JP6683413B2 - Gas tank - Google Patents

Description

  The present invention relates to a gas tank and a gas tank protection method.

  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 formed by excavating the ground. 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 further enclosed. The outer tank is provided with a ventilation hole, and a bellows is attached to this ventilation hole. The bellows expands and contracts according to the volume fluctuation of nitrogen gas. With such a configuration, the volume fluctuation of 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, an independent tsunami protection fence is installed outside the tank. In the reinforcing structure described in Patent Document 3, a support frame is provided below the side plate of the tank, and concrete is poured into 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 storage body gradually increases from one end in the horizontal direction of the storage body toward the central portion. The containment body is set so that one end of it is directed to the side where the intrusion of the tsunami is expected.

JP, 9-137626, A JP, 2007-302281, A JP2012-250712A JP, 2013-1407, A

  In the past, measures against tsunamis or storm surges in breathing tanks or gas storage tanks have been considered so that the installation location does not become a flooded area, but if a tsunami or storm surge can reach the installation location of these gas tanks, Seawater may flow around the gas tank. In that case, water pressure may be applied to the tank body to collapse the tank body, or buoyancy may be applied to the tank body to lift the tank body. In this way, 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, which can prevent the tank body from being crushed and lifted up even when a tsunami or a high tide has arrived.

The present invention is a gas tank in which gas is stored inside a tank main body, the opening being provided on a side wall of the tank main body, the opening communicating with the inside and the outside of the tank main body, and being provided on the side wall so as to close the opening. The tank body is installed on a concrete foundation, and a cylindrical wall buried in the ground is provided below the foundation, and the upper end of the wall is on the lower surface of the foundation. joined walls Rukoto is configured to be able to prevent the wraparound of seawater into the bottom of the foundation, occlusion is by moving or deformed when the tsunami or storm surge tank body has reached , At least a part of the opening is exposed, and seawater is introduced into the inside of the tank main body through the opening to reduce water pressure and buoyancy applied to the tank main body to prevent the tank main body from being crushed and lifted. .

  According to this gas tank, the opening provided on the side surface of the tank body is closed by the closing portion. By moving or deforming the closing portion, at least a part of the opening is exposed, and the inside and outside of the tank body communicate with each other. Therefore, when a tsunami or a high tide reaches the tank body, seawater can be introduced into the tank body by moving or deforming the blockage. When seawater is introduced into the tank body, water pressure and buoyancy applied to the tank body are reduced even when seawater exists around the tank body. Therefore, even if a tsunami or a high tide arrives, it is possible to prevent the tank body from being crushed and lifted.

In some embodiments, tank body has a sidewall, and a bottom plate joined to a lower end of the side wall, the foundation, the anchor member to be exposed is embedded so as to face the peripheral edge of the bottom plate, the bottom plate The peripheral edge of the is welded to the exposed portion of the anchor member over the entire circumference. According to this structure, the anchor member is embedded in the foundation, and the peripheral edge portion of the bottom plate of the tank body is welded to the exposed portion of the anchor member over the entire circumference. This structure prevents seawater from entering the gap between the tank body and the foundation. Therefore, it is possible to prevent the tank body from rising from the foundation.

  In some aspects, the gas tank comprises an opening and closing mechanism that holds the closure in the closed position and allows movement of the closure when water pressure is applied to the closure. In this case, when water pressure is applied to the closed portion, the closed portion moves and the inside and outside of the tank body communicate with each other. Therefore, the seawater can be introduced into the tank body by utilizing the water pressure caused by the arrival of the tsunami or the high tide.

  In some aspects, the gas tank includes a driving unit that moves the closing unit between a closed position and an open position, and a control unit that controls the driving 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 a tsunami or storm surge is enhanced.

  In some embodiments, the occlusion includes a plate member that breaks under hydraulic pressure. In this case, when water pressure is applied to the plate-shaped member of the closed portion, the plate-shaped member is broken and the inside and outside of the tank body communicate with each other. Therefore, the seawater can be introduced into the tank body by utilizing the water pressure caused by the arrival of the tsunami or the high tide.

  In some aspects, the opening and the closing portion are provided at a plurality of positions in the circumferential direction of the tank body. In this case, the plurality of openings facilitates the introduction and circulation of seawater. Therefore, seawater can be introduced into the tank body quickly and easily. Also, by adjusting the direction in which each opening is provided, when a tsunami or storm surge arrives, some openings function as seawater inlets, and other openings function as seawater outlets. You can also In this case, the shock given to the tank body by the tsunami or storm surge can be mitigated.

  According to the present invention, it is possible to prevent the tank body from being crushed and lifted up even when a tsunami or a high tide arrives.

It is a figure which shows schematic structure of the gas storage system provided with the gas tank which concerns on one Embodiment of this invention. FIG. 2 is a front view showing the gas tank in FIG. 1 partially broken away. (A) is a perspective view showing a positional relationship between a foundation, an anchor member and a tank body, and (b) is a sectional view showing a joint structure of a bottom plate of the tank body to the anchor member. It is sectional drawing which shows the opening part and closed part which were provided in the side wall. (A) is a figure which shows the force applied to a tank main body when a tsunami arrives, (b) is a figure which shows the force applied 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 discharged the seawater through a some opening, when a tsunami reached, (b) is a figure which shows the state which took in the seawater in the tank main body. (A)-(c) is a figure which shows various modification modes of an obstruction 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 will be denoted by the same reference symbols, without redundant description. In the embodiments described below, the case where the present invention is applied to a breathing tank of a gas storage system will be described.

  A gas storage system S including a breathing tank will be described with reference to FIG. 1. 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 (variable volume gas supply and discharge auxiliary equipment) 1 of the present embodiment, and a low temperature tank 2 that stores 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 stores 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 (perlite or the like) 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 to maintain an inert atmosphere. The nitrogen gas filling pressure is kept substantially constant by the breathing tank 1 so as not to fluctuate due to changes in outside air temperature and atmospheric pressure.

  The breathing tank 1 is attached to the low temperature tank 2 as an auxiliary machine of 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 foundation 7 made of concrete, for example. For example, the lower portion of the foundation 7 is formed in the ground, and the upper portion of the foundation 7 projects above the ground. The breathing tank 1 includes a tank 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 portion of the tank body 8 has a cylindrical shape, and the upper portion 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 its peripheral portion 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 filled 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 of the diaphragm 9. The weight of the weight 12 pressurizes the nitrogen gas in the lower space 10. The central portion of the diaphragm 9 moves up and down as the volume of nitrogen gas changes due to changes in the outside air temperature and atmospheric pressure. By raising and lowering the diaphragm 9, the nitrogen gas filling 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 disc-shaped bottom plate 14 joined to the lower end of the cylindrical side wall 8a. The lower surface of the bottom plate 14 is in contact with the surface of the base 7. The bottom plate 14 can be formed by, for example, joining a plurality of steel plates.

  As shown in FIGS. 3A and 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 base 7 so as to face the peripheral portion 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 portion of the bottom plate 14 is placed on the ring anchor 15, and is welded to the exposed surface 15 a of the ring anchor 15 over the entire circumference. That is, a welded portion 15b is formed over the entire circumference between the peripheral edge of the bottom plate 14 and the exposed surface 15a of the ring anchor 15. With such a joint structure (seal 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 flowing into 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 ( Closing portion) 17. The opening 16 and the lid 17 are, for example, circular. The opening 16 and the lid 17 may have a rectangular shape. The opening 16 and the lid 17 are provided at a plurality of positions in the circumferential direction of the tank body 8. More specifically, the opening 16 and the lid 17 are provided at the bottom 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 a high tide arrives, the opening 16 is exposed by opening the lid 17, and seawater can be taken into the inside through the opening 16. With such a configuration, it is possible to prevent the tank body 8 from being crushed, lifted, and damaged. The tank body 8 is provided with nozzles, manholes, etc., as appropriate, but these are not shown.

  The configurations of the opening 16 and the lid 17 will be described in more 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 body 8, and may be provided more on the side facing the sea, for example. The respective openings 16 and the lid 17 may have the same shape and size, or may have different shapes and sizes.

  Explaining an example of the lid portion 17 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 fitted into the circular opening portion 16 and a flange portion 17b protruding radially from the fitting portion 17a. 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 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 17 and the side wall 8a. The opening / closing mechanism 18 may include, for example, a hinge structure. The opening / closing mechanism 18 holds the lid 17 in the closed position (the position indicated by the solid line in FIG. 4) during normal operation when water pressure does not act on the lid 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 the open position (the position indicated by a virtual line in FIG. 4) by water pressure. When the water pressure does not act on the lid portion 17, the lid portion 17 returns to the closed position by its own weight, for example. The opening / closing mechanism 18 may include a spring mechanism that urges the lid portion 17 to the closed position.

  The lid 17 is provided, for example, on the inner surface side of the tank body 8. It should be noted that all the lid portions 17 may be provided on the inner surface side of the tank body 8 and opened to the inner surface side, but some lid portions 17 are provided on the outer surface side of the tank body 8 and the outer surface side. It may be possible to adopt a mode in which it opens. By adopting the lid portion 17 that can be opened to the inner surface side of the tank body 8 by water pressure, the opening portion 16 can function as an inlet for the seawater W. On the other hand, by adopting 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 be made to function as the outlet of 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. 5 (a) is a diagram showing the force applied to the tank body 8 when the tsunami arrives, and FIG. 5 (b) 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 the tsunami or storm surge reaches the breathing tank 1, the seawater W may exert a horizontal wave force F1 and a withdrawal force F2 on the tank body 8. Further, as shown in FIG. 5 (b), when the tsunami or storm surge reaches the breathing tank 1, the water pressure P may be applied to the side wall 8 a of the tank body 8 by the seawater W. When the seawater W goes around below the foundation 7, buoyancy F3 can be applied to the tank body 8 and the foundation 7. When the seawater W goes around between the tank body 8 and the foundation 7, buoyancy F4 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, since the seawater W can be introduced into the tank body 8, the horizontal wave force F1 and the extraction Force F2, moment M, water pressure P, buoyancy F3 and buoyancy F4 can be reduced. Note that the lid 17 is not shown in FIGS. 6A and 6B.

  A method of protecting the breathing tank 1 will be described with reference to FIGS. 6 (a) and 6 (b). When a tsunami or storm surge reaches the tank body 8, the lid 17 that has closed the opening 16 opens and moves to the inner surface side of the tank body 8, for example. When the lid 17 is opened, the opening 16 is exposed and the inside and outside of the tank body 8 are communicated with each other. 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 so, the horizontal wave force F1 and the withdrawal force F2 applied to the tank body 8 can be reduced, and the damage to the tank body 8 due to the impact when a tsunami or a high tide arrives can be reduced.

  Furthermore, the seawater W is introduced into the tank main body 8 through the opening 16 to submerge the tank main body 8. 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 the tsunami or the high tide, it is possible to prevent the tank body 8 from being crushed and lifted. By preventing the tank body 8 from rising, it is possible to prevent the tank body 8 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 rising 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 by utilizing the water pressure caused by the arrival of the tsunami or the high tide.

  Moreover, since the seawater W is easily introduced and circulated through the plurality of openings 16, the seawater W can be introduced into the tank body 8 quickly and easily. 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 another opening 16 serves as an outlet for seawater W. It can also function (see FIG. 6A). Thereby, the shock given to the tank main body 8 by the tsunami or the high tide can be mitigated. Furthermore, the damage that the tank body 8 may receive can be reduced.

  Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment. The present invention can take various modifications shown in FIGS. 7 (a) to 7 (c). For example, as shown in FIG. 7A, the breathing tank 1A may include a drive unit 19 that moves the lid 17A and a controller (control unit) 20 that controls the drive unit 19. In this case, the controller 20 can be controlled in the central control room. The lid 17A is slidably movable in an arc shape along the side wall 8a between a closed position that closes the opening 16A and an open position that exposes the opening 16A. The controller 20 controls the drive unit 19 to slide the lid 17A to expose the opening 16A. Since the opening and closing of the lid portion 17A can be remotely controlled, the adaptability to a tsunami or storm surge can be enhanced.

  Further, as shown in FIG. 7B, an L-shaped pipe 21 is attached to the side wall 8a of the tank body 8, and a thin plate-like member that is rupturable by water pressure is attached to the tip end of the pipe 21 facing upward. It may be the breathing tank 1B provided with the member 22. In this case, the plate-shaped member 22 is broken by water pressure, so that the seawater W can be introduced into the tank body 8 through the pipe 21. 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 is provided at the tip of the pipe 23 directed downward. It may be a breathing tank 1C provided with. In this case, the plate-shaped member 24 is broken by water pressure, so that the seawater W can be introduced into the tank body 8 through the pipe 23. Further, when the plate-shaped 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 use the gravity to discharge the seawater W inside the tank body 8 to some extent.

  A mechanism similar to the rupture disc may be provided as the closing portion. Alternatively, a mechanism similar to a revolving door may be adopted as the closing portion. It is not limited to the closed portion that is opened and closed by water pressure and the closed portion that is opened and closed under control, and may be a lid member that is opened and closed by a manual operation. For example, it may be a closed part having a sliding door structure.

  The number of openings and the number of closures provided in the tank body may be one each. It is not limited to the case where a plurality is provided in the circumferential direction, and a plurality may be provided in the height direction.

  A cylindrical wall buried in the ground may be provided below the foundation 7. The wall can be made of concrete or steel. With the structure in which the upper end of the cylindrical wall is joined to the lower surface of the foundation 7, it is possible to prevent the seawater W from wrapping around the underside of the foundation 7 (see buoyancy F3 shown in FIG. 5B). .

  The gas tank of the present invention is not limited to the breathing tank. The present invention can be applied to any gas tank as long as it stores gas inside, and may be applied to 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. When 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 Cover 17 Opening / Closing Mechanism 19 Drive Unit 20 Controller 22 Plate Member 24 Plate Member W Seawater

Claims (6)

A gas tank in which gas is stored inside the tank body,
An opening provided on the side wall of the tank body, which communicates the inside and outside of the tank body,
A closing portion provided on the side wall so as to close the opening,
The tank body is installed on a concrete foundation,
Wherein below the foundation provided buried cylindrical wall in the ground, the wall upper end at the Rukoto is joined to the lower surface of the base of the wall prevents the diffraction of seawater to the lower side of said base Is configured to be able to
The blocking portion moves or deforms when a tsunami or storm surge reaches the tank body, exposing at least a part of the opening portion, and introducing seawater into the tank body through the opening portion, A gas tank configured to reduce water pressure and buoyancy applied to the tank body to prevent the tank body from being crushed and lifted. 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 so as to face the peripheral portion of the bottom plate is embedded in the foundation,
The gas tank according to claim 1, wherein the peripheral portion of the bottom plate is welded to the exposed portion of the anchor member over the entire circumference.   The gas tank according to claim 1 or 2, further comprising: 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. A drive unit for moving the closing unit between a closed position and an open position;
The gas tank according to claim 1, further comprising a control unit that controls the drive unit.   The gas tank according to claim 1, wherein the closed 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 portion and the closing portion are provided at a plurality of positions in a circumferential direction of the tank body.

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