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
  • B01D2257/00—Components to be removed
  • B01D2257/30—Sulfur compounds
  • B01D2257/302—Sulfur oxides
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2257/00—Components to be removed
  • B01D2257/40—Nitrogen compounds
  • B01D2257/404—Nitrogen oxides other than dinitrogen oxide
• • 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 method of separation and / or purification of gas mixtures, some of which are able to form anionic species in aqueous phase.
• traps consist in particular of zeolites or active carbons.
• a problem of this technique is however to require the implementation of high temperatures and high pressures that are necessary for the formation of the capillary condensation phenomenon.
• the present invention uses, in order to ensure the separation / purification of a gas mixture, lamellar double hydroxides or amorphous reputed mixed oxides resulting from a moderate heat treatment of HDL which are either of natural origin , of origin of synthesis. It is known in fact that these compounds, which have many similarities with the anionic clays, have, like them: a structure in sheets, sheets filled by isomorphic substitutions, exchangeable ions compensating for charge deficits.
• the double lamellar hydroxides, or HDL which are of a relative rarity in nature can be manufactured by synthesis, as explained in the French patent application FR 05 01948 filed by the applicant company.
• an aqueous phase synthesis of compounds of the double lamellar hydroxide type is carried out starting from precursor elements, at least partly solid, and this using as precursors elements natural minerals or industrial by-products. , by performing at least partial solubilization of these precursor elements, so as to obtain a solution of divalent and trivalent cations and by performing a co-precipitation with a base of this cation solution.
• double lamellar hydroxide type compounds are directly related to their structure and their ability to integrate in this structure a multitude of divalent and trivalent cations, but also some cations monovalent (such as for example Li + ) and tetravalent (such as Sn 4+ ).
• the lamellar double hydroxides are also capable of adsorbing, in interlamellar intercalation by ion exchange, a large variety of anions. Such properties are likely to find direct applications in the field of trapping by scavenging heavy metals such as lead, zinc, tin, and anions such as sulphates, arsenates, and chromates.
• the subject of the present invention is thus a method for separating / purifying a mixture (M) of gas, comprising a step of capturing at least one gas capable of generating anionic species by dissolution in an aqueous phase, characterized in that what it comprises the steps of:
• an adsorbent product consisting of a double lamellar hydroxide or of a mixed amorphous mixed oxide resulting from a moderate heat treatment of HDL having an affinity for the anion resulting from the dissolution of the gas at capture,
• the process according to the invention preferably comprises an additional step consisting in treating the adsorbent recovered by thermal means in order to release the gas or gases stored in the adsorbent.
• chemical means such as a saline or dilute acid solution, attacking the adsorbent so as to break its structure or means able to carry out anionic displacement.
• the process may then comprise a step of reconstituting the latter, in particular consisting of a treatment in a basic medium or a heat treatment.
• the process may comprise steps of capturing at least two gases and treating the recovered adsorbent so as to selectively release at least one gas upon desorption.
• the adsorbent product may also be chosen according to its affinity with the anions of the said gas that it is desired to capture inside the adsorbent.
• One of the particularly interesting advantages of the present invention is that it ensures separation / purification at ambient temperature and at atmospheric pressure. Moreover this method is also interesting insofar as, as explained below, it can be performed at different levels that can combine with each other during the process.
• FIG. 1 is a schematic representation of the implementation principle of the present invention applied to the separation / purification of carbon dioxide.
• FIGS. 2a and 2b are curves respectively representing, as a function of time, the variation of the concentration of carbon dioxide at the outlet of the reactor and the variation of pH inside the liquid phase, during the implementation a process for extracting carbon dioxide from a mixture of nitrogen and carbon dioxide.
• FIG. 3 represents two diffractograms respectively on the curve a) of a mixed oxide resulting from a heat treatment of the double lamellar hydroxides before capture and on the curve b) of the double lamellar hydroxides after capture.
• FIG. 4 is a representative graph of a thermo-gravimetric analysis associated with an analysis of the gases emitted by mass spectrometry of a sample of lamellar double hydroxides containing both sulphate and carbonate anions.
• an adsorbent product consisting of lamellar double hydroxides or a known amorphous mixed oxide resulting from a moderate heat treatment of HDL having the particularity of having an affinity for the anions of the carbon dioxide.
• the adsorbent product is thus suspended in an aqueous phase and the gas mixture M is bubbled into it. It has then been found that the carbonate anions C0 3 2 ⁇ of the carbon dioxide which have passed into solution take place. between platelets of lamellar double hydroxides because of their high affinity with them.
• the adsorbent that is to say the double-layered hydroxides thus charged, is then recovered, followed by a treatment allowing their recovery or, more precisely, the recovery of carbon dioxide in the gaseous and pure state.
• This treatment depending on the adsorbents considered, may be a heat-type treatment, chemical or anionic displacement.
• the separation / purification process according to the invention is advantageous insofar as it can be carried out at different levels which can be combined with one another during the process.
• a first level of separation can be realized at the very beginning of the process, at the stage of the phase of dissolution. It is thus possible to fractionate the gaseous mixture M by varying the solubility difference of the different gases that constitute it in the aqueous phase.
• a second level it is also possible to carry out a selection by varying the affinity difference for the adsorbent product, namely the double-layered hydroxide or a known amorphous mixed oxide resulting from a moderate heat treatment of the HDLs of the various anions of the different gases which are solubilized in the aqueous phase. This anionic selectivity may be modulated depending on the cationic composition of the adsorbent product.
• a selection can be made at the end of the process by selectively controlling the release of the adsorbates during the regeneration of the adsorbents.
• the extraction and purification of a particular gas belonging to the gas mixture M can be carried out in two main ways ie either by trapping in the product adsorbing the gas that it is desired to extract of the mixture and then desorbing it, optionally selectively, or, conversely, by trapping in the adsorbent product the undesirable gas species, leaving then the gas that is to be extracted in the released state.
• FIG. 2a shows the variation as a function of time of the concentration of carbon dioxide in the gaseous flow at the outlet of the reactor. It is found that during the first five hours, which corresponds to the time during which the adsorbent product captures CO 3 2 " carbonate ions, the concentration of carbon dioxide falls to a value of less than 10% of its initial concentration, then to rise again after Once the adsorbent product is saturated with anions, during the initial phase (capture), as shown in Figure 2b, the pH value rises sharply which corresponds to an increase in the basic character of the solution in accordance with the decrease in carbonate ions CO 3 2- in the liquid phase.
• the curve a) represents amorphous mixed oxides resulting from the heat treatment of the double lamellar hydroxides before the entrapment
• the curve b) represents the characteristic curve of the crystallized double lamellar hydroxides resulting from the entrapment.
• the desorption of the adsorbent can also be obtained by carrying out an acid attack thereof which leads to the destruction of its hydroxylated network, thereby causing the salting out of the captured ions.
• An advantage of the process according to the invention is that the adsorbent can then be reconstituted by a treatment in a basic medium or a heat treatment.

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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)
• Treating Waste Gases (AREA)
• Solid-Sorbent Or Filter-Aiding Compositions (AREA)
• Gas Separation By Absorption (AREA)

Applications Claiming Priority (2)

Publications (1)

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Family Applications (1)

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Family Cites Families (11)

• 2005
  • 2005-11-18 FR FR0511687A patent/FR2893516B1/fr not_active Expired - Fee Related
• 2006
  • 2006-11-17 RU RU2008125830/15A patent/RU2008125830A/ru not_active Application Discontinuation
  • 2006-11-17 CN CNA2006800429025A patent/CN101355998A/zh active Pending
  • 2006-11-17 BR BRPI0618703-0A patent/BRPI0618703A2/pt not_active Application Discontinuation
  • 2006-11-17 JP JP2008540655A patent/JP2009515694A/ja active Pending
  • 2006-11-17 US US12/093,715 patent/US20090223366A1/en not_active Abandoned
  • 2006-11-17 WO PCT/FR2006/002534 patent/WO2007057570A1/fr active Application Filing
  • 2006-11-17 AU AU2006314381A patent/AU2006314381A1/en not_active Abandoned
  • 2006-11-17 CA CA002630560A patent/CA2630560A1/fr not_active Abandoned
  • 2006-11-17 EP EP06831131A patent/EP1954375A1/fr not_active Withdrawn
• 2008
  • 2008-05-21 ZA ZA200804399A patent/ZA200804399B/xx unknown

Non-Patent Citations (2)

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