JP3088558B2 - Vacuum degassing tank heating device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for heating the inside of a vacuum degassing tank using a high-temperature combustion flame.

[0002]

2. Description of the Related Art For example, gaseous impurities are removed by subjecting molten steel to vacuum degassing, or carbon in steel is reduced to carbon.
It is known that the gas is released as O gas to produce ultra-low carbon steel. As a mode of the vacuum degassing process, for example, a so-called RH type vacuum degassing device that refines in a process of circulating molten steel in a ladle in a vacuum degassing tank, or a process of sucking up and discharging molten steel. A so-called DH vacuum degassing apparatus for refining is used.

[0003] In order to minimize the decrease in the temperature of molten steel during the vacuum degassing process, it has been practiced to preheat the inside of the vacuum degassing tank in advance. Also, in the process of the vacuum degassing process, a splash occurs when bubbles in the molten steel separate from the molten steel interface, and the droplets of the molten steel fly when the molten steel droplets or the molten steel float on the surface of the molten steel. I do. These droplets adhere to the inner wall of the vacuum degassing tank and vary depending on the height of the vacuum degassing tank.
Since it is remarkably deposited in a range of 0 mm, it is practiced to dissolve and remove by heating.

Various types of heating devices are used as a preheating device in the vacuum degassing tank or a device for dissolving and removing metal, etc., for example, an electrode heating device capable of heating even during the vacuum degassing process, and a burner after the vacuum degassing process. A device for heating with a combustion flame has been proposed. As a specific device using a burner combustion flame, for example, as proposed in Japanese Patent Publication No. 45-31062, a burner is arranged at the lower end of an immersion pipe provided at the lower part of a vacuum degassing tank, An exhaust port is provided at the upper part of the vacuum degassing tank, and the combustion flame flows upward from the lower part to preheat the inside of the vacuum degassing tank. Also, Japanese Patent Application Laid-Open No. 01-159212
As proposed in the publication, a burner inserted at the top of the vacuum degassing tank and the combustion gas are distributed to both the exhaust flue provided on the upper side surface of the vacuum degassing tank and the dip tube provided at the lower part. There are known devices for preheating and dissolving and removing adhered metal in a vacuum degassing tank composed of a damper provided in an exhaust duct for performing the operation, and a bypass duct connecting an immersion pipe and the exhaust duct.

[0005]

SUMMARY OF THE INVENTION The above Japanese Patent Publication No. 45-31
According to the preheating apparatus disclosed in Japanese Patent No. 062, the combustion flame is generated in the immersion pipe portion having a relatively small inner diameter. Therefore, when a high-temperature combustion flame is used, only the immersion pipe portion locally becomes high in temperature, resulting in excessive preheating. Is inherent. Further, it is difficult to prevent air from entering from the gap between the immersion pipe and the burner, and the infiltration air is interposed between the combustion flame and the inner wall, so that the heating efficiency is not good. For example, the temperature in the vacuum degassing tank is only about 800 to 1000 ° C. Can't preheat.

[0006] The heating device disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 01-159212 can generate a high-temperature combustion flame because a combustion flame is generated in a vacuum degassing tank. Since it is distributed to both the exhaust flue provided and the immersion pipe provided at the lower part, the auxiliary equipment provided in the exhaust flue connected to the vacuum system must be heat-resistant or the temperature of the passing gas must be lowered. Is required. Also, since the supplied combustion energy is divided into two parts, the heating efficiency is reduced and the heating time is prolonged. Therefore, in order to meet the vacuum degassing schedule, the combustion temperature control by the damper and the strict division control of the combustion gas are required. Is required.

The present invention provides a heating device for a vacuum degassing tank to which a high-temperature combustion flame generating and heating burner having good heat-releasing efficiency, which solves the problems inherent in the above prior art, is applied.

[0008]

According to the present invention, the vicinity of the connection of an exhaust duct connected to a vacuum degassing tank is closed by a water-cooling shut-off plate, and a plurality of pure carbon burners are provided at the top of the vacuum degassing tank. Are arranged in an annular shape, and a heating burner configured by providing a secondary combustion air supply passage at the center thereof is inserted and installed so as to be able to move up and down freely, and a lifting drive device is provided at the upper end of the heating burner. Heating device for the vacuum degassing tank,
Further, the outer periphery of the heating burner has a water-cooled structure,
And a heating device for a vacuum degassing tank provided with a heating burner in an elevating drive device comprising a multi-stage elevating guide, and a dolly capable of moving up and down the melting metal receiving container below the immersion pipe of the vacuum degassing tank. And a lid member provided with an exhaust duct and a tubular member matching the immersion pipe is placed on the upper surface of the container, and the other end of the exhaust duct is located downstream of the exhaust duct closed by the water-cooling shut-off plate. It is a heating device for the vacuum degassing tank connected to the side.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below based on embodiments shown in the drawings. 1 (a) and 1 (b) are schematic explanatory views of a heating device for a vacuum degassing tank according to the present invention.
Separates a flange 3 provided in the vicinity of a connection portion of an exhaust duct 2 connected to a vacuum degassing tank 1 having completed a vacuum degassing process, and interposes a water-cooled shut-off plate 4 between the flanges 3. Then, the flow path of the exhaust duct 2 is shut off. Since the junction of the exhaust duct 2 of the vacuum degassing tank 1 is heated to about 1000 ° C. or more during a heat treatment described later, the shut-off plate 4 has a water-cooled structure.

At the top 5 of the vacuum degassing tank 1, a heating burner 6 is inserted so as to be vertically movable. In this state,
In the vacuum degassing tank 1, the immersion pipe 7 provided at the lower part of the tank is opened, and the other parts are substantially closed.
The outflow path of the combustion gas during the heat treatment described later is only the immersion pipe 7.

The heating burner 6 is, as shown in FIG.
A plurality of pure oxygen burners 8 are annularly arranged at the tip, and an air supply hole 9 for secondary combustion is provided at the center. The pure oxygen burner 8 is connected to a supply source by a combustion supply line 10 and a pure oxygen supply line 11. The air supply hole 9 is connected to a supply source by an air supply pipe 12.

When a fuel supplied when the pure oxygen burner 8 is ignited, for example, a high calorie gas such as a coke oven gas, a short flame having a surface temperature of about 1800 to 2000 ° C. is obtained. When a predetermined amount of secondary combustion air is supplied from the center of the combustion flame, a long flame corresponding to the air supply amount can be obtained without changing the flame surface temperature. Therefore, the purpose of heating the vacuum degassing tank, for example, heating for dissolving and removing adhered metal, heating for preheating the inner wall of the tank,
The characteristics of the combustion flame can be selected and applied according to the heating for drying the inner wall after the repair.

Since the heating burner 6 is held in the vacuum degassing tank 1 heated to about 1000 ° C. or more for a relatively long time, a water cooling jacket 13 is provided on the outer peripheral surface thereof, and the water cooling jacket 13 is covered with the water cooling jacket 13. Pipelines 14 and 15 for supplying and discharging cooling water are connected.

The heating burner 6 is mounted on a lifting drive 16. As shown in FIG.
Is provided with a sliding guide 18 slidable up and down on a fixed guide 17, a heating burner 6 is slidably provided on the sliding guide 18, and an elevating wire 19 is connected to the upper end of the heating burner 6. , The other end of the wire 19 is wound up and rewinded 2
It is configured by connecting to 0. Since the heating burner is raised and lowered along this multi-stage lifting guide, the lifting and lowering is smooth, and the setting of the lifting distance is not only accurate, but also in existing equipment,
Even when there is not enough room in the height direction, a large stroke can be secured.

At the time of the heating treatment of the vacuum degassing tank, a heating flame is ignited to form a combustion flame which has reached a heating purpose.
When the inside of the vacuum degassing tank is heated by appropriately selecting the height position of the heating flame, the combustion flame intensively heats a specific portion, for example, a portion with a large amount of metal, so that the metal can be dissolved and removed. At the same time, the flue gas fills the vacuum degassing tank and preheats other parts, and excess flue gas flows out of the dip tube.

[0016] The radiation and heat transfer loss of the immersion tube portion are suppressed,
As means for suppressing the infiltration air, as shown in FIG. 1B, a molten metal receiving container 21 is disposed on a dolly 22 capable of moving up and down and running below the immersion pipe 7. A lid member 25 provided with a cylindrical member 23 and an exhaust duct 24 corresponding to the immersion pipe 7 is placed on the downstream side of the exhaust duct 2 closed by the water-cooling shut-off plate 4. It is preferable to use a heating device for a connected vacuum degassing tank.
According to the method of bypassing the combustion flame to the exhaust duct 2, the temperature of the combustion exhaust gas passing through the exhaust duct 23 is 900 ° C.
Since it has sensible heat before and after, a refractory lining is provided in the path. By performing the above-described exhaust bypass heating, the immersion pipe 7 can be heated to a higher temperature, so that spalling of the refractory is reduced and the life of the immersion pipe is extended.

[0017]

The heating device for a vacuum degassing tank of the present invention uses a heating burner which is constituted by arranging a plurality of pure oxygen burners in an annular shape and providing a secondary combustion air supply passage at the center thereof. The characteristics of the combustion flame are selected and applied according to the mode of heating of the vacuum degassing tank, specifically, heating for dissolving and removing adhered metal, heating for preheating the inner wall of the tank, and heating for drying the inner wall after repair. can do. In addition, since the heating burner is provided in the lifting drive device, the combustion flame having the characteristics corresponding to the heating purpose can be accurately set at the optimum position.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view of a heating device for a vacuum degassing tank according to the present invention.

FIG. 2 is a schematic explanatory view of a heating burner used in the present invention.

FIG. 3 is a schematic explanatory view of a lifting / lowering drive device of a heating burner used in the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vacuum degassing tank 2 Exhaust duct 3 Flange 4 Water cooling shutoff plate 5 Top of vacuum degassing tank 6 Heating burner 7 Immersion pipe 8 Pure oxygen burner 9 Secondary combustion air supply hole 10 Fuel supply line 11 Pure oxygen supply tube Path 12 Air supply line 13 Water cooling jacket 14, 15 Cooling water supply / drainage line 16 Elevating drive device 17 Fixed guide 18 Sliding guide 19 Wire rope 20 Winding and rewinding device 21 Melting metal receiving device 22 Elevating and traveling freely Truck 23 Cylindrical member 24 Exhaust duct 25 Lid member

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Tadashi Imai 5-3 Tokai-cho, Tokai-shi, Aichi Prefecture Nippon Steel Corporation Nagoya Works (58) Field surveyed (Int. Cl. ⁷ , DB name) C21C 7/10 C22B 1/20

Claims (4)

(57) [Claims] 1. A portion near the connection of an exhaust duct connected to a vacuum degassing tank is closed by a water-cooling shut-off plate, and a plurality of pure oxygen burners are annularly arranged at the top of the vacuum degassing tank. Heating a burner, which is provided with a secondary combustion air supply passage in its section, so as to be vertically movable, and a lifting drive device is provided at the upper end of the heating burner. apparatus. 2. The heating device for a vacuum degassing tank according to claim 1, wherein an outer peripheral portion of the heating burner has a water cooling structure. 3. The heating device for a vacuum degassing tank according to claim 1, wherein the heating burner is provided in a lifting drive device comprising a multi-stage lifting guide. 4. A dissolving metal receiving container is disposed on a dolly capable of moving up and down and under a dipping tube of a vacuum degassing tank, and a cylindrical member exhaust duct corresponding to the dipping tube is provided on an upper surface of the container. 4. The heating device for a vacuum degassing tank according to claim 1, wherein the provided lid member is placed, and the other end of the exhaust duct is connected to a downstream side of the exhaust duct closed by a water-cooling shutoff plate.