JP7251498B2 - Granulated iron manufacturing equipment - Google Patents

Description

TECHNICAL FIELD The present invention relates to a granulated iron production apparatus for producing granulated iron from molten iron.

There is a process to produce iron granules from molten iron produced in a blast furnace or the like. Patent Literature 1 discloses a granular metal production method in which molten iron is dropped onto a fixed plate, and the droplets bounce off the fixed plate and drop into a cooling bath below to be cooled, thereby producing granular iron. ing. Further, Patent Document 2 discloses an apparatus for producing a large amount of granulated iron by granulating molten iron with a stream of water, dropping the liquid granulated iron into water, and cooling and solidifying the granulated iron.

The molten iron granules as they are cast are hot liquids. Since the temperature of molten iron is about 1200 to 1500°C, when such high-temperature molten iron comes into contact with water, a vapor film forms on the surface of the high-temperature object, creating a film boiling state in which the water evaporates and takes heat from the molten iron. . This film boiling has a low cooling capacity and, for example, a heat transfer coefficient that is only several hundredths of that of nucleate boiling in which no vapor film is formed. Therefore, when film boiling continues for a long time, the iron granules are not sufficiently cooled, and the iron granules fuse together in the cooling water. When the iron granules are fused together, the iron granules of sizes that are difficult to convey increase, making transportation difficult. In addition, if the cooling water is included when the iron granules are fused together, it may cause a steam explosion.

Also, when the temperature of the cooling water is high, the water is likely to boil, so that a vapor film is likely to be maintained around the high-temperature object, and film boiling is likely to occur. Therefore, when the temperature of the cooling water rises, the ability to cool the iron granules is significantly reduced, and fusion between the iron granules is likely to occur. In order to solve such a problem, Patent Document 3 discloses that the cooling water temperature in the pit is maintained at 68°C or less by adjusting the cooling water amount of the secondary cooling water, thereby preventing the fusion of iron particles deposited in the pit. It is disclosed that it can be suppressed.

Japanese Patent Publication No. 52-20948 Japanese Patent Application Publication No. 2018-512499 JP-A-9-20902

Considering that the iron granules spread horizontally to some extent when the iron granules are produced from molten iron and the installation space for the conveying device for the solidified iron granules, a cooling water tank of a considerable size is required to cool the iron granules. The cooling water tank is provided with a discharge port for supplying cooling water and a drain port for conveying the cooling water whose temperature has risen to the cooling equipment. It is difficult to control the flow of cold cooling water through a large water tank, and the cooling water flow can create stagnant areas within the water tank. If the warm cooling water used for cooling the iron granules stays in this stagnant region, there may be a region where the water temperature is locally high. If a large amount of iron granules is thrown into this region, the film boiling state is maintained for a long time, and cooling is not possible sufficiently. become difficult. There is a problem that if water is included in the fused material, it may cause a steam explosion.
The present invention has been made to solve the above-mentioned problems, and its object is to provide a granulated iron manufacturing apparatus capable of efficiently cooling granulated iron and suppressing fusion between the granulated iron. .

Means for solving the above problems are as follows.
(1) A granulating device for making droplets of molten iron, a water flow control container provided at a position to receive the droplets and containing cooling water, connected to the water flow control container, and supplying cooling water to the water flow control container. and at least one cooling water pipe for supplying cooling water, wherein the water flow control container has an inclined surface inclined downward so that the horizontal cross-sectional area of the water flow control container becomes narrower, and below the inclined surface is a granulated iron manufacturing device provided with an outlet.
(2) The iron granule manufacturing apparatus according to (1), wherein the angle of the inclined surface with respect to the horizontal plane is in the range of 40° or more and 60° or less.
(3) The apparatus for manufacturing iron granules according to (1) or (2), further comprising a cooling water tank containing cooling water, wherein the cooling water tank contains the water flow control container.
(4) The iron granule manufacturing apparatus according to (3), further comprising a conveying device below the water flow control vessel for conveying the cooled iron granules to the outside of the cooling water tank.

In the apparatus for manufacturing iron granules of the present invention, cooling water is supplied into the water flow control container having an inclined surface to form a swirling flow of the cooling water, whereby the iron granules can be efficiently cooled. The countercurrent flow can cool the iron granules more efficiently. As a result, it is possible to prevent the iron granules from being sufficiently cooled and fused together. By preventing the fusion between the iron granules, it is possible to prevent the occurrence of a steam explosion caused by the inclusion of water in these fused substances.

1 is a schematic diagram showing an example of an iron granule manufacturing apparatus 10 according to this embodiment. FIG. 2 is a schematic diagram of a water flow control container 20; FIG. 4 is a schematic cross-sectional view showing another example of the water flow control container 20. FIG.

Hereinafter, the present invention will be described through embodiments of the invention. FIG. 1 is a schematic diagram showing an example of an iron granule manufacturing apparatus 10 according to this embodiment. The granulated iron production apparatus 10 is an apparatus for producing granulated iron from molten iron. The molten iron may be molten iron produced in a blast furnace, molten steel, or produced by melting scrap in an electric furnace. Molten iron used in the granulated iron production apparatus 10 can be produced by any production method as long as it contains iron as a main component.

The granulated iron manufacturing apparatus 10 according to the present embodiment includes a granulating device 12 that makes droplets of molten iron, a water flow control container 20 that contains cooling water, and a cooling water pipe 30 that supplies cooling water 40 to the water flow control container 20. , a cooling water tank 32 and a conveying device 34 . Molten iron is transported to a location where the granulated iron manufacturing apparatus 10 is installed by a hot metal ladle, torpedo car, or the like. The transported molten iron is made into droplets by the granulator 12 . The granulating device 12 has, for example, a tundish 14 and a refractory 16, and makes the molten iron 18 contained in the tundish 14 flow out and collide with the refractory 16 to form droplets. is. Note that the granulating device 12 is not limited to this, and may be a device that causes water to collide with the molten iron 18 that has flowed out from the tundish 14 to form droplets. By using these granulating devices 12, the molten iron can be adjusted into droplets that become granulated iron with a predetermined particle size.

As the shape of the droplet increases, the heat capacity increases and it takes time to solidify. Partially melted iron granules come into contact with each other and fuse together in the water flow control container 20, forming a large lump that can be taken out and transported. It may become difficult. For this reason, the granulating device 12 preferably forms liquid droplets so that the maximum length of granulated iron after cooling is 50 mm or less. The molten iron 18 is made into droplets by the granulator 12 and falls into the water flow control vessel 20 .

The water flow control container 20 is a cylindrical container and has an inclined surface 22 inclined downward so that the horizontal cross-sectional area of the water flow control container 20 becomes narrower. The hole at the lower end of the water flow control vessel 20 with the ramp 22 is an outlet 26 for cooled and solidified iron granules. A discharge port 24 to which a cooling water pipe 30 is connected is provided on the inclined surface of the water flow control container 20 .

The cooling water pipe 30 is a water pipe through which the cooling water 40 cooled to 0° C. or more and 35° C. or less by a cooling device (not shown) passes. The cooling water 40 passes through the cooling water pipe 30 and is discharged into the water flow control container 20 from the discharge port 24 . In the example shown in FIG. 1, an example in which one cooling water pipe 30 is connected to the water flow control container 20 is shown. That is, the iron granule manufacturing apparatus 10 should have at least one or more cooling water pipes connected to the water flow control container 20 .

A water flow control vessel 20 is provided at a position to receive the molten iron 18 dropletized by the granulator 12 . The liquid droplets of molten iron 18 are introduced into the water flow control container 20 from the upper end of the water flow control container 20 . The liquid droplets of the molten iron 18 are cooled by the cooling water 40 in the water flow control container 20 to form iron granules. Granulated iron descends on the inclined surface 22 due to gravity and is discharged from the discharge port 26 . Granulated iron is thus produced from the molten iron 18 .

The inclined surface 22 guides the produced granulated iron to the discharge port 26 . For this reason, the inclination angle of the inclined surface 22 with respect to the horizontal plane is preferably equal to or greater than the angle of repose of iron granules. That is, it is preferable that the angle of the inclined surface 22 with respect to the horizontal plane is within the range of 40° or more and 60° or less. By setting the inclination angle of the inclined surface 22 with respect to the horizontal plane to 40° or more, the iron granules can be guided to the discharge port 26 without remaining on the inclined surface 22 . Furthermore, by setting the inclination angle to 60° or less, the inclined surface for guiding to the conveying device 34 can be shortened, and it is possible to suppress the increase in the size of the granulated iron manufacturing apparatus 10 due to the depth of the water flow control container 20 becoming deep. .

Cooling water tank 32 accommodates cooling water 40 , water flow control container 20 and carrier device 34 . The water flow control container 20 is installed in cooling water 40 contained in the cooling water tank 32 . The cooling water 40 contained in the cooling water tank 32 is the cooling water 40 drained from the water flow control container 20 . As for the cooling water contained in the cooling water tank 32, the same amount of cooling water 40 as the cooling water discharged from the cooling water pipe 30 is discharged from the drain port 33 so that the cooling water surface of the cooling water tank 32 is constant. By using the large-capacity cooling water tank 32, the cooling water surface can be easily controlled, and the iron granules can be produced stably.

The conveying device 34 conveys the iron granules discharged from the discharge port 26 to a predetermined position outside the cooling water tank 32 . The conveying device 34 is a device for conveying the cooled granulated iron out of the cooling water tank 32 . Any device capable of transporting iron granules can be used as the transport device 34 without limiting the transport method or device configuration. However, it is preferable to use a mesh conveyor as the conveying device 34 so that the cooling water 40 is not carried out of the cooling water tank 32 .

FIG. 2 is a schematic diagram of the water flow control container 20. As shown in FIG. 2(a) is a schematic side cross-sectional view of the water flow control container 20, and FIG. 2(b) is a schematic top view of the water flow control container 20. FIG. As shown in FIG. 2( a ), the cooling water 40 discharged from the discharge port 24 collides with the inclined surface 22 to change the flow direction of the cooling water 40 . Due to this change in flow direction, an upward swirling flow 42 is generated in the water flow control container 20 while rotating in the horizontal direction (clockwise when viewed from above in FIG. 2(b)). The swirling flow 42 suppresses the formation of a stagnation region in the water flow control vessel 20, so that local temperature rise of the cooling water 40 is suppressed, and the iron granules can be efficiently cooled. fused together without being Also from the viewpoint of generating the swirling flow 42, the angle of the inclined surface 22 with respect to the horizontal plane is preferably 40° or more and 60° or less. If the amount of the cooling water 40 discharged from the cooling water pipe 30 is less than the amount of water discharged from the discharge port 26, the cooling water 40 will be discharged from the discharge port 26. Swirling flow is no longer generated. Therefore, the amount of cooling water 40 discharged from the cooling water pipe 30 is set to be at least greater than the amount of water discharged from the outlet 26 .

Moreover, it is preferable that the discharge port 24 is provided below the central position in the vertical direction of the water flow control container 20 so that the cooling water 40 is discharged from below the water flow control container 20 . When the cooling water 40 is discharged into the water flow control container 20, the cooling water 40 is directed upwards to the wide opening. Therefore, when the cooling water 40 is discharged from below, it flows from below to above inside the water flow control container 20 . On the other hand, since the iron granules descend from above the water flow control vessel 20 downward, the iron granules and the cooling water 40 flow countercurrently, and the cooling efficiency of the iron granules by the cooling water 40 increases. As a result, the cooling of the iron granules by the cooling water 40 is further promoted, and the fusion of the iron granules to each other due to insufficient cooling is further suppressed.

On the other hand, if the cooling water temperature is too low, the steam film on the surface of the iron granules becomes unstable, and spontaneous nucleation of water occurs on the surface of the iron granules, which may cause a steam explosion. In response to this, the discharge port 24 is provided below the water flow control container 20, and the cooling efficiency is increased by counterflowing the iron granules and the cooling water 40, so that the water temperature of the cooling water 40 above the water flow control container 20 is high. Therefore, it is possible to suppress the occurrence of a steam explosion due to a decrease in cooling water temperature.

Furthermore, when the water flow control container 20 has a cylindrical shape, the flow direction of the cooling water discharged from the discharge port 24 is the eccentric direction (center direction) of the water flow control container 20 as shown in the top view of FIG. direction passing through the eccentricity different from the direction). By discharging the cooling water in such a direction, the horizontal swirling flow 42 is easily formed when the cooling water 40 collides with the opposing inclined surface 22 . On the other hand, when the cooling water 40 is discharged in the direction passing through the center of the water flow control container 20, the flow direction of the cooling water 40 is difficult to change horizontally when it collides with the opposing inclined surface 22, and a swirling flow 42 is formed. becomes difficult. Further, if the cooling water 40 is discharged in a direction passing through the center of the water flow control container 20, the impetus of the cooling water flow decreases due to collision with the inclined surface 22, which is not preferable.

In this embodiment, the iron granule manufacturing apparatus 10 includes a granulating device 12, a water flow control container 20 containing cooling water 40, a cooling water pipe 30 supplying the cooling water 40 to the water flow control container 20, a cooling water tank 32, Although an example having the transport device 34 has been shown, the present invention is not limited to this. The iron granule manufacturing apparatus may not have the cooling water tank 32 and the conveying device 34 . Also, the cooling water pipe 30 does not necessarily have to be provided on the inclined surface of the water flow control container 20 . If the cooling water tank 32 is not provided, the cooling water 40 is drained from above and below the water flow control container 20 . Granulated iron and wastewater are separated using a mesh-like member below the water flow control container 20, and the separated wastewater is recovered from the molten iron 18 in the same manner as in the granular iron manufacturing apparatus 10 shown in FIG. Can produce iron granules. Furthermore, although FIGS. 1 and 2 show an example in which the water flow control container 20 has a cylindrical shape, it is not limited to this. The water flow control container 20 does not have to be cylindrical as long as it has a cylindrical shape and has an inclined surface 22 .

FIG. 3 is a schematic cross-sectional view showing another example of the water flow control container 20. As shown in FIG. FIGS. 3(a) to 3(c) show examples in which a cooling water pipe 50, 52 or 54 is provided above the water flow control vessel 20. FIG. As shown in FIGS. 3(a) to 3(c), the cooling water pipe 50, 52 or 54 is provided above the water flow control container 20, and the cooling water 40 is discharged downward from the cooling water pipe. By colliding with the surface 22, the flow direction of the cooling water 40 is changed to generate a swirling flow that rotates in the vertical direction. This swirling flow suppresses a local temperature rise of the cooling water in the water flow control container 20, and prevents the iron granules from being sufficiently cooled and fused to each other. Even in the case shown in FIG. 3B, if the amount of cooling water discharged from the cooling water pipe 52 is larger than the amount of cooling water discharged from the discharge port 26, the cooling water that is not discharged from the discharge port 26 40 collides with the inclined surface 22 to generate a swirling flow.

3(d) to (f) show an example in which the cooling water pipe 30, 56 or 58 is connected to the inclined surface of the water flow control container 20. FIG. In FIG. 3(d), the cooling water pipe 30 is positioned higher than the water flow control container 20 shown in FIGS. When the cooling water pipes 30, 56, or 58 are connected to the inclined surface of the water flow control container 20, a swirling flow is generated that rotates upward while rotating in the horizontal direction as described with reference to FIG. A local temperature rise of the cooling water 40 is suppressed, and the iron particles are prevented from being sufficiently cooled and fused to each other. Furthermore, since a swirling flow is formed that flows upward from the bottom of the water flow control vessel 20, the iron granules and the cooling water 40 flow countercurrently, improving the cooling efficiency of the cooling water 40 and reducing the temperature of the cooling water to prevent steam explosion. Suppression is realized.

3(g) and (h) show an example in which a cooling water pipe 60 or 62 is provided below the water flow control container 20. FIG. As shown in FIGS. 3(g) and 3(h), when the cooling water 40 is discharged upward from the cooling water pipes 60 and 62, the iron granules and the cooling water 40 flow countercurrently. Improvement of cooling efficiency and suppression of steam explosion due to cooling water temperature drop are realized.

As described above, in the iron granule manufacturing apparatus according to the present embodiment, the water flow control container 20 which contains the cooling water 40 and has an inclined surface inclined downward so that the horizontal cross-sectional area of the water flow control container 20 becomes narrower. By discharging the cooling water 40 from the cooling water pipe to the water flow control container 20, a swirling flow of the cooling water 40 is formed, and the iron granules can be efficiently cooled. By forming the flow, the iron granules can be cooled more efficiently, and the iron granules can be prevented from being fused together due to insufficient cooling. This makes it easier to take out and transport the iron granules, and also prevents water from being included in the melted material and causing a steam explosion.

REFERENCE SIGNS LIST 10 granulated iron manufacturing device 12 granulating device 14 tundish 16 refractory 18 molten iron 20 water flow control container 22 inclined surface 24 discharge port 26 discharge port 30 cooling water pipe 32 cooling water tank 33 drain port 34 conveying device 40 cooling water 42 swirling flow 50 cooling Water pipe 52 Cooling water pipe 54 Cooling water pipe 56 Cooling water pipe 58 Cooling water pipe 60 Cooling water pipe 62 Cooling water pipe

Claims (4)

a granulating device that makes molten iron into droplets;
a water flow control container provided at a position for receiving the droplets and containing cooling water;
at least one cooling water pipe connected to the water flow control vessel and supplying cooling water to the water flow control vessel;
has
The water flow control container has an inclined surface inclined downward so that the horizontal cross-sectional area of the water flow control container becomes narrower, and a discharge port is provided below the inclined surface,
The cooling water pipe is connected downward from a vertical center position of the water flow control container in a direction passing through an eccentricity different from the center of the water flow control container. 2. The iron granule manufacturing apparatus according to claim 1, wherein the angle of said inclined surface with respect to a horizontal plane is within a range of 40[deg.] or more and 60[deg.] or less. further comprising a cooling water tank containing cooling water;
3. The iron granule manufacturing apparatus according to claim 1, wherein said cooling water tank accommodates said water flow control container. 4. The iron granule manufacturing apparatus according to claim 3, further comprising a conveying device for conveying the cooled iron granules to the outside of the cooling water tank below the water flow control vessel.

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