Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
  • B01D53/02—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by adsorption, e.g. preparative gas chromatography
  • B01D53/04—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by adsorption, e.g. preparative gas chromatography with stationary adsorbents
  • B01D53/0407—Constructional details of adsorbing systems
  • B01D53/0446—Means for feeding or distributing gases
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2253/00—Adsorbents used in seperation treatment of gases and vapours
  • B01D2253/10—Inorganic adsorbents
  • B01D2253/102—Carbon
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2253/00—Adsorbents used in seperation treatment of gases and vapours
  • B01D2253/10—Inorganic adsorbents
  • B01D2253/106—Silica or silicates
  • B01D2253/108—Zeolites
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2256/00—Main component in the product gas stream after treatment
  • B01D2256/12—Oxygen
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2257/00—Components to be removed
  • B01D2257/10—Single element gases other than halogens
  • B01D2257/102—Nitrogen
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2257/00—Components to be removed
  • B01D2257/50—Carbon oxides
  • B01D2257/504—Carbon dioxide
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2257/00—Components to be removed
  • B01D2257/80—Water
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2259/00—Type of treatment
  • B01D2259/40—Further details for adsorption processes and devices
  • B01D2259/414—Further details for adsorption processes and devices using different types of adsorbents
  • B01D2259/4141—Further details for adsorption processes and devices using different types of adsorbents within a single bed
  • B01D2259/4145—Further details for adsorption processes and devices using different types of adsorbents within a single bed arranged in series
  • B01D2259/4148—Multiple layers positioned apart from each other
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
  • B01D53/02—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by adsorption, e.g. preparative gas chromatography
  • B01D53/04—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by adsorption, e.g. preparative gas chromatography with stationary adsorbents
  • B01D53/0407—Constructional details of adsorbing systems
  • B01D53/0431—Beds with radial gas flow
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
  • B01D53/26—Drying gases or vapours
  • B01D53/261—Drying gases or vapours by adsorption
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02C—CAPTURE, STORAGE, SEQUESTRATION OR DISPOSAL OF GREENHOUSE GASES [GHG]
  • Y02C20/00—Capture or disposal of greenhouse gases
  • Y02C20/40—Capture or disposal of greenhouse gases of CO2

Definitions

• the present invention relates to a method of separating components of a gas by adsorption.
• Current state of the art
• the cryogenic technique is applied for very high quantities of gas to be treated. These are high-tech centralized installations due to the extremely low temperatures to be reached in order to obtain the liquefaction necessary for the separation of the components from the gas to be treated.
• the cryogenic technique has the significant drawbacks of having many exchangers and devices operating at very low temperatures (-100 to -190 ° C) and of consuming a great deal of energy.
• This type of process is costly in investment: to obtain a sufficient return, it is necessary to build very large centralized units in order to benefit from the "size effect" and it is necessary to deliver the pure gas to the users by means of a wide network of canalisa- tions, or by transporting this gas in liquid form and this requires very expensive specific means.
• This known PSA process comprises (FIG. 1) two or more reactors A and B filled with adsorbent mass, a gas compressor 15 which supplies the reactor A with gas after cooling in an exchanger 106 by opening the valve 101.
• the gas to be separated into its components passes through the reactor A, the adsorbent material being chosen to preferentially retain one or more components of the air (H20, N2 for example).
• the gas gradually depletes these components until they are almost completely eliminated.
• the chosen component oxygen for example
• the components not chosen are adsorbed and accumulate in the adsorbent mass which is rapidly saturated. It is therefore necessary to regenerate the adsorbent. To avoid stopping production during regeneration, a second or more reactors operating alternately or substantially simultaneously are required. While the component to be extracted (N2 for example) is adsorbed in reactor A, the same adsorbed component is desorbed in the mass of reactor B. To this end, reactor B isolated from the reactor A by closing of valves 111 and 113 is subjected to a pressure drop when opening a valve 112, LEMENT the adsorbed gas being extracted by a vacuum created by the vacuum pump 6. The adsorbed gas is thus progressively evacuated from the adsorbent mass by the effect of pressure change.
• the adsorbent mass of the reactor A is saturated and that of the reactor B is regenerated, and the gas circuits are inverted.
• the fresh gas is sent to reactor B and the desorption is carried out in reactor A by reversing the valves 101, 102, 111, ' 112, 103, 113.
• the residual gases contained in the gases are evacuated reactors, by reverse sweeping of pure gas (oxygen for example) by means of valves 104 and 114.
• the known PSA process described above although of fairly recent development, has the drawback of comprising a large number of operating valves very frequent, i.e. 500,000 operations per year. This requires the use of very high quality materials and an efficient maintenance service. The high number of reversal operations imposes a limit diameter of the valves, and consequently a limited gas treatment capacity.
• energy consumption although lower compared to the cryogenic technique, is still very high.
• Patent application EP-A-0 512 534 filed on 07.05.92 describes a P.S.A. system. composed of a fixed or mobile reactor, divided into compartments (2 to 8) and fed by one or two horizontal rotary flat valves rotating between fixed plates.
• the present invention aims to remedy the drawbacks of the techniques, methods and systems described above and to provide a process which is particularly economical, both in terms of investment and consumption, and which makes it possible to use separation equipment.
• gas of any size from 50 to 20,000 ⁇ v '/ h of oxygen production for example
• valves devices with high wear intensity
• the separation method according to the invention consists, in an enclosure divided into the same separate, sealed compartments which are each lined with an adsorbent material chosen as a function of the gas to be treated and which are each arranged to temporarily allow the admission of the gas to be sorted and the evacuation of at least one of the selected components of this gas while the other component (s) are adsorbed by the aforementioned material, to admit the gas to be treated in one of the compartments until a determined pressure is reached while in the following compartments and in order, from the one closest to said compartment where the gas is pressurized, the operations are carried out following: one admits, in at least one compartment, of the gas to be treated and one authorizes the escape therefrom of the aforementioned chosen component, one lets, in the following compartment, drop the pressure to proceed natu actually a partial desorption of the non-selected components of the gas, a rinsing fluid is injected into the last compartment to ensure the final desorption of the aforementioned material.
• At least one additional compartment is provided, between the compartment where the pressure is allowed to drop and the compartment where the rinsing fluid is injected, in which a vacuum is created.
• an additional compartment is provided, between the compartment in which there is a vacuum and the compartment in which the gas to be treated is placed ⁇ : ⁇ pressure, in which naturally accepts the gas to be treated.
• ⁇ pressure in which naturally accepts the gas to be treated.
• the energy produced by the above-mentioned pressure drop is recovered.
• the invention also relates to a device for implementing the above method.
• this device comprises similar compartments, with double bottom, which are separate, sealed and each lined with at least one same adsorbent material resting on the upper bottom and which are each provided with two orifices made in a wall of the compartment and selectively intended for the passage of the gas to be treated, its components and the rinsing fluid, one of the orifices being disposed between the two bottoms and the other at the level of the material adsorbed, a passage being provided in the upper bottom and communicating with a space in the same compartment situated opposite the aforesaid orifices and delimited by a grid extending transversely to the upper bottom, a second grid being arranged substantially parallel to the wall having the two aforementioned orifices and being arranged close to the latter in the compartment, the adsorbent material being held between these two grids, said compartments being fixed and regularly distributed around distribution means comprising a distributor cylinder arranged to be able to rotate around its axis in order to cooperate in turn tower with the afore
• FIG. 1 schematically represents the system for implementing the P. S.A. method as described above.
• Figure 2 is a schematic representation in elevation and in axial section, along line II-II of Figure 3, of a device according to the invention- tion for the implementation of the process according to the invention.
• FIG. 3 shows a cross section of said device at the location of line III-III of FIG. 2.
• FIGS. 4 to 11 each show a cross section of said device at the location of the respective lines IV-IV to XI-XI of FIG. 2.
• FIG. 12 shows in section and in elevation, with broken lines, an enlarged detail of FIG. 2, in order to explain an arrangement of O-ring seals.
• Figures 13 and 14 each show in elevation and in development, with broken lines, an enlarged detail of Figure 2, seen according to arrows respec ⁇ tive XIII or XIV, on the periphery of the distributor cylinder.
• the method and its implementation device according to the invention are characterized inter alia by the continuity of operation, by the absence of means for opening and closing the passage of gases comprising organs requiring maintenance such as usual valves, and by the possibility of producing units of any size (50 to 20,000 m 3 / h of oxygen for example), leading to an ever lower production cost.
• the method and its implementation device according to the invention can be used in multiple applications indicated below without limitation: production of industrial or medical oxygen or nitrogen from ambient air (depending on the nature of the adsorbent), separation of carbon dioxide from natural gas, production of pure hydrogen from hydrogenated gas.
• the gas separation process according to the invention is based on the preferential adsorption of the components of the gas on adsorbent and it works by periodically changing the pressure to ensure the various phases required, ie : - pressurization, adsorption and emission of pure gas, decompression and partial desorption, preferably with energy recovery, vacuum and final desorption, - vacuum recovery, possibly with energy recovery.
• the device 100 for implementing the method of the invention is made up of a fixed closed cylindrical or polygonal envelope 1 which is the enclosure 1 of the adsorption reactor comprising an internal cylindrical duct 2 provided with gas passage openings 3 and 4 (preferably one of each per compartment).
• a rotary tubular distributor or distributor cylinder 5 supplies the enclosure 1 with raw gas and makes it possible to evacuate the desorbed gas during decompression by vacuum and possibly by vacuum produced by vacuum pump 6, 66.
• the enclosure is divided into compartments 27 having the form of sectors of a circle or of a polygon 27 in cross section, represented in FIG. 3 and separated from each other by vertical, waterproof walls 28.
• Each compartment 27 is filled with at least one adsorbent material suitable for the nature of the gas to be extracted: a desiccant 7 and / or a zeolite 8 by example, or even other specific adsorption masses. Different adsorbent materials 7, 8 are preferably separated by one or more grids (9).
• each compartment 27 is provided with an inlet opening 3 for raw gas, this opening 3 also being intended for discharging the gas during desorp ⁇ tion from the mass by the effect of pressure drop.
• a sheet 10 fixed on the same wall 2 inside the enclosure 1 forms with the bottom 99 of the enclosure 1 a double bottom and makes it possible to direct the passage of the incoming raw gas (arrow 98) or the desorbed gas outgoing (arrow 97) from the compartments 27 towards, or coming from the internal periphery of the enclosure 1, in order to ensure a radial passage of the gases not only between this double bottom between 10 and 99 but especially through the mass or masses 7, 8 (arrow 96 during absorption and 95 during desorption).
• this sheet 10 On this sheet 10 are fixed grids 11, 9, 12 for the peripheral distribution of the gases and for retaining the adsorbent masses 7, 8 without mixing them.
• a first adsorbent mass intended to adsorb a first set of gas components, a desiccant for example, is represented by 7 and is placed between the grids 11 and 9.
• a second adsorbent material intended to specifically adsorb a second component of the gas is shown in 8 (special zeolite or activated carbon for example) and is placed between the grids 9 and 12. It is also possible to provide at least a third type of specific adsorbent mass for extract a third component from the gas, this is not shown in the figures.
• the same wall 2 of the enclosure 1 is provided with evacuation orifices 4 for the purified gas, or component selected, arranged on the internal cylinder 2. The opening and closing of these orifices is controlled by the rotary distributor 5.
• the rotary distributor 5 is intended to transfer the gases into the various appropriate compartments 27, either the raw gas or the desorbed gases extracted from the adsorbent masses 7, 8, or the purified gas.
• This distributor is also a means of transferring the various gases coming from or to the external connections, for example a raw gas blower 15, energy recovery turbines 16, one or more vacuum pumps 6, 66.
• the rotary distributor 5 is provided with ports 33, 34 intended for the flow of gases and located inside the enclosure 1 and others located outside the enclosure 1 for the routing gas exté ⁇ (see Figure 2 and Figures 4 to 11).
• the rotary distributor 5 is also provided with gas flow channels a, b, c, d, e, f, (FIGS. 3 and 4 to 11) formed along the axis of the distributor 5 and ensuring the selective passage of the gas to their destination.
• the rotary cylindrical distributor 5 is provided with O-rings 13 and with sealing segments 14 shown in FIGS. 2 and 12 to 1.
• the gas leaks are thus eliminated both in the enclosure 1 and in the external part of the above distribution means connected to the outside, and this despite the play existing between the internal fixed cylinder 2 and the rotary distributor 5 .
• the rotary distributor 5 is driven in a rotational movement, at adjustable speed, for example between 0.2 and 5 revolutions / minute, by means of an electric or pneumatic motor 23 according to a continuous or sequential mode of rotation (not step by step).
• the system described above can be simplified by reducing the number of compartments, i.e.
• the fan 15 is driven by an electric motor 80 to the shaft of which the energy recovery turbine 16A is also coupled.
• vacuum pumps 6, 66 are driven for example by an electric motor 81 to the shaft of which the energy recovery turbine 16B can be coupled. Operation of the method and device according to the invention.
• the raw gas (air for example) is brought under pressure and at ambient temperature from the blower 15 to the base of the reactor 1 where it accesses the rotary distributor 5 via the orifices 17 (FIG. 2) and the internal channel a (FIG. 3 and Figure 6).
• the raw gas is distributed in a number of compartments 27, four for example through the orifices provided in the distributor 5 (orifices 33 in Figures 2 and 5).
• the raw gas is oriented inside the compartments 27 in the adsorption phase thanks to the plate
• the gas is distributed in a first adsorbent mass 7 ((drying for example) by means of a grid 11 radially from the outside to the inside of the reactor. tor (arrows 96) and the gas gets rid of a first component (humidity for example) then it passes through a special adsorbent mass 8 (zeolite or activated carbon), going towards the axis of the reactor 1.
• adsorbent mass 8 zeolite or activated carbon
• the gas thus purified (oxygen for example) is collected in the central part of the reactor 1 between the grid 12 and the inner fixed cylinder 2. It is directed towards the other end of the reactor, for example upwards, through the orifices 4 and the openings 44 uncovered of the rotary distributor 5 (see section of FIG. 4) and situated to the right of the channel a (FIG. 3) but opening into a channel g leading to the outlet of the enclosure 1, along arrow 94 (the channel g being separated from the other channels by a watertight radial partition 50).
• the pure gas is thus evacuated outside the enclosure 1 (at 93) and transferred to use. It should be noted that when four compartments 27 are connected at the same time to the channel a for their pressurization with the gas to be treated (orifices 17, FIG. 6), only three of these compartments 27 are connected to the channel g ( orifices 44a, FIG. 4), the remaining compartment 27 being first pressurized without the possibility of escaping the chosen gas or component. Multiple role of the rotary distributor 5
• compartment 27 is decomorimated to atmospheric pressure by channel b, Figures 3 and 7 (port 18).
• a next compartment 27 is placed under partial vacuum by the channel c (orifice 19, FIG. 8).
• a next compartment 27 is placed under final vacuum by the channel d, Figures 3 and 9 (orifice 20).
• a following compartment 27 is maintained under vacuum and swept by a stream of gas or of pure component chosen to eliminate any trace of absorbed gas, via the channel e, FIGS. 3 and 10 (orifice 21).
• the gases thus desorbed are discharged into the atmosphere in the distributor 5, through various orifices 18, 19, 20, 21 in FIG. 2 and in FIGS. 4 to 11 and by the energy recovery machines 16 (A and B) or the pumps empty 6, 66.
• a last compartment 27, previously under vacuum, can be naturally filled with atmospheric raw gas via the channel f (FIG. 3) and the orifice 22 (FIGS. 2 and 11).
• This circuit can be provided with an energy recovery turbine 16B actuated by the natural flow of this gas.
• the central rotary distributor 5, therefore allows each compartment 27 to carry out separately and successively each of the operations required by the method, ie admission of raw gas (orifice 22, channel f) uncompressed with recovery of energy by the ecou ⁇ Lement filling the vacuum prevailing in the corresponding compartment 27, compression (by the orifices 17, channel a), absorption of gas and production of pure gas (leaving by the orifices 44, channel g), partial decompression and recovery of the energy of gas absorbed under pressure (via orifice 18, channel b),
• the speed of rotation of the rotary distributor 5 is adjustable, from 0.2 to 5 revolutions / minute, either according to a continuous rhythm, or step by step and allows the process to be optimized by its gas production capacity, by the quality of the pure gas, by the quantity of absorbent mass, etc.
• the adsorption period of a compartment 27 is short-lived: 10 seconds to 1 minute.
• the distributor 5 having made a rotational movement, the supply of raw gas and the evacuation of pure gas are interrupted by closing the orifices 3 in communication with the sector a of the distributor 5 (FIG. 3) and the orifice 4.
• the compartment is then decompressed via the channel b (FIG. 3) of the distributor 5 and there is partial desorption, the gas being evacuated to the atmosphere via the orifice 18 (FIG. 2), possibly passing through a energy recovery turbine 16 ( Figure 2).
• the vacuum is carried out in one or two stages via the orifices 3, the channels c, d, of the distributor 5 (FIG. 3) of the orifices 19, 20 ( Figure 2) and vacuum pumps 6 and 66. In this operation, all the adsorbed gas
• the total adsorbed gas is then removed by purging with pure gas, by injection of this gas via orifice 4 (figure 2) and the calibrated purge orifice 44b of the distributor 5 ( Figures 2 and 4), the compartment 27 being purged, its orifice 3 ( Figure 2) the channel e of the distributor ( Figure 3) the orifice 21 ( Figures 2 and 10), the vacuum pump 66.
• an expansion turbine 16 (figure 2) which recovers the decompression energy and one can split the vacuum level into two or more circuits and vacuum pumps 6, 66 ( Figure 2).
• the vacuum energy is recovered by incorporating raw gas (atmospheric air for example) via the orifice 22 of the rotary distributor 5, the channel f ( Figures 3 and 11) and ori ⁇ fice 3. This operation saves an amount of raw gas that must be compressed otherwise.
• the flow rates of the gases passing through the absorption masses 7, 8 are progressively reduced as the absorption reaction progresses, for example: 10 m 3 of raw air at the inlet, 1 m 3 d pure oxygen at the outlet.
• the device may comprise only one enclosure 1 of simple construction; in addition, it does not include equipment in devices with frequent operations and susceptible to wear (unlike the valves of the known PSA units described above).
• the process according to the invention and its technical implementation have characteristics making it possible to manufacture gas separators of any capacity, for example 50 to 20,000 m J / h.
• a device may be able to operate in a flow range from 1 to 6 by adjusting the speed of rotation of the distributor 5.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Analytical Chemistry (AREA)
• General Chemical & Material Sciences (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Separation Of Gases By Adsorption (AREA)

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• 1992
  • 1992-08-18 LU LU88160A patent/LU88160A1/fr unknown
• 1993
  • 1993-08-18 AU AU49365/93A patent/AU4936593A/en not_active Abandoned
  • 1993-08-18 WO PCT/BE1993/000053 patent/WO1994004249A1/fr not_active Application Discontinuation
  • 1993-08-18 EP EP93918807A patent/EP0655941A1/de not_active Withdrawn
  • 1993-08-18 US US08/387,747 patent/US5632804A/en not_active Expired - Fee Related

Non-Patent Citations (1)

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