JPS59153017A - Catalytic burner - Google Patents

Abstract

PURPOSE:To obtain oxidation reaction which is stable and having favorable efficiency even under wide range of air-fuel ratio, by so constituting the title burner that a honeycomb type flame hole plate is made to touch a spouting plate having a large number of spouting holes. CONSTITUTION:A spouting plate 12 having a large number of spouting small holes 11 is arranged in front of an evaporating premixing cylinder 7 so that the spouting plate 12 and the evaporating premixing cylinder 7 are formed in unified structure with which a cylindrical combustion cylinder 13 made of a heat resisting metal is connected further. As for the inside of the combustion cylinder 13 a honeycomb type flame hole plate 14 made of heatproof ceramics is provided toward the upper part of the combustin cylinder 13 so that the flame hole plate 14 is abutted against the top of the spouting plate 12, and cylindrical catalytic bodies 15 are arranged in order further above the flame plate 14. With this construction, it becomes that premixed air-fuel mixture spouting from the spouting small hole forms a stable flame on the honeycomb type flame hole plate, and heats the backside of the catalitic body evenly, which results in possibility of performing stable combustion even under a wide range of an air- fuel ratio.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is applicable to various gaseous fuels or vaporized liquids 21:
- This invention relates to a catalytic combustor that supplies di-fuel together with combustion air onto a catalyst body, causes an oxidation reaction to occur on the surface of the catalyst body, causes the catalyst body to generate heat, and utilizes the generated heat.

Structure of the conventional example and its problems As shown in Fig. 1, the structure of the conventional catalytic combustor includes a honeycomb-shaped cylindrical catalyst body A2 in a cylindrical combustion cylinder A1, and a disk-shaped rectifier. It was just the installation of board A3. In this method, when flameless combustion is performed on the catalyst body A2, as the excess air ratio is decreased, the catalyst body A2 no longer burns.
2, flameless combustion did not occur and a flame was formed on the rectifying plate A3, which caused abnormal heating of the rectifying plate A3, and the flame was dangerously transferred to the rear of the rectifying plate A3. Therefore, with this structure, stable combustion could not be achieved over a wide range of air-fuel ratios.

On the other hand, even in a structure that uses flame, as shown in Figure 2, the flame hole plate B6 is simply installed behind the catalyst body B4, and the flame hole plate B5 is prevented from being abnormally heated by the flame. In order to achieve this, it was necessary to make the holes in the flame hole plate B6 smaller to increase the jet velocity and to float the flame from the flame hole plate B6. Therefore, the state of the flame becomes very unstable, and especially when the excess air ratio is increased, a high temperature area and a low temperature area are distributed on the back surface of the catalyst body B4, and unburned gas such as Co is discharged from the low temperature area. As a result, stable combustion over a wide range of air-fuel ratios was not possible.

OBJECTS OF THE INVENTION The present invention solves the conventional gap, and provides a catalytic combustor that allows stable and efficient oxidation reaction even under a wide range of air-fuel ratios and produces clean exhaust gas. The purpose is to

Structure of the Invention In order to achieve this object, the present invention includes a jetting plate provided with a large number of jetting holes for spouting the premixed air on the upstream side of the premixed air flow, and a no-nicum type flame hole plate on the downstream side. The basic configuration is that the catalyst body is installed so as to be in contact with the ejection plate, and a catalyst body is installed with a space left on the downstream side. With this configuration, the premixed gas ejected from the ejection holes of the ejection plate is rectified by energizing the cells of the honeycomb flame hole plate to form a stable flame near the outlet of the honeycomb flame hole plate. Furthermore, the catalyst body is uniformly heated by the radiant heat of the stable flame, and reaches the activation temperature.

On the other hand, unburned gas that has not been completely combusted by flame combustion is further oxidized on the catalyst body that maintains the activation temperature.
It is emitted as clean exhaust gas. Therefore, even if the excess air ratio is high and the jet is strongly ejected from the ejection plate, the flame is rectified while passing through the cells of the honeycomb flame hole plate and a stable flame is formed. As a result, it is possible to obtain a wide combustion range.

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a catalytic combustor according to the present invention is shown in FIG. 3 and will now be described.

A resistance plate 8 made of wire mesh or punching metal is installed inside the vaporization premixing cylinder 7 in which the sheathed heater 6 is embedded, and a fixed plate 1 having an air port 9 in the center is installed behind the vaporization premixing cylinder 7.
0 is joined. On the other hand, in front of the vaporization premixing cylinder 7, an ejection plate 12 having a large number of small ejection holes 1161 is installed so as to form an integral structure with the vaporization premixing cylinder 7, and a cylindrical plate made of heat-resistant metal is installed. This is due to the fact that the combustion cylinder C13 is joined. Inside the combustion tube C13, a honeycomb flame hole plate 14 made of heat-resistant ceramic is installed toward the front so as to be in contact with the front surface of the ejection plate 12, and further forward, cylindrical catalyst bodies C15 are sequentially installed. ing. Further, immediately in front of the honeycomb flame hole plate 14, a spark plug 16 is installed so as to penetrate through the combustion tube C13. On the other hand, at the tip of the shaft 17 facing into the vaporization premixing cylinder 7, there is a circular trapezoidal cone 1 whose diameter increases toward the front.
82 rotating plate 192 mixing plate 2 having small stirring blades on the peripheral edge
0 is fixed in sequence.

Further, the tip of the oil supply pipe 21 is installed so as to open to the side of the cone 18.

Next, the operation of the embodiment with the above configuration will be explained.

When the sheath heater 6 is energized and the side wall of the vaporization premix cylinder 7 reaches a predetermined temperature, the fan and electromagnetic pump (both not shown) are energized and the supply of air and liquid fuel is started. The liquid fuel is sent onto the rotating cone 18 through the fuel supply pipe 216, and when it reaches the rotating plate 19 along the taper of the cone 18, it is dispersed as fine particles in the circumferential direction by the rotational force, and is vaporized and premixed at a constant temperature. It collides with the side wall of cylinder 7 and immediately vaporizes. On the other hand, the air taken in by the fan is sent into the vaporization premix cylinder 7 through the air port 9, and is uniformly mixed with vaporized liquid fuel by the mixing plate 20 to become a premix gas. The premixed gas is passed through the resistance plate 8° and the ejection plate 12. After passing through the honeycomb flame hole plate 14, the spark plug 16 emits a spark when energized.
is ignited. The flame generated by ignition is rectified by the premixed gas passing through the cells of the honeycomb flame hole plate 14, so that the flame remains stable. In this state, the catalyst body 016 reaches the activation temperature by receiving radiant heat from the flame and heat transfer from the combustion tube C13. At this point, the premixed gas that has not been completely combusted by flame combustion is completely oxidized on the catalyst C15, which maintains the activation temperature, and is discharged as clean exhaust gas. In addition, even if the excess air ratio is increased, the flame is stabilized immediately above the honeycomb flame hole plate 14 because it receives a rectifying effect within the cell 7 nopa of the honeycomb flame hole plate 14, resulting in a stable combustion state. keep it. Therefore, extreme distribution of high-temperature and low-temperature regions does not occur on the back surface of the catalyst body C15, and a uniform temperature state is maintained, thereby maintaining a stable oxidation state.

As data to demonstrate the effects of the catalytic combustor of the present invention, Fig. 4 shows the difference in combustion characteristics when using the conventional example shown in Fig. 3 and the inventive example shown in Fig. 3. In addition, the catalyst body B4. The catalyst C16 used ZrO2 as a carrier and supported a large amount of N1 as an oxidation catalyst, and kerosene was used as the fuel.

In the figure, the definitions of combustion upper limit and combustion lower limit indicate the limit C○2 concentration at which Co starts to occur in the exhaust gas when the excess air ratio is decreased and increased, respectively.・The combustion shown in Figure 4 The characteristic diagram shows that in the case of the conventional example, the combustion lower limit is particularly high in the low combustion amount region, that is, a stable combustion state cannot be obtained when the excess air ratio is increased. On the other hand, in the case of the example of the present invention, the combustion range is wider than that of the conventional example in the entire range of combustion amount measured.

Effects of the Invention In view of the above, the catalytic combustor of the present invention provides the following effects.

(1) Since the honeycomb flame hole plate is in contact with the jet plate having a large number of small jet holes, the premixed gas ejected from the jet holes is rectified by passing through the cells of the honeycomb flame hole plate. A stable flame is formed on the honeycomb flame hole plate.

(2)... Due to the stable flame from the Nikam flame hole plate,
Since the back surface of the catalyst body is heated uniformly, even if the excess air ratio is increased, there will be no distribution of extremely high temperature and low temperature areas.
As a result, stable combustion can be achieved even under a wide range of air-fuel ratios.

[Brief explanation of drawings]

Figure 1 is a vertical cross-sectional view of the main parts of a conventional flameless catalytic combustor;
The figure is a longitudinal sectional view of a conventional flame-combined catalytic combustor, FIG. 3 is a longitudinal sectional view of an embodiment of a catalytic combustor according to the present invention, and FIG. 4 is a longitudinal sectional view of a conventional example and an embodiment of the present invention. FIG. 2 is a comparison diagram of the combustion characteristics of 91-2 11... small ejection hole, 12... ejection hole, 1
4...Honeycomb flame hole plate, 16...Catalyst body C6 Name of agent Patent attorney Toshio Nakao and one other person See Figure 3 Figure 4

Claims (3)

[Claims] (1) On the upstream side of the fuel-air premixed air flow, a blowout plate having a large number of blowholes for blowing out the premixed air is provided, and on the downstream side, a nicum type flame hole plate for forming a flame is provided as described above. A catalytic combustor is installed so that it is in contact with the ejection plate, and a space is provided on the downstream side where a catalyst body is installed. (2) The catalytic combustor according to claim 1, wherein the porosity of the ejection plate is smaller than that of the honeycomb flame hole plate. (3) The catalytic combustor according to claim 1, wherein a heat-resistant ceramic such as alumina, mullite, mullite-zircon, or zirconia is used as the material of the carrier and the honeycomb flame hole plate.