JPS62242710A - Combustion device - Google Patents

Abstract

PURPOSE:To restrict a generation of nitrogen oxide as well as to prevent a discharging of carbon monoxide or odor substance or the like from being discharged by a method wherein a radiator body crossing at a flow passage between a flame port and a discharging gas outlet port and having its upstream side surface opposed to a wall of a combustion chamber is arranged in the flow passage and then an oxidation catalyst layer is arranged. CONSTITUTION:A radiator body 7 is inclined and arranged within a combustion chamber 5 in such a way as it may cross with a center of flow passage connecting a flame port 1 with a discharged gas outlet port 6, a plane of the discharging gas flow passage facing to its upstream side is directed forwardly and the discharging gas outlet port 6 is provided with an oxidation catalyst layer 10 having platinum carried on a honeycomb alumina carrier. A part of a flame F formed at the flame port 1 is contacted with the radial body 7 and hot discharging gas of which reaction is finished at a lower part of the radiator body is also heat exchanged with the radiator body 7, so that the radiator body 7 becomes red heated to radiate heat which is supplied from a radiation window 9 to the front face through a heat-resistant glass 8. A discharging gas temperature at a downstream side of the radiator body 7 is excessively decreased due to the thermal radiation and so a generation of nitrogen oxide can be restricted as less as possible. In turn, even if a flame F having non-reacted substance in it is contacted with the radiator body, an oxidation reaction is further promoted there and almost of all carbon monoxide or odor substances are removed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a radiant combustion device used for space heating, heating, drying, etc.

2. Description of the Related Art In general, so-called radiant combustion devices, which include a radiator in a combustion chamber and radiate a portion of the combustion heat for heating and space heating, are widely used as gas or oil combustors.

Conventionally, as shown in Japanese Unexamined Patent Publication No. 59-183205, heat is radiated directly from the flame opening where the flame is formed, or the radiator is heated with high-temperature exhaust gas after the combustion reaction is completed. A method was adopted to do so.

Problems to be Solved by the Invention In the conventional method described above, 20 to 30% of the combustion heat can be used as radiant heat, but nitrogen and oxygen in the air used for combustion are exposed to high temperatures for a relatively long period of time, and a large amount The disadvantage was that nitrogen oxides were generated. That is, in the first example, although part of the combustion heat is radiated at the flame mouth, the vicinity of the flame tip where the temperature is highest is already far from the flame mouth, and a sufficient cooling effect cannot be obtained. The high-temperature exhaust gas continues to flow to the exhaust port, and the amount of nitrogen and wood oxides produced during this period reaches tens of ppm to even hundreds of ppm. Similarly, in the case of the second example, when a radiator is installed in the flue gas flow path, if the exhaust gas is not brought into contact with the radiator after the combustion reaction has completely completed, odor and monoxide will be generated due to incomplete combustion. Since carbon is generated, the flame and the radiator must be kept at a sufficient distance, resulting in the generation of a large amount of nitrogen oxides in the exhaust gas during this time.

In general, the production rate of nitric oxide in a mixture containing oxygen and nitrogen is d(No)/d(XIC)"eXp(-135000
7'ELT lN2) [:02] (Gl
ick, at, al, ;I, Chem, Ph
ysics.

27(4), 850-857.1957), for example, when kerosene combustion is performed at an air ratio of 1:4, the atmosphere is calculated from the above equation.

Approximately 15 ppm when exposed to an air temperature of 16oO℃ for just 1 second
It is calculated that NO occurs. If this temperature is set to 1000°C, the amount of No generated will be 0.01 ppm or less, and the impact on the environment can be almost eliminated.

The present invention solves the above conventional drawbacks, and provides a radiant combustion device that suppresses the generation of nitrogen oxides and does not emit carbon monoxide, odor substances, etc. into exhaust gas.

Means for Solving the Problems The technical means used in the present invention to solve the above conventional problems is to reduce the flame or exhaust gas between the flame mouth where the flame is formed and the exhaust gas outlet where the exhaust gas is discharged. In the flow path of
A radiator whose upstream surface faces the combustion chamber wall made of a heat ray transparent material is disposed at a position intersecting with this flow path and near the flame, and the downstream side of this radiator is oxidized. It is equipped with a catalyst layer.

Effect: With the above means, the radiator prevents the flame and exhaust gas in the combustion chamber from becoming extremely hot, suppresses the generation of nitrogen oxides, provides a combustion device with high radiation efficiency, and also provides a combustion device with high radiation efficiency. The oxidation catalyst layer can completely oxidize and remove carbon monoxide and unburned substances that cause odor and soot.

EXAMPLE Hereinafter, an example of the present invention will be described based on the accompanying drawings.

In Fig. 1, reference numeral 1 designates a horizontally elongated flame port, through which liquid fuel that is pressure-fed from a pump 2 and vaporized in a vaporization chamber 3 is premixed with a portion of air supplied from an air blower 77 and then ejected. ,
The remaining air from the blower fan is supplied to this and the flame F
It burns in the combustion chamber 6 while forming. An exhaust gas outlet 6 is opened in the upper part of the combustion chamber 6 at a position approximately diagonal to the flame port 1, and a flow path intersects with the center of the flow path connecting the flame port 1 and the exhaust gas outlet 6 in the combustion chamber 6. The radiator is erected at an angle. The surface of the radiator T facing upstream of the exhaust gas flow path faces forward, and a radiation window 9 equipped with heat-resistant glass 8 is provided in the front of the combustion chamber 6 facing this surface. Further, the exhaust gas outlet 6 is provided with an oxidation catalyst layer 1o in which platinum is supported on a honeycomb-shaped alumina carrier. 11 is a fuel tank, and 12 is a sheathed heater for heating the vaporization chamber.

In the above configuration, a part of the tip of the flame F formed at the flame port 1 is in contact with the radiator 7, and the high temperature exhaust gas whose reaction has finished at the lower part is also heat exchanged with the radiator 7. , the radiator 7 becomes red-hot and radiates heat, and heat is supplied to the front surface from the radiation window 9 through the heat-resistant glass 8. On the downstream side of the radiator 7, the temperature of the exhaust gas is significantly lowered by the heat dissipation, and therefore, as is clear from the reaction rate equation, the production of nitrogen oxides can be suppressed to a very small amount. On the other hand, since the radiator 7 is in a red-hot state (aOO~900°C), even if the flame F containing unreacted substances comes into contact with it, the oxidation reaction is still promoted, and - carbon oxide and odorous substances (aldehydes, etc.) Ketones, etc.) are mostly removed, but the exhaust gas is also completely purified by the oxidation catalyst layer 1o provided at the exhaust gas outlet 6, and the exhaust gas discharged from the combustion chamber 6 is free of nitrogen oxides, carbon monoxide, and odorous substances. Both of these can be reduced or eliminated. In addition, since a part of the radiator T can be brought close to the position where it comes into contact with the flame F, the temperature can be raised sufficiently, and the amount of heat radiated to the front surface can also be increased more than before, increasing the radiation efficiency. It becomes an expensive combustion device. Note that the radiator 7 may be composed of a metal mesh made of heat-resistant chromium steel or a punched plate, but it is more preferable to use a honeycomb-shaped ceramic plate, which promotes oxidation reaction, improves emissivity, and has excellent heat resistance. Effective. In particular, since the upstream surface of the radiator 7, which is at a higher temperature, faces the radiation window 9, there is no loss due to heat conduction as in the conventional case, and highly efficient radiant heat radiation is possible.

Further, the oxidation catalyst layer 1o is not limited in its position as long as it is downstream of the radiator 7, and can be placed in the temperature range where the catalytic action is most active. Therefore, for example, as shown in FIG. 2, a honeycomb structure 7 whose main component is alumina, in which a radiator 7 and an oxidation catalyst layer 1o are integrated, is used, and the upstream side is left untreated as the radiator 7, and the downstream side is left untreated. It is also possible to support a platinum catalyst on the side to form the oxidation catalyst layer 10, and it is possible to provide a simple, inexpensive, and effective combustion device for high emissivity and low nitrogen oxides.

Furthermore, as shown in FIG. 3, the flame port 1 is configured to have a circular structure to eject the premixed gas in the circumferential direction, and a cylindrical radiator 7 having the same diameter or a slightly smaller diameter as this flame port is erected. By providing the exhaust gas outlet 6 approximately at the upper center of the radiator 7, the above effects can be obtained as is, and the combustion device can radiate heat in the entire circumferential direction, making it effective for use as an indoor heating device, for example. It is true. Even in this case, the oxidation catalyst layer 1o may be provided in the vicinity of the exhaust gas outlet 6 as shown in FIG. 3, or may be integrated with the radiator 7 as shown in FIG. 4, without impairing the above-mentioned effects.

Although the above embodiments have mainly been explained using liquid fuel, the same applies to gaseous fuel (e.g. city gas).
The same effect can be achieved. Furthermore, in the above embodiment, the premixed fuel/air mixture gas is ejected from the flame port, and secondary air is further supplied to it to cause combustion.
The effect is the same even if all the combustion air is premixed, so-called full-stage combustion, or if only the fuel is supplied without premixing, so-called diffusion combustion. The effect is particularly significant when using single-molecule mixing or diffusion combustion, which tends to generate nitrogen oxides (that is, increases the flame temperature).

Effects of the Invention As described above, the present invention provides a structure in which the flame or exhaust gas flow path between the flame opening where the flame is formed and the exhaust gas outlet where the exhaust gas is discharged intersects with the flow path of the flame or the exhaust gas. A radiator whose upstream surface faces the combustion chamber wall made of a heat-transparent material is installed near the radiator, and an oxidation catalyst layer is provided downstream of the radiator to reduce nitrogen oxidation. It is possible to provide a combustion device that can suppress the generation of carbon monoxide, odor substances, etc., and increase the amount of radiant heat dissipation.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a main part of a combustion apparatus according to one embodiment of the present invention, and FIGS. 2, 3, and 4 are sectional views of main parts of a combustion apparatus according to other embodiments. 1...flame port, 6...combustion chamber, 6...
...Exhaust gas outlet, 7...Radiator, 9...
... Radiation window, 10... Oxidation catalyst layer. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 3
Figure 4

Claims (4)

[Claims] (1) A flame port for ejecting fuel or a mixed gas of fuel and air to form a flame; a combustion chamber having the flame port disposed at the bottom and an exhaust gas outlet at the top; a radiator disposed near the flame intersecting with the center of the flame or exhaust gas flow path connecting the flame port and the exhaust gas outlet; and an oxidation catalyst layer disposed downstream of the radiator; The radiator has a surface facing upstream of the exhaust gas flow path facing the wall surface of the combustion chamber, and at least a portion of the wall surface of the combustion chamber facing the radiator is made of a heat ray transparent material. (2) The combustion device according to claim 1, in which the radiator and the catalyst layer are integrated. (3) The combustion device according to claim 1, wherein the radiator is provided at a position in contact with a part of the flame formed at the flame nozzle. (4) The radiator is made cylindrical, the mixed gas outlet at the flame port is made larger than the outer diameter of the radiator, and the exhaust gas outlet is made smaller than the inner diameter of the radiator, so that these three parts are approximately A combustion device according to claim 1 or 2 or 3, which is arranged concentrically.