JP2003146712A - Cooling method for granulation equipment of molten slag - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cooling method for a granulation equipment of molten slag by which the cooling efficiency for the blades of a rotary drum is improved to suppress the wear thereof, so that the frequency of exchanging the blades can be reduced, and the productivity in molten slag treatment equipment can be improved. SOLUTION: In the cooling method for the granulation equipment of molten slag where molten slag 12 discharged from a refining furnace is flowed down to blades 17 and 18 radially fitted to high speed rotary bodies 19 and 20 to granulate the molten slag 12, cooling water is sprayed from a plurality of spray nozzles 27a and 28a arranged so as to be directed to the high speed rotary bodies 19 and 20 and the blades 17 and 18, and the high speed rotary bodies 19 and 20 and the blades 17 and 18 are cooled.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to cooling a molten slag granulating facility for producing granular slag by shearing and scattering the molten slag discharged from a refining furnace using a blade attached to the outer periphery of a high-speed rotating body. Regarding the method.

[0002]

2. Description of the Related Art Conventionally, when molten steel is smelted in a refining furnace such as a converter or an electric furnace, molten slag of 80 to 180 kg / ton molten steel per unit weight of molten steel is produced. This molten slag is normally discharged into the soil and gradually cooled by natural cooling, and then used as a civil engineering material such as a roadbed material or caisson filling material. However, in the case of the method of discharging into the soil,
A large site is required, dust is generated during the process, and high heat work is required, which deteriorates the work environment and the surrounding environment.
To prevent this deterioration of the environment, Japanese Patent Publication No. 58-1713
As described in Japanese Patent Publication No. 6 and Japanese Patent Publication No. 7-96458, the molten slag is scattered by the blades provided on the outer periphery of the high-speed rotating body, and spray water is sprayed in the recovery box to granulate the slag. The method of quenching is done. This method has the advantage that the slag treatment can be performed in a compact facility, the site area is small, and the environment for hot work and dust can be improved. Furthermore, since the slag can be rapidly cooled, 2CaO.SiO ₂ (dicalcium silicate) with a large volume expansion present in the slag can be converted into a β phase with a small volume change, and slag pulverization can be prevented. It also has the great advantage that The high-speed rotating body used in this slag treatment equipment consists of a straight drum cylindrical rotating drum, and by rotating the rotating drum by a drive system, and rotating a plurality of blades radially attached to the outer periphery of the rotating drum. , 1400-155
Molten slag having a high temperature of 0 ° C is scattered in the collection box. Therefore, an excessive heat load is applied to the blades, which causes deformation and wear due to a decrease in the strength of the blades, and slag adhering to the blades and the rotating drum falls and accumulates on the lower part of the rotating drum. There is a problem that the work load increases due to the removal.

[0003]

[Problems to be Solved by the Invention] Japanese Patent Publication No. 58-1713
As described in Japanese Patent Publication No. 6 and Japanese Patent Publication No. 7-96458, when a cooling water channel is provided inside a metal blade and the blade is cooled from the inside, deformation wear and rotation due to the decrease in the strength of the blade described above. Problems such as accumulation of slag below the drum can be reduced. However, a large thermal gradient is generated in the blade thickness direction, and moreover, the thermal load is repeatedly changed,
There are cracks in the blades, and water leaks frequently from these cracks, and repairs such as overlay welding are frequently repeated, frequent replacement of blades increases equipment repair costs, and the operating rate of treatment equipment decreases. There's a problem.

The present invention has been made in view of the above circumstances, and it is possible to improve the cooling efficiency of blades of a high-speed rotating body to suppress wear, reduce the frequency of blade replacement, and improve the productivity of molten slag processing equipment. It is an object of the present invention to provide a method for cooling a molten slag granulation facility capable of achieving the above.

[0005]

According to the cooling method for molten slag granulating equipment of the present invention which meets the above object, the molten slag discharged from the refining furnace is made to flow down to a blade radially attached to a high-speed rotating body. In a method of cooling a molten slag granulating facility that granulates the molten slag, cooling water is sprayed from a plurality of spray nozzles arranged so as to orient the high speed rotor and the blade to cool the high speed rotor and the blade. To do. By this method, the blade surface is directly cooled, so that the cooling efficiency of the blade surface can be improved and the temperature rise can be minimized, and the generation and growth of minute cracks that occur on the blade surface can be prevented. can do. Furthermore, the blade immediately after the molten slag is sheared and scattered by the rotational force of the blade of the high-speed rotating body, the blade is cooled by spray water, and furthermore, a water film can be formed on the surface of the blade, and the molten slag and the blade are in contact with each other. When
Since the water adhered by the spray becomes steam and the molten slag can be instantly cut off from the surface of the blade and scattered, it is possible to prevent a decrease in the surface temperature of the blade and wear due to contact with the molten slag.

Here, the amount of cooling water sprayed from the spray nozzle is 2 per unit length in the axial direction of the high-speed rotating body.
It is recommended to set it to 0 to 500 liters / minute · m. As a result, the cooling efficiency of the surface of the blade can be stably increased, and the rise in the temperature of the surface of the blade can be suppressed to reliably prevent minute cracks and the like generated on the surface of the blade.
The amount of cooling water is a spray amount per minute per 1 m in the axial direction of the high-speed rotating body, and the amount of cooling water is 20 liters / minute.
If it is less than m, cooling of the blade of the high-speed rotating body is insufficient, the temperature of the surface of the blade rises, and blade wear and slag adhesion become remarkable. On the other hand, when it exceeds 500 liters / minute · m, the cooling effect is saturated even if the cooling water is sprayed, and the utility cost such as the water cost and the power cost of the water supply pump increases.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Next, referring to the attached drawings, an embodiment in which the present invention is embodied will be described to provide an understanding of the present invention. The present invention has conducted various tests to improve the cooling efficiency of blades radially attached to a high-speed rotating body in a granulation facility for molten slag having a processing capacity of 30 tons / hr, and as a result, it has been aimed at the blades of the high-speed rotating body. By arranging a plurality of spray nozzles that inject cooling water and directing the cooling water toward the blades from this spray nozzle, the blades of the high-speed rotating body can be efficiently cooled, and moreover, the slag to the blades We found that fusion and adhesion can be reduced,
Based on this knowledge, a cooling method for the molten slag granulation equipment was established.

FIG. 1 is an explanatory view of the molten slag granulating equipment applied to the cooling method of the molten slag granulating equipment according to one embodiment of the present invention, and FIG. 2 is a sectional view taken along the line AA of FIG. Figure, Figure 3
FIG. 4 is a schematic diagram showing a state of cooling water sprayed on the blades of a rotating drum. As shown in FIG. 1, a molten slag granulating facility 10 used in a method for cooling a molten slag granulating facility according to an embodiment of the present invention comprises a tubular rotary hood 1.
1, a gutter 14 for supplying molten slag 12 into the rotary hood 11 on the base side of the rotary hood 11.
And a drainage pan 13 for supplying the molten slag 12 to the gutter 14, and a screw conveyor 15 for discharging the granulated slag from the inside of the rotary hood 11 at the lower part on the front side of the rotary hood 11, and the rotary hood. 11
A chimney 16 for exhausting steam in the rotary hood 11 is provided at the center of the front side of the. Further, inside the rotary hood 11 located on the downstream side of the gutter 14, a plurality of blades 17 and 18, which are an example of a high-speed rotating body, are attached around the rotary hood 11, respectively, and two rotating drums 19 and 20 connected to a drive source are provided. Are arranged so that their axes are parallel to each other and are orthogonal to the longitudinal direction of the rotary hood 11. These rotary drums 19 and 20 have
Cooling water supply pipes 25a that communicate with cooling water pipes 25 that supply cooling water for cooling the insides of the rotating drums 19 and 20 are provided, and further, on both sides of the rotating drums 19 and 20 to communicate with a water supply pipe 26. Then, sprinkling pipes 23 and 24 respectively having a plurality of sprinkling spray holes 21 and 22 are arranged in the axial direction of the rotary hood 11. Further, as shown in FIGS. 1 and 2, below the rotary drums 19 and 20, water pipes 27 for spraying, which communicate with the water pipes 26 parallel to the shafts 19a and 20a of the rotary drums 19 and 20, respectively. Equipped with 28.

Further, as shown in FIGS. 2 and 3, in the water supply pipe 27 for spraying, there are provided a plurality of spray nozzles 27a in which the blades 17 radially attached to the rotary drum 19 are oriented.
In the water supply pipe 28 for spraying, a plurality of spray nozzles 2 having blades 18 radially attached to the rotary drum 20 are oriented.
8a are provided respectively. In addition, the rotary drums 19 and 2
The shafts 19a and 20a of 0 are the rotary drums 19 and 2 respectively.
0 drive transmission wheels 19b, 20 connected to the drive source on one side
b, bearings 19c are provided on both sides of the shafts 19a, 20a,
20c, and rotary joints 19d, 20d at one end of the shafts 19a, 20a.

Next, the cooling method of the molten slag granulating equipment according to one embodiment of the present invention will be described.
It will be described using 0. Molten slag 12 generated by decarburization refining in a refining furnace such as a converter or an electric furnace is discharged to a slag pan 13 and conveyed by a carrier truck, a crane or the like. 140
The high temperature molten slag 12 of 0 to 1550 ° C. is the slag pan 13
And is flowed down to the gutter 14 of the slag granulating equipment 10. At the same time, the blades 17 and 18 attached around the rotary drums 19 and 20 provided in the rotary hood 11 are rotated by operating the drive source, and the rotary drums 19 and 20 are rotated inside the shafts 19a and 20a. Cooling water is supplied from the cooling water supply pipe 25a communicating with the cooling water pipe 25 through rotary joints 19d and 20d, and the rotary drum 19
Cool the inside of 20. The molten slag 12 that has flowed down the gutter 14 is sheared and scattered by the rotational force of the blades 17 and 18, and the water is sprayed from the spray spray holes 21 and 22 of the spray pipes 23 and 24 communicating with the water supply pipe 26. It is sprayed onto and cooled to form granular slag. Then, the granular slag is removed from the rotary hood 1 by the screw conveyor 15 arranged behind the rotary hood 11.
1 out of 1. When the rotational speed of the rotary drums 19 and 20 is high, the centrifugal force is strong and the spray water is sprayed by the rotational force of the blades 17 and 18, while the rotational speed of the rotary drums 19 and 20 is low. Two
All of the molten slag 12 flowing down to 0 is not sheared and is welded to the blades 17 and 18 and the rotating drums 19 and 20, and the granulation ability is significantly reduced.
It is better to set it to 0 rpm.

Further, when the molten slag 12 is cooled, water vapor generated by vaporizing the sprinkled water is generated.
It is discharged from the chimney 16 provided on the front side of the rotary hood 11 to the outside of the system. Especially below the rotary drums 19 and 20,
Blades 1 radially attached to the rotating drums 19 and 20
Water supply pipe 27 for spraying, which is arranged with 7 and 18 oriented,
A plurality of spray nozzles 27a, 28a attached to the nozzle 28 sprays spray water on the surfaces of the blades 17, 18 to sufficiently cool the blades 17, 18. Since the spray water is sprayed by the spray nozzles 27a and 28a immediately after the molten slag 12 is sheared and scattered by the rotating force of the blades 17 and 18, the temperature rise of the metal constituting the blades 17 and 18 is minimized. You can stop at. Further, when the molten slag 12 comes into contact with the surfaces of the blades 17 and 18, the molten slag 12 is instantaneously transferred to the blades 17 and 18 by vaporization of a water film formed by spraying spray water from the spray nozzles 27a and 28a. It is possible to separate and scatter from the surface, suppress the welding phenomenon of the slag to the blades 17 and 18, prevent the slag from accumulating below the rotating drums 19 and 20, and simplify the work of removing the slag. . The spray water used for the spray nozzles 27a and 28a is preferably 20 to 500 liters / minute · m per unit length in the axial direction of the rotary drums 19 and 20.
If the spray water is less than 20 liters / minute · m, the amount of water required to cool the blades becomes insufficient, and the blade wear and the molten slag welding become remarkable. On the other hand, if it exceeds 500 liters / minute · m, the cooling effect is saturated, and the operating costs of water and pumps increase.

Further, the blade 1 is sprayed by spraying water.
It is possible to prevent an increase in the surface temperature of 7, 18 and wear due to contact with the molten slag 12. Moreover, the blade 17,
Since the heating by the molten slag 12 and the cooling by the spray water are repeated in the range of the extreme surface layer of 18, it is possible to prevent the progress of minute cracks generated on the surfaces of the blades 17, 18. As a result, the molten slag 1 of the blades 17 and 18
2 can surely prevent melting loss and wear, and
The life of the blades, the replacement frequency is reduced, the blades 17, 1
It is possible to avoid a steam explosion or the like caused by water leaking from 8. Also, the rotational force of the blades 17, 18 and the blades 17,
In order to scatter the molten slag 12 by utilizing the synergistic action of the peeling action due to the vaporization of the water film formed on the surface of 18,
Granular slag having particles of 5 mm or less can be obtained, and the slag having a small expandability can be obtained by the quenching effect of water.

Further, the rotary drums 19 and 20 and the blade 1
With respect to Nos. 7 and 18, in the conventional case, so-called internal cooling is performed to supply cooling water to the inside of the blade, but in the present embodiment, the internal cooling of the blade is not required, so the blade 1
Since the blades 7, 18 can be solid, the blades 17, 1
8 can be simplified in structure, and the blades 17, 18
A hose or the like for distributing the cooling water is not required inside, and the structure of the blades 17 and 18 can be simplified, and the manufacturing cost can be reduced and accidents such as water leakage from the blades 17 and 18 can be avoided. it can. Then, the slag discharged to the outside of the rotary hood 11 by the screw conveyor 15 is subjected to aging treatment and then effectively used as a roadbed material or a material for civil engineering landfill.

[0014]

EXAMPLES Next, examples of the cooling method of the molten slag granulating equipment according to the present invention will be described. Two rotary drums having a diameter of 780 mm and a length of 930 mm were arranged in the rotary hood, and 12 pieces of steel blades each having a height of 100 mm and having the same length as the length of the rotary drum were attached to the outer periphery of the rotary drum. . Then, 10 to 20 tons of molten slag generated by decarburization and refining in a refining furnace such as a converter or an electric furnace is put in a slag pan, and the slag pan is conveyed to be passed through a trough to be 141
The molten slag of 0 to 1540 ° C. is flown down to the first rotary drum, and the shearing of the molten slag is performed by the rotation of the two rotary drums and the surrounding blades, and at the same time water is sprayed from the spray spray holes of the spray pipe. The molten slag was rapidly cooled. Further, spray water is sprayed from each of 10 spray nozzles provided in a water supply pipe for spraying, which is arranged below the rotary drums and directed toward the blades, to cool the surface of the blades and the water to the surface of the blades. A film was formed. Further, the rotary drum was operated at a rotation speed of 300 to 410 rpm. Examples 1 to 5 are two rotary drums equipped with blades having a solid structure having no cooling water supply passage inside the blades.
The life index of the blade when the internal cooling of the conventional blade is set to 1 by treating the molten slag while cooling the surface of the blade by spraying from the spray nozzle with the cooling water amount of 20 to 500 liters / minute · m, respectively. investigated. The results are shown in Table 1. By setting the amount of water sprayed to the surface of the blade to 20 liters / min.m or more, the life index of the blade is 1.05.
In the range of 50 to 200 liters / minute · m, the spray water amount is most remarkable, the blade replacement frequency is extremely small, and the operating rate of the processing apparatus can be improved.

[0015]

[Table 1]

On the other hand, Comparative Examples 1 to 5 shown in Table 2
Conventional cooling of the inside of the blade and 20 to 500 liters / minute
This is a case where the cooling of the blade surface and the rotating drum by spraying m of spray water is used together. By using the internal cooling and the surface cooling of the blade together, the blade life can be further improved. Compared to the case of only surface cooling, the improvement margin was small. In addition to the above-mentioned conditions, cooling is performed only with spray water sprayed on the surface of the blade attached around the rotary drum, and the spray water amount at that time is set to 2
The molten slag was treated while cooling the surface of the blade at less than 0 liter / min · m, but the amount of spray water was insufficient and the blade was melted and the blade life was shortened.

[0017]

[Table 2]

The embodiment of the present invention has been described above.
The present invention is not limited to the above-described embodiment, and changes in conditions and the like without departing from the spirit are all within the scope of application of the present invention. For example, in addition to spraying water on the blades 17 and 18 of the rotating drums 19 and 20 using a spray nozzle, spraying water with a mixture of gas and water using a steam nozzle, or spraying water from these spray nozzles. A combination of steam sprays can be used.

[0019]

In the cooling method for the molten slag granulating equipment according to the first and second aspects of the present invention, the cooling water is sprayed from the high-speed rotating body and a plurality of spray nozzles arranged so as to direct the blades. Also, since the blades are cooled, it is possible to enhance the cooling of the blades provided on the high-speed rotating body to suppress wear, reduce the frequency of blade replacement, and improve the productivity of the slag granulating equipment.

Particularly, in the method for cooling the molten slag granulating equipment according to the second aspect, the amount of cooling water sprayed from the spray nozzle is 20 to 20 per unit length in the axial direction of the high-speed rotating body.
Since it is set to 500 liters / minute · m, it is possible to further enhance cooling of the blades and reliably prevent wear, reduce the frequency of blade replacements, and more stably improve the productivity of the slag granulating equipment.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of molten slag granulation equipment applied to a method for cooling molten slag granulation equipment according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line AA of FIG.

FIG. 3 is a schematic diagram showing a state in which cooling water is sprayed onto the blades of a rotating drum.

[Explanation of symbols]

10: Molten slag granulation equipment, 11: Rotary hood,
12: Molten slag, 13: Slag pan, 14: Gutter, 15: Screw conveyor, 16: Chimney, 17: Blade, 18: Blade, 19: Rotating drum, 19a: Shaft, 19b: Drive transmission wheel, 19c: Bearing , 19d: rotary joint,
20: rotating drum, 20a: shaft, 20b: drive transmission wheel,
20c: bearing, 20d: rotary joint, 2
1: Water spray hole, 22: Water spray hole, 23: Water pipe, 2
4: Sprinkling pipe, 25: Cooling water pipe, 25a: Cooling water supply pipe,
26: Water supply pipe, 27: Water supply pipe for spraying, 27a: Spray nozzle, 28: Water supply pipe for spraying, 28a: Spray nozzle

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Toshitaka Yuki             No. 1-1 Tobatacho, Tobata-ku, Kitakyushu City, Fukuoka Prefecture New             Nippon Steel Co., Ltd., Yawata Works (72) Takayuki Kaneyasu, inventor             No. 1-1 Tobatacho, Tobata-ku, Kitakyushu City, Fukuoka Prefecture New             Nippon Steel Co., Ltd., Yawata Works (72) Inventor Yukio Miki             1-36 Makiyama, Tobata-ku, Kitakyushu, Fukuoka Prefecture               Hamada Heavy Industries Co., Ltd. (72) Inventor Morio Tsuchiya             1-36 Makiyama, Tobata-ku, Kitakyushu, Fukuoka Prefecture               Hamada Heavy Industries Co., Ltd. (72) Inventor Shigeyuki Tomihara             1-36 Makiyama, Tobata-ku, Kitakyushu, Fukuoka Prefecture               Hamada Heavy Industries Co., Ltd. F-term (reference) 4G012 JK05                 4K012 AA02 AA05                 4K063 AA03 BA02 CA02 CA05 HA19

Claims (2)

[Claims] 1. A method for cooling a molten slag granulating facility, wherein molten slag discharged from a refining furnace is made to flow into a blade radially attached to a high-speed rotating body to granulate the molten slag. And a method for cooling molten slag granulation equipment, characterized in that cooling water is sprayed from a plurality of spray nozzles arranged with the blades oriented to cool the high-speed rotating body and the blades. 2. The method for cooling a molten slag granulating facility according to claim 1, wherein the amount of cooling water sprayed from the spray nozzle is 20 per unit length in the axial direction of the high-speed rotating body.
A method for cooling a granulation facility for molten slag, characterized in that it is set to 500 liters / minute · m.