JP2022149432A - Method for detecting throughput of molten iron, method for controlling grained iron production facility and device for detecting throughput of molten iron - Google Patents

Abstract

To provide a method for detecting the throughput of molten iron capable of measuring the throughput of molten iron fed from a tundish to a cooling facility without using a weighing device, a device for detecting the throughput of molten iron and a method for controlling a grained iron production facility using the detection method.SOLUTION: A method for detecting the throughput of molten iron is used for a grained iron production facility in which molten iron stored in a tundish is exhausted from the exhaust hole of the tundish to a cooling device to produce grained iron. Using the liquid face height of the molten iron in the tundish and the inside diameter of the exhaust hole, the throughput of the molten iron is obtained.SELECTED DRAWING: Figure 1

Description

The present invention relates to a method for detecting the amount of hot metal processed in a granular iron manufacturing facility that manufactures granular iron from hot metal, a control method for the granular iron manufacturing facility, and a device for detecting the amount of molten iron processed in the granular iron manufacturing facility.

Hot metal produced in a blast furnace is transported in a molten state to a steelmaking plant, where it is refined. On the other hand, molten pig iron is sometimes solidified into granules and used as an iron source. Patent Literature 1 discloses a granulated pig iron manufacturing facility that manufactures granulated pig iron by supplying molten pig iron conveyed using a molten pig iron carrier facility such as a toped car to a cooling facility via a tundish. The granulated pig iron produced by being cooled in the cooling equipment is transported by a conveyor or the like to a predetermined storage equipment and stored.

Japanese Patent Application Publication No. 2018-512499

In order to stably produce granulated pig-iron with a predetermined particle size in this facility, the amount of hot metal to be supplied to the cooling facility must be kept at a predetermined amount, It is necessary to keep the ratio within a predetermined range and maintain stable contact between the hot metal and the cooling water. Thus, in order to keep the ratio between the amount of hot metal processed and the amount of cooling water used in the cooling equipment within a predetermined range, it is necessary to measure the amount of hot metal processed in some way.

The amount of hot metal to be processed is such that the amount of granulated iron generated and retained in the cooling facility is almost constant, and the granulated iron is extracted and conveyed to the storage facility by a conveyor. A transport amount measuring device such as a conveyor scale is installed on the conveyor that transports the hot metal, and the amount of granulated iron transported is measured, and this value is taken as the amount of hot metal processed. However, this method measures the amount of granulated iron cooled by the cooling equipment, so if the amount of molten iron supplied from the tundish to the cooling equipment changes, the change is detected by the conveying amount measuring instrument. Since it takes about 5 minutes to complete the process, there is a problem that the control of the amount of cooling water in the cooling equipment and the control of the amount of hot metal treated are delayed.

On the other hand, there is also a method of measuring the treated amount of hot metal supplied from the tundish to the cooling equipment by installing a weighing device on the table of the tundish and measuring the weight change of the entire tundish. However, this method has the problem that it is difficult to accurately measure the increase or decrease in the weight of the tundish because measurement errors occur in the weighing device and impurities adhere and grow on the tundish during operation. there were. SUMMARY OF THE INVENTION The present invention has been made in view of such prior art, and provides a method for detecting the amount of hot metal treated, which can measure the amount of treated hot metal supplied from a tundish to a cooling facility without using a weighing device. It is an object of the present invention to provide a detection device and a control method for granulated iron manufacturing equipment using the detection method.

上記（１）式において、Ｘは前記溶銑処理量（ｔ／ｓ）であり、ρは前記溶銑の密度（ｔ／ｍ^３）であり、Ｃは流量係数であり、ｇは重力加速度（ｍ／ｓ^２）であり、Ｈは前記液面高さ（ｍ）であり、πは円周率であり、Ｄは前記内径（ｍ）である。
［３］［２］または［３］に記載の溶銑処理量の検出方法で求められる前記溶銑処理量が予め定められた範囲内になるように前記液面高さを制御する、粒銑製造設備の制御方法。
［４］前記タンディッシュへの前記溶銑の注入流量を制御することで前記液面高さを制御する、［３］に記載の粒銑製造設備の制御方法。
［５］タンディッシュに貯留される溶銑を、前記タンディッシュから冷却装置に排出して粒銑を製造する粒銑製造設備における溶銑処理量の検出装置であって、前記タンディッシュ内の前記溶銑の液面高さを計測する液面計と、前記タンディッシュの排出孔から排出される前記溶銑を撮像して画像データを生成するカメラと、前記カメラから取得した画像データを用いて前記排出孔の内径を求め、前記液面計から取得した液面高さと前記内径とを用いて溶銑処理量を検出する演算装置と、を有する、溶銑処理量の検出装置。
［６］前記演算装置は、下記（１）式を用いて溶銑処理量を検出する、［５］に記載の溶銑処理量の検出装置。

上記（１）式において、Ｘは前記溶銑処理量（ｔ／ｓ）であり、ρは前記溶銑の密度（ｔ／ｍ^３）であり、Ｃは流量係数であり、ｇは重力加速度（ｍ／ｓ^２）であり、Ｈは前記液面高さ（ｍ）であり、πは円周率であり、Ｄは前記内径（ｍ）である。 Means for solving the above problems are as follows.
[1] A method for detecting the amount of hot metal processed in a granulated iron production facility for producing granulated iron by discharging molten iron stored in a tundish from a discharge hole of the tundish to a cooling device, comprising:
A method for detecting the amount of molten iron processed, wherein the amount of molten iron processed is obtained by using the liquid level of the molten iron in the tundish and the inner diameter of the discharge hole.
[2] The method for detecting the amount of hot metal processed according to claim 1, wherein the amount of hot metal processed is obtained using the following formula (1).

In the above formula (1), X is the amount of molten iron processed (t/s), ρ is the density of the molten iron (t/m ³ ), C is the flow coefficient, and g is the acceleration of gravity (m/ s ² ), H is the liquid level (m), π is the circular constant, and D is the inner diameter (m).
[3] A granulated iron manufacturing facility, wherein the liquid level is controlled so that the amount of molten iron processed determined by the method for detecting the amount of molten iron processed according to [2] or [3] is within a predetermined range. control method.
[4] The control method for granular iron manufacturing equipment according to [3], wherein the liquid level is controlled by controlling the injection flow rate of the hot metal into the tundish.
[5] A device for detecting the amount of hot metal processed in a granulated iron manufacturing facility that manufactures granulated iron by discharging molten iron stored in a tundish from the tundish to a cooling device, the device comprising: A liquid level gauge for measuring the height of the liquid level, a camera for capturing an image of the hot metal discharged from the discharge hole of the tundish to generate image data, and the image data obtained from the camera to detect the discharge hole. A detecting device for the amount of hot metal processed, comprising: an arithmetic device that obtains an inner diameter and detects the amount of hot metal processed by using the liquid level height obtained from the liquid level gauge and the inner diameter.
[6] The apparatus for detecting the amount of hot metal processed according to [5], wherein the arithmetic unit detects the amount of hot metal processed using the following equation (1).

In the above formula (1), X is the amount of molten iron processed (t/s), ρ is the density of the molten iron (t/m ³ ), C is the flow coefficient, and g is the acceleration of gravity (m/ s ² ), H is the liquid level (m), π is the circular constant, and D is the inner diameter (m).

By implementing the method for detecting the amount of hot metal processed according to the present invention, the amount of processed hot metal supplied from the tundish to the hot metal cooling device can be measured without using a weighing device. As a result, it is possible to accurately detect changes in the treated hot metal amount supplied to the hot metal cooling equipment, so that it is possible to control the treated hot metal amount and cooling water amount supplied to the hot metal cooling device without delay. By controlling the amount of hot metal treated and the amount of cooling water in this way, the ratio of the amount of hot metal treated and the amount of cooling water in the hot metal cooling device can be maintained within a predetermined range, and grains of iron of a predetermined grain size can be maintained. Stable production is realized.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram showing an example of granulated iron manufacturing equipment 10 including a device for detecting the amount of hot metal processed according to the present embodiment. 2 is a schematic cross-sectional view showing the configuration of the tundish 20. FIG. 4 is a graph showing a concept of tilting speed control of the torpedo car 14. FIG. 4 is a graph showing temporal changes in hot metal throughput, inner diameter, liquid level height, and tilting speed in Example 1. FIG. 4 is a graph showing temporal changes in hot metal throughput, inner diameter, liquid level height, and tilting speed in Example 2. FIG.

Hereinafter, the present invention will be described through embodiments of the invention. FIG. 1 is a schematic diagram showing an example of granulated iron manufacturing equipment 10 including a device for detecting the amount of hot metal processed according to the present embodiment. The granulated pig iron manufacturing facility 10 includes a tundish 20 , a detection device 30 for the amount of hot metal processed (hereinafter referred to as “detection device 30 ”), a cooling facility 40 , and a transfer facility 50 .

The torpedo car 14 has a spindle shape and is a cart on which a pot-shaped container 16 having an opening in the center is mounted. The torpedo car 14 has an electric motor (not shown), and the electric motor can tilt the pot-shaped container 16 in the lateral direction of the truck about the spindle-shaped ends. Molten iron 12 produced in the blast furnace is introduced into a pot-like container 16 of a torpedo car 14 and transported to the granulated iron manufacturing facility 10 . The hot metal in the pot-shaped container 16 is discharged by tilting the pot-shaped container 16 and poured into the tundish 20 . The injection flow rate of the hot metal 12 into the tundish 20 is adjusted by increasing or decreasing the tilting speed of the pot-shaped container 16 . The tilt speed can be increased or decreased by adjusting the voltage applied to the motor.

FIG. 2 is a schematic cross-sectional view of the tundish 20. As shown in FIG. Tundish 20 has steel shell 25 , refractory 26 , nozzle 27 and stopper 24 . The iron shell 25 is a container having a rectangular parallelepiped shape, and a refractory 26 that protects the iron shell 25 from the heat of the hot metal 12 is provided inside. In the bottom surface of the tundish 20, a cylindrical nozzle 27 having a length L and also made of a refractory material is embedded. A discharge hole 22 is formed by a hollow portion of the nozzle 27 , and the molten iron 12 is discharged from the tundish 20 as a molten iron flow through the discharge hole 22 . The molten iron 12 is supplied from the tundish 20 to the cooling equipment 40 by discharging the molten iron 12 .

A stopper 24 is provided vertically above the discharge hole 22 . In the event of any abnormality, the stopper 24 can move vertically downward to partially or completely block the discharge hole 22 to reduce or stop the discharge of the hot metal 12 from the discharge hole 22 .

Again, refer to FIG. The detection device 30 detects the amount of molten iron that is supplied from the tundish 20 to the cooling facility 40 . The detection device 30 has a liquid level gauge 32 , a camera 34 and an arithmetic device 36 . The liquid level gauge 32 is, for example, a microwave liquid level gauge. The liquid level gauge 32 transmits microwaves to the surface of the molten iron and receives echoes of the transmitted microwaves reflected from the surface of the molten iron. The liquid level gauge 32 measures the time it takes to receive the transmitted microwave, thereby measuring the distance from the liquid level gauge 32 to the surface of the hot metal. The liquid level gauge 32 stores the distance from the liquid level gauge 32 to the bottom surface of the tundish 20 in advance, and the liquid level gauge 32 calculates the distance from the liquid level gauge 32 to the hot metal liquid level measured from this distance. By subtracting , the liquid level H of the hot metal 12 is measured. The liquid level gauge 32 outputs the liquid level height H of the hot metal 12 to the computing device 36 .

The camera 34 images the molten iron flow of the molten iron 12 discharged from the discharge hole 22 of the tundish 20 to generate image data. The camera 34 outputs the generated image data to the computing device 36 . The frequency of outputting the liquid level height H from the liquid level gauge 32 and the frequency of outputting the image data from the camera 34 to the arithmetic unit 36 are preferably at least once every 10 seconds. More preferably, the frequency is equal to or more than once. Camera 34 is preferably a color camera that generates color image data. By using a color camera, it becomes easier to identify the boundary between the hot metal 12 and other portions in image data, which will be described later. However, a monochrome camera may be used as long as the boundary between the hot metal 12 and other portions can be identified.

The computing device 36 is a general-purpose computer such as a personal computer having a computing section such as a CPU and a storage section such as a memory. When acquiring the image data from the camera 34, the computing device 36 obtains the inner diameter D of the discharge hole 22 using the image data. Since the luminance value in the image data differs greatly between the molten iron 12 at about 1500° C. and the portion other than the molten iron 12, the calculation device 36 uses a predetermined luminance threshold value stored in the storage unit to determine the brightness in the image data. The boundary between the molten iron 12 at about 1500° C. discharged from the discharge hole 22 and the portion other than the molten iron 12 is specified.

The calculation device 36 calculates the flow thickness of the molten iron flow discharged from the discharge hole 22 by calculating the distance between the boundary between the identified molten iron 12 and the part other than the molten iron 12 . Since the length corresponding to the flow thickness of the hot metal flow is the same as the inner diameter of the discharge hole 22, the computing device 36 can obtain the inner diameter D of the discharge hole 22 by calculating the flow thickness of the hot metal flow. . When the granulated iron manufacturing facility 10 is used for a long period of time, the refractory inside the discharge hole 22 is worn by the molten iron flow, so the inner diameter D of the discharge hole 22 increases. As described above, the arithmetic device 36 measures the inner diameter D of the discharge hole 22 at a predetermined frequency, so even if the inner diameter D changes, the change can be grasped.

上記（１）式において、Ｘは溶銑処理量（ｔ／ｓ）であり、ρは溶銑１２の密度（ｔ／ｍ^３）であり、Ｃは流量係数であり、ｇは重力加速度（ｍ／ｓ^２）であり、Ｈは液面高さ（ｍ）であり、πは円周率であり、Ｄは排出孔２２の内径（ｍ）である。 The calculation device 36 obtains the molten iron processing amount X using the inner diameter D of the discharge hole 22, the liquid level H of the molten iron 12 obtained from the liquid level gauge 32, and the following equation (1).

In the above equation (1), X is the amount of hot metal processed (t/s), ρ is the density of the hot metal 12 (t/m ³ ), C is the flow coefficient, and g is the gravitational acceleration (m/s ² ), H is the liquid level (m), π is the circular constant, and D is the inner diameter of the discharge hole 22 (m).

In the cooling equipment 40, cooling water is always supplied toward the molten iron 12 supplied from the tundish 20, and the molten iron 12 is cooled to produce granulated iron. The granulated pig iron cooled by the cooling equipment 40 is conveyed to a predetermined storage equipment by a conveying equipment 50 such as a belt conveyor, and stored in the equipment. In order to grasp the production amount of granulated pig iron, a conveying amount measuring device such as a conveyor scale may be installed in the middle of the conveying equipment 50 .

As described above, in the detecting device 30 according to the present embodiment, the hot metal processing amount X is obtained from the inner diameter D of the discharge hole 22 and the liquid level H of the tundish 20. The hot metal throughput supplied from 20 to the cooling equipment 40 can be accurately detected. This makes it possible to detect changes in the amount of molten iron supplied to the cooling equipment 40 without delay in measurement. Then, by controlling the molten iron processing amount and the cooling water amount supplied to the cooling equipment 40 based on the detection result, the ratio between the molten iron processing amount and the cooling water amount in the molten iron cooling device is set within a predetermined range. can be maintained, and stable production of granulated pig iron with a predetermined grain size can be realized.

The detection device 30 preferably obtains the liquid level H and image data at a frequency of once or more every 10 seconds, more preferably once or more every second, and obtains the amount of hot metal processed in real time. As a result, it becomes possible to quickly detect changes in the amount of hot metal to be processed that is supplied from the tundish 20 to the cooling equipment 40, and more stable production of grained pig iron having a predetermined grain size can be realized.

上記（２）式において、Ｘは溶銑の処理速度（ｔ／ｓ）であり、ρは溶銑１２の密度（ｔ／ｍ^３）であり、ｖは溶銑１２の排出速度（ｍ／ｓ）であり、Ｓは排出孔２２の断面積（ｍ^２）である。 Next, the formula (1) for calculating the hot metal throughput X will be described. Equation (1) for calculating the hot metal throughput X is derived from Equation (2) below.

In the above equation (2), X is the hot metal processing speed (t/s), ρ is the density of the hot metal 12 (t/m ³ ), and v is the discharge speed of the hot metal 12 (m/s). , S is the cross-sectional area (m ² ) of the discharge hole 22 .

The discharge speed v of the molten iron 12 is obtained using the liquid level H of the molten iron 12 and the following equation (3).

上記（３）式において、ｖは溶銑１２の排出速度（ｍ／ｓ）であり、ｇは重力加速度（ｍ／ｓ^２）であり、Ｈは液面高さ（ｍ）であり、Ｃは流量係数である。上記（３）式は、底面に開孔を有する容器から流体が自由落下する際の流体の排出速度ｖは、液体の密度、粘度等の物性値に影響されず、容器の「液面高さ」のみで求められるというトリチェリの定理から導かれる式である。トリチェリの定理は上記（３）式に示すように密度および粘度の項がない。このため、溶銑に代えて水を用いた実機スケールの実験を行うことで流量係数Ｃを求めることができる。流量係数Ｃとして１．０５～１．２５（中央値１．１６）を用いることができる。

In the above equation (3), v is the discharge speed (m/s) of the hot metal 12, g is the gravitational acceleration (m/s ² ), H is the liquid level (m), and C is the flow rate. is the coefficient. The above equation (3) shows that the discharge speed v of the fluid when the fluid freely falls from a container having an opening in the bottom is not affected by physical properties such as the density and viscosity of the liquid, and the container "liquid level height It is an expression derived from Torricelli's theorem that it can be obtained only by Torricelli's theorem has no terms of density and viscosity as shown in the above equation (3). Therefore, the flow coefficient C can be obtained by conducting an experiment on an actual scale using water instead of hot metal. A flow coefficient C of 1.05 to 1.25 (median 1.16) can be used.

The cross-sectional area S of the discharge hole 22 can be calculated from the inner diameter D of the discharge hole 22 and the following equation (4).

上記（４）式において、Ｓは排出孔２２の断面積（ｍ^２）であり、πは円周率であり、Ｄは排出孔２２の内径（ｍ）である。上記（２）式に上記（３）式および上記（４）式を代入することで溶銑処理量Ｘを算出する（１）式が導かれる。

In the above equation (4), S is the cross-sectional area (m ² ) of the discharge hole 22 , π is the circular constant, and D is the inner diameter (m) of the discharge hole 22 . By substituting the above equations (3) and (4) into the above equation (2), the equation (1) for calculating the hot metal treatment amount X is derived.

Next, a method for adjusting the amount of hot metal to be processed in the granular iron manufacturing facility 10 will be described. As described above, in order to stably produce granulated pig iron having a predetermined grain size in the granulated pig iron manufacturing facility 10, the ratio between the amount of hot metal treated in the cooling facility 40 and the amount of cooling water should be within a predetermined range. There is a need. Since a predetermined amount of cooling water is always supplied to the cooling equipment 40, the range of the amount of molten iron processing corresponding to the amount of cooling water is set in advance as the range of the target amount of molten iron processing. The hot metal treatment amount should be controlled so that the The molten iron throughput is controlled by controlling the liquid level of the tundish 20, for example. As a result, stable production of granulated pig iron having a predetermined grain size can be achieved in the granulated pig iron manufacturing facility 10 . Note that the stopper 24 may be used to control the amount of hot metal to be processed.

For example, when the granulated iron manufacturing facility 10 is used for a long period of time, the inner diameter of the discharge hole 22 increases and the hot metal throughput increases, and when there is a risk of exceeding the upper limit of the range of the target hot metal throughput, the pot of the torpedo car 14 The tilting speed of the shaped vessel 16 may be slowed down to reduce the injection flow rate of the hot metal 12 into the tundish 20 and lower the liquid level in the tundish 20 . As a result, the amount of treated hot metal discharged from the tundish 20 is reduced, and as a result, the amount of treated hot metal can be maintained within the target amount of treated hot metal.

In addition, if the discharge hole 22 is partially clogged for some reason, the amount of hot metal processed decreases, and there is a possibility that the amount of hot metal processed is less than the lower limit of the range of the target amount of hot metal processed, the pot-shaped container 16 of the torpedo car 14 is tilted. The rolling speed is increased to increase the injection flow rate of the hot metal 12 into the tundish 20 and to raise the liquid level in the tundish 20 . As a result, the amount of treated hot metal discharged from the tundish 20 is increased, and as a result, the amount of treated hot metal can be maintained within the target amount of treated hot metal.

Next, the control of the injection flow rate from the torpedo car 14 for maintaining the liquid level in the tundish 20 at the target liquid level height will be described. FIG. 3 is a graph showing the control concept of the tilting speed of the torpedo car 14. As shown in FIG. In FIG. 3, the tilting speed of the torpedo car 14 that maintains the target liquid level H is defined as "tilting speed R".

For example, when the liquid level rises from H to H1 with respect to the target liquid level H, the tilting speed of the torpedo car 14 is changed from R to R1 in order to lower the liquid level to the target liquid level H. to reduce the injection flow rate of the hot metal 12 into the tundish 20 . As a result, the liquid level is lowered from H1 to H. After the liquid level is lowered to H, the tilting speed of the torpedo car 14 is increased from R1 to R.

On the other hand, when the liquid level is lowered from H to H3, the tilting speed of the torpedo car 14 is increased from R to R3 in order to raise the liquid level to the target liquid level H, and the hot metal is supplied to the tundish 20. 12 increase the infusion rate. As a result, the liquid level rises from H3 to H. After the liquid level rises to H, the tilting speed of the torpedo car 14 is reduced from R3 to R.

By controlling the tilting speed of the torpedo car 14 in this manner, the liquid level in the tundish 20 can be maintained at a target level. The control shown in FIG. 3 can be applied to tilting speeds corresponding to various liquid level heights. is maintained within the range of the target hot metal throughput. As a result, the ratio between the amount of hot metal processed and the amount of cooling water in the cooling equipment 40 can be maintained within a predetermined range, and the granulated pig iron manufacturing equipment 10 can stably produce granulated pig iron having a predetermined grain size. .

Next, Example 1 will be described in which detection and control of the amount of hot metal processed when the liquid level of hot metal in the tundish is lowered is confirmed. In Example 1, in both the invention example and the comparative example, granulated pig iron production equipment capable of producing 300 tons of granulated pig iron in about 60 minutes and a topedo car capable of holding 300 tons of hot metal were used to produce granulated pig iron.

When hot metal is injected from a torpedo car into a tundish to produce granulated iron, even if the inner diameter of the discharge hole is constant, the initial stage (at the start of tilting) and the final stage (at the end of tilting) The liquid level in the dish fluctuates greatly. In Example 1, during the period in which the liquid level in the tundish fluctuates greatly, the amount of hot metal processed is detected every 10 seconds using the granular iron production facility 10 according to the present embodiment, and The liquid level was controlled so that the detected hot metal throughput satisfied the target. On the other hand, in the comparative example, the amount of hot metal processed was detected from the amount of granulated iron measured after 5 minutes by a transportation amount measuring device provided in the transportation equipment, and the liquid level was adjusted so that the detected amount of molten iron processed satisfied the target. controlled. In Example 1, the inner diameter of the discharge hole was assumed to be constant in both the invention example and the comparative example.

FIG. 4 is a graph showing temporal changes in hot metal throughput, inner diameter, liquid level, and tilting speed in Example 1. FIG. FIG. 4(a) shows the change over time in the amount of hot metal processed, and FIG. 4(b) shows the change over time in the inner diameter of the discharge hole. Further, FIG. 4(c) shows the time change of the liquid level height, and FIG. 4(d) shows the time change of the tilt speed. In addition, in the comparative example, the result of operation using equipment having the detection device 30 is based only on the measurement result of the conveying amount measuring instrument after 5 minutes in order to confirm the effectiveness of the present invention. The inner diameter and the liquid level height are not used for control.

As shown in FIG. 4, in the comparative example, the amount of hot metal processed is detected from the production amount of granulated iron measured by the conveying amount measuring instrument after 5 minutes. Control is 5 minutes slower than the inventive example. That is, after 10 minutes, the amount of hot metal processed begins to decrease due to the lowering of the liquid level, but the conveying amount measuring device does not detect this decrease in the amount of hot metal processed until 15 minutes after 5 minutes have passed. As a result, the adjustment for increasing the tilting speed of the torpedo car was delayed by 5 minutes, and the liquid surface level dropped. decreased.

On the other hand, in the example of the invention, since a decrease in the amount of hot metal processed can be detected after 10 minutes and 10 seconds, the tilting speed of the torpedo car 14 can be increased and adjusted according to the detection result of the amount of hot metal processed. As a result, in the invention example, the drop in the liquid level was suppressed, and it became possible to produce granular iron near the target amount of hot metal to be processed, and stable production of granular iron was realized.

Next, Example 2 will be described in which detection and control of the amount of hot metal treated when the discharge hole 22 is rapidly worn and the inner diameter of the discharge hole is enlarged will be described. In Example 2 as well, in both the invention example and the comparative example, granulated pig iron manufacturing equipment capable of producing 300 tons of granulated pig iron in about 60 minutes and a topedo car capable of holding 300 tons of hot metal were used to produce granulated pig iron.

In Example 2, assuming that the inner diameter of the discharge hole expanded due to erosion after 20 minutes, in the invention example, the amount of hot metal processed is detected every 10 seconds using the granulated iron production facility 10 according to the present embodiment, and The liquid level was controlled so that the detected hot metal throughput satisfied the target. On the other hand, in the comparative example, the amount of hot metal processed is detected by the amount of granulated iron measured by a conveying amount measuring device installed in the conveying equipment, and the liquid level is controlled so that the detected amount of hot metal processed satisfies the target. did.

FIG. 5 is a graph showing temporal changes in hot metal throughput, inner diameter, liquid level height, and tilting speed in Example 2. FIG. FIG. 5(a) shows the time change of the molten iron throughput, and FIG. 5(b) shows the time change of the inner diameter of the discharge hole. Also, FIG. 5(c) shows the time change of the liquid level height, and FIG. 5(d) shows the time change of the tilt speed. Also in FIG. 5, the amount of hot metal processed and the liquid level in the comparative example are values based on the measurement results of the conveying amount measuring device after 5 minutes.

As shown in FIG. 5, in the comparative example, the amount of molten iron processed is detected from the production amount of granulated iron measured by the conveying amount measuring instrument after 5 minutes. is 5 minutes slower than the invention example. That is, after 20 minutes have elapsed, the amount of hot metal processed begins to increase due to the expansion of the inner diameter of the discharge hole, but the increase in the amount of molten iron processed is not detected until 5 minutes later, 25 minutes later. For this reason, in the comparative example, the adjustment for lowering the tilting speed of the torpedo car was delayed, and the amount of hot metal processed increased so much that it temporarily exceeded the maximum hot metal processing capacity of 500 t/h of the granulated pig iron production facility 10. Therefore, granulated pig iron was stabilized. It was determined that the standard manufacturing could not be realized. Here, the stable production of granulated pig iron means that the stable operation of the conveying equipment 50 and the cooling capacity of the cooling equipment 40 are maintained. If the maximum hot metal processing capacity of 500 t/h is exceeded, the equipment specification capacity of the transfer equipment 50 will be exceeded, so there is a possibility that the transfer equipment 50 will be overloaded and stopped. When the transfer equipment 50 is overloaded and stopped, high-temperature iron granules may accumulate in the transfer equipment 50, making it impossible to continue operation. Furthermore, if the maximum hot metal processing capacity of 500 t/h is exceeded, the upper limit of the cooling capacity of the cooling equipment 40 will also be exceeded, so the cooling water temperature will rise. If the cooling water temperature becomes too high, a steam explosion will occur in the worst case.

On the other hand, in the example of the invention, since a decrease in the amount of hot metal processed can be detected after 20 minutes and 10 seconds, the tilting speed of the torpedo car 14 can be adjusted to decrease according to the detection result of the amount of hot metal processed. As a result, in the invention example, an increase in the amount of hot metal processed was suppressed, and it became possible to produce granular iron in the vicinity of the target amount of molten iron processed, thereby achieving stable production of granular iron.

REFERENCE SIGNS LIST 10 granulated iron manufacturing equipment 12 hot metal 14 topedo car 16 pot-shaped container 20 tundish 22 discharge hole 24 stopper 25 steel shell 26 refractory 27 nozzle 30 detection device 32 liquid level gauge 34 camera 36 arithmetic device 40 cooling equipment 50 transfer equipment

Claims (6)

A method for detecting the amount of hot metal processed in a granulated iron production facility for producing granulated iron by discharging molten iron stored in a tundish from a discharge hole of the tundish to a cooling device, comprising:
A method for detecting the amount of molten iron processed, wherein the amount of molten iron processed is obtained by using the liquid level of the molten iron in the tundish and the inner diameter of the discharge hole. 2. The method for detecting the amount of processed hot metal according to claim 1, wherein the amount of processed hot metal is obtained using the following formula (1).

In the above formula (1), X is the amount of molten iron processed (t/s), ρ is the density of the molten iron (t/m ³ ), C is the flow coefficient, and g is the acceleration of gravity (m/ s ² ), H is the liquid level (m), π is the circular constant, and D is the inner diameter (m). A control method for a granulated iron manufacturing facility, wherein the liquid level is controlled so that the amount of molten iron throughput determined by the method for detecting the amount of molten iron throughput according to claim 1 or claim 2 is within a predetermined range. . 4. The control method for granulated iron manufacturing equipment according to claim 3, wherein the liquid level is controlled by controlling the injection flow rate of the hot metal into the tundish. An apparatus for detecting the amount of hot metal processed in a granulated iron production facility for producing granulated iron by discharging molten iron stored in a tundish from the tundish to a cooling device, comprising:
a liquid level gauge for measuring the liquid level of the hot metal in the tundish;
a camera for capturing an image of the hot metal discharged from the discharge hole of the tundish to generate image data;
an arithmetic device that obtains the inner diameter of the discharge hole using the image data obtained from the camera, and detects the amount of hot metal processed using the liquid level height obtained from the liquid level gauge and the inner diameter. Quantity detection device. 6. The apparatus for detecting the amount of processed hot metal according to claim 5, wherein the arithmetic unit detects the amount of processed hot metal using the following equation (1).

In the above formula (1), X is the amount of molten iron processed (t/s), ρ is the density of the molten iron (t/m ³ ), C is the flow coefficient, and g is the acceleration of gravity (m/ s ² ), H is the liquid level (m), π is the circular constant, and D is the inner diameter (m).

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