JPH0811192B2 - Exhaust gas purification catalyst - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a catalyst body for exhaust gas purification, which is installed in an exhaust gas passage of a combustion device to oxidize and purify carbon monoxide, unburned gas, odorous substances and the like. .

2. Description of the Related Art A catalyst body for exhaust gas purification provided in an exhaust gas flow path of a combustion apparatus such as a petroleum stove or a gas stove has been practically used in the past, but in any case, the catalyst body is a porous body or a honeycomb body, Alternatively, it has a flat plate structure composed of a fiber braid, and is integrated or separated above the combustion part and installed horizontally (that is, at right angles to the flow direction of the exhaust gas).

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention In the above-described conventional configuration, in the flat catalyst body, the total amount of exhaust gas is collected here and purified by catalytic reaction. Since the catalyst body is located opposite to the combustion section, the radiant heat radiated from the upstream surface of the catalyst body, which has the highest temperature, is reduced to the combustion section and the combustion section becomes abnormal. The high temperature would cause problems such as flashback and runaway combustion. Therefore, in reality, the catalyst body is installed at a considerable distance from the combustion section, and exhaust gas cannot be collected in full due to the pressure loss of the catalyst body and leaks to the surrounding open section with less resistance. There was a drawback that purification of exhaust gas could not be completed completely.

The present invention eliminates the above-mentioned conventional drawbacks, when exhaust gas is installed in a combustion device, it almost completely collects exhaust gas and completes the purification reaction, and at the same time reduces heat reduction to the combustion part to reduce adverse effects on the combustion part. It is intended to provide a catalyst body for purifying exhaust gas for prevention.

Means for Solving the Problems Technical means used in the present invention for solving the above problems include a top plate having a cylindrical honeycomb-shaped catalyst cylinder, at least a bottom surface of which is convex downward. And constitutes a catalyst body.

Action The present invention, by the above means, the flow of the exhaust gas is promptly guided to the side catalyst cylinder by the convex portion of the top plate, the flow path resistance is reduced, and almost the entire amount of the exhaust gas reaches the catalyst layer for purification. While improving efficiency, reducing heat accumulation on the top plate to reduce the amount of radiant heat released from here, and by further dispersing the radiant heat emission direction from directly below to the ambient direction,
It is possible to reduce the thermal influence on the lower combustion section.

Embodiment An embodiment of the present invention will be described below with reference to the accompanying drawings.
In FIG. 1, 1 is a catalyst cylinder in which a honeycomb-shaped ceramic carrier is loaded with a catalytically active component containing platinum as a main component, and 2 is a ceiling made of a stainless steel plate mounted on the upper surface of the catalyst cylinder 1. The central portion of the plate is a protruding portion 3 having a substantially conical shape protruding downward.

When the above configuration is used in the combustion device, the catalyst cylinder 1 can be fitted on the combustion cylinder 4 and used, but the combustion exhaust gas (solid line arrow G) flows from the combustion cylinder 4 toward the top plate 2 above. , Are dispersed in the circumferential direction by the protrusions 3. Therefore, the top plate 2 is not significantly heated by the exhaust gas (G), and a vortex is unlikely to be generated here, so that the flow path resistance is small and the catalyst cylinder 1 is quickly reached. The catalyst cylinder 2 can have a large area relatively easily by adjusting the height within the range of the outer diameter of the combustion cylinder 4 so as not to cause a large pressure loss, and a catalyst with a low pressure loss can be obtained in a small space. be able to. The exhaust gas is completely purified by the catalyst cylinder 2 and is discharged to the surroundings in a clean state.

On the other hand, as indicated by a broken line arrow R, the radiant heat supplied from the combustion cylinder 4 or the radiant heat emitted from the protrusion 3 heated by the exhaust gas is thermally absorbed by the inclined wall surface of the protrusion 3. The part is reflected, and part of the part is emitted by the secondary radiation in a form dispersed in the peripheral direction rather than the direct downward direction. Therefore, the heat reduced from the top plate 2 toward the combustion tube 4 is significantly reduced, and a thermal adverse effect on combustion, for example, standing flame or incomplete combustion due to excessive vaporization in the wick type, and flame opening in the premixing type. It is possible to prevent abnormal conditions such as flashback to the vaporization chamber due to overheating of the section. Of course, the catalyst cylinder 1 is in a position parallel to the combustion cylinder 4, and the radiant heat from the catalyst cylinder 1 does not significantly affect the combustion cylinder 4.

Here, it is preferable that the top plate 2 is a metal plate having a high reflectivity of radiant heat from the lower part, but it is also possible to form the top plate 2 with a ceramic material having high heat resistance as shown in FIG. 3, for example. The above-mentioned effect can be sufficiently exerted even if the projection is formed by projecting at least only the lower surface of the top plate 2. Further, in the case where the top plate 2 is also provided with the communication hole 4 and the catalytically active component is carried on the surface, a part of the exhaust gas is dispersed in the circumferential direction by the projecting portion 3 in the same manner as described above, and a part thereof is Since it passes through the communication hole 4 and is discharged to the upper part, the opening area can be made sufficiently large, so that the influence of the pressure loss is further reduced.

Further, the shape of the projection 3 is the conical shape with a slight curve as shown in FIG. 1, which is most suitable for the flow, but it may be a conical shape with a linear inclination as shown in FIG. As shown, the communication hole 5 may be provided. Alternatively, as shown in FIG. 5, even if the shape is close to a hemisphere, the above-mentioned effect is exhibited in a satisfactory range.

When such a cylindrical catalyst cylinder 1 is used,
The surface of the catalyst cylinder 2 faces the circumferential direction, so that not only does the combustion cylinder 4 not be adversely affected as described above, but also the radiant heat from the catalyst cylinder 2 is dissipated in the circumferential direction, so that the heating and heating device It can also be used as a heat source. For example, when used in a radiant oil stove (see Fig. 2), the radiation efficiency (radiation heat release amount / total combustion amount) is about 30 in a normal oil stove.
%, The radiation efficiency was improved to about 45% by mounting the catalyst body having the catalyst cylinder 1 having a height of 50 mm. At the same core height, there was only a slight increase in the amount of combustion (normally 2153 kcal / h, but the installed product was 2188 kcal / h).

EFFECTS OF THE INVENTION As described above, according to the present invention, by forming a catalyst body by mounting a substantially cone-shaped top plate with at least the lower surface protruding downward on the upper surface of the cylindrical honeycomb-shaped catalyst tube, A large-area catalyst surface can be accommodated in a small space, and by smoothly distributing and guiding the flow of exhaust gas, it is possible to obtain a catalyst having a high purification capacity with a low pressure loss even though the collection rate is high.
In addition, the lower combustion section is not adversely affected by heat, and the heat radiation to the surroundings can be increased.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of an exhaust gas purifying catalyst body according to an embodiment of the present invention, FIG. 2 is a sectional view of an essential part showing an example of its use, and FIGS. 3, 4, and 5 show other examples. FIG. 3 is a cross-sectional view of a main part of an exhaust gas purifying catalyst body according to an example. 1 ... Catalyst tube, 2 ... Top plate, 3 ... Projection part, 4 ... Communication hole.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Masato Hosaka 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) Bibliography 62-199121 (JP, U)

Claims (2)

[Claims] 1. A catalyst body for purifying exhaust gas, wherein a catalyst plate having a cylindrical honeycomb shape is capped with a top plate at least the lower surface of which is convex downward. 2. The exhaust gas purifying catalyst body according to claim 1, wherein the top plate is also provided with a communication hole and carries a catalyst.