JPH0933007A - Combustion device - Google Patents

Abstract

(57) Abstract: In a combustion device having a problem that the temperature of the catalyst body is 1200 ° C. or more and the heat resistant life of the catalyst is remarkably shortened, the problem that the heat resistant life of the catalyst is remarkably shortened can be solved. An object of the present invention is to provide a combustion device using the. SOLUTION: A mixing portion 3 that mixes fuel and combustion air to generate a mixture, a first catalyst body 7 that catalytically burns the mixture, and the mixture is catalytically burned by the first catalyst body 7. A first catalytic combustion chamber 4 that houses a fin 5 that collects thermal energy generated when the first catalytic body 7 and a second catalytic body 14 that catalytically burns the air-fuel mixture that has not been catalytically burned by the first catalytic body 7. A combustion device that includes a two-catalyst combustion chamber 12, the first catalyst body 7 is mounted substantially along the fins 5, and the surface area 14 of the second catalyst body is larger than the surface area of the first catalyst body 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heater, a water heater, an air conditioner, a portable heat device, etc., which burns a gaseous fuel such as natural gas or propane gas or a liquid fuel such as kerosene or light oil as a heat source. The present invention relates to a combustion device used.

[0002]

2. Description of the Related Art Catalytic combustion is a method of burning a mixture of fuel and air using a catalyst body in which a platinum group metal catalyst is supported on a ceramic carrier such as a honeycomb or a fiber.

A combustion catalyst has a selective adsorption property for oxygen and hydrocarbons, and both react on the surface of the catalyst. At this time, the temperature of the catalyst is lower than that of the flammable combustion of the same gas, so that NOx is hardly generated.

The flammable combustion range is an excess air ratio of 1 to 2. On the other hand, the flammable range of catalytic combustion is
The excess air ratio is in the range of 1 to 5, and combustion can be performed using a lean air-fuel mixture.

[0005]

However, when a combustion device using a catalyst is operated at the same combustion load rate (combustion amount per volume of the combustion chamber) as that of the flammable combustion device, the temperature of the catalyst body becomes 1200 ° C. or higher. There arises a problem that the heat resistant life of the catalyst is significantly shortened. For this reason, the catalyst must be used below the heat-resistant limit temperature, the combustion load is reduced to increase the size, or the excess air ratio in the mixture of fuel and air is increased to lower the combustion temperature. Is required.

Further, when the air-fuel mixture is made lean, there arises a problem that thermal efficiency is greatly reduced. That is, since the combustion temperature decreases as the fuel concentration decreases, the temperature difference between the heat exchanger and the combustion exhaust decreases, and the heat transfer rate decreases. Therefore,
A large heat exchanger is required to increase the thermal efficiency, and it is difficult to configure a catalytic combustion device having a large combustion capacity with a small device.

Further, in catalytic combustion, air and fuel must be mixed and reacted in advance, but when the fuel is a liquid fuel, there is a problem that the heat for vaporizing the fuel becomes large. In a conventional vaporization type liquid fuel combustion device using flame combustion, the vaporizer is heated by an electric heater only at the start of combustion, but at the time of steady combustion, the flame is applied to a part of the vaporizer to heat the vaporizer. Consumption is low. However, in the conventional combustion device using catalytic combustion, since there is no flame, it is necessary to supply electricity for vaporization heat even in a steady state, and there is a problem that extra power consumption is required.

An object of the present invention is to provide a combustion apparatus in which NOx is hardly generated in consideration of the above problems of the conventional combustion apparatus.

It is another object of the present invention to provide a combustion device using a catalyst which can solve the problem that the heat resistance life of the catalyst is extremely shortened.

It is another object of the present invention to provide a combustion device using a catalyst that can be downsized.

Another object of the present invention is to provide a combustion device using a catalyst which has a large combustion capacity even if it is small in size, without the need to increase the excess air ratio in the mixture of fuel and air.

Another object of the present invention is to provide a combustion device which does not generate unpleasant odors because it does not emit unburned gas at the start of combustion.

Still another object of the present invention is to provide a combustion apparatus which does not need to supply electricity for heat of vaporization even in a steady state.

[0014]

In order to solve this problem, the present invention according to claim 1 provides a mixture generating section for mixing a fuel and combustion air to generate a mixture, and the mixture. A first catalyst body located on the downstream side in the flow direction of the above for catalytically burning the air-fuel mixture, and a first heat recovery unit for collecting thermal energy generated when the air-fuel mixture is catalytically burned by the first catalyst body; And a second catalyst that is located on the exhaust side of the first catalyst body and that houses the second catalyst body that catalytically burns the air-fuel mixture that has not been catalytically burned by the first catalyst body. A combustion chamber, the first catalyst body is mounted substantially along the first heat recovery part, and the surface area of the second catalyst body is larger than the surface area of the first catalyst body. It is a combustion device.

The first heat recovery section is a fin,
All or part of the first catalyst body may be attached to the fin along the fin with a predetermined gap.

Further, the fin may have a plurality of surfaces for collecting the thermal energy, and the predetermined gap may be narrower than a gap between each surface of the fin and a surface adjacent thereto.

Further, the first catalyst body may be a metal carrier supporting a catalyst on all or part thereof, and the second catalyst body may be a ceramic carrier supporting a catalyst on all or part thereof.

The amount of combustion in the first catalytic combustion chamber may be larger than the amount of combustion in the second catalytic combustion chamber.

Further, the combustion apparatus further comprises a first heat extraction section attached to the outer surface of the first catalyst combustion chamber for extracting the heat energy collected by the first heat recovery section to the outside. You may. In addition, the first
The heat extraction unit may use water or air as a medium for extracting the thermal energy to the outside.

Further, the combustion apparatus further includes a second heat recovery section located on the exhaust side of the second catalytic combustion chamber for collecting thermal energy contained in the exhaust gas discharged from the second catalytic body, and a second heat recovery section thereof. A second heat extraction unit may be provided which is attached to the outer surface of the chamber in which the second heat recovery unit is housed and which extracts the heat energy collected by the second heat recovery unit to the outside. The second heat recovery unit is a fin,
The second heat extraction unit may use water or air as a medium for extracting the thermal energy to the outside.

Further, the combustion apparatus may further include a first flame combustion chamber accommodating a first ignition means between the air-fuel mixture producing section and the first catalyst combustion chamber. The combustion device further prevents the flame generated in the first flame combustion chamber from spreading between the mixture generation section and the first flame combustion chamber to the mixture generation section. The first flame holding unit may be provided. Further, the combustion device is further provided between the first flame combustion chamber and the second catalyst combustion chamber, and is provided in an inner peripheral portion of the first catalyst combustion chamber over a flow direction of the air-fuel mixture. The bypass may be provided, and an opening / closing means for opening / closing an entrance of the bypass located between the first flame combustion chamber and the first catalytic combustion chamber may be provided. Furthermore, the combustion apparatus further includes a heat recovery unit that returns a part of heat generated in the first flame combustion chamber to the mixture generation unit between the mixture generation unit and the first flame combustion chamber. May be provided. Further, the heat conductivity of the metal material forming the heat recovery unit may be lower than the heat conductivity of the metal material forming the air-fuel mixture generating unit. Furthermore, a thermal resistance part may be provided at a connection part between the mixture generation part and the heat recovery part. Further, the heat recovery unit may be provided with a passage hole for the air-fuel mixture. Further, after the supply of the air-fuel mixture is started, the air-fuel mixture is ignited by the first ignition means to form a flame in the first flame combustion chamber,
After the temperature on the upstream side of the catalyst body reaches a predetermined value by the flame, the flame may be extinguished by temporarily stopping the supply of the air-fuel mixture, and the supply may be restarted after the flame disappears. .

Further, the combustion apparatus may further include a first heating chamber for accommodating a first heating means between the air-fuel mixture generating section and the first catalytic combustion chamber. In addition,
The combustion device further includes a first flame holding element for preventing a flame generated in the first heating chamber from spreading to the air-fuel mixture generating section between the air-fuel mixture generating section and the first heating chamber. It may be provided with a section. Further, the combustion device is further provided between the first heating chamber and the second catalytic combustion chamber, and is provided in an inner peripheral portion of the first catalytic combustion chamber over a flow direction of the air-fuel mixture. The bypass may be provided, and an opening / closing means for opening / closing an inlet of the bypass located between the first heating chamber and the first catalytic combustion chamber may be provided. Further, the first heating means is filled with a heater wire, a metal-coated tube housing the heater wire, and the metal-coated tube,
An insulating material for insulating the heater wire from the metal-coated tube, and a heat dissipation plate having a plurality of holes and having a heat radiation material formed on the surface thereof, wherein the metal-coated tube is the heat dissipation plate. May be joined to. Further, the heat dissipation plate may be formed in a box shape, and the metal-coated tube may be bonded to a bottom surface of the heat dissipation plate. Further, the combustion device further includes a heat recovery unit between the air-fuel mixture generation unit and the first heating chamber that returns a part of heat generated in the first heating chamber to the air-fuel mixture generation unit. You may. Further, the heat conductivity of the metal material forming the heat recovery unit may be lower than the heat conductivity of the metal material forming the air-fuel mixture generating unit.
Further, a heat resistance part may be provided at a connection part between the air-fuel mixture generation part and the heat recovery part. Further, the heat recovery section may be provided with a passage hole for the air-fuel mixture.

Further, the combustion apparatus may further include a second flame combustion chamber accommodating a second ignition means between the first catalyst combustion chamber and the second catalyst combustion chamber. .
The combustion device further prevents the flame generated in the second flame combustion chamber from spreading toward the first catalyst combustion chamber between the first catalyst combustion chamber and the second flame combustion chamber. A second flame holding portion for performing the above may be provided. Further, the second heating means is filled in the heater wire, the metal-coated tube housing the heater wire, and the metal-coated tube to insulate the heater wire from the metal-coated tube. An insulating material and a heat dissipation plate having a plurality of holes and having a heat radiation material formed on the surface may be provided, and the metal-clad pipe may be bonded to the heat dissipation plate. Further, the heat dissipation plate may be formed in a box shape, and the metal-coated tube may be bonded to the bottom surface of the heat dissipation plate. Further, after the supply of the air-fuel mixture is started, the air-fuel mixture is ignited by the second igniting means to form a flame in the second flame combustion chamber,
After the temperatures of the downstream side of the catalyst body and the upstream side of the second catalyst body reach a predetermined value due to the flame, the flame is extinguished by temporarily stopping the supply of the air-fuel mixture, and after the flame disappears. The supply may be restarted.

Further, the combustion apparatus may further include a second heating chamber accommodating a second heating means between the first catalytic combustion chamber and the second catalytic combustion chamber. The combustion device further prevents the flame generated in the second heating chamber from spreading to the first catalytic combustion chamber between the first catalytic combustion chamber and the second heating chamber. It is also possible to provide a second flame holding part for

According to a twentieth aspect of the present invention, there is provided a vaporization section having a vaporization heater for vaporizing a liquid fuel and mixing the vaporized fuel with combustion air to produce a mixture.
A heat recovery plate provided on the downstream side of the vaporization section, a catalyst combustion chamber provided on the downstream side of the heat recovery plate and containing a catalyst body for catalytically burning the air-fuel mixture, and the vaporization section. A detection unit that detects the internal temperature of the vaporizer, and a power control unit that controls the power of the vaporization heater based on the detected temperature. A catalyst is carried on all or part of the heat recovery plate, In the combustion device, a part of the heat recovery part is thermally conductively connected to the vaporization part.

The present invention will be described below with reference to examples.

As a means for solving the problems of catalyst heat resistance and combustion load factor of catalytic combustion, the present invention provides a first catalytic combustion body having a heat exchange type and a geometric surface area represented by a honeycomb shape. This is a combustion device in which a large second catalytic combustion body is arranged in series. The first catalytic combustion body utilizes the high heat transfer property of catalytic combustion, and is a heat exchange type catalytic combustion in which a catalytic body is provided in a heat receiving fin. Even if a large amount of high-concentration air-fuel mixture is burned by the catalyst body, the combustion heat is removed by heat exchange, so that deterioration of the catalyst body due to high temperature can be prevented. Part of the fuel is burned and the heat of combustion is removed by such a first catalytic combustion body, and the remaining fuel is burned by the second catalytic body provided downstream in the flow direction. Since the temperature of the second catalyst body is equal to or higher than the catalytic reaction temperature, the first catalyst body does not burn the entire amount of fuel, but the first and second catalyst bodies share and burn the fuel.

Therefore, the first catalyst body is a catalyst carrier having a high thermal conductivity at a rough interval, and the second catalyst body is a catalyst carrier having a large geometric surface area, that is, a minute interval.

The operation of the first catalyst body of the present invention obtained by utilizing the high heat transfer property of catalytic combustion will be described below. In a conventional flammable combustion device, hot exhaust gas molecules excite vibrations of metal molecules in a heat exchanger to transfer heat. Molecules that have lost vibrations stay on the metal surface and impede heat transfer, so a heat exchange section with a large surface area is required. On the other hand, in the first catalyst body used in the present invention, the heat exchange portion is directly covered by the catalyst body, so that the fuel gas is adsorbed on the catalyst to generate heat, and the heat directly vibrates the atoms of the catalyst layer, This vibration transfers heat in the form of propagating to the metal atoms forming the heat exchanger. Therefore, even if a large amount of fuel is burned in a small area, the temperature of the catalyst body becomes 900 ° C. or lower due to cooling by heat transfer. Further, since the combustion section and the heat exchange section are integrated, the size can be reduced.

Since a part of the fuel burns in the first catalytic body,
No flame can be formed downstream of this. Therefore, the second catalytic body performs catalytic combustion capable of lean combustion. A honeycomb structured catalyst body having a large surface area is suitable for burning all the remaining unburned gas. The reaction of the honeycomb catalyst body may be performed by a known technique.

As described above, according to the present invention which uses two catalytic bodies having different properties, low NOx property due to low temperature combustion of catalytic combustion and prevention of high temperature of the catalyst when the combustion load is increased, High heat transferability of catalytic combustion in the first catalyst body and miniaturization of the heat exchanger by integration can be realized at the same time.

Next, what is a practical problem in such a basic structure is a reaction initiation method. In order to start catalytic combustion, the temperature of the catalyst must be raised above the activation temperature. If the preheating is insufficient, the amount of unburned gas in the exhaust gas when shifting to catalytic combustion increases. This is a waste of fuel and also causes the problem of combustion odor.

Means for raising the temperature include the heat of an electric heater or flame, which must be used to heat the two types of catalytic combustors simultaneously and in time. First
Since the catalyst body does not burn all the fuel, it is necessary that the second catalyst body is always kept at an activation temperature or higher before the start of catalytic combustion so that unburned gas is not discharged to the exhaust gas.

Therefore, a flame combustion section or an electric heater for preheating the second catalyst body is required between the first catalyst body and the second catalyst body. Even if a preheating means is provided in front of the first catalyst body,
This is because the high-temperature hot air does not heat the second catalyst body because it is cooled because the first catalyst body has the heat exchange section.

In order to increase the combustion rapidly,
It is necessary to add preheating means to the first catalyst body as well as the second catalyst body. This is because if combustion is started in a state where the first catalyst body does not react, the amount of fuel that reacts in the second catalyst body increases until the first catalyst body reaches a steady temperature, so that the high temperature deterioration of the second catalyst body occurs. . Depending on the combination of these preheating means, the steady combustion arrival time, power consumption, initial exhaust gas characteristics, equipment cost, etc. are changed. Characteristic combustion start is possible by selection according to each application.

Further, in order to reduce the power consumption for vaporization when liquid fuel is used, it is effective to provide a heat recovery section carrying a catalyst integrated with the vaporization section upstream in the flow direction of the first catalyst body. is there.

[0037]

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

The combustion apparatus according to the first embodiment of the present invention will be described with reference to FIG. 1 which is a sectional view thereof. Reference numeral 1 is a fuel supply unit that supplies a fuel gas. Two
Is a blower that supplies combustion air. A mixing unit 3 mixes the fuel gas supplied by the fuel supply unit 1 and the combustion air supplied by the blower 2 to form a mixture. The mixing unit 3 houses a mixing plate 21.

Reference numeral 4 denotes a first portion provided on the downstream side of the mixing section 3.
It is a catalytic combustion chamber. Reference numeral 5 is a heat receiving fin that projects to the inner surface of the first catalytic combustion chamber 4. The length of the fin 5 in the flow direction is 100 mm, the thickness of each part thereof is 3 mm, and the height thereof is 30 mm. Reference numeral 7 is a thin plate-shaped first catalyst body provided in the fin 5 with a gap 6 therebetween. The first catalyst body 7 is composed of a thin plate heat-resistant iron alloy as a substrate, and coated on both surfaces thereof with a catalyst layer made of γ-alumina carrying a platinum group metal catalyst such as platinum or palladium.
Reference numeral 8 is a first water passage for heat exchange provided on the outer periphery of the first catalytic combustion chamber 4 made of an aluminum alloy. The inside of the first catalytic combustion chamber 4 and the first water passage 8 are also shown in FIG. 2, which is a cross-sectional view taken along the line AA ′ of FIG. 1.

Reference numeral 9 is a flame combustion chamber provided on the downstream side of the first catalytic combustion chamber 4. Reference numeral 11 is an ignition means such as a high pressure discharge or a high temperature heater housed in the flame combustion chamber 9.

Reference numeral 10 denotes the first catalytic combustion chamber 4 and the flame combustion chamber 9.
It is a flame retention part made of wire mesh and punching metal provided on the border with.

Reference numeral 12 is a second catalytic combustion chamber provided on the downstream side of the flame combustion chamber 9. 13 is the flame combustion chamber 9 and the second
It is a heat insulating material attached to the inner peripheral surface of the catalytic combustion chamber 12. Reference numeral 14 is a second catalyst body having a honeycomb structure of 300 cells / inch square having a larger geometric surface area than the first catalyst body 7 housed in the second catalyst combustion chamber 12. Second catalyst body 14
The thickness in the flow direction is 20 mm. The honeycomb carrier of the second catalyst body 14 is a ceramic porous body such as cordierite or lime aluminate, and carries a platinum group metal catalyst. The honeycomb hole is a square having a side of 0.6 mm square.

Reference numeral 15 is a fin for heat exchange, which is provided on the downstream side of the second catalytic combustion chamber 12 for recovering exhaust heat. 1
6 is a second water passage for heat exchange provided on the outer peripheral surface of the chamber accommodating the fins 15. The second water path 16 is the first
It is connected to the water channel 8. The heated water is used for heating and hot water supply. The fins 15 and the second water paths 16 are also shown in FIG. 3, which is a sectional view taken along the line BB ′ of FIG. 1.

Air cooling may be used instead of the first water passage 8 and the second water passage 16. In this case, warm air is generated.

Next, the function of the combustion apparatus of the present invention will be described.

The air-fuel mixture sent from the mixing section 3 is fed to the fins 5.
And the first catalytic combustion chamber 4 accommodating the first catalytic body 7. The excess air ratio of the air-fuel mixture may be between 1 and 2 in the flammable range, but is preferably between 1.1 and 1.6. This is because if the excess air ratio is 1.1 or less, an air deficient portion occurs and incomplete combustion occurs, and if it is 1.6 or more, ignition becomes difficult.

The air-fuel mixture becomes a flame by the ignition means 11 of the flame combustion chamber 9. As a result, combustion starts. The second catalyst body 14 is heated by the heat of the flame and reaches the activation temperature of 300 ° C. The activation temperature differs depending on the type of fuel or catalyst. For example, the activation temperature of propane gas is about 300 ° C., methane is higher than this, and kerosene is lower than this. If flame combustion continues in this state,
The temperature of the second catalyst body 14 reaches 400 to 600 ° C. When the temperature of the first catalyst body 7 is heated to 300 ° C. by the radiant heat of the upstream surface of the second catalyst body 14 and the flame holding portion 10,
The catalytic combustion reaction starts from the downstream side in the flow direction of the first catalyst body 7. As the temperature of the first catalyst body 7 rises due to the reaction, the reaction position goes upstream in the upstream direction of the first catalyst body 7.

When the amount of the air-fuel mixture burned in the first catalytic combustion chamber 4 increases, 75% of the supplied fuel is burned in the first catalytic combustion chamber 4. The second catalytic combustion chamber 12 burns the rest. The fuel concentration of the air-fuel mixture in the flame combustion chamber 9 becomes thin because the exhaust gas is mixed, and the flame disappears. First catalyst body 7
, A flameless combustion reaction occurs on the surface of the catalyst that adsorbs fuel gas and oxygen. The heat of the first catalyst body 7 is transmitted as radiant heat to the fins 5 through the gaps 6.

Although the first catalyst body 7 and the fins 5 may partially contact each other, it is preferable to provide a gap 6 between the first catalyst body 7 and the fins 5. This is because the temperature of the fins 5 is 100 to 300 ° C. due to the cooling of the first water path 8, and if the first catalyst body 7 is in contact with the fins 5, the catalyst is cooled and the temperature of the fins 5 is reduced. This is because the temperature of the first catalyst body 7 becomes lower than the activation temperature.

Therefore, if there is a gap 6 between the first catalyst body 7 and the fins 5, the propagation of heat from the first catalyst body 7 to the fins 5 is carried out by radiant heat, so that the first catalyst body 7 is formed. When the temperature is high, the radiant heat increases in proportion to the fourth power of the temperature, so that the effect of suppressing the temperature rise of the first catalyst body 7 itself is produced, and it is possible to saturate the catalyst body at a temperature lower than the heat resistant temperature of the catalyst body. Becomes If the temperature of the first catalyst body 7 becomes low, the temperature of
Since the radiant heat decreases in proportion to the power, the effect of suppressing the temperature decrease of the first catalyst body 7 itself is produced, and stable combustion is possible.

Next, the combustion efficiency of the present combustion device will be described based on the experimental results. The air-fuel mixture burned in the first catalytic combustion chamber 4 was 75% of the air-fuel mixture sent from the mixing unit 3. In addition, the air-fuel mixture burned by the first catalyst body 7 of the first catalytic combustion chamber 4 is converted into radiant heat as the first catalytic combustion chamber 4
Heat is transferred to the first water path 8 from the fins 5 housed in. The energy transferred from the fins 5 to the first water passage 8 is 80% of the energy generated by the combustion in the first catalytic combustion chamber 4.
Met. Therefore, 60% of the fuel supplied to this combustion device
% (= 75 × 80%) is heat exchanged between the first catalytic combustion chamber 4 and the first water passage 8.

The exhaust gas discharged from the first catalytic combustion chamber 4 contains the remaining air-fuel mixture which is not burned in the first catalytic combustion chamber 4 (hereinafter referred to as unburned fuel). That is, 25% (= 100% -75%) of the fuel supplied to this combustion device
However, it becomes the unburned fuel.

On the other hand, all the remaining 15% (= 75% -60%) of the radiant heat that has not been transferred from the fins 5 to the first water passage 8 is a flame from the first catalytic combustion chamber 4 as exhaust heat. Assuming that the exhaust gas is discharged to the second catalytic combustion chamber 12 via the combustion chamber 9, the total exhaust gas discharged from the first catalytic combustion chamber 4 is 40% (= 25%) of the fuel supplied to the present combustion device. % +
15%) equivalent energy will be included.

Here, if the temperature of the second catalyst body 14 decreases, the unburned fuel becomes difficult to react, so that the efficiency of heat exchange becomes poor, or heat exchange is not performed. Therefore, in order to deal with this problem, the heat insulating material 13 is
It is attached to the inner peripheral surfaces of the flame combustion chamber 9 and the second catalytic combustion chamber 12. The second catalyst body 14 has a honeycomb structure having a larger geometric surface area than the first catalyst body 7 in order to efficiently catalytically burn unburned fuel. As a result, the unburned fuel is efficiently burned in the second catalytic combustion chamber 12.

The exhaust heat discharged from the second catalytic combustion chamber 12 is transferred from the fins 15 to the second water passage 16 of the fins 15. In the experiment, the heat exchange rate of the exhaust heat by the fins 15 is 70.
%Met. Therefore, assuming that the second catalytic body 14 has burned all unburned fuel, the exhaust heat discharged from the second catalytic combustion chamber 12 is 40% of that of the fuel supplied to the present combustion device.
% Of energy will be included. In this case, the second
The heat recovered by the water path 16 is 28% (= 40% × 7
0%).

After all, the total thermal efficiency of the present combustion apparatus, which is evaluated based on the experimental results, is the first water path 8 and the second water path 16
88% (60%) of the total heat energy recovered by
% + 28%).

The combustion amount ratio of the first catalyst body and the second catalyst body is not limited to the ratio of this embodiment,
The optimum value varies depending on the application and the size of the device.

As shown in FIG. 2, the gap 6 between the fin 5 and the first catalyst body 7 facing the fin 5 is narrower than the gap 17 between the first catalyst bodies 7 adjacent to each other. You may have it. Furthermore, a catalyst layer may be formed on the back and front surfaces of the first catalyst body 7. This allows the fin 5
It is possible to prevent slipping of unreacted fuel in the vicinity and increase the amount of combustion in the first catalyst body 7. This is because the temperature of the air-fuel mixture in the vicinity of the fins 5 is lower than the temperature of the air-fuel mixture in the interval 17, so that the catalytic reaction is difficult to proceed and the air-fuel mixture is also difficult to diffuse to the catalyst surface.

A combustion device according to a second embodiment of the present invention will be described with reference to FIG. 4 which is a sectional view thereof. Reference numeral 1 is a fuel supply unit for supplying liquid fuel through the fuel pipe 18. A vaporization heater 19 heats the liquid fuel. A blower 2 sends combustion air. Two
Reference numeral 0 is a vaporization unit that houses the mixing plate 21.

Reference numeral 24 is a first flame combustion chamber provided on the downstream side of the vaporizing section 20. Reference numeral 23 is a first ignition means for igniting the air-fuel mixture generated in the vaporization section 20. The first ignition means 23 is housed in the first flame combustion chamber 24. 22
Is a first flame holding part provided between the vaporizing part 20 and the first flame combustion chamber 24.

Reference numeral 4 is a first catalytic combustion chamber provided on the downstream side of the first flame combustion chamber 24. Reference numeral 5 is a heat receiving fin that projects to the inner surface of the first catalytic combustion chamber 4. Reference numeral 7 is a thin plate-shaped first catalyst body provided on the fin 5 through the gap 6. Reference numeral 8 is a first water path for heat recovery provided on the outer periphery of the first catalytic combustion chamber 4 made of an aluminum alloy.

Reference numeral 27 is a second flame combustion chamber provided downstream of the first catalytic combustion chamber 4. Reference numeral 26 is a second ignition means for igniting the air-fuel mixture. The second ignition means 26 is housed in the second flame combustion chamber 27. Reference numeral 25 is a second flame holding portion provided between the first catalytic combustion chamber 4 and the second flame combustion chamber 27.

Reference numeral 12 is a second catalytic combustion chamber provided downstream of the second flame combustion chamber 27. Reference numeral 14 is a second catalyst body having a honeycomb structure. The second catalytic body 14 is housed in the second catalytic combustion chamber 12. Reference numeral 13 is a heat insulating material attached to the inner peripheral surfaces of the flame combustion chamber 27 and the second catalyst combustion chamber 12.

Reference numeral 15 denotes a heat exchange fin provided downstream of the second catalytic combustion chamber 12 for recovering exhaust heat. 1
6 is a second water passage for heat exchange provided on the outer peripheral surface of the chamber accommodating the fins 15. The second water path 16 is the first
It is connected to the water channel 8. The heated water is used for heating and hot water supply.

That is, the difference of the present embodiment from the first embodiment is that the first flame combustion chamber 24 accommodating the first ignition means and the first flame holding portion 22 are further provided. That is, the fuel has become liquid fuel.

Next, the function of this embodiment will be described.

The liquid fuel supplied from the fuel supply unit 1 is
It drops from the tip of the fuel pipe 18 to the vaporization section 20. Since the tip portion of the fuel pipe 18 and the vaporization section 20 are heated by the vaporization heater 19, the liquid fuel is vaporized in the vaporization section 20. The vaporized fuel is mixed with the combustion air sent from the blower 2 by the mixing plate 21 of the vaporization section 20 to create a mixture.

The air-fuel mixture produced in the vaporization section 20 is sent to the second flame combustion chamber 27 via the first flame combustion chamber 24 and the first catalyst combustion chamber 4. The air-fuel mixture sent to the second flame combustion chamber 27 forms a flame by the ignition of the second ignition means 26.

The second catalyst body 14 is heated by the heat of its flame and reaches the activation temperature of 300.degree. Flame combustion continues, and the temperature of the second catalyst body 14 is 400 to 60.
When the temperature reaches 0 ° C, the first ignition means 23 is energized to
A flame is formed in the flame combustion chamber 24 by the air-fuel mixture. At this time, the flame in the second flame combustion chamber 27 disappears.

The temperature of the first catalyst body 7 is the same as that of the first flame combustion chamber 2
The combustion heat of 4 raises the temperature from the upstream side in the flow direction. When the temperature on the upstream side of the first catalyst body 7 reaches 300 to 600 ° C., the fuel supply is stopped for 5 seconds to make the first flame combustion chamber 2
Extinguish the flame of 4.

By the fuel supply after the flame is extinguished,
The air-fuel mixture sent from the vaporization unit 20 starts catalytic combustion from the upstream of the first catalyst body 7 and the upstream of the second catalyst body 14.

Since the temperature drop of the second catalyst body 14 having no cooling mechanism on the outer periphery is small, the high temperature can be maintained even if the fuel concentration is low, and the catalytic combustion proceeds. Second catalyst body 1
The reaction amount of the catalyst in 4 does not become excessive because the air-fuel mixture partially reacts in the first catalyst body 7. For this reason, the flow rate of the air-fuel mixture sent from the vaporization section 20 can be increased. Therefore, the heat generation at the start of combustion can be made larger than that in the first embodiment.

The combustion is finally stable, and the fuel supplied is 8
5% burns in the first catalytic body 7, and the rest burns in the second catalytic body 14. The situation of this steady combustion is the same as that of the first embodiment.

Next, the function of the present combustion device when the liquid fuel supplied from the fuel supply unit 1 is a high boiling point fuel such as kerosene or light oil will be described. In this case, it is difficult to form the flame of the air-fuel mixture sent to the second flame combustion chamber 27 by the ignition of the second ignition means 26. In particular, ignition at low temperatures becomes difficult. Because the air-fuel mixture is the first catalyst body 7
This is because when passing through, it condenses and the concentration decreases.

The operation of the present combustion apparatus for solving this is as follows.

First, by the first ignition means 23, the vaporizing section 2
A flame is formed in the air-fuel mixture sent from 0 to the first flame combustion chamber 24. The first catalyst body 7 is heated by the heat of this flame. The heating temperature is in the range from the dew point of the air-fuel mixture to the catalyst activation temperature. For example, the heating temperature for kerosene is 70 to 250 ° C. When the first catalyst body 7 reaches the heating temperature, the fuel supply is temporarily stopped to extinguish the flame in the first flame combustion chamber 24.

When the flame of the first flame combustion chamber 24 is extinguished, the fuel supply is restarted and the second ignition means 26 ignites the air-fuel mixture sent to the second flame combustion chamber 27. The mixture is
Since no condensation occurs in the first catalytic combustion chamber 4, there is no decrease in concentration and a flame is formed. The second catalyst body 14 is heated by the heat of the flame and reaches the activation temperature.

With the temperature of the second catalyst 14 reaching the activation temperature, the first ignition means 23 is energized to form a flame by the air-fuel mixture sent to the first flame combustion chamber 24. At this time, the flame in the second flame combustion chamber 27 disappears. The first catalyst body 7 is heated from the upstream side by the combustion heat of the first flame combustion chamber 24. When the temperature of the upstream side of the first catalyst body 7 reaches 400 to 600 ° C., the fuel supply is stopped for 5 seconds to extinguish the flame in the first flame combustion chamber 24.

With the fuel supplied again after the flame is extinguished, the air-fuel mixture sent from the vaporization section 20 starts the reaction from the upstream of the first catalytic body 7 and the upstream of the second catalytic body 14,
Heading for steady combustion.

By this operation, the high boiling point liquid fuel can be easily burned. The steady combustion state is the same as in the first embodiment.

A combustion apparatus according to the third embodiment of the present invention will be described with reference to FIG. 5, which is a sectional view thereof. In the present embodiment, the difference from the first embodiment is that a heater chamber 28 containing an electric heater 29 is provided instead of the flame combustion chamber 9 containing the ignition means 11 without the flame holding part 10. It was provided. Other configurations are the same as those in the first embodiment.

Next, the operation of this embodiment will be described. First, the electric heater 29 is energized to heat the upstream side of the second catalyst body 14 and the downstream side of the first catalyst body 7 by its radiant heat and convective heat. In order to heat the first catalyst body 7 and the second catalyst body 14 whose activation temperature is 300 ° C. or higher to their activation temperature, the temperature of the electric heater 29 is preferably 700 ° C. or higher.

When the first catalyst body 7 and the second catalyst body 14 are heated to the activation temperature, the electric heater 29 is de-energized and the mixture section 3 starts to supply the air-fuel mixture.

The air-fuel mixture starts the reaction on the upstream side of the heated second catalyst body 14. The downstream end of the first catalyst body 7 that receives this heat also starts the reaction and becomes high temperature. The reaction position gradually goes upstream in the upstream direction of the first catalyst body 7.

As the amount of the air-fuel mixture catalytically burned in the first catalyst body 7 increases, the fuel concentration of the gas passing through the heater chamber 28 and flowing to the second catalyst body 14 becomes thinner. With the fuel concentration of the gas flowing through the second catalyst body 14 reduced, the fuel supply amount is increased to reach steady combustion. The combustion state that has reached steady combustion is the same as in the first embodiment.

In the present embodiment, since steady combustion is achieved without using flame, NOx is hardly generated. Further, the accuracy of the air-fuel ratio at the time of ignition need not be as precise as that of flame ignition.

If the air-fuel mixture were to ignite due to the high heat of the electric heater 29 in the heater chamber 28, the flame would backfire in the space of the first catalytic combustion chamber 4 to ignite the mixing chamber 3 as well. In this way, when a flame is generated in the mixing chamber 3, the combustion of both the first catalytic combustion chamber 4 and the second catalytic combustion chamber 12 is
The effect of low NOx disappears because catalytic combustion no longer occurs. Therefore, if a flame-holding portion such as a wire mesh or a perforated plate similar to that shown in FIG. 1 is provided between the first catalytic combustion chamber 4 and the heater chamber 28, even if the heater ignites, a backfire is prevented. It becomes possible to do.

A combustion apparatus according to the fourth embodiment of the present invention will be described with reference to FIG. 6 which is a sectional view thereof. 30 is provided on the upstream side of the first catalytic combustion chamber 4,
The first heater chamber accommodates the first electric heater 31. 3
Reference numeral 2 is a second heater chamber that is provided between the first catalytic combustion chamber 4 and the second catalytic combustion chamber 12 and that houses the second electric heater 33. That is, in the present embodiment, the substantial difference from the third embodiment is that the first electric heater 3
That is, the first heater chamber 30 accommodating 1 is provided.

The line AA 'and the line BB' in FIG.
Sectional views corresponding to the lines are shown in FIGS. 2 and 3, respectively.

Next, the operation of this embodiment will be described.

First electric heater 31 and second electric heater 33
Are energized to simultaneously heat the first catalyst body 7 and the second catalyst body 14 to start catalyst preheating. After the temperatures of the first catalyst body 7 and the second catalyst body 14 reach a predetermined activation temperature, the energization of the first electric heater 31 and the second electric heater 32 is stopped, and the supply of fuel is started. It should be noted that either stop or supply may be performed first.

When the air-fuel mixture sent from the mixing section 3 passes through the first catalytic combustion chamber 4, the air-fuel mixture partially reacts upstream and downstream of the first catalytic body 7.

The unreacted fuel that has passed through the first catalyst body 7 begins to react upstream of the second catalyst body 14. Since the temperature of the second catalyst body 14 is high, the unreacted gas reacts there, and the final exhaust gas contains almost no unburned gas.
The preheating temperature of the second catalyst body 14 is preferably higher than that of the first catalyst body 7 in order to prevent the unburned gas from being discharged from the combustion device to the outside.

In the present embodiment, the heat generation upstream of the first catalyst body 7 is carried along with the flow of the air-fuel mixture and propagates downstream, so that the first catalyst body 7 can reach the steady temperature in a short time. Therefore, in the present embodiment, the maximum output can be obtained in a shorter time than in the third embodiment.

A combustion apparatus according to the fifth embodiment of the present invention will be described with reference to FIG. 7 which is a sectional view thereof. Reference numeral 1 is a fuel supply unit that supplies liquid fuel from the tip of the fuel pipe 18. A vaporization heater 19 heats the liquid fuel. A blower 2 sends combustion air.
Reference numeral 20 is a vaporization unit that accommodates two mixing plates.

Reference numeral 9 is a flame combustion chamber provided on the downstream side of the vaporizing section 20. Reference numeral 11 is an ignition means for igniting the air-fuel mixture generated by the vaporization unit 20. The ignition means 11 is housed in the flame combustion chamber 9. Reference numeral 10 is a flame holding portion provided between the vaporizing portion 20 and the flame combustion chamber 9.

Reference numeral 4 is a first catalytic combustion chamber provided on the downstream side of the flame combustion chamber 9. Reference numeral 5 is a heat receiving fin that projects to the inner surface of the first catalytic combustion chamber 4. Reference numeral 7 is a thin plate-shaped first catalyst body provided on the fin 5 through the gap 6. 8
Is a first water path for heat recovery provided on the outer periphery of the first catalytic combustion chamber 4 made of aluminum alloy.

28 is a heater chamber provided on the downstream side of the first catalytic combustion chamber 4. Reference numeral 44 is an electric heater housed in the heater chamber 28.

Reference numeral 12 is a second catalytic combustion chamber provided on the downstream side of the heater chamber 28. 14 is a second honeycomb structure
It is a catalyst body. The second catalytic body 14 is the second catalytic combustion chamber 12
It is stored in.

Reference numeral 15 is a heat exchange fin provided downstream of the second catalytic combustion chamber 12 for recovering exhaust heat. 1
6 is a second water passage for heat exchange provided on the outer peripheral surface of the chamber accommodating the fins 15. The second water path 16 is the first
It is connected to the water channel 8.

Next, the operation of this embodiment will be described.

First, the electric heater 44 is energized to heat the second catalyst body 14, and the air-fuel mixture is sent from the vaporization section 20. The air-fuel mixture sent to the flame combustion chamber 9 forms a flame by the ignition means 11. At this time, the second catalyst body 14 is connected to the electric heater 44.
Since it is heated by, the odor and CO at the time of ignition are purified here.

When the first catalyst body 7 reaches the activation temperature by being heated by the heat of the flame in the flame combustion chamber 9, the fuel supply is temporarily stopped to extinguish the flame. When the fuel supply is restarted after the flame is extinguished, catalytic combustion occurs in the first catalytic body 7. At this time, the unburned gas is discharged from the heater chamber 28 to the second catalytic combustion chamber 12 because the temperature of the first catalytic body 7 is not completely raised. The unburned gas discharged into the second catalytic combustion chamber 12 reacts with the second catalytic body 14 heated by the electric heater 44.

Since the temperature of the first catalyst body 7 rises from the upstream side in the flow direction, the fuel supply is increased when the downstream side of the first catalyst body 7 reaches 300 to 600 ° C. If the steady combustion state is reached at this timing, the abnormally high temperature of the second catalyst body 14 due to unburned gas can be completely prevented.

As a result, the combustion is finally stabilized, and 85% of the supplied fuel is burned by the first catalyst body 7, and the rest is the second fuel.
The catalyst body 14 burns. The situation of this steady combustion is the same as that of the first embodiment. Therefore, according to the present embodiment, the combustion can be stabilized in a short time, and the emission of unburned gas at the time of ignition can be reduced.

A combustion apparatus according to the sixth embodiment of the present invention will be described with reference to FIG. 8 which is a sectional view thereof. Reference numeral 1 is a fuel supply unit that supplies liquid fuel from the fuel pipe 18. A vaporization heater 19 heats the liquid fuel. A blower 2 supplies combustion air. Two
Reference numeral 0 is a vaporization unit that mixes the vaporized liquid fuel supplied by the fuel supply unit 1 with the combustion air supplied by the blower 2 to form a mixture.

28 is provided downstream of the vaporizing section 20,
It is a heater chamber that houses the electric heater 44.

Reference numeral 4 denotes a first catalytic combustion chamber provided on the downstream side of the heater chamber 28. Reference numeral 5 is a heat receiving fin that projects to the inner surface of the first catalytic combustion chamber 4. Reference numeral 7 is a thin plate-shaped first catalyst body provided on the fin 5 through the gap 6. 8
Is a first water path for heat recovery provided on the outer periphery of the first catalytic combustion chamber 4 made of aluminum alloy.

Reference numeral 9 is a flame combustion chamber provided on the downstream side of the first catalytic combustion chamber 4. Reference numeral 11 is an ignition means for igniting the air-fuel mixture. The ignition means 11 is housed in the flame combustion chamber 9. Reference numeral 10 is a flame holding portion provided between the first catalyst combustion chamber 4 and the flame combustion chamber 9.

Reference numeral 12 is a second catalytic combustion chamber provided on the downstream side of the flame combustion chamber 9. 14 is a second honeycomb structure
It is a catalyst body. The second catalytic body 14 is the second catalytic combustion chamber 12
It is stored in.

Reference numeral 15 denotes a heat exchange fin provided downstream of the second catalytic combustion chamber 12 for recovering exhaust heat. 1
6 is a second water passage for heat exchange provided on the outer peripheral surface of the chamber accommodating the fins 15. The second water path 16 is the first
It is connected to the water channel 8.

Next, the operation of this embodiment will be described.

First, the electric heater 44 is energized to heat the first catalyst body 7, and the air-fuel mixture is sent to the first catalyst body 7. The temperature of the 1st catalyst body 7 shall be below a catalyst activation temperature. Therefore, since no catalytic reaction occurs in the first catalyst body 7, the air-fuel mixture forms a flame in the flame combustion chamber 9 by the ignition means 11. Second
The catalyst body 14 is heated by this flame. Also, the first
The downstream side of the catalyst body 7 is similarly heated. However, the first
Since the upstream of the catalytic body 7 has already been heated by the electric heater 44, the catalytic combustion reaction rapidly reaches the upstream of the first catalytic body 7.

As a result, the combustion finally stabilizes and enters the same steady state as in the first embodiment. This method is effective for liquid fuel and has a simple structure.

A combustion apparatus according to the seventh embodiment of the present invention will be described with reference to FIG. 9 which is a sectional view thereof. Reference numeral 1 is a fuel supply unit for supplying liquid fuel through the fuel pipe 18. A vaporization heater 19 heats the liquid fuel. A blower 2 sends combustion air. Two
Reference numeral 0 is a vaporization unit that houses the mixing plate 21.

Reference numeral 9 is a flame combustion chamber provided on the downstream side of the vaporizing section 20. Reference numeral 11 is an igniting unit that uses an electric discharge to ignite the air-fuel mixture generated in the vaporization unit 20. The ignition means 11 is housed in the flame combustion chamber 9. Reference numeral 10 is a flame holding portion provided between the vaporizing portion 20 and the flame combustion chamber 9.

Reference numeral 4 is a first catalytic combustion chamber provided on the downstream side of the flame combustion chamber 9. Reference numeral 5 is a heat receiving fin that projects to the inner surface of the first catalytic combustion chamber 4. Reference numeral 7 is a thin plate-shaped first catalyst body provided on the fin 5 through the gap 6. 8
Is a first water path for heat recovery provided on the outer periphery of the first catalytic combustion chamber 4 made of aluminum alloy.

Reference numeral 12 is a second catalytic combustion chamber provided downstream of the first catalytic combustion chamber 4. Reference numeral 14 is a second catalyst body having a honeycomb structure having a larger geometric surface area than the first catalyst body 7. The second catalytic body 14 is housed in the second catalytic combustion chamber 12.

Reference numeral 15 is a heat exchange fin provided downstream of the second catalytic combustion chamber 12 for recovering exhaust heat. 1
6 is a second water passage for heat exchange provided on the outer peripheral surface of the chamber accommodating the fins 15. The second water path 16 is the first
It is connected to the water channel 8.

Reference numeral 34 is a bypass which penetrates the central portion of the first catalytic combustion chamber 4. The bypass 34 has an opening / closing valve 35.
Is provided and is opened and closed via the drive unit 36. here,
The on-off valve 35 is preferably provided on the upstream side of the bypass 34. When the opening / closing valve 35 is provided on the downstream side, the bypass 3
This is because the air-fuel mixture staying in No. 4 is ignited by the heat of the first catalyst body 7.

Next, the operation of this embodiment will be described.

The liquid fuel becomes fuel gas in the vaporizing section 20 heated by the vaporizing heater 19. The fuel gas is mixed with the combustion air sent from the blower 2 by the mixing plate 21 housed in the vaporization section 20 to form an air-fuel mixture. The air-fuel mixture flows into the flame combustion chamber 9 provided on the downstream side in the flow direction. The air-fuel mixture flowing into the flame combustion chamber 9 is ignited by the ignition means 11 to form a flame.

At this time, the inlet of the bypass 34 located on the upstream side in the flow direction of the air-fuel mixture is opened by the opening / closing valve 35. Therefore, the first catalyst body 7 and the second catalyst body 14 are heated by the heat of the flame in the flame combustion chamber 9.

The temperature of the first catalyst body 7 and the second catalyst body 14 is 3
When the temperature reaches 00 to 600 ° C., the fuel supply is temporarily stopped to extinguish the flame in the flame combustion chamber 9. Then, the drive unit 36
Thus, the on-off valve 35 at the entrance of the bypass 34 is closed, and the fuel supply is restarted. At this time, the first catalyst body 7
Since the second catalyst body 14 is heated to the activation temperature or higher, the first catalyst body 7 and the second catalyst body 14 immediately start catalytic combustion and reach a stable state.

As described above, in the present embodiment, the temperature of the first catalyst body 7 and the second catalyst body 14 can be made sufficiently high by the single ignition means 11.

A combustion apparatus according to the eighth embodiment of the present invention will be described with reference to FIG. 10 which is a sectional view thereof. Reference numeral 1 is a fuel supply unit that supplies liquid fuel from the fuel pipe 18. A blower 2 supplies combustion air. Reference numeral 20 is a vaporization unit that mixes the liquid fuel supplied by the fuel supply unit 1 and the combustion air supplied by the blower 2 to form a mixture. The vaporization part 20 is made of aluminum or iron casting. Reference numeral 19 is an electric heater for heating the vaporization section 20.

Reference numeral 30 denotes a first heater chamber, which is provided on the downstream side of the vaporizing section 20, and which accommodates the first electric heater 31. A heat recovery plate 37 is attached between the first heater chamber 30 and the vaporization section 20. The heat recovery plate 37 is provided in the vaporization unit 2
It is fixed to the projecting portion 38 of 0 with a screw 39. A plurality of passage holes 40 are provided on the side surface of the heat recovery plate 37, and a flange portion 41 is provided at the downstream end of the side surface. The heat recovery plate 37 is made of a stainless steel plate and carries a catalyst.

Reference numeral 4 is a first catalytic combustion chamber provided on the downstream side of the first heater chamber 30. Reference numeral 5 is a heat receiving fin that projects to the inner surface of the first catalytic combustion chamber 4. Reference numeral 7 is a thin plate-shaped first catalyst body provided on the fin 5 through the gap 6. Reference numeral 8 is a first water path for heat recovery provided on the outer periphery of the first catalytic combustion chamber 4 made of an aluminum alloy. Here, the surface area of the heat recovery plate 37 is smaller than the surface area of the catalyst of the first catalyst body 7.

Reference numeral 32 is a second heater chamber provided on the downstream side of the first catalytic combustion chamber 4. Reference numeral 33 is an electric heater housed in the second heater chamber 32.

Reference numeral 12 is a second catalytic combustion chamber provided downstream of the second heater chamber 32. Reference numeral 14 is a second catalyst body having a honeycomb structure. The second catalytic body 14 is housed in the second catalytic combustion chamber 12.

Reference numeral 15 is a heat exchange fin provided downstream of the second catalytic combustion chamber 12 for recovering exhaust heat. 1
6 is a second water passage for heat exchange provided on the outer peripheral surface of the chamber accommodating the fins 15. The second water path 16 is the first
It is connected to the water channel 8.

42 is provided on the outer surface of the vaporizing section 20,
It is a detection unit that detects the internal temperature of the vaporization unit 20. 43
The vaporization heater 19 keeps the temperature of the vaporization unit 20 at the boiling point of the liquid fuel or higher based on the detection result of the detection unit 42.
It is an electric input control means for controlling.

Next, the operation of this embodiment will be described.

The vaporization heater 19 and the first electric heater 31 are energized to heat the vaporization section 20, the heat recovery plate 37 and the first catalyst body 7. Liquid fuel, such as kerosene or light oil, is vaporized in
Is supplied to the fuel gas, becomes fuel gas there, and is mixed with the combustion air sent from the blast air to form an air-fuel mixture.

The air-fuel mixture passes through the heat recovery plate 37 and the first catalyst body 7 starts catalytic combustion. At the same time, the catalyst of the heat recovery plate 37 heated by the first electric heater 31 also starts the reaction. The reaction heat is transferred from the protruding portion 38 to the vaporizing section 20 to heat the vaporizing section 20. The heating of the flange portion 41 of the heat recovery plate 37 is promoted by the radiant heat of the first catalyst body 7. When the catalytic reaction proceeds further, the heat recovery plate 37 is heated to 400 to 600 ° C. The heat recovery plate 37 transfers the heat to the vaporization section 20.

By the way, the thermal conductivity of the metal material forming the heat recovery plate 37 is preferably lower than the thermal conductivity of the metal material forming the vaporization section 20. If the heat conductivity is high, the vaporization section 20 takes too much heat to lower the temperature, and the heat recovery plate 37
This is because the reactivity of the catalyst is reduced. For this reason, it is also effective to provide the projecting portion 38 at the connecting portion between the vaporization unit 20 and the heat recovery plate 37, select the contact area, and achieve the optimum conduction of vaporization heat.

Further, in order to increase the reaction amount of the catalyst in the heat recovery plate 37, it is effective to provide the heat recovery plate 37 with the passage hole 40. In this case, the air-fuel mixture is the heat recovery plate 37.
And the reaction amount increases, the thermal resistance of the heat recovery plate 37 increases, the temperature of the tip increases, and the reactivity increases.

In such catalytic combustion, the detection unit 42
However, if it detects that the internal temperature of the vaporization section 20 has been heated to a predetermined temperature, the electric input control means 43 stops the energization of the vaporization heater 19. After this, the electric input control means 43
Repeats ON-OFF of the vaporization heater 19 so as to keep the temperature of the vaporization section 20 at the boiling point or higher. As a result, the power consumption for vaporizing the liquid fuel in catalytic combustion can be reduced.

In the present embodiment, the first catalyst body 7
Although the heat exchange integral type is the same as the first catalyst body 7 in the first embodiment, it may be a honeycomb type catalyst body.

The electric heater 44 used in the fifth and sixth embodiments will be described with reference to FIG. 11, which is a structural diagram thereof. FIG. 11B shows ZZ of FIG. 11A.
It is a cross-sectional view taken along the line '. The electric heater 44 can also be used in embodiments using electric heaters other than the fifth and sixth embodiments. Reference numeral 45 is a metal-coated tube. Reference numeral 46 is a heater element wire housed in the metal-coated tube 45. 47 is
It is a magnesia insulating material housed in a metal-clad tube 45.
The heater wire 46 is insulated from the metal-clad tube by the magnesia insulating material 44.

Reference numeral 48 is a heat radiation plate having a heat radiation material formed on the surface thereof. A large number of through holes 50 are formed in the heat dissipation plate 48. Here, in the flow path of the air-fuel mixture, the electric heater 4
When 4 is provided so as to face the catalyst body, the temperature around the catalyst body easily becomes low. Therefore, if the heat dissipation plate 48 is formed in a box shape having a bottom surface and side surfaces to increase the contact area with air, uniform heating becomes possible.

The metal-coated tube 46 is joined to the heat dissipation plate 48 by a nickel brazing material 49.

If the electric heater 44 faces the first catalyst body 7 or the second catalyst body 14, the catalyst can be preheated.

In general, in order to speed up preheating, the electric energy of the electric heater must be increased. However, in this case, the temperature of the metal-coated tube of the electric heater becomes high, which causes a problem of deterioration of the metal-coated tube.

In the electric heater 44 according to the present embodiment, the metal-coated tube 45 is connected to the heat dissipation plate 48 which has been subjected to a surface treatment that easily radiates heat, so that the heat diffused in the heat dissipation plate 48 is radiated. Dissipates as heat. As a result, the metal-coated tube 45 is less likely to deteriorate. As a result, preheating can be performed quickly, and the preheating time of the catalyst can be shortened.

The passage hole 50 is a hole for passing the air-fuel mixture, but if the arrangement of the holes is near the metal-coated tube 45, the heating capacity can be further enhanced.

Although the heat dissipation plate 48 has a box shape having a bottom surface and side surfaces, it may have a flat plate shape.

[0148]

As is apparent from the above, according to the present invention, it is possible to provide a combustion device in which NOx is hardly generated.

Further, according to the present invention, it is possible to solve the problem that the heat resistant life of the catalyst is significantly shortened.

Further, according to the present invention, it is possible to miniaturize the combustion device using the catalyst.

Further, the combustion apparatus of the present invention does not need to increase the excess air ratio in the air-fuel mixture of fuel and air, and can realize a combustion apparatus using a catalyst having a large combustion capacity even if it is small.

Further, according to the present invention, since unburned gas is not emitted at the start of combustion, no bad odor is generated.

Further, in the present invention, it is not necessary to supply electricity for heat of vaporization even in the steady state.

[Brief description of drawings]

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

FIG. 2 is a sectional view taken along the line AA ′ of FIG.

FIG. 3 is a sectional view taken along line BB ′ of FIG.

FIG. 4 is a cross-sectional view of a combustion device according to a second embodiment of the present invention.

FIG. 5 is a sectional view of a combustion device according to a third embodiment of the present invention.

FIG. 6 is a cross-sectional view of a combustion device according to a fourth embodiment of the present invention.

FIG. 7 is a cross-sectional view of a combustion device according to a fifth embodiment of the present invention.

FIG. 8 is a sectional view of a combustion device according to a sixth embodiment of the present invention.

FIG. 9 is a sectional view of a combustion device according to a seventh embodiment of the present invention.

FIG. 10 is a sectional view of a combustion apparatus according to an eighth embodiment of the present invention.

FIG. 11A is a structural diagram of an electric heater 44 used in the fifth and sixth embodiments, and FIG. 11B is its ZZ ′.
It is sectional drawing of a line.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Fuel supply part 2 ... Blower 3 ... Mixing part 4 ... 1st catalyst combustion chamber 5 ... Fin 6 ... Gap 7 ... 1st catalyst body 8 ... 1st water path 9 ... Flame combustion chamber 10 ... Flame holding part 11 ... Ignition Means 12 ... Second catalyst combustion chamber 13 ... Heat insulating material 14 ... Second catalyst body 15 ... Fins 16 ... Second water path 21 ... Mixing plate

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yutaka Yoshida 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (30)

[Claims] 1. An air-fuel mixture generation unit that mixes fuel and combustion air to generate an air-fuel mixture, and a first catalyst body that is located downstream in the flow direction of the air-fuel mixture and catalytically burns the air-fuel mixture. A first catalytic combustion chamber that houses a first heat recovery unit that collects thermal energy generated when the air-fuel mixture is catalytically burned by the first catalytic body, and is located on the exhaust side of the first catalytic body. A second catalytic combustion of the air-fuel mixture that has not been catalytically burned by the first catalytic body
A second catalytic combustion chamber accommodating a catalytic body, wherein the first catalytic body is mounted substantially along the first heat recovery part, and the surface area of the second catalytic body is the first contact area. A combustion device characterized by being larger than the surface area of the medium. 2. The first heat recovery section is a fin, and all or part of the first catalyst body is attached to the fin along a predetermined gap with a predetermined gap. The combustion apparatus according to claim 1, wherein: 3. The fin has a plurality of surfaces for collecting the thermal energy, and the predetermined gap is narrower than a gap between each face of the fin and a face adjacent thereto. Item 4. The combustion device according to item 4. 4. The first catalyst body is a metal carrier supporting a catalyst on all or part thereof, and the second catalyst body is a ceramic carrier supporting the catalyst on all or part thereof. The combustion device according to claim 1. 5. The combustion apparatus according to claim 1, wherein the combustion amount in the first catalytic combustion chamber is larger than the combustion amount in the second catalytic combustion chamber. 6. The first combustion apparatus further comprises: the first catalytic combustion chamber attached to an outer surface of the first catalytic combustion chamber.
The combustion apparatus according to claim 1, further comprising a first heat extraction unit for extracting the heat energy collected by the heat recovery unit to the outside. 7. The combustion apparatus according to claim 6, wherein the first heat extraction section uses water or air as a medium for extracting the thermal energy to the outside. 8. The second combustion recovery unit is located on the exhaust side of the second catalytic combustion chamber and collects thermal energy contained in the exhaust discharged from the second catalytic body. A second heat extraction part attached to the outer surface of the chamber in which the second heat recovery part is housed, for extracting heat energy collected by the second heat recovery part to the outside. The combustion device according to 1. 9. The second heat recovery section is a fin, and the second heat extraction section uses water or air as a medium for extracting the thermal energy to the outside. Combustion device. 10. The combustion apparatus further comprises a first flame combustion chamber accommodating a first ignition means between the mixture generating section and the first catalyst combustion chamber. The combustion device according to claim 1. 11. The combustion apparatus further prevents the flame generated in the first flame combustion chamber from spreading to the mixture generation section between the mixture generation section and the first flame combustion chamber. The combustion apparatus according to claim 10, further comprising a first flame holding portion for performing the above. 12. The combustion apparatus further comprises a first heating chamber for accommodating first heating means between the air-fuel mixture producing section and the first catalytic combustion chamber. The combustion device according to claim 1. 13. The combustion device further prevents the flame generated in the first heating chamber from spreading to the mixture generation section between the mixture generation section and the first heating chamber. 13. The combustion apparatus according to claim 12, further comprising a first flame holding part. 14. The combustion apparatus further comprises a second flame combustion chamber accommodating a second ignition means between the first catalyst combustion chamber and the second catalyst combustion chamber. The combustion device according to claim 1. 15. The combustion device further comprises: between the first catalytic combustion chamber and the second flame combustion chamber, a flame generated in the second flame combustion chamber is directed toward the first catalytic combustion chamber. 15. The combustion device according to claim 14, further comprising a second flame holding portion for preventing the spread. 16. The combustion apparatus further comprises a second heating chamber accommodating a second heating means between the first catalytic combustion chamber and the second catalytic combustion chamber. The combustion device according to claim 1. 17. The combustion device further includes: between the first catalytic combustion chamber and the second heating chamber, flame generated in the second heating chamber does not spread toward the first catalytic combustion chamber. The combustion apparatus according to claim 16, further comprising a second flame holding portion for performing the above. 18. The combustion device is further located between the first flame combustion chamber and the second catalyst combustion chamber, and is located inside the first catalyst combustion chamber across a flow direction of the air-fuel mixture. 11. A bypass provided in a peripheral portion, and an opening / closing means for opening / closing an inlet of the bypass located between the first flame combustion chamber and the first catalyst combustion chamber are provided. Combustion device. 19. The combustion device is further located between the first heating chamber and the second catalytic combustion chamber,
A bypass provided in the inner peripheral portion of the first catalytic combustion chamber and an inlet of the bypass located between the first heating chamber and the first catalytic combustion chamber are provided across the flow direction of the air-fuel mixture. 13. The combustion apparatus according to claim 12, further comprising opening / closing means for opening / closing. 20. A vaporization section provided with a vaporization heater for vaporizing a liquid fuel and mixing the vaporized fuel with combustion air to produce a mixture, and a vaporization section provided downstream of the vaporization section. A heat recovery plate, a catalyst combustion chamber that is provided on the downstream side of the heat recovery plate, and stores a catalytic body for catalytically burning the air-fuel mixture, and a detection unit that detects the internal temperature of the vaporization unit, A power control means for controlling the power of the vaporization heater based on the detected temperature, a catalyst is carried on all or part of the heat recovery plate, and part of the heat recovery part is the vaporization part. Combustion device characterized in that it is thermally conductively connected to. 21. The first heating means comprises a heater wire, a metal-coated tube housing the heater wire, and the metal-coated tube filled with the heater wire to insulate the heater wire from the metal-coated tube. And a heat dissipation plate having a plurality of holes and having a heat radiation material formed on a surface thereof, wherein the metal-clad pipe is bonded to the heat dissipation plate. Item 12. The combustion device according to Item 12. 22. The second heating means comprises a heater element wire, a metal-coated tube accommodating the heater element wire, and the metal-coated tube is filled with the heater element wire to insulate the heater element wire from the metal-coated tube. And a heat dissipation plate having a plurality of holes and having a heat radiation material formed on a surface thereof, wherein the metal-clad pipe is bonded to the heat dissipation plate. Item 16. The combustion apparatus according to Item 15. 23. The combustion device according to claim 21, wherein the heat dissipation plate is formed in a box shape, and the metal-coated tube is joined to a bottom surface of the heat dissipation plate. 24. The combustion device further returns a part of the heat generated in the first flame combustion chamber to the mixture generation unit between the mixture generation unit and the first flame combustion chamber. The combustion apparatus according to claim 10, further comprising a heat recovery unit. 25. The heat recovery device, wherein the combustion device further returns a part of heat generated in the first heating chamber to the mixture generation unit between the mixture generation unit and the first heating chamber. The combustion device according to claim 12, further comprising a portion. 26. The combustion according to claim 24, wherein the heat conductivity of the metal material forming the heat recovery unit is lower than the heat conductivity of the metal material forming the air-fuel mixture generating unit. apparatus. 27. A thermal resistance portion is provided at a connection portion between the mixture generation portion and the heat recovery portion.
Or the combustion device according to 25. 28. The combustion apparatus according to claim 24, wherein the heat recovery section is provided with a passage hole for the air-fuel mixture. 29. After starting the supply of the air-fuel mixture, the air-fuel mixture is ignited by the first igniting means to form a flame in the first flame combustion chamber, and a temperature of the upstream side of the first catalyst body. 11. After reaching a predetermined value by the flame, the supply of the air-fuel mixture is temporarily stopped to extinguish the flame, and after the flame disappears, the supply is restarted. Combustion device. 30. After the supply of the air-fuel mixture is started, the air-fuel mixture is ignited by the second ignition means to form a flame in the second flame combustion chamber, the downstream side of the first catalyst body and the Extinguishing the flame by temporarily stopping the supply of the mixture after the temperature of the upstream side of the second catalyst reaches a predetermined value due to the flame, and restarting the supply after the flame disappears The combustion device according to claim 14, wherein