KR101146137B1 - Oxygen permeable tube and Manufacturing method thereof - Google Patents

Abstract

The present invention is a porous support consisting of two or more porous layers having different porosity; And an oxygen separation tube coated on the inner wall of the porous support and separating the oxygen in the air passing through the inside of the porous support, thereby preventing damage to the oxygen separation membrane and forming oxygen permeability and oxygen separation membrane. Ease of use can be secured at the same time.
According to another aspect of the present invention, there is provided a method of manufacturing a porous support including two or more porous layers having different porosities; Filling an oxygen separation membrane coating solution into the porous support; Forming an oxygen separation membrane on the inner wall of the porous support by remaining the oxygen separation membrane coating solution in the porous support for a predetermined time; Discharging the remaining oxygen separation membrane coating solution from the porous support; Drying the porous support on which the oxygen separation membrane is formed; And calcining the porous support on which the dried oxygen separation membrane is formed, thereby forming a uniform and dense oxygen separation membrane to improve oxygen separation performance of the oxygen separation tube. Can be.

Description

Oxygen permeable tube and manufacturing method

The present invention relates to an oxygen separation tube coated with an oxygen separation membrane on the inner wall of the porous support and a method of manufacturing the same. More specifically, the oxygen separation membrane is formed on the inner wall of the porous support made of a plurality of porous layers having different porosities. An oxygen separation tube and a method of manufacturing the same.

Recently, as interest in the environment and energy has increased, research on oxygen separation membranes has been actively conducted. The oxygen separation membrane extracts only pure oxygen from the air, and is widely used in ammonia synthesis, other synthetic chemical industries, metallurgy, metal welding and cutting.

Oxygen separation membranes are those in which oxygen is separated from air by the selective transmission principle of oxygen to the membrane. That is, oxygen among the various components in the air is selectively bonded to the oxygen separation membrane and separated into oxygen ions and electrons. The separated oxygen ions and electrons are moved through the oxygen separation membrane, respectively, and the transferred oxygen ions and the electrons are combined again to release oxygen molecules to the outside of the oxygen separation membrane to separate pure oxygen.

However, the oxygen separation membrane itself is difficult to be used alone because of its weak mechanical strength. Therefore, it was conventionally formed by coating a ceramic or metal oxide having an electron conductive property as an oxygen separation membrane on a gas permeable support. However, in the conventional oxygen separation membrane, since the oxygen separation membrane is manufactured to be exposed to the outside such as formed on the outer wall of the support, there is a problem that the oxygen separation membrane is easily damaged by soot during combustion or chemical reaction.

On the other hand, the spray method is mainly used as a conventional method for coating the oxygen separation membrane on the support. However, when forming the oxygen separation membrane by the spray coating method, there was a problem that it is difficult to control the thickness or flatness of the oxygen separation membrane.

In addition, the oxygen transmission rate of the oxygen separation membrane is known to increase in inverse proportion to the thickness of the separation membrane, but when using the spray coating method, there is a problem that the oxygen separation membrane is thickened to decrease the oxygen transmission rate, and as a result, the efficiency of the chemical process decreases. .

The present invention is to prepare a porous support composed of two or more porous layers having different porosity so that the oxygen separation membrane can be formed dense and easily, and hollow shape to prevent damage to the oxygen separation membrane in the combustion and chemical reaction process An oxygen separation tube coated with an oxygen separation membrane on an inner wall of the porous support may be provided, and a method of manufacturing the same.

The present invention is a porous support consisting of two or more porous layers having different porosity; And it is coated on the inner wall of the porous support, and provides an oxygen separation tube comprising an oxygen separation membrane for separating the oxygen in the air passing through the interior of the porous support.

According to another aspect of the present invention, there is provided a method of manufacturing a porous support including two or more porous layers having different porosities; Filling an oxygen separation membrane coating solution into the porous support; Forming an oxygen separation membrane on the inner wall of the porous support by remaining the oxygen separation membrane coating solution in the porous support for a predetermined time; Discharging the remaining oxygen separation membrane coating solution from the porous support; Drying the porous support on which the oxygen separation membrane is formed; And it provides a method for producing an oxygen separation tube comprising the step of firing the porous support on which the dried oxygen separation membrane is formed.

According to the present invention, the oxygen separation membrane of the oxygen separation tube can be prevented from being damaged in the combustion and chemical reaction processes, and the oxygen separation membrane can be easily, precisely and uniformly formed, thereby improving the oxygen separation performance of the oxygen separation tube. You can.

Figure 1 is a photograph of the inside of the oxygen separation tube observed with an electron microscope (SEM).
Figure 2 is a schematic diagram showing an example of a porous alumina support fabrication process.
3 is a schematic view showing an example of an oxygen separation membrane formation process.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

However, embodiments of the present invention may be modified in various other forms, and the scope of the present invention is not limited to the embodiments described below. In addition, the embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art.

Hereinafter, first, the oxygen separation tube of the present invention will be described in detail.

The oxygen separation tube of the present invention includes a porous support made of a porous layer having different porosities and an oxygen separation membrane formed on an inner wall of the porous support.

The porous support is to support the oxygen separation membrane, it may have a hollow shape.

The inside of the hollow of the porous support is a passage through which air passes, and the air introduced into the hollow is in contact with the oxygen separation membrane formed on the inner wall of the porous support, and oxygen in the contacted air is separated by the oxygen separation membrane, The pores will escape to the outside.

Specifically, oxygen in the air in contact with the oxygen separation membrane is reduced to an oxygen ion through the reaction as shown in the formula (1) to become oxygen ions.

[Formula 1]

^{_{½O 2 (g) + 2e -}} → O 2 -

The oxygen ions are oxidized as shown in the following Chemical Formula 2 through the oxygen separation membrane to generate oxygen molecules.

[Formula 2]

^{_{O 2 - → ½O 2 (g}} ) + 2e -

The generated oxygen molecules pass through the support and exit to the outside through the pores of the porous support.

On the other hand, when the porous support is made of one porous layer having a high porosity, there is an effect of obtaining oxygen permeability, but the surface of the support by the pores may be difficult to form the oxygen separation membrane itself.

Therefore, the porous support of the present invention is characterized by consisting of two or more porous layers having different porosities. At this time, it is preferable that the porosity of the porous layer at the innermost part of the porous support is lower than that of the other porous layers.

In other words, it is effective to secure the oxygen permeability of the porous layer except for the porous layer located at the innermost part of the porous support to secure oxygen permeability, but the porous layer located at the innermost part of the porous support becomes the inner wall of the support. Since the oxygen separation membrane is coated, a relatively low porosity may be advantageous in forming a membrane by preventing roughness of the surface.

In particular, the porosity of the porous layer located on the innermost side of the porous support is more preferably 2 to 18 vol%. If the porosity is less than 2 vol%, the porosity is too small, and even though the porous layer is made thin, oxygen is difficult to pass. If the porosity exceeds 18 vol%, surface roughness of the porous layer is generated, which makes it difficult to form an oxygen separation membrane. Where vol% is in percent of the pore volume relative to the tube volume.

On the other hand, the porosity of the porous layer other than the porous layer located at the innermost portion of the porous support is more preferably 20 to 50 vol%. When the porosity is less than 20 vol%, oxygen that has passed through the oxygen separation membrane may not easily exit the porous support. In addition, when the porosity exceeds 50 vol%, the mechanical strength of the porous support may be weakened.

On the other hand, the porous support comprises at least one of a metal oxide, a ceramic or a combination thereof and distilled water, the metal oxide, ceramic or a combination thereof gives the mechanical strength and porous properties of the porous support, in particular alumina The permeability, mechanical strength, chemical stability and heat resistance of the separator are high, making it suitable as a material for the support.

In addition, the metal oxide, the ceramic or a combination thereof is more preferably a particle diameter of 0.5 to 1㎛. That is, by controlling the particle diameter of the metal oxide and the like in the above range, it is well dissolved in distilled water and well dispersed in the preparation of the porous support, which is advantageous for obtaining a desired porosity and more uniform pores.

On the other hand, the oxygen separation membrane is to separate the oxygen from the air, characterized in that formed on the inner wall of the porous support is formed. If the oxygen separation membrane is formed on the outer wall of the porous support, it is preferable that the oxygen separation membrane is formed on the inner wall of the support because it is easy to damage the oxygen separation membrane during combustion or during chemical processes.

At this time, the oxygen separation membrane may be formed of two or more layers. When the oxygen separation membrane is formed of a plurality of layers, the first oxygen separation membrane layer is preferably formed to be dense and uniform, and the oxygen separation membrane layer coated thereon has a somewhat bumpy curved surface. The surface area of the separator is widened to facilitate contact with air and the oxygen separation reaction is also active, thereby obtaining an oxygen separator having a more excellent effect.

In addition, the oxygen separation membrane preferably comprises a metal oxide, the metal oxide has the following formula (3).

(3)

BaCo _{1 -X- Y} A _X B _Y O _{3 + δ}

Where A and B are transition metals, generally metals belonging to the d-region of the periodic table. For example, La, Co, Sr, Mn, Al, Cr, Ga, Nb, Ti, Cu, Zn, Ga, etc. are mentioned. In addition, the metal oxide may be a structure of the perovskite consisting of the metals, the sum of X and Y in the formula (3) is 0 ≤ X + Y ≤ 1, δ value is preferably 2.7 ~ 3.3 .

Next, as another aspect of the present invention, a method for producing an oxygen separation tube will be described in detail.

Oxygen separation tube manufacturing method of the present invention comprises the steps of preparing a porous support consisting of at least two porous layers having different porosity; Filling an oxygen separation membrane coating solution into the porous support; Forming an oxygen separation membrane on the inner wall of the porous support by remaining the oxygen separation membrane coating solution in the porous support for a predetermined time; Discharging the remaining oxygen separation membrane coating solution from the porous support; Drying the porous support on which the oxygen separation membrane is formed; And firing the porous support on which the dried oxygen separation membrane is formed.

The step of preparing the porous support will be described with reference to FIG. 2. Figure 2 shows an example of the process from (i) to (iii), referring to Figure 2, the method for producing a porous support is (i) preparing a first slurry 101, (ii) Filling the first slurry 101 in the mold 102 and staying for a predetermined time to fix the first slurry 101 to the inner wall of the mold 102, (i) not sticking from the mold Discharging the remaining first slurry 101 to form the first porous layer 103, (i) preparing a second slurry 104 having a different ratio of the first slurry 101 to the pore-forming agent. Step (i) Filling the second slurry 104 in the forming mold 102 to which the first porous layer 103 is fixed and dwelling for a predetermined time so that the second slurry 104 is formed on the inner wall of the first porous layer 103. Fixing the slurry 104, (i) discharging the unfixed second slurry 104 from the first porous layer 103 to mold the second porous layer 105. Thereby forming a porous support 106 composed of an outer first porous layer 103 and an inner second porous layer 105, (iii) drying the formed porous support 106, (iii) Firing the dried porous support 106.

Hereinafter, each step will be described in detail.

First, the slurry may be prepared by mixing at least one of metal oxides, ceramics or combinations thereof, distilled water, pore formers and dispersants.

Specifically, at least one of the metal oxide, ceramic, or a combination thereof is preferably included in the slurry of 14 to 34% by weight. If it is less than 14% by weight, the mechanical strength of the porous support is weakened, and thus, the support may not function properly. If the content is more than 34% by weight, the viscosity of the slurry is excessively increased, which makes it difficult to control the thickness of the porous support. .

In addition, the distilled water is a solvent that serves to dissolve the metal oxide, ceramic or a combination thereof, it is preferably included in the slurry at 66 to 86% by weight. If the distilled water is less than 66% by weight, the viscosity of the slurry is high, so that the thickness of the porous support is unevenly formed. In addition, when the distilled water exceeds 86% by weight, the viscosity of the slurry is so thin that the slurry liquid discharged from the mold increases, so that the thickness of the formed porous support becomes too thin, thereby lowering the mechanical strength of the porous support.

The pore-forming agent is added to form pores in the support, to connect the pores to ensure breathability, for example, carbon, graphite, starch, resin, polymethyl methacrylate (PMMA), etc. Can be. As described above, the porosity is preferably higher than that of the porous layer located at the outermost portion of the porous support, so it is effective to add the pore forming agent differently accordingly.

First, the slurry for forming the porous layer located on the innermost side of the porous support preferably includes 1 to 10 parts by weight of the pore-forming agent based on 100 parts by weight of the total amount of at least one of the metal oxide, the ceramic, or a combination thereof. If the pore-forming agent is less than 1 part by weight, even if the porous layer is made thin, oxygen permeability is limited. If the pore-forming agent is more than 10 parts by weight, the innermost porous layer is coated with an oxygen separation membrane, making it difficult to form a film due to surface roughness. There is.

On the other hand, the slurry for forming a porous layer other than the porous layer located at the innermost portion of the porous support includes 15 to 40 parts by weight of the pore-forming agent based on 100 parts by weight of the total amount of at least one of the metal oxide, the ceramic, or a combination thereof. It is desirable to. If the pore-forming agent is less than 15 parts by weight, sufficient porosity is not formed in the porous support, and oxygen permeability is not good. If the pore-forming agent exceeds 40 parts by weight, the pores are excessively formed, resulting in a drop in mechanical strength of the support.

In addition, the dispersant is added to make the distribution of any one of the metal oxide, ceramic or combination thereof dissolved in the distilled water even. The dispersant may be an ethenyl benzene aqueous dispersant which is capable of dispersing other components without precipitating metal ions in the aqueous system as an aqueous dispersant. The dispersant is preferably added in an amount of 0.5 to 1.5 parts by weight based on 100 parts by weight of the total amount of at least one of the metal oxide, the ceramic, or a combination thereof. When the dispersant is less than 0.5 parts by weight, metal oxides and the like are not evenly dispersed in distilled water. When the dispersant is more than 1.5 parts by weight, the viscosity of the slurry is lowered.

On the other hand, the slurry preferably further comprises at least one of an antifoaming agent and a strength enhancer. The antifoaming agent is to prevent the generation of bubbles that may occur when the slurry is discharged, an oil blend containing a linear silicone oil such as dimethylpolysiloxane, methylphenylpolysiloxane, methylvinylpolysiloxane may be used. In addition, the strength enhancer to increase the strength of the porous support may include polyvinyl alcohol, polyethylene glycol or a mixture thereof.

In addition, the slurry preferably further includes a catalyst. The catalyst is for promoting oxygen permeation, and oxygen permeation membrane (membrane) material such as A _{1- x} Sr _x Co _{1 - y} Fe _y O _{3 -δ} and A is La and Ba may be widely used. In particular, a material which does not change phase under a low oxygen partial pressure of 20 atm or less is effective. Such a catalyst can contribute to the promotion of oxygen permeation by enlarging the surface area of the porous layer and preventing the phase change of the porous layer.

As a result, the slurry forming the porous layer located at the innermost part of the porous support is 14 to 34% of at least one of metal oxide, ceramic or combination thereof, 66 to 86% of distilled water, metal oxide, ceramic or Prepared by mixing 1 to 10 parts by weight of the pore-forming agent and 0.5 to 1.5 parts by weight of the dispersant based on 100 parts by weight of the total amount of at least one of the metal oxide, ceramic or a combination thereof based on 100 parts by weight of the total amount of at least one of the combinations thereof. do.

On the other hand, the slurry forming the porous layer other than the porous layer located at the innermost portion of the porous support is 14 to 34%, distilled water 66 to 86%, at least one of the metal oxide, ceramic or combination thereof, 15 to 40 parts by weight of pore formers and 100 to parts by weight of total amount of at least one of metal oxides, ceramics or combinations thereof, and 0.5 to 1.5 parts by weight of 100 parts by weight of the total amount of at least one of the oxides, ceramics or combinations thereof. It is prepared by mixing parts by weight.

In addition, the metal oxide, the ceramic or a combination thereof is more effective that the average particle diameter is 0.5 to 1.0㎛.

On the other hand, after the slurry is prepared as described above, the prepared first slurry is filled in the mold. The mold includes an inlet, an outlet and a valve. The inlet is where the slurry is introduced into the mold, and the outlet is where the slurry introduced into the mold is discharged out. In addition, the valve is to determine whether the discharge of the slurry, the discharge rate and the discharge, may be included in the discharge port may be formed separately from the discharge port may be formed in the mold.

On the other hand, by retaining the first slurry in the mold for a predetermined time to evenly adhere the slurry to the inner wall of the mold to a certain thickness, if it is fixed to the porous layer over time, this will form the appearance of the porous support. Therefore, the appearance of the porous support may vary depending on the shape of the mold.

Meanwhile, a first porous layer is obtained by discharging the remaining first slurry that is not fixed to the mold to mold the first porous layer fixed to the porous support, and bubbles may be generated during the discharge, so that the valve It is preferable to discharge slowly by adjusting. The discharged slurry can be recycled to prepare a porous support according to the present invention.

After the first porous layer is formed through the above-described first slurry manufacturing step, fixing step, and remaining first slurry discharge step, the second slurry manufacturing step, fixing step, and remaining second slurry discharge step are similarly repeated. 2 It forms a porous layer. Although only the second porous layer forming process is shown in FIG. 2, three or more porous layers may be formed by repeating the above process three or more times. That is, the present invention includes the step of preparing a porous support composed of at least two porous layers by repeating this process.

The number of the porous layers is not limited so long as it is two or more, and can be adjusted as necessary. If the porous support is made of only one porous layer having a high porosity, it may be advantageous in terms of securing oxygen permeability, but since the oxygen separation membrane is formed on the inner wall of the porous support, it is difficult to form the film due to the surface roughness if there are many pores. . Therefore, the two or more porous layers constitute a porous layer having a relatively high porosity at the outer periphery of the porous support, but a porous layer having a relatively low porosity at the innermost of the porous support coated with the oxygen separation membrane. To do this.

That is, the porosity of the porous layer located on the innermost side of the porous support is preferably lower than the porosity of other porous layers. In particular, the porosity of the other porous layer is more preferably 20 to 50 vol%, more preferably 2 to 18 vol%.

On the other hand, it is preferable that the slurry residence time in the mold during the manufacturing step of the porous support is 2 to 10 minutes . If the time is less than 2 minutes, the slurry is not formed on the inner wall of the molding die having a sufficient thickness may reduce the mechanical strength of the porous support. In addition, when the time exceeds 10 minutes, the amount of slurry fixed to the inner wall of the mold is excessively increased, the inner wall of the porous support becomes too thick, and thus the area in contact with the air supplied into the porous support is On the other hand, the efficiency of the oxygen passed through the oxygen separation membrane becomes longer because the time taken for the oxygen to pass through the pores in the porous support becomes longer.

In addition, in order to remove the water remaining in the porous support is subjected to a step of drying by passing heat or passing through hot air. The molded porous support is dried at room temperature for 24 to 48 hours, and then further dried at a temperature of 70 to 80 ° C for 12 to 24 hours.

In addition, the dried porous support is subjected to baking to increase the mechanical strength of the support and to form pores in the support. It is preferable to make the baking into 2 to 10 hours at the temperature of 1000-1300 degreeC. If the firing temperature is less than 1000 ℃ the strength is lowered, if the firing temperature exceeds 1300 ℃ densification of the support occurs, the porosity is lowered and is not economical. In addition, if the firing time is less than 2 hours, the support is not properly calcined and the mechanical strength is lowered. If the firing time exceeds 1300 ° C, particles such as metal oxides are excessively grown in the support, making it difficult to secure a uniform porosity. There is a problem.

On the other hand, the oxygen separation membrane coating is filled into the porous support prepared through the above-described process. Conventionally, the spray method was used as a method of coating the oxygen separation membrane on the support, but there was a problem that it is difficult to form a uniform oxygen separation membrane. Therefore, in the present invention, the coating liquid for forming the oxygen separation membrane is maintained in the support for a predetermined time so that the coating liquid is fixed to the inner wall of the support, and then the oxygen coating membrane is formed by discharging the remaining coating liquid. When forming the oxygen separation membrane in this manner, it is possible to form a dense uniform thin coating film on the inner wall of the support.

Coating the oxygen separation membrane on the prepared porous support will be described with reference to FIG. 3. 3 shows a process from (iii) to (iii), referring to FIG. 3, a method of manufacturing an oxygen separation tube in which an oxygen separation membrane is formed is (iii) prepared in the porous support 202. Filling the oxygen separation membrane coating liquid 201, (ii) the oxygen separation membrane coating liquid 201 is maintained in the porous support 202 for a predetermined time to the oxygen separation membrane 204 on the inner wall of the porous support 202 Forming (iii) discharging the remaining oxygen separation membrane coating liquid 201 from the porous support 202, (iii) drying the porous support 202 on which the oxygen separation membrane 204 is formed, (iii) ) Calcining the dried porous support 202.

The oxygen separation membrane coating solution includes 1 part by weight of the metal oxide and 10 to 30 parts by weight of the polar solvent consisting of Chemical Formula 3. The polar solvent may be, for example, water, alcohol, butanol, acetonitrile, acetone, acetylacetate, dichloromethane, chloroform, or a mixture thereof. When the polar solvent is included in the oxygen separation membrane coating liquid at less than 10 parts by weight, it is not easy to disperse the metal oxide, so that a uniform oxygen separation membrane cannot be formed. When the polar solvent exceeds 30 parts by weight, the viscosity of the oxygen separation membrane coating liquid is too thin. It is difficult to adhere to the inner wall of the porous support, making it difficult to form a dense oxygen separation membrane.

Then, the oxygen separator coating liquid is filled into the porous support. Since the porous support has a hollow shape through which the upper and lower sides pass, a stopper or a lid may be provided to allow the oxygen separation membrane coating liquid to stay and be discharged for a predetermined time. It may be sealed with tape instead of the plug. After the oxygen separation membrane coating solution is retained, the lid, stopper or tape may be removed when discharging the oxygen separation membrane coating solution.

When the oxygen separation membrane coating liquid is rapidly filled in the porous support, bubbles are generated, and thus the oxygen separation membrane may not be formed densely, and thus, the oxygen separation membrane coating liquid may be slowly filled.

After filling the porous support completely with the oxygen separation membrane coating solution, the oxygen separation membrane coating solution is held for a predetermined time so that the oxygen separation membrane coating solution is evenly fixed to the inner wall of the porous support.

The residence time is preferably 2 to 10 minutes. When the residence time is less than 2 minutes, the oxygen separation membrane coating liquid is insufficient to combine with the inner wall of the porous support, and thus the oxygen separation membrane coating liquid is not adhered to the inner wall of the porous support, thus insufficient oxygen separation membrane is formed in the air. Does not pass through as it is and does not separate into pure oxygen. In addition, if the residence time exceeds 10 minutes, the formed oxygen separation membrane is too thick, there is a problem that the oxygen transmittance falls.

When the oxygen separation membrane is fixed in an appropriate amount on the inner wall of the porous support to form an oxygen separation membrane, the remaining oxygen separation membrane coating liquid must be discharged from the porous support. Discharge of the residual oxygen separation membrane coating liquid may be discharged by transferring the residual oxygen separation membrane coating liquid to another container or removing the stopper from the porous support. The discharged coating composition coating liquid can be recycled to the coating method according to the present invention.

In addition, it is preferable to form two or more oxygen separation membrane layers by repeating the filling step, the residence step and the remaining coating liquid discharge step of the oxygen separation membrane coating solution two or more times. The effect when the oxygen separation membrane is formed of two or more layers is as described above in the oxygen separation tube.

On the other hand, the porous support is dried to remove moisture present in the oxygen separation membrane formed on the inner wall of the porous support, and to more completely adhere to the inner wall of the porous support. In the drying, the porous support on which the oxygen separation membrane is formed is dried at room temperature for 12 to 24 hours, and then further dried at 70 to 80 ° C. for 6 to 12 hours.

If the drying time at room temperature is less than 12 hours, the drying time is insufficient to dry the oxygen separation membrane, and if the drying time exceeds 24 hours, the oxygen separation membrane may be dropped from the porous support. After the first drying, the second drying is carried out for 6 to 12 hours at 70 to 80 ℃, if the secondary drying temperature is less than 70 ℃ temperature is too low drying is insufficient, if it exceeds 80 ℃ excessive drying occurs Cracks may occur in the oxygen separation membrane. In addition, if the secondary drying time is less than 6 hours, the drying time is less than perfect, and if it exceeds 12 hours, cracks may occur due to excessive drying.

In particular, the drying is divided into primary and secondary as described above, when the drying time and drying temperature are rapidly increased during drying of the porous support on which the oxygen separation membrane is formed, the oxygen separation membrane may be separated without being fixed to the inner wall of the porous support. This is to prevent the cracks may occur in the separator.

The porous support dried as described above is fired to sufficiently increase the strength and to prevent the inner wall of the porous support from melting due to the oxygen separator coating liquid. The porous support on which the oxygen separation membrane is formed has a firing time of 12 to 24 hours and a firing temperature of 1000 to 1500 ° C.

If the firing temperature is less than 1000 ° C., the oxygen separation membrane is not formed densely on the inner wall of the porous support. If the firing temperature is higher than 1500 ° C., the metal oxide, etc., in the oxygen separation membrane coating solution is volatilized, and thus a dense oxygen separation membrane is not formed. In addition, when the firing time is less than 12 hours, the time is short, and the effect of firing is insufficient, and when the firing time exceeds 24 hours, the oxygen separation membrane may be dropped.

The above-described oxygen separation tube of the present invention and a method of manufacturing the same may include a porous support composed of at least two porous layers having different porosities, thereby preventing surface roughness, which may be advantageous for forming an oxygen separation membrane, and may be formed on the inner wall of the porous support. By including the formed oxygen separation membrane to prevent damage to the oxygen separation membrane during combustion or during the chemical process it is possible to increase the oxygen permeability. That is, the present invention is to ensure the excellent oxygen permeability and ease of forming the oxygen separation membrane at the same time.

On the other hand, the oxygen separation tube of the present invention prepared according to the above can be used in boilers, chemical industry, synthesis gas, a process of partially oxidizing methane. When the oxygen separation tube of the present invention is applied to a boiler, by installing the oxygen separation tube in the combustion chamber, pure oxygen can be supplied to the combustion process, thereby improving combustion efficiency, and the oxygen separation tube is required. You can use several together.

In addition, although the tube of the present invention has been described as being limited to oxygen separation, it may be used for separation of other gases, for example, for hydrogen separation.

Hereinafter, the present invention will be described more fully through specific examples.

(Example)

To summarize briefly the following experimental procedure, (a) an oxygen separation tube coated with an oxygen separation membrane on a porous support composed of one porous layer having a relatively high porosity, and (b) one porous layer having a relatively low porosity. Oxygen separation tube coated with oxygen separation membrane on the porous support, (c) Oxygen separation membrane is coated on the porous support consisting of a total of two porous layers in which a porous layer having a relatively low porosity is further formed on the porous layer having a relatively high porosity. Electron microscopy (SEM) photographs of the oxygen separation tube coated with two layers of the oxygen separation membrane on the porous support such as the oxygen separation tube and (d) (c) were analyzed. (a) and (b) are comparative examples, and (c) and (d) correspond to invention examples.

(a) Tube manufacturing process

First, alumina powder (Al ₂ O ₃ , 76% by weight), distilled water (24% by weight) and dispersant Cera4sperse (0.9 parts by weight based on 100 parts by weight of the total amount of alumina and distilled water) having an average particle size of about 0.54 µm were prepared. Each was weighed and prepared. The slurry was prepared by milling for 2 periods to ensure sufficient mixing. In addition, a polyether type SN-Defoamer 485 (0.02 parts by weight based on 100 parts by weight of total amount of alumina and distilled water) as an antifoaming agent, and 0.8 parts by weight of 100 parts by weight of polyvinyl alcohol (PVA, alumina and distilled water as a strength enhancer). Parts by weight) and polyethylene glycol (PEG 400, 0.125 parts by weight based on 100 parts by weight of alumina and distilled water) and PMMA S 400 (30 parts by weight based on 100 parts by weight of total amount of alumina and distilled water) as pore-forming agents The slurry was prepared by milling for 2 hours to mix sufficiently.

The slurry was filled and filled in a mold formed of a porous gypsum mold having an appearance of 25 cm 2, 30 cm 2, and 40 cm 2 in height over 30 to 60 seconds. The mold is capable of forming a mold having a diameter of 4 cm and a height of 40 cm therein. Thereafter, the packed slurry was held for 3-4 minutes, and the remaining unsettled slurry was discharged from the mold over 30 to 60 seconds to form a porous layer.

Thereafter, the formed porous support was dried in a mold for 48 hours. From the mold, the porous support was dried in an oven at about 70 ° C. for about 24 hours. The dried porous support was calcined by holding at an electric furnace for 5 hours at 1200 ° C. to complete the porous support.

Then, BaCo _0.7 Fe _0.22 Nb _0.08 O _{3 + δ} powder was mixed with a methyl cellulose solution (0.67% sol) to form an oxygen separator on the inner wall of the porous support to prepare an oxygen separator coating solution. The mixed mass ratio of the metal oxide powder and the methyl cellulose solution was 1: 4. That is, 25 g of the metal oxide was mixed with 100 g of a methyl cellulose solution to complete an oxygen separator coating solution.

Then, one end of the porous support was blocked with a tape, and the oxygen separator coating liquid was filled to the upper end of the support for 30 to 60 seconds. Thereafter, the oxygen separation membrane coating solution was kept in the porous support for about 4 minutes, and then the remaining oxygen separation membrane coating liquid which was not fixed was discharged and removed. Then, an oxygen separation tube coated with an oxygen separation membrane on the inner wall of the porous support was naturally dried at room temperature for 6 hours, and then dried in an oven at 80 ° C. for 12 hours.

This was taken with an electron microscope photograph and is shown in (a).

(b) tube manufacturing process

After the preparation process as described above (a), the oxygen separation tube containing a pore-forming agent added to 5 parts by weight based on 100 parts by weight of the total amount of alumina and distilled water was prepared.

This was taken with an electron microscope photograph and is shown in (b).

(c) tube manufacturing process

After the first porous layer was formed using the first slurry prepared in the same ratio as (a), and after 2 to 5 minutes, the first porous layer was formed from the second slurry prepared in the same ratio as (b). The mold was filled into a mold to form a second porous layer. Subsequent manufacturing processes were carried out as above to prepare a tube for oxygen separation.

This was taken with an electron microscope photograph and is shown in (c).

(d) Tube manufacturing process

As in (c), a porous support composed of the first and second porous layers was prepared. Thereafter, the oxygen coating solution was filled and retained in the support, and the remaining coating solution was discharged to form the first oxygen separation membrane. After 1 hour, the same process was repeated to form the second oxygen separation membrane. Subsequent manufacturing processes were carried out as above to prepare an oxygen separation tube.

This was taken with an electron microscope photograph and shown in (d).

Result Analysis

First, looking at the (a) picture, it can be seen that the formation force of the oxygen separation membrane is not very good, the density is very poor, and the uniformity of the membrane is also not very good. This means that the pore-forming agent added to the support has a relatively high porosity, which has a very detrimental effect on film formation. Therefore, it can be seen that the oxygen separation tube having the oxygen separation membrane formed on the support having such a high porosity has poor oxygen separation performance.

And, looking at the (b) picture, it can be seen that the oxygen separation membrane is very dense and uniformly formed well. This means that since the pore-forming agent is relatively small and the porosity is low, film formation was easy. However, there is a problem in that the entire support has a low porosity and poor oxygen permeability.

However, in the (c) picture, it can be seen that the second porous layer coated with the oxygen separation membrane has a very dense and uniform oxygen separation membrane as in (b) because the ratio of the pore-forming agent is low as in (b). have. At the same time, sufficient pore-forming agent is included in the first porous layer, so that the air permeability of the entire porous support can be kept excellent, thereby ensuring excellent membrane formation ease and oxygen permeability.

In addition, in the (d) picture, the oxygen separation membrane is formed on the same layer as (c), and the additionally formed second oxygen separation membrane has a somewhat uneven surface with the first oxygen separation membrane. As a result, the reactivity with oxygen in the air is increased, so that the oxygen separation performance can be more excellently secured.

101: first slurry
102: forming mold
103: first porous layer
104: second slurry
105: second porous layer
106, 202: porous support
201: oxygen separator coating liquid
203: stopper
204: oxygen separation membrane

Claims (24)

A porous support composed of two or more porous layers having different porosities; And
The oxygen separation tube coated on the inner wall of the porous support, to separate the oxygen in the air passing through the interior of the porous support, comprising an oxygen separation membrane comprising a metal oxide of the formula (3).
(3)
BaCo _1-XY A _X B _Y O _{3 + δ}
Wherein A and B are at least one metal selected from the group consisting of transition metals, and the sum of X and Y is 0 ≦ X + Y ≦ 1, and the value of δ is 2.7 to 3.3. The method of claim 1,
The porous layer is oxygen separation tube, characterized in that it comprises at least one of a metal oxide, a ceramic or a combination thereof. The method of claim 1,
An oxygen separation tube, characterized in that the porosity of the porous layer located on the innermost side of the porous support is lower than that of other porous layers. The method of claim 3,
The porosity of the porous layer located in the innermost is 2 to 18 vol%, the porosity of the other porous layer is 20 to 50 vol%, the tube for oxygen separation. The method of claim 2,
The metal oxide, ceramic or a combination thereof is an oxygen separation tube, characterized in that the average particle diameter of 0.5 to 1㎛. delete Preparing a porous support composed of two or more porous layers having different porosities;
Filling an oxygen separation membrane coating solution into the porous support;
Forming an oxygen separation membrane on the inner wall of the porous support by remaining the oxygen separation membrane coating solution in the porous support for a predetermined time;
Discharging the remaining oxygen separation membrane coating solution from the porous support;
Drying the porous support on which the oxygen separation membrane is formed; And
Method for producing an oxygen separation tube comprising the step of firing the porous support on which the dried oxygen separation membrane is formed. The method of claim 7, wherein
Preparing the porous support,
Preparing a first slurry by mixing at least one of a metal oxide, a ceramic, or a combination thereof, distilled water, a pore former, and a dispersant;
Filling the first slurry in a mold and staying for a predetermined time to fix the first slurry on an inner wall of the mold;
Discharging the remaining first slurry that is not fixed from the mold to form a first porous layer;
Mixing at least one of a metal oxide, a ceramic, or a combination thereof, distilled water, a pore former, and a dispersant to prepare a second slurry having a different addition ratio of the first slurry and the pore former;
Filling the second slurry in a molding mold to which the first porous layer is fixed and retaining for a predetermined time to fix the second slurry on the inner wall of the first porous layer;
Discharging the second slurry not adhered from the first porous layer to form a porous support including an outer first porous layer and an inner second porous layer;
Drying the molded porous support; And
Method for producing an oxygen separation tube comprising the step of firing the dried porous support. The method of claim 8,
Repeating the slurry manufacturing step, the fixing step and the remaining slurry discharge step three or more times to prepare a porous support consisting of three or more porous layers having different porosity, characterized in that it comprises a step of producing a tube for oxygen separation. . The method of claim 8,
And a porosity of the porous layer located at the innermost part of the porous support is lower than that of other porous layers. The method of claim 10,
The porosity of the porous layer located in the innermost is 2 to 18 vol%, the porosity of the other porous layer is characterized in that 20 to 50 vol% oxygen separation tube manufacturing method. The method of claim 10,
The slurry forming the porous layer located at the innermost part of the porous support is in weight percent, at least one of metal oxides, ceramics or combinations thereof is 14 to 34%, distilled water is 66 to 86%, metal oxides, ceramics Or 1 to 10 parts by weight of the pore-forming agent and 100 to 5 parts by weight of the dispersant based on 100 parts by weight of the total amount of the metal oxide, the ceramic or the combination thereof. Oxygen separation tube manufacturing method characterized in that. The method of claim 10,
The slurry for forming a porous layer other than the porous layer located at the innermost portion of the porous support may include 14 to 34% by weight of metal oxide, ceramic or a combination thereof, 66 to 86% by weight of distilled water, and 15 to 40 parts by weight of the pore former and 100 to parts by weight of the total amount of at least one of the metal oxides, ceramics or combinations thereof, and 0.5 to 1.5 parts by weight of the total amount of at least one of the oxides, ceramics or combinations thereof. Oxygen separation tube manufacturing method comprising a weight part. The method according to claim 12 or 13,
Said slurry further comprises at least one of an antifoaming agent and a strength enhancer. The method according to claim 12 or 13,
The slurry is an oxygen separation tube manufacturing method characterized in that it further comprises a catalyst. The method according to claim 12 or 13,
The metal oxide, ceramic or a combination thereof is an oxygen separation tube manufacturing method, characterized in that the average particle diameter of 0.5 to 1㎛. The method according to claim 8 or 9,
The forming mold has an inlet for injecting a slurry, an outlet for discharging the slurry and a valve for adjusting the discharge rate of the slurry characterized in that it comprises a valve. The method according to claim 8 or 9,
Retention time of the slurry is 2 to 10 minutes, characterized in that the oxygen separation tube manufacturing method. The method according to claim 8 or 9,
The molded porous support is dried at room temperature for 24 to 48 hours and then further dried for 70 to 80 hours at 12 to 24 hours at 70 to 80 ℃ oxygen separation tube manufacturing method. The method of claim 7, wherein
The oxygen separation membrane coating solution is 10 to 30% by weight of at least one polar solvent selected from the group consisting of water, alcohol, butanol, acetonitrile, acetone, acetylacetate, dichloromethane, chloroform and the like 1 parts by weight of the metal oxide consisting of the formula Oxygen separation tube manufacturing method comprising a portion.
(3)
BaCo _{1 -X- Y} A _X B _Y O _{3 + δ}
Wherein A and B are at least one metal selected from the group consisting of transition metals, and the sum of X and Y is 0 ≦ X + Y ≦ 1, and the value of δ is 2.7 to 3.3. The method of claim 7, wherein
Retaining the oxygen separation membrane coating solution for a predetermined time in the porous support is a method for producing an oxygen separation tube, characterized in that made for 2 to 10 minutes. The method of claim 7, wherein
Method for producing an oxygen separation tube, characterized in that to form two or more oxygen separation membrane layer by repeating the oxygen coating liquid filling step, the retention step and the remaining coating liquid discharge step two or more times. The method of claim 7, wherein
Drying the porous support on which the oxygen separation membrane is formed is dried for 12 to 24 hours at room temperature and then further dried for 6 to 12 hours at 70 to 80 ℃ oxygen separation tube manufacturing method. The method of claim 7, wherein
The firing of the porous support on which the dried oxygen separation membrane is formed is a method for producing an oxygen separation tube, characterized in that for 12 to 24 hours at 1000 to 1500 ℃.

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