KR102439151B1 - High-purity sulfur hexafluoride purification apparatus and purification method using same - Google Patents

Abstract

The present invention relates to a high purity sulfur hexafluoride purification apparatus and a purification method using the same. The high purity sulfur hexafluoride purification apparatus comprises: a supply unit supplying a target gas containing sulfur hexafluoride; a preprocessing unit including a first scrubber allowing the target gas to pass through a chamber, in which a sodium hydroxide solution is sprayed, so that the sodium hydroxide solution and a soluble gas component included in the target gas are contacted and collected, and a second scrubber allowing the target gas which passes through the first scrubber to pass through the chamber in which water is sprayed so that the soluble gas component included in the target gas is contacted to the water and collected; a moisture removal unit passing the target gas, which passes through the preprocessing unit, through a condenser or a chemical dryer filled with an adsorbent to remove mixed moisture so that a moisture concentration is maintained at 0.1-1 ppm; and a distillation unit for heating at high pressure and high temperature to separate sulfur hexafluoride by using the difference in boiling point so as to remove a non-reactive gas composed of oxygen, nitrogen, and carbon tetrafluoride mixed in the target gas from which moisture is removed in the moisture removal unit, or any one or two or more highly toxic substances selected from a group consisting of SO_2F_2, S_2F_10, and S_2F_10O. Accordingly, even if a concentration of recovered sulfur hexafluoride is low (10%), sulfur hexafluoride can be recovered and recycled into high purity sulfur hexafluoride through step-by-step impurity removal.

Description

High-purity sulfur hexafluoride purification apparatus and purification method using same

The present invention relates to a high-purity sulfur hexafluoride purification apparatus by distillation method and a purification method using the same.

Generally, high-voltage electric circuit breakers or switchgear used in substations use sulfur hexafluoride gas, an insulating gas. The global warming potential of sulfur hexafluoride gas is 23,900 times that of carbon dioxide and the atmospheric residual period is 3200 years. have a major impact on global warming.

Currently, recovery and reuse related to "Technical Guidelines for SF6 Gas Analysis and Treatment in Electrical Equipment [KOSHA GUIDE E-123-2012]" and "SF6 and SF6 Mixed Gas Recovery and Reuse Technology [SPS KOEMA 0941:2015]" Although well documented, there is no section on techniques for efficient and high-quality sulfur hexafluoride regeneration.

Low-quality sulfur hexafluoride regenerated with sulfur hexafluoride recovery and reuse technology causes frequent breakdowns and short lifespan of high-voltage electric circuit breakers and switchgear.

The newly developed purification technology for sulfur hexafluoride includes a method using a membrane, a solidification method using a deep cooling method, and a distillation method using a difference in boiling point.

In general, the quality of sulfur hexafluoride recovered from high-voltage electric circuit breakers or switchgear is 30% to 97% of sulfur hexafluoride content due to atmospheric mixing in the recovery process or problems with electric circuit breakers or switchgear itself, and the content of toxic substances is sometimes 10,000 ppm. Excessive cases occur.

If the sulfur hexafluoride content in the recovered container is less than 10%, it is preferable to treat it by incineration or other methods.

The quality of sulfur hexafluoride recovered from most high-voltage electric circuit breakers or switchgear in the regeneration process consists of 95% or more, and contains more than 5000 ppm of toxic gas.

Therefore, a process for removing harmful toxic gases is essential.

Republic of Korea Patent No. 10-1095199

The present invention has been devised to solve the problems of the prior art, and a high-purity sulfur hexafluoride purification device capable of stably regenerating sulfur hexafluoride having the same quality as a new product by regenerating high-quality sulfur hexafluoride with a high recovery rate; An object of the present invention is to provide a purification method using the same.

The above object of the present invention, the supply unit for supplying the target gas containing sulfur hexafluoride; A first scrubber for allowing the target gas to pass through a chamber into which the sodium hydroxide solution is sprayed so that the sodium hydroxide solution and the soluble gas component contained in the target gas are in contact and collected, and the target gas passing through the first scrubber is water a pre-processing unit having a second scrubber that allows the soluble gas component contained in the target gas to contact and collect water while passing through the sprayed chamber; a water removal unit for passing the target gas that has passed through the pretreatment unit through a condenser or a chemical dryer filled with an adsorbent to remove the mixed water and maintain the water concentration at 0.1 to 1 ppm; And any one selected from the group consisting of a non-reactive gas or SO ₂ F ₂ , S ₂ F ₁₀ and S ₂ F ₁₀ O consisting of oxygen, nitrogen and tetrafluorocarbon mixed into the target gas from which moisture has been removed by the water removal unit or a distillation unit heating at high pressure and high temperature to separate from sulfur hexafluoride by using the boiling point difference to remove 2 or more highly toxic substances.

The adsorbent of the water removal unit is characterized in that it is selected from the group consisting of molecular sieves, alumina and silica gel.

The distillation unit includes a primary distillation column and a secondary distillation column for removing the toxic substances mixed in the target gas obtained from the primary distillation column, wherein the primary distillation column includes an inlet through which the target gas is introduced; It is characterized in that it comprises a main body having a lead-out portion formed in the upper portion, a heating portion formed in an inner lower portion of the main body, and a heat exchanger formed in an upper end portion of the main body, wherein the heating portion is an electric heater or a steam line.

The secondary distillation column is characterized in that it is operated 1 to 5 bar higher than the primary distillation column.

The first-stage heat exchanger of the primary distillation column is operated at 20-30 bar, -20 to -45 °C, and the second stage heat exchanger is operated at 40-70 bar, -30 to -50 °C, and 1 of the secondary distillation column The stage heat exchanger is characterized in that it is operated at 20 to 30 bar, -20 to -45 °C.

Further comprising; a separation unit for separating sulfur hexafluoride mixed in the target gas obtained in the first-stage heat exchanger of the primary distillation column, wherein the separation unit includes a freezer for solidifying only sulfur hexafluoride by freezing, and in the freezer It is characterized in that only sulfur hexafluoride is frozen by freezing at -180°C to -67°C, and oxygen, nitrogen, and carbon tetrafluoride, which are non-reactive at low temperatures, are separated.

The above-described object of the present invention, one step of supplying a target gas containing sulfur hexafluoride; Step 2-1 of collecting soluble gas components while passing the target gas through a first scrubber sprayed with sodium hydroxide solution; a 2-2 step of collecting the soluble gas component by passing the target gas that has passed through the 2-1 step through a second scrubber sprayed with water; a third step of removing moisture by allowing the target gas that has passed through step 2-2 to be dried while passing through a condenser or a dryer filled with an adsorbent; After the target gas from which moisture has been removed in step 3 is supplied to the primary distillation column and heated, it is passed through a heat exchanger to separate oxygen, nitrogen and carbon tetrafluorocarbon, which has a lower freezing point than sulfur hexafluoride, and is transferred to the separator to separate the freezer. 4-1 process in which oxygen, nitrogen, and carbon tetrafluoride are removed using the difference in freezing point and sulfur hexafluoride is recovered to the primary distillation column; a 4-2 step of reheating the target gas of the primary distillation column in the secondary distillation column after the 4-1 step to evaporate and remove the toxic substances; and step 5 of filling the container with the dried target gas by passing it through the moisture drying unit after step 4-2.

The adsorbent in step 3 is characterized in that it is selected from the group consisting of molecular sieve, alumina and silica gel.

The 4-1 process is characterized in that it is heated by electricity or steam in the range of 20 to 30 bar, 50 to 100 ℃.

The 4-2 process is characterized in that the total content of the highly toxic substance is 0.5 to 1 parts by weight based on 100 parts by weight of the target gas containing sulfur hexafluoride.

The soluble gas component of step 2-1 or step 2-2 is HF, SO ₂ F ₂ , SO ₂ , H ₂ SO ₃ , SOF ₂ , SF ₄ , SF ₂ , S ₂ F ₂ and S ₂ F ₁₀ O It is characterized in that any one or two or more selected from the group consisting of.

According to the present invention, it is possible to recover sulfur hexafluoride even when the concentration (10%) of the recovered sulfur hexafluoride is low, and it is possible to reproduce with high purity sulfur hexafluoride quality by stepwise removal of impurities, and it is possible to secure stable quality through continuous operation .

1 is a block diagram of a high-purity sulfur hexafluoride purification apparatus according to the present invention;
2 is a side view schematically showing the 'supporting device' of the 'first and second scrubbers' in the high-purity sulfur hexafluoride purification apparatus according to the present invention;
Figure 3 is a front view schematically showing the 'support device' of the 'first and second scrubbers' in the high-purity sulfur hexafluoride purification apparatus according to the present invention.
4 is a process flow diagram for a high-purity sulfur hexafluoride purification method according to the present invention;
5 is a gas chromatography of the target gas purified according to the present invention.

Hereinafter, preferred embodiments will be described in detail with reference to the accompanying drawings.

The embodiments to be described below are intended to explain in detail enough to be easily implemented by those of ordinary skill in the art to which the present invention pertains, thereby limiting the technical spirit and scope of the present invention. doesn't mean

In addition, the size or shape of the components shown in the drawings may be exaggerated for clarity and convenience of explanation, and the terms specifically defined in consideration of the configuration and operation of the present invention may vary depending on the intention or custom of the user or operator. It should be noted that definitions of these terms should be made based on the content throughout this specification.

Of the accompanying drawings, FIG. 2 is a side view schematically showing the 'support device' of the 'first and second scrubbers' in the high-purity sulfur hexafluoride purification apparatus according to the present invention, and FIG. 3 is a high-purity sulfur hexafluoride purification apparatus according to the present invention. A schematic front view of the 'supporting device' of the '1st and 2nd scrubbers' in Fig. 4 is a process flow diagram for a method for purifying high-purity sulfur hexafluoride according to the present invention, and FIG. 5 is a gas chromatography of a target gas purified according to the present invention.

As shown in Figure 1, the high-purity sulfur hexafluoride purification apparatus according to the present invention,

a supply unit 100 for supplying a target gas containing sulfur hexafluoride;

A first scrubber 210 for allowing the target gas to pass through the chamber to which the sodium hydroxide solution is sprayed so that the sodium hydroxide solution and the soluble gas component contained in the target gas are in contact and collected;

A pre-processing unit 200 having a second scrubber 220 that allows the target gas that has passed through the first scrubber 210 to contact and collect the soluble gas component contained in the target gas in water while passing through a chamber in which water is sprayed. ;

Water removal unit 300 for passing the target gas that has passed through the pre-processing unit 200 through a condenser or a chemical dryer 380 filled with an adsorbent to remove the mixed moisture so that the moisture concentration is maintained at 0.1 to 1 ppm; and

Selected from the group consisting of oxygen, nitrogen, and non-reactive gas or SO ₂ F ₂ , S ₂ F ₁₀ and S ₂ F ₁₀ O made up of oxygen, nitrogen and tetrafluorocarbon mixed in the target gas from which moisture has been removed by the water removal unit 300 . Distillation unit 400 for heating at high pressure and high temperature so as to be separated from sulfur hexafluoride by using the boiling point difference to remove any one or two or more highly toxic substances;

includes

The supply unit 100 includes a sulfur hexafluoride recovery container 120 filled with the target gas containing sulfur hexafluoride to supply the target gas containing the contaminated sulfur hexafluoride generated in the power facility.

Sulfur hexafluoride contamination is caused by improper handling of gases, leaks, desorption from surfaces, bulk materials and adsorbers, discharge decomposition, secondary reactions of discharge decomposition products, and mechanical generation of dust particles.

Contamination by leakage is caused by air and moisture that diffuse and penetrate into the inside of the compression container because the partial pressure of the air and water vapor outside the container is higher than that inside the container.

Contamination by desorption is caused by moisture and gas, which are adsorbed on the inner surface of the equipment or adsorbed on the bulk material before the equipment is assembled. Moisture builds up on the metal surface and a cleaning agent may remain. Polymers contain moisture inside the bulk, which is the most important moisture source inside the system.

Decomposition by discharge is caused by corona-type partial discharge, spark discharge, switching arc, or electrical discharge by failure arc.

Metal dust particles are generated by rubbing of the primary circuit contacts, and when these particles fall on a high electric field such as an insulating barrier, tracking occurs on the surface of the insulator. leads to flashover

The adsorbent of the moisture removal unit 300 may be selected from the group consisting of molecular sieves, alumina and silica gel.

Molecular sieve (molecular sieve) has a large amount of thin pores with uniform diameter, so it has a clear adsorption force, and thus has an action of sieving molecules. It is used as an industrial desiccant, absorbent such as carbon dioxide or hydrogen sulfide, and sieving molecules such as normal paraffin and isoparaffin. In addition, it has various catalytic activities such as decomposition, polymerization, isomerization, and heterogeneity of hydrocarbons, and is also excellent as a catalyst carrier.

On the other hand, in order to remove oxygen, nitrogen, and carbon tetrafluoride mixed in the target gas from which moisture has been removed in the water removal unit 300, a distillation unit heating at high pressure and high temperature to separate from sulfur hexafluoride by using the boiling point difference ( 400); may include.

In the recovered sulfur hexafluoride gas from which the soluble gas and moisture have been removed, there are a significant amount of gases with little reactivity that cannot be removed, such as oxygen (O ₂ ), nitrogen (N ₂ ), and carbon tetrafluorocarbon (CF ₄ ).

These less reactive gases are composed of high boiling points, and each boiling point is O ₂ -183.0°C, N ₂ -195.8°C, CF ₄ -127.8°C, etc., which is very low compared to the boiling point of SF ₆ -50.8°C.

Separation of these substances is possible using a low-temperature high-pressure distillation column using the difference in boiling point.

The distillation unit 400 is composed of first and second stage heat exchangers 416-1 and 416-2, and the first stage heat exchanger 416-1 operates for the purpose of removing O ₂ , N ₂ , CF ₄ having a low boiling point. and the second stage heat exchanger 416-2 is operated for the purpose of removing very toxic substances present in trace amounts.

The distillation unit 400 is a non-reactive gas or SO ₂ F ₂ , S ₂ F ₁₀ and S ₂ F ₁₀ O composed of oxygen, nitrogen and tetrafluorocarbon mixed in the target gas from which moisture has been removed by the water removal unit 300 . Removes any one or two or more highly toxic substances selected from the group consisting of.

The distillation unit 400 is composed of a primary distillation column 410 and a secondary distillation column 420 heated to 20-30 bar, 50-100 ° C.

The primary distillation column 410 removes a non-reactive gas consisting of oxygen, nitrogen, and carbon tetrafluorocarbon.

The secondary distillation column 420 removes any one or two or more highly toxic substances selected from the group consisting of SO ₂ F ₂ , S ₂ F ₁₀ and S ₂ F ₁₀ O.

The first-stage heat exchanger (416-1) of the primary distillation column 140 is operated at 20-30 bar, -20 to -45 °C, and the second-stage heat exchanger (416-2) is 40 to 70 bar, -30 It is operated at ~-50 ℃, the first stage heat exchanger 426 of the secondary distillation tower 420 is operated at 20 ~ 30 bar, -20 ~ -45 ℃.

The primary distillation column 410 includes a main body 413 having an inlet 411 through which a target gas is introduced, an outlet 412 formed thereon, and a heating unit 415 formed in the lower inner side of the main body 413 . ) and a first and second stage heat exchanger 416 connected to the upper end of the main body 413 .

Preferably, the heating unit 415 includes a water tank in which water is stored, and an electric heater or a steam line that heats the water tank to evaporate water to generate water vapor.

The primary distillation column 410 is operated at a pressure of 20-30 bar through a compressor, and the bottom temperature is heated with electricity or steam in the range of 50-100 ℃.

The gas that is connected to the upper end of the primary distillation column 410 and passed through the first-stage heat exchanger 416-1 and the second-stage heat exchanger 416-2 is cooled in the freezer of the separation unit, and the separated sulfur hexafluoride is first It is recovered back to the distillation column 410 .

The first stage heat exchanger 416 is operated under conditions of 20 to 30 bar and -20 to -45 ℃, and the second stage heat exchanger 426 to be described later is 40 to 70 bar and -30 to -50 ℃ conditions. make it operational

The first stage heat exchanger 416 is to be operated higher than the triple point temperature of -49.4 ℃ to prevent crystallization of sulfur hexafluoride.

If sulfur hexafluoride crystallizes during operation, it causes problems such as clogging of pipes, so it is operated higher than the triple point temperature of -49.4℃.

On the other hand, the highly toxic substances mixed in the target gas obtained in the primary distillation column 410 may be removed in the secondary distillation column 420 .

The highly toxic material is SO ₂ F ₂ , S ₂ F ₁₀ , S ₂ F ₁₀ O etc.

The secondary distillation column 420 has a main body 423 having an inlet portion 421 through which a target gas is introduced, an outlet portion 422 formed on the upper portion, and a heating portion 425 formed at an inner lower portion of the main body 423 . ) and a first stage heat exchanger 426 formed at the upper end of the main body 423 , wherein the heating unit 425 is an electric heater or a steam line.

Preferably, the secondary distillation column 420 is operated 1 to 5 bar higher than the primary distillation column 410 .

In addition, based on 100 parts by weight of the target gas containing sulfur hexafluoride, the total content of highly toxic substances is operated at 0.5 to 1 parts by weight.

Specifically, the secondary distillation column 420 is operated so that the total content of the highly toxic substances in the sulfur hexafluoride product at the bottom of the distillation column does not exceed 1 wt% of the target gas.

The sulfur hexafluoride that has passed through the first and second distillation towers is finally stored in the storage tank 600 through a chemical dryer 450 for water removal.

While sequentially passing through the 1st and 2nd distillation towers, there is still around 12% sulfur hexafluoride in the target gas, and in order to completely separate it, a non-reactive gas (O ₂ , N ₂ , CF ₄ , etc.) should be removed.

Meanwhile, the target gas obtained from the primary distillation column 410 of the distillation unit 400 is transferred to a separation unit (not shown).

The separation unit includes a freezer (not shown) that freezes only sulfur hexafluoride to solidify, freezes only sulfur hexafluoride by freezing in the freezer, and freezes only sulfur hexafluoride and gases that are non-reactive at low temperatures, that is, non-reactive oxygen, nitrogen and carbon tetrafluoride. separate and remove

The freezing point of sulfur hexafluoride (SF ₆ ) is -64°C, the freezing point of O ₂ is -219°C, the freezing point of N ₂ is -210.8°C, and the freezing point of CF ₄ is -184°C, so -180 in the freezer. Freeze at a temperature of ℃ ~ -67℃.

Most of the sulfur hexafluoride gas recovered from the distillation unit 400 has a sulfur hexafluoride content of about 97%.

When using a freezer, the temperature is sufficiently lowered for 3 days or more to solidify the sulfur hexafluoride, and then the gas with a low freezing point can be removed and the sulfur hexafluoride gas can be separated.

The separated oxygen, nitrogen and carbon tetrafluorocarbons can be released into the atmosphere or collected and separated by a separate collection device.

On the other hand, the first scrubber 210 or the support device 10 mounted on the lower portion of the second scrubber 220; may include.

As shown in FIGS. 2 and 3 , the supporting device 10 is fitted with a fixing plate 11 installed on the ground, and the fixing plate 11 , and the lower surface of the first scrubber 210 or the second scrubber 220 . It is disposed between the moving plate 12 and the fixed plate 11 and the moving plate 12 supported on, characterized in that it comprises a plurality of buffer units 13 configured to elastically support the moving plate 12 do.

The plurality of buffer units 13 may include a core spring 131 , a first sub-spring 132 , a second sub-spring 133 , and an anti-vibration elastic body 134 .

The core spring 131 may be disposed at the center of the fixed plate 11 and the moving plate 12 , and may be configured to elastically support the moving plate 12 in the front-rear direction. For example, the core spring 131 may be implemented in the form of a compression coil diametrical spring.

The first sub springs 132 may be spaced apart from each other at equal intervals along the circumference of the core spring 131 , and may be configured to elastically support the moving plate 12 in the front-rear direction.

For example, the first sub spring 132 may be implemented in the form of a compression coil spring having a size smaller than that of the core spring 131 .

The second sub springs 133 are spaced apart at equal intervals along the circumference of the core spring 131 and elastically support the moving plate 12 along the front-rear direction at a position different from that of the first sub-spring 132 . can be configured. For example, the second sub spring 133 may be implemented in the form of a tension coil spring.

The vibration-proof elastic body 134 may be configured to accommodate the second sub spring 133 therein, and to support the fixed plate 11 and the moving plate 12 in the front-rear direction. For example, the vibration-proof elastic body 134 may be implemented with at least one of rubber, silicone, and urethane.

[Example]

A method of purifying high-purity sulfur hexafluoride using the above-described high-purity sulfur hexafluoride purification apparatus is as follows.

4 is a process flow diagram for a high-purity sulfur hexafluoride purification method according to the present invention.

As shown in Figure 4, the high-purity sulfur hexafluoride purification method according to the present invention,

Step 1 (S1) of supplying a target gas containing sulfur hexafluoride;

Step 2-1 (S2-1) of collecting the soluble gas component while passing the target gas through the first scrubber 210 to which the sodium hydroxide solution is sprayed;

2-2 step (S2-2) of collecting the soluble gas component by passing the target gas that has passed through the 2-1 step (S1) through the second scrubber 220 on which water is sprayed;

Step 3 (S3) of removing moisture by allowing the target gas that has passed through Step 2-2 (S2-2) to be dried while passing through a condenser or a chemical dryer filled with an adsorbent;

After the target gas from which moisture has been removed in step 3 (S3) is supplied to the primary distillation column 410 and heated, it is passed through a heat exchanger to separate oxygen, nitrogen and carbon tetrafluoride having a lower freezing point than sulfur hexafluoride. The 4-1 process (S4-1) of transporting and passing through the freezer of the separation unit (S4-3) to remove oxygen, nitrogen, and carbon tetrafluoride using the difference in freezing point, and to recover sulfur hexafluoride back to the primary distillation column 410 (S4-1) );

After the 4-1 process (S4-1), a 4-2 process (S4-2) of re-heating the target gas of the primary distillation column 410 in the secondary distillation column 420 to evaporate the poisonous material; and

After the 4-2 step (S4-2), the 5 step (S5) of filling the container with the dried target gas by passing it through the moisture drying unit;

Sodium hydroxide in step 2-1 (S1) has a low concentration of 5 to 10%.

The soluble gas component removed in step 2-1 (S2-1) or step 2-2 (S2-2) is hydrogen fluoride (HF), sulfuryl fluoride (SO ₂ F ₂ ), sulfur dioxide (SO ₂ ), Sulfurous acid (H ₂ SO ₃ ), thionylfluoride (SOF ₂ ), sulfur tetrafluoride (SF ₄ ), sulfur difluoride (SF ₂ ), disulfurdifluoride (S ₂ F ₂ ) and bispentafluoro It is any one or two or more selected from the group consisting of rosulphur oxide (Bispentafluorosulfur oxide: S ₂ F ₁₀ O).

Moisture removal in step 3 (S3) can be managed to less than 1 ppm of moisture through the gas treatment process of step 2 (S2).

A high-concentration sulfuric acid scrub can be used as a method of removing condensate, but most moisture is primarily removed through a condenser, a condensate removal facility, and secondly, a chemical dryer filled with chemical adsorbents such as molecular sieve, alumina, silica gel, etc. moisture is removed through

The chemical dryer is filled with an adsorbent selected from the group consisting of molecular sieves, alumina and silica gel.

The recovered sulfur hexafluoride gas from which the soluble gas and moisture have been removed by passing through step 3 (S3), that is, in the target gas, there are a significant amount of gases with little reactivity, such as O2, N2, CF4, which cannot be removed.

These less reactive gases are separated and then removed using the difference in boiling point.

Step 4-1 (S4-1) is heated in the primary distillation column with electricity or steam in the range of 20 to 30 bar, 50 to 100 ℃.

The first-stage heat exchanger (416-1) connected to the primary distillation column 140 is operated at 20-30 bar, -20 to -45 °C, and the second-stage heat exchanger (416-2) is 40 to 70 bar, - It is operated at 30~-50℃.

The gas that has passed through the second stage heat exchanger (416-2) is operated in a freezer at -180°C to -67°C for 2 to 4 days to freeze sulfur hexafluoride, and oxygen, nitrogen, and tetrafluoride, which are gases that are not reactive at low temperatures. removes carbon dioxide. Sulfur hexafluoride is recovered to the primary distillation column 410 again.

And most of the recovered sulfur hexafluoride gas has a sulfur hexafluoride content of about 97%, but sometimes a freezer can be used if it is recovered with low quality.

When using a freezer, the temperature can be sufficiently lowered for at least 3 days to solidify the sulfur hexafluoride, remove the gas with a low freezing point, and extract and separate only the sulfur hexafluoride gas.

Sulfur hexafluoride (SF ₆ ) has a freezing point of -64℃, the freezing point of O ₂ is -219℃, the freezing point of N ₂ is _-210.8 ℃, and the freezing point of CF4 is -184℃, so -180℃ in the freezer Freeze at a temperature of -67°C.

In step 4-2 (S4-2), the total content of the highly toxic substance is 0.5 to 1 part by weight based on 100 parts by weight of the target gas containing sulfur hexafluoride. ,

Very toxic substances are SO ₂ F ₂ , S ₂ F ₁₀ , S ₂ F 1 O O and _the like.

The highly toxic substances mixed in the target gas obtained in the primary distillation column 410 are removed in the secondary distillation column 420 .

Sulfur hexafluoride that has passed through the first and second distillation towers is stored in a storage tank 600 after passing through a chemical dryer 450 .

3 is a gas chromatography of a target gas purified according to the present invention.

Referring to this, the content of sulfur hexafluoride (SF ₆ ) was the highest, and carbon tetrafluoride> SO ₂ F ₂ > SO ₂ > CCl ₂ F ₂ > COS.

Although described in relation to the preferred embodiment, it will be readily recognized by those skilled in the art that various modifications and variations can be made without departing from the spirit and scope of the invention, and all such changes and modifications are intended to be included in the scope of the appended claims. belonging is self-evident.

100: supply unit 120: recovery-only container
200: pre-processing unit 210: first scrubber
220: second scrubber 300: moisture removal unit
380: chemical dryer 400: distillation unit
410: primary distillation column 420: secondary distillation column

Claims (9)

a supply unit for supplying a target gas containing sulfur hexafluoride;
A first scrubber for allowing the target gas to pass through a chamber to which the sodium hydroxide solution is sprayed so that the sodium hydroxide solution and the soluble gas component contained in the target gas are in contact and collected;
a pre-processing unit having a second scrubber for allowing the soluble gas component included in the target gas to contact and collect water while passing the target gas that has passed through the first scrubber through a chamber in which water is sprayed;
a water removal unit for passing the target gas that has passed through the pretreatment unit through a condenser or a chemical dryer filled with an adsorbent to remove the mixed water and maintain the water concentration at 0.1 to 1 ppm; and
Any one selected from the group consisting of a non-reactive gas or SO ₂ F ₂ , S ₂ F ₁₀ and S ₂ F ₁₀ O or a non-reactive gas consisting of oxygen, nitrogen and tetrafluorocarbon mixed in the target gas from which moisture has been removed by the water removal unit; or a distillation unit heating at high pressure and high temperature so as to be separated from sulfur hexafluoride by using the boiling point difference to remove 2 or more highly toxic substances;
includes,
The distillation unit includes a primary distillation column and a secondary distillation column for removing the poisonous substances mixed in the target gas obtained from the primary distillation column;
The primary distillation column or the secondary distillation column,
A main body having an inlet through which a target gas is introduced, an outlet formed at the upper portion, a heating unit formed at an inner lower portion of the main body, and a heat exchanger formed at an upper end of the main body, wherein the heating unit is an electric heater or a steam line High-purity sulfur hexafluoride purification apparatus, characterized in that. delete The method of claim 1,
The secondary distillation column is operated 1 to 5 bar higher than the primary distillation column,
The first-stage heat exchanger of the primary distillation column is operated at 20-30 bar, -20 to -45 °C, and the second-stage heat exchanger is operated at 40-70 bar, -30 to -50 °C,
High-purity sulfur hexafluoride purification apparatus, characterized in that the first-stage heat exchanger of the secondary distillation column is operated at 20 to 30 bar, -20 to -45 °C. 4. The method of claim 3,
Further comprising; a separation unit for separating sulfur hexafluoride mixed in the target gas obtained in the first-stage heat exchanger of the primary distillation column;
The separation unit includes a freezer for freezing and solidifying only sulfur hexafluoride,
High purity sulfur hexafluoride purification apparatus, characterized in that by freezing at -180 ° C to -67 ° C in the freezer to freeze only sulfur hexafluoride, and separating oxygen, nitrogen and carbon tetrafluoride that are non-reactive at low temperatures. a supply unit for supplying a target gas containing sulfur hexafluoride;
A first scrubber for allowing the target gas to pass through a chamber to which the sodium hydroxide solution is sprayed so that the sodium hydroxide solution and the soluble gas component contained in the target gas are in contact and collected;
a pre-processing unit having a second scrubber for allowing the soluble gas component included in the target gas to contact and collect water while passing the target gas that has passed through the first scrubber through a chamber in which water is sprayed;
a water removal unit for passing the target gas that has passed through the pretreatment unit through a condenser or a chemical dryer filled with an adsorbent to remove the mixed water and maintain the water concentration at 0.1 to 1 ppm; and
Any one selected from the group consisting of a non-reactive gas or SO ₂ F ₂ , S ₂ F ₁₀ and S ₂ F ₁₀ O or a non-reactive gas consisting of oxygen, nitrogen and tetrafluorocarbon mixed in the target gas from which moisture has been removed by the water removal unit; or a distillation unit heating at high pressure and high temperature so as to be separated from sulfur hexafluoride by using the boiling point difference to remove 2 or more highly toxic substances;
includes,
Including; a support device mounted on the lower portion of the first scrubber or the second scrubber;
The support device is disposed between a fixed plate installed on the ground, a moving plate fitted to the fixed plate and supported on the lower surface of the first or second scrubber, and the fixed plate and the moving plate, and elastically supporting the moving plate High-purity sulfur hexafluoride purification apparatus comprising a plurality of buffer units configured to do so. Step 1 of supplying a target gas containing sulfur hexafluoride;
Step 2-1 of collecting soluble gas components while passing the target gas through a first scrubber sprayed with sodium hydroxide solution;
a 2-2 step of collecting the soluble gas component by passing the target gas that has passed through the 2-1 step through a second scrubber sprayed with water;
a third step of removing moisture by allowing the target gas that has passed through step 2-2 to be dried while passing through a condenser or a dryer filled with an adsorbent;
The target gas from which moisture has been removed in step 3 is supplied to the primary distillation column and heated, and then passed through a heat exchanger to separate oxygen, nitrogen and carbon tetrafluoride having a lower freezing point than sulfur hexafluoride. a 4-1 step of passing through a freezer to remove oxygen, nitrogen, and carbon tetrafluoride using the difference in freezing point, and recovering sulfur hexafluoride back to the primary distillation column;
a 4-2 step of reheating the target gas of the first distillation column in a second distillation column after the 4-1 step to evaporate and remove the toxic substances; and
Step 5 of filling the container with the dried target gas by passing it through the moisture drying unit after step 4-2;
High-purity sulfur hexafluoride purification method comprising a. 7. The method of claim 6,
High-purity sulfur hexafluoride purification method, characterized in that the adsorbent in step 3 is selected from the group consisting of molecular sieve, alumina and silica gel. 7. The method of claim 6,
The 4-1 process is to heat with electricity or steam in the range of 20-30 bar, 50-100 ℃,
In step 4-2, the total content of the highly toxic substance is 0.5 to 1 parts by weight based on 100 parts by weight of the target gas containing sulfur hexafluoride,
The highly toxic substance is SO ₂ F ₂ , S ₂ F ₁₀ and S ₂ F ₁₀ O High-purity sulfur hexafluoride purification method, characterized in that at least one or two selected from the group consisting of. 7. The method of claim 6,
The soluble gas component in step 2-1 or step 2-2 is hydrogen fluoride, sulfuryl fluoride, sulfur dioxide, sulfurous acid, thionyl fluoride, sulfur tetrafluoride, sulfur difluoride, disulfurdifluoride and bispenta High purity sulfur hexafluoride purification method, characterized in that any one or two or more selected from the group consisting of fluorosulfur oxide.

Images