Granular iron manufacturing apparatus

Abstract

A pellet manufacturing apparatus is provided that can efficiently cool molten iron and efficiently cool pellets during transport in conveying devices such as conveyors, thereby inhibiting the agglomeration of pellets. The pellet manufacturing apparatus includes: a pelletizing device for forming molten iron into droplets; a cooling water tank for cooling the droplets by dropping them into cooling water to form pellets; and a conveying device for conveying the pellets outside the aforementioned cooling water tank. The pellet manufacturing apparatus also includes: a water flow control container provided within the cooling water tank and open at both ends; and a cooling water pipe assembly for supplying cooling water to the water flow control container. The conveying device includes: a conveyor provided below the water flow control container and conveying the pellets from inside the cooling water tank to outside the cooling water tank; and a cooling water supply device provided above the conveyor within the cooling water tank and supplying cooling water to cool the pellets conveyed by the conveyor.

Description

Technical Field

[0001] This invention relates to an apparatus for producing granulated iron from molten iron. Background Technology

[0002] Ferrous iron is obtained by dispersing molten iron or molten steel and then solidifying it into granules, with an average particle size of several millimeters to tens of millimeters. In integrated steel plants, in cases of malfunctions or other issues in subsequent steelmaking processes, resulting in a sudden surplus of molten iron produced in the blast furnace, this surplus is temporarily stored as ferrous iron. In recent years, blast furnaces have become increasingly larger, and the inability to temporarily handle large quantities of molten iron would lead to reduced blast furnace production. Therefore, buffer equipment is needed to handle situations such as malfunctions in subsequent steelmaking processes.

[0003] Due to the need to reduce CO2 emissions in the iron and steel industry in recent years, the demand for reduced iron produced using hydrocarbon gases such as hydrogen or natural gas instead of coke (carbon source) as a reducing agent has increased. To manufacture steel products from reduced iron with high p-content gangue (mainly SiO2 and Al2O3), gangue removal and dephosphorization are essential after the reduction iron is produced. Therefore, as a pretreatment for steel product manufacturing, reduced iron is sometimes temporarily melted to form molten iron, which is then subjected to gangue removal and dephosphorization treatments, allowing the treated molten iron to be stored as transportable granular iron.

[0004] As a method for granulating molten iron, Patent Document 1 discloses a method of granulation by blowing pressurized water onto molten iron. However, in the method disclosed in Patent Document 1, the granulated iron often becomes hollow, and water accumulates in the hollow part, posing a risk of steam explosion during remelting. Patent Document 2 discloses a method for manufacturing granulated metal, in which molten iron is dropped onto a fixed plate, the droplets bounce off the fixed plate, and fall into a cooling bath below to be cooled, thereby producing granulated iron. The granulated iron cooled in the cooling water tank is collected through a cylindrical flat plate structure and pipes that gradually taper to the lower half of the cylinder, and piled on a conveyor that serves as a transport device. The conveyor transports the granulated iron from the cooling water tank to a drying device and a storage device. Patent Document 3 discloses an apparatus that uses water flow to granulate molten iron, by dropping liquid granulated iron into the water, thereby cooling and solidifying it to produce a large quantity of granulated iron.

[0005] When iron granules are added to water, they are at a high temperature, approximately 1200–1500°C. Therefore, when such hot iron granules come into contact with water, they enter a state of film boiling, where a vapor film forms on the surface of the hot object. As a result, the water evaporates, gradually taking away the heat from the iron granules. The cooling capacity of film boiling is relatively low; for example, it has only a heat transfer coefficient of about one-hundredth that of nucleus boiling, which does not produce a vapor film. Therefore, if film boiling continues for a long time, the iron granules may not be sufficiently cooled, and they may fuse and agglomerate together in the cooling water.

[0006] If the cooling water temperature is high, the water boils easily, thus easily maintaining a vapor film around a high-temperature object, which can easily lead to film boiling. Therefore, if the cooling water temperature increases, the cooling capacity of the iron particles decreases significantly, making it easier for the iron particles to agglomerate. To address this problem, Patent Document 3 suggests adjusting the cooling water volume of the secondary cooling water to maintain the cooling water temperature in the pit below 68°C, thereby suppressing the agglomeration of iron particles accumulated in the pit.

[0007] Existing technical documents Patent documents Patent Document 1: Japanese Patent Application Publication No. 2018-115363 Patent Document 2: Japanese Patent Publication No. 52-20948 Patent Document 3: Japanese Patent Application Publication No. 9-20902 Summary of the Invention

[0008] The problem that the invention aims to solve If we consider the horizontal expansion of molten iron droplets during the production of granulated iron from molten iron, and the space required for the conveying device of the solidified granulated iron, then cooling the granulated iron requires a fairly large cooling water tank. The cooling water tank is equipped with spray outlets for supplying cooling water and drain outlets for conveying the heated cooling water to the cooling equipment, thereby circulating the cooling water within the cooling water tank and the cooling equipment.

[0009] However, it is difficult to control the distribution of low-temperature cooling water throughout the entire wide cooling water tank. Patent Document 3 describes adjusting the cooling water volume of the secondary cooling water to maintain the cooling water temperature in the pit below 68°C, but it does not describe any method for controlling the water flow in the cooling water tank. Depending on the flow of the cooling water, stagnant areas may sometimes form in the cooling water tank. If the cooling water, which is used to cool the granulated iron, becomes warmed and stagnant in these stagnant areas, localized areas of high water temperature may appear. If a large amount of granulated iron is added to these high-temperature areas, the film boiling state will be maintained for a long time, the granulated iron cannot be cooled sufficiently, and the granulated iron will fuse and agglomerate together. If the granulated iron agglomerates together, the number of granulated iron particles of different sizes that are difficult to transport increases, making transport difficult. There is a problem that if cooling water is contained within the agglomerated granulated iron, it could become a cause of steam explosion.

[0010] In Patent Document 2, even if the surface of the granular iron has cooled and solidified before it is collected onto the conveyor, the interior of the granular iron remains in a high-temperature, unsolidified state. Furthermore, because the granular iron is densely packed on the conveyor, when the heat removed from the surface by the cooling water decreases, the heat transfer from the interior of the granular iron to the surface exceeds the heat removed by the cooling water, resulting in a reheating phenomenon where the surface temperature of the granular iron rises again. Therefore, the following problem exists: during the conveying process, reheating occurs, the surface temperature of the granular iron rises again, and the accumulated granular iron easily fuses and agglomerates into large lumps.

[0011] The present invention was made to solve the above-mentioned problems, and its object is to provide a pellet manufacturing apparatus that can efficiently cool molten iron and efficiently cool pellets during transport in conveying devices such as conveyors, thereby inhibiting the agglomeration of pellets.

[0012] Methods for solving problems The means to solve the above problems are as follows.

[0013] [1] A pellet iron manufacturing apparatus comprising: a pelletizing device for forming molten iron into droplets; a cooling water tank for cooling the droplets in cooling water to form pellet iron; and a conveying device for conveying the pellet iron to the outside of the cooling water tank. The pellet iron manufacturing apparatus further comprises: a water flow control container disposed in the cooling water tank and open at both ends; and a cooling water pipe assembly for supplying cooling water to the water flow control container. The water flow control container comprises: a partition cylinder having an inclined surface that narrows the horizontal cross-sectional area downwards; and a pipe cylinder connected to the lower part of the partition cylinder. The cooling water pipe assembly comprises: an upper cooling water pipe assembly and a middle cooling water pipe assembly connected to the partition cylinder; and a lower cooling water pipe assembly connected to the pipe cylinder. The upper cooling water pipe assembly is connected to an upper section including the inclined surface at the upper end of the partition cylinder. Using the cooling water supplied from the upper cooling water pipe assembly, a cooling water flow is generated from top to bottom along the inclined surface. The cooling water flow is as follows: the aforementioned middle section cooling water pipe assembly is horizontally connected to the core of the aforementioned partition cylinder and the middle section of the inclined surface of the aforementioned partition cylinder. A first circulating flow is generated by the cooling water supplied from the aforementioned middle section cooling water pipe assembly. The aforementioned first circulating flow is directed toward the core of the aforementioned partition cylinder, converges and rises at the core of the aforementioned partition cylinder, and circulates within the aforementioned partition cylinder along the inclined surface from top to bottom. The aforementioned lower section cooling water pipe assembly is connected to the side of the aforementioned pipe cylinder. A second circulating flow is generated within the aforementioned pipe cylinder by the cooling water supplied from the aforementioned lower section cooling water pipe assembly and the drainage from the aforementioned partition cylinder. The aforementioned conveying device includes: a conveyor disposed below the aforementioned water flow control container and conveying the aforementioned granular iron from inside the aforementioned cooling water tank to outside the aforementioned cooling water tank; and a cooling water supply device disposed above the aforementioned conveyor within the aforementioned cooling water tank and supplying cooling water for cooling the aforementioned granular iron transported by the aforementioned conveyor.

[0014] [2] The granulated iron manufacturing apparatus as described in [1] has a control device for controlling the amount of cooling water supplied from the aforementioned cooling water pipe group to the aforementioned water flow control container, the aforementioned control device controlling the amount of cooling water supplied from the aforementioned cooling water pipe group to decrease in the order of the aforementioned middle section cooling water pipe group, the aforementioned upper section cooling water pipe group, and the aforementioned lower section cooling water pipe group.

[0015] [3] The granulated iron manufacturing apparatus as described in [1] or [2], wherein the cooling water supply device comprises: a cooling water main pipe that supplies the cooling water to the upper region of the granulated iron on the conveyor and is provided along the conveying direction of the conveyor; and a plurality of cooling water manifolds arranged in the conveying direction and respectively connected to the cooling water main pipe, and the cooling water manifolds extending along the width direction of the conveyor and having at least one supply port in the width direction.

[0016] [4] The granulated iron manufacturing apparatus as described in [1] has a protrusion that covers the upper side of the connection between the upper section cooling water pipe assembly and / or the middle section cooling water pipe assembly and the inclined surface.

[0017] [5] The granulated iron manufacturing apparatus as described in [4], wherein the cross-sectional shape of the aforementioned protrusion is an inverted V-shape or an inverted U-shape that extends from top to bottom.

[0018] [6] The granulated iron manufacturing apparatus as described in any one of [1], [4] and [5], wherein a protective cover is provided, the protective cover covering the upper side of the connection between the upper section cooling water pipe assembly and the inclined surface, and the upper end of the protective cover is closed.

[0019] [7] The granulated iron manufacturing apparatus as described in [6], wherein the cross-sectional shape of the aforementioned protective cover is a semi-circular or semi-elliptical shape that extends from top to bottom.

[0020] [8] The granulated iron manufacturing apparatus as described in [3], wherein the aforementioned supply port is a rectangular slit with a short side length of 3 mm or more.

[0021] Invention Effects In the granulated iron manufacturing apparatus of the present invention, a first circulating flow of cooling water from bottom to top is generated in the partition cylinder, and a second circulating flow of cooling water from bottom to top is generated in the pipe cylinder, and the granulated iron is cooled by these circulating flows. This improves the cooling efficiency of the granulated iron in the partition cylinder and pipe cylinder, and prevents the granulated iron from fusing and agglomerating during cooling. Furthermore, in the granulated iron manufacturing apparatus of the present invention, cooling water is supplied above the granulated iron being transported in the conveying device where granulated iron tends to accumulate and become dense, thus cooling the granulated iron. Therefore, by replacing the cooling water in a limited area of ​​the conveying device that collects the granulated iron, the granulated iron can be cooled efficiently, and the fusing and agglomeration of the granulated iron during transport by the conveying device can be prevented.

[0022] In this way, the granulated iron manufacturing apparatus of the present invention can improve the cooling efficiency of granulated iron to manufacture granulated iron, thereby reducing the amount of cooling water used. Furthermore, since the cooling efficiency of granulated iron is high, if the granulated iron cooling capacity of the manufacturing apparatus is made the same, it can become a more compact device, thereby suppressing the enlargement of equipment; if the size of the manufacturing apparatus is made the same, it can become a device capable of manufacturing more granulated iron. Attached Figure Description

[0023] [ Figure 1 ] Figure 1 This is a cross-sectional schematic diagram of the granulated iron manufacturing apparatus according to this embodiment.

[0024] [ Figure 2 ] Figure 2This is a cross-sectional schematic diagram of the water flow control container connected to the cooling water pipe assembly.

[0025] [ Figure 3 ] Figure 3 This is a cross-sectional schematic diagram illustrating the circulating flow generated within the separating cylinder and the pipe cylinder.

[0026] [ Figure 4 ] Figure 4 This is a schematic diagram showing a portion of the conveying device.

[0027] [ Figure 5 ] Figure 5 This is a cross-sectional schematic diagram showing other water flow control containers used in the granulated iron manufacturing apparatus according to this embodiment.

[0028] [ Figure 6 ] Figure 6 This is a schematic diagram of a water inlet with a protrusion, viewed from a horizontal perspective.

[0029] [ Figure 7 ] Figure 7 This is a cross-sectional schematic diagram showing other water flow control containers used in the granulated iron manufacturing apparatus according to this embodiment.

[0030] [ Figure 8 ] Figure 8 This is a schematic diagram of a water inlet with a protective cover, viewed from a horizontal perspective.

[0031] [ Figure 9 ] Figure 9 This is a diagram illustrating the simulation conditions of Invention Example 1 and Invention Example 2.

[0032] [ Figure 10 ] Figure 10 This is a diagram showing the simulation conditions for Comparative Example 1 and Comparative Example 2.

[0033] [ Figure 11 ] Figure 11 This is a diagram showing the simulation results of Invention Example 1 and Invention Example 2.

[0034] [ Figure 12 ] Figure 12 This is a three-dimensional schematic diagram showing the flow of cooling water supplied from each cooling water pipe assembly in Example 1 of the invention.

[0035] [ Figure 13 ] Figure 13 This is a graph showing the simulation results of Comparative Example 1 and Comparative Example 2.

[0036] [ Figure 14 ] Figure 14 This is a diagram showing the results of confirming whether granular iron has entered the water supply.

[0037] [ Figure 15 ] Figure 15 This is a schematic diagram of a pellet manufacturing apparatus used for simulation.

[0038] [ Figure 16 ] Figure 16 This is a diagram showing the results of simulating the water temperature in the space when cooling water is supplied from the cooling water supply device to the space.

[0039] [ Figure 17 ] Figure 17 This is a graph showing the results of simulating the temperature of granular iron on a conveyor. Detailed Implementation

[0040] The present invention will now be described through embodiments thereof. The following embodiments illustrate a preferred example of the invention, but the invention is not limited to these embodiments in any way.

[0041] Figure 1 This is a cross-sectional schematic diagram of the granulated iron manufacturing apparatus 70 according to this embodiment. The granulated iron manufacturing apparatus 70 is an apparatus that cools and solidifies molten iron, such as molten iron or molten steel, in a droplet state to produce granular iron material, i.e., granulated iron. The granulated iron manufacturing apparatus 70 includes a granulation device 10 for forming molten iron into droplets, a cooling water tank 20, a water flow control container 30, a cooling water pipe assembly 40, and a conveying device 50. The granulation device 10 includes an intermediate ladle 12 (such as a molten iron tank) that contains molten iron 60 and has a nozzle 16 at its bottom for ejecting molten iron, and a molten iron receiving plate 14 for the molten iron column 62 flowing down from the nozzle 16 to collide with it. The molten iron receiving plate 14 is made of a disc-shaped refractory material and is supported by a support body 18. When the molten iron column 62 flowing down from the nozzle 16 collides with the molten iron receiving plate 14, droplets 64 of the molten iron 60 scatter around it.

[0042] If the droplets 64 of molten iron 60 become larger, their heat capacity may increase, requiring more time for solidification. At high temperatures, the molten iron 60 may fuse and agglomerate within the water flow control container 30, forming large lumps that are difficult to transport by the conveying device 50. Therefore, it is preferable that the granulation device 10 forms the molten iron 60 into droplets 64 with a maximum length of 50 mm or less after cooling. The molten iron 60 is formed into droplets 64 by the granulation device 10 and falls onto the cooling water 24. Furthermore, the flow rate of molten iron 60 from the tundish 12 is controlled in the granulation device 10 such that the droplets 64 fall into the area where the water flow control container 30 is located.

[0043] The cooling water tank 20 contains cooling water 24 and a water flow control container 30. The water flow control container 30 is disposed within the cooling water 24 contained in the cooling water tank 20. The cooling water 24 contained in the cooling water tank 20 may include cooling water 24 discharged from the water flow control container 30. Regarding the cooling water 24 contained in the cooling water tank 20, an amount of cooling water 24 equal to the supplied cooling water is discharged from the drain outlet 22 in a manner that keeps the cooling water level in the cooling water tank 20 constant. By using a large-capacity cooling water tank 20, the cooling water level is easily controlled, and the production of granulated iron by the granulated iron manufacturing apparatus 70 is stable.

[0044] The water flow control container 30 is disposed within the cooling water tank 20 and is located at the position where the molten iron 60, which is formed into droplets 64 by the granulation device 10, is received. The water flow control container 30 uses the cooling water 24 contained inside to cool and solidify the droplets 64, thereby forming granulated iron 66.

[0045] The water flow control container 30 includes: a partition cylinder 32 having an inclined surface 34 that narrows downwards in a horizontal cross-sectional area; and a pipe cylinder 35 connected to the lower part of the partition cylinder 32. An inlet 33 for receiving droplets 64 is provided at the upper end of the partition cylinder 32, and an outlet 36 for discharging granular iron 66 is provided at the lower end of the pipe cylinder 35. That is, the water flow control container 30 is open at both the upper and lower ends. The inclined surface 34 can be formed on the inner side of the water flow control container 30; the shape of the outer side of the water flow control container 30 is not particularly limited. From the viewpoint of preventing granular iron 66 from accumulating, the inclination angle of the inclined surface 34 relative to the horizontal plane is preferably set to an angle in the range of 40 to 60°. Figure 1 The example shown illustrates an example where the upper end of the partition cylinder 32 does not have a cylindrical portion, but a cylindrical portion may also be provided on the upper end of the partition cylinder 32.

[0046] In this embodiment, the cooling area of ​​the granular iron 66 formed by the water flow control container 30 is designated as cooling area A. By setting the cooling area A formed by the water flow control container 30 in this way, the following effects (1) and (2) can be obtained.

[0047] (1) By centrally introducing cooling water 24 into cooling zone A, the granular iron 66 can be cooled efficiently.

[0048] (2) The granular iron 66 generated in the partition cylinder 32 can be collected at point 1 using the inclined surface 34, thus making the recycling of granular iron 66 easy.

[0049] The cooling water pipe assembly 40 is a water pipe assembly for supplying cooling water 24 cooled to between 0°C and 35°C by cooling equipment such as heat exchangers and cooling towers (not shown). When cooling water 24 is supplied from the cooling water pipe assembly 40 into the partition cylinder 32 of the water flow control container 30, the cooling water 24 flows upwards towards the larger opening. Therefore, if cooling water is supplied from below the partition cylinder 32 towards the core, the cooling water converges and rises within the core of the partition cylinder 32. On the other hand, if cooling water 24 is supplied from above the partition cylinder 32 downwards along the inclined surface 34, the cooling water 24 that converges and rises within the core of the partition cylinder 32 does not flow out from the inlet 33 of the partition cylinder 32 into the cooling water tank 20, but instead expands circumferentially near the inlet 33. This circumferentially expanding cooling water 24 generates a first circulating flow accompanying the cooling water flow descending from the inclined surface 34 of the partition cylinder 32. By generating this first circulating flow, the granular iron 66 can be cooled using countercurrent flow, and the stagnant area within the partition cylinder 32 can be reduced. The cooling water pipe assembly 40 has an upper cooling water pipe assembly 44 and a middle cooling water pipe assembly 46 connected to the partition cylinder, and a lower cooling water pipe assembly 48 connected to the pipe cylinder 35.

[0050] The intermediate cooling water pipe assembly 46 is horizontally connected to the core of the partition cylinder 32 in the middle section of an inclined surface 34 extending 650 mm below the center of the partition cylinder 32 in the vertical direction. When cooling water 24 is supplied into the partition cylinder 32 from the intermediate cooling water pipe assembly 46, the cooling water 24 flows towards the core of the partition cylinder 32, where it converges and rises. The rising cooling water 24 expands circumferentially at the upper end of the partition cylinder 32 and flows downwards along the inclined surface 34, forming a first circulation flow. The cooling water 24 supplied from the intermediate cooling water pipe assembly 46 forms a part of this first circulation flow.

[0051] The preferred cooling water volume supplied from the middle section cooling water pipe assembly 46 is 1500m³. 3 / h or above 3900m 3 / h or less. If the cooling water volume is less than 1500m³ 3 If the cooling water volume is less than 3900 m³ / h, a strong and stable upward flow is unlikely to be generated in the core of the separator 32, therefore it is not preferred. 3 If the flow rate is / h, then cooling water 24 will be generated that deviates from the first circulation flow and flows out from the inlet 33 of the partition cylinder 32 into the cooling water tank 20, which is therefore not preferred.

[0052] The flow velocity of the cooling water 24 supplied from the intermediate cooling water pipe assembly 46 is preferably between 1.8 m / s and 2.2 m / s. If the flow velocity of the cooling water 24 supplied from the intermediate cooling water pipe assembly 46 is slower than 1.8 m / s, the cooling water 24 will decelerate before reaching the core of the partition cylinder 32, making it difficult to generate a strong and stable upward flow, and therefore is not preferred. If the flow velocity of the cooling water 24 supplied from the intermediate cooling water pipe assembly 46 is faster than 2.2 m / s, the pressure loss in the cooling water pipe 41 will be high, requiring large-scale water delivery equipment such as pumps, and therefore is not preferred.

[0053] The upper section of the cooling water pipe assembly 44 is connected to the upper section of the inclined surface 34 at the upper end of the partition cylinder 32. The upper section of the cooling water pipe assembly 44 is connected to a water supply jacket 45, which covers the upper portion of the partition cylinder 32 and supplies cooling water to the slit 42 and the water supply port 43. The upper section of the partition cylinder 32 includes a slit 42 with a defined gap at the periphery of the upper end of the partition cylinder 32, and a water supply port 43 in the inclined surface 34 of the upper section of the partition cylinder 32. The upper section of the cooling water pipe assembly 44 is connected to the inclined surface 34 at the upper end of the partition cylinder 32, which covers a range from the upper end of the partition cylinder 32 to 1000 mm below it.

[0054] The flow velocity of the cooling water 24 supplied from the slit 42 and the water inlet 43 is preferably between 0.1 m / s and 0.7 m / s. When the cooling water 24 is supplied into the partition cylinder 32 from the slit 42 and the water inlet 43 at a flow velocity within this range, the cooling water 24 does not flow towards the core of the partition cylinder 32, but rather flows downwards along the inclined surface 34 from the upper end of the inclined surface 34. Thus, the cooling water 24 supplied from the upper cooling water pipe assembly 44 forms part of the first circulating flow, and the first circulating flow is stabilized. The cooling water volume supplied from the upper cooling water pipe assembly 44 is preferably 700 m³ / s. 3 / h or more 3000m 3 / h or less. If the cooling water supplied from the upper section of cooling water pipe group 44 is less than 700m³. 3 If the flow rate is less than 3000 m³ / h, it may not be able to stabilize the first circulation flow, therefore it is not preferred. 3 If the flow rate is reduced to a certain value per hour, the stabilizing effect of the first circulating flow will be saturated, and it will no longer contribute to the cooling of the granular iron 66. Instead, it will simply descend along the inclined surface 34 and be discharged from the drain port 22 at the lower end of the partition cylinder 32, which is therefore not preferred. The distribution of the cooling water supplied from the slit 42 and the water supply port 43 is preferably 6:4.

[0055] At least one set of water pipes of the lower section cooling water pipe assembly 48 is horizontally connected to the side of the pipe cylinder 35 opposite to the core of the pipe body 35. If cooling water 24 is supplied from the lower section cooling water pipe assembly 48 into the pipe cylinder 35, the cooling water 24 flows toward the core of the pipe cylinder 35, converges and rises at the core, generating a second circulating flow that circulates within the pipe cylinder 35.

[0056] The preferred cooling water volume supplied from the lower section cooling water pipe assembly 48 is 250 m³. 3 / h or above 750m 3 / h or less. If the cooling water supplied from the lower section of cooling water pipe group 48 is less than 250m³. 3 If the flow rate is less than 750 m³ / h, a second circulating flow within the pipe cylinder 35 is unlikely to occur, potentially creating a stagnant area with high water temperature, therefore it is not preferred. If the cooling water supply from the lower cooling water pipe assembly 48 exceeds 750 m³ / h... 3 If the flow rate is / h, it will hinder drainage from the lower end of the partition cylinder 32, and therefore is not preferred.

[0057] The flow rate of cooling water 24 supplied from the lower section cooling water pipe assembly 48 is preferably between 0.5 m / s and 1.0 m / s. If the flow rate of cooling water 24 supplied into the pipe cylinder 35 is slower than 0.5 m / s, the agitation effect within the pipe cylinder 35 will be reduced, which is therefore not preferred. If the flow rate of cooling water 24 supplied into the pipe cylinder 35 is faster than 1.0 m / s, leakage from the gap between the lower end of the pipe cylinder 35 and the conveying device 50 will increase, which is also not preferred.

[0058] Figure 2 This is a cross-sectional schematic diagram of the water flow control container 30, which is connected to the cooling water pipe assembly. Figure 2 (a) is a cross-sectional schematic diagram of the water flow control container 30 connected to the upper cooling water pipe assembly 44. Figure 2 (b) is a cross-sectional schematic diagram of the water flow control container 30 connected to the middle section cooling water pipe assembly 46. Figure 2 (c) is a cross-sectional schematic diagram of the water flow control container 30 connected to the lower cooling water pipe assembly 48.

[0059] like Figure 2As shown in (a), the upper cooling water pipe assembly 44 consists of two cooling water pipes 41. Cooling water 24 is supplied from the two cooling water pipes 41 to the water supply jacket 45, and distributed by the water supply jacket 45 to the annular slit 42 and 16 water inlets 43 radially arranged on the inclined surface 34 of the partition cylinder 32. Cooling water 24 is supplied into the partition cylinder 32 from the annular slit 42 and the 16 water inlets 43. The middle cooling water pipe assembly 46 consists of four cooling water pipes 41 arranged horizontally facing the core of the partition cylinder 32. Cooling water 24 is supplied into the partition cylinder 32 from the four cooling water pipes 41. The lower cooling water pipe assembly 48 consists of four cooling water pipes 41. Two of the four cooling water pipes 41 are arranged horizontally opposite each other facing the core of the pipe cylinder 35, and the other two cooling water pipes 41 are arranged on the side of the pipe cylinder. Cooling water 24 is supplied from four cooling water pipes 41 into the pipe cylinder 35. Thus, in the granulated iron manufacturing apparatus 70 according to this embodiment, cooling water is supplied from a total of ten cooling water pipes 41 into the partition cylinder 32 and the pipe cylinder 35. Figure 2 The example shown illustrates a quadrilateral cross-sectional shape for the pipe cylinder 35, but it is not limited to this; the cross-sectional shape of the pipe cylinder 35 can also be circular.

[0060] Figure 3 This is a cross-sectional schematic diagram illustrating the circulating flow generated within the partition cylinder 32 and the pipe cylinder 35. The first circulating flow B1 is the circulating flow that circulates within the partition cylinder 32. Cooling water 24 supplied from the intermediate cooling water pipe assembly 46 converges at the core of the cylinder, forming a strong upward flow. This strong upward flow extends towards the periphery near the inlet 33. The water flow extending to the periphery becomes a downward flow descending along the inclined surface 34. This downward flow merges with the cooling water flow from the slit 42 and the water supply port 43, and through the rectifying effect of these cooling water flows, flows downward along the inclined surface 34 and is discharged from the lower end connected to the pipe cylinder 35. Using the first circulating flow B1 within the partition cylinder 32, the water temperature in the cooling zone A from the middle to the upper section can be maintained at a suitable water temperature of approximately 50°C. The strong upward flow generated at the core of the partition cylinder 32 is a countercurrent to the granulated iron 66 that is introduced and descends from the inlet 33, thus enabling the granulated iron 66 to be cooled with high cooling efficiency.

[0061] The second circulating flow B2 is a circulating flow generated within the pipe cylinder 35. Drainage from the lower end of the partition cylinder 32 merges with a low-temperature jet of water from the lower cooling water pipe assembly 48, creating a swirling flow within the pipe cylinder 35. This allows for efficient cooling of the granular iron collected by the partition cylinder 32.

[0062] In this way, by generating a first circulating flow B1 within the partition cylinder 32 and a second circulating flow B2 within the pipe cylinder 35, the cooling water within the partition cylinder 32 and pipe cylinder 35 is stirred, which can suppress the formation of stagnant regions within the partition cylinder 32 and pipe cylinder 35. This suppresses localized temperature rises in the cooling water 24 within the partition cylinder 32 and pipe cylinder 35, thereby efficiently cooling the granular iron 66. As a result, it can prevent the granular iron 66 from being insufficiently cooled, thus preventing the granular iron from fusing and agglomerating together.

[0063] The upward flow generated in the core of the dividing cylinder 32 becomes a cooling water flow opposite to the granular iron 66 that is introduced and falls from the inlet 33, thus achieving high cooling efficiency. In order to properly form this upward flow, the total amount of cooling water supplied from the middle section cooling water pipe assembly 46 is preferably greater than the total amount of cooling water supplied from the upper section cooling water pipe assembly 44.

[0064] The cooling water flow supplied from the upper section cooling water pipe assembly 44, which is connected to the upper section of the inclined surface 34 of the partition cylinder 32, descends along the inclined surface 34 and thus collides with the jet flow from the middle section cooling water pipe assembly 46, which is connected to the middle section of the inclined surface 34 of the partition cylinder 32. Therefore, if the amount of cooling water supplied from the upper section cooling water pipe assembly 44 is greater than the amount of cooling water supplied from the middle section cooling water pipe assembly 46, the water flow from the middle section cooling water pipe assembly 46 will be weakened due to the flow of the cooling water, and it may be difficult to form the first circulation flow B1. Therefore, the total amount of cooling water supplied from the middle section cooling water pipe assembly 46 is preferably greater than the total amount of cooling water supplied from the upper section cooling water pipe assembly 44. Furthermore, the total amount of cooling water supplied from the middle section cooling water pipe assembly 46 is more preferably about four times the total amount of cooling water supplied from the upper section cooling water pipe assembly 44.

[0065] The total amount of cooling water supplied from the lower section cooling water pipe assembly 48 connected to the pipe cylinder 35 is preferably less than the total amount of cooling water supplied from the upper section cooling water pipe assembly 44. If the total amount of cooling water supplied from the lower section cooling water pipe assembly 48 is more than the total amount of cooling water supplied from the upper section cooling water pipe assembly 44, it will hinder the drainage from the lower end of the partition cylinder 32 to the pipe cylinder 35, and may even cause the temperature inside the partition cylinder 32 to rise. Therefore, the total amount of cooling water supplied from the lower section cooling water pipe assembly 48 is preferably less than the total amount of cooling water supplied from the upper section cooling water pipe assembly 44. Furthermore, the total amount of cooling water supplied from the lower section cooling water pipe assembly 48 is more preferably about half of the total amount of cooling water supplied from the upper section cooling water pipe assembly 44.

[0066] In order to properly generate the first circulating flow B1 and suppress the temperature rise inside the partition cylinder 32, it is preferable to reduce the total amount of cooling water supplied from each cooling water pipe group in the order of the middle section cooling water pipe group 46, the upper section cooling water pipe group 44, and the lower section cooling water pipe group 48. In this way, it is preferable to control the total amount of cooling water supplied from each cooling water pipe group as described above. Therefore, the granulated iron manufacturing apparatus 70 according to this embodiment preferably also includes a control device for controlling the total amount of cooling water supplied from the upper section cooling water pipe group 44, the middle section cooling water pipe group 46, and the lower section cooling water pipe group 48. This control device is composed of a general-purpose computer that controls cooling equipment such as heat exchangers and cooling towers (not shown), thereby controlling the supply of cooling water 24 to each cooling water pipe group.

[0067] The granular iron 66 cooled inside the water flow control container 30 is discharged from the outlet 36 located at the bottom of the water flow control container 30. The discharged granular iron 66 is then conveyed by the conveying device 50 to the outside of the cooling water tank 20.

[0068] Figure 4 This is a schematic diagram showing a portion of the conveying device 50. Figure 4 (a) is a side cross-sectional view showing a portion of the conveying device 50. Figure 4 (b) is a top view showing a portion of the water flow control container 30 and the conveying device 50. The conveying device 50 conveys the granular iron 66 discharged from the outlet 36 to outside the cooling water tank 20. The conveying device 50 includes a conveyor 52 for conveying the granular iron 66 to outside the cooling water tank 20, and a cooling water supply device 54 disposed above the conveyor 52.

[0069] The granular iron 66 discharged from outlet 36 accumulates on conveyor 52. Conveyor 52 transports the accumulated granular iron 66 outside the cooling water tank 20. In order to prevent the cooling water from being transported outside the cooling water tank 20 along with the granular iron 66, conveyor 52 is preferably a mesh conveyor.

[0070] The cooling water supply device 54 includes a main cooling water pipe 56 and multiple cooling water headers 57 arranged along the conveying direction of the conveyor 52. The main cooling water pipe 56 supplies cooling water from cooling equipment such as heat exchangers and cooling towers to the cooling water headers 57. The cooling water headers 57 are water pipes extending along the width direction of the conveyor 52. Multiple rectangular slits 58 are provided in the width direction of the cooling water headers 57, from which cooling water is supplied. The rectangular slits 58 are an example of a supply port. The supply port can be a rectangular slit of the same length as the length of the cooling water headers 57 extending along the width direction, or it can be multiple round nozzles arranged along the length direction. That is, at least one supply port needs to be provided in the width direction of the conveyor 52.

[0071] The rectangular slit 58 is preferably sized to prevent clogging caused by sludge mixed into the cooling water. The sludge mixed into the cooling water is approximately 1-2 mm in size; therefore, the length of the shorter side of the slit 58 is preferably 3 mm or more. The length of the longer side of the slit 58 is set to ensure a cooling water supply rate of 2-3 m / sec.

[0072] Multiple cooling water mains 57 are arranged in the conveying direction of the conveyor 52 and are respectively connected to the main cooling water pipes 56. The space 59, from which cooling water is supplied from the slits 58 of the cooling water mains 57, is the area above the granular iron 66 on the conveyor 52 and sandwiched between the conveyor 52 and the cooling water supply device 54. Cooling water, which has cooled the granular iron 66 discharged from the water flow control container 30 and become hot, is retained in this area. Therefore, by supplying cooling water to the space 59 through the cooling water supply device 54, convection of cooling water is generated within the space 59, and the hot cooling water is discharged from the space 59. As a result, the temperature of the cooling water around the granular iron 66 conveyed by the conveyor 52 can be kept low, the granular iron 66 accumulated on the conveyor 52 is cooled, and the melting and agglomeration of the granular iron 66 due to the surface temperature rising due to reheating can be suppressed.

[0073] Since cooling water can be supplied to a limited area above the conveyor 52 to cool the granular iron 66 collected on the conveyor 52, it is not necessary to convect the cooling water throughout the cooling water tank 20, and the granular iron 66 can be cooled efficiently with a small amount of cooling water.

[0074] The surface temperature of the iron granules 66 discharged from outlet 36 is approximately 800°C, thus the surface of the iron granules 66 is covered by a vapor film. If low-temperature cooling water is directly sprayed onto the iron granules 66, disrupting the vapor film and causing direct contact between the low-temperature cooling water and the surface of the iron granules 66, explosive boiling, i.e., a steam explosion, may sometimes occur. Therefore, to stably cool the iron granules 66, low-temperature cooling water is not directly sprayed onto them. Instead, it is preferable to maintain the temperature of the cooling water around the iron granules 66 in the range of 40°C to 65°C, and more preferably in the range of 45°C to 60°C. If the water temperature exceeds 65°C, the water easily boils, thus easily maintaining a vapor film around a high-temperature object, which can easily lead to film boiling, significantly reducing the cooling capacity of the iron granules. If the temperature is below 40°C, the vapor film covering the surface of the iron granules 66 becomes unstable, and a steam explosion may occur, which is therefore not preferred.

[0075] In the cooling water supply device 54, a plurality of cooling water mains 57 are arranged separately in the conveying direction of the conveyor 52, and a plurality of slits 58 are provided in the width direction of the conveyor 52. In this way, cooling water is supplied to the space 59 from the plurality of slits 58 of the plurality of cooling water mains 57 arranged along the conveying direction of the conveyor 52. As a result, the amount of cooling water supplied from each slit 58 can be reduced, direct spraying of cooling water onto the iron pellets 66 can be suppressed, and convection of cooling water can be generated within the space 59.

[0076] The supply velocity of cooling water supplied from the rectangular slit 58 is preferably in the range of 2 m / sec to 3 m / sec. By keeping the supply velocity of cooling water in the range of 2 m / sec to 3 m / sec, it is possible to suppress the increase of pressure loss in the cooling water main pipe 57 and the cooling water main pipe 56, and to generate convection of cooling water in the space 59, so that the high-temperature cooling water is discharged from the space 59.

[0077] Regarding the amount of cooling water supplied from the cooling water main 57, at least approximately 10 times the volume of space 59 should be supplied during the time until the granular iron 66 is conveyed by the conveying device 50 and moved out of the cooling water tank 20. This amount of cooling water supplied is determined based on simulation results described later.

[0078] Preferably, the spacing between the cooling water mains 57 is set to the same length as the spacing between the cooling water mains 57 and the granulated iron 66 conveyed on the conveyor 52. This prevents cooling water from stagnating between the cooling water mains 57, thereby uniformly reducing the cooling water temperature in the space 59. The temperature of the cooling water supplied from the cooling water mains 57 is preferably in the range of 30°C to 45°C. If the temperature of the cooling water supplied from the cooling water mains 57 is below 30°C, and the supplied cooling water is in direct contact with the surface of the granulated iron 66, an explosive boiling phenomenon, i.e., a steam explosion, may occur, which is therefore undesirable. If the temperature of the cooling water exceeds 45°C, the cooling effect on the granulated iron 66 decreases, which is also undesirable.

[0079] Figure 5 This is a cross-sectional schematic diagram showing another water flow control container 80 used in the granulated iron manufacturing apparatus according to this embodiment. Figure 5 In the water flow control container 80 shown, for the... Figure 1 The water flow control container 30 shown has the same structure labeled with the same reference numerals, and its description is omitted. Figure 5 The water flow control container 80 shown is similar in that it has a protrusion 90. Figure 1 The water flow control container 30 shown is different.

[0080] If a water inlet 43 for supplying cooling water 24 is provided on the inclined surface 34 of the partition cylinder 32, iron particles 66 falling along the inclined surface 34 may intrude into the water inlet 43 and cause blockage. Therefore, it is preferable to provide a protrusion 90 that covers the upper side of the connection between the water inlet 43 and / or the connection between the intermediate cooling water pipe assembly 46 and the inclined surface. Here, "covering the upper side of the connection between the water inlet 43 and the intermediate cooling water pipe assembly 46" means that the protrusion 90 is provided until the connection between the water inlet 43 and the intermediate cooling water pipe assembly 46 is obscured when viewed from above. The protrusion 90 is preferably configured to protrude horizontally from the inclined surface 34 into the partition cylinder 32 in a manner that does not obstruct the flow of the supplied cooling water 24.

[0081] Figure 6 This is a schematic diagram of the water inlet 43 with a protrusion, viewed from a horizontal perspective. Figure 6 (a) shows the inverted V-shaped protrusion 90. Figure 6 (b) shows the inverted U-shaped protrusion 91. (e.g.) Figure 6 As shown in (a), the cross-sectional shape of the protrusion 90 is preferably an inverted V-shape that protrudes upward and extends downward. By setting the cross-sectional shape of the protrusion 90 to an inverted V-shape, it is possible to suppress the accumulation of iron particles 66 on the upper surface of the protrusion 90 and to suppress the intrusion of iron particles 66 into the water supply port 43.

[0082] Alternatively, a protrusion 91 with an inverted U-shaped cross-section can be provided instead of the protrusion 90. By providing a protrusion 91 with an inverted U-shaped cross-section in this way, it is possible to suppress the accumulation of iron particles 66 on the upper surface of the protrusion 91 and to suppress the intrusion of iron particles 66 into the water supply port 43.

[0083] Figure 7 This is a cross-sectional schematic diagram showing another water flow control container 82 used in the granulated iron manufacturing apparatus according to this embodiment. Figure 7 In the water flow control container 82 shown, for the... Figure 5 The water flow control container 80 shown has the same structure labeled with the same reference numerals, and its description is omitted. Figure 7 The water flow control container 82 shown is similar in that it has a protective cover 92. Figure 5 The water flow control container 80 shown is different.

[0084] As described above, if a water supply port 43 is provided, the iron granules 66 falling along the inclined surface 34 may intrude into the water supply port 43 and cause blockage. In particular, the iron granules 66 in the upper section of the partition cylinder 32 are still in a molten state, so if they solidify inside the water supply port 43, they are difficult to remove. Therefore, it is more preferable to provide a protective cover 92 that covers the upper side of the water supply port 43. Here, covering the upper side of the water supply port 43 means that the protective cover 92 is provided until the water supply port 43 is obscured when viewed from above. As for the protective cover 92, it is preferable to provide the protective cover 92 in a position where the water supply port 43 is not obstructed when viewed from the horizontal direction, in a manner that does not obstruct the flow of cooling water 24 supplied from the water supply port 43. In addition, the protective cover 92 also covers the inclined surface 34 above the water supply port 43 along the inclined direction of the inclined surface 34. The upper end of the protective cover 92 is preferably designed to be closed in a way that prevents the flying droplets 64 from entering the protective cover 92, and the tilt angle of the protective cover 92 is preferably the same as that of the tilted surface 34.

[0085] Figure 8 This is a schematic diagram of the water inlet 43 with the protective cover 92 installed, viewed from a horizontal direction. (See diagram below.) Figure 8 As shown, the cross-sectional shape of the protective cover 92 is preferably a semi-circular or semi-elliptical shape that extends downwards. By setting the cross-sectional shape of the protective cover 92 to a semi-circular or semi-elliptical shape, it is possible to suppress the accumulation of iron particles 66 on the upper surface of the protective cover 92 and to suppress the intrusion of iron particles 66 into the water supply port 43.

[0086] Examples are shown where a protrusion 90 or a protective cover 92 is provided for the water supply port 43 in the water flow control containers 80 and 82, but this is not the only example; a protrusion 90 and a protective cover 92 may also be provided for the water supply port 43. Even with such a structure, the intrusion of iron particles 66 into the water supply port 43 can be suppressed.

[0087] As explained above, in the granulated iron manufacturing apparatus 70 of this embodiment, a first circulating flow B1 of cooling water 24 from bottom to top is generated in the partition cylinder 32, and a second circulating flow B2 of cooling water 24 from bottom to top is generated in the pipe cylinder 35. In the granulated iron manufacturing apparatus 70 of this embodiment, these two circulating flows are used to cool granulated iron 66, producing granulated iron 66 from molten iron 60. The first circulating flow B1 is a counter-current relative to the downward direction of the granulated iron 66, thus enabling efficient cooling of the granulated iron 66 using the first circulating flow B1. Furthermore, the circulation flows B1 and B2 agitate the spacer cylinder 32 and the pipe cylinder 35, thereby suppressing the formation of stagnant regions within the partition cylinder 32 and the pipe cylinder 35. As a result, the cooling effect of the granulated iron is improved, and the melting and agglomeration of the granulated iron particles during cooling is suppressed.

[0088] Furthermore, the granulated iron manufacturing apparatus 70 according to this embodiment has a conveying device 50 equipped with a cooling water supply device 54. Therefore, by replacing the cooling water in a limited area on the conveying device 50 that collects the granulated iron 66, the granulated iron 66 can be cooled efficiently. By cooling the granulated iron 66 in this way, the fusion and agglomeration of the granulated iron 66 conveyed by the conveyor 52 can be suppressed. In addition, the efficiency of cooling the granulated iron 66 with cooling water is also improved, so the amount of cooling water used can be reduced, and the large size of the equipment can also be prevented.

[0089] Example [Example 1] Next, as Example 1, the simulation results confirming the granulated iron cooling effect brought about by the granulated iron manufacturing apparatus according to this embodiment will be explained. (Production and...) Figure 1 The cooling water supply model shown is identical in structure to the water flow control container 30 configured within the cooling water tank 20. This model is used to simulate the water temperature distribution of the cooling water inside and around the water flow control container. The falling velocity and heat of the iron particles in the water and on the inclined surface within the separator cylinder are measured through prior experiments, thus modeling the positional distribution and heat generation of the iron particles within the separator cylinder and the pipe cylinder.

[0090] In the simulation results, if the cooling water temperature inside the separator cylinder, inside the pipe cylinder and around it is below 70°C, and the temperature is cooled to below 650°C when the granular iron accumulates on the conveying device, it is judged that the granular iron can be effectively cooled.

[0091] Figure 9 This is a diagram illustrating the simulation conditions of Invention Example 1 and Invention Example 2. Figure 10 This is a diagram illustrating the simulation conditions for Comparative Example 1 and Comparative Example 2. The cooling water supply models for Invention Example 1, Invention Example 2, Comparative Example 1, and Comparative Example 2 are set as follows: Figure 9 and Figure 10 The piping layout, number of pipes, cooling water flow distribution, and pipe diameter (nominal diameter (A)) shown were simulated. The cooling water pipe layout of Example 1 of the invention is similar to... Figure 2 The cooling water pipe layout of the water flow control container 30 shown is the same.

[0092] In the cooling water pipe layout of Invention Example 2, the cooling water pipe connected to the water supply jacket in the upper section of the cooling water pipe group is one, and the water pipe connected to the side of the pipe cylinder in the lower section of the cooling water pipe group is one less than that in Invention Example 1. Otherwise, the cooling water pipe layout is the same as that in Invention Example 1. In Invention Example 2, the cooling water flow distribution model is modified as follows: the total cooling water volume supplied from the middle section of the cooling water pipe group is set to approximately 40% of that in Invention Example 1, the cooling water volume supplied from the upper section of the cooling water pipe group is set to three times that of Invention Example 1, and the total cooling water volume supplied from the cooling water pipe group is set to be the same as that in Invention Example 1.

[0093] In Comparative Example 1, the model was set as follows: the upper and lower cooling water pipe assemblies were removed, and cooling water was supplied only using the middle cooling water pipe assembly. In Comparative Example 2, the cooling water flow distribution model was modified as follows: the number of pipes in the middle and lower cooling water pipe assemblies was reduced to less than half that of Invention Example 1, the amount of cooling water supplied was halved, and the amount of cooling water supplied from the upper cooling water pipe assembly was double that of Invention Example 1. The two pipes of the middle cooling water pipe assembly were connected to an inclined surface at a point symmetrical position with respect to the center of the horizontal cross-section of the dividing cylinder, in a manner that made the central axes of each cooling water pipe parallel.

[0094] Other common simulation conditions in Invention Example 1, Invention Example 2, Comparative Example 1, and Comparative Example 2 are as follows.

[0095] (1) Temperature of molten iron: 1500℃ (2) The flow rate of molten iron from the tundish: 450 tons / h (3) Cooling water temperature: 35℃ (4) Inclination angle of the inclined surface of the dividing cylinder: 56° (5) Diameter of the outlet of the partition cylinder: 1560mm (6) Height of the partition cylinder: 3300mm (7) Height of the inclined surface of the partition cylinder: 3291mm (Length of the inclined surface: 3970mm) Figure 11 This is a diagram showing the simulation results of Invention Example 1 and Invention Example 2. (As shown...) Figure 11 As shown in Invention Example 1, the cooling water temperature inside the water flow control container is 52~69°C, achieving the target of below 70°C. Furthermore, the maximum temperature of the granular iron when it accumulates on the conveying device is 550°C, also achieving the target temperature of the granular iron (below 650°C).

[0096] Figure 12 This is a three-dimensional schematic diagram showing the flow of cooling water supplied from each cooling water pipe assembly in Example 1 of the invention. Figure 12 (a) is a three-dimensional schematic diagram showing the flow of cooling water supplied from the upper cooling water pipe assembly. Figure 12 (b) is a three-dimensional schematic diagram showing the flow of cooling water supplied from the middle section cooling water pipe assembly. Figure 12 (c) is a three-dimensional schematic diagram showing the flow of cooling water supplied from the lower section of the cooling water pipe assembly. Figure 12 As shown in (a) and (b) of the figures, it is confirmed that a first circulating flow is generated within the partition cylinder in the invention example. According to... Figure 12 (c) confirms that, in the inventive example, a second circulating flow is generated within the pipe cylinder.

[0097] Refer again Figure 11 In Invention Example 2, although the cooling water volume from the intermediate cooling water pipe assembly was reduced to 40%, an upward flow was generated in the core. Furthermore, a strong water flow descending from the upper cooling water pipe assembly along the inclined surface of the dividing cylinder was generated, particularly on the side where the cooling water pipe connects to the water supply jacket (the right side of the paper). As a result, the first circulation flow was stabilized, the cooling water was stirred, and the cooling water temperature in the water flow control container was maintained below 70°C, achieving the target of below 70°C. In addition, the maximum temperature of the granular iron accumulating on the conveying device was 646°C, also achieving the target granular iron temperature (below 650°C). Comparing the temperatures of the granular iron accumulating on the conveying device in Invention Example 1 and Invention Example 2, the total cooling water volume supplied from the intermediate cooling water pipe assembly was greater than that supplied from the upper cooling water pipe assembly in Invention Example 1, by approximately 100°C. The results confirm that by supplying more total cooling water from the middle section cooling water pipe assembly than from the upper section cooling water pipe assembly, granular iron can be cooled with high cooling efficiency.

[0098] Figure 13 This is a graph showing the simulation results for Comparative Example 1 and Comparative Example 2. (See figure below.) Figure 13 As shown, in Comparative Example 1, a large amount of cooling water was supplied from the middle section cooling water pipe assembly, thus generating a strong upflow. The cooling water was agitated by this upflow, and the cooling water temperature in the central part of the separator was maintained below 70°C. However, in the upper and lower parts of the separator, the cooling water was not agitated, and stagnation occurred in these areas. Consequently, the temperature of the granular iron accumulating on the conveying device reached 652°C, slightly exceeding the target (below 650°C).

[0099] In Comparative Example 2, the two pipes of the intermediate cooling water pipe assembly were connected to an inclined surface at a point symmetrical with respect to the center of the horizontal cross-section of the partition cylinder, with the central axes of each cooling water pipe parallel. This method connected the cooling water pipes to the partition cylinder. Therefore, unlike Invention Example 1 and Comparative Example 1, a strong upward flow near the cylinder core was not generated; instead, a rotating flow that rises while rotating within the partition cylinder was generated. The water temperature within the partition cylinder of Comparative Example 2 was lower than that of Invention Example 1 and Comparative Example 1. This indicates that the heat of the granulated iron was not effectively dissipated; the maximum temperature of the granulated iron accumulated on the conveying device was 700°C, significantly exceeding the target (below 650°C), and the temperature deviation of the granulated iron was also large, ranging from 460°C to 700°C. Based on the above simulation results, it was confirmed that the granulated iron manufacturing apparatus according to this embodiment can efficiently cool the granulated iron.

[0100] Next, regarding Figure 5 and Figure 7The water flow control containers 80 and 82 shown illustrate the results of confirming whether granular iron has entered the water supply port 43. Figure 14 This is a diagram showing the results of confirming whether granular iron has entered the water supply port 43. Invention Example 3 is... Figure 5 The water flow control container 80 shown is, in Invention Example 4, Figure 7 The water flow control container 82 shown.

[0101] In Invention Example 3, a protrusion 90 is provided covering the upper side of the water supply port 43, thus suppressing the intrusion of granular iron into the water supply port 43. This confirms that cooling water 24 can be supplied from the water supply port 43 without being blocked by granular iron, and that granular iron can be cooled and manufactured using the water flow control container 80 with high cooling efficiency.

[0102] In Example 4, a protective cover 92 is provided covering the upper side of the water supply port 43, thus preventing the intrusion of granular iron into the water supply port 43. This confirms that cooling water 24 can be supplied from the water supply port 43 without being blocked by granular iron, and that granular iron can be cooled and manufactured using the water flow control container 82 with high cooling efficiency.

[0103] [Example 2] Next, as Example 2, the simulation results confirming the cooling effect of the granulated iron 66 brought about by the conveying device 50 of the granulated iron manufacturing apparatus 70 according to this embodiment will be explained. Figure 15 This is a schematic diagram of the granulated iron manufacturing apparatus 70 used in the simulation. Figure 15 (a) is a perspective view of the granulated iron manufacturing apparatus 70. Figure 15 (b) is a side view of the granulated iron manufacturing apparatus 70.

[0104] The simulation conditions are as follows.

[0105] Cooling water main pipe inner diameter: 200A Length of cooling water main pipe: 5m Distance from the main cooling water pipe to the upper surface of the conveyor: 750mm Cooling water main pipe inner diameter: 50A Length of cooling water main pipe: 1m Distance from the main cooling water pipe to the iron pellets on the conveyor: 250mm Distance between the main cooling water pipes: 250mm Number of cooling water mains: 20 Slit shape: Rectangular (3mm × 20mm) Spacing between slits: 10mm Number of slits in a single cooling water main: 30 Cooling water supply rate: 3 m / s Cooling water temperature: 35℃ Cooling water supply flow rate to cooling water main pipe 56: 390m³ 3 / h (Cooling water supply for 5 minutes: 33m³) 3 ) Conveyor width: 1m Conveyor speed: 1m / min Volume of the space between the upper surface of the conveyor and the cooling water supply device: 3.6m³ 3 Initial water temperature in the cooling water tank: 65℃ Surface temperature of granulated iron 66: 700℃ Figure 16 This is a diagram showing the results of a simulation of the water temperature within space 59 when cooling water is supplied from cooling water supply device 54 to space 59. Figure 16 In this process, cooling water at a temperature of 35°C is supplied from a 5m long cooling water supply device 54 located above the conveyor 52 to the space 59 sandwiched between the conveyor 52 and the cooling water supply device 54. Particles of iron 66 discharged from the outlet 36 of the water flow control container 30 and accumulated on the conveyor 52 are conveyed from the bottom of the cooling water tank 20 at a conveying speed of 1m / min for 5 minutes. During the 5 minutes that the particles of iron 66 are conveyed under the cooling water supply device 54, the cooling water supply from the cooling water main pipe 56 to the cooling water header 57 is 33m³. 3 (The supply flow rate of cooling water to the cooling water main pipe 56 is 390m³) 3 / h). This is the volume of the space between the upper surface of the conveyor 52 and the cooling water supply device 54 (3.6m³). 3 Approximately 10 times that of the space 59. By supplying cooling water from the cooling water supply device 54 to the space 59, the initial water temperature is 65°C, and the water temperature in the space 59 sandwiched between the conveyor 52 and the cooling water supply device 54 drops to 50-58°C. It has been confirmed that by using the granulated iron manufacturing apparatus 70 according to this embodiment, the water temperature in the space 59 sandwiched between the conveyor 52 and the cooling water supply device 54 can be maintained in the range of 45°C to 60°C.

[0106] Figure 17 This is a graph showing the results of simulating the temperature of the iron particles on the conveyor 52. The temperature change of the object 66', which is located on the conveyor 52 and has iron particles 66 at a simulated high temperature of 700°C, was also simulated. Figure 17 (a) is a side cross-sectional view showing the temperature of object 66' before cooling. Figure 17 (b) is a front cross-sectional view showing the temperature of object 66' before cooling. Figure 17(c) is a front cross-sectional view showing the temperature of object 66' after 10 seconds of being supplied with cooling water.

[0107] like Figure 17 As shown, by supplying cooling water from the slit, the high-temperature object 66' is cooled, and 10 seconds after the cooling water is supplied, the surface temperature of the high-temperature object at 700°C drops to about 400°C. This confirms that by using the granulated iron manufacturing apparatus 70 according to this embodiment, the surface temperature of the granulated iron 66 can be cooled from 700°C to about 400°C, and the melting and agglomeration of the granulated iron 66 accumulated on the conveyor 52 can be suppressed.

[0108] Explanation of reference numerals in the attached figures 10 Granulation device 12 Intermediate Packages 14 Molten Iron Receiving Pan 16 nozzles 18 Support body 20 cooling water tank 22 Drain outlet 24 Cooling water 30 Water flow control container 32. Separating cylinder 33 Input Port 34 Inclined surface 35 Pipeline body 36 discharge outlets 40 Cooling water pipe assembly 41 Cooling water pipe 42 Slits 43 Water supply outlet 44 Upper section cooling water pipe assembly 45 Water supply units 46. ​​Mid-section cooling water pipe assembly 48 Lower section cooling water pipe assembly 50 conveying device 52 Conveyor 54 Cooling water supply device 56 Cooling water main pipe 57 Cooling water main pipe 58 Slits 59 Space 60 molten iron 62 liquid column 64 droplets 66 iron grains 66' object 70-piece iron manufacturing device 80 Water Flow Control Container 82 Water Flow Control Container 90 Protrusion 91. Protrusion 92 Protective Cover

Claims

1. A pelletized iron manufacturing apparatus, comprising: a pelletizing device for forming molten iron into droplets; a cooling water tank for cooling the droplets in cooling water to form pelletized iron; and a conveying device for conveying the pelletized iron outside the cooling water tank. The granulated iron manufacturing apparatus includes: a water flow control container disposed within the cooling water tank and open at both ends; and a cooling water pipe assembly for supplying cooling water to the water flow control container. The water flow control container includes: a partition cylinder having an inclined surface that narrows downwards in a manner that causes the horizontal cross-sectional area to decrease; and a pipe cylinder connected to the lower part of the partition cylinder. The cooling water pipe assembly includes: an upper section cooling water pipe assembly and a middle section cooling water pipe assembly connected to the partition cylinder; and a lower section cooling water pipe assembly connected to the pipe cylinder. The upper section of the cooling water pipe assembly is connected to the upper section of the inclined surface containing the upper end of the partition cylinder. Cooling water supplied from the upper section of the cooling water pipe assembly generates a cooling water flow from top to bottom along the inclined surface. The intermediate cooling water pipe assembly is horizontally connected to the core of the partition cylinder at the middle section of the inclined surface of the partition cylinder. Cooling water supplied from the intermediate cooling water pipe assembly generates a first circulating flow. This first circulating flow flows towards the core of the partition cylinder, converges and rises at the core, and circulates within the partition cylinder along the inclined surface from top to bottom. The lower section of the cooling water pipe assembly is connected to the side of the pipe cylinder, and a second circulating flow is generated within the pipe cylinder using the cooling water supplied from the lower section of the cooling water pipe assembly and the drainage from the partition cylinder. The conveying device includes: a conveyor disposed below the water flow control container and conveying the granular iron from inside the cooling water tank to outside the cooling water tank; and a cooling water supply device disposed above the conveyor in the cooling water tank and supplying cooling water to cool the granular iron conveyed by the conveyor.

2. The granulated iron manufacturing apparatus as claimed in claim 1, further comprising a control device for controlling the amount of cooling water supplied from the cooling water pipe assembly to the water flow control container. The control device controls the amount of cooling water supplied from the cooling water pipe assembly to decrease in the order of the middle section cooling water pipe assembly, the upper section cooling water pipe assembly, and the lower section cooling water pipe assembly.

3. The granulated iron manufacturing apparatus as described in claim 1 or 2, wherein, The cooling water supply device includes: a main cooling water pipe that supplies cooling water to the area above the granulated iron on the conveyor and is arranged along the conveying direction of the conveyor; and a plurality of cooling water manifolds arranged in the conveying direction and respectively connected to the main cooling water pipe, wherein the cooling water manifolds extend along the width direction of the conveyor and are provided with at least one supply port in the width direction.

4. The granulated iron manufacturing apparatus as described in claim 1, wherein, It has a protrusion that covers the upper side of the connection between the upper section cooling water pipe assembly and / or the middle section cooling water pipe assembly and the inclined surface.

5. The granulated iron manufacturing apparatus as described in claim 4, wherein, The cross-sectional shape of the protrusion is an inverted V-shape or an inverted U-shape that extends from top to bottom.

6. The granulated iron manufacturing apparatus according to any one of claims 1, 4, and 5, wherein, It has a protective cover that covers the upper side of the connection between the upper section of the cooling water pipe assembly and the inclined surface, and the upper end of the protective cover is closed.

7. The granulated iron manufacturing apparatus as described in claim 6, wherein, The protective cover has a cross-sectional shape that is a semicircle or semi-ellipse that expands from top to bottom.

8. The granulated iron manufacturing apparatus as described in claim 3, wherein, The supply port is a rectangular slit with a short side length of 3mm or more.

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