JPH06137523A - Catalyst burner - Google Patents

Abstract

PURPOSE:To facilitate manufacture of catalyst in a small volume while increasing an area and to make a surface temperature distribution of the catalyst uniform. CONSTITUTION:A catalyst 21 is formed in a cylindrical shape, a fuel mixture gas supply tube 25 having a plurality of through holes 25a inside is provided, and mixture gas of petroleum vapor and the air is supplied to the catalyst 21 from a vapor injection tube 41 from below the tube 25.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a catalytic combustion device for burning a supplied fuel on a catalytic body.

[0002]

2. Description of the Related Art Catalytic combustion, which is surface combustion with a catalytic body, has many characteristics because the combustion method is completely different from ordinary gas phase combustion. For example, since the combustion temperature can be suppressed to as low as 1000 ° C. or lower, the generation of thermal NO _x can be reduced and the generation of hydrocarbons can be almost suppressed. Further, since the catalytic reaction is carried out on the catalyst surface, the combustor itself becomes a radiant body, and when used in a heater, comfortable radiant heating can be obtained. In addition, since the combustion temperature is low, there is little fear of flames, and there is an advantage that the combustor can be made compact because the space such as the combustion chamber that is normally required in the combustor is not required.

In radiant heating by catalytic combustion, the catalytic combustion temperature is limited, and therefore the amount of heat that can be extracted from a unit volume is limited. In order to extract a large amount of radiant heat, it is generally necessary to increase the area of the catalyst body.

The entire construction of the oil stove to which the catalytic combustion device is applied will be described in detail with reference to FIG. In the figure, 1 is a self-heating catalyst body having electrical conductivity (hereinafter, simply referred to as a catalyst body), 2 is a steam jet pipe for mixing the fuel oil vapor with combustion air, and 3 is for combustion Air supply port,
Reference numeral 4 denotes a fuel mixture supply duct for supplying a fuel mixture, which is a mixture of petroleum vapor and combustion air, to the catalyst body 1. Reference numeral 5 is an electrode for energizing and heating the catalyst body 1.
The petroleum vapor is supplied from the vaporizer 6 to the vapor ejection pipe 2, and the oil ejected from the oil tank 7 is supplied to the vapor ejection pipe 2. Further, the combustion air is supplied from the outside to the combustion air supply port 3 by the air supply fan 9 through the intake pipe 8. 10 is an exhaust duct through which the combustion gas reacted by the catalyst body 1 passes, 11 is a heat recovery exchanger for recovering the heat of the combustion gas to the carburetor 6, and 12 is a heat recovery exchanger 11.
The heat exchanger that conveys the heat that could not be completely collected by the convection fan 13 into the room for heating, and 14 is an exhaust pipe through which the heat-exchanged combustion gas passes.

A temperature sensor 1 which is not in contact with the vicinity of the catalyst body 1
5 is provided to detect the temperature of the catalyst body 1. The temperature sensor 15 detects infrared rays from the catalyst body 1 and obtains its temperature. Also, 16
Is a control circuit board on which electronic components forming a control circuit for controlling each component are mounted. Reference numeral 17 denotes a heat-resistant glass window, which is provided in order to transmit radiant heat from the catalyst body 1 into the room and obtain effective radiant heating.

However, in such a structure, if the combustion area of the catalyst body is increased in order to extract a large amount of radiant heat, not only the heater main body becomes large, but also the catalyst main body is used for temperature gradient and preheating due to heat transfer or the like. Since the combustion unevenness caused by the non-uniformity of the air-fuel mixture becomes large, the amount of carbon monoxide (CO) harmful to the human body and the amount of hydrocarbons (HC) causing odor increase. Further, it is considered that the temperature difference on the surface of the catalyst body caused by the uneven combustion promotes the local deterioration of the catalyst body.

Conventionally, ceramics such as cordierite and alumina have been used after being processed into a honeycomb shape for the catalyst carrier, but it is difficult to manufacture them as a large single plate. is there.

Therefore, as a method of increasing the area of the catalyst body and facilitating the manufacture thereof, it is conceivable to use the cylindrical catalyst body 18 as shown in FIG. Such a catalyst body 1
The heater in which No. 8 is used has a space 20 between the catalyst body 18 and a cylindrical heat-resistant glass window 19 provided around the catalyst body 18,
Petroleum vapor is ejected from below the catalytic body 18 through the vapor ejection pipe 2 so as to be mixed with combustion air, and burned on the surface of the catalytic body 18. Other configurations are almost the same as those in FIG. 4, and the same reference numerals are given. In this case, the catalyst 18 can take out radiant heat efficiently with a smaller volume than the flat plate type.

[0009]

However, even in this method, since the fuel is simply supplied to the surface of the catalyst body, the fuel tends to stay downward due to gravity.
A concentration gradient of the air-fuel mixture occurs in the vertical direction. For this reason, uniform combustion cannot be obtained in the vertical direction of the catalyst body, resulting in uneven combustion and uneven surface temperature distribution.
Not only is it difficult to suppress the generation of HC and HC, but it also causes local deterioration of the catalyst body.

Therefore, an object of the present invention is to increase the area of the catalyst body and to facilitate the production, and to make the surface temperature distribution of the catalyst body uniform.

[0011]

In order to achieve the above object, the present invention has a cylindrical catalyst body which is supplied with fuel by a fuel supply means and burns on the surface, and the inside of the inner wall of the catalyst body is formed. A tubular body is provided in the space, a plurality of through holes facing the inner wall of the catalyst body are provided in the tubular body over substantially the entire inner wall, and the fuel is supplied from the inside of the tubular body by the fuel supply means.

[0012]

According to the catalytic combustion apparatus having such a structure, the fuel supplied from the fuel supply means flows into the inside of the tubular body, passes through the plurality of through holes of the tubular body, and almost the entire inner wall of the catalyst body. Reach As a result, the combustion on the catalyst body is made uniform, and since the catalyst body has a cylindrical shape, it has a large area, a large amount of radiant heat can be taken out, and a small volume is required, which facilitates manufacturing.

[0013]

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

FIG. 1 is a sectional view showing an example in which an embodiment of the present invention is applied to a petroleum stove which is a heater.

The catalyst body 21 in this oil stove is
It has a tubular shape and has electrical conductivity, and a plurality of exhaust holes 21a are formed over the entire length thereof. Electrodes (not shown) for electrically heating the catalyst body 21 are attached at predetermined positions on the upper and lower ends of the catalyst body 21. A space 23 is formed in the inner space of the inner wall of the catalyst body 21, and a fuel mixture supply pipe 25 as a tubular body is provided. The fuel mixture supply pipe 25 is made of stainless steel, and the catalyst body 21
It is formed to the same length as. The fuel mixture supply pipe 25 is formed with a plurality of through holes 25a over its entire length. Here, since the fuel is supplied from below, the through holes 25a are formed to be large or large on the upper side where the fuel is hard to reach, and conversely, small or small on the lower side in order to obtain a uniform combustion state. desirable.

A cylindrical heat-resistant glass window 29 is provided on the outer peripheral side of the catalyst body 21 to form an exhaust duct space 27 through which combustion gas reacted in the catalyst body 21 passes. The heat resistant glass window 29 transmits the radiant heat from the catalyst body 21 to the room,
This is for obtaining effective radiant heating, and the catalyst body 21 and the fuel mixture supply pipe 25 are fixed to the upper and lower ends by disk-shaped fixing plates 31 and 33.

The lower fixing plate 33 is fixed to a partition plate 37 in a casing 35 of the oil stove, and a circular fuel supply hole 33a is formed at the center thereof. Below the fuel supply hole 33a, a vapor ejection pipe 41 as a fuel supply means having a carburetor 39 is installed. The vapor jet pipe 41 is for mixing the vapor of petroleum, which is a fuel, with the combustion air, and through the fuel pipe 43, the petroleum tank 45 arranged at the rear of the petroleum stove supplies the petroleum.

The steam jet pipe 41 is fixed to an air guide member 47 mounted on the lower surface of the fixed plate 33, and the steam jet pipe 41 is fixed.
The air mixed with the oil jetted from the air guide member 47
It is supplied from the air hole 47a formed in the. Air holes 47
The combustion air flowing into a is supplied from the outside of the casing 35 through the intake pipe 49 and the air supply fan 51 through the combustion air supply port 53.

The combustion gas in the exhaust duct space 27 on the outer peripheral side of the catalyst body 21 passes through the exhaust holes 33b of the lower fixing plate 33 together with the diluted air flowing from the small holes 31a of the upper fixing plate 31, and the combustion gas exhaust port. It is discharged to 53. The heat of the combustion gas flowing out to the combustion gas discharge port 53 is recovered by the heat recovery exchanger 55 in the vaporizer 39. Heat recovery exchanger 5
The heat that cannot be completely recovered by 5 is transferred to the heat exchanger 59 that exchanges heat with the air sent by the convection fan 57, and the air that has passed through the heat exchanger 59 and is warmed is cooled by the casing 35.
The air is blown from the warm air outlet 61 in the lower part of the front of the room into the room for heating. On the other hand, the combustion gas that has passed through the heat exchanger 59 and has undergone heat exchange is discharged to the rear portion of the housing 35 through the exhaust pipe 63.

The heat-resistant glass window 29 and the oil tank 45 are separated from each other by a partition wall 65 in the housing 35.
In the heat insulating plate 67 arranged on the heat resistant glass window 29 side of 5,
A temperature sensor 69 that detects the temperature of the catalyst body 21 is provided. The temperature sensor 69 is a non-contact type that detects infrared rays radiated from the catalyst body 21, and is a petroleum tank 4
The temperature of the catalyst body 21 is calculated by inputting a detection signal to a control circuit provided on the lower part of the control circuit board 5 for controlling each component.

Next, the combustion operation of the oil stove constructed as described above will be described with reference to the flow chart shown in FIG.

First, the power switch is turned on to turn on the catalyst 21.
(Step 101), the temperature of the catalyst body 21 detected by the temperature sensor 69 changes to the activation temperature (usually 500).
(° C.) or higher (step 102), and if it is higher than the activation temperature, the valve of the vaporizer 39 is opened and the reaction gas, that is, the petroleum vapor ejected from the vapor ejection pipe 41 and the air supply fan 51 are used to draw the intake pipe The mixture with the combustion air supplied from 49 is supplied into the fuel mixture supply pipe 25 (step 103).

The reaction gas supplied into the fuel-air mixture supply pipe 25 reaches the upper side by the force of jetting, and flows out into the space 23 through the through hole 25a. Since a plurality of through holes 25a are formed from the lower end to the upper end of the fuel mixture supply pipe 25, the reaction gas flowing into the space 23 is evenly distributed over almost the entire inner wall of the catalyst body 21, and the fuel gas in the catalyst body 21 is discharged. The concentration distribution becomes uniform.

When the reaction gas reaches the inner wall of the catalyst body 21,
Since the catalyst body 21 has already reached the activation temperature or higher, it is ignited (step 105). After ignition, it is determined whether the temperature of the catalyst body 21 detected by the temperature sensor 69 is equal to or higher than a predetermined value (step 107), and if the temperature is equal to or higher than the predetermined value, the energization to the catalyst body 21 is stopped (step 109). .
After that, catalytic combustion is performed (step 111), the combustion gas passes through the exhaust hole 21a of the catalyst body 21, reaches the combustion gas discharge port 53 through the exhaust duct space 27, and passes through the heat exchanger 59, thereby convection. The heat exchanged with the air sent by the fan 57 and the warmed air is blown out from the warm air outlet 61 to heat the room. In addition, the combustion gas discharge port 53
Part of the combustion gas that has flowed out to the heat recovery exchanger 55 is recovered by the vaporizer 39, and the vaporization of petroleum in the vaporizer 39 is promoted.

Next, it is judged whether or not the combustion state is switched (step 113). The combustion state is set to two types, that is, weak combustion and strong combustion, as shown in FIG. That is, in weak combustion, the combustion amount is less than 500 kcal, the carburetor valve is off, fuel is not supplied, the air supply amount is constant, and the catalyst 21
Is always energized. On the other hand, in strong combustion, the combustion amount is 500 kcal or more, the carburetor valve is turned on, the fuel supply amount and the air supply amount are values according to the set combustion amount, and the catalyst body 21 is not energized. Since the catalyst body 21 is heated by the reaction once it is ignited, the energization is turned off in the strong combustion.

Returning to step 113, if the combustion state is strong, the fuel supply amount and the air supply amount are controlled according to the set combustion amount (step 115) (step 117). In the case of weak combustion, the vaporizer valve is turned off to stop the supply of the reaction gas (step 11
9), the catalyst body 21 is energized (step 121).

When petroleum vapor is supplied such as in the case of strong combustion as described above, the reaction gas spreads from the plurality of through holes 25a to the entire area of the catalyst body 21, so that the fuel concentration distribution in the catalyst body 21 is made uniform. The catalyst body 21
The uniform combustion is performed in the up and down direction, the surface temperature distribution becomes uniform, and not only the generation of CO and HC is suppressed, but also
Local deterioration of the catalyst body 21 is also prevented. In addition, the catalyst body 21
Since it has a cylindrical shape, even if it is small to some extent, it has a large area, a large amount of radiant heat can be taken out from the entire circumference of 360 degrees, manufacturing becomes easy, and the oil stove itself can be made compact.

Further, since the tubular catalyst body 21 need only be fixed at two positions of the fixing plates 31 and 33 at most, the temperature unevenness due to heat conduction can be suppressed smaller than that of a single plate. To be

[0029]

As described above, according to the present invention, a tubular body having a plurality of through holes is provided inside a tubular catalyst body, and fuel is supplied from the inside of the tubular body. As a result, the supplied fuel is evenly distributed over almost the entire inner wall of the catalyst body, uniform combustion is performed in the vertical direction of the catalyst body, and the surface temperature distribution becomes uniform, suppressing the generation of CO and HC. Not only can this be done, but local deterioration of the catalyst body can also be prevented. Further, since the catalyst body has a cylindrical shape, even if it is small to a certain extent, it has a large area, a large amount of radiant heat can be taken out, and the production becomes easy.

[Brief description of drawings]

FIG. 1 is a sectional view of an oil stove showing an embodiment of the present invention.

FIG. 2 is a flowchart showing a combustion operation in the oil stove shown in FIG.

FIG. 3 is an explanatory view showing a weak combustion state and a strong combustion state in the oil stove shown in FIG.

FIG. 4 is a perspective view showing the internal structure of a conventional oil stove.

FIG. 5 is a sectional view of an oil stove showing another conventional example.

[Explanation of symbols]

 21 catalyst body 25 fuel mixture supply pipe (tubular body) 25a through hole 41 vapor ejection pipe (fuel supply means)

Claims (1)

[Claims] 1. A catalytic combustion device for supplying fuel to a porous catalyst body by a fuel supply means to burn the catalyst body on the catalyst body, wherein the catalyst body has a cylindrical shape, and an inner space of an inner wall of the catalyst body is provided. A catalytic combustion characterized in that a tubular body is provided, a plurality of through holes facing the inner wall of the catalyst body are provided in the tubular body over substantially the entire area of the inner wall, and the fuel is supplied from the inside of the tubular body by the fuel supply means. apparatus.