JP2001272182A - Dust collecting hood for molten metal smelting facility - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dust collecting hood for a molten metal smelting facilities which is capable of eliminating the damage of a tube matrix or a spray deposit due to an impact load upon removing ground metal and contriving the elongation of the life of a membrane panel. SOLUTION: The dust collecting hood for molten metal smelting facilities having a water-cooled membrane panel 20 consisting of tubes 18 and fins 16 characteristically has protective plates 26 attached to the surface of the fins 16 inside of a furnace and projected so as to exceed the height of the tubes 18.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dust collecting 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 collecting hood.

[0002]

2. Description of the Related Art In a facility exposed to a high-temperature gas atmosphere such as a steelmaking converter and a pretreatment facility, a membrane-type cooling system in which a number of cooling water tubes are welded in a substantially parallel state via fins. Structure (hereinafter “membrane panel”)
Has been adopted.

[0003]

In such a water-cooled membrane panel, there is a problem that the tube is reduced in thickness due to abrasion due to dust contained in exhaust gas and oxidative corrosion due to high-temperature gas and ingot adhesion. . Therefore, in order to suppress the thinning of the tube of the water-cooled membrane panel and prevent the life from being shortened, the inner surface exposed to high-temperature exhaust gas is sprayed with ceramic spray with excellent wear resistance and corrosion resistance. 2. Description of the Related Art There is known a technique for spraying an excellent stainless steel spray and a self-fluxing alloy excellent in abrasion resistance and corrosion resistance.

[0004] However, in the refining of molten metal, splash of molten metal is generated, so that the metal is strongly attached to the surface of the membrane panel, and the metal is frequently removed between 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 thermal spray coating formed by the normal thermal spraying peels off, and the wear of the water-cooled tube main body also remarkably progresses. Therefore, the present invention
It is an object of the present invention to provide a membrane panel surface protection technology that solves the above-mentioned problems of the conventional technology.

[0005]

Means for Solving the Problems The inventors of the present invention have made intensive studies to achieve the above object, and as a result, have conceived an invention having the following features as the main components. That is, the dust collecting hood for a molten metal refining facility of the present invention is a dust collecting hood for a molten metal refining facility having a water-cooled membrane panel composed of a tube and a fin. And a protection plate protruding beyond the mounting position.

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 reduced by the conventional method. In this way, the protective plate does not act directly on the membrane panel, so that the thermal spray coating that may be formed on the surface of the membrane panel including the tube peels off, or the thermal spray coating The life of the membrane panel can be prolonged without abrasion of the tube base material having no gap. The protection plate is
By simplifying the shape, even if the protective plate is deformed or worn due to an impact load at the time of removing the metal, the repair becomes easy. Therefore, unlike the related 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 significantly reduced.

[0007]

FIG. 1 schematically shows an embodiment of an exhaust gas 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 a hot metal transport container 11 (hereinafter, referred to as “topy car”). A lower hood 12 for effectively collecting exhaust gas generated by the hot metal pretreatment is provided at a lower portion of the lower hood 12, which is opened at a position away from the hot metal, and is formed at an upper hood 13 at a central portion thereof. It is connected to a dust collection duct 14 guided to an exhaust gas treatment facility (not shown).

Since the exhaust gas during processing has a high temperature atmosphere of about 1500 ° C. above the opening of the torpedo car 11, the lower hood 12 and a part of the dust collecting panel 10 above the upper hood 12, ie, the upper part, As shown in FIGS. 2 and 3, a membrane panel 20 including a number of cooling tubes 16 and fins 18 is provided on the inner surface of the hood 13. Such a membrane panel 20 has a tube-fin welding structure in which a number of cooling tubes 16 are arranged adjacent to each other and fins 18 are welded between the tubes 16.
The cooling water is supplied from the drain header 23 and recirculated from the drain header 23 through a circulation pump (not shown), and is used for efficiently cooling a large area inside the lower hood 12 and the upper hood 13.

In the exhaust gas collecting hood 10 for hot metal pretreatment according to the present invention, as shown in FIG. 3, the side of the membrane panel 20 which comes into contact with the exhaust gas (hereinafter referred to as "furnace inside").
On the surface of the fin 18, a thermal spray coating covering the surface of the tube 16 and a protection plate 26 for protecting the tube 16 itself are welded and fixed.

The protective plate 26 is made of, for example, low-carbon steel which is inexpensive and easily available, and is provided with fins 18.
A height H projecting substantially vertically into the furnace beyond the height h of the tube 16 projecting from the surface;
It is formed in a rectangular plate shape having a width W slightly smaller than the distance therebetween and a length L along the longitudinal direction of the tube 16.

The tube 16 of the protection plate 26 is used.
The protruding amount (Hh) exceeding the height h is 10 to 20 mm
It is desirable to be within the range. The reason is that if it exceeds 20 mm, the cooling effect at the tip of the protection plate is reduced, so that a difference in thermal expansion between the fins 18 and the protection plate 26 occurs, and the protection plate 26 is thermally deformed. This is because the life before the height of the tube becomes shorter due to wear of the tip of the protection plate. Further, the protruding height H of the fins 18 does not have to be the same for all the fins 18, and may be formed higher, for example, for fins closer to the hood lower opening. it can.

It is preferable that the shape of the protection plate 26 be as simple as possible. For example, the protection plate 26 may have a triangular prism shape in addition to a rectangular plate shape, but is limited to these shapes. Not something. Thus, the protection plate 2
By simplifying the shape of No. 6, when the protective plate is deformed or worn due to an impact load at the time of removing the metal, repair is easy and the maintenance cost of the hood can be greatly reduced.

Further, the inner surface of the membrane panel 20 located between the adjacent protective plates 26, that is, the outer surface of each tube 16 and the surface of the fin 18 other than the portion where the protective plate 26 is attached, Thermal spray coating of self-fluxing alloy 2
4 are formed. This self-fluxing alloy is JIS H
8303, nickel-based alloys, cobalt-based alloys, or other copper-based alloys with B or Si
Such a self-fluxing alloy is sprayed on the outer surface of the tube 16 inside the furnace of the membrane panel 20 under a certain condition capable of forming a semi-molten coating film. After forming the coating, a fusing treatment is performed under a temperature condition of 1000 to 1100 ° C. to form a thermal spray coating 24 having high adhesion to the membrane panel 20.

FIG. 4 shows the distribution state of the ingots 28 attached to the surface of the membrane panel in the exhaust gas collecting hood in which the protective plate 26 configured as described above is provided on the surface of the fin 18.
FIG. 5 also shows the distribution state of the ingots 28 according to the prior art without the protection plate 26.

As can be understood from these figures, in the conventional membrane panel without the protective plate 26, the metal spouted from the inside of the molten metal container is formed by the sprayed coating 24 formed on the outer surface of the tube 16 and the fins. 16 directly collides with the surface, and adheres and accumulates there. In the membrane panel provided with the protection plate according to the present invention, FIG.
As compared with the conventional membrane panel shown in FIG. 1, the unevenness of the inner surface of the furnace is large, so that the amount of slab is increased, but the protection plate 26 is configured to receive the impact of the jig 30 when the slab is removed. Therefore, the tube 18 and the thermal spray coating 24 are not damaged.

That is, at the time of peeling / removing the adhered metal 28, the vibration or impact load applied to the adhered metal 28 is:
In the case of the prior art as shown in FIG. 5, since it is transmitted directly to the membrane panel, the tube 18 and the thermal spray coating 24
However, in the embodiment according to the present invention as shown in FIG. 4, since the power is transmitted to the protection plate 26, the tube 18 and the thermal spray coating 24 are not damaged.

[0017]

As described above, according to the present invention, although the amount of metal directly adhering to the surface of the membrane panel increases, the impact load at the time of peeling and removing these adhered metal is as follows. Since the protection plate is received without directly acting on the membrane panel as in the related art, the tube and the thermal spray 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 collection hood for a molten metal refining facility of the present invention.

FIG. 2 is a schematic plan view and a 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 according to an embodiment of the present invention.

FIG. 4 is a cross-sectional view showing a distribution of a metal layer attached to a membrane panel in one embodiment of the present invention.

FIG. 5 is a cross-sectional view showing distribution of a metal layer deposited on a membrane panel according to a conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Dust collection hood 11 Topy car 12 Lower hood 13 Upper hood 14 Dust collection duct 16 Fin 18 Tube 20 Membrane panel 24 Self-fluxing alloy spray coating 26 Protective plate 28 Ingot 30 Jig for removing ingot

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tomonori Kamiyama 1 Kawasaki-cho, Chuo-ku, Chiba-city, Chiba Prefecture Inside the Technical Research Institute of Kawasaki Steel Co., Ltd. (72) Kuniyoshi Oyama 1 Kawasaki-cho, Chuo-ku, Chiba-shi, Chiba Kawasaki (72) Inventor Tomoyuki Kishinami 1 Kawasaki-cho, Chuo-ku, Chiba-shi, Chiba Prefecture F-term (reference) 4K002 BA09 4K014 AD13 4K056 DC03

Claims (1)

[Claims] 1. A dust collecting hood for a molten metal refining facility having a water-cooled membrane panel comprising a tube and a fin, wherein a protective plate protruding beyond the tube height is attached to a furnace inner surface of the fin. A dust collecting hood for a molten metal refining facility.