Apparatus for producing high-purity liquefied argon and method for producing high-purity liquefied argon

Abstract

To provide an apparatus and a method for producing high-purity liquefied argon in which oxygen is removed and the content of low-boiling-point components with a boiling point lower than that of argon is also reduced.SOLUTION: An apparatus for producing high-purity liquefied argon includes: a container for temporarily storing raw material liquefied argon; a condenser connected to the container; a heat exchanger for raising a temperature of argon gas vaporized by the condenser to a room temperature; an argon gas compressor for compressing the argon gas that has passed through the heat exchanger; an adsorption column containing a getter agent that reacts with oxygen contained in the compressed argon gas obtained by compression with the argon gas compressor; a supply path for supplying the purified argon gas, which is obtained by purification in the adsorption column, to the heat exchanger; and a supply path for supplying the purified argon gas, which has been passed through the heat exchanger, to the condenser. A liquefied argon recovery path for discharging and recovering the liquefied argon obtained by liquefying the purified argon gas in the condenser to the outside of the system, and a low-boiling-point component discharge path for discharging low-boiling-point components from the inside of the condenser to the outside of the system are connected to the condenser.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an apparatus for producing high-purity liquefied argon and a method for producing high-purity liquefied argon. [Background technology]

[0002] Argon is a gas that makes up approximately 0.93% of the air. Because it undergoes almost no chemical reactions, it is used as an inert gas in steelmaking, welding, silicon production, etc. Argon can be recovered, for example, in cryogenic air separation units. The purity of the recovered argon is usually around 99.9%, and it contains impurities such as oxygen and nitrogen.

[0003] A known method for removing oxygen and nitrogen from argon is to react it with a getter agent. Patent Document 1 describes a method for producing high-purity argon by compressing, purifying, and cooling air and introducing it into a main rectification column consisting of at least one column to produce oxygen and / or nitrogen. The argon raw material gas is then extracted from the main rectification column and introduced into an argon purification column with 100 or more theoretical plates for rectification. Nitrogen-containing argon is extracted from the top of the column at a controlled amount. High-purity purified argon is produced from several to several dozen columns below the top. Liquid oxygen is extracted from the bottom of the column. Patent Document 1 also describes a method for further purifying argon by vaporizing or heating the purified liquid argon or gaseous argon extracted from the argon purification column, and then further heating it to a reaction temperature with a getter to react with the getter to purify the argon and remove traces of nitrogen and oxygen. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 7-133982 Summary of the Invention [Problem to be solved by the invention]

[0005] As disclosed in the above-mentioned Patent Document 1, oxygen and nitrogen contained in argon can be removed by reacting them with a getter agent. The getter agent is usually regenerated and reused. A mixed gas of hydrogen and nitrogen, or a mixed gas containing argon, is used to regenerate the getter agent. As a result, the product argon may be contaminated with components with boiling points lower than that of argon (hereinafter referred to as low-boiling-point components), such as hydrogen and nitrogen, which can cause quality defects in the product argon.

[0006] The present invention has been made in light of the above-mentioned circumstances, and its object is to provide an apparatus capable of producing high-purity liquefied argon from which oxygen has been removed and from which the content of low-boiling point components having boiling points lower than that of argon has been reduced, and a method for producing such high-purity liquefied argon. [Means for solving the problem]

[0007] The present invention is as follows. [1] An apparatus for producing high-purity liquefied argon, comprising: a container for temporarily storing raw liquefied argon; a condenser connected to the container; a heat exchanger for heating the argon gas vaporized in the condenser to room temperature; an argon gas compressor for compressing the argon gas that has passed through the heat exchanger; an adsorption tower provided with a getter agent that reacts with oxygen contained in the compressed argon gas compressed in the argon gas compressor; a supply path for supplying purified argon gas obtained by purification in the adsorption tower to the heat exchanger; and a supply path for supplying the purified argon gas that has passed through the heat exchanger to the condenser, wherein the condenser is connected to a liquefied argon recovery path for discharging and recovering the liquefied argon obtained by liquefying the purified argon gas in the condenser outside the system, and a low-boiling-point component discharge path for discharging low-boiling-point components from the condenser outside the system. [2] The manufacturing apparatus described in [1], wherein the connection position between the low-boiling point component discharge path and the condenser is above the liquid level of the liquefied argon in the condenser, and / or is at the same position as the connection position between the condenser and the liquefied argon recovery path. [3] The manufacturing apparatus according to [1] or [2], wherein the low-boiling point component discharge path passes through the heat exchanger and then extends to the outside of the system. [4] A manufacturing apparatus according to any one of [1] to [3], wherein a supply path for supplying the raw liquefied argon to the container is connected to the container, the supply path branches, and the branch path is connected to a path connecting the heat exchanger and the argon gas compressor, and the branch path is provided with a vaporizer for vaporizing the raw liquefied argon and an argon gas compressor suction pressure adjustment valve. [5] A method for producing high-purity liquefied argon using a high-purity liquefied argon production apparatus having a container for temporarily storing raw liquefied argon, a condenser connected to the container, a heat exchanger for heating the argon gas vaporized in the condenser to room temperature, an argon gas compressor for compressing the argon gas that has passed through the heat exchanger, an adsorption tower provided with a getter agent that reacts with oxygen contained in the compressed argon gas compressed in the argon gas compressor, a supply path for supplying the purified argon gas purified in the adsorption tower to the heat exchanger, and a supply path for supplying the purified argon gas that has passed through the heat exchanger to the condenser, wherein the purified argon gas that has passed through the heat exchanger is condensed and liquefied in the condenser, and the resulting liquefied argon is discharged outside the system and recovered, and low-boiling-point components in the condenser are discharged outside the system. [6] The manufacturing method according to [5], wherein the low boiling point components are discharged from the system from a position above the liquid level of the liquefied argon in the condenser, and / or discharged together with the liquefied argon obtained by condensation and liquefaction in the condenser, and the low boiling point components and the liquefied argon are separated. [7] The production method according to [5] or [6], wherein the low boiling point components in the condenser are passed through the heat exchanger before being discharged to the outside of the system. [8] The manufacturing method according to any one of [5] to [7], wherein the raw argon gas obtained by vaporizing a portion of the raw liquefied argon before being supplied to the container is mixed with the argon gas that has passed through the heat exchanger. [Effects of the Invention]

[0008] According to the present invention, a condenser that condenses and liquefies purified argon gas obtained by purification in an adsorption tower equipped with a getter agent is provided with a low-boiling-point component discharge path for discharging low-boiling-point components in the condenser to the outside of the system, thereby providing an apparatus and method for producing high-purity liquefied argon from which oxygen has been removed and which is minimally contaminated with low-boiling-point components. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram showing a first embodiment of an air separation unit according to the present invention. [Figure 2] FIG. 2 is a schematic diagram showing a second embodiment of an air separation unit according to the present invention. [Figure 3] FIG. 3 is a schematic diagram showing a third embodiment of an air separation unit according to the present invention. [Figure 4] FIG. 4 is a schematic diagram showing a fourth embodiment of an air separation unit according to the present invention. [Figure 5] FIG. 5 is a schematic diagram showing a configuration in which the condenser 11a is disposed outside the container 11. In FIG. DETAILED DESCRIPTION OF THE INVENTION

[0010] The following describes in detail the apparatus for producing high-purity liquefied argon and the method for producing high-purity liquefied argon according to the present invention based on the following embodiments. However, the present invention is not limited to the following embodiments, and modifications can be made within the scope of the above and below-described spirit, and all such modifications are within the technical scope of the present invention. In the drawings, when symbols and the like are omitted for convenience, reference is made to the specification or other drawings. Furthermore, various dimensions in the drawings may differ from actual dimensions.

[0011] (Embodiment 1) An apparatus for producing high-purity liquefied argon according to a first embodiment of the present invention includes a container for temporarily storing raw liquefied argon, a condenser connected to the container, a heat exchanger for heating the argon gas vaporized in the condenser to room temperature, an argon gas compressor for compressing the argon gas that has passed through the heat exchanger, an adsorption tower provided with a getter agent that reacts with oxygen contained in the compressed argon gas compressed by the argon gas compressor, a supply path for supplying the purified argon gas purified in the adsorption tower to the heat exchanger, and a supply path for supplying the purified argon gas that has passed through the heat exchanger to the condenser. The condenser is further characterized by the presence of a liquefied argon recovery path for discharging and recovering the liquefied argon obtained by liquefying the purified argon gas in the condenser, and a low-boiling-point component discharge path for discharging low-boiling-point components from the condenser to the system. By providing the condenser with a low boiling point component discharge path for discharging low boiling point components from the condenser to the outside of the system, the amount of low boiling point components mixed into the liquefied argon can be reduced, thereby increasing the purity of the liquefied argon.

[0012] A first embodiment of an apparatus for producing high-purity liquefied argon according to the present invention will be described below with reference to Fig. 1. The apparatus shown in Fig. 1 includes an insulated box 10, a container 11, a condenser 11a, a heat exchanger 12, an argon gas compressor 13, an adsorption tower 14, a valve 15, a raw liquefied argon vaporizer 17, and an argon gas compressor suction pressure regulating valve 18.

[0013] A supply line L1 for supplying liquefied argon used as a raw material is connected to vessel 11. The raw liquefied argon supplied from supply line L1 may be, for example, liquefied argon recovered when oxygen or nitrogen is produced from air in an air separation unit. The raw liquefied argon supplied from supply line L1 to vessel 11 is temporarily stored in vessel 11.

[0014] A condenser 11a is connected to the vessel 11, and in Fig. 1, the condenser 11a is disposed inside the vessel 11. The raw liquefied argon supplied to the vessel 11 exchanges heat with purified argon gas supplied from a supply line L6, and the vaporized argon gas is supplied to the heat exchanger 12 through a line L2.

[0015] The argon gas supplied to the heat exchanger 12 through the path L2 exchanges heat with the purified argon gas supplied to the heat exchanger 12 through the supply line L5, and is heated to room temperature (for example, 5 to 35°C). The argon gas heated to room temperature in the heat exchanger 12 is supplied to the argon gas compressor 13 through the path L3. In the argon gas compressor 13, the argon gas is compressed to, for example, about 0.05 to 1.00 MPaG.

[0016] The compressed argon gas obtained by compression in the argon gas compressor 13 is supplied to the adsorption tower 14 via a path L4.

[0017] The adsorption tower 14 is equipped with a getter agent that reacts with and adsorbs oxygen, and the compressed argon gas supplied to the adsorption tower 14 is purified by removing oxygen by passing through the adsorption tower 14. As the getter agent, commercially available known materials such as copper, copper alloy, titanium, titanium alloy, zirconium, and zirconium alloy can be used.

[0018] The purified argon gas obtained by purification in the adsorption tower 14 is returned to the heat exchanger 12 through the supply line L5. As described above, the purified argon gas supplied to the heat exchanger 12 from the supply line L5 is cooled by heat exchange with the argon gas supplied to the heat exchanger 12 from the line L2.

[0019] The purified argon gas cooled in the heat exchanger 12 is supplied to the condenser 11a through the supply line L6. As described above, the purified argon gas supplied to the condenser 11a is condensed and liquefied by heat exchange with the raw liquefied argon gas supplied from the supply line L1.

[0020] The liquefied argon obtained by condensation and liquefaction in the condenser 11a is discharged outside the system through the liquefied argon recovery line L7 connected to the condenser 11a and recovered as high-purity liquefied argon product. The condenser 11a is also connected to a low-boiling-point component discharge line L11, which discharges low-boiling-point components from the condenser 11a outside the system. By discharging the low-boiling-point components from the condenser 11a through the low-boiling-point component discharge line L11, the amount of low-boiling-point components contained in the liquefied argon recovered through the liquefied argon recovery line L7 can be reduced, thereby increasing the purity of the argon. Specifically, when oxygen is removed from compressed argon gas in an adsorption tower 14 equipped with a getter agent to increase the argon purity, hydrogen and nitrogen are used to regenerate the getter agent, but hydrogen and nitrogen can sometimes be mixed into the compressed argon gas. On the other hand, the high-purity liquefied argon production system according to the present invention discharges low-boiling-point components such as hydrogen and nitrogen from the condenser 11a outside the system, thereby increasing the purity of the argon. Low-boiling-point components are substances that have a boiling point lower than the boiling point of argon (-185.8°C), and examples include hydrogen (boiling point -259.2°C) and nitrogen (boiling point -195.79°C).

[0021] A valve 15 may be provided in the low boiling point component discharge path L11, which allows the amount of low boiling point components discharged outside the system to be adjusted.

[0022] 1, the low boiling point component discharge line L11 can be connected to a position above the liquid level of the liquefied argon in the condenser 11a, thereby allowing low boiling point components that are not condensed and remain in a gaseous state (e.g., hydrogen) to be discharged to the outside of the system. The low boiling point component discharge line L11 is preferably connected to a position opposite the connection between the condenser 11a and the supply line L6, which supplies purified argon gas cooled in the heat exchanger 12 to the condenser 11a.

[0023] The supply line L1, which supplies the raw liquefied argon to the container 11, may branch along the way. A branch line L1a of the supply line L1 may be connected to a path L3 connecting the heat exchanger 12 and the argon gas compressor 13, for example. A vaporizer 17 for vaporizing the raw liquefied argon may be provided in the branch line L1a. For example, upon startup of the apparatus, argon gas vaporized by the vaporizer 17 may be supplied to the system through the branch line L1a, thereby quickly replacing the gas present in the system with argon gas. An argon gas compressor suction pressure regulating valve 18 may be provided in the branch line L1a. By supplying argon gas to the argon gas compressor 13 through the branch line L1a, the suction pressure of the argon gas compressor 13 can be stabilized, thereby stabilizing the pressure in the system.

[0024] A valve 19 may be provided on the supply line L1 for supplying the raw liquefied argon to the vessel 11. This allows the amount of raw liquefied argon supplied to the vessel 11 to be adjusted.

[0025] (Embodiment 2) Next, a second embodiment of the apparatus for producing high-purity liquefied argon according to the present invention will be described with reference to Figure 2. In Figure 2, the same components as those in other figures are designated by the same reference numerals to avoid redundant description. In Figure 2, in contrast to the first embodiment shown in Figure 1, the low-boiling-point component discharge line L11 connected to the condenser 11a is connected to the heat exchanger 12, passes through the heat exchanger 12, and then extends outside the system. This reduces the loss of refrigeration within the insulated box 10.

[0026] (Embodiment 3) Next, a third embodiment of the apparatus for producing high-purity liquefied argon according to the present invention will be described with reference to Figure 3. In Figure 3, the same components as those in other figures are designated by the same reference numerals to avoid redundant description. In Figure 3, unlike the first embodiment shown in Figure 1, the connection position between the low-boiling-point component discharge line L11 and the condenser 11a is the same as the connection position between the condenser 11a and the liquefied argon recovery line L7. By connecting the low-boiling-point component discharge line L11 immediately above the connection position between the condenser 11a and the liquefied argon recovery line L7, low-boiling-point components that have condensed into a liquid state (for example, trace amounts of nitrogen) can be discharged outside the system.

[0027] (Fourth embodiment) Next, a fourth embodiment of the apparatus for producing high-purity liquefied argon according to the present invention will be described with reference to Figure 4. In Figure 4, the same components as those in other figures are designated by the same reference numerals to avoid redundant description. In Figure 4, in contrast to the third embodiment shown in Figure 3, the low-boiling-point component discharge line L11 connected to the condenser 11a is connected to the heat exchanger 12, passes through the heat exchanger 12, and then extends outside the system. This reduces the loss of refrigeration within the insulated box 10.

[0028] The low-boiling-point component discharge line L11 may be connected to a position above the liquid level of the liquefied argon in the condenser 11a as shown in Figures 1 and 2, or may be connected to the same position as the condenser 11a and the liquefied argon recovery line L7 as shown in Figures 3 and 4. However, the low-boiling-point component discharge line L11 may be provided both at a position above the liquid level of the liquefied argon in the condenser 11a and at the same position as the condenser 11a and the liquefied argon recovery line L7. This allows both low-boiling-point components that are not condensed and are in a gaseous state (e.g., hydrogen) and those that are condensed and are in a liquid state (e.g., trace amounts of nitrogen) to be discharged outside the system, thereby further increasing the purity of the liquefied argon.

[0029] 1 to 4 show a configuration in which the condenser 11a is disposed inside the vessel 11, but the present invention is not limited to this configuration, and the condenser 11a may be disposed outside the vessel 11. For example, as shown in FIG. 5, the condenser 11a is disposed outside the vessel 11, the bottom of the vessel 11 and the bottom of the condenser 11a are connected by a path L12, and the top of the condenser 11a and the top of the vessel 11 are connected by a path L13. The raw liquefied argon supplied to the vessel 11 from the supply path L1 is supplied to the condenser 11a through the path L12. The raw liquefied argon supplied to the condenser 11a exchanges heat with purified argon gas supplied from the heat exchanger 12 through the path L6, and the vaporized argon gas is supplied to the vessel 11 through the path L13. Meanwhile, purified argon gas supplied to the condenser 11a from the line L6 is condensed and liquefied by heat exchange with the raw liquefied argon. The resulting liquefied argon is discharged to the outside of the system through a liquefied argon recovery line L7 connected to the condenser 11a and recovered as high-purity liquefied argon product. A low-boiling component discharge line L11 may be further connected to the condenser 11a. By discharging low-boiling components from the condenser 11a to the outside of the system, the purity of the liquefied argon can be further increased. A valve 15 may be provided midway along the low-boiling component discharge line L11. This allows the amount of low-boiling components discharged to the outside of the system to be adjusted.

[0030] 1 to 4 do not show the details of the adsorption tower 14, but the number of adsorption towers in the adsorption tower 14 is not limited to one, and two or more towers may be provided. Providing multiple towers allows switching, making continuous operation possible. While FIGS. 1 to 4 show a configuration in which the container 11 and the heat exchanger 12 are housed in a cool box 10, the present invention is not limited to this. For example, the container 11 and the heat exchanger 12 may be simply insulated using a heat insulating material to reduce refrigeration loss.

[0031] The apparatus for producing high-purity liquefied argon according to the present invention can produce liquefied argon containing 0.1 ppm or less of low-boiling components. This high-purity liquefied argon can be used as a raw material for industrial gases, for example, in steelworks.

[0032] The high-purity liquefied argon production apparatus according to the present invention can be easily retrofitted to existing liquefied argon production equipment. That is, by using liquefied argon produced in an existing liquefied argon production apparatus as a raw material and subjecting it to the above-described production method, high-purity liquefied argon with a low content of low-boiling point components can be produced.

[0033] Furthermore, the Sustainable Development Goals (SDGs) call for the continuous improvement of resource use efficiency, and the present invention can contribute to part of these activities.

[0034] The present invention will be described in more detail below with reference to examples. However, the present invention is not limited to the following examples, and it is of course possible to carry out the invention by making modifications within the scope that is compatible with the above-mentioned and below-mentioned aims, and all such modifications are included in the technical scope of the present invention. [Example]

[0035] The effect of discharging low boiling point components was verified using the liquefied argon production system shown in Figure 1. The flow rate of purified argon gas at the outlet of the adsorption tower 14 was set to 1000 Nm 3 / h, and the pressure of the purified argon gas was 0.15 MPaG. The hydrogen concentration in the purified argon gas at the outlet of the adsorption tower 14 was 1000 ppm or 100 ppm. The low boiling point components in the condenser 11a were discharged from the low boiling point component discharge path L11 at a rate of 10 Nm 3 / h or 20Nm 3 The hydrogen concentration in the liquefied argon recovered from the liquefied argon recovery line L7 was measured and is shown in Table 1 below.

[0036] [Table 1]

[0037] From Table 1, the following can be considered. As shown in Nos. 1 and 3, low boiling point components were discharged from the low boiling point component discharge path L11 at 10 Nm 3 / h, that is, 1% of the purified argon gas flow rate, the hydrogen removal rate was about 76 to 77%. 3 / h, i.e., 2% of the purified argon gas flow rate, the hydrogen removal rate was about 86 to 87%. It can be seen that by discharging the low boiling point components in the condenser 11a to the outside of the system through the low boiling point component discharge path L11, the amount of low boiling point components (typically, the amount of hydrogen) contained in the liquefied argon recovered as a product can be reduced. [Explanation of symbols]

[0038] 10 Cooler Box 11 Container 11a Condenser 12 Heat exchanger 13 Argon gas compressor 14 Adsorption tower 15 valves 17. Raw material liquefied argon vaporizer 18 Argon gas compressor suction pressure regulating valve 19 valves L1 supply path L2~L4 route L5, L6 supply path L7 Liquid argon recovery line L11 Low boiling point component discharge path L12 and L13 pathways

Claims

1. a container for temporarily storing the raw material liquefied argon; a condenser connected to the vessel; a heat exchanger that heats the argon gas vaporized in the condenser to room temperature; an argon gas compressor for compressing the argon gas that has passed through the heat exchanger; an adsorption tower provided with a getter agent that reacts with oxygen contained in the compressed argon gas obtained by compression in the argon gas compressor; a supply line for supplying purified argon gas obtained by purification in the adsorption tower to the heat exchanger; a supply line for supplying the purified argon gas that has passed through the heat exchanger to the condenser, The condenser includes: a liquefied argon recovery line for discharging the liquefied argon obtained by liquefying the purified argon gas in the condenser to the outside of the system and recovering it; a low-boiling-point component discharge path for discharging low-boiling-point components having boiling points lower than that of argon from the condenser to the outside of the system; 1. A high-purity liquefied argon production apparatus, comprising:

2. The connection position of the low boiling point component discharge path and the condenser is and / or 2. The manufacturing apparatus according to claim 1, wherein the condenser and the liquefied argon recovery line are connected at the same position.

3. 3. The manufacturing apparatus according to claim 1, wherein the low-boiling-point component discharge path passes through the heat exchanger and then extends to the outside of the system.

4. a supply path for supplying the raw material liquefied argon to the container is connected to the container; The supply path is branched, a branch passage connected to a passage connecting the heat exchanger and the argon gas compressor; 4. The manufacturing apparatus according to claim 1, wherein the branch line is provided with a vaporizer for vaporizing the raw material liquefied argon and an argon gas compressor intake pressure regulating valve.

5. a container for temporarily storing the raw material liquefied argon; a condenser connected to the vessel; a heat exchanger that heats the argon gas vaporized in the condenser to room temperature; an argon gas compressor for compressing the argon gas that has passed through the heat exchanger; an adsorption tower provided with a getter agent that reacts with oxygen contained in the compressed argon gas obtained by compression in the argon gas compressor; a supply line for supplying purified argon gas obtained by purification in the adsorption tower to the heat exchanger; a supply line for supplying the purified argon gas that has passed through the heat exchanger to the condenser, The purified argon gas that has passed through the heat exchanger is condensed and liquefied in the condenser, and the resulting liquefied argon is discharged outside the system and recovered; and A method for producing high-purity liquefied argon, characterized in that low-boiling point components having boiling points lower than that of argon are discharged from the condenser to the outside of the system.

6. The low boiling point component is Discharge the liquefied argon from the condenser at a position above the liquid level of the liquefied argon, and / or 6. The method according to claim 5, wherein the low-boiling point components are discharged from the system together with the liquefied argon obtained by condensation and liquefaction in the condenser, and the liquefied argon is separated from the low-boiling point components.

7. 7. The production method according to claim 5, wherein the low boiling point components in the condenser are passed through the heat exchanger before being discharged to the outside of the system.

8. a raw argon gas obtained by vaporizing a portion of the raw liquefied argon before being supplied to the container; 8. The method according to claim 5, wherein the argon gas is mixed with the argon gas that has passed through the heat exchanger.

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