Classifications

• • 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
  • B01D69/12—Composite membranes; Ultra-thin membranes
• • 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
  • B01D61/007—Separation by stereostructure, steric separation
• • 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
  • B01D69/02—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor characterised by their properties
• • 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
  • B01D71/00—Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
  • B01D71/06—Organic material
  • B01D71/44—Polymers obtained by reactions only involving carbon-to-carbon unsaturated bonds, not provided for in a single one of groups B01D71/26-B01D71/42
• • 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
  • B01D71/80—Block polymers

Definitions

• This invention pertains to mixed matrix membranes having greatly improved performance in separation of gases. More particularly, the invention pertains to improved mixed matrix membranes containing high surface area microporous polymers.
• Membrane gas separation is of special interest to petroleum producers and refiners, chemical companies, and industrial gas suppliers.
• Several applications have achieved commercial success, including CO 2 removal from natural gas and from biogas and enhanced oil recovery.
• UOP' s Separex® membrane is currently an international market leader for CO 2 removal from natural gas.
• the membranes most commonly used in commercial gas separation applications are polymeric and nonporous. Separation is based on a solution-diffusion mechanism. This mechanism involves molecular-scale interactions of the permeating gas with the membrane polymer.
• the membrane performance in separating a given pair of gases is determined by two parameters: the permeability coefficient (P A ) and the selectivity (OC A / B )-
• P A is the product of the gas flux and the membrane thickness, divided by the pressure difference across the membrane.
• Gases can have high permeability coefficients because of a high solubility coefficient, a high diffusion coefficient, or both coefficients, hi general, the diffusion coefficient decreases while the solubility coefficient increases with an increase in the molecular size of the gas.
• both high permeability and selectivity are desirable because higher permeability decreases the size of the membrane area required to treat a given volume of gas, thereby decreasing capital cost of membrane units, and because higher selectivity results in a higher purity product gas.
• Polymers provide a range of properties including low cost, high permeability, good mechanical stability, and ease of processability that are important for gas separation.
• a polymer material with a high glass-transition temperature (Tg), high melting point, and high crystallinity is preferred.
• Glassy polymers i.e., polymers at temperatures below their Tg
• polymers which are more permeable are generally less selective than are less permeable polymers.
• a general trade-off has always existed between permeability and selectivity (the so-called polymer upper bound limit).
• CA Cellulose acetate
• the present invention describes a novel polymer/polymer mixed matrix membrane and the use of such membranes in gas separation applications. More specifically, the invention involves the preparation of polymer/polymer MMMs incorporating soluble polymers of intrinsic microporosity as microporous fillers.
• polymer/polymer MMMs incorporating soluble polymers of intrinsic microporosity as fillers.
• new types of polymer/polymer MMMs containing polymers of intrinsic microporosity as fillers have been prepared.
• soluble polymeric fillers possessing intrinsic microporosity are incorporated into a continuous polymer matrix.
• the polymeric fillers exhibit a rigid rod-like, randomly contorted structure which allows them to exhibit intrinsic microporosity.
• polymeric fillers of intrinsic microporosity exhibit behavior analogous to that of conventional microporous materials including large and accessible surface areas, interconnected micropores of less than 2 nm in size, as well as high chemical and thermal stability, but, in addition, possess properties of conventional polymers including good solubility and easy processability.
• those polymeric fillers that possess polyether polymer chains have favorable interaction between carbon dioxide and the ethers within the chain. These polymeric fillers were found to reduce the hydrocarbon fouling problem of polyimide membranes.
• the solubility of the microporous polymeric fillers offers significant advantages over conventional insoluble microporous materials in the preparation of MMMs.
• the polymer matrix can be selected from all kinds of glassy polymers such as polyimides (e.g., Matrimid®), polyetherimides (e.g., Ultem®), cellulose acetates, polysulfones, and polyethersulfones.
• polyimides e.g., Matrimid®
• polyetherimides e.g., Ultem®
• cellulose acetates cellulose acetates
• polysulfones e.g., Ultem®
• cellulose acetates e.g., polysulfones, and polyethersulfones.
• These polymer/polymer MMMs combine the properties of both the continuous polymer matrix and the dispersed polymeric fillers. Gas separation experiments on these MMMs show dramatically enhanced gas separation performance for CO 2 removal from natural gas.
• Mixed matrix membranes prepared in accordance with the present invention can also be used in the separation of the following pairs of gases: hydrogen/methane, carbon dioxide/nitrogen, me
• MMMs Mixed matrix membranes
• microporous solid materials may retain polymer processability and improve selectivity for gas separation due to the superior molecular sieving and sorption properties of the microporous materials.
• MMMs have received world-wide attention during the last two decades. For most cases, however, high solid loading is required to obtain substantial enhancement of gas separation properties. High solid loading, however, results in poor mechanical and processing properties mainly because of the aggregation of the solid particles in the polymer matrix and the poor adhesion between the inorganic solid particles and the organic polymer matrix.
• the membranes of the present invention are especially useful in the purification, separation or adsorption of a particular species in the liquid or gas phase.
• these membranes may, for example, be used for the separation of proteins or other thermally unstable compounds, e. g. in the pharmaceutical and biotechnology industries.
• the membranes may also be used in fermenters and bioreactors to transport gases into the reaction vessel and transfer cell culture medium out of the vessel. Additionally, the membranes may be used for the removal of microorganisms from air or water streams, water purification, ethanol production in a continuous fermentation/membrane pervaporation system, and in detection or removal of trace compounds or metal salts in air or water streams.
• the membranes are especially useful in gas/vapor separation processes in chemical, petrochemical, pharmaceutical and allied industries for removing organic vapors from gas streams, e. g.
• membranes in off-gas treatment for recovery of volatile organic compounds to meet clean air regulations, or within process streams in production plants so that valuable compounds (e. g.,vinylchloride monomer, propylene) may be recovered.
• gas/vapor separation processes in which these membranes may be used are hydrocarbon vapor separation from hydrogen in oil and gas refineries, for hydrocarbon dew pointing of natural gas (i.e. to decrease the hydrocarbon dew point to below the lowest possible export pipeline temperature so that liquid hydrocarbons do not separate in the pipeline), for control of methane number in fuel gas for gas engines and gas turbines, and for gasoline recovery.
• the membranes may incorporate a species that adsorbs strongly to certain gases (e.g. cobalt porphyrins or phthalocyanines for O 2 or silver(I) for ethane) to facilitate their transport across the membrane.
• These membranes may also be used in the separation of liquid mixtures by pervaporation, such as in the removal of organic, compounds (e. g. , alcohols, phenols, chlorinated hydrocarbons, pyridines, ketones) from water such as aqueous effluents or process fluids.
• organic, compounds e. g. , alcohols, phenols, chlorinated hydrocarbons, pyridines, ketones
• a membrane which is ethanol-selective would be used to increase the ethanol concentration in relatively dilute ethanol solutions (5-10% ethanol) obtained by fermentation processes.
• Further liquid phase examples include the separation of one organic component from another organic component, e. g. to separate isomers of organic compounds.
• Mixtures of organic compounds which may be separated using an inventive membrane include: ethylacetate- ethanol, diethylether-ethanol, acetic acid-ethanol, benzene-ethanol, chloroform- ethanol, chloroform-methanol, acetone- isopropylether, allylalcohol-allylether.allylalcohol- cyclohexane, butanol-butylacetate, butanol- 1 -butylether,ethanol-ethylbutylether, propylacetate-propanol, isopropylether-isopropanol, methanol-ethanol-isopropanol, and ethylacetate-ethanol-acetic acid.
• the membranes may be used for gas separation. Examples of such separation include separation of an organic gas from an atmospheric gas, such as nitrogen or oxygen. A further example of such a separation is for the separation of organic gases from each other.
• the membranes may be used for separation of organic molecules from water (e.g. ethanol and/or phenol from water by pervaporation) and removal of metal and other organic compounds from water.
• An additional application for the membranes is in chemical reactors to enhance the yield of equilibrium-limited reactions by selective removal of a specific product in an analogous fashion to the use of hydrophilic membranes to enhance esterification yield by the removal of water.
• the present invention pertains to polymer/polymer mixed matrix membrane (MMM) (or polymer/polymer mixed matrix film) containing soluble polymers of intrinsic microporosity as fillers.
• MMM polymer/polymer mixed matrix membrane
• the solubility of the microporous polymeric fillers offers significant advantages over the use of conventional insoluble microporous materials in the preparation of MMMs.
• These new MMMs have immediate applications for the separation of gas mixtures including carbon dioxide removal from natural gas.
• the mixed matrix membrane permits carbon dioxide to diffuse through at a faster rate than the methane in the natural gas.
• Carbon dioxide has higher permeation rate than methane because of higher solubility, higher diffusivity, or both.
• carbon dioxide enriches on the permeate side of the membrane, and methane enriches on the feed (or reject) side of the membrane.
• any given pair of gases that differ in size for example nitrogen and oxygen, carbon dioxide and methane, hydrogen and methane or carbon monoxide, helium and methane, can be separated using the mixed matrix membranes described herein. More than two gases can be removed from a third gas.
• some of the components which can be selectively removed from a raw natural gas using the membranes described herein include carbon dioxide, oxygen, nitrogen, water vapor, hydrogen sulfide, helium, and other trace gases.
• Some of the components that can be selectively retained include hydrocarbon gases.
• the polymer/polymer mixed matrix membranes developed in this invention are homogeneous organic-organic membranes comprising homogeneously distributed organic microporous polymer fillers throughout a continuous polymer phase.
• the organic microporous polymer fillers incorporated into the polymer matrix possess intrinsic microporosity.
• the organic microporous polymer fillers incorporated into the polymer matrix are soluble in the same solvent as that used for dissolving the polymer matrix, so that aggregation and poor adhesion problems are prevented.
• the resulting polymer/polymer mixed matrix membrane has a steady state permeability differ from that of the pure polymer due to the combination of the molecular sieving gas separation mechanism of the microporous polymer filler phase with the solution-diffusion gas separation mechanism of both the polymer matrix phase and the microporous polymer filler phase.
• Design of the polymer/polymer mixed matrix membranes containing the microporous organic polymer fillers described herein is critically based on the proper selection of both microporous organic polymer filler and the continuous polymer matrix. Materials selection for both microporous organic polymer filler and the continuous polymer matrix is a key aspect for the preparation of these polymer/polymer mixed matrix membranes.
• Polymers provide a wide range of properties important for separations, and modifying them can improve membrane selectivity.
• a material with a high glass transition temperature (Tg), high melting point, and high crystallinity is preferred for most gas separations.
• Glassy polymers i.e., polymers below their Tg
• the membrane fabricated from the pure polymer which can be used as the continuous polymer phase in the mixed matrix membranes, exhibits a carbon dioxide or hydrogen over methane selectivity of at least 15, more preferably at least 30.
• the polymer used as the continuous polymer phase in the polymer/polymer mixed matrix membrane is a rigid, glassy polymer.
• Typical polymers suitable for polymer/polymer mixed matrix membrane preparation as the continuous polymer phase can be selected from polysulfones; poly(styrenes), including styrene-containing copolymers such as acrylonitrilestyrene copolymers, styrene-butadiene copolymers and styrene-vinylbenzylhalide copolymers; polycarbonates; cellulosic polymers, such as cellulose acetate, cellulose triacetate, cellulose acetate-butyrate, cellulose propionate, ethyl cellulose, methyl cellulose, nitrocellulose, etc.; polyimides, polyetherimides, and polyamides, including aryl polyamides, aryl polyimides such as Matrimid ® 5218 and aryl polyetherimides such as Ultem ® 1000; polyethers; poly(arylene oxides) such as poly(phenylene oxide) and poly(xylene oxide); poly(st
• Typical substituents providing substituted polymers include halogens such as fluorine, chlorine and bromine; hydroxyl groups; lower alkyl groups; lower alkoxy groups; monocyclic aryl; lower acyl groups and the like.
• Microporous materials are defined as solids that contain interconnected pores of less than 2 nm in size and consequently, they possess large and accessible surface areas-typically 300- 1500 m 2 g " ' as measured by gas adsorption.
• the discrete porosity provides molecular sieving properties to these materials which have found wide applications as catalysts and sorption media.
• Microporous polymer materials (or as so-called "polymers of intrinsic microporosity") described herein are polymeric materials that possess microporosity that is intrinsic to their molecular structures. See McKeown, et al, CHEM. COMMUN., 2780 (2002); McKeown, et al., CHEM. COMMUN., 2782 (2002); Budd, et al., J. MATER. CHEM., 13:2721 (2003); Budd, et al., CHEM. COMMUN., 230 (2004); Budd, et al., ADV. MATER., 16:456 (2004); McKeown, et al., CHEM. EUR.
• the polymeric fillers have rigid rod-like, randomly contorted structure to generate intrinsic microporosity.
• These polymeric fillers of intrinsic microporosity exhibit analogous behavior to that of conventional microporous materials such as large and accessible surface areas, interconnected intrinsic micropores of less than 2 nm in size, as well as high chemical and thermal stability, but, in addition, possess properties of conventional polymers such as good solubility and easy processability.
• these polymeric fillers possess polyether polymer chains that have favorable interaction between carbon dioxide and the ethers. These polymeric fillers also can reduce the hydrocarbon fouling problem of the polyimide membranes.
• microporous polymeric fillers offer significant advantages over conventional insoluble microporous materials in the preparation of MMMs. These microporous polymer materials are selected as the fillers in the preparation of polymer/polymer mixed matrix membranes. Representative examples of microporous polymer materials described herein as fillers are shown below (PIMs) followed by (network-PIMs).
• the dioxane formation offers a general reaction for the preparation of PIMs from appropriate hydroxylated aromatic monomers (e.g., A1-A7) and fluorinated (or chlorinated) aromatic monomers (e.g., B1-B7) as shown in Figure 1.
• the most preferred microporous polymer materials to be used as fillers with the present invention may be prepared according to the literature procedure. The synthesis of microporous polymer materials is well established in the literature.
• efficient dibenzodioxane-forming reaction i.e.
• the thermal stability of PIMl was determined by thermal analysis, which indicates that PIMl is thermally stable up to 370 0 C.
• the surface area and the pore size distribution of the microporous polymer fillers were characterized by nitrogen adsorption- desorption measurements which demonstrated that PIMl is microporous with high surface area of 785 m g " .
• Micropore analysis using BJH method indicates a significant proportion of micropores had dimensions in the range of less than 1.5 nm. There is also evidence of some mesoporosity.
• the microporosity of the PIMl arises from its high rigidity combined with a randomly contorted shape so that other polymers of high rigidity with a randomly contorted shape are useful in the present invention.
• Polymer/polymer mixed matrix membranes containing microporous polymer fillers were fabricated by mixing certain amount of microporous polymer fillers in a continuous polymer matrix.
• the most preferred polymer/polymer mixed matrix membranes used in this present invention were fabricated as follows. Polymer/polymer mixed matrix dense films were prepared from solution casting of a homogeneous solution of microporous polymer fillers and a continuous polymer matrix.
• the solvents that can be used for dissolving both microporous polymer fillers and the continuous polymer matrix include methylene chloride, THF, acetone, DMF, NMP, DMSO, and others known to those skilled in the art.
• the loading of the microporous polymer fillers in the mixed matrix dense films may vary from 1 to 50 wt-% depending upon the properties sought as well as the dispersibility of the particular microporous polymer filler in the particular continuous polymer.
• Selected amounts of microporous polymer as fillers and polymer as matrix were added to an organic solvent. After stirring for 2 hours, both polymers dissolved completely in the solvent to form a transparent homogeneous solution.
• the polymer solutions with microporous polymer filler loading of 1, 10, 20, 30, 40, and 50 wt-% (based on weight of polymer matrix) were poured into glass rings on top of a clean glass plate, and dried at room temperature inside a plastic cover for at least 12 hours to obtain the final polymer/polymer mixed matrix dense films.
• the dense films were detached from the glass plate and dried at room temperature for 24 hours and then at 110 0 C for at least 48 hours under vacuum. AU the dense films are transparent and were around 1-3 mils thick.
• the permeability (P) and selectivity (CX CO2/CH 4) of the polymer/polymer mixed matrix membranes with microporous polymer fillers (or mixed matrix dense films) were measured by pure gas measurements at 50 0 C under 690 kPa (100 psig) pressure.
• the polymer/polymer mixed matrix dense films containing microporous polymer fillers offer dramatically enhanced P (orders of improvement) compared to that of pure polymer matrix.
• the mechanical strength of the polymer/polymer mixed matrix dense films with 30 wt-% microporous polymer filler loading is nearly the same as that of the pure polymer matrix. No phase separation is observed with up to 30 wt-% incorporation of the microporous polymer fillers into the continuous polymer matrix.

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• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Engineering & Computer Science (AREA)
• Dispersion Chemistry (AREA)
• Analytical Chemistry (AREA)
• General Chemical & Material Sciences (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Water Supply & Treatment (AREA)
• Separation Using Semi-Permeable Membranes (AREA)
• Compositions Of Macromolecular Compounds (AREA)
• Polyethers (AREA)
• Macromolecular Compounds Obtained By Forming Nitrogen-Containing Linkages In General (AREA)

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• 2008
  • 2008-07-02 EP EP08772343.3A patent/EP2293863A4/de not_active Withdrawn
  • 2008-07-02 KR KR1020117002062A patent/KR101558027B1/ko not_active Expired - Fee Related
  • 2008-07-02 JP JP2011516259A patent/JP5179659B2/ja not_active Expired - Fee Related
  • 2008-07-02 CN CN2008801306426A patent/CN102112203A/zh active Pending
  • 2008-07-02 BR BRPI0822900-7A patent/BRPI0822900A2/pt not_active IP Right Cessation
  • 2008-07-02 AU AU2008358898A patent/AU2008358898B2/en not_active Ceased
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