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WO2018131697A1 - Membrane de séparation de gaz - Google Patents

Membrane de séparation de gaz Download PDF

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Publication number
WO2018131697A1
WO2018131697A1 PCT/JP2018/000744 JP2018000744W WO2018131697A1 WO 2018131697 A1 WO2018131697 A1 WO 2018131697A1 JP 2018000744 W JP2018000744 W JP 2018000744W WO 2018131697 A1 WO2018131697 A1 WO 2018131697A1
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WIPO (PCT)
Prior art keywords
gas separation
gas
separation membrane
polyimide
carbon dioxide
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Ceased
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PCT/JP2018/000744
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English (en)
Japanese (ja)
Inventor
弘 江口
山中　一広
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Central Glass Co Ltd
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Central Glass Co Ltd
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Priority claimed from JP2017234224A external-priority patent/JP2018114491A/ja
Application filed by Central Glass Co Ltd filed Critical Central Glass Co Ltd
Publication of WO2018131697A1 publication Critical patent/WO2018131697A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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    • 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
    • B01D71/58—Other polymers having nitrogen in the main chain, with or without oxygen or carbon only
    • B01D71/62—Polycondensates having nitrogen-containing heterocyclic rings in the main chain
    • B01D71/64—Polyimides; Polyamide-imides; Polyester-imides; Polyamide acids or similar polyimide precursors
    • 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
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G73/00—Macromolecular compounds obtained by reactions forming a linkage containing nitrogen with or without oxygen or carbon in the main chain of the macromolecule, not provided for in groups C08G12/00 - C08G71/00
    • C08G73/06—Polycondensates having nitrogen-containing heterocyclic rings in the main chain of the macromolecule
    • C08G73/10—Polyimides; Polyester-imides; Polyamide-imides; Polyamide acids or similar polyimide precursors
    • 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
    • Y02P20/00—Technologies relating to chemical industry
    • Y02P20/151—Reduction of greenhouse gas [GHG] emissions, e.g. CO2

Definitions

  • the present invention relates to a gas separation membrane, a gas separation method using the same, and a gas separation apparatus.
  • a chemical absorption method in which an acidic gas is adsorbed to amines or the like has been used as a method for removing and purifying an acidic gas such as carbon dioxide (CO 2 ) from natural gas containing methane (CH 4 ).
  • the chemical absorption method is a method in which high-purity methane is efficiently obtained by adsorbing an acidic gas to an amine.
  • refining natural gas using the chemical absorption method requires a large gas separation device for the amount of purification, which requires construction costs, and costs for reusing the amine used as the absorbent in the purification process. There are problems such as taking.
  • the gas separation method using a gas separation membrane can use a small gas separation device for the gas throughput, and is advantageous for offshore plants of natural gas with a limited installation area.
  • the pressure of the natural gas at the time of sampling can be used as the driving force for passing the gas separation membrane.
  • a polymer such as polyimide is used as a material for the gas separation membrane.
  • the polyimide membrane exhibits excellent separation performance of carbon dioxide and methane at room temperature (about 20 ° C.).
  • the separation and purification of natural gas is generally performed continuously with the sampling gas, and is generally performed in the vicinity of 50 ° C., which is a higher temperature range.
  • the selectivity between carbon dioxide and methane decreases near 50 ° C., and high-purity methane tends not to be obtained.
  • Non-Patent Document 1 describes that the separation selectivity between carbon dioxide and methane by a polyimide membrane decreases as the temperature increases.
  • Natural gas is a fossil fuel containing a light hydrocarbon gas as a combustible gas.
  • hydrocarbon gas examples include methane, ethane, propane, butane, and pentane.
  • Natural gas contains nonflammable gases such as nitrogen, oxygen, carbon dioxide, water vapor, hydrogen sulfide gas, sulfurous acid gas, or sulfur oxide gas in addition to hydrocarbon gases. It is preferable to remove the flammable gas and separate and purify the combustible gas.
  • a gas separation membrane has a relationship in which gas separation selectivity and permeability at the time of gas separation are opposite to each other. Therefore, a polymer membrane having high permeability is inferior in separation selectivity.
  • a gas separation membrane having high gas permeability and excellent gas separation selectivity is required, and development of a polymer material having excellent gas separation performance compared to conventional polyimide membranes has been demanded. I'm in a hurry.
  • Patent Document 1 has a phenylenediamine skeleton, and at least one hydrogen atom on the phenylenediamine is a hexafluoroisopropanol group (2-hydroxy-1,1,1,3,3,3-hexafluoroisopropyl group;
  • a fluorine-containing polymerizable monomer substituted with —C (CF 3 ) 2 OH hereinafter sometimes referred to as HFIP group
  • Patent Documents 2 to 5 disclose gas separation membranes having a polyimide structure containing HFIP groups.
  • Patent Document 6 discloses a methane separation method capable of separating and purifying methane from biogas containing a high concentration of carbon dioxide with high efficiency, a methane separation device using the same, and a methane utilization system, and a gas separation membrane module Is used.
  • the permeability coefficient of carbon dioxide when separating natural gas is 10 Barrer or more, and the permeability coefficient ratio between carbon dioxide and methane (CO 2 permeability coefficient P CO2 / CH 4 permeability coefficient P CH4 ) exceeds 40
  • CO 2 permeability coefficient P CO2 / CH 4 permeability coefficient P CH4 exceeds 40
  • An object of the present invention is to provide a gas separation membrane having excellent gas separation performance, a gas separation method using the same, and a gas separation device. Specifically, a gas separation membrane excellent in removing carbon dioxide from natural gas and obtaining a gas containing high-concentration methane in a high temperature range of 35 ° C. or higher and 70 ° C. or lower, and gas using the same An object of the present invention is to provide a separation method and a gas separation apparatus. In particular, the permeability coefficient P CO2 of carbon dioxide when a gas containing carbon dioxide and methane is separated at a separation temperature of 50 ° C.
  • An object of the present invention is to provide a gas separation membrane having a gas separation performance with a CO 2 / CH 4 permeability coefficient P CH4 ) exceeding 40.
  • DSDA 4,4′-diphenylsulfonetetracarboxylic dianhydride
  • the present inventors have found that the gas separation membrane of the polyimide has a different permeability coefficient ratio between oxygen and nitrogen and can concentrate oxygen or nitrogen in a gas containing oxygen and nitrogen. Based on these findings, the present invention has been completed.
  • 1 Barrer 1 ⁇ 10 ⁇ 10 cm 3 (STP) ⁇ cm / sec ⁇ cm 2 ⁇ cmHg.
  • the present invention includes the following inventions 1 to 17.
  • a gas separation membrane comprising a polyimide having a repeating unit represented by formula (1).
  • R 1 is a divalent organic group represented by formula (2).
  • R 2 is a hydrogen atom, an alkyl group or a fluoroalkyl group, and a is an integer of 1 to 2
  • invention 4 The gas separation membrane according to inventions 1 to 3, wherein the polyimide has a weight average molecular weight of 20,000 or more and 500,000 or less.
  • invention 5 The gas separation membrane according to any one of inventions 1 to 4, wherein the polyimide heated at 50 ° C. or more and 400 ° C. or less is used.
  • invention 6 The gas separation membrane of inventions 1 to 5, wherein the gas to be separated is a gas containing at least carbon dioxide and methane.
  • invention 7 The gas separation membrane of invention 6 wherein the permeability coefficient of carbon dioxide at 50 ° C. and 150 kPa is 10 Barrer or more, and the permeability coefficient ratio (P CO2 / P CH4 ) between carbon dioxide and methane is 40 or more.
  • invention 8 The gas separation membrane of invention 6 or invention 7, wherein the gas containing carbon dioxide and methane is natural gas.
  • invention 10 A gas separation method for separating carbon dioxide from a gas containing carbon dioxide and methane using the gas separation membranes of the inventions 6 to 8.
  • invention 11 The gas separation method of Invention 9 or Invention 10, wherein gas separation is performed at 35 ° C. or more and 70 ° C. or less.
  • invention 12 A gas separation membrane module having the gas separation membrane of inventions 1 to 8.
  • invention 13 A gas separation device having the gas separation membrane of the inventions 1 to 8.
  • invention 14 The gas separation membrane of inventions 1 to 5, wherein the gas to be separated is a gas containing at least oxygen and nitrogen.
  • invention 16 A gas separation method for separating oxygen from a gas containing oxygen and nitrogen using the gas separation membranes of the inventions 14 to 15.
  • invention 17 A gas separation method for separating nitrogen from a gas containing oxygen and nitrogen using the gas separation membranes of the inventions 14 to 15.
  • a gas separation membrane having excellent gas separation performance at a separation temperature of 35 ° C. or higher and 70 ° C. or lower, a gas separation method and a gas separation apparatus using the same are obtained.
  • the gas separation performance is such that the permeability coefficient of carbon dioxide when separating gas containing carbon dioxide and methane is 10 Barrer or higher and the permeability coefficient ratio of carbon dioxide and methane (CO 2 permeability) (Coefficient / CH 4 permeability coefficient) exceeds 40, and it is excellent in removing carbon dioxide from natural gas and obtaining a gas containing a high concentration of methane.
  • CO 2 permeability coefficient and CO 2 / CH 4 permeability coefficient ratio measured in the gas permeability performance test (50 ° C. test ambient temperature) of the gas separation membranes obtained in the examples and comparative examples. It is a graph showing the relationship of a transmission coefficient.
  • the gas separation membrane of the present invention contains polyimide.
  • gas permeability is the solubility indicating how much gas dissolves into the membrane (hereinafter sometimes referred to as the solubility coefficient) and how fast the gas moves through the membrane (hereinafter referred to as the diffusion coefficient).
  • the permeability coefficient is expressed as the product of the solubility coefficient and the diffusion coefficient.
  • the temperature dependence of the CO 2 solubility coefficient and the CO 2 diffusion coefficient cancel each other, and as a result, it is presumed that the temperature dependence of the CO 2 permeability coefficient is low.
  • the phenylenediamine-derived skeleton having an HFIP group in the polyimide used for the gas separation membrane increases the free volume in the polyimide, thereby activating the permeation of CH 4 with a large dynamic molecular size into the membrane.
  • the temperature dependence of CH 4 is lowered, and the gas separation membrane has a free volume that is optimal for the selection of carbon dioxide and methane, resulting in a high carbon dioxide and methane permeability coefficient ratio.
  • the polyimide which the gas separation membrane of this invention contains has a repeating unit represented by General formula (1).
  • the repeating unit represented by formula (1) may be referred to as repeating unit (1)
  • the polyimide having the repeating unit represented by formula (1) may be referred to as polyimide (1).
  • R 1 is a divalent organic group represented by formula (2).
  • R 2 is a hydrogen atom, an alkyl group or a fluoroalkyl group, and a is an integer of 1 to 2
  • R 1 is a divalent organic group, and may have not only a linear structure but also an alicyclic, unsaturated, aromatic, or polycyclic structure with a carbon atom, or a heterocyclic structure.
  • Hydrogen atom, fluorine atom, chlorine atom, oxygen atom, sulfur atom or nitrogen atom may be contained. Further, some or all of the hydrogen atoms may be substituted with an alkyl group, a fluoroalkyl group, a carboxyl group, a hydroxy group, or a cyano group.
  • R 1 is preferably any one of the following divalent organic groups.
  • the polyimide (1) used for the gas separation membrane of the present invention is preferably a polyimide (1) having any one of the following repeating units.
  • polyimide (1) having the following repeating units.
  • the repeating unit (1) may be regularly arranged in the polyimide (1) or may be irregularly arranged.
  • the polyimide (1) contained in the gas separation membrane of the present invention may further have a repeating unit represented by the formula (3).
  • the repeating unit represented by the general formula (3) may be referred to as a repeating unit (3).
  • R 1 is a divalent organic group, and may have not only a linear structure but also an alicyclic, unsaturated, aromatic, or polycyclic structure with a carbon atom, or a heterocyclic structure.
  • Hydrogen atom, fluorine atom, chlorine atom, oxygen atom, sulfur atom or nitrogen atom may be contained. Further, some or all of the hydrogen atoms may be substituted with an alkyl group, a fluoroalkyl group, a carboxyl group, a hydroxy group, or a cyano group.
  • R 1 is preferably any one of the following organic groups.
  • R 3 is any tetravalent organic group represented by the following formula.
  • R 3 is preferably any organic group represented by the following formula.
  • the polyimide (1) used for the gas separation membrane of the present invention is preferably a polyimide having any of the following repeating units (3) in addition to the repeating unit (1).
  • polyimide (1) having the following repeating unit (3).
  • the abundance ratio of the repeating unit (1) and the repeating unit (3) is not particularly limited.
  • the weight average molecular weight (Mw) of the polyimide (1) contained in the gas separation membrane of the present invention is preferably from 20,000 to 500,000, particularly preferably from 30,000 to 200,000. If it is 20000 or more, a tough gas separation membrane can be obtained, and if it is 500,000 or less, it can be formed.
  • the weight average molecular weight is a value obtained by measuring by gel permeation chromatography (GPC) and converting to polystyrene using a standard polystyrene calibration curve.
  • Polyimide (1) can be obtained by reacting phenylenediamine represented by formula (4) with tetracarboxylic dianhydride represented by formula (5).
  • a and R 2 are each synonymous with a and R 2 of formula (2).
  • polyimide (A) or (B) phenylenediamine represented by formula (4) and tetracarboxylic dianhydride represented by formula (5) are subjected to condensation polymerization in an organic solvent to obtain a polyamic acid, and then the polyamic acid is dehydrated. The manufacturing method of the polyimide which obtains a polyimide (1) by making it ring-close and imidize.
  • a diamine other than that represented by formula (4) or a tetra other than that represented by formula (5) may be used as necessary to adjust the properties of the resulting polyimide.
  • Carboxylic dianhydride, or both, may be added.
  • the polyimide production method (A) is obtained by polycondensing a phenylenediamine represented by the formula (4) and a tetracarboxylic dianhydride represented by the formula (5) in an organic solvent.
  • an acid is obtained, and then the polyamic acid is dehydrated and cyclized and imidized to obtain polyimide (1).
  • the organic solvent to be used may be one that does not inhibit the polycondensation reaction for obtaining a polyamic acid from the phenylenediamine represented by the formula (4) and the tetracarboxylic dianhydride represented by the formula (5).
  • organic solvents include amide solvents, aromatic solvents, halogen solvents, lactone solvents, alcohol solvents, and glycol ether solvents. These organic solvents may be used alone or in combination of two or more.
  • amide solvent examples include N, N-dimethylformamide, N, N-dimethylacetamide, hexamethylphosphoric triamide, and N-methyl-2-pyrrolidone.
  • aromatic solvent examples include benzene, anisole, diphenyl ether, nitrobenzene, benzonitrile, and p-chlorophenol.
  • halogen solvent examples include chloroform, dichloromethane, 1,2-dichloroethane, and 1,1,2,2-tetrachloroethane.
  • lactone solvent examples include ⁇ -butyrolactone, ⁇ -valerolactone, ⁇ -valerolactone, ⁇ -caprolactone, ⁇ -caprolactone, and ⁇ -methyl- ⁇ -butyrolactone.
  • alcohol solvent examples include n-butyl alcohol.
  • glycol ether solvents include 2-methoxyethanol, 2-ethoxyethanol, and 2-butoxyethanol.
  • the reaction temperature in the polycondensation reaction for obtaining a polyamic acid from the phenylenediamine represented by the formula (4) and the tetracarboxylic dianhydride represented by the formula (5) is usually ⁇ 20 ° C. or higher and 80 ° C. or lower. Since the polycondensation reaction between diamine and tetracarboxylic dianhydride is a one-to-one reaction expressed in molar ratio, in the polycondensation reaction, the phenylenediamine represented by formula (4) and formula (5) It is preferable that the abundance ratio of the tetracarboxylic dianhydride represented by the formula is represented as a molar ratio of 1: 1.
  • the polyimide (1) is obtained by further dehydrating and ring-closing the polyamic acid obtained by the polymerization reaction to imidize.
  • Dehydration ring closure is a method in which the polyamic acid immediately after condensation polymerization is heated to 100 ° C. or higher and 350 ° C. or lower, or 0 ° C. or higher and 50 ° C. or lower, pyridine, triethylamine, etc.
  • the base and acetic anhydride of each are imidized by adding 2 molar equivalents or more and 10 equivalents or less, and the polyimide (1) solution can be obtained.
  • the obtained polyimide (1) solution may be directly used for the production of a gas separation membrane described later, or may be concentrated or diluted, or an organic solvent or the like is removed from the polyimide (1) solution.
  • polyimide (1) itself may be obtained.
  • the gas separation membrane of the present invention is particularly excellent in carbon dioxide permeability and excellent in separation of a mixed gas containing carbon dioxide and hydrocarbons, particularly a mixed gas containing carbon dioxide and methane.
  • a gas separation membrane according to an embodiment of the present invention is a gas separation membrane for separating carbon dioxide or methane from a gas containing at least carbon dioxide and methane.
  • the gas separation membrane of the present invention is excellent in separation of oxygen and nitrogen, and is useful as a gas separation membrane for separating oxygen from a gas (for example, air) containing oxygen and nitrogen.
  • the gas separation membrane of the present invention contains at least polyimide (1).
  • the content of the polyimide (1) is preferably 40% by mass or more, more preferably 80% by mass or more, and particularly preferably only the polyimide (1).
  • various polymer compounds other than polyimide (1) may be contained as components.
  • examples of such a polymer compound include acrylic resins, silicone resins, polyurethane resins, polyamide resins, polyimide resins, polyamideimide resins, polyester resins, epoxy resins, phenol resins, bismaleimide resins, polycarbonate resins, polyvinyl butyral resins, polyvinyl resins.
  • Formal resin, vinyl resin, rubber, wax, shellac and other natural resins can be used. Also. Two or more of these may be used in combination.
  • the temperature when heating (baking) the polyimide (1) contained in the gas separation membrane of the present invention is preferably 50 ° C. or higher and 400 ° C. or lower, more preferably 100 ° C. or higher and 325 ° C. or lower. In particular, it is preferably 150 ° C. or higher and 320 ° C. or lower.
  • the heating temperature is lower than 50 ° C., it is difficult to obtain a dense separation layer as a gas separation membrane.
  • the heating temperature is higher than 400 ° C., there is a concern about thermal decomposition of polyimide (1), and it is used as a gas separation membrane. It is difficult to obtain a sufficient mechanical strength.
  • the heating time is preferably 30 minutes or longer and 24 hours or shorter, more preferably 1 hour or longer and 12 hours or shorter.
  • Performance gas permeability coefficient of the gas separation membrane especially CO 2 permeability coefficient under the conditions of 150 kPa, 50 ° C.
  • CO 2 permeability coefficient is preferably 10 barrels (Barrer) above.
  • the permeability coefficient ratio between carbon dioxide and methane is preferably 40 or more, particularly preferably 42 or more, and further preferably 45 or more.
  • the gas permeability coefficient is a CO 2 permeability coefficient of 10 barr or more, and the permeability coefficient ratio between carbon dioxide and methane (CO 2 permeability coefficient / CH 4 permeability coefficient). Is more preferably 45 or more, because it is a gas separation membrane that satisfies both high permeability and very excellent gas selectivity at the same time, and is particularly preferable.
  • the gas separation performance of the gas separation membrane of the present invention is that the CO 2 permeability coefficient is 10 barrels or more at 50 ° C., and the permeability coefficient ratio (CO 2 permeability coefficient / CH 4 permeability coefficient) between carbon dioxide and methane is 40 or more. It is.
  • the CO 2 permeability coefficient is 10 Barrer or more under the conditions of 150 kPa and 50 ° C., and the permeability coefficient ratio (CO 2) between carbon dioxide and methane. (2 permeability coefficient / CH 4 permeability coefficient) of 40 or more can be obtained, and high carbon dioxide permeability and gas selectivity can be satisfied simultaneously.
  • the gas separation membrane of the present invention may be a symmetric membrane comprising a dense layer or an asymmetric membrane comprising a dense layer and a porous layer.
  • the dense layer has a different permeation rate depending on the gas species and serves to separate the gas mixture, while the porous layer can serve as a support for maintaining the membrane shape.
  • the shape of the asymmetric membrane may be, for example, a flat membrane shape or a hollow fiber membrane shape.
  • the thickness is preferably 500 nm or more and 1 mm or less, more preferably 10 ⁇ m or more and 100 ⁇ m or less. If it is thinner than 500 nm, the film formation is not easy and it is easy to break, and if it is thicker than 1 mm, the gas hardly penetrates.
  • the thickness of the dense layer is preferably 10 nm or more and 10 ⁇ m or less, and more preferably 30 nm or more and 1 ⁇ m or less. If it is thinner than 10 nm, the film formation is not easy and it is easy to break, and if it is thicker than 10 ⁇ m, the gas hardly penetrates.
  • the layer thickness of the porous layer is preferably 5 ⁇ m or more and 2 mm or less, more preferably 10 ⁇ m or more and 500 ⁇ m or less. If it is thinner than 5 ⁇ m, it is not easy to form a film and it is easy to break.
  • the outer side is preferably a dense layer and the inner side is preferably a porous layer, and the inner diameter is preferably 10 ⁇ m or more and 4 mm or less, more preferably 20 ⁇ m or more.
  • the outer diameter which is 1 mm or less, is preferably 30 ⁇ m or more and 8 mm or less, and more preferably 50 ⁇ m or more and 1.5 mm or less.
  • the inner diameter is less than 10 ⁇ m and the outer diameter is less than 30 ⁇ m, it is difficult to produce a hollow fiber membrane, and when the inner diameter is less than 1 mm and the outer diameter is less than 8 mm, it is not suitable for practical use as a hollow fiber membrane-shaped gas separation membrane.
  • the gas separation membrane of the present invention is a solution in which polyimide (1) is dissolved in an organic solvent, and is usually used for spin coating, spray coating, flow coating, impregnation coating, brush coating, etc. on a substrate. After coating by the method, it can be produced by forming or forming the film as it is.
  • the kind of organic solvent should just be what melt
  • the kind of organic solvent shown by the manufacturing method of the polyimide (1) of (A) is used. Can do. Moreover, you may use the solution of the said polyimide (1) used with the manufacturing method of the polyimide of (A).
  • the obtained gas separation membrane is preferably heated at a temperature of 50 ° C. or more and 400 ° C. or less after film formation or at the time of molding.
  • the solution of the polyamic acid obtained by the manufacturing method of the polyimide (1) of (A) is applied on a substrate, and the organic solvent is volatilized by heating at a heating temperature of 50 ° C. or more and 400 ° C. or less.
  • the dehydration ring-closure reaction is allowed to proceed to form a polyimide (1) membrane, which can be used as the gas separation membrane of the present invention.
  • the concentration of the polyimide (1) or the polyamic acid that is a precursor thereof in the solution is preferably 5% by mass or more and 50% by mass or less, and more preferably 10% by mass or more and 40% by mass or less.
  • the solution to be applied is a solution of polyimide (1) or polyamic acid poured into a poor solvent to precipitate, collect and dry the polyimide (1) polyamic acid, and then re-dissolved in an organic solvent. It may be used.
  • the substrate on which the polyimide (1) solution or the polyamic acid solution that is a precursor thereof is applied includes glass, silicon wafer, metal, metal oxide, ceramics, or resin. Can do.
  • a symmetrical membrane as the gas separation membrane of the present invention
  • a substrate such as a glass substrate using a spin coater or applicator
  • air By heating in a dry gas such as nitrogen or argon, the fired body is obtained through evaporation of the organic solvent and the cyclization dehydration reaction, and then the fired body is peeled off from the substrate.
  • a dry gas such as air, nitrogen, or argon It is obtained by peeling from the base material after obtaining a fired body by evaporating the organic solvent by heating in.
  • a solution of polyimide (1) is placed in a pressure vessel and is compatible with an organic solvent in the solution from its discharge port.
  • the polyimide is discharged into a bath filled with a poor solvent that does not dissolve, and the solvent present in the vicinity of the surface of the obtained polyimide film is evaporated in the air to form a dense layer on the surface side.
  • a method of forming the porous layer can be exemplified.
  • water or a mixed solution of water and an organic solvent is preferably used as the poor solvent.
  • the composition of this mixed solution is such that when a mixed solution of water and an organic solvent is used, water is 30% by mass or more and 90% by mass or less, preferably 40% by mass or more and 80% by mass with respect to the total mass of the mixed solution % Or less is preferably included.
  • the organic solvent include alcohol solvents and ketone solvents.
  • the alcohol solvent examples include methanol, ethanol, and isopropanol.
  • the ketone solvent examples include acetone, methyl ethyl ketone, diethyl ketone, and diethyl ketone.
  • a coating liquid containing polyimide (1) is applied on a porous support (porous support) to form a gas separation layer.
  • content of the polyimide (1) in a coating liquid is not specifically limited, It is preferable that it is 0.1 to 30 mass%, and it is especially 0.3 to 10 mass% especially. preferable. If the content of the polyimide (1) is too low, it is not preferable because it penetrates into the porous region when a film is formed on the support and a defect occurs on the surface of the separation layer. On the other hand, if the content is too high, the porous portion is filled at a high concentration, the separation layer is also thickened, and the permeability may be lowered.
  • the composite film By adjusting the molecular weight, structure, and solution viscosity of the polyimide (1), the composite film can be appropriately produced.
  • another layer such as a siloxane compound may be present between the polyimide (1) and the porous support layer in order to smooth the surface of the support layer.
  • porous support materials include polyolefin resins such as polyethylene and polypropylene, fluorine-containing resins such as polytetrafluoroethylene, polyvinyl fluoride, and polyvinylidene fluoride, polystyrene, cellulose acetate, polyurethane, polyacrylonitrile, polyphenylene oxide, and polysulfone. And various resins such as polyethersulfone, polyimide, polyamide, and polyamideimide.
  • Gas Separation Method uses a gas separation membrane containing the polyimide (1) of the present invention. This is a method for separating a specific kind of gas from a gas containing at least two kinds of gases.
  • the gas separation method of the present invention exhibits particularly excellent performance when the gas contains an acidic gas such as carbon dioxide.
  • the gas separation method of the present invention is preferably used for separation of a gas containing carbon dioxide and hydrocarbons, particularly a gas containing carbon dioxide and methane, because the gas separation membrane of the present invention is particularly excellent in carbon dioxide permeability.
  • carbon dioxide or methane can be suitably separated with good selectivity from a gas containing carbon dioxide and methane.
  • a CO 2 permeability coefficient of 10 barrels or more is obtained at 50 ° C., and a permeability coefficient ratio (CO 2 permeability coefficient / CH 4 permeability coefficient) between carbon dioxide and methane is 40 or more. can get.
  • a CO 2 permeability coefficient of 10 barr or more and a permeability coefficient ratio of carbon dioxide and methane (150 bar, 50 ° C.) CO 2 permeability coefficient / CH 4 permeability coefficient) of 40 or more can be obtained, and high carbon dioxide permeability and gas selectivity can be satisfied at the same time.
  • a gas containing carbon dioxide and methane, particularly natural gas at 35 ° C. or higher and 70 ° C. or lower. More preferably, it is 40 degreeC or more and 60 degrees C or less. More preferably, it is 45 degreeC or more and 55 degrees C or less.
  • gas Although the gas which the gas separation membrane of this invention isolate
  • the abundance ratio of carbon dioxide with respect to the total amount of gas including carbon dioxide and methane is preferably 1% or more and 80% or less, more preferably 5% or more and 60% or less, and more preferably expressed in mass%. Is 7% or more and 50% or less.
  • the type of gas other than carbon dioxide and methane is not particularly limited, but other than hydrogen, helium, carbon monoxide, hydrogen sulfide, oxygen, nitrogen, ammonia, sulfur oxide (SOx), nitrogen oxide (NOx), and methane And hydrocarbons, unsaturated hydrocarbons, perfluoro compounds and the like.
  • hydrocarbons other than methane ethane, propane, butane or pentane can be exemplified
  • unsaturated hydrocarbons ethylene and propylene can be exemplified.
  • Tetrafluoroethane can be raised as the perfluoro compound.
  • gas to be separated by the gas separation membrane of the present invention include natural gas, which is effective for separating and purifying hydrocarbons, which are combustible gas components, by separating incombustible gas contained in natural gas. Can be used.
  • gas separated by the gas separation membrane of the present invention include biogas, and methane, which is a low-permeability gas, is preferably used for separation and purification from biogas containing methane and carbon dioxide. Can do.
  • the gas to be separated by the gas separation membrane of the present invention include a mixed gas obtained by an oil recovery enhancement method (EOR). From a mixed gas containing methane and carbon dioxide, a low permeability gas can be used. Certain methane can be suitably used for separation and purification. Further, the separated and recovered carbon dioxide can be used as a drop for EOR gas.
  • EOR oil recovery enhancement method
  • Gas Separation Device The gas separation membrane of the present invention can be used in a gas separation device as a means for separating and recovering or purifying gas.
  • the gas separation membrane of the present invention can be suitably used as a gas separation membrane module by being housed in a housing.
  • the gas separation membrane module include a spiral type, a hollow fiber membrane type, a pleat type, a tubular type, and a plate & frame type.
  • gas separation membrane of the present invention may be used as a gas separation membrane module, for example, in a gas separation / recovery device by a membrane / absorption hybrid method used in combination with an absorbing solution described in Patent Document 6.
  • Example 1 [Production of gas separation membrane made of polyimide (A)] ⁇ Preparation of polyimide (A)> 20.0 g (73 mmol) of HFIP-pPD and 26.1 g (73 mmol) of DSDA represented by the following formula were added to a 500-mL three-necked flask equipped with a nitrogen introduction tube and a stirring blade, and dimethylacetamide (73 mmol) as a solvent was further added. After adding 85 g of DMAc), the mixture was stirred at room temperature (20 ° C.) under a nitrogen atmosphere to obtain a reaction solution.
  • Mw is a weight average molecular weight and Mn is a number average molecular weight.
  • polyimide (P1) represented by the following formula was prepared by filtration under pressure.
  • the DMAc solution of the polyimide (P2) shown below was prepared by carrying out pressure filtration.
  • the DMAc solution of the polyimide (P3) shown below was prepared by carrying out pressure filtration.
  • the DMAc solution of the polyimide (P5) shown in the following reaction formula was prepared by carrying out pressure filtration.
  • the DMAc solution of the polyimide (P6) shown below was prepared by carrying out pressure filtration.
  • the DMAc solution of the polyimide (P7) shown below was prepared by carrying out pressure filtration.
  • the permeability coefficient ratio is an indicator of gas selectivity.
  • Table 1 shows the methane permeability coefficient, the carbon dioxide permeability coefficient, and the permeability coefficient measured at 35 ° C., 50 ° C. or 70 ° C. using the gas separation membranes prepared in Examples 1 to 3 and Comparative Examples 1 to 7 above. The ratio (CO 2 permeability coefficient / CH 4 permeability coefficient) is shown.
  • the gas separation performance of the gas separation membrane is greater for the gas of methane and carbon dioxide, the greater the permeability coefficient of carbon dioxide, the better the gas throughput per unit time, and the greater the permeability coefficient ratio, the greater the ratio of methane and carbon dioxide. Excellent separation performance.
  • the gas separation membrane of the present invention containing the HFIP group and the polyimide having the structure derived from phenylenediamine or the structure derived from DSDA prepared in Examples 1 to 3 was compared with Comparative Example 1 and Comparative Example 1.
  • the permeation coefficient ratio is large and the separation performance of methane and carbon dioxide is excellent in a 50 ° C. measurement environment. It was.
  • the gas separation membranes prepared in Examples 1 to 3 and including the polyimide having the structure derived from HFIP group and phenylenediamine and the structure derived from DSDA have the structures derived from HFIP group and DSDA in Comparative Examples 3 and 4.
  • the permeability coefficient ratio was large at 35 ° C. and 50 ° C., and the separation performance of methane and carbon dioxide was excellent.
  • the gas separation membranes prepared in Examples 1 to 3 have a HFIP group of Comparative Example 5 and are 35% more than the gas separation membrane containing polyimide not having a structure derived from DSDA and a structure derived from phenylenediamine.
  • the permeability coefficient ratio was large, and the separation performance of methane and carbon dioxide was excellent.
  • the gas separation membranes prepared in Examples 1 to 3 are gas separations containing polyimide prepared in Comparative Example 6 or Comparative Example 7 having a structure derived from HFIP groups and phenylenediamine and not having a structure derived from DSDA. Compared with the membrane, the permeability coefficient ratio was large at 35 ° C. and 50 ° C., and the separation performance of methane and carbon dioxide was excellent.
  • the gas separation membrane prepared in Example 1 is compared with the gas separation membrane prepared in Comparative Example 3, which includes a polyimide having a structure derived from HFIP group and DSDA and not having a structure derived from phenylenediamine.
  • the permeability coefficient ratio was large and the separation performance of methane and carbon dioxide was excellent.
  • the gas separation membrane of the present invention containing the polyimide having both the structure derived from HFIP group and phenylenediamine and the structure derived from DSDA prepared in Examples 1 to 3 is used when carbon dioxide is separated from natural gas by a gas separation membrane.
  • the carbon dioxide removal ability is superior to that of the conventional gas separation membrane, and high-purity methane can be obtained without loss of methane in the separation process.
  • nitrogen gas (N 2 ) was used instead of oxygen gas (0 2 ), and the permeability coefficient of nitrogen gas (N 2 ) was measured in the same manner. From the measured permeability coefficients of oxygen gas (0 2 ) and nitrogen gas (N 2 ), the permeability coefficient ratio of nitrogen gas (N 2 and oxygen gas (0 2 )) (nitrogen gas (N 2 ) / oxygen gas (0 2) ) Transmission coefficient). The permeability coefficient ratio is an indicator of gas selectivity.
  • Table 2 shows the oxygen permeability coefficient, nitrogen permeability coefficient, and permeability coefficient ratio (O 2) measured at 35 ° C. or 50 ° C. using the gas separation membranes prepared in Examples 1 to 3 and Comparative Examples 5 to 7 above. Transmission coefficient / N 2 transmission coefficient).
  • the oxygen concentration of air can be increased and a gas having a high oxygen concentration can be obtained.

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Health & Medical Sciences (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Organic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Analytical Chemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Separation Using Semi-Permeable Membranes (AREA)

Abstract

L'invention concerne une membrane de séparation de gaz qui contient un polyimide qui a une unité récurrente représentée par la formule (1). Ladite membrane de séparation de gaz présente d'excellentes performances de séparation de gaz dans une plage de température de séparation comprise entre 35°C et 70°C (inclus), et présente des performances de séparation particulièrement excellentes pour le CO2 et le CH4. Formule (1) (Dans la formule (1), R1 représente un groupe organique divalent représenté par la formule (2).) Formule (2) (Dans la formule (2), R2 représente un atome d'hydrogène, un groupe alkyle ou un groupe fluoroalkyle; et a représente un nombre entier de 1 à 2.
PCT/JP2018/000744 2017-01-16 2018-01-15 Membrane de séparation de gaz Ceased WO2018131697A1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
JP2017004794 2017-01-16
JP2017-004794 2017-03-09
JP2017234224A JP2018114491A (ja) 2017-01-16 2017-12-06 気体分離膜
JP2017-234224 2017-12-06

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004359860A (ja) * 2003-06-05 2004-12-24 Ube Ind Ltd 微細貫通パスを有するポリイミド多孔質膜及びその製造方法
JP2016137484A (ja) * 2015-01-26 2016-08-04 セントラル硝子株式会社 気体分離膜
JP2016175000A (ja) * 2015-03-18 2016-10-06 宇部興産株式会社 ポリイミドガス分離膜、及びガス分離方法
JP2018001118A (ja) * 2016-07-05 2018-01-11 セントラル硝子株式会社 気体分離膜

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004359860A (ja) * 2003-06-05 2004-12-24 Ube Ind Ltd 微細貫通パスを有するポリイミド多孔質膜及びその製造方法
JP2016137484A (ja) * 2015-01-26 2016-08-04 セントラル硝子株式会社 気体分離膜
JP2016175000A (ja) * 2015-03-18 2016-10-06 宇部興産株式会社 ポリイミドガス分離膜、及びガス分離方法
JP2018001118A (ja) * 2016-07-05 2018-01-11 セントラル硝子株式会社 気体分離膜

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