WO2013036693A2 - Process for fabricating pbi hollow fiber asymmetric membranes for gas separation and liquid separation - Google Patents

Process for fabricating pbi hollow fiber asymmetric membranes for gas separation and liquid separation Download PDF

Info

Publication number
WO2013036693A2
WO2013036693A2 PCT/US2012/054033 US2012054033W WO2013036693A2 WO 2013036693 A2 WO2013036693 A2 WO 2013036693A2 US 2012054033 W US2012054033 W US 2012054033W WO 2013036693 A2 WO2013036693 A2 WO 2013036693A2
Authority
WO
WIPO (PCT)
Prior art keywords
layer
hollow fiber
polybenzimidazole
range
asymmetric hollow
Prior art date
Application number
PCT/US2012/054033
Other languages
French (fr)
Other versions
WO2013036693A3 (en
Inventor
Indira Jayaweera
Gopala N. Krishnan
Angel Sanjurjo
Palitha Jayaweera
Srinivas BHAMIDI
Original Assignee
Sri International
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 Sri International filed Critical Sri International
Priority to JP2014528706A priority Critical patent/JP6062945B2/en
Priority to KR1020147005734A priority patent/KR101951065B1/en
Priority to CN201280043088.4A priority patent/CN103781536B/en
Publication of WO2013036693A2 publication Critical patent/WO2013036693A2/en
Publication of WO2013036693A3 publication Critical patent/WO2013036693A3/en
Priority to US14/190,100 priority patent/US9321015B2/en

Links

Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D69/00Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
    • B01D69/12Composite membranes; Ultra-thin membranes
    • B01D69/1216Three or more layers
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D69/00Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
    • B01D69/08Hollow fibre membranes
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D53/00Separation 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
    • B01D53/22Separation 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
    • B01D53/228Separation 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
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D69/00Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
    • B01D69/02Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor characterised by their properties
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D69/00Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
    • B01D69/08Hollow fibre membranes
    • B01D69/085Details relating to the spinneret
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D69/00Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
    • B01D69/08Hollow fibre membranes
    • B01D69/087Details relating to the spinning process
    • B01D69/088Co-extrusion; Co-spinning
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D69/00Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
    • B01D69/12Composite membranes; Ultra-thin membranes
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D69/00Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
    • B01D69/12Composite membranes; Ultra-thin membranes
    • B01D69/1218Layers having the same chemical composition, but different properties, e.g. pore size, molecular weight or porosity
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D71/00Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
    • B01D71/06Organic material
    • B01D71/58Other polymers having nitrogen in the main chain, with or without oxygen or carbon only
    • B01D71/62Polycondensates having nitrogen-containing heterocyclic rings in the main chain
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D71/00Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
    • B01D71/06Organic material
    • B01D71/76Macromolecular material not specifically provided for in a single one of groups B01D71/08 - B01D71/74
    • B01D71/82Macromolecular 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
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D2325/00Details relating to properties of membranes
    • B01D2325/02Details relating to pores or porosity of the membranes
    • B01D2325/022Asymmetric membranes
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D2325/00Details relating to properties of membranes
    • B01D2325/02Details relating to pores or porosity of the membranes
    • B01D2325/022Asymmetric membranes
    • B01D2325/0231Dense layers being placed on the outer side of the cross-section
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D2325/00Details relating to properties of membranes
    • B01D2325/04Characteristic thickness
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D2325/00Details relating to properties of membranes
    • B01D2325/30Chemical resistance

Abstract

The invention provides methods for preparing an asymmetric hollow fiber, the asymmetric hollow fibers prepared by such methods, and uses of the asymmetric hollow fibers. One method involves passing a polymeric solution through an outer annular orifice of a tube-in-orifice spinneret, passing a bore fluid though an inner tube of the spinneret, dropping the polymeric solution and bore fluid through an atmosphere over a dropping distance, and quenching the polymeric solution and bore fluid in a bath to form an asymmetric hollow fiber.

Description

Process for Fabricating PBI Hollow Fiber Asymmetric Membranes for Gas Separation and Liquid Separation
Assignee: SRI International
Inventors: Indira Jayaweera, Gopala N. Krishnan, Angel Sanjurjo, Palitha Jayaweera and Srinivas Bhamidi
[001] Cross-Reference to Related Applications
[002] This application claims priority to US Ser. No. 61/531,448, filed Sep 06, 2011, the disclosure of which is incorporated herein by reference in its entireties.
[003] Statement of Government Interest
[004] This invention was made with United States Government support under N00014-10-C-0059 awarded by the Office of Naval Research, and under DE-FC26- 07NT43090 awarded by the Department of Energy. The United States Government has certain rights in this invention.
[005] Introduction
[006] Many industries from water treatment to gas separations use membrane processes for separation and purification. These processes commonly use polymeric membranes in flat sheet or hollow fiber form. The hollow fiber membranes are more widely used than flat sheet membranes because of their high surface area to volume ratio.
[007] Relevant art includes US 7771518, US 5683584, and US 2011/0266223. [008] Summary of the Invention
[009] In one aspect, the invention provides a method for preparing an asymmetric hollow fiber, the method comprising: (a) passing, through an outer annular orifice of a tube-in-orifice spinneret, a polymeric solution comprising: (i) 15-25 wt% of a polybenzimidazole; (ii) 1-5 wt% of a polymeric pore-forming material; and (iii) a solvent with respect to the polybenzimidazole; (b) passing, though an inner tube of the spinneret, a bore fluid comprising: (i) 65-99 wt. % of a non-solvent with respect to the polybenzimidazole; and (ii) 1-35 wt. % of a solvent with respect to the polybenzimidazole, wherein the bore fluid maintains the polymeric solution in an annular shape; (c) dropping the polymeric solution and bore fluid through a gap, wherein the gap comprises an atmosphere and a dropping distance of 0.3 to 20 cm; (d) quenching the polymeric solution and bore fluid in a bath to form an asymmetric hollow fiber having an annular shape and comprising first and second concentric layers, wherein the first layer contacts the second layer and is non-porous, and wherein the second layer is porous having pores in the range 5-250 nm.
[010] In embodiments:
[011] The method further comprises taking up the fiber into a fiber bundle at a rate of 1-100 meters/min. The fiber bundle can be used as a hollow fiber membrane in suitable membrane applications such as those described herein.
[012] The polymeric solution is stable against chemical degradation for at least 6 months within a temperature range of 15-25 °C.
[013] The method further comprises post-spinning washing and drawing of the fiber. The post-spinning procedures, for example, increase the mechanical strength of the fibers.
[014] The polybenzimidazole is sulfonated polybenzimidazole.
[015] The first layer forms an outer surface and the second layer forms an inner surface of the asymmetric hollow fiber.
[016] The first layer forms an inner surface and the second layer forms an outer surface of the asymmetric hollow fiber
[017] The thickness of the first and second layers is controlled by the length of the dropping distance and by the relative polarities of the solvent and non-solvent.
[018] The first layer has a thickness in the range 0.1-10 μιτι, and wherein the second layer has a thickness in the range of 10-500 μιη.
[019] The chemical composition of the first layer and the chemical composition of the second layer are the same.
[020] The polymer precipitate partially solidifies during the dropping and fully solidifies during the quenching.
[021] The outer annular orifice of the tube-in-orifice spinneret has an outside diameter in the range 100-2000 μιη. [022] The thickness of the first and second layers is controlled by the length of the dropping distance and by the relative polarities of the solvent and non-solvent, and wherein the polybenzimidazole is sulfonated polybenzimidazole.
[023] The first layer has a thickness in the range 0.1-10 μιτι, and wherein the second layer has a thickness in the range of 10-500 μιτι, and wherein the polymer precipitate partially solidifies during the dropping and fully solidifies during the quenching.
[024] In another aspect, there is provided an asymmetric hollow fiber comprising first and second concentric layers forming a wall of the fiber, wherein: the asymmetric hollow fiber comprises a polybenzimidazole material; the first layer is non-porous and the second layer is porous having pores in the range 5-250 nm; and the asymmetric hollow fiber has an outside diameter in the range 100-2000 μιη.
[025] In embodiments:
[026] The polybenzimidazole is sulfonated polybenzimidazole.
[027] The asymmetric hollow fiber is stable against chemical degradation up to 400
°C.
[028] The first layer has a thickness in the range 0.1-10 μιτι, and wherein the second layer has a thickness in the range of 10-500 μιη.
[029] The first layer forms an outer surface and the second layer forms an inner surface of the asymmetric hollow fiber.
[030] In another aspect, there is provided a membrane comprising the asymmetric hollow fiber comprising: a polybenzimidazole; and first and second concentric layers, wherein the first layer is non-porous and the second layer is porous having pores in the range 5-250 nm, wherein the fiber has an outside diameter in the range 100-2000 μιη.
[031] In embodiments:
[032] The membrane is used in a method for separating H2 from a gas mixture comprising H2, C02, CO, and methane, the method comprising passing the gas mixture through the membrane.
[033] The membrane is used in a method for removing impurities from a water solution, the method comprising passing the water solution through the membrane.
[034] The invention specifically provides all combinations of the recited aspects, as if each had been laboriously individually set forth. [035] Detailed Description of Particular Embodiments
[036] In one aspect, the invention provides a method for preparing an asymmetric hollow fiber, the method comprising: (a) passing, through an outer annular orifice of a tube-in-orifice spinneret, a polymeric solution comprising: (i) 15-25 wt% of a polybenzimidazole; (ii) 1-5 wt% of a polymeric pore-forming material; and (iii) a solvent with respect to the polybenzimidazole; (b) passing, though an inner tube of the spinneret, a bore fluid comprising: (i) 65-99 wt. % of a non-solvent with respect to the polybenzimidazole; and (ii) 1-35 wt. % of a solvent with respect to the
polybenzimidazole, wherein the bore fluid maintains the polymeric solution in an annular shape; (c) dropping the polymeric solution and bore fluid through an
atmosphere over a dropping distance of 0.3 to 20 cm; (d) quenching the polymeric solution and bore fluid in a bath to form an asymmetric hollow fiber comprising first and second concentric layers, wherein the first layer is non-porous and the second layer is porous having pores in the range 5-250 nm.
[037] The polymeric solution carries the polymeric material that forms the
asymmetric hollow fibers, and in some embodiments carries one or more additional components such as a pore-forming material, salts, pH-modifying agents, viscosity modifying agents, and one or more solvents.
[038] The polymeric solution comprises a polybenzimidazole (PBI). In some embodiments, the PBI is sulfonated. Sulfonation can be carried out using any convenient method. For example, the sulfonated version of PBI can be readily prepared by treating with sulfuric acid to form covalently bonded SO3- with the proton forming a stable bond with the nitrogen of the imidazole ring. Sulfonated PBI (SPBI) hollow-fibers provide higher chlorine tolerance, water flux, and salt rejection rates. The PBI can be present in an amount effective to create asymmetric hollow fibers according to the inventive methods. In embodiments, the PBI is present in an amount ranging from 10-30, or 15- 25, or 15-20 wt%, or in an amount greater than 10, 15, 17, 20, or 25 wt%, or less than 30, 25, 22, 20, or 18 wt%. More than one type of PBI can be present, provided that the total weight percent is within the given ranges.
[039] In embodiments, the polymeric solution comprises a pore forming material. The pore forming material is a material that causes or aids the formation of pores in the materials of the invention. For example, the pore forming material aids the solvent exchange mechanism of pore formation. Any appropriate pore forming material can be used. Examples of pore forming materials are compounds containing multiple hydroxyl groups, such as glycols and polyols. Examples include isopropanol, ethylene glycol, propylene glycol, polyvinylalcohol, saccharides and polysaccharides, and the like.
Another example of a pore-forming material is PVP. The pore forming material is present in the polymeric solution in an amount sufficient to cause the desired porosity in the resulting asymmetric hollow fibers. In embodiments, the pore forming material is present in the polymeric solution in the range 1-5 wt%, or 1-3 wt%, or less than 5, 4, 3, or 2 wt%, or greater than 1, 2, 3, or 4 wt%.
[040] The polymeric solution comprises a solvent with respect to the PBI. Such a solvent is able to fully dissolve the PBI present in the solution and under the conditions used in the inventive methods. Examples of suitable solvents are N,N- dimethylacetamide (DMAc), dimethylsulfoxide (DMSO), N-N-dimethylformamide (DMF), N-methyl-2-pyrrolidine (NMP), pyridine and the like. Combinations of solvents are also suitable.
[041] The polymeric solution may further comprise one or more additives such as LiCl (e.g., as a stabilizer of PBI).
[042] The polymeric solution is stable against chemical degradation for at least 6 months under ambient conditions, such as within a temperature range of 15-25 °C. In some embodiments, the polymeric solution is stable for at least 9 or 12 months. Thus, the components of the polymeric solution (particularly the PBI component) do not undergo significant degradation over the period of stability. For example, there is less than 10, 8, 5, 3, 2, or 1% degradation of the PBI component in a polymeric solution over the period of stability provided that the solution is maintained in a temperature range of 15-25 °C.
[043] The inventive methods involve passing the polymeric solution through an outer annular orifice of a tube-in-orifice spinneret. The passing can be carried out at elevated pressure (i.e., the polymeric solution can be forced through the orifice), or the solution can be allowed to drop out of the orifice under the influence of gravity and at ambient pressure. Oriented below the outer annular orifice is a gap that may conveniently be segmented into an expansion region immediately below the outer annular orifice and an elongation region below the expansion region. Upon emergence from the outer orifice of the spinneret, the polymeric solution (which has the annular shape of the annular orifice) first enters the expansion region where it expands in circumference slightly. The polymeric solution moves through the expansion region and then enters the elongation region where the circumference is reduced. In some embodiments, a portion of the solvent evaporates from the polymeric solution as the polymeric solution passes through the gap. The evaporation increases the concentration of PBI within the polymeric solution, and some solidification of the PBI may take place within the gap. The polymeric solution moves through the elongation region of the gap and enters a bath positioned below the gap. The bath functions to coagulate the PI within the polymeric solution, such that the PBI solidifies completely within the bath.
Furthermore, solvent exchange occurs within the bath (i.e., solvent from the polymeric solution exchanges with solvent from the bath). The solvent exchange results in the formation of pores within the solidifying PBI.
[044] The inventive methods further involve passing a bore fluid through an inner tube of the tube-in-orifice spinneret. The inner tube is centrally positioned (with respect to the center axis of the spinneret) within the outer annular orifice. The bore fluid is used to maintain the polymeric solution in an annular shape during the dropping of the polymeric solution through the gap and into the bath. Thus, bore fluid emerges from the inner tube at the same time that polymeric solution emerges from the outer annular orifice.
[045] The bore fluid comprises a mixture of a solvent with respect to the PBI and a non-solvent with respect to the PBI. In embodiments, the bore fluid comprises 65-99 wt%, or greater than 65, 70, 75, 80, 85, or 90 wt%, or less than 99, 95, 90, 85, 80, 75, or 70 wt% of the non-solvent. In embodiments, the bore fluid comprises 1-35 wt%, or greater than 5, 10, 15, 20, 25, or 30 wt%, or less than 35, 30, 25, 20, 15, 10, or 5 wt% of the solvent with respect to the polybenzimidazole.
[046] The non-solvent with respect to the PBI is a solvent that does not appreciably dissolve PBI under temperatures and pressures used in the inventive methods. For example, the non-solvent is able to dissolve less than 10, 5, 1, 0.5, or 0.1 % of the weight of PBI that a similar volume of solvent is able to dissolve. Examples of non-solvents for PBI include water and alcohols such as methanol, ethanol, i-propanol, n-propanol, etc.
[047] By applying a liquid as a bore fluid, a phase transition can be induced and the fiber morphology near the inner surface can be controlled through phase inversion.
[048] The bath is filled with a non-solvent with respect to PBI. The non-solvent in the bath may the same, or may be different from, the non-solvent present in the bore fluid. The precipitation of PBI resulting from the polymeric solution entering the bath is referred to herein as quenching. The quenching of the polymeric solution and bore fluid creates the asymmetric hollow fiber having an annular shape and having first and second concentric layers as described herein. In some embodiments the annular shape of the hollow fiber is identical to the annular shape of the polymeric solution (i.e., surrounding the bore fluid) passing through the gap. In some embodiments, swelling or contracting other minor variations cause the annular shape of the hollow fiber to be non-identical to the annular shape of the polymeric solution in the gap, although the hollow fiber shape will nevertheless be derived from the annular shape of the polymeric solution in the gap.
[049] The gap comprises an atmosphere. The atmosphere may be air, a single gas such as nitrogen or argon, or any desired composition of gases. The length of the gap between the spinneret and the bath is referred to herein as the dropping distance. The dropping distance may be any length in the range 0.3-20 cm, such as greater than 0.3, 0.5, 1, 3, 5, 10, or 15 cm, or less than 20, 15, 10, 5, 3, or 1 cm. The relative lengths of the swelling and elongation regions will depend on a variety of factors such as the solution parameters, the atmosphere within the gap, and the like.
[050] The inventive methods result in the formation of asymmetric hollow fibers comprising a PBI material. The method may further include post-spinning procedures. For example, post-spinning procedures include washing and drawing the fiber.
Washing may be with a non-solvent or mixture of non-solvents for PBI, such as water, alcohol, glycol, or polyol solvents. Drawing can include any method for stretching the fibers, such as stretching though a double roller or stretching lengthwise using any appropriate method. In some embodiments such post-spinning procedures increase the mechanical strength of the fibers. Such increase in mechanical strength may be by at least 100, 150, or 200 %, and may refer to tensile strength or other measures of fiber strength.
[051] The asymmetric hollow fibers have a "donut" shape in cross-section. Thus the fiber comprises (in cross-section) a wall having a ring shape, wherein the wall comprises first and second concentric (and contacting) layers. The difference between the outer diameter of the ring and the inner diameter of the ring represents twice the thickness of the fiber wall. [052] The inventive hollow fibers are asymmetric in that they comprise first and second concentric layers, wherein the first layer is non-porous and contacts the second layer, and the second layer is porous. In some embodiments, the first layer forms an outer surface and the second layer forms an inner surface of the asymmetric hollow fiber. In other embodiments, the first layer forms an inner surface and the second layer forms an outer surface of the asymmetric hollow fiber. Because of the porosity of the second layer, the first layer is typically denser than the second layer. In embodiments, the first layer is at least 1.1, 1.3, 1.5, 2, 3, 4, or 5 times denser than the second layer.
[053] The thickness of the first and second layers is controlled by the length of the dropping distance and by the relative polarities of the solvent and non-solvent. In some embodiments, the first layer has a thickness in the range 0.1-10 μιτι, such as at least 0.1, 0.5, 1, 2, 3, 5, or 8 μιτι, or less than 10, 8, 5, 3, 2, 1, or 0.5 μιη. In some embodiments, the second layer has a thickness in the range of 10-500 μιτι, such as at least 10, 25, 50, 100, 150, 200, 250, or 300 μιη, or less than 500, 300, 250, 200, 150, 100, 50, or 25 μιη. In some embodiments, the relatively less dense second layer has a thickness that is at least 10, 20, 50, 100, or 500 times greater than the relatively more dense first layer. The thickness of the various layers is measured as a cross-section of the fiber.
[054] The transition region between the first and second layers may be very sharp, such as less than 0.5, 0.1, 0.05, or 0.01 times the thickness of the first layer. In the transition region, the fiber material transitions from porous to non-porous (i.e.
relatively low density to relatively high density). In some embodiments, the transition region is thicker, and porosity decreases gradually over a region having a thickness at least 0.5, 0.8, or 1 times the thickness of the first layer.
[055] In embodiments, the porous second layer has interconnected nanometer scale pores. For example, the pores have an average diameter in the range of 5-250 nm, or greater than 5, 25, 50, 100, 150, or 200 nm, or less than 250, 200, 150, 100, 50, or 25 nm. The pores may be spherical, partially spherical, or irregular in shape. The degree and size of pores in the second layer is determined in part by the polarities of the solvent and non-solvent used (which affects the solvent exchange mechanism for pore formation). Other factors include the bath solvent temperature and pressure, and the rate and extent of solvent evaporation within the gap.
[056] The dimensions of the annular spinneret hole, hollow fiber dimension, shear stress within a spinneret, dope flow rate, the polymer-to-bore volumetric flow rate ratio, and the take-up-to-initial velocity ratio (draw ratio) are the primary factors that determine the final fiber structure.
[057] In embodiments, the chemical composition of the first layer and the chemical composition of the second layer are the same. Thus, for example, the first and second layers are both made of the same PBI material selected from the materials described herein.
[058] In embodiments, the asymmetric hollow fiber is stable up to 400 °C. Thus, up to 400 °C, there is little or no degradation (i.e., less than 10, 5, 3, or 1 wt%) of the fiber material.
[059] The outer annular orifice of the tube-in-orifice spinneret has an outside diameter in the range 100-2000 μιη. Thus, the final asymmetric hollow fibers may have an outside diameter within the range of 100-2000 μιτι, such as greater than 100, 200, 300, 400, 500, 1000, or 1500 μιη, or less than 2000, 1500, 1000, 500, 400, 300, or 200 μιη. The inside diameter (i.e., the diameter of the cavity within the hollow fibers) will be determined by the outside diameter and the thickness of the first and second layers (and thus, for example, may be within the range 90-1990 μιη).
[060] The inventive asymmetric hollow fibers may be used to form a hollow fiber membrane (HFM). For example, the spinning procedure described herein may further comprise taking up the fiber at a rate of 1-100 meters/min to form a HFM.
[061] The membrane may be used in a method for separating H2 from a gas mixture comprising H2, C02, CO, and methane, the method comprising passing the gas mixture through the membrane.
[062] The membrane may be used in a method for removing impurities from a water solution, the method comprising passing the water solution through the membrane.
[063] PBI membranes can be sulfonated, for example, after fabrication of the hollow fiber using a dip-and-dry procedure.
[064] Unless otherwise indicated, the disclosure is not limited to specific procedures, materials, or the like, as such may vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting.
[065] As used in the specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to "a solvent" includes not only a single solvent but also a combination or mixture of two or more different solvents.
[066] The invention encompasses all combinations of recited particular and preferred embodiments. It is understood that the examples and embodiments described herein are for illustrative purposes only and that various modifications or changes in light thereof will be suggested to persons skilled in the art and are to be included within the spirit and purview of this application and scope of the appended claims. All
publications, patents, and patent applications cited herein, including citations therein, are hereby incorporated by reference in their entirety for all purposes.
Examples
[067] A Dope solution was prepared as follows: 18 wt % PBI dope and 2 wt % PVP (K16-18, Acros Organics, New Jersey) (a high molecular weight pore former with a molecular weight of 8000 daltons) in DMAc.
[068] A Bore fluid was prepared as follows: 75 to 90 wt% IPA and 5 to 25 wt% DMAc.
[069] The Coagulating bath was prepared containing 100% IPA.
[070] A strong non-solvent selected from water, isopropyl alcohol, methanol and their combinations are used as the bore fluid and the coagulation bath. The strong nonsolvent has the ability to coagulate the polymer solution at the exit of the spinneret; therefore, a thin membrane layer will be formed between the outer polymer solution, otherwise the fiber is easily broken and the polymer solution will go down as liquid drop under the force of gravitation. Inner bore fluid is a mixture of non-solvent and the solvent to avoid formation of membrane layer. The spinneret is fabricated with 1.2 mm outer diameter and 0.4 inner diameter. This dope solution contains 26 wt% PBI and 2 wt.% LiCl in Ndimethylacetamide (DMAc). Following specific compositions of dope solution, bore fluid and coagulation bath was used to fabricate asymmetric PBI hollow fiber
membrane with H2 permeance of 300 GPU with defect free selective gas separating layer at the shell side.
[071] High magnification pictures of fiber having a cross-section of 0.5 mm OD were taken. Similarly, high magnification pictures of fiber having a cross-section of 0.8 mm OD were taken. The images show porosity at the inner layer and a non-porous dense outer layer. [072] The dense layer provides the separation between the highly permeating H2 and low permeating C02 whereas the porous layer provides mechanical strength with low pressure drop for the passage of the permeating gas. The testing of the fabricated fiber showed that the H2 permeates more rapidly than C02 through the membrane. The permeance of H2 increases with increasing temperature whereas the permeance of C02 is relatively insensitive to temperature.
[073] The performance of prepared fibers was evaluated over 50 days, representing the performance over 1000 hours. The selectivity for H2/C02 improved with time increasing from 35 to 50, exceeding the design target of 40. Long-term performance evaluation data were obtained. The H2 permeance value remained at about 80 GPU (Gas Permeation Unit) throughout the test period. At the end of the 1000-h test period, the H2 permeance was measured to be 130 GPU at 250°C.
[074] H2/C02 was measured as a function of H2 permeance in GPU units at 150, 200, 225, and 250 °C. Both H2/C02 selectivity and H2 permeance increased with increasing temperature up to 225 °C. The ratio of H2/C02 increases whereas the H2 permeance decreases at 250 °C. This suggests a slight increase in the thickness of the dense layer. Permeance increases as selectivity decreases. Dense layer thicknesses were tested between 1 and 10 μιτι, and could be tested as low as 0.1 μιη.
[075] The presence of macro-voids is highly dope-specific and is dependent strongly on the non-solvent and solvent exchange rate during coagulation. The measured H2 permeance for a fiber containing macro-voids was in the range 100 to 200 GPU at room temperature but the H2/C02 selectivity was only 5. The presence of macro-voids also reduces the mechanical strength of the fiber.

Claims

What is claimed is:
1. A method for preparing an asymmetric hollow fiber, the method comprising:
(a) passing, through an outer annular orifice of a tube-in-orifice spinneret, a polymeric solution comprising: (i) 15-25 wt% of a polybenzimidazole; (ii) 1-5 wt% of a polymeric pore-forming material; and (iii) a solvent with respect to the
polybenzimidazole;
(b) passing, though an inner tube of the spinneret, a bore fluid comprising: (i) 65-99 wt. % of a non-solvent with respect to the polybenzimidazole; and (ii) 1-35 wt. % of a solvent with respect to the polybenzimidazole, wherein the bore fluid maintains the polymeric solution in an annular shape;
(c) dropping the polymeric solution and bore fluid through a gap, wherein the gap comprises an atmosphere and a dropping distance of 0.3 to 20 cm;
(d) quenching the polymeric solution and bore fluid in a bath to form an asymmetric hollow fiber having an annular shape and comprising first and second concentric layers, wherein the first layer contacts the second layer and is non-porous, and wherein the second layer is porous having pores in the range 5-250 nm.
2. The method of claim 1:
(a) comprising taking up the fiber into a fiber bundle at a rate of 1-100 meters/min to form a hollow fiber membrane;
(b) wherein the polymeric solution is stable against chemical degradation for at least 6 months within a temperature range of 15-25 °C;
(c) comprising post-spinning washing and drawing of the fiber;
(d) wherein the polybenzimidazole is sulfonated polybenzimidazole; or
(e) comprising any combination or subcombination of (a), (b), (c) and (d).
3. The method of claim 1, wherein the first layer forms an outer surface and the second layer forms an inner surface of the asymmetric hollow fiber.
4. The method of claim 1, wherein the first layer forms an inner surface and the second layer forms an outer surface of the asymmetric hollow fiber.
5. The method of claim 1, wherein the first layer has a thickness in the range 0.1-10 μιτι, and wherein the second layer has a thickness in the range of 10-500 μιη.
6. The method of claim 1, wherein the chemical composition of the first layer and the chemical composition of the second layer are the same.
7. The method of claim 1, wherein the outer annular orifice of the tube-in-orifice spinneret has an outside diameter in the range 100-2000 μιη.
8. The method of claim 1, wherein the thickness of the first and second layers is controlled by the length of the dropping distance and by the relative polarities of the solvent and non-solvent, and wherein the polybenzimidazole is sulfonated
polybenzimidazole.
9. The method of claim 1, wherein the first layer has a thickness in the range 0.1-10 μιτι, and wherein the second layer has a thickness in the range of 10-500 μιτι, and wherein the polymer precipitate partially solidifies during the dropping and fully solidifies during the quenching.
10. An asymmetric hollow fiber comprising first and second concentric layers forming a wall of the fiber, wherein:
the asymmetric hollow fiber comprises a polybenzimidazole material;
the first layer is non-porous and the second layer is porous having pores in the range 5-250 nm; and
the asymmetric hollow fiber has an outside diameter in the range 100-2000 μιη.
11. The asymmetric hollow fiber of claim 10, wherein:
(a) the polybenzimidazole is sulfonated polybenzimidazole; or
(b) the asymmetric hollow fiber is stable against chemical degradation up to 400
°C; or
(c) the first layer has a thickness in the range 0.1-10 μιτι, and wherein the second layer has a thickness in the range of 10-500 μιη.
12. The asymmetric hollow fiber of claim 10, wherein the first layer forms an outer surface and the second layer forms an inner surface of the asymmetric hollow fiber
13. A membrane comprising the asymmetric hollow fiber of claim 10.
14. A method for separating H2 from a gas mixture comprising H2, C02, CO, and methane, the method comprising passing the gas mixture through the membrane of claim 13.
15. A method for removing impurities from a water solution, the method comprising passing the water solution through the membrane of claim 13.
PCT/US2012/054033 2011-09-06 2012-09-06 Process for fabricating pbi hollow fiber asymmetric membranes for gas separation and liquid separation WO2013036693A2 (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
JP2014528706A JP6062945B2 (en) 2011-09-06 2012-09-06 Process for making PBI hollow fiber asymmetric membranes for gas and liquid separation
KR1020147005734A KR101951065B1 (en) 2011-09-06 2012-09-06 Process for fabricating pbi hollow fiber asymmetric membranes for gas separation and liquid separation
CN201280043088.4A CN103781536B (en) 2011-09-06 2012-09-06 Manufacture the method for the PBI doughnut asymmetric membrane being used for gas separaion and fluid separation applications
US14/190,100 US9321015B2 (en) 2011-09-06 2014-02-26 Process for fabricating PBI hollow fiber asymmetric membranes for gas separation and liquid separation

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US201161531448P 2011-09-06 2011-09-06
US61/531,448 2011-09-06

Related Child Applications (1)

Application Number Title Priority Date Filing Date
US14/190,100 Continuation US9321015B2 (en) 2011-09-06 2014-02-26 Process for fabricating PBI hollow fiber asymmetric membranes for gas separation and liquid separation

Publications (2)

Publication Number Publication Date
WO2013036693A2 true WO2013036693A2 (en) 2013-03-14
WO2013036693A3 WO2013036693A3 (en) 2013-05-02

Family

ID=47832775

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US2012/054033 WO2013036693A2 (en) 2011-09-06 2012-09-06 Process for fabricating pbi hollow fiber asymmetric membranes for gas separation and liquid separation

Country Status (4)

Country Link
JP (1) JP6062945B2 (en)
KR (1) KR101951065B1 (en)
CN (1) CN103781536B (en)
WO (1) WO2013036693A2 (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20230131140A (en) 2022-03-04 2023-09-12 한국화학연구원 Polybenzimidazole with protecting groups, preparation method of membrane using the same and the use thereof

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5683584A (en) * 1991-04-12 1997-11-04 Minntech Corporation Hollow fiber membranes and method of manufacture
US6015516A (en) * 1998-06-16 2000-01-18 National University Of Singapore Ultrathin high-performance hollow fiber membranes
US20030159980A1 (en) * 1999-03-19 2003-08-28 Barss Robert P. Solvent-resistant microporous polybenzimidazole membranes
US20040154986A1 (en) * 1999-01-29 2004-08-12 Kwok-Shun Cheng Skinned hollow fiber membrane and method of manufacture
KR100644366B1 (en) * 2005-11-08 2006-11-10 한국화학연구원 New spinning processes for asymmetric gas separation hollow fiber membranes

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA2300519C (en) 1999-03-19 2008-02-12 Bend Research, Inc. Solvent-resistant microporous polybenzimidazole membranes
WO2010077876A2 (en) 2008-12-16 2010-07-08 National University Of Singapore Chemically-modified polybenzimidazole membranous tubes
CN101642683B (en) * 2009-09-10 2012-05-02 苏州信望膜技术有限公司 Double-layer composite hollow fiber nano-filtration membrane and preparation method and special tool thereof
CN101844040A (en) * 2010-06-07 2010-09-29 苏州信望膜技术有限公司 Hollow fiber nanofiltration membrane and preparation method thereof

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5683584A (en) * 1991-04-12 1997-11-04 Minntech Corporation Hollow fiber membranes and method of manufacture
US6015516A (en) * 1998-06-16 2000-01-18 National University Of Singapore Ultrathin high-performance hollow fiber membranes
US20040154986A1 (en) * 1999-01-29 2004-08-12 Kwok-Shun Cheng Skinned hollow fiber membrane and method of manufacture
US20030159980A1 (en) * 1999-03-19 2003-08-28 Barss Robert P. Solvent-resistant microporous polybenzimidazole membranes
KR100644366B1 (en) * 2005-11-08 2006-11-10 한국화학연구원 New spinning processes for asymmetric gas separation hollow fiber membranes

Also Published As

Publication number Publication date
CN103781536A (en) 2014-05-07
WO2013036693A3 (en) 2013-05-02
CN103781536B (en) 2015-12-23
KR101951065B1 (en) 2019-04-22
KR20140070540A (en) 2014-06-10
JP2014527906A (en) 2014-10-23
JP6062945B2 (en) 2017-01-18

Similar Documents

Publication Publication Date Title
US9321015B2 (en) Process for fabricating PBI hollow fiber asymmetric membranes for gas separation and liquid separation
Kim et al. Microporous PVDF membranes via thermally induced phase separation (TIPS) and stretching methods
KR101462939B1 (en) Hydrophilic Polyvinylidene Fluoride Based Hollow Fiber Membrane and Preparing Method Thereof
KR101539608B1 (en) Polyvinylidene fluoride Hollow Fiber Membranes and Preparation Thereof
RU2569590C2 (en) Hollow-fibre membrane
KR20070113375A (en) Asymmetric poly(vinylidene fluoride) hollow fiber membranes and methods to make membranes
US10987846B2 (en) Thin film composite hollow fiber membranes for osmotic power generation
US20130049246A1 (en) Process for production of porous membrane
Ho et al. Fabrication of high-flux asymmetric polyethersulfone (PES) ultrafiltration membranes by nonsolvent induced phase separation process: Effects of H2O contents in the dope
KR101496376B1 (en) Hollow fiber type nanofiltration membrane and manufacturing method thereof
KR20150078245A (en) Hollow fiber type nanofiltration membrane having high ions removal capacity, and manufacturing method thereof
KR20130040620A (en) Preparation method of hollow fiber membrane with high mechanical properties made of hydrophilic modified polyvinylidenefluoride for water treatment
JP2005144412A (en) Polyketone hollow fiber membrane and manufacturing method of the same
WO2013036693A2 (en) Process for fabricating pbi hollow fiber asymmetric membranes for gas separation and liquid separation
Jayaweera et al. Process for fabricating PBI hollow fiber asymmetric membranes for gas separation and liquid separation
KR101025754B1 (en) Macrovoid free hollow fiber membrane and manufacturing method threrof
KR101331066B1 (en) Polyethersulfone hollow fiber membrane and method of manufacturing the same
CN113195082A (en) Porous membranes for high pressure filtration
CN113195081A (en) Porous membranes for high pressure filtration
KR20130040622A (en) The preparation method of hollow fiber membrane with high permeation using hydrophilized polyvinylidenefluoride for water treatment
KR101397842B1 (en) Polyvinylidene fluoride asymmetry-porous hollow fiber membrane and manufacturing method thereof
KR102426676B1 (en) Microfiber-based Membranes and Method for Preparing the Same
KR20130040625A (en) Polyvinylidenefluoride hollow fiber membrane with secondary barrier for water treatment and preparation thereof
JP2675197B2 (en) Manufacturing method of high strength and porous polysulfone hollow fiber membrane
KR20120007277A (en) Hollow fiber membrane of poly(ethylenechlorotrifluoroethylene) with enhanced water permeability and manufacturing method thereof

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 12830543

Country of ref document: EP

Kind code of ref document: A2

ENP Entry into the national phase

Ref document number: 20147005734

Country of ref document: KR

Kind code of ref document: A

ENP Entry into the national phase

Ref document number: 2014528706

Country of ref document: JP

Kind code of ref document: A

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 12830543

Country of ref document: EP

Kind code of ref document: A2