A method for preparing high-purity argon from air using a three-stage method

Abstract

The present invention provides a method for producing high-purity argon from air using a three-stage process. Using air as the raw material, a first-stage pressure swing adsorption unit, a second-stage pressure swing adsorption unit, and a third-stage catalytic deoxygenation unit are operated in series. The first-stage pressure swing adsorption unit includes a first-stage adsorption tower for removing oxygen, carbon dioxide, and water to produce an intermediate gas rich in nitrogen and argon. The second-stage pressure swing adsorption unit includes a second-stage adsorption tower for further removing nitrogen to produce an argon-rich gas that also contains trace amounts of oxygen. The third-stage catalytic deoxygenation unit includes an oxygen removal system and a carbon dioxide removal system. The oxygen removal system uses carbon combustion to remove trace oxygen from the argon-rich gas to produce carbon dioxide. The carbon dioxide removal system further removes carbon dioxide to produce high-purity argon. The present invention utilizes a non-cryogenic process, enabling the production of argon at any time, making argon acquisition more convenient and efficient.

Description

Technical Field

[0001] The invention belongs to the technical field of gas separation, and in particular relates to a method for preparing high-purity argon from air by adopting a three-stage method. Background Art

[0002] Currently, there are two common methods for obtaining argon. One uses air as the raw material. Because argon's boiling point is between that of oxygen and nitrogen, it can be separated using an air separation unit. This process involves distilling the air, liquefying the oxygen using a condenser, removing the liquid oxygen, and then cooling the liquefied argon, which has a lower boiling point. This method relies on the presence of cryogenic equipment and uses direct cryogenic separation to produce high-purity argon. However, this process requires refrigeration capacity to accumulate, which takes a long time to start up, places high demands on pipeline sealing and the specifications of measuring instruments, and is generally only suitable for large-scale gas use sites. The second method is to recover and purify the crude argon emitted from argon use sites, directly processing the argon-rich gas to produce the argon product. However, argon-rich gas is also generally obtained through cryogenic distillation, which is relatively expensive. Therefore, these processes rely on large-scale equipment and equipment and are not suitable for mobile operations or applications requiring immediate argon production.

[0003] Therefore, it is necessary to provide an improved technical solution to the above-mentioned deficiencies in the prior art. Summary of the Invention

[0004] In view of the problem that the existing technology relies on deep-cold equipment and cannot prepare argon at any time, the purpose of the present invention is to provide a method for preparing high-purity argon from air using a three-stage method. Using air as raw material and a non-low-temperature method, argon can be prepared at any time, making the acquisition of argon more convenient and more efficient.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] The present invention provides a method for preparing high-purity argon from air using a three-stage process. The method uses air as a raw material and adopts a first-stage pressure swing adsorption device, a second-stage pressure swing adsorption device and a third-stage catalytic deoxidation device operated in series to prepare high-purity argon.

[0007] The first-stage pressure swing adsorption device includes a first-stage adsorption tower, and the second-stage pressure swing adsorption device includes a second-stage adsorption tower; the first-stage adsorption tower is used to remove oxygen, carbon dioxide and water to obtain an intermediate gas rich in nitrogen and argon; the second-stage adsorption tower is used to further remove nitrogen from the intermediate gas rich in nitrogen and argon flowing out of the first-stage adsorption tower to obtain an argon-rich gas, which also contains trace amounts of oxygen;

[0008] The third stage catalytic deoxidation device includes an oxygen removal system and a carbon dioxide removal system. The oxygen removal system uses carbon combustion to remove trace oxygen from the argon-rich gas to generate carbon dioxide; the carbon dioxide removal system further removes carbon dioxide generated from the oxygen removal system to obtain high-purity argon.

[0009] Each adsorption tower of the first section adsorption tower undergoes the steps of adsorption, upper equal pressure drop, upper and lower equal pressure drop simultaneously, inversion, purging, upper equal pressure increase, upper and lower equal pressure increase simultaneously, and final increase in one cycle. Each adsorption tower of the second section adsorption tower undergoes the steps of adsorption, upper equal pressure drop, inversion, purging, upper equal pressure increase, and final increase in one cycle.

[0010] Preferably, the first-section adsorption tower includes two adsorption towers connected in parallel, and the second-section adsorption tower includes two or more adsorption towers connected in parallel; the number of pressure equalization steps in the upper pressure drop step of the second-section adsorption tower is 1 to 5 times, and the number of pressure equalization steps in the upper pressure increase step of the second-section adsorption tower is 1 to 5 times.

[0011] Preferably, the second-stage adsorption tower comprises 2-4 adsorption towers connected in parallel; the pressure equalization times of the pressure drop step at the upper part of the second-stage adsorption tower is 1, and the pressure equalization times of the pressure increase step at the upper part of the second-stage adsorption tower is 1 to 2.

[0012] Preferably, the total volume content of nitrogen and argon in the intermediate gas rich in nitrogen and argon is 95-99.5%; the volume content of argon in the argon-rich gas is 99-99.9%; and the volume content of argon in the high-purity argon gas is 99.99-99.999%.

[0013] Preferably, if the oxygen content of the argon-rich gas after passing through the oxygen removal system is 100 ppm, the volume content of argon in the high-purity argon gas is 99.99%; if the oxygen content of the argon-rich gas after passing through the oxygen removal system is 50 ppm, the volume content of argon in the high-purity argon gas is 99.995%; if the oxygen content of the argon-rich gas after passing through the oxygen removal system is 10 ppm, the volume content of argon in the high-purity argon gas is 99.999%.

[0014] Preferably, the adsorption pressure of the adsorption tower during the adsorption step of the first adsorption tower is 0.6-1.0 MPa; the adsorption pressure of the adsorption tower during the adsorption step of the second adsorption tower is 0.04-1.0 MPa; the inlet pressure of the third catalytic deoxidation device is 0.1-1.0 MPa;

[0015] Preferably, the adsorption pressure of the adsorption tower after the upper pressure drop step of the first adsorption tower is 0.3 to 0.5 MPa; the adsorption pressure of the adsorption tower after the upper pressure drop step of the second adsorption tower is 0.02 to 0.5 MPa.

[0016] Preferably, the oxygen removal system and the carbon dioxide removal system are operated in series; the oxygen removal system includes a third-stage deoxygenation tower, and the third-stage deoxygenation tower includes 3 or more deoxygenation towers connected in series; the carbon dioxide removal system includes a third-stage adsorption tower, which adopts a pressure swing adsorption or temperature swing adsorption method, and the third-stage adsorption tower includes 2 adsorption towers connected in parallel;

[0017] Preferably, the adsorbent filled in the first-stage adsorption tower is 4A molecular sieve or carbon molecular sieve; the adsorbent filled in the second-stage adsorption tower is LiX, NaX or CaX zeolite molecular sieve; the adsorbent filled in the third-stage deoxygenation tower is a transition metal-loaded carbon material, and oxygen reacts with the transition metal-loaded carbon material to generate carbon dioxide.

[0018] Preferably, the specific method of achieving the upper and lower pressure drops of the first-stage adsorption tower is as follows: the adsorption tower that has completed the adsorption step is pressurized to the adsorption tower that needs to perform the pressure increase step, so that the pressure of the adsorption tower in the pressure drop step is reduced, and the pressure of the adsorption tower in the pressure increase step is increased, until the pressures of the two adsorption towers are consistent; wherein, the upper valve of the adsorption tower is first opened to perform the upper pressure drop, so that the adsorption pressure of the adsorption tower that has completed the adsorption step is reduced to a gauge pressure of 0.3 to 0.5 MPa; then, the lower valve of the adsorption tower is opened to simultaneously perform the upper and lower pressure drops, so that the pressures of the two adsorption towers are consistent;

[0019] Preferably, the specific method for increasing the upper pressure of the first-stage adsorption tower and increasing the upper and lower pressures at the same time is as follows: the adsorption tower after the purge step is completed is connected to the adsorption tower in the equal pressure drop step to achieve pressure increase until the pressures of the two adsorption towers are consistent; wherein, the upper valve of the adsorption tower is first opened to increase the upper pressure, so that the adsorption pressure of the adsorption tower after the purge step is increased by 0.1-0.15MPa; then the lower valve of the adsorption tower is opened to simultaneously increase the upper pressure and the lower pressure, so that the pressures of the two adsorption towers are consistent.

[0020] Preferably, if the first-stage adsorption tower is used to remove nitrogen, carbon dioxide, and water first, the type of adsorbent in the first-stage adsorption tower and the second-stage adsorption tower needs to be replaced, and the steps, number of adsorption towers, and adsorption pressure of each adsorption tower in one cycle need to be converted to each other, while the third-stage catalytic deoxygenation device and method remain unchanged;

[0021] At this time, the first-stage adsorption tower produces an intermediate gas rich in oxygen and argon, with a total volume content of oxygen and argon of 80-90%. The second-stage adsorption tower produces an argon-rich gas with a volume content of 99-99.9%. The third-stage catalytic deoxidation device produces high-purity argon with a volume content of 99.99-99.999%.

[0022] The adsorbent filled in the first adsorption tower is LiX, NaX or CaX zeolite molecular sieve; the adsorbent filled in the second adsorption tower is 4A molecular sieve or carbon molecular sieve;

[0023] Each adsorption tower of the first stage adsorption tower undergoes the steps of adsorption, upper pressure drop, inversion, purging, upper pressure increase, and final increase in sequence within one cycle. Each adsorption tower of the second stage adsorption tower undergoes the steps of adsorption, upper pressure drop, upper and lower pressure drop simultaneously, inversion, purging, upper pressure increase, upper and lower pressure increase simultaneously, and final increase in one cycle.

[0024] The first adsorption tower includes two or more adsorption towers connected in parallel; the second adsorption tower includes two adsorption towers connected in parallel; the pressure equalization times of the pressure drop step at the top of the first adsorption tower is 1 to 5 times, and the pressure equalization times of the pressure increase step at the top of the first adsorption tower is 1 to 5 times;

[0025] The adsorption pressure of the adsorption tower during the adsorption step of the first adsorption tower is 0.04 to 1.0 MPa gauge pressure; the adsorption pressure of the adsorption tower during the adsorption step of the second adsorption tower is 0.6 to 1.0 MPa gauge pressure; the adsorption pressure of the adsorption tower after the upper pressure drop step of the first adsorption tower is 0.02 to 0.5 MPa gauge pressure; the adsorption pressure of the adsorption tower after the upper pressure drop step of the second adsorption tower is 0.3 to 0.5 MPa gauge pressure.

[0026] Preferably, the first adsorption tower comprises 2-4 adsorption towers connected in parallel; the pressure equalization times of the pressure drop step at the top of the first adsorption tower is 1, and the pressure equalization times of the pressure increase step at the top of the second adsorption tower is 1 to 2.

[0027] Preferably, when the first-stage adsorption tower is used to first remove nitrogen, carbon dioxide and water, if the adsorption pressure of the adsorption tower during the adsorption step of the first-stage adsorption tower is ≤0.04 MPa, a vacuuming step is added before the purge step of the first-stage adsorption tower, and the pressure after vacuuming is -0.06 to -0.05 MPa; or / and a compression step is added before the adsorption step of the second-stage adsorption tower, so that the adsorption pressure of the adsorption tower during the adsorption step is 0.6 to 1.0 MPa.

[0028] Beneficial effects:

[0029] The preparation method of the present invention is divided into three steps: after the raw air is pretreated and compressed, a pressure swing adsorption process is used in the first stage to separate and remove oxygen, carbon dioxide, water and part of the nitrogen to obtain a mixed gas rich in nitrogen and argon, or nitrogen, carbon dioxide, water and part of the oxygen are separated and removed to obtain a mixed gas rich in oxygen and argon; a pressure swing adsorption process is used in the second stage to separate nitrogen or oxygen from the gas subjected to pressure swing adsorption in the first stage to obtain a mixed gas rich in argon, at which time the argon contains trace oxygen; and a catalytic deoxidation process is used in the third stage to remove the trace oxygen in the argon and remove impurities, thereby obtaining high-purity argon.

[0030] The first and second pressure swing adsorption processes of the present invention can both employ two or more towers (two, three, or four towers) for adsorption, and the selection can be based on the gas (oxygen or nitrogen) primarily separated and removed in the first or second stage. If the gas separated and removed is primarily oxygen, two towers are generally used for adsorption, and the adsorption towers are filled with an adsorbent for oxygen adsorption, typically 4A or carbon molecular sieve. The adsorption pressure of the adsorption towers during the adsorption step is 0.6 to 1.0 MPa. If the gas separated and removed is primarily nitrogen, two or more towers (two, three, or four towers) can be employed for adsorption, and the adsorption towers are filled with an adsorbent for nitrogen adsorption, typically zeolite molecular sieves such as LiX, NaX, or CaX. The adsorption pressure of the adsorption towers during the adsorption step is 0.04 to 1.0 MPa gauge pressure. If the adsorption pressure is lower than 0.04 MPa, a vacuuming step is added before purging, and the pressure after vacuuming is -0.06 to -0.05 MPa.

[0031] Under the two-tower process, if the gas separated and removed is mainly oxygen, each adsorption tower undergoes the following steps in sequence within one adsorption cycle: adsorption, upper equalized pressure drop and upper and lower equalized pressure drop at the same time, inversion, purging, upper equalized pressure increase and upper and lower equalized pressure increase at the same time, and final increase; the adsorption tower that ends the adsorption state first performs upper equalized pressure drop and then performs upper and lower equalized pressure drop at the same time, and after the pressure equalization is completed, enters the inversion step, and then uses product gas to purge the adsorption tower from top to bottom, and then performs upper equalized pressure increase and upper and lower equalized pressure increase at the same time, and finally uses product gas for final increase, and then the adsorption tower enters the adsorption state again.

[0032] In a multi-tower process, if the gas being separated and removed is primarily nitrogen, each adsorption tower undergoes the following steps in sequence during an adsorption cycle: adsorption, upper pressure drop, inversion, purge, upper pressure increase, and final increase. The regenerated adsorption tower enters the adsorption state, and after adsorption, it enters the pressure drop step, then inversion. The adsorption tower is then purged from top to bottom with product gas. After the purge, the tower undergoes the pressure increase and final increase steps. After the final increase, the tower enters the adsorption state again. The upper pressure drop is repeated 1 to 5 times, and the upper pressure increase is repeated 1 to 5 times.

[0033] The third section of the present invention adopts a catalytic deoxidation process, in which the removal of oxygen from argon is the key to producing high-purity argon. The present invention uses carbon combustion deoxidation and then removes carbon dioxide, which has a high oxygen removal depth and can ensure the purity of the argon. First, the argon-rich gas passes through a transition metal-loaded carbon material and reacts with oxygen at 200-300°C to produce carbon dioxide. After the oxygen removal depth reaches the required level, the deoxidized argon enters an adsorption tower, where the carbon dioxide is adsorbed. After the carbon dioxide is removed, a product argon with a volume content of 99.99-99.999% is obtained (if the oxygen content after oxygen removal is 100ppm, the volume content of the obtained product argon is 99.99%; if the oxygen content after oxygen removal is 50ppm, the volume content of the obtained product argon is 99.995%; if the oxygen content after oxygen removal is 10ppm, the volume content of the obtained product argon is 99.999%). The inlet pressure of the third stage is 0.1-1.0 MPa, and the carbon dioxide removal process adopts pressure swing adsorption or temperature swing adsorption.

[0034] The method of the present invention can directly prepare argon anytime and anywhere in situations where argon is used, without being affected by the gas source or transportation distance, and argon is easily available. Because the content of argon in the air is very low, it is difficult to separate argon from the air. Argon is generally obtained by cryogenic methods. Cryogenic devices are large in size and cannot produce argon anytime and anywhere. For situations where argon is needed outdoors, the flexibility is insufficient. Furthermore, in addition to argon, the products obtained by the method of the present invention can also obtain crude nitrogen and crude oxygen, which can be further processed to obtain nitrogen products and oxygen products. This process method is also suitable for the recovery and purification of argon-rich tail gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The drawings and the accompanying drawings, which constitute part of this application, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. Among them:

[0036] Figure 1 This is a process flow chart provided for Example 1 of the present invention.

[0037] Among them, 11A is the first valve, 11B is the second valve, 12A is the third valve, 12B is the fourth valve, 13A is the fifth valve, 13B is the sixth valve, 14AB is the seventh valve, 15A is the eighth valve, 15B is the ninth valve, 21A is the tenth valve, 21B is the eleventh valve, 21C is the twelfth valve, 21D is the thirteenth valve, 22A is the fourteenth valve, 22B is the fifteenth valve, 22C is the sixteenth valve, 22D is the seventeenth valve, 23A is the eighteenth valve, 23B is the nineteenth valve, 23C is the twentieth valve, 23D is the twenty-first valve, 25A is the twenty-second valve, 25B is the twenty-third valve, 25C is the twenty-fourth valve, 25D is the twenty-fifth valve, KV7 is the twenty-sixth valve, 31A is the twenty-seventh valve, 31B is the twenty-eighth valve, 31C is the twenty-ninth valve, 32A is the thirtieth valve, 32B is the thirty-first valve door, 32C is the thirty-second valve, 31D is the thirty-third valve, 31E is the thirty-fourth valve, 32D is the thirty-fifth valve, 32E is the thirty-sixth valve, 33D is the thirty-seventh valve, 33E is the thirty-eighth valve, 35D is the thirty-ninth valve, 35E is the fortieth valve, 24A is the forty-first valve, 24B is the forty-second valve, 24C is the forty-third valve and 24D is the forty-fourth valve; 1A is the first adsorption tower, 1B is the second adsorption tower, 2A is the third adsorption tower, 2B is the fourth adsorption tower, 2C is the fifth adsorption tower, 2D is the sixth adsorption tower, 3D is the seventh adsorption tower, 3E is the eighth adsorption tower; 3A is the first deoxygenation tower, 3B is the second deoxygenation tower, 3C is the third deoxygenation tower; 3F is a heater; 3G is a muffler; Ⅰ is the first pipeline; Ⅱ is the second pipeline; Ⅲ is the third pipeline; a is the first branch; b is the second branch; c is the third branch; d is the fourth branch; e is the fifth branch. DETAILED DESCRIPTION

[0038] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention are within the scope of protection of the present invention.

[0039] The present invention will be described in detail below with reference to the embodiments. It should be noted that the embodiments and features of the embodiments of the present invention can be combined with each other without conflict.

[0040] The present invention addresses the problem that the current preparation of argon gas relies on cryogenic devices and cannot be prepared at any time. A method for preparing high-purity argon gas from air using a three-stage process is provided. The method uses air as a raw material and adopts a first-stage pressure swing adsorption device, a second-stage pressure swing adsorption device and a third-stage catalytic deoxidation device operated in series to prepare high-purity argon gas.

[0041] The first-stage pressure swing adsorption device includes a first-stage adsorption tower, and the second-stage pressure swing adsorption device includes a second-stage adsorption tower; the first-stage adsorption tower is used to remove oxygen, carbon dioxide and water to obtain an intermediate gas rich in nitrogen and argon; the second-stage adsorption tower is used to further remove nitrogen from the intermediate gas rich in nitrogen and argon flowing out of the first-stage adsorption tower to obtain an argon-rich gas, which also contains trace amounts of oxygen;

[0042] The third stage catalytic deoxidation device includes an oxygen removal system and a carbon dioxide removal system. The oxygen removal system uses carbon combustion to remove trace oxygen from the argon-rich gas to generate carbon dioxide; the carbon dioxide removal system further removes carbon dioxide generated from the oxygen removal system to obtain high-purity argon.

[0043] Each adsorption tower of the first section adsorption tower undergoes the steps of adsorption, upper equal pressure drop, upper and lower equal pressure drop simultaneously, inversion, purging, upper equal pressure increase, upper and lower equal pressure increase simultaneously, and final increase in one cycle. Each adsorption tower of the second section adsorption tower undergoes the steps of adsorption, upper equal pressure drop, inversion, purging, upper equal pressure increase, and final increase in one cycle.

[0044] In a preferred embodiment of the present invention, the first-stage adsorption tower includes two adsorption towers connected in parallel, and the second-stage adsorption tower includes two or more adsorption towers connected in parallel;

[0045] The pressure equalization times of the second-stage adsorption tower upper pressure drop step is 1 to 5 times, and the pressure equalization times of the second-stage adsorption tower upper pressure increase step is 1 to 5 times (for example, 1 time, 2 times, 3 times, 4 times or 5 times).

[0046] In a preferred embodiment of the present invention, the second-stage adsorption tower includes 2-4 (for example, 2, 3 or 4) adsorption towers connected in parallel with each other; the number of pressure equalization steps in the upper pressure drop step of the second-stage adsorption tower is 1, and the number of pressure equalization steps in the upper pressure increase step of the second-stage adsorption tower is 1 to 2 times (for example, 1 or 2).

[0047] The present invention adopts multiple adsorption towers connected in parallel. In the case of multiple adsorption towers, the number of pressure equalization times is also increased accordingly. Most of the pressure in the adsorption tower can be equalized to other towers, fully recovering the pressure of the adsorption tower. At the same time, the argon in the adsorption tower is also fully recovered, thereby improving the argon recovery rate and reducing energy consumption. At the same time, in the case of multiple towers, multiple towers can be used for simultaneous adsorption, thereby improving the process's ability to treat raw gas and increasing product production capacity.

[0048] In a preferred embodiment of the present invention, the total volume content of nitrogen and argon in the intermediate gas rich in nitrogen and argon is 95-99.5%; the volume content of argon in the argon-rich gas is 99-99.9%; and the volume content of argon in the high-purity argon gas is 99.99-99.999%.

[0049] In a preferred embodiment of the present invention, if the oxygen content of the argon-rich gas after passing through the oxygen removal system is 100 ppm, the volume content of argon in the high-purity argon gas is 99.99%; if the oxygen content of the argon-rich gas after passing through the oxygen removal system is 50 ppm, the volume content of argon in the high-purity argon gas is 99.995%; if the oxygen content of the argon-rich gas after passing through the oxygen removal system is 10 ppm, the volume content of argon in the high-purity argon gas is 99.999%.

[0050] In a preferred embodiment of the present invention, the adsorption pressure of the adsorption tower during the adsorption step in the first-stage adsorption tower is a gauge pressure of 0.6 to 1.0 MPa (for example, 0.6 MPa, 0.7 MPa, 0.8 MPa, 0.9 MPa or 1.0 MPa); the adsorption pressure of the adsorption tower during the adsorption step in the second-stage adsorption tower is a gauge pressure of 0.04 to 1.0 MPa (for example, 0.04 MPa, 0.08 MPa, 0.2 MPa, 0.4 MPa, 0.6 MPa, 0.8 MPa or 1.0 MPa); and the inlet pressure of the third-stage catalytic deoxidation device is a gauge pressure of 0.1 to 1.0 MPa (for example, 0.1 MPa, 0.2 MPa, 0.3 MPa, 0.4 MPa, 0.5 MPa, 0.6 MPa, 0.7 MPa, 0.8 MPa, 0.9 MPa or 1.0 MPa).

[0051] The adsorption pressure of the adsorption tower after the upper equalization pressure drop step of the first-stage adsorption tower is a gauge pressure of 0.3 to 0.5 MPa (for example, 0.3 MPa, 0.4 MPa or 0.5 MPa); the adsorption pressure of the adsorption tower after the upper equalization pressure drop step of the second-stage adsorption tower is a gauge pressure of 0.02 to 0.5 MPa (for example, 0.02 MPa, 0.04 MPa, 0.06 MPa, 0.08 MPa, 0.1 MPa, 0.3 MPa or 0.5 MPa).

[0052] The adsorption pressure of the present invention can ensure that the adsorbent or catalyst works under the optimal working conditions, which can not only achieve the best product production capacity, but also ensure the life of the adsorbent and reduce working energy consumption.

[0053] In a preferred embodiment of the present invention, the oxygen removal system and the carbon dioxide removal system are operated in series; the oxygen removal system includes a third-stage deoxygenation tower, and the third-stage deoxygenation tower includes 3 or more deoxygenation towers connected in series; the carbon dioxide removal system includes a third-stage adsorption tower, and the third-stage adsorption tower includes 2 adsorption towers connected in parallel.

[0054] Since the oxygen content in the argon entering the third section is relatively low, in order to ensure the depth of oxygen removal, multiple deoxidation towers need to be operated in series to extend the deoxidation reaction path and ensure the deoxidation depth. At least 3 deoxidation towers should be set up, or more.

[0055] The adsorbent filled in the adsorption tower of the carbon dioxide removal system is an adsorbent that adsorbs carbon dioxide.

[0056] In a preferred embodiment of the present invention, the adsorbent filled in the first-stage adsorption tower is 4A molecular sieve or carbon molecular sieve; the adsorbent filled in the second-stage adsorption tower is LiX, NaX or CaX zeolite molecular sieve; the adsorbent filled in the third-stage deoxygenation tower is a transition metal-loaded carbon material, and oxygen reacts with the transition metal-loaded carbon material to generate carbon dioxide.

[0057] The transition metal-loaded carbon material is any one of copper-containing carbon material, iron-containing carbon material, and nickel-containing carbon material, or a mixture of two or more thereof.

[0058] In a preferred embodiment of the present invention, the specific method of the upper equalized pressure drop and the simultaneous equalized pressure drop of the upper and lower parts is: the adsorption tower that completes the adsorption step is pressurized to the adsorption tower that needs to perform the equalized pressure increase step, so that the pressure of the adsorption tower in the equalized pressure drop step is reduced, and the pressure of the adsorption tower in the equalized pressure increase step is increased until the pressures of the two adsorption towers are consistent; wherein, the upper valve of the adsorption tower is first opened to perform the upper equalized pressure drop, so that the adsorption pressure of the adsorption tower that completes the adsorption step is reduced to a gauge pressure of 0.3 to 0.5 MPa (for example, 0.3 MPa, 0.4 MPa or 0.5 MPa); then the lower valve of the adsorption tower is opened to simultaneously perform the upper equalized pressure drop and the lower equalized pressure drop to make the pressures of the two adsorption towers consistent;

[0059] The specific method of increasing the upper pressure balance and increasing the upper and lower pressure balances simultaneously is as follows: after the purge step is completed, the adsorption tower is connected to the adsorption tower in the pressure reduction step to increase the pressure until the pressures of the two adsorption towers are consistent; wherein, the upper valve of the adsorption tower is first opened to increase the upper pressure balance, so that the adsorption pressure of the adsorption tower after the purge step is increased by 0.1-0.15MPa (for example, 0.1MPa, 0.12MPa or 0.15MPa); then the lower valve of the adsorption tower is opened to simultaneously increase the upper pressure balance and the lower pressure balance to make the pressures of the two adsorption towers consistent.

[0060] The working principle of the adsorption tower is that the adsorbent adsorbs impurity gases through micropores, and the product argon is enriched and flows out from the top of the tower. Therefore, as far as the adsorption tower is concerned, the space above the adsorption tower is filled with a considerable amount of argon. This part of the pressure needs to be recovered, so the upper pressure equalization is performed first. Since the time of each working section of a cycle is limited, only the upper pressure equalization cannot fully recover the pressure of the adsorption tower within a certain period of time. Therefore, after the argon in the upper space is recovered, the lower pressure equalization is opened, and the pressure of the two towers is balanced by the simultaneous pressure equalization of the upper and lower parts.

[0061] In a preferred embodiment of the present invention, if the first-stage adsorption tower is used to remove nitrogen, carbon dioxide, and water first, the type of adsorbent in the first-stage adsorption tower and the second-stage adsorption tower needs to be replaced. At the same time, the steps, number of adsorption towers, and adsorption pressure of each adsorption tower in a cycle need to be converted. The third-stage catalytic deoxygenation device and method remain unchanged.

[0062] At this time, the first-stage adsorption tower produces an intermediate gas rich in oxygen and argon, with a total volume content of oxygen and argon of 80-90%. The second-stage adsorption tower produces an argon-rich gas with a volume content of 99-99.9%. The third-stage catalytic deoxidation device produces high-purity argon with a volume content of 99.99-99.999%.

[0063] The adsorbent filled in the first adsorption tower is LiX, NaX or CaX zeolite molecular sieve; the adsorbent filled in the second adsorption tower is 4A molecular sieve or carbon molecular sieve;

[0064] Each adsorption tower of the first stage adsorption tower sequentially undergoes the steps of adsorption, upper uniform pressure drop, inversion, purging, upper uniform pressure increase, and final increase in one cycle. Each adsorption tower of the second stage adsorption tower sequentially undergoes the steps of adsorption, upper uniform pressure drop and upper and lower simultaneous pressure drop, inversion, purging, upper uniform pressure increase and upper and lower simultaneous pressure increase, and final increase in one cycle.

[0065] The first-stage adsorption tower includes two or more adsorption towers connected in parallel; the second-stage adsorption tower includes two adsorption towers connected in parallel; the pressure equalization number of the pressure drop step at the upper part of the first-stage adsorption tower is 1 to 5 times (for example, 1 time, 2 times, 3 times, 4 times or 5 times), and the pressure equalization number of the pressure increase step at the upper part of the first-stage adsorption tower is 1 to 5 times (for example, 1 time, 2 times, 3 times, 4 times or 5 times);

[0066] During the first adsorption step, the adsorption pressure of the adsorption tower is 0.04 to 1.0 MPa (e.g., 0.04 MPa, 0.08 MPa, 0.2 MPa, 0.4 MPa, 0.6 MPa, 0.8 MPa or 1.0 MPa) at a gauge pressure; during the second adsorption step, the adsorption pressure of the adsorption tower is 0.6 to 1.0 MPa (e.g., 0.6 MPa, 0.7 MPa, 0.8 MPa, 0.9 MPa or 1.0 MPa) at a gauge pressure. ); the adsorption pressure of the adsorption tower after the upper equalization pressure drop step of the first adsorption tower is a gauge pressure of 0.02 to 0.5 MPa (for example, 0.02 MPa, 0.04 MPa, 0.06 MPa, 0.08 MPa, 0.1 MPa, 0.3 MPa or 0.5 MPa); the adsorption pressure of the adsorption tower after the upper equalization pressure drop step of the second adsorption tower is a gauge pressure of 0.3 to 0.5 MPa (for example, 0.3 MPa, 0.4 MPa or 0.5 MPa).

[0067] In a preferred embodiment of the present invention, if the first-stage adsorption tower is used to first remove nitrogen, carbon dioxide and water, the first-stage adsorption tower includes 2-4 (for example, 2, 3 or 4) adsorption towers connected in parallel with each other; the number of pressure equalization steps in the upper pressure drop step of the first-stage adsorption tower is 1, and the number of pressure equalization steps in the upper pressure increase step of the second-stage adsorption tower is 1 to 2 times (for example, 1 or 2).

[0068] In a preferred embodiment of the present invention, when the first-stage adsorption tower is used to remove nitrogen, carbon dioxide and water first, if the adsorption pressure of the adsorption tower during the adsorption step of the first-stage adsorption tower is ≤0.04 MPa, a vacuuming step is added before the purge step of the first-stage adsorption tower, and the pressure after vacuuming is -0.06 to -0.05 MPa;

[0069] Or / and adding a compression step before the adsorption step of the second-stage adsorption tower so that the adsorption pressure of the adsorption tower during the adsorption step is 0.6 to 1.0 MPa (for example, 0.6 MPa, 0.7 MPa, 0.8 MPa, 0.9 MPa or 1.0 MPa).

[0070] In the preferred embodiment of the present invention, embodiment 1 of the present invention adopts Figure 1The device shown is used to prepare argon, and the device includes a first-stage pressure swing adsorption device, a second-stage pressure swing adsorption device and a third-stage catalytic deoxygenation device; the first-stage pressure swing adsorption device, the second-stage pressure swing adsorption device and the third-stage catalytic deoxygenation device are connected in series; the first-stage pressure swing adsorption device includes a first adsorption tower 1A and a second adsorption tower 1B connected in parallel; the second-stage pressure swing adsorption device includes a third adsorption tower 2A, a fourth adsorption tower 2B, a fifth adsorption tower 2C and a sixth adsorption tower 2D connected in parallel; the third-stage catalytic deoxygenation device includes an oxygen removal system and a carbon dioxide removal system, and the oxygen removal system and the carbon dioxide removal system are connected in series; the oxygen removal system includes a first deoxygenation tower 3A, a second deoxygenation tower 3B and a third deoxygenation tower 3C connected in series; the carbon dioxide removal system includes a seventh adsorption tower 3D and an eighth adsorption tower 3E connected in parallel.

[0071] The raw air enters the first adsorption tower 1A through the first valve 11A at the bottom of the first adsorption tower 1A, flows out from the third valve 12A at the top of the first adsorption tower 1A, and enters the second-stage pressure swing adsorption device; enters the second adsorption tower 1B through the second valve 11B at the bottom of the second adsorption tower 1B, flows out from the fourth valve 12B at the top of the second adsorption tower 1B, and enters the second-stage pressure swing adsorption device; a seventh valve 14AB is connected between the bottoms of the first adsorption tower 1A and the second adsorption tower 1B, and a fifth valve 13A and a sixth valve 13B connected in series are connected between the tops of the first adsorption tower 1A and the second adsorption tower 1B; an eighth valve 15A is connected to the bottom of the first adsorption tower 1A and is discharged directly to the air; a ninth valve 15B is connected to the bottom of the second adsorption tower 1B and is discharged directly to the air.

[0072] The intermediate gas flowing out of the first-stage pressure swing adsorption device enters the third adsorption tower 2A through the tenth valve 21A at the bottom of the third adsorption tower 2A, and flows out from the fourteenth valve 22A at the top of the adsorption tower; enters the fourth adsorption tower 2B through the eleventh valve 21B at the bottom of the fourth adsorption tower 2B, and flows out from the fifteenth valve 22B at the top of the adsorption tower; enters the fifth adsorption tower 2C through the twelfth valve 21C at the bottom of the fifth adsorption tower 2C, and flows out from the sixteenth valve 22C at the top of the adsorption tower; enters the sixth adsorption tower 2D through the thirteenth valve 21D at the bottom of the sixth adsorption tower 2D, and flows out from the seventeenth valve 22D at the top of the adsorption tower; the bottom of the third adsorption tower 2A is connected to the twenty-second valve 25A, which is directly discharged to the air; the bottom of the fourth adsorption tower 2B is connected to the twenty-third valve 25B, which is directly discharged to the air; the bottom of the fifth adsorption tower 2C is connected to the twenty-fourth valve 25C, which is directly discharged to the air; and the bottom of the sixth adsorption tower 2D is connected to the twenty-fifth valve 25D, which is directly discharged to the air.

[0073] The top of the third adsorption tower 2A is connected to the first pipeline I. Two branches are provided on the first pipeline I, one branch is the second pipeline II, and the other branch is the third pipeline III. The first pipeline I is provided with a fourteenth valve 22A and a twenty-seventh valve 31A connected in series. One end of the fourteenth valve 22A is connected to the top of the third adsorption tower 2A, and one end of the twenty-seventh valve 31A is connected to the bottom of the first deoxygenation tower 3A. The second pipeline II is provided with an eighteenth valve 23A and a twenty-first valve 23D which are connected in series. One end of the eighteenth valve 23A is connected to the first pipeline I, and one end of the twenty-first valve 23D is connected to the top pipeline of the sixth adsorption tower 2D. The second pipeline II is also provided with two branches: a fourth branch d and a fifth branch e. ​​The fourth branch d is provided with a nineteenth valve 23B. One end of the nineteenth valve 23B is connected to the second pipeline II, and the other end is connected to the top pipeline of the fourth adsorption tower 2B. The fifth branch e is provided with a twentieth valve 23C. One end of the twentieth valve 23C is connected to the second pipeline II, and the other end is connected to the top pipeline of the fifth adsorption tower 2C. The third pipeline III is provided with a forty-first valve 24A and a twenty-sixth valve KV7 connected in series. One end of the forty-first valve 24A is connected to the first pipeline I, and one end of the twenty-sixth valve KV7 is connected to the first pipeline I. The third pipeline III is also provided with three branches: a first branch a, a second branch b and a third branch c. The first branch a is provided with a forty-second valve 24B. One end of the forty-second valve 24B is connected to the third pipeline III, and the other end is connected to the top pipeline of the fourth adsorption tower 2B. The second branch b is provided with a forty-third valve 24C. One end of the forty-third valve 24C is connected to the third pipeline III, and the other end is connected to the top pipeline of the fifth adsorption tower 2C. The third branch c is provided with a forty-fourth valve 24D. One end of the forty-fourth valve 24D is connected to the third pipeline III, and the other end is connected to the top pipeline of the sixth adsorption tower 2D.

[0074] A fifteenth valve 22B is provided on the top pipeline of the fourth adsorption tower 2B, one end of the fifteenth valve 22B is connected to the first pipeline I, and the other end is connected to the fourth adsorption tower 2B; a sixteenth valve 22C is provided on the top pipeline of the fifth adsorption tower 2C, one end of the sixteenth valve 22C is connected to the first pipeline I, and the other end is connected to the fifth adsorption tower 2C; a seventeenth valve 22D is provided on the top pipeline of the sixth adsorption tower 2D, one end of the seventeenth valve 22D is connected to the first pipeline I, and the other end is connected to the sixth adsorption tower 2D.

[0075] The intermediate gas flowing out of the first pipeline I of the second-stage pressure swing adsorption device first passes through the oxygen removal system, enters the first deoxidation tower 3A through the 27th valve 31A at the bottom of the first deoxidation tower 3A, flows out through the 30th valve 32A at the top of the first deoxidation tower 3A, enters the second deoxidation tower 3B through the 28th valve 31B at the bottom of the second deoxidation tower 3B, flows out through the 31st valve 32B at the top of the second deoxidation tower 3B, then enters the third deoxidation tower 3C through the 29th valve 31C at the bottom of the third deoxidation tower 3C, and flows out through the 32nd valve 32C at the top of the third deoxidation tower 3C.

[0076] The intermediate gas flowing out of the oxygen removal system enters the seventh adsorption tower 3D through the 39th valve 35D at the bottom of the seventh adsorption tower 3D, passes through the 35th valve 32D at the top of the seventh adsorption tower 3D, and flows out through the discharge pipe of the product argon gas; enters the adsorption tower 3E through the 40th valve 35E at the bottom of the adsorption tower 3E, passes through the 36th valve 32E at the top of the adsorption tower 3E, and flows out through the discharge pipe of the product argon gas; the 39th valve 35D and the 40th valve 35E are connected in series, and a branch is provided on the pipeline between the 39th valve 35D and the 40th valve 35E, which is connected to the 32nd valve 32C Connection; the thirty-third valve 31D and the thirty-fourth valve 31E are connected in series between the bottom of the seventh adsorption tower 3D and the eighth adsorption tower 3E; the thirty-seventh valve 33D and the thirty-eighth valve 33E are connected in series between the top of the seventh adsorption tower 3D and the eighth adsorption tower 3E; a branch is also provided on the pipeline between the thirty-seventh valve 33D and the thirty-eighth valve 33E, the branch is connected to the upper end of the heater 3F, and the lower end of the heater 3F is connected to the exhaust pipe of the product argon gas; a branch is also provided on the pipeline between the thirty-third valve 31D and the thirty-fourth valve 31E, the branch is connected to the muffler 3G.

[0077] The method for preparing high-purity argon from air using a three-stage method of the present invention is described in detail below through specific examples.

[0078] Example 1

[0079] The raw gas in this embodiment is air, and its composition is as shown in Table 1:

[0080] Table 1

[0081] Components <![CDATA[N2]]> <![CDATA[O2]]> Ar <![CDATA[CO2]]> other Σ Concentration% (V / V) 78.03 20.95 0.93 0.03 0.06 100

[0082] Temperature: room temperature; Pressure: 0.7MPa

[0083] like Figure 1The figure shows a process flow chart of Example 1 of the present invention. In which, the first stage pressure swing adsorption device, the second stage pressure swing adsorption device and the third stage catalytic deoxygenation device are connected in series; the first stage pressure swing adsorption device includes two parallel adsorption towers: the first adsorption tower 1A and the second adsorption tower 1B, and the first valve 11A, the second valve 11B, the third valve 12A, the fourth valve 12B, the fifth valve 13A, the sixth valve 13B, the seventh valve 14AB, the eighth valve 15A and the ninth valve 15B; the second stage pressure swing adsorption device includes four parallel adsorption towers: the first adsorption tower 1A and the second adsorption tower 1B. The third adsorption tower 2A, the fourth adsorption tower 2B, the fifth adsorption tower 2C and the sixth adsorption tower 2D, and the tenth valve 21A, the eleventh valve 21B, the twelfth valve 21C, the thirteenth valve 21D, the fourteenth valve 22A, the fifteenth valve 22B, the sixteenth valve 22C, the seventeenth valve 22D, the eighteenth valve 23A, the nineteenth valve 23B, the twentieth valve 23C, the twenty-first valve 23D, the forty-first valve 24A, the forty-second valve 24B, the forty-third valve 24 C, the 44th valve 24D, the 22nd valve 25A, the 23rd valve 25B, the 24th valve 25C, the 25th valve 25D and the 26th valve KV7; the third-stage catalytic deoxygenation device includes an oxygen removal system and a carbon dioxide removal system, which are connected in series; the oxygen removal system includes three deoxygenation towers connected in series: the first deoxygenation tower 3A, the second deoxygenation tower 3B and the third deoxygenation tower 3C, and the 27th valve 31A, the 28th valve 31B, the 29th valve 31C, the 30th valve 32A, the 31st valve 32B and the 32nd valve 32C; the carbon dioxide removal system includes a heater 3F, a muffler 3G, two parallel adsorption towers: the 7th adsorption tower 3D and the 8th adsorption tower 3E, and the 33rd valve 31D, the 34th valve 31E, the 35th valve 32D, the 36th valve 32E, the 37th valve 33D, the 38th valve 33E, the 39th valve 35D and the 40th valve 35E. Figure 1 The timing charts between the valves are shown in Table 2 to Table 4.

[0084] Table 2

[0085]

[0086] Table 3

[0087]

[0088] Table 4

[0089]

[0090] A method for preparing high-purity argon from air using a three-stage process. After pretreatment and compression of the raw air, the first stage adopts a two-tower pressure swing adsorption process. The adsorption towers are filled with carbon molecular sieves to remove most of the oxygen, carbon dioxide, water and part of the nitrogen to obtain a nitrogen- and argon-rich mixed gas, which enters the second stage. The second stage adopts a four-tower pressure swing adsorption process. The towers are filled with NaX to perform a coarse separation of nitrogen and argon from the gas obtained in the first stage of pressure swing adsorption, remove most of the nitrogen, and obtain a mixed gas of argon and trace oxygen, which enters the third stage. The third stage adopts catalytic deoxidation. The trace oxygen in the argon passes through deoxidation towers 3A to 3C (carbon materials loaded with transition metals) to react with oxygen at 200 to 300°C, and the carbon is burned and removed. The generated carbon dioxide is then removed by the adsorption tower, thereby obtaining high-purity argon.

[0091] 1. The volume content of nitrogen and argon obtained at the outlet of the first pressure swing adsorption stage is 99.5%. Two towers (the first adsorption tower 1A and the second adsorption tower 1B) are used for adsorption, and the two-pass pressure equalization method is adopted. The specific steps are as follows (taking the first adsorption tower 1A as an example):

[0092] (1) Adsorption

[0093] Air is compressed to 0.7 MPa and fed from the bottom through the first valve 11A into the first adsorption tower 1A in the adsorption step. The adsorbent in the first adsorption tower 1A adsorbs carbon dioxide, moisture, and most of the oxygen. The unabsorbed nitrogen, argon, and trace oxygen flow out from the top of the tower through the third valve 12A and enter the second-stage pressure swing adsorption device through any one of the tenth valve 21A, the eleventh valve 21B, the twelfth valve 21C, and the thirteenth valve 21D. When the adsorbent in the first adsorption tower 1A reaches saturation, the first valve 11A and the third valve 12A are closed, the air supply is stopped, and the adsorption process in the first adsorption tower 1A ends.

[0094] (2) Upper pressure drop and upper and lower pressure drop simultaneously

[0095] After the adsorption step is completed, some argon-containing gas is present in the dead space of the first adsorption tower 1A, which needs to be recovered. The argon content in the upper part of the first adsorption tower 1A is higher than that in the lower part. Therefore, the upper gas is recovered first. The fifth valve 13A and the sixth valve 13B are opened to perform an upper pressure drop. The argon-containing gas in the dead space of the first adsorption tower 1A is sent to the second adsorption tower 1B through the upper pressure-equalizing pipe, that is, the first adsorption tower 1A and the second adsorption tower 1B are pressure-equalized. When the adsorption pressure in the first adsorption tower 1A drops to 0.4 MPa, the seventh valve 14AB is opened to perform upper and lower pressure drops simultaneously. After the pressures of the first adsorption tower 1A and the second adsorption tower 1B are equalized, the pressure drop step is terminated. That is, the pressure-equalizing step is repeated twice.

[0096] (3) Reverse

[0097] After step (2) is completed, there is still a small amount of pressure in the first adsorption tower 1A. Through decompression desorption, the oxygen-rich gas released from the adsorbent micropores passes through the eighth valve 15A and is directly released into the air naturally. At the same time, the second adsorption tower 1B enters the adsorption state.

[0098] (4) Purge

[0099] After the inversion is completed, the gas gauge pressure in the first adsorption tower 1A is 0. The product gas from the first section is used to purge the first adsorption tower 1A from top to bottom through the fifth valve 13A to purge the remaining oxygen, moisture and carbon dioxide in the adsorbent micropores in the first adsorption tower 1A, so that the adsorbent in the first adsorption tower 1A is completely regenerated. At the same time, the second adsorption tower 1B is in an adsorption state.

[0100] (5) Upper pressure rise and upper and lower pressure rise simultaneously

[0101] The first adsorption tower 1A, which has completed the purge step, and the second adsorption tower 1B, which has completed the adsorption step, are subjected to upper equalization pressure increase through the fifth valve 13A and the sixth valve 13B. The argon-containing gas in the dead space of the second adsorption tower 1B is fed into the first adsorption tower 1A through the upper equalization pipe. After the adsorption pressure of the first adsorption tower 1A increases by 0.1 MPa, the seventh valve 14AB is opened to simultaneously perform upper and lower equalization pressure increases. After the pressures are equalized (i.e., the pressure of the first adsorption tower 1A is consistent with that of the product gas in the first stage), the equalization is terminated. This means that the equalization step is repeated twice.

[0102] (6) Final Ascension

[0103] After finishing step (5), the first adsorption tower 1A is finally lifted by using the product gas of the first section through the third valve 12A. Finally, the first adsorption tower 1A enters the adsorption state of the next cycle, and this cycle repeats.

[0104] The steps and sequence of the second adsorption tower 1B in this section are exactly the same as those of the first adsorption tower 1A, except that they are staggered in time, and will not be summarized here.

[0105] 2. The volume content of argon obtained in the second stage of pressure swing adsorption is 99.9%. Four towers (the third adsorption tower 2A, the fourth adsorption tower 2B, the fifth adsorption tower 2C and the sixth adsorption tower 2D) are used for single-tower adsorption and one-time pressure equalization. The specific steps are as follows (taking the third adsorption tower 2A as an example):

[0106] (1) Adsorption

[0107] The product gas of the first section, at a pressure of approximately 0.5 MPa, enters the third adsorption tower 2A from bottom to top through the tenth valve 21A. The adsorbent NaX in the third adsorption tower 2A has a much higher adsorption capacity for nitrogen than argon, so most of the nitrogen enters the micropores of the adsorbent NaX. The product gas of the second section flows out through the fourteenth valve 22A and then enters the first deoxidation tower 3A through the twenty-seventh valve 31A. When the adsorbent in the third adsorption tower 2A reaches saturation, the tenth valve 21A and the fourteenth valve 22A are closed, gas intake is stopped, and adsorption ends.

[0108] (2) Average pressure drop

[0109] After the adsorption is completed, a lot of argon-containing gas remains in the dead space formed by the adsorbent particles in the third adsorption tower 2A, which needs to be recovered. The argon concentration in the upper part is relatively high, so an equal pressure drop is performed first. The eighteenth valve 23A and the nineteenth valve 23B are opened to send the argon-containing gas in the dead space of the third adsorption tower 2A into the fourth adsorption tower 2B through the upper equal pressure pipe. When the adsorption pressure in the third adsorption tower 2A drops to 0.3 MPa, the equal pressure drop step is completed.

[0110] (3) Reverse

[0111] After step (2) is completed, the remaining gas in the third adsorption tower 2A is mainly nitrogen, which has no recovery value. The pressure in the third adsorption tower 2A is released to normal pressure through the lower 22nd valve 25A and the reverse pipeline.

[0112] (4) Purge

[0113] Adjust the opening of the twenty-sixth valve kV7, and use the second-stage product gas to pass through the twenty-sixth valve KV7 and the forty-first valve 24A to purge the third adsorption tower 2A, so that the adsorbent in the third adsorption tower 2A is regenerated.

[0114] (5) The first upper pressure rise

[0115] Open the eighteenth valve 23A, close the twenty-second valve 25A, and use the top gas of the fifth adsorption tower 2C (the product gas of the second stage) to equalize the pressure of the regenerated third adsorption tower 2A. After the adsorption pressure of the third adsorption tower 2A increases by 0.1 MPa, the first upper equalization pressure increase is completed.

[0116] (6) Second upper pressure rise

[0117] After the first upper pressure equalization is completed, the second section product gas is used from the upper part of the sixth adsorption tower 2D through the twenty-first valve 23D and the eighteenth valve 23A to again equalize the pressure of the third adsorption tower 2A. After the pressure is balanced (that is, the pressure of the third adsorption tower 2A is consistent with that of the second section product gas), the pressure equalization is ended.

[0118] (7) Final Ascension

[0119] After step (6) is completed, the tenth valve 21A is opened, and the second stage product gas is used to perform a final lift on the third adsorption tower 2A, and then the third adsorption tower 2A enters the adsorption state again.

[0120] The steps and sequence of the other adsorption towers in this section are exactly the same as those of the third adsorption tower 2A, except that they are staggered in time, and will not be summarized here.

[0121] 3. The third stage is to burn and remove trace oxygen, and the volume content of the obtained argon is 99.999%. The carbon combustion deoxygenation + temperature swing adsorption (TSA) method is used to remove carbon dioxide. The specific steps are as follows:

[0122] (1) Carbon combustion deoxidation

[0123] After two stages of pressure swing adsorption, the argon gas still contains trace amounts of oxygen, which needs to be removed. This oxygen-containing argon gas, at a pressure of 0.5 MPa, enters the first deoxidation tower 3A through valve 27 31A, then through valves 30 32A and 31B into the second deoxidation tower 3B. It then enters the third deoxidation tower 3C through valves 31B and 31C. After passing through the transition metal-loaded carbon material, the oxygen reacts with the carbon to produce carbon dioxide.

[0124] (2) Removal of carbon dioxide

[0125] The deoxygenated argon gas (oxygen content of 10 ppm) enters the seventh adsorption tower 3D through the 32nd valve 32C and the 39th valve 35D. After carbon dioxide is adsorbed, the product argon gas flows out through the 35th valve 32D. Simultaneously, a channel of product argon gas is separated and enters the heater 3F from the bottom. The heated product argon gas passes through the 38th valve 33E and enters the eighth adsorption tower 3E from top to bottom for purging. The purged waste gas is discharged through the 34th valve 31E through a muffler. After a period of time, the regeneration of the eighth adsorption tower 3E is completed. The 38th valve 33E is closed, and the 36th valve 32E is opened to pressurize the eighth adsorption tower 3E. After the seventh adsorption tower 3D is saturated with adsorption, the 39th valve 35D and the 35th valve 32D are closed, and the 40th valve 35E and the 36th valve 32E are opened to switch the operation to the eighth adsorption tower 3E. The eighth adsorption tower 3E now enters the adsorption operating state, and ultimately, an argon product with a volume content of 99.999% is obtained.

[0126] Example 2

[0127] The raw gas in this embodiment is air, and its composition is shown in Table 5:

[0128] Table 5

[0129] Components <![CDATA[N2]]> <![CDATA[O2]]> Ar <![CDATA[CO2]]> other Σ Concentration% (V / V) 78.03 20.95 0.93 0.03 0.06 100

[0130] Gas temperature: room temperature; gas pressure: 0.05MPa

[0131] The difference between this embodiment and embodiment 1 is that the first stage pressure swing adsorption process mainly removes nitrogen and adopts two towers for adsorption, and the second stage pressure swing adsorption process mainly removes oxygen and adopts two towers for adsorption. The other process flows are the same as those in embodiment 1. Figure 1 The same; and the pressure of the raw air is lower at 0.05 MPa. Therefore, a vacuum step is added before the purge step of the first stage pressure swing adsorption, and the adsorption tower of the first stage pressure swing adsorption can only be filled with LiX (Lix has low strength, is suitable for adsorption work under low pressure, and has good adsorption effect).

[0132] A method for preparing high-purity argon from air using a three-stage process. After pretreatment and compression of raw air, the first stage adopts a two-tower pressure swing adsorption process. The adsorption tower is filled with LiX to remove nitrogen, carbon dioxide, water and part of oxygen to obtain a mixed gas of oxygen and argon, which enters the second stage. The second stage adopts a two-tower pressure swing adsorption process. After the gas from the first stage is compressed, the oxygen and argon are roughly separated. The adsorption tower is filled with 4A molecular sieve. Oxygen can enter the 4A molecular sieve faster than argon, so most of the oxygen is removed to obtain a mixed gas of argon and a small amount of oxygen, which enters the third stage. The third stage adopts catalytic deoxidation to remove trace oxygen in the argon through carbon combustion and remove the generated carbon dioxide, thereby obtaining high-purity argon.

[0133] 1. The volume content of oxygen and argon obtained at the outlet of the first pressure swing adsorption is 80%. A two-tower (first adsorption tower and second adsorption tower) adsorption method is adopted. The specific steps are as follows (taking the first adsorption tower as an example):

[0134] (1) Adsorption

[0135] The air is compressed to 0.05MPa and fed from the bottom into the first adsorption tower in the adsorption step. The first adsorption tower is filled with LiX molecular sieve, and carbon dioxide, moisture and most of the nitrogen are adsorbed. The unabsorbed nitrogen, oxygen and argon flow out from the top of the tower. When the adsorbent in the first adsorption tower is saturated with adsorption, the air supply is stopped and the adsorption process of the first adsorption tower is completed.

[0136] (2) Average pressure drop

[0137] After the adsorption step is completed, there is some argon-containing gas in the dead space of the first adsorption tower. In order to fully recover the argon gas, it is necessary to perform a uniform pressure drop on the first adsorption tower. The uniform pressure drop is performed from the top of the tower, and the argon-containing gas in the dead space of the first adsorption tower is sent to the second adsorption tower. When the adsorption pressure in the first adsorption tower drops to 0.03MPa, the uniform pressure drop step is completed.

[0138] (3) Reverse placement and vacuuming

[0139] After the pressure drop is completed, there is still a small amount of pressure in the first adsorption tower, which is directly reversed to the air through the lower reverse discharge port and evacuated by a vacuum pump to ensure the regeneration effect of the adsorbent. The pressure after evacuation is about -0.05MPa.

[0140] (4) Purge

[0141] After the vacuuming is completed, the product gas from the first stage is used to purge the first adsorption tower from top to bottom to purge the remaining nitrogen, moisture and carbon dioxide in the adsorbent micropores, so that the adsorbent is completely regenerated.

[0142] (5) Upper pressure rise

[0143] The product gas of the first stage is used to evenly increase the pressure of the first adsorption tower that has completed the purge step, and the pressure equalization is completed after the pressure is balanced.

[0144] (6) Final Ascension

[0145] After the pressure equalization step is completed, the first adsorption tower is finally raised using the first section of product gas, and finally the first adsorption tower enters the adsorption state again.

[0146] The steps and sequence of the other adsorption towers in this section are exactly the same as those of the first adsorption tower, except that they are staggered in time, and will not be summarized here.

[0147] 2. The volume content of argon obtained in the second stage of pressure swing adsorption is 99.5%. Two-tower adsorption (the third adsorption tower and the fourth adsorption tower) and a secondary pressure equalization method are used. The specific steps are as follows (taking the third adsorption tower as an example):

[0148] (1) Adsorption

[0149] The product gas in the first section is about 0.03Mpa, which is pressurized to 0.6MPa by the compressor and enters the third adsorption tower from bottom to top. Oxygen can enter the adsorbent micropores faster than argon. After the third adsorption tower is saturated with adsorption, the air intake is stopped and the adsorption ends.

[0150] (2) Upper pressure drop and upper and lower pressure drop simultaneously

[0151] After the adsorption is completed, a lot of argon-containing gas remains in the dead space formed by the adsorbent particles of the third adsorption tower, which needs to be recovered. The argon concentration in the upper part is relatively high, so the upper pressure drop is performed first, and the argon-containing gas in the dead space of the third adsorption tower is sent to the fourth adsorption tower through the upper part. When the adsorption pressure in the third adsorption tower drops to 0.4MPa, the lower valve is opened, and the upper and lower pressure drops are performed at the same time. After the pressures of the third adsorption tower and the fourth adsorption tower are balanced, the pressure equalization step is ended.

[0152] (3) Reverse

[0153] After the third adsorption tower completes step (2), the pressure inside the tower is released to normal pressure through the lower inverted pipeline.

[0154] (4) Purge

[0155] The product gas from the second section is used to purge the third adsorption tower, thereby completing the regeneration of the third adsorption tower.

[0156] (5) Pressurization

[0157] In order to ensure that the adsorption tower reaches the optimal adsorption pressure as quickly as possible, a pressurization step is added, and the product gas from the second stage is used to pressurize the regenerated third adsorption tower.

[0158] (6) Upper pressure rise and upper and lower pressure rise simultaneously

[0159] After step (5) is completed, the fourth adsorption tower completes the adsorption step, and the upper pressure is increased first, and the argon-containing gas in the dead space of the fourth adsorption tower is sent to the third adsorption tower through the upper part. After the adsorption pressure of the third adsorption tower increases by 0.1 MPa, the lower valve is opened, and the upper and lower pressures are increased at the same time. After the pressure is balanced, the pressure equalization is completed.

[0160] (7) Final Ascension

[0161] After step (6) is completed, the second stage product gas is used to perform a final lift on the third adsorption tower, and then the third adsorption tower enters the adsorption state again.

[0162] The steps and sequence of the other adsorption towers in this section are exactly the same as those of the third adsorption tower, except that they are staggered in time, and will not be summarized here.

[0163] 3. The third stage is to burn and remove trace oxygen, and the volume content of the obtained argon is 99.999%. The carbon addition combustion deoxygenation + TSA removal of carbon dioxide process is adopted (the same as the third stage of Example 1, see Figure 1 The third stage catalytic deoxidation device) has the following specific steps:

[0164] (1) Carbon combustion deoxidation

[0165] After two stages of pressure swing adsorption, the argon gas still contains trace amounts of oxygen, which needs to be removed. This oxygen-containing argon gas, at a pressure of 0.5 MPa, enters the first deoxidation tower 3A through valve 27 31A, then through valves 30 32A and 31B into the second deoxidation tower 3B. It then enters the third deoxidation tower 3C through valves 31B and 31C. After passing through the transition metal-loaded carbon material, the oxygen reacts with the carbon to produce carbon dioxide.

[0166] (2) Removal of carbon dioxide

[0167] The deoxygenated argon gas (oxygen content of 10 ppm) enters the seventh adsorption tower 3D through the 32nd valve 32C and the 39th valve 35D. After carbon dioxide is adsorbed, the product argon gas flows out through the 35th valve 32D. Simultaneously, a channel of product argon gas is separated and enters the heater 3F from the bottom. The heated product argon gas passes through the 38th valve 33E and enters the eighth adsorption tower 3E from top to bottom for purging. The purged waste gas is discharged through the 34th valve 31E through a muffler. After a period of time, the regeneration of the eighth adsorption tower 3E is completed. The 38th valve 33E is closed, and the 36th valve 32E is opened to pressurize the eighth adsorption tower 3E. After the seventh adsorption tower 3D is saturated with adsorption, the 39th valve 35D and the 35th valve 32D are closed, and the 40th valve 35E and the 36th valve 32E are opened to switch the operation to the eighth adsorption tower 3E. The eighth adsorption tower 3E now enters the adsorption operating state, and ultimately, an argon product with a volume content of 99.999% is obtained.

[0168] Example 3

[0169] The raw gas of the present invention is air, and its composition is as shown in Table 6:

[0170] Table 6

[0171] Components <![CDATA[N2]]> <![CDATA[O2]]> Ar <![CDATA[CO2]]> other Σ Concentration% (V / V) 78.03 20.95 0.93 0.03 0.06 100

[0172] Temperature: room temperature; Pressure: 0.6MPa

[0173] The difference between this embodiment and embodiment 1 is that the first stage pressure swing adsorption process mainly removes nitrogen and adopts 4 towers for adsorption, and the second stage pressure swing adsorption process mainly removes oxygen and adopts 2 towers for adsorption. The other process flows are the same as those in embodiment 1. Figure 1 same.

[0174] The present invention discloses a method for preparing high-purity argon from air by a non-cryogenic method. After raw air is pretreated and compressed, a multi-tower pressure swing adsorption process is adopted in the first stage. The adsorption tower is filled with NaX to remove nitrogen, carbon dioxide, water and part of oxygen to obtain a mixed gas of oxygen and argon, which enters the second stage. The second stage adopts a two-tower pressure swing adsorption process. The tower is filled with 4A molecular sieve. The gas obtained by the pressure swing adsorption in the first stage is subjected to a coarse separation of oxygen and argon to remove most of the oxygen to obtain a mixed gas of argon and trace oxygen, which enters the third stage. The third stage adopts catalytic deoxidation to remove the trace oxygen in the argon by carbon combustion and remove the generated carbon dioxide, thereby obtaining high-purity argon.

[0175] 1. The volume content of oxygen and argon obtained at the outlet of the first stage pressure swing adsorption is 90%. A four-tower (first adsorption tower, second adsorption tower, third adsorption tower and fourth adsorption tower) adsorption method is adopted. The specific steps are as follows (taking the first adsorption tower as an example):

[0176] (1) Adsorption

[0177] The air is compressed to 0.6MPa and enters the first adsorption tower from bottom to top through the valve. The adsorbent NaX in the first adsorption tower has a much higher adsorption capacity for nitrogen than argon, so most of the nitrogen enters the micropores of the adsorbent NaX. The first section of product gas flows out through the valve. After the adsorbent in the first adsorption tower is saturated with adsorption, the valve is closed, the air intake is stopped, and the adsorption ends.

[0178] (2) Average pressure drop

[0179] After the adsorption is completed, a lot of argon-containing gas remains in the dead space formed by the adsorbent particles of the first adsorption tower, which needs to be recovered. The argon concentration in the upper part is relatively high, so a balanced pressure drop is performed first. The upper valve is opened to send the argon-containing gas in the dead space of the first adsorption tower into the second adsorption tower through the upper part. When the adsorption pressure in the first adsorption tower drops to 0.3MPa, the balanced pressure drop step is completed.

[0180] (3) Reverse

[0181] After step (2) is completed, the pressure inside the first adsorption tower is released to normal pressure through the lower valve and the reverse pipeline.

[0182] (4) Purge

[0183] The product gas from the second stage is used to purge the first adsorption tower, so that the first adsorption tower is regenerated.

[0184] (5) The first upper pressure rise

[0185] The top gas of the third adsorption tower (the first stage product gas) is used to perform pressure equalization on the regenerated first adsorption tower. After the adsorption pressure of the first adsorption tower increases by 0.1 MPa, the first upper pressure equalization is completed.

[0186] (6) Second upper pressure rise

[0187] After step (5) is completed, the first stage product gas is used from the upper part of the fourth adsorption tower to increase the pressure of the first adsorption tower, and the pressure equalization is completed after the pressure is balanced.

[0188] (7) Final Ascension

[0189] After step (6) is completed, the first adsorption tower is finally lifted using the first stage product gas, and then the first adsorption tower enters the adsorption state again.

[0190] The steps and sequence of the other adsorption towers in this section are exactly the same as those of the first adsorption tower, except that they are staggered in time, and will not be summarized here.

[0191] 2. The volume content of argon obtained by the second stage pressure swing adsorption is 99.9%. Two towers (the fifth adsorption tower and the sixth adsorption tower) are used for two-time pressure equalization adsorption. The specific steps are as follows (taking the fifth adsorption tower as an example):

[0192] (1) Adsorption

[0193] The product gas in the first section is about 0.5MPa and enters the fifth adsorption tower from bottom to top through the valve. The adsorbent 4A molecular sieve has a much higher adsorption rate for oxygen than argon, so most of the oxygen enters the micropores of the adsorbent 4A molecular sieve. After the fifth adsorption tower is saturated with adsorption, the air intake is stopped and the adsorption ends.

[0194] (2) Upper pressure drop and upper and lower pressure drop simultaneously

[0195] After the adsorption is completed, a lot of argon-containing gas remains in the dead space formed by the adsorbent particles of the fifth adsorption tower, which needs to be recovered. The argon concentration in the upper part is relatively high, so the upper pressure drop is performed first, and the argon-containing gas in the dead space of the fifth adsorption tower is sent to the sixth adsorption tower through the upper part. When the adsorption pressure in the fifth adsorption tower drops to 0.3MPa, the upper and lower pressure drops are performed at the same time. After the pressures of the fifth adsorption tower and the sixth adsorption tower are balanced, the pressure equalization step is ended.

[0196] (3) Reverse

[0197] After the fifth adsorption tower completes step (2), the pressure inside the tower is released to normal pressure through the lower inverted pipeline.

[0198] (4) Purge

[0199] The fifth adsorption tower is purged with the product gas from the second stage to complete the regeneration of the fifth adsorption tower.

[0200] (5) Pressurization

[0201] In order to make the adsorption tower reach the optimal adsorption pressure as quickly as possible, a pressurization step is added, and the product gas from the second stage is used to pressurize the regenerated fifth adsorption tower.

[0202] (6) Upper pressure rise and upper and lower pressure rise simultaneously

[0203] After step (5) is completed, the sixth adsorption tower completes the adsorption step, and the upper pressure equalization is first performed, and the argon-containing gas in the dead space of the sixth adsorption tower is sent to the fifth adsorption tower through the upper part. After the adsorption pressure of the fifth adsorption tower increases by 0.1MPa, the lower pressure equalization valve is opened, and the upper and lower pressure equalization are performed at the same time. After the pressures of the fifth adsorption tower and the sixth adsorption tower are balanced, the pressure equalization is completed.

[0204] (7) Final Ascension

[0205] After step (6) is completed, the fifth adsorption tower is finally lifted using the second stage product gas, and then the fifth adsorption tower enters the adsorption state again.

[0206] The steps and sequence of the other adsorption towers in this section are exactly the same as those of the fifth adsorption tower, except that they are staggered in time, and will not be summarized here.

[0207] 3. The third stage is to burn and remove trace oxygen, and the volume content of the obtained argon is 99.999%. The carbon addition combustion deoxygenation + TSA removal of carbon dioxide process is adopted (the same as the third stage of Example 1, see Figure 1 The third stage catalytic deoxidation device) has the following specific steps:

[0208] (1) Carbon combustion deoxidation

[0209] After two stages of pressure swing adsorption, the argon gas still contains trace amounts of oxygen, which needs to be removed. This oxygen-containing argon gas, at a pressure of 0.4 MPa, enters the first deoxidation tower 3A through valve 27 31A, then through valves 30 32A and 31B into the second deoxidation tower 3B. It then enters the third deoxidation tower 3C through valves 31B and 31C, passing through the transition metal-loaded carbon material. The oxygen reacts with the carbon to produce carbon dioxide.

[0210] (2) Removal of carbon dioxide

[0211] The deoxygenated argon gas (oxygen content of 10 ppm) enters the seventh adsorption tower 3D through the 32nd valve 32C and the 39th valve 35D. After carbon dioxide is adsorbed, the product argon gas flows out through the 35th valve 32D. Simultaneously, a channel of product argon gas is separated and enters the heater 3F from the bottom. The heated product argon gas passes through the 38th valve 33E and enters the eighth adsorption tower 3E from top to bottom for purging. The purged waste gas is discharged through the 34th valve 31E through a muffler. After a period of time, the regeneration of the eighth adsorption tower 3E is completed. The 38th valve 33E is closed, and the 36th valve 32E is opened to pressurize the eighth adsorption tower 3E. After the seventh adsorption tower 3D is saturated with adsorption, the 39th valve 35D and the 35th valve 32D are closed, and the 40th valve 35E and the 36th valve 32E are opened to switch the operation to the eighth adsorption tower 3E. The eighth adsorption tower 3E now enters the adsorption operating state, and ultimately, an argon product with a volume content of 99.999% is obtained.

[0212] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A method for preparing high-purity argon from air using a three-stage process, characterized in that: The method uses air as a raw material and directly prepares argon anytime and anywhere in situations where argon is used. A first-stage pressure swing adsorption device, a second-stage pressure swing adsorption device, and a third-stage catalytic deoxidation device are operated in series to prepare high-purity argon. The first-stage pressure swing adsorption device includes a first-stage adsorption tower, and the second-stage pressure swing adsorption device includes a second-stage adsorption tower; the first-stage adsorption tower is used to remove oxygen, carbon dioxide, and water to obtain an intermediate gas rich in nitrogen and argon; the second-stage adsorption tower is used to further remove nitrogen from the intermediate gas rich in nitrogen and argon flowing out of the first-stage adsorption tower to obtain an argon-rich gas, which also contains a trace amount of oxygen; the total volume content of nitrogen and argon in the intermediate gas rich in nitrogen and argon is 95-99.5%; the volume content of argon in the argon-rich gas is 99-99.9%; The third stage catalytic deoxidation device includes an oxygen removal system and a carbon dioxide removal system. The oxygen removal system uses carbon combustion to remove trace oxygen from the argon-rich gas to generate carbon dioxide. The carbon dioxide removal system further removes carbon dioxide generated from the oxygen removal system to obtain high-purity argon. The volume content of argon in the high-purity argon is 99.99-99.999%. Each adsorption tower of the first stage adsorption tower undergoes the steps of adsorption, upper pressure drop, upper and lower pressure drop simultaneously, inversion, purge, upper pressure increase, upper and lower pressure increase simultaneously, and final increase in one cycle. Each adsorption tower of the second stage adsorption tower undergoes the steps of adsorption, upper pressure drop, inversion, purge, upper pressure increase, and final increase in one cycle. The specific method of achieving the equalized pressure drop at the upper part and the equalized pressure drop at the upper and lower parts of the first-stage adsorption tower is as follows: the adsorption tower that has completed the adsorption step is pressurized to the adsorption tower that needs to perform the equalized pressure increase step, so that the pressure of the adsorption tower in the equalized pressure drop step is reduced, and the pressure of the adsorption tower in the equalized pressure increase step is increased, until the pressures of the two adsorption towers are consistent; wherein, the upper valve of the adsorption tower is first opened to perform the upper equalized pressure drop, so that the adsorption pressure of the adsorption tower that has completed the adsorption step is reduced to a gauge pressure of 0.3-0.5 MPa; then, the lower valve of the adsorption tower is opened to simultaneously perform the upper equalized pressure drop and the lower equalized pressure drop, so that the pressures of the two adsorption towers are consistent; The specific method for increasing the upper pressure of the first-stage adsorption tower and increasing the upper and lower pressures at the same time is as follows: the adsorption tower after the purge step is completed is connected to the adsorption tower in the equal pressure drop step to achieve pressure increase until the pressures of the two adsorption towers are consistent; wherein, the upper valve of the adsorption tower is first opened to increase the upper pressure, so that the adsorption pressure of the adsorption tower after the purge step is increased by 0.1-0.15MPa; then the lower valve of the adsorption tower is opened to simultaneously increase the upper pressure and the lower pressure, so that the pressures of the two adsorption towers are consistent.

2. The method according to claim 1, wherein The first-stage adsorption tower includes two adsorption towers connected in parallel, and the second-stage adsorption tower includes two or more adsorption towers connected in parallel; The pressure equalization times of the pressure-decreasing step at the upper part of the second-stage adsorption tower are 1 to 5 times, and the pressure equalization times of the pressure-increasing step at the upper part of the second-stage adsorption tower are 1 to 5 times.

3. The method according to claim 2, wherein The second-stage adsorption tower includes 2-4 adsorption towers connected in parallel; the pressure equalization times of the pressure drop step at the upper part of the second-stage adsorption tower is 1 time, and the pressure equalization times of the pressure increase step at the upper part of the second-stage adsorption tower is 1~2 times.

4. The method according to claim 1, wherein If the oxygen content of the argon-rich gas after passing through the oxygen removal system is 100 ppm, the volume content of argon in the high-purity argon gas is 99.99%; if the oxygen content of the argon-rich gas after passing through the oxygen removal system is 50 ppm, the volume content of argon in the high-purity argon gas is 99.995%; if the oxygen content of the argon-rich gas after passing through the oxygen removal system is 10 ppm, the volume content of argon in the high-purity argon gas is 99.999%.

5. The method according to claim 1, wherein The adsorption pressure of the adsorption tower during the adsorption step of the first stage is 0.6-1.0 MPa; the adsorption pressure of the adsorption tower during the adsorption step of the second stage is 0.04-1.0 MPa; the inlet pressure of the third stage catalytic deoxidation device is 0.1-1.0 MPa; After the upper pressure drop step of the first adsorption tower, the adsorption pressure of the adsorption tower is 0.3~0.5MPa; after the upper pressure drop step of the second adsorption tower, the adsorption pressure of the adsorption tower is 0.02~0.5MPa.

6. The method according to claim 1, wherein The oxygen removal system and the carbon dioxide removal system are operated in series; the oxygen removal system includes a third-stage deoxygenation tower, which includes three or more deoxygenation towers connected in series; the carbon dioxide removal system includes a third-stage adsorption tower, which adopts a pressure swing adsorption or temperature swing adsorption method, and the third-stage adsorption tower includes two adsorption towers connected in parallel; The adsorbent filled in the first-stage adsorption tower is 4A molecular sieve or carbon molecular sieve; the adsorbent filled in the second-stage adsorption tower is LiX, NaX or CaX zeolite molecular sieve; the adsorbent filled in the third-stage deoxygenation tower is a transition metal-loaded carbon material, and oxygen reacts with the transition metal-loaded carbon material to generate carbon dioxide.

7. The method according to any one of claims 1 to 6, wherein: If the first-stage adsorption tower is used to remove nitrogen, carbon dioxide, and water first, the type of adsorbent in the first-stage adsorption tower and the second-stage adsorption tower needs to be replaced. At the same time, the steps, number of adsorption towers, and adsorption pressure of each adsorption tower in a cycle need to be converted. The third-stage catalytic deoxygenation device and method remain unchanged. At this time, the first-stage adsorption tower produces an intermediate gas rich in oxygen and argon, with a total volume content of 80-90%; the second-stage adsorption tower produces an argon-rich gas with a volume content of 99-99.9%; the third-stage catalytic deoxidation device produces high-purity argon with a volume content of 99.99-99.999%. The adsorbent filled in the first adsorption tower is LiX, NaX or CaX zeolite molecular sieve; the adsorbent filled in the second adsorption tower is 4A molecular sieve or carbon molecular sieve; Each adsorption tower of the first stage adsorption tower undergoes the steps of adsorption, upper pressure drop, inversion, purging, upper pressure increase, and final increase in sequence within one cycle. Each adsorption tower of the second stage adsorption tower undergoes the steps of adsorption, upper pressure drop, upper and lower pressure drop simultaneously, inversion, purging, upper pressure increase, upper and lower pressure increase simultaneously, and final increase in one cycle. The first adsorption tower includes two or more adsorption towers connected in parallel; the second adsorption tower includes two adsorption towers connected in parallel; the pressure equalization times of the pressure drop step at the top of the first adsorption tower is 1 to 5 times, and the pressure equalization times of the pressure increase step at the top of the first adsorption tower is 1 to 5 times; The adsorption pressure of the adsorption tower during the adsorption step of the first adsorption tower is 0.04~1.0MPa gauge pressure; the adsorption pressure of the adsorption tower during the adsorption step of the second adsorption tower is 0.6~1.0MPa gauge pressure; the adsorption pressure of the adsorption tower after the upper pressure drop step of the first adsorption tower is 0.02~0.5MPa gauge pressure; the adsorption pressure of the adsorption tower after the upper pressure drop step of the second adsorption tower is 0.3~0.5MPa gauge pressure.

8. The method according to claim 7, wherein When the first-stage adsorption tower is used to first remove nitrogen, carbon dioxide and water, if the adsorption pressure of the adsorption tower during the adsorption step of the first-stage adsorption tower is ≤0.04 MPa, a vacuuming step is added before the purge step of the first-stage adsorption tower, and the pressure after vacuuming is -0.06~-0.05 MPa; or / and a compression step is added before the adsorption step of the second-stage adsorption tower, so that the adsorption pressure of the adsorption tower during the adsorption step is 0.6~1.0 MPa.

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