Argon recovery and purification method and device

Abstract

Disclosed in the present invention are an argon recovery and purification device and method. The purification method comprises: filtering out solid particles from crude argon recovered by a workbench; compressing the crude argon and then removing water, carbon monoxide and carbon dioxide; after purification and cooling, removing nitrogen, oxygen and impurities to obtain high-purity argon, and reheating the high-purity argon and feeding same to a production line. The purification device comprises: a recovery vacuum pump, a crude argon filter, a recovery buffer, a recovery compressor, an outer low-temperature adsorber, a cryogenic cold box, a main heat exchanger, and an inner low-temperature adsorber. In the present invention, crude argon is first filtered and compressed to a pressure that is slightly higher than the pressure required by an argon utilization process and then undergoes the two-step adsorption in the outer low-temperature adsorber and the inner low-temperature adsorber in the cryogenic cold box and a catalytic reaction to remove impurities, and then the purified high-purity argon is reheated by means of the main heat exchanger and is fed to the production line. The whole process does not require throttling and decompression processes and the pressure difference between the argon product and the exhaust pressure of the compressor is small, thereby effectively reducing energy consumption and production costs.

Description

Argon recovery and purification method and apparatus Technical Field

[0001] This invention relates to the field of argon recovery and purification technology, and in particular to an argon recovery and purification method and apparatus. Background Technology

[0002] Argon contains approximately 0.93% of the atmosphere, with a boiling point of about -186°C, very close to oxygen's boiling point of -183°C. Trace amounts of oxygen impurities in argon are difficult to separate using distillation, primarily because their boiling points are so close to oxygen, requiring approximately 180 theoretical plates, which is extremely expensive. Currently, the production of monocrystalline silicon and the 3D printing industry consume large quantities of argon. Argon is a rare gas in industrial applications and is difficult to obtain; therefore, the recycling of argon has become a practical necessity. Analysis of emitted argon reveals that the main impurities are oxygen, nitrogen, carbon monoxide, hydrocarbons, and moisture.

[0003] In existing technologies, argon recovery can be divided into single-tower distillation and double-tower distillation, depending on the distillation process. Typically, single-tower distillation achieves an argon recovery rate of 85%-90%, while double-tower distillation systems can reach 96%. However, double-tower distillation systems require liquid argon vaporization to provide cooling to compensate for cooling losses in the cold box. Furthermore, when argon is purified by distillation, a significant pressure difference exists between the argon and the compressor exhaust: because the argon needs to evaporate in the reboiler before entering the distillation column, the pressure difference between the product and the pressure after the feed compressor exceeds 0.3 MPa, resulting in higher energy consumption. Additionally, in double-tower distillation recovery units, the second-stage distillation column operates at a lower pressure, requiring return to the feed compressor for processing, or the addition of additional compression equipment. This makes the pre-treatment equipment for removing carbon monoxide, moisture, and carbon dioxide in double-tower distillation argon recovery units significantly larger than that in single-stage distillation units. Summary of the Invention

[0004] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0005] The purpose of this invention is to address the shortcomings of existing technologies by proposing an argon gas recovery and purification method and apparatus.

[0006] To achieve the above objectives, in a first aspect, the present invention provides an argon gas recovery and purification method, comprising:

[0007] S100, the crude argon gas flow after recovery on the workbench is filtered out of solid particles by the recovery vacuum pump and crude argon filter, and then flows through the recovery buffer and recovery compressor to be compressed to a pressure higher than that required by the argon gas usage process.

[0008] S200, the compressed crude argon gas flows through the adsorbent and catalyst on different adsorption beds of the external cryogenic adsorber to remove moisture, carbon monoxide and carbon dioxide;

[0009] In S300, the crude argon gas stream, after being purified and cooled by the main heat exchanger in the cryogenic cold box, flows through the adsorption bed of the inner cryogenic adsorber to remove nitrogen, oxygen and impurities, resulting in high-purity argon gas. The high-purity argon gas stream is then reheated by the main heat exchanger in the cryogenic cold box before entering the production line.

[0010] In some embodiments, the internal cryogenic adsorber is used interchangeably, and the adsorbent and catalyst on different beds of the external cryogenic adsorber are regenerated and activated by purified air or nitrogen heated by a regeneration electric heater.

[0011] In some embodiments, the cryogenic cold box is cooled by liquid argon in a cryogenic liquid argon storage tank. After the liquid argon in the cryogenic liquid argon storage tank evaporates, it flows through the main heat exchanger for reheating and then flows through the recovery buffer to replenish the argon gas loss.

[0012] In some embodiments, the internal cryogenic adsorber is switched on and the adsorbent on the internal cryogenic adsorber is regenerated by heating with nitrogen, and the nitrogen, oxygen and impurities adsorbed in the adsorbent are desorbed by a regeneration vacuum pump.

[0013] In a second aspect, the present invention also provides an argon gas recovery and purification apparatus for operating the argon gas recovery and purification method as described in the first aspect, the argon gas recovery and purification apparatus comprising:

[0014] A recovery vacuum pump is connected to a workbench via a pipeline;

[0015] A coarse argon filter, which is connected to a recovery vacuum pump via a pipeline;

[0016] A recovery buffer, which is connected to a coarse argon filter via a pipe;

[0017] A recycling compressor, which is connected to a recycling buffer via a pipeline;

[0018] An external low-temperature adsorber, which is connected to a recovery compressor via a pipeline;

[0019] The low-temperature cold box is equipped with a main heat exchanger and an inner low-temperature adsorber. The main heat exchanger is connected to the outer low-temperature adsorber through a pipe, and the inner low-temperature adsorber is connected to the main heat exchanger through a pipe.

[0020] In some embodiments, the cryogenic cold box cavity is connected to a cryogenic liquid argon storage tank via a pipe, and the cryogenic cold box cavity is connected to a recovery buffer via a pipe.

[0021] In some embodiments, the external low-temperature adsorber adsorption bed includes an upper bed, a middle bed, and a lower bed, wherein the upper bed and the lower bed are provided with adsorbent, and the middle bed is provided with a catalyst.

[0022] In some embodiments, the internal cryogenic adsorber includes a first adsorber and a second adsorber, the first adsorber being connected to the external cryogenic adsorber via a pipe, and the second adsorber being connected to the first adsorber and the main heat exchanger via a pipe.

[0023] In some embodiments, the adsorption beds of the first and second adsorbers are provided with molecular sieves of different pore sizes, with the pore size of the adsorbent in the first adsorber being larger than that in the second adsorber.

[0024] In some embodiments, the external cryogenic adsorber is connected to the regenerative electric heater via a pipe, and the cryogenic cold box is connected to the regenerative vacuum pump via a pipe.

[0025] The present invention has the following beneficial effects:

[0026] 1. In this invention, the crude argon gas containing contamination recovered from the workbench is filtered and compressed to a pressure slightly higher than that required for the argon gas usage process. Then, it undergoes two steps of adsorption and catalytic reaction, namely an external low-temperature adsorber and an internal low-temperature adsorber in a low-temperature cold box, to remove impurities. Subsequently, the purified high-purity argon gas is reheated through the main heat exchanger and introduced into the production line, thereby realizing the recycling and reuse of argon gas.

[0027] 2. This invention eliminates the secondary high-temperature catalytic reaction device and the process step of removing nitrogen impurities from crude argon using low-temperature distillation. The entire process does not require throttling or pressure reduction, and the pressure difference between the product argon and the compressor exhaust pressure is small, which effectively improves production safety and reduces energy consumption and production costs. Attached Figure Description

[0028] Figure 1 is a flowchart of the argon gas recovery and purification method proposed in this invention;

[0029] Figure 2 is a schematic diagram of the argon gas recovery and purification device proposed in this invention.

[0030] Legend: 1. Workbench; 2. Recovery vacuum pump; 3. Coarse argon filter; 4. Recovery buffer; 5. Recovery compressor; 6. External cryogenic adsorber; 7. Cryogenic cold box; 8. Main heat exchanger; 9. Internal cryogenic adsorber; 91. First adsorber; 92. Second adsorber; 10. Regeneration electric heater; 11. Regeneration vacuum pump; 12. Cryogenic liquid argon storage tank; 13. Piping; 14. Control valve; 101, 102, 103. Recovered crude argon; 104, 105. Compressed crude argon; 106, 107A, 107B. Crude argon after removal of moisture, carbon dioxide, and carbon monoxide; 108A, 108B. Cooled cryogenic crude argon; 109A, 1 09B, Low-temperature crude argon gas after nitrogen removal; 110A, 110B, High-purity argon gas after oxygen removal; 111A, 111B, High-purity argon gas reheated to room temperature; 112, High-purity argon gas entering the production line; 201, Purified air used for carbon monoxide activation and regeneration; 204, Vented regeneration gas; 301, Nitrogen gas used for regeneration; 303A, 303B, Nitrogen gas used for heating the low-temperature cold box; 304A, 304B, Nitrogen gas used for heating the internal low-temperature adsorber; 305A, 305B, Impure gas extracted by the regeneration vacuum pump; 401, 402A, 402B, Replenished liquid argon; 403A, 403B, 404, Replenished lost liquid argon. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] Currently, the argon content in Earth's atmosphere is approximately 0.93%, with a boiling point of about -186°C, very close to that of oxygen (-183°C). This makes it difficult to separate trace oxygen impurities in argon using distillation, primarily because the boiling point is so close to oxygen, requiring approximately 180 theoretical plates, and the equipment and separation costs are prohibitively high. Currently, the monocrystalline silicon and 3D printing industries consume large quantities of argon, which is a rare gas in industrial applications and is expensive to obtain. Therefore, argon recycling has become a practical necessity. Analysis of emitted argon reveals that its main impurities are oxygen, nitrogen, carbon monoxide, hydrocarbons, moisture, and trace amounts of liquid lubricating oil mist. Using a dry screw or Roots vacuum pump for evacuation can largely eliminate this oil mist, thus recycling this portion of argon can effectively reduce production costs.

[0033] In existing technologies, common methods for argon gas recovery and purification are as follows: First, argon gas recovered from a 3D printer or single crystal furnace is filtered to remove particulate matter, and then compressed and cooled by an oil-free compressor. Next, it enters a high-temperature catalytic reaction stage, where carbon monoxide and oxygen react to produce water and carbon dioxide, and an excess of oxygen is required during the catalytic reaction. The cooled crude argon enters a second-stage catalytic reactor where, under the action of a catalyst, excess oxygen reacts with added hydrogen to produce water, and an excess of hydrogen is required during the catalytic reaction. The impurities in the oxygen-free argon gas are water, carbon dioxide, hydrogen, and nitrogen. The oxygen-free crude argon gas is cooled to below 15°C and enters a molecular sieve adsorber to remove water and carbon dioxide. The purified crude argon gas enters a cold box, is cooled in the main heat exchanger, and then distilled in a distillation column, where hydrogen and nitrogen are separated to obtain argon gas.

[0034] Depending on the distillation process, argon distillation is classified into single-tower distillation and double-tower distillation. Argon distillation columns typically require supplemental liquid argon to provide some cooling, allowing the argon extraction rate of single-tower distillation to reach approximately 85%-90%. Double-tower distillation, on the other hand, can achieve an argon recovery rate of up to 96% (requiring 4% liquid argon to compensate for cooling losses in the cold box). However, when using distillation to remove nitrogen from the argon recovery unit, the argon before entering the distillation column needs to be evaporated in the reboiler. Therefore, the pressure difference between the product pressure and the pressure after the feed compressor will be greater than 0.3 MPa. This large pressure difference between the product argon and the compressor exhaust pressure results in high energy consumption for the entire unit. When the pressure of the second-stage distillation column in a double-tower distillation argon recovery unit is low, it needs to be returned to the feed compressor for processing or additional compression equipment needs to be added. Therefore, the pre-treatment equipment of the recovery unit is more complex and larger than that of a single-stage distillation unit.

[0035] This application provides an argon gas recovery and purification device and method, solving the problems of high energy consumption and complex and large pre-removal equipment in existing technologies. In this application, the crude argon gas recovered from the workbench is filtered and compressed to a pressure slightly higher than the pressure required for the argon gas usage process. Then, impurities are removed through a two-step adsorption and catalytic reaction process using an external cryogenic adsorber and an internal cryogenic adsorber in a cryogenic cold box. Subsequently, the purified high-purity argon gas is reheated through the main heat exchanger and introduced into the production line. The entire process requires no throttling or pressure reduction, and the pressure difference between the product argon gas and the compressor exhaust pressure is small, effectively reducing energy consumption and production costs.

[0036] Please refer to the following examples for details:

[0037] Referring to Figure 1, an embodiment of an argon gas recovery and purification method provided by the present invention includes the following specific steps:

[0038] S100, the crude argon gas recovered from the workbench 1 is filtered out of solid particles by the recovery vacuum pump 2 and the crude argon filter 3, and then flows through the recovery buffer 4 and the recovery compressor 5 to be compressed to a pressure higher than that required for the argon gas usage process.

[0039] S200, the compressed crude argon gas flows through the external cryogenic adsorber 6 and the adsorbent and catalyst on different adsorption beds to remove moisture, carbon monoxide and carbon dioxide;

[0040] S300, the crude argon gas stream after removing moisture, carbon monoxide and carbon dioxide is purified and cooled by the main heat exchanger 8 in the low-temperature cold box 7 and then flows through the adsorption bed of the inner low-temperature adsorber 9 to remove nitrogen, oxygen and impurities to obtain high-purity argon gas. The high-purity argon gas stream is reheated by the main heat exchanger 8 in the low-temperature cold box 7 and enters the production line.

[0041] It should be explained in detail that multiple sets of internal low-temperature adsorbers 9 are symmetrically arranged and can be switched for use. Furthermore, the adsorbent and catalyst on different beds of the external low-temperature adsorber 6 undergo catalyst regeneration and adsorbent regeneration activation via purified air or nitrogen heated by the regeneration electric heater 10. During this process, the catalyst is heated to an appropriate temperature to restore its catalytic activity; simultaneously, adsorbed substances (such as nitrogen, oxygen, and other impurities) in the adsorbent are released and effectively removed, ensuring that the adsorption performance of the adsorbent is restored.

[0042] Furthermore, the cryogenic cold box 7 uses the liquid argon cooling chamber in the cryogenic liquid argon storage tank 12. After the liquid argon in the cryogenic liquid argon storage tank 12 evaporates, it flows through the main heat exchanger 8 for reheating and then flows through the recovery buffer 4 to replenish the argon loss in the recovery and purification system.

[0043] Furthermore, multiple sets of internal low-temperature adsorbers 9 are symmetrically arranged and can be switched for use. The adsorbent on the internal low-temperature adsorber 9 is regenerated by heating with nitrogen, and the nitrogen, oxygen and impurities adsorbed in the adsorbent are desorbed by the regeneration vacuum pump 11.

[0044] Referring to Figure 2, the present invention also provides an embodiment of an argon gas recovery and purification device, which is used to operate the argon gas recovery and purification method as described in the above embodiment. The argon gas recovery and purification device includes: a recovery vacuum pump 2, a coarse argon filter 3, a recovery buffer 4, a recovery compressor 5, an external cryogenic adsorber 6, a cryogenic cold box 7, a main heat exchanger 8, an internal cryogenic adsorber 9, a cryogenic liquid argon storage tank 12, a regeneration electric heater 10, and a regeneration vacuum pump 11, which are connected by a pipeline 13 and whose opening and closing and flow path are controlled by a control valve 14 on the pipeline 13.

[0045] The recovery vacuum pump 2 is connected to the workbench 1 via pipe 13, while the coarse argon filter 3 is connected to the recovery vacuum pump 2 via pipe 13, the recovery buffer 4 is connected to the coarse argon filter 3 via pipe 13, and the recovery compressor 5 is connected to the recovery buffer 4 via pipe 13. The contaminated coarse argon gas recovered by the workbench 1 (3D printer or single crystal silicon crystal pulling furnace) will flow through the recovery vacuum pump 2 and the coarse argon filter 3 in sequence to filter out the solid particles, and then flow through the recovery buffer 4 and the recovery compressor 5 to compress it to a pressure higher than that required by the argon gas usage process.

[0046] Furthermore, the external low-temperature adsorber 6 is connected to the recovery compressor 5 through pipe 13. The low-temperature cold box 7 is equipped with a main heat exchanger 8, and an internal low-temperature adsorber 9 is installed below the main heat exchanger 8. The main heat exchanger 8 is connected to the external low-temperature adsorber 6 through pipe 13, and the internal low-temperature adsorber 9 is connected to the main heat exchanger 8 through pipe 13.

[0047] The compressed crude argon gas flows sequentially through the outer cryogenic adsorber 6, the main heat exchanger 8, and the inner cryogenic adsorber 9. The adsorbents and catalysts on different adsorption beds in the outer cryogenic adsorber 6 can remove moisture, carbon monoxide, and carbon dioxide in stages. The crude argon gas, after removing moisture, carbon monoxide, and carbon dioxide, flows through the main heat exchanger 8 in the cryogenic cold box 7 for purification and cooling, and then flows through the adsorption bed of the inner cryogenic adsorber 9 to remove nitrogen, oxygen, and other trace impurities to obtain high-purity argon gas. The high-purity argon gas, after being recovered and purified, flows through the main heat exchanger 8 in the cryogenic cold box 7 again for reheating before finally entering the production line.

[0048] Furthermore, the cryogenic cold box 7 cavity is connected to the cryogenic liquid argon storage tank 12 through pipe 13, the cryogenic cold box 7 cavity is connected to the recovery buffer 4 through pipe 13, the external cryogenic adsorber 6 is connected to the regeneration electric heater 10 through pipe 13, and the cryogenic cold box 7 is connected to the regeneration vacuum pump 11 through pipe 13.

[0049] The cryogenic cold box 7 replenishes fresh liquid argon from the cryogenic liquid argon storage tank 12 to cool the internal cavity, ensuring that the cryogenic adsorber inside the cavity is in a low-temperature environment. After the liquid argon in the cryogenic liquid argon storage tank 12 evaporates, it flows through the main heat exchanger 8 for reheating and then flows through the recovery buffer 4, where it merges with the gas flowing out from the coarse argon filter 3, thereby replenishing the argon gas lost during the recovery process.

[0050] Once the external cryogenic adsorber 6 is saturated, it will be switched to another unit. When regeneration is required, the external cryogenic adsorber 6 will be heated by the regeneration electric heater 10 using regeneration nitrogen or purified compressed air. Excess oxygen in the air during the regeneration process of the external cryogenic adsorber 6 will oxidize the consumed carbon monoxide removal catalyst into metal oxides at high temperatures, which will be used in the next removal process. Then, nitrogen gas is introduced again to evaporate the moisture and carbon dioxide adsorbed in the adsorbent, which are carried away by the regeneration gas. The adsorbent is then cooled to room temperature for later use. Alternatively, the purified compressed air introduced can be nitrogen mixed with some oxygen or oxygen directly heated to activate and regenerate the catalyst.

[0051] Once the internal cryogenic adsorber 9 is saturated, it will switch to another adsorption process. When the internal cryogenic adsorber 9 needs regeneration, it will stop replenishing fresh liquid argon and release the internal cryogenic argon gas through the control valve 14. Then, the adsorbent will be reheated with room temperature nitrogen gas, and the shell of the cryogenic cold box 7 will be reheated to room temperature with room temperature nitrogen gas. Then, it will be regenerated by circulating regenerating nitrogen gas. After the cryogenic adsorber and cryogenic cold box 7 are reheated, the supply of regenerating nitrogen gas will be stopped. The adsorbent will be evacuated by the regeneration vacuum pump 11 to remove residual oxygen and nitrogen gas from the adsorbent. Then, purified high-purity argon gas will be introduced to replace and pressurize the adsorbent for later use.

[0052] It should be explained in detail that the external low-temperature adsorber 6 adsorption bed includes an upper bed, a middle bed, and a lower bed. The upper and lower beds are filled with adsorbent, while the middle bed is filled with a catalyst. The compressed crude argon gas first enters the lower bed, where the adsorbent initially removes moisture before entering the middle bed. Subsequently, under the action of carbon monoxide catalyst, it reacts with the catalyst to generate carbon dioxide, which then enters the upper bed. The adsorbent there further removes moisture and carbon dioxide, resulting in purified crude argon gas.

[0053] Furthermore, the internal cryogenic adsorber 9 includes a first adsorber 91 and a second adsorber 92. The first adsorber 91 is connected to the external cryogenic adsorber 6 via a pipe 13, while the second adsorber 92 is connected to the first adsorber 91 and the main heat exchanger 8 via a pipe 13. The adsorption beds of the first adsorber 91 and the second adsorber 92 are equipped with molecular sieves of different pore sizes, with the adsorbent pore size in the first adsorber 91 being larger than that in the second adsorber 92. Combining molecular sieves of different pore sizes allows for the effective removal of nitrogen and oxygen from crude argon gas at cryogenic temperatures.

[0054] For example, the polluted crude argon gas is filtered and compressed before entering the external low-temperature adsorber 6. In the lower bed A, the adsorbent is used to initially remove moisture. In the middle bed B, copper oxide or manganese oxide catalysts are used to react with carbon monoxide to generate carbon dioxide, thereby achieving the purpose of removing carbon monoxide. Then, it enters the upper bed C where the adsorbent is used to further remove moisture and carbon dioxide.

[0055] Specifically, the CO removal process is as follows: CuO+CO→Cu+CO2, Cu2O+CO→2Cu+CO2; the catalyst regeneration process is as follows: 2Cu+O2→2Cu2O2, Cu2O+O2→4CuO.

[0056] It should be explained in detail that 5A molecular sieves can remove nitrogen and oxygen from crude argon at low temperatures. The adsorption capacity for nitrogen is much greater than that for oxygen. This is because 5A molecular sieves have a greater affinity for nitrogen, and during the adsorption process, nitrogen molecules can also drive out the oxygen molecules that are initially adsorbed. Therefore, 5A molecular sieves cannot completely purify crude argon. 4A molecular sieves have the greatest adsorption capacity for oxygen in crude argon at low temperatures (-183℃), so they are the most effective at purifying oxygen in the mixture. If a certain amount of nitrogen is present in the crude argon, 4A molecular sieves cannot remove either nitrogen or oxygen from the crude argon. Therefore, the lower the nitrogen content in the mixture, the better.

[0057] Therefore, when 5A molecular sieve and 4A molecular sieve are combined, nitrogen and oxygen in crude argon can be effectively removed at low temperature. After removing moisture, carbon monoxide and carbon dioxide, the crude argon enters the low-temperature cold box 7. After being cooled by the purified argon in the main heat exchanger 8, it enters the first adsorber 91 filled with 5A molecular sieve to adsorb and remove nitrogen from the crude argon. Then it enters the second adsorber 92 filled with 4A molecular sieve to adsorb and remove oxygen from the crude argon to obtain high-purity argon. The inner low-temperature adsorber 9 maintains the cooling capacity at -150℃ to -180℃ by replenishing fresh liquid argon. At the same time, the inner low-temperature adsorber 9 and the main heat exchanger 8 are located in the low-temperature cold box 7, and the thermal insulation and cold preservation conditions of the low-temperature cold box 7 reduce the heat transfer from the environment to the inner low-temperature adsorber 9.

[0058] Working principle:

[0059] (1) Remove contaminated crude argon gas (gas volume flow rate of 1000 Nm³) from the 3D printing workbench 1 or the single crystal silicon pulling furnace. 3 Argon gas with a purity greater than 99% and impurities less than 1% (including carbon monoxide less than 2000 ppm, oxygen less than 100 ppm, nitrogen less than 100 ppm, and carbon dioxide less than 10 ppm, etc.) is collected by recovery vacuum pump 2 (section 101 of pipeline). Solid particles are then filtered out in coarse argon filter 3, and the gas then enters recovery buffer 4 (external moisture may increase into the coarse argon gas as it flows through recovery vacuum pump 2, filter, and buffer). Finally, it is mixed with argon gas returned from cryogenic chamber 7 (section 102 of pipeline, gas volumetric flow rate of 30 Nm³). 3The gas flows through the confluence of pipes ( / h) and is then compressed by the recovery compressor 5 (pipeline section 103, gas pressure 0.7MPa, gas volumetric flow rate 1030Nm³). 3 The gas is cooled (to below 40°C in section 104 of the pipeline) and then enters the lower bed A of the external cryogenic adsorber 6. After initial removal of moisture, the adsorbent enters the middle bed B, where it reacts with the catalyst under the action of carbon monoxide to generate carbon dioxide. The carbon monoxide then enters the upper bed C, where the adsorbent further removes moisture and carbon dioxide, resulting in purified crude argon gas (section 106 of the pipeline, with an average gas volumetric flow rate of 1020 Nm³). 3 / h, approximately 10Nm 3 / h represents the regeneration loss of the internal cryogenic adsorber 9; the pressure is 0.68 MPa, and the impurities in the argon gas include less than 1 ppm of carbon monoxide, less than 1 ppm of carbon dioxide, less than 1 ppm of moisture, and about 100 ppm of nitrogen.

[0060] (2) The crude argon gas, after being detoxified of carbon monoxide, moisture, and carbon dioxide, enters the main heat exchanger 8 (sections 107A and 107B) inside the cryogenic cold box 7. The purified argon gas is cooled to -161℃ and then enters the inner cryogenic adsorber 9 (sections 108A, 108B, 109A, and 109B; the first adsorber 91 removes nitrogen impurities from the crude argon, and the second adsorber 92 removes oxygen and other trace hydrocarbon impurities). High-purity argon gas is then obtained (sections 110A and 110B, average gas flow rate 1000 Nm³). 3 / h, approximately 10Nm 3 / h represents the regeneration loss of the internal cryogenic adsorber 9). The high-purity argon gas is then reheated to room temperature through the main heat exchanger 8 and flows out of the cryogenic cold box 7 (pipes 111A, 111B), and is output as a product to the production line (pipe 112, average gas flow rate 1000Nm). 3 / h, pressure 0.62MPa, argon purity greater than 99.999%, impurities include less than 1ppm carbon monoxide, less than 1ppm carbon dioxide, less than 1ppm water, less than 1ppm nitrogen and less than 1ppm oxygen).

[0061] (3) After the liquid argon in the cryogenic liquid argon storage tank 12 enters the cooling chamber of the cryogenic cold box 7 (pipeline sections 401, 402A, and 402B, with an average gas flow rate of 30 Nm³), 3 / h, pressure 0.7MPa), liquid argon will evaporate and absorb heat in the cavity to maintain the low temperature environment inside the cavity (the internal low temperature adsorber 9 is also equipped with a temperature instrument, which is not shown in the figure as it is existing technology. During the adsorption stage, the adsorber is kept below -160℃ by adjusting the liquid argon supply). After the liquid argon evaporates, it is reheated to the ambient temperature by the main heat exchanger 8 and then enters the recovery buffer 4 (section 404 of the pipeline). It is compressed by the recovery compressor 5 to replenish the argon lost during the recovery process.

[0062] (4) After the external low-temperature adsorber 6 becomes saturated, it needs to be regenerated. The external low-temperature adsorber 6 is heated by the regeneration electric heater 10 (sections 201 and 301 of the pipeline, heated to above 100°C) using nitrogen or purified compressed air for regeneration. During the regeneration process of the external low-temperature adsorber 6, the excess oxygen in the air will oxidize the consumed catalyst into metal oxides at high temperature for use in the next removal process (100-200°C). Then, nitrogen is introduced to evaporate the moisture and carbon dioxide adsorbed in the adsorbent and carry them out with the regeneration gas. The adsorbent is then cooled to room temperature for later use (section 204 of the pipeline). The purified compressed air introduced can also be nitrogen mixed with some oxygen or oxygen directly heated to activate and regenerate the catalyst.

[0063] (5) After the internal low-temperature adsorber 9 is saturated, it will be switched to use. The internal low-temperature adsorber 9 that needs to be regenerated will stop replenishing fresh liquid argon and release the internal low-temperature argon through the control valve 14. Then, the adsorbent will be reheated with room temperature nitrogen (pipes 301, 303A, 303B). At the same time, the shell of the low-temperature cold box 7 will be reheated to room temperature with room temperature nitrogen (pipes 304A, 304B). Then, it will be regenerated by regenerating nitrogen. After the low-temperature adsorber and the low-temperature cold box 7 are reheated, the supply of regenerating nitrogen will be stopped. The adsorbent will be evacuated by the regeneration vacuum pump 11 (pipes 305A, 305B) to remove the residual oxygen and nitrogen in the adsorbent. Then, purified high-purity argon will be introduced to replace and pressurize it for use.

[0064] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for argon gas recovery and purification, characterized in that, include: S100, the crude argon gas after recovery from the workbench (1) is filtered out of solid particles by the recovery vacuum pump (2) and the crude argon filter (3), and then flows through the recovery buffer (4) and the recovery compressor (5) to be compressed to a pressure higher than that required for the argon gas usage process; S200, the compressed crude argon gas flows through the external low-temperature adsorber (6) and the adsorbents and catalysts on different adsorption beds remove moisture, carbon monoxide and carbon dioxide; S300, the crude argon gas, after being dehydrated, decomposed, and decomposed, is purified and cooled by the main heat exchanger (8) in the low-temperature cold box (7) and then flows through the adsorption bed of the inner low-temperature adsorber (9) to remove nitrogen, oxygen and impurities to obtain high-purity argon gas. The high-purity argon gas is then reheated by the main heat exchanger (8) in the low-temperature cold box (7) and enters the production line.

2. The argon recovery and purification method according to claim 1, characterized in that, The inner low-temperature adsorber (9) is switched for use, and the adsorbents and catalysts on different beds of the outer low-temperature adsorber (6) are regenerated and activated by purified air or nitrogen heated by the regeneration electric heater (10).

3. The argon recovery and purification method according to claim 1, characterized in that, The cryogenic cold box (7) is cooled by liquid argon in the cryogenic liquid argon storage tank (12). After the liquid argon in the cryogenic liquid argon storage tank (12) evaporates, it flows through the main heat exchanger (8) for reheating and then flows through the recovery buffer (4) to replenish the argon gas loss.

4. The argon recovery and purification method according to claim 1, characterized in that, The internal low-temperature adsorber (9) is switched to use. The adsorbent on the internal low-temperature adsorber (9) is regenerated by heating with nitrogen, and the nitrogen, oxygen and impurities adsorbed in the adsorbent are desorbed by the regeneration vacuum pump (11).

5. An argon gas recovery and purification device, characterized in that, The purification apparatus is used to operate the argon gas recovery and purification method as described in any one of claims 1 to 4, wherein the argon gas recovery and purification apparatus comprises: A recovery vacuum pump (2) is connected to a workbench (1) via a pipe (13); A coarse argon filter (3) is connected to a recovery vacuum pump (2) via a pipe (13); A recovery buffer (4) is connected to a coarse argon filter (3) via a pipe (13); A recycling compressor (5) is connected to a recycling buffer (4) via a pipe (13); An external low-temperature adsorber (6) is connected to a recovery compressor (5) via a pipe (13); The low-temperature cold box (7) is equipped with a main heat exchanger (8) and an inner low-temperature adsorber (9). The main heat exchanger (8) is connected to the outer low-temperature adsorber (6) through a pipe (13), and the inner low-temperature adsorber (9) is connected to the main heat exchanger (8) through a pipe (13).

6. The argon recovery and purification apparatus according to claim 5, characterized in that, The low-temperature cold box (7) cavity is connected to the low-temperature liquid argon storage tank (12) through a pipe (13), and the low-temperature cold box (7) cavity is connected to the recovery buffer (4) through a pipe (13).

7. The argon recovery and purification apparatus according to claim 5, characterized in that, The external low-temperature adsorber (6) includes an upper bed, a middle bed and a lower bed. The upper bed and the lower bed are provided with adsorbents, and the middle bed is provided with a catalyst.

8. The argon recovery and purification apparatus according to claim 5, characterized in that, The internal low-temperature adsorber (9) includes a first adsorber (91) and a second adsorber (92). The first adsorber (91) is connected to the external low-temperature adsorber (6) through a pipe (13), and the second adsorber (92) is connected to the first adsorber (91) and the main heat exchanger (8) through a pipe (13).

9. The argon recovery and purification apparatus according to claim 8, characterized in that, The adsorption beds of the first adsorber (91) and the second adsorber (92) are provided with molecular sieves of different pore sizes, and the pore size of the adsorbent in the first adsorber (91) is larger than that of the adsorbent in the second adsorber (92).

10. The argon recovery and purification apparatus according to claim 5, characterized in that, The external low-temperature adsorber (6) is connected to the regenerative electric heater (10) through a pipe (13), and the low-temperature cold box (7) is connected to the regenerative vacuum pump (11) through a pipe (13).

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