JP6897289B2 - Bullion lance - Google Patents

Description

The present invention relates to a bullion cutting lance that melts the bullion adhering to the vicinity of the furnace mouth of a converter for refining pig iron by blowing oxygen gas.

During the operation of the converter, when oxygen gas is blown by the lance, if the molten steel scatters and adheres to the vicinity of the furnace opening, the molten steel tends to solidify and remain as bare metal. The bullion adhering to the vicinity of the furnace mouth grows due to repeated injection of oxygen gas by the lance, which hinders the supply of raw materials into the converter and the discharge of molten steel or slag from the converter. In addition, if the enlarged bullion peels off from the vicinity of the furnace mouth and falls, the temperature of the molten steel during operation drops sharply, disturbing the operating conditions and damaging the refractory provided inside the converter. There is a risk.

Therefore, it is necessary to remove the bullion before it grows significantly. To remove the bullion, the tip side of a bottomed cylindrical lance for removing the bullion (hereinafter referred to as "bullet cutting lance") is inserted into the furnace from the furnace opening and provided on the side wall near the tip of the lance. There is a method of blowing oxygen gas onto the bare metal from the discharge hole, and a specific example thereof is described in Patent Document 1.
Here, since the bullion adheres unevenly around the furnace ostium, if oxygen gas is evenly ejected from the bullion cutting lance toward the entire furnace ostium, it will be in the area where there is no bullion around the furnace ostium. There is a risk of damaging refractories. In this regard, the bullion cutting lance described in Patent Document 1 is provided with a plurality of oxygen discharge holes (oxygen discharge ports) for ejecting oxygen in a predetermined region in the circumferential direction of the bullion cutting lance, and oxygen is provided only in a specific direction. Since the gas is ejected, it is possible to prevent damage to the fireproof material.

Japanese Unexamined Patent Publication No. 2005-60747

By the way, by increasing the diameter of each oxygen discharge hole, the amount of oxygen gas sprayed increases, so that the efficiency of removing the bare metal can be expected to improve. Therefore, when an attempt was made to increase the diameter of each oxygen discharge hole based on the bullion cutting lance described in Patent Document 1, a pump that supplies oxygen gas to the bullion lance in order to obtain a predetermined spraying amount It turned out that the capacity needed to be increased more than expected. This is considered to be due to the large pressure loss that occurs with respect to the oxygen gas.
The present invention has been made in view of such circumstances, and an object of the present invention is to provide a bullion cutting lance capable of increasing the amount of oxygen gas sprayed while suppressing the pressure loss of oxygen gas.

The metal cutting lance according to the present invention according to the above object is formed in a bottomed cylindrical shape, and oxygen gas is blown into the converter from a plurality of openings provided on the side wall on the tip side to adhere to the periphery of the furnace opening. In a metal cutting lance for removing bare metal, an oxygen delivery path arranged along the axis inside the side wall and at a position having a distance from the side wall, and one side communicating with the oxygen delivery path and the oxygen. and one intermediate passage to send the oxygen gas from the delivery passage to the other side, one side each communicating with the other side of the intermediate flow passage, and a plurality of oxygen discharge holes other side communicates with each opening, wherein The cross-sectional area of the intermediate flow path that sends oxygen gas from the oxygen delivery path to the plurality of oxygen protrusions gradually decreases from one side to the other.
Further, in the bullion cutting lance according to the present invention, the plurality of oxygen discharge holes are arranged in the circumferential direction, and the intermediate flow path is the axial center of the bullion cutting lance in the cross section from one side to the other. The directional length may be reduced.

According to the bullion cutting lance according to the present invention, since the cross-sectional area of the intermediate flow path gradually decreases from one side to the other, the amount of oxygen gas blown is increased while suppressing the pressure loss of oxygen gas. It is possible to make it.

It is explanatory drawing of the bullion cutting lance which concerns on one Embodiment of this invention. It is a vertical cross-sectional view of the same bullion cutting lance. (A) and (B) are a cross-sectional view taken along the line AA and a cross-sectional view taken along the line BB of FIG. 2, respectively. (A) is a plan view of the intermediate flow path, and (B) and (C) are a cross-sectional view taken along the line LL and a cross-sectional view taken along the line MM of FIG. 4 (A), respectively. (A) is a vertical sectional view of a bullion cutting lance according to a comparative example of the present invention, and (B) is a QQ sectional view of FIG. 5 (A). (A) and (B) are schematic views of the oxygen gas flow path of the bullion cutting lance according to the embodiment and the comparative example of the present invention, respectively.

Subsequently, an embodiment embodying the present invention will be described with reference to the attached drawings, and the present invention will be understood.
As shown in FIGS. 1, 2, 3 (A) and 3 (B), the bullion cutting lance 10 according to the embodiment of the present invention is formed in a bottomed cylindrical shape and is formed on the side wall 11 on the tip side. Oxygen gas is blown into the converter 13 from the plurality of openings 12 provided to remove the bare metal P adhering to the periphery of the furnace opening 14. Hereinafter, a detailed description will be given.

As shown in FIGS. 1, 2, and 3 (A), the bullion cutting lance 10 is provided with an oxygen delivery path 16, a cooling water outward path 17, and a cooling water return path 18 inside the side wall 11. Inside the side wall 11, as shown in FIGS. 2 and 3 (A), a cylindrical partition member 15 long in the axial direction of the bullion cutting lance 10 and a partitioning material on the tip side of the bullion cutting lance 10 An insole 15a connected to 15 is provided, and an oxygen delivery path 16 is provided inside the partition member 15 and the insole 15a.

The oxygen delivery path 16 is located at the center of the cross section (that is, at a position having a distance from the side wall 11), is arranged along the axis of the bullion cutting lance 10, and is arranged from the base end side to the tip side of the bullion cutting lance 10. Send oxygen gas toward. The cross-sectional area of the oxygen delivery path 16 is constant along the flow of oxygen gas. Hereinafter, the axial center, the proximal end side, and the distal end side of the bullion cutting lance 10 are also simply referred to as "axial center", "base end side", and "tip end side", respectively. In the present embodiment, the cross-sectional area of the oxygen delivery path 16 is constant along the flow of oxygen gas, but it may be reduced or expanded to the extent that pressure loss does not occur.

Inside the side wall 11, a cylindrical partition member 15b is arranged so as to surround the partition member 15, a cooling water outflow path 17 is provided between the partition members 15 and 15b, and cooling is performed between the partition member 15b and the side wall 11. A water return route 18 is provided.
The cooling water outward path 17 has a cylindrical shape and is provided along the axis to send cooling water from the proximal end side to the distal end side.

The cooling water return path 18 is cylindrical and is formed so as to surround the cooling water outward path 17, and is provided along the axis. The tip side of the cooling water return path 17 and the tip side of the cooling water return path 18 are in communication with each other, and the cooling water that has passed through the cooling water return path 17 flows into the tip side of the cooling water return path 18 and is the base end of the cooling water return path 18. Sent to the side.
As shown in FIG. 2, a bottom plate 19 connected to the side wall 11 is provided at the tip of the bullion cutting lance 10, and a cooling water outward path 17 and a cooling water return path 18 are provided between the bottom plate 19 and the insole 15a. A bottom space portion 20 that communicates with each other is formed.

As shown in FIGS. 2 and 3B, one side of the metal cutting lance 10 is arranged in the cooling water outward path 17, and the other side is arranged in the bottom space 20. L-shaped pipes 21 are provided in parallel at intervals. A part of the cooling water flowing through the cooling water outward path 17 flows into one side of each pipe 21 and is sent into the bottom space 20 through each pipe 21 to cool the tip side of the metal cutting lance 10. , Flows into the cooling water return path 18.

Further, inside the side wall 11, one side is continuous (communication) with the tip end side of the oxygen delivery path 16, and one end (one side) is continuous with the other end (other side) of the intermediate flow path 22. A plurality of oxygen discharge holes 23 are provided. The intermediate flow path 22 is provided on the radial side of the metal cutting lance 10 with respect to the oxygen delivery path 16. Each oxygen discharge hole 23 has a circular cross section, its axis is arranged in the radial direction of the metal cutting lance 10, and the other side communicates with each opening 12 formed in the side wall 11. In the present embodiment, as shown in FIG. 3B, a plurality of openings 12 are arranged at intervals in a predetermined range in the circumferential direction of the bullion cutting lance 10, and the cross section of the other end of the intermediate flow path 22 is formed. And the cross section of one end of each oxygen discharge hole 23 have the same axial length of the bullion cutting lance 10.

As shown in FIG. 1, the bullion cutting lance 10 is used in a state where the tip side is inserted into the converter 13 from the furnace port 14 of the converter 13 and arranged vertically, and an oxygen delivery path is provided by a pump (not shown). Oxygen gas is supplied to the base end side of 16. The oxygen gas supplied to the base end side of the oxygen delivery path 16 passes through the oxygen delivery path 16 and the intermediate flow path 22 in order, flows into a plurality of oxygen discharge holes 23, and flows from each opening 12 around the furnace opening 14. It is sprayed on the inner wall of the converter 13. In FIG. 1, G indicates the blowing direction of oxygen gas.

Therefore, the intermediate flow path 22 sends the oxygen gas from the oxygen delivery path 16 from one side to the other side and directs the oxygen gas toward the oxygen discharge hole 23. Then, the bullion P adhering to the periphery of the furnace port 14 in the converter 13 is blown by oxygen gas blown from the plurality of openings 12 of the bullion cutting lance 10.
As shown in FIGS. 2 and 4 (A) to 4 (C), the cross-sectional area of the intermediate flow path 22 gradually decreases from one side (oxygen delivery path 16 side) to the other side (oxygen discharge hole 23 side). doing.

Here, as shown in FIGS. 4A to 4C, the cross-sectional area of the intermediate flow path 22 is a curved surface having the same distance from the axis of the metal cutting lance 10 (in the present embodiment, the metal). It is the area of the cut surface when the intermediate flow path 22 is cut by the arc) seen in the axial direction of the cutting lance 10. In the present embodiment, the cross section of the intermediate flow path 22 is the height of the cross section (the axial length of the bullion cutting lance 10) and the width of the cross section (the bullion cutting lance 10) from one side to the other. The length in the circumferential direction of) gradually decreases.
The reason why the cross section of the intermediate flow path 22 gradually decreases from one side to the other is to suppress the pressure loss generated in the oxygen gas. Hereinafter, the reason will be described in comparison with a comparative example.

The bullion cutting lance 30 according to a comparative example will be described with reference to FIGS. 5A and 5B.
As shown in FIGS. 5A and 5B, the bullion cutting lance 30 includes a cylindrical partition member 31a arranged inside the side wall 31, an insole 31b connected to the partition member 31a, and a partition. A cylindrical partition member 31c arranged so as to surround the member 31a is arranged.

An oxygen delivery path 32 is formed inside the partition member 31a and the insole 31b, a cooling water outward path 33 is formed between the partition member 31a and the partition member 31c, and a cooling water return path 34 is formed between the partition member 31c and the side wall 31. It is formed. Inside the side wall 31 , an intermediate flow path 35 communicating with the oxygen delivery path 32 and a plurality of oxygen discharge holes 36 having one side communicating with the intermediate flow path 35 are provided, and the side wall 31 has a plurality of each. A plurality of openings 37 are formed in which the other side of the oxygen discharge hole 36 communicates with the oxygen discharge hole 36.

The oxygen delivery path 32, the cooling water outward path 33, and the cooling water return path 34 are each long along the axis of the bullion cutting lance 30, and the cross-sectional area of the oxygen delivery path 32 is constant along the flow of oxygen gas.
One side of the intermediate flow path 35 is continuous with the tip end side of the oxygen delivery path 32, and the other side communicates with one side of each oxygen discharge hole 36, and the intermediate flow path 35 has a cross-sectional area along the flow of oxygen gas. Is expanding. The other side of each oxygen discharge hole 36 penetrates the side wall 31 to form an opening 37 in the side wall 31.
Oxygen gas is supplied to the base end side of the oxygen delivery path 32 in a state where the tip side of the bullion cutting lance 30 is inserted into the converter and arranged vertically. The oxygen gas passes through the oxygen delivery path 32, the intermediate flow path 35, and the plurality of oxygen discharge holes 36 in this order, and is blown into the converter from each opening 37.
A bottom space 39 is formed between the bottom plate 38 provided at the tip of the metal cutting lance 30 and the oxygen delivery path 32, and a part of the cooling water is provided inside the side wall 31 in the bottom space 39. A plurality of L-shaped tubes 40 to be sent inside are provided.

Next, the oxygen gas flow paths of the bullion cutting lances 10 and 30 will be examined.
The oxygen gas flow path of the bullion cutting lance 10 is composed of an oxygen delivery path 16, an intermediate flow path 22, and a plurality of oxygen discharge holes 23. , Schematically, can be shown as shown in FIG. 6 (A). As shown in FIG. 6A, the cross-sectional area of the flow path is constant in the oxygen delivery path 16 along the traveling direction of the oxygen gas, and is small at the point where the oxygen delivery path 16 is switched to the intermediate flow path 22. Therefore, it gradually shrinks in the intermediate flow path 22, shrinks at the point where the intermediate flow path 22 switches to the oxygen discharge hole 23, and is constant in the oxygen discharge hole 23. Since it is known that the pressure loss generated in the fluid can be ignored in the region where the cross-sectional area of the flow path gradually decreases, the metal cutting lance 10 substantially moves from the oxygen delivery path 16 to the intermediate flow path 22. A pressure loss occurs in the oxygen gas only at the portion where the intermediate flow path 22 switches to the oxygen discharge hole 23 and the portion where the oxygen gas blows out from the opening 12.

The oxygen gas flow path of the bullion cutting lance 30 is composed of an oxygen delivery path 32, an intermediate flow path 35, and a plurality of oxygen discharge holes 36. , Schematically, can be shown as shown in FIG. 6 (B). As shown in FIG. 6B, the cross-sectional area of the flow path is constant in the oxygen delivery path 32 along the traveling direction of the oxygen gas, and abruptly at the point where the oxygen delivery path 32 switches to the intermediate flow path 35. It becomes smaller, expands in the intermediate flow path 35 , shrinks at the point where the intermediate flow path 35 switches to the oxygen discharge hole 36, and is constant in the oxygen discharge hole 36.
That is, the cross-sectional area is temporarily reduced at the point where the oxygen delivery path 32 of the bullion cutting lance 30 is switched to the intermediate flow path 35, and then the cross-sectional area is rapidly expanded. As for the pressure loss that occurs, the bullion cutting lance 30 is larger than the bullion cutting lance 10.
As a result of calculating the loss coefficient with the bullion cutting lance 10 of the present invention shown in FIGS. 2 and 3 (A) and 3 (B) and the bullion cutting lance 30 shown in FIGS. 5 (A) and 5 (B), the bullion In the cutting lance 30, the loss coefficient ζ ₁ = 2.3 to 2.5, whereas in the bullion cutting lance 10, the loss coefficient ζ 2 = 0.04, and the pressure loss was reduced by about 1/60. ..

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and all changes in conditions that do not deviate from the gist are within the scope of the present invention.
For example, in the intermediate flow path, the cross-sectional area may gradually decrease from one side (upstream side) to the other side (downstream side), and the axis of the bullion cutting lance having a cross section from one side to the other side. The directional length (height) does not have to be reduced.
Further, the oxygen discharge holes do not have to be arranged in the circumferential direction at the same position in the axial direction of the bullion cutting lance, and may be arranged at different positions in the axial direction of the bullion cutting lance, for example. Further, the oxygen discharge hole does not have to have a circular cross section.

10: Metal cutting lance, 11: Side wall, 12: Opening, 13: Rotating furnace, 14: Furnace, 15: Partition material, 15a: Insole, 15b: Partition material, 16: Oxygen delivery path, 17: Cooling water Outward route, 18: Cooling water return route, 19: Bottom plate, 20: Bottom space, 21: Pipe, 22: Intermediate flow path, 23: Oxygen discharge hole, 30: Metal cutting lance, 31: Side wall, 31a: Partition material, 31b: Middle plate, 31c: Partition material, 32: Oxygen delivery path, 33: Cooling water outward path, 34: Cooling water return path, 35: Intermediate flow path, 36: Oxygen discharge hole, 37: Opening, 38: Bottom plate, 39: Bottom space, 40: pipe, G: oxygen gas spraying direction, P: bare metal

Claims (2)

In a bullion cutting lance, which is formed in a bottomed cylindrical shape and blows oxygen gas into the converter from a plurality of openings provided on the side wall on the tip side to remove the bullion adhering to the periphery of the furnace opening.
An oxygen delivery path located inside the side wall and at a position at a distance from the side wall along the axis, and one side communicates with the oxygen delivery path to send oxygen gas from the oxygen delivery path to the other side. A plurality of oxygen discharge holes having one intermediate flow path and one side communicating with the other side of the intermediate flow path and the other side communicating with each of the openings are provided, and oxygen gas from the oxygen delivery path is supplied to the plurality of oxygen gases. The intermediate flow path sent to the oxygen protrusion hole is a metal cutting lance characterized in that the cross-sectional area gradually decreases from one side to the other side. The plurality of oxygen discharge holes are arranged in the circumferential direction, and the intermediate flow path is characterized in that the axial length of the bullion cutting lance in the cross section decreases from one side to the other side. The bullion cutting lance according to claim 1.

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