JPH0645002B2 - Cylindrical catalyst body and exhaust gas purification device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a catalyst body having a purifying effect on exhaust gas discharged from combustion equipment and the like, and an exhaust gas purifying apparatus using the same.

2. Description of the Related Art A combustion apparatus such as a stove that uses oil or gas as a fuel or a fan heater is equipped with a catalyst for purifying exhaust gas, and the one that completely oxidizes and purifies unburned components and carbon monoxide contained in exhaust gas Although it has been practically used in the past, in this case, the catalyst body has a flat plate structure composed of a porous body, a honeycomb body, or a fiber braid, and is integrated or separated above the combustion part and horizontally (that is, exhaust gas). It was installed at right angles to the flow direction).

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention In the above-described conventional configuration, in the flat plate-shaped catalyst body, the total amount of exhaust gas is collected here, and in order to purify by catalytic reaction, a tubular flow channel structure for guiding exhaust gas to the catalyst body is used. Since it must be installed side by side and the catalyst is located opposite to the combustion part, the radiant heat radiated from the upstream surface of the catalyst, which has the highest temperature, is reduced to the combustion part, and the combustion part becomes extremely hot. It caused 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 total because of the pressure loss of the catalyst body, and leaks to the peripheral release section with less resistance. There was a drawback that exhaust gas could not be completely purified.

In view of the above-mentioned problems of the prior art, the present invention provides a catalyst body for exhaust gas purification, which is excellent in exhaust gas collection performance and purification performance, and has no adverse effect on the combustion part, and an exhaust gas purification apparatus using the same. With the goal.

Means for Solving the Problems Technical means used in the present invention for solving the above-mentioned conventional problems include a tubular catalyst body having a large number of communication holes in its side wall,
While closing one end, increase the opening area of the communication hole on the closing side and increase the opening area of the communication hole on the release side, or make the opening area of the communication hole uniform and increase the wall thickness of the closing wall. The structure is made thinner on the release side.

Action The present invention, by the above means, almost completely collects the exhaust gas, completes the purification reaction by eliminating the slip and overflow of the gas, and at the same time reduces the thermal reduction to the combustion part to prevent the adverse effect on the combustion part. In addition, it has the effect of increasing the radiation efficiency by increasing the amount of radiation and radiation to the entire surface.

Embodiment An embodiment of the present invention will be described below with reference to the accompanying drawings. In FIG. 1, reference numeral 1 denotes a tubular catalyst body, which is formed by bending a honeycomb-shaped ceramic carrier containing silica and alumina as main components, and carrying an active component containing a white metal as a main component. The side wall has a large number of communication holes 2,
2'is drilled. A metal lid 3 is attached to one end of the tubular shape, that is, an upper end, and the other end, that is, a lower end is only supported by a metal frame body 4, and the tubular catalyst body 1 is opened. ing. Here, the communication hole 2 on the closed side, on which the lid 3 is mounted, has a small diameter and is densely provided, while the communication hole 2'on the release side has a large diameter. The hole walls forming the communication holes 2 and 2'have almost the same thickness, and therefore the closed side where the small diameter communication hole 2 is bored is opened from the release side where the large diameter communication hole 2'is bored. The area is getting smaller. An example of a petroleum stove equipped with this cylindrical catalyst body 1 is shown in FIG. A combustion cylinder 7 is provided at the center of the box 5 and the rear surface of which is surrounded by a reflector plate 6. Combustion cylinder 7
1, the tubular catalyst body 1 shown in FIG. 1 is disposed, but the release side end is opposed to the combustion cylinder 7, and the closed side is fixed to the top plate 8.

Here, the operation will be described in detail. The fuel burns in the combustion cylinder 7, and a part of the generated heat is dissipated to the surroundings from the outer wall of the combustion section 7. On the other hand, the exhaust gas containing unburned components and carbon monoxide which have not been completely combusted in the combustion cylinder 7 is discharged to the upper part together with the heat which has not been recovered. Here, the tubular catalyst body 1 is provided upright on the upper portion of the combustion cylinder 7, the upstream side thereof is opened, and the downstream end portion is closed by the lid body 3, so that it is shown in FIG. As described above, after the exhaust gas (indicated by the arrow) flows inside the cylindrical catalyst body 1 substantially parallel to the wall surface,
Some of them gradually bend the flow path, and some of them bend the flow path after colliding with the lid body 3 and pass through the communication holes 2, 2 ′, which are the only openings, and are discharged to the surroundings. It During that time, most of the heat of the exhaust gas is recovered while passing through the communication holes 2 and 2 ', and the combustible components are also completely oxidized to carbon dioxide and water by the oxidizing action of the catalyst, so that the temperature is clean and at low temperature. Exhausted as exhaust gas. By the way, since the exhaust gas flowing into the tubular catalyst body 1 rises at a certain flow rate,
The center of the air flow concentrates on the upper part, and tries to pass through the communication hole 2 in the vicinity of the closed side end closed by the lid 3. In such a case, the contact time with the exhaust gas in the communication hole 2 becomes short, and the exhaust gas passes through without being completely purified, leaving unburned components and carbon monoxide remaining in the exhaust gas. This causes a phenomenon of so-called slip, which is discharged. Here, by changing the diameters of the communication holes 2 and 2 ', the diameter of the communication hole 2 is reduced in the upper part on the closed side and the diameter of the communication hole 2'is increased in the lower part on the release side, so that the flow resistance is increased in the upper part. Is increased to avoid concentration of the exhaust gas flow and to disperse the exhaust gas into the lower communication hole 2 ', so that flammable component slip is avoided and the entire area of the communication holes 2 and 2'acts effectively. Can be made.
Although the exhaust gas to the upper part is still inevitable in this way, since the diameter of the communication hole 2 is sufficiently small, the contact state with the exhaust gas is promoted, and in both the reaction of the combustible component and the heat exchange of the exhaust gas. , Can be fully completed.
On the other hand, in the large diameter communication hole 2'in the lower part, the contact with the exhaust gas is somewhat reduced due to the large diameter, but the flow rate of the exhaust gas has already decreased and it is in a state where sufficient contact time can be secured. The major drawbacks of are more than compensated. Thus, since the exhaust gas passes through the tubular catalyst body 1 in its entirety and has a resistance and a contact time according to the flow velocity, slippage of harmful components as in the conventional case is eliminated. On the other hand, in terms of heat, the tubular catalyst body 1, which is the largest heat recovery / heat radiating body, is located in the direction perpendicular to the combustion cylinder 7, and is dispersed in the circumferential direction rather than the direction directly below the combustion cylinder 7. Radiant heat is released in the form. Therefore, the heat reduced from the tubular catalyst body 1 to the combustion tube 7 is significantly reduced, and a thermal adverse effect on combustion, for example, a stand flame or runaway combustion due to an excessive vaporization amount in the wick type, or a flame in the premixing type. An abnormal condition such as flashback to the vaporization chamber due to overheating of the mouth can be prevented. In addition, the heat radiation from the side wall of the tubular catalyst body 1 heated by the heat of the exhaust gas or the heat of combustion of the unburned component is reflected directly or by the reflecting plate 6,
Both are supplied to the front and can be used for heating, heating, drying and the like. Therefore, the heat that has been conventionally dissipated as convective heat can be recovered and taken out as radiant heat. Utilization efficiency for heating and heating by radiation can be increased by using the tubular catalyst body 1. . In order to improve this radiation efficiency, the tubular catalyst body 1
Is preferably made of a ceramic material having high radiation efficiency, and a honeycomb body having communication holes 2 and 2'may be used.

Further, here, the diameters of the communication holes 2 and 2'are changed, but the opening density may be changed while keeping the same diameter. In this case, with respect to the flow velocity of the communication hole 2 on the closed side. The size of the diameter must be selected so that slip does not occur. Further, in the above-mentioned embodiment, the tubular catalyst body 1 is provided separately from the combustion cylinder 7. However, as long as there is no thermal influence from the tubular catalyst body 1, as shown in FIG. It is also possible to provide the flat catalytic body 9 in which the closed side end portion is provided with a communication hole 9'having a diameter smaller than that of the communication hole 2 having a smaller diameter or a smaller opening area. . In this case, from the viewpoint of effective use of the radiant heat, it is preferable that the load on the planar catalyst body 9 is not too large, and it is desirable to appropriately select the area ratio with the tubular catalyst body 1.

Further, the tubular catalyst body 1 does not necessarily have to have an integral structure in which the communication holes 2 and 2'of two specifications (or more) are formed, and as shown in FIG. 5, the communication hole 2 having a small diameter is formed. Installed downstream cylinder 10 and upstream cylinder 1 having a large diameter communication hole 2 '
0'and 0'may be stacked in series, and more stages may be provided if necessary. In addition, the tubular catalyst body 1
As the carrier of, in addition to the extruded ceramic honeycomb, it is also possible to use a braided body of heat-resistant fiber such as silica fiber or a porous metal body. Since the braided body has a small heat capacity, a small amount of heat can be used at an effective temperature. The temperature can be raised up to, and the effect at the time of starting can be accelerated. In addition, since the carrier is lightweight and highly flexible, it is strong against impact and has a cylindrical shape.
There is an advantage that it can be easily processed into a rectangular shape or other shapes. Further, in the case of a metal porous body, the inferior radiation efficiency can be improved by a method such as ceramic spraying, and the shape of the communication holes 2, 2'can be processed arbitrarily, so that the tubular catalyst body is superior in terms of appearance. Can be configured.

The case where the wall thickness of the tubular catalyst body 1 is uniform has been described above, but in addition to this, as shown in FIG.
The diameter and opening density are constant, and the same effect can be obtained even when the thickness is changed up and down. That is, by increasing the wall thickness on the closed side and decreasing it on the open side,
On the closed side where the wall thickness is large, the resistance becomes large, and the flow path of the communication hole is eliminated.Therefore, exhaust gas is dispersed to the open side, and even on the closed side where the flow velocity is large, it reacts completely without causing combustible components to slip. And heat can be recovered. Here, the outer circumference of the cylindrical catalyst body 1 is made upright and inclined toward the inner circumference side, but the opposite effect can be obtained without any trouble. Further, similarly to the case shown in FIG. 5, a method of stacking multiple stages of cylinders of varying thickness in series is also possible.

Further, the function of the tubular catalyst body 1 is not only to purify unburned components and carbon monoxide, but also to carry catalysts for purifying, decomposing and reducing nitrogen oxides (nox) and sulfur oxides (socks). However, the above effect is not impaired.

EFFECTS OF THE INVENTION As described above, according to the present invention, one end of a tubular catalyst body having a large number of communication holes in its side wall is closed, and the opening area of the communication hole on the closed side is reduced, so that the communication hole on the release side is formed. By increasing the opening area, or by making the opening area of the communication hole uniform and making the wall thickness thick on the closed side and thin on the open side, the exhaust gas is almost completely collected and the gas It eliminates slips and overflows, completes the purification reaction, and at the same time reduces the thermal reduction to the combustion part to prevent adverse effects on the combustion part, and also has the effect of increasing the amount of heat radiated to the front surface and increasing the radiation efficiency. It is possible to provide a tubular catalyst body and an exhaust gas purification method using the same.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a tubular catalyst body according to an embodiment of the present invention, FIG. 2 is a front view of a combustion instrument using an exhaust gas purifying device using the tubular catalyst body, and FIG. FIG. 4 is a partial cross-sectional view of a combustion instrument of another embodiment using the exhaust gas purifying apparatus of the present invention, and FIGS. 5 and 6 are perspective assembly views of a tubular catalyst body of another embodiment of the present invention. It is a figure and a longitudinal cross-sectional view. DESCRIPTION OF SYMBOLS 1 ... Cylindrical catalyst body, 2 2 '... Communication hole, 3 ... Lid body, 4 ... Frame body, 7 ... Combustion cylinder, 9 ... Planar catalyst body, 9' ... Communication hole, 10
... downstream cylinder, 10 '... upstream cylinder.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Masato Hosaka 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) References JP-A-64-63043 (JP, A)

Claims (5)

[Claims] 1. A tubular catalyst body having a large number of communicating holes in a side wall, one end of which is closed, and the opening area of the communicating hole is smaller at the closed end and larger at the release side. 2. The tubular catalyst body according to claim 1, wherein the diameter of the communication hole is small on the closed side and large on the open side. 3. The tubular catalyst body according to claim 1, wherein a plurality of tubular bodies having different opening areas are arranged in series. 4. A tubular catalyst body having a large number of communication holes in a side wall, one end portion of which is closed, and the wall thickness of which is large on the closed side and thin on the open side. 5. The method according to claim 1, with respect to the outflow direction of the exhaust gas,
An exhaust gas purifying device in which the open side ends of the tubular catalyst bodies according to 2, 3, or 4 are arranged to face each other.