JPH0815537B2 - Method and apparatus for manufacturing ceramic separation membrane - Google Patents

Description

TECHNICAL FIELD The present invention relates to an ultrafine pore of several tens of liters for use when separating ultrafine particles of various bacteria present in the liquid region from the air. The present invention relates to a method and an apparatus for manufacturing a ceramic separation membrane for forming a ceramic.

Conventional technology In order to make a ceramic separation membrane with ultra-fine pores of several tens of liters as described above, it is possible to obtain ultra-fine particles with a uniform particle size of about 10 nanometers arranged regularly and firing them. Is expected, but it was impossible in practice. In the conventional manufacturing method and manufacturing apparatus of this kind, ceramic fine particles are compressed at a high pressure to form a porous plate, a solvent is applied to the surface of the porous plate, and it is fired. Is difficult to control and it is difficult to manufacture a precise separation membrane.

DISCLOSURE OF THE INVENTION PROBLEM TO BE SOLVED BY THE INVENTION As described above, an object of the present invention is to obtain a method and an apparatus for producing a ceramic separation membrane having ultra-fine pores of several tens of liters, which has heretofore been considered impossible to produce. .

Another object is to facilitate the control of the fine pore size generated when firing the fine particles, and as a result obtain a precise separation membrane.

Means for Solving the Problems The method for producing a ceramic separation membrane of the present invention is to charge the ultrafine particles of ceramic produced in a CVD reaction tube between a creeping discharge electrode and an electrode for particle migration, and to charge the charged ultrafine particles. Electrostatically adhered to the surface of the porous sintered body disposed near the electrode for particle migration between the both electrodes to form a porous ultrafine particle deposition layer, and the ultrafine particle deposition layer as it is By heating, a porous ultrafine particle sintered film is formed on the surface of the porous sintered body.

The apparatus for producing a ceramic separation membrane of this invention is an ultrafine particle generator equipped with a CVD reaction tube on the upstream side of the flow of a CVD reaction gas, and an electrostatic component consisting of a creeping discharge electrode and a particle migration electrode on the downstream side. A membrane device and a firing device are provided,
The creeping discharge electrode is formed by a planar induction electrode embedded in the thickness of the alumina porcelain layer and a linear electrode formed on the surface of the alumina porcelain layer, and a high-frequency high-voltage power supply is connected between these electrodes. Further, a direct current high voltage power source is connected between the creeping discharge electrode and the particle migration electrode.

Action The CVD reaction gas is supplied to the ultra-fine particle generator equipped with the CVD reaction tube, and the ultra-fine particles of the ceramic produced therein are supplied to the electrostatic film-forming device, and the creeping discharge electrode provided therein is While being charged by the surface corona discharge, it is driven toward the particle migration electrode by the DC electric field between the surface discharge electrode and the particle migration electrode, and the porous sintered body is placed in front of the particle migration electrode in advance. Deposit on the surface of the body to form a porous ultrafine particle deposition layer. After that, in a state where the porous ultrafine particle deposition layer is deposited on the surface of the porous sintered body, it is heated by a firing device such as an electric furnace to generate a porous ultrafine particle sintered film to form a ceramic separation membrane. It is manufactured.

EXAMPLE An example of the method and apparatus of the present invention will be described with reference to the accompanying drawings. Ultrafine particles having a CVD reaction tube 2 and a heater 3 on the upstream side of the flow of a reaction gas 1 as shown in FIGS. 1 and 2. A generator 4 is provided, and the reaction gas 1 is supplied into the CVD reaction tube 2 together with the sheath gas 1a, and ultrafine particles p of, for example, silicon nitride generated therein are beam 1b as shown in the figure.
Then, the particles are supplied to the space between the creeping discharge electrode 5 and the particle migration electrode 6 in the electrostatic film forming device 7 provided on the downstream side of the ultrafine particle generating device 4. Further, the creeping discharge electrode 5 is embedded in the alumina porcelain layer 9 and the rod-shaped induction electrode 10 and the coil formed on the outer surface of the alumina porcelain layer 9 (pitch 2-3 m
m) shaped linear electrode 11 and a high frequency high voltage power supply 12 is connected between these electrodes 10 and 11, and a high frequency high voltage (10KHZ, 15KHZ) is applied between them, the surface of the creeping discharge electrode 5 A high-density AC creeping corona is generated in the vicinity. At this time, positive and negative ions are mixed in the AC creeping corona, but a DC high voltage (1.5 kv to 0.5 kv) is applied between the creeping discharge electrode 5 and the particle migration electrode 6 by the DC high voltage power supply 13. Then, according to the polarity, positive or negative unipolar ions only can be taken out in the vicinity of the surface of the creeping discharge electrode 5, and the particles passing through this vicinity are efficiently charged to unipolar. Charged ultrafine particles p
Receives Coulomb force f due to the DC voltage, migrates in the radial direction from the central part of the device, and is deposited on the inner surface of the cylindrical porous sintered body 14 to form a porous ultrafine particle deposition layer 15.
Since the cylindrical sintered body 14 continuously moves upward or downward while slowly rotating in the direction of arrow A14, a uniform porous ultrafine particle layer 15 is formed on the inner surface thereof. The cylindrical porous sintered body 14 on which the ultrafine particle layer 15 is formed in this manner is fired by the firing device 8 provided on the outside thereof, and the ultrafine particles adjacent to each other are fired to form a ceramic having ultrafine pores. It becomes a separation membrane. The thickness of the separation membrane formed at this time is controlled by the concentration of ultrafine particles and the moving speed of the cylindrical sintered body 14. Further, the fine pore size of the separation membrane is controlled by the size of the ultrafine particles and the state of particle accumulation.

The size of the ultrafine particles is controlled by the generation conditions, and the deposition state of the particles in the process of forming the ultrafine particle deposition layer 15 is the corona ion density during the corona discharge and both electrodes 5,
Controlled by the DC voltage applied between 6.

The present invention has been described above with reference to the embodiments shown in FIGS. 1 and 2, but the present invention is not limited thereto and can be carried out by changing the concrete means within the scope of the constitution of the present invention. Is.

An example is shown in FIGS. 3 to 6, which comprises a silicon nitride ultrafine particle generation device 4, an ultrafine particle electrostatic film forming device 7, and a baking device 8 for the ultrafine particle sintered film 16. There is.

In the quartz tube 18, the ultrafine particles generated by the firing device 4 are transported to the electrostatic film deposition device 7 in the form of a cylindrical flow 1c and guided to the vicinity of the surface of the creeping discharge electrode 5. Here, the ultrafine particles are charged unipolarly, receive Coulomb force in the DC electric field formed between the creeping discharge electrode 5 and the particle migration electrode 6, migrate toward the center of the quartz tube 18, and support the sintered body. The ultrafine particle deposition layer 15 is formed by depositing on the outer surface of the cylindrical porous sintered body 14 previously supported in the center by the tool 17.

After that, the ultrafine particle deposition layer 15 deposited on the outer surface of the cylindrical porous sintered body 14 is moved to the sintering apparatus 8 as it is and sintered there.

The creeping discharge electrode 5 is composed of a linear electrode 11 and a planar induction electrode 10 provided via an insulator formed of a cylindrical alumina porcelain layer 9 as shown in FIGS. 4 to 6. Both electrodes
Both 10 and 11 are made of tungsten and have a thickness of 0.05 mm or less, and the inner linear electrode 11 has the shape shown in FIGS. 4 and 5.

When a high frequency high voltage is applied between the induction electrode 10 and the linear electrode 11 by the power source 12, a high-density AC creeping corona is generated near the surface of the linear electrode 11 on the inner surface.

Positive and negative ions are mixed in the AC creeping corona, but when a DC high voltage is applied between the linear electrode 11 and the rod-shaped particle migration electrode 6 installed in the center, the creeping is discharged according to the polarity. Only positive or negative positive unipolar ions can be taken out near the surface of the electrode 5, and the particles passing through this vicinity are efficiently charged to unipolar.

The charged ultrafine particles receive Coulomb force in the DC electric field,
It migrates toward the center of this device, adheres to the outer surface of the cylindrical porous sintered body 14, and forms a porous particle deposition layer 15.

At this time, the cylindrical sintered body 14 continuously moves upward or downward while slowly rotating in the direction of arrow A14, so that a uniform particle deposition layer 15 is formed on the outer surface thereof.

The cylindrical sintered body 14 on which the particle deposition layer 15 is formed moves to the firing device 8 as it is, and is fired there to form a ceramic film 16 having fine pores.

EFFECTS OF THE INVENTION The present invention is as described above, and the ultrafine particles produced by the CVD method are deposited on the surface of the cylindrical sintered body by the clonal force of the electrostatic film deposition apparatus and sintered in that state. Since the diameters are uniform, it is easy to control the thickness and the extremely fine pore diameter of the ceramic separation membrane after sintering. (See Attachment Reference Photo 1) It is possible to manufacture ceramic separation membranes of 10 Å, which has been considered impossible in the past, and excellent separation membranes can be easily formed.
(Refer to Reference Photo 2 separately.) Further, charged ultrafine particles swim in the gas phase by the clonal force, so their swimming activity is more than two orders of magnitude higher than their thermal swimming activity.

Furthermore, since the separation membrane obtained according to the present invention enables the separation of the membrane under severe conditions, the introduction of the separation membrane into a non-aqueous system such as petroleum, pharmaceuticals, food industry is realized, and in that case, It may replace high energy consuming distillation. Furthermore, it can be applied to bioreactors and new fields such as super constant temperature and supercritical.

Further, the charging characteristics, kinetic characteristics, etc. of the ultrafine particles are almost independent of the type of substance, and the present invention can be applied to almost all ultrafine particles such as alumina, titanium oxide, zirconia, silicon nitride and silica. .

[Brief description of drawings]

FIG. 1 is a front view of an embodiment of the present invention, FIG. 2 is an enlarged cross-sectional view of an essential part thereof, FIG. 3 is a front view of another embodiment, and FIG. 4 is a IV-IV line portion of FIG. Fig. 5 is a developed view of the V-V line of Fig. 4, Fig. 6 is an enlarged cross-sectional view of a part of Fig. 1 1 ... Reactive gas 2 ... CVD reaction tube 4 ... Ultra Particle generation device 5 …… Creepage discharge electrode 6 …… Particle migration electrode 7 …… Electrostatic film deposition device 8 …… Firing device 9 …… Alumina porcelain layer 10 …… Induction electrode 11 …… Linear electrode 12 …… High frequency Voltage power supply 13 …… DC high voltage power supply 14 …… Porous sintered body 15 …… Ultra fine particle deposition layer 16 …… Ultra fine particle sintered film

Claims (8)

[Claims] 1. Ceramic ultrafine particles generated in a CVD reaction tube are charged between a creeping discharge electrode and a particle migration electrode, and the charged ultrafine particles are located between the two electrodes and close to the particle migration electrode. The surface of the porous sintered body is electrostatically adhered to the surface of the porous sintered body to form a porous ultrafine particle deposition layer, and the ultrafine particle layer is heated as it is to form a porous layer on the surface of the porous sintered body. For producing a ceramic separation membrane, characterized by producing a high quality ultra fine particle sintered membrane 2. A creeping discharge electrode is composed of a linear electrode and an induction electrode arranged via an alumina porcelain layer, and a particle migration electrode is provided so as to face the linear electrode. The method for producing a ceramic separation membrane according to claim 1. 3. A creeping discharge electrode is composed of a rod-shaped induction electrode and a linear electrode formed on the outer periphery thereof through an alumina porcelain layer, and a particle migration electrode is formed in a circular tube shape, and the creeping surface is formed at the center thereof. The method for producing a ceramic separation membrane according to claim 1, wherein a discharge electrode is provided. 4. A creeping discharge electrode is composed of a planar induction electrode embedded in the thickness of a cylinder made of alumina porcelain and a linear electrode formed on the outer surface of the cylinder, and a high frequency high voltage is provided between these electrodes. The method for producing a ceramic separation membrane according to claim 1, wherein a power source is connected. 5. A creeping discharge device embeds a planar induction electrode within the thickness of a cylindrical alumina porcelain layer, forms a linear electrode on its inner peripheral surface, and supplies a high-frequency high-voltage power supply between these electrodes. 2. The method for manufacturing a ceramic separation membrane according to claim 1, wherein the separation membranes are connected. 6. An ultrafine particle generator equipped with a CVD reaction tube on the upstream side of the flow of a CVD reaction gas, an electrostatic film forming apparatus comprising a creeping discharge electrode and a particle migration electrode, and a baking apparatus on the downstream side thereof. Each of the surface discharge electrodes is provided by embedding the creeping discharge electrode in the thickness of the alumina porcelain layer and a linear electrode formed on the surface of the alumina porcelain layer, and a high frequency wave is placed between the electrodes. A high-voltage power supply is connected, and a direct-current high-voltage power supply is connected between the creeping discharge electrode and the particle migration electrode. 7. A creeping discharge electrode comprises a rod-shaped induction electrode and a linear electrode formed on the outer periphery of the rod-shaped induction electrode via an alumina porcelain layer,
A high-frequency high-voltage power supply is connected between the both electrodes, and the apparatus for producing a ceramic separation membrane according to claim 6. 8. A creeping discharge electrode comprises a planar induction electrode embedded in the wall thickness of a cylinder made of alumina porcelain and a linear electrode formed on the inner surface of the cylinder. 7. The apparatus for producing a ceramic separation membrane according to claim 6, wherein a power source is connected.