JP2017177055A - Monolith-type substrate and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a monolith-type substrate that can provide compactification and/or reduction in weight thereof while maintaining permeability and can improve grinding workability, and to provide a method for manufacturing the same.SOLUTION: A monolith-type substrate 10 is constituted of an aggregate and a binding material and has pores. The monolith-type substrate 10 includes a plurality of filtration cells 24, a plurality of water collection cells 25 and a discharge flow passage 26. The aggregate has D50 of 5 μm or more and less than 40 μm. A volume ratio of the binding material relative to a total volume of the aggregate and the binding material is 15 vol.% or more and 35 vol.% or less.SELECTED DRAWING: Figure 8

Description

  The present invention relates to a monolith type substrate and a method for producing the same.

  Conventionally, in a monolith type separation membrane structure comprising a monolith type substrate having a plurality of cells, an intermediate layer formed on the inner surface of each cell, and a separation membrane formed on the inner surface of the intermediate layer, the intermediate layer Has been proposed that suppresses the strength reduction of the monolithic separation membrane structure after high-temperature alkali treatment by defining the mutual relationship between the thickness of the substrate and the partition wall thickness of the base material between the two cells (see Patent Document 1). ). In Patent Document 1, the thickness of the intermediate layer is preferably from 100 μm to 500 μm, and the partition wall thickness of the substrate is preferably from 0.51 mm to 1.55 mm.

  In Patent Document 2, the thickness of the partition wall is preferably 0.2 mm or more in order to prevent the monolithic base material from being greatly deformed and closed by the firing at the time of manufacturing.

  In addition, for the purpose of improving the strength of the monolithic base material and increasing the fluid permeation amount, the 50% particle diameter (D50) of the aggregate particles contained in the main body is adjusted to 40 μm to 100 μm and the aspect ratio of the aggregate particles is adjusted. A technique has been proposed (see Patent Document 3).

International Publication No. 2012/128218 Japanese Patent No. 5599785 Japanese Patent Laid-Open No. 2001-340718

  However, depending on the use of the monolith type separation membrane structure, it may be desired to further reduce the size and / or weight of the monolithic substrate. In addition, if the partition wall thickness is reduced for compactness and / or weight reduction, if it is necessary to grind the main body, it becomes easier to deform during firing if a notch or the like is added to the molded body before firing. However, there is a problem that not only the grinding tool is consumed quickly but also the grinding time is increased.

  The present invention has been made in view of the above-described circumstances, and provides a monolithic base material that can be reduced in size and / or weight while maintaining permeation performance, and that can improve grinding workability, and a method for manufacturing the same. The purpose is to do.

The monolith type substrate according to the present invention is composed of an aggregate and a binder and has pores. The monolithic substrate includes a plurality of filtration cells that are continuous from the first end surface to the second end surface, a plurality of water collection cells that are continuous from the first end surface to the second end surface, and are sealed at both ends, and a plurality of water collection cells. And a discharge channel penetrating the water cell. The partition wall thickness of the shortest portion between two adjacent filtration cells among the plurality of filtration cells is 0.05 mm or more and less than 0.2 mm. The D _g 50 of the aggregate is 5 μm or more and less than 40 μm. The volume ratio of the binder to the total volume of the aggregate and the binder is 15% by volume to 35% by volume.

  ADVANTAGE OF THE INVENTION According to this invention, the monolith type | mold base material which can be reduced in size and / or weight, maintaining the permeation | transmission performance, and can improve grinding workability, and its manufacturing method can be provided.

Perspective view of monolithic separation membrane structure Plan view of first end face of monolith type separation membrane structure AA sectional view of FIG. The figure for demonstrating the slit formation method in a monolith type base material The figure for demonstrating the slit formation method in a monolith type base material Cross-sectional SEM image of monolithic substrate according to Comparative Example 1 Cross-sectional SEM image of monolithic substrate according to Comparative Example 3 Cross-sectional SEM image of monolithic substrate according to Example 1 Graph showing an example of particle size distribution (with / without classification) of aggregate powder Graph showing the pore size distribution of Examples 1, 4, 5 and Comparative Example 3

  Next, embodiments of the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, the drawings are schematic, and the ratio of each dimension may be different from the actual one. Accordingly, specific dimensions and the like should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

  In the following description, “monolith” means a shape having a plurality of through-holes formed in the longitudinal direction, and is a concept including a honeycomb.

(Configuration of monolith type separation membrane structure 100)
FIG. 1 is a perspective view of a monolith type separation membrane structure 100. FIG. 2 is a plan view of the first end face 11S. FIG. 3 is a cross-sectional view taken along the line AA of FIG.

(Structure overview)
The monolith type separation membrane structure 100 shown in FIGS. 1 to 3 includes a monolithic base material 10 made of a ceramic porous body and having both end faces 11S and 11T and an outer peripheral face 11U. The monolithic substrate 10 has a cylindrical shape, and has a plurality of filtration cells 24 that are formed in a row from one end surface 11S to the other end surface 11T (in a generally horizontal direction in FIG. 1), And a plurality of water collecting cells 25 formed in a row from one end surface 11S to the other end surface 11T (in a generally horizontal direction in FIG. 1).

  In the monolith type separation membrane structure 100, the cross-sectional shapes of the filtration cell 24 and the water collection cell 25 are circular. And although the filtration cell 24 is open to both end surfaces, the water collection cell 25 is sealed with the plugging portions 12 and 13 at the both end surfaces so that the water collection cell 25 communicates with the external space. In addition, a discharge channel 26 is provided. An intermediate layer 20 and a separation membrane 30 are disposed on the inner wall surface of the filtration cell 24 having a circular cross-sectional shape.

  In the monolith type separation membrane structure 100, the discharge flow path 26 is provided in the vicinity of both end faces 11S, 11T for each of the plurality of water collection cell 25 rows (hereinafter referred to as “water collection cell rows”) 25L. One is formed. In the monolith type separation membrane structure 100, there are five water collection cell rows 25L, and the discharge flow path 26 allows a plurality of water collection cells 25 to communicate with each other and the outer periphery of the monolith type base material 10 It opens to the surface 11U.

  In FIGS. 1 to 3, since there are five water collection cell rows 25L in the monolithic separation membrane structure 100, the number of the discharge channels 26 in the monolithic separation membrane structure 100 is 10 in total at both ends. .

  By setting it as the above structures, the component which permeate | transmitted the mixed fluid (liquid mixture and gas mixture) which flows in into the filtration cell 24, and the filtration cell 24 can be isolate | separated efficiently. Specifically, the permeated component that has permeated through the separation membrane 30 on the inner surface of the filtration cell 24 permeates through the intermediate layer 20 and then sequentially passes through the porous body constituting the inside of the partition wall of the monolithic substrate 10 to be removed. Although it is discharged | emitted from the wall surface 11U, it is necessary to permeate | transmit the inside of a partition (porous body) over long distance, so that the filtration cell 24 of the inner side may be more. Here, by providing the water collection cell 25 and the discharge flow path 26, it passes easily through the partition wall between the filtration cells 24, and easily passes through the water collection cell 25 and the discharge flow path 26 with little pressure loss. It is possible to discharge to the outside.

  In the monolith type separation membrane structure 100, the mixed fluid flows directly from the porous body portions of the both end faces 11 </ b> S and 11 </ b> T of the monolith type base material 10 and is separated by the separation membrane 30 formed on the inner wall surface of the predetermined filtration cell 24. In order to prevent the mixed fluid from flowing out, the sealing portions 14 and 15 are provided so as to cover the porous bodies on both end surfaces 11S and 11T of the monolithic substrate 10 into which the mixed fluid flows. Note that both end surfaces of the filtration cell 24 provided with the separation membrane 30 are continuous with the seal portions 14 and 15 and open. An intermediate layer 20 and a separation membrane 30 are sequentially formed on the inner surface of each filtration cell 24.

(Configuration of each structure)
The monolith type substrate 10 is formed in a cylindrical shape. The length of the monolithic base material 10 in the longitudinal direction can be set to 100 to 2000 mm. The diameter of the monolithic substrate 10 can be 30 to 220 mm. The monolithic substrate 10 may be an elliptical column or a polygonal column.

  The partition wall thickness D1 that does not include the intermediate layer 20 and the separation membrane 30 in the shortest portion between two adjacent filtration cells 24 is 0.05 mm or more and less than 0.2 mm. By setting the partition wall thickness D1 between the two filtration cells 24 to less than 0.2 mm, the filtration cells 24 can be densified and the total surface area of the separation membrane 30 can be increased. By setting the partition wall thickness D1 between the two filtration cells 24 to be 0.05 mm or more, it is possible to suppress the partition structure from collapsing during manufacturing and / or use due to insufficient strength of the monolithic substrate 10. The partition wall thickness D1 between the two filtration cells 24 is more preferably 0.10 mm or more and 0.18 mm or less.

  In the present embodiment, the partition wall thickness D1 is unified at all locations between two adjacent filtration cells 24, but a plurality of types of partition wall thicknesses D1 may exist.

  As shown in FIG. 2, when the first end face 11S is viewed in plan, the plurality of filtration cells 24 form a plurality of filtration cell rows 24L. Each filtration cell row 24L includes two or more filtration cells 24 arranged along a short direction (an example of a predetermined direction) orthogonal to the longitudinal direction. In the present embodiment, 28 filtration cell rows 24L are formed, and 7 to 29 filtration cells 24 are arranged in each row. However, the number of filtration cell rows 24L and the filtration contained in each row are included. The number of cells 24 can be changed as appropriate.

  The partition wall thickness D3 that does not include the intermediate layer 20 and the separation membrane 30 in the shortest part of the adjacent filtration cell 24 and the water collection cell 25 is not particularly limited, and can be 0.05 mm or more and less than 0.2 mm. By making the partition wall thickness D3 less than 0.2 mm, the total surface area of the separation membrane 30 can be increased. From the viewpoint of increasing the total surface area of the separation membrane 30, the smaller the partition wall thickness D <b> 3, the higher the density of the filtration cell 24, which is good. However, if it is too small, the strength is insufficient and the monolith type is used at the time of manufacture and / or use. Since the partition wall structure of the base material 10 may collapse, it can be substantially 0.05 mm or more. From the viewpoint that the partition structure of the monolithic substrate 10 is not easily broken and the total surface area can be increased, the partition wall thickness D3 is more preferably 0.1 mm or more and 0.18 mm or less. Moreover, although not shown in figure, the space | interval of the adjacent water collection cells 25 can also be 0.05 mm or more and less than 0.2 mm, and it is more preferable that they are 0.1 mm or more and 0.18 mm or less.

  In the present embodiment, the partition wall thickness D3 is unified at all locations between the adjacent filtration cell 24 and the water collection cell 25, but a plurality of types of partition wall thickness D3 may exist.

  As shown in FIG. 2, when the first end surface 11S is viewed in plan, the plurality of water collection cells 25 form a plurality of water collection cell rows 25L. Each water collection cell row 25L includes two or more water collection cells 25 arranged in the short direction (an example of a predetermined direction). In this embodiment, five water collection cell rows 25L are arranged at positions separated from each other, and 22 to 29 water collection cells 25 are arranged in each row, but the position of the water collection cell row 25L The number of columns and the number of water collecting cells 25 included in each column can be changed as appropriate.

  As shown in FIG. 1, the discharge flow path 26 has an opening 26a that opens to the outer peripheral surface 11U. The opening 26 a may be disposed only in one of both end portions of the monolithic base material 10, and may be formed in the middle of the longitudinal direction in addition to the both end portions of the monolithic base material 10. The openings 26a are preferably disposed at least at both ends of the monolithic substrate 10 from the viewpoint that the transmitted component is discharged uniformly. The number, shape, and position of the discharge passages 26 may be the same or different in all the water collection cell rows 25L.

  The first plugging 12 and the second plugging 13 are arranged in all the water collection cells 25. The first plugging 12 and the second plugging 13 are arranged opposite to each end of each water collection cell 25. The first plugging 12 and the second plugging 13 can be made of a porous material. The filling depth of the first plugging 12 and the second plugging 13 can be about 5 to 20 mm.

  The first seal portion 14 covers the entire first end surface 11S and a part of the outer peripheral surface 11U. The first seal portion 14 suppresses the mixed fluid from infiltrating the first end surface 11S. The first seal portion 14 is formed so as not to block the inlet of the filtration cell 24. The first seal portion 14 covers the first plugging 12. Glass, metal, rubber, resin, or the like can be used as a material constituting the first seal portion 14, and glass is preferable in consideration of consistency with the thermal expansion coefficient of the monolithic substrate 10.

  The second seal portion 15 covers the entire second end surface 11T and a part of the outer peripheral surface 11U. The second seal portion 15 suppresses the mixed fluid from infiltrating the second end surface 11T. The second seal portion 15 is formed so as not to block the outlet of the filtration cell 24. The second seal portion 15 covers the second plugging 13. The second seal portion 15 can be made of the same material as the first seal portion 14.

(Monolith type substrate 10)
The monolith type base material 10 contains an aggregate and a binder.

  Examples of the aggregate include alumina, silica, mullite, zirconia, titania, yttria, silicon nitride, and silicon carbide. In particular, alumina is suitable as an aggregate because it is easy to obtain raw materials (aggregate particles) having a controlled particle size, can form a stable clay, and has high corrosion resistance.

  The binder is an inorganic component that sinters and solidifies at a temperature at which the aggregate particles do not sinter. As the binder, at least one inorganic binder among titania, mullite, easily sinterable alumina, silica, glass frit, clay mineral, and easily sinterable cordierite can be used.

The 50% diameter (hereinafter referred to as “D _g 50”) in the volume cumulative particle size distribution of the particles constituting the aggregate (hereinafter referred to as “aggregate particles”) is 5 μm or more and less than 40 μm. D _g 50 is a so-called median diameter. D _g 50 is preferably 10 μm or more and 25 μm or less, and more preferably 20 μm or less. The D _g 50 of the aggregate particles can be adjusted by the D _g 50 of the aggregate raw material powder described later. The value of D _g 50 of the aggregate particles is the same as the value of D _g 50 of the aggregate raw material.

The 10% diameter (hereinafter referred to as “D _g 10”) in the volume cumulative particle size distribution of aggregate particles is 10 ^(x−0.7) μm or more when D _g 50 is 10 ^x μm. Is preferred. Further, the 90% diameter (hereinafter referred to as “D _g 90”) in the volume cumulative particle size distribution of the aggregate particles is 10 ^{(x + 0.3)} μm or less when D _g 50 is 10 ^x μm. Is preferred. Therefore, it is preferable that D _g 10 ≧ 10 ^(x−0.7) μm and D _g 90 ≦ 10 ^{(x + 0.3)} μm be established for the aggregate particles of the monolithic substrate 10. This means that the particle size distribution of 80% of the aggregate particles falls within the range of 10 ^{((x−0.2) ± 0.5)} μm, that is, a sharp particle size distribution. . The D _g 90 and D _g 10 of the aggregate particles can be adjusted by D _g 90 and D _g 10 of the aggregate raw material powder described later. The values of D _g 90 and D _g 10 of the aggregate particles are the same as the values of D _g 90 and D _g 10 of the aggregate raw material powder.

The D _g 10 of the aggregate particles is more preferably 10 ^(x−0.2) μm or more. The D _g 90 of the aggregate particles is more preferably 10 ^{(x + 0.2)} μm or less.

  In the cross-sectional SEM image of the monolith substrate 10, the volume cumulative particle size distribution of the aggregate particles is assumed that all the aggregate particles included in the cross-sectional SEM image having an arbitrary area are circular, and the diameter is calculated from the area. It can be measured by calculating. More specifically, a cross-sectional SEM image in the range of 200 μm × 200 μm (the SEM image is preferably a higher resolution, for example, a reflected electron image taken at an acceleration voltage of 10 kV or less and a magnification of 1000 or more) 3) by image analysis, the pores, aggregates, and binders are distinguished, the area of each distinct aggregate particle is measured, and each aggregate particle is determined from a circular approximation. Can be calculated. For image analysis, for example, image analysis application software “Image-Pro Plus (trade name)” manufactured by MEDIA CYBERNETICS can be used.

  Among the aggregate particles, the average aspect ratio of aggregate particles having a particle size of 10 μm or more can be 1.5 or more and 100 or less. The average aspect ratio of aggregate particles having a particle size of 10 μm or more is preferably 2 or more.

  In the present embodiment, the particle size of the aggregate particles is the diameter of a circle having the same area as the aggregate particles. The aspect ratio is a value obtained by dividing the maximum ferret diameter by the minimum ferret diameter (maximum ferret diameter / minimum ferret diameter). The maximum ferret diameter is the maximum distance between two parallel straight lines sandwiching the aggregate particles in the cross-sectional SEM image of the monolith substrate 10. The minimum ferret diameter is the minimum distance between two parallel straight lines sandwiching the aggregate particles on the cross-sectional SEM image. The average aspect ratio of the aggregate particles is an arithmetic average value of the aspect ratios of 10 aggregate particles arbitrarily selected on the SEM image. When obtaining the average aspect ratio, if 10 aggregate particles do not exist in one cross-sectional SEM image, 10 aggregate particles may be arbitrarily selected from a plurality of cross-sectional SEM images.

  The volume ratio of the aggregate to the total volume of the aggregate and the binder in the monolith type substrate 10 can be 65% by volume or more and 85% by volume or less. The volume ratio of the aggregate is preferably 70% by volume or more and 80% by volume or less, and more preferably 75% by volume or more.

  The volume ratio of the binder to the total volume of the aggregate and the binder in the monolithic substrate 10 is 15% by volume or more and 35% by volume or less. The volume ratio of the binder is preferably 20% by volume or more and 30% by volume or less, and more preferably 25% by volume or less. The volume ratio of the binder can be calculated based on the area occupancy of the binder in the cross-sectional SEM image of the monolith substrate 10.

  The volume ratio (porosity) of pores (pores) in the monolithic substrate 10 is not particularly limited, but is preferably 20% or more and 60% or less. The porosity is more preferably 30% or more and 45% or less. The porosity can be measured by a mercury intrusion method, or can be calculated based on the area occupation ratio of the pores in the cross-sectional SEM image of the monolithic substrate 10.

The 50% diameter (hereinafter referred to as “D _p 50”) in the volume cumulative pore size distribution in the monolithic substrate 10 is not particularly limited, but is preferably 1 μm or more and 10 μm or less. The pore diameter D _p 50 is more preferably 2 μm or more and 5 μm or less. The pore diameter D _p 50 is a so-called median diameter.

The 10% diameter (hereinafter referred to as “D _p 10”) in the volume cumulative pore diameter distribution in the monolith type substrate 10 is not particularly limited, but when the pore diameter D _p 50 is 10 ^y μm, 10 ^{(y + 0. 2)} It is preferable that it is below μm. The 90% diameter (hereinafter referred to as “D _p 90”) in the volume cumulative pore diameter distribution in the monolithic substrate 10 is not particularly limited, but when the pore diameter D _p 50 is 10 ^y μm, 10 ^{(y− 0.2)} It is preferable that it is μm or more. Therefore, in the present embodiment, it is preferable that D _p 10 ≦ 10 ^{(y + 0.2)} μm and D _p 90 ≧ 10 ^(y−0.2) μm are satisfied with respect to the pore diameter of the monolithic substrate 10. . This means that the pore diameter distribution in which 80% of all pores fall within the range of 10 ^{(y ± 0.2)} μm, that is, a sharp pore diameter distribution. When the pore diameter distribution is sharp, this means that small micropores relative to D p ₅₀ or larger coarse pores, is small. Smaller pores are preferred because they do not effectively reduce the pressure loss of the fluid. On the other hand, when the intermediate layer is formed on the monolithic base material, large rough air holes are preferable because the intermediate layer slurry enters the base material and closes the base material pores.

  The volume cumulative pore size distribution in the monolithic substrate 10 can be measured by a mercury intrusion method.

(Manufacturing method of monolithic separation membrane structure 100)
First, the aggregate and the binder are weighed. At this time, in order to make the partition wall thickness less than 0.2 mm, the D _g 50 of the aggregate raw material powder is set to 5 μm or more and 40 μm or less in accordance with the die used in the extrusion molding. As described above, since the aggregate is fine and has a large specific surface area, the volume ratio of the binder is adjusted so that the connection between the aggregates is not insufficient, but if too much, the strength and wear resistance will be too high. Therefore, the amount should be as small as possible. Specifically, it is adjusted to be 15 volume% or more and 35 volume% or less. Note that by classifying the raw material powder _{aggregate, D} g 10 of when the _D g 50 and 10 ^z [mu] m is ^{10 (z-0.7) μm} or more, _{and, D} g 90 is ^{10 (z + 0.3 )} By using an aggregate powder having a sharp particle size distribution of μm or less and a relatively small specific surface area, the volume ratio of the binder can be kept relatively small.

  As a method for classifying aggregate raw material powder, wet classification or dry classification can be used. Wet classification is a technique in which raw material powder is dispersed in water and the aggregate particles of a desired size are taken out by adjusting the sedimentation rate and upward water flow of the raw material powder. Dry classification is a technique using a vibrating sieve or a turbo screener. In the method using a vibration sieve, aggregate particles having a desired size can be taken out by applying vibration to the vibration sieve and dropping aggregate particles smaller than the openings. In the method using a turbo screener, aggregate particles of a desired size can be taken out by flowing an air flow while rotating a blade provided in a cylindrical screen mesh at a high speed.

  In addition, when using an inorganic binder as a binder, the average particle diameter can be 0.1 micrometer or more and 10 micrometers or less. When the thickness is 10 μm or less, it is possible to provide a monolithic substrate 10 that is easily melted by firing and / or highly dispersed between aggregate particles and has high strength. From the viewpoint that it can be more highly dispersed among the aggregate particles, the average particle size of the inorganic binder is better to be small, but the finer the raw material, the higher the cost tends to be, so that it is substantially 0.1 μm or more. be able to.

  Next, a kneaded material is prepared by adding an organic binder such as methylcellulose, a dispersing agent and water to the weighed aggregate powder and binder and kneading them.

  Next, the prepared clay is extruded using, for example, a vacuum extrusion molding machine to obtain a monolith-shaped molded body having a plurality of filtration cells 24 and a plurality of water collecting cells 25.

  Next, the monolith type molded body is fired at, for example, 900 to 1600 ° C. to form the monolith type substrate 10. As described above, since the ratio of the binder is relatively small, the strength and / or wear resistance of the monolithic substrate can be relatively low.

  Next, as shown in FIGS. 4 and 5, a diamond cutting tool such as a band saw, a disk cutter, or a wire saw with diamond abrasive grains on each of the first end surface 11S and the second end surface 11T of the monolithic substrate 10 is used. Using, a slit for the discharge channel is formed along each water collection cell row 25L. As described above, since the strength and / or wear resistance of the monolithic substrate 10 is reduced and the aggregate particles are easily peeled off, the consumption of the diamond cutting tool can be suppressed and the processing time can be shortened. . Note that it is preferable to further reduce the friction by using a solvent such as water in order to prevent the life of the cutting tool from being shortened due to heat generated by friction between the monolithic base material 10 and the cutting tool or the degreasing of the diamond abrasive grains.

  Next, in the obtained monolith type substrate, a plugging member in a slurry state is filled in the space from the both end surfaces of the water collection cell in which the slit for the discharge channel is formed to the discharge channel 26 Thus, a monolithic base material filled with a plugging member is obtained. Specifically, a film (masking) such as polyester is attached to both end faces of the monolith substrate, and a hole is made in the film by laser irradiation or the like in a portion corresponding to the discharge channel 26.

  Next, the end face to which the film of the monolith type substrate is attached is pressed into a container filled with a plugging member (slurry), and further filled with the air cylinder or the like by pressurizing with 200 kg, for example. A monolithic substrate filled with a sealing member can be obtained. Then, the obtained plugged member-filled unfired monolithic base material is fired, for example, at 900 to 1400 ° C. to obtain a plugged member-filled monolithic base material.

  And the intermediate layer 20 used as the foundation | substrate of the separation membrane 30 is formed in the inner wall face of the filtration cell 24 of a plugging member filling monolith type base material. In order to form (deposit) the intermediate layer 20, first, an intermediate layer slurry is prepared. The intermediate layer slurry can be prepared by adding 400 parts by mass of water to 100 parts by mass of a ceramic raw material having a desired particle size (for example, an average particle size of 1 to 5 μm). In addition, an inorganic binder for a film may be added to the intermediate layer slurry in order to increase the film strength after sintering. As the inorganic binder for the film, clay, kaolin, titania sol, silica sol, glass frit and the like can be used. The addition amount of the inorganic binder for membrane is preferably 5 to 42 parts by mass from the viewpoint of membrane strength.

  Next, the intermediate layer slurry is deposited on the inner wall surface of the filtration cell 24, dried, and then sintered at, for example, 900 to 1050 ° C. to form the intermediate layer 20. The intermediate layer 20 can be formed by dividing into a plurality of layers like the intermediate layer 21 and the intermediate layer 22 by using a plurality of types of slurry having different average particle diameters. In the case where a plurality of intermediate layers 20 are formed, the film forming step and the baking step may be performed for each intermediate layer, or may be performed as a unit after repeating the plurality of film forming steps.

  Next, the glass raw material slurry is applied to the end face of the obtained monolithic substrate with an intermediate layer by spraying or brushing, and then fired at 800 to 1000 ° C., for example, so that the first and second seal portions 14 are formed. , 15 are formed. The glass raw material slurry is prepared, for example, by mixing water and an organic binder in a glass frit. The case where the material of the first and second seal portions 14 and 15 is glass has been described above. Any material may be used as long as it does not allow the discharged separation fluid to pass through. In the case where the intermediate layer 20 has a multilayer structure, the molded body of the first and second seal portions 14 and 15 may be formed during the formation of the intermediate layer 20.

  Next, the separation membrane 30 is formed on the inner surface of the intermediate layer 20. Here, when the average pore diameter of the separation membrane 30 is smaller than 1 nm and it is necessary to reduce the pressure loss in order to reduce the pressure loss, it is preferable to dispose an underlayer further between the intermediate layer 20 and the separation membrane 30. . For example, titanium isopropoxide is hydrolyzed on the intermediate layer 20 in the presence of nitric acid to obtain a titania sol solution, diluted with water to prepare an underlayer sol, and the prepared underlayer sol After flowing through the inner wall surface of a predetermined cell of the monolithic substrate with a layer, it is desirable to form a base layer by performing a heat treatment at 400 to 500 ° C., for example.

  As the separation membrane 30, a known MF (microfiltration) membrane, UF (ultrafiltration) membrane, gas separation membrane, pervaporation membrane, vapor permeable membrane, or the like can be used. Specifically, as the separation membrane 30, a ceramic membrane (see, for example, JP-A-3-267129 and JP-A-2008-246304), a carbon monoxide separation membrane (see, for example, Japanese Patent No. 4006107), helium Separation membrane (see, for example, Japanese Patent No. 395833), hydrogen separation membrane (see, for example, Japanese Patent No. 3933907), carbon membrane (see, for example, JP-A No. 2003-286018), zeolite membrane (see, for example, JP-A No. 2004) -66188), silica film (for example, see pamphlet of International Publication No. 2008/050812), organic-inorganic hybrid silica film (Japanese Patent Laid-Open No. 2013-203618), p-tolyl group-containing silica film (Japanese Patent Laid-Open No. 2013-2003). No. 226541). As a method of forming the separation membrane 30, an appropriate method according to the type of the separation membrane 30 may be used.

(Other embodiments)
As mentioned above, although one Embodiment of this invention was described, this invention is not limited to the said embodiment, A various change is possible in the range which does not deviate from the summary of invention.

  Although the monolith type separation membrane structure 100 includes the filtration cell 24 and the water collection cell 25, the monolith separation membrane structure 100 may not include the water collection cell 25. In this case, the monolithic separation membrane structure 100 may not include the discharge flow channel 26.

  Each of the first and second seal portions 14 and 15 covers a part of the outer peripheral surface 11U, but may not cover the outer peripheral surface 11U.

  Examples of the monolith type separation membrane structure according to the present invention will be described below. However, the present invention is not limited to the examples described below.

(Production of Examples 1 to 5 and Comparative Examples 1 to 4)
Monolith type separation membrane structures according to Examples 1 to 5 and Comparative Examples 1 to 4 were produced as follows.

  First, as shown in Table 1, the particle size distribution of the aggregate powder was changed for each example by classifying the aggregate raw material powder (hereinafter referred to as “aggregate powder”). The particle size distribution of the aggregate powder was measured using a laser diffraction / diffusion type particle size distribution measuring device (MT3300 EXII) manufactured by Microtrack Bell. The measurement results are shown in FIG. From FIG. 9, it can be seen that the particle size distribution is remarkably changed by classification.

  Next, the aggregate powder obtained by classification and / or the aggregate powder not classified and the binder were weighed. In Example 4, the aggregate powder obtained by classification and the aggregate powder not classified were mixed at a ratio of 50:50. At this time, by adjusting the mass ratio of the aggregate powder and the binder, the volume ratio of the aggregate and the binder was changed for each example as shown in Table 1.

  Next, a clay was prepared by adding and kneading methylcellulose, a dispersing agent and water to the aggregate powder and the binder.

  Next, the kneaded material was extrusion-molded to produce a monolith-type substrate molded body having a plurality of filtration cells and a plurality of water collection cells. At this time, by adjusting the size and position of each filtration cell and each water collection cell, as shown in Table 1, the inner diameter of the filtration cell and the partition wall thickness between the filtration cells were changed for each example.

  Next, the molded body of the monolith type substrate was fired (1250 ° C., 2 hours). The size of the fired monolithic substrate was 63 mm in diameter and 300 mm in length.

  Next, slits were made with diamond disks along the water collection cell rows on both end faces of the monolithic substrate. At this time, a large number of monolithic substrates were prepared for each example, and the number of slits and the average processing time required for one slit until the diamond disk had to be replaced were measured. Table 1 shows the results of measurement of the number of slit processing and the average processing time until replacement.

  Next, a polyester film was affixed to both end faces of the monolith substrate, and holes were formed in portions of the polyester film corresponding to the water collection cells and slits.

  Next, both ends of the main body were pressed against the plugging member in a slurry state to form a plugged molded body. And the 1st and 2nd plugging and the discharge flow path were formed by baking (1250 degreeC, 1 hour) the molded object of plugging.

Next, 14 parts by mass of an inorganic binder is added to 100 parts by mass of alumina particles (aggregate) having an average particle size of 2.3 μm, and water, a dispersing agent, and a thickener are further added and mixed. A slurry for one intermediate layer was prepared. Using the slurry, the first intermediate layer slurry was adhered to the inner peripheral surface of the filtration cell through-hole by the filtration film forming method described in Japanese Patent Publication No. 63-66566. Then, the 1st intermediate | middle layer was formed by baking with an electric furnace (950 degreeC, 1 hour) in air | atmosphere atmosphere. As the inorganic _{binder, SiO} 2 (77 mol%), _ZrO 2 (10 _mol%), LiO 2 (3.5 mol%), _Na 2 O (4 _{mol%), K} 2 O (4 mol% ), A glass raw material containing CaO (0.7 mol%) and MgO (0.8 mol%) was melted and homogenized at 1600 ° C., and this was cooled and pulverized to an average particle diameter of 1 μm. A thing was used.

  Next, 20 parts by mass of an inorganic binder is added to 100 parts by mass of titania particles (aggregate) having an average particle size of 0.3 μm, and an organic binder, a pH adjuster, a surfactant, and the like are mixed to form a second intermediate A layer slurry was prepared.

  Next, the second intermediate layer slurry was deposited on the inner surface of the first intermediate layer by a filtration method, thereby forming a molded body of the second intermediate layer.

  Next, the 2nd intermediate | middle layer was formed by baking the molded object of a 2nd intermediate | middle layer (950 degreeC, 1 hour).

  Next, a glass raw material slurry was applied to the end face of the monolith substrate with intermediate layer by spray spraying, and then fired (950 ° C., 1 hour) to form a seal portion on the end face.

  Next, titanium isopropoxide was hydrolyzed in the presence of nitric acid to obtain a titania sol solution, which was diluted with water to prepare a separation (ultrafiltration) membrane slurry.

  Next, the separation membrane slurry was formed on the inner surface of the second intermediate layer by heat treatment (500 ° C., 1 hour).

(SEM observation of cross section of monolithic substrate)
First, the cross-sectional SEM image was acquired about the monolith type | mold base material of Examples 1-5 and Comparative Examples 1-4. 6 is a cross-sectional SEM image of Comparative Example 1, FIG. 7 is a cross-sectional SEM image of Comparative Example 3, and FIG. 8 is a cross-sectional SEM image of Example 1.

  Next, in the cross-sectional SEM image, the volume ratios of the aggregate, the binder, and the pores and the average aspect ratio of the aggregate particles were measured. The average aspect ratio is a value obtained by arithmetically averaging the aspect ratios (maximum ferret diameter / minimum ferret diameter) of 10 aggregate particles arbitrarily selected in the cross-sectional SEM image.

(Porosity and pore size distribution of monolithic substrate)
For monolithic substrate of Comparative Examples 3 and 4 with Examples 1-5, by mercury porosimetry was measured porosity and pore size distribution _{(D p 50, D p 10} , D p 90). The measurement results are as shown in Table 1. Moreover, the pore diameter distribution of Examples 1, 4, 5 and Comparative Example 3 is shown in FIG. 10 as a representative.

(Strength of monolithic substrate)
About the monolith type base material of Examples 1-5 and Comparative Examples 1-4, 4-point bending strength was measured based on JISR1601. The measurement results are as shown in Table 1.

In Comparative Example 1 (conventional example), as shown in FIG. 6, since the coarse aggregate alumina is used and the die is easily clogged during molding, the partition wall thickness cannot be reduced. In comparison with this, in Comparative Example 2, by using an aggregate having a small average particle diameter (D _g 50), a base material having a high membrane area in which the partition wall thickness is thin and the filtration cells are densified is formed. I was able to. However, the use of aggregates with a small average particle size increases the number of fine aggregate particles, resulting in a lack of binders that connect the aggregates, resulting in a significant decrease in strength and maintaining the structure of the separation membrane. I could not.

  In Comparative Example 3, when the proportion of the binder was increased as compared with Comparative Example 2, the strength was improved. However, in Comparative Example 3, as shown in FIG. 7, all the aggregates are connected, so that the strength and / or wear resistance is excessive (difficult to work), and the notch of the discharge channel is cut. The life of diamond disks for processing has been greatly shortened.

  On the other hand, in Example 1, as shown in FIG. 8, since the average particle size of the aggregate is small and the particle size distribution of the aggregate is sharpened by classification, it has sufficient strength even if there is little binder. At the same time, the service life of the diamond disc was extended. This is because the strength and / or wear resistance can be kept relatively low by reducing the number of binders.

  In Example 2, the life of the diamond disk could be further extended while maintaining sufficient strength by further reducing the binder. Moreover, in Example 3, even if the number of binders was increased, the strength of the monolithic base material could be further improved while the diamond disk had a sufficiently long life.

  Moreover, in Example 4, even if it does not classify | categorize all the aggregate raw materials, if the part was sharpened by classification, it has shown that the effect similar to Examples 1-3 can be exhibited.

  Moreover, in Example 5, even if it does not sharpen the particle size distribution of an aggregate by classification, if the ratio of an aggregate and a binder is fully adjusted, it has shown that the effect similar to Examples 1-4 can be exhibited. .

  On the other hand, in Comparative Example 4, because the aggregate particle size distribution was sharpened by the raw material and the specific surface area of the aggregate was reduced, there were too many binders, so the shrinkage (split) at the time of firing became large and pores The rate dropped and the pressure loss increased. Furthermore, the strength and / or wear resistance is excessive (difficult to work), and the life of the diamond disk for cutting the notch of the discharge channel is significantly shortened.

  In Examples 1 to 5 above, the reason why the machinability is good although the strength is relatively high is unknown, but it is presumed that the high aspect ratio of the aggregate has a good influence. In other words, since it is connected with relatively few binders and is flat, stress is likely to concentrate on the interface between the binder and the aggregate, and the aggregate particles are processed so as to peel off during cutting. It is guessed that.

  As shown in FIG. 10, Example 1 and Example 4 using the aggregate powder obtained by classification had a sharp pore size distribution. On the other hand, since Comparative Example 3 was broad and had many rough air holes, the intermediate layer slurry sometimes entered the inside of the base material to close the base material pores during the formation of the intermediate layer.

100 monolith type separation membrane structure 10 monolith type substrate 11S first end face 11T second end face 11U side face 12 first seal 13 second seal 14 first seal 15 second seal 20 intermediate layer 21 first Intermediate layer 22 Second intermediate layer 24 Filtration cell 25 Water collection cell 24L Filtration cell row 25L Water collection cell row 26 Drain passage 26a Opening

Claims (9)

A monolithic base material composed of an aggregate and a binder and having pores,
A plurality of filtration cells each extending from the first end face to the second end face;
A plurality of water collection cells each connected from the first end surface to the second end surface and sealed at both ends;
A discharge passage through the plurality of water collection cells;
With
The partition wall thickness of the shortest portion between two adjacent filtration cells among the plurality of filtration cells is 0.05 mm or more and less than 0.2 mm,
D _g 50 of the aggregate particles constituting the aggregate is 5 μm or more and less than 40 μm,
The volume ratio of the binder to the total volume of the aggregate and the binder is 15% by volume to 35% by volume.
Monolith type substrate. The D _g 10 of the aggregate particles is 10 ^(x−0.7) μm or more when the D _g 50 of the aggregate particles is 10 ^× μm,
The D _g 90 of the aggregate particle is 10 ^{(x + 0.3)} μm or less when the D _g 50 of the aggregate particle is 10 ^× μm.
The monolith substrate according to claim 1. D _p 50 of the pore is 1 μm or more and 10 μm or less,
The D _p 10 of the pore is 10 ^{(y + 0.2)} μm or less when the D _p 50 of the pore is 10 ^y μm,
The D _p 90 of the pore is 10 ^(y−0.2) μm or more when the D _p 50 of the pore is 10 ^y μm.
The monolith substrate according to claim 1 or 2. The volume ratio of the pores is 20% or more and 60% or less.
The monolith type substrate according to claim 3. Among the aggregate particles, the average aspect ratio of aggregate particles having a particle size of 10 μm or more is 2 or more.
The monolith substrate according to any one of claims 1 to 4. 4-point bending strength is 90 MPa or less,
The monolith substrate according to any one of claims 1 to 5. A plurality of filtration cells composed of aggregate powder and a binding material, each connected from the first end surface to the second end surface, and a plurality of water collecting units connected from the first end surface to the second end surface and sealed at both ends. A step of forming a monolith-type base material comprising a cell;
Forming a monolithic base material by firing the molded body;
Forming a slit for a discharge channel that penetrates the plurality of water collection cells by cutting the first end surface of the monolithic substrate; and
With
The partition wall thickness of the shortest portion between two adjacent filtration cells among the plurality of filtration cells is 0.05 mm or more and less than 0.2 mm,
D _g 50 of the aggregate powder is 5 μm or more and less than 40 μm,
The volume ratio of the binder to the total volume of the aggregate and the binder is 15% by volume to 35% by volume.
Monolith type substrate manufacturing method. D _g 10 of the aggregate powder is 10 ^(x−0.7) μm or more when the D _g 50 of the aggregate powder is 10 ^× μm,
The D _g 90 of the aggregate powder is 10 ^{(x + 0.3)} μm or less when the D _g 50 of the aggregate powder is 10 ^× μm.
The manufacturing method of the monolith type base material of Claim 7. Of the aggregate powder, the average aspect ratio of aggregate powder particles having a particle size of 10 μm or more is 2 or more.
The manufacturing method of the monolith type | mold base material of Claim 7 or 8.