JP2009082881A - Manufacturing method for glass-sealed porous ceramic hollow thread - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method for a glass-sealed porous ceramic hollow thread effectively prevent deflection of the porous ceramic hollow thread penetrated through a support made of ceramic or the like from being generated by gravity force at heating of a glass material when glass sealing covering layers are provided at both end sides of the porous ceramic hollow thread penetrated through the support made of ceramic or the like. <P>SOLUTION: When outer surfaces at both end sides of the porous ceramic hollow thread which keeps the support penetrated in the inner pipe part are coated with a glass material and calcination is performed to form the glass sealing covering layers, and both ends of the support projected from both ends of the porous ceramic hollow thread placed on the base, further a heavy weight substance is superposed on the base, and calcination of the glass material is performed in the bridge form that both ends of the support are fixed. Thereby, the glass sealing porous ceramic hollow thread is manufactured. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for producing a glass-sealed porous ceramic hollow fiber. More specifically, the present invention relates to a glass-sealed porous ceramic hollow fiber with little warpage when forming a glass sealing portion.

  Since the porous ceramic hollow fiber has high chemical stability and thermal stability, the porous ceramic hollow fiber is used as a separation membrane for processes in which an organic separation membrane cannot be applied. Further, by using a porous ceramic hollow fiber as a support and forming a functional separation layer such as a silica layer on the surface of the hollow fiber membrane, it is also used as a gas separation membrane.

  Thus, in the separation membrane using the porous ceramic hollow fiber as a support, a functional separation layer is formed on the surface of the support and has a function of transmitting a specific component depending on the specific component or its size. The region where the functional layer is formed is limited, and the other portions need to be hermetically sealed so as not to allow fluid to pass therethrough.

In order to prevent this airtightness, a glass material, for example, a glass frit forming a pasty glass material dispersed in a suitable organic solvent is applied to the sealing portion, dried, and then the softening point of the glass material. A method of glass sealing by heating as described above has been proposed.
JP-A-11-226370

  Various types of glass frit used here are selected depending on the environment to be separated. In particular, in an environment where gas separation is performed at a high temperature, high heat resistance is also required for the glass sealing portion. And since glass with high heat resistance also has a high softening point as a whole, the heating at the time of glass sealing also becomes high temperature. However, when heating is performed at a high temperature, warping and undulation occur, making it difficult to obtain a straight porous ceramic hollow fiber.

  When warping or undulation occurs in the obtained porous ceramic hollow fiber, the number of porous ceramic hollow fibers filled in the module is limited, so compared with a module using a straight porous ceramic hollow fiber, There is a problem that the membrane surface area per unit volume is reduced.

As a countermeasure for this, a method has been proposed in which a porous ceramic hollow fiber is inserted into a ceramic tube having an inner diameter larger than its outer diameter and heated, thereby suppressing warpage and undulation. However, even if this method is effectively applied when the surface of the inner tube portion of the porous ceramic hollow fiber is sealed with glass, the glass material is used when the outer surface of the porous ceramic hollow fiber is sealed with glass. There is a problem of sticking to the ceramic tube.
JP-T 8-507896

In contrast to this, when a film-forming stock solution made of an organic solvent solution of a film-forming substance filled with ceramic powder or the like is formed into a dry and wet film, and the resulting composite film is fired, the tube portion in the composite film can withstand the firing temperature. A method for producing a porous ceramic hollow fiber in which a ceramic support is inserted and fired has been proposed prior to the present applicant.
JP 2002-253937 A

  When the glass sealing coating layers are provided on both ends of the thus produced porous ceramic hollow fiber, both ends of the ceramic support are removed without firing the ceramic support from the porous ceramic hollow fiber after firing. It is necessary to prevent the coated glass material from coming into contact with other objects by placing the part on a table and covering it as a bridge. Although this suppresses large warping and undulation, the porous ceramic hollow fiber inserted through the ceramic support during heating of the glass material is slightly bent by gravity, and the resulting glass-sealed coating layer-forming porous ceramic hollow fiber is obtained. The actual situation is that it cannot be avoided that some deflection occurs.

  The object of the present invention is to provide a porous porous ceramic hollow fiber through which a ceramic support is inserted when the glass sealing coating layer is provided on both ends of the porous ceramic hollow fiber through which the ceramic support is inserted. An object of the present invention is to provide a method for producing a glass-sealed porous ceramic hollow fiber in which the ceramic hollow fiber is effectively prevented from being bent due to gravity.

  The object of the present invention is to apply a glass material to the outer surfaces of both ends of a porous ceramic hollow fiber having a support inserted through an inner tube portion, and to form a glass sealing coating layer by firing. Put both ends of the support projecting from both ends of the ceramic hollow fiber on a table, and stack the heavy objects on the table and fire the glass material in a bridge shape that fixes both ends of the support to seal the glass This is achieved by a method for producing a porous ceramic hollow fiber.

  The glass-sealed porous ceramic hollow fiber produced by the method of the present invention can significantly reduce the amount of deflection of the porous ceramic hollow fiber during heating for forming the glass sealing coating layer. The method of the present invention can be equally applied to cases other than the case where a glass sealing coating layer is formed on the outer surfaces of both ends of the porous ceramic hollow fiber, for example, a coating layer having other functions at a firing temperature of 1000 ° C. It is also effectively applied to the formation of

  The porous ceramic hollow fiber in which the support is inserted into the inner tube portion is obtained in the method described in Patent Document 3 in a state where the ceramic support is not removed after firing. Alternatively, even when a ceramic support is inserted through the inner tube portion of the porous ceramic hollow fiber that has already been formed, a product in such a state can be obtained.

  As the porous ceramic hollow fiber, one having an outer diameter of about 2.5 to 3.3 mm, an inner diameter of about 1.8 to 2.8 mm, and a length of about 200 to 450 mm is used. One having an outer diameter corresponding to about 50 to 90%, preferably about 60 to 70% of the inner diameter of the porous ceramic hollow fiber has a length of one protruding portion protruding from both ends of the porous ceramic hollow fiber. Used in a state of about 10-50 mm.

  The porous ceramic hollow fiber before or after the support is inserted is formed with a glass sealing coating layer with a required length on the outer surface on both ends, for example, about 50 to 200 mm. For example, a glass paste in which glass frit is dispersed in an organic solvent is applied by any application means such as dipping, spraying, brushing, etc., and the glass material is baked to form a glass sealing coating layer To form.

  As described above, the support made of ceramic or the like has a length that protrudes from both ends of the porous ceramic hollow fiber, and both ends of the support protruded from both ends of the porous ceramic hollow fiber are The glass material is fired in the form of a bridge which is placed on a table and further piled up heavy objects on the table and fixed at both ends of the support.

  Both the table on which both ends of the support are placed and the heavy object used on the table must have heat resistance that can withstand the heating temperature of about 1000 to 1400 ° C., which is the firing temperature of the glass material. From these viewpoints, it is preferable that both are made of ceramics. In addition, these platforms and heavy objects are generally provided with grooves for fitting a round bar-like or cylindrical support, preferably a groove with a semicircular cross section.

  In the case where the porous hollow fiber, support, base, heavy object, etc. are made of ceramics, they are made of alumina, silica, zirconia, spinel magnesia, etc., and generally those made of alumina are used. Further, when heating is performed in an inert atmosphere, the support, the table, and the heavy object may be made of a refractory metal that can withstand a firing temperature such as tungsten. The specific gravity of ceramics or the like that forms a heavy object is the same as or higher than that of ceramics or the like that forms a table. In addition, the weight of the heavy object is generally the same as or more than the weight of the table.

  Next, the present invention will be described with reference to examples.

Example: A glass frit (Nippon Electric Glass Product GA-33) with a length of 60 mm on each outer surface of both ends of a porous alumina hollow fiber having an outer diameter of 3.0 mm, an inner diameter of 2.2 mm, and a length of 350 mm was used as a solvent (Kanto Chemical). A glass paste (glass frit concentration 40% by weight) dispersed in the product terpineol) was applied and dried at room temperature. Thereafter, an alumina round rod having a diameter of 1.7 mm and a length of 450 mm is inserted as a support into the inner tubular portion of the porous alumina hollow fiber, and an alumina round rod having a length of 50 mm from each end of the porous alumina hollow fiber. Protruded.

  The alumina round bar support was placed on a 40 × 80 × 15 mm rectangular alumina platform, and an alumina heavy product of the same size and shape was placed on the platform. Each of these rectangular alumina bases and heavy objects is provided with a semicircular cross-sectional groove portion for fitting the support body to a portion in contact with the longitudinal support body.

  The support-inserted porous alumina hollow fiber thus bridged by fixing both ends of the support in this way was heated at 1300 ° C. for 1 hour to form a glass sealing coating layer. After cooling, the support was taken out and the amount of warpage in the half-length portion of the porous alumina hollow fiber was measured and found to be 0.1 mm or less.

Comparative Example In the example, the support-inserted porous alumina hollow fiber formed into a bridge shape without placing the alumina heavy product on the alumina table was subjected to the same heating to form a glass sealing coating layer. When the amount of warpage in the half length portion of the porous alumina hollow fiber was measured, the amount of warpage was 2 mm.

Claims (4)

  When a glass material is applied to the outer surface of both ends of the porous ceramic hollow fiber with the support inserted through the inner tube and fired to form a glass sealing coating layer, both ends of the porous ceramic hollow fiber are Glass-sealed porous ceramics characterized in that a glass material is fired in a bridge shape in which both ends of the projecting support are placed on a table, and a heavy object is stacked on the table to fix both ends of the support. Hollow fiber manufacturing method.   2. The method for producing a glass-sealed porous ceramic hollow fiber according to claim 1, wherein a base on which both ends of the support are mounted and a groove for fitting the support to a heavy object stacked on the base are provided. .   The method for producing a glass-sealed porous ceramic hollow fiber according to claim 1, wherein the support is a ceramic support.   The method for producing a glass-sealed porous ceramic hollow fiber according to claim 1 or 2, wherein both the stage on which both ends of the support are mounted and the heavy object stacked on the stage are made of ceramics.