JPS61249540A - Catalyst - Google Patents

Abstract

PURPOSE:To obtain the catalyst in which black catalyst powder is supported on a black carrier by supporting the Perovskite catalyst on a catalyst carrier, simultaneously by impregnating manganese nitrate, etc. into the fine holes of the carrier and then by blackening the carrier when burning. CONSTITUTION:The catalyst carrier of a honeycomb structure made of a heat resistant ceramic material such as cordierite, etc. is dipped in the slurry made by mixing the metallic salts assuming a black color when manganese nitrate, cobalt nitrate, etc. are calcined in the air, the particulates of the Perovskite composite oxide and aluminum nitrate. The catalyst carrier is then dried and burned to obtain the catalyst. The carrier of this catalyst is blackened by transi tion metallic particulates, so said carrier is moderately beautiful even if the black Perovskite compound 5 falls partially. Said carrier is most suitable for the use of a domestic oven 9, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is directed to a method for removing incompletely burned components and unburned components generated during combustion, as well as hydrocarbon components that cause odors generated during various types of cooking. The present invention relates to an exhaust gas purification catalyst provided therein.

BACKGROUND OF THE INVENTION Conventionally, there have been various types of catalyst bodies of this type. In other words, the catalyst supporting platinum group metals, which is the most common among them, is produced by impregnating a porous ceramic carrier with an aqueous solution containing platinum group metals, such as an aqueous solution of chloroplatinic acid, and then drying and calcining it. It is attached to the surface of the pores of the carrier as fine metal particles or fine metal oxide particles. Although platinum group catalysts have good activity, their disadvantage is that they are very expensive. It is known that transition metal oxides or perovskite composite oxides incorporating a portion of transition metals have the activity of a platinum pot if the particle size is made very small, but transition metal oxides alone have no resistance to high temperatures. In contrast, some complex oxides with a vergeskite structure have considerable activity and are also heat resistant. Therefore, if fine powder of these perovskite compounds is adhered to a carrier, it becomes an excellent catalyst, but the adhered fine powder is inevitably weak in strength and tends to partially fall off. Although only a small portion of the perovskite compound falls off and has little effect on activity deterioration, after the black peropskite compound falls off, the white carrier surface becomes exposed, which is aesthetically undesirable. In particular, it is necessary to solve this problem for household combustion equipment.

Problems that Pf1 is intended to solve As described above, conventional carriers are almost white or nearly white in color, and if the attached black powder falls off, it will be noticeable. The present invention has been made in view of this point, and an object of the present invention is to make the carrier itself black or a color close to black in advance.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention, when supporting perogeskite catalyst powder on a catalyst carrier of a honeycomb structure, simultaneously uses a white metal salt, such as manganese nitrate, which becomes black when fired in air. The solution is impregnated into the micropores of the honeycomb structure, and the carrier is blackened during firing. The resulting catalyst body has black catalyst powder supported on a black carrier.

Due to the above-described structure, even if some of the supported catalyst powder is missing, no abnormality is observed in the appearance of the zero-action +3A.

Further, since transition metal oxides are formed inside the pores of the catalyst carrier, the blackened catalyst carrier can greatly increase the catalytic oxidation ability compared to the non-blackened catalyst carrier.

Embodiment FIG. 1 is a model diagram showing an embodiment of the catalyst body of the present invention. In FIG. 1, a catalyst carrier 2 is a micropore existing in the catalyst carrier 1, and transition metal oxide fine particles 3 are supported on the inner wall surface thereof. A perovskite composite oxide 5 is firmly adhered to the outer surface 4 of the catalyst carrier 1 with alumina 6 produced by firing a supporting agent. As the supporting agent, a material such as colloidal alumina or aluminum nitrate, which becomes porous and has strong adhesive properties by firing, is used.

In the above structure, even if a part of the film of perogeskite composite oxide 5 and alumina 6 attached to the surface 4 of the catalyst body is lost due to some mechanical impact or contact, the underlying surface will remain black. There is no change in appearance at all.

An example of the method for producing this catalyst will be described below.

Fine particles of vergeskite composite oxide (""0.9Ce
o, l+ CoO3) Cobalt nitrate (co(No3)2
・6 H20) and nitric acid 7 /I/ Minik A, (A
I (NO3) 3 ・9 H20) in a weight ratio of 4:3
: Mix at a ratio of 2 parts and add water to make a slurry. Furthermore, to make the slurry stable, CMC, PVA
A cordierite honeycomb structure with micropores inside is immersed in the mixture, which has been adjusted to a predetermined viscosity by adding a small amount of the following ingredients. The soaked honeycomb structure was taken out, the slurry liquid remaining in the inner circle of the cells was blown away by wind pressure, and then heated at 100°C for about 1 hour.
After drying, firing is performed at 800°C for 5 m1n for 40 min.

FIG. 2 is an example of the application of the catalyst carrier of the present invention, in which the catalyst body is mounted in a gas cooker.

A catalyst body 7 having a honeycomb shape is installed at an exhaust gas outlet 9 above an interior 8 of the cooking appliance. A wire mesh heating element 10 is placed on the top surface of the cooking chamber 80, and is heated to red heat by a gas burner 11.

Further, at the lower part of the cooking chamber 8, a stand 13 for placing food 12 to be cooked, a tray 14 for receiving oil from the food 12, etc. are installed.

In the above cooking device, the food 12 is placed on the table 12, the gas burner 11 is ignited, the wire mesh heating element 10 is heated, and the food 12 is cooked by the radiation and hot exhaust gas generated. At this time, odor-containing hydrocarbons generated from the cooked food 13 pass through the catalyst body 7 installed at the exhaust gas outlet 9 together with the exhaust gas generated from the gas burner 11, and the hydrocarbons are purified.

Effects of the Invention The effects of the catalyst body of the present invention are as follows: (1) Since it is a catalyst body in which fine powder is attached, even if the perovskite fine powder supported on the surface is detached, the background color remains the same. This makes it aesthetically pleasing, making it especially suitable for use in household combustors.

(11) Since the catalyst body of the present invention forms transition metal oxides inside the pores of the catalyst carrier to cause blackening, the catalytic ability is greatly increased compared to a catalyst body using a catalyst carrier that does not blacken. can be done.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of a catalyst body according to an embodiment of the present invention, and FIG. 2 is a longitudinal sectional view of the catalyst body applied to a cooking appliance. 1... Catalyst carrier, 2... Micropore, 3
... Transition metal oxide fine particles, 5 ... Perovskite compound oxide, 6 ... Alumina. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
figure! Figure 2

Claims (3)

[Claims] (1) Metal salts such as manganese nitrate that turn black when fired in air, fine particles of perovskite compound oxides that have oxidation activity, and support materials that become porous and have strong adhesive properties when fired, such as colloidal alumina and aluminum nitrate. A catalyst body made by stirring and mixing a catalyst with water to form a slurry liquid, in which a honeycomb structured catalyst carrier made of a heat-resistant ceramic material with micropores inside is immersed, dried, and fired. (2) Heat-resistant ceramics include cordierite, T and γ
The catalyst body according to claim 1, which is alumina, mullite, zirconia, mullite-zircon, aluminum titanate, etc. (3) Metal salts such as manganese nitrate, cobalt nitrate, manganese acetate, and cobalt acetate are calcined in air to produce manganese dioxide (MnO_2) and tricobalt tetroxide (
The catalyst body according to claim 1, which exhibits a black color, such as Co_3O_4).