JPH064136B2 - Method for producing porous iron catalyst support - Google Patents

Description

TECHNICAL FIELD The present invention relates to a catalyst carrier used for producing a catalyst.
More specifically, when a catalyst agent is applied to, for example, the bone portion of the present catalyst carrier, it becomes a catalyst used in a chemical device or an automobile waste gas treatment device.

[Prior Art] A commercially available three-dimensional mesh-like ceramic porous body can be used as a catalyst by coating a bone portion with a catalyst agent. However, it is difficult to apply a sufficient amount of the catalyst agent because the bones are smooth and slippery. Also, ceramics are non-conductors,
It is difficult to apply the catalyst agent by electroplating, which limits the means for applying the catalyst agent. Further, since ceramics cannot be electrically heated, for example, when a catalytic reaction is carried out at a high temperature, the passing fluid for the catalytic reaction is separately heated to a high temperature, so that the heating device becomes large in scale.

JP-A-51-98690 discloses that the surface of a skeleton of a metal three-dimensional mesh-like porous body having a smooth surface is coated with, for example, metal powder and baked to roughen the surface of the skeleton. It is a catalyst coated with a catalyst agent. However, the roughening of the skeleton surface of this method is performed by electroless plating → surface treatment → coating of metal powder etc. → baking, and the roughening process is complicated,
Further, since the metal powder and the like are expensive, the catalyst carrier is also extremely expensive. Even if the roughened layer is formed on the surface of the smooth metal skeleton, the bond between the skeleton and the roughened layer is weak, and the roughened layer is easily peeled off when heating and cooling of the catalyst body are repeated.

The present inventors have studied a method for producing a porous body at low cost, and invented an iron porous body using an inexpensive iron powder or the like.
65884 (Japanese Patent Application Laid-Open No. 2-19405), Japanese Patent Application No. 63-165885 (Japanese Patent Application Laid-Open No. 2-19406), Japanese Patent Application No. 63-197853 (Japanese Patent Application Laid-Open No. 2-47206)
No.) and Japanese Patent Application No. 63-210642 (JP-A-2-61002).

The present inventors have further carried out research using these porous iron bodies as catalyst carriers, and have completed the present invention.

[Problems to be Solved by the Invention] That is, according to the present invention, the bone portion has a three-dimensional mesh shape and the pore diameter is 100 μm.
A pierced hole of 10 mm to 10 mm (hereinafter abbreviated as macro hole) is formed and the bone portion has a hole diameter of 10 μm to 100 μ
It consists of a rough sintered surface having m innumerable pores (hereinafter abbreviated as micropores), and when the catalyst agent is applied to the bone part,
A method for producing a catalyst carrier that allows a sufficient amount of a catalyst agent to be applied by a rough sintering surface, micropores, or the anchoring action of the catalyst agent that has penetrated into the micropores. Since the catalyst carrier is electrically conductive, a wide range of means for applying a catalyst agent such as electroplating is possible, and furthermore, the catalyst carrier can be directly energized or induction heated to bring the catalyst to a desired temperature. The present invention provides a catalyst carrier applicable to a compact device. The present invention also provides an inexpensive catalyst carrier using iron powder or the like that can be easily pulverized.

[Means for Solving the Problems] That is, the present invention provides (1) one or more selected from iron powder having an average particle size of 50 μ or less, iron oxide powder, and iron powder having a surface oxidized, or further The first step of producing carbon powder having an average particle size of 50μ or less to produce a base metal powder having the following carbon and oxygen contents, and kneading the base metal powder with a binder to thermally decompose the powder. Having a second step of applying to the skeleton of the porous porous mesh body, and a third step of heating the product of the second step to remove the thermally decomposable porous mesh body and further subjecting the coated material to self-reduction sintering , A method for producing a porous iron catalyst carrier [C]> 2.1, in which the iron skeletons form porous macropores and the iron skeletons are made of an iron sintered body having micropores [C]> 2.1 }… 1 4/3 ([C] -2) <[0] <4/3 ([C] +7) However, [C]: Carbon content of powder for base material (wt%) [O]: Mother The oxygen content (% by weight) of the powder for wood, and (2) average One or more selected from iron powder, iron oxide powder, and iron powder whose surface is oxidized, having a diameter of 50μ or less, and a thermal decomposition agent powder having an average particle size of 50μ or less, or further having an average particle size of A first step of producing a base material powder by mixing with carbon powder of 50 μm or less, and a second step of kneading the base material powder with a binder and applying the mixture to the skeleton of the thermally decomposable mesh-like porous body. And a third step of heating the product of the second step to remove the heat decomposing agent powder and the heat decomposable mesh-like porous body and further subjecting the adhered material to self-reduction sintering, the macro of iron bone parts being a porous body (3) A method for producing a porous iron catalyst carrier, wherein pores are formed and the iron bones are made of a sintered body of iron having micropores. 1 selected from salt powder
Or a thermal decomposition agent powder consisting of 2 or more, according to (2), a method for producing a porous catalyst carrier, and (4) self-reduction sintering, self-reduction heating to 800 ~ 1200 ℃. The method for producing a porous iron catalyst carrier according to (1), (2) or (3) above, which is sintering.

FIG. 1 is a diagram showing an enlarged example of a bone portion of a porous iron catalyst carrier of the present invention. That is, the catalyst carrier of the present invention is an iron bone part.
2 forms macro pores 1, and the iron skeleton is formed of a sintered body having a large number of micro pores 3. As will be described later, in the catalyst carrier of the present invention, a powder raw material is kneaded to apply the kneaded product to the skeleton of a thermally decomposable mesh-like porous body such as urethane oform or organic three-dimensional woven fabric (Arisawa Manufacturing Co., Ltd.) However, the pore size is 100 μm to 10 m by selecting the size of the mesh of the thermally decomposable three-dimensional mesh-like porous body.
It is possible to form m through-hole type macropores 1. Further, as will be described later, the catalyst carrier of the present invention uses a powder raw material containing C or O or a powder raw material containing a thermal decomposition agent powder, but CO generated in the process of self-reduction sintering or the like.
Pore size is 10 to 10 due to thermal decomposition of gas and thermal decomposition agent powder
Countless micropores of 0μ are formed in the iron bone.

In the catalyst carrier of the present invention, the bone portion forms macropores 1, and the bone portion has a rough surface and is a sintered body and has micropores 3. When applying,
Unlike the prior art, for example, JP-A-51-98690, it is not necessary to further form a roughening layer on the surface of the bone portion, and the catalyst agent is directly applied to the bone portion. A sufficient amount of the catalyst agent can be applied due to the anchoring action of the catalyst agent that has penetrated into the rough surface of the micropores and macropores, and the catalyst agent can be applied to the bone part with a strong force. Prevent peeling of the agent.

The catalyst agent to be applied to the catalyst carrier of the present invention, Pt, Pd, Rh
A white metal such as Cu, a copper group such as Cu, Ag, and Au, a rare earth element such as Nd, Ce, La, and Th, Mn, Cr, Ni, Al, Ba, or a compound thereof can be used. Further, also in the method of applying the catalyst agent, since the catalyst carrier is conductive, a coating means such as electroplating is also possible, and it is easy to raise the temperature by energizing or inductively heating the catalyst carrier, The coating temperature can be arbitrarily selected, and drying, baking, heat treatment, etc. of the catalyst agent after coating can be performed more easily than before.

Further, the catalyst body using the catalyst carrier of the present invention can easily heat the catalyst body to a desired temperature by directly energizing or inductively heating the catalyst carrier. Therefore, for example, the present invention can be used as a carrier of a catalyst for catalytic reaction at high temperature. When used, unlike the prior art, there is no need to separately heat the fluid for catalytic reaction, which simplifies the device or saves operating costs.

The bone portion of the catalyst carrier of the present invention has a large number of micropores, but since the matrix is made of tough iron, it has sufficient strength and toughness as a catalyst carrier. Further, as will be described later, the catalyst carrier of the present invention is produced through the second step of applying the kneaded material to the skeleton of the thermally decomposable three-dimensional network porous body,
When a thick skeleton is formed by adjusting the shape of the thermally decomposable three-dimensional mesh-like porous body and the coating thickness of the kneaded product, a porous catalyst carrier having further sufficient strength and toughness can be obtained. The strength, toughness, corrosion resistance, etc. of the bone portion of the catalyst carrier can be further improved by making the iron bone portion a bone portion containing an alloying element of alloy steel or stainless steel. In the present invention, Mn, Ni, P, Cr, Mo, Cu, Al, Si containing 1 or 2 or more alloy components of molten iron as necessary, and then iron powder crushed thereafter, the first described below. Although used as iron powder in the process, a catalyst carrier composed of bones containing these alloying elements can be obtained. The inclusion of alloying elements is also the first step described later,
For example, it can be achieved by adding and mixing the above alloy powder to iron powder containing no alloy element.

Next, a method for producing the catalyst carrier of the present invention according to claim (1) will be described.

In the first step of the manufacturing method, iron powder, iron oxide powder, iron powder whose surface is oxidized, and carbon powder having an average particle diameter of 50 μm or less are used.
A base material powder having the following carbon and oxygen contents is prepared.

[C]> 2.1} ... 1 4/3 ([C] -2) <[0] <4/3 ([C] +7 where [C]: carbon content of powder for base material (wt%) [O ]: Oxygen content of powder for base material (wt%) Next, in the second step, this mixed powder is used as a binder, for example, CM.
After kneading with an aqueous solution of C, polyacrylic acid, water glass, etc.,
The kneaded material is applied to the skeleton of a thermally decomposable mesh-like porous body, for example, urethane foam. The application can be performed by, for example, a spray method or a roll skies method.

Next, in the third step, the product of the second step is heated in a heat treatment furnace. For example, using a heat treatment furnace in an inert gas atmosphere,
When heated at 0 ° C for 10 minutes, the skeleton of the thermally decomposable three-dimensional network porous body is thermally decomposed and removed. The porous iron catalyst carrier of the present invention is obtained by further heating at 800 ° C. to 1200 ° C. and performing self-reduction sintering. As described above, according to the present invention, the base metal powder containing carbon and oxygen is used, and CO
A gas is generated, and a large number of micropores are formed in the bone part of the iron by the generation of this CO gas. Base material powder is [C]
In the case of> 2.1 and 4/3 ([C] -2)> [0], the number of micropores is small, which is not preferable as a catalyst carrier. Also [0]> 4/3
In the case of ([C] +7), the carrier strength of the molded product is weak.

In the present invention, the self-reduction sintering is performed at 800 to 1200 ° C. At 800 ° C or lower, the self-reduction of iron oxide does not occur sufficiently, and the strength of the porous metal body is low and it cannot be put to practical use. Further, at 1200 ° C. or higher, over-sintering occurs, the surface roughness of the bone portion disappears, and the micropores contract to reduce the performance as a catalyst carrier.

FIG. 2 is a diagram showing the relationship between [C] and [O] of the base material powder and the volume ratio of the micropores in the iron bone portion.

In the figure, A is an example of claim (1), but [C] of the powder for the base material and
By selecting [O], the volume ratio of micropores can be adjusted.

The iron powder for producing the catalyst carrier of the present invention may use expensive raw materials such as atomized iron powder and electrolytic iron powder, but iron powder having a carbon content of 2.1% or more has excellent pulverizability and is therefore inexpensive. It is preferable because it can be manufactured. In addition, iron powder with a [C] of 2.1% or more becomes iron powder whose surface is easily oxidized by wet grinding.

The base material powders of the present invention all have an average particle size of 50 μm or less. Unlike the general powder alloy sintering method, in the present invention, the kneaded product is applied to the skeleton of the thermally decomposable mesh-like porous body and fired without using a high-pressure press or the like. When the average particle size is 50 μm or more, the kneaded product does not become a slurry state and is difficult to be applied,
In addition, the bonding force between the sintered particles becomes insufficient.

Next, a method for producing the catalyst carrier of the present invention according to claim (2) will be described. In this method, the base material powder is formed of one or more selected from iron powder, iron oxide powder, and iron powder whose surface has been oxidized, a thermal decomposition agent powder, and carbon powder if necessary. ing. The average particle size of each powder is 50 μm or less, as in the case of claim (1). The thermal decomposition agent powder of this method refers to an organic powder such as a plastic powder, an organic polymer material powder, and sawdust, or a carbonate powder such as limestone powder. In the method described in claim (2), the catalyst support is manufactured by using the powder for a base material and performing the second step and the third step described in claim (1). The thermal decomposition agent powder can be decomposed in the third step and eliminated at the same time or by post-treatment, but the traces of decomposition and disappearance become micropores, further increasing the micropores in the iron bone part. It will be.

However, according to the knowledge of the present inventors, the mixing ratio of the thermal decomposition agent powder is
If it exceeds 50%, it is difficult to maintain the kneaded material in a good slurry state in the second step, and the coating property to the skeleton of the thermally decomposable three-dimensional network-like porous body becomes poor.

Therefore, it is preferable that the amount of the thermal decomposition agent powder mixed is 50% or less. Fig. 2B shows an example in which 50% plastic powder having an average particle size of 10 µ is mixed as the base material powder as the thermal decomposition agent powder, but by using the thermal decomposition agent powder, it is included in the bone part. It is possible to greatly increase the number of micro holes.

[Example 1] The powder for a base material shown in Table 1 was kneaded with an aqueous solution of CMC, and the pore diameter was 2 m.
100 mm x 100 mm x 10 mm by applying 1 mm thickness by spraying method to the skeleton of urethane foam of m, and conducting the heat treatment of Table 2.
A porous iron plate-shaped catalyst carrier was manufactured.

*: Volume ratio of micropores in bone part Table 2 also shows the state of pores in the obtained porous catalyst carrier. In each of the catalyst carriers, the bone portion formed porous macropores, and the iron bone portion was a sintered body having a rough surface and had a large number of micropores.

[Example 2] The catalyst carrier No. 2 in Table 2 was immersed in a platinum chloride solution, and then a current of 50 A was applied for 30 minutes, and the catalyst was directly heated to 600 ° C to produce a catalyst body. Using 4 sheets of this catalyst,
It was used as an oxidation catalyst in the reaction vessel shown in FIG. Although the mixed gas at room temperature was used as the processing gas, the catalyst carrier was
When directly heated to 0 ° C, the gas after treatment was about 200 ° C and the oxidation efficiency was 98%, indicating excellent catalytic performance.

Example 3 Surface-oxidized iron powder (C: 3.5%, Si: 0.01%, Mn: 0.8%, C) having an average particle size of 5 μ by wet pulverization after treating chromium-containing iron with granular iron
r: 10%, P: 0.01%, S: 0.005%, oxygen: 8%) were obtained. This surface oxidizes 50% volume ratio of plastic powder to iron powder (average particle size
10μ), mixed with CMC and water, dip-coated on ureta foam, and then heat treated (drying: 100 ℃ × 1hr, degreasing: 35
0 ℃ × 20 minutes, Self-reduction: 800 ℃ × 30 minutes, Sintering: 1100 × 30
Min., Nitrogen atmosphere) to produce a catalyst carrier. This catalyst carrier had a volume ratio of micropores in the bone portion of 55%.

This catalyst carrier was coated with a catalyst agent (aluminazole) of a kneading liquid of MnO ₂ or CuO powder, but the bone part of the catalyst carrier has a rough surface and has many micro bubbles, so the coating is easy. After coating, baking was performed at 800 ° C, but even if the catalyst agent was applied thickly, the catalyst layer did not peel off.

[Effect of the invention] In the catalyst carrier according to the method of the present invention, the three-dimensional mesh-shaped bone portion forms macropores. Therefore, when the catalyst agent is applied to the bone portion, the contact area between the fluid passing therethrough and the catalyst is increased. Results in a large catalyst body.

Since the bone part of the catalyst carrier according to the method of the present invention is a sintered body with a rough surface having micropores, it is not necessary to form a roughening layer on the bone part, and it is sufficient to apply the catalyst agent as it is. A catalyst agent having a different thickness can be easily applied.

Since the catalyst carrier according to the method of the present invention is conductive, it is possible to provide a means for applying a catalyst agent using conductivity, such as electroplating. Further, by directly energizing or inductively heating the catalyst carrier, the catalyst can be heated to the maximum catalytic reaction temperature by a simple method.

In the present invention, iron powder, iron oxide powder, surface iron oxide powder, and the like, which are easy to pulverize and are inexpensive, are used as the main powder, so that the raw material cost is low and therefore the manufacturing cost is low.

[Brief description of drawings]

FIG. 1 is a diagram showing an enlarged example of the bone portion of the catalyst carrier of the present invention, FIG. 2 is a diagram showing an example of the relationship between the powder for base material and the generation of micropores in the bone portion, and FIG. FIG. 3 is a diagram showing an example of use of a catalyst using the catalyst carrier of the present invention. 1: Macro pores, 2: Steel bone parts, 3: Micro pores, 4:
Catalyst, 5: processing gas, 6: catalyst reaction vessel, 7: power source for heating catalyst carrier.

Claims (4)

[Claims] 1. An iron powder having an average particle size of 50 μ or less, iron oxide powder, iron powder having an oxidized surface, or one or more kinds selected from them, or further mixed with carbon powder having an average particle size of 50 μ or less. Then, the mixture is mixed and the first step of producing a powder for a base material having a carbon and oxygen content of the following formula 1: Having a second step of adhering and a third step of heating the product of the second step to remove the thermally decomposable mesh-like porous body and further subjecting the adherend to self-reduction sintering, the bone portion of iron having a pore diameter of 100 μm Method for producing a porous iron catalyst carrier [C]> 2.1, which comprises a sintered body having through holes of -10 mm formed therein and the bone portion of the iron having a number of holes having a hole diameter of 10 μm to 100 μm. }… 1 4/3 ([C] -2) <[0] <4/3 ([C] +7) However, [C]: Carbon content of powder for base material (wt%) [O]: Mother Oxygen content (% by weight) of material powder 2. Iron powder, iron oxide powder, having an average particle size of 50 μm or less,
With one or two or more selected from iron powder whose surface is oxidized,
A first step of producing a base material powder by mixing a thermal decomposition agent powder having an average particle diameter of 50 μm or less, or carbon powder having an average particle diameter of 50 μm or less, and the base material powder as a binder. Second step of kneading and applying to the skeleton of the thermally decomposable network porous body, heating the product of the second step to remove the thermally decomposing agent powder and the thermally decomposable network porous body, and further self-reducing the coating material. And a third step of sintering, wherein the iron skeleton forms through holes having a pore diameter of 100 μm to 10 mm, and the iron skeleton has a pore diameter of 10 μm to 1
Method for producing a porous iron catalyst carrier comprising a sintered body having innumerable pores of 00 μm 3. The thermal decomposition agent powder is a thermal decomposition agent powder composed of one or more selected from organic powder and carbonate powder.
The method for producing a porous iron catalyst carrier according to (2) 4. The self-reduction sintering is self-reduction sintering in which the temperature is heated to 800 to 1200 ° C. (1) or (2) or (3)
Of a porous iron catalyst carrier described in 1.