JPS5920386B2 - catalyst body - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a single carrier with a plurality of different kinds of catalyst materials (selectively performing each reaction) in order to be able to handle multiple reactions with a single catalyst material. An object of the present invention is to provide a catalyst supporting a catalyst.

In recent years, the applications of catalysts have expanded significantly, especially in the field of environmental pollution prevention.
It is thought that the demand far exceeds the demand in the petrochemical field, and today the purification method using catalysts has already been put into practical use as the most reliable method for purifying automobile exhaust gas.
It has received high praise.

In addition, the catalytic reduction method, which is the most promising method for denitrification technology, has entered practical test operation in some areas, and is expected to be in great demand at the practical stage.

In this field of environmental pollution prevention, a wide variety of ingredients,
All of them require conversion into harmless and stable components such as CO2, N2, and H2O, and the reactions involved are not just a single reaction of oxidation or reduction, but also contradictory reactions of oxidation and reduction. often occurs.

Typical examples of these are CO and HC in automobile exhaust gas.
At the same time as the oxidation reaction that converts CO□ and H2O, NO
x may be converted into N2 and 02 by a reduction reaction.

On the other hand, at present, both the catalyst body and the equipment are
We are preparing separate systems for oxidation and reduction, and are attempting to purify CO, HC, and NOx by connecting them.

In addition, even in flue gas denitrification, a small amount of sulfur component reduces the denitrification rate, so wet desulfurization is performed in the case of a large amount of sulfur in order to desulfurize in the previous stage, but adsorption desulfurization is also effective in the case of a small amount. Therefore, it is conceivable to set up the adsorption device and the denitrification catalyst device in two stages.

In order to remove or obtain the desired reactant by using multiple actions such as contradictory reactions or adsorption and reaction, in the conventional single aggregate catalyst using particles or pellets, mutual interaction is required. In order to carry out the reactions independently, catalysts suitable for each reaction are loaded into independent catalytic reaction apparatuses.

The present invention provides a catalyst for carrying out a plurality of such reactions using a single carrier.

The configuration of the present invention will be described in detail in Examples below.

Example 1 A glass cloth made of glass fibers is dealkalized by heat treatment with a strong acid to increase the proportion of silica component and improve heat resistance.A silica cloth carrier in which alumina is supported on the surface of the silica cloth is cut into strips. The surface of the product is divided into two in the longitudinal direction, and each part has a final weight of 0 per carrier weight.
．． A chloroplatinic acid aqueous solution formulated to support 4 wt% Pt is applied, and after passing through a non-supporting section of the required length, the final amount is 0.25 wt% per carrier weight.
After applying a mixed solution of ruthenium chloride and palladium chloride formulated to support Ru and 0.2 wt% Pd, it was dried at 120°C, reduced in a hydrogen stream at 350°C, and then fired at 500°C in air. Prepare a catalyst cloth.

FIG. 1 shows a diagram of the structure of this catalyst.

Here, 1 is a Pt-supported region, 2 is a non-supported region, and 3 is a Ru+Pd-supported region.

As shown in FIG. 2, the catalyst body 4 obtained using this flexible continuous carrier is placed around a perforated cylindrical body 5 made of a punched steel plate and having a Pt supporting area 1.
is the beginning of winding and the Ru+Pd supporting region 3 is the end of winding to form a catalyst layer.

A case 6 is provided outside the catalyst layer 4 with a space interposed therebetween to form a catalyst device.

The reaction gas is introduced from the cylindrical body 5, passes through the catalyst layer 4 in the radial direction from the opening thereof, is collected in one place by the case 6, and flows out to the outside.

This device contains CO at a concentration of approximately 2nd factor and CH4 equivalent of 100011
1) When HC of Ill concentration and the amount of oxygen necessary to completely oxidize them, as well as a reaction gas prepared by diluting LOppm of No with N2, were supplied at a space velocity of 50,0OOh-1, the CO purification rate was 95. %, HC purification rate of 85%
, the NO purification rate was 94%.

On the other hand, after loading the same amount of catalyst bodies carrying only Pt or only Ru+Pd into a similar device, we looked at the purification rates of CO, HC, and NO under the same measurement conditions. Both were over 90%, but NO
It was found that the value was minus 5% and that it was generated.

Furthermore, using only the Ru and Pd mixed catalyst, CO and HC were only purified by 40% at most, and NO was only purified by about 10%.

Example 2 As shown in Fig. 3, a carrier carrying 8 wt% of silica and alumina was prepared in the form of a belt on the surface of the same silica cloth base material as in Example 1, and the first 1/3 of the surface was Copper sulfate 7 prepared to have a final content of 10 wt% based on the supported weight is supported, and 3/4 of the remaining 2/3 is supported in an amount of 1.
Vanadium oxide 8 prepared to be 0 wt%,
And the remaining amount is O, swt% Pd and 10wt%
of nickel oxide 9 was supported, and the boundary between each catalyst metal was separated by a non-supporting portion 10 having a width of 30 to 40 crrL and not carrying any metal.

This catalyst cloth was placed in a device similar to that used in Example 1.
The part supporting copper sulfate is wound at the beginning, and the part supporting platinum and nickel oxide is wound at the end.

This device has NO50Qppm, NH3700ppH+
When a reaction gas containing 50 ppI of 5O2 and 1000 pp of 0O2 diluted with N2 was introduced into the reactor, NO purification rate was 90%, and S02 was purified by 95%.

Moreover, the NH3 concentration in the outflow gas was almost O.

- When the same reaction gas as above was measured under the same conditions on a silica cross carrier catalyst supporting only vanadium oxide, the purification rate of NO was 92%, while S02 was about 40%. NH36 degrees is 50ppmTh
It was accompanied by a smell.

The effects of the present invention are as described for each reaction in the previous examples, but in Example 1, CO
, This was achieved by allowing the oxidation reaction of HC to occur in an oxygen atmosphere, and then reducing NO with Ru+Pd after the oxygen was used up, and the reduction reaction was effectively carried out using the heat generated by the previous oxidation reaction. This is possible because the catalyst body of the present invention makes it possible to arrange exclusive catalyst materials in the same catalyst layer.

In addition, in Example 2, in order to first perform selective NO reduction with NH3 in the S02 mixed gas, S02 is adsorbed or passed through an undeposited copper sulfate catalyst layer, and then the remaining NO is removed with vanadium oxide. Selective reduction.

At this point, some NH3 remains and is normally discharged, but
It is undesirable as a malodorous component, and is deodorized by decomposition or O1 oxidation using the final Pt and nickel oxide catalyst material.

Although it is possible for NH3 to be oxidized to No again at this stage, the amount is less than 2 orders of magnitude compared to NO before the reaction, and does not overturn the No purification itself as a whole.

In this example, silica cloth was used as the base material of the carrier, but other inorganic fiber woven fabrics or mat-like materials made of inorganic fibers may also be used.

Furthermore, the base material is not limited to cloth or mat shape, but may be more preferable especially when exhaust resistance is a problem.

Further, the effects of the present invention may not be impaired by supporting an adsorbent instead of the supporting catalyst material, by supporting the adsorbent and the catalyst material on the same carrier, and thereby having both the adsorption function and the catalytic function.

[Brief explanation of drawings]

FIG. 1 is a structural diagram of a catalyst cloth showing one embodiment of the catalyst body according to the present invention, FIG. 2 is a half-sectional perspective view of a catalyst device using the catalyst cloth of FIG. 1, and FIG. FIG. 7 is a structural diagram of a catalyst cloth showing another example. 1.3,7,8.9... Catalyst material, 4...
... Catalyst body (catalyst layer).

Claims (1)

[Scope of Claims] 1. A catalyst body characterized in that a plurality of different types of catalyst substances are independently supported on the surface of a flexible continuous carrier. 2. The catalyst body according to claim 1, wherein the base material of the carrier is silica cloth.