KR20120033472A - Recovery device of the insulation gas and system control method thereof - Google Patents

Abstract

PURPOSE: An apparatus for collecting insulation gas and a method for operating the same are provided to suppress the discharging of insulation gas into atmosphere and to compactize the apparatus. CONSTITUTION: An apparatus for collecting insulation gas includes a collecting part(102), a storing part(104), and a refining part(106). The collecting part is in connection with an insulating unit and collects and pressurizes SF_6. The storing part is in connection with the collecting part and liquefies and stores the collected SF_6. The refining part eliminates impurities from the SF_6 and feeds-back the SF_6 to the collecting part. The refining part includes hollow fiber membrane(126) and vacuum pressure swing adsorption(128). The hollow fiber membrane and the vacuum pressure swing adsorption are serially arranged with respect to the storing part.

Description

Recovery device of the insulation gas and system control method

The present invention relates to an insulation gas recovery apparatus and a method of operating the same, and more particularly, to a compact apparatus for recovering and purifying SF ₆ , which is insulation gas, from an instrument when repairing or inspecting insulation equipment using SF ₆ gas. It relates to its operation method. As a result, it is possible to suppress the release of SF _{6 into} the atmosphere during the refining process while supplying high-quality insulation gas to the insulation equipment.

Gas Insulated Switchgear (GIS), such as transmission and distribution equipment, uses insulation gas to suppress the contact resistance generated from the distribution switch. SF ₆ is widely used as insulation gas in transmission and distribution equipment because of its excellent insulation. However, SF ₆ must actively suppress its atmospheric emissions because its global warming factor (GWP) is 22,900 times higher than that of carbon dioxide.

Therefore, in the transmission and distribution equipment, in order to check and repair the transmission and distribution equipment due to aging of the switch, SF ₆ is recovered and stored in an external container so as to minimize the emission of SF _{6 in} the atmosphere, and then recovered again when the inspection is completed. The SF ₆ is charged in a power distribution unit.

Since the insulation efficiency is influenced by the purity of the insulation gas, it is necessary to maintain the concentration as high as possible (typically 97% by weight or more). Therefore, it is necessary to actively suppress air mixing during the diffusion of air into the insulating device or the movement of the insulating gas into the storage container, and maintain high concentration through purification.

Many researches have been conducted in this regard, and numerous literatures and patents are available.

First, an insulation gas recovery device 10 having a simple configuration as shown in FIG. 1 is known.

The insulator gas recovery device 10 has a compressor 22 directly connected to the insulator 1, a cooler 14 connected to the compressor 22, and a storage container 16 connected to the cooler 14. Connected. Therefore, after pressurizing SF ₆ supplied from the insulator 1 by the compressor 22 to a high pressure, the temperature is lowered through the cooler 14 to change SF ₆ into a liquid phase, and then the pressure vessel. The storage container 16 is to be stored.

Since the configuration uses a compressor, when the pressure in the insulator 1 is lowered to an atmospheric pressure level, it is no longer possible to inhale SF ₆ from the insulator 1. Therefore, SF ₆ in the insulator 1 cannot be completely removed, so that 80% of the gas (usually 5 bar) filled in the insulator 1 is recovered and 20% is discharged to the atmosphere. .

Therefore, the insulation gas recovery apparatus 20 as shown in FIG. 2 is disclosed to compensate for these disadvantages. The insulation gas recovery device 20 may recover a 99% or more of SF ₆ charged in the insulation device 1 by applying the vacuum pump 22 between the insulation device 1 and the compressor 24. .

However, while the insulation gas recovery apparatus 20 has excellent recovery rate of SF ₆ from the insulation device 1, air mixing due to diffusion during the recovery of the insulation gas and the use of the insulation device is inevitable. Therefore, the concentration reduction of the SF ₆ recovered in the insulation gas recovery device 20 inevitably occurs.

Therefore, impurities such as air mixed in the recovered SF ₆ should be removed. Due to this necessity, an insulating gas recovery device 30 having a purification section 34 has been developed as shown in FIG. 3 (see Japanese Patent Application Laid-Open No. 2000-246041, Korean Patent No. 10-0308404). In this case, the purification unit is mainly composed of applying a separator using oxygen / nitrogen and SF ₆ molecular size difference, or applying PSA (Pressure Swing Adsorption) using molecular size and adsorption characteristics.

The insulating gas recovery device 30 is a liquid state and cooled to a purification section 34 to the recovery unit 32 for recovering and presses the SF _6, to remove the impurities of the recovered SF _6, SF ₆ impurity was removed It includes a cold storage unit 36 for storing. The recovery unit 32 includes a vacuum pump and a compressor, and the purification unit 34 is a separate gas compressor or a vacuum pump for regenerating an adsorption layer to give a gas flow driving force to an adsorption tower or a separator for purifying gas. Is provided. In addition, the cold storage unit 36 is configured to include a cooler and a storage container.

However, this configuration has been developed from the point of view of recycling in the field by recovering the insulating gas from the device, purifying it. That is, even if a recovery rate of 99% or more is secured from the insulator, a large amount of SF ₆ air discharge is inevitable in the general refining process for removing air.

Therefore, efforts are needed to minimize the release of SF ₆ into the atmosphere. In addition, the achievement of this object should be carried out in a range in which the volume of the purification section is increased so as not to cause problems in use (particularly, mobility).

In the present invention, in order to solve the above problems, it is possible to minimize the SF ₆ gas discharged to the atmosphere in the refining process (0.1% or less), and at the same time the configuration of the insulation gas recovery device further reduced the volume compared to the existing refining process and its operation Give a way.

Representative device configuration using a separator in the purification unit in the insulating gas recovery device according to the prior art is shown in Republic of Korea Patent No. 10-0308404.

Figure 4 schematically shows the conceptual configuration of the Republic of Korea Patent No. 10-0308404, the biggest feature is to install the hollow fiber membrane 56 in the refining unit to remove the air, the separated gas back to the first adsorption layer ( 42. The feedback to the front end can be seen. However, in order to obtain high selectivity due to the characteristics of the hollow fiber membrane, there is a problem in that the selectivity is halved in order to increase the volume of the purification apparatus and to obtain high permeability.

In other words, in order to secure high recovery rate, secure high concentration SF ₆ , and minimize device volume, a new system configuration is needed to reduce SF ₆ emitted to the atmosphere during purification.

The development of the recovery / purification device for satisfying the above object is not completed. In other words, to date, most studies have not shown efforts to minimize SF ₆ lost during purification. However, the high concentration recovery and recycling aspects were of interest by proceeding with purification in the field.

Accordingly, a first object of the present invention is to provide an insulation gas recovery apparatus having a high recovery rate that achieves a loss amount of SF ₆ of 0.1% or less in the purification process.

A second object of the present invention is to provide a compact process by linking a hollow fiber membrane and a VPSA to achieve compactness of the apparatus.

A third object of the present invention is to provide a method for operating the apparatus.

The present invention for achieving the above object is a recovery unit for recovering and pressurizing SF ₆ connected to the insulator, a storage unit for liquefied and stored SF ₆ connected to the recovery unit, from the stored SF ₆ And a purifying part feeding back the concentrated SF ₆ to the recovery part by removing impurities, wherein the purifying part comprises a hollow fiber separator and a VPSA (Vacuum Pressure Swing Adsorption).

The hollow fiber membrane and the VPSA are arranged in series with respect to the storage unit.

In addition, the storage unit is characterized in that dwaeseo connected to the storage container and the storage container for storing the SF ₆ comprises a condenser for liquefying the SF _6, and retreats I moving parts Suga the tablet from the gas layer formed in the storage container do.

In addition, a constant pressure device is installed between the storage container and the refining unit to supply the refined gas at a predetermined pressure to the refining unit.

In addition, the insulating gas concentrated by the refining unit is circulated to an upstream side of the compressor included in the recovery unit.

In still another aspect of the present invention, there is provided a method for recovering insulation gas using the insulation gas recovery device, the method including vacuum removing air in the insulation gas recovery device before starting the recovery of the insulation gas, or stopping the insulation gas recovery device. Vacuum recovery of the insulating gas contained in the insulating gas recovery device before the.

Therefore, in the present invention, through the configuration as described above to minimize the amount of air discharged during the purification process to achieve more than 99% by weight SF ₆ recovery rate of the insulation gas recovery apparatus. At the same time, system volume increases can also be minimized.

The most important concept is to construct a hybrid system using the advantages of high permeability of hollow fiber membrane and high separation rate of adsorbent during purification. Accordingly, the separation membrane and the VPSA can provide a competitive insulation gas recovery device, compared to the purification system composed of independent processes.

More specifically, in the polyisulfone system having large pores in the hollow fiber membrane, the nitrogen permeation amount per unit area reaches 9 GPU (1 GPU = 10 ^-6 cm 3 (STP) / cm 2 × s × cm Hg) or more. Therefore, it occupies a small volume compared with the gas throughput. Thus, the high flux membrane as a first stage to lower to 80% by weight of SF ₆ or less, then, since it is a VPSA process flow rate is decreased by more than 70% state when applied in the adsorption step to obtain a high selectivity. As described above, the present invention has been completed through the sequence of the membrane process and the adsorption process and the combination of the respective characteristics.

In addition, in the present invention, impurities are mixed and added through the removal of air remaining in the device before the start of the insulation gas recovery device and the recovery of SF ₆ remaining in the device immediately before the end of the insulation gas recovery device. Processes are also proposed to minimize the release of SF ₆ .

The development of the recovery and purification device of the present invention provides a compact device capable of actively suppressing (attaining a 99% recovery rate) the release of insulating gas into the atmosphere. Therefore, by significantly reducing the warming contribution by SF ₆ discharged from the power industry, it provides an equipment capable of promoting the commercial development of the CDM (Clean Development Mechanism) in the industry.

Simple modifications and variations of the present invention are all within the scope of the present invention, and the specific scope of the present invention will be apparent from the appended claims.

1 is a configuration diagram of a first example of an insulation gas recovery apparatus according to the prior art.
2 is a configuration diagram of a second example of the insulation gas recovery apparatus according to the prior art.
3 is a configuration diagram of a third example of the insulation gas recovery apparatus according to the prior art.
4 is a configuration diagram of a fourth example of the insulation gas recovery apparatus according to the prior art.
5 is a conceptual block diagram of an insulation gas recovery apparatus according to an embodiment of the present invention.
FIG. 6 is a block diagram specifically illustrating a recovery unit, a purification unit, and a cooling storage unit in the insulation gas recovery device of FIG. 5.
FIG. 7 is a block diagram of an insulated gas recovery apparatus in detail illustrating an example of the VPSA in FIG. 6.
8 is a process flowchart of the insulation gas recovery method according to the present invention.
9 is a relation graph of pressure change in the insulation device according to the operating time of the recovery device.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. In adding reference numerals to components of the following drawings, it is determined that the same components have the same reference numerals as much as possible even if displayed on different drawings, and it is determined that they may unnecessarily obscure the subject matter of the present invention. Detailed descriptions of well-known functions and configurations will be omitted.

As described above, the present invention provides a compact device capable of recovering and purifying insulating gas from an insulating device.

In order to achieve the first object, the insulating gas recovery apparatus 100 according to the embodiment of the present invention, as shown in Figures 5 to 7, largely recovering unit 102, storage unit 104, It is configured to include a purification unit 106.

The recovery unit 102 is connected to the insulator 1 and serves to recover and pressurize SF ₆ , and includes a recovery vacuum pump 114 and a recovery compressor 118 for this purpose. The recovery unit 102 is configured to recover the insulating gas as soon as possible. In addition, a first adsorption part 112 for removing acid gas is installed in a recovery input tube 170 at the front end of the recovery vacuum pump 114, and a recovery output tube 180 at a rear end of the recovery compressor 118. The second adsorption part 120 for removing oil and water of the recovery compressor 118 is installed.

The first adsorption part 112 is disposed with a solid particle filling layer capable of adsorbing an acid gas. Therefore, while the insulating gas passes through the first adsorption part 112, acid gases (HF, H ₂ S, SF ₄ , SF ₂ , SOF ₂ , SO ₂ F _2, etc.) generated during the decomposition of SF ₆ are removed. do.

A front end of the first adsorption part 112 is provided with a shut-off valve 110 that can insulate the insulating gas recovery device 100 from the insulator 1 or the atmosphere. In addition, the recovery vacuum pump 114 is installed in the bypass pipe 174 connected to the recovery main pipe 172 at the front end of the recovery compressor 118. In addition, a switching valve 116 is provided on the output side of the recovery vacuum pump 114. The recovery vacuum pump 114 is connected to the first output pipe 176 connected to the recovery compressor 118 by the switching valve 116 or to the second output pipe 178 communicating with the atmosphere. It may be connected to the second output pipe (178).

Until the pressure of the insulating device 1 using the insulating gas and the storage container 122 is the same, the equilibrium is achieved without any driving force. In this case, the recovery compressor 118 is supplied to the recovery compressor 118 via the recovery main pipe 172 without passing through the recovery vacuum pump 114. Subsequently, the insulating gas is pressurized by the recovery compressor 118, supplied to the storage container 122, and liquefied and stored. In addition, the recovery rate is drastically reduced from the time when the pressure of the insulating device 1 is similar to the pressure of the storage container 122. Therefore, from this time, the vacuum pump 114 is decompressed to 10torr to recover more than 99% of the insulating gas.

The storage unit 104 includes a storage container 122 connected to the recovery output pipe 180, and a cooler 124 connected to the storage container 122 to liquefy SF ₆ to 30 ° C. or less.

The constant pressure device 108 is installed in the storage output pipe 182 of the storage unit 104. The positive pressure device 108 is configured to include a known positive pressure valve, and delivers the gas formed on the upper side of the storage container 122 to the purification unit 106 at a constant pressure.

In order to achieve the second object, the purification unit 106 is a hollow fiber separator 126 connected to the positive pressure output pipe 184 connected to the constant pressure device 108, and the hollow fiber separator 126 And a VPSA 128 connected to the first discharge pipe 186. The purification unit 106 minimizes the emission to the atmosphere during the purification process while satisfying the concentration for recycling the SF _{6 so} that the loss of the purification process is less than 0.1% by weight of the recovery amount. The hollow fiber separation membrane 126 is made of a polyisulfone-based hollow fiber membrane, the gas permeability is high while the N ₂ / SF ₆ selectivity is somewhat low (level 10-12).

In general, when the separation membrane or the PSA alone configuration, there is a disadvantage in that the quantity of the purification device and the peripheral device (compressor) is increased in order to maintain a high SF ₆ recovery rate. However, by using the characteristics of the hollow fiber membrane and the VPSA, the number of separators and peripherals (compressor, vacuum pump) can be minimized while minimizing the SF ₆ waste factor when the hollow fiber membrane 126 and the VPSA 128 are connected in series. It can be minimized.

In addition, the first purification pipe 190 of the hollow fiber membrane 126 and the second purification pipe 188 of the VPSA 128 are combined in a feedback pipe 192 to obtain SF ₆ purified by the recovery main pipe 172. Supply. In more detail, the feedback pipe 192 is disposed upstream than the point where the bypass pipe 174 branches from the recovery main pipe 172.

The VPSA 128 may be configured in various combinations, and in the embodiment of the present invention, as shown in FIG. 7, the tablet compressor 130 connected to the first discharge pipe 186 of the hollow fiber membrane 126. And a first adsorption tower 132 and a second adsorption tower 134 connected to the tablet compressor 130 and the first connection pipe 186, and to the first adsorption tower 132 and the second adsorption tower 134. It includes a purification vacuum pump 136 connected to the second connecting pipe (198). The second discharge pipe 194 is disposed in the first adsorption tower 132 and the second adsorption tower 134.

In more detail, air having a small molecular size in the insulating gas supplied to the hollow fiber membrane 126 is supplied to the tablet compressor 130 through the first discharge pipe 186, and in the tablet compressor 130. Pressurized in a range of 3-5atm is supplied to the first adsorption tower 132 and the second adsorption tower 134. Most of the SF ₆ in the first adsorption tower 132 and the second adsorption tower 134 is adsorbed by the filler (activated carbon-based) and moved to the second purification pipe 198, and the unadsorbed trace amount of SF ₆ and the air is the second It is discharged to the atmosphere through the discharge pipe (194). The first adsorption tower 132 and the second adsorption tower 134 adsorb the time corresponding to reaching 80 to 90% SF ₆ adsorption capacity, and the first adsorption tower 132 and the second adsorption tower 134 are mutually It is automatically adjusted by a connecting valve (not shown) to be replaced alternately.

Since the tablet compressor 130 is intended to supply a permeate gas having a constant pressure to the first adsorption tower 132 and the second adsorption tower 134, the hydrostatic pressure device 108 may be cleaned even if only a hydrostatic pressure gauge is used. Can achieve the purpose. However, in this configuration, the hydrostatic pressure gauge is required to be installed in the first purification pipe 190 (not shown).

The order has an important meaning. The insulating gas passes through the first adsorption part 112 to remove acid gas, and is compressed to 20 atm or more by the recovery compressor 118. Subsequently, it passes through the second adsorption part 120 for removing the compressor oil and water. Subsequently, passing through a heat exchanger (not shown) connected to the cooler 124, the temperature is cooled to 30 ° C. or less and moved to the storage container 122.

Insulating gas is cooled while passing through a heat exchanger to below 30 ℃ most is converted to liquid and gas pollution, some of SF ₆ is moved to the gas form. The concentration of SF _{6 in} the gas phase changes with temperature and pressure.

Accordingly, SF ₆ in the liquid phase is present in the lower portion of the storage container 122, and a gaseous non-condensable gas and a part of the SF ₆ gas are present in the upper portion. That is, most of the SF ₆ already contained in the insulating gas is converted to the liquid phase through the compression cooling process, and the separation process naturally reaches a high completion state so that some SF ₆ gas is present in the non-condensable gas. If further described, the cooling by the pressing and the cooler 124 by the number of times the compressor (118), SF _6, most are converted to liquid, a low-molecular substance produced by the incoming air and SF ₆ decomposition process (CF _4, C ₂ F ₄ , C ₂ F _6, etc.) will stay on top of the vessel in the gas phase.

Therefore, when constructing the purification process for the gas phase above the storage container, the total amount of gas to be transported is also reduced by more than 95%. Therefore, the total amount of gas to be treated in the refining process is supplied to the refining unit 106 with a gas volume of up to 10% less than the process of refining and storing the existing recovered gas (see Japanese Patent Application Laid-Open No. 2000-135412).

In addition, the separation efficiency is improved by increasing the concentration of pollutants acting as a factor of separation efficiency in the separation process. In addition, the SF ₆ recovery rate in the VPSA is very high by reducing the flow rate of the process gas.

Insulating gas recovery apparatus 100 according to an embodiment of the present invention is basically configured as described above. Hereinafter, an insulation gas recovery method using the insulation gas recovery device 100 will be described.

First, in the start preparation step (S10), the air mixed in advance in the insulating gas recovery device 100 is removed. In particular, it is important to remove the air mixed in the purification unit 106 to maintain the purification capacity of the purification unit 106. To this end, in a state in which the shutoff valve 110 is closed, the purification vacuum pump 136 and the recovery vacuum pump 114 are operated, and the three-way valve 116 is connected to the second output pipe 178. Be sure to The start preparation step (S10) is made for a predetermined start preparation time, the target pressure is 10torr in the purification unit 106. Therefore, the start preparation time may vary depending on the size of the insulation gas recovery apparatus 100.

Next, in the insulating gas recovery step S20, the shutoff valve 110 is opened, and the three-way valve 116 is connected to the first output pipe 178. Of course, the recovery input tube 170 is in a state connected with the insulating device (1). The insulation gas recovery step (S20) aims at a pressure of 10torr in the insulation device 1, and thus the recovery time may vary depending on the scale of the insulation device 1.

When the size of the insulation device 1 is 1.7 million KV, the SF ₆ concentration (97%) of the recyclable level can be reached in the insulation device by driving the purification time 2 hours, and SF ₆ discharged to the atmosphere during the purification process Less than 0.1% can be achieved. If excessive purification time is given, the concentration of the insulating gas can be concentrated up to 99% or more, but the amount of SF ₆ contained in the atmospheric exhaust gas is also increased. Therefore, a purification time is given based on a state in which an SF ₆ concentration of 97% or more capable of exhibiting insulation efficiency can be reached (maximum 2 hours). This determination can be judged using an SF ₆ analyzer.

In particular, the recovery rate begins to decrease rapidly, and from the time point at which recovery is started to the recovery vacuum pump 114, operation of the purification unit is started. That is, since the inflow amount of the insulating gas is reduced, the recovery compressor 118 is operated at a compression capacity or less, and the recovery unit 102 may supply the insulating gas circulated through the feedback pipe 192 in the purification unit 106. Does not affect the recovery rate of the insulation gas.

Then, the maintenance device 1 is inspected and repaired (S30).

When the maintenance is completed, the air in the insulator 1 is removed (S40). The pressure in the insulator 1 is aimed at 10 torr or less, so the removal time may vary depending on the size of the insulator 1.

Thereafter, SF ₆ in the storage container 60 is charged in the insulator 1 (S50).

Finally, a final preparation step for recovering the insulating gas remaining in the insulating gas recovery device 100, in particular in the purification section 106 is carried out (S60). To this end, in a state in which the shutoff valve 110 is closed, the purification vacuum pump 136 and the recovery vacuum pump 114 are operated, and the three-way valve 116 is connected to the first output pipe 176. Be sure to The end preparation step (S60) is made for a predetermined end preparation time, the target pressure is 10torr or less in the purification unit 106. Therefore, the termination preparation time may vary depending on the size of the insulation gas recovery device 100.

As such, the SF ₆ atmosphere included in the purification apparatus is removed by removing air from the insulation gas through pre-run and post-run before the end of the purification unit 106. It is possible to prevent the release of air by actively suppressing heavy emissions. This stage of operation can be carried out in the operation logic or manually carried out by the equipment operator.

As described above, it has been described with reference to the preferred embodiment of the present invention, but those skilled in the art various modifications and changes of the present invention without departing from the spirit and scope of the present invention described in the claims below I can understand that you can.

1: insulation equipment 10,20,30,40,100: insulation gas recovery system
12,24,48 Compressor 14,26,54 Cooler
16,28,52: storage container 22,46: vacuum pump
32: recovery section 34: purification section
36: cooling storage section 42: the first adsorption layer
44: meter 50: second adsorption layer
56: hollow fiber membrane 102: recovery unit
104: refining unit 106: refining unit
108: constant pressure device 110: shut-off valve
112: first adsorption portion 114: recovery vacuum pump
116: three-way valve 118: recovery compressor
120: second adsorption portion 122: storage container
124: cooler 126: hollow fiber membrane
128: VPSA 130: tablet compressor
132: first adsorption tower 134: second adsorption tower
136: refined vacuum pump 170: recovery input tube
172: recovery main building 174: bypass pipe
176: first output tube 178: second output tube
180: recovery output tube 182: storage output tube
184: constant pressure output pipe 186: first discharge pipe
188: Second Refining Officer 190: First Refining Officer
192: feedback pipe 194: second discharge pipe
196: first connector 198: second connector

Claims (7)

Is connected to the insulated apparatus recovering SF ₆ and a pressure recovery section and the stripping section dwaeseo connected to the SF ₆ concentration to remove impurities of the recovered SF ₆ from the liquid storing a storage unit with the stored SF ₆ in which the number of times that It includes a purification unit for feeding back negatively,
The refining unit is an insulation gas recovery device comprising a hollow fiber membrane and VPSA (Vacuum Pressure Swing Adsorption).
The insulation gas recovery apparatus of claim 1, wherein the hollow fiber separator and the VPSA are disposed in series with respect to the storage unit.
The method of claim 1, wherein the storage unit moving from the gas layer is connected to the storage vessel for storing the SF _6, the reservoir comprises a cooler for liquefying the SF _6, and formed in the storage container retreat I part Suga the tablet Insulation gas recovery apparatus, characterized in that.
4. The insulation gas recovery apparatus according to claim 3, wherein a constant pressure device is provided between the storage container and the refining unit to supply a refined gas at a predetermined pressure to the refining unit.
2. The insulation gas recovery apparatus according to claim 1, wherein the insulation gas concentrated by the purification section is circulated upstream of the compressor included in the recovery section.
An insulation gas recovery method using the insulation gas recovery apparatus according to any one of claims 1 to 5, characterized in that it comprises vacuuming the air in the insulation gas recovery apparatus before starting the recovery of the insulation gas. Insulation gas recovery method.
An insulation gas recovery method using the insulation gas recovery apparatus according to any one of claims 1 to 5, comprising the step of recovering the insulation gas contained in the insulation gas recovery apparatus before stopping the insulation gas recovery apparatus. Insulation gas recovery method, characterized in that.

Images