JPS61246512A - Burner - Google Patents

Abstract

PURPOSE:To increase the amount of combustion per unit area and make it possible to perform a high load combustion by providing a cooling passage at least at one of the internal section and outer periphery of a catalyst body. CONSTITUTION:There are provided an internal cooling passage which is formed cylindrically with iron, stainless steel, etc. and one end of which is connected to the outlet opening of a cooling blower 13 via an external cooling passage, and the other end of which penetrates a catalyst body 6, and an external cooling passage 15 which surrounds the internal wall 12 in order to cool its outer periphery and which is partially formed with a wall made of glass, etc., which is connected to the outlet opening of the blower 13. Since the internal cooling passage 14 which penetrates the inner section of the catalyst body 6 receives the heat radiated from the catalyst body 6 over the whole of the passage, the temperature of the catalyst body 6 is difficult to rise, and the inner wall 12 which is cooled by the external cooling passage 15 also prevents the temperature rise in the catalyst body 6.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an apparatus for burning liquid or gaseous fuel, and is used as a heating heat source for heating, drying, hot water supply, etc.

Prior Art A conventional catalytic combustion apparatus is shown in FIG. In FIG. 3, reference numeral 1 denotes a catalyst body having a large number of combustion holes 2. The mixture of fuel gas and air enters the premixing chamber 4 through the premixing pipe 3 and is combusted in the combustion hole 2 described above. The catalyst body 1 reaches a high temperature due to the combustion reaction, and the heat is radiated through the glass 5f provided on the outer periphery. Furthermore, exhaust gas is discharged downstream of the catalyst body 1.

Further, a preheating ignition heater 6 is provided upstream of the catalyst body 1.

Problems to be Solved by the Invention However, with such a configuration, it is difficult to perform high-load combustion.
There were drawbacks that led to The reason for this is explained below. When a large amount of fuel gas is burned in the catalyst body 1 having a limited area, the temperature of the catalyst body 1 increases in accordance with the amount of combustion. As a result of this high temperature, (1) the catalyst deteriorates in terms of its lifespan.

(2) The premixed gas in the premixture chamber 3 is ignited. 2
Therefore, there is a limit to the amount of combustion per unit area. In order to prevent such problems, the temperature of the catalyst body 1 can be prevented by using glass 6f, a thin material with good heat permeability, or the catalyst body 1 can be made of a platinum group catalyst [-- fully supported on the catalyst body 1]. Conventionally, measures have been taken to suppress ignition of the premixed gas.

The present invention further fundamentally solves these problems, increases the amount of combustion per unit area, and enables high-load combustion with a more compact catalyst body.

An elaborate means for solving the problems and a technical means of the present invention for solving the above problems is to provide a cooling path in at least one of the inside and the outer periphery of the catalyst body.

action The effect of this technical means is as follows.

That is, the outer circumference of the catalyst body is cooled by the fluid that cools the outer circumference of the catalyst body, and the temperature of the inside of the catalyst body is lowered by the fluid passing through the inside. Since the temperature of the catalyst as a whole becomes low, catalyst life deterioration 9 and ignition as described above are less likely to occur. Of course, if the temperature is too low, the catalyst becomes inactive and complete combustion occurs, so the amount of cooling fluid is set to maintain a predetermined temperature.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to FIG. 6
The catalyst body is made of heat-resistant materials such as alumina, silica, and calcia. The catalyst body 1 is provided with a large number of combustion holes 7. Upstream of the premixing pipe 8, an air and fuel gas supply section (not shown) is provided.

The mixed gas that enters the premix chamber 9 from the premix pipe 8 is combusted by a platinum group catalyst supported on the surface of the catalyst body 60. Further, in order to sufficiently carry out such a catalytic reaction, the catalytic body 6 is heated in advance to a predetermined temperature by a heater 10. In the above-mentioned configuration, the present invention includes a cooling blower 13, and this blower 13.
One end communicates with the discharge port of the catalytic converter via the next external cooling path, and the other end cools the internal cooling path 14 formed in a cylindrical shape made of iron or stainless steel or the like that passes through the catalyst body 6t, and the outer periphery of the inner wall 12. An external cooling path 15 is provided, which is formed of a wall made of glass or the like, which surrounds the inner wall 12 and is partially connected to the outlet of the blower 13. The effects of these two cooling paths will be described below.

The premixed gas starts to burn from the upstream side of the catalyst body 6 and completes its reaction in the combustion hole 7 while reaching the downstream side. A feature of such catalytic combustion is that since a large proportion of the combustion heat heats the catalyst body 6, the temperature of the catalyst body 6 tends to increase. Therefore, the small size of the medium 6
As mentioned above, there is a limit to increasing the combustion rate.

The heat of the catalyst body 6 is dissipated by radiation, but if glass is used for the inner wall of the premixture chamber 9 as in the past, the heat cannot be sufficiently radiated. because,
Most of the heat does not pass through glass; it is absorbed by the glass itself.
This is because the glass becomes hot. Since the heated glass does not sufficiently absorb the heat of the catalyst, the heat dissipation of the catalyst is insufficient and the temperature easily rises.

However, in the configuration of the present invention, the internal cooling path 14 penetrating the inside of the catalyst body 6 receives the heat radiated by the catalyst body 6 throughout the path, so that the temperature of the catalyst body 6 is difficult to rise. The inner wall 12 cooled by the catalyst member 15 also prevents the temperature of the catalyst body 6 from rising. Of course, in this case, the catalyst body 6 is heated by heat conduction through the heat insulating material 11 interposed between the catalyst body 6, the inner wall 12, and the internal cooling path 14.
However, this cooling by heat conduction is not preferable because it causes only the contact portion to be at a low temperature and causes temperature non-uniformity in the catalyst body 6.

Asbestos ceramic fibers and mineral fibers are selected as heat insulating materials for this purpose. That is, the present invention aims at uniformly lowering the temperature of the catalyst surface by cooling by radiation, and since the cooling by heat transfer is localized, the internal cooling path 14 and the catalyst body 6 are insulated. Further, in the above embodiment, cooling is performed from both the outside and the inside, but if the size of the catalyst body 6 is small, either one may be used. When the size of the catalyst body 6 is wide, temperature unevenness occurs due to the difference in distance between each part of the catalyst body 6 and the cooling path, resulting in a partial increase in temperature. In this case, internal cooling paths may be provided and the number thereof may be arbitrarily selected.

Next, the second claim will be explained.

The inner wall 12 that receives the heat of the catalyst body 6 and the heat-receiving surface of the internal cooling path 14, that is, the portion facing the catalyst body 6, are subjected to heat absorption treatment. Heat absorption treatments include sandblasting and oxide coating on metals.

It is coated with black paint, thermal spraying, etc. to obtain a surface with better heat absorption than metal materials. If the absorption rate (also called emissivity) is low, heat will be reflected and the catalyst body 6 will have a high temperature. By adding the second aspect of the invention, even if the amount of combustion per unit area is increased, ignition or high-temperature deterioration of the catalyst can be prevented.

Next, claim 3 will be explained with reference to FIG. 2. It should be noted that the same parts as in the above embodiment are given the same numbers and the explanation thereof will be omitted, and the explanation will focus on the different parts.

Heat radiation part of inner wall 12 of premixture chamber 9 and internal cooling path 1
A large number of heat radiating fins 16 are provided on the heat radiating portion of No. 4, that is, on the cooling fluid side of both. catalyst body 6 and inner wall 12,
Alternatively, as the temperature difference in the internal cooling path 14 increases, the amount of radiation from the catalyst body 6 increases and the temperature decreases. For this purpose, fins are provided on both heat dissipation parts. By adding this invention, the effects of the present invention will be further enhanced.

Next, Claim 4 will be explained.

It is well known that platinum group metals such as platinum and baradium are extremely active as combustion catalysts that have the effect of suppressing ignition when supported as a catalyst. However, it not only actively performs oxidation reactions, but also has the function of suppressing ignition.

That is, although a flammable air-fuel mixture is supplied to the premixture chamber 9, if the temperature of the medium catalyst 6 becomes high, the above-mentioned air-fuel mixture will ignite. However, in this case, even if the catalyst reaches the ignition temperature of the air-fuel mixture, it will not ignite. This strange phenomenon occurs because the air-fuel mixture is flowing toward the catalyst body 6, so the temperature of the air-fuel mixture itself is not high. However, in this case as well, the extremely thin layer of the air-fuel mixture in contact with the catalyst body 6 appears to have reached its ignition temperature. Since this layer is microscopically small, it does not grow as a flame, so the flame does not spread throughout the premixture chamber 9 as ignition occurs.

However, if the catalyst body 6 becomes extremely hot, this microscopic layer will also become thick, and the premixture chamber 9 will catch fire.

In order to suppress this phenomenon, it is necessary to take measures to lower the temperature of the catalyst body 6, but if a platinum group metal is used as the catalyst, it has a great function of suppressing ignition even at high temperatures. The reason for this phenomenon is that platinum group catalysts have extremely strong reactions and form a reaction zone very close to the platinum, so even if the flame grows, it is difficult for it to touch the platinum and grow. If such a platinum group catalyst is used, the amount of combustion can be increased and the temperature can be increased to the extent that ignition is suppressed.

The effects of the invention can be reduced, thereby making it possible to create a compact combustion device with a large calorific value. This combustion device also maintains cleanliness such as low NOx, which is an inherent characteristic of catalytic combustion. Furthermore, the darning combustion device can be used for heating by using air as the fluid in the cooling path mentioned above, or for hot water supply by using water, and also functions as a heat exchanger. There is also something to be gained.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of one embodiment of the present invention, FIG. 2 is a cross-sectional view of another embodiment of the present invention, and FIG. 3 is a cross-sectional view of a conventional combustion apparatus. 6...Catalyst body, 11...mark/insulating material, 14...
... Internal cooling path, 16... External cooling path, radiating fin for 16.... Name of agent: Patent attorney Toshio Nakao (1st person)
Figure 14...Bo @Suzuoka Section K...Outside #Oiketai 2nd Figure 6...Touch-11 It//...Fr Heat Material 14...Inside @4What1ri each

Claims (4)

[Claims] (1) A catalyst body having a large number of combustion holes, a part that supplies a mixture of fuel and combustion air to the catalyst body, and a catalyst body provided on the outer periphery or inside the catalyst body via the catalyst body and a heat insulating material. A combustion device having at least one cooling path. (2) The combustion device according to claim 1, wherein the heat receiving surface facing the catalyst surface of the cooling path is subjected to radiation absorbing surface treatment. (3) The combustion device according to claim 1, wherein a heat radiation fin is provided on the heat radiation surface in contact with the cooling fluid of the cooling path. (4) The combustion device according to claim 1, wherein the catalyst supported on the catalyst body is a platinum group catalyst.