JPS6326497A - Gas replacement recovery device - Google Patents

Abstract

PURPOSE:To reduce gas losses by compressing and cooling a discharged gas and air mixture so that only gases are liquefied, and after the liquefied gases have been refined by separating air, vaporizing them so as to be circulated into a vessel. CONSTITUTION:Liquefied SF6 gas is vaporized and reduced in pressure in a vaporizer 28, and is introduced into a vessel 2, and at the same time the mixed gas of air and SF6 gas is discharged from an upper port 3. Then, it is introduced into a gas compressor 19 to be compressed, and is liquefied in a cooling separator 24, sent to a vaporizer 28, and via a four-way changeover valve 8, is circulated into the vessel 2 being a SF6 gas insulating apparatus. Thus, gas losses at the time of gas replacement can be reduced.

Description

[Detailed description of the invention] (a) Industrial application field The present invention efficiently replaces air in a non-pressure resistant container with gas,
The present invention relates to a gas replacement and recovery device that reduces gas loss during gas replacement, and recovers and reuses gas in a container with less loss.

(b) Conventional technology In general, methods for completely replacing the gas in a container with gas from a pond include, in the case of a pressure-resistant container, a method in which the inside of the container is evacuated to a vacuum, and then the target gas is introduced; A method is used in which the gas is filled with gas, then discharged to normal pressure, and this process is repeated until a predetermined gas purity is reached. When replacing gas in a non-pressure-resistant container, the above method cannot be used, so the target gas is poured into the container to be replaced, and the gas is replaced gradually until the purity of the gas in the container reaches the specified level. A method is used in which gas is circulated until it reaches purity. In addition, when recovering gas filled in a container, the gas in the container is sucked up to atmospheric pressure or lower using a compressor and a vacuum pump.

(C) Problems to be Solved by the Invention In order to perform gas replacement in a non-pressure resistant container using the conventional gas flow method,
Depending on the structure of the gas flow path inside the container and the target purity of the replacement gas, it is necessary to circulate gas several times to several tens of times the volume of the container. When filling electrical equipment with sulfur hexafluoride (hereinafter referred to as SF6), which is an insulating gas, if gas replacement is performed using a conventional flow method, a large amount of expensive SF6 gas is required. Further, with conventional recovery means, it is impossible to recover SF6 gas filled in a non-pressure resistant container.

Therefore, an object of the present invention is to provide a gas replacement and recovery device that causes less loss of gas when replacing gas in a non-pressure resistant container by a flow method, and can pollute gas replacement to a desired purity level. .

(d) Means for Solving the Problems In order to achieve the above object, the inventor of the present invention has conducted extensive research, and as a result, the present inventor has developed a method of circulating displacement gas in the container and compressing the mixture of exhausted air and gas supply. After cooling and liquefying only the gas, separating it from air and purifying it, the liquefied gas is vaporized and circulated within the container, thereby reducing the loss of replacement gas and replacing the gas within the container to a predetermined concentration. They discovered that it is possible to allow air to flow into a container containing gas, then suck the mixture of gas and air, liquefy and separate only the gas content, and recover it, thus completing the present invention. reached.

Next, the contents of the present invention will be explained in detail with reference to the drawings, taking as an example an apparatus for replacing gas with SF6 gas. FIG. 1 is a system diagram of an example of the gas replacement recovery apparatus of the present invention for 8F6 replacement.

(1) is a gas replacement and recovery device, and has a connection port A (5) and a connection port connected to the upper port (3) and lower port (4), respectively, of the container (2) to be replaced with gas such as SF6 gas insulated equipment. Equipped with reading opening B (6).

Piping (9) connecting from connection port A (5) to four-way switching valve (8) via valve (7) and piping (9) connecting from connection port B (6) to four-way switching valve (8) via valve α0. A wiring WOυ is provided that connects to the opposing position. Other 1 of the four-way switching valve (8)
A recovery pipe A3 leading to the dryer (6) from one opening is provided, and a bypass pipe Q branching from the recovery pipe W (13) is provided with a concentration/moisture meter 09 for measuring gas concentration and moisture.

Further, an air introduction pipe Wαη is provided which branches from the middle of the piping from the connection port A (5) to the valve (7) and opens to the atmosphere via the air inflow valve αQ.

A gas pipe (4) is provided that leads from the V-liar αa to the gas compressor via valve 0 (to), and the gas pipe I21) coming out of the gas compressor is connected to an oil separator (a) and an air cooler (a). It then connects to the cooling separator @. The dryer q2 consists of a filled tube filled with a solid desiccant such as activated zeolite.

As the gas compressor O0, any known compressor such as a reciprocating compressor or a rotary compressor can be used. The oil separator (a) is equipped with an oil mist filter for removing oil mist mixed in by the gas compressor a1. However, if the gas compressor is an oil-less type, the oil separator can be omitted.

The air cooler@ is equipped with a fin tube and a fan, and primarily cools the gas that has been compressed by the gas compressor αl and has reached a high temperature. A refrigerant at a lower temperature than the refrigerator @ is circulated through the cooling separator (c) to cool the gas to the liquefaction temperature and separate the gas and liquid.

The separated liquefied gas is stored in the lower part of the cooling separator (c).

A liquefied gas pipe (to) and a non-condensable gas exhaust pipe (a) come out from the cooling separator (c), and the liquefied gas pipe (to) connects to the vaporizer @, and from the vaporizer (bottom) via the valve handle, the four directions are connected. Switching valve (
8) Provide a gas delivery pipe connected to the other port.

On the other hand, the gas piping from the dryer (2) to the valve (to) branches from the middle, passes through the valve (7), the blower 6) and the valve 0, and then goes from the valve (a) to the four-way switching valve (8). A gas circulation pipe (toward) is provided that joins the first gas delivery pipe. Furthermore, S
The gas common supply pipe (7) from the gas supply port diagram that connects to the F6 gas cylinder (not shown) is connected from the cooling separator → to the vaporizer (
It joins the liquefied gas pipe (g) that leads to (g).

(e) Operation Next, the operation of the gas replacement and recovery apparatus shown in FIG. 1 will be explained. First, put S into the container (2) for S F6 gas insulated equipment, etc.
When replacing F6 gas, set the four-way switching valve (8) to the first
Switch to the direction shown by the solid line in the figure, introduce liquefied SF6 gas from the SF6 gas cylinder via gas supply port ), SF6 gas is introduced into the container (2) through the lower port (4). At the same time, a mixed gas of air and SF6 gas is discharged from the upper port (3) of the container (2), and the four-way switching valve (8) is connected to the connection port A (5) of the gas replacement and recovery device (1) connected to this. After that, it is introduced into a dryer (a), where a small amount of moisture is removed and completely dried, and then introduced into a gas compressor α) where it is compressed to 30 kg f/cyl 0 or more. The compressed mixed gas is removed with oil mist in an oil separator (a), cooled down to around room temperature in an air cooler), and then cooled down to around room temperature in a cooling separator (c), where the oil mist is removed depending on the gas pressure.
It is cooled to below °C, and most of the SF6 gas is liquefied. A non-condensable gas such as air containing a trace amount of SF6 gas corresponding to the vapor pressure of the liquefied SF6@cooling temperature is separated into gas and liquid by the cooling separator (c), and the gas is discharged from the exhaust pipe gradient. The liquefied SF6 is sent to the vaporizer (G) at the same time or in place of the SF6 from the cylinder, is depressurized to almost normal pressure, heated and vaporized, and then passes through the four-way switching valve (8) to become SF6.
It is circulated to the container (1) of the gas insulated equipment.

Before the recovered gas enters the dryer (A), a part of it is passed through the concentration moisture meter 09 to measure the concentration of the recovered gas, and the concentration of the recovered gas is measured.
When the concentration of 6 gases is reached, the operation of the device is stopped and it is disconnected from the container.

After the SF6 in the container (1) reaches a predetermined concentration, if it is necessary to further dry the inside of the container, use the valves α and Q.
), open the valve (7) and valve 0, operate the blower 61), circulate the gas into the container (1) via the dryer @ and the gas circulation distribution W (c), and set the concentration moisture meter 00. The circulation of SF6 gas is continued until the moisture content measured in step reaches a predetermined value.

Furthermore, the gas replacement and recovery device of the present invention can also recover gas such as SF6 filled in a container by replacing it with air or the like. For example, the SF6 in the container (1) is
When recovering gas, switch the four-way switching valve (8) to the recovery position shown by the dotted line in Figure 1, close the valve (7), close the air inflow valve Qfl, and open the air from the connection port A (5). Container (1)
After allowing air to flow into the container, the gas compressor 4 is operated to suck the gas inside the container.

The sucked mixed gas of SF6 and air is cooled under pressure, and liquefied SF5 is separated in a cooling separator. The separated and recovered SF6 can also be taken out via the liquefied gas recovery valve (2).

During operation of the above gas replacement and recovery device, the gas pressure at connection port A (5) or connection port B (6) is measured, and the pressure is always approximately +0.2 to -0, approximately 2 kg f /cyAG. The operation of the gas compressor a9 and the vaporizer or blower 6η is automatically adjusted so that the pressure becomes normal.

In the above explanation, the case where the gas is replaced with SF6 gas and recovered is explained as an example. However, the gas replacement and recovery device of the present invention is not limited to the case where the gas is replaced with SF6 gas. Used for the replacement and recovery of all possible gases.

(f) Example An SF6 gas insulated device having a volume of 5H was replaced with SF6 gas using the gas replacement device of the present invention. When the gas compressor takes in gas at a rate of 16.2 m/hr and pressurizes to 33 kg f/c4 G, and the cooling temperature of the cooling separator is -25°C, the SF6 gas concentration can be reduced within 1 hour and 30 minutes of operation. It reached 90%.

At this time, the amount of SF6 gas supplied from the cylinder during replacement was 60 kg, the amount of SF6 gas in the equipment after replacement was 34 kg, the amount of gas separated and recovered by the cooling separator was 11 kg, and the gas exhausted and consumed together with air was 111 kg. Therefore, the gas replacement efficiency was.

Next, S with an internal volume of 5 i filled with this 90% SF6 gas
SF6 gas was collected from F6 gas insulated equipment using the device of the present invention under the same operating conditions as above for 1 hour.
23 kg of liquefied SF6 gas was recovered in less than 0 minutes of operation time. Therefore, the recovery efficiency was.

(g) Effects of the Invention According to the gas replacement device of the present invention, gas can be replaced to an arbitrary concentration by a flow method while maintaining the pressure inside the non-pressure resistant container at approximately normal pressure, and at that time, Since the gas discharged together with air etc. can be liquefied and separated, recovered and circulated, there is little loss of gas during gas replacement and high replacement efficiency can be achieved.

Further, the gas filled in the non-pressure resistant container can be efficiently recovered as liquid and gas while maintaining the inside of the container at normal pressure.

Furthermore, if the gas is circulated through a dryer, the inside of the container can be completely dried.

[Brief explanation of the drawing]

FIG. 1 is a system diagram of an example of the gas replacement apparatus of the present invention. (1)...Gas replacement device, (2)...Container, (
3)...Top opening, (4)...Bottom opening, (
5)... Connection port A (6)... Connection port B, (7), α
0, α (to), punishment, (to), (i)... valve, (8).
... Four-way switching valve, (9), 01) ... Piping, (
To)...Dryer, α1...Recovery piping, α
→...Bypass piping, αQ...Concentration moisture meter, (
lilG...Air inflow valve, (17)...Air introduction pipe, al...Gas compressor, Kan, Ql)・
...Gas piping, (a)...Oil separator, @...
・Air cooler, (c)...Cooling separator, (to)
... Refrigerator, @... Liquefied gas piping, Incline... Exhaust pipe, (4)... Vaporizer, (A)... Gas delivery piping, (B)... Blower, (T)... )・
...Gas circulation piping, (b)...Gas supply port, (
7)... Gas supply piping, (7)... Liquefied gas recovery valve.

Claims (3)

[Claims] (1) Vaporization means that reduces the pressure of high-pressure liquefied replacement gas to almost normal pressure, vaporizes it, and introduces it into the container to be replaced, and a mixed gas that is pushed out by the introduced replacement gas and discharged from the container to be replaced. a compression means for compressing; a cooling means for cooling and liquefying the compressed mixed gas from the compression means to a temperature below the liquefaction temperature of the replacement gas in the mixed gas under the pressure thereof;
a separation and recovery means for separating the liquefied substitution gas and non-condensable gas from the mixed gas into gas and liquid and recovering the liquefied substitution gas, and circulating the recovered liquefied substitution gas to the vaporization means. A gas replacement recovery device characterized by: (2) The gas replacement and recovery device according to claim 1, further comprising drying means for drying the mixed gas discharged from the container to be replaced before introducing it into the compression means. (3) The gas replacement and recovery device according to claim 2, further comprising circulation means for directly blowing the mixed gas dried by the drying means and introducing it into the container to be replaced.