METHOD FOR OPERATING AN ADSORBER ARRANGEMENT AND ADSORBER ARRANGEMENT

Abstract

Method for operating an adsorber arrangement comprising a first and a second adsorber device, arranged in parallel between an upstream process device providing a process gas and a downstream process device receiving a purified process gas. The method comprising during a process of purifying the process gas with the first adsorber device, cooling the second adsorber device by passing a portion of purified process gas, received from the first adsorber device, through the second adsorber device; and directing the process gas portion that has passed through the second adsorber device to the upstream process device. Then, the first and the second adsorber devices are sequentially coupled, such that process gas from the upstream process device passes through the second adsorber device for cooling the second adsorber device, and then through the first adsorber device. Finally, purified process gas is received at the downstream process device from the first adsorber device.

Claims

1. Method for operating an adsorber arrangement (1), the adsorber arrangement (1) comprising a first (10) and a second (20) adsorber device, arranged in parallel between an upstream process device (2) providing a process gas and a downstream process device (3) receiving a purified process gas, the method comprising the steps of: a) during a process of purifying the process gas with the first adsorber device, (10) cooling the second adsorber device (20) by: passing a portion of purified process gas, received from the first adsorber device (10), through the second adsorber device (20) and directing the process gas portion that has passed through the second adsorber device (20) to the upstream process device (2); b) sequentially coupling the first (10) and the second (20) adsorber devices, such that process gas from the upstream process device (2) passes through the second adsorber device (20) for cooling the second adsorber device (20), and then through the first adsorber device (10); and c) receiving purified process gas at the downstream process device (3) from the first adsorber device (10).

2. Method according to claim 1, wherein the step of cooling the second adsorber device comprises: directing the portion of purified process gas, received from the first adsorber device (10) to an outlet of the second adsorber device (20), receiving, at an inlet of the second adsorber device (20), the process gas portion that has passed through the second adsorber device (20) and directing said process gas portion to the upstream process device (2); and wherein the step of sequentially coupling the first (10) and the second (20) adsorber devices comprises: directing the process gas from the upstream process device (2) to the inlet of the second adsorber device (20), receiving, at the outlet of the second adsorber device (20), the process gas that has passed through the second adsorber device (20) and directing this process gas to the first adsorber device (10).

3. Method according to claim 1, wherein the step of sequentially coupling the first (10) and the second (20) adsorber devices comprises: decoupling a direct flow from the upstream process device (2) to the first adsorber device (10).

4. Method according to claim 3, wherein the step of decoupling the direct flow from the upstream process device (2) to first adsorber device (10) comprises: increasing a mass flow (.sub.2) of the process gas portion from the upstream process device (2) through the second adsorber device (20); merging, upstream of the first adsorber device (10), the process gas portion that has passed through the second adsorber device (20) with the process gas that is directed from the upstream process device (2) to the first adsorber device (10); and passing a full mass flow (.sub.max) of the process gas provided by the upstream process device (2) through the first adsorber device (10).

5. Method according to claim 4, wherein the mass flow (.sub.2) of the process gas portion through the second adsorber device (20) regulated depending on the temperature of the second adsorber device (20) and the temperature of the first adsorber device (10).

6. Method according to claim 3, further comprising: after decoupling the first adsorber device (10) from the upstream process device (2), passing the full mass flow (.sub.max) of the process gas provided by the upstream process device (2) through the second adsorber device (20) and through the first adsorber device (10) sequentially.

7. Method according to claim 3, further comprising: after decoupling the first adsorber device (10) from the upstream process device (2), decoupling the second adsorber device (20) from the first adsorber device (10).

8. Method according to claim 7, further comprising: during the step of decoupling the second adsorber device (20) from the first adsorber device (10), coupling the second adsorber device (20) with the downstream process device (3).

9. Method according to claim 8, further comprising: after decoupling the second adsorber device (20) from the first adsorber device (10), passing a full mass flow (.sub.max) of the process gas provided by the upstream process device (2) through the second adsorber device (20); receiving purified process gas at the downstream process device (3) from the second adsorber device (20); decoupling the first adsorber device (10) from the other components of the adsorber arrangement (1); and after decoupling the first adsorber device (10) from the other components of the adsorber arrangement (1), regenerating the first adsorber device (10) by heating the first adsorber device (10).

10. Method according to claim 9, further comprising: after regenerating the first adsorber device (10), cooling the first adsorber device (10).

11. Method according to claim 1, wherein the purified process gas contains at most 1 ppm impurities.

12. Method according to claim 1, wherein during the step of coupling the first (10) and the second (20) adsorber devices, the mass flow of the process gas portion, that first passes through the second adsorber device (20) to cool the second adsorber device (20) and then passed through the first adsorber device (10), regulated such that a temperature of the first adsorber device (10) is stable at (203) K, preferably at (202) K.

13. Method according to claim 1, wherein a time interval for the step of sequentially coupling the first (10) and the second (20) adsorber devices is larger than one hour, larger than two hours or larger than five hours.

14. Method according to claim 1, wherein the step of sequentially coupling of the first (10) and the second adsorber devices (20) is started if an adsorption capacity of the first adsorber device (10) is more than 50%, preferably more than 60%, or more preferably more than 70% of its maximum adsorption capacity.

15. Adsorber arrangement (1) for purifying a process gas comprising: a first (10) and a second adsorber device (20), arranged in parallel between an upstream process device (2) providing a process gas and a downstream process device (3) receiving purified process gas; a duct system comprising ducts (4, 5, 6, 12, 13, 16, 18, 22, 23, 26, 28) and controllable valves (11, 14, 15, 17, 21, 24, 25, 27) for directing the process gas; and a control device (7) for controlling the controllable valves (11, 14, 15, 17, 21, 24, 25, 27), wherein the control device (7) is configured to perform a method of claim 1.

Description

[0071] In the following, embodiments of adsorber arrangements and methods and devices relating to the operation of adsorber arrangements are described with reference to the enclosed drawings.

[0072] FIG. 1 shows a schematic process flow diagram of a first embodiment of an adsorber arrangement;

[0073] FIG. 2 shows a schematic process flow diagram of a second embodiment of an adsorber arrangement;

[0074] FIG. 3 a) shows a third embodiment of an adsorber arrangement operated in a first cleaning mode;

[0075] FIG. 3 b) shows the third embodiment of an adsorber arrangement operated in a partially sequential cleaning mode;

[0076] FIG. 3 c) shows the third embodiment of an adsorber arrangement operated in a sequential cleaning mode;

[0077] FIG. 3 d) shows the third embodiment of an adsorber arrangement operated in a second cleaning mode

[0078] FIG. 4 shows a diagram with an example of a mass flow through one adsorber device in a time interval according to one embodiment of the method; and

[0079] FIG. 5 shows a diagram with a mass flow through the first and the second adsorber device in a time interval comprising three switching cycles.

[0080] FIG. 1 shows a schematic process flow diagram of a first embodiment of an adsorber arrangement 1, which is part of a process engineering arrangement 100. Further, an upstream process device 2, which is implemented as a column 2, provides process gas to the adsorber arrangement 1. The adsorber arrangement 1 comprises a first adsorber device 10, a second adsorber device 20, several ducts 4, 5, 6, 12, 13, 16, 18, 22, 23, 26, 28, and several controllable valves 11, 14, 15, 17, 21, 24, 25, 27. The first and the second adsorber device 10, 20 are arranged in parallel between the column 2 and a downstream process device 3, which can be a heat exchanging device 3 or a vessel to store a purified process gas obtained from the adsorber arrangement 1.

[0081] In this embodiment, the adsorber arrangement 1 is employed to purify a cryogenic process gas, which consists of approximately 99.5% helium with the residual 0.5% being impurities like neon and/or hydrogen. The process gas is provided at 202 K from the column 2 at a pressure of approximately 18 bar. Likewise, the adsorber devices 10, 20 need to be operated at this temperature to clean the process gas. In operation, a purified process gas with a helium content of at least 99.9999% is obtained, which corresponds to the Helium 6.0 specification of Linde AG. This purified process gas is delivered to the heat exchanging device 3, where it is further cooled down. By reducing the pressure to approximately ambient pressure, the helium stream is liquefied at a temperature of about 4 K.

[0082] The operation of the adsorber arrangement 1 is now explained in different operational modes for the adsorber arrangement 1. The operation of single adsorber devices 10, 20 in operation modes may be different from what is described in the following.

[0083] In a first cleaning mode, the column 2 provides the process gas at a full mass flow of 700 g/s via the process gas duct 4. In the first cleaning mode, the first adsorber device 10 is operated in a cleaning mode while the second adsorber device 20 is regenerated and/or pre-cooled. Therefore, inlet valve 11 is open, such that the full mass flow of the process gas can pass the inlet valve 11 to be directed to the feed duct 12 to the first adsorber device 10. Likewise, the inlet valve 21 is closed and no process gas enters the feed duct 22 of the second adsorber device 20 via this valve. The process gas passes the first adsorber device 10, thus being purified, and a purified process gas is obtained in the outlet duct 13 of the first adsorber device 10. The outlet valve 14 is fully opened, such that the full mass flow can pass and be directed to the heat exchanging device 3 via the purified process gas duct 5. In this first cleaning mode, the other valves 15, 17, 24, 25, 27 are closed and no mass flow of process gas occurs in the ducts 16, 18, 22, 23, 26, 28. A mass flow may occur in the return duct 6, because of evaporation of a fraction of the liquefied helium in and/or after the heat exchanging device 3, which is due to throttling of the purified process gas and/or flash gas formation. This portion is fed back to the upstream process device 2.

[0084] In a first cooling mode, which starts for example from the setting of the first cleaning mode, the second adsorption device 20 is regenerated and pre-cooled to a temperature of 30 K by opening the outlet valve 24 and the return valve 27. Thus, a portion of the purified process gas is directed through the second adsorber device 20. The mass flow can be controlled by either restricting the mass flow through the outlet valve 24 or through the return valve 27. For example, the outlet valve 24 of the second adsorber device 20 is opened a little bit, such that a portion of the full mass flow from the purified process gas duct 5 can enter the outlet duct 23 of the second adsorber device 20 via the outlet valve 24. The outlet valve 24 is set such that a mass flow of 35-70 g/s, corresponding to 5-10% of the full mass flow, can pass through the valve 24. This portion enters the second adsorber device 20 from its outlet duct 23, passes through it, cooling down the adsorbent, and enters the feed duct 22 of the second adsorber device 20. The process gas portion was heated up while passing through the second adsorber device 20 and needs to be cooled down, before it can be processed again. Therefore, the return valve 27 is opened such that the heated process gas is directed from the feed duct 22 to the return duct 6 and is fed back to the upstream process device 2. The further valves 15, 17, 21 are closed in this mode. In this first cooling mode, the second adsorber device 20 is cooled down to a first target temperature.

[0085] In a second cooling mode, the second adsorber device 20 is operated to reach its target operational temperature of 203 K in a regular feeding mode. For this, the inlet valve 21 is set such that a fraction of the total mass flow of the process gas can enter the feed duct 22 of the second adsorber device 20. From there, it is fed to the inlet of the second adsorber device 20 and is obtained in the outlet duct 23 of the second adsorber device 20. The outlet valve 24 is fully closed in this operational mode. Instead, the bypass valve 25 is opened, such that the process gas portion is directed from the outlet duct 23 via the bypass duct 26 to the feed duct 12 of the first adsorber device 10. Thus, the first and the second adsorber device are coupled sequentially. The first adsorber device 10 is still operated in the cleaning mode, wherein the process gas is fed via the inlet valve 11 to the feed duct 12. In the feed duct 12, the bypassed gas portion, which has passed the second adsorber device 20 and has a potentially elevated temperature, merges with the process gas which was directed via the inlet valve 11 and the full mass flow passes through the first adsorber device 10. The mass flow of the bypassed gas portion with elevated temperature is chosen such that the temperature of the merged process gas passing through the first adsorber device 10 is approximately (221) K. This can be measured, for example, by a temperature sensor (not shown) located at the inlet of the first adsorber device 10. The purified process gas is obtained in the outlet duct 13, from where it is directed via the fully opened outlet valve 14 into the purified process gas duct 5 and to the heat exchanging device 3. The valves 15, 17, 24, 25, 27 are fully closed in this operational mode. In this second cooling mode, the second adsorber device 20 is operated in a cleaning mode, however, the mass flow is restricted and the actual cleaning of the process gas is done by the first adsorber device 10.

[0086] The second cooling mode corresponds to the partially sequential cleaning mode which was described before, because a portion of the process gas passes through the second and the first adsorber devices 20, 10 sequentially.

[0087] In a sequential cleaning mode, the full mass flow of the process gas is directed from the process gas duct 4 via the inlet valve 21 of the second adsorber device 20 to the feed duct 22. From there, it passes the second adsorber device 20, thus further cooling down the second adsorber device 20. From the outlet duct 23, the full mass flow is directed via the bypass duct 26 and the fully opened bypass valve 25 to the feed duct 12 of the first adsorber device 10. It passes the first adsorber device 10, wherein it is cleaned to obtain the purified process gas in the outlet duct 13. From there, it is directed via the outlet valve 14 to the purified process gas duct 5. In this operational mode, the second adsorber device 20 will reach the conditions to be operated in the cleaning mode without needing the first adsorber device 10 to ensure the purity of the purified process gas. The valves 11, 15, 17, 24, 27 are fully closed in this operational mode. As described above, the second adsorber device 20 is further cooled, so it is noted that the sequential cleaning mode could also be considered as a final stage of the second cooling mode.

[0088] In a second cleaning mode, the full process gas mass flow is directed from the process gas duct 4 via the inlet valve 21 to the feed duct 22, through the second adsorber device 20 to the outlet duct 23 ad via the outlet valve 24 to the purified process gas duct 5 and to the storing vessel 3. The first adsorber device 10 does not participate in the cleaning of the process gas. Thus, the first adsorber device 10 is decoupled from the second adsorber device 20. In this mode, the first adsorber device 10 may be operated in a regeneration mode.

[0089] A cleaning mode for single adsorber devices 10, 20 can be defined as providing a process gas to the inlet of the adsorber device 10, 20, and obtaining a process gas at the outlet of the adsorber device 10, 20. When the adsorber device 10, 20 is at its target operational temperature and has adsorption capacity left, the obtained process gas is purified process gas.

[0090] The regeneration mode for single adsorber devices 10, 20 may comprise the following procedure. Note, that additional valves and ducts may be necessary for operation in this regeneration mode, which are not shown in FIG. 1. For example the first adsorber device 10 is regenerated. For this, all valves 11, 14, 15 are fully closed. An electrical heating device (not shown) heats up the adsorber device 10, 20. Further, a purge gas is provided to the feed duct 12 of the first adsorber device 10. The purge gas may have a temperature of 120-150 K and a pressure of 1 mBar-3 Bar. By purging the first adsorber device 10 with this purge gas, the impurities which have been released during the warm up process are removed from the isolated system and are transported with the purge gas. The contaminated purge gas can be processed by another device, which is not shown in FIG. 1.

[0091] The first and the second cooling modes which were described above can be adapted such that the first adsorber device 10 is cooled down, while the second adsorber device 20 is performing the actual cleaning of the process gas.

[0092] By cyclically operating the adsorber arrangement 1 in the operational modes as described, a continuous mass flow of purified helium with a purity of 99.9999% can be obtained.

[0093] FIG. 2 shows a schematic process flow diagram of a second embodiment of an adsorber arrangement 1, which is arranged between an upstream process device 2 and a downstream process device 3, which together form a process engineering arrangement 100. The setup of this embodiment has controllable diverting valves 11, 12, 21, 22 and a control device 7, is the control device 7 being configured to control the controllable diverting valves 11, 12, 21, 22 via signaling lines 8. The signaling lines 8 can be implemented as wire connections or also as a wireless link, e.g. Wi-Fi, Bluetooth, or else. The controllable diverting valves 11 and 21 are implemented with two inlets and one outlet each and can be set such that two gas portions are merged to form one larger gas portion. The controllable diverting valves 12 and 22 are implemented with one inlet and three outlets each and can be set to split an incoming mass flow into up to three portions, wherein each portion can have a mass flow with an arbitrary fraction of the incoming mass flow. Further, in this second embodiment the first and the second adsorber devices 10, 20 are equipped with temperature sensors 19, 29 which are configured to report a temperature of the devices to the control device 7. This embodiment can have the same functionality as the embodiment of FIG. 1 and will be described in the following.

[0094] In a first cleaning mode, the first adsorber device 10 is operated in the cleaning mode. For this, the diverting valve 11 is triggered by the control device 7 such that the full mass flow of the process gas from the process gas duct 4 passes to the first adsorber device 10. Note, that the feed duct and the outlet duct are not marked with separate reference signs in FIG. 2. The diverting valve 12 is set such that the full purified process gas passes to the purified process gas duct 5 and to the downstream process device 3. The other diverting valves 21, 22 are fully closed.

[0095] After a certain time interval being operated in the first cleaning mode, the control device 7 may trigger a change in the operational mode to a first cooling mode. The time interval may be predefined or the change may be triggered by a signal, e.g. after a certain total mass of purge gas has passed through the second adsorber device 20, while the adsorber arrangement 1 is operated in the first cleaning mode. The control device 7 triggers the diverting valve 12 such that a portion of the purified process gas passes into the bypass duct 16 and triggers the diverting valve 21 such that this portion passes from the bypass duct 16 to the second adsorber device 20. Further, the diverting valve 22 is triggered such that after passing through the second adsorber device 20, the gas portion is directed via the diverting valve 22 to the return duct 28, 6. The other outlets of the diverting valve 22, which lead to the purified process gas duct 5 or the bypass duct 26 are closed in this mode. Note that in this embodiment, the portion of the purified process gas that is employed to cool down the second adsorber device 20 is directed in the regular direction, i.e. from the inlet to the outlet through the second adsorber device 20, which is a difference to the first embodiment of FIG. 1.

[0096] After a time interval being operated in the first cooling mode, the control device 7 may trigger a change in the operational mode to a second cooling mode. The change may be triggered after a predefined time interval or by a sensor signal. For example, the temperature sensor 29 reports that the second adsorber device 20 has reached a predefined threshold temperature. The control device 7 triggers the diverting valve 21 to partially open such that a portion of the process gas passes from the process gas duct 4 to the second adsorber device 20. The mass flow of this portion is a fraction of the total mass flow provided by the upstream process device 2 and is controlled by the control device 7. Further, the control device 7 triggers the diverting valve 22 to direct the gas portion, after passing the second adsorber device 20, to the bypass duct 26 and triggers the diverting valve 11 such that the remaining portion of the process gas from the process gas duct 4 and the portion from the bypass duct 26 merge and form the process gas with the total mass flow to pass through the first adsorber device 10. Thereby, the total mass flow of the process gas is cleaned by the first adsorber device 10 and a portion of the process gas is employed to cool the second adsorber device 20.

[0097] After a time interval being operated in the second cooling mode, the control device 7 may trigger a change in the operational mode to a sequential cleaning mode. The change may be triggered after a predefined time interval or by a sensor signal. For example, the temperature sensor 29 reports that the second adsorber device 20 has reached a predefined threshold temperature. In the sequential cleaning mode, which can also be considered as a final stage of the second cooling mode, the control device 7 triggers the diverting valve 21 such that the total mass flow is directed from the process gas duct 4 via the diverting valve 21 through the second adsorber device 20, and further via the diverting valve 22 to the bypass duct 26 and via the diverting valve 11 to the first adsorber device 10. Finally, the purified process gas, after passing the first adsorber device, is directed via the diverting valve 12 to the purified process gas duct 5 and to the downstream process device 3. In this mode, no mass flow occurs from the process gas duct 4 via the diverting valve 11 to the first adsorber device 10.

[0098] After a time interval being operated in the sequential cleaning mode, the control device 7 may trigger a change in the operational mode to a second cleaning mode. The change may be triggered by a sensor signal. For example, a sensor (not shown) may be attached to the outlet of the second adsorber device 20, which detects the purity of the process gas coming from the second adsorber device 20. When the purity reaches the required value and is stable, the second adsorber device can be operated in the cleaning mode without the need for an additional cleaning by the first adsorber device 10. In the second cleaning mode, the control device 7 triggers the diverting valve 22 to direct the total mass flow of the purified process gas to the purified process gas duct 5 and to the downstream process device 3. The diverting valves 11 and 12 are triggered to be fully closed in this mode. The control device 7 may further trigger a regeneration mode for the first adsorber device 10, such that it is purged by purge gas (not shown).

[0099] By cyclically operating the adsorber arrangement 1 in the operational modes as described, a continuous mass flow of purified helium with a purity of 99.9999% can be obtained. For this, the control device 7 is configured to automatically trigger the changes in the operational modes such that at least one of the adsorber devices 10, 20 is operated in the cleaning mode, while the other adsorber device 10, 20 is being regenerated and/or cooled down to the target operational temperature as according to the operational modes described above.

[0100] FIG. 3 a)-d) show a third embodiment of an adsorber arrangement 1 operated in different operational modes. In this third embodiment, many details were left out in order to show a simple setup to understand the different operational modes of the adsorber arrangement 1. In particular, a return duct 6 is not shown in this embodiment and reference numerals for the other ducts are omitted. The thick lines in the FIG. 3 a)-d) mark the flow path of the larger portion of the process gas. The dashed thick line in FIG. 3 b) marks the flow path of a portion of the process gas.

[0101] FIG. 3 a) shows the third embodiment operated in the first cleaning mode, during which the first adsorber device 10 is cleaning the process gas. No process gas passes through the second adsorber device 20.

[0102] FIG. 3 b) shows the third embodiment operated in the partially sequential cleaning mode. For this, a portion of the process gas passes through the second adsorber device 20 and is directed, via the diverting valve 22 to the diverting valve 11, where it merges with the remaining portion of the process gas and the total mass flow passes through the first adsorber device 10 and is thus purified.

[0103] FIG. 3 c) shows the third embodiment operated in the sequential cleaning mode. Here, the full mass flow of the process gas first passes through the second adsorber device 20 and then via the diverting valves 22 and 11 through the first adsorber device 10.

[0104] FIG. 3 d) shows the third embodiment operated in the second cleaning mode, wherein the second adsorber device 20 is purifying the total mass flow of the process gas. No mass flow of process gas occurs through the first adsorber device 10 in this mode.

[0105] FIG. 4 shows a diagram with an example of a mass flow .sub.1 of the process gas through the first adsorber device 10 in a time interval according to one embodiment of the method. In this example, at times before t.sub.0, the mass flow .sub.1 of the process gas through the adsorber device 10 is 0. For example, in this time interval, the adsorber device 10 is warmed up and purged by a purge gas and thus regenerated. At time t.sub.0, the adsorber device 10 is fully regenerated and is pre-cooled by directing purified process gas through the adsorber device 10. The mass flow .sub.c1 of the purified process gas is of the order of 10% of the full mass flow .sub.max. After this pre-cooling procedure at t.sub.1, the adsorber device 10 has to be cooled down to the target operational temperature. Therefore, the mass flow .sub.1 is increased slowly, until it reaches the maximum .sub.max at a time t.sub.2. The time interval t.sub.1-t.sub.2 corresponds to the second cooling mode described with reference to FIG. 1 and/or FIG. 2. At times after t.sub.2, the maximum mass flow .sub.max passes the adsorber device 10.

[0106] FIG. 5 shows a diagram with the mass flow .sub.1, .sub.2 through the first and the second adsorber device 10, 20 of an adsorber arrangement, for example the adsorber arrangement 1 of either FIG. 1, FIG. 2, or FIG. 3 in a time interval comprising three cycles. At times before t.sub.0, the adsorber arrangement 1 is operated in the second cleaning mode. .sub.2, which is the mass flow through the second adsorber device 20, is equal to the total mass flow .sub.max. The first adsorber device 10 is being regenerated.

[0107] At the time point t.sub.0, the first adsorber device 10 is fully regenerated and is being pre-cooled by passing a portion .sub.c1 of the purified process gas through it. At time point t.sub.1 pre-cooling has finished and the switching process starts in order to cool the first adsorber device 10 to the target operational temperature. For this, the adsorber arrangement 1 may be operated in the second cooling mode or the partially sequential cleaning mode. A portion of the process gas is directed through the first adsorber device 10, thus .sub.1 increases. The portion that passes the first adsorber device 10 is bypassed to the second adsorber device 20, thus still the total mass flow occurs through the second adsorber device 20. At a time point t.sub.2, the total mass flow is first directed through the first adsorber device 10 and through the second adsorber device 20, which ensures the purity of the purified process gas. This corresponds to the sequential cleaning mode.

[0108] At a time point t.sub.3 the first adsorber device 10 has reached its target operational temperature and can thus be used alone to clean the process gas and provide the required purity. At this time point t.sub.3, the second adsorber device 20 is decoupled from the process gas and is regenerated. This corresponds to the first cleaning mode.

[0109] At time point t.sub.4, the second adsorber device 20 is regenerated and is being pre-cooled by passing a portion .sub.c1 of the purified process gas through it. At time point t.sub.5 pre-cooling has finished and the switching process starts in order to cool the second adsorber device 20 to the target operational temperature. As before, a portion of the process gas is directed through the second adsorber device and .sub.2 increases. The adsorber arrangement 1 is operated in the second cooling mode until time point t.sub.6, when the full mass flow passes through both adsorber devices 10, 20 sequentially, which then corresponds to the sequential cleaning mode.

[0110] At time point t.sub.7 the second adsorber device 20 has reached its target operational temperature and is thus employed to clean the process gas alone, so that the first adsorber device 10 can be regenerated. This corresponds to the second cleaning mode.

[0111] The time point t.sub.8 corresponds to the time point t.sub.0, such that by repeating the process as described above, a cyclical operation of the adsorber arrangement 1 is achieved to provide a continuous flow of purified process gas.

REFERENCE NUMERALS

[0112] 1 adsorber arrangement [0113] 2 upstream process device [0114] 3 downstream process device [0115] 4 process gas duct [0116] 5 purified process gas duct [0117] 6 return duct [0118] 7 controller device [0119] 8 control device signal lines [0120] 10 first adsorber device [0121] 11 inlet valve for the first adsorber device [0122] 12 feed duct for the first adsorber device [0123] 13 outlet duct of the first adsorber device [0124] 14 outlet valve for the first adsorber device [0125] 15 bypass valve [0126] 16 bypass duct [0127] 17 return valve [0128] 18 return duct [0129] 19 temperature sensor [0130] 20 second adsorber device [0131] 21 inlet valve for the second adsorber device [0132] 22 feed duct for the second adsorber device [0133] 23 outlet duct of the second adsorber device [0134] 24 outlet valve for the second adsorber device [0135] 25 bypass valve [0136] 26 bypass duct [0137] 27 return valve [0138] 28 return duct [0139] 29 temperature sensor [0140] 100 process engineering arrangement [0141] t time axis [0142] t.sub.0 time point (starting time of pre-cooling) [0143] t.sub.1 time point (starting time of switching process) [0144] t.sub.2 time point (full gas flow through both adsorber devices sequentially) [0145] t.sub.3 time point (switching to only one adsorber device) [0146] t.sub.4 time point (starting time of pre-cooling the regenerated adsorber device) [0147] t.sub.5 time point (starting time of switching process) [0148] t.sub.6 time point (full gas flow through both adsorber devices sequentially) [0149] t.sub.7 time point (switching to only one adsorber device) [0150] t.sub.8 time point (starting time of pre-cooling the regenerated adsorber device) [0151] t.sub.9 time point (starting time of switching process) [0152] t.sub.10 time point (full gas flow through both adsorber devices sequentially) [0153] t.sub.11 time point (switching to only one adsorber device) [0154] gas flow [0155] .sub.1 process gas flow through first adsorber device [0156] .sub.2 process gas flow through second adsorber device [0157] .sub.c1 pre-cooling purified process gas flow [0158] .sub.max maximum process gas flow