JP2018150206A - Ceramic porous body, water vapor separator, and humidity control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ceramic porous body, a water vapor separator, and a humidity control device capable of practical and efficient dehumidification even in an environment with low humidity less than 60%.SOLUTION: A water vapor separator used for permeating water vapor present in a first space to a second space, includes a ceramic porous body 16 having a first surface, a second surface opposed to the first surface and pores communicating from the first surface to the second surface. The ceramic porous body 16 includes a porous matrix 19 formed by a plurality of first inorganic material particles 18 isotopically necking each other, and second inorganic material particles 20 arranged irregularly in the porous matrix 19 and having an average particle diameter three times or more than a maximum particle diameter of the first inorganic material particles. The volume fraction of the second inorganic material particles 20 is 0.001 to 10 vol.% of the volume of the first inorganic material particles.SELECTED DRAWING: Figure 3

Description

  Embodiments described herein relate generally to a ceramic porous body, a water vapor separator, and a humidity control apparatus.

  In air conditioning technologies such as home air conditioners, technologies have advanced in both refrigerant and energy efficiency, and a more comfortable living environment has been demanded accordingly. For this reason, not only the temperature but also the multifunctionalization of air conditioners such as humidity control, ventilation, airflow adjustment, and air purification is progressing. Improvement of energy efficiency has become the most important issue from the recent shortage of energy. In Asian countries with high temperature and high humidity, humidity adjustment, especially dehumidification, is considered to be important with the improvement of living standards, and air conditioning with low environmental impact is required by performing this with energy saving. In dehumidification by refrigerant cooling using a compressor or the like that is currently mainstream, a large amount of energy is required because air is cooled to condense water vapor, and the cooled air is reheated to adjust the temperature. For this reason, since the power consumption increases, the size of the environmental load is a problem.

  Gas separators such as desiccant air conditioners have better energy efficiency than refrigerant-type dehumidification because they absorb moisture in the room with a moisture absorber that absorbs water vapor and then heats it to discharge it outdoors. . As a hygroscopic material, for example, a porous material such as a ceramic porous material or zeolite is impregnated and supported with a deliquescent material made of chloride or bromide such as sodium, lithium, calcium or magnesium. However, since the hygroscopic material is saturated by continuing to adsorb water, regeneration processing is required. The regeneration process of the hygroscopic material is performed by heating the hygroscopic material and discharging water. It is inefficient to use the hygroscopic material regeneration treatment together with cooling.

  As an energy-saving and low-cost method that replaces the current air conditioning method, a continuous dehumidification method using a water vapor separator that does not require regeneration treatment has been studied. As a structure of a humidity control apparatus using a water vapor separator, a gas separator in which a liquid absorbent such as an aqueous lithium chloride solution is filled between two water vapor permeable membranes using polyethylene, fluororesin, or the like is conditioned. The structure arrange | positioned between spaces, such as indoors, and spaces, such as the outdoors, is mentioned, and transfer of water vapor | steam is performed between indoor air and a liquid absorbent through a water vapor permeable film. However, the water vapor permeable membrane is easily damaged, and furthermore, in this method, since the water vapor moving speed is slow, it is difficult to perform dehumidification efficiently.

  Further, the conventional continuous dehumidification method using the water vapor separator is aimed at dehumidification at a relatively high humidity of, for example, 60% or more, and the water vapor separator is also suitable for dehumidification at such humidity. It has a configuration. When such a water vapor separator is used, there is a problem that the humidity is lowered and the dehumidifying rate is lowered. For example, a good dehumidification rate can be obtained on the high humidity side where the relative humidity, which is regarded as important in air conditioning, is 70% or more, while the dehumidification rate rapidly decreases on the low humidity side where the relative humidity is less than 60%. When only indoor dehumidification is assumed, there is no particular problem, but when a continuous dehumidification method using a water vapor separator is applied to a device that requires lower humidity, such as a drying device, the dehumidification rate on the low humidity side Is a problem. In view of the above, there is a need for a water vapor separator that can increase the dehumidification rate even in a low humidity environment where the relative humidity is less than 60%, and a dehumidifying device using such a water vapor separator. Yes.

Japanese Patent Laid-Open No. 2006-176664 JP 2003-336863 A JP 7-328375 A JP 2006-327855 A

  The problem to be solved by the present invention is to provide a porous ceramic body, a water vapor separator, and a humidity control device that enable practical and efficient dehumidification even in a low humidity environment. .

  The porous ceramic body according to the embodiment includes a porous matrix configured by isotropic necking of a plurality of first inorganic material particles, and the ceramic porous body is irregularly disposed in the porous matrix. Second inorganic material particles having an average particle size of three times or more than the maximum particle size of the inorganic material particles, and the volume ratio of the second inorganic material particles is the volume of the first inorganic material particles. It is 0.001 volume% or more and 10 volume% or less.

  The water vapor separator according to the embodiment is disposed between the first space and the second space, and the water vapor pressure in the second space is lower than the water vapor pressure in the first space. A water vapor separator that allows water vapor existing in a first space to pass through the second space, the first surface, a second surface facing the first surface, and the first surface To a ceramic porous body having pores communicating with the second surface. The ceramic porous body includes a porous matrix configured by isotropic necking of a plurality of first inorganic material particles, and the first inorganic material is irregularly disposed in the porous matrix. Second inorganic material particles having an average particle diameter of 3 times or more than the maximum particle diameter of the particles, and the volume ratio of the second inorganic material particles is 0.001 volume of the volume of the first inorganic material particles. % To 10% by volume.

  The humidity control apparatus of the embodiment exposes the first space, the second space leading to the first space, the first surface to the first space, and the second surface to the first space. The steam separator according to the embodiment provided to partition the first space and the second space while being exposed to the second space, and the steam pressure of the second space is the first space. A water vapor pressure adjusting unit that adjusts the water vapor pressure of the second space so as to be lower than the water vapor pressure of the first space, and the water vapor existing in the first space is passed through the water vapor separator. It is a device that transmits through the second space.

It is a figure which shows the humidity control apparatus of embodiment. It is sectional drawing which shows the water vapor separator used for the humidity control apparatus shown in FIG. It is sectional drawing which expands and shows a part of water vapor separator shown in FIG. It is a figure for demonstrating the method to measure the particle size of the inorganic material particle which comprises the water vapor separator shown in FIG. It is sectional drawing which shows the usage example of the water vapor separator shown in FIG. It is a figure which shows the modification of the humidity control apparatus shown in FIG.

  Hereinafter, a ceramic porous body and a water vapor separator according to an embodiment and a humidity control apparatus using the ceramic porous body will be described with reference to the drawings. In each embodiment, substantially the same constituent parts 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 dimensions, the ratio of the thickness of each part, and the like may differ from the actual ones.

  FIG. 1 shows the configuration of the humidity control apparatus of the embodiment. A humidity control apparatus 1 shown in FIG. 1 functions as a dehumidification apparatus that removes water vapor (water) from the air in the space Rx to be processed. In FIG. 1, R indicates a room constituting the dehumidifying target space Rx, and the room R has an intake port Ra. The dehumidifying device (humidity adjusting device) 1 is provided in the room R in order to remove water vapor (water) from the air in the space Rx. The air in the space Rx is basically composed of water vapor (water) and dry air. The dehumidifying device 1 includes a dehumidifying module 2, a blower 3 that sends air in the space Rx to the dehumidifying module 2, and a decompression pump 4 that decompresses a part of the dehumidifying module 2. The space Rx and the blower 3 are connected by a pipe 5, the blower 3 and the dehumidifying module 2 are connected by a pipe 6, and the dehumidifying module 2 and the space Rx are connected by a pipe 7. The dehumidifying module 2 and the decompression pump 4 are connected by a pipe 8.

  The dehumidifying module 2 includes a dehumidifying chamber (first ventilation path) 9 that constitutes the first space S1, a decompression chamber (second ventilation path) 10 that constitutes the second space S2, a dehumidifying chamber 9, and a decompression chamber. It has the connection path 11 which connects the chamber 10, and the water vapor separator 12 arrange | positioned in the connection path 11 so that the dehumidification chamber 9 and the decompression chamber 10 may be partitioned off. In the dehumidifying chamber 9 of the dehumidifying module 2, the air in the space Rx is sent through the pipes 5 and 6 by operating the blower 3. The air dehumidified in the dehumidifying chamber 9 is returned to the space Rx via the pipe 7. The decompression chamber 10 is controlled by the decompression pump 4 so that a difference occurs between the pressure in the dehumidification chamber 9 (pressure in the first space S1) and the pressure in the decompression chamber 10 (pressure in the second space S2). Exhausted. A pipe 13 for taking in external air is connected to the decompression chamber 10, and the pipe 13 has a valve 14. The pipe 13 is connected to the decompression chamber 10 as necessary, and may not be installed depending on circumstances.

  As shown in FIG. 2, the water vapor separator 12 includes a ceramic porous body 16 having pores (open pores) 15 and water (not shown) present in the pores 15 of the ceramic porous body 16. It is preferable to provide. The water present in the pores 15 forms a wet seal on the water vapor separator 12. As will be described later in detail, by moving water from the dehumidification chamber 9 to the decompression chamber 10 through the water vapor separator 12 on which a wet seal is formed, in the air sent from the space Rx to the dehumidification chamber 9 Dehumidification is performed by reducing the amount of water. The water vapor separator 12 may include a water-soluble hygroscopic agent 17 present in the pores 15 of the ceramic porous body 16. The water-soluble hygroscopic agent 17 improves wet seal formation and will be described in detail later.

As another method, sealing is performed by coexisting a non-aqueous liquid that adsorbs water, and water is transferred from the dehumidification chamber 9 to the decompression chamber 10 via the water vapor separator 12 on which such a seal is formed. You may make it make it. Even in such a case, the space Rx can be dehumidified. Examples of the non-aqueous liquid include ionic liquids (imidazolium type, ammonium type, pyridinium type), but are not limited thereto. The water present in the pores 15 means all of the substance represented by the chemical symbol H ₂ O, or hydrates, deposits, and inclusions containing the substance. For example, ionic liquid containing water and triethylene glycol are also included.

  The ceramic porous body 16 has, for example, a rectangular parallelepiped shape, and is exposed to the first surface 16a exposed in the dehumidification chamber 9 (first space S1) and the decompression chamber 10 (second space S2). And has a second surface 16b. The pores 15 provided in the ceramic porous body 16 communicate from the first surface 16a to the second surface 16b. As shown in FIG. 3, the ceramic porous body 16 includes a porous matrix 19 formed by isotropic necking (bonding) of a plurality of first inorganic material particles 18, and a porous matrix 19. And the second inorganic material particles 20 arranged irregularly. The necked first inorganic material particles 18, including the second inorganic material particles 20, form a porous polycrystalline sintered body. The first inorganic material particles 18 and the second inorganic material particles 20 may be simply in contact with each other or may be partially necked. The second inorganic material particles 20 have an average particle diameter that is three times or more than the maximum particle diameter of the first inorganic material particles 18. The second inorganic material particles 20 are porous so that the ratio (V2 / V1) of the volume (V2) to the volume (V1) of the first inorganic material particles 18 is in the range of 0.001 to 10% by volume. Arranged in the matrix 19.

  Constituent materials of the first and second inorganic material particles 18 and 20 include aluminum (Al), silicon (Si), zinc (Zn), magnesium (Mg), calcium (Ca), barium (Ba), nickel ( Ni, Cobalt (Co), Iron (Fe), Chromium (Cr), Titanium (Ti), Zirconium (Zr), Copper (Cu) and other element oxides, nitrides, carbides, silicates, or these The composite compound of these is mentioned. The first inorganic material particles 18 and the second inorganic material particles 20 may be made of the same inorganic material (ceramic material) or may be made of different inorganic materials (ceramic material).

  The pores 15 of the ceramic porous body 16 preferably contain 50% by volume or more of pores having a pore diameter in the range of 1 nm to 10 nm, more preferably 70% by volume or more, and further 100% by volume. It is desirable to be. The average pore diameter of the pores 15 is preferably 0.5 nm or more and 50 nm or less, and more preferably 1 nm or more and 20 nm or less. The maximum pore diameter of the pores 15 is preferably 100 nm or less, and more preferably 50 nm or less. When the amount of pores having the above pore diameter is less than 50% by volume (for example, the volume ratio of pores having a pore diameter exceeding 50 nm is large), or when the maximum pore diameter exceeds 100 nm, the relative humidity is 60%. Dehumidifying performance in a low humidity environment, such as a decrease in wet sealability in a low humidity environment, such as below, or a decrease in the balance between moisture absorption from the dehumidification chamber 9 and moisture release to the decompression chamber 10 Cannot be raised sufficiently.

  The volume porosity of the ceramic porous body 16 and the shape of the pores 15 (pore volume fraction, average pore diameter, maximum pore diameter, etc.) basically indicate values measured by mercury porosimetry. However, when the pore diameter of the pores 15 is around 1 nm, such a pore diameter cannot be obtained by the mercury intrusion method. In such a case, the value evaluated by the BET method is used. Since the characteristics of the water vapor separator 12 are influenced by the volume porosity of the ceramic porous body 16, it is preferable to set the pore diameter of the pores 15 in consideration of the volume porosity.

  The volume porosity of the ceramic porous body 16 (volume ratio of the pores 15 in the ceramic porous body 16) is preferably in the range of 10 to 80%. If the volume porosity of the ceramic porous body 16 is less than 10%, the amount of water vapor that can pass through the pores 15 decreases, so that the amount of moisture absorbed from the dehumidifying chamber 9 and the amount of moisture released into the decompression chamber 10 are reduced. May be insufficient. If the volume porosity of the ceramic porous body 16 exceeds 80%, the strength of the ceramic porous body 16 may be reduced, and the continuous operation of the dehumidifier 1 may be hindered. From the viewpoint of the dehumidifying speed, the volume porosity of the ceramic porous body 16 is more preferably in the range of 10 to 50%, and further preferably in the range of 20 to 50%. However, the volume porosity of the ceramic porous body 16 is preferably set according to the properties required for the water vapor separator 12. For example, when it is desired to increase the dehumidifying rate, it is preferable to set the volume porosity relatively high. On the other hand, when it is desired to increase the mechanical strength of the water vapor separator 12 or to reduce the cost of the water vapor separator 12, it is preferable to set the volume porosity relatively low.

  The porous matrix 19 of the ceramic porous body 16 has pores 15 communicating from the first surface 16a to the second surface 16b as shown in FIGS. The average particle diameter of the first inorganic material particles 18 constituting the porous matrix 19 is preferably 100 nm or less. The average particle diameter of the first inorganic material particles 18 is more preferably 10 to 100 nm. By forming the porous matrix 19 by isotropic necking of the fine first inorganic material particles 18 such that the average particle diameter is 100 nm or less, the pore diameter (maximum pore diameter) is 100 nm or less, and further 50 nm or less. Such fine pores 15 can be formed in the ceramic porous body 16. For example, by using a ceramic porous body 16 having fine pores 15 having a pore diameter of 50 nm or less as the water vapor separator 12, a wet seal can be formed even in a low humidity environment where the relative humidity is less than 60%. Water can be efficiently moved from the dehumidifying chamber 9 to the decompression chamber 10 through the steam separator 12 thus made, and a practical dehumidifying rate can be obtained in a low humidity environment.

  However, when the ceramic porous body 16 is formed using only the first inorganic material powder (the aggregate of the first inorganic material particles 18) having an average particle diameter of 100 nm or less, the first powder as the raw material powder is used. From the average particle size of the material powder, the pore diameter of the ceramic porous body (porous sintered body) that is agglomerated in the formation process of the inorganic material powder and in the previous process and obtained by the firing process It is difficult to obtain a hole diameter as expected, for example, such that the maximum hole diameter is 100 nm or less. Therefore, in the ceramic porous body 16 of the embodiment, the maximum particle diameter of the first inorganic material particles 18 is within the porous matrix 19 formed by isotropic necking of the first inorganic material particles 18. Further, the second inorganic material particles 20 having an average particle diameter three times or more are irregularly arranged. By disposing the second inorganic material particles 20 having a large particle diameter in the porous matrix 19, the secondary particles (aggregated particles) of the first inorganic material particles 18 are crushed in the manufacturing process of the ceramic porous body 16. There is expected. Therefore, the ceramic porous body 16 provided with the pores 15 having a pore diameter of 100 nm or less, which is expected from the average particle diameter of the material powder, can be obtained.

  In order to obtain the pores 15 having a pore size corresponding to the average particle size of the first inorganic material particles 18, the second inorganic material having an average particle size three times or more than the maximum particle size of the first inorganic material particles 18. The material particles 20 are arranged in the porous matrix 19. When the average particle size of the second inorganic material particles 20 is less than three times the maximum particle size of the first inorganic material particles 18, the secondary particles can be sufficiently crushed by the second inorganic material particles 20. Can't get. For this reason, large pores are likely to be generated in the ceramic porous body 16, and the dehumidifying performance such as the dehumidifying speed is likely to be lowered in a low humidity environment. The average particle size of the second inorganic material particles 20 is more preferably 5 times or more than the maximum particle size of the first inorganic material particles 18.

  Furthermore, in the ceramic porous body 16 of the embodiment, the ratio (V2 / V1 × 100 [%]) of the volume (V2) of the second inorganic material particles 20 to the volume (V1) of the first inorganic material particles 18. Is in the range of 0.001 to 10% by volume. When the volume ratio (V2 / V1) of the second inorganic material particles 20 is less than 0.001% by volume, the effect of crushing secondary particles cannot be sufficiently obtained. For this reason, large pores are easily generated in the ceramic porous body 16. When the volume ratio (V2 / V1) of the second inorganic material particles 20 exceeds 10% by volume, large pores are likely to be generated based on the second inorganic material particles 20 having a large particle size. In any case, the dehumidifying performance such as the dehumidifying speed is reduced in a low humidity environment. The volume ratio (V2 / V1) of the second inorganic material particles 20 is more preferably in the range of 0.001 to 1% by volume.

  Although the manufacturing method of the ceramic porous body 16 is not specifically limited, For example, the manufacturing method as shown below is applied. For example, in the range of 0.001 to 10 volume%, the second inorganic material powder that is the raw material of the second inorganic material particle 20 is added to the first inorganic material powder that is the raw material of the first inorganic material particle 18. Added. These are mixed according to a normal ceramic synthesis process, for example, using a mortar or ball mill. After the binder powder is added to the mixed powder thus obtained and molded into a desired shape, the intended ceramic porous body 16 is produced by performing a degreasing process and a firing process. The ceramic porous body 16 may contain inorganic fibers such as rock wool, ceramic wool, and glass wool.

  The first inorganic material powder preferably has an average particle size that is about three times the target pore size. Further, the second inorganic material powder preferably has an average particle size of 3 times or more than the maximum particle size of the first inorganic material powder, but is not limited to this, and the average particle size distribution shows an average value. If the particle size peak is sufficiently deviated, the ceramic porous body 16 as described above can be obtained. The ceramic porous body 16 produced in this manner is isotropic, and the first inorganic material particles 18 have a porous matrix 19 formed by necking the first inorganic material particles 18. A structure in which the second inorganic material particles 20 having a sufficiently large particle diameter are irregularly arranged and the volume ratio (V2 / V1) of the second inorganic material particles 20 is in the range of 0.001 to 10% by volume. Can be obtained.

  The particle diameters and volume ratios of the first and second inorganic material particles 18 and 20 indicate values obtained as follows. The particle diameters of the inorganic material particles 18 and 20 in the ceramic porous body 16 are obtained by the following method. First, the cross section of the ceramic porous body to be evaluated is observed with a scanning electron microscope (SEM) to obtain a plurality of appropriate SEM images. At this time, the field of view to be selected is not intentional and is selected at random. In addition, it is preferable to obtain as many field-of-view images (SEM images) as possible, and it is preferable to obtain an SEM image of at least three fields of view, although it depends on the particle diameter and addition amount of the second inorganic material particles 20. .

The sizes of the first and second inorganic material particles 18 and 20 in the obtained SEM image are determined. In order to evaluate the particle size of the first inorganic material particles 18 on the SEM image, the intercept method is generally known. However, since there are many voids in the porous body, this method can be applied as it is. Can not. Therefore, the following method is applied. As shown in FIG. 4, a straight line X having a length l is drawn in the image, and the length of the straight line X overlapping the first inorganic material particles 18 is set to l ₁ , l ₂ ,. and _n. The average length L of each particle is L = (l ₁ + l ₂ +... L _n ) / n, and the particle diameter D ₁ of the first inorganic material particle 18 is calculated as D ₁ = kL (k is a constant). To do. When the particle shape is a spherical diameter, k = 1.5. Even if it is a complicated particle shape, if it is a sintered body, it is approximated as a sphere and calculation is performed. The average value of the particle diameter D ₁ of the particles obtained on the plurality of images in this way is defined as the average particle diameter D _{1ave of} the first inorganic material particles 18. In addition, among the particle diameters of the first inorganic material particles 18 measured from a plurality of SEM images, the maximum particle diameter is regarded as the maximum particle diameter D _1max of the first inorganic material particles 18.

For the second inorganic material particle 20, a particle having a particle size _{equal to} or larger than three times the maximum particle diameter D _1max (3D _1max ) of the first inorganic material particle 18 is regarded as the second inorganic material particle 20. Since the number of the second inorganic material particles 20 is extremely smaller than the number of the first inorganic material particles 18 on the image, the above-described method cannot be applied. For the second inorganic material particles 20, the average length of the maximum and minimum lengths of the particles is determined on the image, and a value obtained by multiplying this by 1.2 is the particle diameter D ₂ of the second inorganic material particles 20. To do. Determined particle diameter D ₂ of the plurality of second inorganic material particles 20 on a plurality of images and their mean value as the average particle diameter D _2Ave of the second inorganic material particles 20.

The volume ratio of the first and second inorganic material particles 18 and 20 is determined as follows. First, a field of view in which a plurality of second inorganic material particles 20 can be observed is selected, and the entire area S of the SEM image is obtained. Next, the porosity of the porous body is obtained. The porosity may be obtained from dimensions and mass, or may be obtained by a mercury intrusion method. The porosity obtained in this way is defined as p. Since the volume porosity of the isotropic porous body is equal to the area porosity, this value is also applied to the area porosity. Next, an area S ₁ as a projected image of the particles is obtained on the screen. The addition of the second inorganic material particles 20 hardly affects the porosity. Next, the average area S2 of the _second inorganic material particles 20 is determined as the area of a circle from the average particle diameter _D2ave . When the number of the second inorganic material particles 20 on the image is m, mS ₂ is the projected area occupied by the second inorganic material particles 20. As a result, it can be calculated as S ₁ = (1−p) (S−mS ₂ ). The first area S ₁ and the second area S ₂ are projected areas of the first inorganic material particles 18 and the second inorganic material particles 20, respectively. Similar to the porosity, the volume ratio is calculated using S ₁ and S ₂ on the assumption that the volume ratio is equal to the projected area ratio. In other words, volume V1 of the first inorganic material particles 18, when the volume V2 of the second inorganic material particles 20, volume fraction of the second inorganic material particles 20, the V1 / V2 ₌ S 1 / _{S 2} Become. Thus, an average volume ratio is obtained from the average values of S ₁ and S ₂ obtained from a plurality of images.

  When forming a wet seal on the water vapor separator 12, the water vapor separator 12 may include a water-soluble moisture absorbent 17 present in the pores 15 of the ceramic porous body 16, as shown in FIG. Since the water-soluble moisture absorbent 17 absorbs and retains moisture, it becomes easy to form a wet seal on the water vapor separator 12. As the water-soluble hygroscopic agent 17, citrates, carbonates, phosphates, halide salts, oxide salts, hydroxide salts, sulfates of Group 1 elements and Group 2 elements are used. These compounds may be used alone or in combination. In FIG. 2, the water-soluble moisture absorbent 17 is shown as segregated in the pores 15, but the form of the water-soluble moisture absorbent 17 is not limited to this. The water-soluble hygroscopic agent 17 may be thinly and uniformly attached to the entire inner wall or a part of the pore 15.

Specific examples of the water-soluble moisture absorbent 17 include calcium chloride (CaCl ₂ ), lithium chloride (LiCl), sodium chloride (NaCl), potassium chloride (KCl), lithium bromide (LiBr), sodium bromide (NaBr), Potassium bromide (KBr), lithium iodide (LiI), sodium iodide (NaI), potassium iodide (KI), calcium oxide (CaO), sodium oxide (Na ₂ O), potassium oxide (K ₂ O), Calcium hydroxide (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), Li Sodium acid _(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 )), sodium sulfate (Na ₂ SO ₄ ), potassium sulfate (K ₂ SO ₄ ), lithium sulfate (Li ₂ SO ₄ ), and the like, and hydrates thereof.

  Although the manufacturing method of the water vapor separator 12 is not particularly limited, for example, it is produced as follows. When the water vapor separator 12 does not include the water-soluble moisture absorbent 17, the ceramic porous body 16 produced by the method described above is used as the water vapor separator 12. When the water vapor separator 12 includes the water-soluble hygroscopic agent 17, the ceramic porous body 16 produced by the above-described method is impregnated with an aqueous solution obtained by dissolving the water-soluble hygroscopic agent 17 in water and then dried. A water vapor separator 12 is obtained. The reason for drying is that it is convenient for handling, and it is not necessary to dry it. The steam separator 12 may contain moisture from the beginning. After mixing the water-soluble moisture absorbent 17 with the raw material powder of the ceramic porous body 16, it may be molded and sintered.

  As shown in FIG. 5, the water vapor separator 12 used in the dehumidifying device 1 may be supported by a support 21 that transmits gas. FIG. 5 shows a state in which the pair of supports 21 are arranged along both surfaces of the water vapor separator 12, but the support 20 may be arranged along only one surface of the water vapor separator 12. For the support 21, a porous body having open pores, a punching material, a mesh material, or the like made of a ceramic material, a metal material, a carbon material, an organic material, or a composite material thereof is used. Specific examples of such a support 21 include paper, a porous polyimide body, a punching metal, and the like. The support 21 preferably has a through hole with a diameter of several μm or more, but is not limited thereto.

  In the dehumidifying apparatus 1 of the embodiment, the water vapor separator 12 contains water at least when the dehumidifying apparatus 1 is operated. Air in the space Rx to be dehumidified is sent into the dehumidifying chamber 9 of the dehumidifying module 2 by the blower 3. Simultaneously with the blower 3, the decompression pump 4 is operated to decompress the interior of the decompression chamber 10, thereby creating a difference between the pressure in the dehumidification chamber 9 and the pressure in the decompression chamber 10. Due to this pressure difference, the water vapor pressure in the decompression chamber 10 (water vapor pressure in the second space S2) becomes smaller than the water vapor pressure in the dehumidification chamber 9 (water vapor pressure in the first space S1). Due to the water vapor pressure difference and the water present in the water vapor separator 12, the movement of water vapor (water) occurs between the dehumidifying chamber 9 and the decompression chamber 10 disposed via the water vapor separator 12.

  When moving water vapor (water) through the water vapor separator 12, the pressure inside the decompression chamber 10 is reduced by the decompression pump 4 so that the pressure inside the decompression chamber 10 becomes −50 kPa or less with respect to the pressure inside the dehumidification chamber 9. It is preferable to do. In other words, it is preferable to depressurize the decompression chamber 10 so that the difference between the pressure in the dehumidification chamber 9 and the pressure in the decompression chamber 10 is 50 kPa or more. If this pressure difference is less than 50 kPa, the movement of water vapor (moisture) from the dehumidification chamber 9 to the decompression chamber 10 may not be sufficiently promoted. Furthermore, the pressure difference between the dehumidifying chamber 9 and the decompression chamber 10 is preferably less than 100 kPa. If the pressure difference is too large, the ceramic porous body 16 constituting the water vapor separator 12 may be damaged. The pressure difference between the dehumidifying chamber 9 and the decompression chamber 10 is more preferably in the range of 80 to 90 kPa,

  In the dehumidifying apparatus 1 shown in FIG. 1, a water vapor pressure difference is generated between the dehumidifying chamber 9 and the decompression chamber 10 by the decompression pump 4 that decompresses the interior of the decompression chamber 10. Is not something For example, dry air or heated air may be introduced into the decompression chamber 10 (second space S2). Also by these, a water vapor pressure difference can be generated between the dehumidifying chamber 9 and the decompression chamber 10. In the dehumidifying apparatus 1 shown in FIG. 1, the water vapor pressure adjusting unit that generates a water vapor pressure difference between the dehumidifying chamber 9 and the decompression chamber 10 is not particularly limited, and various types of components that can generate the water vapor pressure difference are not limited. Mechanisms can be applied.

  Water vapor (moisture) contained in the air in the dehumidification chamber 9 having a relatively high water vapor pressure is absorbed by the wet seal in the water vapor separator 12. When the water vapor separator 12 has the water-soluble moisture absorbent 17, the water vapor (water) is absorbed by the water-soluble moisture absorbent 17. Water in the water vapor separator 12 permeates into the decompression chamber 10 having a relatively low water vapor pressure. Depending on the balance of the water vapor pressure in the dehumidifying chamber 9, the water vapor pressure in the decompression chamber 10, the amount of water in the water vapor separator 12, etc., the moisture contained in the air in the dehumidifying chamber 9 is absorbed and separated by the water vapor separator 12. Release of moisture in the body 12 into the decompression chamber 10 occurs continuously. Therefore, it is possible to dehumidify by reducing the amount of moisture in the air sent from the space Rx into the dehumidifying chamber 9. The dehumidified air is returned to the space Rx. Moisture permeated into the decompression chamber 10 is discharged to the outside through the pipe 8 and the decompression pump 4. The moisture permeated into the decompression chamber 10 may be sent to a third space such as a room that needs to be humidified. The water vapor separator 12 of the embodiment can also be used in an apparatus that serves both as dehumidification and humidification.

  In the dehumidifying device 1 of the embodiment, since the water vapor separator 12 forms a wet seal, only the moisture contained in the air in the dehumidifying chamber 9 can be moved into the decompression chamber 10. That is, between the dehumidifying chamber 9 and the decompression chamber 10, basically only the moisture in the air is moved, and the dry air in the air hardly moves. Therefore, the temperature of the space Rx to be dehumidified is hardly changed. By dehumidifying the inside of the space Rx with almost no change in the temperature of the space Rx, for example, when used together with cooling of the space Rx, there is no possibility of reducing the thermal efficiency. The thermal efficiency at the time of using the dehumidifier 1 together with cooling can be improved.

  Further, in the dehumidifying apparatus 1 of the embodiment, the inside of the porous matrix 19 configured by isotropic necking of the plurality of first inorganic material particles 18 to the ceramic porous body 16 used for the water vapor separator 12. In addition, since the structure in which the second inorganic material particles 20 are irregularly arranged is applied, fine pores 15 having a pore diameter of, for example, a maximum pore diameter of 100 nm or less are stably formed in the ceramic porous body 16. Can exist. By using the ceramic porous body 16 having such fine pores 15 as the water vapor separator 12, water vapor separation in which a wet seal is formed even in a low humidity environment where the relative humidity is less than 60%. Water can be efficiently moved from the dehumidifying chamber 9 to the decompression chamber 10 via the body 12, and this makes it possible to obtain a practical dehumidifying rate in a low humidity environment.

  The structure of the dehumidifying device 1 of the embodiment is not limited to the structure shown in FIG. Although the first space S1 is set in the dehumidifying chamber 9 of the dehumidifying module 2 in FIG. 1, the first space S1 is not limited to this. As shown in FIG. 6, the first space S1 may be the space Rx itself to be dehumidified. That is, you may arrange | position the decompression chamber 10 used as 2nd space S2 via the space Rx used as 1st space S1, and the water vapor | steam separator 12. FIG. In this case, by reducing the pressure in the decompression chamber 10, water vapor (water) is directly removed from the air in the space Rx (first space S1) to be dehumidified. The settings of the first space S1 and the second space S2 can be variously changed.

  The dehumidifying speed V indicates a value measured as follows. First, a space Rx is provided by a 1 L container having a hole with a diameter of 10 mm in a constant temperature and humidity chamber in which humidity and temperature are kept constant. In such a structure, the dehumidifying module 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 from a specific relative humidity to 10% lower relative humidity. The time when this is done is the value converted into the area of the water vapor separator. The measurement temperature is 40 ° C., and the effective area of the water vapor separator is 10 mm in diameter. For example, if the time when the relative humidity is reduced from 40% to 30% is 1 hour, the dehumidification rate V is 10% / h.

  Next, examples and evaluation results thereof will be described.

Example 1
0.05% by volume of Al ₂ O ₃ powder ( _second particle) having an average particle diameter of 180 nm is added to Al ₂ O ₃ powder (first particle) having an average particle diameter of 14 nm, and the concentration is 5%. After adding an acetone solution of polyvinyl butyral (PVB), mixing in a mortar, filling in a mold, molding at a pressure of 1 t / cm ² , and further sintering at 1000 ° C., 1 mm thick ceramic porous A mass was produced. When the pore shape and the like of the porous ceramic body were measured by a mercury intrusion method, the pore diameter was approximately 3 to 30 nm, and the average pore diameter was 11 nm. The volume porosity of the ceramic porous body was 48%. Furthermore, when the shape of the 1st particle | grains which comprise a ceramic porous body was measured in accordance with the method mentioned above, the average particle diameter was 30 nm and the maximum particle diameter was 50 nm. The average particle diameter of the second particles was 200 nm.

The above-mentioned ceramic porous body was impregnated with a saturated aqueous solution of CaCl ₂ and dried to obtain a target water vapor separator. When the dehumidification rate V of the water vapor separator was measured under the conditions described above, the dehumidification rate V at a relative humidity of 40% was 10% / h. Moreover, the temperature of the dehumidification object space at the time of a dehumidification test was stable in the range of 40 degreeC +/- 1 degreeC. Furthermore, no change was observed even after the same measurement after one month.

(Example 2)
A high-purity (purity: 99.99%) Al ₂ O ₃ powder (first particle) with an average particle size of 30 nm is added to an Al ₂ O ₃ powder ( _second particle) with an average particle size of 180 nm. By adding 1% by volume, adding an acetone solution of PVB at a concentration of 5%, mixing in a mortar, filling the mold, molding at a pressure of 1 t / cm ² , and further sintering at 1000 ° C. A porous ceramic body having a thickness of 1 mm was produced. When the pore shape and the like of the ceramic porous body were measured by a mercury intrusion method, the pore diameter was 5 to 120 nm and the average pore diameter was 18 nm. The volume porosity of the ceramic porous body was 46%. Furthermore, when the shape of the 1st particle | grains which comprise a ceramic porous body was measured in accordance with the method mentioned above, the average particle diameter was 60 nm and the maximum particle diameter was 70 nm. The average particle diameter of the second particles was 200 nm.

The above-mentioned ceramic porous body was impregnated with a saturated aqueous solution of CaCl ₂ and dried to obtain a target water vapor separator. When the dehumidification rate V of the water vapor separator was measured under the conditions described above, the dehumidification rate V at a relative humidity of 40% was 8% / h. Moreover, the temperature of the dehumidification object space at the time of a dehumidification test was stable in the range of 40 degreeC +/- 1 degreeC. Furthermore, no change was observed even after the same measurement after one month.

(Example 3)
Average particle size of 60nm high purity (purity: 99.99%) to _Al 2 _{O 3} powder (the first particles), _Al 2 _{O 3} powder having an average particle diameter of 1.5μm (the second particles) After adding 0.03% by volume and further adding an acetone solution of polyvinyl butyral (PVB) having a concentration of 5%, mixing in a mortar, filling in a mold and molding at a pressure of 1 t / cm ² , further 1000 ° C. A ceramic porous body having a thickness of 1 mm was produced by sintering with 1. When the pore shape and the like of the ceramic porous body were measured by a mercury intrusion method, the pore diameter was approximately 4 to 40 nm, and the average pore diameter was 13 nm. The volume porosity of the ceramic porous body was 59%. Furthermore, when the shape of the 1st particle | grains which comprise a ceramic porous body was measured in accordance with the method mentioned above, the average particle diameter was 65 nm and the maximum particle diameter was 75 nm. The average particle size of the second particles was 1.5 μm.

The above-mentioned ceramic porous body was impregnated with a saturated aqueous solution of CaCl ₂ and dried to obtain a target water vapor separator. When the dehumidification rate V of the water vapor separator was measured under the above-described conditions, the dehumidification rate V at a relative humidity of 40% was 12% / h. Moreover, the temperature of the dehumidification object space at the time of a dehumidification test was stable in the range of 40 degreeC +/- 1 degreeC. Furthermore, no change was observed even after the same measurement after one month.

(Comparative Example 1)
A porous ceramic body was produced under the same conditions as in Example 1 except that Al ₂ O ₃ powder (second particles) having an average particle diameter of 180 nm was not added. The volume porosity of the ceramic porous body was about the same as in Example 1, but the pore diameters varied, and many pores with a pore diameter of about 100 nm were observed in addition to the pores with a pore diameter of about 11 nm. This ceramic porous body was impregnated with a saturated aqueous solution of CaCl ₂ and dried to obtain a target water vapor separator. When the dehumidification rate V of the water vapor separator was measured under the conditions described above, the dehumidification rate V at a relative humidity of 40% was 1% / h.

(Comparative Example 2)
A porous ceramic body was produced under the same conditions as in Example 2 except that Al ₂ O ₃ powder (second particles) having an average particle diameter of 180 nm was not added. The volume porosity of the ceramic porous body was about the same as in Example 2, but the pore diameters varied, and many pores with a pore diameter of about 27 nm were observed in addition to the pores with a pore diameter of about 18 nm. This ceramic porous body was impregnated with a saturated aqueous solution of CaCl ₂ and dried to obtain a target water vapor separator. When the dehumidification rate V of the water vapor separator was measured under the conditions described above, the dehumidification rate V at a relative humidity of 40% was 3% / h.

(Comparative Example 3)
A porous ceramic body was produced under the same conditions as in Example 3 except that Al ₂ O ₃ powder (second particles) having an average particle diameter of 1.5 μm was not added. The volume porosity of the ceramic porous body was about the same as in Example 3, but the pore diameters varied, and many pores with a pore diameter of about 30 nm were observed in addition to the pores with a pore diameter of about 13 nm. This ceramic porous body was impregnated with a saturated aqueous solution of CaCl ₂ and dried to obtain a target water vapor separator. When the dehumidification rate V of the water vapor separator was measured under the conditions described above, the dehumidification rate V at a relative humidity of 40% was 5% / h.

(Comparative Example 4)
After adding an acetone solution of polyvinyl butyral (PVB) having a concentration of 5% to Al ₂ O ₃ powder having an average particle diameter of 180 nm, mixing in a mortar, filling the mold and molding at a pressure of 1 t / cm ^2. Further, by sintering at 1000 ° C., a ceramic porous body having a thickness of 1 mm was produced. When the pore shape and the like of the ceramic porous body were measured by a mercury intrusion method, the pore diameter was approximately 40 to 170 nm and the average pore diameter was 70 nm. The volume porosity of the ceramic porous body was 42%. This ceramic porous body was impregnated with a saturated aqueous solution of CaCl ₂ and dried to obtain a target water vapor separator. When the dehumidification rate V of the water vapor separator was measured under the conditions described above, the dehumidification rate V at a relative humidity of 40% was 0% / h.

  In addition, although several embodiment of this invention was described, these embodiment is shown as an example and is not intending limiting the range of invention. These novel embodiments can be implemented in various other 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 gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  DESCRIPTION OF SYMBOLS 1 ... Humidity adjustment (dehumidification) apparatus, 2 ... Dehumidification module, 3 ... Blower, 4 ... Depressurization pump, 9 ... Dehumidification chamber, 10 ... Decompression chamber, 11 ... Connection path, 12 ... Water vapor separator, 15 ... Fine pore, 16 DESCRIPTION OF SYMBOLS ... Ceramic porous body, 17 ... Water-soluble hygroscopic material, 18 ... 1st inorganic material particle, 19 ... Porous matrix, 20 ... 2nd inorganic material particle, S1 ... 1st space, S2 ... 2nd space .

Claims (10)

A porous matrix constituted by isotropic necking of a plurality of first inorganic material particles;
Second inorganic material particles that are irregularly arranged in the porous matrix and have an average particle size of three times or more than the maximum particle size of the first inorganic material particles;
The ceramic porous body, wherein the volume ratio of the second inorganic material particles is 0.001% by volume or more and 10% by volume or less of the volume of the first inorganic material particles. It exists between the 1st space and the 2nd space, and exists in the 1st space by making the water vapor pressure in the 2nd space lower than the water vapor pressure in the 1st space. A water vapor separator that allows water vapor to pass through the second space;
Comprising a ceramic porous body having a first surface, a second surface facing the first surface, and pores extending from the first surface to the second surface;
The ceramic porous body includes a porous matrix configured by isotropic necking of a plurality of first inorganic material particles, and the first inorganic material is irregularly disposed in the porous matrix. Second inorganic material particles having an average particle diameter of 3 times or more than the maximum particle diameter of the particles, and the volume ratio of the second inorganic material particles is 0.001 volume of the volume of the first inorganic material particles. % To 10% by volume or less.   The water vapor separator according to claim 2, further comprising a water-soluble hygroscopic material present in the pores of the ceramic porous body.   The water vapor separator according to claim 2 or 3, further comprising water retained in the pores of the ceramic porous body.   The water vapor separator according to any one of claims 2 to 4, wherein an average particle diameter of the first inorganic material particles is 100 nm or less.   The water vapor separator according to any one of claims 2 to 5, wherein an average pore diameter of the pores existing in the ceramic porous body is 0.5 nm or more and 50 nm or less.   The water vapor separator according to any one of claims 2 to 6, wherein a volume porosity of the ceramic porous body is 10% or more and 80% or less.   The first and second inorganic material particles are each independently an oxide, nitride, or carbide of aluminum, silicon, zinc, magnesium, calcium, barium, nickel, cobalt, iron, chromium, titanium, zirconium, or copper. The water vapor separator according to any one of claims 2 to 7, comprising at least one selected from the group consisting of silicate and silicate. A first space;
A second space leading to the first space;
The first surface is exposed to the first space, and the second surface is exposed to the second space, and the first space and the second space are partitioned. The steam separator according to any one of claims 2 to 8, which is provided,
A water vapor pressure adjusting unit that adjusts the water vapor pressure in the second space such that the water vapor pressure in the second space is lower than the water vapor pressure in the first space;
A humidity control apparatus that allows water vapor existing in the first space to pass through the second space through the water vapor separator.   The humidity control apparatus according to claim 9, wherein the water vapor pressure adjustment unit includes a pressure adjustment mechanism that reduces the pressure in the second space from the pressure in the first space.

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