JPH06298319A - Storage equipment in underground cavity - Google Patents

Abstract

PURPOSE:To secure the airtightness of high pressure fluid with a simple structure by installing a void from a wall surface of an underground cavity, setting up a tank, whose lower end is opened, in this void and, after filling up this void with water of the same pressure as the high pressure fluid to be stored, storing this high pressure fluid in the tank. CONSTITUTION:When compressed air A is introduced into a tank 20 filled up with water W from a pipeline 22, this compressed air A is stored in an upper part of this tank 20. At that time, since the water W of a volumetric portion in this compressed air A is put back to a storage reservoir 14 after being passed through an interconnecting pipe 12, the compressed air A in the tank 20 is balanced in pressure of water in a cavity 10. In brief, while a specified amount of the compressed air is stored, this air A in the tank 20 and the water in the cavity 10 are balanced with each other at both sides of each interface and a wall surface of the tank 20. In addition, with the introduction of a fluid into the tank 20, buoyancy conformed with the extent of volume of this introduced fluid works on the tank 20, so that it is recommendable that the tank 20 is fixed by an anchor 23 as a flotage preventing means. With this constitution, a stress burden to the tank is reduced and thereby airtightness is thus secured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for storing a high-pressure fluid immiscible with water in an underground cavity, and more particularly to a high-pressure fluid such as compressed air, natural gas, LPG and LNG in an underground cavity. It relates to a device for safe storage.

[0002]

2. Description of the Related Art In the fields of energy storage and leveling of supplied electric power, it is required to store the high-pressure fluid in an underground cavity without leaking it. Conventionally, as a method of storing a fluid such as crude oil or LPG in an underground cavity, a water sealing method that utilizes the water pressure of the groundwater that tries to flow into the cavity and a lining method that has a relatively high airtightness are known. There is.

In the water-sealing method, a rock is dug in a state where a hollow is formed deeper than the groundwater level, and the groundwater pressure is constantly higher than the internal pressure on the wall surface of the hollow, so that a fluid such as crude oil or LPG can be supplied. It is enclosed and stored.

The lining method is to secure the airtightness of the underground cavity with a lining material such as steel, concrete, rubber or the like, and to bear the internal pressure on the surrounding ground.
Generally, high airtightness can be obtained regardless of the fractured condition of the bedrock and the hydraulic condition of the ground.

[0005]

The water-sealing method is simple in principle and structure and has been put to practical use as a storage method for crude oil and LPG having a relatively low vapor pressure. Since the mechanism is not fully understood, for example, 10kg
When storing a high-pressure fluid that exceeds / cm ² f, there remain issues such as the problem of ensuring the airtightness of the bedrock and the investigation method at a large depth to prove it.

Unlike the water-sealing method, the lining method can reduce the installation depth of the cavities as long as an appropriate reaction force against the internal pressure is ensured, regardless of the pore water pressure of the surrounding rock, and thus the shaft excavation cost is high. There is also a merit that can be reduced. On the other hand, there are still unsolved problems such as elongation of the lining material due to internal pressure and treatment of water pressure on the back surface, and the structure for ensuring airtightness is complicated.

An object of the present invention is to solve the above-mentioned problems, and to provide an underground cavity storage device capable of reliably ensuring the airtightness of a high-pressure fluid with a simple structure.

The underground cavity storage device according to the present invention comprises a tank, which is arranged in the underground cavity with a gap from the wall surface of the cavity and has an open lower end, and which has the same pressure as the high-pressure fluid to be stored. And a pipe for high-pressure fluid connected to the tank.

The water filled in the gap preferably communicates with a reservoir installed on the ground, and a valve is preferably interposed in a communication pipe connecting the cavity with the reservoir. Further, it is preferable that the tank is provided with a floating prevention means.

Further, another underground cavity storage device according to the present invention has the same pressure as that of a high pressure fluid to be stored and a tank which is disposed in the underground cavity with a gap from the wall surface of the cavity and whose lower end is open. Water that has the water filled in the gap and is installed between at least an upper surface of the tank and a wall surface that faces the gap, and holds the gap, and water passage means capable of circulating the water,
A high-pressure fluid pipe connected to the tank.

[0011]

[Operation] When a high-pressure fluid is introduced from a pipe into a tank filled with water, the volume of the high-pressure fluid in the tank returns to the reservoir through the communication pipe, and the high-pressure fluid in the tank and the water in the cavity are Balance both at each interface and the wall of the tank.

Even if the high-pressure fluid is repeatedly stored and discharged, the water in the cavity freely flows back and forth between the reservoir and the reservoir via the communication pipe, so that the pressure of the high-pressure fluid in the tank is equal to the pressure of the water in the cavity. Always balanced. For this reason, the in-plane stress generated in the wall of the tank is only due to the head difference of water which is equal to the tank height at the maximum.

In the storage device, the water flow means for holding the gap allows water to freely flow through the gap, and the water pressure quickly acts on the back surface of the tank. Further, since the buoyancy acting on the tank due to the introduction of the high-pressure fluid is transmitted to the bedrock through the water passage means, the tank is prevented from rising.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view showing an outline of a device for storing compressed air in an underground cavity.
Is a tunnel-shaped or spherical cavity provided in the underground rock. The cavity 10 is connected to a reservoir 14 provided on the ground via a communication pipe 12, and therefore the water W in the cavity 10 is connected.
The pressure of the water head acts on. The communication pipe 12 may be taken out from the cavity 10 at the bottom of the cavity 10 as shown in FIG. 1 or at the top of the cavity 10.

Inside the cavity 10, a tank 20 for storing a high pressure fluid that is difficult to mix with water is installed. In this embodiment, the tank 20 whose bottom is completely opened is used.
The shape of the tank 20 is not particularly limited except that the water W is flowing inside the tank 20, and for example, the wall surface of the tank 20 may have a hole penetrating the inner and outer peripheral surfaces.

Depending on the type and capacity of the high-pressure fluid to be stored and other requirements, a plurality of tanks 20 may be installed in the cavity 10, or the inside of the tank 20 may be partitioned by an appropriate wall surface to provide a plurality of storage chambers. It is also optional.

The tank 20 is made of a non-permeable material such as steel or concrete.
Since the tank 20 is not subjected to an excessive stress, a light strength is sufficient.

Reference numeral 22 is a pipe for high-pressure fluid, one end of which is open above the inside of the tank 20. Piping 22
May be inserted through the wall surface of the tank 20.

As the fluid is introduced into the tank 20, a buoyancy force acts on the tank 20 according to the volume of the introduced fluid, so that a lifting prevention means may be required. In the embodiment shown in FIG. 1, the tank 20 is fixed by the anchor 23 as a lifting prevention means, but in addition, the tank 2 is fixed.
By properly selecting the constituent material of 0, its own weight is made to be more than the buoyancy, or a cushioning material is interposed in the space between the top of the tank 20 and the ceiling of the cavity 10, so that the above buoyancy is exerted by the upper bedrock. A pressing method or the like can be adopted. In this case, the cushioning material is preferably a water-permeable material such as pumice or aggregate.

Next, the operation of this embodiment will be described. Figure 1
In, when the compressed air is introduced from the pipe 22 into the tank 20 filled with the water W, the compressed air A is stored in the upper portion of the tank 20. At this time, the volume W of compressed air A
Returns to the reservoir 14 through the communication pipe 12, so the tank 2
The compressed air A in 0 is in pressure balance with the water W in the cavity 10. That is, while the predetermined amount of compressed air is stored, the compressed air A in the tank 20 and the water W in the cavity 10 balance at both the respective interfaces and the wall surface of the tank 20.

Even if the compressed air A is repeatedly stored and discharged, the water W in the cavity 10 passes through the communication pipe 12 and the reservoir 1
The pressure of the compressed air A in the tank 20 is always in balance with the pressure of the water W in the cavity 10 since it freely travels back and forth between the tanks 4 and 4. Therefore, the in-plane stress generated in the wall of the tank 20 is only due to the head difference of water which is equal to the tank height at the maximum. Therefore, no excessive stress is generated on the wall surface of the tank 20, which is advantageous in ensuring the airtightness. Also,
Since the internal pressure of the cavity is constant, the influence on the surrounding rock is small.

Further, even if the tank 20 is damaged, the compressed air A temporarily stays inside the cavity and does not suddenly leak to the outside.

Next, another embodiment of the present invention will be described with reference to FIG. 2, in which the same members as those in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted. The storage device shown in FIG. 2 is capable of storing high-pressure fluid even if the device is constructed in a relatively shallow portion.

A valve 16 is provided in the communication pipe 12 connecting the cavity 10 and the reservoir 14. The valve 16 may be of any type such as a sluice valve or a globe valve as long as it is for high pressure. A valve 16 in the communication pipe 12
There are no special restrictions on the location of the installation.

Reference numeral 18 is a bypass pipe of the communication pipe 12, which is provided so that the water W in the cavity 10 can freely flow and the water pressure can quickly act on the back surface of the tank 20. Further, a backing material 26 having high water permeability is provided between the outer wall surface of the tank 20 and the inner wall surface of the cavity 10.

In the storage device shown in FIG. 2, similarly to the storage device shown in FIG. 1, when the valve 16 is closed with the compressed air A stored near the bottom of the tank 20, the compressed air in the tank 20 is closed. In A and the water W in the cavity 10,
The water head H of the communication pipe 12 is applied. Therefore, if high-pressure compressed air is further supplied into the tank 20 from the pipe 22, the water W in the cavity 10 is pressurized, and the compressed air A in the tank 20 and the water W in the cavity 10 form respective interfaces. Balance both on the wall of the tank 20. In addition, in this storage device, the same high water pressure as the compressed air A is applied to the surrounding rocks, so the surrounding bedrock must have strength conditions that can withstand it and conditions that the hydraulic conductivity is small to a certain extent and that there is little water loss. .

Next, a water passage means 21 is provided on the outer peripheral portion of the tank 20.
An embodiment provided with will be described. As shown in the enlarged cross-sectional view of FIG. 3, the water-passing means 21 is composed of three layers of a water-passing plate 24, a water-permeable sheet 25, and back-filling concrete 26 from the side closer to the outer wall of the tank 20.

The water passage plate 24 is the same as that shown in FIG.
As shown in the perspective view of FIG. 1, the plate 24 is formed in a corrugated shape with a water passage hole 28. Due to this corrugated shape, a water circulation space is secured in the gap between the outer wall surface of the tank and the inner wall surface of the cavity 10, and the plate 24 is reinforced. Therefore, the shape of the water passage plate 24 may be any structure as long as it is water-permeable, can retain water, and has a strength capable of transmitting the buoyancy acting on the tank 20 to the bedrock. A honeycomb shape, a surface uneven shape, or the like can also be used.

The water-permeable sheet 25 is made of backfill concrete 2
It plays a role of a form when placing 6, and also plays a role of guiding groundwater that permeates from the surrounding rock to the water plate 24, and a commonly used civil engineering sheet can be used. The water passage plate 24 and the water permeable sheet 25 may be attached to the tank 20 in advance.

The back-filled concrete 26 is the permeable sheet 2
This is for filling the gap between the rock 5 and the bedrock and transmitting the buoyancy acting on the tank 20 to the bedrock. As the backfill concrete 26, a normal mortar concrete can be used, but a concrete having a high water permeability is particularly desirable.

Next, the operation of this embodiment having the water passage means 21 will be described. When the compressed air is introduced from the pipe 22 into the tank 20 filled with the water W, the compressed air A is stored in the upper portion of the tank 20. At this time, the volume W of the compressed air A is contained in the communication pipe 12. At the same time as returning to the reservoir 14 through the water, the water W held on the water passage plate 24 freely flows through the water passage hole 28.

Therefore, the water pressure of the water W quickly acts on the back surface of the tank 20, and the compressed air A in the tank 20 and the water W in the water passage means 21 are pressure balanced through the wall surface of the tank 20. . That is, while the predetermined amount of compressed air is stored, the compressed air A in the tank 20 and the water W in the cavity 10 balance at both the respective interfaces and the wall surface of the tank 20.

The water passage means 21 may be provided on all of the top and side surfaces of the tank 20, or from the viewpoint of preventing the tank 20 from floating, only the top portion may be installed.

[0034]

According to the present invention, since the pressure of the high-pressure fluid stored in the tank and the pressure of the water in the cavity are always in a balanced state, the stress load on the tank is small and the storage tank has a slight structure. Can also be expected to have reliable airtightness. Further, since a constant pressure is constantly applied to the inner surface of the cavity, it has an excellent effect that the stability against the surrounding rock is extremely high.

Further, even if the tank is damaged,
Since the stored high-pressure fluid is not directly discharged to the outside world, the safety is high.

In the storage device in which a valve is interposed in the communication pipe, the construction depth of the cavity can be made shallow if the strength conditions of the ground around the underground cavity are the same.

In the storage device in which the water passage means is provided at the top of the outer peripheral surface of the tank, the water passage means can prevent the tank from floating and at the same time make it possible to exert a water pressure on the back surface of the tank without fail, so that the tank is not stressed. Can be made extremely small

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an outline of a storage device in an underground cavity.

FIG. 2 is a cross-sectional view showing the outline of another underground cavity storage device.

FIG. 3 is an enlarged cross-sectional view of a water passage means provided on the outer peripheral portion of the tank.

FIG. 4 is a partial perspective view of a corrugated water-passing plate.

[Explanation of symbols]

 10 Underground Cavity 12 Communication Pipe 16 Valve 14 Reservoir 20 Tank 21 Water Flow Means 22 High Pressure Fluid Pipe 23 Floating Prevention Means (Anchor) 24 Water Flow Plate 25 Water Permeable Sheet 26 Backfill Concrete 28 Water Hole

Claims (5)

[Claims] 1. A tank, which is arranged in a subterranean cavity with a gap from a wall surface of the cavity and has an open lower end, and water having the same pressure as the high-pressure fluid to be stored and filling the gap.
An underground cavernous storage device comprising a high-pressure fluid pipe connected to the tank. 2. The underground cavity storage device according to claim 1, wherein the water filled in the gap communicates with a reservoir installed on the ground. 3. The underground cavity storage device according to claim 2, wherein a valve is interposed in a communication pipe connecting the cavity and the reservoir. 4. The underground cavity storage device according to claim 1, wherein the tank is provided with a floatation preventing means. 5. A tank, which is arranged in the underground cavity with a gap from the wall surface of the cavity and has an open lower end, and water having the same pressure as the high-pressure fluid to be stored and filling the gap.
At least an upper portion of the tank and a wall surface facing each other, which is provided with a water passage means which holds the gap and allows the water to flow, and a high-pressure fluid pipe connected to the tank. Storage device in underground cavern.