JPH1151333A - Catalytic combustion equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide catalytic combustion equipment utilizing radiation from the surface of catalysis body effectively, enabling high heat exchanging efficiency and having an excellent exhaust gas characteristic. SOLUTION: Catalytic combustion equipment is provided with a catalysis body 7 comprising multiple through holes combusting the mixed gas of fuel gas and air, combustion chamber 6 accommodating the catalysis body 7 and the part of which side walls are radiation heat receiving plates 11 arranged facing the upstream surface 7a of the catalysis body 7, and a copper tube 12 fixed with multiple fins 13 arranged to the outlet of the combustion chamber 6. Nearly all of the radiation from the downstream surface of the catalysis body 7 is radiated to the fins 13 and the copper tube 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a catalyst for gaseous or liquid fuel, and uses the generated heat and exhaust gas to perform heating, heating, drying, etc., with good exhaust gas characteristics. The present invention relates to a catalytic combustion device.

[0002]

2. Description of the Related Art Conventionally, a catalytic combustion apparatus for performing heating, heating, drying, etc. by catalytically burning gaseous fuel or liquid fuel is shown in FIG.
The configuration shown in FIG.

The conventional catalytic combustion apparatus will be described with reference to FIG. In FIG. 7, fuel gas supplied from a fuel supply valve 1 is mixed with air supplied from an air supply valve 2 in a premixing chamber 3 and sent to a preheating burner 4 as a premixed gas. Then, it is ignited by the ignition device 5,
A flame is formed in the preheating burner 4. The high-temperature exhaust gas generated by the flame passes through the catalyst 7 provided in the combustion chamber 6 while heating, and is discharged from the exhaust port 8. When the temperature of the catalyst body 7 rises to a level having activity, the supply of fuel is temporarily stopped by the fuel supply valve 1 to extinguish the flame. Immediately thereafter, refueling starts the catalytic combustion. The catalyst body is in a high temperature state and radiates and radiates through a glass 9 provided at a position facing the upstream side of the catalyst body.
Heating and heating were performed by radiating heat as higher-temperature exhaust gas.

[0004]

In this catalytic combustion, since combustion occurs on the surface of the catalyst, a large amount of radiation is emitted from the catalytic body according to the apparent surface area of the catalytic body. On the other hand, in a catalytic combustion device in which heat is exchanged using a heat medium or the like to perform heating or heating, combustion heat generated on the catalyst body must be efficiently exchanged with the heat medium. For that purpose, radiation from the catalyst body surface also needs to be effectively exchanged. However, if the radiant heat from the catalyst body is not transferred to the heat exchanger and heats the other outer wall of the combustor or is radiated outside the combustor,
Accordingly, there has been a problem that the heat exchange efficiency of the catalytic combustion device becomes poor.

In the case of exchanging heat with a heat medium in a combustion chamber having a catalyst, if the surroundings of the catalyst are fixed directly to the combustion chamber and the heat of combustion on the catalyst is exchanged by heat conduction, heat exchange with the combustion chamber may occur. The temperature of the catalyst body decreases around the catalyst body which is the fixed part. If the temperature of the catalyst body decreases, unburned components are discharged because the catalytic activity decreases. Further, if a large amount of unburned components is discharged, a stable combustion state may be disturbed. Therefore, if a configuration is provided such that an interval is provided between the catalyst body and the combustion chamber, and heat exchange is performed by radiant heat transfer, the temperature drop of the catalyst body due to the heat transfer can be reduced,
A stable combustion state can be maintained. However, since the mixed gas flows in the vicinity of the combustion chamber wall, there is a problem that exhaust gas containing unburned components is discharged from the vicinity of the combustion chamber wall.

[0006] Further, most of the combustion is performed in the upstream part of the catalyst body, and the upstream surface of the catalyst body tends to be in a high temperature state, so that there is a problem that the catalyst body exceeds the heat resistance limit depending on the combustion conditions.

Further, when the catalyst is attached to the combustion chamber, the heat of combustion on the catalyst is transferred to the combustion chamber by heat conduction from a portion attached to the combustion chamber. For this reason, there has been a problem that the temperature of the catalyst body near the catalyst body holder decreases, the catalytic activity decreases locally, and exhaust gas containing unburned components is discharged.

An object of the present invention is to provide a catalytic combustion apparatus which effectively utilizes radiation from the surface of a catalyst body and has a high heat exchange efficiency in consideration of such conventional problems.

It is another object of the present invention to provide a catalytic combustion device which ensures a stable combustion state and has good exhaust gas characteristics when a heat exchange is performed in a combustion chamber containing a catalyst body. .

Another object of the present invention is to provide a catalytic combustion apparatus capable of suppressing a temperature rise on an upstream surface of a catalyst body so that an upstream portion of the catalyst body does not exceed a heat resistance limit.

It is another object of the present invention to provide a catalytic combustion apparatus which prevents unburned components from being discharged from a portion where a catalytic body is attached to a combustion chamber, and has excellent exhaust gas characteristics.

[0012]

According to a first aspect of the present invention, there is provided a catalyst having a plurality of communicating holes for burning a mixed gas of fuel and air, and a housing for accommodating the catalyst and a flow of the mixed gas of the catalyst. A combustion chamber having a radiation heat receiving plate installed facing the upstream side surface in the direction, a first heat medium passage provided in the radiation heat receiving plate, and a number of fins provided downstream in the flow direction of the catalyst body. The catalytic combustion device includes a second heat medium flow path and an exhaust path provided between the fins, and the plurality of fins are disposed at positions facing at least both ends of the catalyst body.

In this configuration, for example, by shortening the interval at which the fins are provided or by increasing the length in the flow direction, radiation from the downstream surface of the catalyst to the fins and the second heat medium flow path is performed. Irradiate almost all of them.

According to a fourth aspect of the present invention, there is provided a premixing chamber for mixing fuel and air to produce a mixed gas, a catalyst body having a plurality of holes for burning the mixed gas, and communicating with the premixing chamber. A combustion chamber for storing a medium, wherein all or a part of the side surface of the catalyst body is exposed in the combustion chamber so as to receive radiant heat from the inner wall of the combustion chamber facing the side surface, and the mixed gas is Is a catalytic combustion device provided with a closed portion in the combustion chamber so that exhaust gas cannot pass through a gap between a side surface of the combustion chamber and an inner wall of the combustion chamber.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings showing an embodiment.

FIG. 1 is a configuration diagram of a catalytic combustion device according to a first embodiment of the present invention. That is, this catalytic combustion device has a fuel supply valve 1 for controlling a fuel gas supply amount and an air supply valve 2 for controlling an air supply amount.
Is connected to Downstream of the premixing chamber 3 is a preheating burner 4 which leads to a combustion chamber 6. In the combustion chamber 6, a catalyst body 7 using a ceramic honeycomb having a large number of communication holes as a carrier is provided.
A radiant heat receiving plate 11 provided with a radiant absorption layer 10 is provided in close contact with a copper tube 9 serving as a first heat medium flow passage through which water flows, at a position facing the upstream surface 7a of the catalyst body 7. I have. Further, at the outlet of the combustion chamber 6, a copper tube 12 of a second heat medium flow path which is fixed with a number of fins 13 and is connected to the copper tube 9 is provided. The outlet of the combustion chamber 6 is connected to an exhaust port 8. Also, the fins 13
The fins 13 are provided on the copper tube 9 in a state where fins 13 are provided at narrow intervals and the exhaust path 14 is formed.

In the above configuration, the fuel gas supplied from the fuel supply valve 1 and the air supplied from the air supply valve 2 are mixed in the premixing chamber 3 and supplied to the preheating burner 4. At this time, water is supplied to the copper tubes 9 and 12.
By the ignition of the ignition device 5 near the preheating burner 4, a flame is formed in the preheating burner 4, and the temperature of the catalyst body 7 is increased by high-temperature exhaust gas generated from the flame. When the temperature of the catalyst 7 becomes active, the supply of the fuel gas is temporarily stopped by the fuel supply valve 1 to extinguish the flame. Immediately thereafter, the fuel gas is supplied from the fuel supply valve 1 to start catalytic combustion in the catalyst body 7. The high-temperature exhaust gas discharged from the catalyst body 7 is discharged from the exhaust port 8 through the exhaust path 14.

At the time of steady combustion, the upstream surface 7a of the catalyst 7
The temperature is from 00 ° C to 850 ° C, and the downstream surface is from 600 ° C to 750 ° C. Here, since the fins 13 are arranged at narrow intervals, most of the radiation from the downstream surface of the catalyst body 7 is directly applied to the fins 13 or the copper tube 12. Here, since the fin 13 is generally made of copper, the radiation coefficient is 0.2 to 0.3. Therefore, a part of the radiation is transferred to the fins 13 and the copper tube 12 to exchange heat with water, but a part of the radiation is reflected on the surfaces of the fins 13 and the copper tube 12 and irradiated to the downstream surface of the catalyst 7. When the downstream surface of the catalyst body 7 is irradiated, heat conduction to the downstream side in the catalyst body 7 is suppressed, so that the temperature of the entire catalyst body 7 rises. Accordingly, the temperature of the high-temperature surface 7a of the catalyst 7 is further increased, and the temperature of the upstream
A lot of radiation occurs from At a position facing the catalyst body upstream surface 7a, there is a radiation heat receiving plate 11 provided with a radiation absorbing layer 10 on the inner surface and a copper tube 9 adhered thereto.
Radiation from the upstream surface 7a is transferred to the radiation heat receiving plate 11 and exchanges heat with water. That is, radiation reflected by the fins 13 and the copper tube 12 also exchanges heat with water. The high-temperature exhaust gas generated by the heat of combustion on the catalyst body 7 transfers heat to the fins 13 and the copper tube 12 by heat transfer when passing through the exhaust path 14 to exchange heat with water. Therefore, heat can be exchanged without almost radiating radiation from the surface of the catalyst body 7 to the outside of the catalytic combustion device, so that a catalytic combustion device with high heat exchange efficiency can be realized.

It should be noted that the fins 13 may be long in the flow direction so that almost all radiation from the downstream surface of the catalyst body 7 is irradiated to the copper tubes and fins.

In the first embodiment, the fins 13 are provided in a direction perpendicular to the surface of the catalyst body 7.
For example, as shown in FIG.
May be installed obliquely to the surface of the catalyst body 7. Alternatively, all the fins may be installed obliquely in the same direction.

FIG. 2 is a block diagram of a catalytic combustion device according to a second embodiment of the present invention. In the present embodiment, the first
The fin 13 and the copper tube 1 are further added to the configuration of the embodiment.
2 is provided with a radiation absorbing layer 15.

In the present embodiment, the radiation applied to the fins 13 and the copper tubes 12 from the downstream surface of the catalyst 7 is efficiently absorbed by the radiation absorbing layer 15 and exchanges heat with water.
Therefore, almost all the radiation from the downstream surface of the catalyst body 7 is absorbed by the fins 13 and the copper tube 12 and can exchange heat, so that a catalytic combustion device with high heat exchange efficiency can be realized.

As the radiation absorbing layer 15, a black paint having a high radiation coefficient may be thinly applied to the surfaces of the fins 13 and the copper tube 12, or the surface state may be roughened by blasting or the like to increase the radiation coefficient. Is also good.

FIG. 3 is a configuration diagram of a catalytic combustion device according to a third embodiment of the present invention. That is, this catalytic combustion is performed by a fuel supply valve 1 for controlling a fuel gas supply amount,
An air supply valve 2 for controlling the amount of air supply is provided and connected to the premixing chamber 3. Downstream of the premixing chamber 3 is a catalyst body 17 having a number of holes. A combustion chamber 16 is provided so as to surround the catalyst body 17, and the combustion chamber 16 continues to the exhaust port 8. A gap is provided between the flow direction side wall of the catalyst body 17 and the inner wall of the combustion chamber 16, and a flow stopper 19, which is a closing portion of the flow path, is provided in this gap. A preheating burner (not shown) having an ignition device is provided upstream of the catalyst body 17, and a copper tube 18 through which water as a heat medium flows is provided in close contact with the outside of the combustion chamber 16.

In the above configuration, the fuel gas supplied from the fuel supply valve 1 and the air supplied from the air supply valve 2 are mixed in a premixing chamber 3 and supplied to a preheating burner (not shown). A flame is formed in the preheating burner by an ignition device (omitted in the drawing), and the temperature of the catalyst 17 is increased by high-temperature exhaust gas generated from the flame. When the temperature of the catalyst 17 becomes active, the supply of the fuel gas is temporarily stopped by the fuel supply valve 1 to extinguish the flame. Immediately thereafter, the catalyst body 17 starts catalytic combustion by supplying the fuel gas through the fuel supply valve 1. The combustion heat generated on the catalyst body 17 is radiated from the exhaust port 8 as high-temperature exhaust gas of the catalyst body 17, and at the same time, is radiated and transferred from the outer peripheral portion of the catalyst body 17 to the inner surface of the combustion chamber 16. Closely attached copper tube 1
Heat exchange with the water in 8.

Since the catalyst 17 is positioned at a position where a gap is provided between the catalyst 17 and the inner surface of the combustion chamber 16, the combustion heat generated on the catalyst 17 is transferred from the outer periphery of the catalyst 17 to the combustion chamber 16 by radiant heat transfer. Heat is transferred to the inner surface. In the case of heat transfer by heat conduction, heat is transferred by the temperature gradient in the solid, so that the temperature decreases on the catalyst body near the heat exchange section. However, since the heat transfer by radiation is conducted in a non-contact state, the temperature of the catalyst body can be maintained at a high state. Therefore, a stable temperature state of the catalyst can be maintained. Further, since the mixed gas flows only inside the high-temperature catalyst body 17 by the flow stopper 19, the mixed gas almost burns. Therefore, with this configuration, heat exchange can be performed in a stable combustion state, and a catalytic combustion device with good exhaust gas characteristics can be realized.

FIG. 4 is a block diagram of a catalytic combustion device according to a fourth embodiment of the present invention. That is, this catalytic combustion device has a fuel supply valve 1 for controlling a fuel gas supply amount and an air supply valve 2 for controlling an air supply amount.
Is connected to Downstream of the premixing chamber 3 is a preheating burner (omitted in the figure), which continues to the combustion chamber 16. Combustion chamber 1
A catalyst body 17 having a large number of communication holes is provided in 6, and a copper pipe 18 through which water as a heat medium flows is provided in close contact with the outside of the combustion chamber 16. An exhaust port 8 is provided downstream of the combustion chamber 16. The catalyst body 17 is attached to the combustion chamber 16 at an upstream portion of the catalyst body 17 by the holder 20, and at the same time, the mixed gas does not flow into the gap between the side surface of the catalyst body 17 and the inner surface of the combustion chamber 16.

In the above configuration, the fuel gas supplied from the fuel supply valve 1 and the air supplied from the air supply valve 2 are mixed in the premixing chamber 3 and supplied to a preheating burner (not shown). A flame is formed in the preheating burner 4 by an ignition device (omitted in the figure) near the preheating burner, and the temperature of the catalyst body 17 is increased by high-temperature exhaust gas generated from the flame. When the temperature of the catalyst 17 becomes active, the supply of the fuel gas is temporarily stopped by the fuel supply valve 1 to extinguish the flame. Immediately thereafter, the catalyst body 17 starts catalytic combustion by supplying the fuel gas through the fuel supply valve 1. The combustion heat generated on the catalyst body 17 is radiated from the exhaust port 8 as high-temperature exhaust gas of the catalyst body 17, and at the same time, is radiated and transferred from the outer peripheral portion of the catalyst body 17 to the inner wall of the combustion chamber 16. The heat is exchanged with the water in the copper tube 18 in close contact.

Most of the combustion in the catalyst 17 is performed upstream of the catalyst 17 to which the mixed gas is supplied. Therefore, the upstream portion of the catalyst body 17 may be in a high temperature state and exceed the heat resistance limit of the catalyst. However, in the present embodiment, since the holder 20 is connected to the upstream portion of the catalyst body 17 and is attached to the combustion chamber 16, the catalyst body 1 is thermally conductive.
The heat of combustion in the upstream portion of 7 is transferred to the combustion chamber 16. Therefore, the temperature of the upstream part of the catalyst body 17 can be reduced, and can be lower than the heat resistance limit. Further, since the mixed gas does not flow through the gap between the side surface of the catalyst body 17 and the combustion chamber 16 but flows through the place surrounded by the catalyst body 17 due to the holder 20, heat exchange can be performed in a stable combustion state by radiant heat transfer. As a result, combustion with good exhaust gas characteristics can be performed. Therefore, it is possible to prevent the upstream surface of the catalyst body 17 from exceeding the heat-resistant limit temperature, and to realize a catalytic combustion device having good exhaust gas characteristics.

FIG. 5 is a block diagram of a catalytic combustion apparatus according to a fifth embodiment of the present invention. That is, this catalytic combustion device has a fuel supply valve 1 for controlling a fuel gas supply amount and an air supply valve 2 for controlling an air supply amount.
Is connected to Downstream of the premixing chamber 3 is a preheating burner (omitted in the figure), which continues to the combustion chamber 16. Combustion chamber 1
A catalyst body 17 having a large number of communication holes is provided in 6, and a copper pipe 18 through which water as a heat medium flows is provided in close contact with the outside of the combustion chamber 16. An exhaust port 8 is provided downstream of the combustion chamber 16. The catalyst body 17 is attached to the combustion chamber 16 at the downstream portion of the catalyst body 17 by the holder 21, and at the same time, the mixed gas does not flow into the gap between the side surface of the catalyst body 17 and the inner surface of the combustion chamber 16.

In the above configuration, the fuel gas supplied from the fuel supply valve 1 and the air supplied from the air supply valve 2 are mixed in the premixing chamber 3 and supplied to a preheating burner (not shown). A flame is formed in the preheating burner 4 by an ignition device (omitted in the figure) near the preheating burner, and the temperature of the catalyst body 17 is increased by high-temperature exhaust gas generated from the flame. When the temperature of the catalyst 17 becomes active, the supply of the fuel gas is temporarily stopped by the fuel supply valve 1 to extinguish the flame. Immediately thereafter, the catalyst body 17 starts catalytic combustion by supplying the fuel gas through the fuel supply valve 1. The combustion heat generated on the catalyst body 17 is radiated from the exhaust port 8 as high-temperature exhaust gas of the catalyst body 17, and at the same time, is radiated and transferred from the outer peripheral portion of the catalyst body 17 to the inner wall of the combustion chamber 16. The heat is exchanged with the water in the copper tube 18 in close contact.

Here, in the holder 21 in which the catalyst body 17 is attached to the combustion chamber 16, the heat of combustion of the catalyst body 17 is transferred to the combustion chamber 16 by heat conduction, and the temperature of the catalyst body 17 is locally reduced. . If the temperature of the catalyst decreases, the catalytic activity decreases, and the mixed gas cannot be completely burned and is discharged from the downstream portion of the catalyst 17 as exhaust gas containing unburned components. However, in this configuration, since the holder 21 is attached to the downstream portion of the catalyst 17, the temperature drop occurs in the downstream of the catalyst 17. Here, the catalytic combustion is performed by the catalyst 17.
Almost completely unburned components do not exist in the downstream portion of the catalyst body 17 because the reaction is almost completed in the upstream portion of the catalyst body 17. Therefore,
Even if the temperature of the downstream portion of the catalyst body 17 is reduced by the holder 21, the exhaust gas characteristics are not affected. In addition, since the mixed gas does not flow between the catalyst body 17 and the combustion chamber 16 due to the holder 21, the mixed gas passes only through the inside of the catalyst body 17 having good catalytic activity, so that almost complete combustion can be performed. . Therefore, it is possible to realize a catalytic combustion device having very good exhaust gas characteristics.

In each of the above embodiments, the temperature of the catalyst body at the time of startup is increased by forming a flame in the preheating burner. However, an electric heater such as a ceramic heater is provided in the upstream and downstream parts of the catalyst body. It is also possible to provide a method in which the catalyst body is provided and heated.

In any of the above embodiments, a ceramic honeycomb body having a large number of communication holes may be used as a carrier of the catalyst body, or a catalyst having a large number of communication holes formed of a high heat-resistant metal sheet. May be formed and used.

[0035]

As is apparent from the above description, according to the present invention, it is possible to increase the heat exchange efficiency by irradiating almost all of the radiation from the catalyst surface to the fin and the heat medium flow path, which are the heat exchange section. Has advantages.

According to the present invention, if a gap is provided between the side surface of the catalyst body and the inner wall of the combustion chamber, and a closing portion is provided in the gap, heat exchange can be performed in a stable combustion state, and the exhaust gas characteristics can be improved. Is good.

According to the present invention, if a gap is provided between the side surface of the catalyst body and the inner wall of the combustion chamber, and the upstream portion of the catalyst body is used as a portion for attaching the catalyst body to the combustion chamber, the upstream portion of the catalyst body is heat resistant. Exceeding the limit is prevented and the combustion characteristics are improved.

Further, according to the present invention, if a gap is provided between the side surface of the catalyst body and the inner wall of the combustion chamber, and the downstream portion of the catalyst body is used as a portion for attaching the catalyst body to the combustion chamber, the catalyst body mounting portion can be provided. Unburned components are prevented from being discharged due to a decrease in the catalyst temperature, and the exhaust gas characteristics become very good.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a catalytic combustion device according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram of a catalytic combustion device according to a second embodiment of the present invention.

FIG. 3 is a configuration diagram of a catalytic combustion device according to a third embodiment of the present invention.

FIG. 4 is a configuration diagram of a catalytic combustion device according to a fourth embodiment of the present invention.

FIG. 5 is a configuration diagram of a catalytic combustion device according to a fifth embodiment of the present invention.

FIG. 6 is a view showing another example of the fin attachment state in the catalytic combustion device of the first embodiment.

FIG. 7 is a configuration diagram of a conventional catalytic combustion device.

[Explanation of symbols]

 6, 16 Combustion chamber 7, 17 Catalyst 9, 12, 18 Copper tube 10, 15 Radiation absorption layer 11 Radiation heat receiving plate 13 Fin 14 Exhaust path 19 Flow stop 20, 21 Holder

Continued on the front page (72) Inventor Yoshitaka Kawasaki 1006 Kadoma Kadoma, Osaka Pref.Matsushita Electric Industrial Co., Ltd. Motohiro Suzuki 1006 Kazuma Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (6)

[Claims] 1. A catalyst body having a large number of communication holes for burning a mixed gas of fuel and air, the catalyst body is housed, and the catalyst body is installed to face an upstream side surface of the catalyst body in a flow direction of the mixed gas. Combustion medium having a radiation heat receiving plate, a first heat medium flow path provided in the radiation heat receiving plate, and a second heat medium flow path provided downstream of the catalyst body in the flow direction of the catalyst body and having a large number of fins. And an exhaust path provided between the fins, wherein the plurality of fins are arranged at positions facing at least both ends of the catalyst body. 2. The catalytic combustion apparatus according to claim 1, wherein fins are installed obliquely with respect to the surface of the catalyst body. 3. The catalytic combustion device according to claim 1, wherein a radiation absorbing layer is provided on a surface of the second heat medium flow path and the fins. 4. A premixing chamber for mixing fuel and air to produce a mixed gas, a catalyst body having a plurality of holes for burning the mixed gas, and communicating with the premixing chamber to house the catalyst body. The catalyst body is exposed in the combustion chamber so that all or a part of the side surface of the catalyst body receives radiant heat from the inner wall of the combustion chamber facing the side surface, and the mixed gas is exposed to the contact gas. A catalytic combustion device, wherein a closing portion is provided in the combustion chamber so as to prevent exhaust from passing through a gap between a side surface of a medium and an inner wall of the combustion chamber. 5. The catalytic combustion device according to claim 4, wherein the closing portion is a holder provided at an upstream end or a downstream end of the catalyst body and connected to the combustion chamber. . 6. The catalytic combustion apparatus according to claim 4, wherein a heat medium flow path is closely attached to or incorporated in a part or all of the combustion chamber.