JP2018188698A - Lance for cutting deposited metal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lance for cutting deposited metal to increase the spraying amount of oxygen gas while suppressing the pressure loss of oxygen gas.SOLUTION: The lance 10 is formed in a bottomed cylindrical shape and blows oxygen gas into a converter 13 through a plurality of openings 12 provided in a side wall 11 on the front end side to remove the metal deposited on the periphery of a furnace port 14. The lance has: an oxygen delivery passage 16 arranged along the axis at a position inside the side wall 11 and at a distance from the side wall 11; an intermediate flow path 22 with a side communicating with the oxygen delivery passage 16 for feeding oxygen gas from the oxygen delivery passage 16 to the other side; and a plurality of oxygen discharge holes 23, one side of which communicates with the other side of the intermediate flow path 22 and the other side communicates with each opening 12. In the intermediate flow path 22, the sectional area gradually decreases from one side to the other side.SELECTED DRAWING: Figure 2

Description

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

During 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 port, the molten steel tends to remain as a solid metal. The bare metal attached to the periphery of the furnace port grows by repeated blowing of oxygen gas by the lance, thereby hindering supply of raw materials into the converter and 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 rapidly, and the operation conditions are disturbed, or the refractory provided inside the converter is damaged. There is a fear.

Therefore, it is necessary to remove the bullion before the bullion grows greatly. To remove the bullion, insert the tip of the bottomed cylindrical lance for removing the bullion (hereinafter referred to as the “bulb cutting lance”) into the furnace through the furnace port and place it on the side wall near the lance tip. There is a method in which oxygen gas is sprayed onto the metal from the discharge hole, and a specific example is described in Patent Document 1.
Here, since the bullion is unevenly attached around the furnace mouth, if oxygen gas is uniformly ejected from the bullion cutting lance to the whole furnace mouth, it is in the area without bullion around the furnace mouth. There is a risk of refractory damage. 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, so Since gas is blown out, damage to the refractory can be prevented.

JP 2005-60747 A

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

The metal cutting lance according to the present invention that meets the above-mentioned purpose is formed in a bottomed cylindrical shape, and oxygen gas is blown into the converter from a plurality of openings provided in the side wall on the front end side, and adhered to the periphery of the furnace mouth. In the bullion cutting lance for removing the bullion, an oxygen delivery path disposed along the axial center at a position inside the side wall and at a distance from the side wall, and one side communicating with the oxygen delivery path An intermediate flow path for sending oxygen gas from the delivery path to the other side; a plurality of oxygen discharge holes each having one side communicating with the other side of the intermediate flow path and the other side communicating with the openings; The cross-sectional area of the road gradually decreases from one side to the other side.
Further, in the metal cutting lance according to the present invention, the plurality of oxygen discharge holes are arranged in the circumferential direction, and the intermediate flow path has an axial center of the metal cutting lance in a cross section from one side to the other side. The direction length may be reduced.

According to the metal 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 side, the amount of oxygen gas sprayed 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 longitudinal cross-sectional view of the same metal cutting lance. (A), (B) is AA sectional drawing and BB sectional drawing of FIG. 2, respectively. (A) is a plan view of the intermediate flow path, and (B) and (C) are an LL sectional view and an MM sectional view of FIG. 4 (A), respectively. (A) is a longitudinal cross-sectional view of the bullion cutting lance which concerns on the comparative example of this invention, (B) is QQ sectional drawing of FIG. 5 (A). (A), (B) is a schematic diagram of the flow path of oxygen gas of the bullion cutting lance according to one embodiment and a comparative example of the present invention, respectively.

Next, embodiments of the present invention will be described with reference to the accompanying drawings for understanding of the present invention.
As shown in FIGS. 1, 2, 3 (A) and 3 (B), a bare metal cutting lance 10 according to an embodiment of the present invention is formed in a bottomed cylindrical shape, and is formed on a side wall 11 on the distal end side. Oxygen gas is blown into the converter 13 from the plurality of openings 12 provided, and the metal P adhering to the periphery of the furnace port 14 is removed. Details will be described below.

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 forward path 17, and a cooling water return path 18 inside the side wall 11. As shown in FIG. 2 and FIG. 3A, on the inner side of the side wall 11, a cylindrical partition member 15 that is long in the axial direction of the metal cutting lance 10, and a partition material on the tip side of the metal cutting lance 10. 15 is provided, and an oxygen delivery path 16 is provided inside the partition member 15 and the intermediate bottom 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 disposed along the axis of the bare metal cutting lance 10, and extends from the proximal end side to the distal end side of the bare metal 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 metal cutting lance 10 are also simply referred to as “axial center”, “proximal end side”, and “distal 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 no pressure loss occurs.

Inside the side wall 11, a cylindrical partition member 15 b is disposed so as to surround the partition member 15, and a cooling water forward path 17 is provided between the partition members 15 and 15 b, and cooling is performed between the partition plate 15 b and the side wall 11. A water return path 18 is provided.
The cooling water outgoing path 17 is cylindrical and is provided along the axis, and sends the cooling water from the proximal end side toward the distal end side.

The cooling water return path 18 is formed in a cylindrical shape so as to surround the cooling water outbound path 17 and is provided along the axis. The leading end side of the cooling water forward path 17 and the leading end side of the cooling water return path 18 are in communication, and the cooling water that has passed through the cooling water forward path 17 flows into the leading end 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. Between the bottom plate 19 and the middle bottom 15 a, a cooling water forward path 17 and a cooling water return path 18 are provided. A communicating bottom space 20 is formed.

As shown in FIG. 2 and FIG. 3 (B), a plurality of pieces of which one side is arranged in the cooling water forward passage 17 and the other side is arranged in the bottom space portion 20 are respectively provided on the inner end side of the metal cutting lance 10. The L-shaped pipes 21 are provided in parallel at intervals. A part of the cooling water flowing through the cooling water going path 17 flows into one side of each pipe 21 and is sent into the bottom space portion 20 through each pipe 21 to cool the tip side of the metal cutting lance 10. Then, it flows into the cooling water return path 18.

Further, on the inner side of the side wall 11, one side (one side) continues to the other end (the other side) of the intermediate channel 22 and one end (one side) continues to the leading end side of the oxygen delivery path 16 (one side). A plurality of oxygen discharge holes 23 are provided. The intermediate flow path 22 is provided on the radially outer side of the metal cutting lance 10 with respect to the oxygen delivery path 16. Each oxygen discharge hole 23 is circular in cross section, and its axis is disposed in the radial direction of the bare metal 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. 3 (B), the plurality of openings 12 are arranged at predetermined intervals in the circumferential direction of the bare metal cutting lance 10, and a cross section at the other end of the intermediate flow path 22. And the cross-section of one end of each oxygen discharge hole 23 have the same length in the axial direction of the bare metal cutting lance 10.

As shown in FIG. 1, the metal 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 is arranged vertically. The oxygen gas is supplied to the base end side of 16. The oxygen gas supplied to the proximal end side of the oxygen delivery path 16 sequentially passes through the oxygen delivery path 16 and the intermediate flow path 22 and flows into the plurality of oxygen discharge holes 23, and from each opening 12 around the furnace port 14. It is sprayed on the inner wall of the converter 13. In FIG. 1, G indicates the direction of blowing 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 it toward the oxygen discharge hole 23. Then, the metal P attached to the periphery of the furnace port 14 in the converter 13 is melted by oxygen gas sprayed from the plurality of openings 12 of the metal cutting lance 10.
As shown in FIGS. 2 and 4A to 4C, the intermediate flow path 22 gradually decreases in cross-sectional area 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 bullion cutting lance 10 (in this embodiment, the bullion This is the area of the cut surface when the intermediate flow path 22 is cut by a circular arc when viewed in the axial direction of the cutting lance 10. In the present embodiment, the cross section of the intermediate flow path 22 has a cross section height (length in the axial direction of the metal cutting lance 10) and a cross section width (the metal cutting lance 10) from one side to the other side. In the circumferential direction) gradually decreases.
The reason why the cross section of the intermediate flow path 22 gradually decreases from one side to the other side is to suppress pressure loss that occurs in oxygen gas. Hereinafter, the reason will be described in comparison with a comparative example.

With reference to FIG. 5 (A) and (B), the metal cutting lance 30 which concerns on a comparative example is demonstrated.
As shown in FIGS. 5A and 5B, the bullion cutting lance 30 includes a cylindrical partition member 31a disposed inside the side wall 31, a midsole 31b connected to the partition member 31a, and a partition. A cylindrical partition plate 31c is disposed so as to surround the material 31a.

An oxygen delivery path 32 is formed inside the partition member 31a and the inner bottom 31b, a cooling water forward 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 plate 31c and the side wall 31. Is formed. Inside the side wall 11, an intermediate flow path 35 communicating with the oxygen delivery path 32 and a plurality of oxygen discharge holes 36 each having one side communicating with the intermediate flow path 35 are provided. A plurality of openings 37 communicating with the other side of the oxygen discharge hole 36 are formed.

The oxygen delivery path 32, the cooling water forward path 33, and the cooling water return path 34 are each long along the axis of the metal cutting lance 30, and the cross-sectional area of the oxygen delivery path 32 is constant along the flow of oxygen gas.
The intermediate flow path 35 has one side continuous to the distal end side of the oxygen delivery path 32 and the other side communicating with one side of each oxygen discharge hole 36. 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, and an opening 37 is formed in the side wall 31.
The metal cutting lance 30 is supplied with oxygen gas to the proximal end side of the oxygen delivery path 32 in a state where the distal end side is inserted into the converter and arranged vertically. The oxygen gas sequentially passes through the oxygen delivery path 32, the intermediate flow path 35, and the plurality of oxygen discharge holes 36, 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 placed inside the side wall 31 at the bottom space 39. There are provided a plurality of L-shaped tubes 40 to be fed inside.

Next, the oxygen gas flow paths of the metal lances 10 and 30 will be examined.
The oxygen gas flow path of the bullion cutting lance 10 includes an oxygen delivery path 16, an intermediate flow path 22, and a plurality of oxygen discharge holes 23. When the plurality of oxygen discharge holes 23 are treated as one, the flow path is It can be schematically shown as in FIG. As shown in FIG. 6A, the cross-sectional area of the flow path is constant in the oxygen delivery path 16 along the oxygen gas traveling direction, and is small at the point where the oxygen delivery path 16 is switched to the intermediate flow path 22. Thus, the pressure gradually decreases in the intermediate flow path 22, decreases at the location where the intermediate flow path 22 switches to the oxygen discharge hole 23, and is constant in the oxygen discharge hole 23. In the region where the cross-sectional area of the flow path gradually decreases, it is known that the pressure loss generated with respect to the fluid is negligible. Therefore, in the metal cutting lance 10, the oxygen delivery path 16 substantially passes from the oxygen delivery path 16 to the intermediate flow path 22. Pressure loss will occur in the oxygen gas only at the location where it switches, the location where it switches from the intermediate flow path 22 to the oxygen discharge hole 23, and the location where it blows out from the opening 12.

The oxygen gas flow path of the bullion cutting lance 30 includes an oxygen delivery path 32, intermediate flow paths 35, and a plurality of oxygen discharge holes 36. When the plurality of oxygen discharge holes 36 are handled as a whole, the flow path is It can be schematically shown as 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 oxygen gas traveling direction, and suddenly changes at the point where the oxygen delivery path 32 switches to the intermediate flow path 35. , And is enlarged at the intermediate flow path 35, reduced at the location where the intermediate flow path 32 switches to the oxygen discharge hole 36, and constant at the oxygen discharge hole 36.
That is, since the cross-sectional area is once suddenly reduced at the location where the oxygen delivery path 16 of the bullion cutting lance 30 is switched from the intermediate flow path 35 and then rapidly expanded, a large pressure loss is caused. The resulting pressure loss is greater for the metal cutting lance 30 than for the metal 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, 3 (A), and (B) and the bullion cutting lance 30 shown in FIGS. The cutting lance 30 had a loss factor ζ ₁ = 2.3 to 2.5, whereas the bare metal lance 10 had a loss factor ζ 2 = 0.04, reducing pressure loss 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 and the like that do not depart from the gist are within the scope of the present invention.
For example, the intermediate flow path only needs to have a cross-sectional area that gradually decreases from one side (upstream side) to the other side (downstream side). The direction length (height) need not be reduced.
Further, the oxygen discharge holes do not need to be arranged in the circumferential direction at the same position in the axial direction of the metal cutting lance, and may be arranged, for example, at different positions in the axial direction of the metal cutting lance. Furthermore, the oxygen discharge hole does not have to be circular in cross section.

10: Metal cutting lance, 11: Side wall, 12: Opening, 13: Converter, 14: Furnace, 15: Partition material, 15a: Insole, 15b: Partition material, 16: Oxygen delivery path, 17: Cooling water Outward path, 18: Cooling water return path, 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 forward path, 34: Cooling water return path, 35: Intermediate flow path, 36: Oxygen discharge hole, 37: Opening, 38: Bottom plate, 39: Bottom space, 40: tube, G: direction of blowing oxygen gas, P: bare metal

Claims (2)

In a bullion cutting lance that is formed in a bottomed cylindrical shape, blows oxygen gas into the converter from a plurality of openings provided on the side wall on the tip side, and removes the bullion attached to the periphery of the furnace port,
An oxygen delivery path disposed along the axis at a position inside the side wall and at a distance from the side wall, and one side communicates with the oxygen delivery path and sends oxygen gas from the oxygen delivery path to the other side The intermediate flow path includes a plurality of oxygen discharge holes each having one side communicating with the other side of the intermediate flow path and the other side communicating with the openings, and the intermediate flow path is directed from one side to the other side. A bullion cutting lance characterized in that the cross-sectional area gradually decreases. The plurality of oxygen discharge holes are arranged in the circumferential direction, and the length of the intermediate flow path in the axial direction of the bullion cutting lance of the cross section decreases from one side to the other side. The bullion cutting lance according to claim 1.

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