JP3821019B2 - Ceramic hollow fiber membrane module - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a ceramic hollow fiber membrane module that can effectively prevent breakage due to distorted thermal deformation.
[0002]
[Prior art]
Composite hollow fiber membrane obtained by dry-wet spinning using a spinning stock solution in which ceramic powder such as Al ₂ O ₃ , SiO ₂ , ZrO ₂ is highly filled in an organic solvent solution of a polymer material having film-forming properties. A technique for producing a porous ceramic hollow fiber membrane having a pore diameter of about 0.1 to 6.0 μm and an outer diameter of about 0.5 to 4.0 mm by firing is known (Japanese Patent Publication No. 5-66343).
[0003]
Such a hollow fiber membrane made of porous ceramics can be used alone or as a filtration membrane for water treatment, etc., but it can be used as a support and a functional separation layer such as a Pd membrane layer or a silica layer on the surface of the hollow fiber membrane. It is also possible to use them by combining them so as to function as a gas separation membrane. In that case, a hollow fiber membrane module is formed in a state where about 1 to several hundreds of hollow fiber membranes are bundled and accommodated inside a bundled tube made of alumina or zirconia which is a long cylinder.
[0004]
In such a hollow fiber membrane module, it is possible to adopt a structure in which a bundling tube 21 containing a large number of hollow fiber membranes 25 is provided with one notch portion 27 for filling a bundling material at the center thereof (FIG. 6). . The hollow fiber membrane group is accommodated in the bundled tube by bundling the end portion of the hollow fiber membrane group through a flat plate 23 having a through hole 26 (hereinafter simply referred to as “eye plate”). The cutout portion 27 provided in the bundling tube 21 is provided to fill the baffle material into the eye plate portion from the inside. When such a hollow fiber membrane module is used as a gas separation membrane, the separation gas is supplied from one end side of the bundled tube, supplied, and exhausted from the other end side to circulate to separate into the hollow fiber membrane group. The gas is contacted and recovered after permeation.
[0005]
By the way, in such a bundling tube, the tube body is asymmetrical from the central axis because one half circumferential portion of the tubular body is cut out at the central portion in the longitudinal direction of the cylindrical shape. The tube bends or distorts in a convex shape with its cut-out part facing up, causing a misalignment between the end of the bundled tube and the eyepiece inserted therein, or due to a difference in thermal expansion coefficient. Due to the deformation caused by the generated thermal stress, the stress is locally concentrated on the member such as the eye plate and the module may be damaged.
[0006]
Further, in order to fix both ends of the hollow fiber membrane group in a sealed state to the eye plate, a glass sealing material is used as a bundling material. Generally, the glass sealing material is baked at 900 ° C. or higher. A heat treatment temperature is required. Since the temperature condition for using the hollow fiber membrane module is usually 300 to 350 ° C., when the coefficient of thermal expansion of the module component is set based on the temperature of 300 to 350 ° C., the firing temperature of the glass sealing material is 900 ° C. At such a high temperature, the difference in coefficient of thermal expansion between the members becomes large.
[0007]
As a result, in the firing process of the glass seal material, a positional shift occurs between the bundled tube and the hollow fiber group due to the difference in the coefficient of thermal expansion. Will cause residual stress. When a hollow fiber membrane module that has been manufactured with residual stress produced is provided for actual use, the module may be damaged by heating even within the module operating temperature range of 300 to 350 ° C.
[0008]
[Problems to be solved by the invention]
The purpose of the present invention is to structurally improve the bundled tube that bundles and accommodates a large number of porous ceramic hollow fiber membranes, thereby suppressing thermal deformation during use in a high temperature atmosphere and improving durability against breakage, etc. An object of the present invention is to provide a ceramic hollow fiber membrane module.
[0009]
[Means for Solving the Problems]
A ceramic hollow fiber membrane module according to claim 1 of the present invention is a bundle of a large number of hollow fiber membranes made of porous ceramics and accommodated in a long cylindrical bundled tube. Long cylindrical bundled tubes of porous ceramic hollow fiber membranes that are bundled in large numbers by providing gas supply / exhaust openings by cutting symmetrically equidistant portions on both sides with respect to the tube center axis. It is characterized in that the housing is carried out by a flat plate with a through hole for holding a hollow fiber membrane . Here, the symmetric equidistant position means that the openings are installed at equal intervals in the circumferential direction of the bundled tube, such as two, three, four, etc., without limiting the numerical aperture. ing.
[0010]
Moreover, the ceramic hollow fiber membrane module according to claim 2 is a case in which equidistant openings are provided on both sides in the vicinity of both ends of the bundled tube, and one end side is for gas supply. The other end side is for gas exhaust.
[0011]
In this case, it is only necessary to provide short hole openings for gas supply and gas exhaust in the vicinity of both ends of the bundled tube, so that the rigidity of the entire tube can be maintained or thermal deformation can be maintained. In addition, it can be set in consideration of workability when a hollow fiber membrane-holding through-hole flat plate that is a module constituent member called an eye plate is incorporated.
[0012]
Furthermore, the ceramic hollow fiber membrane module according to claim 3 is a case where openings are provided in a uniform long hole shape over substantially the entire length of the bundled tube, and gas is supplied from one end side thereof. It is possible to exhaust from the other end.
[0013]
In this case, by making the opening provided in the bundled tube into a long hole shape, the tube thickness in that range can be removed, so that the entire module can be reduced in weight, and at the same time, the efficiency of gas intake and exhaust can be improved, and The work of incorporating the hollow fiber membrane holding flat plate, which is a module component, is quick.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of a ceramic hollow fiber membrane module according to the present invention will be described in detail with reference to the drawings.
As shown in FIG. 1, the hollow fiber membrane module 1 accommodates a bundle of about 1 to 500 hollow fiber membranes 3 made of porous ceramics in a bundled tube 2 that is an elongated cylindrical body. A bundle group of the hollow fiber membranes 3 is held by being joined to a disc-shaped eye plate 5 at both ends 4 of the bundled tube 2.
[0015]
As shown in FIGS. 2 (a) to 2 (c), the bundling tube 2 is an elongated straight tube, and an elliptical shape is formed by cutting off symmetrical portions on both sides from the tube center axis in the vicinity of both ends. Or the short hole-shaped opening part 2a is bilaterally symmetrical, and a total of four are provided. However, the number of such openings 2a is not limited to four. In that case, the length of the short hole-shaped opening 2a is preferably 15 mm or more. The material of the bundling tube 2 is arbitrary as long as it is airtight and can be sealed with a bundling material. For example, an alumina tube, a zirconia tube, a titania tube, a silica tube, and a glass tube can be used.
[0016]
As shown in FIGS. 3 (a) to 3 (c), the bundled tube 2 has a structure shown in FIG. 2 as well as a symmetrical portion on both sides from the tube center axis in this case almost over the entire length of the tube. Two long hole-shaped openings 2b are provided symmetrically. The reason for providing the short hole-shaped opening 2a and the long hole-shaped opening 2b in this way is for gas supply / exhaust for bringing the separation gas into contact with and passing through the bundle group of the hollow fiber membranes 3, and at the same time, This is to improve workability when the eye plate 5 is incorporated and sealed. FIGS. 4A and 4B are examples showing a state in which a bundle group of the hollow fiber membranes 3 is accommodated in the bundled tube 2 in the case where the long hole-shaped opening 2b is provided.
[0017]
As described above, the gas supply / exhaust openings 2a or 2b are provided symmetrically at the symmetrical equidistant positions on both sides of the tube body in the bundled tube 2, thereby providing an unbalanced structure such as an asymmetric structure. It is possible to suppress the occurrence of bending and distortion due to thermal expansion as much as possible. That is, by suppressing the thermal deformation of the bundled tube 2, it is possible to prevent stress concentration from affecting other members such as the hollow fiber membrane 3, and to avoid a situation such as breakage of the module.
[0018]
On the other hand, the hollow fiber membrane 3 and the countersunks 5 at both ends, and the joints between these members such as the countersink 5 and the bundled tube end 4 are joined in a sealed state with a glass sealing material. As the glass sealing material, a firing temperature range of 600 to 700 ° C. in which the difference in coefficient of thermal expansion among the members of the bundling tube 2, the hollow fiber membrane 3 and the eye plate 5 falls within the range of ± 0.5 × 10 ⁻⁶ / ° C. A material that can be heat-treated is used.
[0019]
Therefore, as the hollow fiber membrane module 1, the thermal expansion of the entire module composed of each of the above members becomes uniform, and the generation of thermal stress due to the thermal expansion difference can be suppressed as much as possible. In addition, the glass sealing material firing process usually requires a heat treatment temperature of 900 ° C. or higher as described above. Here, a material that can be fired at 600 to 700 ° C. is selected. Therefore, the difference in thermal expansion between the members at the time of firing the glass seal can be minimized. Thereby, it is devised not to cause a positional shift between members, and the generation of residual stress after cooling is minimized.
[0020]
Concrete example:
As the bundling tube 2, for example, a tube provided with a long hole-shaped gas intake / exhaust opening 2 b shown in FIGS. 3A to 3C and FIGS. 4A and 4B is used. A piece made of alumina was used for the eye plate 5 joined so as to close the inside of the tube end 4. Nineteen hollow fiber membranes 3 with an outer diameter of 3 mm are inserted at both ends into a hole with a hole diameter of 3.6 mm provided through the eye plate 5, and a bundle of the 19 hollow fiber membranes 3 is bundled inside the bundled tube 2. Hold and set the group securely. A glass sealing material was applied to the joining portion between the end 4 of the bundled tube 2 and the eye plate 5 and fired at 700 ° C. to seal between the members, whereby the hollow fiber membrane module 1 was produced.
[0021]
The material of each member of the bundle tube 2, the hollow fiber membrane 3 and the eye plate 5 has a thermal expansion coefficient in the range of 7.4 × 10 ⁻⁶ / ° C. to 7.6 × 10 ⁻⁶ / ° C. at a firing temperature of 50 to 600 ° C. Alumina with a purity of more than 95.0% was used.
[0022]
Next, as shown in FIG. 5, this hollow fiber membrane module 1 was set in the leak evaluation test apparatus 10, and the gas leak test in the high temperature atmosphere was done. This test apparatus 10 is provided with a cylindrical container-shaped housing 11 made of SUS that accommodates the hollow fiber membrane module 1, and an intake pipe 12 and an exhaust pipe 13 that supply a separation gas project from both ends of the housing body. It has been. Although not shown, the intake pipe 12 communicates with a gas supply source. The exhaust pipe 13 is temporarily sealed, and the pressure is reduced by a vacuum pump so that the valve is closed and the pressure change is measured by a pressure gauge. It has become. Further, the opening portions at both ends of the body portion of the housing 11 are flanges 11a, which are closed by connecting the covers 14 and 15 of the lid members with bolts 16, respectively. The covers 14 and 15 at both ends are provided with permeate gas exhaust pipes 14a and 15a protruding outward from the center, and are used for piping for sending the gas that has permeated through the bundle group of the hollow fiber membranes 3 to a device outside the system. Communicate.
[0023]
In order to ensure the required airtightness in such an apparatus, an O-ring 17 is mounted as a seal material between the housing 11 and the end 4 on the hollow fiber membrane module 1 side accommodated therein, and the housing An O-ring 18 is also mounted between the body flange 11 a and the covers 14 and 15.
[0024]
In the gas leakage test, nitrogen gas ( N ₂ ) is supplied from the intake pipe 12 into the housing 11, introduced into the bundled pipe 2 from one end of the opening 2 b, and brought into contact with the bundle group of the hollow fiber membranes 3. Make it transparent. At that time, the pressure on the exhaust pipe 13 side is adjusted to 0.49 MPa, the permeate gas exhaust pipe 14a on one side of the housing is sealed, and the amount of nitrogen gas flowing out from the permeate gas exhaust pipe 15a on the other side of the housing is measured with a flow meter. taking measurement. The temperature was determined by heating the entire apparatus and nitrogen gas at 350 ° C., respectively.
[0025]
Rating:
As a result, it was confirmed that the hollow fiber membrane module 1 did not cause gas leakage after the heating test for 1 hour and was extremely airtight. In addition, regarding the problem of preventing thermal deformation of the bundled tube 2 which is the gist of the present invention, there is no tendency to bend or distort due to unbalanced thermal expansion, and it is a constituent member of the hollow fiber membrane module 1. It was confirmed that the hollow fiber membrane module 1 was excellent in heat resistance and thermal deformation suppression without any change in the bundled tube, the eye plate, etc., and without any positional displacement between the members. .
[0026]
【The invention's effect】
The ceramic hollow fiber membrane module according to the present invention has a gas supply / exhaust opening symmetrically provided on both sides of a bundled tube so that thermal expansion is balanced, and the opening is provided at an asymmetric position only on one side of the tube. As in the case where the module is provided, it is possible to eliminate the problem that the module is damaged by bending or distorting the bundled tube due to thermal stress caused by imbalanced thermal effects.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a hollow fiber membrane module configured by bundling and housing a large number of ceramic hollow fiber membranes in a bundled tube.
FIG. 2 is a perspective view (a), a side view (b), and a longitudinal sectional view (c) taken along line Y ₁ -Y ₁ showing a first embodiment of a bundled tube.
FIG. 3 is a perspective view (a), a side view (b), and a longitudinal sectional view (c) taken along line Y ₂ -Y ₂ showing a second embodiment of a bundled tube.
FIG. 4 is a side view (a) showing a state in which a bundle group of hollow fiber membranes is accommodated in a bundled tube of a second embodiment, and a longitudinal sectional view (b) taken from line Y ₃ -Y ₃ .
FIG. 5 is a cross-sectional view showing a mode in which a gas leak test is performed by setting the hollow fiber membrane module of the present embodiment in a leak evaluation test apparatus.
FIG. 6 is a perspective view of a hollow fiber membrane module in which a notch portion is provided at a central portion of a bundled tube.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Hollow fiber membrane module 2 Bundled tube 2a Short hole-shaped opening 2b Long hole-shaped opening 3 Hollow fiber membrane 4 Bundled tube edge part 5 Flat plate for hollow fiber membrane holding | maintenance 10 Leak evaluation test apparatus 11 Housing 12 Intake pipe 13 Exhaust pipes 14, 15 Housing cover
14a, 15a Permeate gas exhaust pipe

Claims (3)

A ceramic hollow fiber membrane module in which a number of hollow fiber membranes made of porous ceramics are bundled and accommodated in a long cylindrical bundled tube, and is symmetrically arranged on both sides with respect to the tube central axis of the bundled tube. Each part of the position is cut symmetrically to provide an opening , and a large number of bundled porous ceramic hollow fiber membranes are accommodated in a long tubular bundled tube by a hollow fiber holding through hole flat plate. ceramic hollow fiber membrane module, characterized in that cracking.   The ceramic hollow fiber membrane module according to claim 1, wherein openings are provided in a short hole shape with an equal distribution near both ends of the bundled tube.   2. The ceramic hollow fiber membrane module according to claim 1, wherein openings are provided in a uniform long hole shape over substantially the entire length of the bundled tube.

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