JP2014185374A - Tuyere structure for melting furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To modify the opening space of the tip of the tuyere without affection of the droplet in the surface.SOLUTION: In a tuyere structure of a melting furnace 1, a plug-like member 20 not coming in contact with the inside surface 4a of a tuyere 4 is arranged inside the tip of the tuyere 4 facing the inside of the melting furnace 1 so that hot blast supplied into the melting furnace 1 passes through a clearance between the outer surface of the plug-like member 20 and the inside surface 4a of the tuyere 4. Since the opening space of the tip of the tuyere 4 is decreased by the cross sectional area of the plug-like member 20, the opening space is adjustable by setting an appropriate clearance according to the blast volume so that the flow rate of the hot blast does not vary. Since the plug-like member 20 is arranged with a clearance between the inside surface 4a of the tuyere 4 and it, there is no possibility of fastening between the inside surface 4a of the tuyere 4 and the outer surface of the plug-like member 20 owing to droplet.

Description

  The present invention relates to a tuyere structure of a melting furnace such as a cupola or a blast furnace.

  In order to melt iron sources such as iron scrap and pig iron, for example, a cupola (melting furnace) 1 as shown in FIG. 3 is used.

  In the cupola 1, the bed coke layer 10 is formed by filling the coke from the furnace bottom to a certain height. A plurality of tuyere 4 are provided along the circumferential direction at the lower part of the furnace wall facing the portion of the bed coke layer 10. Coke is burned by hot air blown from the tuyere 4 (including normal air and oxygen-enriched air, hereinafter collectively referred to as “hot air”). With this combustion heat, the iron source S such as iron scrap and pig iron charged in the upper part of the bed coke layer 10 is melted, and the molten iron (molten metal) is taken out from the hot water outlet 3 provided in the furnace bottom. In addition, the code | symbol 5 in a figure is a cooling device.

  The hot metal is supplied with carbon from the coke when the coke gap in the bed coke layer 10 is dropped. Further, since the bed coke layer 10 is gradually consumed due to combustion, for the purpose of compensating for this, the additional coke 11 and the new iron source S are alternately placed in the cupola 1 as shown in FIG. I am charging.

  By the way, the tuyere 4 conventionally used is a cylindrical member made of refractory or metal. The opening area of the tip of the tuyere 4 facing the furnace of the cupola 1 is always constant. For this reason, if the air flow rate is changed to adjust the amount of the cupola 1 discharged, the flow rate of the hot air blown from the tip of the tuyere 4 will also change.

  When the flow velocity changes, for example, as shown in FIGS. 4 (a) and 4 (b), the position where the hot air reaches in the furnace (the portion indicated by the dark color indicated by symbol A in the figure) changes, and the combustion in the furnace There is a problem that the state is not stable. FIG. 4A shows a state where hot air has not reached the core, and FIG. 4B shows a state where hot air has reached the core.

  For example, as shown in FIG. 5, a throttle sleeve 6 that contacts the inner surface 4 a of the tuyere 4 is provided as a technique for stabilizing the combustion state of the core even if the air flow rate changes. There is a technique for adjusting the inner diameter of the tip opening. Further, a technique for expanding and reducing the inner diameter of the tip opening portion of the tuyere 4 by inserting a throttling member made of a thin metal plate inside the sleeve 6 and operating the throttling member along the direction in which the tuyere 4 extends. (For example, refer to Patent Document 1).

JP-A-5-239520

  However, since the droplets scatter in the cupola, the droplets also adhere to the tuyere. For this reason, there is a possibility that the sleeve in the tuyere is fixed to the tuyere due to adhesion (noro) of the droplets and cannot be detached. Moreover, there is a possibility that the operation of the throttle body becomes impossible due to the fixing of the sleeve.

  Accordingly, an object of the present invention is to change the opening area of the tip of the tuyere without being affected by the droplets in the furnace.

  In order to solve the above problems, the present invention is arranged inside the tuyere tip facing the melting furnace, a plug-like member that does not contact the inner surface of the tuyere, and the hot air supplied into the melting furnace is A melting furnace tuyere structure passing through a gap between the outer surface of the plug-shaped member and the inner surface of the tuyere.

As a result, the opening area at the tip of the tuyere is reduced by the cross-sectional area of the plug-like member, so the opening area is adjusted by setting an appropriate gap according to the air flow rate so that the flow rate of hot air does not change Can be set.
Moreover, since the plug-shaped member is disposed with a gap between the inner surface of the tuyere, there is no fear that the inner surface of the tuyere and the outer surface of the plug-shaped member are fixed by the droplets.

In this configuration, the plug-like member can be held, for example, by a shaft member or the like disposed in the tuyere, but particularly when a fuel blowing pipe (lance pipe) is disposed in the tuyere, the fuel blowing is performed. It can be set as the structure which provided the plug-shaped member in the outer periphery of the pipe | tube.
Thereby, it is not necessary to provide a new member for supporting the plug-like member, and the structure inside the tuyere can be simplified.

  In each of these configurations, the plug-like member can be advanced and retracted in a direction connecting the front end side and the rear end side of the tuyere, and the opening area of the tuyere is variable by the advancement and retreat of the plug-like member. Can be adopted. Thereby, the opening area of a tuyere can be made variable only by moving a plug-shaped member, without replacing the plug-shaped member in a tuyere with a thing with a different magnitude | size or a shape. That is, the combustion state in the cupola can be easily adjusted during operation.

  According to the present invention, since the plug-like member that does not contact the inner surface of the tuyere is arranged inside the tip of the tuyere, an appropriate gap is set between the inner surface of the tuyere and the plug-like member in accordance with the air flow rate. Thus, the opening area can be adjusted so that the flow rate does not change. Moreover, since the plug-shaped member is disposed with a gap between the inner surface of the tuyere, it is possible to prevent the inner surface of the tuyere and the outer surface of the plug-shaped member from being fixed by a droplet.

1 shows an embodiment of the present invention, (a) is an enlarged longitudinal sectional view of a main part, (b) is a right side view of (a). Fig. 4 shows another embodiment of the present invention, in which (a) is an enlarged vertical sectional view of a main part in a state in which the plug-like member is retracted, (b) is a right side view of (a), and (c) is a plug-like member advanced The main part enlarged longitudinal cross-sectional view of the state which carried out, (d) is the right view of (c) Cross section of melting furnace (A) and (b) are cross-sectional views near the tuyere of the melting furnace Main section enlarged sectional view of the conventional example

  Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a melting furnace tuyere structure showing an embodiment of the present invention. In this embodiment, the melting furnace is a cupola, but it can also be used in a melting furnace other than the cupola, for example, a blast furnace. Hereinafter, the melting furnace will be described as a cupola 1. The entire structure of the cupola 1 can be the same as that of FIG. 3 used in the description of the conventional example, except for the tuyere 4.

  In the tuyere structure, as shown in FIG. 1, a plug-like member 20 that does not contact the inner surface 4 a of the tuyere 4 is arranged inside the tip of the tuyere 4 facing the cupola 1.

  The plug-like member 20 is attached to the outer periphery of the distal end portion 7 a of the fuel blowing pipe (lance pipe) 7 disposed in the tuyere 4. The plug-like member 20 and the fuel blowing pipe 7 are integrated, and the plug-like member 20 and the fuel blowing pipe 7 are detachable from the tuyere 4 from the rear end side of the tuyere 4. The plug-like member 20 is made of a heat-resistant material such as metal, like the fuel blowing pipe 7.

  The fuel blowing pipe 7 is arranged for blowing oxygen or coke breeze. The axial center of the fuel blowing pipe 7 is arranged so as to coincide with the axial center of the tuyere 4.

  The outer diameter of the plug-like member 20 is larger than the outer diameter of the general part of the fuel blowing pipe 7 (a place other than the part where the plug-like member 20 is provided). Further, the plug-like member 20 includes a cylindrical portion 20b having a constant outer diameter on the front end side, and a tapered portion 20a that decreases in diameter from the front end toward the rear end on the rear end side.

  A gap is set between the outer surface of the plug-like member 20 and the inner surface 4 a of the tuyere 4. In FIG. 1, a gap indicated by a symbol W <b> 1 is set over the entire circumference between the outer surface of the cylindrical portion 20 b and the inner surface 4 a of the tuyere 4. All the hot air supplied into the cupola 1 by the blowing means passes through this gap.

  By arranging the plug-like member 20, the opening area at the tip of the tuyere 4 is reduced by the cross-sectional area of the plug-like member 20. Therefore, the opening area can be adjusted by changing the plug-like member 20 to be arranged in accordance with the air flow rate and setting an appropriate gap. That is, it can be set so that the flow rate of the hot air does not change even if the air flow rate changes. At this time, if a plurality of plug members 20 having different shapes, sizes, and outer diameters are prepared in advance, the opening area can be appropriately changed by selectively using them.

  If the plug-like members 20 having different specifications are fixed to the fuel blowing pipe 7 respectively, the plug-like member 20 is attached to and detached from the fuel blowing pipe 7 each time the opening area is changed. There is no need to do it.

  Further, since the plug-like member 20 is disposed with a gap between the inner surface 4 a of the tuyere 4, the plug-like member 20 and the inner surface 4 a of the tuyere 4 are not in contact with each other. For this reason, there is no fear that the inner surface 4a of the tuyere 4 and the outer surfaces 20a, 20b of the plug-like member 20 are fixed by the droplets.

  FIG. 2 shows another embodiment. In this embodiment, the plug-like member 20 can be advanced and retracted along the axial direction of the tuyere 4 (the direction connecting the front end side and the rear end side of the tuyere 4). The plug-like member 20 moves forward and backward in the axial direction together with the fuel blowing pipe 7 by an operation from the rear end side of the tuyere 4 and can be fixed at an arbitrary position in the axial direction.

  The gap between the outer surface of the plug-shaped member 20 and the inner surface 4a of the tuyere 4 changes as the plug-shaped member 20 advances and retreats. In the retracted state shown in FIGS. 2A and 2B (the position where the tip of the fuel blowing pipe 7 is retracted by the distance L1 from the tip of the tuyere 4), the outer surface of the plug-like member 20 and the inner surface 4a of the tuyere 4 A gap indicated by a symbol W2 is set between the entire circumference. 2C and 2D, the outer surface of the plug-like member 20 and the wings are in the advanced state (the position where the tip of the fuel blowing pipe 7 is retracted from the tip of the tuyere 4 by a distance L2 (L1> L2)). Between the inner surface 4a of the mouth 4, a gap indicated by a symbol W3 is set over the entire circumference. That is, since the inner surface 4a of the tuyere 4 is a tapered surface that decreases in diameter toward the tip, the gap indicated by the symbol W3 is smaller than the gap indicated by the symbol W2 (W2> W3).

  By changing the gap, the opening area of the tuyere 4 can be adjusted. Adjustment is possible without steps. Thereby, the opening area of the tuyere 4 can be made variable only by moving the plug-like member 20 without replacing the plug-like member 20 in the tuyere 4 with ones having different sizes, shapes, and outer diameters. That is, the combustion state in the cupola 1 can be easily adjusted during operation. For example, when the blast volume changes during operation, the flow rate of hot air can be easily adjusted.

  In this embodiment, the plug-like member 20 is provided with a tapered portion 20a having a reduced diameter as it goes from the front end to the rear end. Alternatively, as in the above-described embodiment, a cylindrical portion 20b having a constant outer diameter on the front end side and a taper portion 20a that decreases in diameter from the front end toward the rear end on the rear end side may be adopted. Good.

  In this embodiment, as the plug-like member 20, a pipe body constituting the fuel blowing pipe 7 is expanded in a trumpet shape at the tip end portion 7a. Instead of this, the plug-like member 20 made of another member may be fixed to the outer periphery of the distal end portion 7a of the fuel blowing pipe 7 made of a constant pipe diameter, as in the above-described embodiment. In any embodiment, the plug-like member 20 only needs to block a part of the opening of the tuyere 4, and the member may be solid or hollow.

  Further, in these embodiments, the plug-like member 20 is provided in the fuel blowing pipe 7, but the plug-like member 20 may be held by a shaft member disposed in the tuyere 4, for example. The shaft member can be disposed, for example, along the axis of the tuyere 4 or concentrically.

  At this time, by making the shaft member advanceable and retreatable in the axial direction of the tuyere 4 and making the axial position of the plug-shaped member 20 relative to the tuyere 4 variable, the opening area of the tuyere 4 can be easily made as described above. It can be configured to be adjustable.

1 Melting furnace (cupola)
2 Inlet 3 Outlet 4 Tuyere 4a Inner surface 5 Cooling device 6 Sleeve 7 Fuel injection pipe (lance pipe)
7a Tip part 20 Plug-like member 20a Taper part 20b Cylindrical part 10 Bed coke layer 11 Additional coke S Iron source

Claims (3)

  A plug-like member that does not contact the inner surface of the tuyere is arranged inside the tuyere tip facing the melting furnace, and the hot air supplied into the melting furnace has an outer surface of the plug-like member and an inner surface of the tuyere The tuyere structure of the melting furnace that passes through the gap between.   2. The tuyere structure of a melting furnace according to claim 1, wherein the plug-like member is provided on an outer periphery of a fuel blowing pipe disposed in the tuyere.   The plug-shaped member can be advanced and retracted in a direction connecting the tip end side and the rear end side of the tuyere, and the opening area of the tuyere tip is variable by the advancement and retreat of the plug-shaped member. Item 3. The tuyere structure of the melting furnace according to item 1 or 2.

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