PSA installation for oxygen production including a common rotary valve

Abstract

The object of the present invention relates to an installation for the production of oxygen applying the so-called PSA (Pressure Swing Adsorption) technology, comprising a common rotary valve (10) placed on the supply path of tanks (5) configured to be pressurized / depressurized, the installation being able to be housed, in particular, at least partially within a frame. Abstract figure: Fig. 1

Description

Title of the invention: PSA installation for the production of oxygen comprising a common rotary valve

[0001] The subject of the present invention relates to an installation for the production of oxygen applying the so-called PSA technology (Pressure Swing Adsorption) comprising a common rotary valve placed on the supply path of tanks configured to be pressurized / depressurized, the installation being able in particular to be housed at least partially inside a frame.

[0002] Gas separation processes, particularly oxygen separation processes, by pressure- or temperature-controlled adsorption are commonly implemented in industry. In this context, rotary valves are very often used to direct fluids from one or more process sources to one or more process destinations during repeatable cyclic process steps.

[0003] Thus, documents EP1340531, EP1420197, CN112892153, CN112892154, US4705627, US6471744, CN101474520, CN208980325 and EP1872845 describe the use of rotary valves, in particular (for some of these documents) for supplying parallel adsorption chambers with a view to carrying out a PSA cycle.

[0004] However, among other problems encountered, the yields are not optimal for constant production, in particular in the production of oxygen with the devices described in these documents, which is notoriously problematic in industries / installations requiring consistency and quality of production (for example in the hospital environment or more generally in personal care). In addition, the installations described in these documents require, when a rotary valve is placed upstream of the columns and a rotary valve placed downstream of the columns, a synchronization of the valves complicating the implementation of gas production, and more notoriously generating a fluctuation in production over time of the flow of gas produced.

[0005] The aim of the invention is therefore to overcome the drawbacks of the prior art and thus aims to propose an installation which is easier to implement and allows continuous and optimum production of oxygen. Summary of the invention

[0006] To this end, a first aspect of the invention thus relates, in its broadest sense, to an installation for the production of oxygen, said installation comprising at least one air compressor, one oxygen generator and one oxygen compressor, said oxygen generator applying the so-called PSA technology. (Pressure Swing Adsorption) comprising tanks, each tank having two ends and a body at least partially filled with a molecular sieve, open at each of its ends to define between said ends a flow path through the molecular sieve, one of the ends called the first end of each tank being selectively connectable to a source of pressurized or exhausted air to allow a pressurization / depressurization cycle of said tank, each molecular sieve being capable of adsorbing nitrogen molecules and allowing oxygen to pass through under the effect of pressurization of the tank and releasing nitrogen molecules by desorption under the effect of exhausting the tank, in which the installation comprises, for the pressurization / depression of the tanks or at least part of the tanks, a rotary valve common to said tanks,this rotary valve interposed between the first end of each tank and at least one source of compressed air having for each tank to which it is connected at least two angular positions corresponding one, called pressurization position, to a position of supply of pressurized air to said tank, another, called depressurization position, in particular to an equalization position making it possible to balance the pressures between two tanks, to a position of exhausting said tank, characterized in that the second end of each tank opens into a line connecting the second ends of the tanks to each other by a connecting interface, this connecting interface defining two parallel pipes over at least part of their length and each connecting the second end of the tank and the connecting line to each other, each pipe has a non-return valve,the check valves being reversed from one pipe to another.

[0007] The lines connecting the second ends of the tanks to each other by a connecting interface arranged as described above allow continuous production of oxygen while limiting flow rate variations.

[0008] Preferably, the reservoirs comprise columns.

[0009] Preferably, the reservoirs comprise adsorbent beds.

[0010] Preferably, the adsorbent beds comprise molecular sieve.

[0011] Advantageously, each pipe has at least one flow regulator arranged in series with said non-return valve. This flow regulator makes it possible to improve the consistency of oxygen production.

[0012] Preferably, the first end of each tank is furthermore selectively connectable to another tank to allow an equalization phase in the pressurization / depression cycle and in that the rotary valve has for each tank to which it is connected in addition to the pressurization and depressurization positions an equalization position corresponding to a connection position from the tank to another tank. Such a pressure equalization phase makes it possible to improve the consistency of oxygen production by allowing better selectivity of the extracted oxygen.

[0013] Advantageously, the valve is configured to, in at least one angular position, occupy a position corresponding for one of the tanks to the pressurization position of said tank and for the other or another of the tanks to the position corresponding to the depressurization position of said tank. Thus, by varying the pressures of the different tanks asynchronously, it can be envisaged to have a constant production of oxygen.

[0014] Advantageously, at least one of the angular positions of the valve corresponds, for a first tank or a first series of tanks, to a pressurization position of said first tank or the first series of tanks, for a second tank or a second series of tanks, to a depressurization position of said second tank or the second series of tanks, and for the third tank or the third series of tanks to an equalization position of said third tank or the third series of tanks. Thus, the different tanks are, taken all together in the three pressurization modes (pressurized, equalized, depressurized), which guarantees production consistency.

[0015] Such a constant oxygen production is particularly advantageous in applications requiring a regular flow of oxygen, for example in hospitals, hospices, or any other place where people are accommodated requiring an oxygen supply, or in chemical synthesis or production industries requiring a constant supply of oxygen. The invention thus makes it possible to produce the desired oxygen at the place of consumption (or adjacent to this place), without requiring an oxygen buffer tank which may be relatively large depending on the expected demand. The invention thus makes it possible to limit the safety risks linked to the storage of oxygen reserves.

[0016] In one embodiment, the installation according to the present invention has a rotary valve comprising:

[0017] (a) a stator having a stator face and a plurality of openings disposed on the face of the stator and passing through said stator,

[0018] (b) a rotor having a rotor face rotatable about an axis perpendicular to the rotor face in sealing and compressive contact with the stator face to form a rotary valve plane seal defining at least a first and a second chamber on the rotor face, said first and second chambers being arranged such that at least two openings of the stator are placed to coincide jointly and sequentially respectively with said chambers of the rotor face, the stator further comprising a pressurized fluid inlet configured to coincide with only the first chamber, and the rotor comprises at least one exhaust port, the rotor being further configured to occupy an angular position in which the first chamber is in coincidence with the pressurized fluid inlet and the second chamber is in coincidence with the exhaust.

[0019] The "stator", also known as the "fixed barrel", is the functional stationary part of a rotary valve.

[0020] The "rotor," also known as the "moving barrel," is the functional rotating part of a rotary valve, as opposed to the stator.

[0021] By "rotary valve flat seal" is understood in the context of the present invention a sandwiched element of generally flattened shape in contact with both the face of the stator and the face of the rotor and ensuring a seal between the stator and the rotor.

[0022] By "coincide sequentially respectively with said chambers of the rotor face", it is understood that said at least two openings of the stator are placed in such a way that when the rotor rotates, these openings of the stator coincide with said chambers of the rotor face, and this one after the other therefore in a sequential manner.

[0023] By "exhaust", is understood in the context of the present invention an outlet towards the outside of the installation, in particular, of the rotary valve, and in particular of the assembly constituted by the rotor and the stator.

[0024] Preferably, the rotary valve flat seal comprises at least one first lubrication seal in contact with at least one second elastically deformable seal. Thus, thanks to the presence of the elastically deformable seal, the lubrication seal ensures perfect sealing of the rotor-stator assembly of the valve while limiting friction. The mechanical stresses between the rotor and the stator are therefore much lower than those of the prior art, which therefore makes it possible to limit maintenance with the same level, or even a higher level of efficiency given that the lubrication and sealing are better controlled.

[0025] By "lubricating seal", in the context of the present invention is understood a seal whose properties limit friction.

[0026] By "elastically deformable joint", is understood in the context of the present invention a joint which has the property of regaining, at least partially, its shape or its volume, after having lost at least one of the two by compression or extension.

[0027] Thus, in one embodiment, the installation according to the present invention comprises a rotary valve as described above, in which the stator and / or the rotor comprises at least one groove configured to at least partially accommodate the rotary valve flat seal. There are several advantages to such a groove. For example, a such a groove makes it possible to fix the position of the rotary valve flat seal with respect to the rotor and / or the stator.

[0028] In a particular embodiment, the stator and / or the rotor comprises at least one groove configured to at least partially accommodate said at least one second elastically deformable seal.

[0029] In a particular embodiment, the stator and / or the rotor comprises at least one groove configured to fully accommodate said at least one second elastically deformable seal.

[0030] Preferably, the elastically deformable seal of the rotary valve flat seal is received at least partially in a groove of the rotor face.

[0031] The advantage of a groove configured to at least partially accommodate said at least one second elastically deformable seal is to be able to increase the exposure of said at least one first lubrication seal, thus making it possible to promote lubrication.

[0032] In a particular embodiment, the stator and / or the rotor comprises at least one groove configured to accommodate: - completely said at least one second elastically deformable seal, and - partially said at least one first lubricating seal.

[0033] Such configurations in which said at least one second elastically deformable seal is partially or totally accommodated in at least one groove allow greater exposure of said at least one first lubrication seal, which thus makes it possible to promote lubrication between the rotor and the stator.

[0034] In a particular embodiment, pressure is exerted on the stator and / or the rotor so as to exert pressure on the rotary valve flat seal and promote the reception of the latter in said at least one groove of said stator and / or rotor.

[0035] Advantageously, the rotor and the stator are held in compression against each other by means of a spring. This promotes, where appropriate, the reception of said rotary valve flat seal in said at least one groove of said stator and / or rotor.

[0036] In a particular embodiment, the rotor is accommodated by a fixed barrel having a leakage opening communicating with the second chamber. In this embodiment, the rotor is in contact with the stator and on the opposite side of the rotor, the latter is accommodated by a fixed barrel. This fixed barrel is distinguished from the stator in that it does not necessarily have a face (in contact with the rotor) with a plurality of openings passing through it as is the case with the stator.

[0037] In a particular embodiment, the lubrication seal is a seal made of a self-lubricating material. The advantage is that the seal and thus the valve gain in operating autonomy and require less maintenance than with a seal without self-lubricating material.

[0038] Advantageously, the lubricating seal comprises PTFE and / or graphite.

[0039] Preferably, the lubrication seal comprises PTFE. The configuration of the lubrication seal makes it possible to incorporate PTFE in a minimal quantity, but sufficient to ensure self-lubrication.

[0040] Preferably, the elastically deformable seal has a toric cross-section. The toric section will have the advantage of being able to deform relatively easily by matching the surface of the rotor or stator on which it is in contact and said at least one first lubricating seal. Furthermore, in the case where the elastically deformable seal is received in a groove, such an toric seal allows effective anchoring of the seal in said groove.

[0041] Advantageously, the pressurizing opening is placed along the axis of rotation of the rotor. Thus, the opening can be configured to always be supplied with pressurized fluid.

[0042] In a particular embodiment, the rotary valve flat seal delimits at least one third chamber on the rotor face configured to allow pressure equalization between said at least two openings of the stator which coincide with said at least one third chamber. Thus, a pressure equalization chamber between at least two openings of the stator.

[0043] Advantageously, the plurality of openings passing through said stator form channels having at least one bend. Thus, the stator has a fluid communication means (a channel) which is not necessarily parallel to the axis of rotation of the rotor, given that the rotary valve plane seal is limited to the stator-rotor contacting interface with this particular rotary valve.

[0044] In addition and advantageously, the oxygen compressor is oil-free. An advantage is that it limits maintenance of the compressor.

[0045] In a particular embodiment, the connection line is provided with at least one outlet for discharging the oxygen produced. An outlet can, for example, make it possible to place the oxygen produced in an external tank, for example, or in the event of overpressure to have an escape of the oxygen at a particular point and thus better control the risks associated with the use of oxygen.

[0046] Advantageously, the air and oxygen compressors are housed at least partially inside a frame. Thus, by isolating the air and oxygen compressors in a frame, the frame preferably being transportable, it is possible to move the assembly in order to position it, for example, in a building such as a hospital.

[0047] In a particular embodiment, the oxygen compressor is arranged in the upper part of the frame. Thus, such an arrangement allows thermal dispersion made easier. In fact, since heat rises naturally, insulating the compressor is easier to achieve and the other elements contained in the frame are less exposed to this heat.

[0048] Preferably, the cabinet-shaped frame has a width of at most 2 meters and a height of at most 3 meters, preferably the width and / or the height being configured to allow a door to pass through. More preferably, the cabinet-shaped frame has a width of at most 1 meter and a height of at most 2 meters. Thus, such frames are relatively easy to install in buildings, without having to dismantle parts of this building (such as partitions and / or doors).

[0049] In a particular embodiment, the frame is a rolling frame. Thus, it is easy to move the frame without additional moving tools, for example in a reception building.

[0050] FIGURES

[0051] Embodiments of the present invention will be described below, by way of non-limiting examples, with reference to the appended figures in which:

[0052] [Fig.l] [Fig.l] is a schematic view of an embodiment of the installation according to the present invention employing in particular twelve tanks.

[0053] [Fig.2] [Fig.2] is a schematic view of an embodiment of the installation according to the present invention employing a rotary valve 10 (the fluid paths in the valve of which are detailed) with 6 reservoirs.

[0054] [Fig.3] [Fig.3] is a schematic view of an embodiment of the installation according to the present invention integrating optional structural elements.

[0055] [Fig.4] [Fig.4] is a sectional view of a frame incorporating an embodiment of the installation according to the present invention.

[0056] [Fig.5] [Fig.5] is a schematic view of another embodiment of the installation according to the present invention employing in particular twelve tanks.

[0057] With reference to [Fig.l], the installation shown comprises a compressed air source 9 supplying a rotary valve 10 and twelve reservoirs 5.

[0058] The reservoirs 5 each comprise a first end 7, a body 6 and a second end 8.

[0059] The rotary valve 10 supplies the twelve reservoirs 5 via their first end 7.

[0060] The second end 8 of each tank 5 opens into a line 16 for connecting the second ends 8 of the tanks 5 to each other by a connecting interface 17.

[0061] This connection interface 17 defines two parallel pipes 18 on at least one part of their length and each connecting the second end 8 of the tank 5 and the connection line 16 between them.

[0062] Each pipe 18 has a non-return valve 20, the non-return valves 20 being reversed from one pipe to another.

[0063] Furthermore, each pipe 18 has at least one flow regulator 19 arranged in series with said non-return valve 20.

[0064] The connection line 16 is provided with at least one outlet 21 for evacuating the oxygen produced.

[0065] [Fig.2] represents a particular embodiment of the installation according to the present invention, in which a rotary valve is configured to allow both pressurization of two tanks 5, depressurization of two tanks 5 and equalization of two other tanks 5, i.e. an installation comprising six coupled tanks.

[0066] The rotary valve is supplied with air, for example in the same manner as shown in [Fig.l] (via a compressed air source 9).

[0067] Each tank 5 is then connected, downstream in the same way as in [Fig.l], that is to say via the second end 8 of each tank 5 opening into a line 16 for connecting the second ends 8 of the tanks 5 to each other by a connecting interface 17.

[0068] In the same way as in [Fig.l], this connecting interface 17 defines two parallel pipes 18 over at least part of their length and each connecting the second end 8 of the tank 5 and the connecting line 16 between them.

[0069] In the same way as in [Fig.l], each pipe 18 has a non-return valve 20, the non-return valves 20 being reversed from one pipe to another.

[0070] Furthermore and in the same manner as in [Fig.l], each pipe 18 has at least one flow regulator 19 arranged in series with said non-return valve 20.

[0071] In the same way as in [Fig.l], the connection line 16 is provided with at least one outlet 21 for evacuating the oxygen produced.

[0072] [Fig. 3] represents an installation 1, according to the present invention, comprising an air compressor 2, coupled to a heat exchanger 14 (cooled for example by a fan driven by a first motor M).

[0073] An oxygen generator 3 supplies a buffer tank 12 (for example with an internal pressure measuring means PT), which is coupled to an oxygen compressor 4.

[0074] This oxygen compressor 4 has a conduit, configured in one direction, for example thanks to a valve possibly also connected to a solenoid valve EV, supplying a second heat exchanger 14.

[0075] An extraction device A, as shown in [Fig.l] or in [Fig.2], is integrated into the assembly to produce pure oxygen which is then stored in an oxygen tank 13 which, in turn, feeds a network, for example a hospital oxygen network.

[0076] Optionally, a frame 11 accommodates these different elements (preferably the oxygen tank 13 is placed outside the frame).

[0077] [Fig.4] shows a frame 11, comprising an oxygen generator 3, an oxygen compressor 4, an air compressor 2, a rotary valve 10 and a drying device 22.

[0078] The air compressor 2 and the oxygen compressor 4 are placed on the upper part of the frame in order to improve the thermal insulation of the other components of this frame placed below these two compressors.

[0079] With reference to [Fig.5], the installation shown, of a design very close to the installation according to [Fig.1], comprises a source of compressed air 9 supplying a rotary valve 10 according to the present invention and twelve reservoirs 5.

[0080] Thus, the embodiment as shown in [Fig.l] presents an optimized installation allowing an adjustable variation of the flow rate according to the direction of the fluid downstream of the reservoirs 5, as described below.

[0081] The reservoirs 5 each comprise a first end 7, a body 6 and two second (outlet) ends 8.

[0082] The rotary valve 10 supplies the twelve reservoirs 5 via their first end 7.

[0083] The second ends 8 of each tank 5 open into a line 16 for connecting the second ends 8 of the tanks 5 to each other by a connecting interface 17A.

[0084] This connecting interface 17A defines two parallel pipes 18 over at least part of their length and each connecting the two second ends 8 of the tank 5 and the connecting line 16 between them.

[0085] Each pipe 18 has a non-return valve 20, the non-return valves 20 being reversed from one pipe to another.

[0086] Furthermore, each pipe 18 has at least one flow regulator 19 arranged in series with said non-return valve 20.

[0087] The connection line 16 is provided with at least one outlet 21 for evacuating the oxygen produced.

[0088] This installation with the interface 17A as shown makes it possible to control the fluid flows downstream of the reservoirs 5, which allows for production optimization, particularly in terms of consistency of the flow rate of fluid produced.

[0089] For reasons of ease of implementation of such an installation, it can be incorporated, at least partially, in a frame (not shown in [Fig.5]) configured to be moved and installed easily in a room of limited size (such than a hospital room or a dedicated technical room).

[0090] Thus the installation according to [Fig.5] has valves 20 arranged in parallel instead of being in series as in [Fig.l].

Claims

Claims

1. Installation for the production of oxygen, said installation comprising at least one air compressor (2), one oxygen generator (3) and one oxygen compressor (4), said oxygen generator (3) applying the so-called PSA technology comprising tanks (5), each tank (5) having two ends (7, 8) and a body (6) at least partially filled with a molecular sieve (adsorbent), open at each of its ends (7, 8) to define between said ends (7, 8) a flow path through the molecular sieve, one of the ends (7, 8) called the first end (7) of each tank (5) being selectively connectable to a source (9) of pressurized or exhausted air to allow a pressurization / depressurization cycle of said tank (5),each molecular sieve being capable of adsorbing nitrogen molecules and allowing oxygen to pass through under the effect of pressurization of the tank (5) and releasing the nitrogen molecules by desorption under the effect of exhausting the tank (5), in which the installation (1) comprises, for the pressurization / depression of the tanks (5) or at least part of the tanks (5) a rotary valve (10) common to said tanks (5), this rotary valve (10) interposed between the first end (7) of each tank (5) and at least one source (9) of compressed air having for each tank (5) to which it is connected at least two angular positions corresponding one, called the pressurization position, to a position for supplying pressurized air to said tank (5), another, called the depressurization position, to a position for exhausting said tank (5),characterized in that the second end (8) of each tank (5) opens into a line (16) for connecting the second ends (8) of the tanks (5) to each other by a connecting interface (17), this connecting interface (17) defining two parallel pipes (18) over at least part of their length and each connecting the second end (8) of the tank (5) and the connecting line (16) to each other, each pipe (18) has a non-return valve (20), the non-return valves (20) being reversed from one pipe to another.,

2. Installation according to claim 1, characterized in that each pipe (18) has at least one flow regulator (19) arranged in series with said non-return valve (20).

3. Installation according to claim 1 or 2, characterized in that the first end (7) of each tank (5) is furthermore selectively connectable to another tank (5) to allow an equalization phase in the pressurization / depression cycle and in that the rotary valve (10) has for each tank (5) to which it is connected in addition to the pressurization and depressurization positions an equalization position corresponding to a position of connection of the tank (5) to another tank (5).

4. Installation according to any one of claims 1 to 3, characterized in that the valve (10) is configured to, in at least one angular position, occupy a position corresponding for one of the tanks (5) to the pressurization position of said tank (5) and for the other or another of the tanks (5) to the position corresponding to the depressurization position of said tank (5).

5. Installation according to any one of claims 1 to 4, characterized in that at least one of the angular positions of the valve (10) corresponds, for a first tank (5) or a first series of tanks (5), to a pressurization position of said first tank (5) or of the first series of tanks (5), for a second tank (5) or a second series of tanks (5), to a depressurization position of said second tank (5) or of the second series of tanks (5), and for the third tank (5) or the third series of tanks (5) to an equalization position of said third tank (5) or of the third series of tanks (5).

6. Installation according to any one of claims 1 to 5, characterized in that the oxygen compressor (4) is oil-free.

7. Installation according to any one of claims 1 to 6, characterized in that the connection line (16) is provided with at least one outlet (21) for evacuating the oxygen produced.

8. Installation according to any one of claims 1 to 7, characterized in that the air (2) and oxygen (4) compressors are housed at least partially inside a frame (11)

9. Installation according to claim 8, characterized in that the oxygen compressor (4) is arranged in the upper part of the frame (11).

10. Installation according to claims 8 or 9, characterized in that the frame (11), in the form of a cabinet, has a width at most equal to 2 meters and a height at most equal to 3 meters, preferably the width and / or height being configured to allow passage through a door.

11. Installation according to any one of claims 8 to 10, characterized in that the frame (11) is a rolling frame (11).

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