JP2000039115A - Catalytic combustor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the size of a catalytic combustor by alternately providing pluralities of catalytic bodies and heat receiving sections, in such a way that the heat receiving sections are substantially faced to the vent holes of the catalytic bodies and the heat receiving sections are united with a heat exchanger having a passage for a fluid to be heated. SOLUTION: A plurality of catalytic bodies 2 and heat receiving sections 3 are alternately arranged in such a way that the sections 3 are faced to the vent holes of the bodies 2, so that the sections 3 may readily receive radiation from the bodies 2 and formed integrally with a heat exchanging section 5 having a passage 6 for a fluid to be heated. Therefore, the surface areas per unit volume of the catalytic bodies 2 can be increased and the radiation heat transfer to the heat receiving sections 3 from the bodies 2 is accelerated. In addition, the surface temperatures of the bodies 2 which are usually apt to become higher when the combustion amount is large can be suppressed by daringly suppressing burning reactions in the catalytic bodies 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention mainly relates to home use,
Alternatively, the present invention relates to a catalytic combustion device applied to hot water supply and heating for business use.

[0002]

2. Description of the Related Art A catalytic combustion apparatus has been proposed in which a catalytic body in which a noble metal catalyst such as platinum or palladium is supported on a base material such as cordierite is catalytically burned, and heat generated during the combustion is used for heating or the like (eg, for example). And Japanese Patent Application No. 4-302347 (JP-A-6-147419).

[0003] A heat exchange section is provided on the upstream side of the honeycomb catalyst body so as to receive radiation from the catalyst body. At the start of catalytic combustion, flame is burned by a preheating burner to activate the catalyst body at an activation temperature. After heating as described above, the supply of the mixed gas was stopped to extinguish the flame of the preheating burner, and the mixed gas was supplied again to perform catalytic combustion.

[0004]

However, such a conventional catalytic combustion apparatus has the following problems. First, since catalytic combustion has a low combustion temperature, an attempt to increase the amount of heat exchange increases the size of the catalyst body, making it difficult to reduce the size of the entire apparatus. When the catalyst body is large, the combustion stability tends to be insufficient particularly at a low combustion amount, and it becomes difficult to expand the combustion amount variable range. On the other hand, when trying to reduce the size of the catalyst body to reduce its size, there has been a problem that the temperature of the catalyst body rises and exceeds the heat resistance limit. Further, after the flame is burned by the preheating burner at the start of catalytic combustion, the control of the method of stopping the supply of the mixed gas to extinguish the flame of the preheated burner and supplying the mixed gas again to perform catalytic combustion tends to be complicated. In addition, there is a problem that nitrogen oxides (NOx) are generated during flame combustion.

The present invention has been made in consideration of the problems of the conventional catalytic combustion device, and has as its object to provide a high-load type heat exchange integrated type catalytic combustor, and to provide a catalytic combustion device capable of downsizing the equipment. It is assumed that.

[0006]

According to the present invention, there is provided a mixed gas supply unit for mixing fuel and air, a gas permeable catalyst provided downstream of the mixed gas supply unit. A heat receiving portion substantially facing the vent of the catalyst body; a plurality of sets of the catalyst body and the heat receiving portion being alternately provided; and the heat receiving portion being integrated with a heat exchange portion having a passage for the fluid to be heated. A catalytic combustion device characterized in that:

[0007]

Embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment) FIG. 1 is a cross-sectional view of the first embodiment, and FIG. 2 is a cross-sectional view of the first embodiment along AA. The main parts of the catalytic combustion apparatus according to the first embodiment include a mixed gas supply unit 1, a catalyst unit 2, a heat receiving unit 3, a partition plate 4, a heat exchange unit 5, a fluid passage to be heated 6, a second catalyst unit 7, a preheating heater. 8, preheating heater support 9, preheating heater holder 10, exhaust heat recovery unit 1
1. Exhaust gas outlet 12 Reference numeral 100 denotes a combustion chamber for storing the catalyst 2. The catalyst body 2 and the second catalyst body 7 are made of a cordierite honeycomb having air permeability and support a noble metal catalyst such as palladium or platinum. Gas passing direction (venting direction) in the catalyst body 2;
In the combustion chamber 100, the catalyst body 2 is installed so that the flow direction of the mixed gas upstream of the catalyst body 2 is substantially perpendicular, and the flow direction of the gas mixture in the second catalyst body 7 is parallel to the flow direction of the mixed gas. The second catalyst body 7 is provided so that Therefore, the ventilation direction in the catalyst body 2 is perpendicular to the ventilation direction in the second catalyst body 7. The heat receiving section 3 faces the vent of the catalyst body 2 so as to easily receive the radiation from the catalyst body 2,
A plurality of sets of catalyst bodies 2 and heat receiving sections 3 are alternately provided. The heat receiving section 3 is integrated with the heat exchange section 5 having the fluid passage 6 to be heated. The exhaust heat recovery unit 11 is provided on the downstream side of the second catalyst body 7 and is integrated with the heat exchange unit 5 like the heat receiving unit 3.

Next, the operation of the present embodiment having such a configuration will be described. First, at the start of combustion, the preheater 8 is energized to preheat the second catalyst body 7 to an activation temperature or higher, and then the energization of the preheater 8 is stopped, and the mixed gas is supplied from the mixed gas supply unit 1. The catalytic combustion is started by the two catalysts 7. Thereafter, the catalyst 2 is heated by the radiation from the second catalyst 7, and the catalyst 2 also starts catalytic combustion. The mixed gas flows in one direction in the catalyst body 2 by the partition plate 4 (see arrows). During the catalytic combustion, the catalyst body 2 and the second catalyst body 7 are glowed red, and radiant energy is emitted. This radiant energy is absorbed by the heat receiving unit 3 and the like, and is converted into heat energy again.
Radiated heat transfer to Further, the heat energy is transferred from the heat exchange section 5 through the heated fluid passage 6 by heat conduction to the heated fluid in the heated fluid passage 6 by convective heat transfer. Since the radiant heat transfer does not disturb the flow, the combustion reaction in the catalyst body 2 and the second catalyst body 7 is not hindered, and the combustion stability is ensured even when the amount of heat exchange with the fluid to be heated is increased. Can be.

[0010] By providing a heat receiving portion 3 facing the ventilation hole of the catalyst body 2 and providing a plurality of sets of the catalyst body 2 and the heat receiving portion 3 alternately, the surface area of the catalyst body 2 per unit volume is increased, To promote radiant heat transfer from the medium 2 to the heat receiving unit 3 and to intentionally suppress the combustion reaction in the catalyst body 2, and to reduce the catalyst surface temperature of the catalyst body 2, which usually tends to become high at a high combustion amount. Can be. The gas components that did not react in the catalyst body 2 are removed from the second catalyst body 7 such that the gas flow direction in the second catalyst body 7 is parallel to the flow direction of the mixed gas.
Completes the combustion reaction.

By making the ventilation direction in the catalyst body 2 perpendicular to the ventilation direction in the second catalyst body 7, the flow of the mixed gas is disturbed, and the contact between the catalyst body 2 and the second catalyst body 7 is prevented. Increasing the time can increase the combustion reactivity.

The combustion gas that has passed through the second catalyst body 7 is discharged to the outside through an exhaust gas outlet 12 after exhaust heat is recovered by an exhaust heat recovery unit 11. In the exhaust heat recovery unit 11, the radiant heat transfer from the second catalyst body 7 is also added, and the heat energy there is also transferred to the fluid to be heated in the fluid passage 6 to be heated, which is effective for high efficiency.

[0013] Compared to a catalyst body in which a catalyst is supported on a thin plate-shaped base material, the catalyst body 2 in which a catalyst is supported on a honeycomb lattice-shaped base material having air permeability increases the strength against thermal stress and the like. , And the service life can be improved.
When the combustion amount is high, the catalyst body 2 which is usually easily heated
Since the surface temperature of the catalyst can be reduced to a temperature lower than the heat-resistant limit temperature and a high-load-type heat exchange integrated catalytic combustor can be realized, the size of the equipment can be reduced.

The heat exchange unit 5 such as the heat receiving unit 3 and the exhaust heat recovery unit 11
By coating the heat receiving surface side with a high radiation material, the efficiency of heat transfer from the catalyst body 2 and the second catalyst body 7 can be improved.

By arranging two second catalyst bodies 7 in the flow direction and providing an electric or other preheater 8 between the two second catalyst bodies 7, heat radiation from the preheater 8 is suppressed,
The time until the second catalyst 7 is preheated to the activation temperature can be reduced. Unlike the conventional method in which the flame is burned with a preheating burner at the start of catalytic combustion, the supply of mixed gas is stopped to extinguish the flame of the preheating burner, and the mixed gas is supplied again to perform catalytic combustion. Is easy,
NOx is not generated at the time of flame combustion.

(Embodiment 2) FIG. 3 is a sectional view of Embodiment 2. In the first embodiment, the heat receiving portion faces the air hole of the catalyst body 2 substantially vertically, but in the second embodiment, the heat receiving portion 3 faces the air hole of the catalyst body 2 almost obliquely.

The operation is almost the same as that of the first embodiment. However, in the second embodiment, the radiant heat transfer amount is changed by obliquely facing the vent heat receiving portion 3 of the catalyst body 2.
Since the reaction amount in the catalyst body 2 can be increased or decreased, the ratio of the combustion reaction in the catalyst body 2 and the second catalyst body 7 can be easily optimized, and the surface temperature of the catalyst body 2 and the second catalyst body 7 can be made uniform at a high combustion amount. And high load combustion can be realized.

In the first embodiment, the gas passage direction is perpendicular to the gas passage direction in the second catalyst. In the second embodiment, however, the gas passage direction is oblique by about 30 degrees. , Substantially vertical.

(Embodiment 3) FIG. 4 is a sectional view of Embodiment 3. In the first embodiment, the preheater 8 is provided between the two second catalyst bodies 7, but in the third embodiment, the preheater 8 is provided between the catalyst body 2 and the second catalyst body 7. I have.

The operation is substantially the same as that of the first embodiment. However, in the third embodiment, not only the second catalyst 7 but also the catalyst 2 can be preheated when the preheating heater 8 is energized. The time required for catalytic combustion in the medium 2 can be reduced.

[0021]

As described above, according to the catalytic combustion device of the present invention, the following effects can be obtained.

That is, by providing a heat receiving portion facing the vent hole of the catalyst body, and alternately installing a plurality of sets of the catalyst body and the heat receiving portion, the surface area of the catalyst body per unit volume is increased, and the heat receiving portion from the catalyst body is received. While promoting radiant heat transfer to the part, darely suppress the combustion reaction in the catalyst body, at the time of a high combustion amount, usually reduce the catalyst surface temperature of the catalyst body, which is likely to be high temperature, to keep it below the heat resistant limit temperature, Since it is possible to realize a high-load-type heat exchange integrated catalytic combustor, the size of the equipment can be reduced.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a catalytic combustion device according to a first embodiment of the present invention.

FIG. 2 is a sectional view of the catalytic combustion apparatus according to the first embodiment of the present invention, taken along line AA.
Sectional view

FIG. 3 is a sectional view of a catalytic combustion device according to a second embodiment of the present invention.

FIG. 4 is a sectional view of a catalytic combustion device according to a third embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 2 catalyst body 3 heat receiving section 5 heat exchange section 6 fluid passage to be heated 7 second catalyst body 8 preheater 11 exhaust heat recovery section 100 combustion chamber

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Akira Maenishi 1006 Kadoma Kadoma, Osaka Pref. Matsushita Electric Industrial Co., Ltd. (72) Inventor Hironao Numamoto 1006 Kazuma Kadoma, Kadoma City, Osaka Prefecture F-term in Matsushita Electric Industrial Co., Ltd.

Claims (8)

[Claims] 1. A mixed gas supply unit for mixing fuel and air, a gas permeable catalyst provided downstream of the mixed gas supply, and a heat receiving unit substantially facing a ventilation hole of the catalyst. And a plurality of sets of the catalyst body and the heat receiving unit are alternately provided, and the heat receiving unit is integrated with a heat exchange unit having a passage for the fluid to be heated. 2. The catalytic combustion device according to claim 1, wherein a second catalytic body is provided downstream of the catalytic body. 3. The catalytic combustion device according to claim 1, wherein a gas flow direction in a space upstream of the catalyst body in the combustion chamber storing the catalyst body and a gas passage direction in the catalyst body are substantially perpendicular. 4. The catalytic combustion apparatus according to claim 2, wherein a gas passage direction in the catalyst body and a gas passage direction in the second catalyst body are substantially perpendicular. 5. The catalytic combustion device according to claim 2, wherein an exhaust heat recovery section is provided downstream of the second catalyst body. 6. The heat receiving surface of the heat receiving portion and the heat receiving surface of the exhaust heat recovery portion are covered with a high radiation material.
A catalytic combustion device according to any of the preceding claims. 7. The catalytic combustion according to claim 2, wherein the second catalyst body is provided at two places along a gas flow direction, and a preheater is provided between the two second catalyst bodies. apparatus. 8. The catalytic combustion device according to claim 2, wherein a preheater is provided between the catalyst body and the second catalyst body.