JPS5886347A - Hot air heater - Google Patents

Abstract

PURPOSE:To perform a clean combustion operation by a method wherein a catalyst is provided right above a combustion chamber and the catalyst is covered by an air blowout guide from above the upper part thereof. CONSTITUTION:A flame hole 3 is shielded by an outer cylinder 4, a mixing pipe 5 is arranged at the lower part of the outer cylinder 4, the catalyst 6 held by a catalyst support 7 is arranged right above the combustion chamber 8 and the air blowout guide 9 is provided above the catalyst 6 so as to cover the latter. Further, primary air exceeding its theoretical quantity is mixed with a fuel within the mixing pipe 5 and the mixture is burned uniformly and superficially above the flame port 3 so that NO contained in the resultant waste combustion gas within the combustion chamber 8 is partially oxidized to becomes NO2 until it reaches the catalyst 6. In this case, most of NO2 in the waste combustion gas is reduced again to NO on the catalyst and CO in the gas is also partially oxidized. At the same time, air blow by a blower 10 flows along the air blowout guide 9 so that the air and the waste combustion gas are mixed slowly and the generation of NO as a whole in the gas is sharply reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an IJ-on combustion technology for an indoor open hot air heating system.

In recent years, along with the problem of air pollution, attention has been paid to indoor environment pollution, and clean combustion technology for indoor open combustion appliances has become important.

Among these, there is a need to reduce the indoor concentration of nitrogen oxidizers (hereinafter referred to as NOx), particularly nitrogen dioxide (hereinafter referred to as NO2). In order to suppress this indoor NO2 concentration, +
A method for suppressing NO2 by suppressing the oxidation of r+-nitric oxide (hereinafter referred to as NO) to NO2, (i!1N
A method for reducing NO2 by reducing O2 to No, +io+
Methods include decomposing NOx generated and completely suppressing GVINOX (7) generation. In the case of (1), oxidation prevention is a difficult problem because the NO2 generation mechanism has not been fully elucidated. However, according to experiments, as the degree of quenching of the combustion waste gas increases, No in the waste gas is more likely to be oxidized to NO2. Based on this fact, when we examine the mixing process of the combustion waste gas flow seen in conventional hot air heaters and the flow induced by the blower, we find that in Figure 2, the two are perpendicular to each other, and the induced It is hit by the flow of water and is rapidly cooled.
Cheap.

Further, in FIG. 3, flow entrainment tends to occur at the lower part of the catalyst 8, causing rapid cooling of the combustion waste gas. Therefore, in the conventional mixing method, a problem arises in that the oxidation ratio of NO to NO2 is high.

The present invention uses combustion technology to suppress the generation of NOx, suppresses the oxidation of NO to NO2 using a blower guide that surrounds the catalyst from above, and further converts NO2 into NO2 using the catalyst.
The purpose of the present invention is to provide a hot air heating device for home use that achieves clean combustion and solves the problems of the conventional method.

An embodiment of the present invention will be described below based on FIG. 1. Wire mesh: The flame hole 3 is covered with an outer cylinder 4, and a mixing pipe 6 is provided at the bottom of the outer cylinder. The catalyst 6 is supported on a catalyst support 7 and is located directly above the combustion chamber 8, with a blower guide 9
is surrounded from above the catalyst 6, and in this case, the lower end t;1. It is configured to be on the same level as or below the catalyst 1h1.

In the above configuration, the primary air (theoretical air) exceeding 11゛ is mixed with the fuel in the mixing tube 6 and uniform surface combustion is performed in the flame hole 3-1. NO
reaches the catalyst 6, where it is oxidized and becomes NO2. However, NO2 in the combustion waste gas is removed by the catalyst 61-.
Many of them are +Ir and No, Jlo, °1 element, and
- Carbon oxide (hereinafter referred to as (1)) is partially oxidized.

On the other hand, the l/1. Since the flow flows along the blower guide 1o, it does not get caught inside the blower guide. As a result, the combustion waste gas and the flow induced by the blower 10 mix gently and are supplied into the room from the outlet 12 as warm air.

From the above process, the following '11 pattern can be concluded.

By performing premix combustion exceeding the theoretical air amount, P
By suppressing the generation of romt No and performing uniform surface combustion, it is possible to suppress the decrease in flame temperature and the local temperature increase, and to significantly reduce the generation of No as a whole. On the other hand, on the catalyst, most of the NO2 in the combustion waste gas is converted to No, and at the same time, some of the CO is oxidized to become C02. Unless there is a flow other than combustion waste gas on the catalyst surface,
Oxidation of No to NO2 in this region is difficult to proceed without rapid cooling.

Furthermore, since it mixes slowly with the flow induced by the blower, oxidation of No to NO2 is unlikely to occur, as described above. Therefore, NO2 and N in the hot air supplied indoors
o, Go concentration (02-=Q% conversion) is extremely low and clean combustion can be achieved.

As is clear from the above description, the hot air heating device of the present invention performs premixed surface combustion with an equivalence ratio of 1.0 or less, and also provides a catalyst directly above the combustion chamber and surrounds the catalyst from above. Clean combustion can be achieved by installing a blower guide.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of the hot air heating device of the present invention, and FIGS. 21 and 3 are local sectional views of a conventional Yμ air heating device. 3...flame hole, 4...outer cylinder, 6...
...Mixing tube, 6...Catalyst, 7...Catalyst body, 8...Combustion chamber, 9...Blower guide, 10... ·Blower.

Claims (1)

[Claims] A hot air heating device in which a catalyst supported by a catalyst support is provided directly above a combustion chamber of an indoor open type combustion device, and an air blowing guide is provided to surround the catalyst from above.