Granular iron manufacturing device and granular iron manufacturing method

Abstract

Provided are a granular iron manufacturing device and a granular iron manufacturing method with which it is possible to efficiently cool granular iron and suppress the combination of the granular iron. The granular iron manufacturing device (70) is provided with a water flow control container (30) and a cooling water pipe group (40) for supplying cooling water (24) into the water flow control container, and the water flow control container (30) is provided with a partition cylinder body (32) with an inclined surface (34) and a pipeline cylinder body (35) connected to the lower portion of the partition cylinder body (32). The cooling water pipe group (40) has an upper-stage cooling water pipe group (44), a middle-stage cooling water pipe group (46), and a lower-stage cooling water pipe group (48) that are connected to the partition cylinder (32), and generates a first circulation flow that circulates in the partition cylinder (32) by means of cooling water (24) supplied from the middle-stage cooling water pipe group (46) and the upper-stage cooling water pipe group (44). A second circulation flow circulating in the pipe cylinder (35) is generated by cooling water (24) supplied from the lower-stage cooling water pipe group (48) and drainage from the partition cylinder (32).

Description

Technical Field

[0001] The present invention relates to a granular iron manufacturing device and a granular iron manufacturing method for manufacturing granular iron using molten iron. Background Art

[0002] Granulated iron is obtained by dispersing molten iron such as molten iron and molten steel and solidifying it into granules, and its average particle size is about several mm to tens of mm. In a conventional ironmaking plant of steel, when a failure occurs in a process below steelmaking, or when the molten iron produced by the blast furnace suddenly becomes excessive, it is temporarily stored in granulated iron. In recent years, blast furnaces have become larger, and if they cannot temporarily handle a large amount of molten iron, the blast of the blast furnace will be reduced. Therefore, in preparation for failures in processes below steelmaking, equipment that serves as a buffer is required.

[0003] In addition, due to the recent CO 2 The need to reduce emissions has led to an increase in demand for reduced iron produced using hydrocarbon gases such as hydrogen or natural gas instead of coke (carbon source) as a reducing agent. 2 、Al 2 O 3 ) and the manufacture of steel products with reduced iron having a high phosphorus concentration. After the manufacture of reduced iron, gangue removal and dephosphorization are indispensable. Therefore, as a pre-treatment for the manufacture of steel products, the reduced iron is sometimes melted once to form molten iron, and then gangue removal and dephosphorization are performed to make the molten iron into transportable granular iron and store it.

[0004] As a method of granulating molten iron, Patent Document 1 discloses a method of granulating the molten iron by blowing pressurized water onto the molten iron. However, in the method disclosed in Patent Document 1, the granular iron often becomes hollow, and water accumulates in the hollow part, which poses a risk of causing a water vapor explosion during remelting. Patent Document 2 discloses a method for manufacturing granular metal as follows: molten iron is dropped onto a fixed plate, and the droplets bounce off the fixed plate and fall into a cooling bath on the lower side to be cooled, thereby manufacturing granular iron. In addition, Patent Document 3 discloses a device that granulates molten iron using a water flow, drops liquid granular iron into water to cool and solidify it, and manufactures a large amount of granular iron.

[0005] The granules are at high temperature when put into water. The temperature of the granules is about 1200~1500℃. Therefore, if such high-temperature granules come into contact with water, a film boiling state in which a steam film is generated on the surface of the high-temperature object is formed, and the water evaporates, gradually taking away the heat of the granules. The cooling capacity of this film boiling is low, for example, the heat transfer rate is only about a few hundredths of that of nucleate boiling in which no steam film is generated. Therefore, if film boiling continues for a long time, the granules are not cooled sufficiently, and sometimes the granules fuse and merge in the cooling water.

[0006] In addition, if the cooling water temperature is high, the water is easy to boil, so it is easy to maintain a steam film around the high-temperature object, and film boiling is easy to occur. Therefore, if the water temperature of the cooling water becomes high, the cooling capacity of the granular iron is significantly reduced, and the granular iron is easy to be combined. In order to solve such a problem, Patent Document 3 considers that by adjusting the cooling water volume of the secondary cooling water and maintaining the cooling water temperature in the pit at 68°C or less, it is possible to suppress the combination of granular iron accumulated in the pit.

[0007] Prior art literature

[0008] Patent Literature

[0009] Patent Document 1: Japanese Patent Application Publication No. 2018-115363

[0010] Patent Document 2: Japanese Patent Publication No. 52-20948

[0011] Patent Document 3: Japanese Patent Application Laid-Open No. 9-20902 Summary of the invention

[0012] Problems to be solved by the invention

[0013] Considering the installation space of the granular iron conveying device, in which the droplets of molten iron expand and solidify to a certain extent in the horizontal direction when the granular iron is produced from molten iron, a cooling water tank of considerable size is required for cooling the granular iron. The cooling water tank is provided with a spray port for supplying cooling water and a drain port for conveying the cooling water after the temperature rises to the cooling device, so that the cooling water circulates to the cooling water tank and the cooling device.

[0014] However, it is difficult to control the relatively cold cooling water so that it spreads throughout the larger 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 there is no description of a method for controlling the flow in the cooling water tank. Depending on the flow of the cooling water, stagnant areas may sometimes occur in the cooling water tank. If the relatively warm cooling water used to cool the granular iron is retained in the stagnant area, areas with relatively high water temperatures may sometimes appear locally. If a large amount of granular iron is added to the area with relatively high water temperatures, the film boiling state is maintained for a long time and the granular iron is not sufficiently cooled, and the granular iron will fuse and combine with each other. If the granular iron combines with each other, the size of the granular iron that is not easy to transport increases and transportation becomes difficult. In addition, there is the following problem: if the granular iron contains cooling water when it combines with each other, it will cause a steam explosion.

[0015] The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a granular iron manufacturing apparatus and a granular iron manufacturing method capable of efficiently cooling molten iron and suppressing the fusion of granular iron.

[0016] Means for solving problems

[0017] The gist of the present invention that can solve the above-mentioned problems is as follows.

[0018] [1] A granulated iron manufacturing device, comprising a granulating device and a cooling water tank, wherein the granulating device converts molten iron into droplets, and the cooling water tank causes the droplets to fall into cooling water to cool the droplets, wherein the granulated iron manufacturing device comprises a water flow control container and a cooling water pipe group, wherein the water flow control container is arranged in the cooling water tank and has upper and lower ends opened, and the cooling water pipe group supplies cooling water into the water flow control container, and the water flow control container comprises a partition cylinder and a pipe cylinder, wherein the partition cylinder has an inclined surface inclined in a manner that narrows the horizontal cross-sectional area downward, and the pipe cylinder is connected to the bottom of the partition cylinder, and the cooling water pipe group comprises an upper cooling water pipe group and a middle cooling water pipe group connected to the partition cylinder, and a lower cooling water pipe group connected to the pipe cylinder, wherein the upper cooling water The tube group is connected to the upper section of the inclined surface including the upper end of the partition cylinder, and uses the cooling water supplied from the upper cooling water tube group to generate a cooling water flow along the inclined surface from top to bottom. The middle cooling water tube group is horizontally connected to the middle section of the inclined surface of the partition cylinder toward the center of the partition cylinder, and uses the cooling water supplied from the middle cooling water tube group to generate a first circulation flow. The first circulation flow goes to the center of the partition cylinder, merges and rises at the center, and circulates in the partition cylinder accompanied by the cooling water flow along the inclined surface from top to bottom. The lower cooling water tube group is connected to the side of the pipe cylinder, and uses the cooling water supplied from the lower cooling water tube group and the drainage from the partition cylinder to generate a second circulation flow circulating in the pipe cylinder.

[0019] [2] According to the granular iron manufacturing device described in [1], the granular iron manufacturing device also has a conveying device, which is arranged below the water flow control container and conveys the granular iron cooled in the water flow control container to the outside of the cooling water tank.

[0020] [3] The granular iron manufacturing device according to [1] or [2] comprises a control device for controlling the amount of cooling water supplied from the cooling water pipe group to the water flow control container, wherein the control device controls the amount of cooling water supplied from the cooling water pipe group in such a manner that the amount of cooling water supplied from the cooling water pipe group decreases in the order of the middle cooling water pipe group, the upper cooling water pipe group, and the lower cooling water pipe group.

[0021] [4] According to any one of [1] to [3], the granular iron manufacturing device has a protrusion, which covers the upper side of the connection portion where the upper cooling water pipe group is connected to the inclined surface and / or the upper side of the connection portion where the middle cooling water pipe group is connected to the inclined surface.

[0022] [5] The granular iron production device according to [4], wherein the cross-sectional shape of the protrusion is an inverted V shape or an inverted U shape extending from the upper side to the lower side.

[0023] [6] According to any one of [1] to [5], the granular iron manufacturing device has a protective cover, which covers the upper side of the connection portion where the upper cooling water pipe group is connected to the inclined surface, and the upper end of the protective cover is closed.

[0024] [7] According to the granular iron production device described in [6], the cross-sectional shape of the protective cover is a semicircular or semi-elliptical shape that expands from the top to the bottom.

[0025] [8] A method for manufacturing granular iron, which is a method for manufacturing granular iron using the granular iron manufacturing device described in any one of [1] to [7], wherein the amount of cooling water supplied from the cooling water pipe group decreases in the order of the middle cooling water pipe group, the upper cooling water pipe group, and the lower cooling water pipe group.

[0026] Effects of the Invention

[0027] In the granular iron manufacturing device of the present invention, a first circulation flow of cooling water from the bottom to the top is generated in the partition cylinder, and a second circulation flow of cooling water from the bottom to the top is generated in the pipe cylinder, and the granular iron is cooled by the circulation flow. As a result, the cooling efficiency of the granular iron in the partition cylinder is improved, and the granular iron can be prevented from fusing and combining with each other when the granular iron is cooled. In addition, by improving the cooling efficiency of the granular iron, if the cooling capacity of the granular iron is the same, it can become a more compact device, and if the size of the device is the same, it can become a device that can produce more granular iron. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic cross-sectional view of the granular iron production apparatus according to the present embodiment.

[0029] Figure 2 It is a cross-sectional schematic diagram of a water flow control container connected to a portion of a cooling water pipe group.

[0030] Figure 3 It is a cross-sectional schematic diagram illustrating the circulation flow generated in the partition cylinder and the pipe cylinder.

[0031] Figure 4 1 is a schematic cross-sectional view showing another water flow control container used in the granular iron production apparatus according to the present embodiment.

[0032] Figure 5 This is a schematic diagram of a water supply port provided with a protruding portion when viewed from a horizontal direction.

[0033] Figure 61 is a schematic cross-sectional view showing another water flow control container used in the granular iron production apparatus according to the present embodiment.

[0034] Figure 7 This is a schematic diagram of a water supply port provided with a protective cover when viewed from a horizontal direction.

[0035] Figure 8 It is a diagram showing the simulation conditions of Invention Example 1 and Invention Example 2.

[0036] Fig. 9 It is a figure which shows the simulation conditions of Comparative Example 1 and Comparative Example 2.

[0037] Fig.10 It is a figure which shows the simulation result of the example 1 of invention and the example 2 of invention.

[0038] Fig.11 This is a schematic perspective view showing the flow of cooling water supplied from each cooling water pipe group in Inventive Example 1.

[0039] Fig.12 It is a figure which shows the simulation result of Comparative Example 1 and Comparative Example 2.

[0040] Fig.13 This is a diagram showing the result of checking the presence or absence of intrusion of granular iron into the water supply port. DETAILED DESCRIPTION

[0041] Hereinafter, the present invention will be described by way of embodiments of the invention. Figure 1 1 is a schematic cross-sectional view of a granular iron manufacturing device 70 of the present embodiment. The granular iron manufacturing device 70 is a device for cooling and solidifying molten iron such as molten iron or molten steel in a droplet state, thereby manufacturing granular iron material, i.e., granular iron. The granular iron manufacturing device 70 includes a granulating device 10 for making molten iron into droplets, a cooling water tank 20, a water flow control container 30, a cooling water pipe group 40, and a conveying device 50.

[0042] The granulation device 10 includes a tundish 12 (molten iron bucket, etc.) containing molten iron 60 and having a nozzle 16 for ejecting molten iron at the bottom, and a molten iron receiving pan 14 for colliding with a liquid column 62 of molten iron ejected from the nozzle 16. The molten iron receiving pan 14 is made of a disc-shaped refractory material and is supported by a support body 18. The liquid column 62 of molten iron flowing from the nozzle 16 collides with the molten iron receiving pan 14, and droplets 64 of the molten iron 60 are scattered around it.

[0043] If the droplets 64 of the molten iron 60 become larger, the heat capacity becomes larger and solidification takes time. The molten iron 60 may fuse and combine with each other in the water flow control container 30 under high temperature, and may become a large block that is not easy to transport. Therefore, the granulating device 10 preferably makes the molten iron 60 become droplets 64 with a maximum length of granular iron 66 of 50 mm or less after cooling. The molten iron 60 passes through the granulating device 10 and becomes droplets 64, which fall toward the cooling water 24. In addition, in the granulating device 10, the amount of the molten iron 60 flowing down from the tundish 12 is controlled in such a way that the droplets 64 fall toward the area where the water flow control container 30 is provided.

[0044] The cooling water tank 20 contains cooling water 24 and a water flow control container 30. The water flow control container 30 is provided in the cooling water 24 contained in the cooling water tank 20. The cooling water 24 contained in the cooling water tank 20 may include the cooling water 24 discharged from the water flow control container 30. The cooling water 24 contained in the cooling water tank 20 is discharged from the drain port 22 in an amount equal to the amount of cooling water supplied so that the cooling water level of the cooling water tank 20 is constant. It should be noted that by using a large-capacity cooling water tank 20, it is easy to control the cooling water level, and the production of granulated iron by the granulated iron production device 70 is stable.

[0045] The water flow control container 30 is provided in the cooling water tank 20 and is provided at a position to receive the molten iron that has become droplets after passing through the granulating device 10. The water flow control container 30 cools and solidifies the droplets into granular iron 66 using the cooling water 24 contained therein.

[0046] The water flow control container 30 includes a partition cylinder 32 having an inclined surface 34 inclined in such a manner that the horizontal cross-sectional area becomes narrower toward the downward direction, and a pipe cylinder 35 connected to the lower part of the partition cylinder 32. An inlet 33 for receiving liquid droplets 64 is provided at the upper end of the partition cylinder 32, and a discharge port 36 for discharging granular iron is provided at the lower end of the pipe cylinder 35. That is, the upper and lower ends of the water flow control container 30 are open. The inclined surface 34 only needs to be formed on the inner side of the water flow control container 30, and the shape of the outer side of the water flow control container 30 is not particularly limited. The inclination angle of the inclined surface 34 is preferably set to an angle in the range of 40 to 60 degrees from the viewpoint of preventing the granular iron 66 from being retained. In addition, in Figure 1 In the illustrated example, an example is shown in which the water flow control container 30 has no cylindrical portion on the upper end side, but the water flow control container 30 may have a cylindrical portion on the upper end side.

[0047] In the present embodiment, the cooling region of the granular iron 66 formed by the water flow control container 30 is referred to as the cooling region A. The reason for providing the cooling region A formed by the water flow control container 30 is to obtain the following two effects.

[0048] (1) By centrally introducing the cooling water 24 into the cooling area A, the granular iron 66 can be efficiently cooled.

[0049] (2) The iron granules 66 generated in the partition cylinder 32 can be collected at one place by the inclined surface 34, so that the iron granules 66 can be easily recovered.

[0050] The cooling water pipe group 40 is a water pipe group through which the cooling water 24 cooled to a temperature of 0°C or higher and 35°C or lower by a cooling device such as a heat exchanger or a cooling tower (not shown) flows. When the cooling water 24 is supplied from the cooling water pipe group 40 to the partition cylinder 32 of the water flow control container 30, the cooling water 24 flows toward the upper side where the opening is larger. Therefore, when the cooling water is supplied from the lower side of the partition cylinder 32 toward the cylinder center, the cooling water converges and rises at the cylinder center in the partition cylinder 32. On the other hand, when the cooling water is supplied from the upper side of the partition cylinder 32 toward the lower side along the inclined surface 34, the cooling water 24 converges and rises at the cylinder center in the partition cylinder 32, instead of flowing out from the inlet 33 of the partition cylinder 32 into the cooling water tank 20, the cooling water 24 expands in the circumferential direction near the inlet 33, thereby generating a first circulation flow accompanied by the cooling water flow descending on the inclined surface 34 of the partition cylinder 32. By generating this first circulation flow, the granulated iron 66 can be cooled by the reverse flow, and the stagnant area in the partition cylinder 32 can be reduced. The cooling water pipe group 40 includes an upper cooling water pipe group 44 and a middle cooling water pipe group 46 connected to the partition cylinder, and a lower cooling water pipe group 48 connected to the pipe cylinder 35 .

[0051] The middle cooling water pipe group 46 is horizontally connected to the middle section of the inclined surface 34 ranging from the center of the partition cylinder 32 in the vertical direction to 650 mm below, toward the cylinder center of the partition cylinder 32. If the cooling water 24 is supplied to the partition cylinder 32 from the middle cooling water pipe group 46, the cooling water 24 goes to the cylinder center of the partition cylinder 32, merges at the cylinder center and rises. The cooling water 24 that has merged and risen at the cylinder center expands in the circumferential direction at the upper end of the partition cylinder 32, flows in a manner descending along the inclined surface 34, and forms a first circulation flow. The cooling water 24 supplied from the middle cooling water pipe group 46 forms a part of the first circulation flow.

[0052] The amount of cooling water supplied from the middle cooling water pipe group 46 is preferably 1500m 3 / h and above and 3900m 3 / h or less. If the cooling water volume is less than 1500m 3 / h, it is not easy to generate a strong and stable upward flow at the center of the partition cylinder 32, so it is not desirable. In addition, if the cooling water volume exceeds 3900m 3 / h, the cooling water 24 deviates from the first circulation flow and flows out from the inlet 33 of the partition cylinder 32 to the cooling water tank 20, which is undesirable.

[0053] The flow rate of the cooling water 24 supplied from the middle cooling water pipe group 46 is preferably 1.8 m / s or more and 2.2 m / s or less. If the flow rate of the cooling water 24 supplied from the middle cooling water pipe group 46 is slower than 1.8 m / s, the cooling water 24 will decelerate before reaching the core of the partition cylinder 32, and it is not easy to generate a strong and stable upward flow, which is undesirable. In addition, if the flow rate of the cooling water 24 supplied from the middle cooling water pipe group 46 is faster than 2.2 m / s, the pressure loss at the cooling water pipe 41 becomes high, and large-scale water supply equipment such as pumps is required, which is undesirable.

[0054] The upper cooling water pipe group 44 is connected to the upper part of the inclined surface 34 including the upper end of the partition cylinder 32. The upper cooling water pipe group 44 is connected to a water supply jacket 45, which covers the upper part of the partition cylinder 32 including a slit 42 having a predetermined gap at the periphery of the upper end of the partition cylinder 32 and a water supply port 43 on the inclined surface 34 of the upper part of the partition cylinder 32, and supplies cooling water to the slit 42 and the water supply port 43. The upper cooling water pipe group 44 is connected to the inclined surface 34 including the upper end of the partition cylinder 32 in the range from the upper end of the partition cylinder 32 to 1000m below.

[0055] The flow rate of the cooling water 24 supplied from the slit 42 and the water supply port 43 is preferably greater than 0.1 m / s and less than 0.7 m / s. If the cooling water 24 is supplied from the slit 42 and the water supply port 43 to the partition cylinder 32 at a flow rate within this range, the cooling water 24 does not flow toward the core of the partition cylinder 32, but flows from the upper end of the inclined surface 34 to the bottom along the inclined surface 34. As a result, the cooling water 24 supplied from the upper cooling water pipe group 44 will form a part of the first circulation flow, and the first circulation flow is stabilized. The amount of cooling water supplied from the upper cooling water pipe group 44 is preferably 700m 3 / h and above and 3000m 3 If the cooling water volume supplied from the upper cooling water pipe group 44 is less than 700m 3 / h, the first circulation flow may not be stabilized, which is undesirable. In addition, if the amount of cooling water supplied from the upper cooling water pipe group 44 exceeds 3000m 3 / h, the effect of stabilizing the first circulation flow is saturated, and the granular iron 66 does not contribute to cooling, but only flows down along the inclined surface 34 and is discharged from the drain port 22 at the lower end of the partition cylinder 32, which is undesirable. In addition, the distribution of the cooling water supplied from the slit 42 and the water supply port 43 is preferably 6:4.

[0056] As the lower cooling water pipe group 48, it is preferred that at least one group of water pipes be horizontally connected to the side of the pipe barrel 35 and facing the tube center of the pipe barrel 35. When cooling water 24 is supplied to the pipe barrel 35 from the lower cooling water pipe group 48, the cooling water 24 flows to the tube center of the pipe barrel 35, merges at the tube center and rises, generating a second circulation flow circulating in the pipe barrel 35.

[0057] The amount of cooling water supplied from the lower cooling water pipe group 48 is preferably 250 m 3 / h and above and 750m 3 If the cooling water volume supplied from the lower cooling water pipe group 48 is less than 250m 3 / h, it is not easy to generate the second circulation flow in the pipe cylinder 35, and a stagnant area with high water temperature may be generated, which is not desirable. In addition, if the cooling water supply from the lower cooling water pipe group 48 exceeds 750m 3 / h, it will hinder the drainage from the lower end of the partition cylinder 32, which is not desirable.

[0058] The flow rate of the cooling water 24 supplied from the lower cooling water pipe group 48 is preferably 0.5 m / s or more and 1.0 m / s or less. If the flow rate of the cooling water 24 supplied to the pipe cylinder 35 is slower than 0.5 m / s, the effect of stirring the pipe cylinder 35 is reduced, which is not desirable. In addition, if the flow rate of the cooling water 24 supplied to the pipe cylinder 35 is faster than 1.0 m / s, water leakage from the gap between the lower end of the pipe cylinder 35 and the conveying device 50 increases, which is not desirable.

[0059] Figure 2 It is a cross-sectional schematic diagram of the water flow control container 30 connected to the cooling water pipe group. Figure 2 (a) is a cross-sectional schematic diagram of the water flow control container 30 connected to the upper cooling water pipe group 44. Figure 2 (b) is a cross-sectional schematic diagram of the water flow control container 30 connected to the middle cooling water pipe group 46. Figure 2 (c) is a schematic cross-sectional view of the water flow control container 30 connected to the lower cooling water pipe group 48.

[0060] like Figure 2As shown in (a), the upper cooling water pipe group 44 is composed of two cooling water pipes 41. The cooling water 24 is supplied from the two cooling water pipes 41 to the water supply jacket 45, and is distributed from the water supply jacket 45 to the annular gap 42 and 16 water supply ports 43 radially arranged on the inclined surface 34 of the partition cylinder 32. The cooling water 24 is supplied to the partition cylinder 32 from the annular gap 42 and the 16 water supply ports 43. The middle cooling water pipe group 46 is composed of four cooling water pipes 41 horizontally arranged toward the center of the partition cylinder 32. The cooling water 24 is supplied to the partition cylinder 32 from the four cooling water pipes 41. The lower cooling water pipe group 48 is composed of four cooling water pipes 41. Two of the four cooling water pipes 41 are horizontally arranged opposite to the center of the pipe cylinder 35, and the other two cooling water pipes 41 are arranged on the side of the pipe cylinder. The cooling water 24 is supplied from the four cooling water pipes 41 to the pipe cylinder 35. Thus, in the granular iron manufacturing apparatus 70 of the present embodiment, the cooling water is supplied to the partition cylinder 32 and the pipe cylinder 35 from a total of ten cooling water pipes 41. Figure 2 In the example shown, the cross-sectional shape of the duct cylinder 35 is a quadrilateral, but the present invention is not limited thereto, and the cross-sectional shape of the duct cylinder 35 may also be a circle.

[0061] Figure 3 It is a cross-sectional schematic diagram illustrating the circulating flow generated in the partition cylinder 32 and the pipe cylinder 35. The first circulating flow B1 is the circulating flow that circulates in the partition cylinder 32. The cooling water 24 supplied from the middle cooling water pipe group 46 converges at the center of the cylinder to form a strong upward flow. The strong upward flow expands toward the peripheral portion near the inlet 33. The water flow that expands to the peripheral portion becomes a downward flow that descends along the inclined surface 34. The downward flow merges with the cooling water flow from the gap 42 and the water supply port 43, and through the rectifying effect of these cooling water flows, it flows downward along the inclined surface 34 and is discharged from the lower end connected to the pipe cylinder 35. Through the first circulating flow B1 in the partition cylinder 32, the water temperature of the area from the middle section to the upper section in the cooling area A can be maintained at a suitable water temperature of around 50°C. Furthermore, since the strong upward flow generated in the core portion of the partition cylinder 32 becomes a counterflow to the granular iron 66 introduced from the introduction port 33 and descending, the granular iron 66 can be cooled with high cooling efficiency.

[0062] The second circulation flow B2 is a circulation flow generated in the pipe cylinder 35. The drainage from the lower end of the partition cylinder 32 merges with the low-temperature jet flow from the lower cooling water pipe group 48 and is stirred, thereby generating a circulation flow in the pipe cylinder 35. Thus, the granular iron collected by the partition cylinder 32 can be efficiently cooled.

[0063] In this way, by generating the first circulation flow B1 in the partition cylinder 32 and the second circulation flow B2 in the pipe cylinder 35, the cooling water in the partition cylinder 32 and the pipe cylinder 35 can be stirred, and the generation of stagnant areas in the partition cylinder 32 and the pipe cylinder 35 can be suppressed. As a result, the local temperature rise of the cooling water 24 in the partition cylinder 32 and the pipe cylinder 35 can be suppressed, and the granular iron 66 can be efficiently cooled. As a result, it is suppressed that the granular iron 66 is not sufficiently cooled and the granular irons are fused and combined with each other.

[0064] The upward flow generated in the center of the partition cylinder 32 becomes a cooling water flow opposite to the granular iron 66 dropped from the inlet 33, so that a high cooling efficiency can be obtained. In order to appropriately form this upward flow, the total amount of cooling water supplied from the middle cooling water pipe group 46 is preferably greater than the total amount of cooling water supplied from the upper cooling water pipe group 44.

[0065] In addition, the cooling water flow supplied from the upper cooling water pipe group 44 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 ejection flow from the middle cooling water pipe group 46 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 cooling water pipe group 44 is greater than the amount of cooling water supplied from the middle cooling water pipe group 46, the water flow ejected from the middle cooling water pipe group 46 will be weakened by the water flow of the cooling water, and there is a concern that it is not easy to form the first circulation flow B1. Therefore, the total amount of cooling water supplied from the middle cooling water pipe group 46 is preferably greater than the total amount of cooling water supplied from the upper cooling water pipe group 44. Moreover, the total amount of cooling water supplied from the middle cooling water pipe group 46 is more preferably about 4 times the total amount of cooling water supplied from the upper cooling water pipe group 44.

[0066] The total amount of cooling water supplied from the lower cooling water pipe group 48 connected to the pipe cylinder 35 is preferably less than the total amount of cooling water supplied from the upper cooling water pipe group 44. If the total amount of cooling water supplied from the lower cooling water pipe group 48 is greater than the total amount of cooling water supplied from the upper cooling water pipe group 44, drainage from the lower end of the partition cylinder 32 to the pipe cylinder 35 will be hindered, and there is a concern that the temperature inside the partition cylinder 32 will rise instead. Therefore, the total amount of cooling water supplied from the lower cooling water pipe group 48 is preferably less than the total amount of cooling water supplied from the upper cooling water pipe group 44. Moreover, the total amount of cooling water supplied from the lower cooling water pipe group 48 is more preferably about 1 / 2 of the total amount of cooling water supplied from the upper cooling water pipe group 44.

[0067] In order to appropriately generate the first circulation flow B1 and suppress the temperature rise in 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 cooling water pipe group 46, the upper cooling water pipe group 44, and the lower cooling water pipe group 48. Since it is preferable to control the total amount of cooling water supplied from each cooling water pipe group as described above, the granular iron manufacturing device 70 of this embodiment preferably further includes a control device for controlling the total amount of cooling water supplied from the upper cooling water pipe group 44, the middle cooling water pipe group 46, and the lower cooling water pipe group 48. The control device is composed of a general-purpose computer, and controls cooling equipment such as a heat exchanger and a cooling tower (not shown) to control the supply water amount of the cooling water 24 sent to each cooling water pipe group.

[0068] In addition, the granular iron 66 cooled in the water flow control container 30 is discharged from the discharge port 36 provided at the lower part of the water flow control container 30. The discharged granular iron 66 is transported to the outside of the cooling water tank 20 by a conveying device 50 such as a belt conveyor. The conveying device 50 is not limited to a belt conveyor, and may be other conveying devices as long as it can transport the granular iron 66 to the outside of the cooling water tank 20. However, it is preferable to use a net conveyor as the conveying device 50 to prevent the cooling water 24 from being transported to the outside of the cooling water tank 20.

[0069] Figure 4 FIG. 2 is a schematic cross-sectional view showing another water flow control container 80 used in the granular iron production apparatus of the present embodiment. Figure 4 In the water flow control container 80 shown, Figure 1 The same structures of the water flow control container 30 are marked with the same reference numerals, and their description is omitted. Figure 4 The water flow control container 80 shown is different from the water flow control container 80 in that it has a protrusion 90. Figure 1 The water flow control container 30 shown is different.

[0070] If a water supply port 43 for supplying cooling water 24 is provided on the inclined surface 34 of the partition cylinder 32, there is a concern that the granular iron 66 falling along the inclined surface 34 may intrude into the water supply port 43 and block the water supply port 43. Therefore, it is preferable to provide a protrusion 90 covering the upper side of the connection portion of the water supply port 43 and / or the middle cooling water pipe group 46 connected to the inclined surface. Here, covering the upper side of the connection portion of the water supply port 43 and the middle cooling water pipe group 46 means that the protrusion 90 is provided until the position where the connection portion of the water supply port 43 and the middle cooling water pipe group 46 is blocked when viewed from above. In addition, the protrusion 90 is preferably provided to protrude in the horizontal direction from the inclined surface 34 toward the inside of the partition cylinder 32 in a manner that does not hinder the flow of the supplied cooling water 24.

[0071] Figure 5 This is a schematic diagram when the water supply port 43 provided with the protrusion is viewed from the horizontal direction. Figure 5(a) shows an inverted V-shaped protrusion 90, Figure 5 (b) shows an inverted U-shaped protrusion 91. Figure 5 As shown in (a), the cross-sectional shape of the protrusion 90 is preferably an inverted V-shaped shape that protrudes upward and expands downward. By making the cross-sectional shape of the protrusion 90 an inverted V-shaped shape, it is possible to suppress the accumulation of the granular iron 66 on the upper surface of the protrusion 90 while suppressing the intrusion of the granular iron 66 into the water supply port 43.

[0072] The protrusion 91 having an inverted U-shaped cross section may be provided instead of the protrusion 90. By providing the protrusion 91 having an inverted U-shaped cross section, the iron granules 66 can be prevented from being deposited on the upper surface of the protrusion 91 and from entering the water supply port 43.

[0073] Figure 6 FIG. 2 is a schematic cross-sectional view showing another water flow control container 82 used in the granular iron production apparatus of the present embodiment. Figure 6 In the water flow control container 82 shown, Figure 4 The same structures of the water flow control container 80 are denoted by the same reference numerals, and the description thereof is omitted. Figure 6 The water flow control container 82 shown is different from the Figure 4 The water flow control container 80 shown is different.

[0074] As described above, if the water supply port 43 is provided, there is a concern that the granular iron 66 falling along the inclined surface 34 may intrude into the water supply port 43 and block the water supply port 43. In particular, the granular iron 66 in the upper section of the partition cylinder 32 is still in a molten state, so if it condenses on the inner side of the water supply port 43, it is difficult to remove it. 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 position where the water supply port 43 is blocked when viewed from above. In addition, it is preferable to provide the protective cover 92 at a position where the water supply port 43 is not blocked when the water supply port 43 is viewed from the horizontal direction in a manner that does not hinder the flow of the cooling water 24 supplied from the water supply port 43. Moreover, the protective cover 92 also covers the inclined surface 34 above the water supply port 43 along the inclination direction of the inclined surface 34. The upper end of the protective cover 92 is preferably closed to prevent the scattered droplets 64 from entering the protective cover 92 , and the inclination angle of the protective cover 92 is preferably the same as the inclined surface 34 .

[0075] Figure 7 This is a schematic diagram of the water supply port 43 provided with the protective cover 92 when viewed from the horizontal direction. Figure 7As shown, the cross-sectional shape of the protective cover 92 is preferably a semicircular or semi-elliptical shape that expands downward. By making the cross-sectional shape of the protective cover 92 a semicircular or semi-elliptical shape, the granular iron 66 can be prevented from accumulating on the upper surface of the protective cover 92 and from intruding into the water supply port 43.

[0076] It should be noted that, in the water flow control containers 80 and 82, an example is shown in which the protrusion 90 or the protective cover 92 is provided for the water supply port 43, but the present invention is not limited thereto, and the protrusion 90 and the protective cover 92 may also be provided for the water supply port 43. Even with such a structure, the intrusion of the granular iron 66 into the water supply port 43 can be suppressed.

[0077] As described above, in the granulated iron manufacturing apparatus 70 of the present embodiment, the first circulation flow B1 of the cooling water 24 flowing from the bottom to the top is generated in the partition cylinder 32, and the second circulation flow B2 of the cooling water 24 flowing from the bottom to the top is generated in the pipe cylinder 35, and the granulated iron 66 is cooled by these two circulation flows, and the granulated iron 66 is manufactured from the molten iron 60. The first circulation flow B1 is a countercurrent flow with respect to the descending direction of the granulated iron 66, so the granulated iron 66 can be efficiently cooled by the first circulation flow B1. In addition, the inside of the partition cylinder 32 and the pipe cylinder 35 are stirred by the circulation flows B1 and B2, so the generation of stagnant areas in the partition cylinder 32 and the pipe cylinder 35 can be suppressed. As a result, the cooling effect of the granulated iron is improved, and the granulated iron can be suppressed from fusing and combining with each other when the granulated iron is cooled.

[0078] Next, the results of a simulation that confirmed the cooling effect of the granular iron achieved by the granular iron production apparatus of the present embodiment will be described. Figure 1 The cooling water supply model with the same structure as the water flow control container 30 arranged in the cooling water tank 20 is used to simulate the water temperature distribution of the cooling water in and around the water flow control container. It should be noted that the falling speed and heat of the granular iron in the water in the partition cylinder and on the inclined surface are measured by experiments conducted in advance, and the position distribution and heat generation of the granular iron in the partition cylinder and the pipe cylinder are modeled.

[0079] In the simulation results, if the cooling water temperature in the partition cylinder, the pipe cylinder and the surroundings is 70°C or less, and the temperature is cooled to 650°C or less when the granular iron is accumulated on the conveyor, it is determined that the granular iron can be efficiently cooled.

[0080] Figure 8 : is a diagram showing the simulation conditions of Invention Example 1 and Invention Example 2. Fig. 9 The diagram shows the simulation conditions of Comparative Examples 1 and 2. The cooling water supply model of Inventive Example 1, Inventive Example 2, Comparative Example 1 and Comparative Example 2 is set as Figure 8 and Fig. 9The simulation was performed based on the piping layout, number of pipes, flow distribution of cooling water, and pipe diameter (nominal diameter (A)) shown in FIG. Figure 2 The cooling water pipe layout of the water flow control container 30 shown is the same.

[0081] The cooling water pipe layout of Invention Example 2 is the same as that of Invention Example 1, except that the number of cooling water pipes connected to the water supply jacket of the upper cooling water pipe group becomes one, and the number of water pipes connected to the side of the pipe cylinder of the lower cooling water pipe group is one less than that of Invention Example 1. In Invention Example 2, the following model is used: the total cooling water volume supplied from the middle cooling water pipe group is about 40% of that of Invention Example 1, and the water volume of cooling water supplied from the upper cooling water pipe group is three times that of Invention Example 1, and the flow distribution of cooling water is changed.

[0082] In Comparative Example 1, the following model is used: the upper cooling water pipe group and the lower cooling water pipe group are removed, and only the middle cooling water pipe group is used to supply cooling water. The number of pipes, the configuration, the flow rate of cooling water and the pipe diameter of Comparative Example 1 are the same as those of Inventive Example 1. In Comparative Example 2, the following model is used: the number of pipes of the middle cooling water pipe group and the lower cooling water pipe group is less than half of that of Inventive Example 1, the amount of cooling water supplied is halved, the amount of cooling water supplied from the upper cooling water pipe group is twice that of Inventive Example 1, and the flow distribution of cooling water is changed. The two pipes of the middle cooling water pipe group are connected to the inclined surface at a point-symmetrical position relative to the center of the horizontal cross-section of the partition cylinder in such a way that the central axis of each cooling water pipe is parallel.

[0083] Other simulation conditions common to Inventive Example 1, Inventive Example 2, Comparative Example 1, and Comparative Example 2 are as follows.

[0084] (1) Temperature of molten iron: 1500℃

[0085] (2) The flow rate of molten iron from the tundish: 450 ton / h

[0086] (3) Cooling water temperature: 35°C

[0087] (4) Inclined angle of the inclined surface of the partition cylinder: 56°

[0088] (5) Discharge port diameter of the partition cylinder: φ1560mm

[0089] (6) Height of the partition cylinder: 3300mm

[0090] (7) Height of the inclined surface of the partition cylinder: 3291 mm (length of the inclined surface: 3970 mm)

[0091] Fig.10 is a diagram showing the simulation results of Invention Example 1 and Invention Example 2. Fig.10 As shown in Example 1 of the invention, the cooling water temperature in the water flow control container was 52-69°C, achieving the target temperature of 70°C or less. Furthermore, the maximum temperature of the granular iron when deposited on the conveyor was 550°C, also achieving the target temperature of granular iron of 650°C or less.

[0092] Fig.11 This is a schematic perspective view showing the flow of cooling water supplied from each cooling water pipe group in Inventive Example 1. Fig.11 (a) is a perspective schematic diagram showing the flow of cooling water supplied from the upper cooling water pipe group. Fig.11 (b) is a perspective schematic diagram showing the flow of cooling water supplied from the middle cooling water pipe group. Fig.11 (c) is a perspective schematic diagram showing the flow of cooling water supplied from the lower cooling water pipe group. Fig.11 As shown in (a) and (b), it is confirmed that in the invention example, a first circulation flow is generated in the partition cylinder. Fig.11 (c) confirms that in the inventive example, a second circulation flow is generated in the pipe cylinder.

[0093] Refer again Fig.10 In Example 2 of the invention, although the amount of cooling water from the middle cooling water pipe group was reduced to 40%, an upward flow was generated at the center of the cylinder. In addition, a stronger water flow descending from the upper cooling water pipe group along the inclined surface of the partition cylinder was generated especially on the side where the cooling water pipe was connected to the water supply jacket (the right side of the paper), the first circulation flow was stabilized and 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. Moreover, the maximum temperature of the granular iron when it was deposited on the conveying device was 646°C, and the target of the granular iron temperature of below 650°C was also achieved. It should be noted that if the temperature of the granular iron when it was deposited on the conveying device of Example 1 and Example 2 of the invention is compared, the total amount of cooling water supplied from the middle cooling water pipe group is about 100°C lower than that of Example 1 of the invention in which the total amount of cooling water supplied from the upper cooling water pipe group is larger. From this result, it was confirmed that the granular iron can be cooled with higher cooling efficiency by making the total cooling water amount supplied from the middle cooling water tube group larger than the total cooling water amount supplied from the upper cooling water tube group.

[0094] Fig.12 is a diagram showing the simulation results of Comparative Example 1 and Comparative Example 2. Fig.12As shown in FIG. 1 , in Comparative Example 1, since a large amount of cooling water is supplied from the middle cooling water pipe group, a strong upward flow is generated. The cooling water is stirred by the upward flow, and the cooling water temperature in the central part of the partition cylinder is maintained below 70°C. However, the cooling water is not stirred in the upper and lower parts of the partition cylinder, and the cooling water in these areas is stagnant. As a result, the temperature of the granular iron when it is deposited on the conveyor is 652°C, which is slightly higher than the target temperature of 650°C or below.

[0095] In Comparative Example 2, the two pipes of the middle cooling water pipe group are connected to the inclined surface at a point-symmetrical position relative to the center of the horizontal cross-section of the partition cylinder so that the central axis of each cooling water pipe is parallel. Therefore, unlike Inventive Example 1 and Comparative Example 1, a strong upward flow near the cylinder center is not generated, and a swirling flow that swirls and rises in the partition cylinder is generated instead of the upward flow. The water temperature in the partition cylinder of Comparative Example 2 is lower than that of Inventive Example 1 and Comparative Example 1, which means that the heat of the granular iron cannot be taken away. The maximum temperature of the granular iron when it is accumulated on the conveying device is 700°C, which greatly exceeds the target temperature of less than 650°C, and the deviation of the granular iron temperature is as large as 460°C~700°C. The above simulation results confirm that the granular iron manufacturing device of this embodiment can be used to efficiently cool the granular iron.

[0096] Next, we will explain Figure 4 and Figure 6 The water flow control containers 80 and 82 shown are results of checking the presence or absence of intrusion of granular iron into the water supply port 43. Fig.13 : is a figure which shows the result of checking whether the granular iron has entered the water supply port 43. Figure 4 The water flow control container 80 shown in the invention example 4 is Figure 6 A water flow control container 82 is shown.

[0097] In Inventive Example 3, since the protrusion 90 covering the upper side of the water supply port 43 is provided, the protrusion 90 suppresses the intrusion of the granular iron into the water supply port 43. Thus, it was confirmed that the cooling water 24 can be supplied from the water supply port 43 without being blocked by the granular iron, and the granular iron can be cooled with high cooling efficiency using the water flow control container 80 to produce the granular iron.

[0098] In Inventive Example 4, since the protective cover 92 covering the upper side of the water supply port 43 is provided, the protective cover 92 suppresses the intrusion of the granular iron into the water supply port 43. Thus, it was confirmed that the cooling water 24 can be supplied from the water supply port 43 without being blocked by the granular iron, and the granular iron can be cooled with high cooling efficiency using the water flow control container 82 to produce the granular iron.

[0099] Description of Reference Numerals

[0100] 10 Granulation device

[0101] 12 Tundish

[0102] 14 Molten Iron Receiving Plate

[0103] 16 Nozzle

[0104] 18 Support

[0105] 20 cooling water tank

[0106] 22 Drain

[0107] 24 Cooling water

[0108] 30 Water flow control container

[0109] 32 Separator Cylinder

[0110] 33 Input port

[0111] 34 Inclined surface

[0112] 35 Pipeline cylinder

[0113] 36 Exhaust

[0114] 40 Cooling water pipe group

[0115] 41 Cooling water pipe

[0116] 42 Gap

[0117] 43 Water supply port

[0118] 44 Upper cooling water pipe group

[0119] 45 Water supply set

[0120] 46 Middle cooling water pipe group

[0121] 48 Lower cooling water pipe group

[0122] 50 Conveyor

[0123] 60 Hot metal

[0124] 62 Liquid Column

[0125] 64 Droplets

[0126] 66 grains of iron

[0127] 70 Pellet Iron Manufacturing Device

[0128] 80 Water flow control container

[0129] 82 Water flow control container

[0130] 90 protrusion

[0131] 91 Protrusion

[0132] 92 Protective cover.

Claims

1. A granulated iron manufacturing device, comprising a granulating device and a cooling water tank, wherein the granulating device converts molten iron into droplets, and the cooling water tank cools the droplets by causing the droplets to fall into cooling water, wherein: The granular iron manufacturing device comprises a water flow control container and a cooling water pipe group. The water flow control container is arranged in the cooling water tank and has upper and lower ends opened. The cooling water pipe group supplies cooling water into the water flow control container. The water flow control container comprises a partition cylinder and a pipe cylinder, wherein the partition cylinder has an inclined surface inclined in such a manner that the horizontal cross-sectional area becomes narrower toward the bottom, and the pipe cylinder is connected to the bottom of the partition cylinder. The cooling water pipe group comprises an upper cooling water pipe group and a middle cooling water pipe group connected to the partition cylinder and a lower cooling water pipe group connected to the pipeline cylinder. The upper cooling water pipe group is connected to the upper section of the inclined surface including the upper end of the partition cylinder, and the cooling water supplied from the upper cooling water pipe group generates a cooling water flow along the inclined surface from top to bottom. The middle cooling water pipe group is horizontally connected to the middle section of the inclined surface of the partition cylinder toward the center of the partition cylinder, and a first circulation flow is generated by using the cooling water supplied from the middle cooling water pipe group. The first circulation flow goes to the center of the partition cylinder, merges and rises at the center, and circulates in the partition cylinder along with the cooling water flow along the inclined surface from top to bottom. The lower cooling water pipe group is connected to the side surface of the pipe cylinder, and a second circulation flow circulating in the pipe cylinder is generated by using cooling water supplied from the lower cooling water pipe group and drainage from the partition cylinder.

2. The granular iron manufacturing device according to claim 1, The granular iron manufacturing device further comprises a conveying device, which is disposed below the water flow control container and conveys the granular iron cooled in the water flow control container to the outside of the cooling water tank.

3. The granular iron production device according to claim 1 or 2, The granular iron manufacturing device also has a control device for controlling the amount of cooling water supplied from the cooling water pipe group to the water flow control container, and the control device controls in such a manner that the amount of cooling water supplied from the cooling water pipe group decreases in the order of the middle cooling water pipe group, the upper cooling water pipe group, and the lower cooling water pipe group.

4. The granular iron production device according to any one of claims 1 to 3, The granulated iron manufacturing device has a protrusion that covers the upper side of a connection portion where the upper cooling water pipe group is connected to the inclined surface and / or the upper side of a connection portion where the middle cooling water pipe group is connected to the inclined surface.

5. The granular iron manufacturing device according to claim 4, The cross-sectional shape of the protrusion is an inverted V shape or an inverted U shape extending from the upper side to the lower side.

6. The granular iron production device according to any one of claims 1 to 5, The granular iron manufacturing device includes a protective cover that covers the upper side of a connection portion where the upper cooling water pipe group is connected to the inclined surface, and an upper end portion of the protective cover is closed.

7. The granular iron production device according to claim 6, The cross-sectional shape of the protective cover is a semicircle or a semi-ellipse extending from the top to the bottom.

8. A method for producing granular iron using the granular iron production apparatus according to any one of claims 1 to 7, wherein: The amount of cooling water supplied from the cooling water tube groups decreases in the order of the middle cooling water tube group, the upper cooling water tube group, and the lower cooling water tube group.

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