Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
  • B01D53/22—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
  • 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
  • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
  • B01D61/38—Liquid-membrane separation
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D67/00—Processes specially adapted for manufacturing semi-permeable membranes for separation processes or apparatus
  • B01D67/0039—Inorganic membrane manufacture
  • B01D67/0067—Inorganic membrane manufacture by carbonisation or pyrolysis
• • 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
  • B01D69/10—Supported membranes; Membrane supports
  • B01D69/106—Membranes in the pores of a support, e.g. polymerized in the pores or voids
• • 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
  • B01D69/10—Supported membranes; Membrane supports
  • B01D69/108—Inorganic support material
• • 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
  • B01D69/1213—Laminated layers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
  • B01D69/14—Dynamic membranes
  • B01D69/141—Heterogeneous membranes, e.g. containing dispersed material; Mixed matrix membranes
  • B01D69/142—Heterogeneous membranes, e.g. containing dispersed material; Mixed matrix membranes with "carriers"
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • 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
  • B01D69/147—Heterogeneous membranes, e.g. containing dispersed material; Mixed matrix membranes containing embedded adsorbents
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D71/00—Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
  • B01D71/02—Inorganic material
  • B01D71/021—Carbon
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2256/00—Main component in the product gas stream after treatment
  • B01D2256/24—Hydrocarbons
  • B01D2256/245—Methane
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2257/00—Components to be removed
  • B01D2257/50—Carbon oxides
  • B01D2257/504—Carbon dioxide
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2325/00—Details relating to properties of membranes
  • B01D2325/02—Details relating to pores or porosity of the membranes
  • B01D2325/022—Asymmetric membranes
  • B01D2325/023—Dense layer within the membrane
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2325/00—Details relating to properties of membranes
  • B01D2325/12—Adsorbents being present on the surface of the membranes or in the pores
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2325/00—Details relating to properties of membranes
  • B01D2325/28—Degradation or stability over time
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2325/00—Details relating to properties of membranes
  • B01D2325/30—Chemical resistance
• • 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
  • B01D69/08—Hollow fibre membranes
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02C—CAPTURE, STORAGE, SEQUESTRATION OR DISPOSAL OF GREENHOUSE GASES [GHG]
  • Y02C20/00—Capture or disposal of greenhouse gases
  • Y02C20/40—Capture or disposal of greenhouse gases of CO2

Definitions

• the present invention relates to a fluid separation membrane.
• Membrane separation is used as a method for selectively separating and purifying specific components from various mixed gases and liquids.
• Membrane separation methods are attracting attention because they are energy-saving compared to other fluid separation methods such as distillation.
• fluid separation membranes made of carbon for example, Patent Document 1
• fluid separation membranes made of polymer for example, Patent Document 2
• the present invention has been made in view of the above-described conventional situation, and an object thereof is to provide a fluid separation membrane capable of maintaining high separation performance for a long period of time.
• the present invention for solving the above problems is a fluid separation membrane having a separation layer composed of a dense layer, wherein a monocyclic or bicyclic aromatic compound that is liquid or solid at 16 ° C. and atmospheric pressure is 2 to
• the fluid separation membrane is formed by adsorbing 10,000 ppm and 10 to 250,000 ppm of water.
• the fluid separation membrane in the present invention (hereinafter sometimes simply referred to as “separation membrane”) is a separation membrane having a dense layer, and the dense layer functions as a substantial fluid separation layer.
• the material of the dense layer is not particularly limited, and general inorganic materials and polymer materials can be applied. However, the plasticization, swelling, and dimensional change of the aromatic compound that is the adsorption component of the fluid separation membrane of the present invention are suppressed.
• an inorganic material is preferable.
• the inorganic material is not particularly limited, but ceramics such as silica and zeolite, and carbon are preferably used. Among them, carbon is preferably used because of its high resistance to water, which is an adsorption component of the fluid separation membrane of the present invention.
• the carbon component ratio is preferably 60 to 95% by weight. If it is 60% by weight or more, the heat resistance and chemical resistance of the fluid separation membrane tend to be improved.
• the carbon component of the dense layer is more preferably 65% by weight or more. Further, when the ratio of the carbon component of the dense layer is 95% by weight or less, flexibility is generated, the bending radius is reduced, and the handleability is improved.
• the carbon component of the dense layer is more preferably 85% by weight or less.
• the carbon component ratio is the weight fraction of the carbon component when the total of the carbon, hydrogen and nitrogen components measured by the organic elemental analysis method is 100%.
• the entire separation membrane is quantitatively determined. It may be a value.
• the parts other than the dense layer of the fluid separation membrane may be made of the same material as the dense layer, or may be made of a different material. It is preferable from the viewpoint of improving stability.
• a preferable form of the fluid separation membrane of the present invention includes a form in which a dense layer is formed on the surface of a support having a porous structure from the viewpoint of pressure resistance and strength.
• the material of the support is not particularly limited, and is not particularly limited, such as an inorganic material or a polymer material.
• the aromatic compound that is the adsorption component of the fluid separation membrane of the present invention a viewpoint of suppressing structural changes and dimensional changes with respect to water. Therefore, carbon is preferably used.
• the porous structure of the support is preferably a three-dimensional network structure.
• the three-dimensional network structure is a structure consisting of branch portions and pores (voids) that are three-dimensionally continuous. Scanning electrons are taken from a cross section of a sample that has been sufficiently cooled in liquid nitrogen with tweezers. When the surface is observed with a microscope, the structure can be confirmed by the fact that the branch portion and the void portion are continuous. Having a three-dimensional network structure has the effect that the branches support the entire structure and disperse the stress throughout the entire structure, so it has high resistance to external forces such as compression and bending, and compressive strength and compression ratio strength Can be improved. Further, since the gap is three-dimensionally communicated, it has a role as a flow path for supplying or discharging a fluid such as gas or liquid.
• a co-continuous porous structure in which the branches and pores (voids) of the skeleton are continuously intertwined in a three-dimensional manner is particularly preferable. Having a bicontinuous porous structure can be confirmed by continually intertwining the branches and voids of the skeleton when the surface of the section cut in the same manner as described above is observed with a scanning electron microscope.
• a structure in which straight pipe (cylindrical) holes are opened from the front side to the back side of the membrane is a three-dimensional network structure, but is not included in the co-continuous porous structure because the branches and voids are not intertwined. Absent.
• the average diameter of the pores of the porous structure of the support is preferably 30 nm or more because pressure loss is reduced and fluid permeability is improved, and 100 nm or more is more preferable. Moreover, when the average diameter is 5,000 nm or less, the effect of supporting portions other than the pores to support the entire porous structure is improved and the compressive strength is increased, and 2,500 nm or less is more preferable.
• the average diameter of the porous structure is a measured value obtained by measuring the pore size distribution of the fluid separation membrane by the mercury intrusion method. In the mercury intrusion method, pressure is applied to pores of a porous structure to infiltrate mercury, and the pore volume and specific surface area are determined from the pressure and the amount of mercury that is intruded.
• the pore diameter obtained from the relationship between the pore volume and the specific surface area is calculated.
• a pore diameter distribution curve of 5 nm to 500 ⁇ m can be obtained. Since the dense layer has substantially no pores, the average diameter of the pores measured using the entire separation membrane as a sample can be regarded as substantially the same as the average diameter of the pores having a porous structure.
• the porous structure of the support preferably has a structural period, and the structural period is preferably 10 to 10,000 nm.
• a porous structure having a structural period indicates that the uniformity of the porous structure is high, means that the thickness of the skeleton and the pore size are uniform, and means that high compressive strength is easily obtained.
• the structural period is 10,000 nm or less, the skeleton and pores have a fine structure, and the compressive strength is improved.
• the structural period of the porous structure is more preferably 5,000 nm or less, and further preferably 3,000 nm or less.
• the structural period of the porous structure is more preferably 100 nm or more, and further preferably 300 nm or more.
• the structural period of the porous structure is calculated from the scattering angle 2 ⁇ at the position of the peak top of the scattering intensity obtained by making X-rays incident on the porous structure and scattering at a small angle.
• the structure period is large and small angle scattering may not be observed.
• the structural period is obtained by X-ray computed tomography (X-ray CT). Specifically, after performing a Fourier transform on a three-dimensional image photographed by X-ray CT, the two-dimensional spectrum is averaged to obtain a one-dimensional spectrum. The characteristic wavelength corresponding to the position of the peak top in the one-dimensional spectrum is obtained, and the structural period is calculated as its reciprocal.
• the uniformity of the porous structure can be determined by the half width of the intensity peak of the X-ray scattering intensity. Specifically, X-rays are incident on the porous structure of the support, and the smaller the half-value width of the obtained scattering intensity peak, the higher the uniformity.
• the half width of the peak is preferably 5 ° or less, more preferably 1 ° or less, and further preferably 0.1 ° or less.
• the half-width of the peak in the present invention means that the peak apex is point A, a straight line parallel to the vertical axis of the graph is drawn from point A, and the intersection of the straight line and the spectrum base line is point B , The width of the peak at the midpoint C of the line segment connecting points A and B. Moreover, the width of the peak here is the length between the intersections of the straight line passing through the point C and the scattering curve parallel to the baseline.
• the specific surface area of the separation membrane is preferably 10 to 1,500 m 2 / g or more.
• the specific surface area is 10 m 2 / g or more, the area capable of acting on the adsorption of the aromatic compound or water is increased, and higher durability can be obtained, and is preferably 20 m 2 / g or more. Preferably, it is more preferably 50 m 2 / g or more.
• the specific surface area is 1,500 m 2 / g or less, the film strength is improved and the handleability is excellent, which is preferable, more preferably 1,000 m 2 / g or less, and 500 m 2 / g or less. Is more preferable.
• the specific surface area in the present invention can be calculated based on the BET equation by measuring the adsorption isotherm by adsorbing and desorbing nitrogen on the fluid separation membrane in accordance with JISR 1626 (1996).
• the shape of the fluid separation membrane of the present invention is not particularly limited, such as a fiber shape or a film shape, but a fiber shape is more preferable from the viewpoint of high filling efficiency, high separation efficiency per volume, and excellent handleability.
• the fiber shape refers to those having a ratio of length L to diameter D (aspect ratio L / D) of 100 or more.
• the fiber-shaped separation membrane will be described.
• the shape of the fiber cross section is not limited, and can be any shape such as a hollow cross section, a round cross section, a polygonal cross section, a multi-leaf cross section, a flat cross section, but the fiber cross section is a hollow cross section, that is, a hollow fiber shape. If it exists, since the pressure loss in a membrane is reduced and high fluid permeability is obtained as a fluid separation membrane, it is preferable.
• the hollow part of the hollow fiber serves as a fluid flow path. Since the hollow fiber has a hollow portion, even when the fluid is permeated by either the external pressure type or the internal pressure type, the effect of significantly reducing the pressure loss is obtained when the fluid flows particularly in the fiber axis direction. The permeability is improved. In particular, in the case of the internal pressure type, the pressure loss is reduced, so that the fluid permeation rate is further improved.
• a form in which a dense layer is formed on the surface of the fiber and a portion other than the dense layer of the fiber is a support having the porous structure described above is preferable.
• the dense layer can be formed on one or both of the inner surface and the outer surface.
• the average diameter of the fluid separation membrane is small, the bendability and compressive strength are improved, so the average diameter is preferably 500 ⁇ m or less, more preferably 400 ⁇ m or less, and even more preferably 300 ⁇ m or less. Since the number of fibers that can be filled per unit volume increases as the average diameter of the fluid separation membrane decreases, the membrane area per unit volume can be increased and the permeate flow rate per unit volume can be increased.
• the lower limit of the average diameter of the fluid separation membrane is not particularly limited and can be arbitrarily determined, but is preferably 10 ⁇ m or more from the viewpoint of improving the handleability when producing the fluid separation membrane module.
• the average length of the fibers can be arbitrarily determined, and is preferably 10 mm or more from the viewpoint of improving the handleability when modularizing and improving the fluid permeation performance.
• the fluid separation membrane of the present invention has a total of 2 to 10,000 ppm of monocyclic or bicyclic aromatic compounds (hereinafter sometimes simply referred to as “aromatic compounds”) that are liquid or solid at 16 ° C. and atmospheric pressure. It is characterized by adsorbing and adsorbing 10 to 250,000 ppm of water.
• aromatic compounds monocyclic or bicyclic aromatic compounds
• the present inventors have found that the separation performance can be maintained for a long period of time by having the above-mentioned adsorption component in the fluid separation membrane.
• the adsorption amount of the above-described aromatic compound is a total value when plural kinds of aromatic compounds are adsorbed.
• the adsorption amount of the above-described aromatic compound is 1 ppm or less, it treats as what is not adsorb
• the adsorption amount of the aromatic compound may be 2 ppm or more, more preferably 10 ppm or more, and further preferably 100 ppm or more.
• the aromatic compound adsorption amount may be 10,000 ppm or less, more preferably 5,000 ppm or less, and even more preferably 1,000 ppm or less. .
• examples include sulfonic acid, nitrobenzene, aniline, thiophenol, benzonitrile, styrene, xylene, cresol, catechol, resorcinol, hydroquinone, phthalic acid, isophthalic acid, terephthalic acid, salicylic acid, and toluidine.
• the fluid separation membrane contains at least one selected from the group consisting of toluene, benzene and xylene because the effect of maintaining the separation performance is increased, and it is more preferable that the fluid separation membrane contains at least one of toluene or benzene. Most preferably, toluene is included.
• toluene is adsorbed at 2 ppm or more because the effect of maintaining the separation performance is particularly increased. Toluene is more preferably adsorbed at 50 ppm or more. Further, the amount of toluene adsorbed is preferably 2,000 ppm or less because plasticization of the fluid separation membrane is suppressed and high strength is obtained, and more preferably 800 ppm or less.
• the ratio of the adsorption amount (ppm) of toluene to the adsorption amount (ppm) of benzene is preferably 2 or more, because the effect of maintaining separation performance is increased, and is preferably 10 or more. And particularly preferred.
• the upper limit of the ratio of the adsorption amount (ppm) of toluene to the adsorption amount (ppm) of benzene is not particularly limited, but is preferably 200 or less, more preferably 100 or less, in order to exhibit the effect of coexistence of toluene and benzene.
• the amount of water adsorbed may be 10 ppm or more, but it is preferably 100 ppm or more because the effect of maintaining the separation performance is increased, and more preferably 1,000 ppm or more.
• the amount of water adsorbed may be 250,000 ppm or less, but is preferably 150,000 ppm or less because the strength of the fluid separation membrane is increased, and more preferably 50,000 ppm or less.
• the ratio of the amount of adsorbed water (ppm) to the amount of adsorbed aromatic compounds (ppm) is preferably 0.5 or more, because the effect of maintaining separation performance is increased, and particularly preferably 3 or more.
• the adsorption amount of the aromatic compound and water can be quantified as follows by the heat generation gas analysis method (TPD-MS method).
• a heating device with a temperature controller and a mass spectrometer are directly connected, and the fluid separation membrane is heated in a helium atmosphere.
• the temperature is first raised from room temperature to 80 ° C. at 10 ° C./min (step 1), held at 80 ° C. for 30 minutes (step 2), and further raised to 180 ° C. at 10 ° C./min (step 3). ) And hold at 180 ° C. for 30 minutes (step 4). Then, the amount of the aromatic compound and water vapor in the gas in steps 1 to 4 is measured.
• the measurement should be performed after wiping the surface of the fluid separation membrane with a waste cloth or the like. Assumed to be performed.
• the adsorption amount of the aromatic compound obtained from only the aromatic compound gas generated in steps 1 and 2 is Aa (ppm), and the adsorption of the aromatic compound obtained from only the amount of the aromatic compound gas generated in steps 3 and 4
• the amount is Ba (ppm)
• Ba / Aa is 0.1 or more because the separation performance can be maintained for a long period, more preferably 0.2 or more, and further preferably 0.3 or more.
• the water adsorption amount obtained from only the water vapor generated in steps 1 and 2 is Aw (ppm)
• the water adsorption amount obtained only from the water vapor amount generated in steps 3 and 4 is Bw (ppm).
• Bw / Aw is 0.1 or more because the separation performance can be maintained for a long period, more preferably 0.2 or more, and further preferably 0.3 or more.
• the curve plotting the amount of water generated against temperature changes has two or more peaks. This means that it is adsorbed, and the effect of maintaining the separation performance is increased, which is preferable.
• an embodiment in which the aromatic compound and water both have two or more peaks is particularly preferable.
• the measurement should be performed after wiping the surface of the fluid separation membrane with a waste cloth or the like. Assumed to be performed.
• the fluid separation membrane of the present invention is preferably used for gas separation, that is, a gas separation membrane.
• gas separation membrane is preferably used for separation applications in which acidic gas is extracted from a mixed gas containing acidic gas at a high concentration.
• the acid gas include carbon dioxide, hydrogen sulfide and the like.
• the fluid separation membrane of the present invention is a mixed gas containing carbon dioxide, particularly It is preferably used for natural gas separation.
• the fluid separation membrane of the present invention can be produced by a production method having a step of preparing a fluid separation membrane having a separation layer composed of a dense layer and a step of adsorbing an aromatic compound and water to the fluid separation membrane.
• Step of preparing a fluid separation membrane having a separation layer composed of a dense layer Although a commercially available fluid separation membrane before adsorbing an aromatic compound and water may be used, it is prepared by the following steps 1 to 3 as an example. be able to.
• This example is an example of a fluid separation membrane in which the dense layer and the support are made of carbon.
• a dense layer made of carbon is called a “dense carbon layer”, and a support made of carbon is called a “porous carbon support”.
• the manufacturing method of the fluid separation membrane in the present invention is not limited to the following.
• Step 1 is porous by carbonizing a molded body containing a resin that is a precursor of a porous carbon support (hereinafter sometimes referred to as “support precursor resin”) at 500 ° C. or more and 2,400 ° C. or less. This is a step of obtaining a carbon support.
• support precursor resin a resin that is a precursor of a porous carbon support
• thermoplastic resins include polyphenylene ether, polyvinyl alcohol, polyacrylonitrile, phenolic resin, aromatic polyester, polyamic acid, aromatic polyimide, aromatic polyamide, polyvinylidene fluoride, cellulose acetate, polyetherimide and their co-polymers Coalesce is mentioned.
• thermosetting resins include unsaturated polyester resins, alkyd resins, melamine resins, urea resins, polyimide resins, diallyl phthalate resins, lignin resins, urethane resins, phenol resins, polyfurfuryl alcohol resins and their co-polymers. Coalesce is mentioned. These may be used alone or in combination.
• thermoplastic resin capable of solution spinning is preferably used.
• polyacrylonitrile or aromatic polyimide from the viewpoint of cost and productivity.
• a disappearing component that can be lost after molding to the molded body containing the support precursor resin.
• a disappearing component that can be lost after molding to the molded body containing the support precursor resin.
• the structure can be formed and the average diameter of the pores forming the porous structure can be controlled.
• the support precursor resin and the disappearing resin are mixed to obtain a resin mixture.
• the mixing ratio is preferably 10 to 90% by weight of the disappearing resin with respect to 10 to 90% by weight of the support precursor resin.
• the disappearing resin is preferably selected from resins that are compatible with the carbonizable resin.
• the compatibility method may be mixing of resins only or adding a solvent.
• Such a combination of carbonizable resin and disappearing resin is not limited, and examples include polyacrylonitrile / polyvinyl alcohol, polyacrylonitrile / polyvinylphenol, polyacrylonitrile / polyvinylpyrrolidone, polyacrylonitrile / polylactic acid, and the like. It is preferable to phase-separate the obtained resin mixture in a compatible state in the process of molding. By doing in this way, a co-continuous phase separation structure can be revealed.
• the method for phase separation is not limited, and examples thereof include a thermally induced phase separation method and a non-solvent induced phase separation method.
• the particles include metal oxide, talc, silica, and the like, and examples of the metal oxide include magnesium oxide, aluminum oxide, zinc oxide, and the like.
• These particles are preferably mixed with the support precursor resin before molding and removed after molding.
• the removal method it can select suitably according to manufacturing conditions and the property of the particle
• the support precursor resin may be decomposed and removed simultaneously with carbonization, or may be washed before or after carbonization.
• the cleaning liquid can be appropriately selected according to the properties of the particles used from water, an alkaline aqueous solution, an acidic aqueous solution, an organic solvent and the like.
• a precursor of a porous carbon support can be formed by solution spinning.
• Solution spinning is a method in which a resin is dissolved in various solvents to prepare a spinning stock solution, which is passed through a bath made of a solvent that becomes a poor solvent for the resin to solidify the resin to obtain fibers. Examples of the solution spinning include dry spinning, dry wet spinning, and wet spinning.
• the surface of the porous carbon support can be opened by appropriately controlling the spinning conditions.
• the composition and temperature of the spinning dope and coagulation bath are appropriately controlled, or the spinning solution is discharged from the inner tube and the same solvent as the spinning solution from the outer tube. Or a solution in which the disappearing resin is dissolved is discharged at the same time.
• the fiber spun by such a method can be solidified in a coagulation bath, followed by washing with water and drying to obtain a precursor of a porous carbon support.
• the coagulating liquid include water, ethanol, saline, and a mixed solvent of these and the solvent used in Step 1.
• it can also be immersed in a coagulation bath or a water bath before a drying process, and a solvent and a loss
• the precursor of the porous carbon support can be subjected to infusibilization before carbonization.
• the method of infusibilization treatment is not limited, and a known method can be adopted.
• the porous carbon support precursor that has been infusibilized as necessary is finally carbonized to become a porous carbon support.
• Carbonization is preferably performed by heating in an inert gas atmosphere.
• the inert gas include helium, nitrogen, and argon.
• the flow rate of the inert gas may be an amount that can sufficiently reduce the oxygen concentration in the heating device, and it is preferable to select an optimal value appropriately depending on the size of the heating device, the amount of raw material supplied, the carbonization temperature, and the like.
• the disappearing resin may be removed by thermal decomposition with heat during carbonization.
• the carbonization temperature is preferably 500 ° C. or more and 2,400 ° C. or less.
• the carbonization temperature is the highest temperature reached when carbonization is performed.
• the carbonization temperature is more preferably 900 ° C. or higher.
• the carbonization temperature is more preferably 1,500 ° C. or lower.
• the porous carbon support Before the carbonizable resin layer is formed on the porous carbon support in Step 2 described below, the porous carbon support may be subjected to a surface treatment in order to improve the adhesion with the carbonizable resin layer.
• a surface treatment include oxidation treatment and chemical coating treatment.
• the oxidation treatment include chemical oxidation using nitric acid and sulfuric acid, electrolytic oxidation, and gas phase oxidation.
• medical solution coating process provision of the primer and sizing agent to a porous carbon support body is mentioned.
• Step 2 is a step of forming a carbonizable resin layer serving as a precursor of the dense carbon layer on the porous carbon support prepared in Step 1.
• the thickness of the dense carbon layer can be arbitrarily set. Therefore, the separation membrane structure can be easily designed, for example, the fluid permeation rate can be improved by reducing the thickness of the dense carbon layer.
• the carbonizable resin various resins that exhibit fluid separability after carbonization can be used. Specifically, polyacrylonitrile, aromatic polyimide, polybenzoxazole, aromatic polyamide, polyphenylene ether, phenol resin, cellulose acetate, polyfurfuryl alcohol, polyvinylidene fluoride, lignin, wood tar, intrinsic porous polymer (PIM), etc. Is mentioned. If the resin layer is polyacrylonitrile, aromatic polyimide, polybenzoxazole, aromatic polyamide, polyphenylene ether, or intrinsic porous polymer (PIM), it is preferable because of its excellent fluid permeation rate and separability. Polyacrylonitrile or aromatic polyimide is preferable. More preferred.
• the carbonizable resin may be the same as or different from the above-described support precursor resin.
• the formation method of the carbonizable resin layer is not limited, and a known method can be adopted.
• a general forming method is a method in which a carbonizable resin itself is coated on a porous carbon support. After coating the precursor of the resin on the porous carbon support, the precursor is reacted.
• a method of forming a carbonizable resin layer or a counter diffusion method in which a reactive gas or solution is allowed to flow from the outside and inside of the porous carbon support to react can be employed. Examples of the reaction include heating, polymerization by a catalyst, cyclization, and crosslinking reaction.
• Examples of the coating method for the carbonizable resin layer include a dip coating method, a nozzle coating method, a spray method, a vapor deposition method, and a cast coating method.
• the dip coating method or the nozzle coating method is preferable when the porous carbon support is fibrous, and the dip coating method or the cast coating method is preferable when the porous carbon support is a film.
• the dip coating method is a method in which a porous carbon support is dipped in a coating stock solution containing a solution of carbonizable resin or a precursor thereof and then drawn out.
• the viscosity of the coating solution in the dip coating method is arbitrarily set depending on conditions such as the surface roughness of the porous carbon support, the pulling speed, and the desired film thickness.
• the shear viscosity at a shear rate of 0.1 s ⁇ 1 is preferably 10 mPa ⁇ s or more, and more preferably 50 mPa ⁇ s or more.
• the viscosity of the coating stock solution is preferably 1,000 mPa ⁇ s or less, and more preferably 800 mPa ⁇ s or less.
• the pulling speed of the porous carbon support in the dip coating method is also arbitrarily set according to the coating conditions.
• the pulling speed is high, the carbonizable resin layer becomes thick and defects can be suppressed. Therefore, the pulling rate is preferably 1 mm / min or more, and more preferably 10 mm / min or more.
• the pulling speed is preferably 1,000 mm / min or less, more preferably 800 mm / min or less.
• the temperature of the coating stock solution is preferably 20 ° C or higher and 80 ° C or lower. When the temperature of the coating stock solution is high, the surface tension is lowered, the wettability to the porous carbon support is improved, and the thickness of the carbonizable resin layer becomes uniform.
• a resin or resin precursor is laminated on a porous carbon support by passing the porous carbon support through a nozzle filled with a coating stock solution that is a solution of carbonizable resin or its precursor. It is a method to do.
• the viscosity and temperature of the coating stock solution, the nozzle diameter, and the passing speed of the porous carbon support can be arbitrarily set.
• porous carbon support / carbonizable resin layer composite The porous carbon support with carbonized resin layer formed in step 2 (hereinafter referred to as “porous carbon support / carbonizable resin layer composite”) is treated before carbonization (step 3).
• a fusing process may be performed.
• the method for the infusibilization treatment is not limited, and it conforms to the infusibilization treatment for the precursor of the porous carbon support described above.
• Step 3 Step of forming a dense carbon layer
• the porous carbon support / carbonizable resin layer composite prepared in step 2 and further subjected to infusibilization treatment as necessary is heated to carbonize the carbonizable resin layer to form a dense carbon layer. It is a process of forming.
• the porous carbon support / carbonizable resin layer composite in an inert gas atmosphere.
• the inert gas include helium, nitrogen, and argon.
• the flow rate of the inert gas may be an amount that can sufficiently reduce the oxygen concentration in the heating device, and it is preferable to select an optimal value appropriately depending on the size of the heating device, the amount of raw material supplied, the carbonization temperature, and the like.
• the upper limit of the flow rate of the inert gas is not limited, it is preferable that the upper limit of the flow rate of the inert gas is appropriately set according to the temperature distribution and the design of the heating device from the viewpoint of reducing the temperature change in the heating device.
• the surface of the porous carbon support is chemically etched and the size of the pore diameter on the surface of the porous carbon support is controlled.
• the active gas include oxygen, carbon dioxide, water vapor, air, and combustion gas.
• the concentration of the active gas in the inert gas is preferably from 0.1 ppm to 100 ppm.
• the carbonization temperature in this step can be arbitrarily set as long as the permeation rate and separation factor of the fluid separation membrane are improved, but it should be lower than the carbonization temperature when carbonizing the precursor of the porous carbon support in step 1. preferable. Thereby, the permeation
• the carbonization temperature in this step is preferably 500 ° C. or higher, and more preferably 550 ° C. or higher. Moreover, 850 degrees C or less is preferable and 800 degrees C or less is more preferable.
• Step of adsorbing aromatic compound and water the aromatic compound and water are adsorbed on the fluid separation membrane thus prepared. This process may be performed in a continuous process or a batch process.
• the method for adsorbing the aromatic compound is not particularly limited, and from the viewpoint of the amount of adsorption and production efficiency, it is possible to appropriately select immersion in a liquid aromatic compound, exposure to a gaseous aromatic compound, and the like. In that case, it is preferable from the viewpoint of improving the adsorption efficiency to appropriately heat and stir.
• the method for adsorbing water is not particularly limited, and can be appropriately selected from the viewpoint of the amount of adsorption, production efficiency, and the like, such as immersion in water and exposure to water vapor.
• the adsorption conditions can be selected so as to obtain a desired adsorption amount such as heating and stirring as appropriate.
• an aromatic compound it is preferable to mix an aromatic compound and water and adsorb them at the same time from the viewpoint of efficiency or from the viewpoint of safety and equipment maintenance.
• the aromatic compound is solid, it is preferable to carry out the adsorption treatment described above after dissolving it in water or a solvent that can be dissolved in advance.
• step 2 the total amount of the generated amount when held at 180 ° C. for 30 minutes (step 2) was defined as the amount of adsorption of toluene, benzene and water.
• the adsorption amount of the aromatic compound obtained from only the aromatic compound gas generated in steps 1 and 2 is Aa (ppm), and the aromatic compound obtained from only the amount of the aromatic compound gas generated in steps 3 and 4 Similarly, the adsorption amount of water is Ba (ppm), and similarly, the adsorption amount of water obtained from only the water vapor generated in steps 1 and 2 is Aw (ppm), and is obtained only from the amount of water vapor generated in steps 3 and 4.
• Ba / Aa and Bw / Aw were calculated with the amount of water adsorbed as Bw (ppm).
• the fluid separation membrane of the present invention was measured on-line by measuring the generation amount of toluene, benzene, and water while increasing the temperature from room temperature to 300 ° C. at 10 ° C./min by the heat generation gas analysis method (TPD-MS method). The number of peaks in the curve plotting the amount of generation against temperature change was confirmed.
• TPD-MS method heat generation gas analysis method
• Carbon dioxide and methane are used as measurement gases, and the pressure change on the permeate side of carbon dioxide and methane per unit time is measured with an external pressure method at a measurement temperature of 25 ° C in accordance with the pressure sensor method of JIS K7126-1 (2006). did.
• the pressure difference between the supply side and the transmission side was set to 0.11 MPa (82.5 cmHg).
• the permeation rate Q of the permeated gas was calculated by the following formula, and the separation factor ⁇ was calculated as the ratio of the permeation rate of carbon dioxide / methane.
• STP means standard conditions.
• the membrane area was calculated from the outer diameter of the fluid separation membrane and the length existing in the region contributing to gas separation.
• Permeation speed Q [gas permeation flow rate (cm 3 ⁇ STP)] / [membrane area (cm 2 ) ⁇ time (s) ⁇ pressure difference (cmHg)]
• the gas separation factor was measured immediately after starting and after 100 hours. Furthermore, the separation factor retention after 100 hours of use was determined by dividing the latter by the former.
• Example 1 70 g of polyacrylonitrile (MW 150,000) manufactured by Polyscience, 70 g of polyvinyl pyrrolidone (MW 40,000) manufactured by Sigma-Aldrich, and 400 g of dimethyl sulfoxide (DMSO) manufactured by Wakken as a solvent were put into a separable flask. A solution was prepared at 135 ° C. with stirring and reflux for 2.5 hours.
• DMSO dimethyl sulfoxide
• the solution was discharged from the inner tube of the core-sheath type double cap at 3.5 mL / min, and the DMSO 90 wt% aqueous solution was 5.3 mL / min from the outer tube.
• a coagulation bath made of pure water at 25 ° C., then taken up at a speed of 5 m / min, and wound on a roller to obtain a raw yarn.
• the air gap was 9 mm
• the immersion length in the coagulation bath was 15 cm.
• the obtained raw yarn was translucent and caused phase separation.
• the obtained raw yarn was washed with water and then dried at 25 ° C. for 24 hours in a circulation dryer to produce a raw yarn.
• the dried raw yarn was passed through an electric furnace at 255 ° C., and infusible treatment was performed by heating in an oxygen atmosphere for 1 hour.
• the infusible raw yarn was carbonized under the conditions of a nitrogen flow rate of 1 L / min, a temperature increase rate of 10 ° C./min, an ultimate temperature of 1000 ° C., and a holding time of 1 min to produce a porous carbon support.
• a nitrogen flow rate of 1 L / min a temperature increase rate of 10 ° C./min
• an ultimate temperature of 1000 ° C. a holding time of 1 min to produce a porous carbon support.
• carbonization was performed under the conditions of a nitrogen flow rate of 1 L / min, a heating rate of 10 ° C./min, an ultimate temperature of 600 ° C., and a holding time of 1 min, to obtain a hollow fiber fluid separation membrane.
• a dense carbon layer was present on the outer surface, and the interior had a co-continuous structure composed of carbon.
• Example 2 A fluid separation membrane was obtained in the same manner as in Example 1. Furthermore, 250 mL of toluene manufactured by Kanto Chemical Co., Ltd. and 250 mL of pure water were mixed, heated to 50 ° C., and exposed to the vapor for 24 hours.
• Example 3 A fluid separation membrane was obtained in the same manner as in Example 1. Furthermore, 250 mL of benzene manufactured by Kanto Chemical Co., Ltd. and 250 mL of pure water were mixed, heated to 50 ° C., and exposed to the vapor for 24 hours.
• Example 4 A fluid separation membrane was obtained in the same manner as in Example 1. Furthermore, 250 mL of toluene manufactured by Kanto Chemical Co., Ltd. and 250 mL of pure water were mixed, heated to 50 ° C., and exposed to the vapor for 4 hours.
• Example 1 A fluid separation membrane was obtained in the same manner as in Example 1. Thereafter, the adsorption treatment was not performed, and the amount of adsorption of toluene, benzene and water, the peak number of the heat generation amount curve, and the measurement of the gas separation coefficient were carried out.
• Example 2 A fluid separation membrane was obtained in the same manner as in Example 1. In addition, 600 mL of water was heated to 50 ° C. and exposed to the vapor for 24 hours.
• Table 1 shows the evaluation results of the fluid separation membranes prepared in each example and comparative example.

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