JP6899739B2 - Gas separator and gas separator - Google Patents

Description

Embodiments of the present invention relate to gas separators and gas separators.

In air-conditioning technology for home air conditioners and the like, technological advances have been made in terms of both refrigerant and energy efficiency, and a more comfortable living environment is required accordingly. For this reason, not only temperature but also air conditioners such as humidity control, ventilation, air flow adjustment, and air purification are becoming more multifunctional. Improving energy efficiency has become the most important issue due to the recent energy shortage. Even in hot and humid Asian countries, humidity control, especially dehumidification, is considered to be important as living standards improve, and air conditioning with a small environmental load is required by doing this with energy saving. Dehumidification by refrigerant cooling using a compressor or the like, which is currently the mainstream, requires a large amount of energy because the air is cooled to condense water vapor and the cooled air is reheated to adjust the temperature. Therefore, since the power consumption increases, the large environmental load has become an issue.

Gas separators such as desiccant air conditioners are more energy efficient than refrigerant-type dehumidification because they adsorb indoor moisture with a moisture absorber that uses a moisture absorbing material that adsorbs water vapor, then warms it and discharges it outdoors. .. As the moisture absorbing material, for example, a material in which a porous body such as a ceramic porous body or a zeolite is impregnated and supported with a deliquescent substance composed of chlorides or bromides such as sodium, lithium, calcium and magnesium is known. However, since the moisture absorbing material is saturated by continuously adsorbing water, a regeneration process is required. The regenerating treatment of the moisture absorbing material is performed by heating the moisture absorbing material to discharge water. It is inefficient to use the moisture absorbing material regeneration treatment in combination with cooling.

On the other hand, in order to dehumidify air used in instrumentation equipment and the like, a dehumidifying device using a hygroscopic film such as a zeolite membrane is known. The dehumidifying device using the zeolite membrane is excellent in the hygroscopic performance of water vapor, but has a problem that the permeation flow rate and permeation rate of water vapor are small. Since it is necessary to secure the flow rate and the flow velocity for air conditioning applications and the like, it is not possible to construct a practical air conditioning device with a dehumidifying device using a zeolite membrane. When zeolite is used as a moisture absorbing material, it has been studied to use a powder molded product other than the membrane. However, in the molded product using the binder, the particle surface is covered with the binder, so that the original moisture absorption performance of zeolite cannot be obtained. Although the green compact obtained by compressing and solidifying the zeolite powder is excellent in initial performance, it deteriorates significantly with the passage of time, and it is not possible to construct a practical air conditioner like the zeolite membrane.

As an energy-saving and low-cost method to replace the current air-conditioning method, a continuous dehumidification method using a steam separator that does not require regeneration treatment is being studied. As the structure of the humidity control device using the water vapor separator, the humidity of the gas separator in which a liquid absorbent such as an aqueous solution of lithium chloride is filled between two water vapor permeable films using polyethylene, fluororesin or the like is controlled. Examples thereof include a structure arranged between a space such as indoors and a space such as outdoors, and water vapor is exchanged between indoor air and a liquid absorber via a water vapor permeable film. However, the water vapor permeable membrane is easily damaged, and in this method, the moving speed of water vapor is slow, so that it is difficult to efficiently dehumidify.

Further, for example, as an inorganic separation membrane that separates water from an aqueous alcohol solution or separates a different gas from a mixed gas of water vapor and a gas different from the same, on one surface of a support made of a porous material, 30 to 30 to A separation membrane provided with a porous thin film layer in which fibrous alumina particles having an average aspect ratio of 5000 are stacked in parallel in one direction has been proposed. In such a separation membrane, for example, fibrous alumina particles having an average minor axis of 1 to 10 nm and an average major axis of 100 to 10,000 nm are used, and pores provided between the stacked fibrous alumina particles are formed. It is used to obtain liquid and gas separation performance. However, in the structure in which the fibrous alumina particles are simply stacked on the porous support, cracks occur in the arrangement direction of the fibrous alumina particles in the porous thin film layer composed of the fibrous alumina particles, and the support provides the fibrous alumina particles. There is a risk of gradual peeling. Therefore, there is a problem that the separation performance cannot be continuously obtained.

Japanese Unexamined Patent Publication No. 2016-176674 Japanese Unexamined Patent Publication No. 2003-336863 Japanese Patent No. 5621965 Japanese Unexamined Patent Publication No. 2016-123893

The problem to be solved by the present invention is a gas separator capable of obtaining performance, strength, reliability, etc. applicable to air conditioning and the like while maintaining practical gas separation performance, and a gas using the gas separator. The purpose is to provide a separation device.

The gas separator of the embodiment is a porous base material having a first surface, a second surface facing the first surface, and pores leading from the first surface to the second surface. And at least one of the first surface and the second surface of the porous base material, a porous film provided so as to close at least a part of the pores and containing a fibrous inorganic substance is provided. However, a part of the porous film penetrates along the inner wall of the pores of the porous substrate, and the average penetration depth of the porous film into the pores is the average of the porous film. membrane Ri der least thickness, the porous substrate, aluminum, silicon, zinc, magnesium, calcium, strontium, barium, titanium, zirconium, nickel, cobalt, iron, chromium, or copper oxide, nitride, carbide , And a porous ceramic containing at least one selected from the group consisting of silicate, and the fibrous inorganic substance is aluminum, silicon, zinc, magnesium, calcium, strontium, barium, titanium, zirconium, nickel, cobalt. Includes at least one selected from the group consisting of oxides, nitrides, carbides, hydroxides, silicates, carbonates, and phosphates, including hydrates of iron, chromium, or copper .

The gas separation device of the embodiment is provided so as to partition the first space, the second space leading to the first space, and the first space and the second space. The separation target gas in the second space so that the partial pressure of the gas separator of the form and the separation target gas in the second space is lower than the partial pressure of the separation target gas in the first space. It is a gas separation device including a gas pressure adjusting unit for adjusting the partial pressure of the above, and allowing the gas to be separated existing in the first space to permeate into the second space through the gas separator.

It is a figure which shows the structure of the gas separation apparatus of embodiment. It is sectional drawing which shows the schematic structure of the gas separator of the gas separator shown in FIG. It is a partial cross-sectional view schematically showing an example of the fine structure of the gas separator shown in FIG. It is a partial cross-sectional view schematically showing another example of the fine structure of the gas separator shown in FIG. It is sectional drawing which shows the use example of the gas separator shown in FIG. It is a figure which shows the 1st example which used the gas separation apparatus shown in FIG. 1 as a dehumidifying apparatus. It is a figure which shows the 2nd example which used the gas separation apparatus shown in FIG. 1 as a dehumidifying apparatus.

Hereinafter, the gas separator of the embodiment and the gas separator using the gas separator will be described with reference to the drawings. In each embodiment, substantially the same constituent parts may be designated by the same reference numerals, and the description thereof may be partially omitted. The drawings are schematic, and the relationship between the thickness and the plane dimensions, the ratio of the thickness of each part, etc. may differ from the actual ones. The terms indicating the up and down directions in the explanation may differ from the actual direction based on the gravitational acceleration direction.

(First Embodiment)
FIG. 1 shows the configuration of the gas separation device according to the embodiment. The gas separation device 1 shown in FIG. 1 is a subject of air or the like existing in the space to be treated (space to be treated), for example, containing a gas (gas to be separated) such as water vapor or an organic solvent-based gas (organic solvent vapor). It is a device that separates the gas to be separated from the treated gas and reduces the gas concentration in the space to be treated. The gas separation device 1 includes a separation chamber 2 constituting the first space S1, a decompression chamber 3 constituting the second space S2, and a connection path 4 connecting the separation chamber 2 and the decompression chamber 3 so as to communicate with each other. , A gas separator 5 arranged in a connecting path 4 so as to partition between the separation chamber 2 and the decompression chamber 3, a blower 6 for sending a gas to be processed containing a gas to be separated to the separation chamber 2, and a decompression chamber. A decompression pump 7 for depressurizing the inside of 4 is provided.

The separation chamber 2 has a suction port 8A and a discharge port 9A, and the suction port 8A is connected to the blower 6 via a pipe 10. The decompression chamber 3 has a suction port 8B and a discharge port 9B, and the discharge port 9B is connected to the decompression pump 7 via a pipe 11. By operating the blower 6 to the first space S1 in the separation chamber 2, a gas to be treated such as air containing a gas to be separated is sent through the pipe 10. The gas to be treated is, for example, from a room where the concentration of the gas to be separated such as water vapor or an organic solvent-based gas is reduced, inside an apparatus, inside a factory (closed space, etc.), a storage space, a storage space, etc. (not shown). It is introduced into the blower 6 via the pipe 12. The gas to be separated is separated in the separation chamber 2, and the gas to be treated whose gas concentration is reduced is returned to the space to be treated via the pipe 13.

In the second space S2 in the decompression chamber 3, the pressure in the separation chamber 2 (pressure in the first space S1) and the pressure in the decompression chamber 3 (in the second space S2) are generated by operating the decompression pump 7. The pressure is reduced so that there is a difference between the pressure and the pressure. Gases such as water vapor and organic solvent-based gas separated from the gas to be treated are discharged through the pipe 14 connected to the decompression pump 7. The separated gas (gas that has permeated into the decompression chamber 3) is released into the atmosphere or recovered as needed. A pipe 15 is connected to the suction port 8B of the decompression chamber 3 so as to depressurize while taking in external air or the like inside the decompression chamber 3. The pipe 15 may be provided with a valve (not shown) if necessary. Further, the pipe 15 can be omitted in some cases.

The gas separator 5 will be described with reference to FIGS. 2 to 4. FIG. 2 is a cross-sectional view showing a schematic structure of the gas separator 5, FIG. 4 is a partial cross-sectional view schematically showing an example of the microstructure of the gas separator 5, and FIG. 5 is another example of the microstructure of the gas separator 5. Is a partial cross-sectional view schematically showing. As shown in these figures, the gas separator 5 has a porous base material 21 and a porous membrane 22 provided on one surface of the porous base material 21. The porous base material 21 has an upper surface 21a, a lower surface 21b facing the upper surface 21a, and a plurality of pores (not shown in FIG. 2) leading from the upper surface 21a to the lower surface 21b. The porous film 22 is provided on at least one of the upper surface 21a and the lower surface 21b of the porous base material 21 so as to close at least a part of the plurality of pores of the porous base material 21. FIG. 2 shows a state in which the porous film 22 is formed on the upper surface 21a of the porous substrate 21, but the present invention is not limited to this, and the porous film 22 is provided on the lower surface 21b of the porous substrate 21. It may be provided on both surfaces of the upper surface 21a and the lower surface 21b.

The porous film 22 contains a fibrous inorganic substance, and is formed by depositing such a fibrous inorganic substance on the surface (at least one of the upper surface 21a and the lower surface 21b) of the porous base material 21. The porous film 22 has a contact surface 22a in contact with the porous base material 21 and an exposed surface 22b exposed to the outside. The porous film 22 has a plurality of micropores (not shown) provided in the gaps between the deposited fibrous inorganic substances, and at least a part of these micropores is from the contact surface 22a to the exposed surface 22b. I am familiar with. As will be described in detail later, the micropores provided in the porous membrane 22 form, for example, a wet seal to form a movement path for the gas to be separated, and the gas to be separated has a contact surface in the micropores. By moving from the exposed surface 22b or the exposed surface 22b toward the contact surface 22a, the gas to be separated, such as water vapor or an organic solvent-based gas, is separated from the gas to be treated. Wet seals with fine pores are formed as needed, and in some cases, water vapor and the like can be separated without forming a wet seal.

In the gas separator 5 of the embodiment, a part 22X of the porous membrane 22, in other words, a part of the fibrous inorganic substance constituting the porous membrane 22, is a porous base material as shown in FIGS. 3 and 4. It has penetrated into the pore 23 along the inner wall 23a of the pore 23 of the 21. The average penetration depth of the penetrating portion 22X of the porous film 22 into the pores 23 is set to be equal to or larger than the average film thickness of the porous film 22. By allowing a part 22X of the porous film 22 to penetrate into the pores 23 along the inner wall 23a more than the average thickness, the cracks in the porous film 22 and the porous base material 21 of the porous film 22 are formed. Peeling can be suppressed. If the average penetration depth of the porous film 22 into the pores 23 is less than the average film thickness of the porous film 22, cracks and peeling of the porous film 22 cannot be sufficiently suppressed.

As for the shape of the invading portion 22X of the porous membrane 22 into the pores 23 of the porous substrate 21, as shown in FIG. 3, a part of the porous membrane 22 is a pore along the inner wall 23a of the pore 23. The shape that penetrates in the depth direction of 23 can be mentioned. In this case, the porous film 22 is formed so as not only to close the portion opened to the upper surface 21a of the pore 23, but also to close the open portion of the pore 23 extending in various directions in the porous base material 21. Therefore, the absorbability of the gas to be separated by the porous membrane 22 and the separability based on the absorption can be improved. Further, as shown in FIG. 4, the shape of the invading portion 22X of the porous membrane 22 into the pores 23 is such that a part of the porous membrane 22 is present so as to block the inside of the pores 23. May be good. The portion 22Y that blocks the inside of the pores 23 of the porous membrane 22 doublely closes the pores 23 in addition to the porous membrane 22 that closes the upper surface open portion of the pores 23, so that the gas to be separated The absorbability of the substance and the separability based on the substance can be further enhanced. The shape of the portion 22Y that closes the inside of the pores 23 with the porous film 22 is not limited to the double structure shown in FIG. 4, and may be triple or more.

Regarding the amount of penetration of the porous membrane 22 into the pores 23, the fibrous inorganic material of the portion X invading the pores 23 with respect to the mass A of the fibrous inorganic material constituting the porous membrane 22 portion. It is preferable to set the ratio (B / A) of the mass B of the above to be more than 0.1 and less than 1. When the B / A ratio is 0.1 or less, not only the adhesion between the porous base material 21 and the porous membrane 22 is lowered, but also the gas separation rate is lowered. When the B / A ratio is 1 or more, the portion of the porous membrane 22 that does not contribute to gas separation increases, the gas separation performance decreases, and the gas permeation rate also decreases. The B / A ratio is preferably more than 0.2 and less than 0.5.

The average film thickness of the porous membrane 22 shall be measured as follows. Six points in the porous membrane 22 are randomly selected from the gas separator 5. An image obtained by observing a cross section of each selected point by a cross section SEM (Scanning Electron Microscope), a STEM (Scanning Transmission Electron Microscope), or a cross section TEM (Transmission Electron Microscope). A straight line is drawn in the film of the observation image in the film thickness direction, and the length at which the distance between the two points intersecting the upper surface and the lower surface of the film is the shortest is determined. The average value is calculated by finding the shortest distance between two points that intersect the upper surface and the lower surface at three or more points in one field of view. In each of the six selected visual fields, the average value of the shortest distance between the two points is obtained, and the average value of these values is taken as the average film thickness of the porous membrane 22.

The average penetration depth of the porous membrane 22 into the pores 23 shall be measured as follows. Six points in the porous membrane 22 are randomly selected from the gas separator 5. An observation image is obtained by observing the cross section of each selected point with a cross section SEM or a cross section TEM. In the observation image, it is specified how far the porous film 22 has penetrated in the depth direction of the porous base material 21, and the shortest distance between the tip of the invading portion and the surface of the porous base material 21 is obtained. For all the invading parts in the observation image, the shortest distance between the tip of the invading part and the surface of the base material is obtained, and the maximum value is selected. The distance (maximum value) of the tip of the penetrating portion is determined in each of the six selected visual fields, and the average value of these values is taken as the average penetrating depth of the porous membrane 22 into the pores 23. Further, for the B / A ratio, the cross-sectional area A'of the porous membrane 22 and the cross-sectional area B'of the invading portion 22X into the pore 23 are obtained from the observation image obtained by determining the penetration depth, and these ratios (cross-sectional area B) are obtained. It shall be obtained from'/ cross-sectional area A').

The constituent material of the porous base material 21 is not particularly limited, and can maintain the function as a support of the porous membrane 22 composed of the fibrous inorganic substance, and the gas to be treated containing the gas to be separated. It may be made of a material that does not obstruct the passage of gas. As the constituent material of the porous base material 23, ceramic materials such as oxide-based, nitride-based, oxynitride-based, and carbide-based materials, resin materials, carbon materials, metal materials, and the like are used. Specific examples of the porous base material 21 include porous ceramics, organic porous materials, carbon fiber molded products, synthetic fiber and natural fiber molded products (including paper), and non-woven fabrics. Specific constituent materials of the porous base material 21 include aluminum (Al), silicon (Si), zinc (Zn), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and titanium. A group consisting of oxides, nitrides, carbides, and silicates of (Ti), zirconium (Zr), nickel (Ni), cobalt (Co), iron (Fe), chromium (Cr), or copper (Cu). At least one compound selected from the above is mentioned, and these may form a mixture or a complex.

When porous ceramics are used as the porous base material 21, the constituent particles of the porous ceramics may be granular particles having a general spherical shape or a shape close to the general spherical shape, but plate-shaped particles are more preferable. .. The plate-shaped particles constituting the porous ceramics preferably have a shape having an aspect ratio of 2 or more in cross section, and more preferably have a shape having an aspect ratio of 4 or more in cross section. By using the porous ceramics composed of such plate-like particles as the porous base material 21, it is possible to facilitate the penetration of a part of the porous film 22 along the inner wall of the pores 23. Further, even when an aggregate or molded body of fibers is used as the porous base material 21, the fibers constituting the porous base material 21 preferably have a flat shape, and the aspect ratio of the cross section is 2 or more. The aspect ratio of the cross section is more preferably 4 or more.

Regarding the shape of the porous base material 21, the average pore diameter is 0.15 μm or more and 50 μm or less, and the volume porosity (volume fraction of the pores in the porous base material 21) is 20% or more and 70% or less. Is preferable. When the average pore diameter of the porous base material 21 is less than 0.15 μm, the passability of the gas to be treated including the gas to be separated tends to decrease. Further, if the average pore diameter of the porous base material 21 is too small, when the porous film 22 is formed on the porous base material 21, the inside of the pores 23 will be different depending on the average diameter and average length of the fibrous inorganic substance. The fibrous inorganic substance cannot sufficiently penetrate. From this point of view, the average pore diameter of the porous substrate 21 is more preferably 0.5 μm or more. Further, when the average pore diameter of the porous base material 21 exceeds 50 μm, the permeation amount of the gas to be treated becomes too large, and the gas separation performance by the porous membrane 22 tends to deteriorate. Further, if the average pore diameter of the porous base material 21 is too large, the formability of the porous membrane 22 on the porous base material 21 is lowered, and there is a possibility that the gas separation performance by the porous membrane 22 cannot be sufficiently obtained. From this point of view, the average pore diameter of the porous substrate 21 is more preferably 20 μm or less.

Further, when the volume porosity of the porous base material 21 is less than 20%, the amount of gas to be treated that can pass through the porous base material 21 decreases, and the amount of gas to be separated and the depressurization from the separation chamber 2 decrease. The amount of gas to be separated into the chamber 3 may be insufficient. Further, if the volume porosity of the porous base material 21 is too small, when the porous film 22 is formed on the porous base material 21, the fibrous inorganic substance cannot sufficiently penetrate into the pores 23. From this point of view, the volume porosity of the porous base material 21 is more preferably 30% or more. Further, if the volume porosity of the porous base material 21 exceeds 70%, the strength of the porous base material 21 may decrease, which may hinder the continuous operation of the gas separation device 1. Further, if the volume porosity of the porous base material 21 is too large, the formability of the porous membrane 22 on the porous base material 21 is lowered, and the gas separation performance by the porous membrane 22 cannot be sufficiently obtained. From this point of view, the volume porosity of the porous base material 21 is more preferably 60% or less. The volume porosity of the porous base material 21 and the shape of the pores 23 (average pore diameter) shall indicate values measured by the mercury intrusion method.

The thickness of the porous base material 21 is not particularly limited, but is preferably in the range of 30 μm or more and 3 mm or less. If the thickness of the porous base material 21 is too thin, deformation such as bending occurs during handling, and the porous membrane 22 may not only have defects such as cracks but also be damaged. Further, if the thickness of the porous base material 21 is too thick, the permeation rate of the gas to be separated such as the water vapor permeation rate becomes slow, and not only the gas separation performance is lowered, but also the thermal conductivity is lowered. Loss is likely to occur in heat exchange when separating the target gas from the processing gas. The overall shape of the porous base material 21 is not particularly limited, and various shapes such as a disk shape (cylindrical shape) and a rectangular parallelepiped shape can be applied depending on the configuration of the gas separation device 1.

The fibrous inorganic substance constituting the porous membrane 22 is preferably selected according to the gas to be separated. Examples of the gas to be separated include water vapor and organic solvent-based gas. Examples of the gas to be treated containing the gas to be separated include, but are not necessarily limited to, air containing the gas to be separated. Examples of the organic solvent-based gas include methanol, ethanol, n-propanol, i-propanol, n-butanol, i-butanol, s-butanol, t-butanol, ethyl acetate, n-ethyl acetate, i-butyl formate, and acetone. Examples thereof include vapors of methyl ethyl ketone, methyl isobutyl ketone, diethyl ether, diisopropanol, trichloroethylene, n-hexane and the like.

When the gas to be separated is water vapor, the fibrous inorganic substance constituting the porous membrane 22 is preferably a hydrophilic material. As constituent materials of the fibrous inorganic substance, aluminum (Al), silicon (Si), zinc (Zn), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), titanium (Ti), Oxides, nitrides, carbides, hydroxides, silicates, carbonates, of zirconium (Zr), nickel (Ni), cobalt (Co), iron (Fe), chromium (Cr), or copper (Cu), And at least one selected from the group consisting of phosphates.

Fibrous inorganic substances include oxides (including hydrates) such as Al, Si, Ti, Zr, Zn, Mg and Fe, hydroxides such as Al, Cu and Zn, Mg, Ca, Sr and the like. Compounds such as carbonates, phosphates such as Mg, Ca and Sr, or composites and mixtures thereof can be used. Further, it may be a metal compound in which the OH group is controlled by using a metal hydroxide as a precursor, binding the metal hydroxide by hydrolysis or the like, and stopping the reaction in the middle. Specific examples of the constituent materials of the fibrous inorganic substance include alumina (including hydrate), silica, titania, zirconia, magnesia, calcia, zinc oxide, ferrite, barium titanate and the like, and the fibrous inorganic substance. Specific examples of the above include hydroxide fibers of metals such as Al, Cu and Zn, oxide fibers such as alumina and silica, and metal fibers. It is more preferable that the fibrous inorganic substance further contains at least one selected from the group consisting of boehmite and pseudo-boehmite. Boehmite (AlOOH) and pseudo-boehmite, which are hydrates of alumina, have excellent affinity with water. Therefore, by forming the porous membrane 22 with boehmite or a fibrous substance of pseudo-boehmite, water vapor absorption and pseudo-boehmite can be achieved. Separability can be improved.

When the gas to be separated is an organic solvent gas, the fibrous inorganic substance includes composite material particles in which an additive element that disrupts the charge balance is introduced into the lattice of the above-mentioned hydrophilic compound particles, or the inside of the lattice of the hydrophilic compound particles. Defect-introducing material particles with atomic vacancies such as oxygen vacancies are used. The hydrophilic compounds are as described above, and examples of the additive elements introduced into the lattice of such compound particles include titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), and chromium (Cr). , Manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn) and the like. However, elements that overlap with the cationic elements that make up the compound particles are excluded. By introducing these elements into the lattice or introducing oxygen vacancies or the like into the lattice, affinity for organic solvents can be obtained.

Regarding the shape of the fibrous inorganic substance as described above, the average diameter d is preferably in the range of 1 nm or more and 10 nm or less, and the average length l is preferably 0.5 μm or more and 10 μm or less. In the porous film 22 made of such a fibrous inorganic substance, micropores are formed in the gaps between the fibrous inorganic substances. The average pore diameter of the porous membrane 22 is preferably 1 nm or more and 40 nm or less. By forming the porous membrane 22 with a fibrous inorganic substance having an average diameter d in the range of 1 to 10 nm, micropores having the average pore diameter as described above are formed in the porous membrane 22 in an appropriate amount. Can be done. The average diameter d of the fibrous inorganic substance is more preferably in the range of 2 nm or more and 10 nm or less.

According to the porous membrane 22 having micropores as described above, a liquefied substance of the gas to be separated, for example, water in the case of water vapor, or an organic solvent in the case of an organic solvent-based gas is retained in the micropores and is porous. A wet seal can be formed in the film 22. The gas to be separated from the gas to be separated in the separation chamber 2 is absorbed by the porous membrane 22 on which the wet seal is formed, and the gas to be separated in the porous membrane 22 becomes the pressure difference between the separation chamber 2 and the decompression chamber 3. The gas to be separated can be separated from the gas to be treated by discharging the gas into the decompression chamber 3 based on the above. The gas separator 5 having the porous membrane 22 may contain a liquefied substance of the gas to be separated from the beginning, or may contain the liquefied substance when the gas separator 5 is used.

Although it depends on the average pore diameter and volume porosity of the porous substrate 21, the porous film 22 is formed by forming the porous film 22 using a fibrous inorganic substance having an average length l of 0.5 to 10 μm. Can be satisfactorily penetrated into the pores of the porous base material 21. If the average length l of the fibrous inorganic substance exceeds 10 μm, the fibrous inorganic substance cannot sufficiently penetrate into the pores. Further, when the average length l of the fibrous inorganic substance is less than 0.5 μm, the formability of the porous membrane 22 is lowered, and the function as the gas separator 5 is lowered. It is more preferable that the average length l of the fibrous inorganic substance is 1 μm or more and 3 μm or less. The average length l of the fibrous inorganic substance is preferably set in consideration of the average pore diameter of the porous base material 21. That is, it is preferable to set the average length l of the fibrous inorganic substance so that the average pore diameter of the porous base material 21 is 2 times or more and 30 times or less the average length l of the fibrous inorganic substance. It is more preferable that the average pore diameter of the porous base material 21 is 3 times or more and 10 times or less the average length l of the fibrous inorganic substance.

Further, by setting the average pore diameter of the porous membrane 22 to 1 nm or more and 40 nm or less, it becomes easy to hold the liquefied product of the gas to be separated in the fine pores which are the paths of the gas to be separated, and the porous membrane 22 is wet. A seal can be easily formed, and an appropriate permeation flow rate of the gas to be separated can be secured. When the average pore diameter of the porous membrane 22 is less than 1 nm, the permeation flow rate of the gas to be separated tends to decrease. Further, when the average pore diameter of the porous membrane 22 exceeds 40 nm, the formability of the wet seal is lowered, and the balance between the absorption of the gas to be separated from the inside of the separation chamber 2 and the release of the gas to be separated into the decompression chamber 3 is achieved. Is reduced, and the gas separation performance is likely to be lowered. The average pore diameter of the porous membrane 22 is more preferably 2 nm or more and 10 nm or less.

The porous film 22 composed of the fibrous inorganic substance as described above preferably has an average film thickness of 0.5 μm or more and 50 μm or less. By forming a wet seal on the porous film 22 having such an average film thickness, good gas separation performance can be obtained. If the average film thickness of the porous film 22 is less than 0.5 μm, the amount of wet seal formed or the like may be insufficient, and sufficient gas separation performance may not be obtained. Further, when the average film thickness of the porous membrane 22 exceeds 50 μm, the permeation flow rate of the gas to be separated tends to decrease. The average film thickness of the porous membrane 22 is more preferably 5 μm or more and 25 μm or less.

The average pore diameter of the porous membrane 22 can be evaluated by the BJH (Barrett, Joiner, Hallender) method of the physical gas adsorption method. Further, since the average diameter of the fibrous substance in the porous sedimentary layer of the fibrous substance is 2 to 4 times the average pore diameter, the average diameter of the fibrous inorganic substance can be obtained as a conversion value from the average pore diameter. .. The fact that the porous membrane 22 is composed of the fibrous inorganic substance can be confirmed by bending and breaking the gas separator 5 having the porous membrane 22 and observing the fibrous structure of the fracture surface. When the easily bendable porous base material 21 is used, the porous membrane 22 is torn by bending it greatly. Therefore, by observing the membrane surface of such a porous membrane 22 by SEM, it is confirmed that the porous membrane 22 has a fibrous structure. can do. Further, as for the composition of the porous membrane 22, the crystal structure can be specified by analyzing the membrane surface with XRD, so that the constituent material of the porous membrane 22 can be specified.

The gas separator 5 made of the porous base material 21 having the porous membrane 22 described above is 1 × 10 ^-16 m ² or more based on the fine pores in the porous membrane 22 and the pores in the porous membrane 22. It is preferable to have an air permeability K of 1 × 10 ^-10 m ^{2 or less.} By using the gas separator 5 having such an air permeability, the gas to be separated contained in the gas to be treated in the separation chamber 2 can be satisfactorily removed through the wet seal formed in the porous membrane 22. It can be moved into the decompression chamber 3. If the air transmittance K of the composite member 21 ^{is less than 1 × 10 -16} m ² , the permeation rate of the gas to be separated decreases. If the air transmittance K exceeds 1 × 10 ^-12 m ² , air leakage occurs, the wet sealability is lowered, and the separation rate α or the like of the gas to be separated is likely to be lowered. The air permeability K of the gas separator 5 is more preferably ^{1 × 10-14} m ² or more and 1 × 10 ^-12 m ^{2 or less.}

_{Here, the air transmittance K is derived from the pressure difference ΔP [unit: kPa] and the flow velocity Qair} [unit: cm ³ / min] of the inflow and outflow at that time when a constant volume of air is passed in the vertical direction of the sample. , Obtained based on the following equation (1). (1) In the equation, [delta] is the thickness of the sample, A is the area of the sample, the mu _air is air viscosity (18.57μPa · s).
K = (Q _air / ΔP) ・ (μ _air / A) ・ δ… (1)

When the gas separator 5 is used as the steam separator, the steam separator (5) may include a water-soluble hygroscopic agent existing in the micropores of the porous membrane 22. Since the water-soluble hygroscopic agent absorbs and retains water, it becomes easy to form a wet seal in the porous membrane 22. As the water-soluble hygroscopic agent, citrates, carbonates, phosphates, halide salts, oxide salts, hydroxide salts, sulfates and the like of Group 1 and Group 2 elements are used. These compounds may be used alone or in combination. The water-soluble hygroscopic agent may be segregated and present in the micropores, or may be thinly and uniformly adhered to the entire or part of the inner wall of the micropores. The water vapor separator (5) may include a gas-adsorbed liquid such as an ionic liquid existing in the micropores of the porous membrane 22.

Specific examples of the water-soluble hygroscopic agent include calcium chloride (CaCl ₂ ), lithium chloride (LiCl), sodium chloride (NaCl), potassium chloride (KCl), lithium bromide (LiBr), sodium bromide (NaBr), and odor. Potassium oxide (KBr), lithium iodide (LiI), sodium iodide (NaI), potassium iodide (KI), calcium oxide (CaO), sodium oxide (Na ₂ O), potassium oxide (K ₂ O), water Calcium oxide (Ca (OH) ₂ ), sodium hydroxide (NaOH), potassium hydroxide (KOH), lithium hydroxide (LiOH), calcium carbonate (CaCO ₃ ), magnesium carbonate (MgCO ₃ ), lithium carbonate (Li ₂₎ CO ₃ ), sodium carbonate (Na ₂ CO ₃ ), potassium carbonate (K ₂ CO ₃ ), sodium phosphate (Na ₃ PO ₄ ), potassium phosphate (K ₃ PO ₄ ), sodium citrate (Na ₃ (C)) ₃ H ₅ O (COO) ₃ ), etc.), potassium citrate (K ₃ (C ₃ H ₅ O (COO) ₃ ), etc.), sodium sulfate (Na ₂ SO ₄ ), potassium sulfate (K ₂ SO ₄ ), Examples thereof include lithium sulfate (Li ₂ SO ₄ ) and hydrates thereof.

As shown in FIG. 5, the gas separator 5 used in the gas separator 1 may be supported by a support 31 that allows gas to pass through. FIG. 5 shows a state in which the pair of supports 31 are arranged along both surfaces of the gas separator 5, but the support 31 may be arranged along only one surface of the gas separator 5. For the support 31, for example, paper, punching metal, polyimide porous body or the like is used, and a mesh-like substance other than these may be used. The support 31 preferably has a through hole having a diameter of several μm or more, but is not limited to this.

The gas to be treated, such as air containing the gas to be separated, is sent into the separation chamber 2 by operating the blower 6 as described above. By operating the decompression pump 7 at the same time as the blower 6 to depressurize the inside of the decompression chamber 3, a difference is generated between the pressure in the separation chamber 2 and the pressure in the decompression chamber 3. Due to this pressure difference, the partial pressure of the gas to be separated such as the water vapor pressure in the decompression chamber 3 (the partial pressure of the gas to be separated in the second space S2 (hereinafter, also simply referred to as gas partial pressure)) is in the separation chamber 2. It is smaller than the partial pressure of gas such as water vapor pressure (partial pressure of gas in the first space S1). Since the gas separator 5 forms a wet seal with the liquefied gas to be separated held in the micropores of the porous membrane 22, a gas partial pressure difference is generated between the separation chamber 2 and the decompression chamber 3. By generating the gas, the gas to be separated occurs between the separation chamber 2 and the decompression chamber 3 arranged via the gas separator 5.

In causing the gas to be separated to move through the gas separator 5, the decompression pump 7 is used to move the decompression chamber 3 so that the pressure in the decompression chamber 3 is -50 kPa or less with respect to the pressure in the separation chamber 2. It is preferable to reduce the pressure. In other words, it is preferable to reduce the pressure in the pressure reducing chamber 3 so that the difference between the pressure in the separation chamber 2 and the pressure in the pressure reducing chamber 3 is 50 kPa or more. If this pressure difference is less than 50 kPa, the movement of the gas to be separated from the separation chamber 2 to the decompression chamber 3 may not be sufficiently promoted. Further, the pressure difference between the separation chamber 2 and the decompression chamber 3 is preferably less than 100 kPa. If the pressure difference is too large, the porous base material 21 and the porous membrane 22 constituting the gas separator 5 may be damaged. The pressure difference between the separation chamber 2 and the decompression chamber 3 is more preferably in the range of 80 to 90 kPa. However, this is not always the case because it depends on the vapor pressure of the gas to be separated.

In the gas separation device 1 shown in FIG. 1, a decompression pump 7 that decompresses the inside of the decompression chamber 3 causes a gas partial pressure difference between the separation chamber 2 and the decompression chamber 3. It is not limited to this. For example, dry air or heated air may be introduced into the decompression chamber 3 (second space S2). This also makes it possible to generate a gas partial pressure difference such as a water vapor pressure difference between the separation chamber 2 and the decompression chamber 3. In the gas separation device 1 shown in FIG. 1, the gas pressure adjusting unit that causes a gas partial pressure difference between the separation chamber 2 and the decompression chamber 3 is not particularly limited, and a gas partial pressure difference can be generated. Various mechanisms can be applied.

The gas to be separated contained in the gas to be treated in the separation chamber 2 having a relatively high gas partial pressure is contained in a wet seal formed in the gas separator 5, specifically, in the fine pores of the porous film 22. It is absorbed by the retained liquefied gas to be separated. The liquefied gas to be separated in the gas separator 5 permeates into the decompression chamber 3 having a relatively low gas partial pressure. Depending on the balance between the gas partial pressure in the separation chamber 2, the gas partial pressure in the decompression chamber 3, and the amount of liquefied gas to be separated in the gas separator 5, the gas to be separated contained in the gas to be treated in the separation chamber 2 Absorption by the gas separator 5 and release of the gas to be separated into the decompression chamber 3 in the gas separator 5 occur continuously.

The absorption of the gas to be separated by the gas separator 5 and the release of the gas to be separated into the decompression chamber 3 in the gas separator 5 occur continuously in the separation chamber 2 (first space S1). The concentration of the gas to be separated, and further, the concentration of the gas to be separated in the space to be treated connected to the separation chamber 2 via the blower 6 can be continuously reduced. When the gas to be separated is water vapor, the amount of water vapor in the separation chamber 2 and the space to be treated can be reduced to dehumidify. The gas to be treated, such as air having a reduced gas concentration, is returned from the separation chamber 2 to the space to be treated. The gas to be separated such as water vapor that has permeated into the decompression chamber 3 is discharged to the outside through the pipe 11, the decompression pump 7, and the pipe 14. When the gas to be separated is water vapor, the moisture permeated into the decompression chamber 3 may be sent to a third space such as a room requiring humidification. When the gas to be separated is an organic solvent gas, the organic solvent and its gas are recovered as needed.

In the gas separation device 1 of the embodiment, since the gas separator 5 forms a wet seal, only the gas to be separated contained in the gas to be treated such as air in the separation chamber 2 is moved into the decompression chamber 3. Can be made to. For example, when the gas separation device 1 is used as a dehumidifying device, basically only the moisture in the air moves between the separation chamber 2 and the decompression chamber 3, and the dry air in the air hardly moves. Therefore, the temperature of the space to be dehumidified is hardly changed. By dehumidifying the space with almost no fluctuation in the temperature of the space to be treated, there is no risk of reducing the thermal efficiency even when used in combination with cooling the space, for example. The thermal efficiency when the dehumidifier is used in combination with the air conditioner can be improved.

The gas separator 5 shown in FIGS. 2 to 4 is formed on the surface of the porous base material 21 and at least one of the porous base material 21 as described above, is composed of a deposited layer of the fibrous inorganic material, and is formed between the fibrous inorganic materials. It is provided with a porous film 22 having fine pores. The gas separator 5 has an air permeability ^{of 1 × 10 -16} m ² or more and 1 × 10 ^-12 m ^{2 or less.} By using such a gas separator 5, the gas to be separated contained in the gas to be treated in the separation chamber 2 is satisfactorily and practically permeated through the wet seal formed in the gas separator 5. It can be moved into the decompression chamber 3 at a speed. That is, it is possible to improve the permeation rate V of the gas to be separated while maintaining a practical separation rate α of the gas to be separated, for example, a separation rate α of about 3 to 100. As a result, it is possible to provide a gas separator 5 having performance, strength, reliability and the like practically applicable to air conditioning and the like, and a gas separator 1 using the gas separator 5 which does not require a regeneration process.

The gas separation rate α is the ratio of the permeation amount of the liquefied gas such as water and the dry air constituting the gas to be treated, and is defined by the following equation (2).
α = (N4 _liquid / N4 _air ) / (N3 _liquid / N3 _air )… (2)
In the formula (2), (N3 _liquid / N3 _air ) is the molar ratio of the liquefied gas contained in the gas to be treated (air) supplied to the separation chamber 2 (first space S1) and the dry air, (N4 _liquid). / N4 _air ) is the molar ratio of the liquefied gas contained in the gas to be treated (air) discharged from the decompression chamber 3 (second space S2) to the dry air. When α is 1, it means that a liquefied gas (water or the like) and dry air flow from the separation side space S1 to the decompression side space S2 at the same ratio. When α is 100, it means that the permeation of dry air is reduced to 1/100 of the permeation of the liquefied gas (water or the like) from the dehumidifying side space S1 to the decompression side space S2.

The permeation velocity V of the gas (liquefied product) is defined by the following equation (3).
V = ΔM _liquid / A / Δt… (3)
In the formula (3), ΔM _liquid is the amount of gas liquefied recovered in the decompression side space S2, A is the area of the gas separator 5, and Δt is the time.

(Second Embodiment)
Next, a configuration example using the gas separation device 1 according to the first embodiment as a dehumidifying device will be described with reference to FIGS. 6 and 7. In FIG. 6, R indicates a room constituting the target space Rx for dehumidification, and the room R has an intake port Ra. The dehumidifying device 1 is provided in the room R in order to remove water vapor (moisture) from the air in the space Rx to be dehumidified. The dehumidifying device 1 shown in FIG. 6 has a structure in which a pipe 15 for taking in external air is connected to a decompression chamber 3 (second space S2). In the dehumidifying device 1, the pressure inside the pressure reducing chamber 3 is reduced while taking in outside air into the pressure reducing chamber 3. The pipe 15 has a valve 16. The pipe 15 may be omitted.

The air in the space Rx is basically composed of water vapor (moisture) and dry air. By operating the blower 6, the air in the space Rx is sent into the separation chamber (dehumidification chamber) 2 of the dehumidifier 1 through the pipes 12 and 10. The dehumidified air in the separation chamber 2 is returned to the space Rx via the pipe 13. The dehumidifying operation (gas separation operation) using the gas separator 5 is as described in detail in the first embodiment. That is, moisture permeates from the separation chamber 2 to the decompression chamber 3 through the gas separator 5 on which the wet seal is formed. Since the absorption of the moisture in the air in the separation chamber 2 by the gas separator 5 and the release of the moisture in the gas separator 5 to the decompression chamber 3 occur continuously, the continuous dehumidification without the regeneration treatment is performed. Dehumidifying performance such as dehumidifying speed can be improved. Therefore, it is possible to provide a practical and efficient dehumidifying device 1.

The applicable structure of the dehumidifying device 1 of the embodiment is not limited to the structure shown in FIG. The dehumidifying device 1 of the embodiment can be variously modified. In FIG. 6, the first space S1 is set in the separation chamber 2 of the dehumidifying device 1, but the first space S1 is not limited to this. As shown in FIG. 7, the first space S1 may be the target space Rx itself for dehumidification. That is, the decompression chamber 3 serving as the second space S2 may be arranged via the target space Rx serving as the first space S1 and the gas separator 5. In this case, by depressurizing the pressure reducing chamber 3, water vapor (moisture) is directly removed from the air in the dehumidifying target space Rx (first space S1). The settings of the first space S1 and the second space S2 can be changed in various ways.

The dehumidification rate V indicates a value measured as follows. First, a space Rx is provided in a constant temperature and humidity chamber in which humidity and temperature are kept constant by a 1-liter container having a hole with a diameter of 10 mm. In such a structure, the dehumidifying device (gas separating device) shown in FIG. 1 sets the pressure of the second space with respect to the first space to -80 kPa to perform dehumidification, and dehumidifies the humidity by 10% from a specific relative humidity. The time when dehumidifying to a low relative humidity is defined as the area-converted value of the steam separator (gas separator). The measurement temperature is 40 ° C., and the execution area of the steam separator is a circle with a diameter of 10 mm (area: 78.54 mm ² ). For example, if the time when the relative humidity drops from 70% to 60% is 1 hour, the dehumidification rate V is 10% / h.

Next, examples and their evaluation results will be described.

(Example 1)
First, as a porous substrate, a disk-shaped alumina ceramic porous body having an average pore diameter of 3.4 μm, a volume porosity of 40%, a thickness of 1 mm, and a diameter of 20 mm was prepared. A fibrous boehmite dispersion (alumina sol liquid F1000 (average diameter d = 4 nm, average length l = 1.4 μm), manufactured by Kawaken Fine Chemicals Co., Ltd.) is applied to one surface of this alumina ceramic porous body using a slide glass. A gas separator was prepared by applying by the cast method, drying at 40 ° C., and then heat-treating at 200 ° C. to form a porous membrane made of a fibrous inorganic substance containing boehmite.

The shape and characteristics of the gas separator made of the above-mentioned porous body made of alumina ceramics having a porous film were measured and evaluated as follows. First, when the air permeability of the gas separator was measured by the method described above, the air permeability K was 5 × 10 ^-13 m ² . Moreover, when the porous membrane was evaluated by the XRD method, a boehmite phase was confirmed. When the average film thickness and the average pore diameter of the porous film were measured according to the method described above, the average film thickness was 17 μm and the average pore diameter was 1.4 nm. The average diameter of the fibrous inorganic substance converted from the average pore diameter was about 4.2 nm, which was almost the same as the fiber diameter (average diameter d) in the raw material dispersion. Further, in the cross-sectional TEM observation of the porous film, it was confirmed that a part of the porous film made of the fibrous inorganic substance penetrated into the pores of the porous body made of alumina ceramics as the base material. When the average penetration depth into the pores of the porous film and the ratio (B / A) of the mass B of the penetration portion to the film mass A were measured according to the method described above, the average penetration depth was 20 μm and the mass ratio B. / A was 0.5.

When the water vapor separation rate α and the water vapor permeation rate V were measured using the above-mentioned gas separator as the water vapor separator, the water vapor separation rate α> under the conditions that the temperature of the supply air to the dehumidifying side was 40 ° C. and saturated steam. It was 100 (above the measurement limit, the same applies hereinafter), and the water vapor permeation rate V = 590 g / h / m ² . In addition, the gas separator was used as a steam separator to dehumidify a 1-liter container. When the inside of the container was dehumidified and dehumidified through the separator for 1 hour, the relative humidity was 90%, the humidity before dehumidification was reduced to 30%, and the dehumidification rate was 60% / h. Furthermore, when the dehumidification test was repeated several times, similar results were obtained in each case.

(Example 2)
The same porous body made of alumina ceramics as in Example 1 is dip-coated with the same fibrous boehmite dispersion liquid (alumina sol liquid F1000) as in Example 1, dried at 40 ° C, and then heat-treated at 200 ° C. A porous film made of a fibrous inorganic substance containing boehmite was formed. The fibrous boehmite dispersion was repeatedly dip and dried three times.

The shape and characteristics of the gas separator made of the above-mentioned porous body made of alumina ceramics having a porous film were measured and evaluated in the same manner as in Example 1. As a result, the air transmittance K was 8 × 10 ^-13 m ² , and the boehmite phase was confirmed from the evaluation of the porous membrane by the XRD method. The average film thickness of the porous membrane was 7 μm, and the average pore diameter was 1.4 nm. Further, in the cross-sectional TEM observation of the porous film, it was confirmed that a part of the porous film made of the fibrous inorganic substance penetrated into the pores of the porous body made of alumina ceramics as the base material. Further, as shown in FIG. 4, it was confirmed that a part of the porous film invading the pores was present so as to block the inside of the pores. The average penetration depth of the porous membrane into the pores was 20 μm, and the ratio (B / A) of the mass B of the invading portion to the membrane mass A was 0.7.

When the water vapor separation rate α and the water vapor permeation rate V were measured using the above-mentioned gas separator as the water vapor separator, the water vapor separation rate α> under the conditions that the temperature of the supply air to the dehumidifying side was 40 ° C. and saturated steam. 100, the water vapor permeation rate V = 720 g / h / m ² . In addition, the gas separator was used as a steam separator to dehumidify a 1-liter container. When the inside of the container was dehumidified and dehumidified through the separator for 1 hour, the relative humidity was 90%, the humidity before dehumidification was reduced to 30%, and the dehumidification rate was 60% / h. Furthermore, when the dehumidification test was repeated several times, similar results were obtained in each case.

(Example 3)
The same porous body made of alumina ceramics as in Example 1 is spray-coated with the same fibrous boehmite dispersion liquid (alumina sol liquid F1000) as in Example 1, dried at 40 ° C, and then heat-treated at 200 ° C. A porous film made of a fibrous inorganic substance containing boehmite was formed. The fibrous boehmite dispersion was sprayed and dried three times.

The shape and characteristics of the gas separator made of the above-mentioned porous body made of alumina ceramics having a porous film were measured and evaluated in the same manner as in Example 1. As a result, the air transmittance K was 9 × 10 ^-13 m ² , and the boehmite phase was confirmed from the evaluation of the porous membrane by the XRD method. The average film thickness of the porous membrane was 3 μm, and the average pore diameter was 1.4 nm. Further, in the cross-sectional TEM observation of the porous film, it was confirmed that a part of the porous film made of the fibrous inorganic substance penetrated into the pores of the porous body made of alumina ceramics as the base material. The average penetration depth of the porous membrane into the pores was 30 μm, and the ratio (B / A) of the mass B of the invading portion to the membrane mass A was 0.9.

When the water vapor separation rate α and the water vapor permeation rate V were measured using the above-mentioned gas separator as the water vapor separator, the water vapor separation rate α> under the conditions that the temperature of the supply air to the dehumidifying side was 40 ° C. and saturated steam. 100, the water vapor permeation rate V = 770 g / h / m ² . In addition, the gas separator was used as a steam separator to dehumidify a 1-liter container. When the inside of the container was dehumidified and dehumidified through the separator for 1 hour, the relative humidity was 90%, the humidity before dehumidification was reduced to 20%, and the dehumidification rate was 70% / h. Furthermore, when the dehumidification test was repeated several times, similar results were obtained in each case.

(Example 4)
Using the gas separator prepared in the same manner as in Example 1, an experiment for separating IPA from a mixed solution of isopropyl alcohol (IPA) and water was carried out. As the mixed solution, a mixture of IPA: water = 10:90 (mass%), that is, a 10% aqueous solution of IPA was used, this was vaporized and filled in a closed container, and the gas separator shown in FIG. 1 was used. Gas separation was performed by reducing the pressure to 90 kPa. The experiment was carried out in a constant temperature bath at 40 ° C. The gas that permeated the gas separation membrane was cooled with a refrigerant of acetone / dry ice, liquefied, and the concentration was measured. As a result, it was confirmed that the gas was an 80% IPA solution. Furthermore, when the above gas separation test was repeated several times, similar results were obtained in each case.

(Comparative Example 1)
As the porous substrate, an alumina ceramic porous body having an average pore diameter of 0.1 μm, a volume porosity of 40%, a thickness of 1 mm, and a diameter of 20 mm was prepared. The same fibrous boehmite dispersion liquid (alumina sol liquid F1000) as in Example 1 was applied to one surface of the alumina ceramic porous body by a casting method using a slide glass, dried at 40 ° C., and then 200. By heat treatment at ° C., a porous film made of a fibrous inorganic substance was formed.

A gas separator made of an alumina ceramic porous body having the above-mentioned porous film was used as a steam separator to dehumidify a 1-liter container. When the inside of the container was dehumidified and dehumidified through the separator for 1 hour, the relative humidity was 90%, the humidity before dehumidification was reduced to 50%, and the dehumidification rate was 40% / h. Moreover, when the dehumidification test was performed again, the dehumidification performance was not obtained this time. When the surface of the gas separator was observed with the naked eye, peeling of the porous membrane was observed. The average film thickness of the porous membrane was 17 μm. In the cross-sectional TEM observation of the porous membrane, a part of the porous membrane made of a fibrous inorganic substance penetrated into the pores of the porous body made of alumina ceramics as a base material, but inside the pores of the porous membrane. The average depth of penetration into the membrane was 5 μm.

(Comparative Example 2)
As the porous substrate, an alumina ceramic porous body having an average pore diameter of 60 μm, a volume porosity of 40%, a thickness of 1 mm, and a diameter of 20 mm was prepared. The same fibrous boehmite dispersion liquid (alumina sol liquid F1000) as in Example 1 was applied to one surface of the alumina ceramic porous body by a casting method using a slide glass, dried at 40 ° C., and then 200. By heat treatment at ° C., a porous film made of a fibrous inorganic substance was formed.

A gas separator made of an alumina ceramic porous body having the above-mentioned porous film was used as a steam separator to dehumidify a 1-liter container. When the inside of the container was depressurized and dehumidified through the separator for 1 hour, no dehumidifying performance was obtained. When the surface of the gas separator was observed with the naked eye, the porous film was not uniformly formed, and dents like pores were observed in some places. Moreover, when the porous membrane was observed by SEM, the membrane structure that closed the pores of the porous body as shown in FIGS. 3 and 4 was not observed.

Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other embodiments, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are also included in the scope of the invention described in the claims and the equivalent scope thereof.

1 ... Gas separator, 2 ... Dehumidifying chamber, 3 ... Decompression chamber, 4 ... Connection path, 5 ... Gas separator, 6 ... Blower, 7 ... Decompression pump, 21 ... Porous substrate, 22 ... Porous membrane, 23 ... pores, S1 ... first space, S2 ... second space.

Claims (12)

A porous substrate having a first surface, a second surface facing the first surface, and pores leading from the first surface to the second surface.
A porous film provided on at least one of the first surface and the second surface of the porous substrate so as to close at least a part of the pores and containing a fibrous inorganic substance is provided.
A part of the porous membrane penetrates along the inner wall of the pores of the porous substrate, and the average penetration depth of the porous membrane into the pores is the average thickness of the porous membrane. Ri der above,
The porous substrate comprises aluminum, silicon, zinc, magnesium, calcium, strontium, barium, titanium, zirconium, nickel, cobalt, iron, chromium, or copper oxides, nitrides, carbides, and silicates. It is a porous ceramic containing at least one selected from the group.
The fibrous inorganic substances include oxides, nitrides, carbides, and water containing hydrates of aluminum, silicon, zinc, magnesium, calcium, strontium, barium, titanium, zirconium, nickel, cobalt, iron, chromium, or copper. A gas separator comprising at least one selected from the group consisting of oxides, silicates, carbonates, and phosphates. The gas separator according to claim 1, wherein the fibrous inorganic substance has an average diameter of 1 nm or more and 10 nm or less. The gas separator according to claim 1 or 2, wherein the average pore diameter of the porous membrane is 1 nm or more and 40 nm or less. The gas separator according to any one of claims 1 to 3, wherein the average film thickness of the porous membrane is 0.5 μm or more and 50 μm or less. The fibrous inorganic material, seen at least Tsuo含selected from the group consisting of boehmite and pseudo-boehmite, the porous ceramics including alumina, gas according to any one of claims 1 to 4 Isolate. The gas separator according to any one of claims 1 to 5 , wherein the average pore diameter of the porous substrate is 0.15 μm or more and 50 μm or less. The gas separator according to any one of claims 1 to 6 , wherein the porous substrate has a volume porosity of 20% or more and 70% or less. The gas separator according to any one of claims 1 to 7 , wherein the air permeability is 1 × 10 ^-16 m ² or more and 1 × 10 ^-10 m ^{2 or less.} By being arranged between the first space and the second space, the partial pressure of the gas to be separated in the second space is made lower than the partial pressure of the gas to be separated in the first space. The gas separator according to any one of claims 1 to 8 , which is used as a gas separator for permeating the separation target gas existing in the first space into the second space. The first space and
The second space leading to the first space and
The gas separator according to any one of claims 1 to 8 , which is provided so as to partition between the first space and the second space.
A gas pressure that adjusts the partial pressure of the gas to be separated in the second space so that the partial pressure of the gas to be separated in the second space is lower than the partial pressure of the gas to be separated in the first space. Equipped with an adjustment unit
A gas separation device for permeating the gas to be separated existing in the first space into the second space through the gas separator. The gas separation device according to claim 10 , wherein the gas pressure adjusting unit includes a pressure adjusting mechanism for reducing the pressure in the second space from the pressure in the first space. The gas separation apparatus according to claim 10 or 11 , wherein the gas to be separated is water vapor, and the water vapor existing in the first space is permeated into the second space through the gas separator. ..

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