JPH10169914A - Catalyst combustion device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a catalyst combustion device which can reduce the generation of NOx while having an extremely simple construction. SOLUTION: A catalyst combustion device is provided with a catalyst body 7 which communicates with a vaporizing pot 1. A combustion chamber 17 is disposed above the catalyst 7 and such a combustion chamber 17 is made of a thermal insulation material 18 which has an inversed U-shaped longitudinal cross section. Furthermore, a communication passage 19 for a combustion gas which communicates with the combustion chamber 17 is formed around the outer periphery of the catalyst 7. Due to such a construction, The catalyst 7 efficiently undergoes heat exchange with the combustion gas so that the temperature of the catalyst 7 is constantly held above the activation temperature. Accordingly, a lean mixture gas which generates the least NOx can be burnt easily.

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]

In this conventional apparatus, it is necessary to keep the pre-heater 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 relates to an industrial gas turbine, and it is difficult to apply it to a small household heater or the like because it is very difficult. NOx is generated if the concentration of
The generation of NOx cannot be reliably suppressed.

[0005]

In order to solve the above-mentioned drawbacks, the present invention focuses on this point. In particular, the present invention comprises a mixture supply means for supplying a lean mixture with an excessive amount of air, and a mixture supply means. A catalyst body for catalyzing combustion by flowing a lean mixture from the means to raise the temperature of the mixture, and a combustion chamber for performing gas phase combustion of the mixture flowing out of the catalyst body, The combustion chamber is formed of a heat insulating material having an inverted U-shape in vertical cross section that covers the upper part of the catalyst body, and has a flow passage through which combustion gas after gas phase combustion flows outside the catalyst body.

[0006]

A fuel oil, which is a fuel, is sprayed into a vaporization pot 1 constituting a mixture supply means heated to a vaporizable temperature by a vaporization heater 2, and combustion air having an air ratio of about 2 is supplied. Premix to form a lean mixture with excess air.

[0007] The lean mixture flows into a honeycomb-shaped catalyst body 7 communicated above the vaporization pot 1, and is heated by the heat generated by reacting on the catalyst 12 formed on the support 10. Due to heat exchange with 7, the lean mixture further raises this temperature.

Next, the lean air-fuel mixture flows out of the catalyst body 7 and flows into the combustion chamber 17 which covers the upper part of the catalyst body 7, where it is ignited by an appropriate ignition means so that it can be burned at a high temperature. The lean mixture performs gas phase combustion.

Further, the combustion gas after the gas phase combustion once rises along the inner wall of the combustion chamber 17 having an inverted U-shape in vertical section, and then is discharged to the outside of the apparatus through the flow passage 19 outside the catalyst body 7 to be discharged into the chamber. The heating is performed.

Therefore, the catalyst body 7 can obtain a good heat-back due to the flow of the combustion gas, can easily maintain the catalyst at the activation temperature, and have the vaporization pot 1
Also, since heat can be obtained from the combustion gas, energization of the vaporization heater 2 can be stopped during combustion, and power can be saved.

[0011] Further, since the gaseous combustion of a lean mixture is used, the NOx value in the combustion gas is extremely small, and it is possible to provide, for the first time, a small-sized household heater that has little effect on the environment and is friendly to humans and has low pollution. Things.

[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.

Reference numeral 7 denotes a cylindrical catalyst body provided so as to close the upper end opening of the vaporization pot 1. A protection layer 9 made of an alumina-based heat-resistant material having a heat-resistant steel plate 8 on the outside is provided on the entire side wall. -The amount of feedback is adjusted, and here, it is 10 mm.

The catalyst 7 has a washcoat layer 11 formed on one side of a support 10 made of a corrugated metal sheet, on which palladium, platinum or (mainly composed of palladium or platinum) is formed. Selected from silver, gold, platinum, palladium, ruthenium, rhodium, or iridium,
After coating and calcining a catalyst 12 containing one or more auxiliary catalysts, the support 10 is spirally wound up and housed in a metal tube 13 to form a honeycomb shape.
When the catalyst 12 is activated, catalytic combustion, which is a chemical reaction, is performed by the flow of the air-fuel mixture.

Numeral 14 denotes a combustion cylinder surrounding the catalyst body 7 projecting above the partition plate 16 in the main body frame 15. An alumina heat-resistant material which hangs downward from the upper portion and covers the upper part of the catalyst body 7 to form the combustion chamber 17. A heat insulating material 18 having a vertical U-shaped vertical cross section,
In the combustion chamber 17, flame combustion occurs at the time of ignition, and gas phase combustion is performed after the temperature of the catalyst body 7 reaches the activation temperature.

Numeral 19 denotes a flow passage through which the combustion gas after combustion in the combustion chamber 17 flows, from the side wall of the catalyst body 7 protruding into the combustion chamber 17, passing below the heat insulating material 18 and the heat insulating material 18 and the combustion cylinder 14. Is formed so as to increase the distance between the inner wall of the combustion cylinder and the combustion gas from the discharge hole 20 at the upper end of the combustion cylinder 14.

Numeral 21 denotes a convection fan provided on the back side of the main body frame 15 behind the combustion cylinder 14, and the combustion gas discharged from the upper end of the combustion cylinder 14 is supplied to the hot air from an air outlet 22 provided below the front surface of the main body frame 15 together with the room air. And the room is heated with hot air.

Reference numeral 23 denotes a heat shield plate that partitions a space between a partition frame 24 from the upper end of the combustion cylinder 14 to the outlet 22 into a hot air path 25 through which the convection fan 21 blows air and a cooling path 26 through which cooling air flows. is there.

Reference numeral 27 denotes a heating ring located in the middle of the flow passage 19, which stands from the upper end of the vaporization pot 1 to recover heat from the combustion gas and heats it back to the vaporization pot 1.

Reference numeral 28 denotes a frame rod which penetrates the heat insulating material 18 and is provided in the combustion chamber 17. The flame rod and the gas phase combustion are applied with a voltage between the catalyst rod 7 and the flame rod and detected by the value of the current flowing through the flame rod. Is what you do.

Reference numeral 29 denotes a packing material for hermetically sealing the lower portion of the combustion tube 14, reference numeral 30 denotes a fan cover of the convection fan 21, and reference numeral 31 denotes a burner cover of the vaporization pot 1.

Reference numeral 32 denotes an operation unit provided on the upper part of the main body frame 15, and 33 denotes a cartridge tank (not shown) for the main body frame 1.
5 is a tank lid for taking in and out of 5, 5 is a handle, and 35 is 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 7 has not been heated yet and is at room temperature. 7, the fuel is ignited by a suitable ignition means in the combustion chamber 17, and as shown in FIG. 7, normal flame combustion is performed at the time of ignition, and this flame combustion is maximum thermal combustion.

When the catalyst body 7 is heated by the flame combustion and becomes over 250 ° C. of the activation temperature of the catalyst, this is detected by a temperature sensor, operation, timer count from the ignition, or the like, and the fuel oil amount is reduced. It is set so that the outgoing air ratio is close to 2.

As a result, a lean mixture is formed in the vaporization pot 1 and flows into the catalyst body 7 which has reached the activation temperature, so that the catalyst 12 reacts the fuel and air in the catalyst body 7. 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 rapidly rises to 800 to 900 ° C. in the catalyst body 7, and the transient state of FIG. After that, the fuel is ignited by a self-ignition phenomenon in the combustion chamber 17 to perform gas phase combustion at 1200 to 1500 ° C.

Therefore, the combustion gas after the combustion is supplied to the flow passage 1
9 is discharged from the upper part of the combustion tube 14 to the convection fan 21.
The air is blown as warm air from the outlet 22 to heat the room. However, since the heating is performed by combustion of a lean mixture, the NOx value is 1 to 20 ppm. NOx value of 110 to 120 pp
The value is extremely low with respect to m, and it is possible to realize a low-pollution heater with little effect on the environment and people.

On the other hand, the combustion gas after the gaseous phase combustion in the combustion chamber 17 flows through the flow passage 19, passes through the outer peripheral side wall of the catalyst body 7, and heats back via the protective layer 9, so that the catalyst body 7 is always The heating temperature is maintained at the activation temperature, and the heating ring 27 protruding into the flow passage 19 can also obtain the heat back of the combustion gas in the vaporization pot 1, and during the combustion, the energization of the vaporization heater 2 is almost stopped. Is what you do.

Therefore, the combustion chamber 17 made of the heat insulating material 18 having an inverted U-shape in vertical section and the flow passage 19 communicating therewith,
Heat-back to the catalyst 7 and the vaporization pot 1 is performed well, unnecessary power and complicated control are not required, the catalyst 7 can be easily maintained at the activation temperature, and the above-mentioned NO is hardly burned.
The combustion of a lean mixture having a small x value can be continued without difficulty.

Further, the catalyst 7 is a catalyst 12 containing palladium as a main component.
Is applied, heat is dissipated by heat conduction from the wall surface of the support 10 having the catalyst 12 to the wall surface having no catalyst 12 and through which only the air-fuel mixture flows.
~ 950 ° C, and there is no fear of melting or misfiring due to temperature rise, and good catalytic combustion can always be obtained.

By projecting the upper end of the catalyst 7 into the combustion chamber 17, the lower end of the heat insulating material 18 becomes lower than the catalyst 7,
The combustion gas can surely come into contact with the outer periphery of the catalyst body 7, and a good heat back can be obtained.

[0031]

In short, the present invention provides a mixture supply means for supplying a lean mixture having an excess amount of air, and a catalytic combustion by flowing the lean mixture from the mixture supply means to raise the temperature of the mixture. And a combustion chamber for gas-phase combustion of an air-fuel mixture flowing out of the catalyst body, wherein the combustion chamber is formed of a heat insulating material having an inverted U-shaped vertical cross section that covers the upper part of the catalyst body. Since the flow path through which the combustion gas after the gas phase combustion flows is provided outside the catalyst body, the catalyst body can always be maintained at the activation temperature by the heat-back from the combustion gas. It is possible to obtain good combustion with little generation of NOx, and to provide a combustor that is friendly to the environment and humans with only an extremely simple configuration, without requiring any components, circuits, or configurations.

[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.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 vaporization pot 2 vaporization heater 7 catalyst 10 support 12 catalyst 17 combustion chamber 18 heat insulating material 19 flow passage

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Yoshiji Tokita 7-7 Higashi Shinbo, Sanjo-shi, Niigata Prefecture Inside (72) Inventor Katsumi Moruga 7-7 Higashi-Shinbo, Sanjo-shi, Niigata Prefecture Corona Co., Ltd. (72) Inventor Kazuhiro Takeda 7-7 Higashi Shinbo, Sanjo, Niigata Prefecture Corona Co., Ltd. (72) Inventor Masaki Takachi 7-7 Higashi Shinbo, Sanjo City, Niigata Prefecture Corona Co., Ltd. (72) Inventor Tohru Shoji 2-73, Shinmachi, Hiratsuka-shi, Kanagawa Prefecture Inside the Technology Development Center, Tanaka Kikinzoku Kogyo Co., Ltd. Tetsuya Unno 2-73 Shinmachi, Hiratsuka-shi, Kanagawa Prefecture Tanaka Kikinzoku Kogyo Co., Ltd. Technology Development Center

Claims (5)

[Claims] An air-fuel mixture supply means for supplying a lean air-fuel mixture with an excess amount of air, a catalyst body for catalyzing combustion by flowing the lean air-fuel mixture from the air-fuel mixture supply means to raise the temperature of the air-fuel mixture, A combustion chamber for gas-phase combustion of an air-fuel mixture flowing out of the catalyst body, wherein the combustion chamber is formed of a heat insulating material having an inverted U-shape in vertical section covering the upper part of the catalyst body, and provided outside the catalyst body. A catalytic combustion device comprising a flow passage through which combustion gas after gas phase combustion flows. 2. The catalytic combustion according to claim 1, wherein said mixture supply means comprises a vaporization pot having a vaporization heater and forming a premixture of vaporized gas and combustion air inside. apparatus. 3. The catalytic combustion apparatus according to claim 1, wherein said catalyst body is constituted by a catalyst body having a self-temperature control function of maintaining a catalyst temperature at a constant temperature. 4. The catalytic combustion apparatus according to claim 1, wherein said catalyst body has a tip portion projected into a combustion chamber. 5. The catalytic combustion apparatus according to claim 1, wherein said catalyst body is covered with a protective layer on the entire side wall.