JP3860262B2 - Catalytic combustion device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a catalytic combustion apparatus for burning gaseous fuel or liquid fuel.
[0002]
[Prior art]
A conventional catalytic combustion apparatus will be described with reference to FIG. The gas tank 1 stores liquefied fuel gas such as propane and butane. The fuel gas in the gas tank 1 is ejected from the gas nozzle 3 through the gas flow path 2. The fuel gas ejected from the gas nozzle 3 sucks the surrounding air by the gas flow attracting action, is uniformly mixed in the mixing chamber 4, and is supplied to the combustion chamber 5. The combustion chamber 5 has a catalyst body 6 inside, and burns the mixed gas on the surface of the catalyst body 6 to generate combustion heat.
[0003]
An ignition device 7 is provided on the opposite side of the gas mixture inlet of the combustion chamber 5, and the mixed gas is ignited by blowing a spark from the plug 8 at the tip of the ignition device 7. When the catalyst body 6 is heated by the flame formed downstream of the catalyst body 6 and the temperature of the catalyst body 6 reaches the activation temperature, catalytic combustion starts on the surface of the catalyst body 6 and no mixed gas is supplied to the flame. Disappear.
[0004]
Thereafter, the mixed gas supplied into the combustion chamber 5 performs catalytic combustion in the entire catalyst body 6 in the combustion chamber 5, and the combustion gas is discharged from the exhaust port 9 to the atmosphere.
[0005]
[Problems to be solved by the invention]
However, such a conventional catalytic combustion apparatus has the following problems.
[0006]
In order to completely burn the fuel in contact with the surface of the catalyst, the catalyst temperature must be maintained at a temperature higher than the specific activation temperature. For this reason, a system is employed in which the catalyst is heated by a flame at the start, the catalyst temperature is raised to the activation temperature or higher, fuel is supplied to the catalyst, and catalytic combustion is started.
[0007]
However, in practice, there is a time lag between when the catalyst temperature reaches the activation temperature, the mixed gas is not supplied to the flame, the flame disappears, and the catalyst combustion starts in the entire catalyst and the catalyst is red hot. However, there is a problem that this time lag is long.
[0008]
Accordingly, the present invention has an object to provide a catalytic combustion apparatus with a short red heat start time in consideration of the problems of the conventional catalytic combustion apparatus as described above.
[0009]
[Means for Solving the Problems]
In order to solve this problem, the present invention according to claim 1 is a gas nozzle that ejects a fuel gas, a mixing unit that mixes the fuel gas ejected from the gas nozzle and air into a mixed gas, and combusts the mixed gas. A combustion chamber having a main catalyst body inside, an ignition device that forms a flame in the downstream portion of the main catalyst body by igniting a mixed gas in the combustion chamber, and an exhaust port provided downstream of the ignition device ; It said main catalyst body and disposed between the exhaust port, the catalytic combustion apparatus being characterized in that a heat capacity is small auxiliary catalytic body than the main catalyst with a base of metal wire.
[0010]
The main catalyst body wall surface and the auxiliary catalyst body based on the metal wire may be thermally connected.
[0011]
Further, the main catalyst body has a communication hole inside, and a heat conductor is inserted so as to close all or part of the communication hole of the main catalyst body, and the main catalyst body wall surface, the heat conductor and the metal wire are made into a base. The auxiliary catalyst body may be thermally connected.
[0012]
And a flame extinguishing net provided between the exhaust port and the combustion chamber, and an auxiliary catalyst body based on a metal wire provided between the main catalyst body and the flame extinguishing net. And may be configured to be thermally connected .
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention and embodiments related to the present invention will be described below with reference to the drawings.
[0014]
The fuel gas is supplied from the gas nozzle 13 to the mixing chamber 14, and the air and fuel gas attracted by the fuel gas jet output are mixed in the mixing chamber 14, and the mixed gas is supplied to the combustion chamber 15. An ignition device 17 is provided on the side of the combustion chamber 15 opposite to the air-fuel mixture inlet, and the gas mixture is ignited by blowing a spark from the plug 18 at the tip of the ignition device 17 at the time of start-up. An attached flame 19 is formed.
[0015]
Further, combustion heat is transmitted from the flame 19 base to the main catalyst body 16, and the main catalyst body 16 is heated. When the temperature of the main catalyst body 16 reaches the activation temperature, catalytic combustion starts from the downstream portion of the main catalyst body 16, the mixed gas is not supplied to the flame 19, and the flame 19 disappears. Thereafter, the catalytic combustion spreads toward the upstream portion of the main catalyst body 16, and eventually the entire main catalyst body 16 undergoes catalytic combustion, and the main catalyst body 16 becomes red hot. The combustion gas burned in the combustion chamber 15 is discharged from the exhaust port 20 to the atmosphere.
[0016]
In the conventional catalytic combustion apparatus, the means for heating the main catalyst body 16 at the time of starting is only the flame 19 formed in the downstream portion of the main catalyst body 16. For this reason, it cannot be said that the main catalyst body 16 is sufficiently heated, and the time lag from when the flame 19 disappears until the main catalyst body 16 becomes red hot may be long.
[0017]
However, in the present invention, the auxiliary catalyst body 21 is provided between the main catalyst body 16 and the exhaust port 20 provided in the combustion chamber 15. For this purpose, the flame 19 formed in the downstream portion of the main catalyst body 16 heats the main catalyst body 16 by supplying heat from the base of the flame 19, as well as high-temperature combustion gas generated by flame combustion. Or the auxiliary catalyst body 21 is also directly heated by the flame tip. Here, since the auxiliary catalyst body 21 is a catalyst based on a metal wire such as expanded metal, the heat capacity is very small compared to the main catalyst body 16, so that the main catalyst body 16 reaches the activation temperature. When the flame formed in the downstream portion of the main catalyst body 16 disappears, red heat has already started.
[0018]
In general, it is known that radiation efficiency is high in catalytic combustion. Therefore, the catalyst itself has a property of absorbing radiant heat very well. For this reason, the radiant heat radiated from the red-heated auxiliary catalyst body 21 is absorbed very well by the main catalyst body 16 and greatly contributes to the temperature increase of the main catalyst body 16. Conventionally, the temperature rise of the main catalyst body 16 after the extinction of the flame 19 was only the heat of reaction due to the catalytic combustion of the main catalyst body itself, whereas in the present invention, as explained above, the main catalyst body itself Since the radiant heat from the auxiliary catalyst body 21 is added in addition to the reaction heat due to the catalytic combustion, the temperature rise rate of the main catalyst body 16 is remarkably increased, and the main catalyst body 16 becomes red hot after the flame 19 is extinguished. Time lag can be shortened.
[0019]
Further, as shown in FIG. 2, the wall surface of the main catalyst body 16 and the auxiliary catalyst body 21 may be thermally connected. 2A is a side view, and FIG. 2B is a front view. With such a configuration, when the main catalyst body 16 is heated, in addition to the radiant heat from the auxiliary catalyst body 21, combustion heat in the auxiliary catalyst body 21 is supplied to the main catalyst body 16 by direct heat conduction from the auxiliary catalyst body 21. Therefore, the time lag until red hot is further reduced.
[0020]
In FIG. 2, the shape of the auxiliary catalyst body 21 is convex, but the same effect can be obtained in a cylindrical shape or a flat plate shape.
[0021]
Further, as shown in FIG. 3, the main catalyst body 16 has a communication hole inside, and a heat conductor 22 is inserted so as to close part or all of the communication hole, so that the wall surface of the main catalyst body 16 and the auxiliary contact The medium 21 and the heat conductor 22 may be configured to be thermally connected. With such a configuration, the heating by direct heat conduction from the auxiliary catalyst body 21 is performed not only from the wall surface of the main catalyst body 16 but also from the inside of the main catalyst body 16, thereby further reducing the time lag until red hot. be able to.
[0022]
When the mixed gas is ignited by the ignition device 17, the flame may propagate to the downstream side of the combustion chamber 15. In order to prevent this, in general, in the catalytic combustor, as shown in FIG. 4, a fire extinguishing net 23 made of a metal mesh, a punting metal, or the like is provided in the vicinity of the exhaust port 20. When the propagated flame passes through the extinguishing net 23, the flame is extinguished because the heat is taken away by the extinguishing net 23. On the other hand, if an ignition mistake occurs and the catalyst is not heated at the time of start-up and the fuel combustion is not started even if the fuel gas is supplied to the catalyst, if a flame such as a lighter is brought close to the exhaust port 20, A flame may adhere to the flame extinguishing net 22 provided in the vicinity of the mouth.
[0023]
However, in the present embodiment, an auxiliary catalyst body 24 based on a metal wire is provided between the main catalyst body 16 and the flame extinguishing net 23, and the flame extinguishing net 23 and the auxiliary catalyst body 24 are thermally connected. It is configured. When the flame 25 adheres to the extinguishing net 23, heat is transmitted from the base of the flame 25 through the extinguishing net 23 to the auxiliary catalyst body 24, the auxiliary catalyst body 24 reaches the activation temperature, and the auxiliary catalyst body 24 starts catalytic combustion. When the auxiliary catalyst body 24 starts catalytic combustion, the mixed gas is not supplied to the flame 25, and the flame 25 disappears. On the other hand, radiant heat is radiated from the auxiliary catalyst body 24 performing catalytic combustion, and this radiant heat heats the main catalyst body 16. For this reason, the temperature of the main catalyst body 16 rises, reaches the activation temperature, and the main catalyst body 16 starts catalytic combustion. Therefore, by providing the auxiliary catalyst body 24, even if a flame adheres to the extinguishing net 23, the flame is extinguished, and the effect that the main catalyst body 16 can normally start catalytic combustion is also added.
(Embodiment 2)
A catalytic combustion apparatus according to an embodiment of the invention related to the present invention will be described with reference to FIG. The gas tank 31 stores liquefied fuel gas such as propane and butane. The fuel gas in the gas tank 31 is ejected from the gas nozzle 33 through the gas flow path 32. A gas flow rate adjusting valve (not shown) may be provided between the gas tank 31 and the gas nozzle 33 so that the flow rate of the fuel gas supplied from the gas tank 31 can be controlled. The fuel gas ejected from the gas nozzle 33 sucks in the surrounding air by the gas flow attracting action, is uniformly mixed in the mixing chamber 34, and is supplied to the combustion chamber 35. The combustion chamber 35 has a main catalyst body 36 inside, and burns the mixed gas on the surface of the main catalyst body 36 to generate combustion heat. As the catalyst supported on the main catalyst body 36, platinum group metals and metal oxides such as nickel, cobalt, iron, manganese, and chromium are used. Particularly preferred are platinum group metals such as platinum, palladium, and rhodium.
[0024]
The fuel gas is supplied from the gas nozzle 33 to the mixing chamber 34, the air attracted by the fuel gas jet output and the fuel gas are mixed in the mixing chamber 34, and the mixed gas is supplied to the combustion chamber 35. An ignition device 37 is provided on the opposite side of the mixture gas inlet of the combustion chamber 35, and the mixed gas is ignited by blowing a spark from the plug 38 at the tip of the ignition device 37, and a flame attached to the downstream portion of the main catalyst body 36. 39 is formed. Combustion heat is supplied to the main catalyst body 36 from the flame 39 base, and the main catalyst body 16 is heated. When the temperature of the main catalyst body 36 reaches the activation temperature, catalytic combustion starts from the downstream portion of the main catalyst body 36, the mixed gas is not supplied to the flame 39, and the flame 39 disappears. Thereafter, the catalytic combustion spreads toward the upstream portion of the main catalyst body 36, and eventually the catalytic combustion is carried out in the entire main catalyst body 36, and the main catalyst body 36 becomes red hot. The combustion gas burned in the combustion chamber 35 is discharged from the exhaust port 40 to the atmosphere.
[0025]
In the conventional catalytic combustion apparatus, the main catalyst body 36 is heated from the flame 39 formed in the downstream part of the main catalyst body 36 at the time of starting. On the other hand, the stability of the flame is affected by the state in which the flame base is attached to the flame opening. Therefore, when catalytic combustion starts at the flame base and the mixed gas is not stably supplied to the flame base, the flame 39 formed in the downstream portion of the main catalyst body 36 floats up from the main catalyst body, and the flame 39 disappears. To do. For this reason, it cannot be said that the main catalyst body 36 is sufficiently heated, and the time lag from when the flame 39 disappears until the main catalyst body 36 becomes red hot may be long.
[0026]
However, in the invention related to the present invention , the unsupported layer 41 on which the catalyst is not supported is provided downstream of the main catalyst body 36. With such a configuration, the flame 39 formed in the downstream portion of the main catalyst body 36 at the time of start-up does not carry a catalyst on the flame base portion, so that the main catalyst body 36 is compared with the conventional catalytic combustion apparatus. The stability of the flame 39 formed in the downstream portion is improved, and the time until the flame disappears becomes longer. For this reason, the main catalyst body 36 is sufficiently heated, and the time lag from when the flame 39 disappears until the main catalyst body 36 becomes red hot can be shortened.
[0027]
【The invention's effect】
As is apparent from the above description, according to the present invention, a catalytic combustion apparatus having a short red heat start time can be provided.
[Brief description of the drawings]
FIG. 1 is a vertical sectional view of a catalytic combustion apparatus according to a first embodiment of the present invention. FIG. 2 is a configuration diagram of a catalyst body according to the first embodiment of the present invention. FIG. 4 is a vertical sectional view of another example of the catalytic combustion apparatus according to the first embodiment of the present invention. FIG. 5 is an embodiment of the invention related to the present invention. Fig. 6 is a vertical sectional view of a conventional catalytic combustion apparatus. Fig. 6 is a vertical sectional view of a conventional catalytic combustion apparatus.
13, 33 Gas nozzle 14, 34 Mixing chamber 15, 35 Combustion chamber 16, 36 Main catalyst body 20, 40 Exhaust port 21, 24 Auxiliary catalyst body 22 Thermal conductor 23 Flame extinguishing net 41 Unsupported layer

Claims (5)

A gas nozzle for ejecting fuel gas;
A mixing unit that mixes the fuel gas ejected from the gas nozzle and air into a mixed gas;
A combustion chamber for combusting the mixed gas and having a main catalyst body therein;
An ignition device that forms a flame in the downstream portion of the main catalyst body by igniting the mixed gas in the combustion chamber;
An exhaust port provided downstream of the ignition device ;
An auxiliary catalyst body provided between the main catalyst body and the exhaust port, having a metal wire as a base and having a smaller heat capacity than the main catalyst body ;
Catalytic combustion apparatus comprising the. 2. The catalytic combustion apparatus according to claim 1, wherein the auxiliary catalyst body reaches a red hot temperature before the flame is extinguished and raises the temperature of the main catalyst body by radiant heat. 3. The main catalyst body wall and the metal wire of the auxiliary catalyst to the substrate, the catalytic combustion apparatus according to claim 1 or 2, characterized in that it is thermally connected. The main catalyst body has a communication hole therein, and a heat conductor is inserted so as to close all or part of the communication hole of the main catalyst body, and the wall surface of the main catalyst body, the heat conductor, and the The catalytic combustion apparatus according to any one of claims 1 to 3, wherein an auxiliary catalyst body having a metal wire as a base is thermally connected. Flameproof net is provided between the combustion chamber and the exhaust port, said auxiliary catalyst is, the main catalyst and the disposed between the flameproof net, said auxiliary catalyst and the thermal and the flameproof net The catalytic combustion apparatus according to any one of claims 1 to 4, wherein the catalytic combustion apparatus is connected to.

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