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
  • B01D53/025—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 wetted adsorbents; Chromatography
• • 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
  • B01D2257/00—Components to be removed
  • B01D2257/50—Carbon oxides
  • B01D2257/504—Carbon dioxide
• • 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 process for separating gaseous CO 2 contained in a gas mixture.
• US Pat. No. 2,823,765 discloses a process for separating gaseous mixture containing one or more gases that can be adsorbed by an adsorbent. This method comprises contacting the gas mixture with an adsorbent suspended in a liquid at high pressure.
• the adsorbent is incompatible with the liquid and is in particular activated carbon; carbon dioxide is mentioned as a gas to which the process can be applied.
• the present invention aims to overcome the disadvantages of known techniques, by providing an efficient and low cost method for the separation of gaseous CO 2 contained in a gaseous mixture.
• the subject of the present invention is a process for separating gaseous CO 2 contained in a gas mixture comprising: a step of suspending in a liquid phase an absorbent solid capable of capturing the gaseous CO 2 , and
• a step of dispersing the gas mixture in the liquid phase said step being carried out at a temperature between the solidification temperature and the vaporization temperature of the liquid phase, excluding the limits, and at a pressure comprised between atmospheric pressure and 10 bars, terminals included.
• the invention is based on the surprising finding, verified experimentally by the inventors, that, during the dispersion of a gas mixture in a liquid phase, the amount of CO 2 trapped by an absorbent solid suspended in a liquid phase is much higher than that retained by the same solid in the gas phase.
• the process according to the invention is furthermore particularly advantageous in that it displays a high yield at ambient temperature and pressure conditions, or close to ambient conditions, and therefore is economically very advantageous.
• the dispersion of the solid is carried out: in an aqueous solution; for example pure water or a saline solution,
• an alcohol for example ethanol, propanol, ethylene glycol - or in a ketone; for example, acetone.
• the dispersion of the gas mixture is carried out in the form of bubbles in the liquid.
• the finer the dispersion the better the homogenization and the diffusion of the gases in the liquid.
• the dispersion step is carried out at a temperature of between 0 ° C. and 30 ° C. and at a pressure, inclusive, between atmospheric pressure (Patm) and 3 bars, more preferably between Patm and 1.5. bars, even more preferably between Patm and 1.2 bars (so with a slight overpressure).
• the dispersion is carried out at conditions of ambient temperature and pressure.
• the absorbent solid is indifferently chosen from: a carbonaceous material, such as, for example, an activated carbon or carbon nanotubes; an oxide, for example silicates such as zeolites, clays, mesoporous silicas, manganese oxides, pumice, perlite or diatomite; phosphate or phosphonate; a hydroxide, such as for example Lamellar Double Hydroxides, such as a 3T quintinite or a hydrotalcite.
• a carbonaceous material such as, for example, an activated carbon or carbon nanotubes
• an oxide for example silicates such as zeolites, clays, mesoporous silicas, manganese oxides, pumice, perlite or diatomite
• phosphate or phosphonate phosphate or phosphonate
• a hydroxide such as for example Lamellar Double Hydroxides, such as a 3T quintinite or a hydrotalcite.
• the process comprises an additional step of recovering the gaseous CO 2 captured.
• the combination of the trapping and recovery steps allows CO 2 purification.
• This recovery step preferably comprises a step of lowering the partial pressure of the gas to be trapped introduced into the liquid phase, this step being obtainable either by lowering the partial pressure of CO 2 (in particular by recirculation in the saturated reactor in CO 2 , a gas stream depleted in CO 2 , from a capture reactor in use) or by using a low vacuum at most equal to 0.2 bar with respect to the capture pressure or by stopping the circulation of the gas containing the CO 2 .
• Recovery of captured CO 2 can also be obtained by a step of raising the temperature of the liquid phase, preferably at most 30 ° C. above the temperature at which the capture has been carried out, without bringing the liquid to boiling.
• Figure 1 is a diagram schematically showing the method according to the invention
• Figure 2 is a curve representing, as a function of time, the concentration of CO 2 in the exit gas stream during capture and release phases by activated carbon
• FIG. 3 is a curve representing, as a function of time, the concentration of CO 2 in the exit gas stream during capture and release phases by a material rich in zeolite
• FIG. 4 is a curve representing, as a function of time, the concentration of CO 2 in the exit gas stream during capture and release phases repeated iteratively by a quintinite 3T which is a hydroxide type material Double Lamellar (HDL)
• a quintinite 3T which is a hydroxide type material Double Lamellar (HDL)
• FIG. 5 is a curve representing, as a function of time, the concentration of CO 2 in the exit gas stream during capture phases by a calcium carbonate type material
• FIG. 6 is a curve representing in FIG. a function of time, the concentration of CO 2 in the exit gas stream during capture phases by a diatomite type material.
• the method comprises a first step 2 in which an absorbent solid suitable for trapping CO 2 is suspended in a liquid medium. It comprises a second step 4 in which the gaseous mixture is dispersed in the liquid medium.
• the liquid medium is placed in a reactor comprising an inlet for admitting the gas mixture and an outlet for extracting the uncaptured gas mixture after treatment or carbon dioxide after liberation.
• the first two stages 2 and 4 make it possible to trap the CO 2 contained in the gas mixture.
• the method may comprise a third step 6 for recovering CO 2 .
• the release of CO 2 entrapped in the trap material can be obtained by reducing the CO 2 partial pressure at the inlet of the reactor, and / or by raising the temperature of the solid suspension and / or or by lowering the total pressure in the capture reactor.
• the two steps 4 and 6 are repeated iteratively, as indicated by the arrow 8, by opening and closing the reactor gas inlet to produce at the outlet of the reactor, when the gas inlet is closed, pure CO 2 .
• a capture and release test of CO 2 from a stream of an N 2 / CO 2 gas mixture was carried out by a trap formed of activated carbon suspended in an aqueous medium.
• the activated carbon used has a surface area of 1500 m 2 / g
• the initially introduced gas mixture had an initial CO 2 content of 19% by volume which was then raised to 76% by volume.
• the treatment was carried out at a temperature of 15 ° C and at atmospheric pressure.
• the CO 2 content in the reactor outlet mixture is shown in FIG. 2.
• the CO 2 content in the input gas mixture is 19% by volume.
• the CO 2 content in the exit gas increases slowly from 0% at time t 0 to 19% until a time t 1, which indicates capture of CO 2 by the trap, then stabilizes at 19% between t1 and t2, indicating that equilibrium is reached.
• the composition of the input gas mixture is modified by raising the CO 2 content to 76% by volume up to a time t4.
• This modification of the CO 2 content is carried out in the context of a laboratory test. In an industrial process, it is generally not possible to proceed with such a modification of the gas mixture. It can be seen that, as during the period t0-t2, the output CO 2 content increases slowly between t2 and an instant t3, marking a capture of CO 2 , and then stabilizes at 76% by volume from t3 when new balance is achieved.
• the volumes of CO 2 captured at a CO 2 content of 19 and 76% respectively represent 0.5 mole of CO 2 / kg of activated carbon and 0.77 mole of CO 2 / kg of activated carbon.
• the volumes of CO 2 captured for CO 2 levels of 19 and 76% were respectively 0.54 mol CO 2 / kg of zeolite and 2.08 mol CO 2 / kg of zeolite, an total amount of 2.62 moles of CO 2 / kg of zeolite.
• time t5 a release of 2.65 moles of CO 2 / kg of zeolite is observed, which corresponds substantially to the portion collected.
• An additional release of 0.39 mole CO 2 / kg of zeolite is observed when the reactor is heated to a temperature of 60 ° C.
• the 3T quintinite is a material of the type Double Lamellar Hydroxide (HDL).
• the test was carried out with an absorbent solid having a specific surface area of 80 m 2 / g placed in aqueous suspension in a reactor at 30 ° C. and under pressure. atmospheric.
• the input gas is an N 2 / CO 2 mixture, the CO 2 content being 9% by volume.
• the test was carried out with a solid of precipitated calcium carbonate (PCC) type placed in aqueous suspension in a reactor at 15 ° C. and at atmospheric pressure.
• the input gas is a N 2 / CO 2 / CO 2 content in the initially being 16% by volume was then increased to 60%.
• the volumes of CO 2 captured represent respectively
• the test was carried out with a diatomite-type solid placed in an aqueous suspension in a reactor.
• the input gas is a N 2 / CO 2 # the CO 2 content initially being 60% by volume.
• the measurement results are reported in FIG. 6.
• the volume of CO 2 captured represents 1.38 moles of CO 2 per kg of diatomite. As for other solids, it has been shown that a lowering of the CO 2 partial pressure leads to a quantitative release of the CO 2 initially captured.
• each cycle comprising a step of supplying a mixture of gases followed by a step without the addition of CO 2 , even without the addition of a gas mixture, it is possible to extract CO 2 from a gas mixture while purifying it.
• the process may be exploited either to generate a pure CO 2 stream or to generate a gas stream enriched in CO 2 . If a stream of pure CO 2 is sought, the release of the captured gas will be obtained by raising the temperature at most equal to 30 ° C. or lowering the pressure, the supply of the initial gas mixture having been interrupted. If a gaseous stream enriched in CO 2 is sought, while the circulation of the gaseous mixture to be treated is maintained, an increase in the temperature of the suspension at most equal to 30 0 C will be sufficient to release the CO 2 initially captured.
• the Double Lamellar Hydroxydes are particularly effective.
• the quintinite 3T and the hydrotalcite one skilled in the art can advantageously refer to the patent FR 2882549 which describes other examples of HDL and a method of synthesizing such materials.
• the process according to the invention is therefore particularly interesting from an industrial point of view. Indeed, it allows the trapping of CO 2 reversibly without implementing energy-intensive processes

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• Chemical & Material Sciences (AREA)
• Analytical Chemistry (AREA)
• Engineering & Computer Science (AREA)
• General Chemical & Material Sciences (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Solid-Sorbent Or Filter-Aiding Compositions (AREA)
• Treating Waste Gases (AREA)
• Gas Separation By Absorption (AREA)
• Carbon And Carbon Compounds (AREA)

Applications Claiming Priority (2)

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• 2007
  • 2007-01-24 FR FR0700482A patent/FR2911517B1/fr not_active Expired - Fee Related
• 2008
  • 2008-01-24 CN CN200880003110A patent/CN101754793A/zh active Pending
  • 2008-01-24 US US12/524,459 patent/US20100061917A1/en not_active Abandoned
  • 2008-01-24 CA CA002676345A patent/CA2676345A1/fr not_active Abandoned
  • 2008-01-24 JP JP2009546790A patent/JP2010516607A/ja active Pending
  • 2008-01-24 RU RU2009128585/05A patent/RU2009128585A/ru not_active Application Discontinuation
  • 2008-01-24 WO PCT/FR2008/000087 patent/WO2008110676A2/fr active Application Filing
  • 2008-01-24 BR BRPI0807440-2A patent/BRPI0807440A2/pt not_active IP Right Cessation
  • 2008-01-24 EP EP08761801A patent/EP2106283A2/de not_active Withdrawn
  • 2008-01-24 AU AU2008225736A patent/AU2008225736A1/en not_active Abandoned
• 2009
  • 2009-07-21 ZA ZA200905077A patent/ZA200905077B/xx unknown

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