JPH07133982A - Method and apparatus for preparing high purity argon - Google Patents

Abstract

PURPOSE:To provide a method and an apparatus for preparing a high purity argon without the use of a hydrogenation/deacidification process in an ordinary argon purifying method and further without the use of a high purity argon tower. CONSTITUTION:Air is compressed, refined, cooled, and introduced into a main fractionating tower 51 comprising at least one tower to take out oxygen and/or nitrogen, and argon stock gas with oxygen contents of about several ppm is introduced into the main fractionating tower 51 and is further introduced into an argon fractionating tower 53 of the theoretical stage number of 100 or more preferably of 160 or more for fractionation. Argon gas including nitrogen is taken out by adjusting its amount from a tower top, and high purity fractionated gas or liquid argon is taken out from a portion of the tower below several states or several tens of stages from the tower top and liquified oxygen is taken out from a tower bottom. Refined gas or liquefied argon is further fractionated through adsorption or gettering. In the argon fractionating tower the amount of a reflux is controlled, and the purity of the fractionated argon and the amount of the fractionation of the same are controlled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for producing high-purity argon together with oxygen and nitrogen by compressing, purifying and cooling air and liquefying and rectifying air.

[0002]

2. Description of the Related Art FIG. 6 shows an example of a conventional method for collecting high-purity argon by a cryogenic air separation method. From the middle stage of the low pressure column (upper column) of the double rectification column 1, substantially 5 to 15% of argon and a trace amount of nitrogen raw material gas of argon are extracted into the pipe 2, and the lower part of the crude argon column 3 is used. Will be introduced to. A condenser 4 is provided above the crude argon column 3, and liquefied air extracted from the lower part of the intermediate pressure column (lower column) of the double rectification column 1 and having a low pressure by the expansion valve 5 is Tube 6
Has been introduced as a cold source from. As a result, the raw material gas that has risen in the crude argon column 3 is liquefied in the condenser 4 and becomes a reflux liquid, and liquefaction rectification is performed with the raw material gas that rises in the column, and 90% of argon is supplied from the top of the column. As described above, crude argon having a composition of oxygen number% or less and nitrogen number% or less is extracted to the pipe 7. On the other hand, from the bottom of the crude argon column 3, liquefied oxygen is led to the pipe 8 and returned to the upper column, and the gas obtained by vaporizing the liquefied air in the condenser 4 is introduced into the upper column by the pipe 9.

The crude argon discharged to the pipe 7 passes through the heat exchanger 10 and cools the return gas to a substantially atmospheric temperature.
It is sent from a pipe 11 to a compressor 13 via a gas holder 12 which also serves as a storage tank and a buffer. The crude argon gas compressed by the compressor 13 to a pressure necessary for the subsequent process is discharged into the pipe 14, and the oxygen content in the crude argon is removed by the oxygen / hydrogen reaction from the hydrogen supply facility 15 through the pipe 16. After sufficient hydrogen has been added, the hydrogen is introduced into the catalyst cylinder 17. The catalyst cylinder 17 is filled with a catalyst that accelerates the oxygen-hydrogen reaction, and the temperature is raised to 300 ° C. to 400 ° C., so that the reaction proceeds. As a result, oxygen in the crude argon reacts rapidly with the added hydrogen to produce water. The crude argon gas (deoxygenated argon gas) containing the produced water is sent to the water separator 19 through the pipe 18 after being cooled, and is further introduced into the switchable dryer 21 through the pipe 20. In this drying step, the deoxygenated argon gas from which the generated water has been removed is guided to the heat exchanger 10 through the pipe 22, cooled, and introduced from the pipe 23 to the middle stage of the high purity argon column (denitrification column) 24. It

A reboiler 26 using a medium-pressure nitrogen supplied from the lower column of the double rectification column 1 through a pipe 25 as a heating source is provided below the denitrification column 24, and a condenser is provided above the denitrification column 24. 31 is provided. The condenser 31 is condensed and liquefied by the reboiler 26, and then expanded by a valve 27 so that the tube 2
The liquefied nitrogen supplied from No. 8 and the liquefied nitrogen supplied from the lower column of the double rectification column 1 via the pipe 29 and the valve 30 are supplied. The denitrification tower 24 rectifies the deoxygenated argon introduced from the pipe 23, separates a mixed gas of nitrogen and hydrogen at the top of the tower and discharges it from the tube 32, and at the bottom of the tower, high-purity liquefied argon. The high-purity liquefied argon, which is to be separated, is collected through a pipe 33. The pipe 34 is
This is a discharge pipe for nitrogen gas that is vaporized as a result of being cooled by the condenser 31, and joins with a pipe 35 for nitrogen gas that is led out from the top of the upper column of the double rectification column 1.

As described above, in the conventional high-purity argon production process, high-purity argon has been obtained through a very complicated and numerous process. Therefore, as a method for improving the above disadvantages of the conventional argon purification method, the number of theoretical argon columns is set to 150 theoretical stages or more and the oxygen in the crude argon is purified to 1 ppm or less, thereby omitting the catalyst deoxidizing step. The method of doing is proposed.

[0006]

However, in the case of a method having a hydrodeoxidation step using a copper or nickel catalyst, this hydrodeoxidation step requires expensive and dangerous hydrogen, and a drying step is required. As a result, the process is complicated and the operation becomes complicated, and the apparatus becomes expensive, and a highly pure argon column mainly for purging hydrogen and nitrogen is required after the hydrodeoxidation step.

[0007] Further, a method has been proposed in which the hydrodeoxidation step is omitted by increasing the number of theoretical plates of the crude argon column to 150 or more, but this method also has the above-mentioned high purity argon for removing nitrogen. I need a tower.

[0008] Therefore, an object of the present invention is to provide a method for producing high-purity argon by omitting the hydrodeoxidation step and further without using a high-purity argon column.

[0009]

In order to achieve the above-mentioned object, the method for producing high-purity argon of the present invention comprises compressing, purifying and cooling air and introducing it into at least one main rectification column. While producing oxygen and / or nitrogen, an argon raw material gas is derived from the main rectification column, and the theoretical plate number is 100.
It is introduced into an argon purification column having at least 160 stages, preferably at least 160 stages, and rectification is performed, and an argon gas containing nitrogen is discharged from the top of the column by adjusting the amount thereof and higher than several to ten or more stages below the top of the column. Purified gas or liquid argon having a purity is produced, and liquefied oxygen is led out from the bottom of the column.

Further, in the method of the present invention, the nitrogen content of the argon source gas discharged from the main rectification column is 100 ppm.
It is preferably 50 ppm or less, more preferably 5 pp or less.
m or less, the argon purification column is a packed column filled with a regular packing material or an irregular packing material, and the amount of cold supplied to the condenser of the argon purification column is at least 30 times the amount of purified argon withdrawn. The amount of gas that can be liquefied, the cold source supplied to the condenser of the argon purification column is oxygen-enriched liquefied air derived from the lower column of the main rectification column, liquefied nitrogen, or liquefied gas from the attached liquefaction cycle. The oxygen content of the purified argon derived from the argon purification column is 10 ppm or less, preferably 1 ppm or less, and the purified liquid argon or the gas argon derived from the argon purification column is vaporized or heated. , Further raising the reaction temperature with the getter, and purifying by reacting with the getter to remove a trace amount of nitrogen and oxygen contained,
Purified liquid derived from the argon purification column As a liquid or after vaporizing argon, further purifying by passing through an adsorption bed to remove a trace amount of nitrogen and oxygen contained, and a purified gas derived from the argon purification column. It is characterized in that the argon or the vaporized argon is kept at a low temperature or heated to a normal temperature, and then passed through an adsorption bed for further purification to remove a small amount of contained nitrogen and oxygen.

The apparatus for producing high-purity argon according to the present invention comprises a main rectification column comprising at least one column for producing oxygen and / or nitrogen by introducing compressed, purified and cooled raw material air, and the main rectification column. A route for deriving the argon raw material gas from the distillation column,
An argon purification column comprising a packed column having an equivalent theoretical plate number of 100 stages or more, preferably 160 stages or more, in which an argon raw material gas is introduced to carry out rectification, and a route for deriving an argon gas containing nitrogen from the top of the argon purification column, Means for adjusting the amount of nitrogen-containing argon gas discharged, a route for producing purified gas or liquid argon of high purity from a few theoretical stages to a few dozen stages below the tower top, and liquefied oxygen from the bottom of the column It is characterized by having a route to. Further, in the apparatus of the present invention, a route for leading out the argon raw material gas from the main rectification column is provided at a position where the nitrogen content in the argon raw material gas is 50 ppm or less, preferably 5 ppm or less, and the argon purification An analyzer for detecting the oxygen concentration in the purified argon in the purified argon derivation path of the tower, and a means for detecting and adjusting the derivation flow rate of the purified argon in the purified argon derivation path of the argon purification tower are provided, and the oxygen concentration analyzer. A controller for controlling the purified argon derivation flow rate control means by a signal from is provided, and an analyzer for detecting the oxygen concentration in the purified argon derived from the argon purification column,
And a means for detecting and adjusting the amount of cold liquefied gas in the argon purification tower condenser, and controlling the amount of cold liquefied gas and / or the pressure such as pressure in the argon purification tower condenser by a signal from an oxygen concentration analyzer. It is characterized in that the argon purifying column is automatically controlled by providing a controller for controlling.

Furthermore, the air is compressed, purified and cooled,
Oxygen and / or oxygen is introduced into the main rectification column consisting of at least one column.
Alternatively, while producing nitrogen, an argon raw material gas is discharged from the main rectification column and introduced into an argon purification column composed of a packed column having a column length of 10 m or more for rectification, and nitrogen containing argon is supplied from the top of the column. The gas was discharged by adjusting its amount, and was discharged from the top of the tower 6
Purified argon having a purity of 0 cm to 300 cm or less is produced, and liquefied oxygen is discharged from the bottom of the column. The route for discharging the argon raw material gas from the main rectification column has a nitrogen content in the argon raw material gas. Is 50 ppm or less, preferably 5 ppm or less.

[0013]

[Operation] By performing air separation with the above configuration,
High-purity argon can be produced by basically providing only one argon purification column. Further, by passing the high-purity argon through a getter reaction column or an adsorption bed, it is possible to produce ultra-high-purity purified argon from which the amount of the impurities has been removed.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in more detail below with reference to the embodiments shown in the drawings. FIG. 1 shows an embodiment of the present invention, in which oxygen is mainly contained as a main component from the middle stage of the low-pressure column (upper column) 51b of the main rectification column (double rectification column) 51 and contains argon. 5 to 15%, nitrogen 100ppm or less, preferably 50ppm or less, more preferably 5p
Argon raw material gas of pm or less is extracted into the conduit 52 and introduced into the lower part of the argon purification tower 53.

The argon source gas extracted from the low-pressure column 51b usually has a composition of oxygen as a main component and a minute amount of 5 to 15% argon and 1% or less nitrogen.
It is derived from the position where the argon content is the highest. However, according to the present invention, by configuring the argon purification column 53 with 100 or more theoretical plates, it is possible to sufficiently separate argon / oxygen without necessarily extracting the argon source gas from the position where the argon concentration is the highest. This is the focus.

Therefore, the argon raw material gas discharged from the main rectification column has a nitrogen concentration as small as possible, and an argon concentration column formed by rectification in an argon purification column having an argon concentration of 100 theoretical plates or more. A composition that allows separation down to ppm or less is selected and derived, and is supplied to the argon purification column 53.

In this case, by constructing the argon refining column 53 with a packed column having a theoretical plate number of 100 or more, it is possible to separate up to an oxygen concentration of 10 ppm or less, and by setting it to 160 plates or more, the oxygen content in the purified argon. 1 ppm
It can be:

Therefore, the argon refining column 53 is filled with an ordered packing material or an irregular packing material having a theoretical plate number of 100 or more, preferably 160 or more.

Therefore, the argon source gas extracted from the low-pressure column 51b has a composition of oxygen as a main component, argon is 5 to 10%, and nitrogen is 5 ppm or less, preferably 1 ppm.
It is desirable to extract it from the place where it contains a trace amount. Further, by using the low pressure column 51b as a packed column, the above configuration can be more easily selected.

When the argon source gas having such a composition is taken out, the yield of argon is lowered when the amount taken out is the same as that in the conventional method. Therefore, the amount taken out is increased in accordance with the argon concentration in the gas. Must. Therefore, since this becomes the rising gas of the argon refining tower 53, an amount of cold of the condenser 54 that corresponds to this is required. That is, a larger amount of raw material gas is required than the amount of argon raw material gas in a normal crude argon column, and a large amount of reflux liquid is required accordingly.
It is necessary to increase the amount of cold.

A condenser 54 is provided above the argon refining tower 53. The condenser 54 is withdrawn from the lower part of the middle pressure tower (lower tower) 51a of the double rectification tower 51, and the expansion valve 75 lowers the pressure. Oxygen-enriched liquid air is introduced as a cold source from conduit 59. The cold source supplied to the condenser 54 of the argon refining tower 53 is the lower tower 51a of the main rectification tower 51.
In addition to the oxygen-enriched liquefied air derived from the above, liquefied nitrogen or liquefied gas from the attached liquefaction cycle may be used.

The raw material gas thus rising in the argon purifying tower 53 is liquefied in the condenser 54 into a reflux liquid through the pipe 55 and again enters the argon purifying tower 53 through the pipe 56 and descends in the tower 53. Then, liquefaction rectification is performed with the raw material gas rising in the tower 53, and argon gas containing nitrogen of about several% is led out from the top of the tower 53 through a pipe 60, and a control valve 6
The amount is adjusted by 1 and is led out, through a pipe 57 from a stage several stages to a dozen or more stages lower than the top of the column, 99.95% or more of argon,
Purified argon having oxygen of 1 ppm or less, preferably 0.1 ppm or less, and nitrogen content of 100 ppm or less, preferably 50 ppm or less, more preferably 5 ppm or less is discharged as product argon gas or product liquid argon. The argon gas containing a few percent of nitrogen also contains a trace amount of low boiling point components such as hydrogen.

Further, liquefied oxygen is discharged from the bottom of the column, and a pipe 58
To return to the upper tower 51b.

On the other hand, the gas obtained by vaporizing the oxygen-enriched liquid air in the condenser 54 is introduced into a portion of the upper tower having a corresponding gas composition through the pipe 59a. When the liquefied gas as the cold source is liquid nitrogen or the like, it is discharged as a product or circulated as a cycle gas.

FIG. 2 is a graph showing the concentration distribution of each stage of argon, oxygen and nitrogen in the argon refining tower 53. It is clear that the low boiling point gas such as nitrogen is concentrated at the top of the column, and the nitrogen concentration in the liquid is several ppm or less at a number of theoretical plates to a dozen or more stages from the top of the column. This concentration distribution shows the amount of reflux in the argon purification tower,
It varies depending on operating conditions such as the amount of purified argon extracted.

Therefore, an analyzer 71 for detecting the oxygen concentration in the high-purity purified argon is provided in the path 57 for producing the high-purity purified argon, and the high-purity purified argon is obtained by the analysis value detected by the analyzer 71. A means 63 for adjusting the amount of the purified argon discharged and a controller 62 for controlling the same are provided in the path 57 for discharging the purified argon of the purity.

Further, the condenser 5 of the argon refining tower 53
4. Detection / adjustment means 73, 74, 7 for the cold liquefied gas amount, etc.
5 and a controller 62 for controlling the amount of cold liquefied gas in the argon refining tower condenser 54 or the internal pressure of the condenser 54 by these means 73, 74, 75 according to the signal from the oxygen concentration analyzer 71. Set up. The means for controlling the amount of cold is a pressure control valve 74, a flow rate control valve 75, and the like. Control means such as the analyzer 71, the flow rate detector 73, the pressure control valve 74, the flow rate control valves 63 and 75, and the controller 62 for controlling these.
By providing the etc., the argon refining tower 53 can be automatically controlled.

It should be noted that a nitrogen analyzer provided in the path 57 or a signal from an analyzer 71 provided in the path 57 for producing the high-purity purified argon for detecting the oxygen concentration in the high-purity purified argon. Both of the signals from 72
The controller 62 is set so as to control adjusting means such as a valve 61 for adjusting the amount of the argon gas containing nitrogen, which is provided in the path 60 for discharging the low boiling point component mainly composed of nitrogen from the top of the argon refining tower 53. You may.

Next, the high-purity purified argon gas extracted from the top of the above-mentioned argon refining tower 53 from several stages to several tens of stages is subjected to a getter or a purification process by adsorption in the next step as required according to product specifications. Purify.

The number of theoretical plates of the argon refining tower 53 is 10
In the case of the 0th stage, the nitrogen content in the purified argon can be reduced to about 100 to 5 ppm and the oxygen content can be reduced to about several ppm depending on the extraction position from the low pressure column. When both the amounts are about 1.0 ppm, the purified gas produced in the argon purification column 53 is further purified by the adsorption step to reduce the oxygen content and the nitrogen content to 1 ppm or less, or the getter purification step. To remove both oxygen and nitrogen.

When the theoretical plate number of the argon refining tower is 160 plates, the oxygen content can be reduced to about 1.0 ppm or less. Therefore, when the product specifications are about 1.0 ppm for both oxygen content and nitrogen content. The purified gas produced in an argon purification tower of about 160 stages is purified in a getter purification process to reduce the oxygen content and the nitrogen content to 1 ppm or less, or the adsorption process removes nitrogen.

FIG. 3 shows an example of carrying out adsorption purification. The purified liquid argon drawn out from the argon purification tower 53 through the pipe 57 is applied with a necessary pressure to the adsorption device 89 by the pressurizer 80 using the liquid column pressure, then vaporized by the vaporizer 81 and kept at the normal temperature by the heat exchanger 84. After being heated up to, the adsorption tower 89a or 89b
Nitrogen gas and / or oxygen content is reduced to 0.1 ppm or less by adsorption for purification, and the product gas is taken out. When the impurities to be removed are only nitrogen, zeolite is used as the adsorbent. When the impurities to be removed are nitrogen and oxygen, the adsorbent uses molecular sieve carbon as an adsorbent that adsorbs oxygen and zeolite as an adsorbent that adsorbs nitrogen. As the zeolite, MS4A or MS5A is used.
These adsorbents may be packed in separate columns, but may be packed in two layers in one column by a regeneration method. In each case, the adsorption tower is composed of at least two towers that are switched and used.

When the impurities and oxygen and nitrogen cannot be removed by the room temperature adsorption method to the required concentrations or less, the same adsorbent is used to purify by the low temperature adsorption method. When the product is liquid argon, liquid purified argon taken out from the argon purification tower as shown in FIG. 4 may be pressurized by the pressurizer 80 and then introduced into the adsorption device 89 'in a liquid state for adsorption purification. .

The number of theoretical plates of the argon refining tower 53 is 20.
In the case of 0 stage, the oxygen content can be reduced to about 0.1 ppm, so if the product specifications are both oxygen content and nitrogen content of about 0.1 ppm, the product is produced in an argon purification tower of 200 stages or more. The purified argon gas may be purified in a getter refining step to reduce the nitrogen content to 0.1 ppm or less.

FIG. 5 shows the purification process by the getter. The purified liquid argon drawn out from the argon purification tower 53 through the pipe 57 is applied with a pressure device 80 using a liquid column pressure to a pressure required for the getter purification device, then vaporized by a vaporizer 81, and risen by a heat exchanger 84. After heating and further raising the temperature to the reaction temperature with the getter material by the heater devices 85 and 86, it is introduced into the getter cylinder 91 and purified by reducing the nitrogen content to 0.1 ppm or less by the reaction between the getter and mainly nitrogen. ,
Heat is recovered by the heat exchanger 84 and taken out as a product gas.

When the purified gas discharged from the argon purification column 53 through the pipe 57 has a sufficient pressure to pass through the getter cylinder 91, the pipe 6 indicated by an imaginary line does not pass through the pressurizer 80 and the vaporizer 81.
It is supplied to the heat exchanger 84 and the getter cylinder 91 via 7.

The getter cylinder 91 may be a single cylinder, but it is preferable that the getter cylinder 91 is composed of two cylinders which are switched and used depending on the nitrogen concentration in the purified argon to be removed and the period. Further, as will be described later, when removing both oxygen and nitrogen, two getter cylinders filled with two or more different getter materials are connected in series and used. Of course, one cylinder may be filled with two or more kinds of getter materials in layers.

When the oxygen is sufficiently removed in the argon refining tower as described above, the getter is made of 600 alloys of zirconium or zirconium and iron, zirconium and iron and vanadium, zirconium and aluminum and nickel, and zirconium and titanium and nickel. C. to 800.degree. C. are raised to mainly react with nitrogen to remove it.

When purified argon coexists with oxygen, nickel or copper or a composite getter material thereof is used to obtain 300
Remove oxygen at ℃ -400 ℃, then remove zirconium or zirconium alloy and other composite getters
This is removed by reacting with nitrogen in a state where the temperature is raised to 00 ° C or higher.

As described above, according to the present invention, air is introduced into the main rectification column 51 consisting of at least one column to supply several% of argon.
To 10% by number, 10 ppm or less of nitrogen, and an argon source gas consisting of residual oxygen are introduced and introduced into an argon refining column 53 having 100 or more theoretical plates, preferably 160 or more theoretical plates, and rectification is performed. By adjusting the amount of the argon gas contained and discharging it, a purified gas or liquid argon of high purity is produced from several columns to several tens of columns from the top of the column, and liquefied oxygen is derived from the bottom of the column. High-purity product argon can be produced with only one tower.

Further, the purified liquid argon discharged from the argon purification tower 53 is kept as a liquid or after being heated to room temperature, or the gas argon is kept at a low temperature or is heated to raise the adsorption bed 89.
By passing through it, it is possible to further purify and remove a small amount of contained nitrogen and oxygen to produce high-purity argon having impurity nitrogen and oxygen of 1 ppm or less.

Further, the purified liquid argon or the gaseous argon discharged from the argon refining tower 53 is vaporized and heated, or after the temperature is raised, the reaction temperature with the getter is further raised to react with the getter for purification. By removing the traces of nitrogen and oxygen contained therein, ultrapure argon of 0.1 ppm or less can be produced.

Further, an analyzer 71 for detecting the oxygen concentration in the high-purity purified argon is provided in the path 57 for producing the high-purity purified argon, and the purified argon is obtained according to the analysis value detected by the analyzer. By providing the purified argon derivation amount control means 63 and the controller 62 for controlling this, which are provided in the path 57 for derivation of the oxygen, the analyzer 71 for detecting the oxygen concentration in the purified argon derived from the argon refining tower 53. And means 73 and 75 for detecting and adjusting the amount of cold liquefied gas in the argon refining tower condenser 54 and a pressure adjusting means 74, and liquefying the argon refining tower condenser 54 by a signal from the oxygen concentration analyzer 71. A controller 62 for adjusting the amount of cold such as the amount of gas is provided, and the adjusting means 73, 74, 75 are provided.
The argon refining tower 53 can be automatically controlled by controlling the above.

[0044]

As described above, according to the method for producing high-purity argon of the present invention, the purification by the conventional catalyst hydrodeoxidation step and the high-purity argon column can be performed by providing only one argon purification column. The high-purity argon produced by By setting the tower length of the argon refining tower of the present invention and the derivation part of high-purity argon at any optimum position below the top of the tower, the amount of trace oxygen as impurities in the purified argon is reduced to 1 ppm or less, and It is possible to reduce the amount of nitrogen to 5 ppm or less. Further, if necessary, the purified argon is passed through a getter reaction column or an adsorption bed to produce ultrahigh-purity purified argon in which the amount of impurities is 0.1 ppm or less.

Furthermore, an analyzer for detecting the amount of a trace amount of oxygen, which is an impurity in the purified argon, is provided, and the amount of purified argon derived from the argon purification column and the amount of purified argon derived from the argon purification column condenser of the argon purifying column based on the signal from the analyzer. The argon refining tower can be automatically controlled by controlling the amount of cold.

[Brief description of drawings]

FIG. 1 is a system diagram showing an embodiment of the present invention.

FIG. 2 is a diagram showing each concentration distribution of argon, oxygen, and nitrogen in a purified argon column.

FIG. 3 is a system diagram when purified gas argon from a purified argon column is further purified by an adsorber.

FIG. 4 is a system diagram in the case where purified liquid argon from a purified argon column is further purified by an adsorber.

FIG. 5 is a system diagram in the case where purified argon from the purified argon column is further purified by a getter device.

FIG. 6 is a system diagram showing an example of a high-purity argon sampling method by a conventional air cryogenic separation method.

[Explanation of symbols]

51 ... Double rectification column, 51a ... Double (main) rectification column lower column (medium pressure column), 51b ... Main rectification column upper column (low pressure column), 53 ... Argon purification column, 54 ... Condenser, 61 ... Nitrogen-containing argon gas discharge control valve, 62 ... Automatic control controller, 63 ... Purified argon discharge control valve, 71 ... Oxygen concentration analyzer in purified argon, 72 ... Nitrogen concentration analyzer in purified argon, 7
3 ... Flowmeter for cold liquefied gas in condenser 54, 74 ... Pressure control valve for cold liquefied gas in condenser 54, 75 ... Condenser 5
4. Refrigerating liquefied gas flow control valve of 4, 80 ... Pressurizer, 81
... vaporizer, 84 ... heat exchanger, 85, 86 ... heater, 8
9, 89a, 89b ... Adsorber, 91 ... Getter cylinder

Claims (10)

[Claims] 1. Air is compressed, purified and cooled, and is introduced into a main rectification column consisting of at least one column to produce oxygen and / or nitrogen, and an argon source gas is led out from the main rectification column. The rectification is carried out by introducing into an argon purification column having 100 or more theoretical plates, preferably 160 or more theoretical plates, and argon containing nitrogen is discharged from the top of the tower by adjusting the amount thereof and from several to ten or more trays from the top of the tower. A method for producing high-purity argon, which comprises producing highly pure purified argon from below and discharging liquefied oxygen from the bottom of the column. 2. The argon raw material gas discharged from the main rectification column has a nitrogen content of 50 ppm or less, preferably 5 pp.
The method for producing high-purity argon according to claim 1, characterized in that it is m or less. 3. The method for producing high-purity argon according to claim 1, wherein the argon refining tower is a packed tower packed with an ordered packing material or an irregular packing material. 4. The cold source supplied to the condenser of the argon purification column is oxygen-enriched liquefied air or liquefied nitrogen derived from the lower column of the main rectification column, or liquefied gas from an attached liquefaction cycle. The method for producing high-purity argon according to claim 1. 5. The purified liquid argon or gas argon, which is discharged from the argon purification tower, is vaporized and heated, or further heated to a reaction temperature with a getter and purified by reacting with a getter. The method for producing high-purity argon according to claim 1, characterized in that a trace amount of nitrogen and oxygen are removed. 6. The purified liquid argon, which is discharged from the argon purification column, is further purified by passing it through the adsorption bed as a liquid or after vaporization to remove a trace amount of nitrogen and oxygen contained therein. The method for producing high-purity argon according to claim 1. 7. The purified gas argon or the vaporized argon discharged from the argon purification tower is kept at a low temperature or after the temperature is raised to room temperature, and further purified by passing through an adsorption bed to remove a trace amount of nitrogen and oxygen contained therein. The method for producing high-purity argon according to claim 1, wherein 8. A main rectification column comprising at least one column for producing oxygen and / or nitrogen by introducing compressed, purified and cooled raw material air, and a route for deriving an argon raw material gas from the main rectification column, An argon refining tower which is a packed tower having 100 or more theoretical plates for introducing rectification by introducing an argon raw material gas,
A route for deriving argon containing nitrogen from the top of the argon purifying column, a means for adjusting the amount of the nitrogen-containing argon deriving, and a purified argon having a higher theoretical purity than the theoretical top of the column from several to ten or more stages. An apparatus for producing high-purity argon, characterized in that it has a path for producing liquefied oxygen and a path for discharging liquefied oxygen from the bottom of the column. 9. An analyzer for detecting the oxygen concentration in the purified argon and a means for detecting and adjusting the derivation flow rate of the purified argon are provided in the purified argon derivation path of the argon refining tower, and the oxygen concentration analyzer 9. The apparatus for producing high-purity argon according to claim 8, further comprising a controller for controlling the purified argon derivation flow rate adjusting means according to the signal of FIG. 10. An analyzer for detecting the oxygen concentration in the purified argon derived from the argon purification tower, and means for detecting and adjusting the flow rate and / or pressure of the liquefied gas for cooling of the condenser of the argon purification tower are provided. 9. The apparatus for producing high-purity argon according to claim 8, further comprising a controller for controlling a refrigerating amount such as a refrigerating liquefied gas amount in the refining tower condenser in response to a signal from the oxygen concentration analyzer.