JP2000304438A - Method and device for manufacturing ultrahigh-purity gas - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the manufacture of ultrahigh-purity gas which does not need to be provided with a compressor for a product while making the most of the merit of a dual rectifying column, and besides can manufacture ultrahigh- purity gas. SOLUTION: The manufacture of ultrahigh-purity gas has a process of manufacturing ultrahigh-purity gas by refining preliminarily refined material fluid in order, using a dual rectifying column where a rectifying column 10 on low pressure side and a rectifying column 20 on high pressure side are arranged above and below through a reboil capacitor 14. In the process, a part of the fluid on the column bottom side more than the supply part of the material fluid of the rectifying column 10 on low pressure side is extracted while supplying the rectifying part of the rectifying column 10 on low pressure side with the material fluid. Then it is pressurized by a booster, and ultrahigh-purity substance is recovered from more column top side than the supply part of the pressurized fluid of the rectifying column 20 on high pressure side, while introducing the pressurized fluid into the rectifying part or the column bottom of the rectifying column 20 on high pressure side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a double rectification column in which a low-pressure rectification column and a high-pressure rectification column are arranged vertically via a reboil condenser, and the preliminarily purified raw material fluids are sequentially converted. The present invention relates to a production method and a production apparatus for producing an ultra-high-purity gas by refining, and is particularly useful for producing ultra-high-purity argon.

[0002]

2. Description of the Related Art Separation and purification of various gases using a rectification column (cryogenic separation) is a technique for separating low-temperature components from air and a technique for recovering useful gases from exhaust gases from various industrial equipment with high purity. It is used for such purposes. The basic principle of the rectification column is
Utilizing the phenomenon that the composition of gas and liquid in gas-liquid equilibrium is different, evaporation and condensation are performed while bringing the reflux liquid descending in the rectification section of the column and the vapor rising in the rectification section into gas-liquid contact. By repeating this, the high-boiling components are concentrated below the rectification section and the low-boiling components are concentrated above. At that time, a condenser and a reboiler are usually provided at the top and bottom of the rectification column, respectively, in order to lower the reflux liquid from the top of the column and generate reflux vapor from the bottom of the column.

[0003] When producing a higher-purity gas using such a rectification column, the raw material gas and the like are purified in the first rectification column, and the obtained high-purity gas and the like are converted into the second rectification column. , And a method for further purification is often employed. Accordingly, many methods for producing various forms of high-purity gas using a plurality of rectification columns have been filed.

[0004] Such techniques can be roughly divided into a type in which the first rectification column and the second rectification column are separately provided as single rectification columns, a type in which the first rectification column and the first rectification column (high-pressure rectification column) are provided. There is a type that uses a double rectification tower in which a second rectification tower (low-pressure rectification tower) is combined and combined. As the former type, for example, Japanese Patent Publication No. 7-85761 discloses the first type.
A part of the gas at the bottom of the rectification column is extracted from the feed portion of the raw material fluid of the rectification column, and the liquid extracted from the bottom of the second rectification column is guided to the bottom of the second rectification column. While returning to
A method of recovering ultra-high purity gas such as argon from the top of the second rectification column is described.

[0005] However, the above-mentioned method can produce an ultra-high-purity gas. However, since two single rectification columns are separately provided, the apparatus is different from the type using a double rectification column. There are disadvantageous aspects such as complication, cost increase and installation space increase.

Therefore, various types using a double rectification column have been proposed. Such a double rectification column generally comprises
The low-pressure rectification tower and the high-pressure rectification tower are arranged vertically via a reboil condenser, and the purified gas or the bottom liquid is withdrawn from the high-pressure rectification tower arranged below and used for pressure adjustment. Via the above-mentioned valve to the rectification section of the low-pressure rectification column arranged on the upper side for further purification.

[0007]

However, in the above-mentioned method, since the product pressure is lower than the raw material supply pressure, it is usually necessary to further provide a compressor for the product. There was a problem that it was easily contaminated.

Accordingly, an object of the present invention is to provide a super-high-pressure column capable of controlling the pressure without providing a product compressor while utilizing the advantages of the double rectification column, and capable of producing an ultra-high-purity gas. An object of the present invention is to provide a method for producing a purity gas.

Japanese Patent Application Laid-Open No. 8-14736 discloses that
After compressing the gas extracted from the top of the low pressure rectification column, it is described that a method of conducting purification by introducing the medium pressure rectification column,
The compression is performed in order to recycle air of relatively low purity, and has a different purpose and technical idea from the pressurization in the present invention.

[0010]

The above object can be achieved by the present invention as described below. That is, the present invention uses a double rectification column in which a low-pressure rectification column and a high-pressure rectification column are arranged vertically via a reboil condenser, and sequentially purifies preliminarily purified raw material fluids. In the method for producing an ultra-high-purity gas having a step of producing a high-purity gas, while supplying the raw material fluid to a rectification section of the low-pressure rectification tower, a supply section of the raw fluid of the low-pressure rectification tower After extracting a part of the fluid at the bottom of the column, the pressure is increased by a pressurizer, and while the pressurized pressurized fluid is introduced into the rectification section or the bottom of the high-pressure rectification column, the high-pressure rectification is performed. An ultra-high-purity substance is recovered from the top of the distillation column from the supply section of the pressurized fluid. The “ultra-high-purity gas” refers to a gas having a higher purity than a gas purified by one rectification column, and has only a relative meaning.

In the above, by providing various recycle paths, a heat source and a cooling source of the reboiler and the condenser can be suitably generated, but the bottom liquid of the high-pressure rectification column is withdrawn and reduced in pressure. After being introduced into the refrigerant storage part of the condenser of the low-pressure rectification column and the gas vaporized in the refrigerant storage part is compressed by the compressor, a recycle path is supplied to the bottom of the high-pressure rectification tower as reboil gas. In addition, when pressurizing the fluid extracted from the low-pressure rectification column, it is preferable to supply and mix the fluid upstream of a compressor in the recycle path via a valve.

In the above, the raw material fluid may be preliminarily purified so as not to hinder rectification, but the raw material fluid is argon having a purity of 95% by volume or more and having a lower boiling point. And a substance having a higher boiling point as impurities.

On the other hand, the production apparatus of the present invention has a low-pressure section having a rectification section having a supply section for a raw material fluid in the middle, and a condenser for liquefying the gas from the rectification section and supplying the liquefied gas partially as a reflux liquid. Side rectification column, disposed below the low pressure side rectification column, high pressure side rectification column having a rectification section, interposed between the low pressure side rectification column and the high pressure side rectification column, A double rectification column equipped with a reboil condenser having a recovery section for recovering ultra-high-purity products as unliquefied gas, and the bottom liquid of the high-pressure rectification column is withdrawn and reduced in pressure, and the low-pressure rectification column is removed. A recycle path, which is introduced into a refrigerant storage part of a condenser of the condenser, and a gas vaporized in the refrigerant storage part is compressed by a compressor, and then supplied as a reboil gas to the bottom of the high-pressure rectification column. Part of the fluid on the bottom side of the section, through a valve, It is obtained by a derivation path for mixing supplied to the flow side.

According to the present invention, after extracting a part of the fluid from the low-pressure rectification column, the fluid is pressurized by a booster and introduced into the high-pressure rectification column. The product pressure can be adjusted mainly by this pressure booster, while maintaining a favorable pressure balance in both towers, for the most part to determine. At that time, while supplying the raw material fluid to the rectification section of the low-pressure rectification column, a part of the fluid on the bottom side is extracted, and then introduced into the rectification section or the bottom of the high-pressure rectification column. ,
In order to recover ultra-high-purity substances from the top side, rectification is performed sequentially in the low-pressure rectification column and the high-pressure rectification column, so that ultra-high-purity products can be recovered, and as described above. Since a product compressor is not required, a product with higher purity can be obtained.

As a result, while utilizing the advantages of the double rectification column, the pressure can be adjusted without providing a product compressor, and an ultra-high purity gas can be produced. Could be provided.

In addition, the above-mentioned recycle path is constituted, and when the fluid extracted from the low-pressure side rectification column is pressurized, the fluid is supplied to a recycle path upstream of the compressor through a valve and mixed. In this case, the recycle path has a role of a reboiler of the high-pressure rectification tower, and can suitably generate a cooling source for the condenser of the low-pressure rectification tower. At that time, in pressurizing the fluid extracted from the low-pressure side rectification column, the fluid is supplied and mixed to the upstream side of the compressor in the recycle path via a valve,
A compressor can be used as a pressure booster for pressurization, and the flow rate can be adjusted by a valve. Therefore, the balance of the rectification operation in both towers can be suitably adjusted.

Further, when the raw material fluid is argon having a purity of 95% by volume or more and contains a substance having a lower boiling point and a substance having a higher boiling point as impurities, the substance having a lower boiling point may be used. Since it can be almost completely removed in the low-pressure rectification column, ultra-high-purity argon can be produced by removing higher boiling substances in the high-pressure rectification column. Further, since the substance having a low boiling point is almost completely removed in the low-pressure rectification column, the purity of the product is hardly reduced even if the above-mentioned recycling route is adopted.

On the other hand, according to the production apparatus of the present invention, due to the above-mentioned effects, while utilizing the advantages of the double rectification column,
There is no need to provide a product compressor, and ultra-high-purity gas can be produced. Also, the recycling route
A booster that has a role of a reboiler for the high-pressure rectification tower, can suitably generate a cooling source for the condenser of the low-pressure rectification tower, and further pressurizes the fluid extracted from the low-pressure rectification tower. Can also be used as a compressor.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below in the order of the first to third embodiments of the present invention and an argon recovery facility using the third embodiment.

(First Embodiment) As the first embodiment of the present invention, the simplest embodiment as shown in FIG. 1 will be exemplified.

The raw material fluid is supplied to the lower pressure side rectification column 10 from the path L1.
Prior to this, preliminary purification, cooling, compression and the like are usually performed by equipment not shown. In the pre-purification, components that are difficult to remove in the rectification column and impurities such as solid components such as dust are removed, and a purification operation is performed in advance to make the raw material considerably high purity. The cooling and the compression are performed to adjust the temperature and the pressure of the raw material fluid to a range suitable for supplying to the rectification column 10 and are usually compressed to a pressure slightly higher than the supply portion of the low-pressure rectification column 10. , Is cooled to near the liquefaction temperature at that pressure.

A rectification section 12 is provided on the top side (upper side) of the supply section of the raw material fluid in the low pressure side rectification tower 10, and on the bottom side (lower side) of the supply section, A rectification section 11 is provided. The types of the rectification units 11 and 12 include a shelf type and a filling type, and any type can be adopted. Rectification unit 1
In 1 and 12, the evaporating and condensing are repeated while the descending reflux liquid and the ascending vapor come into gas-liquid contact, so that the rectification section 1
Products and high-boiling impurities are concentrated below 1, 12 and low-boiling impurities are concentrated above.

At the bottom of the low-pressure rectification column 10, ie, at the boundary between the low-pressure rectification column 10 and the high-pressure rectification column 20 of the double rectification column, the reboiler of the low-pressure rectification column 10 Side rectification tower 20
A reboil condenser 14 which is also used as a condenser is provided. In the reboil condenser 14, the gas at the top of the high-pressure rectification column 20 is used as a heat source,
At the same time, a part of the top gas of the high-pressure rectification column 20 is condensed while using the bottom liquid of the low-pressure rectification column 10 as a cooling source while the bottom liquid of the column 0 is reboiled. At that time, the low pressure side rectification column 10
Is discharged from the path L2 via the valve 23.

On the other hand, a condenser 13 is provided at the top of the low-pressure rectification column 10, and a part of the top gas is liquefied by a refrigerant introduced through a path L5 to form a reflux liquid, while the remaining part is liquefied. The exhaust gas is exhausted from the path L7 via the valve 15. A part of the refrigerant stored in the refrigerant storage part of the condenser 13 evaporates and is discharged from the path L6 via the valve 16. In addition, the type of the condenser 13, the refrigerant, the cooling source, and the like may be any.

In the present invention, after the raw material fluid is purified in the low-pressure rectification column 10 as described above, the obtained high-purity fluid is guided to the high-pressure rectification column 20 for further purification. After a part of the fluid on the bottom side is extracted from the feed portion of the raw material fluid of the rectification column 10, the fluid is pressurized by a pressure booster, and the pressurized fluid is pressurized and the pressurized fluid is supplied to the bottom of the high-pressure rectification column 20 (or ). The fluid extracted from the bottom of the tower by the derivation route L8 is
Although a gas or a reflux liquid may be used, this embodiment shows an example in which the gas at the bottom of the tower is extracted and the gas is compressed using a compressor 31 as a pressure booster.

The pressurized fluid introduced from the path L9 flows through the rectification section 21 in the high-pressure rectification tower 20 in the same manner as in the low-pressure rectification tower 10, and the reflux liquid descending while the gas component rises. By repeating evaporation and condensation while contacting the gas and the liquid, the product is concentrated on the upper side of the rectifying section 21 and the high boiling point impurities are concentrated on the lower side. Therefore, the unliquefied gas is transferred from the top of the high pressure side rectification column 20 via the reboil condenser 14 to the path L10.
By extracting with, ultra-high purity product fluid (product gas)
Can be recovered.

A reboiler 2 is provided at the bottom of the high-pressure rectification column 20.
2 is provided, the bottom liquid is withdrawn from the path L11 at the bottom of the tower, evaporated and returned to the bottom of the tower from the path L12 as reboil gas. At that time, part of the bottom liquid was
Via the path L13. In addition, reboiler 2
The type 2 and the heat source may be any.

Next, the relationship between the pressures of the respective parts in the above-described apparatus will be described. The pressure in the low-pressure rectification column 10;
The pressure in the high-pressure rectification column 20 is set to a pressure that generates a pressure difference corresponding to a design temperature difference between the high-temperature side and the low-temperature side of the reboil condenser 14. Therefore, since the outlet pressure of the booster can be set independently of the above pressure difference,
The product pressure can be determined by the outlet pressure, and the product pressure is slightly lower than the outlet pressure.

(Second Embodiment) As a second embodiment of the present invention, as shown in FIG. 2, a low-pressure rectification column 10 according to the first embodiment in which a rectifying section 18 is further added is exemplified. Note that the other parts are the same as in the first embodiment, and thus only different parts will be described.

The rectifying section 18 is provided below the rectifying section 11 (to the bottom of the tower) and below the connection with the lead-out path L8 (to the bottom of the tower). Therefore, in the first embodiment, the gas having a composition close to the bottom liquid of the low-pressure rectification column 10 is
On the other hand, in the second embodiment, a gas having a low content of high-boiling-point impurities is extracted in the lead-out route L <b> 8 by the amount of the rectification unit 18 in the second embodiment. . As a result, in the high-pressure rectification column 20, it becomes easy to produce a product having less high boiling point impurities.

(Third Embodiment) As a third embodiment of the present invention, an embodiment in which a recycling path, a heat exchanger, and the like are added to the first embodiment as shown in FIG. 3 will be exemplified. In addition,
Since the basic parts are the same as those in the first embodiment, only the added or changed parts will be described.

This embodiment is similar to the reboiler 2 of the first embodiment.
In place of 2, a recycling path having a function of supplying a refrigerant to the condenser 13 is provided, and the gas extracted from the low-pressure rectification column 10 is pressurized by using the recycling path, Is introduced. In this recycling path, first, the bottom liquid of the high-pressure side rectification column 20 is withdrawn from the path L11, decompressed by the expansion valve 36, and introduced into the refrigerant storage section of the condenser 13. At this time, the insufficient cold is replenished by supplying liquid argon or the like from the path L5. The gas vaporized in the refrigerant storage part of the condenser 13 is preheated in the heat exchanger 32 via the path L6,
And a small amount is discharged from the upstream side of the compressor 39 via the valve 35 so that the high-boiling components are not concentrated. After being compressed, the recycle gas is again introduced into the heat exchanger 32, cooled, and then supplied as reboil gas from the path L9 to the bottom of the high-pressure rectification column 20.

At this time, the lead-out route L from the low-pressure rectification column 10
The gas extracted through 8 is heated to near normal temperature by the heat exchanger 32 and then supplied and mixed via the valve 34 to the upstream side of the compressor 33 in the recycle path. Thus, the gas can be pressurized by using the compressor 33 in the recycling path, and the pressure booster for pressurization can be shared by the compressor. Moreover, since the flow rate can be adjusted by the valve 34, the balance of the rectification operation in both towers can be suitably adjusted.

By controlling the storage amount and pressure of the liquid refrigerant in the condenser 13, the capacity for condensation can be easily adjusted. Further, since high boiling point impurities are easily concentrated in the liquid refrigerant, it is possible to provide a discharge path (not shown), extract a part of the liquid refrigerant, vaporize the liquid refrigerant, and then discharge it.

On the other hand, after the raw material fluid is cooled in the heat exchanger 32, it is supplied to the low-pressure rectification column 10 through a path L1.
The same rectification operation as in the first embodiment is performed. Thereafter, as described above, the fluid supplied from the low-pressure rectification column 10 to the high-pressure rectification column 20 via the recycle path is further purified in the rectification section 21 of the high-pressure rectification column 20, Via the top reboil condenser 14, it is recovered as ultra-high-purity product fluid (product gas) in the path L10. The recovered product gas is discharged after being cold-recovered in the heat exchanger 32. At that time, it is desirable to return a part of the product gas to the feed path of the feed fluid via the valve 37 to maintain the feed rate of the double rectification column at or above the minimum capacity. In this case, a means for detecting the flow rate or the like may be provided in the supply path of the raw material fluid, and the opening degree of the valve 37 may be controlled based on the detection result.

Among the above-mentioned facilities, those which require heat insulation from the outside air are housed in a cold box as shown in FIG.

By the way, in the above-mentioned embodiment, the purity of 99.999% by volume is obtained by using 95% by volume of argon as a raw material.
When the above product argon is produced at a pressure of 8.90 barA, for example, the outlet side pressure of the compressor 33 is 9.25 bar.
rA, the pressure at the junction of the outlet path L8 is 7.44 bar
A, the pressure at the connection of path L6 is set to 3.74 barA. However, these pressures can be appropriately changed according to the product pressure, the raw material pressure, and the conditions of the rectification operation.

(Argon Recovery Facility) FIG. 4 shows an example of a flow sheet of an argon recovery facility using the manufacturing method of the third embodiment. This equipment is generally composed of a single crystal silicon pulling apparatus 1, a preliminary purification unit 6, a cooling unit 40, a decarburization drying unit 50, a low-temperature purification unit 60, and a high-purity argon tank 90. The apparatus shown in FIG.

The single crystal silicon pulling apparatus 1 is supplied with high purity argon gas (boiling point -186 ° C.) as a shielding gas from a pipe P1. The gas (hereinafter, referred to as “argon exhaust gas”) discharged from the single crystal silicon pulling apparatus 1 by the vacuum pump ₂ includes H ₂ and N in addition to dust.
₂ , O ₂ , CO, CO ₂ , and hydrocarbons are contained as impurities. Hydrocarbons are primarily CH ₄ below 50VolPPM. In FIG. 4, for simplicity,
Although only one single crystal silicon pulling device 1 and one vacuum pump 2 are shown, a plurality of devices are actually arranged in parallel. Since the amount of the argon exhaust gas discharged from the single-crystal silicon lifting device 1 changes according to the number of operating single-crystal silicon lifting devices 1 and the like, the argon exhaust gas is temporarily stored in the gas holder 3.

The argon exhaust gas stored in the gas holder 3 is introduced into the preliminary purification unit 6 by the compressor 5 via the suction filter unit 4. At that time, the dust is removed from the argon exhaust gas by the suction filter unit 4. Further, in order to supplement the amount of oxygen required in the subsequent oxidation step, a small amount of air is added to the argon exhaust gas discharged from the suction filter unit 4 via the pipe P31. The argon exhaust gas is pressurized by the compressor 5 to a pressure of about 3.5 to 9.0 kg / cm ² G. The value of this pressure is set according to the optimal operating conditions in the subsequent decarburization drying step, the argon product pressure, and the like.

The argon exhaust gas leaving the compressor 5 is:
It is introduced into the pre-purification unit 6. Preliminary purification unit 6
Has a carbon monoxide oxidizing tower 7 and a deoxo tower 8, and H ₂ for deoxygenation is supplied to the deoxo tower 7 from a hydrogen gas source outside the system via a pipe P32. Argon exhaust gas is
First, CO is introduced into the carbon monoxide oxidizing tower 7 and CO is oxidized by the Pd catalyst to change to CO ₂ . Next, after H ₂ is added, it is introduced into the deoxo tower 8. Deoxo Tower 8
In the above, the reaction between O ₂ and H ₂ is promoted by the Pd catalyst, and O ₂ is converted to H ₂ O. Note that the flow rate of H ₂ added in the deoxo tower 8 to remove O ₂ almost completely is set excessively to the theoretically required amount.

The argon gas (hereinafter, referred to as “deoxo argon gas”) that has exited the preliminary purification facility 6 is introduced into the cooling unit 40. The cooling unit 40 includes a water-cooled heat exchanger 41, a separator 43, a heat exchanger 45 having a refrigerator 46, and a water separator 47. The deoxo argon gas is first introduced into the heat exchanger 41 and cooled to about 40 ° C. The cooled deoxo argon gas is introduced into the separator 43 to separate condensed moisture. Next, the deoxo argon gas is supplied to the heat exchanger 4.
5. Cool to about 10 ° C. The cooled deoxo argon gas is introduced into the water separator 47, and the condensed water is further separated.

The deoxo argon gas leaving the cooling unit 40 is introduced into the decarburization drying unit 50. The decarburization drying unit 50 includes a pair of adsorption towers 51 and 52 used alternately. The adsorption towers 51 and 52 contain H ₂
Fillers such as alumina and molecular sieves are filled to adsorb O and CO ₂ . Since the pair of adsorption towers 51 and 52 are operated using the principle of pressure-casing adsorption (PSA) or temperature swing adsorption (TSA), a pipe P for supplying nitrogen gas for regeneration of the adsorbent is used.
50 and a discharge pipe P51 are connected.

The deoxo argon gas exiting the decarburization drying unit 50 has a temperature of about 10 ° C. and a pressure of about 6.4 kg / cm ^2.
At G, it is introduced into the heat exchanger 32 of the low-temperature purification section 60. The composition at that time is, for example, N ₂ : 2.0 vol%, CH ₄ :
0.005vol%, H _2: with 0.5 vol%, the remainder being argon.

In the low-temperature purification section 60, the rectification operation as in the third embodiment described above is performed, and an ultra-high purity argon gas (purity of 99.999% or more) is recovered as a product gas. At that time, high-purity liquid argon as a cold source,
It is supplied from a tank 90. The product gas is introduced into the product filter facility 70 through the pipe P15, and is dust-removed to a level of cleanliness required for introduction of the single crystal silicon lifting apparatus 1, and then supplied to the single crystal silicon lifting apparatus 1 again. . Note that the single crystal silicon pulling apparatus 1 is initially or as a shortage.
High-purity argon gas supplied to the tank 90
Is introduced into the evaporator 95 through the valve V8 and gasified.

It is desirable that a part of the above-mentioned product gas be returned to the outlet side of the compressor 5 through the valve 38 so that the raw material supply amount is maintained at least the minimum capacity of the double rectification column. In that case, the valve 37 in the low-temperature purification section shown in FIG.
It is not necessary to provide the path.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram illustrating an example of an apparatus used in a manufacturing method according to a first embodiment.

FIG. 2 is a schematic configuration diagram illustrating an example of an apparatus used in a manufacturing method according to a second embodiment.

FIG. 3 is a schematic configuration diagram illustrating an example of an apparatus used in a manufacturing method according to a third embodiment.

FIG. 4 is a schematic configuration diagram showing an example of an argon recovery facility using a third embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Low pressure rectification tower 11 Rectification part 12 Rectification part 13 Condenser 14 Reboil condenser 20 High pressure rectification tower 21 Rectification part 31 Compressor (Pressure booster) 33 Compressor (Pressure riser) 34 Valve 36 Expansion valve L8 derivation route

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Takao Yamamoto No. 16 Niijima, Harima-cho, Kako-gun, Hyogo Japan Air Liquide Harima Technical Center F-term (reference) 4D047 AA01 AB04 CA03 DA06

Claims (4)

[Claims] An ultrahigh-purity raw material fluid is purified by sequentially purifying raw material fluids that have been preliminarily purified using a double rectification column in which a low-pressure rectification column and a high-pressure rectification column are vertically arranged via a reboil condenser. In the method for producing an ultra-high-purity gas having a step of producing a purity gas, while supplying the raw material fluid to the rectification section of the low-pressure rectification column, from the supply section of the raw fluid in the low-pressure rectification column After extracting a part of the fluid on the bottom side of the tower, pressurize with a pressure booster,
While introducing the pressurized pressurized fluid into the rectification section or the bottom of the high-pressure rectification column, the ultrahigh-purity substance is supplied from the top of the high-pressure rectification column from the supply section of the pressurized fluid to the high-pressure rectification column. A method for producing an ultra-high-purity gas, comprising recovering the gas. 2. A bottom liquid of the high-pressure rectification column is withdrawn, decompressed, introduced into a refrigerant storage section of a condenser of the low-pressure rectification tower, and a gas vaporized in the refrigerant storage section is compressed by a compressor. After the compression, a recycle path is supplied to the bottom of the high-pressure rectification tower as reboil gas, and the fluid extracted from the low-pressure rectification tower is pressurized. 2. The production method according to claim 1, wherein the mixture is supplied to the upstream side of the compressor in the path. 3. The production method according to claim 1, wherein the raw material fluid is argon having a purity of 95% by volume or more, and contains a substance having a lower boiling point and a substance having a higher boiling point as impurities. Method. 4. A low-pressure rectification column having a rectification section having a supply section for a raw material fluid in the middle, a condenser for liquefying gas from the rectification section and supplying a part of the gas as a reflux liquid, A high-pressure rectification tower having a rectification section, which is disposed below the low-pressure rectification tower, is interposed between the low-pressure rectification tower and the high-pressure rectification tower, and liquefies ultra-high-purity products. A double rectification column equipped with a reboil condenser having a recovery section for recovering as a gas, a bottom liquid of the high-pressure rectification tower is withdrawn and depressurized, and a refrigerant storage section of a condenser of the low-pressure rectification tower And a recycle path for supplying gas as a reboil gas to the bottom of the high-pressure rectification column after compressing the gas vaporized in the refrigerant storage section with a compressor, and a fluid on the bottom side from the supply section of the raw material fluid. To supply and mix a part of the gas to the upstream side of the compressor in the recycle path via a valve Apparatus for producing ultra-high purity gas and a road.