JPH0824667A - Carrier and filter using the same - Google Patents

Abstract

PURPOSE:To obtain a carrier which can utilize more efficiently an active component such as a catalyst by forming the carrier from a three dimensional porous metal body of A1 or A1-alloy having specified communicating pores, and making the surface of the carrier have a finely uneven oxidized film formed by alumite treatment. CONSTITUTION:The carrier for an active component is formed from a three dimensional porous metal body of A1 or A1-alloy having communicating pores and porosity of 80% or more, and the surface has a finely uneven oxidized film. The oxidized film has a large number of pores several hundreds Angstrom in diameter so that the specific surface area is large and further increased by the unevenness on the surface the pores. In this way, the contact area with gas increases for reactions or separation, contributing largely to the improvement of decomposition and recovery efficiency. The oxidized film is also effective to protect the porous metal body from corrosion due to corrosive gas contained slightly in exhaust gas.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a carrier for supporting an active component such as a catalyst, and particularly to an air pollutant contained in exhaust gas from a factory, a power plant, or an automobile, which has been a problem in recent years, or global warming. The present invention relates to a filter carrier for preventing the emission of carbon dioxide gas, which is the cause, to the atmosphere, and a filter using the same.

[0002]

2. Description of the Related Art Carbon dioxide emitted from a fixed source that emits a large amount of carbon dioxide, such as a power plant or a factory, has a relatively high concentration and is considered to be easily recovered. ing. As a technology for recycling carbon dioxide gas, for example, as disclosed in JP-A-5-337334,
For example, carbon dioxide is fixed in a number of chemical products such as amine-based absorbents. As a method for adsorbing / desorbing carbon dioxide, a solid adsorbent such as activated carbon is used to adsorb carbon dioxide under pressure and then desorb it under reduced pressure to remove carbon dioxide from a large amount of exhaust gas. There is also a method of efficiently separating carbon dioxide gas. Further, a method of decomposing carbon dioxide gas with a decomposed material in which an iron oxide catalyst is supported on plate-like alumina (JP-A-4-135621), and carbon dioxide gas is reduced by a molybdenum sulfide catalyst supported on alumina, titania or the like. Method (JP-A-4-363142)
No.) is also proposed.

[0003]

However, although the method utilizing the adsorption / desorption of carbon dioxide gas can regenerate the adsorbent, it requires a huge amount of treatment equipment such as a gas treatment tower, and a large amount of exhaust gas is discharged. It is not suitable or economical to process gas in real time. Further, in the method utilizing the above-mentioned decomposition catalyst, equipment such as a gas treatment tower is not necessary, but the catalyst carrier such as alumina used is in the form of a thin plate or simply fine powder in order to efficiently utilize the catalyst components. It is still insufficient. The present invention aims to provide a carrier for more efficiently utilizing an active component such as a catalyst under such a situation, and particularly to a carrier such as pollutants in exhaust gas or carbon dioxide gas. A filter carrier for efficiently removing substances that are not desirable to be released and a filter using the same, especially suitable for efficiently and economically separating and recovering a large amount of gas such as carbon dioxide gas from a fixed source Another object of the present invention is to provide a simple filter carrier and a filter using the same.

[0004]

As a result of intensive studies, the present inventors have found that it is effective to use a porous body of Al or Al alloy having a specific structure as a carrier, and have arrived at the present invention. . That is, the present invention comprises (1) a three-dimensional metal porous body made of Al or an Al alloy having continuous pores having a porosity of 80% or more, and having an oxide film whose surface has fine surface irregularities by alumite treatment. The gist of the present invention is a carrier for active ingredients, (2) a filter carrying a component capable of adsorbing, absorbing or decomposing a specific component on the surface of an oxide film of the carrier described in (1) above. As described above, in the carrier of the present invention, a porous metal body made of Al or an Al alloy and having communicating pores having a porosity of 80% or more is used. Where Al or A
The reason why the l-alloy is used as a material is that, in addition to contributing to weight reduction of filters and the like, an oxide film having fine pores can be easily formed by alumite treatment as described below.

Examples of the Al alloy used in the present invention include Al / S; Al / Mg; Al / Cu; Al / Ni. Moreover, in order to apply it as a filter, it is necessary to reduce the ventilation resistance of the fluid to be treated, so 80%
A porous body structure having communication holes having the above porosity is used. The metal porous body made of such Al or Al alloy used in the present invention can be manufactured by a known method. For example, the method described in JP-B-38-17554 can be used. According to this method, for example, by spraying a paint, etc., on a polyurethane foam having a foamed structure, Al powder, phenol resin as a binder, alcohol as a diluent, and carboxymethyl cellulose as an additive at 40, 10, 48 and 2% by weight, respectively, are sprayed. Apply to. Apply this coating at room temperature for 1
Dry for 0 minutes and 120 ° C. for 10 minutes, and then bake at 380 ° C. for 50 minutes. Then, in a hydrogen stream at 630 ° C, 2
By firing for a time, an Al porous body is formed.

Next, an oxide film is formed on the porous metal body made of Al or Al alloy by alumite treatment. This oxide film has large surface irregularities due to the presence of many hundreds of Å micropores. Therefore, in addition to having a large specific surface area because it is a porous structure by nature, its specific surface area is further increased, and the contact area with the gas for the purpose of reaction, separation, or recovery is increased, and the decomposition recovery efficiency is improved. Greatly contribute to. Further, this oxide film also functions to prevent the corrosion of the porous metal by the corrosive gas contained in the exhaust gas in a trace amount. The alumite treatment itself for forming the oxide film can be performed by a known method. For example, it can be performed by a method using a general sulfuric acid electrolyte. Also, as the thickness of the oxide film,
The thickness is preferably 0.1 μm or more and 10 μm or less. 0.1
This is because when the thickness is less than 10 μm, the surface irregularities are small, and in addition, there is a problem in corrosion resistance, and when the thickness exceeds 10 μm, the workability such as bending and bending of the porous metal body deteriorates, and the filter shape is restricted.

As is clear from what has been described so far, the carrier of the present invention has a small air flow resistance, a remarkably large specific surface area, is lightweight, and is excellent in molding processability. It is useful as a carrier, and is also suitable as a carrier for a filter for separating and removing a specific component in a fluid. For example, it is useful as a filter for automobile exhaust gas, or removal of harmful components such as SO _x and NO _x from exhaust gas of thermal power plants and factories. However, the carrier of the present invention is particularly suitable for a filter capable of efficiently separating or decomposing carbon dioxide gas from exhaust gas by supporting a material capable of adsorbing / absorbing or decomposing carbon dioxide gas on its skeleton surface. Here, as the substance that adsorbs or decomposes carbon dioxide, for example, it is also possible to adsorb carbon dioxide with a Group IIa metal or its oxide. Further, oxygen-defective magnetite as described in JP-A-4-135621 and JP-A-4-36
Catalytic materials such as molybdenum sulfide described in 3142 may be used.

Further, as a method for supporting these substances on the skeleton surface of the metal porous body, a method of spraying and applying fine powder together with a binder, a film formation by a sol-gel method or a plating method, vacuum deposition, sputtering, ion plating, etc. Coating, CVD, plasma CVD
It is also possible to use a film forming method by a vapor phase method such as a method. In the filter structure using the porous metal body of the present invention, it is possible to easily and inexpensively realize a filter structure having a desired shape in accordance with a discharge facility such as carbon dioxide gas, since machining such as cutting and bending is easy. is there. Furthermore, the filter after adsorbing, absorbing or decomposing carbon dioxide, etc. can be easily regenerated by heat treatment or heat treatment in a reducing gas such as hydrogen. High concentration carbon dioxide gas re-released during these regeneration processes. It is also possible to reuse hydrocarbon gas and hydrocarbon gas.

[0009]

【Example】

Example 1 In a polyurethane foam having a thickness of 2 mm, 50 parts by weight of an Al alloy (Mg 1 wt%) powder having an average particle size of 8 μm, 10 parts by weight of an acrylic resin as a binder resin, and 38 parts by weight of benzyl alcohol as a diluent, A slurry liquid prepared by mixing 2 parts by weight of carboxymethyl cellulose as a dispersant was applied, dried at room temperature, and then 620 in a reducing atmosphere.
The Al alloy porous body (porosity 91%) formed by heat treatment at ℃ was anodized under the following conditions. Electrolyte solution 10% sulfuric acid solution temperature 2 ° C. current density 1 A / dm ² hours 20 minutes At this time, the thickness of the oxide film was about 6 μm.

A fine powder of calcium oxide was sprayed on the Al porous body having the oxide film at a rate of 50 g / cm ^{2 by using} an acrylic resin as a binder to apply the powder, followed by degassing and drying. The thus-obtained porous body was cut into a width of 1 m and a length of 15 m, which was wound into a cylindrical shape as shown in FIG. 1 and placed in an anodized aluminum cylinder having a finished diameter of 20 cm. The gap between the center and the outer cylinder was filled with an alumite-treated aluminum plate. An adsorption experiment was conducted using the finished filter. The outline of the apparatus used for the experiment is shown in FIG. Air containing processing gas 10% CO ₂ is flowed at a flow rate of 1 liter / min, the gas after the filter is sampled, and a commercially available CO ₂ concentration detection tube (2% concentration or more is detected)
Was used to confirm the presence of CO ₂ . Approximately 21 hours after the start of air flow, CO ₂ started to be detected. After the experiment was completed, the filter was heated at 500 ° C. under vacuum to remove CO ₂
Was recovered and regenerated. When the regenerated filter was subjected to the experiment again, almost the same result as the initial result was obtained.

Comparative Example The characteristics of the Al porous body not subjected to the alumite treatment in Example 1 as a filter were evaluated in the same manner.
CO ₂ started to be detected 2 hours after starting the flow of ir.

[0012]

As described above, the carrier for active ingredient of the present invention has a remarkably increased specific surface area as compared with the conventional carrier, so that the loaded active ingredient can be efficiently utilized. Further, a filter using this can efficiently and economically separate and recover carbon dioxide gas or remove pollutants without installing large-scale equipment.

[Brief description of drawings]

FIG. 1 is an explanatory view of a filter in which a carrier for an active ingredient comprising an Al or Al alloy porous body of the present invention is wound in a cylindrical shape,

FIG. 2 is a schematic diagram of an experimental apparatus used in Examples.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location B01J 37/02 ZAB 301 K

Claims (4)

[Claims] 1. Al having communication holes with a porosity of 80% or more
Or, it consists of a metal three-dimensional porous body made of Al alloy,
A carrier for an active ingredient, characterized in that its surface has an oxide film having fine surface irregularities by anodizing. 2. The thickness of the oxide film is 0.1 μm or more and 10 μm.
The carrier for an active ingredient according to claim 1, which is less than or equal to m. 3. A filter, wherein the oxide film surface of the carrier according to claim 1 carries a component capable of adsorbing, absorbing or decomposing a specific component. 4. The oxide film has a thickness of 0.1 μm or more and 10 μm.
The filter according to claim 3, wherein the filter is m or less.