WO2006113674A2 - Membrane conductrice d'ions pour la separation de molecules - Google Patents

Membrane conductrice d'ions pour la separation de molecules Download PDF

Info

Publication number
WO2006113674A2
WO2006113674A2 PCT/US2006/014496 US2006014496W WO2006113674A2 WO 2006113674 A2 WO2006113674 A2 WO 2006113674A2 US 2006014496 W US2006014496 W US 2006014496W WO 2006113674 A2 WO2006113674 A2 WO 2006113674A2
Authority
WO
WIPO (PCT)
Prior art keywords
membrane
phase
carbonate
ions
oxide
Prior art date
Application number
PCT/US2006/014496
Other languages
English (en)
Other versions
WO2006113674A3 (fr
Inventor
Klaus S. Lackner
Alan C. West
Jennifer L. Wade
Original Assignee
The Trustees Of Columbia University In The City Of New York
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by The Trustees Of Columbia University In The City Of New York filed Critical The Trustees Of Columbia University In The City Of New York
Priority to EP06750517A priority Critical patent/EP1879685A2/fr
Publication of WO2006113674A2 publication Critical patent/WO2006113674A2/fr
Publication of WO2006113674A3 publication Critical patent/WO2006113674A3/fr
Priority to US13/052,392 priority patent/US8163065B2/en
Priority to US13/453,300 priority patent/US8435327B2/en

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D71/00—Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
    • B01D71/02—Inorganic material
    • B01D71/024—Oxides
    • 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
    • B01D53/22—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 diffusion
    • B01D53/228—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 diffusion characterised by specific membranes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/38—Liquid-membrane separation
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D67/00—Processes specially adapted for manufacturing semi-permeable membranes for separation processes or apparatus
    • B01D67/0039—Inorganic membrane manufacture
    • B01D67/0041—Inorganic membrane manufacture by agglomeration of particles in the dry state
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D67/00—Processes specially adapted for manufacturing semi-permeable membranes for separation processes or apparatus
    • B01D67/0039—Inorganic membrane manufacture
    • B01D67/0041—Inorganic membrane manufacture by agglomeration of particles in the dry state
    • B01D67/00411—Inorganic membrane manufacture by agglomeration of particles in the dry state by sintering
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
    • B01D69/14—Dynamic membranes
    • B01D69/141—Heterogeneous membranes, e.g. containing dispersed material; Mixed matrix membranes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
    • B01D69/14—Dynamic membranes
    • B01D69/141—Heterogeneous membranes, e.g. containing dispersed material; Mixed matrix membranes
    • B01D69/1411—Heterogeneous membranes, e.g. containing dispersed material; Mixed matrix membranes containing dispersed material in a continuous matrix
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
    • B01D69/14—Dynamic membranes
    • B01D69/141—Heterogeneous membranes, e.g. containing dispersed material; Mixed matrix membranes
    • B01D69/142—Heterogeneous membranes, e.g. containing dispersed material; Mixed matrix membranes with "carriers"
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D71/00—Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
    • B01D71/02—Inorganic material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D71/00—Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
    • B01D71/06—Organic material
    • B01D71/76—Macromolecular material not specifically provided for in a single one of groups B01D71/08 - B01D71/74
    • B01D71/82—Macromolecular material not specifically provided for in a single one of groups B01D71/08 - B01D71/74 characterised by the presence of specified groups, e.g. introduced by chemical after-treatment
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/06—Combination of fuel cells with means for production of reactants or for treatment of residues
    • H01M8/0662—Treatment of gaseous reactants or gaseous residues, e.g. cleaning
    • H01M8/0668—Removal of carbon monoxide or carbon dioxide
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/10—Fuel cells with solid electrolytes
    • H01M8/12—Fuel cells with solid electrolytes operating at high temperature, e.g. with stabilised ZrO2 electrolyte
    • H01M8/124—Fuel cells with solid electrolytes operating at high temperature, e.g. with stabilised ZrO2 electrolyte characterised by the process of manufacturing or by the material of the electrolyte
    • H01M8/1246—Fuel cells with solid electrolytes operating at high temperature, e.g. with stabilised ZrO2 electrolyte characterised by the process of manufacturing or by the material of the electrolyte the electrolyte consisting of oxides
    • 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
    • B01D2323/00—Details relating to membrane preparation
    • B01D2323/15—Use of additives
    • B01D2323/18—Pore-control agents or pore formers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2325/00—Details relating to properties of membranes
    • B01D2325/02—Details relating to pores or porosity of the membranes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2325/00—Details relating to properties of membranes
    • B01D2325/10—Catalysts being present on the surface of the membrane or in the pores
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2325/00—Details relating to properties of membranes
    • B01D2325/26—Electrical properties
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/10—Fuel cells with solid electrolytes
    • H01M8/12—Fuel cells with solid electrolytes operating at high temperature, e.g. with stabilised ZrO2 electrolyte
    • H01M2008/1293—Fuel cells with solid oxide electrolytes
    • 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
    • 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
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/30—Hydrogen technology
    • Y02E60/50—Fuel cells
    • 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
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Definitions

  • the present invention relates to carbon management, and to membranes, systems, and methods for the separation of molecules.
  • Lithium zirconate has recently been investigated as a membrane structure ⁇ see Kawamura, H., et al., Dual-Ion Conducting Lithium Zirconate-Based Membranes for High Temperature CO 2 Separation. Journal of Chemical Engineering of Japan, 2005. 38(5): p. 322-328). However, selectivity of carbon dioxide over other gases was very poor (selectivity of carbon dioxide over methane was about 5).
  • the present invention provides for membranes that can separate one or more types of molecules by transporting ionic species from one side of the membrane to the other side.
  • the membrane allows a neutral molecule to undergo a chemical reaction on one side of the membrane to dissociate into ions, be transported across the membrane as ions, and combine on the other side of the membrane as the neutral molecule.
  • the membrane includes a first phase that form at least one continuous phase from one side of the membrane to another side of the membrane, and a second phase that form at least one continuous phase from one side of the membrane to another side of the membrane.
  • the first phase can conduct a first type of ions and the second phase can conduct a second type of ions.
  • the first phase can conduct carbonate ions and the second phase can conduct oxide ions to separate carbonate dioxide.
  • the present invention also provides membranes for use at high temperatures, e.g., at temperatures from about 200°C and higher, which allows the selective passage of carbon dioxide (CO 2 ).
  • the novel membranes may allow selective passage OfCO 2 as compared to molecular oxygen, nitrogen, carbon monoxide, water, methane, and the like.
  • Carbon dioxide can selectively permeate the membrane encompassed by this invention at temperatures of about 200°C to about 1200°C, or about 400°C to about 1000°C, thus allowing many new technologies to employ the membrane.
  • a bi-continuous membrane conducts a first type of ions, while a second phase conducts a second type of ions.
  • the membrane according to this invention is permeable and selective for one molecular species relative to other molecules.
  • the membrane may contain more than two continuous phases.
  • the membrane may be comprised of three, four, five, or more different and continuous phases.
  • the present invention also relates to a method for producing a membrane for separating a molecular species from other molecules.
  • the method includes tapecasting a suspension that has particles of a first phase and pore formers (particles used to control a porous structure) mixed within a solvent with dissolved binders, plasticizers and other additives into a desired shape to obtain a green body (a term used to denote a roughly held together object).
  • the green body can then be sintered to obtain a porous continuous structure where the porous structure is capable of conducting a first type of ions.
  • the porous structure can then be filled in with a second phase that is capable of conducting a second type of ions to obtain a membrane capable of separating a molecular species from other molecules.
  • the present invention also relates to solid oxide fuel cells capable of operating under substantially steady state conditions.
  • the fuel cells may be driven by a fuel gas containing CO, where the CO 2 membrane of the present invention separates CO 2 from a gas stream containing CO and CO 2 .
  • Figure 1 is a schematic diagram of a carbon dioxide (CO 2 ) separating membrane according to the present invention.
  • Figure 2 is a schematic diagram exhibiting the structure of carbon dioxide (CO 2 ) separating membrane according to the present invention.
  • Figure 3 is a diagram of one exemplary method for fabricating the membrane of the invention using tape casting and dip coating techniques.
  • FIG 4 is a schematic diagram of carbon fueled solid oxide fuel cell (SOFC) utilizing a carbon gasification process and the CO 2 separation membrane of the present invention.
  • SOFC solid oxide fuel cell
  • the present invention relates to membranes, methods, and systems for separating at least one molecule from other molecules through at least two ionically conducting phases.
  • the membrane includes a first phase that form at least one continuous phase from one side of the membrane to another side of the membrane, and a second phase that form at least one continuous phase from one side of the membrane to another side of the membrane.
  • the first phase can conduct a first type of ions and the second phase can conduct a second type of ions.
  • the first type of ions can be conducting from one side of the membrane to the other side in parallel or in opposite directions from the second type of ions.
  • the membrane allows a neutral molecule to undergo a chemical reaction on one side of the membrane and dissociate into ions, allows the ions to be transported across the membrane, and combine on the other side of the membrane as a neutral molecule.
  • the membrane carries a net zero electric current and can be driven by partial pressure differences of the neutral species from one side of the membrane to the other side of the membrane.
  • membranes of the present invention may selectively separate a molecular species from other molecules and have a selectivity that is greater than or equal to 5. In other embodiments, a selectivity of the molecular species to other gases that is greater than or equal to 10, 25, 50, 100, 150, 200 or 500 can be possible.
  • the present invention provides for a bi-continuous membrane that in one phase conducts a first type of ions and a second phase that conducts a second type of ions.
  • a bi-continuous membrane is a membrane having at least two different and distinct continuous phases from one side of the membrane to the other side of the membrane.
  • a bi-continuous membrane is a membrane where there are passageways for two different charges to migrate through two different materials or phases.
  • the two materials or phases can be arranged in such a way that there are continuous paths connecting the two sides of the membrane in both a first phase and a second phase.
  • the present invention provides membranes having a continuous but porous first phase that is solid wherein the pores are filled with a second phase that is molten. In other embodiments, the present invention provides membranes having a continuous but porous first phase that is solid wherein the pores are filled with a second phase that under operating conditions becomes molten. In another embodiments, the present invention provides membranes having a continuous but porous solid first phasea wherein the pores are filled with a solid second phase.
  • the present invention also relates to nano-structured membranes having a porous first phase that is filled with a second phase.
  • the nano-structure membrane can be highly permeable to a molecule to be separated, yet prevent passage of most other materials.
  • the invention provides for custom materials made from dual- ion conducting phases that are mechanically stable in the range of 200 to 1000 0 C (without open cracks or pores) and that prohibits indiscriminate gas flow.
  • the invention provides for membrane materials that have a substantial permeability to a gas to be separated.
  • the invention may allow for the separation of numerous molecules such as, but not limited to, carbon dioxide, sulfur oxides such as sulfur dioxide and sulfur trioxide, nitrates such as ammonium nitrate and potassium nitrate, chlorides such as hydrochloric acid, steam, and the like.
  • a first phase can conduct OH " ions and a second phase can conduct O 2" ions, where the first phase can be a molten hydroxide phase and the second phase can be a solid oxide phase.
  • steam can be transported across a solid electrolyte phase as H ions and as O " ion across a solid oxide phase.
  • H + conductors may be polymer electrolyte membranes such as NAFION membranes and perovskites with large metal ions such as yttria doped BaCeO 3-(1 , SrCeO 3- ⁇ , and BaZrO 3 .a.
  • a first phase can conduct H + ions and a second and third phase can cooperatively conduct Cl " ions, where the first phase can be a solid electrolyte, a polymer electrolyte, or perovskites with metal ions, the second phase can a chloride phase, and the third phase can be an acid.
  • a first phase can conduct NH 4 + ions and a second phase can conduct H + ions, where the first phase can be a molten ammonium phase and the second phase can be a solid electrolyte, a polymer electrolyte, or perovskites with metal ions.
  • a first phase can conduct SO 3 " ions and a second phase can conduct O 2" ions, where the first phase can be a molten sulfite phase and the second phase can be a solid oxide phase.
  • a first phase can conduct SO 2 2" ions and a second phase can conduct O " ions, where the first phase can be a molten hyposulfite phase and the second phase can be a solid oxide phase.
  • a first phase can conduct CO 3 2' ions and a second phase can conduct O 2" ions, where the first phase can be a molten carbonate phase and the second phase can be a solid oxide phase.
  • the invention relates to a membrane comprising a material that absorbs CO 2 on one side and desorbs CO 2 on the other side, hi other embodiments, the membrane can have a substantial and selective CO 2 permeability.
  • the membrane can be selectively permeable for CO 2 over other molecules such as oxygen, nitrogen, carbon monoxide, methane, water, and hydrogen, hi certain embodiments, membranes of the invention may selectively allow permeation of CO 2 and not other gases at temperatures in excess of 200 °C.
  • the membranes of the invention may be stable and have operating temperatures from about 300 °C, 400 0 C, or 500 °C to about 1000 0 C.
  • membranes of the present invention may selectively separate carbon dioxide from other gases and have a selectivity that is greater than or equal to 5. In other embodiments, a selectivity of carbon dioxide to other gases that is greater than or equal to 10, 25, 50, 100, 150, 200 or 500 maybe possible.
  • carbon dioxide can be shuttled across a membrane as carbonate ions with a counter-current of oxide anions, hi certain embodiments, carbonate ions travel through the membrane in a molten carbonate phase while the counter-current of oxide anions travel in a solid oxide phase, as schematically illustrated in Figure 1.
  • the net flux in the membrane is neutral transport of CO 2 .
  • the present invention affords a structured material in which CO 2 molecules are transferred across the membrane as carbonate ions. For example, regions or layers of molten carbonate 2 alternate with regions or layers of solid oxides 4. hi order to avoid charge build-up in the transport, the negative charge can be transported back through the solid oxide as oxide ions.
  • the net transport is that of a neutral CO 2 .
  • Charged currents flow in this membrane, but they cancel each other out.
  • the CO 2 travels across the membrane by first being converted with an oxide ion into carbonate ions (CO 3 2" ) on the feed side 1 of the membrane for transport in the molten carbonate phase.
  • the oxide ions (O " ) return through the solid oxide phase, by first releasing its CO 2 load.
  • the present invention provides a way to combine the oxide ion mobility of a solid oxide and the carbonate ion mobility in molten carbonates into one structured material so that the net transport is that of neutral CO2.
  • the membrane structure contains a porous solid oxide phase that serves to not only complete the circuit of carbon dioxide transport without an addition external electromotive force (emf), but also provide mechanical support by immobilizing the molten carbonate phase within its porous structure.
  • the membrane is continuous with respect to each phase independently within a three dimensional structure.
  • the driving force for the transport across such a membrane can be due to the partial pressure difference of the CO 2 on the two sides of the membrane. Hence, CO 2 can flow in either direction of the membrane and the actual flow will follow the pressure difference.
  • membranes of the invention have sandwich or fiber-like structures that contain parallel current paths for oxide ions in the solid oxide phase and for carbonate ions in the molten carbonate phase. Such a morphology may provide a high conductance and high selectivity for CO2.
  • a continuous doped zirconia phase allows for the transport of oxide ions from one side of the membrane to the other; and a continous molten carbonate phase provides a pathway for the carbonate ion in the opposite direction (see Figure 1).
  • the present invention provides for a bi-continuous membrane that in one phase conducts oxide ions and a second phase conducts carbonate ions.
  • a bi-continuous membrane as used herein, is a membrane having at least two different and distinct continuous phases from one side of the membrane to the other side of the membrane.
  • a bi-continuous membrane is a membrane where there are passageways for two different charges to migrate through two different materials or phases.
  • the two materials or phases can be arranged in such a way that there are continuous paths connecting the two sides of the membrane in both a solid oxide and a carbonate phase.
  • Additional examples include, but are not limited to, porous media with interconnected liquid- filled pores, solid blocks with straight, tubular channels crossing the solid block matrix like thin pipes, alternating sandwich-like layers, a "Plumber's Nightmare” surface, a gyroid structure, and the like.
  • the invention also relates to a carbon dioxide gas-selective membrane comprising a bi-continuous membrane material stable at a temperature of greater than about 200°C and comprising a porous solid oxide material that in a temperature range of interest is capable of transporting oxide ions, and a molten carbonate phase completely filling the pores capable of conducting carbonate ions, wherein (i) a partial pressure difference of carbon dioxide (from one side of the membrane to the other) drives a flux of carbonate ions across the membrane and (ii) oxide ions return the charge in the solid oxide phase.
  • the invention relates to a carbon dioxide gas-selective membrane comprising at least a bi-continuous structure and having at least two separate ionically conducting phases, hi certain embodiments, CO 2 may be transported across the membrane in one of the phases as a carbonate ion, converted with an oxide ion.
  • the oxide ion may either be dissolved within the molten carbonate or transferred directly from a lattice site at the boundary of a second phase into the carbonate phase.
  • the dissolution of an oxide ion into the carbonate phase may result in a vacant lattice site in the solid oxide phase that is filled by the conductive oxide ions compensating for the carbonate flux as shown in Equation [2]
  • Such a vacant lattice site that is filled by conductive oxide ions eliminates the need for molecular oxygen to contact the membrane along with the carbon dioxide.
  • Kroger- Vink notation is used when reactions involving a crystal lattice are shown. (See Kittel, C, Introduction to Solid State Physics, 4 th ed. 1971, New York: Wiley p. 766).
  • a vacant lattice site normally occupied by the ion is notated as a V.
  • a doubly-positive charged lattice site is notated as, "
  • a doubly-negative charged site (not shown) is notated as "
  • a neutral site is notated as, x .
  • Occupied lattice positions are considered neutral due to the equal charge balance of the neighboring counter ions. Moreover, as shown in Equation [2], diffusion of charged ionic species through the lattice occurs maintaining local charge neutrality within each phase independently.
  • the solid oxide phase and the molten carbonate phase may react with each other to form a third phase. This third phase can be deposited at the boundary of the solid oxide and carbonate phase, but other arrangements can occur as well. For example, a bicontiiiuous membrane consisting of zirconia and lithium carbonate at low partial pressures of CO 2 over the system may release CO 2 and transform itself into a new phase of lithium zirconate as shown in Equation [3].
  • Lithium and oxide ions may incorporate themselves into the zirconium (IV) oxide crystal structure and may create lithium zirconate at the boundary of the two layers.
  • the mobility of lithium ions can help in transferring the oxide ion (that just released a CO 2 ) from the carbonate phase into the zirconia face by allowing charge neutrality conditions to be more easily maintained during such transfer.
  • transfer of the oxide ion from the zirconia phase back into the carbonate phase may be facilitated as described above.
  • operation may occur in a regime where the pressure of CO 2 is high enough to prohibit decomposition of the carbonate phase and conversion into a zirconate or analogous phase, while still providing a substantial partial pressure gradient of CO 2 for reasonable flux across the membrane.
  • less miscible carbonates wherein migration of the cations into the solid oxide phase is hindered, can be used.
  • potassium carbonate or sodium carbonate may be utilized, hi such embodiments, surface treatments can be made to facilitate the transfer of the oxide ions between the oxide and the carbonate phases.
  • catalysts such as platinum and nickel oxide, may be suspended on the solid oxide phase. Such surface treatments need not necessarily be limited to only non-miscible carbonates.
  • the present invention provides membranes having a continuous but porous solid oxide structure wherein the pores are filled with a molten carbonate material.
  • the membrane can be comprised of a solid doped zirconia having pores that are filled with a molten carbonate material.
  • the present invention provides membranes having a continuous but porous solid oxide structure wherein the pores are filled with a carbonate material that under operating conditions is molten.
  • the membrane can be comprised of a solid ziroconia having pores that are filled with a solid carbonate material that under operating conditions become molten.
  • the membrane material comprises doped zirconia and molten carbonates that are mechanically stable in the range of from about 200°C to about 1000 °C, or in the range of from about 300 0 C to about 1000 0 C, or from about 500 0 C to about 1000 0 C 3 and which are devoid of open cracks or pores that allow for indiscriminate gas flow.
  • the membrane is also stable at room temperature.
  • the membrane will not conduct carbonate until the carbonate is molten.
  • the membrane may not begin to separate carbon dioxide until the solid oxide becomes conductive at elevated temperatures such as around 400 °C or higher.
  • the present invention also relates to nano-structured solid oxide membranes with carbonate filled pore spaces that are highly permeable to CO 2 , yet prevent passage of most other materials.
  • the invention provides methods for making materials that achieve a continous doped zirconia phase that allows for the transport of oxide ions from one side of the membrane to the other.
  • the continuous doped zirconia phase may further have pores filled with carbonate material, such as lithium carbonate, forming a continous carbonate phase that allows for the transport of carbonate ion from one side of the membrane to the other.
  • the invention provides for custom materials made from doped zirconia and molten carbonates that are mechanically stable in the range of 400 to 1000°C (without open cracks or pores) and that prohibits indiscriminate gas flow.
  • the invention provides for membrane materials that have a substantial CO2 permeability. As a yardstick to gauge permeability, current flow rates of solid oxide fuels cells and molten carbonate fuel cells can be used to compare with the membranes of the invention.
  • the invention embraces two or more of the foregoing embodiments in combination.
  • the membrane of the present invention may operate over a wide range of temperatures and CO 2 pressures.
  • the present invention provides a structured CO 2 membrane.
  • the membrane can work with any materials where one phase is able to conduct oxide ions, the other phase is able to conduct carbonate ions, and where the two phases can be brought into sufficient contact with each other or through one or more interevening phases so that the charge built up on the phase that is capable of conducting carbonate ions can drive the current flow in the phase that is capable of conducting oxide ions.
  • Some exemplary suitable materials for use in fabricating the membrane include, but are not limited to, a selective CO 2 permeable composition, which is stable and long- lasting under the conditions of preparation and operation at high temperatures.
  • the materials comprising the structured CO 2 membranes of the invention may differ by the cation mixture in the carbonate phase and by admixtures to the solid oxide phase and the carbonate phase to enhance stability, ion permeability and selectivity of the membrane.
  • the materials comprising the membrane can be fabricated into a structured membrane in accordance with this invention, and the net neutral carbon dioxide flux may be established using dynamic pressure measurements and gas chromatography. Use of other gases or an admixture of other gases can establish the selectivity of the membrane for carbon dioxide over a range of temperatures.
  • Materials suitable for the carbonate phase include, but are not limited to, alkali metal carbonates such as sodium, potassium, and lithium carbonates and eutectics or admixtures with each other. Other examples include eutectics of involving calcium, barium, or magnesium carbonates. The choice can depend on the pressure and temperature operating range of the membrane.
  • the carbonate can be molten and retain enough carbonate ions to remain conductive under the prevailing conditions, (i.e.. the carbonate dissociation equilibrium (CO 3 2" ⁇ CO 2 + O 2" ) will not be shifted far to the right).
  • Materials with low melting points and high carbonate ion conductivities such as binary and ternary mixtures of alkali metal carbonates, may be suitable for use as molten carbonate materials.
  • molten carbonate materials such as binary and ternary mixtures of alkali metal carbonates
  • lithium and sodium mixtures having a conductivity of about 2.5 S/cm at 700°C and a eutectic melting point at 50FC may be suitable (see Table 1).
  • Lithium is an effective ion for depressing a mixture melting temperature and for increasing conductivity due to its small size.
  • mixtures that do not form eutectics can also be used.
  • a eutectic mixture is indicated with a star, *.
  • alkali metal carbonates may be susceptible to formation of a third phase, such as a different solid metal oxide, zirconate, or equivalent salt formations, at the carbonate/oxide interface.
  • a third phase such as a different solid metal oxide, zirconate, or equivalent salt formations
  • zirconia (ZrO 2 ) and lithium carbonate (Li 2 CO 3 ) may be reacted together at elevated temperatures (e.g., about 700°C and higher) to form a solid lithium zirconate (Li 2 ZrO 3 ) and CO 2 gas, as shown in Equation [1] above ⁇ see Ida, J.-I.L., And Y.S., Mechanism of High Temperature CO 2 Sorption on Lithium Zirconate. Environmental Science Technology, 2003, 37(9), p. 1999- 2004).
  • alikali metal carbonates may also be doped with low portions of alkali earth carbonates to help maintain the oxobasicity of the solvent, which reduces both decomposition and volatility ⁇ see Cassir, M. and C. Belfine, Technological applications of molten salts: the case of the molten carbonate fuel cells. Plasmas & Ions, 1999(1): p. 3- 15).
  • molten carbonate phase that can wet the solid oxide surface may be utilized to provide sufficient capillary force to hold the molten carbonate salt in the pores of a solid oxide phase.
  • the Young-Laplace equation (Equation [4]) relates capillary force to the pressure differential, ⁇ P, across a cylindrical pore, with pore radii, R, the liquid solid surface tension, ⁇ , and contact angle, ⁇ .
  • ⁇ P 2 * r * C0S ⁇ [4]
  • the maximum pore size at the edges of the membrane for a given pressure drop across the membrane can be calculated using the molten carbonate surface tension and contact angle between the molten carbonate and the oxide interface.
  • the pore structure within the bulk of the material i.e away from the edges) may behave differently than as described above.
  • Immobilizing the molten carbonate salt in the solid oxide porous matrix may further allow coupling of the flux of carbonate ions to oxide vacancies. Immobilization in a porous structure may also serve to depress the possibility of gas-phase species from simply diffusing through the molten phase (see Selman, J.R. and H.C. Mara, Physical Chemistry and Electrochemistry of Alkali Carbonate Melts: With special reference to the molten-carbonate fuel cell, in Advances in Molten Salt Chemistry, G. Mamantov, J. Braunstein, and CB. Mamantov, Editors. 1981, Plenum Press: New York. p. 159-389).
  • Suitable solid oxides can provide pathways for an oxide counter current as well as the structural support of the membrane.
  • Solid oxide that have at least 0.01 S/cm conductivity at operating temperatures ranging from 600-900°C may be suitable.
  • Solid oxides can have resistance to chemical attack by the impregnated molten carbonate mixture and can have the ability to withstand the significant chemical potential gradients of gas mixture compositions maybe suitable. Thermal shock resistance, and thermal expansion coefficients may also be considered to ensure the stability of the porous structure to allow mechanical stabilization of the membrane.
  • the proportion of a material's total conductivity due to an electronic current is called the electronic transference number, t el .
  • the proportion of the conduction due to oxide transport is the ionic transference number, tj on .
  • the range of oxygen chemical potential and temperature over which a material can remain predominately ionically conductive (ti on > 0.99) is called the electrolytic domain (see Kharton, V. V., F.M.B. Marques, and A. Atkinson, Transport properties of solid oxide electrolyte ceramics: a brief review. Solid State Ionics, 2004. 174: p. 135-149).
  • the membrane of the invention may be designed to allow the internal short- circuit of the carbonate ions to come predominantly from the oxide ions.
  • the ability of a solid oxide material to conduct electrons may not necessary decrease or hinder the flux of oxide ions. Without a sink or source of electrons present within the membrane materials or gas phases, an electrical current should not become estabilished.
  • the oxygen-ion conducting phase includes, but are not limited to, zirconium (IV) oxide, cerium (IV) oxide, stabilized bismuth (III) oxide, SFC (Sr-Fe-Co oxides), ABO 3- d e it a (general perovskite crystalline structure, exhibits oxide ionic and electronic conductivity), and the like.
  • the solid oxide phase is made of zirconia or various forms of stabilized zirconia.
  • zirconia may be stabilized with MgO, Y 2 O 3 , CaO, or the like.
  • a more specific example of the perovskite is SrCOo. 8 Fe 0 .2 ⁇ 3- d e ]ta.
  • Solid oxide membranes and sensor membranes can be used.
  • the first class of materials encompassing the first two species in the table, yttria stabilized zirconia (YSZ) and gadolinium stabilized ceria (CGO), are oxides with a cubic fluorite structure.
  • Doped ceria materials may offer higher conductivities at certain temperatures.
  • Gadolinium or samarium doped ceria from 10-20% may provide high ionic conductivities (CGO-10, CGO-20).
  • CGO-10, CGO-20 high ionic conductivities
  • the ionic conductivity is approximately 4 x 10 "2 S/cm. (see Bredesen, R., K. Jordal, and O. Bolland, High-temperature membranes in power generation with CO 2 capture. Chemical Engineering and Processing, 2004. 43(9): p. 1129- 1158).
  • suitable solid oxide materials may be found among oxides having high electron conductivity. For example, despite the high electronic conductivity (due to the easy Bi 3+ - ⁇ Bi 2+ reduction) and low mechanical strength (see Kharton, V. V., F.M.B. Marques, and A. Atkinson, Transport properties of solid oxide electrolyte ceramics: a brief review. Solid State Ionics, 2004. 174: p. 135-149), a fluorite material known for its extremely high conductivity, 5-Bi 2 O 3 , may be a suitable oxide material. 6-Bi 2 O 3 has an ionic conductivity that is greater than 1 S/cm at 750 0 C (see Bredesen, R., K.
  • Bismuth oxide is an example of an intrinsic oxide conductor with every fourth oxide site vacant.
  • Perovskite structures of the LaGaO 3 family are an example. Doping of the lanthanum with strontium and magnesium for gallium can create the oxide vacancies, Lao. 9 Sro. 1 Gao.9Mg 0 . 2 0 3- d (LSGM). (see Ishihara, T., H. Matsuda, and Y. Takita, Effects of rare earth cations doped for La site on the oxide ionic conductivity of LaGaO ⁇ - based perovskite type oxide. Solid State Ionics, 1995. 79: p. 147-151).
  • Porous membrane structures of the conducting solid oxide material may be fabricated with various different techniques.
  • One exemplary, but non-limiting, technique may be tape casting. Tape casting can allow for careful control of porosity, thickness and density and can also tolerate co-sintering of multiple layers (see Mistier, R.E. and E.R. Twiname, Tape Casting: Theory and Practice. 2000: American Ceramic Society). Tape casting initially involves the formation of a workable film (tape) containing ceramic particles suspended inside a polymer matrix. Within this matrix, pore formers, particles of graphite, starch, polycarbonate, or polyethylene that will burn out during the sintering process, can also be included to create an engineered porous structure.
  • Poreformers are organic or carbon particles that are mixed in with ceramic precursors that are later burnt-out during sintering.
  • the final structure is largely independent of the sintering conditions.
  • continuous porosity can be achieved with greater than 20% of the solids loading of the poreformers (see Moulson, AJ. and J.M. Herbert, Electroceramics: Materials, Properties, Applications. 1997, London: Chapman & Hall. 464).
  • the final porous character of the membrane can be analyzed using mercury porosimetry and SEM.
  • Tape casting begins with an organic or aqueous solvent dissolving a dispersant to surround individual ceramic and pore formering particles if a porous structure is desired.
  • dispersant materials include, but are not limited to, polyisobutylene, linoleic acid, oleic acid, lanolin fatty acids, blown menhaden fish oil, and the like.
  • binders are added to suspend the particles in a viscous fluid that can be cast into a thin film.
  • binder materials include, but are not limited to, polyvinyl alcohol, polyvinyl butyral, cellulose, and the like. Further additives, such as plasticizers can be added to control the flexibility and rheology of the suspension.
  • plasticizers include, but are not limited to, poly(ethylene) glycol, poly(propylene) glycol, n-butyl phthalate, dioctyl phthalate, and the like.
  • parameters such as solids loading, binder / dispersant loading, milling time of powder with binder / dispersant, and mill speed can be optimized.
  • the organic solvent evaporates causing the film to shrink and bringing the particles close together. What remains is a polymer matrix suspending ceramic particles and poreformers, called a green body. The green body can be cut or punched to form a desired two dimensional geometry.
  • the tape casting process may allow for a porous solid oxide disk to be co-sintered inside a dense solid oxide frame in order to create a dense surface to form a seal against certain regions of the porous solid oxide disk (see Figure 3).
  • pore forming agents to create a porous structure, or excluding them, resulting in a dense structure.
  • dispersant, binder, plasticizers and solvent can be cast.
  • solvent dryout a void space can be cut out of the tape, to be next filled with a slip containing the same mixture, only now containing poreformers.
  • the additives such as the dispersant, binder, plasticizers and poreformers, can be burnt out, leaving a porous solid oxide structure surrounded by a dense solid oxide structure.
  • both the molten salt and the membrane can be heated to the same temperature, and then the membrane can be dipped into the molten carbonate mixture.
  • the porous solid oxide may be heated to be as hot as the molten carbonate to avoid cooling and solidifying of the salt once it contacts the membrane surface.
  • Molten carbonate uptake may occur via capillary forces drawing the liquid into the solid oxide pore space.
  • the infiltrated membrane can be analyzed with SEM with EDS on both faces to examine if the carbonate infiltrated the entire thickness. XRD can also be used to detect the phases present on the surface.
  • the present invention provides a method for carbon dioxide separation, comprising subjecting a source containing carbon dioxide to the carbon dioxide membrane of the invention described herein.
  • the present invention provides a method for carbon dioxide separation at temperatures greater than about 200 °C.
  • the source may be a fuel gas or an exhaust gas.
  • the invention relates to membranes, methods, and systems for separating of carbon dioxide from fuel gas mixtures and processed fuel gas mixtures.
  • membranes of the present invention may operate from about 300 to about 1200 °C.
  • membranes of the invention may also separate CO 2 from a fuel gas mixture containing hydrogen, water, carbon monoxide, and methane. Membranes of this invention may further separate carbon dioxide from fuel gas streams even if the fuel gas streams contains contaminants such as H 2 S and NH 3 .
  • a zero-emission coal-based electric power plant comprising the carbon dioxide membrane of the invention.
  • the invention provides for a zero-emission coal-based electric power plant comprising the membrane described herein.
  • a fuel cell comprising the carbon dioxide membrane according to the invention is embraced.
  • the carbon dioxide separation membrane may be operating from about 600 °C to about 900 °C in a fuel cell of the present invention.
  • the invention provides a solid oxide fuel cell comprising the membrane described herein.
  • such a membrane can be useful in operating a solid-oxide fuel cell (SOFC) system that can operate on a pure carbon fuel source.
  • SOFC solid-oxide fuel cell
  • the fuel to be oxidized at the anode compartment of the cell stack can be carbon monoxide, generated by a gasification reaction of carbon with CO 2 (Boudouard reaction shown in Equation [5])
  • a better strategy may be to remove excess product CO 2 from a reactor by letting it escape from the reaction vessel through a high temperature selective membrane that is impermeable to CO. Carbon monoxide would not be depleted in the chamber, because additional CO would be generated in the fuel chamber by gasifying a stream of injected carbon. Such a fuel cell could be maintained near the equilibrium point of the Boudouard reaction with the CO 2 selective membrane removing the net production of CO 2 and maintaining the fuel chamber at relatively steady state conditions. In contrast, conventional fuel cell designs tend to drive the fuel content to depletion. Operating near steady state entirely avoids the usually obligatory post- combustion of remnant fuel in the exhaust of the fuel cell stack.
  • the gasification reaction can be performed in a nearly reversible fashion and thus would not consume any of the free energy originally available in the carbon fuel. Furthermore this design would naturally collect CO 2 and ready it for subsequent disposal.
  • An SOFC fuel cell operating in this manner has the highest possible theoretical efficiency of any fuel cell, suggesting that it may be possible to exceed the 70% theoretical efficiency of a high temperature hydrogen fuel cell (see Wade, J. and K. Lackner. Development of a Coal-Based Solid-Oxide Fuel Cell System in The 30th International Technical Conference on Coal Utilization & Fuel Systems. 2005. Clearwater, FL).
  • the carbon dioxide separation membrane may be operating from about 300 0 C to about 600 0 C when used in promoting water gas shift reactions.
  • the membrane of the invention can be used in energy producing devices (such as a solid oxide fuel cell), fuel synthesis, carbon chemistry methods, steel making processes and systems, aluminum smelter and other metallurgical processes.
  • Power plant designs that rely on the recirculation of only partially combusted or oxidized flue gases may benefit greatly from the availability of membranes that can perform the separation at the process temperature (e.g., in excess of 400°C and as high as 1000°C).
  • the efficiency of recirculating the remaining gas can be greatly increased if the gas can retain its sensible heat and does not have to be subjected to a cooling and heating cycle in order to allow for the removal of CO 2 .
  • Zero emission power plants avoid smoke stacks by limiting the inputs to oxygen and carbonaceous fuels.
  • a signature feature of all these power plant designs is that they recirculate the exhaust gases in order to gasify the input fuel or in some cases to dilute the input stream.
  • the present invention may also allow a simple recovery of CO 2 in fuel gas streams.
  • Most hydrocarbon gasification scheme to produce a hydrogen rich fuel makes use of the water gas shift reaction as shown in Equation [6].
  • the system may be limited to low-pressure operation due to the five moles present on the hydrogen side of the reaction versus three on the left side of the reaction.
  • Gasification of a more carbon rich fuel, such as biomass, oil, coal, or charcoal, with oxygen or steam may contain a larger concentration of CO 2 product gas that would favor the use of a high temperature and pressure membrane separation.
  • the membranes of the present invention may be functioning as described below.
  • Oxide conductivity in ceramic materials arises from oxide vacancies or defects within the crystal lattice. Defects can be created by doping a compound with aliovalent counter ions which provide the charge mismatch for vacancies to form. This is common in Group IVB oxides, such as ZrO 2 and CeO 2 , which are doped with alkali earth or rare earth metal cations such as Ca 2+ or Y 3+ . It is also possible for an inorganic compound to have intrinsic oxide vacancies, which is true of 5-Bi 2 O 3 or brownmillerite structures ⁇ see Yamamoto, O., Solid Oxide Fuel Cells: Fundamental aspects and prospects. Electrochimica Acta, 2000. 45: p. 2423-2435).
  • Anion vacancies hold a net positive charge because the site may otherwise be filled with an anion maintaining the charge balance.
  • the electrostatic interaction between the vacancies and other neighboring counter ions impedes the mobility of an ion being able to fill the vacancy.
  • There may be an association enthalpy that must be overcome in order for the defects to become mobile in the solid see Etsell, T.H. and S.N. Flengas, The Electrical Properties of Solid Oxide Electrolytes. Chemical Reviews, 1969. 70(3): p. 340-378).
  • certain solid oxide conductors operate well at elevated temperatures (600-1000°C) and provide functional conductivities ( ⁇ i on > 0.01 S/cm) (see Steele, B.C., Ceramic ion conducting membranes.
  • Alkali metal carbonate salts generally have high conductivities in comparison to that of solid oxide materials at similar temperatures. This is because alkali metal carbonates, and especially eutectic mixtures thereof, have low melting points inducing liquid mobility of the carbonate ions. The electronic conductivities of most alkali metal carbonate mixtures are within the range of 1-2 S/cm (see Selman, J.R. and H.C.
  • Gas phase CO 2 may initially undergo diffusion to the membrane surface.
  • CO 2 may either adsorb onto the solid oxide surface (CO 2(acl )) or dissolve into the molten carbonate phase (CO 2( ⁇ ) (see Equation [8]).
  • the carbonate ions may release CO 2 and leave the oxide ion and CO 2 dissolved in the molten melt.
  • a separate charge transfer reaction balancing the molten carbonate oxide activity and vacancy activity may occur at the interface of the two phases (see Equation [16]).
  • the CO 2 can desorb either into the molten carbonate (see Equation [17]) and then into the gas phase, or can escape directly into the gas phase and diffuse away from the membrane surface (see Equation [18]).
  • the reactions occurring on the membrane surface may not be limited to the reactions listed above. Considerations may have to be made for competing reactions of other gases in the feed mixture and the decomposition reaction of molten carbonates (see Equation
  • the flux or permeance may be correlated to the driving force (which is the partial pressure difference of CO 2 across the membrane) to further elucidate the factors controlling the transport OfCO 2 across a membrane.
  • a first order approximation of expected flux based on the bulk diffusion of ions through the molten carbonate and solid oxide phase can be derived. Because transport within the membrane bulk occurs through ionic motion, a current within each phase is created. Further, the net current must equal zero in the absence of external circuitry as shown in Equation [20] below.
  • the c and v notation are used indicate carbonate ions and vacancy species in each of their respective phases.
  • the tilda, ⁇ , above the chemical potential of these species indicates the extra contribution due to an electrical gradient ( V ⁇ ).
  • the extra term is zero for CO 2 and O o x because their charge numbers, z, are considered 0.
  • Faraday's constant, F, is 96,500 C / mole charge.
  • the chemical potential OfCO 2 can be related back to the activity a COi of CO 2 as follows:
  • Mco 2 M 0 CO2 + RT ⁇ na C0% [24] where R is the gas constant 8.314 J / K mol and T is the temperature in Kelvin.
  • Oxide ions in a crystal lattice become mobile by hopping into vacant crystal lattice sites that would otherwise be occupied by oxide ions. Once an oxide ion hops into an adjacent site, a new vacant space is created where the oxide previously resided. Thus, the charge carrier can be modeled as motion of the dilute vacant sites, rather than that of the numerous oxygen anions present in the solid oxide.
  • the positively charged vacancy neutralizes the charge deficient cation defects.
  • the flux of the mobile charge carriers in a solid oxide material can be given as follows (see Heyne, L., Electrochemistry of Mixed Ionic-Electronic Conductors, in Solid Electrolytes. 1977, Springer- Verlag: Berlin, p. 189-197):
  • the flux as described above is an average over the volume occupied by the solid oxide phase. Because the system in question is porous, the volume fraction occupied by the solid oxide and carbonate conductors must be considered.
  • the porosity of the solid oxide material, ⁇ will be considered as the fractional volume occupied by the flooded molten carbonate phase. This leaves the fractional volume occupied by the oxide conductor as (1- ⁇ ).
  • porosity must be taken into account as follows ⁇ see Newman, J. and K.E. Thomas- Alyea, Electrochemical Methods. 2004, John Wiley & Sons: Hoboken, New Jersey, p. 823):
  • the tilda, ⁇ indicates the flux averaged over the volume occupied by each of the individual phases. Furthermore, the diffusivity is going to be affected by a porous structure, and a corrected diffusivity constant will be marked with a star, *.
  • the flux equation for the doubly charged vaccancy in the solid oxide phase are given as follows:
  • both the alkali metal cations and carbonate ions are mobile species. Furthermore, because this is a molten salt system, an infinitely dilute solution equation cannot be used as a starting point. Rather, to model the transport, it may be best to begin with a force balance (see Newman, J. and K.E. Thomas- Alyea, Electrochemical Methods. 2004, John Wiley & Sons: Hoboken, New Jersey, p. 823):
  • vj is the velocity of species i, cm/s
  • Di j is the diffusivity of species i relative to species j.
  • the term on the right can be considered the driving force per unit volume of species i, proportional to the electrochemical gradient of that species.
  • the driving force is balanced by frictional interactions with other species, j, in the system.
  • the diffusion constant, D y describes the interaction between the two species, and the frictional interaction is proportional to the difference in velocity of the different species.
  • V ⁇ c ⁇ c + 2FV ⁇ 11 [39] because the carbonate has a 2 " charge.
  • Equation [48] shows that bulk diffusion limited flux of CO 2 is dependent upon the pressure difference across the membrane thickness and an average of the conductivities. If the conductivity of one phase far exceeds the other, then flux will be limited by the weaker conductor. This dependence of flux on membrane conductivities will set a maximum thickness on the membrane in order to deliver economically useful permeance. It allows for an upfront calculation on the feasibility of a proposed membrane system.
  • Another impedance to CO 2 transport not captured in the transport analysis may be the polarization of surface reactions.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
  • Inorganic Chemistry (AREA)
  • Manufacturing & Machinery (AREA)
  • General Chemical & Material Sciences (AREA)
  • Dispersion Chemistry (AREA)
  • Sustainable Energy (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Sustainable Development (AREA)
  • Electrochemistry (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Water Supply & Treatment (AREA)
  • Analytical Chemistry (AREA)
  • Separation Using Semi-Permeable Membranes (AREA)
  • Carbon And Carbon Compounds (AREA)

Abstract

L'invention porte sur des membranes à structure bicontinue dans lesquelles une phase conduit un premier type d'ions et une seconde phase conduit un second type d'ions. Selon certains modes de mise en oeuvre, une phase de fusion forme une partie de la phase de la membrane à structure bicontinue et une phase solide forme une autre partie de la phase de la membrane à structure bicontinue. Les matériaux constituant la membrane sont efficaces dans des technologies de séparation et d'absorption et sont fabriqués dans une membrane structurée, selon cette invention. Par exemple, pour séparer le dioxyde de carbone, des carbonates de métaux alcalins, tels que le carbonate de lithium, et des oxydes solides, tels que le zirconium, sont des matériaux appropriés à la préparation de ces types de membranes et peuvent former des couches sélectives et perméables de CO2.
PCT/US2006/014496 2005-04-18 2006-04-18 Membrane conductrice d'ions pour la separation de molecules WO2006113674A2 (fr)

Priority Applications (3)

Application Number Priority Date Filing Date Title
EP06750517A EP1879685A2 (fr) 2005-04-18 2006-04-18 Membrane conductrice d'ions pour la separation de molecules
US13/052,392 US8163065B2 (en) 2005-04-18 2011-03-21 Carbon dioxide permeable membrane
US13/453,300 US8435327B2 (en) 2005-04-18 2012-04-23 Carbon dioxide permeable membrane

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US67239905P 2005-04-18 2005-04-18
US60/672,399 2005-04-18

Related Child Applications (2)

Application Number Title Priority Date Filing Date
US11874707 A-371-Of-International 2006-04-18
US13/052,392 Continuation US8163065B2 (en) 2005-04-18 2011-03-21 Carbon dioxide permeable membrane

Publications (2)

Publication Number Publication Date
WO2006113674A2 true WO2006113674A2 (fr) 2006-10-26
WO2006113674A3 WO2006113674A3 (fr) 2009-03-26

Family

ID=37115843

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US2006/014496 WO2006113674A2 (fr) 2005-04-18 2006-04-18 Membrane conductrice d'ions pour la separation de molecules

Country Status (2)

Country Link
EP (1) EP1879685A2 (fr)
WO (1) WO2006113674A2 (fr)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1966307A2 (fr) * 2005-12-28 2008-09-10 Coorstek Inc. Recuperation de vapeur d'eau au moyen d'une membrane conductrice d'ions mixtes permeable a la vapeur d'eau
WO2008151599A1 (fr) * 2007-06-11 2008-12-18 Forschungszentrum Jülich GmbH Dispositif et procédé destinés à réduire les émissions de co2 issues des gaz d'échappement d'installation de chauffage
WO2013128144A1 (fr) * 2012-03-02 2013-09-06 Ecole Nationale Supérieure Des Mines D'albi-Carmaux Procédé et dispositif de séparation du dioxyde de carbone d'un mélange gazeux
EP2761691A1 (fr) * 2011-09-28 2014-08-06 Phillips 66 Company Électrolyte de pile à combustible à oxyde solide composite
US8945368B2 (en) 2012-01-23 2015-02-03 Battelle Memorial Institute Separation and/or sequestration apparatus and methods
US9780424B2 (en) 2012-09-21 2017-10-03 Danmarks Tekniske Universitet Rechargeable carbon-oxygen battery
WO2018237336A1 (fr) * 2017-06-23 2018-12-27 Lawrence Livermore National Security, Llc Structure céramique poreuse et solution sorbante pour la capture du dioxyde de carbone
US10464015B2 (en) 2016-05-19 2019-11-05 Lawrence Livermore National Security, Llc Molten hydroxide membrane for separation of acid gases from emissions
US10811717B2 (en) 2013-02-13 2020-10-20 Georgia Tech Research Corporation Electrolyte formation for a solid oxide fuel cell device

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3847672A (en) * 1971-08-18 1974-11-12 United Aircraft Corp Fuel cell with gas separator
US4297419A (en) * 1980-09-24 1981-10-27 United Technologies Corporation Anode-matrix composite for molten carbonate fuel cell
US4478776A (en) * 1981-09-30 1984-10-23 Maricle Donald L Method of making molten carbonate fuel cell ceramic matrix tape
US4659635A (en) * 1986-05-27 1987-04-21 The United States Of America As Represented By The United States Department Of Energy Electrolyte matrix in a molten carbonate fuel cell stack
US6514314B2 (en) * 2000-12-04 2003-02-04 Praxair Technology, Inc. Ceramic membrane structure and oxygen separation method
US6793711B1 (en) * 1999-12-07 2004-09-21 Eltron Research, Inc. Mixed conducting membrane for carbon dioxide separation and partial oxidation reactions

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3847672A (en) * 1971-08-18 1974-11-12 United Aircraft Corp Fuel cell with gas separator
US4297419A (en) * 1980-09-24 1981-10-27 United Technologies Corporation Anode-matrix composite for molten carbonate fuel cell
US4478776A (en) * 1981-09-30 1984-10-23 Maricle Donald L Method of making molten carbonate fuel cell ceramic matrix tape
US4659635A (en) * 1986-05-27 1987-04-21 The United States Of America As Represented By The United States Department Of Energy Electrolyte matrix in a molten carbonate fuel cell stack
US6793711B1 (en) * 1999-12-07 2004-09-21 Eltron Research, Inc. Mixed conducting membrane for carbon dioxide separation and partial oxidation reactions
US6514314B2 (en) * 2000-12-04 2003-02-04 Praxair Technology, Inc. Ceramic membrane structure and oxygen separation method

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1966307A4 (fr) * 2005-12-28 2011-06-22 Coorstek Inc Recuperation de vapeur d'eau au moyen d'une membrane conductrice d'ions mixtes permeable a la vapeur d'eau
EP1966307A2 (fr) * 2005-12-28 2008-09-10 Coorstek Inc. Recuperation de vapeur d'eau au moyen d'une membrane conductrice d'ions mixtes permeable a la vapeur d'eau
WO2008151599A1 (fr) * 2007-06-11 2008-12-18 Forschungszentrum Jülich GmbH Dispositif et procédé destinés à réduire les émissions de co2 issues des gaz d'échappement d'installation de chauffage
EP2761691A4 (fr) * 2011-09-28 2015-04-22 Phillips 66 Co Électrolyte de pile à combustible à oxyde solide composite
EP2761691A1 (fr) * 2011-09-28 2014-08-06 Phillips 66 Company Électrolyte de pile à combustible à oxyde solide composite
US8945368B2 (en) 2012-01-23 2015-02-03 Battelle Memorial Institute Separation and/or sequestration apparatus and methods
WO2013128144A1 (fr) * 2012-03-02 2013-09-06 Ecole Nationale Supérieure Des Mines D'albi-Carmaux Procédé et dispositif de séparation du dioxyde de carbone d'un mélange gazeux
FR2987562A1 (fr) * 2012-03-02 2013-09-06 Ensmse Procede et dispositif de separation du dioxyde de carbone d'un melange gazeux
US9780424B2 (en) 2012-09-21 2017-10-03 Danmarks Tekniske Universitet Rechargeable carbon-oxygen battery
US10811717B2 (en) 2013-02-13 2020-10-20 Georgia Tech Research Corporation Electrolyte formation for a solid oxide fuel cell device
US10464015B2 (en) 2016-05-19 2019-11-05 Lawrence Livermore National Security, Llc Molten hydroxide membrane for separation of acid gases from emissions
WO2018237336A1 (fr) * 2017-06-23 2018-12-27 Lawrence Livermore National Security, Llc Structure céramique poreuse et solution sorbante pour la capture du dioxyde de carbone
US11638907B2 (en) 2017-06-23 2023-05-02 Lawrence Livermore National Security, Llc Porous ceramics for additive manufacturing, filtration, and membrane applications

Also Published As

Publication number Publication date
WO2006113674A3 (fr) 2009-03-26
EP1879685A2 (fr) 2008-01-23

Similar Documents

Publication Publication Date Title
US8435327B2 (en) Carbon dioxide permeable membrane
Wade et al. Composite electrolyte membranes for high temperature CO2 separation
Tao et al. A review of advanced proton-conducting materials for hydrogen separation
Hashim et al. Perovskite-based proton conducting membranes for hydrogen separation: A review
EP1879685A2 (fr) Membrane conductrice d'ions pour la separation de molecules
Liu et al. Mixed conducting ceramics for catalytic membrane processing
Leo et al. Development of mixed conducting membranes for clean coal energy delivery
Luo et al. CO2-tolerant oxygen-permeable Fe2O3-Ce0. 9Gd0. 1O2-δ dual phase membranes
Mutch et al. Supported molten-salt membranes for carbon dioxide permeation
Rui et al. Ionic conducting ceramic and carbonate dual phase membranes for carbon dioxide separation
Luo et al. Influence of the preparation methods on the microstructure and oxygen permeability of a CO2‐stable dual phase membrane
Kharton et al. Surface modification of La0. 3Sr0. 7CoO3− δ ceramic membranes
US6468499B1 (en) Method of generating hydrogen by catalytic decomposition of water
Wei et al. Hydrogen permeability and stability of BaCe0. 85Tb0. 05Zr0. 1O3− δ asymmetric membranes
Chen et al. A CO2‐stable hollow‐fiber membrane with high hydrogen permeation flux
CA2608503A1 (fr) Cellule electrochimique directe au charbon haute temperature
CA2582865A1 (fr) Ceramiques conductrices destinees a des systemes electrochimiques
Cheng et al. High-performance microchanneled asymmetric Gd0. 1Ce0. 9O1. 95− δ–La0. 6Sr0. 4FeO3− δ-based membranes for oxygen separation
Chen et al. Hydrogen permeability through Nd5. 5W0. 35Mo0. 5Nb0. 15O11. 25-δ mixed protonic-electronic conducting membrane
Tan et al. Rational design of mixed ionic–electronic conducting membranes for oxygen transport
Salehi et al. Oxygen permeation and stability study of (La0. 6Ca0. 4) 0.98 (Co0. 8Fe0. 2) O3-δ membranes
Meulenberg et al. Proton-conducting ceramic membranes for solid oxide fuel cells and hydrogen (H2) processing
Fontaine et al. CO2 removal at high temperature from multi-component gas stream using porous ceramic membranes infiltrated with molten carbonates
Carvalho et al. Tape-casting and freeze-drying gadolinia-doped ceria composite membranes for carbon dioxide permeation
Thursfield et al. High temperature gas separation through dual ion-conducting membranes

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application
NENP Non-entry into the national phase

Ref country code: DE

WWE Wipo information: entry into national phase

Ref document number: 2006750517

Country of ref document: EP

NENP Non-entry into the national phase

Ref country code: RU