JP2001108206A - Catalyst combustor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a catalyst combustor which can obtain a combustion gas whose NOx value is zero by subjecting a lean mixture to good catalytic combustion. SOLUTION: A heat transfer cylinder 6 mounted with a catalytic body 7 on its outer periphery is connected to a vaporizing pot 1 comprising a vaporizing heater 2, by which supplied combustion oil is vaporized, and the veporized gas is premixed with combustion air which is three times of theoretical air to produce a lean mixture having excessive air quantity. Further, a guide plate 8 is provided above the cylinder 6 so as to cover the cylinder 6 including the outer periphery of the catalytic body 7. Thus an inversely U-shaped mixing path 9 is formed from the pot 1 toward the catalytic body 7. Accordingly, the catalytic body 7 can be heated to an activation temperature in an economical manner by means of the heater 2, and at the same time, since mixing of the lean mixture is well conducted in the inversely U-shaped path 9, catalytic combustion whose NOx value is zero can be achieved.

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 constituting a combustion portion of a heater such as a domestic water heater or a fan heater.

[0002]

2. Description of the Related Art Conventionally, in this type of fuel, as disclosed in, for example, Japanese Patent No. 2646526, fuel oil is vaporized by a vaporizer provided with a vaporizing heater, and the vaporized gas and the combustion air are vaporized. The present invention provides a combustor having a low NOx value by catalytically combusting the premixed gas in the catalyst body.

[0003]

However, this conventional apparatus requires two heaters for preheating the carburetor and for heating the catalyst to the activation temperature, which is uneconomical and requires the catalyzer from the vaporizer. If the mixture path through which the air-fuel mixture flows is short, especially in the case where a lean air-fuel mixture with an excessive amount of air is catalyzed by combustion, if the air-fuel mixture is short, the lean air-fuel mixture will not be sufficiently mixed and will be partially shaded. Which have problems such as burning out of the catalyst body and incomplete combustion, and new problems that simply lengthening the mixing path make the whole appliance large and unsuitable for household appliances Met.

[0004]

The present invention focuses on this point and solves the above-mentioned drawbacks. In particular, the present invention comprises a vaporizing heater for vaporizing supplied fuel oil and premixing the vaporized gas with combustion air. A vaporizer pot that forms a lean mixture with an excess amount of air, a catalyst body provided on the outer periphery of a heat transfer cylinder erected at the upper end of the vaporizer pot, and performs catalytic combustion by flowing the lean mixture. A guide plate that covers the upper part of the heating cylinder, and a mixing path having an inverted U-shaped cross section is formed between the vaporization pot and the catalyst body.

If the heat transfer cylinder is integrally formed with the vaporization pot,
The heat conduction is performed smoothly, and the structure is easy.

If a collecting plate is provided at the boundary between the vaporizing pot and the mixing passage, the air-fuel mixture once collected by the collecting plate is diffused and circulates through the mixing passage, so that the mixing can be performed well.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION If the vaporization heater 2 is energized to heat the vaporization pot 1 to a predetermined vaporizable temperature, this heat is transmitted to the catalyst 7 via a heat transfer cylinder connected to the vaporization pot 1, And the vaporization pot 1 in which the catalyst body 7 reaches the activation temperature
The temperature is detected by the temperature sensor 12, and fuel oil is sprayed into the vaporization pot 1, and at the same time, combustion air of about three times the theoretical air amount is supplied to form a lean air-fuel mixture having an excessive air amount.

Further, the formed lean air-fuel mixture is once converged by the upper collecting plate 10 and then satisfactorily mixed through the mixing passage 9 having an inverted U-shaped cross section. Then, the combustion gas after combustion is released into a room or the like and used for heating.

Therefore, the combustion temperature is low due to the catalytic combustion of the lean mixture, the NOx value in the combustion gas is almost zero, and an environmentally friendly low-pollution combustion device can be provided. For vaporization pot 1 and catalyst 7
Since it is also useful, one is very economical.

Further, the mixing passage 9 is formed in an inverted U-shape in cross section, and can be made a sufficiently long mixing passage 9 while keeping the whole compact. Can be obtained.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a catalytic combustion apparatus according to the present invention will be described with reference to an embodiment shown in the drawings. Reference numeral 1 denotes an aluminum die-cast evaporating pot in which an evaporating heater 2 is cast at an upper portion, and a jet port 4 for blowing combustion air from a combustion fan (not shown) through an air passage 3 communicates with one side. , The spout 4
Is provided with a nozzle 5 which communicates with an electromagnetic pump (not shown) and sprays fuel oil. The nozzle 5 premixes the vaporized gas with about three times the theoretical air amount of combustion air to form a lean mixture.

Numeral 6 denotes a hollow cylindrical heat transfer cylinder which is provided upright at the upper end of the vaporization pot 1 and is made of aluminum and is integrally formed with the vaporization pot 1 and has a palladium-based catalyst 7 closely attached to the outer periphery thereof. The heat of the vaporization heater 2 for preheating the vaporization pot 1 is transmitted to the catalyst body 7 and the catalyst body 7 is heated to an activation temperature of 25 before the start of combustion.
It is to be heated to 0 ° C or higher.

Numeral 8 covers the upper part of the heat transfer cylinder 6 from the outer periphery of the catalyst body 7 which is in close contact with the heat transfer cylinder 6, and allows the lean air-fuel mixture from the vaporization pot 1 to flow through the heat transfer cylinder 6 to the outer peripheral catalyst body 7. A guide plate that forms a mixing passage 9 having an inverted U-shaped cross section. By forming a relatively long mixing passage 9 while being compact, a lean air-fuel mixture can be sufficiently mixed, and a uniform air-fuel mixture with no shading can be obtained. Good catalytic combustion is performed.

Reference numeral 10 denotes a collecting plate provided at a boundary portion between the vaporizing pot 1 and the mixing passage 9, which has a circulation hole 11 formed only in the center, and once concentrates the lean mixture just formed in the vaporizing pot 1. After passing through the flow hole 11, the mixture is discharged into the mixing path 9, so that mixing is promoted.

Reference numeral 12 denotes a temperature sensor composed of a thermistor or the like for detecting the temperature of the vaporization pot 1, which detects the activation temperature of the catalyst 7 above the vaporization temperature of the vaporization pot 1 as a preset vaporization pot 1 temperature. , The start of combustion and the energization of the vaporization heater 2 are controlled.

Next, the operation of this embodiment will be described. When the vaporization heater 2 is energized to reach the vaporizable temperature at which the vaporization pot 1 is heated, the heat of the vaporization pot 1 is applied to the catalyst 7 via the heat transfer tube 6, and the catalyst 7 is heated to 250 ° C.
When the activation temperature is reached, the temperature sensor 12 detects the activation temperature as the temperature of the vaporization pot 1, and supply of fuel oil and combustion air is started several minutes after the start of energization.

In the vaporization pot 1, the vaporized gas of the fuel oil sprayed and vaporized from the nozzle 5 and the combustion air supplied from the ejection port 4 and having a volume approximately three times the theoretical air amount are mixed to form a lean air-fuel mixture. Then, the mixture is supplied to the mixing passage 9 through the flow hole 11 of the collecting plate 10, and at this time, the lean mixture is once concentrated to pass through the flow hole 11 and diffused after passing, thereby facilitating the mixing. It is.

Further, the lean mixture after passing through the collecting plate 10 flows through the mixing passage 9 having an inverted U-shaped cross section, and is supplied to the catalyst body 7 in a sufficiently well-mixed state without density. Since the catalytic combustion is carried out by the catalytic body 7 at the activation temperature and the catalytic combustion is carried out by a lean mixture, the combustion temperature is suppressed to a low level, and the NOx value is further suppressed accordingly, and the NOx in the combustion gas is reduced.
The x value is almost zero, and clean heating can be performed.

Further, by making the mixing passage 9 have an inverted U-shaped cross section,
A relatively long mixing passage 9 is formed in spite of the compactness, and a lean mixture in which shading tends to occur can be uniformly mixed, so that burning of the catalyst 7 and incomplete combustion can be reliably prevented.

On the other hand, since the catalyst 7 is heated to the activation temperature by using the vaporization heater 2 for preheating the vaporization pot 1, only one heater is sufficient and it is economical. This eliminates the need for energizing the vaporization heater 2 while maintaining the temperature.

Next, another embodiment shown in FIG. 2 will be described.
Heat transfer cylinder 6 This is not integrally molded with the vaporization pot 1 by aluminum die casting, but is formed by fitting separately formed parts and integrating them with an adhesive or the like. It is.

[0022]

As described above, according to the present invention, NOx
It can provide an extremely clean domestic heater with a value of zero, and the vaporization pot and the catalyst can be heated by one heater, the number of parts is small, and it is very economical. It is an object of the present invention to provide a catalyst device having various advantages such that a lean mixture is well mixed and burning out and incomplete combustion of a catalyst body can be surely prevented.

Further, since the heat transfer cylinder is integrally formed with the vaporization pot, the heat transfer to the heat transfer cylinder is smoothly and efficiently performed, the configuration is easy, and the assembly is easily performed.

Further, by providing the collecting plate, the lean mixture is focused and diffused, and the mixing is further promoted.

[Brief description of the drawings]

FIG. 1 is a sectional view of a catalytic combustion device to which an embodiment of the present invention is applied.

FIG. 2 is a sectional view showing another embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vaporization pot 2 Vaporization heater 6 Heat transfer cylinder 7 Catalyst 8 Guide plate 9 Mixing path 10 Assembly plate

Claims (3)

[Claims] 1. A vaporizing pot which is provided with a vaporizing heater, vaporizes supplied fuel oil, and pre-mixes the vaporized gas with combustion air to form a lean air-fuel mixture with an excessive amount of air. A catalyst body provided on the outer periphery of the heat transfer cylinder and catalyzed by the flow of a lean air-fuel mixture, and a guide plate for covering the upper part of the heat transfer cylinder from the outer periphery of the catalyst body. A catalytic combustion device characterized by forming a letter-shaped mixing passage. 2. The catalytic combustion device according to claim 1, wherein the heat transfer cylinder is formed integrally with a vaporization pot. 3. The catalytic combustion apparatus according to claim 1, wherein a collecting plate having a flow hole formed only in the center is provided at a boundary between the vaporizing pot and the mixing passage.