JPH11264514A - Catalyst combustion device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a low-NOx catalyst combustion device improved in heat back and capable of saving power. SOLUTION: A device is provided with a catalyst body 8 for increasing the temperature of mixed air by providing a vaporization heater 2 and erecting a heat-absorbing cylinder 7 at the upper edge of a vaporization pot 1 for supplying rare mixed air with excessive amount of air and circulating the rare mixed air from the vaporization pot 1 into the heat-absorbing cylinder 7 for catalyst combustion. Therefore, the heat of the catalysist body 8 can be positively returned to the vaporization pot 1 via the heat-absorbing cylinder 7 and power can be saved without energizing the vaporization heater 2 during combustion.

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, as disclosed in Japanese Patent Application Laid-Open No. 2-238206, a fuel gas is heated to a catalyst activation temperature by a preheater and then heated in a catalytic combustion region. The purpose of the present invention is to provide a combustion method that does not generate harmful substances such as NOx by performing catalytic combustion and then performing gas phase combustion in a gas phase combustion region.

[0003]

However, in this conventional device, it is necessary to keep the preheater energized at all times.
It is uneconomical in that it consumes a large amount of power and requires a control circuit, and has the drawback that it takes time to raise the temperature of the catalyst to the activation temperature of the catalyst, and that it is difficult to maintain this temperature and the structure becomes complicated. Was something.

[0004] This prior art is related to an industrial gas turbine, and its application to a small household heater or the like has great difficulty and cannot be easily realized. If the concentration is increased, generation of NOx cannot be suppressed.

[0005]

The present invention focuses on this point and solves the above-mentioned drawbacks. In particular, the present invention is provided with a vaporizing heater for vaporizing supplied fuel oil, and preliminarily using this vaporized gas as combustion air. A vaporization pot that mixes and supplies a lean mixture with an excess amount of air, a catalyst body that catalyzes combustion by flowing the lean mixture from the vaporization pot and raises the temperature of the mixture, and flows out of the catalyst body A combustion chamber for performing gas-phase combustion of the air-fuel mixture, and the catalyst body is provided in a heat-absorbing cylinder provided upright at an upper end of a vaporization pot.

[0006]

A fuel oil as a fuel is sprayed into a vaporization pot 1 heated to a vaporizable temperature by a vaporization heater 2 and a combustion air having an air ratio of about 2 is supplied to the vaporization pot 1 for premixing to increase the amount of air. To form a lean mixture.

The lean mixture flows into a honeycomb-shaped catalyst body 8 communicated above the vaporization pot 1, and is heated by the heat generated by reacting on the catalyst 11 formed on the support 9. Due to heat exchange with 8, the lean mixture further raises this temperature.

Next, the lean air-fuel mixture flows out of the catalyst body 8, flows into the combustion chamber 13 above the catalyst body 8, and is ignited by the ignition means 20, so that it can be burned at a high temperature. The lean mixture performs gas phase combustion.

Further, the combustion gas after the gaseous phase combustion in the combustion chamber 13 is discharged into the room from the hot air outlet 25 of the main frame 24 by blowing air from the convection fan 21 to heat the room.

On the other hand, part of the heat of the catalyst body 8 whose temperature has risen due to the catalytic combustion is reliably heated back to the vaporization pot 1 via the heat absorbing cylinder 7 containing the catalyst body 8, and the combustion of the vaporization heater 2 during combustion. It is possible to stop power supply and save power.

[0011] Further, because of the gas phase combustion of a lean mixture, the NOx value in the combustion gas is extremely small, and it is the first small-sized household heater to provide a low-pollution combustion device that has little effect on the environment and is friendly to humans. You can do it.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment in which a catalytic combustion device according to the present invention is provided in a fan heater of a heater will be described. Reference numeral 1 denotes a vaporization pot made of aluminum die-cast in which a vaporization heater 2 is cast at an upper portion, and an ejection port 5 for blowing out combustion air from a combustion fan 3 through an air passage 4 communicates with one side thereof. The jet port 5 is provided with a nozzle 6 which communicates with an electromagnetic pump (not shown) and sprays fuel oil. The nozzle 6 forms a premixed gas of the vaporized gas and the combustion air and constitutes a mixture supply means.

Numeral 7 denotes a cylindrical heat absorbing cylinder which is erected at the upper end of the vaporizing pot 1 and is formed integrally with the vaporizing pot 1 and has a cylindrical catalyst body 8 which communicates with the inside of the vaporizing pot 1 inside. The heat generated by the catalytic combustion of the catalyst body 8 is reliably heated back to the vaporization pot 1.

The catalyst body 8 has a wash coat layer 10 formed on one side of a support 9 made of a corrugated metal sheet.
Here, a catalyst 11 comprising palladium, platinum or (based on palladium or platinum) and one or more cocatalysts selected from silver, gold, platinum, palladium, ruthenium, rhodium or iridium. After coating and firing, the support 9 is spirally wound and
The catalyst 1 is housed in a honeycomb shape.
At the time of activation of 1, the catalytic combustion which is a chemical reaction is performed by the flow of the air-fuel mixture.

Reference numeral 13 denotes a flat box-shaped combustion chamber which communicates with the upper part of the catalyst body 8. The connection part 14 is provided at one end to cover the outer periphery of the heat absorbing cylinder 7 and communicates with the catalyst body 8. A discharge portion 15 having an upper opening for discharging combustion gas is provided, and a meandering flow passage 17 formed of an alumina-based heat insulating material 16 loaded inward between the connection portion 14 and the discharge portion 15 is further provided. To ensure a sufficient length of the flow passage 17 to complete the combustion even in the gas phase combustion in which the combustion amount is increased. In this case, in order to obtain a stable gas phase combustion, the flow passage 17 is required.
Has an inner diameter of 35 mm, which is the same diameter as that of the catalyst body 8, and has a flow passage 17 having a length of 800 mm for a maximum combustion amount of 5200 kcal / h. After the temperature reaches the activation temperature, gas phase combustion is performed.

Further, the flow passage 17 is compact as a folded path having two U-shaped passages, and a gap 18 is formed between the heat insulating material 16 and the wall surface of the combustion chamber 13 so as to be made of stainless steel. Expansion of the combustion chamber 13 due to heat,
The heat insulating material 16 is prevented from being damaged by shrinkage, and the heat insulating material 16 prevents heat in the flow passage 17 from escaping outward to promote gas phase combustion.

Reference numeral 19 denotes a flame detection flame rod provided immediately above the catalyst body 8 together with an electrode type ignition means 20. The flame rod 19 is mounted on the back surface of the combustion chamber 13 at a position facing the convection fan 21 and blows air from the convection fan 21. , And keeps good followability especially at the time of fire extinguishing.

Reference numeral 22 denotes a combustion chamber 13 erected on a partition plate 23.
The indoor air blown by the convection fan 21 is heated with the combustion gas discharged from the discharge section 15 of the combustion chamber 13 by the heat shield frame that covers the hot air outlet 25 in the front of the main body frame 24.
It is to guide.

Reference numeral 26 denotes a cooling passage 27 between the heat insulating frame 22 and the upper surface.
Is formed, and a part of the air blown by the convection fan 21 is circulated as cooling air, thereby suppressing a rise in the temperature above the main body frame 24.

Reference numeral 28 denotes a fan cover of the convection fan 21;
9 is a burner cover of the vaporization pot 1. Reference numeral 30 denotes an operation unit provided on the upper part of the main body frame 24, 31 denotes a tank lid for taking a cartridge tank (not shown) into and out of the main body frame 24, and 32 denotes a lower plate.

Next, the operation of this embodiment will be described. When the vaporization heater 2 is energized and the vaporization pot 1 is heated to reach a vaporizable temperature, first, combustion air is supplied from the combustion fan 3, and when the amount of air is stabilized, the nozzle 6
The fuel mixture is sprayed from the fuel mixture to form a premixed gas. At this time, the premixed gas remains at the air ratio of 1 because the catalyst body 8 has not been heated yet and is at room temperature. 8 and is ignited by the ignition means 20 in the combustion chamber 13 and FIG.
At the time of ignition, normal flame combustion is performed as shown in
This flame combustion is the maximum thermal combustion.

When the catalyst body 8 is heated by the flame combustion, and reaches 250 ° C. or more of the activation temperature of the catalyst, this is detected by a temperature sensor, a timer count from operation, ignition, or the like, and the amount of fuel is reduced. It is set so that the outgoing air ratio is close to 2.

As a result, a lean air-fuel mixture is formed in the vaporization pot 1 and flows into the catalyst body 8 which has reached the activation temperature, so that the catalyst 11 reacts the fuel and air in the catalyst body 8. The temperature of the air-fuel mixture rises due to catalytic combustion to occur, and the air-fuel mixture of 120 to 150 ° C. in the vaporization pot 1 is rapidly heated to 800 to 900 ° C. in the catalyst body 8, and the transient state of FIG. After that, it is ignited by a self-ignition phenomenon in the combustion chamber 13 to perform gas phase combustion at 1200 to 1500 ° C.

The flow passage 17 in the combustion chamber 13 in which the gas phase combustion is performed has a meandering, compact and long combustion region, so that the maximum combustion amount is 5200 kcal /
Even if it takes a long time to complete the combustion with a large combustion amount of h, the vapor phase combustion can be surely completed in the combustion chamber 13, and therefore, the combustion gas released from the post-combustion discharge unit 15 is convectively discharged. The room 21 is heated by blowing hot air from the hot air outlet 25 by blowing air from the fan 21. However, since heating is performed by burning a lean mixture, NO
The x value is 1 to 20 PPm.
This is an extremely low value with respect to the Ox value of 110 to 120 PPm, and can provide a low-pollution heater that has little effect on the environment and people.

On the other hand, the vaporization pot 1 has a closed structure of the combustion chamber 13 and cannot obtain heat back from the combustion gas. However, since the catalyst body 8 is held by the heat absorbing cylinder 7 erected at the upper end of the vaporization pot 1. 800-90 by catalytic combustion of chemical reaction
Heat is received from the catalyst body 8 which has been heated to 0 ° C., and can be heated back to the vaporization pot 1 through the heat absorption cylinder 7. It can be stopped to save power.

Further, by integrally molding the heat absorbing cylinder 7 with the vaporization pot 1, the production is extremely easy, and the heat of the catalyst body 8 can be reliably heated back to the vaporization pot 1.
The whole can be held firmly.

The catalyst 8 is composed of the catalyst 11 containing palladium as a main component, and the catalyst 11 is applied to only one surface of the support 9. The heat is dissipated by heat conduction to the wall surface through which only the air-fuel mixture flows, and the catalyst body 8 raises its temperature to 750-95.
The temperature can be maintained at 0 ° C., and there is no fear of melting or misfiring due to a rise in temperature, and good catalytic combustion can always be obtained.

Next, a second embodiment shown in FIG. 8 will be described. An adjusting member 33 for adjusting the amount of heat back is provided between the heat absorbing cylinder 7 and the catalyst body 8, and is made of aluminum or stainless steel wool. The amount of heat back can be adjusted by changing the thermal conductivity by changing the material of brass, copper, and the material, and the amount of heat back can be easily adjusted without changing the shape and size. 1 can also be prevented from dissolving.

Next, a third embodiment shown in FIG. 9 will be described. The heat absorbing fins 34 are formed to absorb heat from the air-fuel mixture immediately after passing through the catalyst body 8 so that the amount of heat back can be easily increased.

Although the oil fan heater has been described as an example, other gas fan heaters and oil / gas water heaters may be used, and have the same effect.

[0031]

In summary, the present invention relates to a vaporization pot provided with a vaporization heater for vaporizing supplied fuel oil, premixing the vaporized gas with combustion air to supply a lean mixture having an excess amount of air, and the vaporization pot. A catalyst body that catalyzes the mixture by flowing a lean mixture from the catalyst and raises the temperature of the mixture; and a combustion chamber that performs a gas phase combustion of the mixture flowing out of the catalyst body, and further comprises a vaporization pot for the catalyst body. Since it is provided in the heat absorbing cylinder provided at the upper end, the heat of the catalyst body is heated back to the vaporization pot via the heat absorbing cylinder, so that the heat back is reliable and it is necessary to energize the vaporization heater during combustion. In addition, power saving can be achieved, and a combustion device that is low in NOx and is friendly to the environment and people can be easily provided.

[Brief description of the drawings]

FIG. 1 is a perspective view of a heater equipped with a catalytic combustion device according to one embodiment of the present invention.

FIG. 2 is a sectional view of the same.

FIG. 3 is a sectional view of the main part.

FIG. 4 is a perspective view of the catalyst body.

FIG. 5 is a plan view of the catalyst body.

FIG. 6 is an enlarged sectional view of the catalyst body.

FIG. 7 is a characteristic diagram at the time of ignition.

FIG. 8 is a sectional view of a main part showing a second embodiment of the present invention.

FIG. 9 is a sectional view of a principal part showing a third embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Evaporation pot 2 Evaporation heater 7 Heat absorption cylinder 8 Catalyst 13 Combustion chamber 33 Adjusting member 34 Heat absorption fin

Claims (4)

[Claims] 1. A vaporization pot which is provided with a vaporization heater, vaporizes supplied fuel oil, and premixes the vaporized gas with combustion air to supply a lean air-fuel mixture with an excess amount of air, and a lean air-fuel mixture from the vaporization pot. And a combustion chamber for performing a gas phase combustion of the mixture flowing out of the catalyst body by catalyzing the mixture and raising the temperature of the air-fuel mixture by flowing the catalyst. A catalytic combustion device provided in a heat absorbing cylinder. 2. The catalytic combustion device according to claim 1, wherein said heat absorbing cylinder is formed integrally with a vaporization pot. 3. The catalytic combustion device according to claim 1, wherein an adjusting member for adjusting a heat back amount is provided between the heat absorbing cylinder and the catalyst body. 4. The catalytic combustion device according to claim 3, wherein heat absorbing fins projecting above the catalyst body are provided at an upper end of the adjusting member.