JP3864355B2 - Leakage detection method in high pressure storage facilities in bedrock - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a leak detection method in a high-pressure storage facility in a rock that is constructed for storing high-pressure gas (natural gas, propane, butane, hydrogen, helium, etc.).
[0002]
[Prior art]
A high-pressure gas storage facility (hereinafter simply referred to as a storage facility) for high-pressure gas is constructed by lining the inner surface of a cavity provided by excavating the rock.
[0003]
For storage facilities such as those mentioned above, measures against leakage of high-pressure gas stored inside are very important from the viewpoints of environmental protection and safety in facility operation. This is because if a high-pressure gas leaks, it not only significantly disturbs the surrounding environment of the area where the storage facility is provided, but also may cause an explosion of the storage facility.
[0004]
Conventionally, as a method of investigating the existence of leakage of high-pressure gas in the storage facility as described above, as in the case of a gas holder (gas storage container), it is directly inspected from outside the storage facility, A method for estimating leakage by calculation using a state equation from changes in pressure and temperature is employed.
[0005]
[Problems to be solved by the invention]
However, the gas holders are inspected from outside the storage facility, but the storage facilities built in the rock cannot directly inspect the steel lining from the outside like the gas holder, and the calculation method using the state equation is accurate. However, it has been pointed out that there are problems such as being low, and even if a result indicating leakage is obtained, it is impossible to specify the location of the leakage.
[0006]
The present invention has been made in view of the above circumstances, and for a high-pressure storage facility in bedrock intended for high-pressure gas, leakage of the high-pressure gas stored inside is accurately detected, and the leakage location It aims at providing the detection method of the leak in the high-pressure storage facility in the rock which can specify.
[0007]
[Means for Solving the Problems]
As means for solving the above-mentioned problems, first, an inspection tube provided with a flow path through which high-pressure gas can flow is provided in the tube wall so as to be in contact with the storage facility and filled with groundwater. A plurality of inspection tubes are arranged, and one inspection tube for performing a leakage inspection is opened by emptying the ground water filled therein and draining other inspection tubes. It is assumed to be filled with groundwater. If there is a leak in the bulkhead of the storage facility where the emptied test tube is attached, the high-pressure high-pressure gas leaking from the storage facility will gradually move into the low-pressure test tube over a period of time. It flows in. Thereafter, the gas in the evacuated test tube is collected, and the concentration of the high-pressure gas is measured with a measuring instrument such as gas chromatography. If the gas contains high-pressure gas or exceeds the standard value, it can be confirmed that there is a leak in the partition wall of the storage facility to which the previous test tube is attached.
In addition, after the above-described leakage detection for one inspection tube is completed, the same leakage detection is performed for all the other inspection tubes one by one. In other words, the inside of the inspection tube that has finished leak detection is filled with water, and after that, of the other test tubes that have not finished leak detection, one test tube is emptied by draining the groundwater filled therein. The test tube that has been opened and the other test tubes and the leak test have been completed should be filled with groundwater, left for an arbitrary period of time, and then the gas in the emptied test tube is collected to measure the concentration of natural gas. To detect leaks. By carrying out this leak detection for all the test tubes one by one, it is possible to limit the range in which the leak occurs to some extent.
[0008]
By the way, since the drainage pipe is arrange | positioned in the storage facility in order to drain the groundwater which flows in the bedrock in the construction stage, it is also possible to use this pipe as an inspection pipe.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of a leak detection method in a high pressure storage facility in a rock according to the present invention will be described with reference to FIGS.
1 is a so-called silo-type capsule having a circular bottom surface and a spherical upper portion, and is provided in the rock mass. It is built in the cavity 2. The cavity 2 is formed in a capsule shape in accordance with the outer shape of the storage facility 1.
[0010]
An outer shell 3 of filled concrete is formed on the entire inner wall surface of the cavity 2, and a thin steel plate lining 4 is stuck inside the outer shell 3 without a gap.
[0011]
As shown in FIG. 2, around the storage facility 1, a drain pipe (inspection pipe) 5 that takes in and drains groundwater flowing in the rock and prevents groundwater pressure from acting on the lining 4 is the surface of the outer shell 3. A plurality of storage facilities 1 are disposed between the top and bottom of the storage facility 1 in close contact with each other. These drainage pipes 5 extend radially from the top of the storage facility 1 along the upper spherical surface when viewed from above, and are disposed downward so as to surround the storage facility 1.
[0012]
As shown in FIG. 3, the pipe wall of the drain pipe 5 is provided with a number of holes (flow paths) 6 for taking in the ground water flowing through the rock, and the ground water flows into the drain pipe 5 through the holes 6. It is supposed to be.
[0013]
The upper ends of the drain pipes 5 are bundled independently at the top of the storage facility 1, and are provided on the bedrock located above the storage facility 1 through the guide shaft 7 excavated upward from the top. It extends to the upper access tunnel 8. A water supply facility (not shown) for supplying water to each drain pipe 5 is connected to the upper end of each drain pipe 5 reaching the upper access tunnel 8 via an upper valve 9. The upper valve 9 is individually installed in each drain pipe 5, the upper valve 9 is closed to close the upper end of the corresponding drain pipe 5, and the upper valve 9 is opened to open the drain pipe 5 in the atmosphere. It is supposed to be open to.
[0014]
On the other hand, the lower end of each drainage pipe 5 reaches the bottom of the storage facility 1 and passes through the lower plug 10 that closes the tunnel provided in the rock when the storage facility 1 is constructed while being independent of each other. It extends to the lower access tunnel 11 used. A drainage treatment facility (not shown) for treating groundwater flowing into each drainage pipe 5 is installed via a lower valve 12 at the lower end of each drainage pipe 5 reaching the lower access tunnel 11. The lower valve 12 is individually installed in each drain pipe 5.
[0015]
The storage facility 1 configured as described above is normally operated as follows.
First, at the stage of constructing the storage facility 1, the lower valve 12 of each drainage pipe 5 is opened, and groundwater that flows into the cavity 2 from the bedrock and impedes construction is allowed to flow into the drainage pipe 5 to drain the water. To do.
[0016]
In the state where the natural gas is stored inside after the storage facility 1 is completed, the internal pressure of the natural gas acts on the lining 4, and even if the underground water pressure acts on the lining 4 from the bedrock side, there is no particular problem. Since it is considered that the lining 4 is eroded by the circulation of the groundwater, the drainage pipes 5 are filled with the groundwater, and the upper and lower valves 9 and 12 are all closed, so that the groundwater does not flow. Like that.
[0017]
The natural gas leak inspection is carried out as follows.
First, for each of the drainage pipes 5 filled with groundwater, the lower valve 12 is opened to drain the groundwater filled in the interior. When the drainage becomes empty, the lower valve 12 is closed and the upper valve 9 is opened. Open the drain pipe to the atmosphere. If there is a leak in the lining 4 where the drainage pipe 5 is emptied, the high-pressure natural gas leaking from the storage facility 1 will become low pressure (atmospheric pressure) over time. It gradually flows into the drainage pipe 5.
[0018]
Thereafter, the air in the drainage pipe 5 that has been emptied is collected, and the concentration of natural gas in the collected air is measured using a measuring instrument such as gas chromatography. If natural gas is present in the collected air, or if it is contained above a certain value, it is determined that a leak has occurred in the lining 4 where the drain pipe 5 is attached.
[0019]
When the extraction inspection of the air in the drain pipe 5 is finished, water is supplied to the drain pipe 5 from the water supply facility installed in the upper access tunnel 8 and the drain pipe 5 is filled together with the groundwater flowing in from the rock side.
[0020]
The above inspection work is carried out for all drainage pipes 5 and the presence or absence of leakage is investigated for the lining 4 of each part to which each drainage pipe 5 is attached. Identify.
[0021]
If the natural gas leakage inspection of the storage facility is performed as described above, the inspection accuracy is higher than that of the conventional method performed by the gas holder by directly inspecting from the outside of the storage facility 1 close to the lining 4. Can be significantly improved.
[0022]
Since the air in the drain pipe 5 is sampled and the concentration of natural gas contained in the air is directly measured to determine the presence or absence of leaks, it is inspected only indirectly compared to the method using the conventional equation of state. Accuracy can be significantly improved.
[0023]
By inspecting each drain pipe 5 one by one, the range in which leakage occurs can be limited to some extent. This makes it easier to take measures such as repairs.
[0024]
Since the inspection is carried out using the equipment provided for groundwater drainage in advance, there is almost no need to provide the equipment for inspection in the storage facility, and the cost necessary for carrying out the inspection can be reduced. it can.
[0025]
In the above-described embodiment, the silo type storage facility has been described as an inspection target. However, the present invention is not limited to the silo type storage facility, and can be applied to an underground storage facility having other forms. Moreover, although the facility which stored the natural gas was demonstrated in this embodiment, this invention is not limited to this, It can implement also about the storage facility of various gas, such as propane, butane, hydrogen, helium.
[0026]
【The invention's effect】
As described above, according to the leak detection method in the high pressure storage facility in the rock according to the present invention, since the gas leakage is directly inspected from the outside of the storage facility, the inspection is compared with the method of inspecting from the inside of the storage facility. Accuracy can be significantly improved. In addition, the air inside the test tube is sampled and the concentration of the high-pressure gas contained in the air is directly measured to determine the presence or absence of leakage. The accuracy can be greatly improved. Further, by conducting an inspection on each of the inspection tubes arranged around the storage facility, it is possible to limit the extent of leakage to some extent. This makes it easier to take measures such as repairs.
[0027]
Further, according to the method for detecting leakage in a high-pressure storage facility in a rock according to the present invention, inspection is performed using equipment provided in advance for draining groundwater, so that equipment for inspection is provided in the storage facility. There is almost no need, and the cost required to carry out the inspection can be reduced.
[Brief description of the drawings]
FIG. 1 is a cross-sectional perspective view showing a high-pressure storage facility in a rock that implements a leakage detection method according to the present invention.
FIG. 2 is a vertical sectional view showing a high-pressure storage facility in a rock mass, similarly.
FIG. 3 is a cross-sectional perspective view of a main part showing a state of installation of a drain pipe.
[Explanation of symbols]
1 High pressure storage facility in bedrock 4 Lining 5 Drainage pipe (inspection pipe)
6 holes (flow path)
9 Upper valve 12 Lower valve

Claims (3)

A method for detecting leakage of high-pressure gas stored inside to a high-pressure gas storage facility built underground to store high-pressure gas,
A plurality of test tubes provided with a flow path through which high-pressure gas can flow in the tube wall in a state filled with groundwater therein so as to be in contact with and surround the high-pressure storage facility in the rock,
Among the plurality of test tubes, one test tube is emptied and opened by draining the groundwater filled therein, and the other test tubes are filled with groundwater,
A method for detecting a leak in a high pressure storage facility in a rock, wherein the leak is detected by collecting the gas in the test tube that has been left empty for an arbitrary period of time and measuring the concentration of natural gas. In the detection method of the leak in the high-pressure storage facility in the rock mass described in claim 1,
After finishing leak detection for the one test tube,
Fill the inside of the inspection tube that has completed leak detection with water, and then open and empty one of the other inspection tubes that have not completed leak detection by draining the groundwater filled inside. For other inspection tubes and inspection tubes that have completed leakage inspection, fill them with groundwater, leave them for an arbitrary period of time, collect the gas in the empty inspection tubes, and measure the concentration of natural gas. Detect leaks,
A method for detecting leakage in a high pressure storage facility in a rock, wherein this leakage detection is carried out for every single inspection tube . In the detection method of the leak in the high-pressure storage facility in the rock mass described in claim 1 or 2,
A method for detecting leakage in a high-pressure storage facility in a rock, wherein a drainage pipe disposed around the high-pressure storage facility in a rock is used as the inspection tube to drain groundwater flowing through the rock.

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