Method for regenerating a pre-purification container

Abstract

A system and method for regenerating a pre-purified container are provided, particularly suitable for pre-purifying a feed air stream in a cryogenic air separator that uses an oxygen-enriched purge gas stream to regenerate the pre-purification unit. The disclosed pre-purification system and method are configured to substantially remove all water, carbon dioxide, and other impurities from the feed air stream, optionally including hydrogen and carbon monoxide impurities. The method for regenerating the pre-purified container preferably includes regenerating the container with an oxygen-enriched purge gas after depressurization, then partially repressurizing the container with an auxiliary purge gas to dilute the oxygen concentration of the gas contained in the pre-purified container, and optionally depressurizing the partially repressurized container.

Description

Technical Field

[0001] The present invention relates to systems and methods for regenerating pre-purified containers, and more specifically, to methods and systems for regenerating pre-purified containers of air separation devices, wherein the regeneration purge gas is an oxygen-enriched purge gas. Background Technology

[0002] Adsorption is a recognized technique for purifying gases and treating fluid waste streams. Atmospheric air purification and separation constitute one of the main areas where adsorption methods are widely used. To improve its efficiency, new and improved pre-purification systems and methods are constantly being developed.

[0003] One area of ​​strong commercial and technological interest represents the pre-purification of air prior to its cryogenic distillation. Conventional air separation units for the production of nitrogen (N2), oxygen (O2), and argon (Ar) via cryogenic air separation typically consist of two or at least three integrated distillation columns operating at very low temperatures. Due to these low temperatures, water vapor (H2O) and carbon dioxide (CO2) must be removed from the compressed air fed into the air separation unit. Without removal, the water and carbon dioxide present in the feed air will freeze and clog the heat exchangers used to cool the feed air before distillation in the cryogenic distillation columns. Preferably, to avoid freezing, the water content in the compressed and pre-purified air feed stream must be less than 0.1 ppm (parts per million), while the carbon dioxide content must be less than 1.0 ppm. Removal of hydrocarbons and nitrous oxide is also typically required to ensure the safe operation of such cryogenic distillation systems, which often involve handling oxygen-enriched streams.

[0004] Currently, commercial methods for prepurifying feed air include temperature-swing adsorption units, which employ layers of adsorbent material along with optional catalytic prepurification techniques. Prepurification units are typically used upstream of cryogenic distillation systems, comprising a leading adsorbent layer to remove water, carbon dioxide, and hydrocarbons and other contaminants, including nitrogen oxides. Such prepurification units may also optionally include one or more catalysts for removing one or more contaminants, followed by a final adsorbent layer downstream of the optional catalyst for removing contaminants generated by the catalytic process. For example, some cryogenic air separation applications in the electronics industry and other selected industries require the removal of hydrogen and / or carbon monoxide from the feed air stream before it can be processed in cryogenic distillation systems to produce high-purity or ultra-high-purity nitrogen products.

[0005] Thermal regeneration processes used in such temperature-switched adsorption pre-purification units associated with air separation devices are employed to desorb water, carbon dioxide, and selected other contaminants, such as hydrocarbons and nitrous oxide, from the various layers within the pre-purifier unit. Conventional thermal regeneration is preferably performed using a multi-step process involving at least four general steps: (i) depressurizing the pre-purification vessel to a lower pressure suitable for the regeneration process; (ii) heating the layers within the pre-purification vessel with a heated purge gas to desorb water, carbon dioxide, and other contaminants from the individual adsorption layers and to clean the catalyst layer; (iii) cooling the layers within the pre-purification vessel to a temperature suitable for the pre-purification process with a cooler purge gas (often referred to as a cold purge gas); and (iv) repressurizing the pre-purification vessel back to the higher operating pressure required for the pre-purification process. During conventional thermal regeneration of the pre-purification vessel, the hot and cold purge gases typically consist of an air stream or a waste nitrogen-enriched air stream. However, oxygen-enriched streams have also been previously used as both hot and cold purge gases, but special safety considerations are required.

[0006] The safe operation of air separation units is crucial. Therefore, when using oxygen-enriched purge gas to regenerate the pre-purifier unit associated with the air separation unit, special cleaning treatments or the use of special materials may be required for some pipes, containers, valves, and other equipment to ensure safe operation if such components come into contact with a high-oxygen-concentration gas flow. Thus, it is desirable to minimize special cleaning / treatment and special material requirements (and associated costs) by ensuring that the oxygen content of the gas remaining in the pre-purifier container is diluted after regeneration, thereby ensuring that no oxygen-enriched airflow clogs the air separation unit's cold box or the turbine machinery upstream of the cold box when the pre-purification container is circulated to the purification step. Therefore, there is a ongoing need to improve the regeneration of pre-purification units using oxygen-enriched purge gas to ensure that the oxygen concentration of the gas in the repressurized pre-purification container is less than or equal to about 30% molar volume, and more preferably less than or equal to about 26% molar volume, to ensure the safe operation of the air separation unit and reduce the capital and operating costs associated with meeting the special design and treatment requirements of components in contact with oxygen-enriched gas. Summary of the Invention

[0007] The general feature of this invention is that, as a method for regenerating a pre-purification container, it includes the following steps: (i) depressurizing the pre-purification container to a regeneration pressure, the pre-purification container having one or more layers of adsorbent and / or catalyst disposed therein; (ii) heating the one or more layers of adsorbent material and / or one or more layers of catalyst material disposed in the pre-purification container with a hot oxygen-enriched purge gas to desorb water and carbon dioxide from the one or more layers; (iii) cooling the one or more layers of adsorbent and / or catalyst layer in the pre-purification container with a cold oxygen-enriched purge gas; (iv) partially repressurizing the pre-purification container to an intermediate pressure with an auxiliary purge gas to dilute the oxygen concentration of the gas contained in the pre-purification container; and (v) completely repressurizing the pre-purification container to the working pressure for pre-purifying the feed gas, wherein the oxygen concentration of the gas in the repressurized pre-purification container is less than or equal to about 30% molar volume, and more preferably, the oxygen concentration is less than about 26% molar volume.

[0008] In some embodiments, the step of repressurizing the pre-purification container portion further includes repressurizing the pre-purification container portion using an auxiliary purge gas, then depressurizing the pre-purification container and releasing the auxiliary purge gas and any oxygen-enriched purge gas remaining in the pre-purification container. In other embodiments, the step of repressurizing the pre-purification container portion further includes repressurizing the pre-purification container portion using a nitrogen-enriched gas with a nitrogen concentration of about 85% molar volume to dilute the oxygen concentration of the gas remaining in the pre-purification container. One or more adsorbent layers within the pre-purification container preferably comprise activated alumina, silica gel, zeolite-based molecular sieves, X-type zeolite, or combinations thereof, while one or more layers within the pre-purification container comprise a hogallat catalyst or a noble metal catalyst, such as an alumina-supported palladium catalyst. The regeneration pressure is preferably less than about 6.0 bar, more preferably between about 1.0 bar and 2.0 bar, while the operating pressure is typically greater than or equal to about 6.0 bar.

[0009] Preferably, a heater is used to heat the hot oxygen-enriched purge gas to a temperature of at least 150°C, while the cold oxygen-enriched purge gas is at a temperature of less than or equal to about 50°C. Both are preferably derived from the oxygen-enriched stream of the condenser of the distillation column system or the air separator. The auxiliary purge gas is preferably air, such as a dry air stream taken downstream of the pre-purifier unit, a branch of the feed air taken upstream of the pre-purifier unit, or even the synthesis air stream taken from the air separator. Alternatively, the auxiliary purge gas may be a nitrogen-enriched gas taken from the air separator or a nearby nitrogen storage tank. Attached Figure Description

[0010] Although the conclusions of this specification are those of one or more claims that the applicant considers to be the subject of the invention and explicitly points to the inventive subject matter, it is believed that the inventive system and method for pre-purification of feed gas streams will be better understood when considered in conjunction with the accompanying drawings, wherein:

[0011] Figure 1 This is a schematic diagram of a pre-purification container associated with an air separation unit, showing a pre-purification container having one or more adsorbent layers and / or catalyst layers; and

[0012] Figure 2 This is a schematic diagram of a dual-bed pre-purification apparatus configured for use in conjunction with the method of the regeneration pre-purification container of the present invention, and shows the various flow loops and valves within the pre-purification apparatus. Detailed Implementation

[0013] The system and method for regenerating pre-purification containers of the present invention are intended for applications such as pre-purification devices associated with cryogenic air separation devices, preferably using an oxygen-enriched purge gas stream for regeneration.

[0014] Now go to Figure 1 This illustration shows one embodiment of a pre-purification bed 20 suitable for use in conjunction with the systems and methods of the present invention for pre-purifying feed gas streams, such as air. When associated with an air separation unit, the systems and methods of the present invention for pre-purifying feed gas streams preferably comprise at least two pre-purification beds configured to purify a feed air stream received at an inlet 22 of a cylindrical container 21 containing multiple adsorption layers and / or catalyst layers, and to deliver a purified air stream at an outlet 23. Each of the at least two pre-purification containers is also configured to regenerate the adsorption layers and catalyst layers contained within the pre-purification container using one or more oxygen-enriched purge gas streams. As is well known in the art, the use of two or more pre-purification containers in cryogenic air separation units enables the continuous production of purified air, which is subsequently separated in a distillation column within the cold chamber of the air separation unit. When one or more of the pre-purification containers are being used to purify incoming feed air, a process widely known as thermal regeneration is preferably used to regenerate one or more of the other pre-purification containers. Each pre-purification container comprises multiple layers, including one or more layers of adsorbent material, such as activated alumina and / or zeolite-based molecular sieves, and one or more layers of catalyst-containing material, such as hogallat catalysts and / or noble metal catalysts.

[0015] Figure 1The pre-purification bed 20 shown comprises a first layer of alumina 24 and a second layer of zeolite-based molecular sieve 25 disposed within a cylindrical container 21, both configured to purify the feed gas stream by adsorbing impurities such as water vapor, carbon dioxide, and nitrous oxide. Downstream of layers 24 and 25 is a third layer 26 containing hogallats, i.e., catalyst materials, which oxidize carbon monoxide to carbon dioxide and also adsorb hydrogen and / or convert hydrogen to water. Downstream of the hogallats-containing layer 26 is an optional zeolite-based molecular sieve (not shown) configured to remove water and carbon dioxide from the gas stream exiting the hogallats-containing layer and optionally a layer containing a noble metal catalyst, such as an alumina-supported palladium catalyst (e.g., 0.5 wt% Pd / Al₂O₃), which is configured to oxidize most of the remaining hydrogen to water. The final capping layer 28 of the zeolite-based molecular sieve is also shown, which is configured to adsorb water vapor and carbon dioxide generated in the layer containing catalyst material. Multiple separation screens 27, such as Monel separation screens, can also be installed between each catalyst layer 26 and any adjacent layers 25 and 28.

[0016] The system and method of the present invention are a modification or improvement to a conventional process for thermally regenerating a pre-purification vessel in a cryogenic air separation unit, and are particularly suitable for pre-purifier applications using oxygen-enriched purge gas to regenerate the pre-purifier unit. The method of the present invention adds one or more additional steps to a conventional thermal regeneration process, and the generalized feature of the method of the present invention is the following steps: (i) depressurizing the pre-purification container to a lower pressure suitable for the regeneration of the pre-purifier; (ii) heating the adsorbent layer and catalyst layer in the pre-purification container with heated oxygen-enriched purge gas to desorb water and carbon dioxide from each layer and regenerate the catalyst layer; (iii) cooling the adsorbent layer and catalyst layer in the pre-purification container to a temperature suitable for the pre-purification process with cold oxygen-enriched purge gas; (iv) after the cooling step, partially repressurizing the pre-purification container with auxiliary purge gas to dilute the oxygen concentration of the gas remaining in the pre-purification container, and optionally depressurizing the partially repressurized container; (v) fully repressurizing the pre-purification container back to the higher operating pressure required for the pre-purification process, wherein the oxygen concentration of the gas in the fully repressurized pre-purification container is less than or equal to about 30% molar volume, and more preferably, less than or equal to about 26% molar volume.

[0017] Specifically, in a preferred embodiment, step (iv) of the above process further includes: (a) repressurizing the pre-purification container portion to a predetermined intermediate pressure using an auxiliary purge gas with an oxygen concentration of less than about 23%, preferably using a clean, dry air stream taken from a downstream location of the pre-purifier device, or optionally using a branch of the feed air stream taken from an upstream location of the pre-purifier device, or even using a synthetic air stream (e.g., a mixture of oxygen and nitrogen streams taken from an air separator); and (b) depressurizing the pre-purification container by releasing most of the auxiliary purge gas and any oxygen-enriched purge gas remaining in the pre-purification container. Alternatively, step (iv) may also include a single step: repressurizing the pre-purification container portion to a predetermined intermediate pressure using a nitrogen-enriched gas, preferably using a nitrogen-enriched gas with a nitrogen concentration greater than 85%, until the oxygen concentration in the pre-purification container is less than 30% molar volume, and more preferably less than or equal to about 26% molar volume.

[0018] The thermal regeneration of the pre-purification vessel is preferably performed at a lower pressure, such as 1.0 bar to 2.0 bar, compared to the higher pressure maintained during the purification process, and must be performed at a temperature of at least 150°C to meet appropriate safety requirements. The heating step in the thermal regeneration process is typically performed by heating the purge gas to generate a hot purge gas stream, which is fed into the vessel via the outlet and passes through the layers of the pre-purification vessel in the reverse order of the pre-purification process. In many applications of the method of the invention, the purge gas may be taken from the distillation column of a cryogenic air separator as part of the oxygen product gas, or from an oxygen-enriched boiling material, or from exhaust gas extracted from an argon condenser. The catalyst layer and adsorbent layer are regenerated as the oxygen-enriched hot purge gas passes through the various layers of the pre-purification vessel. The oxygen-enriched purge gas is typically discharged from the pre-purification vessel via the inlet. After heating and regenerating the catalyst and adsorbent layers, the adsorbent and catalyst layers in the pre-purification vessel are then cooled with a cold, oxygen-enriched purge gas, typically at a temperature of about 10°C to 50°C, flowing through the vessel in the same direction as the hot purge gas. Following cooling, an auxiliary purge gas is used to dilute the oxygen concentration of the residual gas in the pre-purification vessel, and the vessel is then repressurized to the higher operating pressure required for the pre-purification process.

[0019] As described above, the regeneration step is performed within a predetermined time period, often referred to as the cycle time. After this period, the pre-purification unit's service or function is switched, bringing the previously regenerated container "online" and initiating the purification process, while the container that previously purified the feed air is "offline" and initiating the regeneration process. Typical pre-purification cycle times for air separation equipment used to produce high-purity or ultra-high-purity nitrogen range from approximately 360 minutes to 1200 minutes (i.e., the total cycle time includes blending, purification, and regeneration services). Each pre-purification unit alternates between purification and regeneration services to maintain a continuous production of purified air that is substantially free of carbon dioxide, water, carbon monoxide, hydrogen, and other impurities.

[0020] Preferably, the pre-purification vessel is densely loaded as shown in the accompanying drawings. Dense loading provides the most consistent and uniform packing of adsorbent and catalyst, with minimal leveling of the desired layers. Furthermore, dense packing minimizes adsorbent settling. Such dense packing is optional for pre-purifiers designed for carbon monoxide and hydrogen removal and can be used in all layers of the bed to ensure integrity and uniform depth. Since the relatively thin layers in the second purification section for carbon monoxide and hydrogen removal comprise multiple hogallataic layers and adsorbent layers, as well as any noble metal-based catalysts that can be used, it is important to minimize layer shift and / or settling to maintain a uniform layer depth throughout the life of the pre-purifier unit.

[0021] Now go to Figure 2 The diagram schematically illustrates a dual-bed temperature-switching adsorption prepurifier device 10. The dual-bed temperature-switching adsorption prepurifier device 10 includes two parallel prepurification beds 20 and 40. Each of the prepurification beds 20 and 40 includes cylindrical containers 21 and 41 and a packed bed comprising multiple adsorbent layers and / or catalyst layers.

[0022] Compressed purified air stream 15 can be guided via conduits through streams 31 and 51 toward either of the parallel pre-purification beds 20 and 40. Valves 32 and 52 control the flow of feed air into the pre-purification beds 20 and 40, respectively, and the pre-purified air is discharged from the pre-purification beds 20 and 40 via conduits 33 and 53, which include valves 34 and 54 to control the flow of the pre-purified air stream through them. Conduits 33 and 53 are connected to discharge compressed and pre-purified air stream 60, which is guided to the cold chamber of the air separation unit.

[0023] As discussed in more detail below, the oxygen-enriched purge gas stream 65 is optionally heated by a heat exchanger or an electric heater 66 and enters the pre-purification beds 20 and 40 through conduits 35 and 55. The oxygen-enriched purge stream regenerates the adsorbent contained in the pre-purification beds 20 and 40. The oxygen-enriched purge streams within conduits 35 and 55 are controlled by valves 36 and 56, respectively. A more or less continuous effluent carrying water vapor, carbon dioxide, and other impurities previously adsorbed in the pre-purification beds 20 and 40 passes through conduits 37 and 57 and is discharged as a waste stream 67 that can be discharged into the atmosphere. The flow of the effluents within conduits 37 and 57 is controlled by valves 38 and 58, respectively.

[0024] For a temperature-swing adsorption process performed within a dual-bed temperature-swing adsorption prepurifier, it is desirable to continuously flow dried, prepurified feed air into the cold chamber of the associated air separation unit. This is accomplished using at least two prepurification beds 20 and 40, where at least one prepurification bed is online and adsorbs or catalyzes impurities in the air, while at least another prepurification bed is offline and regenerated. The online prepurification bed can only remain online until it reaches its capacity to adsorb impurities and impurity breakthrough occurs. The breakthrough point is typically defined by the time required for contaminants (e.g., water vapor and carbon dioxide) to reach unacceptable levels at the outlet (indicating that the contaminants saturate the prepurification bed). Once the breakthrough point is reached, the online prepurification bed is taken offline and the previously regenerated bed is brought online to adsorb and / or catalyze impurities.

[0025] In the temperature-switching adsorption process of this invention, a complete cycle typically involves up to eight steps, with each pre-purified bed undergoing consecutively repeated steps. These eight steps are: "blending"; "purification"; "reduced pressure"; "hot purging"; "cold purging"; "partial repressurization"; "partial reduced pressure"; and "complete repressurization". Table 1 below is in conjunction with... Figure 2 The correlation of performance of multiple steps within a pre-purification cycle using two pre-purification beds 20 and 40 and an auxiliary purge gas of air is shown, which will be described in more detail in the following paragraphs.

[0026]

[0027] Table 1

[0028] During the 'blending' step, both pre-purified beds 20 and 40 are in an "online" state, with valves 32, 34, 52, and 54 open, while valves 36, 38, 56, and 58 are closed. During this step, compressed purified air stream 15 is uniformly split between the two beds, and there is no oxygen-enriched purge gas stream 65 in the system. When online, pre-purified beds 20 and 40 are adsorbing water vapor, carbon dioxide, and other contaminants, while any catalyst present would oxidize impurities such as carbon monoxide and hydrogen. The purpose of this 'blending' step is to dilute the residual heat remaining in the pre-purified beds during regeneration and to further dilute the oxygen content of the resulting blended stream, thereby preventing the heated or oxygen-enriched stream from being fed back into the cold chamber of the air separator.

[0029] Following a 'blending' step of approximately 30 minutes, one of the pre-purified beds 20 undergoes a depressurization or 'reduction' step and becomes offline, while the other pre-purified bed 40 receives the complete feed stream and undergoes a 'purification' step, in which water vapor, carbon dioxide, and other impurities such as nitrous oxide, hydrocarbons, carbon monoxide, and hydrogen are removed. The "offline" pre-purified bed 20 is typically referred to as undergoing regeneration. Such regeneration is accomplished through five or six different steps, which sequentially include: (i) 'depressurization'; (ii) 'hot purging'; (iii) 'cold purging'; (iv) 'partial repressurization' using an auxiliary purging gas; (v) 'partial depressurization' (optional); and (vi) 'full repressurization' using air. During 'depressurization', the pre-purified bed 20 is depressurized from the operating pressure to a lower pressure called the regeneration pressure, which is less than approximately 6.0 bar and more preferably less than 2.0 bar and typically just above atmospheric pressure. This is accomplished by closing valves 32, 34, and 36 while simultaneously opening valve 38. The 'decompression' process typically lasts about 15 minutes, although the duration of the 'decompression' step can vary depending on equipment constraints or process limitations. Once decompression is achieved, the 'hot purge' step begins by heating the oxygen-enriched purge gas stream 65 to a temperature above the feed temperature, preferably at least 150°C, depending on the pre-purification process and material constraints, and typically not exceeding about 190°C due to the high oxygen concentration in the purge gas stream. During this 'hot purge' step, valve 36 is open, allowing the heated oxygen-enriched purge gas stream to pass through conduits 35 and 37 through the pre-purification bed 20.

[0030] After a certain period of time, in this example, after 163 minutes, the oxygen-enriched purge gas stream bypasses heater 66 or heater 66 is turned off, thereby reducing the temperature of the oxygen-enriched purge gas stream to near ambient conditions and typically less than or equal to about 50°C. This initiates the 'cold purge' step, which continues to purge using the oxygen-enriched purge gas stream 65 without heat. This 'cold purge' step lowers the temperature of the pre-purified bed 20 and allows the hot front to advance through the pre-purified bed. In this example, the 'cold purge' step lasts approximately 272 minutes.

[0031] Then, a 'partial repressurization' step is performed by closing valves 36 and 38 and opening valve 72 to introduce auxiliary purge gas 70 via conduit 73 into the pre-purification bed 20 for a specified duration (e.g., 6 to 15 minutes) and / or until the pre-purification container 20 reaches an intermediate pressure between the regeneration pressure and the operating pressure. Preferably, the auxiliary purge gas is introduced into the pre-purification container near the clean ends of the purge valves and the pre-purification container (e.g., near valves 36, 56, and outlet 23), and the auxiliary purge gas and any residual oxygen-enriched purge gas are removed from the dirty ends of the pre-purification container (e.g., near inlet 22). This preferred arrangement ensures that no oxygen-enriched gas is blocked at or near the clean ends of the purge valves or the pre-purification container after the complete repressurization step.

[0032] In embodiments using clean, dry air or synthetic air as auxiliary purge gas 70, partial repressurization continues for approximately 6 minutes, followed by partial depressurization of the pre-purified bed 20 by opening valve 38 and closing valve 72 while keeping valves 36, 34, and 32 closed for an additional 9 minutes. The partial depressurization step ends when the oxygen concentration in the pre-purified bed decreases to less than or equal to approximately 30% molar volume, and more preferably less than or equal to approximately 26% molar volume.

[0033] In embodiments where a nitrogen stream is used as the auxiliary purge gas 70, the nitrogen concentration of the nitrogen stream is preferably higher than 85% molar volume, and the partial repressurization step can last up to 15 minutes. The partial repressurization step ends when the oxygen concentration in the pre-purified bed decreases to less than or equal to about 30% molar volume, and more preferably less than or equal to about 26% molar volume.

[0034] Then, by keeping valves 34 and 38 closed and opening valve 72 or 32, the regeneration process continues with the 'full repressurization' step. If valve 32 is open, this allows a portion of the compressed purified air stream 15 to pressurize the pre-purified bed 20 to the full operating pressure. Alternatively, if the auxiliary purge gas is an air stream or a synthesis air stream, valve 72 is opened to pressurize the pre-purified bed 20 back to the full operating pressure. Once pressurized to the operating pressure, both pre-purified beds 20 and 40 enter the 'blending' step, therefore valves 32, 34, 52, and 54 are fully open, allowing the compressed purified air stream 15 to be uniformly split between pre-purified beds 20 and 40 and purified. After a certain period of time in the 'blending' step, the pre-purified beds switch over, and pre-purified bed 20 is online in the 'purification' step, while pre-purified bed 40 undergoes a series of regeneration steps as outlined above with reference to Table 1.

[0035] While the systems and methods of the present invention have been described with reference to one or more preferred embodiments, it should be understood that various additions, changes, and omissions may be made without departing from the spirit and scope of the invention as set forth in the appended claims. For example, the systems and methods disclosed herein are intended for applications using thermal regeneration and temperature swing adsorption prepurification technologies, and it is contemplated that the systems and methods of the present invention can be adjusted or further modified for use in conjunction with pressure swing adsorption prepurification devices and / or hybrid prepurifier devices using both pressure swing adsorption prepurification and temperature swing adsorption prepurification technologies.

Claims

1. A method for regenerating a pre-purified container, the method comprising the following steps: (i) Reduce the pressure of the pre-purification container to the regeneration pressure, the pre-purification container having one or more layers of adsorbent and / or catalyst disposed therein; (ii) Heating the one or more layers of adsorbent material and / or the one or more layers of catalyst material placed in the pre-purification container with hot oxygen-enriched purge gas to desorb water and carbon dioxide in the one or more layers; (iii) Cool the one or more layers of adsorbent and / or the catalyst layer in the pre-purification container to a temperature suitable for the pre-purification process using a cold oxygen-enriched purge gas; (iv) After the cooling step, the pre-purified container is partially repressurized using an auxiliary purge gas to dilute the oxygen concentration of the gas contained in the pre-purified container. (v) The pre-purification container is fully repressurized to the working pressure for pre-purifying the feed gas, wherein the oxygen concentration of the gas in the repressurized pre-purification container is less than or equal to 30% molar volume.

2. The method according to claim 1, wherein the oxygen concentration of the gas in the pre-purified container after repressurization is less than or equal to 26% molar volume.

3. The method of claim 1, wherein the step of partially repressurizing the pre-purification container with an auxiliary purge gas further comprises partially repressurizing the pre-purification container to an intermediate pressure with an auxiliary purge gas; then depressurizing the pre-purification container and releasing the auxiliary purge gas and any oxygen-enriched purge gas remaining in the pre-purification container.

4. The method according to claim 1, wherein the step of partially repressurizing the pre-purification container using an auxiliary purge gas further comprises partially repressurizing the pre-purification container to an intermediate pressure using a nitrogen-rich gas with a nitrogen concentration higher than 85% molar volume, thereby diluting the oxygen concentration of the gas remaining in the pre-purification container.

5. The method according to claim 1, wherein the temperature of the hot oxygen-enriched purging gas is at least 150°C.

6. The method according to claim 1, wherein the temperature of the cold oxygen-enriched purge gas is lower than or equal to 50°C.

7. The method of claim 1, wherein the pre-purification container is coupled to an air separation device, and the feed gas is air, wherein the one or more adsorbents in the pre-purification container comprise activated alumina, silica gel, zeolite-based molecular sieves, X-type zeolite, or combinations thereof, and are configured to remove impurities from the feed gas, including water, carbon dioxide, and other contaminants.

8. The method of claim 7, wherein the one or more catalysts in the pre-purification vessel comprise a hogallat catalyst or a noble metal catalyst and are configured to remove impurities, including hydrogen and carbon monoxide.

9. The method of claim 1, wherein the pre-purification container is connected to an air separation device, and the hot oxygen-enriched purge gas and the cold oxygen-enriched purge gas are taken from the oxygen-enriched stream of the distillation column system of the air separation device.

10. The method of claim 9, wherein the step of heating the one or more layers of adsorbent material and / or the one or more layers of catalyst material with the hot oxygen-enriched purge gas further comprises heating the oxygen-enriched stream with an electric heater, a gas heater or a steam heater.

11. The method of claim 1, wherein the pre-purification container is coupled to an air separation device that generates argon, and the hot oxygen-enriched purge gas and the cold oxygen-enriched purge gas are oxygen-enriched streams taken from an argon condenser associated with the air separation device.

12. The method of claim 3, wherein the regeneration pressure is less than 6.0 bar; the working pressure is greater than or equal to 6.0 bar; and the intermediate pressure is between the regeneration pressure and the working pressure.

13. The method of claim 3, wherein the pre-purification container is coupled to an air separation device, and the auxiliary purge gas further comprises a dry air stream obtained downstream of the pre-purifier device associated with the air separation device, or a split portion of feed air obtained upstream of the pre-purifier device associated with the air separation device, or a synthetic air stream obtained from the air separation device.

14. The method of claim 3, wherein the auxiliary purge gas is introduced into the pre-purification container at or near the outlet via an auxiliary purification control valve, and during depressurization, the auxiliary purge gas and any remaining gas in the pre-purification container are released at or near the outlet via a partial depressurization control valve or the depressurization control valve.

15. The method of claim 4, wherein the pre-purification container is connected to an air separation device, and the nitrogen-rich gas is taken from the air separation device or a nitrogen storage tank.

16. The method of claim 4, wherein nitrogen-rich gas is introduced into the pre-purification container at or near the outlet via an auxiliary purge gas control valve.

17. The method of claim 4, wherein the regeneration pressure is less than 6.0 bar; the working pressure is greater than or equal to 6.0 bar; and the intermediate pressure is between the regeneration pressure and the working pressure.

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