JPH04162955A - Method and device for heating ladle - Google Patents

Abstract

PURPOSE:To uniformly execute heating for short time by shutting the opening part of a ladle, injecting hot blast at high speed diagonally downward from plural positions parted at the same interval to peripheral direction in peripheral edge of this opening part, reflecting at the bottom face and exhausting this from the intermediate positions to the peripheral direction at between the injecting position. CONSTITUTION:The opening part of ladle is shut with a shutting member 1, and the high speed hot blast is injected diagonally downward along the peripheral face of lining refractory from hot blast injecting pipes 5 in a high speed burners at plural positions parted at the same interval to the peripheral. direction in the peripheral edge of this opening part. At the same time, after ascending diagonally upward by reflecting the hot blast at the bottom face of lining refractory, this is exhausted from the exhaust holes 6 at the intermediate positions to the peripheral direction at between the above injecting positions. The high speed burner dilutes combustion gas burning gas or oil as fuel with excess air and the hot blast controlled to the necessary temp. is supplied in large quantity at high speed, and gas film on the boundary face is removed and heat transfer is remarkably improved to enable the quick heating. By this method, contact time with the lining refractory is increased and the heating can be uniformly executed for short time without the danger of explosion.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method and apparatus for heating a ladle for preheating and drying the refractory lining of the ladle.

[Conventional technology]

A ladle is a container used to transport molten metal from a furnace to a place of steelmaking or casting.For example, as shown in Fig. 4, a ladle is a cylindrical shell 11 with a bottom made of steel plate, and a refractory lining is placed on the inside of the shell 11. Thing 1
2, and a sliding nozzle 14 is attached to the bottom to take out molten steel 13. Steel mills use steel mills with a capacity of about 300 tons and steel mills with a capacity of about 100 tons.

In the figure, 15 is molten slag, and 16 is slag powder.

Before the ladle receives molten steel 13 from the converter or electric arc furnace, it is necessary to preheat the lining refractory 12 to a high temperature.

This means that if the lining refractory 12 is received without preheating,
The lining refractory 12 contacts the high-temperature molten steel 13 and its surface temperature rises rapidly, causing damage such as cracking, and the lining refractory 12 absorbs heat, causing the molten steel 1
This is because the temperature drop in step 3 becomes large, which adversely affects the next process of refining and continuous casting.

In addition, as the number of times the ladle increases, the inner refractory 12
is corroded and worn out by the molten steel 13 or molten slag 15, and its lining thickness decreases, making it unusable.
The lining refractory 12 needs to be relined, and relining and repairs are performed periodically.

Here, as the lining refractory 13, refractory bricks are used for most of the bottom wall 17 and the peripheral wall 18, or monolithic refractories such as castable refractories are used for a part or most of the peripheral wall 18. However, recent trends have seen the range of use of monolithic refractories being expanded due to reductions in lining costs, mechanization of construction, labor savings, etc.

Then, for the ladle where the relining and repair work of the lining refractory 12 has been completed, it is necessary to dry the lining refractory in order to remove moisture contained in the joint mortar of the refractory bricks used in construction or the monolithic refractory. There is.

Conventionally, preheating and drying of the ladle has been carried out by closing the opening of the ladle facing upward with a lid made of a steel shell 20 lined with a refractory lining 19, as shown in FIG. 5, for example. Hot air is ejected vertically downward from the center of the lid toward the center of the bottom wall 17 by one high-speed burner 21, and is diverted to the surroundings along the bottom wall surface as shown by the dashed line in the same figure. , a method of raising the gas along the peripheral wall surface and discharging it from a plurality of exhaust ports 22 provided at the peripheral edge of the lid while circulating part of it along the lining refractory 19 of the lid, or as shown in FIG. As shown in FIG. As shown in , the flow is diverted upward along the bottom wall surface, horizontally diverted toward the lid along the peripheral wall surface, and a portion is circulated along the refractory lining 19 of the lid, Exhaust hole 2 provided on the upper periphery of the lid
A method of discharging from 2' is used.

[Problem to be solved by the invention]

However, in the conventional heating method described above, since the ladle is shaped like a container with an opening in one direction, it is difficult to uniformly heat the entire refractory lining, and the inner refractory may be heated rapidly or locally. damage the refractory bricks,
This causes various adverse effects such as abnormal expansion, deformation, and explosion of the castable refractory. Moreover, as the range of use of castable refractories that use a large amount of construction water compared to refractory bricks increases, it becomes more difficult to use and requires a long time to heat.

Incidentally, if the steel is received with insufficient drying and preheating after construction, the high temperature molten steel will come into contact with residual moisture, explosively generating moisture and damaging the lining refractories, and hydrogen gas may be released into the molten steel. Encapsulation causes serious quality deterioration.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a method and apparatus for heating a ladle that can heat the ladle uniformly and in a short time.

[Means to solve the problem]

In order to solve the above problems, the ladle heating method of the present invention includes:
The opening of the ladle facing upward is closed, and high-speed hot air is applied diagonally downward in the same direction along the circumferential surface of the refractory lining of the ladle from multiple points equally spaced apart in the circumferential direction of the periphery of this opening. This is a method in which the hot air is ejected from the bottom surface of the refractory lining, and then raised diagonally upward along the circumferential surface of the refractory lining, and then discharged from an intermediate location in the circumferential direction between the hot air jetting locations. .

In addition, the ladle heating device is attached to a closing member that closes the opening of the ladle facing upward, and to multiple locations equidistantly spaced in the circumferential direction of the closing member corresponding to the periphery of the opening. A high-speed burner that blows hot air diagonally downward in the same direction along the circumferential surface of the refractory lining of the ladle, and an exhaust port that is located in the middle of the circumferential direction between the mounting positions of the high-speed burner and provided in the closing member. It is what it is.

[Effect]

In the above-mentioned means, high-speed hot air is ventilated along the circumferential surface of the lining refractory in the ladle so as to draw a parabola at a plurality of locations.

High-speed hot air means a speed of 80 to 2001 I/s, a speed of 100 to
A high-velocity burner refers to one with a temperature of 1000°C, and a high-velocity burner is a burner that dilutes the combustion gas of gas or oil as fuel with excess air and blows hot air at a high speed with a controlled temperature. It is supplied in large quantities, and when the high-speed hot air collides with the object to be heated, the gas film at the interface is removed and the high-speed hot air comes into direct contact with the object to be heated, greatly improving heat transfer and rapid heating. It is possible.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings. In the following description, the same components as in FIG. 4 are designated by the same reference numerals, and the description thereof will be omitted.

FIGS. 1 and 2 are a plan view and a longitudinal sectional view showing an embodiment of a ladle heating device.

In the figure, reference numeral 1 denotes a closing member that closes the opening of the ladle facing upward, and is composed of an outer skin 2 made of a steel plate and a refractory lining 3 lined on the back side of the outer skin 2. A pedestal (not shown) is screwed on. Three injection tube insertion holes 4 are spaced at equal intervals in the circumferential direction at positions corresponding to the periphery of the opening of the ladle in the closing member 1, and
It is provided to penetrate diagonally downward in the same direction (clockwise direction in FIG. 1) along the circumferential surface of the refractory lining 2 of the ladle (see FIG. 3). A hot air jetting pipe 5 of a high-speed burner that jets high-speed hot air is inserted into each jetting pipe insertion hole 4. In addition, three exhaust ports 6 are provided at positions corresponding to the periphery of the opening of the ladle in the closing member 1.
It is located midway between the two.

To preheat or dry the ladle using the ladle heating device configured as described above, as shown in FIG. 2, after closing the opening of the ladle facing upward with the closing member 1, Hot air is ejected from the hot air ejection pipe 5. Each hot air jet pipe 5
The main flow of hot air blown out from the ladle descends obliquely downward in the same direction along the peripheral wall 18 of the lining refractory 12 in the ladle, as shown by the dashed line in FIGS. 1 and 2, and then reaches the bottom. It is reversed by the wall part 17 and raised diagonally upward again along the peripheral wall part 18, and is ventilated so to speak in a parabola at a plurality of locations, and is discharged from the respective exhaust ports 6. Further, a part of the hot air is influenced by the hot air from other jet ports, becomes a turbulent flow or a circulating flow, performs a stirring action, and is then discharged from the exhaust port 6.

Therefore, compared to the conventional method, the contact time with the lining refractory 3 is increased, and uniform heating is performed while preventing the occurrence of explosions and the like.

The high-speed burner is operated by starting heating with a large amount of high-speed dilution air supplied to lower the hot air temperature, and gradually increasing the hot air temperature while decreasing the amount of dilution air.

Here, the output of the high-speed burner is 1.2 million kcal/hr.
, a large-scale steelworks steel mill, which was repaired at an angle of inclination of 15 degrees to the perpendicular, using coke oven gas as fuel, and using approximately 15 tons of refractory bricks and mortar, and a lining of approximately 30 tons of castable refractories. Ladle (outer diameter approx. 4500-
The drying time, explosiveness, etc., were as shown in Table 1, which also shows the drying results using the conventional equipment shown in Figure 5. .

According to Table 1, it can be seen that the product of the present invention can shorten the drying time, prevent explosions, and reduce the difference in temperature distribution within the ladle.

In addition, in the above-mentioned example, the case where three high-speed burners were used was described, but the case is not limited to this. 2 high-speed burners depending on the usage ratio etc.
It may be one group or four or more groups.

Heating is of course not limited to drying after reupholstering and repair work, but may also be performed for drying or preheating a new pot that has been completely reupholstered.

〔Effect of the invention〕

As described above, according to the present invention, high-speed hot air is ventilated in a parabolic manner at multiple locations along the circumferential surface of the refractory lining in the ladle, so that the distance between the refractory lining and the refractory lining is greater than in the past. The contact time is increased and the heating can be done uniformly and without detonation and in a short time.

[Brief explanation of drawings]

1 to 3 show an embodiment of the present invention, FIG. 1 is a plan view of a ladle heating device, and FIG. 2 is a plan view of the ladle heating device, and FIG.
3 is an enlarged sectional view taken along the line ■-■ in FIG. 1, FIG. 4 is a longitudinal sectional view of a normal ladle, and FIGS. 5 and 6 are longitudinal sectional views of conventional techniques, respectively. . 1... Closing member 4... Outlet tube insertion hole 5.
...Hot air jet pipe 6...Exhaust port Applicant: Yujibe Taka, Patent Attorney, Tosera Engineering Co., Ltd. = Bonito. :Ball;- I:r and work Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6

Claims (2)

[Claims] (1) Close the opening of the ladle facing upwards, and blow high-speed hot air in the same direction along the circumferential surface of the refractory lining of the ladle from multiple locations equally spaced apart in the circumferential direction of the periphery of this opening. The hot air is ejected diagonally downward, at the same time as it is reversed at the bottom of the refractory lining and raised diagonally upward along the circumferential surface of the refractory lining, and then discharged from an intermediate location in the circumferential direction between the hot air jetting locations. A method of heating a ladle characterized by the following. (2) A closing member that closes the opening of the ladle facing upward, and a closing member that is attached to multiple points equally spaced apart in the circumferential direction of the closing member corresponding to the periphery of the opening, and is installed to blow high-speed hot air inside the ladle. It is characterized by consisting of a high-speed burner that blows out diagonally downward in the same direction along the circumferential surface of the refractory, and an exhaust port that is located in the circumferential middle between the mounting positions of the high-speed burner and is provided in the closing member. Ladle heating device.