JP2003326138A - End sealing method of porous ceramic hollow-fiber membrane - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an end sealing method of a porous ceramic hollow-fiber membrane which is easily produced, extremely low in leakage of gas and effectively used for gas separation. <P>SOLUTION: One end of the porous ceramic hollow-fiber membrane is immersed in an organic solvent solution of a polymer material in which a ceramic powder is highly dispersed, and then is immersed in a coagulation bath, thus the ceramic powder and the polymer material are attached to the end of the hollow-fiber membrane. A composite membrane composed of the ceramic powder and the polymer material is sintered, and the opening of the porous ceramic hollow-fiber membrane is closed, thus a deadend structure is formed. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for sealing an end portion of a porous ceramic hollow fiber membrane. More specifically, the present invention relates to a method for sealing an end portion of a porous ceramic hollow fiber membrane which is effectively used in a gas separation device or the like.

[0002]

2. Description of the Related Art Since porous ceramics have high chemical and thermal stability, they are expected to be used as a separation membrane or a support thereof in a process in which an organic separation membrane cannot be applied. Of the separation modules that use this porous ceramic hollow tube, those that are used at high temperatures are:
In order to prevent damage to the ceramics due to the difference in thermal expansion,
In some cases, one end of the porous ceramic hollow fiber is closed with a flange or the like to form a dead end structure (Japanese Patent Laid-Open No. 7-112111).
Issue).

As a method for closing one end, Japanese Patent Laid-Open No.
-226370 discloses a method of filling an opening with an inorganic adhesive and further coating the portion with glass to ensure airtightness, but the process is complicated and a separation functional layer is formed in the porous portion. However, there were problems such that the glass component was diffused to the functional layer side when forming the film, and if the glass component was kept at a temperature above the glass softening point for a long time, a leak was likely to occur.

Further, the present applicant has previously proposed a gas separation module using a composite of metal and ceramics as shown in FIGS. 1 and 2 (Japanese Patent Application No. 2000-347689).

In FIG. 1, one end side 2 of a porous ceramic tubular body 1 is inserted into a tubular metal member 3 and the other end side 2 is inserted into a closed metal member 4, and these insertion points are In and An embodiment in which the active metal brazing material 5 containing Ti is bonded is shown. A gas separation membrane 6 is formed on the surface of the non-bonded portion of the porous ceramics tubular body 1, and the porous ceramics tubular body 1 on which such a gas separation membrane 6 is formed is formed.
The tubular metal member 3 in which is inserted is joined to the metal support 8 by using a general-purpose metal brazing material 7 such as silver brazing, nickel brazing, gold brazing, and palladium brazing in addition to the active metal brazing material as described above. As this metal support, a general-purpose metal such as stainless steel can be used.

FIG. 2 is a sectional view showing a hydrogen separation device equipped with a gas separation module 11 formed by joining a plurality of such tubular metal members for inserting a porous ceramic tubular body with a metal support. There is. The gas separation module 11 is accommodated in a cylindrical container 12 in a suspended state, and the cylindrical container is separated by a metal support 8 into a to-be-processed gas supply section 13 and a separated gas extraction section 14. .

The gas to be treated containing hydrogen is introduced from the pipe 15 to the outside of the module 11 in the cylindrical container 12, and only hydrogen permeates the gas separation membrane 6 and the porous ceramics 1 and each porous of the module. The separated and purified hydrogen is taken out from the pipe 16 provided in the separated gas taking-out section 14 via the internal space of the ceramic tubular body 1. On the other hand, the gas that has not been purified is discharged from the pipe 17 provided in the processing target gas supply unit 13.

As shown in FIG. 2, since the gas separation module 11 is accommodated in the cylindrical container 12 in a suspended state, the porous ceramic hollow fiber membrane is damaged by the weight of the closed metal member. There is a possibility.

[0009]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for sealing an end portion of a porous ceramic hollow fiber membrane which is easy to manufacture, has extremely little gas leakage, and is effectively used for gas separation. is there.

[0010]

The object of the present invention is as follows.
One end of the porous ceramic hollow fiber membrane is immersed in a solution of a high-dispersion ceramic powder in an organic solvent, and then immersed in a coagulation bath to form a ceramic powder adhered to the end of the hollow fiber membrane. This is achieved by sintering a composite membrane made of a polymer substance to form a dead end structure in which the openings of the porous ceramic hollow fiber membrane are closed.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION As a porous ceramics hollow fiber membrane whose one end is closed, an oxide ceramics such as alumina, silica, mullite, zirconia or a tubular body such as porous glass is used.

As the organic solvent solution of the polymer substance which is highly filled with the ceramic powder, the following combinations are used, for example.

The ceramic powder highly dispersed in an organic solvent solution of these polymer substances has, for example, a particle size of 0.1.
At least one kind of oxide ceramics having a particle size of ˜5 μm, preferably 0.2 to 1 μm, such as alumina, silica, mullite, and zirconia is used.

The stock solution for film formation is obtained by adding a ceramic powder that occupies 15 to 50% by volume in the finally prepared stock solution for film formation to an organic solvent solution of a polymer substance adjusted to a concentration of about 3 to 20% by weight. It is obtained by adding.

Next, one end of the porous ceramic hollow fiber membrane is immersed in the prepared membrane-forming raw material solution and then put into a coagulation bath of water or the like to form a composite membrane so as to close the opening by phase separation. After being formed, if necessary, it is heated at about 500 to 700 ° C. to decompose the polymer material, and further sintered. Sintering is performed on the end part where the composite film is formed,
It takes place at the sintering temperature of the ceramic powder used,
For example, when alumina is used as the ceramic powder, it is 1500 to 1750 ° C. for 2 to 24 hours, preferably 1650 to 1
It is carried out by heating at 700 ° C for 6 to 12 hours. If the sintering temperature is lower than this, it is not possible to ensure sufficient airtightness of the closed part, and even if the sintering time is shorter than this, it is possible to ensure sufficient airtightness of the closed part. Can not. Further, the sintering can be performed only at the end portions of the hollow fiber membranes, but can also be performed at the same time as the work of densifying the portions of the porous ceramics hollow fiber membranes other than those used as the separation functional layer.

[0016]

According to the present invention, there is provided a method for sealing an end portion of a porous ceramic hollow fiber membrane which is easy to produce, has extremely little gas leakage even under high temperature and high pressure, and is effectively used for gas separation. The porous ceramic hollow fiber membrane whose ends are sealed as described above is effectively used for producing a gas separator used for selectively separating hydrogen gas from hydrogen-containing gas.

Further, the above operation can be performed simultaneously with the operation of densifying and hermetically sealing the portion of the porous ceramic hollow fiber membrane other than the portion where the separation functional layer is formed, so that the operation time is greatly shortened. It is possible to plan.

[0018]

EXAMPLES The present invention will now be described with reference to examples.

Example A 20 g of polysulfone (P-1700 manufactured by Union Carbide) was mixed with 350 g (24% by volume) of alumina fine powder (average particle size 0.3 μm) and 250 g of dimethylformamide to prepare a stock solution for film formation. In this membrane forming solution, a porous alumina hollow fiber membrane (outer diameter 2.0 mm, inner diameter 1.4 mm, length 300 mm, average pore diameter 0.2 μm,
Approximately 5 mm at one end with a surface aperture ratio of 44% measured by a photograph was immersed for several seconds and then immersed in water as a coagulation bath to form a composite membrane of polysulfone and alumina fine powder on the end of the hollow fiber membrane.
Approximately 50 on one end including the end where the composite film was formed in this way
mm was inserted into an electric furnace and heated at 1650 ° C. for 12 hours for sintering. About 50 mm of one end of the sintered body was densified and its end was closed.

Approximately 50 mm, which is densified and has closed ends
When the helium leak amount was measured by cutting it out, the leak amount was less than 1 × 10 ⁻¹⁰ Pa · m ³ / s, and high gas tightness was exhibited.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of one embodiment of a metal-ceramic bonding body.

FIG. 2 is a vertical cross-sectional view of a gas separation device using a gas separation module.

[Explanation of symbols]

1 Porous ceramic tubular body 3 Tubular metal members 4 Blocking metal member 5 Active metal brazing material 6 Gas separation membrane 7 General-purpose metal brazing material 8 Metal support 11 Gas separation module 12 cylindrical container 13 Processed gas supply unit 14 Separation gas extraction part

Claims (3)

[Claims] 1. One end of the porous ceramic hollow fiber membrane is
After immersing the ceramic powder in a highly dispersed organic solvent solution of a polymer substance, immerse it in a coagulation bath to sinter the composite film consisting of the ceramic powder and polymer substance attached to the end of the hollow fiber membrane. And a dead end structure in which the opening of the porous ceramics hollow fiber membrane is closed, and a method for sealing the end portion of the porous ceramics hollow fiber membrane. 2. About the end where the sintering forms a composite film
It is performed under the condition of 1500 to 1750 ° C. and 2 to 24 hours.
The method for sealing an end portion of the porous ceramic hollow fiber membrane described. 3. A gas separation device using the end-sealed porous ceramics hollow fiber membrane obtained by the method according to claim 1.