JP3480354B2 - Tundish heating device - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a heating device for a tundish of a continuous casting machine.

[0002]

2. Description of the Related Art Generally, a tundish for distributing molten steel after refining to a mold is used to secure a casting temperature of the molten steel.
It is preheated before casting by a gas burner provided on the preheating cover above it. This preheating is performed by mixing 110-120% of the theoretical air amount with fuel gas such as coke oven gas and burning it in the tundish, whereby the inner surface of the tundish is heated to 1200-1300 ° C. . Therefore, when the used tundish with residual steel and residue is reused, such residual steel and residue are oxidized by preheating, and the oxides generated at that time are taken into the molten steel and deteriorate the quality of the slab.

Therefore, in order to prevent the oxidation of residual steel and slag, Japanese Patent Laid-Open No. 4-22567 discloses a method of reducing the amount of air supplied to a preheating gas burner to 70 to 100% of the theoretical amount of air. Further, Japanese Patent Application Laid-Open No. 2-37949 proposes a method of substituting Ar in a gas burner or a tundish immediately after preheating.

However, since such a method cannot completely prevent the oxidation of the residual steel and the slag, JP-A-8-159664 discloses that a plurality of heat storage type preheaters are provided on the upper part of the tundish, and the heat storage of each preheater A method is disclosed in which an inert gas is alternately passed through the body and a heated high-temperature inert gas is continuously supplied into the tundish to perform non-oxidative heating.

[0005]

SUMMARY OF THE INVENTION
In the method described in the 8-159664 publication, the oxidation of the residual steel and the residue can be completely prevented, but the heating efficiency is higher than that of the combustion gas having thermal radiative property because the non-thermal radiative inert gas is used. It is remarkably inferior and becomes extremely inefficient when pre-heating an unused new tundish that has no residual steel or residue and does not require non-oxidative heating.

The present invention has been made in order to solve such problems, and it is possible to completely prevent the oxidation of the residual steel and the residue with respect to the used tundish, and with respect to the unused tundish. Aims to provide a tundish heating device capable of heating with high efficiency.

[0007]

The above-mentioned problems are provided with a plurality of regenerative heating devices for supplying a high temperature inert gas into the tundish and a plurality of gas burners for supplying a combustion gas into the tundish. This is solved by a heating device of a tundish controlled so that the supply of the high temperature inert gas and the supply of the combustion gas are performed independently.

[0008] A plurality of regenerative heating devices capable of supplying a high temperature inert gas into the tundish and a plurality of gas burners capable of supplying a combustion gas into the tundish, and supply of the high temperature inert gas If the combustion gas is controlled to be supplied independently, it is possible to heat only the used tundish by alternately supplying high temperature inert gas from multiple heat storage heating devices, and to burn the combustion gas. By supplying from multiple gas burners alternately, only the unused tundish can be heated. Therefore, since the used tundish can be heated without oxidation, it is possible to completely prevent the oxidation of the residual steel and the dregs and to heat the unused tundish with high efficiency.

If the air for combustion is supplied through the heat storage body of the heat storage type heating device, the high temperature air can be supplied, so that the combustion can be performed with higher thermal efficiency.

If the combustion gas after heating the tundish is released to the outside through the heat storage body of the heat storage type heating device, the heat can be effectively used.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an embodiment of the invention of a tundish heating apparatus according to the present invention.

This tundish heating device is provided on the upper part of the tundish 1, and has a gas burner 3 and a combustion chamber 4
Two heat storage type heating device 2 consisting of and heat storage body 5, and two machines provided on the wall surface of throat 6 for introducing high temperature inert gas supplied from each heat storage type heating device 2 into tundish 1. Gas burner 7 and fuel gas, inert gas,
Pipes 10, 20, 30, 40 for supplying air to the gas burner 3 and the gas burner 7 of the heat storage type heating device 2, and on-off valves 11, 12, 13, 14, 15, 16, for turning on / off the supply. 21, 22,
23, 31, switching valve 41 for switching the type of supply gas, exhaust pipe 50 for exhausting combustion gas, exhaust fan 51, regenerative heating device 2, gas burner 7, on-off valves 11, 12, 13, 14 , 1
5, 16, 21, 22, 23, 31 and a control device (not shown) for the switching valve 41, and the heat storage type heating device 2 having two high-temperature inert gases as described below. Used tundish 1 that was alternately supplied from
Combustion gas is alternately supplied from two gas burners 7 to heat the unused tundish 1.

First, a method for alternately supplying a high temperature inert gas from two heat storage type heating devices 2 to the tundish 1 will be described.

1. The valve 11 provided in the pipe 10 for supplying the fuel gas is opened, and the valve 12 and the valve 13 at the tip of the valve 11 are alternately opened and closed at a time interval of several tens of seconds to one hundred and several tens of seconds. Fuel gas is alternately supplied to the gas burner 3 of the heat storage type heating device 2. At this time, the valve 14 is closed so that the fuel gas is not supplied to the gas burner 7. A valve provided in the pipe 20 for supplying air to match the supply of fuel gas
21 and valve 22 are opened and closed in conjunction with opening and closing of valve 12 and valve 13,
Air is alternately supplied to the gas burner 3 of the heat storage type heating device 2 of the table. The fuel gas supplied to the gas burner 3 of the heat storage type heating device 2 is jetted into the combustion chamber 4 while being heated together with air, and is mixed with air in the combustion chamber 4 and burned. Such combustion is alternately performed in the combustion chambers 4 of the two regenerative heating devices 2.

2. The combustion gas generated in the combustion chamber 4 is the heat storage body 5
The heat is stored in the heat storage body 5 to radiate the sensible heat there. The combustion gas radiated by the heat storage body 5 is sent to the exhaust pipe 50 through the pipe 40 and the switching valve 41, sucked by the exhaust fan 51 and discharged to the outside.

3. When combustion is alternately occurring in the combustion chambers 4 of the two heat storage type heating devices 2, the valve 31 provided in the pipe 30 for supplying the inert gas is opened, and the switching valve 41 An inert gas is supplied to the heat storage body 5 of the heat storage type heating device 2 of which combustion is completed via the pipe 40. The supplied inert gas is the heat storage body 5
It is heated in the tundish through the combustion chamber 4 and throat 6.
Sent into 1. Since the tundish 1 is heated by a high temperature inert gas, it is subjected to non-oxidative heating and completely prevents the oxidation of the residual steel and the slag. At this time, the inert gas is the switching valve.
The tundish 1 is continuously heated because it is alternately supplied to the heat storage bodies 5 of the two heat storage type heating devices 2 by using 41.

After heating the tundish 1, the inert gas is discharged from the opening of the molten steel nozzle 8 to the outside.

Next, a method of alternately supplying the combustion gas from the two gas burners 7 to the tundish 1 will be described.

1. The valve 11 for supplying the fuel gas to the gas burner 3 of the heat storage type heating device 2 is closed, the valve 14 for supplying the fuel gas to the gas burner 7 is opened, and the valves 15 and 16 at the tip of the valve 14 are opened. The fuel gas is alternately supplied to the two gas burners 7 by alternately opening and closing at a time interval of several tens of seconds to one hundred and several tens of seconds.
At the same time, the valves 21 and 22 for supplying air to the gas burner 3 of the regenerative heating device 2 are closed, and the throats 6 at the two locations are closed.
The valve 23 for supplying air is opened, the switching valve 41 is switched according to the opening and closing of the fuel gas supplying valves 15 and 16, and the air is alternately supplied to the two throats 6. At this time, after passing through the switching valve 41, the air is supplied to the throat 6 through the pipe 40, the heat storage body 5 of the heat storage heating device 2, and the combustion chamber 4. Further, since the air is heated by the heat storage body 5, the subsequent combustion in the throat 6 is efficiently performed.

2. The fuel gas supplied to the gas burner 7 is jetted to the throat 6 while being heated, mixed with air at the throat 6 and sent into the tundish 1 while being burned. Since the tundish 1 is heated by the combustion gas having a high heat radiation property at a high temperature, the unused tundish 1 can be heated with high efficiency. Further, since such heating is alternately performed by the two gas burners 7, the tundish 1 can be continuously heated.

After the tundish 1 is heated, the combustion gas having a high sensible heat is heated from the throat 6 which is not burned to the heat storage body 5 of the heat storage type heating device 2 above the throat 6.
The heat is stored in the heat storage body 5, and after being radiated by the heat storage body 5, the heat is discharged to the outside through the pipe 40, the switching valve 41, the exhaust pipe 50, and the exhaust fan 51. Therefore,
Effective use of heat is achieved.

All the above operations are automatically performed by the control device. In fact, by the tundish heating device that uses both the non-oxidative heating by the high temperature inert gas and the heating by the combustion gas shown in FIG. 1 and only the non-oxidative heating by the inert gas described in JP-A-8-159664. Use the tundish heating device to remove unused tundish from 1200
The heating time until heating up to ℃ and the cumulative fuel consumption are
In the case of non-oxidizing heating described in JP-A-8-159664,
When determined by the ratio as 1, when heating with a combustion gas in the heating device of the present invention as shown in Table 1, compared with the case of non-oxidative heating using nitrogen as an inert gas, heating time, fuel It was found that both consumption could be reduced to 1/4.

[0023]

【table 1】

[0024]

Since the present invention is constructed as described above, it is possible to completely prevent the oxidation of the residual steel and the residue with respect to the used tundish, and with respect to the unused tundish. A tundish heating device capable of heating with high efficiency can be provided.

[Brief description of drawings]

FIG. 1 is a view showing an embodiment of the invention of a tundish heating apparatus according to the present invention.

[Explanation of symbols]

1 tundish 2 Heat storage type heating device 3 Gas burner (for heat storage type heating device) 4 Combustion chamber 5 Heat storage 6 throat 7 gas burner 8 Molten steel nozzle 10 piping (for fuel) 11 valves (for fuel) 12 valves (for fuel) 13 valves (for fuel) 14 valves (for fuel) 15 valves (for fuel) 16 valves (for fuel) 20 piping (for air) 21 valves (for air) 22 valves (for air) 23 valves (for air) 30 piping (for inert gas) 31 valve (for inert gas) 40 piping 41 Switching valve 50 exhaust pipe 51 blower

─────────────────────────────────────────────────── ───Continued from the front page (56) Reference JP-A-10-185442 (JP, A) JP-A-9-295110 (JP, A) JP-A-10-237540 (JP, A) JP-A-10- 43844 (JP, A) JP 9-295127 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B22D 11/10 310 B22D 41/051

Claims (3)

(57) [Claims] 1. A heat storage type heating device for supplying a high temperature inert gas into a tundish, and a plurality of gas burners for supplying a combustion gas into the tundish, and further, supplying the high temperature inert gas. And a tundish heating device controlled so that the combustion gas is independently supplied. 2. The tundish heating device according to claim 1, wherein the combustion air is supplied through a heat storage body of the heat storage heating device. 3. The combustion gas after heating the tundish,
The heat is discharged to the outside via a heat storage body of the heat storage type heating device.
The heating device for a tundish according to claim 1 or claim 2.