JP3881060B2 - Method for producing honeycomb solid catalyst - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a manufacturing method of a honeycomb JoNaru form of inorganic fibers coated with a solid catalyst. More specifically, the present invention provides a method for producing a honeycomb-shaped solid catalyst having high reactivity and relatively light weight by laminating and arranging inorganic fibers subjected to shaping treatment before drying and firing in multiple stages. .
[0002]
[Prior art]
As a conventional honeycomb-shaped solid catalyst, a ceramic honeycomb obtained by kneading and firing a solid catalyst is known. Further, as disclosed in Japanese Patent Laid-Open No. 55-159842, there is known a method in which a nonwoven fabric of inorganic fibers or the like is previously formed into a wave shape and then laminated to form a honeycomb.
[0003]
[Problems to be solved by the invention]
However, among the above methods, the sintered ceramic honeycomb has problems such as cracking and chipping. In addition, there is a disadvantage that the weight is relatively large for maintaining the shape. Further, the method of laminating a nonwoven fabric of inorganic fibers or the like in advance after corrugation has a drawback that the dimensions of the honeycomb are limited by the size of the corrugating machine.
The object of the present invention is to eliminate these drawbacks of the prior art and to provide a method for producing a honeycomb-shaped solid catalyst having a high reaction activity and a relatively light weight.
[0004]
[Means for Solving the Problems]
As a result of diligent research to solve the above-mentioned drawbacks, the inventors have made an inorganic fiber body mainly composed of an oxide into a compatible solvent with an oxide precursor that becomes an oxide by heating and an organic resin. After being immersed in the dissolved solution, it is arranged into a desired cylinder shape, and a relatively lightweight honeycomb solid catalyst can be formed by arranging multiple layers at any time before drying, after drying, or before firing. As a result, the present invention has been completed.
That is, the method for producing a honeycomb-shaped solid catalyst according to claim 1 is an oxidation that is a catalyst represented by BOy by heating a substrate made of an inorganic fiber body mainly composed of an oxide represented by a composition formula AOx. After immersing in a solution obtained by dissolving an oxide precursor and an organic resin in a compatible solvent, drying and firing, the oxide is bonded to the substrate by AOB bond. A method for producing a honeycomb-shaped solid catalyst to be coated, in which inorganic fiber bodies are arranged in a desired cylindrical shape and dried and then laminated and fired in multiple stages, or arranged in a desired cylindrical shape and arranged in multiple stages. It is characterized by being dried and fired later.
Further, in the method for producing a honeycomb-shaped solid catalyst according to claim 2 , the residual organic matter is removed and the catalytic characteristics of the coated oxide are exhibited by setting the temperature at the time of firing in the range of 200 to 600 ° C. It is characterized by that.
The method for producing a honeycomb-shaped solid catalyst according to claim 3 , wherein the organic resin is a resin having a decomposition temperature not lower than 200 ° C. and not higher than the firing temperature, thereby reducing the falling off of the coated oxide. It is characterized by.
The honeycomb-shaped solid catalyst according to claim 4 is characterized in that the substrate is made of an inorganic fiber cloth to further reduce the weight and to increase the amount of oxide to be covered.
The method for producing a honeycomb-shaped solid catalyst according to claim 5 is characterized in that the substrate is an inorganic fiber sleeve mainly composed of silicon oxide to form a strong bond with the oxide thin film.
[0005]
DETAILED DESCRIPTION OF THE INVENTION
Examples of the inorganic fiber body mainly composed of the oxide include woven fabric, nonwoven fabric, and paper. Among these, a woven fabric having a basis weight of 10 to 900 g / m ² is preferable from the viewpoint of strength. In order to achieve a cylindrical shape, it is preferable to use a fiber product knitted in a tubular shape, that is, an inorganic fiber sleeve.
The inner diameter (mm) and the unit weight (g / m) of the inorganic fiber body may be any amount, but 1 to 100 mm, 1 to 300 g / m, especially 15 in terms of handling properties and oxide loading. -50 mm and 25-130 g / m are preferred.
[0006]
Moreover, the material of the inorganic fiber which comprises a fiber body should just have oxides, such as A = Si, Al, Ti, Zr, as main components, such as glass and a ceramic. Among these, inorganic fibers mainly composed of silicon oxide that can form a strong bond with the oxide thin film are preferable. Examples of the inorganic fiber containing silicon oxide include fibers made of quartz glass, high quartz glass, E glass, C glass, S glass, A glass, etc., but E glass fiber is preferable from the viewpoint of economy. .
The average fiber diameter of the inorganic fiber is not particularly limited, but is preferably 0.1 to 20 microns because it can be manufactured and easily processed into a fiber body.
[0007]
In addition, metal alkoxides, metal chlorides, metal sulfides, metal acetates, and the like can be used as precursors that become metal oxides upon heating, but alcohols are compatible solvents because of their compatibility with organic resins. In the case of using a metal alkoxide, and in the case of using water as a compatible solvent, it is preferable to select a metal chloride. However, when the precursor and the organic resin are compatible, any combination may be selected.
[0008]
As the organic resin, acrylic resin, olefin resin, etc. are generally used. However, since it is necessary to oxidatively decompose in the baking process in the manufacturing process, a resin having a decomposition temperature of 200 ° C. or higher and a baking temperature or lower It is only required to be compatible with the metal oxide precursor, and is not particularly limited by the type and molecular weight of the monomer.
[0009]
The inorganic fiber body is immersed in the solution of the organic resin and metal oxide precursor selected in this manner, and is then dried, and then dried. At this time, in order to arrange it into a cylindrical shape, it is preferable to mold using a mold such as metal, ceramic, plastic, and wood. Furthermore, the mold used for molding is made into a cylindrical body such as a cylinder, a square cylinder or a deformed cylinder according to the desired shape, and an inorganic fiber body immersed in a solution of an organic resin and an oxide precursor is placed on the outer wall of this mold. It is good to shape | mold or make it closely_contact | adhere to an inner wall.
[0010]
The step of stacking the layers in multiple stages can be performed before drying, after drying, or before firing . However, if it is not desired to use a binder or the like that is unnecessary for the catalytic function, it is preferable to stack the layers before drying and bond the cylindrical bodies together by sintering the oxide thin film.
[0011]
Although drying temperature changes with boiling points of a compatible solvent, it is preferable to carry out in 40-150 degreeC. Next, the organic residue constituting the precursor of the organic resin or metal oxide is removed by baking the dry film. By this firing, the metal oxide precursor is changed to a metal oxide, and the organic resin is oxidatively decomposed to obtain a thin film having an A—O—B bond. In addition, the shape can be maintained by the sintering action of the thin film.
[0012]
【Example】
Next, description more specific examples.
The inorganic fiber body, the precursor material of the oxide catalyst, the organic resin, and the like have the same effect as long as the above conditions are satisfied. Therefore, as a representative, E glass fiber sleeve (main component SiO ₂ ) as an inorganic fiber body, titanium isopropoxide as an oxide precursor, acrylic resin (decomposition temperature 350 ° C.) as an organic resin, and ethyl alcohol as a compatibilizer. Select and explain a combination.
[0013]
Example 1
An E glass fiber sleeve having an inner diameter of 10 mmφ was immersed in a solution in which 10 g of titanium isopropoxide as an oxide precursor and 10 g of an acrylic resin were dissolved in 180 g of ethyl alcohol. The sleeve was taken out from the solution and placed in multiple stages in a state of being covered with a ceramic hexagonal cylinder of 5 mmφ, dried and cured at 60 ° C. for 1 hour, then heated to 450 ° C. at a rate of 1 ° C. per minute, By holding at 450 ° C. for 5 hours, the organic resin is completely oxidatively decomposed, and at the same time, titanium isopropoxide is changed to TiO ₂ oxide, a TiO ₂ film is formed on the fiber, and the ceramic hexagonal cylinder is pulled out to form a honeycomb. A solid catalyst was prepared.
[0014]
The shape retention at this time was good. Further, when the thickness of the TiO ₂ film was confirmed by SEM, it was about 0.3 μm and adhered firmly. Furthermore, when this film was analyzed by EPMA and ESCA, the presence of Si—O—Ti bonds was confirmed.
[0015]
This honeycomb-shaped solid catalyst is placed in a reaction vessel having a size of 200 mm × 200 mm × length 500 mm, air at 350 ° C. containing 100 ppm of NO _x is passed at a rate of 1 liter / min, and ammonia with respect to the amount of inlet NO _x And the decomposition efficiency was measured. As a result, the No _x concentration was 10 ppm or less at the outlet, and it was confirmed that the reaction by the catalyst was proceeding efficiently.
Here, FIG. 1 is an external view of a honeycomb-shaped solid catalyst 1 manufactured according to this embodiment. FIG. 2 is a model diagram when the honeycomb solid catalyst 1 is arranged in the reaction vessel 2. In the figure, 3 indicates a flow path of the reactant.
[0016]
【The invention's effect】
As described above, the honeycomb solid catalyst according to the present invention is excellent in shape retention by forming a thin film having a layer having an A-O-B bond on a fiber, and is a relatively lightweight catalyst molded body. Can be provided.
[Brief description of the drawings]
FIG. 1 shows an example of a honeycomb solid catalyst of the present invention.
FIG. 2 shows an example of a method for using the honeycomb solid catalyst of the present invention, and is a model diagram when the honeycomb solid catalyst is arranged in a reaction vessel.
[Explanation of symbols]
1 Honeycomb Solid Catalyst 2 Reaction Tank 3 Reactant Flow Path

Claims (5)

  A base material composed of an inorganic fiber body mainly composed of an oxide represented by the composition formula AOx is compatible with an oxide precursor and an organic resin that becomes an oxide that is a catalyst represented by BOy by heating. A method for producing a honeycomb-shaped solid catalyst in which the base material is coated with an AOB bond by dipping in a solution dissolved in a solvent, followed by drying and firing, and an inorganic fiber body A honeycomb-shaped solid catalyst prepared by drying in a desired cylindrical shape and then stacking and firing in multiple stages, or drying and firing after arranging in a desired cylindrical shape and stacking in multiple stages Method. The method for producing a honeycomb-shaped solid catalyst according to claim 1, wherein the firing temperature is in a range of 200 to 600 ° C. The method for producing a honeycomb-shaped solid catalyst according to any one of claims 1 and 2 , wherein the organic resin is a resin having a decomposition temperature of 200 ° C or higher and lower than the firing temperature. The method for producing a honeycomb-shaped solid catalyst according to any one of claims 1 to 3 , wherein the base material is an inorganic fiber woven fabric. The method for producing a honeycomb-shaped solid catalyst according to claim 4, wherein the substrate is an inorganic fiber sleeve mainly composed of silicon oxide.

Images