JPH0221117A - Catalyst combustion burner - Google Patents

Abstract

PURPOSE:To make it possible to obtain concentrated catalyst combustion effect, improve strength and compact its size by constituting a catalyst which adopts alumina whiskers as its carrier on the surface of a mother material comprising Fe-Cr-Al stainless steel. CONSTITUTION:A mother material 2 of a catalyzer 1 for a burner is composed of Fe-Cr-Al stainless steel is subjected to high temperature oxidation treatment ranging from 850 to 1,000 deg.C under oxidizing atmosphere, thereby forming alumina whiskers 4 whose length exceeds 0.1mum on the surface. Furthermore, the surfaces 2a of the alumina whiskers 4 and the mother material 2 are arranged to carry a catalyst 5 or an active substance designed to burn gases which contain methane gas to a large extent, such as natural gas without producing flames and at a low temperature around 600 deg.C. In this manner, catalyst combustion is carried out effectively. Furthermore, the mother material is composed of Fe-Cr-Al stainless steel, which improves its strength. Infrared radiation energy produced by a catalyst combustion and whiskers are dramatically increased so that heating effect may be improved, thereby enabling a catalyst combustion burner to be reduced in size as well.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a catalytic combustion burner, and more particularly:
The present invention relates to a catalytic combustion burner that supplies fuel F1 residue onto a catalyst body, catalytically oxidizes the fuel F1 with combustion air or oxygen, and utilizes the combustion heat and radiant heat generated by the reaction.

Prior Art A typical prior art is disclosed in Japanese Patent Application Laid-Open No. 51-83088. This prior art uses a catalyst body having a structure in which a catalytically active substance is supported on an inorganic fiber carrier such as silica or alumina.

Problems to be Solved by the Invention In such prior art, since the carrier is made of inorganic fibers, (a) the strength of the carrier is insufficient, and (b) in order to improve the overall strength, it is necessary to Reinforcing members must be placed, which increases the thickness,
(C) There are problems such as deterioration of the inorganic fibers used as the carrier, and (d) It is difficult to manufacture shapes other than planar.

The purpose of the present invention is to solve the problems of the prior art, and is to provide a product that has high strength, can be made thin and compact, can be used for a long period of time, and can be processed into various shapes. It is an object of the present invention to provide a catalytic combustion burner that can perform the following steps.

Means for Solving the Problems The present invention has alumina whiskers produced by oxidation treatment on the surface of a base material made of Fe-Cr-Al stainless steel, and supports a catalyst on the alumina whiskers to form a catalyst body. This is a catalytic combustion burner characterized by comprising a catalyst body and combusting fuel gas using this catalyst body.

Function According to the present invention, the base material made of Fe-Cr-Al stainless steel has alumina whiskers on its surface, and the catalyst is supported on the alumina whiskers to form a catalyst body.
The surface layer created by the alumina whiskers provides an intensive catalytic combustion effect and also prevents backfire.

This base material is made of stainless steel as described above, and has improved strength, and therefore can be made thinner and smaller.

Furthermore, corrosion resistance and durability can be improved by the action of this alumina whisker. Furthermore, this catalyst body can be made into various desired shapes, and effective heating can be performed with the shape suitable for the object to be heated.

Further, according to the present invention, far infrared rays are efficiently radiated by both the catalytic combustion and the alumina whiskers, and the radiant energy is significantly increased.

Embodiment FIG. 1 is a cross-sectional view of a catalyst body 1 according to an embodiment of the present invention.
FIG. 2 is a plan view of the catalyst body 1.

Using this catalyst body 1, a catalytic combustion burner is constructed as shown in FIG. 4, which will be described later. A plurality of through holes 3 are formed in the base material 2 of the catalyst body 1 . This base material 2 is Fe-Cr-A
f It is made of stainless steel, its components are limited as follows, and it has the following surface properties.

Cr: Cr is an essential element for stainless steel, and if it is less than 12% by weight, corrosion resistance and oxidation resistance are lost. Furthermore, if Cr exceeds 28% by weight, the steel becomes brittle and cannot be processed into a radiator, so it is limited to 122 weight % or more and 28 weight % or less.

If AI is less than 1.0% by weight, the oxide film formed by high-temperature oxidation treatment will consist mainly of Fe and Cr oxides, no alumina whiskers will be generated, and corrosion resistance will be lost. The more AI there is, the more the object of the present invention can be achieved, but if it exceeds 8.0% by weight, the steel becomes brittle and it becomes difficult to manufacture steel sheets. Limited to % by weight or less.

Next, high-temperature oxidation treatment is performed by holding the temperature at 850 to 1000°C for more than 1 hour in an oxidizing atmosphere such as the air, so that the surface has a length of 0.
Alumina whiskers of 1 μm or more are formed.

This high temperature oxidation treatment temperature is less than 850°C or 1000°C.
When the temperature exceeds 850°C and 1000°C or less, no alumina whiskers are formed and the oxide film becomes smooth alumina, making it impossible to obtain far-infrared radiation characteristics. Furthermore, the processing time is 1 hour or more. If the oxidation treatment is carried out for less than 1 hour, the length of the alumina whiskers will not become 0.1 μm or more, so the oxidation treatment is carried out for 1 hour or more.

However, if the Al content of the steel sheet is less than 3% by weight, the length of the alumina whiskers may be short and the density may be low if only high-temperature oxidation treatment is performed. At this time, as a preliminary oxidation treatment,
700-1000℃ in an atmosphere with an oxygen concentration of 0.1% or less
When heat-treated for 10 seconds or more, a high-purity alumina oxide film with a thickness of less than 1000 is formed on the surface of the steel sheet, and when the high-temperature oxidation treatment is performed next, alumina whiskers are likely to be generated.

In the above preliminary oxidation treatment, the oxygen concentration in the atmosphere is 0.
．． If it exceeds 1%, Fe and Cr will be mixed into the oxide film and alumina whiskers will not be formed, so the content should be 0.1% or less. In addition, if the temperature is lower than 700℃ or for less than 10 seconds, the oxide film formed is too thin to be effective, and if the temperature exceeds 1000℃, the crystal grains of the steel plate become coarse and brittle, making it impossible to process. Limited to seconds or more.

Component C of Fe-Cr-Al stainless steel used in the present invention
, Si, and Mn are determined as follows.

C: C deteriorates the toughness and ductility of the base metal and weld.

Therefore, in the process of manufacturing the material of the present invention, plate breaks, edge cracks, and bending cracks occur, which significantly impairs productivity. Therefore, C is limited to 0.03% by weight or less.

Si: Although Si improves high-temperature oxidation resistance, it significantly impairs the ductility of the base metal and weld, so it is limited to 1.0% by weight or less.

Mn: Mn deteriorates the toughness of the base metal and the weld zone and impairs oxidation resistance at high temperatures, so it is limited to 1.0% by weight or less.

R-Fe-C: Up to 0.5% by weight of Ti, Nb, and Zr are added to r-Al stainless steel in order to increase the toughness of the steel sheet and make it easier to manufacture, and to improve oxidation resistance. or 0.0% for the purpose of improving the peeling resistance of the oxide film.
Up to 3% by weight of rare earth elements such as Y, Ce, La, and Nd are added, but Fe-C with these elements added
r-Al stainless steel is also suitable for the present invention.

In this way, alumina whiskers are formed on the upper surface 2a of the base material 2 in FIG. 1 and on the inner peripheral surface of the through hole 3.

FIG. 3 is an enlarged sectional view of the vicinity of the surface 2a of the base material 2.

Alumina whiskers are indicated by reference numeral 4.

The length a of the alumina whisker 4 is 0°1 μm as described above.
By making the above selections, the radiation characteristics in the far infrared region can be dramatically improved, and the heating efficiency can be improved. Moreover, the alumina whiskers can dramatically increase the heat transfer area and improve heat conduction. Moreover, the film made of alumina whiskers improves corrosion resistance and can prevent oxidation, wet corrosion, and corrosion caused by high temperatures.

On the alumina whiskers 4 and the surface 2a of the base material 2, there is a catalyst 5, which is an active substance for flameless combustion of a gas with a high methane content, such as natural gas, at a low temperature of about 600°C or less.
be carried. The catalyst 5 is preferably a metal atom such as platinum or palladium, or an oxide of a metal such as nickel, cobalt or chromium. In particular, platinum and palladium are preferred because they have high activity against methane.

The catalyst body 1 thus obtained is fixed to the front part of the burner gage 7 of the catalytic combustion burner 6, as shown in FIG. A nozzle member 8 having a large number of nozzle holes is provided in the burner gas 7, and a fuel gas or a mixed gas of fuel gas and combustion air or oxygen is supplied to the nozzle member 8 through a pipe 9. It is pumped in the direction of arrow 43 in FIG. This allows efficient catalytic combustion. The fuel gas may be natural gas with a high methane content, or may be flammable gas such as propane gas, butane gas, or alcohol vapor.

FIG. 5 is a sectional view of a catalytic combustion burner 10 according to another embodiment of the present invention. In this embodiment, at least the front portion of the nozzle 11 is a catalyst body 12, and this catalyst body 12 has the same structure as the catalyst body 1 described above. Fuel gas or a mixed gas of fuel gas and combustion air or oxygen is fed under pressure from a pipe 14 to the chamber 13 of the burner gas 11. 5 FIG. 6 shows a cross section of a catalyst body 15 according to another embodiment of the present invention. FIG. 7 is a plan view of the catalyst body 15,
FIG. 8 is a side view of the catalyst body 15. The base material 16 of the catalyst body 15 has the shape of a right cylinder, and has through holes 1 perpendicular to its axis.
7 is formed. As described above, alumina whiskers are formed on the surface 16a of the base material 16 on the downstream side in the gas supply direction 18 and on the inner peripheral surface of the through hole 17, and the catalyst is supported on the alumina whiskers.

FIG. 9 shows a catalytic combustion burner 1 according to still another embodiment of the present invention.
FIG. 9 is a perspective view of FIG. 9, and FIG. 10 is a cross-sectional view thereof. The catalyst body 20 has a generally right cylindrical overall shape. In this catalyst body 20, alumina whiskers are formed on the inner circumferential surface of a base material 21 and on the inner circumferential surfaces of a large number of through holes 22, and the catalyst is supported on the alumina whiskers. The outer circumference of the catalyst body 20 is
Covered by a gate 23, this gate 23 and the catalyst body 2
Fuel gas is supplied from a pipe 25, or a mixed gas of fuel gas and combustion air or oxygen is supplied to the space 24 between the outer circumferential surface of the fuel gas and the outer circumferential surface of the fuel gas. In this way, the object to be heated is placed or moved on the inner peripheral surface of the catalyst body 20 and heated.

FIG. 11 is a perspective view of a catalytic combustion burner 26 according to still another embodiment of the present invention, and FIG.
6 is a sectional view of FIG. The catalyst body 27 has a right cylindrical shape closed by an end plate 28, and alumina whiskers are formed on the outer circumferential surface of the base material 28 and the inner circumferential surfaces of a large number of through holes 29.
A catalyst is supported on this alumina whisker. Catalyst body 27
A nozzle member 30 is disposed coaxially with the catalyst body 27 , and this nozzle member 30 extends along the axis of the catalyst body 27 and has a large number of nozzle holes. Gas is supplied, or a mixture of fuel gas and combustion air or oxygen is supplied. By arranging such a catalytic combustion burner 26 inside an object to be heated, which is formed into a cylindrical shape, for example, it is possible to heat the inner circumferential surface of the object to be heated.

FIG. 13 is a sectional view of a catalytic combustion burner 32 according to still another embodiment of the present invention. In this catalytic combustion burner 32,
The catalyst body 33 has a downwardly convex concave arc shape and is fixed to the burner case 34 . A nozzle member 35 is disposed inside the burner case 34, and the nozzle member 35 has a pipe line 3.
6 supplies fuel gas and the like as described above.

FIG. 14 is a sectional view of a catalytic combustion burner 37 according to still another embodiment of the present invention. A burner case 39 is provided on the catalyst body 38 which is curved convexly upward in FIG.
is placed. Fuel gas and the like are supplied to the nozzle member 40 from the conduit 41 in the same manner as described above.

In this way, the catalyst body of the present invention can be formed into a flat plate shape, a right cylindrical shape,
The catalytic combustion burner can be formed into a cylindrical shape, an arc shape, or any other desired shape, thereby making it possible to realize a catalytic combustion burner having a shape suitable for effectively heating the object to be heated.

In this way, the space occupied by the catalytic combustion burner can be reduced, contributing to downsizing of gas appliances. Furthermore, since there is a greater degree of freedom in the shape of the burner, the catalyst body can be made to match the shape of the object to be heated, and the object to be heated can be heated with a uniform temperature distribution.

The results of experiments conducted by the inventor of the present invention will be described.

As shown in Fig. 1, when Fe-Cr-A1 stainless steel containing Cr2O weight % and A 15 weight% is used as a test material and held at 925°C for 8 hours in an air atmosphere,
Alumina whiskers with a length of 2 μm or more were formed on the surface. This test piece was heated to 400°C, the infrared radiation intensity at a wavelength of 3 to 15 μm was measured, and the ratio (
That is, the emissivity) was found to be 0.8. As a comparison material, a commercially available 5US304 BA (bright annealing) finish was measured at the same temperature, and the emissivity was 0°2.

The experimental results of corrosion resistance will be described.

For the test piece (with alumina whiskers formed on the surface of Fe-Cr-AI stainless steel containing 20% by weight of Cr and 15% by weight of A) in the experimental results of the radiation characteristics described above, salt water according to Japanese Industrial Standards JIs Z2371 was used. When the spray test was conducted for 720 hours, no rust was observed in the sample material. On the other hand, comparative material (SUS304
) Rust was observed.

A PT catalyst of 1.0 wt % is supported on this whisker-bearing base material having a specific surface area of 2 m 2 /g using a conventional impregnation method. Hexachloroplatinic acid (H2Ptc16-6H,O)
The base material with whiskers is immersed in 200 ml of an aqueous solution in which 0.20 g of whisker is dissolved, and then washed and dried.

Similarly, 0.5 wt% of Pd metal is supported on the whiskered base material. 0.3 g of palladium chloride, 1 rnl of concentrated hydrochloric acid and 300 mj of ion-exchanged water! Soak, wash, and dry in a solution made using

Using the catalyst body 1 prepared in this way and using the burner assembled as shown in Fig. 4, a gas pressure of 30 m
When burned at mH2O, 350~6 depending on the amount of gas.
A surface temperature of 0.000C was obtained. The thickness of the burner at this time is 30 mm, which is about half of the conventional type. When we investigated the far-infrared radiation characteristics, we found that the far-infrared characteristics were superior to those of conventional catalytic combustion burners.

In addition, as shown in Figure 5, when assembled into an integrated burner and burned with propane gas without the dispersion nozzle,
It exhibited good far-infrared characteristics.

Effects of the Invention As described above, according to the present invention, catalytic combustion is effectively performed, and since the base material is made of Fe-Cr-AN steel, the strength is improved, and the action of alumina whiskers improves the strength. Corrosion resistance and durability are improved, the catalyst body can be formed into a desired shape, and effective heating becomes possible.

Furthermore, the amount of far-infrared radiation generated by both catalytic combustion and whiskers is greatly increased, and heating efficiency is improved. In this way, the catalytic combustion burner can be made smaller and thinner.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a catalyst 1 according to an embodiment of the present invention, FIG. 2 is a plan view of the catalyst body 1, FIG. 3 is an enlarged sectional view of the vicinity of the surface 2a of the base material 2, and FIG. 5 is a sectional view of a catalytic combustion burner 6 having a medium 1, FIG. 5 is a sectional view of a catalytic combustion burner 10 according to another embodiment of the invention, and FIG. 6 is a sectional view of a catalyst body 15 of another embodiment of the invention. , FIG. 7 is a plan view of the catalyst body 15, and FIG.
9 is a perspective view of a catalytic combustion burner 19 according to another embodiment of the present invention, FIG. 10 is a sectional view of the catalytic combustion burner 19 shown in FIG. 9, and FIG. 11 is a side view of the catalyst body 15. 12 is a sectional view of the catalytic combustion burner 26 shown in FIG. 11, and FIG. 13 is a perspective view of the catalytic combustion burner 26 according to another embodiment of the present invention. Burner 3
FIG. 14 is a cross-sectional view of a catalytic combustion burner 37 according to another embodiment of the present invention. 1, 12, 15, 2
1,27゜33.38... Catalyst body, 2,16... Base material, 3,22゜28... Hole, 4... Alumina whisker, 5... Catalyst, 6.10, 19, 26, 32.3
7...Catalytic combustion burner agent Patent attorney Number of strokes Keiichi Figure 1 Figure 3 Figure 4 Figure 5 Figure 2 Figure Figure 'VPA8 Figure 13 Figure 14

Claims (1)

[Claims] The surface of the base material made of Fe-Cr-Al stainless steel has alumina whiskers generated by oxidation treatment, and a catalyst is supported on the alumina whiskers to form a catalyst body. A catalytic combustion burner characterized by burning fuel gas.