JP4795506B2 - Dust collection hood for molten metal refining equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a dust collection hood for a molten metal refining facility, and more particularly, to a technique for extending the life of a water-cooled membrane panel constituting the dust collection hood.
[0002]
[Prior art]
In equipment exposed to high-temperature gas atmospheres such as steelmaking converters and pretreatment equipment, a membrane type cooling structure (hereinafter referred to as “ Membrane panel ”) is used.
[0003]
[Problems to be solved by the invention]
In such a water-cooled membrane panel, there is a problem that the tube is thinned due to wear due to dust contained in the exhaust gas or oxidative corrosion due to high-temperature gas and metal adhesion.
Therefore, in order to suppress the thinning of the tube of the water-cooled membrane panel and prevent a decrease in the service life, the inner surface exposed to the high temperature exhaust gas has a ceramic spray with excellent wear resistance and corrosion resistance. Techniques for spraying excellent stainless steel sprays, as well as self-fluxing alloys excellent in wear resistance and corrosion resistance are known.
[0004]
However, in the refining of the molten metal, a splash of the molten metal is generated, and therefore, the adhesion of the metal to the surface of the membrane panel is intense, and the metal is often removed between the operations. In such a case, there is a problem that the impact load on the membrane panel due to the removal of the metal is large, the sprayed coating formed by normal spraying is peeled off, and further, the wear of the water-cooled tube body is significantly advanced.
Accordingly, an object of the present invention is to provide a membrane panel surface protection technique that solves the above-described problems of the prior art.
[0005]
[Means for Solving the Problems]
As a result of intensive studies to achieve the above object, the inventors have come up with an invention having the following contents. That is, the dust collection hood for a molten metal refining facility according to the present invention is the dust collection hood for a molten metal refining facility having a water-cooled membrane panel composed of a tube and a fin having a sprayed coating formed on the inner surface of the furnace. A protective plate protruding beyond the height of the tube is attached to the inner surface of the furnace.
[0006]
According to such a configuration, although the amount of metal that adheres and accumulates on the surface of the membrane panel including the outer surfaces of the tubes and fins increases, the impact load when removing the adhered metal is the same as in the past. Since the protective plate does not act directly on the panel, the sprayed coating that may be formed on the surface of the membrane panel including the tube peels off, or the tube has no sprayed coating. The lifetime of the membrane panel can be extended without the base material being worn.
By making the shape of the protection plate simple, even when the protection plate is deformed or worn out due to an impact load at the time of metal removal, the protection plate can be easily repaired. Therefore, unlike the prior art, it is not necessary to newly manufacture or renew the panel due to the life of the membrane panel, so that the maintenance cost can be greatly reduced.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 schematically shows an embodiment of an exhaust gas dust collecting hood for a molten metal refining facility according to the present invention. The dust collecting hood 10 constitutes a dust collecting device for collecting exhaust gas generated by hot metal pretreatment in the hot metal transport container 11 (hereinafter referred to as “topy car”). The lower hood 12 is opened at a position away from the lower hood 12 for effectively collecting the exhaust gas generated by the hot metal pretreatment, and the upper hood 13 is formed at the center thereof. It continues to the dust collection duct 14 guided to the exhaust gas treatment facility (not shown).
[0008]
At the upper part of the opening of the topped car 11, the exhaust gas temperature during processing is a high temperature atmosphere of about 1500 ° C., so that the lower hood 12 and a part of the dust collection panel 10 above it, that is, the upper hood 13 As shown in FIGS. 2 and 3, the inner surface is provided with a membrane panel 20 composed of a large number of cooling tubes 18 and fins 16 . Such membrane panel 20, a plurality of cooling tubes 18 placed adjacent, without a tube fins welded structure fin 16 is welded between the tubes 18 from the water supply header 22 and each tube 18 Cooling water is supplied and recirculated from the drainage header 23 via a circulation pump (not shown), and is used for the purpose of efficiently cooling a large area inside the lower hood 12 and the upper hood 13.
[0009]
In the hot metal pretreatment exhaust gas dust collecting hood 10 according to the present invention, as shown in FIG. 3, on the surface of the fin 16 on the side in contact with the exhaust gas of the membrane panel 20 (hereinafter referred to as “furnace inside”) A thermal spray coating covering the surface of the tube 18 and a protective plate 26 for protecting the tube 18 itself are welded and fixed.
[0010]
The protection plate 26 is made of, for example, low-cost and readily available low carbon steel, and has a height H that protrudes substantially vertically to the furnace interior beyond the height h of the tube 18 protruding from the surface of the fin 16. In addition, it is formed in a rectangular plate shape having a width W slightly smaller than the distance between adjacent tubes 18 and a length L along the longitudinal direction of the tubes 18 .
[0011]
The protruding amount (Hh) of the protective plate 26 that exceeds the height h of the tube 18 is preferably in the range of 10 to 20 mm. The reason is that if the thickness exceeds 20 mm, the cooling effect at the tip of the protective plate is reduced, so that a difference in thermal expansion between the fins 16 and the protective plate 26 occurs, and the protective plate 26 is thermally deformed. This is because the life until the tube height is shortened due to wear of the protective plate tip. Further, the protruding height H of the fin 16, to be the same height with respect to all the fins 16 may, for example, with respect to the fins from the hood bottom opening in closer portion, also be higher form it can.
[0012]
Moreover, it is preferable that the shape of the protective plate 26 is as simple as possible. For example, in addition to the rectangular plate shape, the shape can be a triangular prism shape, but the shape is not limited to these shapes. .
By simplifying the shape of the protective plate 26 in this way, when the protective plate is deformed or worn out due to an impact load at the time of metal removal, it can be easily repaired and the maintenance cost of the hood can be greatly reduced. effective.
[0013]
Further, the inner surface of the membrane panel 20 positioned between the adjacent protective plates 26, that is, the outer surface of each tube 18 and the surface of the fin 16 other than the mounting portion of the protective plate 26 are self-fluxing alloys. The thermal spray coating 24 is formed. This self-fluxing alloy is a nickel-base alloy or cobalt-base alloy as defined in JIS H 8303, or other copper-base alloy containing a flux component such as B or Si. After forming an alloy film by spraying a self-fluxing alloy on the outer surface of the tube 18 inside the furnace of the membrane panel 20 under a certain condition capable of forming a semi-molten film, the temperature is 1000 to 1100 ° C. A fusing process is performed to form a thermal spray coating 24 with high adhesion to the membrane panel 20.
[0014]
In the exhaust gas dust collecting hood provided with the protective plate 26 configured as described above on the surface of the fin 16 , the distribution state of the adhesion metal 28 on the membrane panel surface is schematically shown in FIG. The distribution state of the adhesion metal 28 according to the prior art without the plate 26 is also shown in FIG.
[0015]
As can be understood from these drawings, in the conventional membrane panel not provided with the protective plate 26, the bare metal ejected from the molten metal container is applied to the surface of the spray coating 24 and the fin 16 formed on the outer surface of the tube 18. It collides directly and adheres and accumulates there. In the membrane panel provided with the protective plate according to the present invention, since the unevenness of the inner surface of the furnace is larger than that of the conventional membrane panel shown in FIG. Since the protection plate 26 is configured to receive the impact caused by the above, the tube 18 and the thermal spray coating 24 are not damaged.
[0016]
That is, at the time of peeling / removing the adhered metal 28, the vibration and impact load applied to the adhered metal 28 are directly transmitted to the membrane panel in the case of the prior art as shown in FIG. 18 and the sprayed coating 24 are damaged, but in the embodiment according to the present invention as shown in FIG. 4, since it is transmitted to the protective plate 26, the tube 18 and the sprayed coating 24 are not damaged.
[0017]
【The invention's effect】
As described above, according to the present invention, although the amount of metal directly attached to the surface of the membrane panel increases, the impact load at the time of peeling and removing these adhered metal is the same as the conventional membrane. Since the protective plate is received without acting directly on the panel, the tube and the sprayed coating are not damaged, and the life of the membrane panel can be extended.
[Brief description of the drawings]
FIG. 1 is a schematic view showing an embodiment of an exhaust gas dust collecting hood for a molten metal refining facility according to the present invention.
FIG. 2 is a schematic plan view and side view of a membrane panel according to an embodiment of the present invention.
FIG. 3 is a cross-sectional view showing a membrane panel and a protective plate formed thereon in one embodiment of the present invention.
FIG. 4 is a cross-sectional view showing a distribution of a metal layer attached on a membrane panel according to an embodiment of the present invention.
FIG. 5 is a cross-sectional view showing the distribution of a metal layer attached on a membrane panel according to the prior art.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Dust collection hood 11 Topped car 12 Lower hood 13 Upper hood 14 Dust collection duct 16 Fin 18 Tube 20 Membrane panel 24 Self-fluxing alloy sprayed coating 26 Protective plate 28 Ingot 30 Ingot removal jig

Claims (1)

In a dust collection hood for a molten metal refining facility having a water-cooled membrane panel composed of a tube and fins having a thermal spray coating formed on the inner surface of the furnace, the fin inner surface protrudes beyond the tube height. A dust collecting hood for a molten metal refining facility, wherein a protective plate is attached.

Images