JP7220087B2 - Zeolite membrane composite, method for producing zeolite membrane composite, and separation method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a zeolite membrane composite, a method for producing a zeolite membrane composite, and a method for separating mixed substances using the zeolite membrane composite.

At present, various researches and developments are being made on applications such as separation of specific molecules and adsorption of molecules using the molecular sieve action of zeolite by forming a zeolite membrane on a support to form a zeolite membrane composite. ing. In addition, as one of the methods for producing a zeolite membrane composite, a porous support formed of a ceramic sintered body or the like is immersed in a raw material solution, hydrothermally synthesized to form a zeolite membrane on the support, and then A method is known for burning off the structure-directing agent in the zeolite membrane.

In Patent Document 1, in the production of a DDR type zeolite membrane, for the purpose of improving the separation performance of the zeolite membrane, the zeolite membrane after hydrothermal synthesis is heated at 400 ° C. to 550 ° C. to define the structure in the zeolite membrane. It is proposed to burn off as much of the agent (1-adamantaneamine) as possible.

On the other hand, in Patent Document 2, for the purpose of protecting the molecular sieve from damage due to contact with moisture and damage due to physical contact, an amount of a template agent (or its decomposition) effective to coat the catalytic sites within the molecular sieve is used. It has been proposed that the product) remain within the molecular sieve. The residual rate of the template agent in the molecular sieve is 30% by weight or more. The occupancy rate of the template agent in the porous structure of the molecular sieve is 10-90% by volume.

In addition, in Patent Document 3, for the purpose of improving the gas separation performance of the zeolite adsorbent, a barrier compound is inserted into the pore structure of the zeolite adsorbent to allow a specific gas in the mixed gas to enter the pores. Techniques have been proposed to increase the approach speed. The loading of the barrier compound is at least 10% by weight of the saturation loading.

JP 2010-158665 A Japanese Patent Publication No. 2003-501241 Japanese Patent Publication No. 2016-506292

By the way, in the molecular sieve of Patent Document 2, since a large amount of the template agent remains, the permeation performance of the molecular sieve may be greatly reduced. In addition, the zeolite adsorbent of Patent Document 3 has improved separation performance when separating carbon dioxide from methane, but the permeation amount of carbon dioxide is reduced. On the other hand, as in Patent Document 1, when the structure-directing agent in the zeolite membrane is removed, impurity gases with large molecular diameters (that is, gases not to be separated) enter the zeolite membrane during gas separation and permeate. Performance and/or separation performance may be degraded.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to realize a suitable permeation amount of a substance to be permeated through a zeolite membrane and to suppress penetration of impurities into the zeolite membrane.

The present invention is directed to zeolite membrane composites. A zeolite membrane composite according to a preferred embodiment of the present invention comprises a porous support and a zeolite membrane formed on the support. The zeolite membrane contains , as a residue, a carbonized part of the structure-directing agent, which is an organic substance . The carbon dioxide permeation amount of the zeolite membrane is 70% or more and 100% or less of the carbon dioxide permeation amount of the non-residual zeolite membrane, which is a zeolite membrane that does not contain carbonized residue of the structure-directing agent . The methane permeation amount/carbon tetrafluoride permeation amount ratio of the zeolite membrane is 105% or more and 140% or less of the methane permeation amount/carbon tetrafluoride permeation amount ratio of the non-residual zeolite membrane.

Preferably, the zeolite membrane has a maximum number of ring members of eight.

Preferably, the residual rate of the residue in the zeolite membrane is 0.6% by weight or more and 2.0% by weight or less.

Preferably, said residue contained in said zeolite membrane is carbon.

The present invention is also directed to a method for producing a zeolite membrane composite. A method for producing a zeolite membrane composite according to a preferred embodiment of the present invention includes a) the step of preparing seed crystals, b) the step of adhering the seed crystals on a porous support, and c) a raw material solution and forming a zeolite membrane on the support by growing zeolite from the seed crystal by hydrothermal synthesis; and d) heating the zeolite membrane to remove an organic substance from the zeolite membrane. and a step of partially removing the structure-directing agent and leaving part of the structure-directing agent carbonized inside the zeolite membrane as a residue. The carbon dioxide permeation amount of the zeolite membrane after the step d) is 70% of the carbon dioxide permeation amount of the non-residual zeolite membrane, which is a zeolite membrane that does not contain carbonized residue of the structure-directing agent. not less than 100% and not more than 100%. The methane permeation amount/carbon tetrafluoride permeation amount ratio of the zeolite membrane after the step d) is 105% or more and 140% or less of the methane permeation amount/carbon tetrafluoride permeation amount ratio of the non-residual zeolite membrane. is.

Preferably, the step d) comprises: d1) heating the zeolite membrane formed in the step c) in an inert gas atmosphere; and d2) oxidizing the zeolite membrane after the step d1). and heating in a gaseous atmosphere.

The present invention is also directed to a separation method. A separation method according to a preferred embodiment of the present invention includes a) the step of preparing the above-described zeolite membrane composite, b) supplying a mixed substance containing a plurality of types of gases or liquids to the zeolite membrane composite, separating highly permeable substances in the mixed substance from other substances by permeating them through the zeolite membrane composite.

Preferably, said mixture includes hydrogen, helium, nitrogen, oxygen, water, water vapor, carbon monoxide, carbon dioxide, nitrogen oxides, ammonia, sulfur oxides, hydrogen sulfide, sulfur fluoride, mercury, arsine, hydrogen cyanide, Contains one or more of carbonyl sulfide, C1-C8 hydrocarbons, organic acids, alcohols, mercaptans, esters, ethers, ketones and aldehydes.

INDUSTRIAL APPLICABILITY In the present invention, it is possible to achieve a suitable permeation amount of a substance to be permeated through a zeolite membrane, and to suppress the penetration of impurities into the zeolite membrane.

1 is a cross-sectional view of a zeolite membrane composite; FIG. FIG. 2 is a diagram showing the production flow of a zeolite membrane composite. FIG. 2 is a diagram showing the production flow of a zeolite membrane composite. FIG. 2 is a diagram showing the production flow of a zeolite membrane composite. FIG. 2 is a diagram showing the production flow of a zeolite membrane composite. FIG. 3 shows a separation device; FIG. 4 is a diagram showing the flow of separation of mixed substances;

FIG. 1 is a cross-sectional view of a zeolite membrane composite 1 according to one embodiment of the present invention. A zeolite membrane composite 1 includes a support 11 and a zeolite membrane 12 formed on the support 11 . In the example shown in FIG. 1, the support 11 is a substantially cylindrical monolithic support provided with a plurality of through holes 111 each extending in the longitudinal direction (that is, the vertical direction in the drawing). A cross section perpendicular to the longitudinal direction of each through-hole 111 (that is, cell) is, for example, substantially circular. In FIG. 1, the diameter of the through-holes 111 is drawn larger than the actual number, and the number of the through-holes 111 is drawn smaller than the actual number. The zeolite membrane 12 is formed on the inner surface of the through-hole 111 and covers substantially the entire inner surface of the through-hole 111 . In FIG. 1, the zeolite membrane 12 is drawn with a thick line.

The length of the support 11 (that is, the length in the vertical direction in the drawing) is, for example, 10 cm to 200 cm. The outer diameter of the support 11 is, for example, 0.5 cm to 30 cm. The distance between the central axes of adjacent through holes 111 is, for example, 0.3 mm to 10 mm. The surface roughness (Ra) of the support 11 is, for example, 0.1 μm to 5.0 μm, preferably 0.2 μm to 2.0 μm. The shape of the support 11 may be, for example, a honeycomb shape, a flat plate shape, a tubular shape, a cylindrical shape, a columnar shape, a polygonal columnar shape, or the like. When the support 11 has a tubular shape, the thickness of the support 11 is, for example, 0.1 mm to 10 mm.

In the present embodiment, the support 11 is porous and permeable to gases and liquids (that is, fluids), and the zeolite membrane 12 uses a molecular sieve action to identify a mixed fluid in which a plurality of types of substances are mixed. It is a molecular separation membrane that separates substances from For example, the zeolite membrane 12 may be used as a gas separation membrane that separates a specific gas from a mixed gas containing multiple types of gases. Also, the zeolite membrane 12 may be used as a liquid separation membrane that separates a specific liquid from a mixed liquid containing multiple types of liquids. The zeolite membrane 12 may be used as a separation membrane that separates a specific substance from a mixed fluid in which gas and liquid are mixed. Alternatively, the zeolite membrane 12 can also be used as a pervaporation membrane. The zeolite membrane composite 1 may also be used for other applications.

Various materials can be used for the support 11 as long as they have chemical stability in the step of forming the zeolite membrane 12 on the surface. Examples of materials for the support 11 include sintered ceramics, metals, organic polymers, glass, and carbon. Ceramic sintered bodies include alumina, silica, mullite, zirconia, titania, yttria, silicon nitride, and silicon carbide. Metals include aluminum, iron, bronze, stainless steel, and the like. Examples of organic polymers include polyethylene, polypropylene, polytetrafluoroethylene, polysulfone, and polyimide. In the present embodiment, support 11 contains at least one of alumina, silica and mullite.

The support 11 may contain an inorganic binder. At least one of titania, mullite, sinterable alumina, silica, glass frit, clay mineral, and sinterable cordierite can be used as the inorganic binder.

When the zeolite membrane 12 is used as a separation membrane, preferably the average pore size of the support 11 near the surface where the zeolite membrane 12 is formed is smaller than the average pore size at other sites. In order to realize such a structure, the support 11 has a multi-layer structure. When the support 11 has a multi-layered structure, the above materials can be used for each layer, and each layer may be the same or different. The average pore diameter of the support 11 can be measured with a mercury porosimeter, a perm porometer, a nanoperm porometer, or the like.

The average pore size of the support 11 is, for example, 0.01 μm to 70 μm, preferably 0.05 μm to 25 μm. The average pore size of the support 11 near the surface where the zeolite membrane 12 is formed is 0.01 μm to 1 μm, preferably 0.05 μm to 0.5 μm. Average pore size can be measured, for example, by a mercury porosimeter, a perm porosimeter or a nanoperm porosimeter. Regarding the pore size distribution over the entire surface and inside of the support 11, D5 is, for example, 0.01 μm to 50 μm, D50 is, for example, 0.05 μm to 70 μm, and D95 is, for example, 0.1 μm to 2000 μm. . The porosity of the support 11 near the surface where the zeolite membrane 12 is formed is, for example, 20% to 60%.

The support 11 has, for example, a multilayer structure in which a plurality of layers having different average pore diameters are laminated in the thickness direction. The average pore size and sintered grain size in the surface layer including the surface on which the zeolite membrane 12 is formed are smaller than the average pore size and sintered grain size in layers other than the surface layer. The average pore diameter of the surface layer of the support 11 is, for example, 0.01 μm to 1 μm, preferably 0.05 μm to 0.5 μm. When the support 11 has a multilayer structure, the above materials can be used for each layer. The materials of the multiple layers forming the multilayer structure may be the same or different.

The thickness of the zeolite membrane 12 is, for example, 0.05 μm to 30 μm, preferably 0.1 μm to 20 μm, more preferably 0.5 μm to 10 μm. Separation performance is improved by increasing the thickness of the zeolite membrane 12 . Thinning the zeolite membrane 12 increases the permeation rate. The surface roughness (Ra) of the zeolite membrane 12 is, for example, 5 μm or less, preferably 2 μm or less, more preferably 1 μm or less, and even more preferably 0.5 μm or less.

The type of zeolite constituting the zeolite membrane 12 is not particularly limited, but when the zeolite membrane 12 is used as a separation membrane, the maximum number of rings of the zeolite is 6 or 8 is preferred. More preferably, the maximum number of ring members in the zeolite membrane 12 is eight.

The zeolite membrane 12 is, for example, DDR type zeolite. In other words, the zeolite membrane 12 is zeolite whose structure code is "DDR" as defined by the International Zeolite Society. In this case, the zeolite constituting the zeolite membrane 12 has an intrinsic pore diameter of 0.36 nm×0.44 nm and an average pore diameter of 0.40 nm. The intrinsic pore size of the zeolite membrane 12 is smaller than the average pore size of the support 11 .

The zeolite membrane 12 is not limited to DDR type zeolite, and may be zeolite having other structures. The zeolite membrane 12 is, for example, AEI type, AEN type, AFN type, AFV type, AFX type, BEA type, CHA type, DDR type, ERI type, ETL type, FAU type (X type, Y type), GIS type, Zeolites of LEV type, LTA type, MEL type, MFI type, MOR type, PAU type, RHO type, SAT type, SOD type, etc. may be used. More preferably, for example, AEI type, AFN type, AFV type, AFX type, CHA type, DDR type, ERI type, ETL type, GIS type, LEV type, LTA type, PAU type, RHO type, SAT type zeolite, etc. is. More preferably, for example, AEI type, AFN type, AFV type, AFX type, CHA type, DDR type, ERI type, ETL type, GIS type, LEV type, PAU type, RHO type, SAT type zeolite, and the like.

The zeolite forming the zeolite membrane 12 contains, for example, Al as T atoms. As the zeolite constituting the zeolite membrane 12, a zeolite in which the atoms (T atoms) located at the center of the oxygen tetrahedron (TO ₄ ) constituting the zeolite are silicon (Si) and aluminum (Al), and the T atoms are Al and phosphorus (P), SAPO-type zeolite in which T atoms are Si, Al, and P, MAPSO-type zeolite in which T atoms are magnesium (Mg), Si, Al, and P, A ZnAPSO type zeolite in which T atoms are zinc (Zn), Si, Al, and P, or the like can be used. Some of the T atoms may be substituted with other elements.

The zeolite membrane 12 contains Si, for example. The zeolite membrane 12 may contain any two or more of Si, Al and P, for example. The zeolite membrane 12 may contain an alkali metal. The alkali metal is, for example, sodium (Na) or potassium (K). When the zeolite membrane 12 contains Si atoms, the Si/Al ratio in the zeolite membrane 12 is, for example, 1 or more and 100,000 or less. The Si/Al ratio is preferably 5 or more, more preferably 20 or more, still more preferably 100 or more, and the higher the better. The Si/Al ratio in the zeolite membrane 12 can be adjusted by adjusting the mixing ratio of the Si source and the Al source in the raw material solution, which will be described later.

Next, the production flow of the zeolite membrane composite 1 will be described with reference to FIG. First, seed crystals used for manufacturing the zeolite membrane 12 are prepared (step S11). The seed crystal is obtained, for example, from a DDR-type zeolite powder produced by hydrothermal synthesis and obtained from the zeolite powder. The zeolite powder may be used as it is as a seed crystal, or the seed crystal may be obtained by processing the powder by pulverization or the like.

Subsequently, the porous support 11 is immersed in the solution in which the seed crystals are dispersed to adhere the seed crystals to the support 11 (step S12). Alternatively, the seed crystals are attached to the support 11 by contacting a portion of the support 11 where the zeolite membrane 12 is to be formed with a solution in which the seed crystals are dispersed. Thus, a seed crystal-attached support is produced. The seed crystal may be attached to support 11 by other techniques.

The support 11 to which the seed crystals are attached is immersed in the raw material solution. The raw material solution is prepared by dissolving, for example, a Si source and a structure-directing agent (hereinafter also referred to as "SDA") in a solvent. The composition of the raw material solution is, for example, _1.0SiO2 :0.015SDA:0.12( _CH2 ) ₂ ( _NH2 ) ₂ . The SDA contained in the raw material solution is an organic substance. Alcohol such as ethanol may be used as the solvent for the raw material solution. As SDA, for example, 1-adamantanamine can be used.

Then, DDR type zeolite is grown using the seed crystals as nuclei by hydrothermal synthesis, thereby forming DDR type zeolite membrane 12 on support 11 (step S13). The temperature during hydrothermal synthesis is preferably 120 to 200°C, for example 160°C. The hydrothermal synthesis time is preferably 10 to 100 hours, for example 30 hours. At this time, the composition of the DDR type zeolite membrane 12 can be adjusted by adjusting the mixing ratio of the Si source and the Al source in the raw material solution.

After the hydrothermal synthesis is completed, the support 11 and the zeolite membrane 12 are washed with ion-exchanged water. The washed support 11 and zeolite membrane 12 are dried at 80° C., for example. When the support 11 and the zeolite membrane 12 are dried, the zeolite membrane 12 is heat-treated to partially burn off the SDA in the zeolite membrane 12 and penetrate the fine pores in the zeolite membrane 12 . At this time, part of the SDA in the zeolite membrane 12 remains as a carbonized residue inside the zeolite membrane 12 (step S14). The residue is derived from SDA, which is an organic matter, such as carbon (C). Here, carbon refers to a residue having a carbon content of 85% or more after heat treatment. Thereby, the zeolite membrane composite 1 described above is obtained.

In the zeolite membrane composite 1 obtained in step S14, the zeolite membrane 12 contains residues derived from organic substances. The residual rate of the residue in the zeolite membrane 12 is preferably 0.6% by weight to 2.0% by weight. The residue residual ratio is the ratio of the weight of the residue (that is, the SDA-derived residue) in the zeolite membrane 12 after step S14 to the weight of the zeolite membrane 12 . The residual percentage of the residue is more preferably 0.9 wt % to 1.3 wt %, still more preferably 1.0 wt % to 1.3 wt %.

The residual ratio of the residue in the zeolite membrane composite 1 is determined as follows. First, after step S14 is completed, the weight of the zeolite membrane composite 1 is measured, and the weight of the zeolite membrane 12 in which the residue remains is obtained by subtracting the weight of the support 11 from the measured value. Calculate Then, the weight of the residue is calculated by subtracting the weight of the zeolite membrane 12 assuming no residue from the weight of the zeolite membrane 12 in which the residue remains. The weight of the zeolite membrane 12 assuming that it does not contain the above-described residue is obtained by heating the zeolite membrane composite 1 after step S14 at, for example, 500° C. for 50 hours. is completely burned off, the weight is measured, and the weight of the support 11 is subtracted from the measured value. After that, the weight of the residue calculated as described above is divided by the weight of the zeolite membrane 12 when it is assumed that no residue is contained, thereby calculating the residual percentage of the residue. The residual ratio of residues derived from adsorbed organic substances, which will be described later, can also be obtained in the same manner.

When it is difficult to measure the weight of the support 11, the residual ratio of the residue is calculated by the following method. First, using a tool made of a material softer than the support 11, the zeolite membrane 12 is scraped out from the zeolite membrane composite 1 after step S14 and separated from the support 11 so that the residue remains inside. Then, the weight of the zeolite membrane 12 is calculated. Then, the weight of the residue is calculated by subtracting the weight of the zeolite membrane 12 assuming no residue from the weight of the zeolite membrane 12 in which the residue remains. The weight of the zeolite membrane 12 assuming that it does not contain the above-mentioned residue is obtained by heating the shaved zeolite membrane 12 at, for example, 500° C. for 50 hours to completely burn the residue in the zeolite membrane 12. It is obtained by measuring the weight after removal. After that, the weight of the residue calculated as described above is divided by the weight of the zeolite membrane 12 when it is assumed that no residue is contained, thereby calculating the residual percentage of the residue.

FIG. 3 is a diagram showing in detail the flow of the heat treatment in step S14 described above. In step S14, first, the zeolite membrane 12 formed in step S13 is heated in an inert gas atmosphere (step S141). As a result, approximately the entire amount of SDA in the zeolite membrane 12 is carbonized. At this point, carbonized SDA remains in the zeolite membrane 12 and has not been removed from the zeolite membrane 12 .

The inert gas atmosphere in step S141 is, for example, a nitrogen (N ₂ ) gas atmosphere. The heating temperature in step S141 is preferably 400°C to 600°C, more preferably 410°C to 550°C, and even more preferably 450°C to 500°C. The heating time is preferably 30 hours to 60 hours, more preferably 32 hours to 55 hours, still more preferably 35 hours to 50 hours.

After step S141, the zeolite membrane 12 is heated in an oxidizing gas atmosphere (step S142). As a result, the carbonized SDA in the zeolite membrane 12 is partially burned and removed, and part of the carbonized SDA remains in the zeolite membrane 12 as the residue described above.

The oxidizing gas atmosphere in step S142 is an atmosphere containing oxygen, for example, the atmosphere. The heating temperature in step S142 is preferably 400°C to 600°C, more preferably 410°C to 550°C, and even more preferably 420°C to 500°C. The heating time is preferably 30 hours to 60 hours, more preferably 32 hours to 55 hours, still more preferably 35 hours to 50 hours.

In step S14, it is not always necessary to perform heating twice with different heating conditions as in steps S141 and S142. For example, by heat-treating the zeolite membrane 12 formed in step S13 under a single heating condition, the SDA in the zeolite membrane 12 is partially burned and removed, and a part of the SDA is carbonized. may remain in the zeolite membrane 12 as a residue. In this case, the zeolite membrane 12 is heated in an oxidizing gas atmosphere (for example, in the atmosphere). The heating temperature is preferably 400°C to 600°C, more preferably 410°C to 550°C, still more preferably 420°C to 500°C. The heating time is preferably 30 hours to 60 hours, more preferably 32 hours to 55 hours, still more preferably 35 hours to 50 hours.

The zeolite membrane composite 1 containing the residue inside the zeolite membrane 12 does not necessarily have to be produced by the above production method (steps S11 to S14), and may be produced by another production method. For example, as shown in FIG. 4, the zeolite membrane 12 formed on the support 11 in steps S21 to S23, which are the same steps as steps S11 to S13 described above, is exposed to an oxidizing gas atmosphere (for example, in the atmosphere). ), the SDA inside the zeolite membrane 12 is almost completely burned off (step S24).

Subsequently, a gas or liquid containing an organic matter is applied to the zeolite membrane 12 and permeated through the zeolite membrane 12, thereby adsorbing the organic matter in the zeolite membrane 12 (step S25). After that, the zeolite membrane 12 is heat-treated to partially burn and remove the adsorbed organic matter from the zeolite membrane 12, and a part of the adsorbed organic matter is carbonized inside the zeolite membrane 12, and the residue derived from the organic matter is removed. (step S26). As a result, the zeolite membrane composite 1 containing organic matter-derived residues inside the zeolite membrane 12 can be obtained. In the zeolite membrane composite 1 manufactured in Steps S21 to S26, the residue residual ratio is the weight of the zeolite membrane 12 after Step S26 is completed, assuming that no residue is contained. It is the weight percentage of residue (ie, residue from adsorbed organics). The weight of the zeolite membrane 12 assuming no residue is obtained by the same method as above.

FIG. 5 is a diagram showing in detail the flow of the heat treatment in step S26 described above. In step S26, first, the zeolite membrane 12 to which the organic matter is adhered in step S25 is heated in an inert gas atmosphere (step S261). As a result, approximately the entire amount of adsorbed organic matter in the zeolite membrane 12 is carbonized. At this point, the carbonized adsorbed organic matter remains in the zeolite membrane 12 and has not been removed from the zeolite membrane 12 .

The inert gas atmosphere in step S261 is, for example, _N2 gas atmosphere. The heating temperature in step S261 is preferably 300°C to 600°C, more preferably 310°C to 550°C, and still more preferably 350°C to 500°C. The heating time is preferably 5 hours to 12 hours, more preferably 5 hours to 10 hours, still more preferably 6 hours to 8 hours.

After step S261, the zeolite membrane 12 is heated in an oxidizing gas atmosphere (step S262). As a result, the carbonized adsorbed organic matter in the zeolite membrane 12 is partially burned and removed, and part of the carbonized adsorbed organic matter remains in the zeolite membrane 12 as the above-described residue.

The oxidizing gas atmosphere in step S262 is an atmosphere containing oxygen, for example, the air. The heating temperature in step S262 is preferably 300°C to 600°C, more preferably 310°C to 550°C, and even more preferably 350°C to 500°C. The heating time is 5 hours to 12 hours, preferably 5 hours to 10 hours, and still more preferably 6 hours to 8 hours.

In step S26, it is not always necessary to perform heating twice with different heating conditions as in steps S261 and S262. For example, by heat-treating the zeolite membrane 12 with the organic matter adsorbed in step S25 under a single heating condition, the adsorbed organic matter in the zeolite membrane 12 is partially burned off, and part of the adsorbed organic matter is removed. After being carbonized, it may remain in the zeolite membrane 12 as a residue. In this case, the zeolite membrane 12 is heated in an oxidizing gas atmosphere (for example, in the atmosphere). The heating temperature is preferably 300°C to 600°C, more preferably 310°C to 550°C, still more preferably 350°C to 500°C. The heating time is 5 hours to 12 hours, preferably 5 hours to 10 hours, and still more preferably 6 hours to 8 hours.

Next, separation of a mixed substance using the zeolite membrane composite 1 will be described with reference to FIGS. 6 and 7. FIG. FIG. 6 is a diagram showing the separation device 2. As shown in FIG. FIG. 7 is a diagram showing the flow of separation of the mixed substance by the separation device 2. As shown in FIG.

In the separation device 2, a mixed substance containing multiple types of fluids (that is, gas or liquid) is supplied to the zeolite membrane composite 1, and a highly permeable substance in the mixed substance is allowed to permeate the zeolite membrane composite 1. separated from other substances by Separation in the separation device 2 may be performed, for example, for the purpose of extracting a highly permeable substance from a mixed substance, or for the purpose of concentrating a less permeable substance.

The mixed substance (that is, the mixed fluid) may be, as described above, a mixed gas containing multiple types of gas, or a mixed liquid containing multiple types of liquid. It may be a gas-liquid two-phase fluid containing.

In the separation device 2, the CO ₂ permeation amount (permeance) of the zeolite membrane composite 1 at 20° C. to 400° C. is, for example, 100 nmol/m ² ·s·Pa or more. In addition, the CO ₂ permeation amount/CH ₄ leakage amount ratio (permeance ratio) of the zeolite membrane composite 1 at 20° C. to 400° C. is, for example, 100 or more. The permeance and permeance ratio are for a CO ₂ partial pressure difference of 1.5 MPa between the feed side and the permeate side of the zeolite membrane composite 1 .

Mixed substances include, for example, hydrogen (H ₂ ), helium (He), nitrogen (N ₂ ), oxygen (O ₂ ), water (H ₂ O), water vapor (H ₂ O), carbon monoxide (CO), Carbon dioxide ( _CO2 ), Nitrogen oxides, Ammonia ( _NH3 ), Sulfur oxides, Hydrogen sulfide ( _H2S ), Sulfur fluoride, Mercury (Hg), Arsine ( _AsH3 ), Hydrogen cyanide (HCN), Sulfide Contains one or more of carbonyls (COS), C1-C8 hydrocarbons, organic acids, alcohols, mercaptans, esters, ethers, ketones and aldehydes.

Nitrogen oxides are compounds of nitrogen and oxygen. Nitrogen oxides mentioned above include, for example, nitric oxide (NO), nitrogen dioxide (NO ₂ ), nitrous oxide (also referred to as dinitrogen monoxide) (N ₂ O), dinitrogen trioxide (N ₂ O ₃ ), dinitrogen tetroxide (N ₂ O ₄ ), dinitrogen pentoxide (N ₂ O ₅ ), and other gases called NO _x (nox).

Sulfur oxides are compounds of sulfur and oxygen. The above sulfur oxides are gases called _SOx (socks) such as sulfur dioxide (SO ₂ ) and sulfur trioxide (SO ₃ ).

Sulfur fluoride is a compound of fluorine and sulfur. The sulfur fluorides mentioned above include, for example, disulfur difluoride (FSSF, S=SF ₂ ), sulfur difluoride (SF ₂ ), sulfur tetrafluoride (SF ₄ ), hexafluoride sulfur (SF ₆ ) or disulfur decafluoride (S ₂ F ₁₀ );

C1-C8 hydrocarbons are hydrocarbons having 1 or more and 8 or less carbons. The C3-C8 hydrocarbons may be straight chain compounds, side chain compounds and cyclic compounds. In addition, C3 to C8 hydrocarbons include saturated hydrocarbons (that is, those in which double bonds and triple bonds are not present in the molecule), unsaturated hydrocarbons (that is, those in which double bonds and/or triple bonds are present in the molecule). existing within). C1-C4 hydrocarbons are, for example, methane (CH ₄ ), ethane (C ₂ H ₆ ), ethylene (C ₂ H ₄ ), propane (C ₃ H ₈ ), propylene (C ₃ H ₆ ), normal butane (CH ₃ (CH ₂ ) ₂ CH ₃ ), isobutane (CH(CH ₃ ) ₃ ), 1-butene (CH ₂ =CHCH ₂ CH ₃ ), 2-butene (CH ₃ CH=CHCH ₃ ) or isobutene (CH ₂ = C( _CH3 ) ₂ ).

The organic acids mentioned above are carboxylic acids, sulfonic acids, and the like. Carboxylic acids are, for example, formic acid (CH ₂ O ₂ ), acetic acid (C ₂ H ₄ O ₂ ), oxalic acid (C ₂ H ₂ O ₄ ), acrylic acid (C ₃ H ₄ O ₂ ) or benzoic acid (C ₆ H ₅ COOH) and the like. Sulfonic acid is, for example, ethanesulfonic acid (C ₂ H ₆ O ₃ S). The organic acid may be a chain compound or a cyclic compound.

The aforementioned alcohols are, for example, methanol (CH ₃ OH), ethanol (C ₂ H ₅ OH), isopropanol (2-propanol) (CH ₃ CH(OH)CH ₃ ), ethylene glycol (CH ₂ (OH)CH _{2 (} OH)) or butanol ( _C4H9OH ), and the like.

Mercaptans are organic compounds having hydrogenated sulfur (SH) at the end, and are also called thiols or thioalcohols. The mercaptans mentioned above are, for example, methyl mercaptan (CH ₃ SH), ethyl mercaptan (C ₂ H ₅ SH) or 1-propanethiol (C ₃ H ₇ SH).

The esters mentioned above are, for example, formates or acetates.

The aforementioned ethers are, for example, dimethyl ether ((CH ₃ ) ₂ O), methyl ethyl ether (C ₂ H ₅ OCH ₃ ) or diethyl ether ((C ₂ H ₅ ) ₂ O).

The ketones mentioned above are, for _example , acetone (( _{CH3 ) 2CO} ), methyl ethyl ketone ( _{C2H5COCH3 )} or diethylketone (( _C2H5 ) _2CO ).

The aldehydes mentioned above are, for example, acetaldehyde (CH ₃ CHO), propionaldehyde (C ₂ H ₅ CHO) or butanal (butyraldehyde) (C ₃ H ₇ CHO).

In the following description, it is assumed that the mixed substance separated by the separating device 2 is a mixed gas containing multiple kinds of gases.

The separation device 2 includes a zeolite membrane composite 1 , a sealing portion 21 , an outer cylinder 22 , a sealing member 23 , a supply portion 26 , a first recovery portion 27 and a second recovery portion 28 . The zeolite membrane composite 1 , the sealing portion 21 and the sealing member 23 are housed inside the outer cylinder 22 . The supply portion 26 , the first recovery portion 27 and the second recovery portion 28 are arranged outside the outer cylinder 22 and connected to the outer cylinder 22 .

The sealing part 21 is a member attached to both ends of the support 11 of the zeolite membrane composite 1 in the longitudinal direction to cover and seal both ends of the support 11 in the longitudinal direction. The sealing portion 21 prevents the inflow and outflow of gas from the both end faces of the support 11 . The sealing portion 21 is, for example, a plate-like member made of glass. The material and shape of the sealing portion 21 may be changed as appropriate. Both longitudinal ends of the through hole 111 of the support 11 are not covered with the sealing portion 21 . Therefore, it is possible for the mixed gas to flow into and out of the through hole 111 from both ends.

The outer cylinder 22 is a substantially cylindrical cylindrical member. The longitudinal direction of the zeolite membrane composite 1 (that is, the horizontal direction in the drawing) is substantially parallel to the longitudinal direction of the outer cylinder 22 . A supply port 221 is provided at one end in the longitudinal direction of the outer cylinder 22 (that is, the left end in the figure), and a first discharge port 222 is provided at the other end. A second discharge port 223 is provided on the side surface of the outer cylinder 22 . The internal space of the outer cylinder 22 is a closed space isolated from the space around the outer cylinder 22 .

The supply portion 26 is connected to the supply port 221 . The supply unit 26 supplies the mixed gas to the internal space of the outer cylinder 22 through the supply port 221 . The supply unit 26 is, for example, a blower that pumps the mixed gas toward the outer cylinder 22 . The blower includes a pressure control section that controls the pressure of the mixed gas supplied to the outer cylinder 22 . The first recovery section 27 is connected to the first discharge port 222 . The second recovery section 28 is connected to the second discharge port 223 . The first recovery part 27 and the second recovery part 28 are, for example, storage containers that store the gas drawn out from the outer cylinder 22 .

The sealing member 23 is provided between the outer surface of the zeolite membrane composite 1 (that is, the outer surface of the support 11) and the inner surface of the outer cylinder 22 near both ends in the longitudinal direction of the zeolite membrane composite 1. is placed across. The seal member 23 is a substantially annular member made of a gas-impermeable material. The sealing member 23 is, for example, an O-ring made of flexible resin. The sealing member 23 is in close contact with the outer surface of the zeolite membrane composite 1 and the inner surface of the outer cylinder 22 over the entire circumference. The space between the sealing member 23 and the outer surface of the zeolite membrane composite 1 and between the sealing member 23 and the inner surface of the outer cylinder 22 are sealed, and gas cannot pass therethrough.

When the mixed gas is to be separated, the zeolite membrane composite 1 is prepared by preparing the separation device 2 described above (step S31). Subsequently, the supply unit 26 supplies a mixed gas containing a plurality of types of gases having different permeability to the zeolite membrane 12 into the inner space of the outer cylinder 22 . For example, the main components of the mixed gas are _CO2 and _CH4 . The mixed gas may contain gases other than _CO2 and _CH4 . The pressure of the mixed gas supplied from the supply part 26 to the internal space of the outer cylinder 22 (that is, the introduction pressure) is, for example, 0.1 MPa to 10.0 MPa. The pressure (that is, permeation pressure) of the mixed gas recovered by the second recovery section 28 via the second discharge port 223 is, for example, atmospheric pressure. The pressure of the mixed gas recovered by the first recovery unit 27 through the first discharge port 222 (that is, the non-permeation pressure) is, for example, equivalent to the introduction pressure. The temperature at which the gas mixture is separated is, for example, 10°C to 150°C.

The mixed gas supplied from the supply part 26 to the outer cylinder 22 is introduced into each through-hole 111 of the support 11 from the left end of the zeolite membrane composite 1 in the drawing, as indicated by an arrow 251 . A highly permeable gas (for example, _CO2 , hereinafter referred to as a “highly permeable substance”) in the mixed gas passes through the zeolite membrane 12 provided on the inner surface of each through-hole 111 and the support It passes through the body 11 and is led out from the outer surface of the support 11 . Thereby, the highly permeable substance is separated from the low-permeable gas (eg, _CH4 , hereinafter referred to as "low-permeable substance") in the mixed gas (step S32). Gas (that is, highly permeable substance) discharged from the outer surface of the support 11 is recovered by the second recovery section 28 via the second discharge port 223 as indicated by arrow 253 .

Further, of the mixed gas, the gas excluding the gas that has permeated the zeolite membrane 12 and the support 11 (hereinafter referred to as “impermeable substance”) flows through each through-hole 111 of the support 11 from the left to the right in the figure. , and is recovered by first recovery section 27 via first discharge port 222 as indicated by arrow 252 . The impermeable substance may include a highly permeable substance that has not permeated the zeolite membrane 12, in addition to the low-permeable substance described above.

Next, Examples 1 to 8 and Comparative Examples 1 to 6 showing the relationship between the residue in the zeolite membrane 12 and the permeation performance and separation performance of the zeolite membrane 12 will be described with reference to Tables 1 and 2. . In Table 2, part of Table 1 is shown again to facilitate understanding of the table.

Table 2 shows the measurement results of the CO ₂ permeation amount and the CH ₄ permeation amount/CF ₄ permeation amount ratio for the zeolite membranes 12 of Examples 1 to 8 and the zeolite membranes of Comparative Examples 1 to 6. The measurement was performed using the separation device 2 described above.

The CO ₂ permeation _amount and _the CH ₄ permeation amount/CF ₄ permeation amount ratio were measured using _a single component of each gas (CO ₂ , CH ₄ or CF ₄ ) was obtained from the amount of permeation. When measuring the permeation amount of each gas, each gas was supplied from the supply unit 26 of the separation device 2 into the outer cylinder 22 at an introduction pressure of 0.1 MPa. Then, the amount of each gas recovered in the second recovery section 28 per unit time was obtained as the permeation amount of each gas (CO ₂ , CH ₄ or CF ₄ ). Here, the pressure of the mixed gas recovered by the second recovery section 28 via the second discharge port 223 (that is, permeation pressure) was atmospheric pressure. The pressure of the mixed gas recovered by the first recovery section 27 through the first discharge port 222 (that is, non-permeation pressure) was 0.1 MPa. The temperature at which the amount of permeation of each gas was measured was room temperature. Further, the CH ₄ permeation amount/CF ₄ permeation amount ratio was calculated by dividing the CH ₄ permeation amount obtained by the above method by the CF ₄ permeation amount obtained by the above method.

"P (CO ₂ )/P0 (CO ₂ )" in Table 2 is the ratio of the CO ₂ permeation amount of the zeolite membrane of each example and each comparative example to the CO ₂ permeation amount of the zeolite membrane of Comparative Example 1. Yes, and will be referred to as "relative transmittance" in the following description. "α(CH ₄ /CF ₄ )/α0(CH ₄ /CF ₄ )" in Table 2 indicates the CH ₄ permeation amount/CF ₄ permeation amount ratio of the zeolite membrane of Comparative Example 1 for each example and each comparison It is the ratio of the CH ₄ permeation amount/CF ₄ permeation amount ratio of the zeolite membrane of the example, and is referred to as the “relative separation rate” in the following description. The molecular diameter of _CO2 is 0.33 nm, the molecular diameter of _CH4 is 0.38 nm, and the molecular diameter of _CF4 is 0.47 nm.

In Comparative Example 1, during the production of the zeolite membrane composite, the SDA contained in the zeolite membrane was almost completely burned off by heat treatment. Therefore, the residual rate of residues in the zeolite membrane was substantially 0%. That is, the zeolite membrane of Comparative Example 1 is a zeolite membrane that does not substantially contain organic matter-derived residues inside, and is hereinafter referred to as a "non-residual zeolite membrane". Comparative Example 1 was heated once, and the heating temperature and heating time were 500° C. and 50 hours, respectively.

In Comparative Example 2, Examples 1 to 4, and Comparative Example 3, the SDA contained in the zeolite membrane was partially burned and removed by heat treatment during the production of the zeolite membrane composite, and part of the SDA was carbonized. It remained as a residue inside the zeolite membrane above (step S14). The number of times of heating in Comparative Example 2, Examples 1 to 4, and Comparative Example 3 was two. The heating temperature and heating time in the first inert gas atmosphere were 460° C. and 40 hours, respectively. The heating time in the second heat treatment was 400° C. and 50 hours in Comparative Example 2, 420° C. and 40 hours in Example 1, 440° C. and 40 hours in Example 2, and 440° C. and 40 hours in Example 3. 440° C. and 42 hours, Example 4 at 450° C. and 40 hours, and Comparative Example 3 at 460° C. and 40 hours.

The residual percentage of the residue in the zeolite membrane of Comparative Example 2 was 2.3% by weight. The relative permeability of Comparative Example 2 (that is, the value obtained by dividing the CO ₂ permeation amount of Comparative Example 2 by the CO ₂ permeation amount of the non-residual zeolite membrane of Comparative Example 1) was as small as 66%. Relative separation rate of Comparative Example 2 (that is, the value obtained by dividing the CH ₄ permeation amount/CF ₄ permeation amount ratio of Comparative Example 2 by the CH ₄ permeation amount/CF ₄ permeation amount ratio of the non-residual zeolite membrane of Comparative Example 1) was 104%. In the zeolite membrane of Comparative Example 2, the amount of CO ₂ permeation is thought to have decreased due to the large amount of residue.

The residual percentages of residues in the zeolite membranes 12 of Examples 1 to 4 were 1.9 wt %, 1.3 wt %, 0.9 wt % and 0.6 wt %, respectively. The relative transmittances of Examples 1-4 were 81%, 86%, 90% and 92%, respectively. The relative separation rates of Examples 1-4 were 121%, 140%, 124% and 108%, respectively. That is, the relative transmittance of Examples 1 to 4 was in the range of 70% to 100%, and the relative separation rate was in the range of 105% to 140%.

In Examples 1 to 4, the relative separation rate increased as the residue percentage increased from 0.6% by weight, and when the residue percentage was 1.3% by weight (Example 2), the maximum value was shown. After that, the relative separation rate decreased as the residual rate increased. This is believed to be due to the difference in change in CH ₄ and CF ₄ permeation with respect to change in retention rate. Specifically, the permeation amount of CF ₄ gradually decreases as the residual rate increases in the range where the residual rate is 1.3 wt% or less, and becomes approximately constant when the residual rate is greater than 1.3 wt%. On the other hand, it is believed that the permeation amount of CH ₄ gradually decreased as the residual rate increased in the range of 0.6 wt % to 2.0 wt %.

The residual percentage of the residue in the zeolite membrane of Comparative Example 3 was 0.4% by weight. Comparative Example 3 had a relative transmittance of 98% and a relative separation of 99%. That is, the CO ₂ permeation amount and the CH ₄ permeation amount/CF ₄ permeation amount ratio of Comparative Example 3 were approximately the same as those of Comparative Example 1. In the zeolite membrane of Comparative Example 3, since the amount of residue was small, it is considered that the CH ₄ permeation amount/CF ₄ permeation amount ratio did not increase.

In Examples 5 and 6, as in Examples 1 and 4, the SDA contained in the zeolite membrane 12 was partially burned off by heat treatment during the production of the zeolite membrane composite 1, and part of the SDA was removed. After being carbonized, it remained as a residue inside the zeolite membrane 12 (step S14). In Examples 5 and 6, the heating was performed once, the heating temperatures were 420° C. and 450° C., respectively, and the heating time was 42 hours.

The residual percentages of residues in the zeolite membranes 12 of Examples 5 and 6 were 1.9% by weight and 0.8% by weight, respectively. The relative transmittances of Examples 5 and 6 were 83% and 90%, respectively. The relative separation rates of Examples 5 and 6 were 111% and 106%, respectively. That is, the relative transmittance of Examples 5-6 was in the range of 70% to 100%, and the relative separation rate was in the range of 105% to 140%.

The relative transmittance and relative separation of Examples 5-6 are approximately equal to the relative transmittance and relative separation of Examples 1 and 4, respectively, which have the same percentage retention of residue. That is, when the SDA is burned off from the zeolite membrane 12 (step S14), regardless of whether the number of times of heating is one or two, the residual rate of the residue in the zeolite membrane 12 is 0.6% by weight to By setting the content to 2.0% by weight, the relative transmittance can be set within the range of 70% to 100%, and the relative separation rate can be set within the range of 105% to 140%.

In Comparative Example 4, after the organic matter was adsorbed on the zeolite membrane (step S25), substantially the entire amount of the adsorbed organic matter remained inside the zeolite membrane without burning and removing the adsorbed organic matter contained in the zeolite membrane. The relative transmittance of Comparative Example 4 was as small as 52%. The relative separation rate of Comparative Example 4 was 87%. It is considered that the zeolite membrane of Comparative Example 4 had a large amount of adsorbed organic matter, so that the amount of CO ₂ permeation decreased.

In Examples 7 and 8, after the organic matter was adsorbed on the zeolite membrane 12 (step S25), the adsorbed organic matter contained in the zeolite membrane 12 was partially burned and removed by heat treatment, and part of the adsorbed organic matter was carbonized. It was left as a residue inside the zeolite membrane 12 (step S26). The number of times of heating in Example 7 was two. The first heating temperature and heating time under the inert gas atmosphere were 380° C. and 8 hours, respectively, and the second heating temperature and heating time under the oxidizing gas atmosphere were 380° C. and 6 hours, respectively. there were. In Example 8, the number of times of heating was 1, the heating temperature was 380° C., and the heating time was 8 hours.

The residual percentages of residues in the zeolite membranes 12 of Examples 7 and 8 were 1.8% by weight and 1.7% by weight, respectively. The relative transmittances of Examples 7-8 were 83% and 84%, respectively. The relative separation rates of Examples 7-8 were 123% and 120%, respectively. That is, the relative transmittance of Examples 7-8 was in the range of 70% to 100%, and the relative separation rate was in the range of 105% to 140%.

The relative permeability and relative separation of Examples 7-8 are approximately equal to the relative permeability and relative separation, respectively, of Example 1, which has the same percentage retention of residue. That is, regardless of whether the residue contained in the zeolite membrane 12 is derived from SDA or is derived from adsorbed organic substances, the residue percentage of the residue in the zeolite membrane 12 is set to 0.6 wt. % to 2.0% by weight, the relative transmittance can be in the range of 70% to 100%, and the relative separation rate can be in the range of 105% to 140%.

In Comparative Example 5, when the zeolite membrane composite was produced, the SDA contained in the zeolite membrane was carbonized by heat treatment in an inert gas atmosphere, and remained as a residue inside the zeolite membrane. In Comparative Example 6, after organic matter was adsorbed on the zeolite membrane, the adsorbed organic matter contained in the zeolite membrane was carbonized by heat treatment in an inert gas atmosphere, and remained as a residue inside the zeolite membrane. In Comparative Examples 5 and 6, the zeolite membrane was not heat-treated in an oxidizing gas atmosphere. In Comparative Examples 5 and 6, the heating was performed once, the heating temperature was 460° C., and the heating time was 40 hours.

The residual percentages of residues in the zeolite membranes of Comparative Examples 5 and 6 were 12.6% by weight and 4.3% by weight, respectively. The relative transmittances of Comparative Examples 5 and 6 were as small as 0% and 53%, respectively. In the zeolite membranes of Comparative Examples 5 and 6, the amount of carbonized SDA or carbonized adsorbed organic matter is large, and/ _or the amount of carbonized SDA or carbonized adsorbed organic matter is large. .

The above-described Examples 1 to 8 are only for evaluating the performance of the zeolite membrane 12, and the substances separated by the zeolite membrane 12 in the separation device 2 or the like are CO ₂ , CH ₄ and CF ₄ . It is not limited.

As explained above, the zeolite membrane composite 1 includes the porous support 11 and the zeolite membrane 12 formed on the support 11 . The zeolite membrane 12 contains organic residue inside. As can be seen from Examples 1 to 8, the CO ₂ permeation amount of the zeolite membrane 12 is 70% or more and 100% of the CO ₂ permeation amount of the non-residual zeolite membrane, which is a zeolite membrane that does not contain organic matter-derived residues inside. % or less. In addition, the CH ₄ permeation amount/CF ₄ permeation amount ratio of the zeolite membrane 12 is 105% or more and 140% or less of the CH ₄ permeation amount/CF ₄ permeation amount ratio of the non-residual zeolite membrane.

Thus, in the zeolite membrane composite 1, by leaving a suitable size and a suitable amount of residue inside the zeolite membrane 12, the CO ₂ permeation of the zeolite membrane 12 is reduced compared to the non-residual zeolite membrane. It is possible to suppress penetration of CF ₄ , which has a larger molecular diameter than CO ₂ and CH ₄ , into the zeolite membrane 12 while suppressing a decrease in the amount. Therefore, in the zeolite membrane composite 1, a suitable permeation amount of a permeation target substance (for example, CO ₂ or the like), which is a target of selective permeation by the zeolite membrane 12, can be realized. In addition, since it is possible to suppress the infiltration of impurities (for example, CF ₄ ) having a larger molecular diameter than the substance to be permeated into the zeolite membrane 12, the permeation performance and separation performance of the substance to be permeated can be improved.

As described above, the maximum number of rings in the zeolite membrane 12 is preferably eight. As a result, selective permeation of a substance to be permeated such as CO ₂ having a relatively small molecular diameter can be suitably achieved, and the substance to be permeated can be efficiently separated from a mixed substance.

As described above, the residual rate of residues in the zeolite membrane 12 is preferably 0.6% by weight or more and 2.0% by weight or less. As a result, as can be seen from Examples 1 to 8, in the zeolite membrane 12, a more suitable permeation amount of the substance to be permeated can be realized, and the penetration of impurities into the zeolite membrane 12 can be further suppressed. can be done.

As mentioned above, the residue contained in the zeolite membrane 12 is preferably carbon (C). In this case, the residue can be easily generated by heating the zeolite membrane 12 containing the organic matter inside.

As described above, the method for producing the zeolite membrane composite 1 includes the step of preparing seed crystals (step S11), the step of attaching the seed crystals to the porous support 11 (step S12), A step of immersing the support 11 and growing zeolite from seed crystals by hydrothermal synthesis to form the zeolite membrane 12 on the support 11 (step S13); and a step of partially removing SDA and leaving part of the SDA as a residue inside the zeolite membrane 12 (step S14). The CO ₂ permeation amount of the zeolite membrane 12 after step S14 is 70% or more and 100% or less of the CO ₂ permeation amount of the non-residual zeolite membrane, which is a zeolite membrane containing no residue derived from organic substances. In addition, the CH ₄ permeation amount/CF ₄ permeation amount ratio of the zeolite membrane 12 after step S14 is 105% or more and 140% or less of the CH ₄ permeation amount/CF ₄ permeation amount ratio of the non-residual zeolite membrane. As a result, the zeolite membrane 12 capable of suitably permeating the substance to be permeated and suppressing the infiltration of impurities can be easily manufactured.

As described above, step S14 includes a step of heating the zeolite film 12 formed in step S13 in an inert gas atmosphere (step S141), and a step of heating the zeolite film 12 in an oxidizing gas atmosphere after step S141. It is preferable to include a step (step S142) of heating with. As a result, the amount of residue in the zeolite membrane 12 (that is, the residue ratio) can be easily controlled compared to the case where the residue is generated by a single heat treatment. Moreover, by thermally decomposing SDA in advance, the amount of residue in the zeolite membrane 12 can be reduced compared to the case where the residue is generated by one heat treatment. Therefore, it is possible to leave an appropriately sized residue that does not clog the relatively small pores of the 8-membered ring zeolite.

Specifically, after the entire amount of SDA is substantially uniformly carbonized in step S141, the carbonized SDA is burned and removed in step S142, so that the heating conditions in step S142 (that is, the heating temperature and the heating time) and the residual The relationship with the survival rate of objects is very high. In other words, the reproducibility of the residual rate is very high when the heating conditions in step S142 are the same. Therefore, as described above, by dividing the heat treatment into two stages, the amount of residue (that is, residual rate) in the zeolite membrane 12 can be easily controlled.

Further, in step S14, between step S141 and step S142, the weight of the residue in the zeolite membrane 12 (that is, SDA carbonized in step S141) is measured, and based on the measurement result, step S142 A step of adjusting the heating temperature and heating time may be performed. As a result, it is possible to improve the control accuracy of the amount of residue (that is, residual ratio) in the zeolite membrane 12 after step S142 is completed.

The method for producing the zeolite membrane composite 1 is not limited to steps S11 to S14 as described above. For example, another method for producing the zeolite membrane composite 1 includes a step of adsorbing an organic substance to the zeolite membrane 12 formed on the support 11 and from which SDA has been removed from the inside (step S25), and heating the zeolite membrane 12. Thereby, the organic matter is partially removed from the zeolite membrane 12, and a part of the organic matter remains inside the zeolite membrane 12 as a residue (step S26). The CO ₂ permeation amount of the zeolite membrane 12 after step S26 is 70% or more and 100% or less of the CO ₂ permeation amount of the non-residual zeolite membrane, which is a zeolite membrane that does not contain organic matter-derived residue inside. In addition, the CH ₄ permeation amount/CF ₄ permeation amount ratio of the zeolite membrane 12 after step S26 is 105% or more and 140% or less of the CH ₄ permeation amount/CF ₄ permeation amount ratio of the non-residual zeolite membrane. As a result, similarly to the above, the zeolite membrane 12 capable of favorably transmitting the substance to be permeated and suppressing the infiltration of impurities can be easily manufactured.

As described above, step S26 includes a step of heating the zeolite film 12 formed in step S25 in an inert gas atmosphere (step S261), and a step of heating the zeolite film 12 in an oxidizing gas atmosphere after step S261. It is preferable to include a step of heating by heating (step S262). As a result, similar to steps S141 and S142 described above, the amount and size of the residue in the zeolite membrane 12 can be easily controlled compared to the case where the residue is generated by one heat treatment. can be done.

Further, in step S26, similarly to step S14, between step S261 and step S262, the weight of the residue in the zeolite membrane 12 (that is, the adsorbed organic matter carbonized in step S261) and the like are measured and measured. Based on the result, the step of adjusting the heating temperature and heating time in step S262 may be performed. As a result, it is possible to improve the control accuracy of the amount of residue (that is, residual ratio) in the zeolite membrane 12 after step S262 is completed.

The above-described separation method includes a step of preparing the zeolite membrane composite 1 (step S31), and supplying a mixed substance containing a plurality of types of gases or liquids to the zeolite membrane composite 1 so that the mixed substance has high permeability. and a step of separating the substance from other substances by permeating the zeolite membrane composite 1 (step S32).

As described above, the zeolite membrane 12 can achieve a suitable permeation amount of the substance to be permeated, and can suppress the penetration of impurities into the zeolite membrane 12 . Therefore, the separation method can efficiently separate the mixed substance. In addition, the separation method includes hydrogen, helium, nitrogen, oxygen, water, water vapor, carbon monoxide, carbon dioxide, nitrogen oxides, ammonia, sulfur oxides, hydrogen sulfide, sulfur fluoride, mercury, arsine, hydrogen cyanide, sulfide It is particularly suitable for separating mixtures containing one or more of carbonyls, C1-C8 hydrocarbons, organic acids, alcohols, mercaptans, esters, ethers, ketones and aldehydes.

Various modifications can be made to the zeolite membrane composite 1, the method for producing the zeolite membrane composite 1, and the separation method described above.

For example, the maximum number of ring members of the zeolite membrane 12 may be smaller than eight or larger than eight.

The residual rate of organic matter-derived residues in the zeolite membrane 12 may be less than 0.6% by weight or greater than 2.0% by weight.

The organic substance-derived residue contained in the zeolite membrane 12 is not necessarily limited to carbon, and may be other substances.

In the method for producing the zeolite membrane composite 1, for example, the heat treatment may be performed three times or more under different heating conditions in step S14. The same applies to step S26.

In step S25, the zeolite membrane 12 on which the organic substances are adsorbed is not necessarily limited to the zeolite membrane 12 in production from which SDA has been almost completely removed. For example, by using the zeolite membrane 12 from which the internal SDA has been almost completely or partially removed at the time of manufacture for separation of mixed substances in the separation device 2 or the like, the organic matter is removed from the zeolite membrane 12 in the process of the separation. (step S25). Then, the used zeolite membrane 12 may be subjected to the heat treatment in step S26 to obtain the zeolite membrane 12 containing the residue inside. In this case, the heat treatment in step S26 is also recovery treatment for recovering the permeation performance of the zeolite membrane 12 .

In the separation device 2 and the separation method, substances other than the substances exemplified in the above description may be separated from the mixed substance.

The configurations in the above embodiment and each modified example may be combined as appropriate as long as they do not contradict each other.

The zeolite membrane composite of the present invention can be used, for example, as a gas separation membrane, and can also be used in various fields where zeolites are used, such as separation membranes for gases other than gases and adsorption membranes for various substances. be.

1 zeolite membrane composite 11 support 12 zeolite membrane S11 to S14, S21 to S26, S31 to S32, S141 to S142, S261 to S262 Step

Claims (8)

A zeolite membrane composite,
a porous support;
a zeolite membrane formed on the support;
with
The zeolite membrane contains a carbonized part of the structure-directing agent, which is an organic substance, as a residue inside ,
The carbon dioxide permeation amount of the zeolite membrane is 70% or more and 100% or less of the carbon dioxide permeation amount of the non-residual zeolite membrane, which is a zeolite membrane that does not contain a carbonized residue of the structure-directing agent ,
A zeolite characterized in that the methane permeation amount/carbon tetrafluoride permeation amount ratio of the zeolite membrane is 105% or more and 140% or less of the methane permeation amount/carbon tetrafluoride permeation amount ratio of the non-residual zeolite membrane. membrane complex. The zeolite membrane composite according to claim 1,
A zeolite membrane composite, wherein the zeolite membrane has a maximum number of ring members of 8. The zeolite membrane composite according to claim 1 or 2,
A zeolite membrane composite, wherein a residual rate of said residue in said zeolite membrane is 0.6% by weight or more and 2.0% by weight or less. The zeolite membrane composite according to any one of claims 1 to 3,
A zeolite membrane composite, wherein the residue contained in the zeolite membrane is carbon. A method for producing a zeolite membrane composite,
a) providing seed crystals;
b) depositing the seed crystals on a porous support;
c) a step of immersing the support in a raw material solution and growing zeolite from the seed crystals by hydrothermal synthesis to form a zeolite membrane on the support;
d) heating the zeolite membrane to partially remove the organic structure-directing agent from the zeolite membrane, and partially carbonize the structure-directing agent as a residue inside the zeolite membrane; a step of remaining;
with
The carbon dioxide permeation amount of the zeolite membrane after the step d) is 70% of the carbon dioxide permeation amount of the non-residual zeolite membrane, which is a zeolite membrane that does not contain carbonized residue of the structure-directing agent. not less than and not more than 100%,
The methane permeation amount/carbon tetrafluoride permeation amount ratio of the zeolite membrane after the step d) is 105% or more and 140% or less of the methane permeation amount/carbon tetrafluoride permeation amount ratio of the non-residual zeolite membrane. A method for producing a zeolite membrane composite, characterized by: A method for producing a zeolite membrane composite according to claim 5,
The step d) is
d1) a step of heating the zeolite membrane formed in step c) in an inert gas atmosphere;
d2) a step of heating the zeolite membrane in an oxidizing gas atmosphere after the step d1);
A method for producing a zeolite membrane composite, comprising: A separation method comprising:
a) providing a zeolite membrane composite according to any one of claims 1 to 4;
b) supplying a mixed substance containing multiple types of gases or liquids to the zeolite membrane composite, and separating a highly permeable substance in the mixed substance from other substances by permeating the zeolite membrane composite; process and
A separation method comprising: The separation method according to claim 7 ,
The mixture includes hydrogen, helium, nitrogen, oxygen, water, water vapor, carbon monoxide, carbon dioxide, nitrogen oxides, ammonia, sulfur oxides, hydrogen sulfide, sulfur fluoride, mercury, arsine, hydrogen cyanide, carbonyl sulfide, A separation method comprising one or more of C1 to C8 hydrocarbons, organic acids, alcohols, mercaptans, esters, ethers, ketones and aldehydes.

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