KR0135141B1 - Deodorizing catalyst for microwave oven - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a catalyst which effectively improves deodorization reaction even at a relatively low temperature by coating a noble metal catalyst component on a ceramic carrier in an appropriate amount in a complex state by coating it on a wash coat material. In the noble metal catalyst supported on the inside of the coat layer, the mixing ratio of the γ-Al ₂ O ₃ : noble metal complex (Pt and Pd), which is a wash coat material, is 98.5-99.5: 0.1-1.5 wt% based on mass. Description of deodorization catalysts for ranges.

Description

Microwave Deodorization Catalyst

1 is a schematic diagram of a microwave oven structure.

2 is a schematic diagram showing air flow in a microwave oven.

FIG. 3 is an enlarged view of catalyst mounting attached to the exhaust port in FIG.

4 is a state diagram showing a ceramic catalyst, in which a is an overall state diagram, and b is an enlarged cross-sectional view of a dashed line portion in FIG.

5 is a flowchart showing an oxidation reaction state of exhaust gas.

6 is a graph showing the catalyst temperature characteristics of the exhaust port during operation of the microwave oven.

7 is a manufacturing process diagram of the catalyst according to the present invention.

8 is a odor emission characteristics according to the present invention.

9 is a gas purification characteristic of the present invention.

* Explanation of symbols for main parts of the drawings

1: cavity part 2: lamp

3: heater 4: micom part

5: door 6: button

7: exhaust port 8: cooling fan

9: inlet

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to catalysts for purifying exhaust gases of various combustors, and more particularly, to a deodorizing catalyst for a microwave oven capable of effectively improving the deodorizing reaction even at a relatively low temperature by coating a noble metal catalyst component on a carrier in an appropriate amount in a complex state. .

Generally, the microwave oven includes a lamp 2 illuminating the inside and a heater 3 serving as a cooking heat source in the cavity 1 having a space for cooking food, as shown in FIG. 3) the microcomputer unit 4 for automatically adjusting the operation time and output of 3), the door 5 for opening and closing the cavity unit 1, the door opening and closing button 6 for controlling the opening and closing of the door, and air. It is composed of an exhaust port (7) for exhausting, as shown in Figure 2, the air sucked by the cooling fan (8) installed in the front portion is sucked into the cavity through the inlet port (9) Air flow Since the water vapor and odor generated during cooking are purged through the deodorizing catalyst installed in the latch of the exhaust port as shown in FIG.

The deodorization catalyst mounted on the exhaust port is formed in such a manner that a precious metal (Pd, Pt, etc.) selected as an active ingredient on a ceramic carrier is supported on a wash coat layer made of γ-Al ₂ O ₃ as shown in FIG. It is composed.

In preparing such catalysts, ceramic powders (eg, SiO ₂ , MgO, Al ₂ O ₃ ) are generally mixed, molded, dried and sintered to obtain a carrier having a specific surface area of 1-2 m 2 / g. In order to increase the supporting property of the noble metal in the post-process on the carrier, the washcoat is coated with γ-Al ₂ O ₃ material, and then supported by reduction of the precious metal selected from Pd and Pt to obtain a deodorizing catalyst as shown in FIG.

When the deodorizing catalyst prepared in this way is attached to a microwave oven, the harmful and odorous components are oxidatively decomposed into CO ₂ and H ₂ O by reacting with O ₂ and CO _{2 in the} air as shown in FIG. That is, cooking odor is decomposed and removed by the following catalytic reaction.

In the above reaction, the oxidation reaction occurs at a high temperature (about 1,000 ° C.) or higher in the absence of a catalyst, but when the catalyst is used, the oxidation reaction is activated even at the exhaust gas discharge temperature (about 200 ° C.) to purify the odor component gas. Let's do it.

However, the above-mentioned conventional catalyst is oxidized at a temperature of 200 ° C. or higher, but when it is lowered to about 110-130 ° C. as shown in FIG. 6 during microwave operation, it is difficult to expect an efficient deodorization and gas purification rate.

Accordingly, the present invention has been made to solve the above-described problems, a catalyst capable of activating the deodorization reaction at a relatively low temperature by mixing a certain ratio of the noble metal catalyst component supported on the washcoat layer coated on the ceramic carrier The purpose is to get.

Hereinafter, the present invention will be described.

The present invention is a noble metal catalyst supported on a wash coat layer coated on a ceramic carrier, wherein the noble metal catalyst is a mixture of Pt (platinum) and Pd (palladium).

At this time, the mixing ratio of Pt and Pd is 5-15: 85-95wt% based on the mass, and the noble metal catalyst thus constructed is 98.5-99.5: 0.5-1.5wt based on the mass with respect to γ-Al ₂ O ₃ , a washcoat material. % (γ-Al ₂ O _3: Pt / Pd mass ratio).

7 is a process chart for producing the catalyst of the present invention, the flow chart of the present process is the same as the conventional one, but is different from the conventional composition of the noble metal composite and in a certain ratio with the washcoat raw material.

That is, the ceramic powder is mixed, molded, dried, and sintered to obtain a ceramic carrier, and Pt and Pd are mixed at 5-15: 85-95 wt%, and then the washcoat material (γ-Al ₂ O ₃ ) and 98.5-99.5 The product of the present invention is completed by mixing it with water at a ratio of 0.5-1.5 wt% and forming a gel, coating it on the ceramic carrier, drying and baking.

The deodorizing catalyst prepared as described above can effectively reduce the cooking smell by activating the deodorizing reaction even at a relatively low temperature (110-130 ° C.) during the grill cooking operation.

8 and 9 show the odor generation index and the gas purification characteristics during the grill operation (in this case, the cooked food was tested by cutting for 4 minutes: 24 minutes of cutlass). Compared to the conventional method, the gas purification property (Fig. 9) is increased by about 70% compared to the conventional gas purification rate (iso-C ₄ H ₈ ). Brought it.

In addition, the γ-Al ₂ O ₃ : noble metal complex (Pt / Pd) mass ratio is 98.5-99.5: 0.5-1.5wt%, Pt: Pd mass ratio in the present invention range (5-15: 85-95wt%) And comparative invention A (2-3: 97-98wt%) and comparative invention B (17-20: 80-83wt%) that is outside the scope of the present invention was compared as compared to the present invention as shown in Figure 9 (A, B) showed much lower gas purification rate (about 1/2).

As described above, by using the catalyst composition in which the precious metal is a compound of a certain ratio and is mixed with the wash coat material in a certain ratio, the catalyst having improved odor and gas purification characteristics can be obtained at a relatively low temperature compared to the conventional operation during grill cooking. It can be widely used in the deodorizing catalyst of microwave ovens and other cooking appliances.

Claims (2)

In the noble metal catalyst supported on the wash coat layer coated on the ceramic carrier, the mixing ratio of the γ-Al ₂ O ₃ noble metal complex (Pt and Pd), the wash coat material, is 98.5-99.5: 0.5- Microwave deodorization catalyst, characterized in that 1.5wt%. The deodorizing catalyst for a microwave oven according to claim 1, wherein the mixing ratio (100 fractions) of Pt: Pd is 5-15: 85-95wt% by mass.