JPS61291820A - Catalytic burner - Google Patents

Abstract

PURPOSE:To use in combination heating using a hot air flow and that using far infrared radiant rays to increase the space heating effect by installing a second combustion catalyst accommodated in a burner case made of a heat resisting metal on the forward surface of a first combustion catalyst. CONSTITUTION:A first combustion catalyst 9 carrying a first oxidizing catalyst 8 on a honey-comb heat resisting ceramics is installed within a combustion cylinder 1 made of a heat resisting metal. A second combustion catalyst 15 carrying a second oxidizing catalyst 14 on a heat resisting porous ceramic fiber assembly accommodated in a burner case 10, is installed on the forward surface of said first combustion catalyst 9. Fuel premixing air is subjected to catalytic combustion on the first combustion catalyst. By the resulted hot exhaust gas flow, the second combustion catalyst 15 is heated, and the heat- exchanged hot exhaust gas flow is discharged as hot air flow. On the other hand, the second combustion catalyst 14 reaches the activation temperature by the hot exhaust gas flow from the first combustion catalyst 9, and the catalytic combustion is carried out and the radiation of far infrared rays is obtained. Accordingly, the hot air flow excellent in the space heating ability and comfortable radiant rays are obtained simultaneously.

Description

Detailed Description of the Invention: Industrial Application Field The present invention supplies gaseous fuel such as city gas to a combustion catalyst body, performs catalytic combustion using combustion air, and uses the generated heat as radiant heat or hot air. catalytic burner.

BACKGROUND OF THE INVENTION As shown in FIG. 2, this type of catalytic burner supplies gas fuel to a pad-shaped combustion catalyst A in which an oxidation catalyst is supported on a heat-resistant porous ceramic fiber aggregate. Catalytic combustion was performed at 400-500'C over the entire surface of medium A, and about 40-50% of the generated heat was used as far-infrared radiation.

Problems to be Solved by the Invention When a catalytic burner using the above-mentioned conventional technology is used as a heating device, far-infrared radiation alone is insufficient for heating the room and inner metal body, especially when the catalyst burner for combustion is used as a heating device. The amount of radiation at a certain distance from the combustion surface is inversely proportional to the square of the distance, so the heating effect is considerably reduced. As a result, it is inevitably evaluated only for its function as a spot heater, and the low N
ox, low c.

Evaluation of the cleanliness of exhaust gas also tends to be neglected.

The present invention solves these conventional problems, and aims to add hot air to increase the heating effect while maintaining far-infrared radiation while maintaining exhaust gas cleanliness.

Means for Solving the Problems In order to solve the above problems, the catalytic burner of the present invention has the following features:
A first combustion catalyst body in which a first oxidation catalyst is supported on a honeycomb-shaped heat-resistant ceramic is installed in a combustion cylinder made of heat-resistant metal that has a mixer for fuel gas and combustion air at the rear. A second combustion catalyst body in which a second oxidation catalyst is supported on a heat-resistant porous ceramic fiber aggregate is installed in front of the combustion chamber.

Effect: With the above configuration, the present invention catalytically burns the fuel premixture mixed in an appropriate ratio in the mixing device on the first combustion catalyst body, and the obtained hot exhaust gas flow is applied to the burner case. The housed second combustion catalyst body is heated and the heat-exchanged hot exhaust gas stream is discharged as hot air. On the other hand, the second
The combustion catalyst reaches its activation temperature due to the flow of hot exhaust gas from the first combustion catalyst, at which point the second combustion catalyst is also supplied with fuel gas, and the second combustion catalyst reaches its activation temperature. Catalytic combustion is also initiated on the medium. At this time, in the entire catalytic burner, the hot exhaust gas flow from the first combustion catalyst is discharged as warm air, and at the same time, far-infrared radiation is obtained from the second combustion catalyst. Therefore, warm air with excellent heating ability and comfortable radiation can be obtained at the same time. In addition, the combustion gas discharged from the first combustion catalyst body and the second combustion catalyst body is
Clean exhaust gas with low NOx1 and low C○, which is unique to catalytic combustion, can be obtained.

Embodiments Hereinafter, embodiments of the present invention will be described based on the accompanying drawings.

In FIG. 1, there is a mixing device 5 formed by a mixing fan 2 and a fuel nozzle 4 extending from a first electromagnetic valve 3 at the bottom of a refracted cylindrical combustion tube 1 made of heat-resistant metal.
There is a rectifying partition wall 6 toward the downstream side from the mixing device 5, and further downstream there is a flashback prevention plate 7 made of a heat-resistant ceramic porous plate, and at the tip of the combustion tube 1 further downstream there is a honeycomb-shaped heat-resistant porous ceramic plate. A first combustion catalyst body 9 supporting an oxide of a transition metal such as Ni, Co, or Fe as a first oxidation catalyst 8 is installed. In front of the first combustion catalyst body 9 is a burner case 10 made of heat-resistant metal, and at the bottom of the burner case 10 is a fuel dispersion pipe 12 extending from a second electromagnetic valve 11 made of heat-resistant ceramic fiber. A heat-resistant porous ceramic fiber aggregate containing platinum group metals such as Pt, Pci, and Ph is placed in front of the fuel diffusion material 13 as a second oxidation catalyst 14. Second combustion catalyst body 1 supporting one or more types
5 is held by a holding net 16. Furthermore, a protective net 17 for protecting the front surface of the second combustion catalyst body 15 is installed in front of the holding net 16. The combustion tube 1, the mixing device 5, and the burner case 10 are housed in an outer case 19 having an air intake port 18 at the rear. In front of the air intake port 18, there is an upper louver 20 that determines the flow path of the incoming air, and in the lower part of the combustion tube 1, there is a hot exhaust gas flow from the first combustion catalyst body 9 and a flow path of the air from the air intake port 18. Lower louver 2 that determines the flow path of the air mixture with the incoming air
There is a blower 22 in the lower louver 21 for inducing the above-mentioned mixed air flow, and at the outlet of the lower louver 21 there are multiple wind direction louvers 23 for controlling the blowing direction of the above-mentioned mixed air flow. is set up. Furthermore, a spark plug 24 is installed just before the first combustion catalyst body 9 so as to penetrate through the upper louver 20 .

Next, the operation of the above configuration will be explained.

When the mixing fan 2 rotates due to energization, combustion air is taken into the mixing device 5, and at the same time, the first electromagnetic valve 3 opens and fuel gas flows into the mixing device 5 from the fuel nozzle 4.

The fuel gas and combustion air that are uniformly stirred in the mixing device 5 become a fuel premix, pass through the rectifying partition wall 6 to be rectified, and then pass through the flashback prevention plate 7 to be used for the first combustion. Catalyst body 9
The spark plug 24, which is already generating a spark, ignites the spark. After ignition, the flame formed on the front surface of the first combustion catalyst body 9 gradually spreads inside the first combustion catalyst body 9, but as it spreads, the flame gradually disappears.
The process moves to high-temperature catalytic combustion of about 900 to 1100°C. On the other hand, the energization of the spark plug 24 is stopped after ignition is confirmed. Further, at the same time as the ignition, the blower 22 is also energized, and the hot exhaust gas flow discharged from the first combustion catalyst 9 mixes with the air flowing in from the air intake port 18 while heating the entire burner case 10. The hot air is drawn along the lower louver 21 by the wind direction louver 2a, and is discharged diagonally upward as warm air. In this state, when the second combustion catalyst 15 reaches the activation temperature by receiving heat from the first combustion catalyst 9, the second electromagnetic valve 11 opens, and the fuel diffusion material 13
Fuel gas is supplied through the fuel distribution pipe 12 facing inside. The supplied fuel gas, while uniformly diffusing through the fuel diffusion material 13, reaches the second combustion catalyst body 15, which has already reached the activation temperature, and catalytic combustion starts at about 400°C to 500°C. As the catalytic combustion extends throughout the second combustion catalyst body 15, far-infrared rays begin to be radiated from the front surface of the second combustion catalyst body 15.

In this way, when each catalytic combustion in the first combustion catalyst body 9 and the second combustion catalyst body 15 reaches a stable state, immediate warming due to hot air and comfort due to far-infrared radiation are improved. You get both. Further, when the room in which the catalyst burner of the embodiment is installed is heated to a certain temperature, the first combustion catalyst body 9
It is also possible to stop the catalytic combustion and stop the hot air, and perform mild heating using only far-infrared radiation from the second combustion catalyst 15. Furthermore, the combustion gas discharged from both the first combustion catalyst body 9 and the second combustion catalyst body 15 is clean with low NOx and low CO, which is characteristic of catalytic combustion, and in particular, the NOx value is low. In the exhaust gas from the combustion catalyst body 15 of No. 2, there is almost no NOx, @1
Among the exhaust gases from the combustion catalyst body 9, the total NOx value is less than 5 ppm, and the NO2 content is almost non-existent, resulting in extremely clean exhaust gases.
When used as a heating device, there is almost no problem of indoor air pollution.

Effects of the Invention According to the catalytic burner of the present invention, the following effects can be obtained.

(1) Two combustion catalyst bodies are provided, a second combustion catalyst housed in a burner case made of heat-resistant metal is installed in front of the first combustion catalyst body, and a second combustion catalyst body is installed in front of the first combustion catalyst body. The hot exhaust gas stream discharged from the combustion chamber can be used to preheat the second combustion catalyst body and at the same time can be used as hot air.

(■ With the above configuration, it is possible to utilize both or one of the far-infrared radiation emitted from the second combustion catalyst and the warm air emitted from the first combustion catalyst.

(3) With the above configuration, it is possible to obtain clean exhaust gas with low NOx and low Co, which is characteristic of catalytic combustion.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of an embodiment of a catalytic burner according to the present invention, and FIG. 2 is a longitudinal sectional view of a conventional example. 1... Combustion tube, 5... Mixing device, 8.
...First oxidation catalyst, 9...First combustion catalyst body, 10...Burner case, 14...
...Second oxidation catalyst, 15...Second combustion catalyst body, 22...Blower. Name of agent: Patent attorney Toshio Nakao and 1 other person/-
--W-filled droplet 6-straightening partition wall 2z2/ Fig. 2

Claims (4)

[Claims] (1) A honeycomb-shaped first combustion catalyst body that is made of heat-resistant porous ceramics and supports a first oxidation catalyst at the tip of a combustion tube that has a mixing device for fuel gas and combustion air at the rear. A burner case made of heat-resistant metal and having a fuel gas inlet at the bottom is installed in front of the first combustion catalyst, and a heat-resistant porous ceramic fiber aggregate is placed inside the burner case. A catalytic burner including a second combustion catalyst supporting an oxidation catalyst and a blower for discharging exhaust gas from the first combustion catalyst as warm air. (2) As the material of the first combustion catalyst body, Al_2O_
3. Cordierite, mullite, mullite-zircon,
A catalytic burner according to claim 1, using one of resistant ceramics such as zirconia. (3) Claim 1 or 2 in which a transition metal oxide or a mixture of the transition metal oxide and a rare earth element oxide is used as the first oxidation catalyst.
The catalytic burner described in section. (4) The catalytic burner according to claim 1 or 2, wherein a platinum group metal or a platinum group metal mixed with a transition metal oxide is used as the second oxidation catalyst.