JP2019042654A - Gas separation body and gas separator - Google Patents

Abstract

To provide a gas separation body capable of obtaining performance, strength, reliability and the like applicable to air conditioning and the like while keeping practical gas separation performance and to provide a gas separator using the same.SOLUTION: In a gas separation body 5 of an embodiment including a porous base material 21 having a pore 23 communicating from a first face 21a to a second face 21b and a porous film 22 containing a fibrous inorganic material disposed so as to close at least a part of the pore 23 on at least one of the first face 21a and the second face 21b of the porous body 21, a part of the porous film 22 is immersed into the pore 23 along the inside wall of the pore 23 in the porous base material 21, and an average entry depth of the porous film 22 to the pore 23 is equal to the average film thickness of the porous film 22 or higher.SELECTED DRAWING: Figure 3

Description

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

  In air conditioning technology such as home air conditioners, technology has progressed in both refrigerant and energy efficiency, and a more comfortable living environment is required accordingly. For this reason, not only temperature, but also multifunctionalization of air conditioners such as humidity control, ventilation, air flow control, air purification, etc. is progressing. Improvement of energy efficiency is the most important issue from the recent energy shortage. Even in Asian countries with high temperature and high humidity, with the improvement of living standard, humidity control, especially dehumidification is considered to be important, and air conditioning with a small environmental load is required by performing this with energy saving. Dehumidification by refrigerant cooling using a compressor or the like, which is currently mainstream, requires a great deal of energy because it cools air to condense water vapor and reheats the cooled air to adjust its temperature. For this reason, since power consumption increases, the size of the environmental load is an issue.

  Gas separation devices such as desiccant air conditioning have better energy saving performance than refrigerant-type dehumidification because they absorb indoor moisture with a hygroscopic device using a hygroscopic material that adsorbs water vapor and warm it up and discharge it outdoors. . As a hygroscopic material, for example, a porous material such as a ceramic porous body or zeolite impregnated with a deliquescent substance consisting of chloride or bromide such as sodium, lithium, calcium, magnesium or the like is known. However, since the hygroscopic material is saturated by continuing to adsorb water, regeneration treatment is required. The regeneration treatment of the hygroscopic material is performed by heating the hygroscopic material and discharging water. It is inefficient to use the hygroscopic material regeneration process in combination with cooling.

  On the other hand, in order to dehumidify the air used for instrumentation equipment etc., the dehumidifying apparatus using a hygroscopic film like a zeolite film is known. A dehumidifying device using a zeolite membrane is excellent in moisture absorption performance of water vapor, but has a problem that the flow rate and transmission rate of water vapor are small. In air conditioning applications and the like, it is necessary to secure the flow rate and flow rate, so a dehumidifying device using a zeolite membrane can not constitute a practical air conditioning device. In the case of using zeolite as a hygroscopic material, it has been studied to use a powder compact other than the membrane. However, the molded body using a binder can not obtain the inherent hygroscopic performance of zeolite because the particle surface is covered with the binder. A green compact obtained by compressing and solidifying zeolite powder has excellent initial performance, but on the other hand, deterioration with time is remarkable, and it is impossible to construct a practical air conditioner like the zeolite membrane.

  As an energy-saving and low-cost alternative to the current air-conditioning system, a continuous dehumidification system using a steam separator that does not require regeneration is being considered. As a structure of a humidity control apparatus using a steam separator, a gas separator in which a liquid absorbent such as an aqueous solution of lithium chloride is filled between two water vapor permeable membranes using polyethylene, fluorine resin, etc. is conditioned. There is a structure disposed between a space such as an indoor space and a space such as an outdoor space, and the exchange of water vapor is performed between the indoor air and the liquid absorbent through a water vapor permeable membrane. However, the water vapor permeable membrane is easily broken, and further, in this method, it is difficult to dehumidify efficiently because the moving speed of water vapor is low.

  Also, for example, as an inorganic separation membrane that separates water from an aqueous alcohol solution or separates different types of gas from a mixture of water vapor and different types of gas, on one side of a support made of a porous material, There has been proposed 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. 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 piled fibrous alumina particles are It is used to obtain the separation performance of liquid and gas. However, in the structure in which fibrous alumina particles are simply stacked on a porous support, cracks occur in the arrangement direction of the fibrous alumina particles when used in the porous thin film layer composed of fibrous alumina particles, and from the support There is a risk of peeling off gradually. For this reason, there is a problem that separation performance can not be obtained continuously.

JP, 2016-176674, A Unexamined-Japanese-Patent No. 2003-336863 Patent No. 5621965 gazette JP, 2016-123893, A

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

  A gas separator according to an embodiment is a porous substrate having a first surface, a second surface facing the first surface, and pores communicating with the first surface to the second surface. And at least one of the first surface and the second surface of the porous substrate, the porous film comprising a fibrous inorganic material, which is provided to close at least a part of the pores. A portion 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 to the pores is the average of the porous membrane It is more than the film thickness.

  A gas separation apparatus according to an embodiment is provided to divide a first space, a second space communicating with the first space, and the first space and the second space. The gas to be separated in the second space such that the partial pressure of the gas to be separated in the second space and 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 And a gas pressure adjusting unit for adjusting the partial pressure of the gas separation device, and is configured to allow the gas to be separated present in the first space to pass through the gas separator to the second space.

It is a figure showing composition of a gas separation device of an embodiment. It is sectional drawing which shows the schematic structure of the gas separator of the gas separation apparatus shown in FIG. It is a fragmentary sectional view which shows typically an example of the fine structure of the gas separator shown in FIG. It is a fragmentary sectional view which shows typically the other example of the fine structure of the gas separator shown in FIG. It is sectional drawing which shows the usage 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 dehumidifier. It is a figure which shows the 2nd example which used the gas separation apparatus shown in FIG. 1 as a dehumidifier.

  Hereinafter, a gas separator according to an embodiment and a gas separator using the same will be described with reference to the drawings. In each of the embodiments, substantially the same components are denoted 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 planar dimension, the ratio of the thickness of each part, etc. may be different from the actual one. The term indicating the direction such as top and bottom in the description may be different from the actual direction based on the direction of gravitational acceleration.

First Embodiment
FIG. 1 shows the configuration of a gas separation apparatus according to an embodiment. The gas separation apparatus 1 shown in FIG. 1 is an object to be treated such as air containing a gas (separation target gas) such as water vapor or an organic solvent-based gas (organic solvent vapor) existing in a space to be treated (a treatment target space). It is an apparatus for separating the gas to be separated from the processing gas and reducing the gas concentration in the processing space. The gas separation apparatus 1 includes a separation chamber 2 constituting a first space S1, a pressure reduction chamber 3 constituting a second space S2, and a connection passage 4 connected such that the separation chamber 2 and the pressure reduction chamber 3 communicate with each other. A gas separator 5 disposed in the connection passage 4 so as to divide between the separation chamber 2 and the decompression chamber 3, a blower 6 for sending a gas to be treated including a gas to be separated to the separation chamber 2, and a decompression chamber And a decompression pump 7 for decompressing the inside of the apparatus.

  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 through a pipe 10. The pressure reducing chamber 3 has a suction port 8 B and a discharge port 9 B, and the discharge port 9 B is connected to the pressure reducing pump 7 through a pipe 11. A treated gas such as air including the gas to be separated is sent to the first space S1 in the separation chamber 2 through the pipe 10 by operating the blower 6. The gas to be treated may be, for example, a room for reducing the concentration of the gas to be separated such as water vapor or organic solvent gas, the inside of the apparatus, the inside of a plant (closed space etc.), a storage space, a storage space, etc. It is introduced into the blower 6 through 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 through the pipe 13.

  The second space S2 in the decompression chamber 3 operates the decompression pump 7 to generate the pressure in the separation chamber 2 (the pressure in the first space S1) and the pressure in the decompression chamber 3 (the second space S2). The pressure is reduced so as to make a difference with the pressure). A gas such as water vapor or an organic solvent-based gas separated from the gas to be treated is discharged through a pipe 14 connected to a decompression pump 7. The separated gas (the gas that has permeated the decompression chamber 3) is released to the atmosphere or recovered as needed. A pipe 15 is connected to the suction port 8B of the decompression chamber 3 so as to reduce the pressure while taking in external air and the like inside the decompression chamber 3. The pipe 15 may be provided with a valve (not shown) as needed. Moreover, the piping 15 can be omitted depending on the case.

  The gas separator 5 will be described with reference to FIGS. 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 a fine structure of the gas separator 5, and FIG. 5 is another example of a fine structure 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 21 and a porous membrane 22 provided on one side of the porous base 21. The porous substrate 21 has an upper surface 21a, a lower surface 21b opposed to the upper surface 21a, and a plurality of pores (not shown in FIG. 2) communicating from the upper surface 21a to the lower surface 21b. The porous membrane 22 is provided on at least one of the upper surface 21 a and the lower surface 21 b of the porous substrate 21 so as to block at least a part of the plurality of pores of the porous substrate 21. Although FIG. 2 shows a state in which the porous film 22 is formed on the upper surface 21 a of the porous substrate 21, the present invention is not limited to this, and the porous film 22 is provided on the lower surface 21 b of the porous substrate 21. It may be provided on both the upper surface 21a and the lower surface 21b.

  The porous membrane 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 21 a and the lower surface 21 b) of the porous substrate 21. The porous membrane 22 has a contact surface 22a in contact with the porous substrate 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 are exposed from the contact surface 22a to the exposed surface 22b. Are familiar with. The micropores provided in the porous membrane 22 form, for example, a wet seal to form a movement path of the gas to be separated, as will be described in detail later, and the gas to be separated has a contact surface in the micropores. By moving from 22a to the exposed surface 22b or from the exposed surface 22b to the contact surface 22a, separation target gas such as water vapor or organic solvent gas is separated from the gas to be treated. The wet seal of fine holes is formed as needed, and in some cases, it is possible to separate water vapor and the like without forming a wet seal.

  In the gas separator 5 according to the embodiment, as shown in FIGS. 3 and 4, a portion 22X of the porous membrane 22, in other words, a portion of the fibrous inorganic material that constitutes the porous membrane 22. It penetrates into the pore 23 along the inner wall 23 a of the pore 23 of 21. The average penetration depth of the intrusion portion 22X of the porous membrane 22 into the pores 23 is equal to or more than the average thickness of the porous membrane 22. By causing a portion 22X of the porous membrane 22 to enter the pores 23 along the inner wall 23a more than the average film thickness, the cracks of the porous membrane 22 and the porous base 21 of the porous membrane 22 can be obtained. Peeling can be suppressed. If the average penetration depth of the porous membrane 22 into the pores 23 is less than the average thickness of the porous membrane 22, cracking and peeling of the porous membrane 22 can not be sufficiently suppressed.

  As the shape of the invading portion 22X of the porous membrane 22 with respect to the pores 23 of the porous base material 21, as shown in FIG. 3, a part of the porous membrane 22 is a pore along the inner wall 23a of the pores 23. The shape which penetrated in the depth direction of 23 is mentioned. In this case, the porous membrane 22 is formed not only to close the portion of the pore 23 opened on the upper surface 21 a but also to close the open portion of the pore 23 extending in various directions in the porous substrate 21. Thus, the absorbability of the gas to be separated by the porous membrane 22 and the separability based thereon can be improved. Furthermore, as shown in FIG. 4, the shape of the intruding portion 22X with respect to the pores 23 of the porous membrane 22 is a shape in which a part of the porous membrane 22 exists so as to block the inside of the pores 23 It is also good. In addition to the porous membrane 22 that blocks the inside of the pores 23 of the porous membrane 22 in addition to the porous membrane 22 that blocks the top open portion of the pores 23, the pores 23 are doubly closed, so the gas to be separated Absorbability and separability based thereon can be further enhanced. The shape of the portion 22Y that blocks the inside of the pore 23 with the porous membrane 22 is not limited to the double structure shown in FIG. 4, but may be triple or more.

  Further, regarding the amount of penetration of the porous membrane 22 into the pores 23, the fibrous inorganic substance of the portion X intruding into the pores 23 with respect to the mass A of the fibrous inorganic substance constituting the porous membrane 22 portion It is preferable to set so that the ratio B of mass B of (B / A) becomes 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 substrate 21 and the porous membrane 22 is reduced, but also the gas separation rate is reduced. When the B / A ratio is 1 or more, the portion of the porous membrane 22 that does not contribute to gas separation increases, so that 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 is measured as follows. Six points in the porous membrane 22 are randomly selected from the gas separator 5. The cross section of each selected point is observed by a cross section SEM (Scanning Electron Microscope), a STEM (Scanning Transmission Electron Microscope), or a cross section TEM (Transmission Electron Microscope) to obtain an observation image. A straight line is drawn in the film thickness direction within the film of the observation image, and the length at which the distance between the two points intersecting the upper and lower surfaces of the film is the shortest is determined. The average distance is calculated by obtaining the shortest distance between two points intersecting the upper surface and the lower surface at three or more places in one field of view. The average value of the shortest distance between two points is determined in each of the selected six fields of view, and the average value of these values is taken as the average film thickness of the porous film 22.

  The average penetration depth to the pores 23 of the porous membrane 22 is measured as follows. Six points in the porous membrane 22 are randomly selected from the gas separator 5. The cross section of each selected point is observed by a cross section SEM or a cross section TEM to obtain an observation image. In the observation image, it is specified how far the porous membrane 22 has penetrated in the depth direction of the porous substrate 21, and the shortest distance between the tip of the penetration part and the surface of the porous substrate 21 is determined. The shortest distance between the tip of the penetration portion and the substrate surface is determined for all the penetration portions in the observation image, and the maximum value among them is selected. The distance (maximum value) of the tip of the intrusion portion is determined in each of the selected six fields of view, and the average value of these values is taken as the average penetration depth to the pores 23 of the porous film 22. Further, the B / A ratio determines the cross-sectional area A ′ of the porous film 22 and the cross-sectional area B ′ of the intruding portion 22X into the pores 23 from the observation image in which the penetration depth is determined. It is determined from '/ sectional area A').

  The constituent material of the porous substrate 21 is not particularly limited, and the function as a support of the porous membrane 22 composed of the fibrous inorganic substance can be maintained, and the gas to be treated containing the gas to be separated What is necessary is just to consist of a material which does not prevent passage of. As a constituent material of the porous base material 23, a ceramic material such as an oxide type, a nitride type, an oxynitride type, and a carbide type, a resin material, a carbon material, a metal material or the like is used. Specific examples of the porous substrate 21 include porous ceramics, organic porous bodies, carbon fiber molded bodies, molded bodies of synthetic fibers and natural fibers (including paper), nonwoven fabrics and the like. Specific constituent materials of the porous substrate 21 include aluminum (Al), silicon (Si), zinc (Zn), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), titanium Group consisting of oxides, nitrides, carbides, and silicates of (Ti), zirconium (Zr), nickel (Ni), cobalt (Co), iron (Fe), chromium (Cr), or copper (Cu) And at least one compound selected from these, which may constitute a mixture or a complex.

  When a porous ceramic is used as the porous substrate 21, the constituent particles of the porous ceramic may be a general spherical or granular particle having a shape close to it, but a plate-like particle is more preferable . The plate-like particles constituting the porous ceramic preferably have a shape in which the aspect ratio of the cross section is 2 or more, and more preferably, the shape in which the aspect ratio of the cross section is 4 or more. By using porous ceramics composed of such plate-like particles as the porous base material 21, a part of the porous membrane 22 can be easily made to penetrate along the inner wall of the pores 23. Further, also in the case of using a fiber aggregate or a molded body as the porous substrate 21, it is preferable that the fibers constituting the porous substrate 21 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.

  With respect to the shape of the porous substrate 21, the average pore diameter is 0.15 μm to 50 μm, and the volume porosity (volume ratio of pores in the porous substrate 21) is 20% to 70%. Is preferred. When the average pore size of the porous substrate 21 is less than 0.15 μm, the passability of the gas to be treated containing the gas to be separated tends to be reduced. Furthermore, when the average pore diameter of the porous substrate 21 is too small, when the porous film 22 is formed thereon, it depends on the average diameter and the average length of the fibrous inorganic substance, but in the pores 23 The fibrous inorganic substance can not be sufficiently infiltrated. From such a point, the average pore diameter of the porous substrate 21 is more preferably 0.5 μm or more. In addition, when the average pore diameter of the porous substrate 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 be deteriorated. Furthermore, if the average pore diameter of the porous substrate 21 is too large, the formability of the porous membrane 22 thereon may be reduced, and the gas separation performance by the porous membrane 22 may not be sufficiently obtained. From such a point, the average pore diameter of the porous substrate 21 is more preferably 20 μm or less.

  In addition, when the volume porosity of the porous base material 21 is less than 20%, the amount of the gas to be treated which can pass through the porous base material 21 decreases, and the absorption amount of the gas to be separated from the separation chamber 2 and the pressure reduction The amount of the gas to be separated into the chamber 3 may be insufficient. Furthermore, when the volume porosity of the porous substrate 21 is too small, when the porous film 22 is formed thereon, the fibrous inorganic material can not sufficiently penetrate into the pores 23. From such a point, the volume porosity of the porous substrate 21 is more preferably 30% or more. In addition, when the volume porosity of the porous base material 21 exceeds 70%, the strength of the porous base material 21 is reduced, which may hinder the continuous operation of the gas separation device 1. Furthermore, when the volume porosity of the porous substrate 21 is too large, the formability of the porous membrane 22 thereon is reduced, and the gas separation performance by the porous membrane 22 can not be sufficiently obtained. From such a point, the volume porosity of the porous substrate 21 is more preferably 60% or less. In addition, the volume porosity of the porous base material 21 and the shape (average pore diameter) of the pores 23 represent values measured by the mercury intrusion method.

  The thickness of the porous substrate 21 is not particularly limited, but is preferably in the range of 30 μm to 3 mm. If the thickness of the porous substrate 21 is too thin, deformation such as deflection may occur during handling, which may cause defects such as cracks in the porous film 22 as well as breakage. In addition, if the thickness of the porous substrate 21 is too thick, the permeation rate of the gas to be separated, such as the water vapor permeation rate, will be low, and not only the gas separation performance will deteriorate but also the thermal conductivity will decrease. A loss easily occurs in heat exchange when separating the target gas from the processing gas. The overall shape of the porous substrate 21 is not particularly limited, and various shapes such as a disk shape (cylindrical shape) or a rectangular shape can be applied according to the configuration of the gas separation device 1.

  The fibrous inorganic material 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. Although the air containing separation object gas is mentioned as a to-be-processed gas containing these separation object gas, It is not necessarily limited to this. Examples of organic solvent gases include methanol, ethanol, n-propanol, i-propanol, n-butanol, i-butanol, s-butanol, t-butanol, ethyl acetate, n-ethyl acetate, i-butyl formate, acetone, Vapors such as methyl ethyl ketone, methyl isobutyl ketone, diethyl ether, diisopropanol, trichloroethylene, n-hexane and the like can be mentioned.

  When the gas to be separated is water vapor, the fibrous inorganic material constituting the porous membrane 22 is preferably a hydrophilic material. As a constituent material 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 and phosphates.

  Examples of 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, and Sr, etc. Compounds such as carbonates, phosphates such as Mg, Ca, Sr, etc., or complexes or mixtures thereof can be used. Alternatively, the metal compound may be a metal compound in which the OH group is controlled by using a metal hydroxide as a precursor, bonding the same by hydrolysis or the like, and stopping the reaction on the way. Specific examples of constituent materials of fibrous inorganic substances include alumina (including hydrate), silica, titania, zirconia, magnesia, calcia, zinc oxide, ferrite, barium titanate and the like, and fibrous inorganic substances As specific examples of the metal hydroxide fiber of metal such as Al, Cu and Zn, oxide fiber such as alumina and silica, metal fiber and the like can be mentioned. More preferably, the fibrous inorganic substance further comprises at least one selected from the group consisting of boehmite and pseudoboehmite. Since boehmite (AlOOH) and pseudo-boehmite, which are hydrates of alumina, are excellent in affinity with water, they can absorb water vapor by forming the porosity film 22 with a fibrous material of boehmite or pseudo-boehmite. Separability can be enhanced.

  When the gas to be separated is an organic solvent gas, in the fibrous inorganic substance, composite material particles in which an additive element that breaks the charge balance is introduced into the lattice of hydrophilic compound particles described above, or in the lattice of hydrophilic compound particles Defect-introduced material particles in which atomic vacancies such as oxygen vacancies are introduced are used. The hydrophilic compound is as described above, and titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), chromium (Cr) may be added as an additive element introduced into the lattice of such compound particles. And manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn) and the like. However, elements overlapping with the cationic elements constituting the compound particle are excluded. By introducing these elements into the lattice or introducing oxygen vacancies into the lattice, affinity to the organic solvent 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 to 10 nm, and the average length l is preferably 0.5 μm to 10 μm. In the porous film 22 made of such a fibrous inorganic substance, micropores are formed in the interstices of the fibrous inorganic substance. The average pore diameter of the porous membrane 22 is preferably 1 nm or more and 40 nm or less. By forming the porous film 22 with a fibrous inorganic material having an average diameter d in the range of 1 to 10 nm, formation of micropores having an average pore diameter as described above in the porous film 22 in an appropriate amount Can. The average diameter d of the fibrous inorganic material is more preferably in the range of 2 nm to 10 nm.

  According to the porous film 22 having fine pores as described above, the liquefied substance of the gas to be separated, for example, water if it is water vapor, or the organic solvent if it is an organic solvent-based gas, is held in the fine pores, A wet seal can be formed in the membrane 22. The gas to be separated from the gas to be treated 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 is the pressure difference between the separation chamber 2 and the decompression chamber 3 By discharging the gas into the pressure reducing chamber 3 based on the gas to be treated, it is possible to separate the gas to be separated. The gas separator 5 having the porous membrane 22 may contain a liquefied material of the gas to be separated from the beginning, or may contain a liquefied material when the gas separator 5 is used.

  Although depending on the average pore size and volume porosity of the porous substrate 21, the porous membrane 22 is formed by using a fibrous inorganic substance having an average length 1 of 0.5 to 10 μm. A part of these can be well penetrated into the pores of the porous substrate 21. When the average length l of the fibrous inorganic material exceeds 10 μm, the fibrous inorganic material can not sufficiently penetrate into the pores. When the average length l of the fibrous inorganic substance is less than 0.5 μm, the formability of the porous membrane 22 is reduced, and the function as the gas separator 5 is reduced. The average length l of the fibrous inorganic substance is more preferably 1 μm or more and 3 μm or less. The average length l of the fibrous inorganic material is preferably set in consideration of the average pore diameter of the porous substrate 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 substrate 21 is 2 times to 30 times the average length l of the fibrous inorganic substance. The average pore diameter of the porous substrate 21 is more preferably 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, the liquefied matter of the gas to be separated can be easily held in the fine pores which are the passage of the gas to be separated As a seal is easily formed, 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 be reduced. In addition, when the average pore diameter of the porous membrane 22 exceeds 40 nm, the formability of the wet seal is reduced, and the balance between absorption of the gas to be separated from the separation chamber 2 and release of the gas to be separated into the decompression chamber 3 And the gas separation performance tends to decrease. 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 made of the fibrous inorganic material 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 membrane 22 is less than 0.5 μm, the amount of wet seal formation and the like may be insufficient, and there may be a possibility that sufficient gas separation performance can not be obtained. In addition, 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 film 22 is more preferably 5 μm or more and 25 μm or less.

  The average pore size of the porous membrane 22 can be evaluated by the BJH (Barrett, Joyner, Hallender) method of physical gas adsorption. In addition, since the average diameter of the fibrous material in the porous deposited layer of the fibrous material is 2 to 4 times the average pore diameter, the average diameter of the fibrous inorganic material can be determined as a converted value from the average pore diameter . The fact that the porous membrane 22 is composed of a fibrous inorganic material can be confirmed by bending and breaking the gas separator 5 having the porous membrane 22 and observing the fibrous structure of the fractured surface. When a flexible porous substrate 21 is used, the porous film 22 is torn by large bending, so that it is confirmed by observing the film surface of such porous film 22 by SEM that it has a fibrous structure can do. Moreover, since the crystal structure can be specified by analyzing the film surface by XRD, the composition of the porous film 22 can specify the constituent material of the porous film 22.

The gas separator 5 composed of the porous substrate 21 having the porous membrane 22 described above has a size of 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 made better through the wet seal formed in the porous membrane 22. It can be moved into the decompression chamber 3. When the air permeability K of the composite member 21 is less than 1 × 10 ^-16 m ² , the permeation rate of the gas to be separated is reduced. When the air permeability K exceeds 1 × 10 ⁻¹² m ² , air leakage occurs, the wet sealability is reduced, and the separation rate α of the gas to be separated and the like are easily reduced. 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, air permeability K is the air of a constant volume is passed through the vertical direction of the sample, the inflow and outflow of the pressure difference [Delta] P [Unit: kPa] ^when: from [cm 3 / min Units and flow rate _{Q air} , It is calculated | required based on the following (1) Formula. In equation (1), δ is the thickness of the sample, A is the area of the sample, and μ _air is the viscosity of air (18.57 μPa · s).
K = (Q _air / ΔP) · (μ _air / A) · δ (1)

  When the gas separator 5 is used as a water vapor separator, the water vapor separator (5) may be provided with a water-soluble hygroscopic agent present in the micropores of the porous membrane 22. Since the water-soluble hygroscopic agent absorbs and holds moisture, it becomes easy to form a wet seal in the porous membrane 22. As the water-soluble hygroscopic agent, citrates, carbonates, phosphates, halides, oxide salts, hydroxides, sulfates and the like of Group 1 elements 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 fine pores, or may be thinly and uniformly attached to the whole or a part of the inner wall of the fine pores. The water vapor separator (5) may be provided with a gas adsorption liquid such as an ionic liquid present 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), odor Potassium iodide (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), phosphoric acid Thorium _(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 ) and the like, sodium sulfate (Na ₂ SO ₄ ), potassium sulfate (K ₂ SO ₄ ), lithium sulfate (Li ₂ SO ₄ ) and the like, and hydrates of these.

  The gas separator 5 used in the gas separation device 1 may be supported by a gas-permeable support 31 as shown in FIG. Although FIG. 5 shows a state in which the pair of supports 31 are arranged along both surfaces of the gas separator 5, the supports 31 may be arranged along only one side of the gas separator 5. For the support 31, for example, paper, punching metal, polyimide porous body or the like is used, and mesh-like substances 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 thereto.

  The to-be-treated gas 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 pressure reducing pump 7 simultaneously with the blower 6 and reducing the pressure in the pressure reducing chamber 3, a difference is generated between the pressure in the separation chamber 2 and the pressure in the pressure reducing chamber 3. Due to this pressure difference, the partial pressure of the separation target gas such as the water vapor pressure in the decompression chamber 3 (the partial pressure of the separation target gas in the second space S2 (hereinafter, also simply referred to as gas partial pressure)) It becomes smaller than gas partial pressure (gas partial pressure of 1st space S1), such as water vapor pressure. Since the gas separator 5 forms a wet seal by the liquefied matter of the gas to be separated held in the micropores of the porous membrane 22, a gas partial pressure difference is generated between the inside of the separation chamber 2 and the inside of the decompression chamber 3. By generating the gas, movement of the gas to be separated occurs between the separation chamber 2 and the pressure reduction chamber 3 disposed via the gas separator 5.

  In order to cause the movement of the gas to be separated through the gas separator 5, the pressure reducing chamber 3 is reduced by the pressure reducing pump 7 so that the pressure in the pressure reducing chamber 3 becomes -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 decompress the inside of the decompression chamber 3 such that the difference between the pressure in the separation chamber 2 and the pressure in the decompression chamber 3 is 50 kPa or more. If the pressure difference is less than 50 kPa, there is a possibility that the movement of the gas to be separated from the separation chamber 2 into the decompression chamber 3 can not be sufficiently promoted. Furthermore, 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 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 necessarily the case because it also depends on the vapor pressure of the gas to be separated.

  In the gas separation device 1 shown in FIG. 1, although the gas partial pressure difference is generated between the separation chamber 2 and the decompression chamber 3 by the decompression pump 7 that decompresses the inside of the decompression chamber 3, the adjustment unit of the gas partial pressure is It is not limited to this. For example, dry air or heated air may be introduced into the decompression chamber 3 (second space S2). Also by this, a gas partial pressure difference such as a water vapor pressure difference can be generated between the separation chamber 2 and the decompression chamber 3. In the gas separation apparatus 1 shown in FIG. 1, the gas pressure adjusting unit that generates a gas partial pressure difference between the separation chamber 2 and the decompression chamber 3 is not particularly limited, and the 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 partial pressure of gas is a wet seal formed in the gas separator 5, specifically, the fine pores of the porous membrane 22. It is absorbed by the liquefied matter of the held separation target gas. The liquefied matter of the gas to be separated in the gas separator 5 permeates into the decompression chamber 3 having a relatively low partial pressure of gas. The gas to be separated contained in the gas to be treated in the separation chamber 2 by the balance between the gas partial pressure in the separation chamber 2, the gas partial pressure in the pressure reduction chamber 3, and the amount of liquefied material of the gas to be separated in the gas separator 5 The absorption by the gas separator 5 and the discharge of the gas to be separated in the gas separator 5 into the decompression chamber 3 occur successively.

  The absorption of the gas to be separated by the gas separator 5 described above and the discharge of the gas to be separated in the gas separator 5 into the decompression chamber 3 continuously occur, so that the inside of the separation chamber 2 (first space S1) It is possible to continuously reduce the concentration of the gas to be separated, and further the concentration of the gas to be treated in the processing space connected to the separation chamber 2 via the blower 6. 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 for dehumidification. The to-be-treated gas such as air whose gas concentration has been reduced is returned from the separation chamber 2 to the to-be-treated space. The separation target gas 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. If the gas to be separated is water vapor, the water that has permeated into the decompression chamber 3 may be sent to a third space such as a room that requires humidification. When the gas to be separated is an organic solvent gas, the organic solvent and the gas thereof are recovered as necessary.

  In the gas separation device 1 of the embodiment, since the gas separator 5 forms a wet seal, only the separation target gas contained in the gas to be treated such as air in the separation chamber 2 is moved into the decompression chamber 3 It can be done. For example, when the gas separation apparatus 1 is used as a dehumidifier, 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 processing space to be dehumidified is hardly changed. By dehumidifying the interior of the space without substantially changing the temperature of the space to be treated, there is no risk of lowering the thermal efficiency, for example, even when used in combination with cooling of the space. It is possible to increase the thermal efficiency when using the dehumidifier together with cooling.

The gas separator 5 shown in FIGS. 2 to 4 is formed on the surface of the porous substrate 21 and at least one of the surfaces as described above, and consists of a deposited layer of fibrous inorganic material, and between fibrous inorganic materials. And a porous membrane 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 can be favorably 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, the transmission rate V of the separation object gas can be improved while maintaining the practical separation ratio α of the separation object gas, for example, about 3 to 100. As a result, it is possible to provide the gas separator 5 having performance, strength, reliability and the like that can be practically applied to air conditioning and the like, and the gas separator 1 that does not require regeneration treatment using the same.

The separation rate α of the gas is, for example, the ratio of the amount of permeated liquid of the 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), (N 3 _liquid / N 3 _air ) is the molar ratio of the liquefied matter of the gas contained in the gas to be treated (air) to be supplied to the separation chamber 2 (first space S 1) to the dry air, (N 4 _liquid / N4 _air) is the molar ratio of the dry air and the liquefied material of the gas contained in the gas to be treated (air) discharged from the vacuum chamber 3 (second space S2). If α is 1, it means that the liquefied material (water and the like) of the gas and the dry air flow at the same ratio from the separation side space S1 to the pressure reduction side space S2. If α is 100, it means that the permeation of dry air is reduced to 1/100 with respect to the permeation of liquefied matter (water and the like) of gas from the dehumidification side space S1 to the decompression side space S2.

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

Second Embodiment
Next, a configuration example using the gas separation device 1 according to the first embodiment as a dehumidifier 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 air inlet Ra. The dehumidifying device 1 is provided in the room R in order to remove water vapor (water) from the air of the space Rx to be dehumidified. The dehumidifier 1 shown in FIG. 6 has a structure in which a pipe 15 for taking in external air is connected to the decompression chamber 3 (second space S2). In the dehumidifier 1, the inside of the decompression chamber 3 is decompressed while taking in external air into the decompression chamber 3. The pipe 15 has a valve 16. The piping 15 may be omitted.

  The air in the space Rx is basically composed of water vapor (moisture) and dry air. The air in the space Rx is sent into the separation chamber (dehumidifying chamber) 2 of the dehumidifier 1 through the pipes 12 and 10 by operating the blower 6. The air dehumidified 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 absorption of moisture in the air in the separation chamber 2 by the gas separator 5 and release of moisture in the gas separator 5 to the decompression chamber 3 occur continuously, such continuous dehumidification without regeneration is realized. Dehumidification performance such as dehumidification speed can be enhanced. Therefore, it is possible to provide a practical and efficient dehumidifier 1.

  The application structure of the dehumidifier 1 of the embodiment is not limited to the structure shown in FIG. The dehumidifying device 1 of the embodiment can be variously modified. Although 1st space S1 was set as the separation chamber 2 of the dehumidifier 1 in FIG. 6, 1st space S1 is not limited to this. As shown in FIG. 7, the first space S1 may be the dehumidifying target space Rx itself. That is, the decompression chamber 3 to be the second space S2 may be disposed via the target space Rx to be the first space S1 and the gas separator 5. In this case, by decompressing the decompression chamber 3, water vapor (moisture) is directly removed from the air of the target space Rx (first space S1) to be dehumidified. The settings of the first space S1 and the second space S2 can be changed variously.

In addition, the dehumidification speed V shows the value measured as follows. First, a space Rx is provided by a 1-liter container with a hole of 10 mm in diameter, in a constant temperature and humidity chamber in which the humidity and temperature are kept constant. In such a structure, the pressure of the second space with respect to the first space is set to -80 kPa by the dehumidifier (gas separation device) shown in FIG. The time when dehumidified to a low relative humidity is taken as the area-converted value of the water vapor separator (gas separator). The measurement temperature is 40 ° C., and the working 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 decreases from 70% to 60% is one hour, the dehumidifying speed V is 10% / h.

  Next, Examples and their evaluation results will be described.

Example 1
First, as a porous substrate, a disc-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 solution F1000 (average diameter d = 4 nm, average length l = 1.4 μm), manufactured by Kawaken Fine Chemical Co., Ltd.) is used as a slide glass on one surface of this alumina ceramic porous body After coating by the cast method, drying at 40 ° C., and heat treatment at 200 ° C., a gas separator was produced by forming a porous membrane composed of a fibrous inorganic substance containing boehmite.

The shape and characteristics of the gas separator made of the alumina ceramic porous body having the above-mentioned 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, the boehmite phase was confirmed. The average film thickness and the average pore diameter of the porous membrane were measured according to the method described above, and the average film thickness was 17 μm and the average pore diameter was 1.4 nm. The average diameter of the fibrous inorganic substance as calculated 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. Furthermore, in cross-sectional TEM observation of the porous film, it was confirmed that a part of the porous film made of a fibrous inorganic substance penetrates into the pores of the alumina ceramic porous body serving as the base material. The average penetration depth into the pores of the porous membrane and the ratio (B / A) of the mass B of the intruding portion to the membrane mass A are measured according to the method described above. / A was 0.5.

When the water vapor separation rate α and the water vapor transmission rate V were measured using the above-described gas separator as a water vapor separation body, the temperature of the supplied air to the dehumidification side was 40 ° C., and under the conditions of saturated steam, the water vapor separation rate α> The water vapor transmission rate V was 590 g / h / m ² . In addition, the gas separator was used as a water vapor separator to perform dehumidification in a 1 liter container. When the inside of the container was depressurized and dehumidified through the separator for 1 hour, the relative humidity was 90%, and the humidity before dehumidification was reduced to 30%, and the dehumidification rate was 60% / h. Furthermore, when the dehumidification test was repeated several times, the same result was obtained in each case.

(Example 2)
The same fibrous boehmite dispersion (alumina sol F1000) as in Example 1 is dip-coated on the same alumina ceramic porous body as in Example 1, dried at 40 ° C., and then heat-treated at 200 ° C. A porous film comprising a fibrous inorganic material containing boehmite was formed. The dipping and drying of the fibrous boehmite dispersion were repeated three times.

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

When the water vapor separation rate α and the water vapor transmission rate V were measured using the above-described gas separator as a water vapor separation body, the temperature of the supplied air to the dehumidification side was 40 ° C., and under the conditions of saturated steam, the water vapor separation rate α> The water vapor transmission rate was 100 g / h / m ² . In addition, the gas separator was used as a water vapor separator to perform dehumidification in a 1 liter container. When the inside of the container was depressurized and dehumidified through the separator for 1 hour, the relative humidity was 90%, and the humidity before dehumidification was reduced to 30%, and the dehumidification rate was 60% / h. Furthermore, when the dehumidification test was repeated several times, the same result was obtained in each case.

(Example 3)
The same fibrous boehmite dispersion (alumina sol F1000) as in Example 1 is spray coated onto the same alumina ceramic porous body as in Example 1, dried at 40 ° C., and then heat treated at 200 ° C. A porous film comprising a fibrous inorganic material containing boehmite was formed. The spraying and drying of the fibrous boehmite dispersion were repeated three times.

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

When the water vapor separation rate α and the water vapor transmission rate V were measured using the above-described gas separator as a water vapor separation body, the temperature of the supplied air to the dehumidification side was 40 ° C., and under the conditions of saturated steam, the water vapor separation rate α> The water vapor transmission rate V was 770 g / h / m ² . In addition, the gas separator was used as a water vapor separator to perform dehumidification in a 1 liter container. When the inside of the container was depressurized and dehumidified through the separator for 1 hour, the relative humidity was 90%, and the humidity before dehumidification was reduced to 20%, and the dehumidification rate was 70% / h. Furthermore, when the dehumidification test was repeated several times, the same result was obtained in each case.

(Example 4)
Using a gas separator produced in the same manner as in Example 1, a separation experiment of IPA was performed from a mixed solution of isopropyl alcohol (IPA) and water. As a mixed solution, a mixture of IPA: water = 10: 90 (% by mass), that is, a 10% aqueous solution of IPA is used, which is vaporized and filled in a closed vessel, and the gas separating apparatus shown in FIG. Gas separation was performed by reducing the pressure to 90 kPa. The experiment was performed in a 40 ° C. thermostat. The gas which permeated the gas separation membrane was cooled and liquefied with a refrigerant of acetone and dry ice, and the concentration was measured. It was confirmed that the gas was an 80% IPA solution. Furthermore, when the above-described gas separation test was repeated several times, similar results were obtained in all cases.

(Comparative example 1)
As a 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 (alumina sol solution F1000) as in Example 1 was applied to one surface of this alumina ceramic porous body by a cast method using a slide glass and dried at 40 ° C., 200 By heat treatment at ° C, a porous film composed of a fibrous inorganic substance was formed.

  The gas separator made of the alumina ceramic porous body having the above-mentioned porous membrane was used as a water vapor separator to perform dehumidification in a 1 liter container. When the inside of the container was depressurized and dehumidified through the separator for 1 hour, the relative humidity was 90%, and the humidity before dehumidification was reduced to 50%, and the dehumidification rate was 40% / h. Moreover, when the dehumidification test was done again, 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 film, a part of the porous film made of a fibrous inorganic substance penetrates into the pores of the alumina ceramic porous body serving as the base material, but the inside of the pores of the porous film The average penetration depth was 5 μm.

(Comparative example 2)
As a 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 (alumina sol solution F1000) as in Example 1 was applied to one surface of this alumina ceramic porous body by a cast method using a slide glass and dried at 40 ° C., 200 By heat treatment at ° C, a porous film composed of a fibrous inorganic substance was formed.

  The gas separator made of the alumina ceramic porous body having the above-mentioned porous membrane was used as a water vapor separator to perform dehumidification in a 1 liter container. When the inside of the container was depressurized and dehumidified through the separator for 1 hour, dehumidifying performance was not obtained. When the surface of the gas separator was visually observed, the porous film was not uniformly formed, and pits such as pores were observed in some places. In addition, when the porous membrane was observed by SEM, a membrane structure which blocks the pores of the porous body as shown in FIG. 3 and FIG. 4 was not observed.

  While certain embodiments of the invention have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the invention. These novel embodiments can be implemented in other various forms, and various omissions, replacements and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and the gist of the invention, and are included in the invention described in the claims and the equivalent scope thereof.

  DESCRIPTION OF SYMBOLS 1 ... Gas separation apparatus, 2 ... Dehumidification room, 3 ... Decompression room, 4 ... Connection path, 5 ... Gas separation body, 6 ... Blower, 7 ... Decompression pump, 21 ... Porous base material, 22 ... Porous membrane, 23 ... pore, S1 ... first space, S2 ... second space.

Claims (14)

A porous substrate having a first surface, a second surface opposite to the first surface, and pores communicating with the first surface to the second surface;
A porous membrane 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,
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 to the pores is the average thickness of the porous membrane More than that, gas separators.   The gas separator according to claim 1, wherein the fibrous inorganic substance has an average diameter of 1 nm to 10 nm.   The gas separator according to claim 1 or 2, wherein an 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 an average film thickness of the porous film is 0.5 μm or more and 50 μm or less.   The fibrous inorganic substance is an oxide, nitride, carbide, hydroxide, silicic acid of aluminum, silicon, zinc, magnesium, calcium, strontium, barium, titanium, zirconium, nickel, cobalt, iron, chromium or copper. The gas separator according to any one of claims 1 to 4, comprising at least one selected from the group consisting of a salt, a carbonate and a phosphate.   The gas separator according to any one of claims 1 to 4, wherein the fibrous inorganic substance comprises at least one selected from the group consisting of boehmite and pseudoboehmite.   The gas separator according to any one of claims 1 to 6, wherein an 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 7, wherein a volume porosity of the porous substrate is 20% or more and 70% or less.   The porous substrate comprises an oxide, nitride, carbide, or silicate of aluminum, silicon, zinc, magnesium, calcium, strontium, barium, titanium, zirconium, nickel, cobalt, iron, chromium, or copper The gas separator according to any one of claims 1 to 8, comprising at least one selected from the group. The gas separator according to any one of claims 1 to 9, wherein the air permeability is 1 × 10 ^-16 m ² or more and 1 × 10 ^-10 m ² or less.   It is disposed between the first space and the second space, and the partial pressure of the separation target gas in the second space is lower than the partial pressure of the separation target gas in the first space, The gas separator according to any one of claims 1 to 10, wherein the gas separator is used as a gas separator that transmits the gas to be separated present in the first space to the second space. The first space,
A second space leading to the first space;
The gas separator according to any one of claims 1 to 10, which is provided to divide between the first space and the second space.
A gas pressure for adjusting a partial pressure of the separation target gas of the second space such that a partial pressure of the separation target gas of the second space is lower than a partial pressure of the separation target gas of the first space Equipped with an adjustment unit,
A gas separation apparatus, wherein the gas to be separated present in the first space is allowed to permeate to the second space via the gas separator.   The gas separation apparatus according to claim 12, wherein the gas pressure adjusting unit includes a pressure adjusting mechanism configured to reduce the pressure of the second space from the pressure of the first space.   The gas separation apparatus according to claim 12, wherein the separation target gas is water vapor, and the water vapor present in the first space is allowed to permeate to the second space via the gas separator. .

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