Carbon dioxide separation membrane manufacturing method and separation membrane module manufacturing method

Abstract

Provided are: a carbon dioxide separation membrane manufacturing method that is capable of manufacturing an asymmetrically porous carbon dioxide separation membrane with low carbon dioxide emission volume; and a separation membrane module manufacturing method.　This carbon dioxide separation membrane manufacturing method is for manufacturing an asymmetrically porous carbon dioxide separation membrane, the method including: a casting step in which, using evaporation-induced phase separation, a dope that is a composition obtained by dissolving a resin in a mixed solvent that contains a good solvent with a boiling point 100°C or below and a poor solvent with a boiling point 120°C or below is cast onto a support body to form a web; a drying step in which, after the casting step, the web is dried; and a rolling-up step in which, after the drying step, a carbon dioxide separation membrane that is the dried form of the web is rolled up.

Description

Method for producing carbon dioxide separation membrane and method for producing separation membrane module

[0001] The present invention relates to a method for producing a carbon dioxide separation membrane and a method for producing a separation membrane module.

[0002] Carbon dioxide (CO ２ The development of technology to efficiently separate and capture carbon dioxide (CO₂) is an important industrial and environmental issue. One known technology for separating and capturing CO₂ is membrane separation using resins. In CO₂ separation using resin separation membranes, CO₂ is first adsorbed onto the surface of the resin. It is believed that the adsorbed CO₂ dissolves inside the resin and then passes through the gaps in the molecular chains of the resin. Because the ease of adsorption and dissolution on the resin surface differs depending on the gas type, there is a difference in permeability between CO₂ and other gases, allowing them to be separated.

[0003] It is generally known that there is a trade-off between the separation ability and permeability of carbon dioxide in a separation membrane. A pressure difference is required to allow carbon dioxide to permeate, which requires energy for pressurization. High permeability reduces the energy required for pressurization to allow carbon dioxide to permeate. Therefore, from the perspective of reducing the total cost of carbon dioxide separation and capture, permeability is more important than separation ability in order to reduce the energy required for pressurization.

[0004] The thinner the separation membrane, the higher the permeability. However, if the separation membrane is too thin, it becomes difficult to handle. For this reason, a method has been devised in which a thin gas separation functional layer is formed on a porous support layer. By forming the separation membrane as a laminate of a porous support layer and a thin gas separation functional layer, it is possible to improve permeability while maintaining mechanical strength.

[0005] One method for forming a laminate of a porous support layer and a thin gas separation functional layer is to form an asymmetric porous membrane by phase separation from a resin solution. This asymmetric porous membrane has a dense layer (also called a skin layer) that contributes to separation and a porous layer that functions as a support layer and provides mechanical strength.

[0006] The Robb-Srirajan method is a well-known method for forming an asymmetric porous membrane (see, for example, Patent Documents 1 to 3). In the Robb-Srirajan method, for example, a resin is dissolved in a good solvent, which is then applied to a glass plate, which is then immersed in water, a poor solvent. When the membrane is dried after immersion, the resin is unlikely to remain in the areas immersed in the poor solvent, forming voids, and an asymmetric porous membrane is formed.

[0007] JP 2022-73291 A JP 2020-73249 A International Publication No. 2016 / 136294

[0008] However, the Lobb-Srirajan method requires immersion in a poor solvent, which requires a large amount of thermal energy for drying. Currently, generating thermal energy in factories and other facilities is more efficient by burning fossil fuels than by using electricity derived from renewable energy sources. Therefore, thermal energy is primarily generated by burning fossil fuels, which generates carbon dioxide. In other words, producing asymmetric porous membranes using the Lobb-Srirajan method involves emitting a large amount of carbon dioxide. In the technology described in Patent Document 3, the poor solvent contained in the membrane after immersion in a poor solvent is replaced with an alcohol or hydrocarbon with a lower boiling point in order to lower the drying temperature. However, this method makes the process complicated. Furthermore, this method also does not sufficiently reduce the thermal energy required for drying, resulting in the emission of a large amount of carbon dioxide.

[0009] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for producing a carbon dioxide separation membrane and a method for producing a separation membrane module, which can produce an asymmetric porous carbon dioxide separation membrane with a small amount of carbon dioxide emission.

[0010] The above-mentioned problems of the present invention can be solved by the following means.

[0011] 1. A method for producing an asymmetric porous carbon dioxide separation membrane, using evaporation-induced phase separation, comprising: a casting step of casting a dope, which is a composition obtained by dissolving a resin in a mixed solvent containing a good solvent having a boiling point of 100°C or less and a poor solvent having a boiling point of 120°C or less, onto a support to form a web; a drying step of drying the web after the casting step; and a winding step of winding up the dried web, which is a carbon dioxide separation membrane, after the drying step.

[0012] 2. The method for producing a carbon dioxide separation membrane according to claim 1, wherein the temperatures of the upper and lower surfaces of the dope are made different in the casting step.

[0013] 3. The method for producing a carbon dioxide separation membrane according to claim 1, wherein the drying step includes a plurality of drying steps each performed at a different drying temperature.

[0014] 4. The method for producing a carbon dioxide separation membrane according to Item 1, wherein the time for drying the dope or the web at a temperature of 50° C. or higher is 100 minutes or less in total from the casting step to the winding step.

[0015] 5. The method for producing a carbon dioxide separation membrane according to Item 1, wherein the mixed solvent contains a polar solvent as the poor solvent.

[0016] 6. The method for producing a carbon dioxide separation membrane according to Item 1, wherein the ratio of the poor solvent in the mixed solvent is within a range of 5 to 29 mass%.

[0017] 7. The method for producing a carbon dioxide separation membrane according to Item 1, wherein the resin is a cellulose ester resin having a structure represented by the following general formula (1):

[0018] [In general formula (1), R １ , R ２ and R ３ are each independently a hydrogen atom, an acetyl group, a propionyl group, or a butyryl group, and n represents the degree of polymerization.

[0019] 8. The method for producing a carbon dioxide separation membrane according to Item 1, further comprising a stretching step of stretching the web after the casting step.

[0020] 9. A method for producing a separation membrane module, comprising the step of producing a carbon dioxide separation membrane by the method for producing a carbon dioxide separation membrane according to any one of items 1 to 8.

[0021] According to the present invention, an asymmetric porous carbon dioxide separation membrane can be produced with a small amount of carbon dioxide discharged.

[0022] Schematic diagram showing an example of a manufacturing apparatus used in a method for manufacturing a carbon dioxide separation membrane. SEM image of a cross section of a carbon dioxide separation membrane. Schematic diagram showing an example of a separation membrane module, a partially cutaway perspective view showing a part of a cylindrical wound body in which a laminate is wound around a permeation gas collecting pipe. Schematic diagram showing the state before the laminate is wound around the permeation gas collecting pipe.

[0023] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following detailed description and drawings are provided for illustrative purposes only and do not limit the scope of the present invention.

[0024] One or more embodiments of the present invention will now be described with reference to the drawings, although the scope of the present invention is not limited to the disclosed embodiments.

[0025] In this application, the symbol "to" is used to mean that the numerical values ​​before and after it are included as the lower limit and upper limit.

[0026] [Carbon dioxide separation membrane manufacturing apparatus and manufacturing process]

[0027] The method for producing a carbon dioxide separation membrane of the present invention uses evaporation-induced phase separation (EIPS). Evaporation-induced phase separation uses a dope, which is a composition in which a resin is dissolved in a mixed solvent containing a good solvent and a poor solvent. Evaporation-induced phase separation is a method for producing a porous membrane by evaporating the good solvent and poor solvent from the dope. Unlike non-solvent-induced phase separation (NIPS) methods such as the Loeb-Srirajan method, evaporation-induced phase separation does not include a step of immersing the membrane in a poor solvent. Therefore, by using evaporation-induced phase separation, the present invention can reduce the thermal energy required for drying, thereby reducing carbon dioxide emissions.

[0028] 1 is a schematic diagram showing an example of a production apparatus 1 used in the method for producing a carbon dioxide separation membrane 4 according to the present invention. The production apparatus 1 shown in FIG. 1 includes a casting apparatus 101, a first drying apparatus 102, a stretching apparatus 103, a second drying apparatus 104, and a winding apparatus 105.

[0029] The casting apparatus 101 performs a casting process and includes a support 101a which is an endless belt, a casting die 101b, a heating device 101c, and a peeling roll 101g.

[0030] Support 101a is held rotatably (in the direction of the arrow in the figure) by rolls 101a1 and 101a2. Support 101a preferably has a mirror-finished surface, such as a cast metal belt with a plated surface. The width of support 101a is preferably 1700 to 2700 mm.

[0031] The casting die 101b casts the dope 2 onto the support 101a. The cast dope 2 is cast while being transported together with the support 101a. The width of the cast dope 2 is preferably 80 to 99% of the width of the support 101a. The thickness of the cast dope 2 can be adjusted by the amount of the dope 2, the transport speed, etc. so that the carbon dioxide separation membrane 4 to be produced has a predetermined thickness.

[0032] The heating device 101c removes the solvent from the dope 2 on the support 101a to form a web 3 that can be peeled off from the support 101a. The heating device 101c includes a drying box 101c1, a first heated air supplying device 101d disposed in the drying box 101c1, a second heated air supplying device 101e, and an exhaust pipe 101f. The first heated air supplying device 101d includes a heated air supplying pipe 101d1 and a header 101d2. The second heated air supplying device 101e includes a heated air supplying pipe 101e1 and a header 101e2.

[0033] The temperature of the heated air supplied by the first heated air supply device 101d may be constant or may vary in several stages depending on the direction of movement of the support 101a. The same applies to the temperature of the heated air supplied by the second heated air supply device 101e.

[0034] The pressure of the heated air supplied from the first heated air supply device 101d and the second heated air supply device 101e is preferably 50 to 5000 Pa, taking into consideration the uniformity of solvent evaporation, the degree of dispersion of the fine particles, and the like.

[0035] The temperature of the dope 2 in the casting process is preferably −5 to 70°C, more preferably 0 to 45°C, taking into consideration the transport speed associated with the evaporation time of the solvent, the degree of dispersion of the fine particles, productivity, and the like. In the present invention, it is preferable to make the temperatures of the upper and lower surfaces of the dope 2 different during the casting process. This facilitates the change in the ratio of the poor solvent to the good solvent in the thickness direction of the dope 2, facilitating the formation of an asymmetric porous membrane. The upper surface of the dope 2 is the surface opposite the support 101a. The temperature of the upper surface of the dope 2 can be adjusted, for example, by the heating temperature of the first heated air supplying device 101d and the second heated air supplying device 101e. The lower surface of the dope 2 is the surface facing the support 101a. The temperature of the lower surface of the dope 2 can be adjusted, for example, by the temperature of the support 101a.

[0036] 1 shows a case where hot air is used in the heating device 101c, but the heating means is not particularly limited and can be appropriately selected as needed. For example, the heating means may be a method of heating the dope 2 on the support 101a with an infrared heater or a method of blowing hot air onto the back side of the support 101a to heat it from the back side.

[0037] The peeling roll 101g peels the web 3 formed by removing a certain amount of the solvent from the dope 2 from the support 101a.

[0038] The casting time can be adjusted depending on the thickness of the carbon dioxide separation membrane 4 to be produced, the solvent used, etc. Taking into consideration the peelability from the support 101a, the casting time is preferably 0.5 to 5 minutes.

[0039] The amount of solvent remaining in the web 3 when the web 3 is peeled from the support 101a is preferably 30 to 200% by mass, taking into consideration peelability, transportability after peeling, physical properties of the carbon dioxide separation membrane 4, and the like.

[0040] When the web 3 is peeled from the support 101a, the peeling tension and the subsequent conveying tension stretch the web 3 in the conveying direction (machine direction: MD) of the web 3. Therefore, in this embodiment, the peeling and conveying tension when peeling the web from the support 101a is preferably 50 to 400 N / m.

[0041] The amount of solvent remaining in the web 3 from the time it is peeled from the support 101a until stretching in the stretching device 103 is started is preferably 5 to 50% by mass, taking into consideration curling, wrinkles, etc. of the carbon dioxide separation membrane 4.

[0042] The first drying device 102 performs a first drying step. The first drying device 102 includes a drying box 102a, one or more upper transport rolls 102d, and one or more lower transport rolls 102e. The drying box 102a has a dry air intake 102b and an exhaust 102c. The upper transport rolls 102d and the lower transport rolls 102e transport the web 3. The first drying device 102 can adjust the amount of solvent contained in the web 3 before it enters the stretching device 103.

[0043] The suitable drying temperature in the first drying device 102 varies depending on the amount of residual solvent in the web 3 when it enters the stretching device 103. The drying temperature may be appropriately determined taking into consideration the amount of residual solvent, drying time, shrinkage unevenness, stability of the amount of expansion and contraction, etc., and is preferably 50 to 200°C. A drying temperature of 50°C or higher makes it easy to sufficiently remove the solvent. A drying temperature of 200°C or lower reduces the energy required for drying and reduces carbon dioxide emissions. The drying temperature may be constant or may be divided into several stages, for example, 2 to 4 stages.

[0044] The expansion rate of the web 3 in the MD direction from the time of peeling from the support 101a until the start of stretching in the stretching device 103 is preferably 1 to 25%, taking into consideration the elastic modulus, optical properties, etc. of the carbon dioxide separation membrane 4. Furthermore, the expansion rate of the web 3 in the direction perpendicular to the conveyance direction (transverse direction: TD) is preferably −1 to −25%, taking into consideration the elastic modulus, optical properties, etc. of the carbon dioxide separation membrane 4.

[0045] The stretching device 103 performs the stretching step. The method for producing a carbon dioxide separation membrane of the present invention includes a stretching step of stretching the web after the casting step, thereby making it possible to adjust the pore size of the porous layer of the carbon dioxide separation membrane 4. Note that the method for producing a carbon dioxide separation membrane of the present invention does not necessarily have to include the stretching step.

[0046] The stretching device 103 includes an outer box 103a and a tenter 103d placed inside the outer box 103a. The outer box 103a has a dry air intake port 103b and an exhaust port 103c. The tenter 103d may be, for example, a clip tenter or a pin tenter. The tenter may be selected as needed.

[0047] In the tenter 103d, the web 3 can be stretched in the MD direction and the TD direction as necessary. The stretching ratio in the stretching step is preferably 10 to 50% in order to control the permeability so that porous particles are connected to each other. The stretching ratio in the stretching step is a value calculated using the following formula. The width from the center to the edge of the web 3 is a value measured using a C-type JIS Class 1 steel scale. Stretching ratio (%) = (width from the center to the edge of the web 3 after stretching / width from the center to the edge of the web 3 before stretching) x 100

[0048] The amount of residual solvent in the web at the start of stretching in the stretching device 103 is preferably 10 to 30% by mass, taking into consideration scratches, shrinkage, deformation, etc. The positions of the dry air intake 103b and the discharge port 103c may be reversed. Although the case where heated air is used as the solvent removal means in the stretching device 103 is shown, the solvent removal means is not particularly limited. The solvent removal means in the stretching device 103 may be a means using heated air or a means using, for example, an infrared heater.

[0049] The second drying device 104 performs a second drying step. The method for producing a carbon dioxide separation membrane of the present invention includes the second drying step, which makes it easier to form an asymmetric porous membrane. Note that the method for producing a carbon dioxide separation membrane of the present invention does not necessarily have to include the second drying step.

[0050] The second drying device 104 includes a drying box 104a, one or more upper transport rolls 104d, and one or more lower transport rolls 104e. The drying box 104a has a dry air intake 104b and an exhaust 104c. The upper transport roll 104d and the lower transport roll 104e transport the web 3. The number of transport rolls arranged in the second drying device 104 can be appropriately determined depending on the drying conditions, method, length of the carbon dioxide separation membrane 4 to be manufactured, etc. The upper transport roll 104d and the lower transport roll 104e are free-rotating rolls that are not driven to rotate by a drive source. Furthermore, not all of the transport rolls between the second drying device 104 and the winding device 105 are free-rotating rolls; typically, one to several transport drive rolls (rolls that are driven to rotate by a drive source) are required. Essentially, the purpose of the transport drive rolls is to transport the carbon dioxide separation membrane 4 by their own drive. For this reason, the transport drive roll is provided with a mechanism for synchronizing the transport of the carbon dioxide separation membrane 4 with the rotation of the drive roll by using a nip, suction (air suction), or the like.

[0051] In the second drying step in the second drying device 104, heated air, infrared rays, or the like may be used alone, or heated air and infrared rays may be used in combination. For simplicity, it is preferable for the second drying device 104 to use heated air. Note that FIG. 1 shows a case in which the second drying device 104 uses heated air. The drying temperature in the second drying step may be determined appropriately taking into consideration the amount of residual solvent, drying time, uneven shrinkage, stability of the amount of expansion and contraction, etc., and is preferably 50 to 200°C. A drying temperature of 50°C or higher makes it easy to sufficiently remove the solvent. A drying temperature of 200°C or lower reduces the energy required for drying and reduces carbon dioxide emissions. The drying temperature may be constant or may be divided into several stages, for example, 2 to 4 stages.

[0052] The drying temperature in the second drying step is preferably different from the drying temperature in the first drying step, and is preferably higher than the drying temperature in the first drying step, which makes it easier to form an asymmetric porous membrane.

[0053] The residual solvent amount in the carbon dioxide separation membrane 4 after the drying treatment in the second drying device 104 is preferably 0.01 to 15% by mass, taking into consideration the load of the second drying step, dimensional stability, expansion / contraction rate during storage, etc. In this embodiment, the web 3 formed in the casting device 101 has the solvent gradually removed in the second drying device 104, and the web 3 with a residual solvent amount of 15% by mass or less is referred to as the carbon dioxide separation membrane 4.

[0054] The winding device 105 performs the winding process. The winding device 105 winds the carbon dioxide separation membrane 4, which is the dried body of the web 3, onto a winding core to the required length. When winding, it is preferable to cool the carbon dioxide separation membrane 4 to room temperature to prevent scratches, loosening of the winding, etc. due to shrinkage after winding. There are no particular restrictions on the winding machine used, and a commonly used one may be used. The winding method may be a constant tension method, a constant torque method, a taper tension method, a program tension control method with constant internal stress, or the like.

[0055] The stretch rate of the wound carbon dioxide separation membrane 4 is preferably 0 to 20% in the MD direction and -3 to 20% in the TD direction, taking into consideration the physical properties of the carbon dioxide separation membrane 4 and the like.

[0056] In the method for producing the carbon dioxide separation membrane 4 of the present invention, the time for drying the dope 2 or the web 3 at a temperature of 50° C. or higher is preferably 100 minutes or less in total from the casting step to the winding step, which can reduce the energy required for drying and the amount of carbon dioxide emitted.

[0057] [Dope] The dope according to the present invention is a composition in which a resin is dissolved in a mixed solvent containing a good solvent having a boiling point of 100° C. or less and a poor solvent having a boiling point of 120° C. or less, thereby reducing the heat energy required for drying and, in turn, reducing the amount of carbon dioxide emissions.

[0058] A good solvent is a solvent that has a strong interaction with the resin used and can dissolve the resin alone. For example, if the resin is a cellulose resin, a good solvent can dissolve the hydrogen bond entanglements within the cellulose resin molecular chains. Resin molecules swell and elongate in a good solvent, dissolving them. When a resin is mixed with a solvent, if the cohesive force between the resin molecules is weaker than the affinity between the resin molecules and the solvent, the resin molecules dissolve through a swelling process. Specifically, a solvent is considered to be a good solvent if, after a dissolution test in which the resin used is mixed with a solvent to a concentration of 1% by mass and stirred for 24 hours, no solids remaining in the resin can be visually confirmed. When two or more resins are used, the ratio of each resin mixed with the solvent in the dissolution test is adjusted to within a total of 1% by mass, the same as the ratio of each resin in the dope used to manufacture the carbon dioxide separation membrane 4.

[0059] A poor solvent is a solvent that has a weak interaction with the resin used, and when mixed with the resin, the resins come together and repel the solvent (partial precipitation). Specifically, a solvent is considered to be a poor solvent if it is mixed so that the resin is 1% by mass, stirred for 24 hours, and the presence of undissolved solids can be visually confirmed. When two or more resins are used, the ratio of the resins is adjusted within 1% by mass so that it is the same as the ratio of the resins used.

[0060] From the viewpoint of reducing the environmental load, the poor solvent is preferably a polar solvent, and more preferably water.

[0061] The good solvent and poor solvent differ depending on the resin used. For example, when the resin is a cellulose ester resin, the good solvent and poor solvent differ depending on the acyl group substitution degree of the cellulose ester resin. For example, when the resin is diacetyl cellulose (acetyl group substitution degree 2.4) or cellulose acetate propionate, acetone is a good solvent. For example, when the resin is triacetyl cellulose (acetyl group substitution degree 2.8), acetone is a poor solvent.

[0062] Diacetyl cellulose has a low degree of acetyl group substitution and strong hydrogen bonds within the molecular chain. Therefore, when diacetyl cellulose is mixed with dichloromethane at a concentration of 1% by mass and stirred for 24 hours, it does not dissolve. Therefore, when the resin is diacetyl cellulose, dichloromethane is a poor solvent. Here, if about 10% of a water-soluble alcohol solvent is mixed with dichloromethane to prevent hydrogen bonding between the hydroxy groups of diacetyl cellulose, diacetyl cellulose becomes soluble in the mixed solvent. Although triacetyl cellulose and cellulose acetate propionate can be dissolved in dichloromethane alone, a small amount of a water-soluble alcohol solvent may be mixed with dichloromethane to prevent molecular chain curling and reduce viscosity when using triacetyl cellulose or cellulose acetate propionate, in order to achieve the same effect as above.

[0063] Examples of solvents that may be contained in the mixed solvent according to the present invention include methyl formate, ethyl formate, methyl acetate, ethyl acetate, amyl acetate, propyl acetate, methyl ethyl ketone (2-butanone), methyl isobutyl ketone, acetone, N-methylpyrrolidone, dimethylformamide, dioxane, dioxolane, dioxolane derivatives, organic halogen compounds such as dichloromethane, chloroform, tetrachloroethane, dimethyl sulfoxide, and methylene chloride, tetrahydrofuran, cyclohexanone, 2,2,2-trimethylsilylpropane, and the like. Examples of the alcohol having 1 to 8 carbon atoms include fluoroethanol, 2,2,3,3-hexafluoro-1-propanol, 1,3-difluoro-2-propanol, 1,1,1,3,3,3-hexafluoro-2-methyl-2-propanol, 1,1,1,3,3,3-hexafluoro-2-propanol, 2,2,3,3,3-pentafluoro-1-propanol, nitroethane, alcohols having 1 to 8 carbon atoms, monochlorobenzene, benzene, cyclohexane, methyl cellosolve, ethylene glycol monomethyl ether, water, etc. Examples of the alcohol having 1 to 8 carbon atoms include methanol, ethanol, n-propanol (1-propanol), iso-propanol (2-propanol), n-butanol (1-butanol), sec-butanol (2-butanol), tert-butanol (2-methyl-2-propanol), etc.

[0064] The mixed solvent according to the present invention may contain a good solvent having a boiling point of more than 100°C and / or a poor solvent having a boiling point of more than 120°C, but it is preferable that it does not contain any of these.

[0065] The ratio of the poor solvent in the mixed solvent is preferably in the range of 5 to 29% by mass, more preferably in the range of 18 to 29% by mass, which allows the viscosity during solution casting to be controlled to an appropriate value and maintains productivity.

[0066] Examples of the resin include cellulose ester resin, cycloolefin resin, polyester resin, polyimide resin, polyamide resin, polystyrene resin, acrylic resin, polysulfone resin, polyethylene resin, polypropylene resin, cellophane, vinyl resin, polycarbonate resin, polyarylate resin, polyether ketone resin, polyether ketone imide resin, and fluororesin.

[0067] Examples of cellulose ester resins include diacetyl cellulose, triacetyl cellulose, cellulose acetate propionate, cellulose acetate butyrate, and cellulose acetate propionate butyrate.

[0068] Examples of polyester resins include polyethylene terephthalate resins and polyethylene naphthalate resins.

[0069] Examples of acrylic resins include polymethyl methacrylate resins.

[0070] The polysulfone resin includes polyethersulfone.

[0071] Examples of vinyl resins include polyvinylidene chloride resins, polyvinyl alcohol resins, ethylene vinyl alcohol resins, syndiotactic polystyrene resins, cycloolefin resins, and polymethylpentene resins.

[0072] Among these, cellulose ester resins, cycloolefin resins, polycarbonate resins, and polysulfone resins are preferred, and cellulose ester resins having a structure represented by the following general formula (1) are more preferred, which facilitates the production of an asymmetric porous carbon dioxide separation membrane.

[0073]

[0074] [In general formula (1), R １ , R ２ and R ３ are each independently a hydrogen atom, an acetyl group, a propionyl group, or a butyryl group, and n represents the degree of polymerization.

[0075] The degree of polymerization n is the number of each repeating structure, and is, for example, about 20 to 500, preferably about 81 to 500, more preferably about 85 to 400, and particularly preferably about 90 to 250.

[0076] R in each repeating structure １ , R ２ and R ３ may be the same or different.

[0077] When the degree of substitution of acetyl groups in the cellulose ester resin is X and the sum of the degrees of substitution of propionyl groups and butyryl groups is Y, it is preferable that X and Y satisfy the following formulas (I) and (II): 2.0≦X+Y≦2.6 (formula (I)) and 0.1≦Y≦1.2 (formula (II)).

[0078] X+Y is called the total degree of acyl substitution. The total degree of acyl substitution is preferably 2.0 to 2.6. When the total degree of acyl substitution is 2.0 to 2.6, the cellulose ester resin becomes easily soluble in a solvent, making it suitable for solution casting.

[0079] The resin content in the dope is preferably 10 to 35% by mass, more preferably 15 to 25% by mass. When the content is 10% by mass or more, the drying load after casting onto a support can be reduced. When the content is 15% by mass or more, the drying load after casting onto a support can be further reduced. When the content is 35% by mass or less, the load during filtration is reduced and filtration accuracy is improved. When the content is 25% by mass or less, the load during filtration is further reduced and filtration accuracy is further improved.

[0080] The dope may contain other components such as a plasticizer in addition to the solvent and the resin.

[0081] [Carbon dioxide separation membrane] Fig. 2 is an SEM image of a cross section of a carbon dioxide separation membrane 4 produced by the present invention. As shown in Fig. 2, the carbon dioxide separation membrane 4 is an asymmetric porous membrane having a dense layer 4A that contributes to separation and a porous layer 4B that functions as a support layer that provides mechanical strength.

[0082] From the viewpoint of ease of handling, the thickness of the carbon dioxide separation membrane 4 is preferably 10 to 200 μm, more preferably 20 to 100 μm.

[0083] [Method for manufacturing a separation membrane module] The method for manufacturing a separation membrane module of the present invention includes a step of manufacturing a carbon dioxide separation membrane 4 by the above-described method for manufacturing a carbon dioxide separation membrane 4. The method for manufacturing a separation membrane module of the present invention may include, in addition to the step of manufacturing the carbon dioxide separation membrane 4, a step of manufacturing other components, a step of combining components together, and the like, as appropriate.

[0084] FIG. 3 is a partially cutaway schematic diagram showing an example of a separation membrane module 50. As shown in FIG. 3, the separation membrane module 50 has, as its basic structure, a permeate gas collecting pipe 52, one or more laminates 54, a covering layer 56, and an anti-telescope plate 58. The one or more laminates 54 are wrapped around the permeate gas collecting pipe 52. The covering layer 56 covers the outermost periphery of the laminates 54. The anti-telescope plates 58 are attached to both ends of the unit including the permeate gas collecting pipe 52, the laminates 54, and the covering layer 56.

[0085] The separation membrane module 50 separates a raw material gas 60 containing carbon dioxide, which is supplied from one end 50A side thereof, into carbon dioxide 62 and other gases 64, and discharges them separately from the other end 50B side.

[0086] The permeation gas collection pipe 52 is a cylindrical pipe with a plurality of through holes 52A formed in its pipe wall. One end (the end 50A side) of the permeation gas collection pipe 52 is closed. The other end (the other end 50B side) of the permeation gas collection pipe 52 is open, forming an outlet 66 through which carbon dioxide 62 that has passed through the stack 54 and collected through the through holes 52A is discharged.

[0087] The ratio of the through holes 52A to the surface area of ​​the permeation gas collecting pipe 52 (opening ratio) is preferably 1.5 to 80%, more preferably 3 to 75%, and even more preferably 5 to 70%. From a practical standpoint, the opening ratio is preferably 5 to 25%. When the opening ratio is equal to or greater than the respective lower limit values, the carbon dioxide 62 can be collected efficiently. When the opening ratio is equal to or less than the respective upper limit values, the strength of the tube can be increased and sufficient processability can be ensured.

[0088] The shape of the through-holes 52A is not particularly limited, but it is preferable that the through-holes 52A be circular holes having a diameter of 1 to 20 mm. The through-holes 52A are preferably uniformly arranged on the surface of the permeation gas collecting pipe 52.

[0089] The coating layer 56 is formed of a blocking material capable of blocking the raw material gas 60 passing through the separation membrane module 50. The blocking material preferably has heat resistance and moisture resistance. "Heat resistance" means that the shape before storage is maintained even after storage for two hours in an environment of 80°C or higher, and no visible curl due to thermal shrinkage or thermal melting occurs. "Moisture resistance" means that the shape before storage is maintained even after storage for two hours in an environment of 40°C and 80% RH, and no visible curl due to thermal shrinkage or thermal melting occurs.

[0090] The anti-telescope plate 58 has an outer annular portion 58A, an inner annular portion 58B, and radial spokes 58C. The outer annular portion 58A, the inner annular portion 58B, and the radial spokes 58C are preferably made of a material that is heat-resistant and moisture-resistant.

[0091] The laminate 54 is composed of a carbon dioxide separation membrane 4 folded in half and a supply gas channel member 70 sandwiched inside the carbon dioxide separation membrane 4. Sealing portions 74 are permeated into the carbon dioxide separation membrane 4 and the supply gas channel member 70. The carbon dioxide separation membrane 4 is adhesively sealed to a permeation gas channel member 76 on its radially inner side via the sealing portion 74. As described above, the carbon dioxide separation membrane 4 is an asymmetric porous membrane having a dense layer 4A, which is a portion that contributes to separation, and a porous layer 4B, which functions as a support layer that provides mechanical strength.

[0092] The number of laminates 54 wrapped around the permeate gas main pipe 52 is not particularly limited and may be one or more. Increasing the number of laminates 54 wrapped around the permeate gas main pipe 52 (number of laminates) can increase the membrane area of ​​the dense layer 4A. Increasing the membrane area of ​​the dense layer 4A can increase the amount of carbon dioxide 62 separated by one separation membrane module 50. The length of the laminate 54 may be increased to increase the membrane area of ​​the dense layer 4A.

[0093] The number of sheets of the laminate 54 is not particularly limited, but is preferably 50 or less, more preferably 45 or less, and still more preferably 40 or less. This makes it easier to wind the laminate 54 and improves processability.

[0094] The width of the laminate 54 is not particularly limited, but is preferably 50 to 10,000 mm, more preferably 60 to 9,000 mm, and even more preferably 70 to 8,000 mm. Furthermore, from the viewpoint of practicality, the width of the laminate 54 is preferably 200 to 2,000 mm. By ensuring that the width of the laminate 54 is equal to or greater than the respective lower limit values, it is possible to ensure an effective film area of ​​the dense layer 4A even when a resin is applied (sealed). By ensuring that the width of the laminate 54 is equal to or less than the respective upper limit values, it is possible to maintain the horizontality of the winding core and prevent winding slippage.

[0095] FIG. 4 is a cross-sectional perspective view showing a portion of a cylindrically wound body in which laminates 54 are wound around a permeation gas collection pipe 52. FIG. 4 schematically shows the entire width of the cylindrically wound body, with the central portion shortened. As shown in FIG. 4 , the laminates 54 are bonded together via sealing portions 80 that have permeated the carbon dioxide separation membranes 4, and are stacked around the permeation gas collection pipe 52. Specifically, the laminate 54 is stacked, in order from the permeation gas collection pipe 52 side, with a permeation gas flow path member 76, a carbon dioxide separation membrane 4, a feed gas flow path member 70, and a carbon dioxide separation membrane 4. A source gas 60 is supplied from the end of the feed gas flow path member 70. Carbon dioxide 62 from the supplied source gas 60 permeates through the carbon dioxide separation membrane 4, which is partitioned by the coating layer 56, and is separated. The separated carbon dioxide 62 is collected in the permeation gas collection pipe 52 via the permeation gas flow path member 76 and the through-hole 52A and is recovered from an outlet 66 connected to the permeation gas collection pipe 52. The remaining gas 64 from which the carbon dioxide 62 has been separated is discharged from the supply gas channel member 70 on the side where the discharge port 66 is provided or from the end of the carbon dioxide separation membrane 4 .

[0096] 5 is a schematic diagram showing the state before the laminate 54 is wrapped around the permeable gas main pipe 52. FIG. 5 shows an example of the formation regions of the sealing portions 74 and 80. The sealing portions 80 bond and seal the carbon dioxide separation membrane 4 and the permeable gas channel member 76 together when the laminate 54 is wrapped around the permeable gas main pipe 52 in the direction of arrow R in the figure. On the other hand, the sealing portions 74 bond and seal the carbon dioxide separation membrane 4 and the permeable gas channel member 76 together even before the laminate 54 is wrapped around the permeable gas main pipe 52.

[0097] The sealing portion 74 has a circumferential sealing portion 74A and an axial sealing portion 74B. The sealing portion 80 has a circumferential sealing portion 80A and an axial sealing portion 80B. The circumferential sealing portions 74A and 80A seal both side ends of the carbon dioxide separation membrane 4 and the permeable gas channel member 76 along the circumferential direction of the permeable gas manifold 52. The axial sealing portions 74B and 80B seal the circumferential ends of the carbon dioxide separation membrane 4 and the permeable gas channel member 76.

[0098] The circumferential sealing portion 74A and the axial sealing portion 74B are connected, and the sealing portion 74 as a whole has an envelope shape with an open circumferential end between the carbon dioxide separation membrane 4 at the start of winding and the permeate gas channel member 76. A flow path P1 is formed between the circumferential sealing portion 74A and the axial sealing portion 74B, through which the carbon dioxide 62 that has permeated the carbon dioxide separation membrane 4 flows to the through-hole 52A. Similarly, the circumferential sealing portion 80A and the axial sealing portion 80B are connected, and the sealing portion 80 as a whole has an envelope shape with an open circumferential end between the carbon dioxide separation membrane 4 at the start of winding and the permeate gas channel member 76. A flow path P2 is formed between the circumferential sealing portion 80A and the axial sealing portion 80B, through which the carbon dioxide 62 that has permeated the carbon dioxide separation membrane 4 flows to the through-hole 52A.

[0099] As described above, the method for producing a carbon dioxide separation membrane of the present invention is a method for producing an asymmetrically porous carbon dioxide separation membrane, and uses evaporation-induced phase separation. The method for producing a carbon dioxide separation membrane of the present invention includes a casting step, a drying step after the casting step, and a winding step after the drying step. In the casting step, a dope, which is a composition in which a resin is dissolved in a mixed solvent containing a good solvent having a boiling point of 100°C or less and a poor solvent having a boiling point of 120°C or less, is cast onto a support to form a web. In the drying step, the web is dried. In the winding step, the dried web is wound up as a carbon dioxide separation membrane. This method allows an asymmetrically porous carbon dioxide separation membrane to be produced with little carbon dioxide emissions.

[0100] In the method for producing a carbon dioxide separation membrane of the present invention, it is preferable to make the temperatures of the upper and lower surfaces of the dope different in the casting step, which makes it easier to change the ratio of the poor solvent to the good solvent in the thickness direction of the dope and to form an asymmetric porous membrane.

[0101] The method for producing a carbon dioxide separation membrane of the present invention preferably includes a plurality of drying steps at different drying temperatures, which facilitates the formation of an asymmetric porous membrane.

[0102] In the method for producing a carbon dioxide separation membrane of the present invention, the total time for drying the dope or web at a temperature of 50° C. or higher from the casting step to the winding step is preferably 100 minutes or less, which reduces the energy required for drying and the amount of carbon dioxide emitted.

[0103] From the viewpoint of reducing the environmental load, the mixed solvent preferably contains a polar solvent as a poor solvent.

[0104] The ratio of the poor solvent in the mixed solvent is preferably in the range of 5 to 29% by mass, which allows the viscosity during solution casting to be controlled to an appropriate value and maintains productivity.

[0105] The resin is preferably a cellulose ester resin having the structure represented by the above general formula (1), which makes it easier to produce an asymmetric porous carbon dioxide separation membrane.

[0106] The method for producing a carbon dioxide separation membrane of the present invention preferably includes a stretching step of stretching the web after the casting step, which allows the pore size of the porous layer of the carbon dioxide separation membrane to be adjusted.

[0107] The method for producing a separation membrane module of the present invention includes a step of producing a carbon dioxide separation membrane by a method for producing a carbon dioxide separation membrane.

[0108] Although embodiments of the present invention have been described and illustrated in detail, the disclosed embodiments are for purposes of illustration and example only and not limitation, and the scope of the present invention should be interpreted by the following claims.

[0109] The present invention will be specifically described below with reference to examples, but the present invention is not limited thereto. In the following examples, unless otherwise specified, operations were carried out at room temperature (25°C). In the following examples, unless otherwise specified, "%" and "parts" mean "% by mass" and "parts by mass", respectively.

[0110] In the examples and comparative examples, the following resins were used. Cellulose acetate propionate "S-CAP" manufactured by Eastman Chemical Co. A cellulose ester resin having a structure represented by general formula (1) Degree of acetyl group substitution: 1.58 Degree of propionyl group substitution: 0.88 Total degree of acyl group substitution: 2.46 Cellulose acetate butyrate "CAB171-15" manufactured by Eastman Chemical Co. A cellulose ester resin having a structure represented by general formula (1) Degree of acetyl group substitution: 2.12 Degree of butyryl group substitution: 0.74 Total degree of acyl group substitution: 2.86 Diacetyl cellulose "CA394-60s" manufactured by Eastman Chemical Co. A cellulose ester resin having a structure represented by general formula (1) Degree of acetyl group substitution: 2.48 Total degree of acyl group substitution: 2.48 Triacetyl cellulose "KTM" manufactured by Daicel Corporation A cellulose ester resin having a structure represented by general formula (1) Degree of acetyl group substitution: 2.88 Total acyl group substitution degree: 2.88 Acrylic resin Methyl methacrylate (MMA) / N-phenylmaleimide (PMI) methyl acrylate (MA) copolymer MMA / PMI / MA = 80 / 10 / 10 (mass ratio) Glass transition temperature Tg: 125 ° C. Weight average molecular weight Mw: 2,000,000 Cycloolefin resin "Arton" (registered trademark) manufactured by JSR Corporation

[0111] [Production of Carbon Dioxide Separation Membrane of Example 1] A carbon dioxide separation membrane was produced by evaporation-induced phase separation (EIPS) as follows.

[0112] Dichloromethane (good solvent) and methanol (poor solvent) were mixed to prepare a mixed solvent. The ratio of methanol (poor solvent) in the mixed solvent was 26% by mass. Cellulose acetate propionate was added as a resin to the mixed solvent so that the resin content was 15% by mass. Trimethylolpropane tribenzoate was added as a plasticizer to the mixed solvent so that the resin content was 1% by mass relative to the resin. The mixture was heated and stirred to completely dissolve the resin in the mixed solvent. The mixture was filtered using Azumi Filter Paper No. 244 (manufactured by Azumi Filter Paper Co., Ltd.). A dope was thus obtained.

[0113] The film was produced using a production apparatus 1 shown in Fig. 1. The support 101a was an endless belt made of stainless steel with a mirror-finished surface, and had a length of 60 m and a width of 2500 mm.

[0114] The dope, kept at a temperature of 20°C, was uniformly cast onto the support 101a at a casting speed of 30 m / min. The set temperature of the support 101a was 40°C. Dry air at a temperature of 45°C and an air pressure of 500 Pa (air speed of 29 m / sec) was supplied to the dope during casting from the first heated air supplying device 101d and the second heated air supplying device 101e. The dope was cast for 2 minutes while the temperatures of the upper and lower surfaces of the dope were made different, to form a web.

[0115] The web was peeled off from the support 101a with a peeling roll 101g, and the peeling tension was set to 150 N / m.

[0116] Next, a first drying step was carried out in the first drying device 102. The total length of the region in the first drying device 102 where the web was dried was 100 m. The drying temperature in the first drying step was 50° C., and the drying time was 3 minutes.

[0117] Next, a stretching step was carried out in the stretching device 103. The total length of the region in which the web was stretched in the stretching device 103 was 40 m. A clip tenter was used as the tenter 103d in the stretching device 103. In the stretching step, dry air at 160°C was blown for 2 minutes.

[0118] Next, the second drying step and the third drying step were carried out in a second drying device 104 having a first unit and a second unit. The first unit carried out the second drying step, and the second unit carried out the third drying step. The total length of the region in the second drying device 104 where the web was dried was 1,000 m. The drying temperature in the second drying step was 129°C, and the drying time was 2 minutes. The drying temperature in the third drying step was 98°C, and the drying time was 16 minutes.

[0119] Next, a winding step was carried out by the winding device 105, and the carbon dioxide separation membrane, which was a dried web, was wound up.

[0120] By the above operations, a carbon dioxide separation membrane of Example 1 was obtained, having a width of 1500 mm, a thickness of 30 μm, a length of 1000 m, an MD stretch rate (expansion rate) of −10%, and a TD stretch rate (expansion rate) of −1.5%. The carbon dioxide separation membrane of Example 1 was an asymmetric porous membrane whose cross section had a structure similar to the SEM image shown in FIG.

[0121] [Production of carbon dioxide separation membranes of Examples 2 to 16, 18 to 19 and Comparative Examples 1 and 2] The carbon dioxide separation membranes of Examples 2 to 16, 18 to 19 and Comparative Examples 1 and 2 were produced in the same manner as in the production of the carbon dioxide separation membrane of Example 1, except that the following conditions were changed as shown in Tables I to IV. The carbon dioxide separation membranes of Examples 2 to 16, 18 to 19 and Comparative Examples 1 and 2 were all asymmetric porous membranes. - Type of good solvent - Type of poor solvent - Ratio of poor solvent in mixed solvent - Type of resin (two types used at a mass ratio of 1:1 in Examples 13 to 16) - Resin content in the dope before addition of plasticizer - Casting step time - Temperature and time of the first drying step - Temperature and time of the second drying step - Temperature and time of the third drying step

[0122] [Production of Carbon Dioxide Separation Membrane of Example 17] A four-neck flask equipped with a dry nitrogen gas inlet tube, a condenser, a Dean-Stark condenser filled with toluene, and a stirrer was used. 25.59 g (57.6 mmol) of 2,2-bis(3,4-dicarboxyphenyl)-1,1,1,3,3,3-hexafluoropropane dianhydride (manufactured by Daikin Industries, Ltd.) and 134 g of N,N-dimethylacetamide were added to the four-neck flask. This mixture was stirred at room temperature under a nitrogen stream. 19.2 g (60 mmol) of 4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl (manufactured by Daikin Industries, Ltd.) was added to the mixture, and the mixture was heated and stirred at 80°C for 6 hours. The external temperature was then raised to 190°C, and the water generated during imidization was azeotropically distilled off together with toluene. Heating, refluxing, and stirring were continued for 6 hours, after which no further water generation was observed. The mixture was heated for 7 hours while distilling off the toluene, and after distilling off the toluene, methanol was added to cause reprecipitation. The precipitate was dried to obtain a polyimide having a weight-average molecular weight of 140,000.

[0123] Dichloromethane (good solvent) and ethanol (poor solvent) were mixed in a pressure dissolution tank to prepare a mixed solvent. The ratio of ethanol (poor solvent) in the mixed solvent was 26% by mass. The polyimide prepared above was added to the mixed solvent. The mixture was heated and stirred to completely dissolve the resin in the mixed solvent. The mixture was filtered using Azumi Filter Paper No. 244 (manufactured by Azumi Filter Paper Co., Ltd.). This gave a dope.

[0124] Except for using the dope, a carbon dioxide separation membrane of Example 17 was produced in the same manner as in Example 2. The carbon dioxide separation membrane of Example 17 was an asymmetric porous membrane.

[0125] [Production of Carbon Dioxide Separation Membrane of Comparative Example 3] A carbon dioxide separation membrane was produced by the Robb-Srirayan method as follows.

[0126] N-methylpyrrolidone (a good solvent), 1,3-dioxolane (a good solvent), and acetone (a good solvent) were added to a dissolution tank in a mass ratio of 32:46:22. Triacetyl cellulose was added as a resin to a resin content of 15 mass%. Trimethylolpropane tribenzoate was added as a plasticizer to a resin content of 1 mass%. The mixture was heated and stirred to completely dissolve the resin in the mixed solvent. The mixture was filtered using Azumi Filter Paper No. 244 (manufactured by Azumi Filter Paper Co., Ltd.). A dope was thus obtained.

[0127] For film formation, a production apparatus 1 shown in Fig. 1 was modified to include an immersion bath between the casting apparatus 101 and the first drying apparatus 102. A polyester film was used as the support 101a.

[0128] The dope was uniformly cast onto the support 101a at a casting speed of 30 m / min. The set temperature of the support 101a was 40°C. Dry air at a temperature of 45°C and an air pressure of 500 Pa (air speed of 29 m / sec) was supplied to the dope during casting from the first heated air supplying device 101d and the second heated air supplying device 101e. The dope was cast for 9 minutes while the temperatures of the upper and lower surfaces of the dope were made different, to form a web.

[0129] Next, the web, still laminated on the support 101a (polyester film), was immersed in a water bath at 1°C for 10 minutes to be gelled. The gelled web was then annealed in a hot water bath at 80°C for 15 minutes. The annealed web was then removed from the hot water bath. During removal, the web was peeled from the support 101a (polyester film).

[0130] The peeled web was subjected to the first drying step, stretching step, second drying step, third drying step, and winding step in the same manner as in the production of the carbon dioxide separation membrane of Example 1, except that the conditions were appropriately changed to those shown in Tables I to IV.

[0131] By the above operations, a carbon dioxide separation membrane of Comparative Example 3 was obtained. The carbon dioxide separation membrane of Comparative Example 3 was an asymmetric porous membrane.

[0132] The drying temperature and drying time in each of the examples and comparative examples were set so as to minimize the amount of carbon dioxide discharged, on the condition that an asymmetric porous membrane was produced from each dope.

[0133] For each carbon dioxide separation membrane manufactured as described above, 100,000 m ２ The carbon footprint was calculated as the amount of carbon dioxide emitted [t] during the production of each unit. The calculation results are shown in Table IV.

[0134]

[0135]

[0136]

[0137]

[0138] The contents of the resin, poor solvent, and good solvent shown in the table are the contents in the dope before the addition of the plasticizer.

[0139] From the above results, it was confirmed that the method for producing a carbon dioxide separation membrane of the present invention can produce an asymmetric porous carbon dioxide separation membrane with a small amount of carbon dioxide discharged.

[0140] The present invention can be used in a method for manufacturing a carbon dioxide separation membrane and a method for manufacturing a separation membrane module.

[0141] REFERENCE SIGNS LIST 1 Production apparatus 101 Casting apparatus 102 First drying apparatus 103 Stretching apparatus 104 Second drying apparatus 105 Winding apparatus 2 Dope 3 Web 4 Carbon dioxide separation membrane 4A Dense layer 4B Porous layer 50 Separation membrane module

Claims

1. A method for manufacturing a carbon dioxide separation membrane that is an asymmetric porous membrane, which uses an evaporation-induced phase separation method and involves casting a dope, which is a composition obtained by dissolving a resin in a mixed solvent containing a good solvent with a boiling point of 100°C or lower and a poor solvent with a boiling point of 120°C or lower, onto a support to form a web (casting step), drying the web after the casting step (drying step), and winding up the carbon dioxide separation membrane, which is the dried body of the web, after the drying step (winding-up step). A method for manufacturing a carbon dioxide separation membrane.

2. The method for manufacturing a carbon dioxide separation membrane according to claim 1, wherein in the casting step, the temperatures of the upper and lower surfaces of the dope are made different.

3. The method for manufacturing a carbon dioxide separation membrane according to claim 1, which has a plurality of the drying steps with different drying temperatures.

4. The method for manufacturing a carbon dioxide separation membrane according to claim 1, wherein the total drying time at a temperature of 50°C or higher for the dope or the web is 100 minutes or less from the casting step to the winding-up step.

5. The method for manufacturing a carbon dioxide separation membrane according to claim 1, wherein the mixed solvent contains a polar solvent as the poor solvent.

6. The method for manufacturing a carbon dioxide separation membrane according to claim 1, wherein the ratio of the poor solvent in the mixed solvent is in the range of 5 to 29% by mass.

7. The method for producing a carbon dioxide separation membrane according to claim 1, wherein the resin is a cellulose ester resin having a structure represented by the following general formula (1). [In the general formula (1), R １ , R ２ and R ３ are each independently a hydrogen atom, an acetyl group, a propionyl group or a butyryl group. n represents the degree of polymerization.] 8. The method for manufacturing a carbon dioxide separation membrane according to claim 1, which has a stretching step of stretching the web after the casting step.

9. A method for manufacturing a separation membrane module, which has a step of manufacturing a carbon dioxide separation membrane by the method for manufacturing a carbon dioxide separation membrane according to any one of claims 1 to 8.

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