JP4523924B2 - Ceramic straight tube hole cylindrical support and oxygen separation membrane - Google Patents

Description

  The present invention relates to a cylindrical ceramic support having a straight pipe hole that passes straight from an outer peripheral surface to an inner peripheral surface that can be used as a support for an oxygen separation membrane, and an oxygen separation membrane.

  For example, an oxygen separation membrane using a mixed conductor solid electrolyte membrane is known. In this type of oxygen separation membrane, the thinner the electrolyte membrane, the higher the oxygen transmission rate and the higher the separation performance. Therefore, instead of the self-supporting membrane used as a single membrane, the membrane is formed on a porous support having a large number of pores penetrating in the thickness direction for the purpose of supplementing the mechanical strength of the electrolyte membrane with a thin film. (That is, forming an asymmetric film) (see, for example, Patent Documents 1 and 2).

  Further, the oxygen separation membrane is considered to be preferably cylindrical, for example, cylindrical, considering use on a practical scale such as a gas separation membrane for chemical plants (see, for example, Patent Documents 3 and 4). ). The cylindrical element is relatively easy to seal and increase in size as compared with a flat plate structure. In addition, since a plurality of devices can be bundled closely together, it is advantageous in that the device can be miniaturized.

Due to the above circumstances, a cylindrical porous support is used, but in the asymmetric membrane structure, the gas diffusion performance of the porous support immediately affects the performance of the apparatus. Therefore, in order to produce an oxygen separation membrane with high separation performance, a support having high gas diffusibility is required. Further, in order to obtain a highly durable oxygen separation membrane, a support having high mechanical strength and high affinity for the electrolyte thin film is required. Furthermore, it is desired that it can be manufactured easily and inexpensively for practical use.
Japanese Patent No. 2813596 JP 2003-210952 A JP 2002-083517 A JP 2002-292234 A Japanese Patent Laid-Open No. 2005-052698 JP 2002-097083 A Japanese Patent Laid-Open No. 09-132559 JP 09-087024 A Japanese Patent No. 3540495 JP-A-11-099324

Conventionally, various methods for producing a porous support for supporting an electrolyte thin film have been proposed from the viewpoints of raw materials, added pore forming agents, firing methods, and the like. For example, La _1-x Ae _x MO ₃ (where Ae is at least one of Ba, Sr, and Ca, and M is at least one of Fe, Mn, Ga, Ti, Co, Ni, Al, In, Sn, and Zn). Using a raw material having an average particle diameter of 10 (μm) or more, and firing at a high temperature, preferably higher than the firing temperature of the electrolyte membrane provided on the porous support (for example, Patent Documents) (See 5). Further, when obtaining a porous support by mixing and molding a resin to a mixed conductive oxide raw material composed of AFe _x O _3-δ (where A is at least one of Ba, Sr, and Ca). There is one that changes its porosity by adjusting the amount of resin to be mixed, molding pressure, and firing temperature (see, for example, Patent Document 6). In addition, carbon beads are mixed into a raw material consisting of ABB'O ₃ (where A is a metal component that is 12-coordinated with oxygen, and B and B 'are components that are 6-coordinated with oxygen), and then oxidized There is one in which the carbon beads are burned off by firing in an atmosphere, and the burnt-out traces become pores (see, for example, Patent Document 2). Also, lanthanum perovskite raw material is mixed with finely powdered carbon powder with a large specific surface area, for example, carbon powder with an average particle size of 1 to 10 (μm) and a specific surface area of 200 (m ² / g) or more, and an oxidizing atmosphere In some cases, pores are formed by burning the carbon powder and burning off the carbon powder (see, for example, Patent Documents 7 and 8). By any of the above production methods, a porous support having a pore diameter and a porosity range that does not inhibit oxygen permeation has been obtained.

  Incidentally, in recent years, with the improvement of the performance of solid electrolyte membranes and catalysts, the gas diffusion performance of porous supports has come to regulate the performance of oxygen separation membranes. Therefore, further improvement of the gas diffusion performance of the porous support is required. In order to improve the gas diffusion performance, it is conceivable to further increase the pore diameter and porosity of the porous support. However, the mechanical strength of the porous support decreases as the pore diameter and porosity increase. For example, when the porosity is increased to about 90 (%), the material strength is decreased to about 10 (MPa), and the handleability and durability become insufficient. Moreover, in the manufacturing method described in each of the above publications, communication holes are formed by voids between particles. Therefore, since the communication holes are remarkably bent, it is difficult to sufficiently improve the gas diffusion performance even when the porosity and the pore diameter are increased.

  On the other hand, as a separation membrane provided with a membrane on a support, a metal base pipe having a large number of holes for ventilation is used as a support, and a hydrogen permeable metal foil is superimposed on the outer peripheral surface thereof. It has been proposed (see, for example, Patent Documents 9 and 10). Since the straight tubular hole that penetrates linearly in the thickness direction of the support body has a remarkably low ventilation resistance as compared with the bent communication hole, the gas diffusion performance can be remarkably improved.

  However, the base pipes described in Patent Documents 9 and 10 are metal porous supports intended for use in hydrogen separation, and are not directly applicable to oxygen separation. In the oxygen separation application, since it is exposed to a high temperature, a high pressure, a reducing atmosphere, or a water vapor atmosphere, it is desired that the support is composed of ceramics having reduction resistance, water vapor resistance, and high mechanical strength. Although straight pipe holes can be easily provided in a metal cylinder, it is extremely difficult to provide a large number of straight pipe holes in ceramics that are inferior in machinability. For example, if a molded body or sintered body is machined to provide holes similar to those described in Patent Documents 9 and 10, the number of holes that can be formed at one time is one to several at most. Since it is less than 10, a great deal of labor is required. In addition, since the through-hole is formed in the curved surface, there is a problem that complicated control is required in order to ensure the position, the dimensional shape accuracy, and the like.

  The present invention has been made in the background of the above circumstances, and an object thereof is to provide a ceramic cylindrical support having a straight pipe hole with high gas diffusion performance and an oxygen separation membrane with high oxygen permeation rate. There is.

  In order to achieve such an object, the gist of the ceramic straight tube hole cylindrical support for the oxygen separation membrane of the first invention is that (a) each has a through hole penetrating in the thickness direction in the inner peripheral portion. And a plurality of ceramic perforated plate-like portions continuous in the thickness direction at a predetermined interval, and (b) arranged between the annular end faces of the plurality of perforated plate-like portions at a predetermined mutual interval in the circumferential direction. In addition, the entire structure includes a plurality of connecting portions made of ceramic that connect the plurality of perforated plate-like portions to each other.

  Further, the gist of the oxygen separation membrane of the second invention for achieving the above object is that a dense membrane made of a mixed conductor is fixed to the surface of the ceramic straight tube hole cylindrical support of the first invention. There is.

  According to the first invention, in the ceramic straight tube hole cylindrical support, a plurality of ceramic perforated plate-like portions are connected to each other by a ceramic connecting portion provided between their annular end faces. Consists of. At this time, since the plurality of perforated plate-like portions are continuous in the thickness direction, a hole extending along the thickness direction is substantially formed on the inner peripheral side by the through holes, and the support body has a cylindrical shape as a whole. Make it. In addition, since the plurality of connecting portions are arranged with a predetermined mutual interval in the circumferential direction of the annular end surface, between the connecting portions between the annular end surfaces of the plurality of perforated plate-like portions, there is a perforated plate shape. A straight pipe hole penetrating linearly from the outer peripheral surface side to the inner peripheral surface side is provided. That is, the support according to the first aspect of the present invention has a cylindrical shape as a whole and includes a large number of straight pipe holes that penetrate the inner and outer peripheral surfaces linearly on the side wall. The diameter of the straight pipe hole is determined by the mutual interval of the perforated plate-like portions and the mutual interval of the connecting portions in the circumferential direction of the annular end surface. Therefore, by appropriately determining these sizes, the desired gas diffusion A straight pipe hole having an appropriate size according to the performance can be obtained. Therefore, a ceramic cylindrical support having straight pipe holes with high gas diffusion performance can be obtained.

  Further, according to the second invention, since the dense membrane made of the mixed conductor is fixed to the surface of the ceramic cylindrical support having a straight pipe hole with high gas diffusion performance, the dense membrane (that is, the electrolyte membrane) A gas containing oxygen is preferably supplied, or oxygen that has permeated the dense membrane is preferably passed through the support. Therefore, it is possible to preferably alleviate or avoid that the gas diffusion performance of the support regulates the oxygen permeation performance of the oxygen separation membrane, so that an oxygen separation membrane having a high oxygen permeation rate can be obtained.

  The term “between the annular end faces” means that at least a part of the connecting portion is disposed in contact with the annular end face. For example, the entire connecting member having a columnar shape or the like is provided on the annular end face. However, it does not matter even if a part protrudes from the outer peripheral side or inner peripheral side of the annular end face. Further, the connecting portion is not limited to one having a uniform cross section in the thickness direction of the perforated plate-like portion, and for example, the cross-sectional area of the intermediate portion may be larger or smaller than both ends. For example, the intermediate portion may have a small area and be positioned on the outer peripheral side of the annular end surface.

  Moreover, the connection part should just be divided | segmented into at least two in the circumferential direction, and the magnitude | size of a division | segmentation number or a mutual space | interval is not ask | required in particular. However, the larger the area occupied by the connecting portion on the annular end surface, the higher the mechanical strength, but on the other hand, the porosity of the side wall when the entire support is regarded as a cylindrical body decreases, and as a result gas diffusion performance Therefore, the area is preferably determined so that the strength can be secured in a range in which the porosity is not too small. The mechanical strength of the support is preferably, for example, 30 (MPa) or more in terms of bending strength. The above-mentioned “porosity in the side wall” refers to an outer peripheral cylindrical curved surface and an inner peripheral cylindrical curved surface formed by connecting the outer peripheral surface and the inner peripheral surface of a plurality of perforated plate-like portions constituting the support, respectively. It means the ratio of the void to the volume of the part between them. In the present application, the porosity of the support of the first invention is treated as the porosity. It should be noted that the porosity of the component other than the support of the first invention, that is, its constituent elements, an intermediate layer described later, a conventional support, and the like is a value measured by a mercury intrusion method or the like according to a normal definition.

  Further, the through holes are preferably provided coaxially in the plurality of perforated plate-like portions, but the holes formed by the plurality of through holes cause an obstacle to gas flow and extend the oxygen transmission rate. If it is not bent to such an extent that it has a significant influence, it does not matter if it is not provided coaxially. In addition, the size of each of the plurality of through holes is preferably uniform, but may vary within a range that does not significantly affect the oxygen transmission rate from the same viewpoint.

  In addition, the shape and size of the outer peripheral edge of the plurality of perforated plate portions are preferably uniform, but may be varied within a range that does not hinder the fixing of the electrolyte membrane.

Here, preferably, the ceramic straight tube hole cylindrical support has a general formula Ln _1-x Ae _x MO ₃ (where Ln is at least one selected from lanthanoids, Ae is selected from Sr, Ca, Ba) At least one selected from the group consisting of Fe, Mn, Ga, Ti, Co, Ni, Al, In, Sn, Zr, V, Cr, Zn, Ge, Sc, and Y, 0 ≦ x ≦ 1 ) Selected from perovskite composite oxide, stabilized zirconia, cerium oxide, at least two of these composite materials, and at least one of these and silicon oxide, silicon nitride, titanium oxide, and aluminum oxide And at least one ceramic material selected from at least one composite material. In this way, the perovskite complex oxide, stabilized zirconia, and cerium oxide tend to have relatively high oxygen ion conductivity among ceramic materials. Therefore, when the support is composed of these or these composite materials, oxygen passes not only through the straight pipe hole of the support but also through the support, so that the permeation resistance of oxygen in the support is further reduced. Therefore, if a support made of these materials is used, an oxygen separation membrane with a higher oxygen transmission rate can be obtained. Although silicon oxide, silicon nitride, titanium oxide, and aluminum oxide have low oxygen ion conductivity, they have relatively high mechanical strength and are inexpensive, so that they have oxygen ion conductivity such as perovskite composite oxide. A support made of a composite material with a high material has an advantage that it has a relatively high oxygen ion conductivity and can be manufactured with high strength at low cost.

  The perovskite composite oxide is generally a mixed conductor having both high oxygen ion conductivity and high electron conductivity, depending on the constituent elements and the constituent ratios of the A site element and B site element. A composite material of the composite oxide and the other materials is also a mixed conductor. When the support is configured with such a mixed conductor, oxygen permeation resistance in the support is further reduced, and it is not necessary to provide an external electrode or an external circuit when configuring the oxygen separation membrane. There is an advantage that the device configuration is simplified.

  In addition, the perovskite compound and the like are similar in thermal expansion coefficient to the electrolyte membrane for constituting the oxygen separation membrane, so that they are damaged due to the difference in the amount of thermal expansion even when heated or cooled during the manufacturing process or use. There is also an advantage that it is suitably suppressed.

Examples of the lanthanoid-based perovskite composite oxide used in the first and second inventions include LaSrTiFeO ₃ , LaSrGaFeO ₃ , and LaSrMnFeO ₃ . These have the advantages of high ion conductivity and electron conductivity, and the support itself has an oxygen permeation effect.

  Stabilized zirconia and cerium oxide are inferior in oxygen ion conductivity and electronic conductivity as compared with the lanthanoid series, but on the other hand, they have higher strength than these. Therefore, it is also preferable to use these when the required mechanical strength is relatively high.

  The stabilizer for the stabilized zirconia is not particularly limited, and those added with various stabilizers such as yttria, ceria and magnesia can be used.

  In addition, aluminum oxide, silicon oxide, silicon nitride, and titanium oxide have low electronic conductivity and oxygen ion conductivity that is significantly lower than that of lanthanoid-based materials, but have the advantages of relatively inexpensive raw materials and high mechanical strength. Therefore, it is not limited to a composite material of perovskite composite oxide, stabilized zirconia, and cerium oxide, and it is also effective to form a support with these aluminum oxide, silicon oxide, silicon nitride, and titanium oxide.

  Preferably, the interval between the plurality of perforated plate portions is in the range of 0.01 to 50 (mm). In order to sufficiently reduce the gas diffusion resistance in the support, the mutual interval is preferably set to 0.01 (mm) or more. In general, in a porous body, if the pore diameter is 1 (μm) or more, there is no gas flow resistance in relation to the mean free path of gas molecules. Since the above mutual distance corresponds to the diameter of a straight pipe hole penetrating between the inner and outer peripheries of the support, it is necessary to consider gas diffusion resistance if it is 0.01 (mm) or more even if manufacturing variation is taken into consideration There is no. Further, in order to easily form the electrolyte membrane on the support and to sufficiently increase its holding strength, the mutual interval is preferably 50 (mm) or less, depending on the method of forming the electrolyte membrane. .

  More preferably, the mutual interval is 5 (mm) or less. If it is 5 (mm) or less, the possibility that the intermediate layer will be damaged when an intermediate layer to be described later is formed on the support is sufficiently low.

  Preferably, the plurality of perforated plate-like portions are coaxially positioned, and a portion between the outer peripheral side cylindrical curved surface and the inner peripheral side cylindrical curved surface including the outer peripheral surface and the inner peripheral surface, respectively. The porosity is in the range of 20 to 95 (%). As described above, this porosity substantially corresponds to the porosity in the side wall of the support. In order to obtain a sufficiently high gas diffusion performance, the porosity is preferably set to 20 (%) or more, and in order to ensure mechanical strength, the porosity is preferably set to 95 (%) or less.

  In addition, the plurality of connecting portions constituting the support body of the first invention may be constituted by independent members provided at various places on the annular end surface of the perforated plate-like portion, but one annular end surface What is provided above may be mutually connected in a part in the thickness direction of the perforated plate-like portion. Moreover, a connection part may be comprised by the part located between the perforated plate-shaped parts among the members continuous in the thickness direction of a perforated plate-shaped part.

  Further, the perforated plate-like portion and the connecting portion located on the annular end surface may be integrally formed. For example, a member in which a plurality of protrusions protruding in the thickness direction are provided at appropriate mutual intervals on, for example, the outer peripheral edge portion on one annular end surface of the perforated plate-like portion, and a plurality of these members are overlapped with each other. It is also possible to configure the support by bonding to.

  Moreover, although the shape of a connection part is cylindrical, for example, it is not restricted to this, It can be set as prismatic shape and other appropriate shapes.

  Preferably, the perforated plate-like portion is provided with a recess or a through hole (another through hole different from the through hole of the inner peripheral portion) that matches the cross-sectional shape of the connecting portion, and the connecting portion. Are to be fitted into these recesses or other through holes. In this way, the connecting portion is prevented from shifting along the surface on the annular end surface, so that the plurality of perforated plate-like portions may be displaced from each other and the straightness of the entire support body may be reduced. It is preferably suppressed. Further, since the displacement of the connecting portion is suppressed, the straight pipe hole is formed at a desired position and size. Even when the connecting portion is formed integrally with the perforated plate-like portion, the same effect can be obtained by providing a recess or other through hole at a position corresponding to the connecting portion of the other perforated plate-like portion. Can enjoy.

  Preferably, the plurality of perforated plate-like portions are provided with other through holes in addition to the through holes in the inner peripheral portion. A long guide bar that pierces the through-hole is provided. If it does in this way, while the mutual space | interval of a perforated plate-shaped part will be defined by a connection part, the position shift in the direction perpendicular | vertical to the axial direction of a perforated plate-shaped part will be suppressed with the elongate rod for guidance.

  Preferably, the perforated plate-like portion and the connecting portion are made of the same material. That is, even when they are not integrally formed, they are preferably made of the same material. In this way, it is easy to handle in the manufacturing process because it is the same material, and because it has the same thermal expansion coefficient, it can be damaged due to differences in the amount of thermal expansion during the manufacturing process and use. Is suitably suppressed.

  Further, when the oxygen separation membrane is configured using the support of the present invention, the porosity is smaller than the porosity of the support (that is, the porosity) between the support and the dense membrane made of the mixed conductor. An intermediate layer is provided. In this way, there is an advantage that a dense film can be easily formed as compared with the case where it is provided directly on the support. In addition, although this intermediate | middle layer may be comprised with the material same as a perforated plate-shaped part and a connection part, you may comprise with a different material. In the case of using the same material, it is preferable to use a raw material having a particle size larger than that of the perforated plate-like portion so that the firing shrinkage is sufficiently small. In the case of using different materials, it is preferable to use a material having a difference in thermal expansion coefficient as small as possible between the perforated plate-like portion and the dense film and having low reactivity with the dense film. Further, the intermediate layer preferably has a porosity of 20 (%) or more within a pore diameter range of about 0.1 to 10 (μm). More preferably, the pore diameter is 5 (μm) or more and the porosity is about 20 to 30 (%).

  In addition, the support of the present invention has a perforated plate-like portion and a connecting portion that are dense, and has a suitable void as a whole by joining them so that a void is formed. preferable. In this way, manufacture becomes easier as compared with a case where the entire support is integrally formed. Moreover, since each part of the component of a support body is precise | minute, since it has high mechanical strength, it is easy to give high mechanical strength to the whole after joining. That is, the perforated plate-like portion and the connecting portion may be porous or dense, but are preferably dense so as to obtain as high mechanical strength as possible.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. In the following embodiments, the drawings are appropriately simplified or modified, and the dimensional ratios, shapes, and the like of the respective parts are not necessarily drawn accurately.

  FIG. 1 is a perspective view showing an entire ceramic straight tube hole cylindrical support 10 (hereinafter referred to as support 10) according to an embodiment of the present invention. The support 10 has a substantially cylindrical shape, for example, having a size of an outer diameter of 20 (mm) × an inner diameter of 14 (mm) × a length of 300 (mm), and has a plurality of perforated disks. 12 are fixed to each other in a state of being stacked via support columns 14. In this embodiment, the perforated disc 12 corresponds to a perforated plate-like portion, and the support column 14 corresponds to a connecting portion.

  The above-described perforated disk 12 has a through-hole 16 penetrating in the thickness direction in the inner peripheral portion, concentrically with the outer peripheral edge, and has an outer diameter 20 (mm) × inner diameter 14 (mm) × thickness 1.5 (mm). ) About the size. Further, each of the columns 14 has a columnar shape with a diameter of about 1.5 (mm) × a length of about 1.5 (mm). On the annular end surface 18 of the perforated disc 12, the columns 14 are equally spaced in the circumferential direction. Four are arranged. Therefore, each of the plurality of perforated discs 12 has an opening diameter of about 1.5 (mm) × 10 (mm) and linearly penetrates from the outer peripheral edge of the annular end surface 18 to the inner peripheral edge 4. Two straight pipe holes 20 are provided respectively.

In addition, the above-described perforated disk 12 and support column 14 are, for example, La _0.6 Sr _0.4 Ti _0.3 Fe _0.7 O ₃ (hereinafter referred to as LSTF) or La _0.6 Sr _0.4 Zr _0.2 Fe _0.8 O ₃ (hereinafter referred to as LSZF). These are dense bodies made of lanthanum perovskite complex oxides, etc., have a porosity of less than 1 (%), and are integrated by being firmly joined by firing treatment. Note that the plurality of perforated disks 12 are all configured to have the same shape and the same dimensions, and the outer peripheral surface and the inner peripheral surface thereof are located on one cylindrical surface.

Further, as described above, the support body 10 is composed only of dense constituent members, but the four straight pipe holes 20 are provided between the perforated disks 12 as described above. Yes. Therefore, when viewed as the entire support 10, the portion between the outer peripheral cylindrical surface including the outer peripheral surface of the perforated disk 12 and the inner peripheral cylindrical surface including the inner peripheral surface is, for example, about 48 (%). It is a porous cylinder provided with the following porosity. Further, the gas permeability between the outer and inner peripheral surfaces of the porous cylinder is an extremely high value of about 1.2 × 10 ⁻³ (mol / Pa / m ² / s), for example.

  For example, as shown in FIG. 2, the support 10 is used as an oxygen separation membrane 24 by forming a dense membrane (electrolyte membrane) 22 made of a mixed conductor on the outer peripheral surface. At this time, a porous intermediate layer 26 having a porosity and a pore diameter sufficiently smaller than that of the support 10 is provided between the support 10 and the dense film 22 as necessary. The dense film 22 is preferably made as thin as possible in order to obtain a high oxygen transmission rate, and is provided with a thickness of about 100 (μm), for example. Therefore, when it is difficult to directly provide such a thin film on the outer peripheral surface of the support 10, the intermediate layer 26 is provided. The intermediate layer 26 is provided with a thickness of about 0.1 to 0.3 (mm), for example, so that the intermediate layer 26 can maintain its shape on the support 10 itself. The intermediate layer 26 has a pore diameter of, for example, about 0.1 to 10 (μm), and a porosity of 20 (%) or more.

  The dense film 22 is made of, for example, LSTF. That is, the dense film 22 can be composed of the same material as the support 10. The intermediate layer 26 is made of, for example, LSTF or LSZF. The intermediate layer 26 is also preferably made of the same material as the support 10.

  Since the support body 10 configured as described above is configured by connecting the perforated discs 12 to each other by the columns 14 provided between the annular end faces 18, the support body 10 as a whole. A hole extending in the longitudinal direction is provided on the inner peripheral side. Moreover, since the four support posts 14 are arranged at equal intervals in the circumferential direction of the annular end surface 18, the diameter of the hole penetrating linearly from the outer peripheral surface of the support 10 to the inner peripheral surface between the support posts 14 is 1.5. The support body 10 having a straight pipe hole 20 of about (mm) and having a cylindrical shape as a whole has a high porosity of about 45 (%). Therefore, according to this embodiment, the support 10 having the straight pipe hole 20 with high gas diffusion performance can be obtained.

  Further, since the oxygen separation membrane 24 is configured by fixing the dense membrane 22 to the outer peripheral surface of the support 10 having a high gas diffusion performance as described above, the support 10 is formed of the entire oxygen separation membrane 24. Controlling the oxygen transmission rate is preferably suppressed. Therefore, an oxygen separation membrane 24 having a high oxygen transmission rate according to the constituent material and film thickness of the dense membrane 22 is obtained.

  By the way, said support body 10 is manufactured as follows, for example. Hereinafter, an example of the manufacturing method will be described with reference to the process diagram of FIG.

  First, in the mixing step PS1, a binder and a dispersing agent are mixed with raw material powders of perovskite complex oxides such as LSTF and LSZF for forming the perforated disks 12 and the columns 14. As the raw material powder, commercially available appropriate powders can be used. For example, powders having an average particle diameter of about 1 (μm) are used. Next, in the granulation step PS2, the mixture is granulated by an appropriate method such as spray granulation. The particle diameter after granulation is, for example, about 60 (μm).

  Next, in the molding step PS3, a molded body for manufacturing the perforated disk 12 and the support column 14 is molded using the above granulation raw material using an appropriate molding method such as a powder press molding method. To do. The former molding dimensions are, for example, an outer diameter of 25 (mm), an inner diameter of 17 (mm), and a thickness of about 2 (mm). The latter molding dimensions are, for example, a diameter of 2 to 3 (mm) and a thickness of about 2 (mm). These are further subjected to wet isostatic pressing (CIP) of about 150 (MPa) as necessary.

  Next, in the firing step PS4, the molded body is subjected to a firing treatment in the air. The baking treatment is performed by, for example, maintaining the temperature at about 200 to 500 (° C.) for about 10 hours to decompose the organic matter, then raising the temperature to about 1000 to 1600 (° C.) and holding it for about 3 hours. Next, in the polishing step PS5, the obtained fired product is mechanically polished to be processed into a desired dimension. The thickness dimension after processing is, for example, about 1.5 (mm). If necessary, the inner and outer diameters of the perforated disk 12 and the outer diameter of the support 14 may be polished. The dimensions after polishing are as follows: the perforated disk 12 has an inner diameter of 14 (mm) and an outer diameter. About 20 (mm), the support column 14 has an outer diameter of about 1.5 (mm). 4 and 5 show the fired product, that is, the perforated disk 12 and the support column 14 after being polished.

  Next, in the joining step PS7, the above-described perforated disk 12 and the support column 14 are superposed and subjected to a firing treatment at a temperature of about 1300 to 1600 (° C.), for example, to join them. Thereby, the support body 10 as shown in FIG. 1 is obtained. Therefore, according to the present embodiment, the support body 10 can be obtained simply by making the perforated disk 12 and the support column 14 and joining them together, so that the support having the straight pipe hole 20 and having a high porosity is obtained. The body 10 can be obtained very easily.

  The oxygen separation membrane 24 is manufactured according to the process shown in FIG. 6, for example, using the support 10 manufactured as described above.

  First, in the sheet forming process PR1, for example, an LSTF or LSZF raw material having an average particle size of about 20 to 50 (μm) is prepared, and a solvent, a binder, a plasticizer, and a dispersant are added to the raw material and mixed. A slurry is prepared, and a sheet is formed using, for example, a doctor blade method. The molding dimensions are, for example, a width dimension of 100 (mm), a length of 1000 (mm), and a thickness of about 100 to 300 (μm). Since the intermediate layer 26 needs to be porous as described above, a coarser layer is used as compared with the raw material for manufacturing the perforated disk 12 or the like. Next, in the winding step PR2, the sheet-like molded body is cut into a desired size and shape and wound around the outer peripheral surface of the support 10. In addition, when the sheet molded body has sufficient plasticity, it does not peel off from the support 10 even if it is wound as it is, but in the case of peeling, a small amount of the surface of the support 10 or the surface of the sheet molded body What is necessary is just to wind after apply | coating a plasticizer.

  Next, in the intermediate layer firing step PR3, the support 10 on which the sheet-like molded body is wound is subjected to firing treatment by, for example, holding in the atmosphere at a temperature of about 1000 to 1600 (° C.) for about 3 hours. Thereby, the porous intermediate | middle layer 26 is produced | generated from a sheet-like molded object. The generated intermediate layer 26 has, for example, a pore diameter of about 5 to 10 (μm) and a porosity of about 20 to 30 (%).

  Next, in the film forming step PR4, for example, a solvent, a binder, a plasticizer, a dispersing agent, and the like are added to an LSTF powder having an average particle diameter of about 1 to 2 (μm) and mixed to prepare a slurry. The support 10 on which the intermediate layer 26 is generated in the slurry is dipped and the slurry is applied to the outer peripheral surface thereof. The coating thickness is, for example, about 100 (μm). Next, in the film baking step PR5, the dense film 22 is generated from the slurry by holding in the atmosphere at a temperature of about 1000 to 1600 (° C.) for about 3 hours. Thereby, the oxygen separation membrane 24 is obtained.

  In the above manufacturing method, the intermediate layer 26 is made of the same material as that of the support 10. However, the intermediate layer 26 may be made of a material different from that of the support 10. For example, it is preferable to use a highly sinterable raw material because the perforated disk 12 and the column 14 need to be dense, but the intermediate layer 26 needs to be porous, so that It is preferable to use a raw material having a sufficiently low sinterability. For example, if a part of the B site element of LSTF and LSZF constituting the perforated disk 12 or the like is changed, a suitable non-sinterable raw material can be obtained for the intermediate layer 26 within a range in which the thermal expansion coefficient is not largely changed. It is done.

For example, as the constituent material of the intermediate layer 26, La _0.6 Sr _0.4 Zr _0.3 Fe _0.7 O ₃ or La _0.85 Sr _0.15 MnO ₃ having an average particle diameter of about 10 (μm) can be used. A solvent is added to these raw material powders in the same manner as in the sheet forming step PR1 to prepare a slurry, and a sheet is formed in the same manner. The intermediate layer 26 obtained from this slurry has, for example, a pore diameter of 1 to 3 (μm) and a porosity of about 30 (%).

  Hereinafter, the results of evaluating the characteristics of the support 10 and the oxygen separation membrane 24 manufactured using various raw materials in the above configuration examples and manufacturing method examples will be described.

  Table 1 below summarizes the evaluation results. In Table 1, the “tubular support” column represents the constituent material and shape of the support 10. The “film” column represents the constituent material of the dense film 22 formed on the support. The “support pore diameter” and “porosity” columns represent the pore diameter and porosity of the support, respectively. The “gas permeability” column shows the gas permeability measured by the support alone, and the “oxygen transmission rate” column shows the oxygen permeability measured at 1000 (° C.) with the dense film 22 provided on the support. The transmission speed is shown.

  In Table 1, for the support pore diameter, the mutual interval of the perforated discs 12, that is, the height dimension of the support column 14 is used in the case of the straight pipe hole, that is, the example. On the other hand, the non-straight pipe hole, that is, the comparative example, is an actual measurement value measured by a mercury intrusion method. Further, the porosity is a value obtained by calculating the volume between the inner and outer peripheral surfaces and the space volume thereof by calculation and calculating the space portion as the pore. About a comparative example, it is the value measured by the mercury intrusion method. The gas permeability is such that the both ends of the support are hermetically sealed and a gas supply path is provided at one end of the support, and air is supplied from the gas supply path to the support, and the relationship between the supply gas pressure and the flow rate. It is a value calculated from The oxygen transmission rate was measured in the same manner as the gas permeability measurement, and was calculated from the oxygen flow rate permeated through the dense membrane 22, the oxygen concentration in the supplied gas, and the oxygen permeation area of the oxygen separation membrane 24.

  In Table 1 above, Nos. 1 to 5, 7 to 11, and 13 to 16 are examples within the scope of the present invention, and Nos. 6 and 12 are comparative examples outside the scope of the present invention. In these comparative examples, for example, a support was produced as follows.

  That is, for example, LSTF and LSZF raw material powders having an average particle size of about 20 to 50 (μm) are prepared, a binder and a dispersant are mixed with each, and granulated using an appropriate method such as spray granulation. The average particle size after granulation is, for example, about 80 (μm). This is filled into a cylindrical mold, and press-molded at a pressure of, for example, about 150 (MPa) using a wet isostatic pressing method. Next, the obtained molded body is fired in the air. For example, the baking treatment is held at 200 to 500 (° C.) for about 10 hours, and then held at 1000 to 1600 (° C.) for about 3 hours. By subjecting this fired body to mechanical polishing, a support of a comparative example is obtained. That is, the support of the comparative example is a conventional porous support in which pores are formed by voids generated between the particles by using a raw material powder having a large average particle diameter.

In Table 1 above, LSAF is La _0.6 Sr _0.4 Al _0.1 Fe _0.9 O ₃ , LSGF is La _0.7 Sr _0.3 Ga _0.6 Fe _0.4 O ₃ , and LSMF is La _0.6 Sr _0.4 Mn _0.3 Fe _0.7 O ₃ . No. 16 is a composite material in which LSTF and 3 molY stabilized zirconia are mixed at a mass ratio of 1: 1.

As shown in the above evaluation results, the support of the comparative example has only a pore diameter of only about 10 (μm) and the porosity is only about 30 (%), whereas the support of the embodiment has a support column. It has an extremely large pore diameter corresponding to the thickness dimension of 14, and the porosity is 40 (%) or more. As a result, the gas permeability of the support 10 reaches 9.5 × 10 ⁻³ (mol / Pa / m ² / s) when it is high, and 1.2 × 10 ⁻³ (mol / Pa / m ² / s) even when it is low. However, it was only 6.5 × 10 ⁻⁵ (mol / Pa / m ² / s) in the comparative example. For this reason, the oxygen separation membrane 24 using the support 10 of the embodiment has a gas diffusion performance of the support 10 that does not regulate the characteristics of the oxygen separation membrane 24, and is about 13 to 19 (cc / min / cm ² ). A high oxygen transmission rate was obtained. On the other hand, in the comparative example, since the gas permeability of the support is low, the characteristics of the dense membrane 22 are not sufficiently exhibited, so that the oxygen transmission rate is as low as about ^{2 to} 3 (cc / min / cm ² ). It was.

  According to the above evaluation results, it is clear that the support 10 and the oxygen separation membrane 24 of the present example have remarkably high characteristics as compared with the prior art. In addition, it is apparent that the pore diameter, that is, the interval between the perforated discs 12 can be used within the range of 500 to 5000 (μm). Although not shown in Table 1 above, when the mutual interval is set to 7000 (μm) or 10000 (μm), some deformation is observed when the intermediate layer 26 is formed, and cracks occur when the dense film 22 is fired. Oxygen separation membrane 24 could not be manufactured stably.

  Note that, among the examples, in the case of using the support of the LSTF straight pipe hole, in the range of the support pore diameter of 1000 (μm) or less, in the case of using the support of the LSZF straight pipe hole, the support pore diameter However, in the range of 500 (μm) or less, the characteristics are slightly inferior to those having pore diameters exceeding those. Therefore, the desirable pore diameter is 1000 (μm) or 1500 (μm) or more, although it depends on the constituent material of the support 10 and the dense membrane 22.

  FIG. 7 shows a pillar-integrated disc 34 in which a perforated disc portion 28 and strut portions 30 and 32 for constituting a ceramic straight tube hole cylindrical support according to another embodiment of the present invention are integrally provided. It is a perspective view shown. In FIG. 7, the column-integrated disk 34 has four column portions 30 on one annular end surface 36 at equal intervals in the circumferential direction, and four column portions 32 on the other annular end surface 38 in the circumferential direction. Provided for spacing. These column portions 30 and 32 have a substantially rectangular planar shape, have the same height dimension, and are positioned at the middle portion in the other circumferential direction, and the sum of their circumferential dimensions is The outer circumferential edges of the annular end surfaces 36 and 38 are shorter than the circumference. The size of the support columns 30 and 32 is, for example, about 3 × 3 × 1.5 (mm), and is arranged in a range from the outer peripheral edge to the inner peripheral edge of the annular end surface of the perforated disk portion 28.

  Therefore, when such support-integrated discs 34 are superposed, they have a circumferential dimension corresponding to the difference between the sum of their circumferential dimensions and the circumference of the outer peripheral edge, and the height dimensions of the support columns 30 and 32. A gap having a height dimension equal to is linearly provided between the inner and outer peripheries of the columnar integrated disc 34. Therefore, according to this aspect, as compared with the case where a member functioning as a support is manufactured separately, it is only necessary to manufacture one type of component, and the components are simply overlapped and joined. Since the support similar to 10 is obtained, there is an advantage that the manufacturing process is further simplified.

  FIG. 8 is a view showing a support-integrated disk 46 in which support sections 40 and 42 are integrally provided on both surfaces of a perforated disk section 44 as in FIG. The column portions 40 and 42 are provided at the same position in the circumferential direction of the perforated disc portion 44. Each of the column portions 40 and 42 has a size of about 3 × 1 × 1.5 (mm), for example, and ranges from the outer peripheral edge to the inner peripheral edge along the radial direction of the annular end surface of the perforated disk portion 44. Is arranged. Therefore, when using this column integrated disc 46, for example, the columns arranged in contact with each other are rotated and overlapped with each other in the circumferential direction by a length that is half the center interval in the circumferential direction of the column part 40. Thereby, the support body similar to FIG. 7 can be comprised.

  In addition, in the example shown in FIG. 8, although the support | pillars 40 and 42 are each provided with six each on both surfaces, these numbers can be changed suitably. Moreover, it is preferable to arrange the same number at equal intervals, but it is not essential and the number may be different on both sides. In any of the embodiments in FIGS. 7 and 8, the shapes of the support columns 30, 32, 40, and 42 can be arbitrarily determined. In these embodiments, a square plate shape or a prism shape is used, but a cylindrical shape, a sector shape, or the like may be used.

  FIG. 9 is a diagram for explaining still another configuration example of the perforated disk 48 and the column 50. The perforated disk 48 of this embodiment is provided with two circular recesses 54 having an inner diameter slightly larger than the outer diameter of the support column 50 on one annular end surface 52 thereof. As shown in the figure, the recess 54 is provided for fitting the support 50. When producing a support using these perforated disks 48 and struts 50, the struts 50 are respectively fitted into the recesses 54 of the plurality of perforated disks 48, and then the perforated circles integrated with the struts 50 are integrated. A baking process is performed by superposing the plates 48. Therefore, since the positional deviation of the support 50 is suppressed, there is an advantage that the manufacture of the support body becomes easier.

  In the above embodiment, the other annular end surface 56 of the perforated disk 48 can be provided with a recess similar to the recess 54. In this way, when the perforated discs 48 are overlapped, the recess of the annular end surface 56 has a positioning function, so that there is an advantage that the alignment becomes easy.

  FIG. 10 is a perspective view showing a configuration example using a long bar 60 that functions as a guide for determining a relative position in the radial direction of a plurality of perforated discs 58. In this embodiment, a through hole 62 for piercing the long rod 60 through the perforated disk 58 is provided, for example, in the intermediate portion in the circumferential direction of the two columns 64. For this reason, when the perforated discs 58 are overlapped, positioning is performed simply by inserting them into the long bar 60, so that there is an advantage that the alignment becomes easy.

  The through hole 62 is provided, for example, so that its center is located on the same circumference as the center of the end face of the support column 64. However, the through hole 62 may be located on the outer peripheral side or the inner peripheral side. . Moreover, even if it is provided with the same diameter as the support | pillar 64, it may be provided with a smaller diameter or a larger diameter. Further, in this embodiment, the through holes 62 are provided at two locations in the circumferential direction, but the alignment effect can be obtained even at one location. Also, there may be three or more locations. When the through holes 62 are provided at two or more places, it is preferable that the through holes 62 are evenly arranged in the circumferential direction, but it is not essential. In this embodiment, the long bar 60 has a columnar shape, but the cross-sectional shape is not limited to a circle, and may be an appropriate shape such as a rectangle. Further, in the above embodiment, the support column 64 may be provided integrally with the perforated disk 58, and is separately manufactured as shown in the embodiment shown in FIG. 1 and FIG. Also good.

  Further, the long bar 60 can be used as a constituent member as it is, but it can be removed and reused after positioning or after the firing process. When it is removed and reused after the firing process, the through-hole 62 may be made larger so as not to be joined during the firing process.

  As mentioned above, although this invention was demonstrated in detail with reference to drawings, this invention can be implemented also in another aspect, A various change can be added in the range which does not deviate from the main point.

It is a perspective view which shows the ceramic straight tube hole cylindrical support body of one Example of this invention. It is a perspective view which shows the structural example of the oxygen separation membrane using the support body of FIG. It is process drawing explaining the principal part of an example of the manufacturing method of the ceramic straight tube hole cylindrical support body of FIG. It is a perspective view which shows the perforated disc obtained by the manufacturing process of FIG. It is a perspective view which shows the support | pillar obtained at the manufacturing process of FIG. It is process drawing explaining the principal part of an example of the manufacturing method of the oxygen separation membrane shown in FIG. It is a perspective view which shows the structural example with which the perforated disc and the support | pillar were integrally provided. It is a perspective view which shows the other structural example with which the perforated disc and the support | pillar were integrally provided. It is a perspective view explaining the other example of the attachment aspect of the support | pillar to a perforated disc. It is a perspective view explaining the structural example using the elongate stick for guides.

Explanation of symbols

10: Ceramic straight tube hole cylindrical support, 12: Perforated disk, 14: Support column, 16: Through hole, 18: Annular end face

Claims (5)

A plurality of perforated plate-like parts made of ceramic each having a through-hole penetrating in the thickness direction in the inner peripheral part and continuous with a predetermined mutual interval in the thickness direction;
A plurality of ceramic coupling portions disposed between the annular end faces of the plurality of perforated plate-like portions at a predetermined mutual interval in the circumferential direction and connecting the plurality of perforated plate-like portions to each other; A ceramic straight tube hole cylindrical support for an oxygen separation membrane, characterized in that the whole is cylindrical. General formula Ln _1-x Ae _x MO ₃ (where Ln is at least one selected from lanthanoids, Ae is at least one selected from Sr, Ca, Ba, M is Fe, Mn, Ga, Ti, Co, Ni) , Al, In, Sn, Zr, V, Cr, Zn, Ge, Sc, Y, perovskite complex oxides represented by 0 ≦ x ≦ 1), stabilized zirconia, cerium oxide, these And at least one ceramic selected from a composite material of at least one of these and at least one selected from silicon oxide, silicon nitride, titanium oxide, and aluminum oxide The ceramic straight tube hole cylindrical support according to claim 1, which is made of a material.   The ceramic straight tube hole cylindrical support according to claim 1 or 2, wherein a distance between the plurality of perforated plate-like portions is in a range of 0.01 to 50 (mm).   The plurality of perforated plate-like portions are located coaxially, and the portion between the outer peripheral side cylindrical surface and the inner peripheral side cylindrical surface including their outer peripheral surface and inner peripheral surface is 20 to 95 (%) The ceramic straight tube hole cylindrical support according to any one of claims 1 to 3, wherein the porosity is in the range of.   5. An oxygen separation membrane, wherein a dense membrane made of a mixed conductor is fixed to the surface of the ceramic straight tube hole cylindrical support according to any one of claims 1 to 4.

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