JPS59222214A - Reducing method of nox - Google Patents

Abstract

PURPOSE:To reduce NOx in a high temp. zone by using a catalyst carrying a platinum element and a transition metal on a perovskite type compound oxide. CONSTITUTION:The perovskite type compound oxide is expressed as a general formula ABO3, and the compd. SrFeO3, having Sr at the A site and Fe at the B site, is especially suitable. Platinum, which is comparatively resistant to poisoning, is suitably used as a platinum element. And nickel is suitable as a transition metal. Each amt. of Pt and Ni to be carried is preferably regulated to >=0.1wt%. By bringing the catalyst into contact with a gas contg. NOx under the inert or reducing atmosphere at 800-1,000 deg.C, NOx can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to equipment or equipment that generates gas containing NOx.

Conventional structure and its problems Conventional NOx reduction methods generally have problems with the use of catalysts at high temperatures due to poor heat resistance, and
There were problems such as poor toxicity.

2. Purpose of the Invention The present invention solves these conventional problems, and uses a catalyst with excellent heat resistance and toxicity resistance to reduce NO in a high temperature range.
The purpose is to reduce x (-).

Structure of the Invention In order to achieve this object, the present invention uses a catalyst in which a platinum metal element and a transition metal are supported on a perovskite type composite oxide. Perovskite type composite oxide is represented by the general formula ABO3, and the A site is La, Sr,
It is preferable to use Fe, Co, Mn, etc. for the B site. In the present invention, in particular, 5rFe is used, in which the A site is Sr and the B site is Fe.
The compound ○3 is suitable. As a white metal element,
rhodium.

Palladium, platinum, etc. are conceivable, but among these, it is better to use platinum, which is relatively resistant to poisoning. Further, as the transition metal, iron, cobalt, 2, 7 Kel, etc. can be considered, but nickel is suitable in the present invention.

This catalyst has platinum supported on 3rF e O3 in an amount of 0.1 cent by weight or more and nickel in an amount of 0.1 weight percent or more. NOx can be reduced by contacting this catalyst with a NOx-containing gas at 800 to 1000°C under an inert atmosphere or a reducing atmosphere.

Description of examples Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

In the figure, 1 is the catalyst according to this example, 2 is quartz wool, 3 is a reaction tube, and 4 is a heater. In this configuration,
The NOx-containing gas is brought into contact with the catalyst and NOx can be catalytically decomposed. Table 1 shows the composition of this catalyst, Tables 2 and 4 show NOx
An example of decomposition is shown. Table 3 also shows platinum in SrFeO3,
An example of NOx decomposition using a catalyst each carrying nickel alone will be shown. As will be seen, when platinum and nickel are supported alone, the NOx decomposition activity is low, and the catalyst in which platinum and nickel are simultaneously supported has a low NOx decomposition activity.
It can be seen that it is effective for x-ization. Next, an example of catalyst adjustment will be explained. Evaporate 2-5 g of 5rFe○s (into ■, add 2.5 m/in caustic soda,
Heated for 30 minutes. Next, 6.7 jj / of chloroplatinic acid
Add 2.6 ml of IJ aqueous solution and heat at 400°C for 30
Heating was performed for 1 minute. 7f]′i, a chloroplatinic acid aqueous solution was added, and the same heating was performed. Furthermore, nitric acid di.

Kel's 5. Add 2.6ml of ojj/l aqueous solution and heat to 400°C.
The operation of heating for 30 minutes was repeated twice. The catalyst prepared in this manner exhibits the activity for NOx decomposition as shown in Table 2. Further, when this catalyst was subjected to hydrogen reduction at 460°C, it exhibited the activity shown in Table 4.

Table 1 Table 2 Table 3 Table 4 Effects of the Invention As shown in Table 4, the present invention brings a NOx-containing gas into contact with a platinum-Ninochel-supported 5rFe03 catalyst at high temperatures in a reducing or inert atmosphere. In particular, it aims to reduce NOx. This catalyst has a niperobrite structure and supports platinum and nickel, so it has excellent heat resistance and can be used at temperatures close to 1000°C.

2 Catalytic decomposition of NOx is possible.

3. It is easy to mold into a shape suitable for the reaction system (equipment, equipment).

4 Perovskite type composite oxide S r Fe O
In addition to 3, you can arbitrarily select site A and site B.

6. Combinations of metals other than platinum to Esochel are possible.

6. The platinum used is less abundant than perovskite-type composite oxides, resulting in cost reduction.

[Brief explanation of the drawing]

The figure is a sectional view of a main part of a reaction apparatus using the NOx reduction method of the present invention. 1...Platinum-Ninokel-supported 5rFe○3゜Name of agent: Patent attorney Toshio Nakao and one other person83-

Claims (2)

[Claims] (1) A NOx reduction method in which a catalyst in which a platinum metal element and a transition metal are supported on a perovskite-type composite oxide is brought into contact with a No 2 -containing gas at a temperature of 800 to 1000° C. in a reducing atmosphere or an inert atmosphere. (2) Sr as a perovskite complex oxide
The NOx reduction method according to claim 1, wherein platinum is used as the F e O3 platinum metal element and nickel is used as the transition metal.