expose at least part of the opening, and introduce seawater into the tank body through the opening. To do.

  According to this method for protecting a gas tank, at least a part of the opening is exposed by moving or deforming the closed portion before or when the tsunami or storm surge reaches the tank body, and the inside and outside of the tank body communicate with each other. To do. And since seawater is introduce | transduced into the inside of a tank main body through an opening part, even when the seawater exists around a tank main body, the water pressure and buoyancy which are added to a tank main body are reduced. Therefore, even when a tsunami or storm surge arrives, the tank body can be prevented from being crushed and lifted.

  According to the present invention, even when a tsunami or storm surge arrives, the tank body can be prevented from being crushed and lifted.

It is a figure showing a schematic structure of a gas storage system provided with a gas tank concerning one embodiment of the present invention. FIG. 2 is a front view showing the gas tank in FIG. (A) is a perspective view which shows the positional relationship of a foundation, an anchor member, and a tank main body, (b) is sectional drawing which shows the joining structure of the baseplate of the tank main body with respect to an anchor member. It is sectional drawing which shows the opening part and obstruction | occlusion part provided in the side wall. (A) is a figure which shows the force added to a tank main body when a tsunami arrives, (b) is a figure which shows the force added to a tank main body and a foundation when a tank main body is surrounded by seawater. (A) is a figure which shows the state which introduced and flowed out seawater through several opening part when a tsunami arrived, (b) is a figure which shows the state which took in seawater inside the tank main body. (A)-(c) is a figure which shows the various deformation | transformation aspect of a obstruction | occlusion part, respectively.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant descriptions are omitted. Embodiment described below demonstrates the case where this invention is applied to the breathing tank of a gas storage system.

  With reference to FIG. 1, the gas storage system S provided with a breathing tank is demonstrated. The gas storage system S is a system for storing a low-temperature liquefied gas such as LNG. The gas storage system S is constructed, for example, on the coast near the sea. The gas storage system S includes a breathing tank (equipment with variable volume gas supply / discharge) 1 of this embodiment and a low-temperature tank 2 for storing LNG and the like. The low temperature tank 2 and the breathing tank 1 are connected by a communication pipe 3.

  The low-temperature tank 2 is a double shell tank, and includes an inner tank 4 that accommodates LNG and the like, and an outer tank 5 that surrounds the inner tank 4. A space 6 formed between the inner tank 4 and the outer tank 5 is filled with a cold insulating material (such as pearlite) for insulating the inside and outside of the low temperature tank 2. That is, the space 6 functions as a cold insulation layer. The space 6 is filled with an inert gas such as nitrogen gas, and an inert atmosphere is maintained. The sealed pressure of the nitrogen gas is kept almost constant by the breathing tank 1 so as not to fluctuate due to changes in the outside air temperature and atmospheric pressure.

  The breathing tank 1 is attached to the low temperature tank 2 as an auxiliary machine for the low temperature tank 2. The breathing tank 1 is a cushion tank provided to absorb the volume change of the nitrogen gas in the space 6 described above. The breathing tank 1 is installed on a concrete foundation 7, for example. For example, the lower part of the foundation 7 is formed in the ground, and the upper part of the foundation 7 protrudes on the ground. The breathing tank 1 includes a tank main body 8 installed on a foundation 7. The tank body 8 is made of a steel plate such as iron, and corresponds to the casing of the breathing tank 1. The lower part of the tank body 8 has a cylindrical shape, and the upper part of the tank body 8 has a dome shape.

  As shown in FIG. 2, the breathing tank 1 includes a rubber diaphragm 9 that vertically separates the internal space of the tank body 8. The diaphragm 9 defines a lower space 10 and an upper space 11 by fixing the peripheral edge of the diaphragm 9 to the inner wall surface of the tank body 8. The lower space 10 is connected to the space 6 of the low temperature tank 2 by the communication pipe 3. The lower space 10 is filled with the same gas as the inert gas sealed in the space 6, for example, nitrogen gas. The top of the tank body 8 is open to the atmosphere, and the upper space 11 is filled with air. A weight 12 is attached to the center portion of the diaphragm 9. The nitrogen gas in the lower space 10 is pressurized by the weight of the weight 12. The central part of the diaphragm 9 moves up and down as the volume of nitrogen gas changes due to fluctuations in the outside air temperature and atmospheric pressure. By raising and lowering the diaphragm 9, the nitrogen gas sealing pressure in the space 6 of the low temperature tank 2 is kept constant. A vent 13 is attached to the top of the tank body 8.

  The tank body 8 includes a disk-shaped bottom plate 14 joined to the lower end of the cylindrical side wall 8a. The bottom surface of the bottom plate 14 is in contact with the surface of the foundation 7. Note that the bottom plate 14 can be formed, for example, by joining a plurality of steel plates.

  As shown in FIG. 3A and FIG. 3B, an annular ring anchor 15 is embedded in the foundation 7. The ring anchor (anchor member) 15 is, for example, a steel material having an L-shaped cross section (cross section perpendicular to the extending direction). The ring anchor 15 may be connected to the reinforcing bar in the foundation 7 by welding or the like. The diameter of the ring anchor 15 is larger than the diameter of the bottom plate 14. The ring anchor 15 is exposed on the surface of the foundation 7 so as to face the peripheral edge of the bottom plate 14. That is, the exposed surface (exposed portion) 15 a of the ring anchor 15 is flush with the surface of the foundation 7. The peripheral edge of the bottom plate 14 is placed on the ring anchor 15 and welded to the exposed surface 15a of the ring anchor 15 over the entire circumference. That is, a welded portion 15 b is formed over the entire circumference between the peripheral edge portion of the bottom plate 14 and the exposed surface 15 a of the ring anchor 15. By such a joining structure (sealing structure), the tank body 8 is firmly fixed to the foundation 7, and seawater enters between the tank body 8 (specifically, the bottom plate 14) and the foundation 7. Is prevented. This prevents seawater from entering the machine part.

  As shown in FIG. 2 and FIG. 4, the breathing tank 1 includes a plurality of openings 16 provided on the side wall 8 a of the tank body 8, and a lid provided on the side wall 8 a so as to close the opening 16 ( Occlusion part) 17. The opening 16 and the lid 17 are, for example, circular. The opening 16 and the lid 17 may be rectangular. The opening 16 and the lid 17 are provided at a plurality of locations in the circumferential direction of the tank body 8. In more detail, the opening part 16 and the cover part 17 are provided in the lower part of the side wall 8a. The opening 16 and the lid 17 are provided, for example, at a position lower than half the total height of the tank body 8.

  The opening 16 and the lid 17 are structures for introducing seawater into the tank body 8 (for example, the lower space 10) when a tsunami or storm surge reaches the breathing tank 1. In the breathing tank 1, when a tsunami or storm surge arrives, the opening 17 is exposed by opening the lid 17, and seawater can be taken into the inside through the opening 16. With such a configuration, the tank body 8 can be prevented from being crushed, lifted and damaged. The tank body 8 is appropriately provided with nozzles or manholes, but these are not shown.

  The structure of the opening part 16 and the cover part 17 is demonstrated in detail. Three openings 16 are formed at equal intervals in the circumferential direction of the tank body 8. Four or more openings 16 may be formed, or two openings 16 may be formed. The openings 16 are not limited to being formed at equal intervals in the circumferential direction of the tank main body 8, and may be provided more on the side facing the sea, for example. Each opening 16 and lid 17 may have the same shape and size, or may have different shapes and sizes.

  An example of the lid portion 17 will be described with reference to FIG. 4. The lid portion 17 is made of iron or the like. The lid portion 17 may include a disc-shaped fitting portion 17a that fits into the circular opening 16 and a flange portion 17b that projects from the fitting portion 17a in the radial direction. The shapes of the fitting portion 17a and the flange portion 17b may be curved along the curved shape of the side wall 8a. A gasket or the like may be provided between the lid portion 17 and the side wall 8a.

  The lid portion 17 is attached to the side wall 8a so as to be openable and closable. An opening / closing mechanism 18 is provided between the lid portion 17 and the side wall 8a. The opening / closing mechanism 18 may include a hinge structure, for example. The opening / closing mechanism 18 holds the lid portion 17 in a closed position (a position indicated by a solid line in FIG. 4) at normal times when water pressure does not act on the lid portion 17. The opening / closing mechanism 18 allows the lid 17 to move when water pressure is applied to the lid 17. The lid portion 17 has a predetermined movable range, and moves to an open position (a position indicated by a virtual line in FIG. 4) by water pressure. When water pressure no longer acts on the lid 17, the lid 17 returns to the closed position, for example, by its own weight. The opening / closing mechanism 18 may include a spring mechanism that biases the lid portion 17 to the closed position.

  The lid portion 17 is provided, for example, on the inner surface side of the tank body 8. In addition, although all the lid parts 17 are provided in the inner surface side of the tank main body 8, and it is good also as an aspect opened to an inner surface side, a part of lid parts 17 are provided in the outer surface side of the tank main body 8, and the outer surface side is provided. You may take the aspect opened to. By employing the lid portion 17 that can be opened to the inner surface side of the tank main body 8 by water pressure, the opening portion 16 can function as an inlet for the seawater W. On the other hand, by employing the lid portion 17 that can be opened to the outer surface side of the tank body 8 by water pressure, the opening portion 16 can function as an outlet for the seawater W (see FIG. 6A).

  Here, the force applied to the breathing tank 1 when a tsunami or storm surge reaches the breathing tank 1 will be considered. FIG. 5A is a diagram showing the force applied to the tank body 8 when a tsunami arrives, and FIG. 5B shows the force applied to the tank body 8 and the foundation 7 when the tank body 8 is surrounded by seawater. It is a figure which shows the force applied.

  As shown in FIG. 5A, when a tsunami or storm surge reaches the breathing tank 1, horizontal wave force F <b> 1 and extraction force F <b> 2 can be applied to the tank body 8 by the seawater W. Further, as shown in FIG. 5B, when a tsunami or storm surge reaches the breathing tank 1, the water pressure P can be applied to the side wall 8 a of the tank body 8 by the seawater W. When seawater W wraps around below the foundation 7, buoyancy F <b> 3 can be applied to the tank body 8 and the foundation 7. When seawater W wraps around between the tank body 8 and the foundation 7, buoyancy F <b> 4 can be applied to the tank body 8.

  According to the breathing tank 1 of the present embodiment, as shown in FIGS. 6A and 6B, the sea wave W can be introduced into the tank body 8, so that the horizontal wave force F <b> 1 and the extraction described above are extracted. Force F2, moment M, water pressure P, buoyancy F3 and buoyancy F4 can be reduced. In FIGS. 6A and 6B, the lid 17 is not shown.

  With reference to FIG. 6 (a) and (b), the protection method of the breathing tank 1 is demonstrated. When a tsunami or storm surge arrives at the tank body 8, the lid portion 17 that has closed the opening portion 16 opens and moves to the inner surface side of the tank body 8, for example. The opening 16 is exposed by opening the lid 17, and the inside and outside of the tank body 8 are communicated. Then, the seawater W is introduced into the tank body 8 through the opening 16.

  Here, as described above, if a part of the opening 16 functions as an outlet for the seawater W, the seawater W can be circulated inside the tank body 8 (see FIG. 6A). By doing in this way, the horizontal wave force F1 and the extraction force F2 which are applied to the tank main body 8 can be reduced, and damage to the tank main body 8 due to the impact at the time of arrival of a tsunami or storm surge can be reduced.

  Further, the tank body 8 is submerged by introducing the seawater W into the tank body 8 through the opening 16. As a result, the water pressure P and the buoyancy F3 applied to the tank body 8 can be reduced. In other words, the pressure difference between the inner and outer surfaces of the tank body 8 can be reduced. Therefore, even when the tank body 8 is surrounded by the seawater W due to a tsunami or storm surge, the tank body 8 can be prevented from being crushed and lifted. By preventing the tank body 8 from floating, the tank body 8 can be prevented from drifting.

  Furthermore, according to the breathing tank 1, the ring anchor 15 is embedded in the foundation 7, and the peripheral edge portion of the bottom plate 14 of the tank body 8 is welded to the exposed surface 15a of the ring anchor 15 over the entire circumference. With this configuration, the seawater W is prevented from entering the gap between the tank body 8 and the foundation 7, and the buoyancy F4 can be reduced. Therefore, it is possible to prevent the tank body 8 from floating from the foundation 7.

  Further, since the opening / closing mechanism 18 is provided, when water pressure is applied to the lid portion 17, the lid portion 17 moves and the inside and outside of the tank body 8 communicate with each other. Therefore, the seawater W can be introduced into the tank body 8 using the water pressure resulting from the arrival of a tsunami or storm surge.

  In addition, since the seawater W can be easily introduced and distributed by the plurality of openings 16, the seawater W can be quickly and easily introduced into the tank body 8. By adjusting the direction in which each opening 16 is provided, when a tsunami or storm surge arrives, one opening 16 functions as an inlet for seawater W, and the other opening 16 serves as an outlet for seawater W. It can also function (see FIG. 6 (a)). Thereby, the impact given to the tank main body 8 by a tsunami or a storm surge can be relieved. Furthermore, damage that the tank body 8 can receive can be reduced.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment. The present invention can take various modifications shown in FIGS. 7 (a) to 7 (c). For example, as shown in FIG. 7A, a breathing tank 1A including a drive unit 19 that moves the lid 17A and a controller (control unit) 20 that controls the drive unit 19 may be used. In this case, the controller 20 can be controlled in the central control room. The lid portion 17A is slidable in an arc along the side wall 8a between a closed position that closes the opening portion 16A and an open position that exposes the opening portion 16A. The controller 20 can control the drive unit 19 to slide the lid portion 17A to expose the opening portion 16A. Since the lid portion 17A can be opened and closed remotely, the response to tsunami or storm surge is improved.

  Further, as shown in FIG. 7 (b), an L-shaped pipe 21 is attached to the side wall 8a of the tank body 8, and a thin plate shape that can be broken by water pressure at the tip of the pipe 21 directed upward. The breathing tank 1B provided with the member 22 may be used. In this case, seawater W can be introduced into the tank body 8 through the pipe 21 by the plate-like member 22 being broken by water pressure. As shown in FIG. 7 (c), an L-shaped pipe 23 is attached to the side wall 8a of the tank body 8, and a thin plate-like member 24 that can be broken by water pressure at the tip of the pipe 23 directed downward. It may be a breathing tank 1C provided with In this case, seawater W can be introduced into the tank body 8 through the pipe 23 by the plate member 24 being broken by the water pressure. Further, when the plate-like members 22 and 24 are broken by water pressure, the inside and outside of the tank body 8 remain in communication. Therefore, after the seawater W is drawn, it is possible to discharge the seawater W inside the tank body 8 to some extent using gravity.

  In addition, you may provide the mechanism similar to a rupture disk as an obstruction | occlusion part. Or you may employ | adopt the mechanism similar to a rotary door as a closure part. It is not limited to a closed portion that is opened and closed by water pressure and a closed portion that is controlled to open and close, and may be a lid member that is opened and closed manually. For example, the closed part of a sliding door structure may be sufficient.

  Each of the opening and the closing part provided in the tank body may be one. The present invention is not limited to the case where a plurality are provided in the circumferential direction, and may be provided in the height direction.

  A cylindrical wall embedded in the ground may be provided below the foundation 7. The wall can be made of concrete or steel plate. By having a structure in which the upper end of the cylindrical wall is joined to the lower surface of the foundation 7, the seawater W can be prevented from wrapping around the lower side of the foundation 7 (see the buoyancy F <b> 3 shown in FIG. 5B). .

  The breathing tank 1 is not limited to being installed on the concrete foundation 7. For example, you may install in the top part or side part of the low-temperature tank 2. FIG. Since the breathing tank 1 is smaller than the low temperature tank 2, for example, the breathing tank 1 may be installed on a pedestal provided so as to protrude laterally from the side wall of the low temperature tank 2.

  The gas tank of the present invention is not limited to a breathing tank. The present invention can be applied to any gas tank as long as it stores gas therein, and may be applied to, for example, a gas tank for storing air, oxygen, nitrogen, or the like. The gas tank according to the present invention may store a non-toxic gas or a toxic gas such as ammonia. In the case of storing toxic gas, equipment for detoxifying the released gas can be added.

1 Breathing tank (gas tank)
7 Foundation 8 Tank Body 8a Side Wall 14 Bottom Plate 15 Ring Anchor 15a Exposed Surface 16 Opening 17 Lid 18 Opening Mechanism 19 Drive 20 Controller 22 Plate Member 24 Plate Member W Seawater

Claims (7)

A gas tank in which gas is stored inside the tank body,
Provided on the side wall of the tank body, and an opening communicating the inside and outside of the tank body;
A closing portion provided on the side wall so as to close the opening,
A gas tank in which at least a part of the opening is exposed by moving or deforming the closing portion. The tank body is installed on a concrete foundation,
The tank body includes the side wall and a bottom plate joined to a lower end of the side wall,
An anchor member that is exposed to face the peripheral edge of the bottom plate is embedded in the foundation,
The gas tank according to claim 1, wherein a peripheral edge portion of the bottom plate is welded to an exposed portion of the anchor member over the entire periphery.   The gas tank according to claim 1, further comprising an opening / closing mechanism that holds the closed portion in a closed position and allows movement of the closed portion when water pressure is applied to the closed portion. A drive unit for moving the closing part between a closed position and an open position;
The gas tank according to claim 1, further comprising a control unit that controls the driving unit.   The gas tank according to claim 1, wherein the closing portion includes a plate-shaped member that is broken by water pressure.   The gas tank according to any one of claims 1 to 5, wherein the opening and the closing portion are provided at a plurality of locations in a circumferential direction of the tank body. A method for protecting a gas tank in which gas is stored inside a tank body, wherein a side wall of the tank body is provided with an opening communicating with the inside and outside of the tank body and a closing portion for closing the opening. And
Before or when a tsunami or storm surge arrives at the tank body, at least a part of the opening is exposed by moving or deforming the closed part, and seawater is passed through the opening inside the tank body. Introduced into the gas tank protection method.

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