JPH0337500A - Method for storing high pressure gas in base rock and base rock tank for storing high pressure gas - Google Patents

Abstract

PURPOSE:To store the huge capacity of high pressure gas at low cost by providing the container body of a flexible structure which is hermetic and perissible for possible deformation due to external force, thereby regulating ground water pressure exerting on the back surface side of said container body in response to the internal pressure of said container body. CONSTITUTION:When high pressure gas is stored in the container body 12 of a tank main body T, the container body 12 is subjected to internal pressure while being deformed toward the wall surface 18a of a wall body 18 so as to be closely adhered thereto so that its internal pressure is backed up by a base rock 1 via a stress transmitting layer 14 composed of the wall body 18 and sprayed concrete 13. When storing pressure within the tank T is dropped because of discharging stored gas G, the container body 12 is restored to its original condition. In this case, the amount of ground water equivalent to the deformation of the container body 12 is supplied from a storing space 27 or a foundation around a cavity through a conduit 25 to the stress transmitting layer 14, ground water in the storing space is discharged out through a discharge means 28 in such a way that ground water pressure exerting on the back surface of the container body 12 is balanced with the internal pressure of the container body 12, the container body 12 will never be thereby subjected to external force exerted by ground water.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a method for storing high-pressure gas in rock and a rock tank for storing high-pressure gas, and in particular, to realize storage of a large amount of high-pressure gas at low cost. The present invention relates to a method for storing high-pressure gas in rock and a rock tank for storing high-pressure gas.

[Conventional technology]

As is well known, high-pressure gas and the like are usually stored in spherical tanks or cylindrical tanks installed on the ground. These conventional high-pressure gas storage tanks are often made of a steel plate or the like having a thickness of, for example, several tens of millimeters so as to withstand the storage internal pressure.

[Problem to be solved by the invention]

However, the above-mentioned conventional high-pressure gas storage tanks have a small storage capacity, and if a large-capacity storage facility is targeted, the material cost will be enormous due to the tank or huge structure, and the construction space will not be used on the ground surface. There is a problem that it requires a large area. Furthermore, even if these tanks are installed underground, they must be constructed with a structure that can withstand high internal pressure, which solves site-related problems, but construction costs are still enormous for large-capacity tanks. There are problems such as this.

On the other hand, in recent years, the concept of a water seal system has been proposed, which utilizes underground rock cavities as they are and stores liquid or high-pressure gas using the groundwater pressure around the cavities. FIG. 8 shows an example of the structure, in which a storage space 2 is formed within a rock 1. Reference numeral 3 is a pipe for receiving and discharging stored gas, and reference numeral 4 is a pipe for supplying and discharging water to lower the level of waterbed 5, which maintains the storage pressure of stored gas at a constant level.
This is a conduit for discharge. In this method, the internal pressure P of the stored gas G
By balancing the groundwater pressure and P2, the gas G
The aim is to realize high-pressure storage of

Since this method does not use artificial industrial materials such as steel plates as the storage tank structure, it can be economical for oils and the like where the pressure is relatively low. However, in the case of high-pressure storage, the installation depth is large due to the need to balance the storage pressure with groundwater pressure, resulting in high costs.

For example, if the pressure (internal pressure) of stored gas G is 100 kg
/cm2, a simple calculation shows that the storage space 2 needs to be formed at a depth of 1000 m or more in order to obtain groundwater pressure that balances the internal pressure. Furthermore, since the groundwater comes into direct contact with the stored material, there are also problems such as leakage of groundwater into the storage space 2 and dissolution of the stored material into the groundwater.

The present invention has been made in view of the above-mentioned circumstances, and provides a rock-based storage method for high-pressure gas and a high-pressure gas storage method that eliminates the above-mentioned problems and enables storage of a large volume of high-pressure gas at low cost. The second purpose is to realize a rock tank for industrial use.

[Means to solve the problem]

The method for storing high-pressure gas in rock formation according to claim 1 of the present invention includes:
When storing high-pressure gas in rock, a flexible structure container body that is airtight and allows deformation against external forces is provided in a cavity formed in the rock mass, and the stored gas is stored inside the flexible structure container body. It is characterized in that the underground water pressure existing on the back side of the flexible structure container is regulated according to the internal pressure of the flexible structure container.

In addition, in the rock tank for high-pressure gas storage according to claim 2, a flexible structure container body that has airtightness and allows deformation in response to external pressure is configured inside a cavity formed in the rock mass. A water permeable stress transmission layer is provided between the ground and the wall surface, and the stress transmission layer is communicated with underground water pressure adjustment means through a water conduit. be.

The high-pressure gas storage rock tank according to claim 3 is the high-pressure gas storage rock tank according to claim 2, in which the underground water pressure adjusting means is provided in a water storage space provided separately from the cavity in the rock, and in the water storage space. It is characterized by comprising a drainage means for discharging groundwater stored in the space.

[Effect]

When high-pressure gas is sealed inside a flexible structure container, this flexible structure container allows deformation due to external pressure. Supported. At this time, since the groundwater pressure existing on the back side of the flexible structure container increases, a part of the groundwater escapes into the water storage space through the water conduit and is discharged from the back side of the flexible structure container.

On the other hand, the internal pressure of the flexible structure container decreases as the stored gas is discharged, the flexible structure container deforms accordingly, and an amount of groundwater corresponding to the internal pressure of the container flows from the groundwater adjustment means to the container via the conduit. It is supplied to the back.

At the same time, groundwater around the cavity also collects.

Moreover, the storage space and the groundwater are separated by the flexible structure container, and the stored material and the groundwater do not come into direct contact with each other.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

1 and 2 show a first embodiment of the present invention, and the one indicated as a whole by the reference numeral 10 in the figures is a rock tank for high-pressure gas storage (hereinafter abbreviated as "rock tank") according to the present invention. ).In addition, numeral 31 is a ground facility, 23 is,
This is a shirt I for connecting the rock tank 10 and the ground facility 31 and for receiving and discharging gas.

This rock tank 10 has a reta cavity 11 formed in the bedrock 1.
A container body (flexible structure container body) 12 having airtightness and allowing deformation in response to external pressure is placed inside the cavity 11, and a stress transmission layer 14 having water permeability is placed between the wall surface 1a constituting the cavity 11. The structure is characterized in that the stress transmission layer 14 is connected to a groundwater pressure adjusting means 26 via a water conduit 25.

The tank body T constituting this rock tank 10 has the cross-sectional structure shown in FIG. 1 and described in detail below, and extends into the rock mass 1 as shown in a side view in FIG. 2. .

The cavity 11 is formed by excavating the bedrock 1 using a drilling device or the like brought in from a shaft (not shown), and in this embodiment, the cavity 11 has a width of 10 m to 20 m and a height of 15 m to 25 m. The length is arbitrarily set depending on the planned storage capacity. This cavity 1■ is Rosokubor 1-15.15.・
・Supported and reinforced by.

As shown in FIG. 3, the wall surface 1a constituting the cavity 11 is entirely lined with sprayed concrete 13. However, the action of the concrete 13 in this spraying is not intended to seal the wall surface 1a, but to level out the uneven wall surface 1a formed by excavation.

Further, inside the sprayed concrete 13, a wall body 18 is constructed of concrete 16 and reinforcing bars 17 buried within this concrete 16. The concrete 16 here is porous and has excellent water permeability and high strength. Further, in this case, the wall 18 made of the concrete 16 is not integrated in its entirety, but is made up of a plurality of blocks 19, 19, at least in the direction in which the ring is formed, which has a substantially closed ring shape in cross section. The block 19 is divided into two parts, and each block 19 is separated by a joint material 20. In this case, asphalt is used as the joint material 20. In this embodiment, the wall 18 is divided into blocks 1919 in its longitudinal direction as well. Further, in this case, the reinforcing bars 17 are made of FRP (fiber reinforced plastic) in consideration of rust prevention against groundwater and deformation tolerance.

In this embodiment, the sprayed concrete 13 and the wall 18 constitute a stress transmission layer 14.

Further, a container body 12 is formed inside the wall body 18. In this case, this container body 12 has a large number of steel plates 2],
, 21. ... are welded and connected in the width direction and length direction, making it airtight. Further, the thickness of these steel plates 21 is several cm (here, around Icm), so that the container body 12 is easily deformed ( (expansion).

As shown in FIG. 1, the water conduit 25 extends from the bottom of the tank body T having the above-mentioned cross-sectional structure, extends in the rock mass 1 in a substantially horizontal direction, and also extends within the rock mass 1 in a substantially horizontal direction. It terminates at a water storage space 27 formed in . The water conduit 25 is made of sand and gravel, for example, and has extremely high water permeability. Also,
In this case, as shown in FIG. 3, sprayed concrete 13 is not applied to the bottom of the tank body T, and that part is made of gravel, etc., thereby preventing the flow of underground water from the tank body T to the water conduit 25. Alternatively, underground water can flow smoothly from the water conduit 25 to the tank body T.

The water storage space 27 is formed in the bedrock 1 at a position relatively close to the tank body T, with its bottom surface level substantially matching the bottom surface level of the tank body T. Further, this water storage space 27 is provided with a drainage means 28 for discharging the groundwater stored in the water storage space 27 from the water storage space 27. The drainage means 28 in this case consist of a submersible pump 29 and a drainage shaft 30 connected to this submersible pump. In this embodiment, the water storage space 27 and the drainage means 28 constitute the underground water pressure regulating means 26 according to the present invention.

The following procedure is used to construct the high-pressure gas storage rock tank 10 having the above configuration.

First, by excavating the underground bedrock 1, a cavity 11 for the tank body T and a water storage space 27 are formed.Furthermore, these wall surfaces 18, etc. are protected by the rock bolts 15, etc., and the sprayed concrete 13 is construction. The water conduit 25 is also constructed at the same time as the cavity 11 and the water storage space 27 are excavated.

Next, the spraying forms the wall 18 by placing the concrete 16 on the inner surface of the concrete 13. Before pouring the concrete 16, the reinforcing bars 17 are buried in advance. In addition, since the wall 18 has a structure divided into blocks as described in -1-, in this case, the concrete 16 is added to the height divided by the joint material 20. do.

Once the wall 18 is constructed as described above and the stress transmission layer 14 is formed by the wall 18 and the sprayed concrete 13, the inner wall surface of this stress transmission layer 14, that is, the wall 1
The steel plate 2121. The container body 12 is constructed by assembling... The steel plates 21 are manufactured in advance at a factory, and the steel plates 21.21.・・・
The container body 12 is constructed by welding them on-site.

Then, a shaft 2 for receiving and discharging is attached to the container body 12.
3, and also connect the drainage shaft 3 to the water storage space 27.
0 is connected to complete the high pressure gas storage rock tank 10.

Next, the operation of the high-pressure gas storage rock tank 10 configured as described above will be explained.

In a state where high-pressure gas is stored in the container body 12 of the tank body T, this container body 12 receives internal pressure, and following this, the container body 12 deforms (expands) toward the wall surface 18a of the wall body 18. They are in close contact and transmit internal pressure to the wall 18. wall 18
The internal pressure transmitted to the concrete
is transmitted to the bedrock 1 via. That is, the storage pressure of the high-pressure gas is supported by the rock mass 1 via the stress transmission layer 14 (wall 18 + sprayed concrete 13). That is, by forming the stress transmission layer 14 between the container body 12 and the wall surface 1a of the rock l, the container body 12
The stress generated in the container body 12 can be effectively transmitted evenly to the uneven wall surface 1a without causing stress concentration in a specific location of the container body 12. Further, in this case, since the wall body 18 has a divided structure as described above, the deformation of the container body 12 can be more efficiently transmitted to the rock mass l.

Since the wall body 18 constituting the stress transmission layer 14 has water permeability and contains groundwater inside, the wall body 18 is caused by deformation of the container body 12 and accompanying deformation of the rock mass 1. The groundwater contained within 18 is pressurized,
A part of it escapes to the water conduit 25 and is stored in the water storage space 27. As a result, the water level in the water storage space 27 rises by two degrees, and the groundwater that exceeds the predetermined water level is discharged by the drainage means 28.

By the way, as mentioned above, the sprayed concrete 13 is provided to improve the filling properties of the poured concrete 16 by leveling out the unevenness of the wall surface 1a of the rock 1, and if possible, , the stress transmission layer 14 may be composed of one layer. Also, here, the wall 18
Although the wall 18 is made of high-strength porous concrete, the wall 18 does not necessarily have to be made of concrete, but may be made of other materials or structures as long as it has excellent water permeability and strength. It may be.

On the other hand, when the storage pressure inside the tank body T (inside the container body 12) decreases due to discharging of the stored gas G, the container body 12 deforms (returns to its original state) accordingly. At this time, if the condition remains as it is, groundwater in an amount commensurate with the deformation of the container body 12 will flow from the water storage space 27 via the water conduit 25 or from the ground around the cavity 11 to the stress transmission layer 14 (wall body 18
), but here, the groundwater in the water storage space 27 is discharged by the drainage means 28 so that the groundwater pressure on the back side of the container body 12 is balanced with the reduced internal pressure of the container body 12. In other words, the operation is performed so that groundwater is not drawn back to the back side of the container body 12 (ie, the stress transmission layer 14) as much as possible.

As a result, even when the stored gas G is discharged and the internal pressure of the container body 12 decreases, the container body 12 will not be subjected to strong external pressure due to groundwater, so that the container body 12 can be relatively It becomes possible to construct a flexible structure by using a steel plate 21 with a small thickness.

For high internal pressure (storage pressure), the container body 1
Since the internal pressure is supported by the rock mass 1 by the modification of 2, it becomes possible to construct a large-capacity storage tank as described above at low cost.

Figures 4 to 6 respectively show changes in storage internal pressure (Figure 4) corresponding to the intake and discharge of stored gas G as described above, external force acting on rock cavity 11 (Figure 5), groundwater pressure, and water storage. This shows the water level in the space 27 (Fig. 6). These figures will be explained below.

When the stored gas G is stored in the container body 12 at t+t+ (Fig. 4), the external force Pr acting on the bedrock 1 and the groundwater pressure Pw (stored groundwater level Wl) also rise accordingly (Fig. 5). Fig. 6).

Furthermore, when the stored gas G is sealed in the container body 12 under high pressure from t1 to t (Fig. 4), the internal pressure pg is supported by the rock mass 1, so the external force Pr acting on the rock mass 1 is the same. (Fig. 5), but the container body 12
Since the groundwater contained in the stress transmission layer 14 (wall 18) on the back side of the container body is discharged from the back side of the container body through the water conduit 25, the groundwater pressure Pw on the back side of the container body 12 remains almost constant. It is maintained (Figure 6) and does not rise above a certain value. At this time, as mentioned above, if the groundwater level W1 in the water storage space 27 exceeds the standard value, the stored water is discharged by the drainage means 28, and the groundwater pressure existing on the back side of the container body 12 is Pw is the minimum storage pressure P of storage gas G
g-may hold.

On the other hand, when the stored gas G is released at L, → t3, the internal pressure Pg of the container body 12 decreases (Fig. 4), and accordingly, the external force Pr acting on the rock l supporting this internal pressure also decreases ( Figure 5). At this time, in order to drain the groundwater that should be drawn back to the back side of the container body 12 to the drainage means, the groundwater pressure PW of the groundwater existing on the back side of the container body 12 is
This means that there is a decreasing trend (Figure 6).

After the entire specified amount of stored gas G is discharged, in a state where no receiving operation is performed (1, → 1.), the groundwater pressure Pw (stored groundwater level Wl) on the back side of the container body 12 is rising ( 6) is because groundwater from around the cavity 11 flows out to the back side of the container body 12. However, even in this case, the amount exceeding the reference value (Pg-min) is discharged by the groundwater regulating means 26 via the water conduit 25.

In this way, according to the rock tank 10, when high-pressure gas is stored, the container body 12 is deformed to support the storage pressure (internal pressure) on the rock 1 via the stress transmission layer 14, and the underground water pressure (external pressure) is ), a part of the groundwater was drained and adjusted from the back of the container body 12 to prevent excessive groundwater pressure from being applied to the container body 12.
There is no need to construct the container body from a thick steel plate or the like, so material costs and the like are significantly reduced, and a large-capacity storage tank can be constructed at low cost.

Moreover, unlike the water injection method described above, there is no need to determine the formation depth in consideration of the storage pressure, and high-pressure storage can be realized at a low depth, resulting in further cost reduction.

Furthermore, since the storage space and the bedrock are completely separated by the container body 12, the stored gas and groundwater do not come into direct contact with each other. It is also possible to reliably prevent such things as melting and infiltration.

Next, FIG. 7 shows a second embodiment of the present invention.

In this embodiment, the same components as in the first embodiment are given the same reference numerals.

In this embodiment, the container body 12 is made of a 2-bi steel plate that is much thinner than that of the previous embodiment, and furthermore, on the outer surface side (back side) of the container body 12, there are A buffer material 22 made of porous 1'1 material 1:1 is provided.The other structure is the same as that of the first embodiment.Therefore, the buffer material 22 is made of a porous 1'1 material 1:1. In this case, the sprayed concrete 13, the wall 18, and the buffer material 22 constitute a stress transmission layer 14.

In this case, the steel plate 2+' constituting the container body 12 has a thickness of several millimeters, and has a corrugated protrusion 21a extending in the longitudinal direction as shown in the figure.

The buffer material 22 is for uniformly transmitting the internal pressure transmitted through the thin steel plate 21' to the wall body 18.

According to the rock tank 10 according to the second embodiment, the steel plate 21' constituting the container body 12 is thinner than that of the first embodiment, and the amount of deformation of the container body 12 in response to external force is large, so that deformation is relatively small. It is effective when applied to easy bedrock 1. In other words, even if the rock mass l is easily deformed by external force, the container body 12 can follow it and deform, so that the storage pressure can be reliably supported by the rock mass l.

In the present invention, when the internal pressure decreases, groundwater pressure is discharged from the back side of the container body 12 to prevent external pressure from being applied to the container body 12 as much as possible. This is why the container body 12 is made of a thin material. This means that it can be configured.

Further, in this embodiment, since the material of the container body 12 is thinner, it is possible to further reduce the cost in terms of both material cost and manufacturing cost than that of the first embodiment.

In addition, in the embodiment, the groundwater adjustment means 26 is connected to the water storage space 2.
7 and drainage means 28, however, the groundwater regulating means according to the present invention is not limited to the one in the embodiments, and in short, the groundwater regulating means according to the present invention is capable of arbitrarily adjusting the groundwater pressure at the back surface of the container body 12. It would be good if it had a similar configuration. In addition, the above 2
In one embodiment, both the container body 12 and the steel plate 21 (2
1'), however, the structure of the container body 12 in the present invention is not necessarily limited to steel plates. For example, when the underground water pressure is approximately It is also possible to configure it with a sheet or the like.

〔Effect of the invention〕

As explained above, according to the method for storing high-pressure gas in the rock according to claim 1 of the present invention, when storing the high-pressure gas (at the time of receiving), the flexible structure container body is deformed to reduce the storage pressure (internal pressure) to the rock. In addition to supporting underground water pressure (external pressure), by draining and adjusting a portion of the groundwater from the back of the flexible structure container, excessive groundwater pressure will not be applied to the flexible structure container when releasing the stored gas. Since the container body does not need to be made of a thick steel plate or the like, the cost of materials is greatly reduced, and a large-capacity storage tank can be constructed at low cost. In addition, the construction depth can be set without being controlled by storage pressure or groundwater pressure, making it possible to realize high-pressure storage at a low depth.
- A reduction in the cost of the layer M is realized. Furthermore, since the storage space and the bedrock are completely separated by the container body 12,
The stored gas and the groundwater do not come into direct contact with each other, and therefore, leakage of the groundwater into the storage space or incorporation of the stored gas into the groundwater can be reliably prevented.

Further, according to the rock tank for high-pressure gas storage according to claim 2 of the present invention, the stress transmission layer transfers the stress generated in the flexible structure container body to the cavity wall surface without causing local stress concentration in the container body. The method described in claim 1 can be reliably realized, and the method described in claim 1 can be reliably realized. Accordingly, the above effects can be reliably achieved.

Furthermore, according to the high-pressure gas storage tank according to claim 3 of the present invention, the groundwater pressure adjusting means includes a water storage space formed in the bedrock, and a lJl water means for discharging the groundwater stored in this water storage space. Since it is configured as such, it is possible to efficiently adjust groundwater pressure by using the water storage space as a Hanover.
It can produce excellent effects such as

[Brief explanation of drawings]

Figures 1 to 3 show a practical example of the present invention; Figure 1 is a front sectional view of a rock tank for storing high-pressure gas;
The figure is a side view, FIG. 3 is an enlarged perspective sectional view of a part of the rock tank for high-pressure gas storage according to this embodiment, and FIG.
Figures 6 to 6 explain the operation of the rock tank for high-pressure gas storage according to the present invention. Figure 4 is a diagram showing changes in storage pressure during storage and release of stored gas, and Figure 5 is a diagram showing changes in storage pressure during storage and release of stored gas. Similarly, FIG. 6 is a diagram showing changes in external force acting on the rock cavity, FIG. 6 is a diagram showing changes in groundwater pressure and water level in the water storage space, and FIG. 7 is a diagram showing changes in the external force acting on the rock cavity. FIG. 8 is an enlarged perspective sectional view of a part of the storage rock tank, and is a schematic configuration diagram illustrating the concept of a water-sealing type in-rock storage facility that has already been provided. Storage gas, 1...Bedrock, wall surface,...Rock tank for high-pressure gas storage, -Cavity...Container body (flexible structure container body), Stress transmission layer, 25...Conduit, underground water pressure Adjustment means, ・Water storage space, 28... Drainage means. G... a 0 1 l ・ 12 ・ 14 ・ ・ 26 ・ 7

Claims (1)

[Claims] 1) When storing high-pressure gas in a rock, a flexible structure container body that is airtight and allows deformation against external forces is provided in a cavity formed in the rock; Storage of high-pressure gas in rock, characterized in that the stored gas is sealed inside the structural container, and the groundwater pressure existing on the back side of the flexible structural container is adjusted according to the internal pressure of the flexible structural container. Method. 2) A tank constructed in rock for storing high-pressure gas, in which a flexible structure container body that is airtight and allows deformation in response to external pressure is placed inside a cavity formed in the rock. A stress transmission layer having water permeability is provided between the wall surface constituting the cavity, and the stress transmission layer is communicated with underground water pressure adjustment means through a water conduit. Rock tank for high pressure gas storage. 3) The underground water pressure adjustment means is characterized by comprising a water storage space provided in the rock mass separately from the cavity, and a drainage means for discharging the groundwater stored in the water storage space. The rock tank for high pressure gas storage according to claim 2.