METHOD FOR MANAGING A PRESSURE SWING ADSORPTION GAS TREATMENT UNIT

Abstract

The invention relates to a method for managing a PSA unit having at least N adsorbers arranged in pairs, where each pair is designed to be able to be selectively isolated, a control device, and a plurality of interfaces for accessing instrumentation means of each adsorber, When a first pair is fluidically isolated, the first pair having a first and a second adsorber, the isolating of a third adsorber includes setting the control device to control N-4 adsorbers, fluidically isolating a second pair having the third and a fourth adsorber, isolating one of the first and second adsorbers and the third adsorber, configuring the interfaces so as to swap over the instrumentation means of the other of the first and second adsorbers and the instrumentation means of the fourth adsorber, placing the first and second pairs in fluidic communication, and setting the control device to control N-2 adsorbers.

Claims

1. A method for managing a pressure swing adsorption gas treatment unit, the unit comprising: at least N adsorbers, N being an even number greater than or equal to 6, the N adsorbers being arranged in pairs, a plurality of isolation valves for selectively isolating at least one pair with respect to the unit, a plurality of cycle valves for controlling the pressure cycle of each adsorber, each pair being arranged in such a way as to be isolated selectively, so that isolating a pair allows the two adsorbers of the pair to be fluidically isolated with respect to the unit, the isolating of a pair being performed by closing at least one isolation valve, a control device. a plurality of interfaces for accessing instrumentation means of each adsorber, wherein, when a first pair is fluidically isolated with respect to the unit by the closing of at least one isolation valve, the first pair comprising a first adsorber and a second adsorber, and the control device being configured to control only N-2 adsorbers of the unit, the isolating of a third adsorber comprises the steps of: setting the control device to control only N-4 adsorbers of the unit, fluidically isolating a second pair with respect to the unit by closing at least one isolation valve, the second pair comprising the third adsorber and a fourth adsorber, fluidically isolating one of the first and second adsorbers so that it is isolated from the unit independently of the fluidic isolation of the pair to which it belongs, fluidically isolating the third adsorber so that it is isolated from the unit independently of the fluidic isolation of the pair to which it belongs, while the first and second pairs are fluidically isolated from the unit, configuring the interfaces so as to swap over the instrumentation means of the other of the first and second adsorbers and the instrumentation means of the fourth adsorber, placing the first and second pairs in fluidic communication with respect to the unit by opening at least one isolation valve, setting the control device to control only N-2 adsorbers of the unit.

2. The method according to claim 1, further comprising the step of removing or deactivating a plurality of the cycle valves.

3. The method according to claim 1, further comprising the step of purging one of the first and second adsorbers and the third adsorber.

4. The method according to claim 3, further comprising the step of inerting one of the first and second adsorbers and the third adsorber.

5. The method according to claim 1, wherein the interfaces comprises cables connecting the instrumentation means of each adsorber to the control device, the method comprising the step of changing over the end of the cables that is connected to the instrumentation means of the other of the first and second adsorbers with the end of the cables that is connected to the instrumentation means of the third adsorber.

6. A treatment unit for treating a gas by pressure swing adsorption, for implementing the method according to claim 1, the unit comprising 12 adsorbers.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0057] The invention will be understood better from reading the following description and from studying the accompanying figures. These figures are given only by way of illustration and do not in any way limit the invention.

[0058] FIG. 1 is a schematic depiction of a PSA unit in which the method according to the invention is implemented;

[0059] FIG. 2 is a schematic depiction of the PSA unit of FIG. 1, in which one pair is isolated;

[0060] FIG. 3 is a schematic depiction of the PSA unit of FIG. 2, in which another pair is isolated;

[0061] FIG. 4 is a schematic depiction of the PSA unit of FIG. 3, implementing the method according to the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0062] Reference is made to FIG. 1, which depicts a PSA unit 100 employing 12 adsorbers 1-12. This PSA unit 100 is configured in such a way as to comprise 6 pairs 21-26 of adsorbers (one pair comprising the adsorbers 1 and 2, another pair comprising the adsorbers 3 and 4, etc.). Each pair 21-26 of the PSA unit 100 is designed to be selectively isolated, so that the isolating of a pair allows the two adsorbers of the pair to be fluidically isolated with respect to the unit 100. More specifically, each pair 21-26 can be isolated from the rest of the unit 100 by an isolation valve, not depicted.

[0063] Electing to group the adsorbers 1-12 together in pairs 21-26 for isolating at least one adsorber 1-12 of the unit represents a compromise between the operational flexibility and the complexity of the technical installations of the PSA unit 100.

[0064] The unit 100 further comprises a plurality of cycle valves and a control device for controlling the cycle valves, in order to carry out the pressure cycle, Each adsorber 1-12 is thus controlled by cycle valves assigned to it.

[0065] The unit 100 further comprises a plurality of interfaces for accessing instrumentation means of each adsorber 1-12.

[0066] More specifically, these interfaces comprise electric cables, connecting the instrumentation means of each adsorber 1-12 to the control device.

[0067] The instrumentation means comprise pressure sensors and cycle valve switching devices.

[0068] Thus, the control device is able to read the information delivered by the sensors and control the cycle valves of each adsorber 1-12.

[0069] When a fault on one of the adsorbers 1-12 is detected (or indeed in order to carry out a maintenance operation on one of the adsorbers 1-12), it is possible to elect to fluidically isolate one of the pairs 21-26 by actuating the isolation valve for that pair 21-26. Before proceeding to isolate the pair 21-26, the control device is first of all configured so that it controls just 10 of the 12 adsorbers of the unit (the control device is pre-configured to be capable of controlling selectively either all 12 of the adsorbers of the unit, or 10, or 8, or 6 of the adsorbers of the unit). In all cases, the cycle will be adapted to suit the configuration adopted. As soon as the control device has been configured to control just 10 of the 12 adsorbers of the unit 100, the pair that is to be isolated is then fluidically isolated. This isolation is performed by manual operation of the isolation valve assigned to the pair concerned.

[0070] FIG. 2 shows the unit 100 of FIG. 1, in which a first pair 23. comprising a first adsorber 5 and a second adsorber 6, has been fluidically isolated with respect to the other adsorbers of the unit 100.

[0071] The unit 100 then operates with just 10 adsorbers (those belonging to the pairs 21, 22, 24, 25 and 26).

[0072] Under these conditions of operation of the PSA unit 100, and when there is a desire to fluidically isolate a third adsorber 8 of the unit 100, the following method is implemented.

[0073] With reference to FIG. 3, the starting point is to set the control device so that it controls just 8 adsorbers of the unit 100 (in the example of FIG. 3, the adsorbers of the pairs 21, 22, 25, 26). Next, a second pair 24 is fluidically isolated from the unit 100. This pair 24 comprises the third adsorber 8 and a fourth adsorber 7.

[0074] Working on the assumption that the second adsorber 6 and the third adsorber 8 are defective and that the first adsorber 5 and the fourth adsorber 7 are functional, the method will allow the first 5 and fourth 7 adsorbers to be brought back into operation in order to improve the output of the unit 100.

[0075] The second 6 and third 8 adsorbers are fluidically isolated from the other adsorbers of the unit 100. This operation is achieved by fitting ring seals that act as hermetic plugs so as to prevent any leak of gas from the unit 100, while at the same time allowing these second 6 and third 8 adsorbers to be isolated. This isolation now being independent of the isolation of the pair to which they belong.

[0076] The cycle valves that control these second 6 and third 8 adsorbers can be removed.

[0077] The second 6 and third 8 adsorbers are then purged and inerted so as to allow maintenance operations without the risks associated with the presence of dangerous gases.

[0078] With reference to FIG. 4, the unit 100 is configured in such a way as to allow the first 5 and fourth 7 adsorbers to be brought back into operation within the unit 100.

[0079] That end (or connector) of the electric cables that is connected to the instrumentation means of the first adsorber 5 is changed over with that end of the electric cables that is connected to the third adsorber 8.

[0080] Thus, the control device, when seeking to control the third adsorber 8 will in fact be controlling the first adsorber 5.

[0081] Via this switching-over of the electric cables, the control device will be able to manage the first 5 and fourth 7 adsorbers as if they belonged to the second pair 24.

[0082] The method next comprises the step of placing the first 23 and second 24 pairs in fluidic communication with respect to the unit, by opening the respective isolation valves. Note that because of the hermetic plugs, the second 6 and third 8 adsorbers remain fluidically isolated with respect to the other adsorbers of the unit 100.

[0083] The method next comprises the step of setting the control device to control just 10 adsorbers of the unit (the second 6 and third 8 adsorbers not being used).

[0084] It will be understood that many additional changes in the details, materials, steps and arrangement of parts, which have been herein described in order to explain the nature of the invention, may be made by those skilled in the art within the principle and scope of the invention as expressed in the appended claims. Thus, the present invention is not intended to be limited to the specific embodiments in the examples given above.