JP2002126437A - Device for recovering mixed gas - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mixed gas recovering device excellent for removing SF6 gas remaining in the gas to be discharged to the atmosphere so as to reduce the volume of the SF6 gas to be discharged. SOLUTION: A gas separating unit 1 is connected to a gas recovery and storage tank 2 for recovering the SF6 gas by interposing a valve B2 and also to a gas discharging unit 3 for discharging the gas from the unit 1 by interposing a valve B1. An adsorption unit 4 is connected to the gas outlet side of the unit 3 for taking the gas discharged from the unit 3 in the unit 4. An adsorbent consisting of synthetic zeolite is enclosed in the unit 4 so that the SF6 gas remaining in the taken-in gas is adsorbed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas recovery device for recovering an insulating gas from a gas insulating device, and more particularly to a gas recovery device.
The present invention relates to a mixed gas recovery device for separating and recovering SF6 gas from a mixed gas containing 6 gases.

[0002]

2. Description of the Related Art Generally, SF6 gas has excellent insulating performance and arc extinguishing performance, and is chemically stable and harmless gas. Therefore, it is widely used as an insulating gas to be filled in a circuit breaker, disconnector, or the like, which is collectively called a gas insulated switchgear (GIS). However, SF6 gas has a high greenhouse effect and a long life until decomposition. For this reason, from the viewpoint of global environmental protection, it was designated as a target of emission control at the 1997 Kyoto Conference on Global Warming (COP3). In the future, it is required that the emission of SF6 gas be reduced as much as possible in consideration of the long-term global environment. In order to meet this demand, various methods have been considered, such as downsizing of equipment and conversion to other gases, and among them, the mixed gas insulation method has attracted high interest. The mixed gas insulation method is a method in which a small amount of SF6 gas is added to a base gas such as nitrogen gas to form a mixed gas, which is used as an insulating gas. According to this method, the amount of use of SF6 gas itself can be reduced.
It is extremely effective in reducing the emission of 6 gases.

[0003] When performing maintenance or the like of a gas insulated device, it is essential to recover the insulating gas from the device. At this time, the collected gas is generally liquefied and stored for the purpose of obtaining high storage efficiency. In a mixed gas insulation type gas insulated apparatus, a target to be recovered is a mixed gas. However, in the case of a mixed gas containing SF6 gas and nitrogen gas simultaneously, there is a problem that it is difficult to liquefy as it is. Therefore, in a device for recovering a mixed gas, the mixed gas is usually separated into SF6 gas and nitrogen gas, only the SF6 gas is liquefied and stored, and the nitrogen gas is discharged into the atmosphere.

[0004] As such a mixed gas recovery apparatus, the present applicant has already filed Japanese Patent Application Nos. Hei 10-232640 and Hei 11 (1999).
No. 078588 is proposed. In these mixed gas recovery devices, the fundamental principle is a special molecular sieving effect of the adsorbent, and a pressure swing adsorption method is employed in which the adsorption power and the discharge power are increased by adjusting the gas pressure. According to these mixed gas recovery devices, the SF6 gas can be continuously separated from the mixed gas, and the SF6 gas can be liquefied and recovered.

A polymer separation membrane is also known as a means for separating SF6 gas from a mixed gas. The separation membrane is formed by bundling a large number of hollow fibers of polyimide. This conventional example utilizes the fact that the permeation speed when passing through a separation membrane differs depending on the gas. That is, since the SF6 gas has a low permeation rate, it can be captured inside the hollow fiber of the separation membrane. On the other hand, since nitrogen gas has a relatively high permeation rate and passes through the separation membrane, nitrogen gas can be discharged to the atmosphere as it is.

[0006]

However, the above-mentioned prior art has the following problems. That is,
It is extremely difficult to completely separate the SF6 gas from the mixed gas in the above-mentioned conventional example, whether using the special molecular sieving effect of the adsorbent and the pressure swing adsorption method, or using the polymer separation membrane. Met. Therefore, a small amount of SF6 gas is contained in the exhaust gas after the SF6 gas is separated and removed.
Gas remained. Therefore, if the exhaust gas is directly discharged into the atmosphere, the SF6 gas is discharged.

The present invention has been proposed to solve the above-mentioned problems, and an object of the present invention is to remove SF6 gas remaining in exhaust gas to the atmosphere, thereby contributing to a reduction in SF6 gas emission. It is an object of the present invention to provide an excellent mixed gas recovery device capable of performing the above-mentioned operations.

[0008]

In order to achieve the above object, the present invention provides a method for converting a mixed gas comprising a plurality of types of insulating gases including SF6 gas into SF6 gas and exhaust gas discharged into the atmosphere. A mixed gas recovery device provided with a gas separation device for separation, and a recovery gas storage tank for recovering the separated SF6 gas is connected to the gas separation device, has the following technical features.

According to the first aspect of the present invention, the exhaust gas is taken into the gas separation device, and the sulfur remaining in the exhaust gas is removed.
An adsorption device for adsorbing F6 gas is connected. According to the first aspect of the present invention, since the adsorbing device adsorbs the SF6 gas remaining in the exhaust gas, the SF6 gas in the exhaust gas can be removed, and the discharge of the SF6 gas into the atmosphere can be reliably prevented. Is possible. This allows
This can contribute to a reduction in SF6 gas emission.

According to a second aspect of the present invention, in the mixed gas recovery apparatus according to the first aspect, an adsorbent is sealed in the adsorbing device except for near a gas inlet side and near a gas outlet side. I do. In the second aspect of the present invention, since the adsorbent does not exist near the gas inlet side and the gas outlet side of the adsorption device, the gas once flows in this portion and then flows. Therefore, the mixed gas can flow while uniformly diffusing in the adsorption device. As a result,
The adsorbent can come into contact with the mixed gas over a wide area, and can adsorb SF6 gas efficiently.

According to a third aspect of the present invention, in the mixed gas recovery apparatus according to the second aspect, the adsorbent is made of a synthetic zeolite that selectively adsorbs SF6 gas. According to the third aspect of the present invention, by using a synthetic zeolite that selectively adsorbs SF6 gas as an adsorbent, the type of synthetic zeolite can be optimized, and the adsorption efficiency of SF6 gas is improved.

According to a fourth aspect of the present invention, in the mixed gas recovery apparatus according to any one of the first to third aspects, a pressure reducing device for reducing a pressure in the adsorption device is connected to the adsorption device. It is characterized by the following. According to the fourth aspect of the present invention, after the adsorbing device has been used for a predetermined time, the pressure in the adsorbing device is reduced by the depressurizing device.
F6 gas can be desorbed. Therefore, the adsorption device can be regenerated, and continuous use is possible. In addition, the service life of the adsorption device can be extended by periodically desorbing the SF6 gas from the adsorption device.

According to a fifth aspect of the present invention, in the mixed gas recovery apparatus of the fourth aspect, a nitrogen gas introducing device for introducing nitrogen gas into the adsorption device is connected to the adsorption device. . According to the fifth aspect of the present invention, the nitrogen gas introducing device guides the nitrogen gas into the adsorption device, whereby the SF6 gas desorbed from the adsorption device can be quickly pushed out of the device. Therefore, the time required for regeneration of the adsorption device can be reduced.

The invention according to claim 6 is the invention according to claim 4 or 5.
Wherein the SF6 gas desorbed from the adsorption device is guided into the gas separation device. According to the sixth aspect of the present invention, the SF6 gas desorbed from the adsorption device is guided into the gas separation device, so that the SF6 gas can be prevented from being scattered into the atmosphere, and environmental harmony is improved.

According to a seventh aspect of the present invention, in the mixed gas recovery device according to any one of the fourth to sixth aspects, the adsorption device is provided with a temperature control device for adjusting the temperature in the adsorption device. , The temperature controller is SF6
When adsorbing a gas, the temperature in the adsorption device is set to room temperature or lower than room temperature, and when desorbing SF6 gas from the adsorption device, the temperature in the adsorption device is set higher than room temperature. Features. In the above invention, when the adsorbing device adsorbs SF6 gas, the temperature in the adsorbing device is lowered to room temperature or lower than room temperature by the temperature control device, so that the SF6 gas is easily adsorbed, and The ability to adsorb SF6 gas is improved. On the other hand, when the SF6 gas is desorbed from the adsorption device, the temperature in the adsorption device is made higher than room temperature by the temperature control device, so that the SF6 gas is easily desorbed and the time required for regeneration of the adsorption device is shortened. And the collection efficiency of the mixed gas is increased.

According to an eighth aspect of the present invention, in the mixed gas recovery apparatus according to any one of the fourth to seventh aspects, the adsorption devices are installed in multiple stages, and the plurality of adsorption devices are S
It is characterized in that it can be switched to be connected in series when F6 gas is adsorbed and to be connected in parallel when SF6 gas is desorbed. According to the eighth aspect of the present invention, when the SF6 gas is adsorbed, a plurality of adsorbers are connected in series to increase the residence time of the exhaust gas in the adsorber, thereby improving the SF6 gas adsorption efficiency. In addition, when the SF6 gas is desorbed, the desorbed SF6 gas can be discharged from the adsorption device in a short time by arranging a plurality of adsorption devices in parallel. Therefore, the regeneration efficiency of the adsorption device is improved, and the gas recovery rate is increased.

According to a ninth aspect of the present invention, in the mixed gas recovery apparatus according to any one of the fourth to eighth aspects, the adsorption devices are provided in multiple stages, and each adsorption device is configured to adsorb and desorb SF6 gas. Is performed independently. According to the ninth aspect of the present invention, S
Since the adsorption and desorption of the F6 gas can be performed simultaneously in parallel, the improvement of the adsorption efficiency of the residual SF6 gas in the exhaust gas and the easy regeneration of the adsorption performance can be realized at the same time, and the processing speed of the mixed gas can be reduced Can be raised.

According to a tenth aspect of the present invention, in the mixed gas recovery apparatus according to any one of the first to ninth aspects, a gas detector for detecting SF6 gas is attached to the adsorption device. And According to the tenth aspect of the present invention, it is possible to obtain information on the gas configuration detected by the gas detector, so that it is possible to accurately change the operation of the adsorption device and the connection configuration. Therefore, S
Recovery of F6 gas can be performed reliably and quickly.

According to an eleventh aspect of the present invention, in the mixed gas recovery apparatus according to the tenth aspect, the gas detector detects the SF6 gas by sensing a halogen element or changing the thermal conductivity or absorbance of the gas. It is characterized by comprising. According to the eleventh aspect of the present invention, the SF
The change in the gas composition in the adsorption device can be accurately detected based on the sensing of the halogen element constituting the six gases or the change in the thermal conductivity of the gas or the absorbance of the gas.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (1) First Embodiment [Configuration] An example of an embodiment of the present invention will be described below.
This will be specifically described with reference to the drawings. The first embodiment corresponds to the first, tenth, and eleventh aspects of the present invention, and FIG. 1 is a configuration diagram of the first embodiment. The first embodiment is a mixed gas recovery device used in connection with a gas insulated switchgear 6 filled with a mixed gas comprising SF6 gas and nitrogen gas. The gas separating device 1 is connected to the gas insulated switchgear 6. The gas separation device 1 is a pressure swing adsorption device employing a pressure swing adsorption method,
The mixed gas is taken in from the gas insulated switchgear 6 to selectively adsorb only the nitrogen gas, thereby separating the mixed gas into SF6 gas and nitrogen gas. In addition,
The gas separation device 1 may be a separation device using a polymer separation membrane.

The gas separator 1 is connected to the gas separator 1 via a valve B2.
The recovered gas storage tank 2 for recovering the F6 gas has a valve B
Gas discharge devices 3 for discharging the exhaust gas from the gas separation device 1 through the gas separation device 1 are connected to each other. Further, an adsorbing device 4 for taking in exhaust gas from the gas discharging device 3 is connected to a gas outlet side of the gas discharging device 3. An adsorbent made of synthetic zeolite is sealed in the adsorber 4, and is configured to adsorb SF6 gas remaining in the exhaust gas taken in. These components are appropriately connected by a pipe 5. The control device 7 is connected to the valves B1 and B2. The control device 7 includes valves B1 and B
2 to control the gas flow path. Further, a gas detector 15 is attached to the gas outlet side of the adsorption device 4. This gas detector 15 is S
The sensor detects the halogen element contained in the F6 gas, and is connected to the control device 7.

[Operation and Effect] The operation of the first embodiment having the above configuration is as follows. First, valve B
1 and B2 are both closed, and the mixed gas flows from the gas insulated switchgear 6 to the gas separator 1. The gas separation device 1 separates the mixed gas into SF6 gas and nitrogen gas by selectively adsorbing only nitrogen gas by a pressure swing adsorption method. Since the amount of nitrogen gas adsorbed by the gas separation device 1 is limited, the valve B2 is opened after a predetermined time has elapsed, that is, when the adsorption force is still remaining, and the gas separation device 1 does not adsorb the nitrogen gas. The recovered SF6 gas is sent to the recovery gas storage tank 2 to liquefy and recover the SF6 gas. And
The valve B2 is closed when the nitrogen gas starts flowing through the valve B2. Next, with the valve B1 opened, the nitrogen gas adsorbed by the gas separation device 1 is desorbed by the gas discharge device 3 and sent to the adsorption device 4 at a constant flow rate. A small amount of SF6 gas remains in the nitrogen gas sent to the adsorption device 4. In the adsorption device 4, the adsorbent contains sulfur remaining in the nitrogen gas.
Adsorb F6 gas. Finally, only the nitrogen gas from which the SF6 gas has been removed is released to the atmosphere.

Further, in the first embodiment, the gas detector 15 detects the halogen element of the SF6 gas, detects a change in the composition of the SF6 gas and the nitrogen gas of the exhaust gas, and sends the information to the control device 7. Tell Therefore, since information about the gas composition is entered on-time, SF6 gas separation from the mixed gas can be performed more precisely than simply controlling the flow of the mixed gas by time. According to the first embodiment, since the SF6 gas slightly remaining in the nitrogen gas is removed by the adsorption device 4, it is possible to reliably prevent the SF6 gas from being discharged into the atmosphere. This can contribute to a reduction in SF6 gas emission.

(2) Second Embodiment [Configuration] A second embodiment corresponding to the second and third aspects of the present invention will be described with reference to FIG. The second embodiment is characterized in that the adsorption device 4 is constituted by an adsorption tube 8 in which an adsorbent 8a made of synthetic zeolite is sealed. As shown in FIG. 2, a partition plate 9 is attached near the inlet and outlet of the gas in the adsorption column 8. The partition plate 9 is provided with a hole through which the adsorbent 8a cannot pass, and the adsorbent 8a is sealed in a space sandwiched between the opposing partition plates 9. That is, the adsorption cylinder 8 has a structure in which there is no adsorbent 8a near the gas inlet side and near the gas outlet side. The shape of the adsorption cylinder 8 includes a polygonal prism such as a triangular prism, a quadrangular prism, and a pentagonal prism, a circular cylinder, and a sphere.

The synthetic zeolite constituting the adsorbent 8a is a general term for a group of hydrous aluminosilicate minerals, and has the general formula MeO.Al
Indicated by 2O3.mSiO2.nH2O. In the second embodiment, a spherical synthetic zeolite having pores of 10 angstroms on the surface is used. In synthetic zeolites, only molecules smaller than the uniform pores formed on the surface are adsorbed into the cavity through the pores. Therefore, excellent selective adsorptivity (molecular sieve effect) can be exhibited. Synthetic zeolites contain metal cations in the crystal structure, which act to attract polar groups electrostatically or polarize and attract polarizable molecules, and can be applied to the adsorption of neutral molecules. There are advantages. In addition, various types of synthetic zeolites are commercially available, such as spherical and cylindrical.

[Operation and Effect] In the second embodiment as described above, since the adsorbent 8a does not exist near the gas inlet side and the gas outlet side of the adsorption cylinder 8, the gas temporarily stays in this part. Later, the mixed gas flows into the adsorption column 8. Therefore, the mixed gas can flow while diffusing uniformly in the adsorption column 8, and the adsorbent 8a comes into contact with the mixed gas in a wide area. Therefore, the adsorbent 8a is SF
Six gases can be efficiently adsorbed.

The adsorbing power of the adsorbent 8a, which is a synthetic zeolite of 10 angstroms type, is nitrogen gas> SF6 gas in the case of nitrogen gas and SF6 gas.
SF6 gas can be selectively adsorbed from a mixed gas of nitrogen and SF6. For example, a change in SF6 gas concentration when a mixed gas of nitrogen gas and SF6 gas containing 5% SF6 gas is sealed at a pressure of 0.2 MPa in a 2850 mL capacity tank and a 10 Å synthetic zeolite is placed in the tank. 3 is shown. As is apparent from this figure, the SF6 gas concentration in the tank decreases with the passage of time, and only the SF6 gas is selectively adsorbed on the synthetic zeolite.

According to the second embodiment, by using synthetic zeolite as the adsorbent 8a, only SF6 gas can be selectively adsorbed from a mixed gas of nitrogen gas and SF6 gas. Therefore, the recovery efficiency of SF6 gas is improved, and the amount of SF6 gas released to the atmosphere is reduced to a negligible level. In the second embodiment, a synthetic zeolite of 10 Å type is used. However, the same effect can be obtained by using a spherical synthetic zeolite having pores of 9 Å on the surface.

(3) Third Embodiment [Configuration] The third embodiment includes the inventions according to claims 4 to 7, and as shown in FIG. On the side, a pressure reducing device 10 for reducing the pressure in the adsorption device 4 is connected via valves B5. The decompression device 10 is connected to a mixed gas introduction unit recovery tank 11 for temporarily storing the gas discharged from the adsorption device 4. Although not shown, the gas separation device 1 is connected to the mixed gas introduction section recovery tank 11. Further, a nitrogen gas introducing device 12 for guiding nitrogen gas into the adsorption device 4 via a valve B6 is connected to a gas outlet side of the adsorption device 4. The nitrogen gas fed into the adsorption device 4 by the nitrogen gas introduction device 12 may be any one of exhaust gas after removing SF6 gas by the adsorption device 4, nitrogen gas previously sealed in a gas cylinder, and nitrogen separated from air. Or use.

Further, the adsorption device 4 is provided with an electric heater 14 for adjusting the temperature inside the adsorption device 4. The electric heater 14 is configured as follows. That is,
When the adsorption device 4 adsorbs SF6 gas, the temperature in the adsorption device 4 is set to room temperature or lower than room temperature, and when the SF6 gas is desorbed from the adsorption device 4, the temperature in the adsorption device 4 is set higher than room temperature. It is configured. In addition, as a device for adjusting the temperature in the adsorption device 4, a device in which an adsorption tube is placed in a thermostat, a device in which steam gas is blown into the adsorption tube, a device in which a heat source such as a heating wire is put in the adsorption tube, and a cooling device And the like.

[Operation and Effect] The operation and effect of the third embodiment as described above are as follows. That is, the valve B
3, B4 is opened, valves B5 and B6 are closed,
The exhaust gas is sent from the gas discharge device 3 to the adsorption device 4. As the adsorbent in the adsorption device 4 adsorbs the SF6 gas remaining in the exhaust gas, the adsorption amount of the adsorbent approaches saturation, and the adsorption capacity of the adsorption device 4 decreases. Then, valve B
3 and B4 are switched to the closed state, and the valve B5 is opened. However, the valve B6 maintains the closed state. Then, a pressure reducing operation is performed by the pressure reducing device 10 to reduce the pressure in the adsorption device 4. Thereby, SF6 gas is desorbed from the adsorbent.
At this time, the valve B6 is opened at predetermined intervals, nitrogen gas flows from the nitrogen gas introduction device 12 into the adsorption device 4, and the SF6 gas desorbed in the adsorption device 4 is pushed out of the adsorption device 4. Can be.

In addition, the direction in which the nitrogen gas flows out of the adsorption device 4 due to the reduced pressure and the direction in which the nitrogen gas flows into the adsorption device 4 are the same, but the direction in which the exhaust gas flows into the adsorption device 4 by the gas exhaust device 3. The direction in which the nitrogen gas flows out of the adsorption device 4 due to the reduced pressure and the direction in which the nitrogen gas flows into the adsorption device 4 are opposite to the direction in which the exhaust gas flows into the adsorption device 4 by the gas discharge device 3. Therefore, the SF6 gas adsorbed by the adsorption device 4 can be efficiently desorbed. Next, the adsorption device 4 containing the desorbed SF6 gas
The inside gas is sent to the mixed gas introduction section recovery tank 11. Once the gas stored in the mixed gas introduction section recovery tank 11 is sent to the gas separation device 1 shown in FIG. 1, the gas separation device 1 separates and recovers SF6 gas together with the mixed gas from the gas insulated switchgear 6. .

In the third embodiment as described above, the depressurizing operation of the depressurizing device 10 can re-activate the adsorbing power of the adsorbing device 4 in which the adsorbing capacity of the adsorbing device 4 has decreased due to the adsorption of SF6 gas. Therefore, the adsorption device 4 can be regenerated and can be used continuously. In addition, the service life of the adsorption device 4 can be extended by periodically performing the desorption of the SF 6 gas from the adsorption device 4. Further, by flowing the nitrogen gas into the adsorption device 4 by the nitrogen gas introduction device 12, the time required for reactivating the adsorption force of the adsorption device 4 can be reduced. Therefore, it is possible to efficiently remove the SF6 gas from the exhaust gas. In addition, S from the adsorbent generated when the adsorption device 4 is reactivated.
The F6 gas can be recovered by the gas separation device 1 via the mixed gas introduction section recovery tank 11. Therefore, there is no possibility that SF6 gas is scattered in the atmosphere, the environmental harmony is high, and the environment is more advantageous.

Incidentally, it is known that the adsorption capacity of the synthetic zeolite constituting the adsorbent in the adsorption device 4 changes with temperature. In general, synthetic zeolites have a temperature characteristic that the adsorption capacity increases at low temperatures and decreases at high temperatures. In other words, the relationship between the amount of SF6 gas adsorbed on the synthetic zeolite and the temperature is inversely proportional. For example, a 10 angstrom type synthetic zeolite has a temperature characteristic as shown in FIG. 5 when a mixed gas of nitrogen and SF6 containing 5% SF6 is sealed in a tank with a capacity of 2850 mL at a pressure of 0.2 MPa.

That is, in the third embodiment, when the adsorbing device 4 adsorbs SF6 gas, the temperature in the adsorbing device 4 is set to room temperature or lower than room temperature by the electric heater 14, so that the SF6 gas is easily adsorbed. are doing. Therefore, the adsorption capacity of the adsorption device 4 for the SF6 gas in the exhaust gas is improved. On the other hand, when desorbing the SF6 gas from the adsorption device 4, the temperature inside the adsorption device 4 is made higher than room temperature by the electric heater 14, so that the SF6 gas is easily desorbed. Thereby, the time required for regeneration of the adsorption device 4 can be shortened, and as a result, the efficiency of recovering the mixed gas can be increased.

(4) Fourth Embodiment [Configuration] A fourth embodiment corresponding to the eighth aspect of the present invention will be described with reference to FIG. That is, the adsorption device 4 is constituted by five adsorption cylinders 8 or adsorption cylinders 8 divided into five, and a three-way solenoid valve 13 is connected to each adsorption cylinder 8 by the pipe 5. When the adsorption device 4 adsorbs the SF6 gas in the exhaust gas, the three-way solenoid valve 1
By connecting two directions by three, five adsorption cylinders 8 are connected in series, and when the adsorption device 4 desorbs SF6 gas, three directions are connected by a three-way solenoid valve 13 to connect five directions. Are connected in parallel.

[Effects] In the fourth embodiment described above, when SF6 gas is adsorbed, the exhaust gas residence time in the adsorber 4 is increased by connecting five adsorbers 4 in series. Therefore, the adsorption efficiency of SF6 gas can be improved. In addition, when the SF6 gas is desorbed, five adsorbing devices 4 are arranged in parallel so that the desorbed SF6 gas can be adsorbed by the adsorbing device
In a short time. Therefore, the regeneration time of the adsorption device 4 can be shortened, and as a result, the gas recovery rate improves.

(5) Fifth Embodiment [Configuration] The fifth embodiment corresponds to the invention described in claim 9, and FIG. 7 is a configuration diagram of the fifth embodiment. As shown in FIG.
Adsorption devices 41 and 42 are installed via 7, B10. Each of the adsorption devices 41 and 42 is configured to independently adsorb and desorb SF6 gas. Further, the decompression device 1 is connected to the adsorption devices 41 and 42 via valves B8 and B11.
0 is connected. Further, valves B9 and B12 are connected to the adsorption devices 41 and 42, respectively.

[Operation and Effect] The operation of the fifth embodiment having the above configuration is as follows. First, B7, B
9, B11 is opened and B8, B10, B12 are closed, and the exhaust gas is sent to the adsorption device 41 by the gas exhaust device 3 to adsorb and remove a small amount of SF6 gas remaining in the exhaust gas before passing through the valve B9. To release only nitrogen gas to the atmosphere. Next, if the adsorption and removal of the SF6 gas is continued, the adsorption capacity of the adsorption device 41 is reduced, so that the valve B7,
With B9 and B11 closed and valves B8, B10 and B12 open, the exhaust gas from the gas discharge device 3 is sent to the adsorption device 42 whose adsorption capacity has been restored. At the same time, the adsorption device 41 performs a decompression operation by the decompression device 10 to reactivate it, and recovers the adsorption capability of the adsorption device 41. Also,
When the adsorption capacity of the adsorption device 42 is reduced, the above operation is reversed, and thereafter, these operations are repeatedly performed. According to the fifth embodiment described above, it becomes possible to simultaneously remove and remove the SF6 gas remaining in the exhaust gas by the adsorption device 4 and reactivate the adsorption force of the adsorption device 4 in parallel. The processing speed of the mixed gas is increased.

(6) Other Embodiments The present invention is not limited to the above embodiments. For example, another embodiment corresponding to the invention described in claim 8 will be described with reference to FIG. In this embodiment, seven suction cylinders C1 to C7 are connected in series by a pipe 5, and the connection portion can be detached and attached with one touch. As shown in FIG. 8A, the gas from the gas discharge device 3 is sent to the adsorption column C1, and the adsorption columns C2, C3, C
4 and C5, the residual S in the exhaust gas
F6 gas can be adsorbed and removed.

Next, when the adsorption and removal of the SF6 gas is continued, the SF6 gas is successively adsorbed from the first adsorption cylinder C1, and starts to decrease from the adsorption capacity of the adsorption cylinder C1. Therefore, before the SF6 gas that could not be adsorbed and removed by the last adsorption cylinder C7 is discharged, the adsorption cylinder C1 is removed as shown in FIG. Connect to the discharge device 3. In the removed adsorption cylinder C1, the SF6 gas is desorbed by the decompression device 10 to re-activate the adsorption force, as in the above embodiment. In addition, since the adsorption | suction cylinder C1 is once removed, quick reactivation in a high temperature state is possible. After the suction force of the suction tube C1 returns, the suction tube C1 enters a standby state, and is connected to the last suction tube when another suction tube is removed. Since then
Such an operation is repeatedly performed in order.

According to the above-described embodiment, the SF6 gas can be efficiently adsorbed by sequentially moving up the arrangement of the adsorption cylinders, and the gas recovery efficiency can be greatly increased. The removed adsorption cylinder can be stored as it is, without performing the operation of desorbing the SF6 gas by the decompression device 10, so that the adsorbed SF6 gas does not leak from the adsorption cylinder.

Another embodiment corresponding to the ninth aspect of the present invention will be described with reference to FIG. Since the gas separation device 1 employs the pressure swing adsorption method, a plurality of adsorption tanks can be provided therein.
In the embodiment shown in FIG. 9, two adsorption tanks F1 and F2 are installed in the gas separation device 1. Each adsorption tank F1, F2
Are connected to gas discharge devices 31, 32, respectively, and the gas discharge devices 31, 32 are connected to adsorption devices 41, 42 via valves B13, B14. Further, the suction devices 41 and 42 are connected to the suction devices 4 via valves B9 and B12.
3 are connected.

In the embodiment having the above-described configuration, when the gas pressure in the adsorption tank F1 in the gas separation device 1 is reduced to discharge the exhaust gas from the gas separation device 1, the gas discharge device 31 connects the gas discharge device 31 in series. The exhaust gas is sent to the connected adsorbers 41 and 43, and the adsorbers 41 and 43 remove the residual SF6 gas in the exhaust gas and discharge it to the atmosphere. At the same time, when the gas pressure in the adsorption tank F2 is increased to separate the mixed gas, the operation of the pressure reducing device 10 connected to the adsorption device 42 causes the adsorption device 42 to reactivate the adsorption force. I have.

Next, the operation of the adsorption tank F1 and the operation of the adsorption tank F2 are switched. When the gas pressure in the adsorption tank F1 is increased accordingly, the decompression device 1 connected to the adsorption device 41
By the action of 0, the adsorption force of the adsorption device 41 is reactivated. When the gas pressure in the adsorption tank F2 is lowered, the adsorption devices 4 connected in series by the gas discharge device 32 are connected.
The exhaust gas is sent to the exhaust gas 2, 43, and the residual SF6 gas in the exhaust gas is removed by the adsorption devices 42, 43 and released to the atmosphere.
Thereafter, the above operation is repeated. Also, the suction device 43
In the case where the adsorption capacity is reduced, the pressure is appropriately reduced according to the above embodiment, and the adsorption power can be reactivated. Note that a plurality of the suction devices 43 may be used and connected in series. Also in the above embodiment, the suction device 4
The removal of the SF6 gas remaining in the exhaust gas by the exhaust gases 1, 42, and 43 and the reactivation of the adsorptive power of the adsorption devices 41, 42, and 43 can be performed simultaneously, thereby increasing the processing speed of the mixed gas. be able to. Further, since the adsorption devices 41, 42, 43 can be regenerated according to the pressure change in the adsorption tanks F1, F2 of the gas separation device 1 by the pressure swing adsorption method, the adsorption power of the adsorption devices 41, 42, 43 can be obtained. The frequency of the decompression operation to reactivate can be increased,
More reliable reactivation is possible.

Also, the number of adsorption cylinders and adsorption devices can be appropriately changed, and in the embodiments corresponding to the eighth and ninth aspects of the present invention, if there are multiple stages, the adsorption efficiency of the residual SF6 gas in the exhaust gas can be improved. And the regeneration of the adsorption performance can be facilitated. In addition to the detection principle of the halogen element as a gas detector, for example, the detection principle is based on the difference in thermal conductivity of the gas, and the detection principle is based on the change in the absorbance of the gas. There may be.

[0047]

As described above, according to the mixed gas recovery apparatus of the present invention, the exhaust gas is taken in from the gas separation apparatus, and the adsorber for adsorbing the residual SF6 gas in the exhaust gas is provided. In addition, it is possible to remove the SF6 gas remaining in the exhaust gas, thereby contributing to a reduction in SF6 gas emission.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a first embodiment of the present invention.

FIG. 2 is a sectional view of a main part according to a second embodiment of the present invention.

FIG. 3 is a graph showing that the synthetic zeolite reduces the SF6 gas concentration in the second embodiment of the present invention.

FIG. 4 is a configuration diagram of a third embodiment of the present invention.

FIG. 5 is a graph showing temperature characteristics of a synthetic zeolite according to the third embodiment of the present invention.

FIG. 6 is a configuration diagram of a fourth embodiment of the present invention.

FIG. 7 is a configuration diagram according to a fifth embodiment of the present invention.

FIG. 8 is a configuration diagram of another embodiment of the present invention.

FIG. 9 is a configuration diagram of another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Gas separation device 2 ... Recovered gas storage tank 3, 31, 32 ... Gas discharge device 4, 41, 42, 43 ... Adsorption device 5 ... Piping 6 ... Gas insulated switchgear 7 ... Control device 8 ... Adsorption cylinder 8a ... Adsorption Agent 9 ... Partition plate 10 ... Decompression device 11 ... Nitrogen gas introduction device 12 ... Mixed gas introduction part recovery tank 13 ... Three-way solenoid valve 14 ... Electric heater 15 ... Gas detector

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiromi Naozuka 2-1 Ukishima-cho, Kawasaki-ku, Kawasaki-shi, Kanagawa Prefecture Inside the Toshiba Hamakawasaki Plant (72) Inventor Hiroshi Murase 2, Ukishima-cho, Kawasaki-ku, Kawasaki-shi, Kanagawa No. 1 F-term in Toshiba Hamakawasaki Plant (reference) 4D012 CA20 CB14 CD05 CE01 CF04 CF08 CG01 CH06 CH08 CJ02 5G017 DD07 DD11 5G028 GG05

Claims (11)

[Claims] 1. A gas separation device for separating a mixed gas comprising a plurality of types of insulating gases including SF6 gas into SF6 gas and exhaust gas discharged into the atmosphere is provided, and the gas separation device separates the mixed gas. In a mixed gas recovery device to which a recovery gas storage tank for recovering SF6 gas is connected, an adsorber for taking in the exhaust gas and adsorbing the SF6 gas remaining in the exhaust gas is connected to the gas separation device. Characteristic mixed gas recovery device. 2. The mixed gas recovery device according to claim 1, wherein an adsorbent is sealed in the adsorption device except for a portion near a gas inlet side and a portion near a gas outlet side. 3. The mixed gas recovery device according to claim 2, wherein the adsorbent is composed of a synthetic zeolite that selectively adsorbs SF6 gas. 4. The apparatus according to claim 1, wherein a pressure reducing device for reducing a pressure in the suction device is connected to the suction device.
4. The mixed gas recovery device according to any one of items 1 to 3. 5. The mixed gas recovery device according to claim 4, wherein a nitrogen gas introducing device for introducing nitrogen gas into the adsorption device is connected to the adsorption device. 6. The mixed gas recovery device according to claim 4, wherein the SF6 gas desorbed from the adsorption device is configured to be guided into the gas separation device. 7. The adsorption device is provided with a temperature control device for adjusting the temperature in the adsorption device, and the temperature control device sets the temperature in the adsorption device to room temperature or when the adsorption device adsorbs SF6 gas. 7. The apparatus according to claim 4, wherein the temperature in the adsorption device is set to be lower than room temperature when the SF6 gas is desorbed from the adsorption device.
Item 5. The mixed gas recovery device according to the item 1. 8. The adsorber is installed in multiple stages, and the plurality of adsorbers are switchably connected in series when adsorbing SF6 gas and connected in parallel when desorbing SF6 gas. The mixed gas recovery device according to any one of claims 4 to 7, wherein: 9. The adsorption device according to claim 4, wherein the adsorption devices are provided in multiple stages, and each adsorption device is configured to independently adsorb and desorb SF6 gas.
Item 5. The mixed gas recovery device according to the item 1. 10. A gas detector for detecting SF6 gas is attached to the adsorption device.
The mixed gas recovery apparatus according to any one of claims 9 to 9. 11. The gas detector detects a halogen element or changes the thermal conductivity or absorbance of a gas.
The mixed gas recovery apparatus according to claim 10, wherein the apparatus is configured to detect six gases.