Method and device for detecting residual quantity of liquid or melt and method for operating a vertical furnace

Abstract

Provided is a molten material residual amount detection method and device capable of detecting the residual amount of molten material in a vertical furnace at any timing, and an operation method for a vertical furnace using the detection method. The method is for detecting the residual amount of molten material remaining in the bottom of a vertical furnace after the molten material has been discharged from a tapping hole of the vertical furnace, wherein the vertical furnace is configured to produce molten material by blowing an oxygen-containing gas from the lower portion of the vertical furnace to produce a high-temperature reducing gas by combusting carbon, melting and reducing an iron source material charged from the top of the vertical furnace and forming a solid packed structure in the vertical furnace using the high-temperature reducing gas, and discharging the molten material from the tapping hole of the vertical furnace. The residual amount of molten material is detected using the difference between the production rate of molten material from the tapping hole and the discharge rate of molten material calculated using the discharge acceleration, discharge time, and initial discharge rate of molten material.

Description

Technical Field

[0001] This invention relates to a method and apparatus for detecting the residual amount of liquids, a method and apparatus for detecting the residual amount of molten material in a vertical furnace, and an operating method for a vertical furnace. Background Technology

[0002] For example, in a vertical furnace such as a blast furnace, iron ore and coke, which serve as raw materials, are charged into the furnace from the top, and hot air is blown in through tuyeres located at the bottom of the furnace. The coke is burned by the hot air blown in through the tuyeres, generating high-temperature reducing gases. The iron ore is melted and reduced by these high-temperature reducing gases to produce molten iron. The molten iron and the slag produced during the iron-making process (hereafter sometimes referred to as "slag") accumulate at the bottom of the furnace and are discharged from the taphole at a constant cycle.

[0003] In blast furnace operation, controlling the residual amount of molten iron and slag at the bottom of the furnace, as well as the liquid level of the molten material, is crucial for determining the tapping cycle and ensuring stable and economical operation. If the residual amount of molten material increases and the liquid level is too high, fluctuations in the blast pressure may become too large, making it impossible to maintain stable operation. Furthermore, if the liquid level rises to near the tuyeres, tuyeres may become blocked due to slag, potentially rendering the furnace inoperable in the worst-case scenario. Stabilizing the blast furnace due to an unstable liquid level requires measures such as increasing the amount of coke charged from the top or changing the amount of hot air blown into the furnace from the tuyeres, which increases the operating costs of the blast furnace.

[0004] The amount of molten material remaining in the blast furnace can be roughly estimated by the material balance between the amount of molten slag produced and the amount discharged from the taphole. For example, the amount of molten slag produced can be determined based on the amount of charge fed into the furnace top per unit time and its composition concentration. Furthermore, the amount of molten slag discharged from the taphole can be determined by measuring the weight of the torpedo car containing the molten iron and the weight of the slag produced from the slag. By calculating the difference between the amount of molten slag produced and the amount discharged in this way, the amount of molten material remaining in the blast furnace can be estimated.

[0005] However, the above method can only estimate the residual amount of molten material once for each tapping operation. Molten material tapping operations are performed approximately once every 2-3 hours. Therefore, when operations are based on the residual amount of molten material, this indicator is only obtained once every 2-3 hours, thus there is a possibility of delayed response and potentially exacerbating malfunctions. Therefore, being able to obtain the residual amount of molten material at any given time becomes crucial from the perspective of blast furnace malfunction prevention.

[0006] As a technique for obtaining the residual amount and liquid level of molten material, Patent Document 1 discloses the following method: An electrode is installed on the side of the blast furnace, and a voltage is measured by flowing current through the electrode; the liquid level of the molten material is then measured based on the measured voltage. Patent Document 2 discloses the following method: A camera is used to photograph the flow of molten iron and slag discharged from the tap hole; the discharge speed of the molten iron and slag is calculated based on the image; and the residual amount of molten material inside the blast furnace is estimated based on this discharge speed.

[0007] Existing technical documents

[0008] Patent documents

[0009] Patent Document 1: Japanese Patent Application Publication No. 2006-176805

[0010] Patent Document 2: Japanese Patent Application Publication No. 2017-160498

[0011] Non-patent literature

[0012] Non-patent document 1: “Convenient Guide to Iron and Steel Properties”, Ironmaking Compilation (2006), Japan Iron and Steel Association, p. 437 (“Convenient Guide to Iron and Steel Properties”, Ironmaking Compilation (2006), Japan Iron and Steel Association)

[0013] Non-Patent Literature 2: Sugiyama Takashi, 3 others, “Analysis of Liquid Flow in Blast Furnace Drip Zone”, Iron and Steel, No. 15, 1987, pp. 2044-2051 (Sugiyama Takashi, 3 others, “Analysis of Liquid Flow in Blast Furnace Drip Zone”, Iron and Steel)

[0014] Non-Patent Literature 3: Yusuke Kashiwabara, 4 others, “The Influence of Undisappeared Mixed Small Pieces of Coke on the Ventilation of the Lower Part of the Blast Furnace”, Iron and Steel, Vol. 102 (2016), No. 12, pp. 661-668 (Yusuke Kashiwabara, 4 others, “The Influence of Undisappeared Mixed Small Pieces of Coke on the Ventilation of the Lower Part of the Blast Furnace”, Iron and Steel)

[0015] Non-patent document 4: Nouchi Yasuhei, two others, "The influence of the operation and tapping methods on the slag discharge properties of the blast furnace hearth", Iron and Steel, Vol. 92 (2006), No. 12, P269-274 (Nouchi Yasuhei, two others, "The influence of the operation and tapping methods on the slag discharge properties of the blast furnace hearth") Summary of the Invention

[0016] The problem that the invention aims to solve

[0017] However, the methods disclosed in Patent Documents 1 and 2 require the installation of special sensors and cameras, which are used to measure the resistance, potential, or velocity of the tapped slag flow caused by the molten material in the blast furnace, in an environment that generates dust, etc. Therefore, there is a problem that implementing these methods incurs not only initial costs for introducing special sensors and cameras, but also maintenance costs for maintaining and managing these devices. This invention addresses these problems and aims to provide a method and apparatus for detecting the residual amount of molten material in a vertical furnace at any given time without the need for new special sensors or cameras, as well as an operating method for a vertical furnace using this detection method. Furthermore, another objective of this invention is to provide a method and apparatus for detecting the residual amount of liquid in a container that has been formed by filling it with solids, not limited to a vertical furnace, at any given time.

[0018] Methods for solving problems

[0019] The methods used to solve the above problems are as follows.

[0020] [1] A method for detecting the residual amount of liquid, wherein the residual amount of liquid contained in a container having a solid filling structure formed by filling it with solid material, in a state of being immersed in at least a portion of the voids of the solid filling structure, is discharged from a discharge hole provided at the bottom of the container, wherein the residual amount of liquid is detected by the difference between the supply rate of the liquid and the discharge rate of the liquid, the discharge rate of the liquid being calculated using the discharge acceleration of the liquid from the discharge hole, the discharge time, and the initial discharge rate.

[0021] [2] According to the liquid residual amount detection method described in [1], the porosity of the solid filling structure is calculated using the tilt angle of the liquid surface at the end of the discharge of the liquid from the discharge hole, and the liquid surface height of the liquid at the end of the discharge is detected using the calculated porosity and the residual amount of the liquid after the discharge.

[0022] [3] A method for detecting the residual amount of molten material is used in a vertical furnace in which oxygen-containing gas is blown into the lower part of the furnace, high-temperature reducing gas is generated by burning carbon, iron source raw materials loaded from the top of the furnace and forming a solid filling structure in the furnace are melted and reduced by the high-temperature reducing gas to produce molten material, and the molten material is discharged from the tap hole of the furnace. The method detects the residual amount of molten material at the bottom of the furnace after the molten material is discharged, wherein the difference between the production speed of the molten material and the discharge speed of the molten material is used to detect the residual amount of molten material, and the discharge speed of the molten material is calculated using the discharge acceleration of the molten material from the tap hole, the discharge time, and the initial discharge speed.

[0023] [4] According to the residual amount detection method of the molten material described in [3], the porosity of the solid filling structure is calculated by using the inclination angle of the liquid surface of the molten material at the end of the discharge of the molten material from the iron outlet, and the liquid surface height of the molten material at the end of the discharge is detected by using the calculated porosity and the residual amount of the molten material after the discharge.

[0024] [5] An operating method for a vertical furnace, wherein when the liquid level height detected by the residual amount detection method of the melt described in [4] exceeds a predetermined threshold, at least one of the following operations is performed: reducing the manufacturing speed of the melt and increasing the discharge speed of the melt.

[0025] [6] A liquid residual amount detection device for detecting the residual amount of liquid remaining at the bottom of a container after liquid contained in a container having a solid filling structure formed by filling it with solids and being immersed in at least a portion of the voids of the solid filling structure is discharged from a discharge hole provided at the bottom of the container, wherein the device comprises: a supply speed acquisition unit for acquiring the supply speed of the liquid; a discharge speed acquisition unit for acquiring the discharge speed of the liquid using the discharge acceleration, discharge time and initial discharge speed of the liquid from the discharge hole; and a residual amount calculation unit for calculating the residual amount of the liquid using the difference between the supply speed of the liquid and the discharge speed of the liquid.

[0026] [7] The liquid residual amount detection device according to [6] further includes a liquid level calculation unit, which calculates the porosity of the solid filling structure using the tilt angle of the liquid level at the end of the discharge of the liquid from the discharge hole, and uses the calculated porosity and the residual amount of the liquid after discharge to detect the liquid level after discharge.

[0027] [8] A residual amount detection device for molten material is used in a vertical furnace in which oxygen-containing gas is blown into the lower part of the furnace, high-temperature reducing gas is generated by burning carbon, iron source raw material loaded from the top of the furnace and forming a solid filling structure in the furnace is melted and reduced by the high-temperature reducing gas to produce molten material, and the molten material is discharged from the tap hole of the furnace. The device detects the residual amount of molten material remaining at the bottom of the furnace after the molten material is discharged. The device includes: a manufacturing speed acquisition unit for acquiring the manufacturing speed of the molten material; a discharge speed acquisition unit for acquiring the discharge speed of the molten material using the discharge acceleration, discharge time and initial discharge speed of the molten material from the tap hole; and a residual amount calculation unit for calculating the residual amount of the molten material using the difference between the manufacturing speed and the discharge speed of the molten material.

[0028] [9] The residual amount detection device of the molten material according to [8] further includes a liquid level calculation unit, which calculates the porosity of the solid filling structure using the inclination angle of the liquid level of the molten material at the end of the discharge of the molten material from the iron outlet, and uses the calculated porosity and the residual amount of the molten material after the discharge to detect the liquid level of the molten material after the discharge.

[0029] Invention Effects

[0030] The residual amount of molten material detected by the present invention allows for the detection of residual molten material in a vertical furnace at any given time without incurring initial or maintenance costs for specialized sensors and cameras. This enables the implementation of operations based on residual molten material at desired timeframes while minimizing increases in molten iron production costs, thus preventing vertical furnace malfunctions and achieving stable vertical furnace operation compared to conventional methods. Attached Figure Description

[0031] Figure 1 This is a schematic cross-sectional view of the area near the bottom of the blast furnace.

[0032] Figure 2 This is a block diagram of a residual detection device.

[0033] Figure 3 This is a schematic cross-sectional view of the blast furnace near the bottom at the end of the discharge process.

[0034] Figure 4 This is a graph illustrating the results of the embodiment. Detailed Implementation

[0035] The present invention will now be described through embodiments thereof. In this embodiment, a blast furnace is used as a vertical furnace, and the implementation of the method and apparatus for detecting the residual amount of molten material in the blast furnace will be described. However, the method and apparatus for detecting the residual amount of molten material involved in the present invention are not limited to blast furnaces; any vertical furnace in which iron source raw materials and coke are charged into the furnace from the top, oxygen-containing gas is blown into the furnace from the bottom to produce molten material, and the molten material is discharged from the tap hole can be used.

[0036] Figure 1 This is a cross-sectional schematic diagram of the area near the bottom of the blast furnace 20. Iron ore and coke, serving as raw materials, are alternately and layeredly charged into the furnace body 10 from the top of the blast furnace 20. Hot blast, containing oxygen gas, and reducing materials such as pulverized coal are blown in from the tuyeres 12 located at the bottom of the furnace body 10. The carbon contained in the coke and pulverized coal is burned by the hot blast blown in from the tuyeres 12, thereby generating high-temperature reducing gas. The iron ore is melted and reduced by this high-temperature reducing gas to produce molten iron. The high-temperature reducing gas used in the melting and reduction of the iron ore is then discharged from the top of the furnace as top gas. The produced molten iron and the slag generated during the production of molten iron accumulate at the bottom of the furnace and are discharged from the taphole 18 at predetermined intervals. In this embodiment, the molten iron and slag are collectively referred to as melt 16. Iron ore is an example of an iron source raw material.

[0037] A solid filling structure 14, filled with coke loaded from the top of the furnace, is formed at the bottom of the furnace body 10. Molten material 16 accumulated at the bottom of the furnace body 10 fills the gaps in this solid filling structure 14. When molten material 16 is discharged from the tap hole 18, if the discharge rate from the tap hole 18 is faster than the production rate of molten material 16, the amount of molten material 16 remaining at the bottom of the furnace gradually decreases. If the amount of molten material 16 remaining decreases and the liquid level of molten material 16 drops to the same height as the tap hole 18, high-temperature reducing gas begins to be ejected from the furnace. If high-temperature reducing gas begins to be ejected from the tap hole 18, it becomes difficult to discharge molten material 16 from the tap hole 18. Therefore, other tap holes are opened and the tap hole 18 from which high-temperature reducing gas begins to be ejected is closed, thereby allowing molten material 16 to be continuously discharged from the furnace body 10.

[0038] In the residual amount detection method and apparatus of the molten material according to this embodiment, the production rate and discharge rate of the molten material 16 in the blast furnace 20 are calculated. Furthermore, by taking the difference between the calculated production rate and discharge rate of the molten material 16, the residual amount of the molten material 16 at any given time can be detected. Thus, if the residual amount of the molten material 16 at any given time can be detected, the residual amount of the molten material 16 can be detected at a desired timing, and the residual amount of the molten material 16 can also be detected continuously.

[0039] exist Figure 2 The structure of the residual melt detection device 30 according to this embodiment is shown. Figure 2 As shown, the residual amount detection device 30 includes a manufacturing speed acquisition unit 31 for acquiring the manufacturing speed of the molten material 16, a discharge speed acquisition unit 32 for acquiring the discharge speed of the molten material 16, and a residual amount calculation unit 33 for calculating the residual amount of the molten material 16. Additionally, the residual amount detection device 30 also includes a liquid level calculation unit 34 for detecting the liquid level of the molten material 16 after discharge. These manufacturing speed acquisition unit 31, discharge speed acquisition unit 32, residual amount calculation unit 33, and liquid level calculation unit 34 are configured by a general-purpose computer including a CPU (central processing unit) for processing information and a storage device, and perform the calculations described later. The residual amount detection device 30 also includes a database 35 pre-stored various values ​​used in the calculations described later.

[0040] First, the method for obtaining the manufacturing speed of the melt 16 by the manufacturing speed acquisition unit 31 of the melt residue detection device 30 will be explained. The manufacturing speed PV of the melt 16 is determined based on the air volume and composition concentration of the hot air blown in from the tuyeres 12, the amount and composition of the raw materials charged from the furnace top, and the discharge volume and composition concentration of the furnace top gas discharged from the furnace top. Specifically, the manufacturing speed PV of the melt 16 is calculated by the following formula (1).

[0041] [Number 1]

[0042]

[0043] In equation (1) above, PV is the melting rate (kg / sec). TV is the flow rate of the gas at the furnace top (Nm³). 3 / sec). F O It is the mass concentration of O atoms in the gas at the furnace top (mol / Nm³). 3 BV is the flow rate (Nm) of the hot air blown in from all the vents 12. 3 / sec). E O M is the volume fraction of oxygen in the hot air (-). OM(-) is the ratio of the number of oxygen atoms per mol of the target substance in the raw material to the number of metal atoms. M It is the atomic weight of the metal atom (g / mol). It should be noted that (-) means dimensionless.

[0044] The flow rate TV of the gas at the furnace top is calculated by the following formula (2).

[0045] TV = BV × E N / F N …(2)

[0046] In equation (2) above, TV is the flow rate of the gas at the furnace top (Nm³). 3 / sec). BV is the flow rate of hot air blown in from vent 12 (Nm³). 3 / sec). E N This is the volume fraction of nitrogen in the hot air (-). F N It is the volume fraction of nitrogen in the gas at the furnace top (-).

[0047] Mass concentration F of O atoms in the gas at the furnace top O and the volume fraction of nitrogen F N The flow rate BV of the hot air blown in from all the tuyeres 12 is determined by analyzing the gas at the top of the furnace using a gas analyzer 41 via gas chromatography and infrared spectroscopy.

[0048] The volume fraction of oxygen in hot air, E O The volume fraction of nitrogen E in the hot air can be calculated using the following equation (3). N It can be calculated using the following formula (4).

[0049] E O =(X×0.21+Y) / (X+Y)…(3)

[0050] E N =(X×0.79) / (X+Y)…(4)

[0051] In equations (3) and (4) above, X is the air inlet flow rate (Nm³). 3 / sec). Y is the oxygen blowing flow rate (Nm³). 3 / sec).

[0052] Alternatively, the humidity in the air can be considered, along with the volume fraction of oxygen E in the hot air. O and the volume fraction of nitrogen E in hot air N The following equations (5) and (6) are used to calculate it.

[0053] E O =(X×0.21+Y) / [X+Y+X×(Z / 18)×22.4]…(5)

[0054] E N =(X×0.79) / [X+Y+X×(Z / 18)×22.4]…(6)

[0055] In equations (5) and (6) above, X is the air inlet flow rate (Nm³). 3 / sec). Y is the oxygen blowing flow rate (Nm³). 3 / sec). Z is the moisture content of the air (kg / m³). 3The humidity Z in the air is determined by measuring the air using a hygrometer 43.

[0056] The ratio OM, which is the number of oxygen atoms per mol of the target substance in the raw material relative to the number of metal atoms, is determined by chemical analysis to measure the concentration of the raw material and then calculating the ratio OM based on that concentration.

[0057] The molten material 16 is composed of a mixture of molten metal and slag. Therefore, it is preferable to add the slag production rate to the production rate PV of the molten material 16 calculated by equation (1) above. In this case, the production rate of the molten oxide can be obtained by calculating the mass ratio of the molten oxide to the molten metal based on the composition concentration of the raw materials and multiplying this mass ratio by the production rate of the molten metal.

[0058] Next, the method for obtaining the discharge speed of the molten material 16 by the discharge speed acquisition unit 32 of the molten material residue detection device 30 will be explained. The discharge port of the tap hole 18 is gradually worn away by the molten material 16, and therefore, the discharge port diameter widens over time. As a result, the discharge speed of the molten material 16 gradually increases. The discharge speed increases linearly with respect to time, so the discharge speed v of the molten material 16 is calculated by the following equation (7).

[0059] [Number 2]

[0060] V=V0+a×t…(7)

[0061] In equation (7) above, v is the discharge velocity (m) of the melt 16. 3 / sec). v0 is the initial discharge velocity of melt 16 (m). 3 / sec). t is the discharge time (sec). a is the discharge acceleration (m). 3 / sec 2 Thus, in this embodiment, the discharge velocity v of the melt 16 is calculated using the discharge acceleration a of the melt 16, the discharge time t, and the initial discharge velocity v0.

[0062] In addition, the discharge amount V of the melt 16 discharged at discharge time T is calculated by the following formula (8).

[0063] [Number 3]

[0064]

[0065] In equation (8) above, V is the discharge rate of melt 16 (m³). 3 T is the discharge time (sec). a is the discharge acceleration (m). 3 / sec 2 v0 is the initial discharge velocity (m).3 / sec).

[0066] Next, the method for calculating the initial discharge velocity v0 in equation (8) above will be explained. According to Bernoulli's law, the pressure loss calculated based on the difference between the energy of the molten material 16 near the tap hole and the energy of the discharged molten material 16, and the pressure loss inside the tap hole calculated according to the Darcy-Weisbach formula, are obtained respectively. Assuming that these pressure losses are equal, the following equation (9) is derived.

[0067] [Number 4]

[0068]

[0069] In equation (9) above, P i-Ο ρ is the pressure difference (atm) between the furnace pressure and atmospheric pressure in the vertical furnace. ρ is the density (kg / m³) of the molten material. 3 g is the acceleration due to gravity (9.8 m / sec). 2 Z S It is the difference (m) between the height of the molten material 16 at the start of discharge and the height at the outlet side of the tap hole 18. th λ is the diameter (m) of the tap hole 18. λ is the coefficient of friction (-) of the inner wall of the tap hole 18. th This is the depth of the tap hole (m). The tap hole depth is the length (m) of refractory material that the molten material 16 passes through when it exits the tap hole 18. v0 is the initial discharge velocity (m). 3 / sec).

[0070] The friction coefficient λ of the inner wall of the iron outlet hole 18 is obtained by the Swamee-Jain formula and by the following equation (10).

[0071] [Number 5]

[0072]

[0073] In equation (10) above, λ is the coefficient of friction (-) of the inner wall of the tap hole 18. e is the roughness (m) of the inner wall of the tap hole. d th ρ is the diameter (m) of the tap hole 18. ρ is the density (kg / m³) of the molten material 16. 3 v0 is the initial discharge velocity (m). 3 / sec). S dh 1 is the cross-sectional area of ​​the tap hole 18. μ is the viscosity (Pa·s) of the molten material 16.

[0074] The internal pressure of the vertical furnace is determined by a pressure gauge 44 installed inside the tuyeres 12. Atmospheric pressure can be a general value. The density ρ and viscosity μ of the molten material 16 are the density and viscosity of the molten iron and slag, but in this embodiment, the density and viscosity of slag with high viscosity and a large impact on pressure loss are used. The density ρ of the molten material 16 can be a constant value (a past performance value). Alternatively, the density of the molten material 16 can be calculated using the weight ratio of FeO in the molten slag, as described in Non-Patent Document 1. Furthermore, when estimating the viscosity of the molten material using the method described in Non-Patent Document 1, the temperature of the molten material can be a value obtained by measuring the temperature of the discharged molten material using a thermometer 45 such as a thermocouple.

[0075] The height of the molten material 16 at the start of discharge is determined by substituting the initial residual amount V0 into equation (13) described later. The height of the outlet side of the tap hole 18 is determined by measuring the position of the tap hole 18. The tap hole 18 is drilled using a drill bit, therefore the diameter d of the tap hole 18 is... th This can be determined by measuring the diameter of the drill bit. Additionally, the depth L of the iron-extracting hole... th The result is obtained by measuring the penetration length of the drill bit when the iron hole 18 is opened.

[0076] The roughness e of the inner wall of the tapping hole varies depending on the drilling method, the clay material, and the time elapsed since tapping, but based on operational analysis, a value in the range of 0.0001 to 0.01 μm has been deemed appropriate. The viscosity μ of the molten material 16 can be a constant value (0.25 to 0.35 Pa·s). The viscosity μ of the molten material 16 can also be estimated using the method described in Non-Patent Document 2, which estimates the viscosity based on the concentrations of components such as CaO, MgO, Al2O3, SiO2, and FeO, and the temperature. The cross-sectional area S of the tapping hole 18... dh Use the diameter d of the iron tapping hole 18 th The following equation (11) is used to obtain the result.

[0077] S dh =(d th / 2) 2 ×π…(11)

[0078] By solving equations (9) and (10) above, the initial discharge velocity v0 of the melt 16 can be obtained. The discharge acceleration a can be obtained using v0, the measured value of the discharge volume V of the melt 16 measured by the discharge volume measuring device 46, the measured value of the discharge time T of the melt 16 measured by the discharge time measuring device 47, and equation (8) above. If the initial discharge velocity v0 and the discharge acceleration a can be obtained, the discharge velocity v of the melt 16 can be continuously calculated using equation (7) above.

[0079] Based on the difference between the manufacturing speed PV and the discharge speed v of the melt 16 calculated in this way, the residual amount of melt 16 accumulated at the bottom of the furnace body 10 can be continuously detected. Specifically, the residual amount calculation unit 33 of the melt residual amount detection device 30 uses the following formula (12) to detect the residual amount of melt 16 at any time t (sec).

[0080] [Number 6]

[0081] V=V0+∫(PV(t)-v(t)×ρ)dt…(12)

[0082] In equation (12) above, V is the residual amount of melt 16 (kg). V0 is the initial residual amount of melt 16 (kg). PV is the manufacturing rate of melt 16 (kg / sec). v is the discharge rate of melt 16 (m). 3 / sec). ρ is the density of melt 16 (kg / m³). 3 The initial residual amount V0 is a constant value set according to the capacity of the furnace body 10. The molten material 16 in the blast furnace is generally considered to be pushed upward from the tap hole by 1-2m. Therefore, the initial residual amount V0 is set according to the capacity of the furnace body 10 so that the height of the molten material 16 is 1-2m above the tap hole. By using the above formula (12), the residual amount V of the molten material 16 at any time can be detected. Therefore, the residual amount of the molten material 16 in the vertical furnace can be detected at the desired timing, and the residual amount of the molten material 16 in the vertical furnace can also be detected continuously.

[0083] By using the residual amount detection method and apparatus of the present embodiment, the residual amount of molten material 16 in a vertical furnace can be detected at any time interval. Therefore, operations based on the residual amount of molten material 16 can be performed at a desired time interval, thus better preventing blast furnace operation failures compared to conventional operations performed at intervals of 2 to 3 hours. Furthermore, the residual amount detection method and apparatus of the present embodiment can detect the residual amount of molten material 16 without using special sensors or cameras. This avoids the initial and maintenance costs of introducing special sensors or cameras, and also helps to suppress increases in the cost of molten iron production.

[0084] The above example shows an example of continuously detecting the production rate PV of the molten material 16 using formula (1), but it is not limited thereto. For example, the production rate PV of the molten material 16 can also be calculated based on the charging speed of the raw material charged from the furnace top and the composition concentration of the raw material, and the production rate PV can also be calculated based on the amount of reducing material used to produce a unit weight of molten iron, the composition of the furnace top gas, the amount and composition of the blast gas, and the oxidation degree of the raw material.

[0085] Next, the method for detecting the liquid level of the melt 16 by the liquid level calculation unit 34 of the melt residue detection device 30 will be described. The liquid level of the melt 16 is calculated using the following formula (13).

[0086] [Number 7]

[0087]

[0088] In equation (13) above, Z is the liquid level height of melt 16 (m). V is the amount of melt 16 (kg). ρ is the density of melt 16 (kg / m³). 3 S is the cross-sectional area of ​​the furnace bed (m²). 2 ). ε ave The average porosity (-) of the solid-filled structure 14 is given. The hearth cross-sectional area S is calculated based on the bottom diameter of the vertical furnace. The average porosity ε is used as the reference value. ave When calculating the liquid level height for the first time, the initial value of the porosity ε, 0.4, can be used. After that, the porosity calculated by the following formula (14) and the arithmetic mean of the porosity over the past 10 days can also be used.

[0089] Figure 3 This is a schematic cross-sectional view of the area near the bottom of blast furnace 20 at the end of the discharge process. (Example) Figure 3 As shown, due to the resistance to flow caused by the solid filling structure 14 and the viscosity of the molten material 16, a pressure difference is generated on the upstream and downstream sides of the molten material stream, causing it to tilt towards the tap hole 18 due to this pressure difference. At this time, the height difference Z between the height of the tap hole 18 and the height Z of the molten material 16 at the end of tapping is... f Furnace bed diameter D h The following equation (14) holds true for the tilt angle θ of the liquid surface of the melt 16.

[0090] [Number 8]

[0091]

[0092] In the above equation (14), Z f It is the height difference (m) between the tap hole 18 and the liquid level Z of the molten material 16 at the end of discharge. k is an experimentally determined dimensionless arbitrary constant (-). The dimensionless arbitrary constant k is determined by the method described in Non-Patent Document 4. For example, in the case of a typical blast furnace, k = 7.0. D h ρ is the furnace bed diameter (m). μ is the viscosity of melt 16 (Pa·s). ρ is the density of melt 16 (kg / m³). 3 g is the acceleration due to gravity (9.8 m / s²). 2 ). d pε is the particle size (m) of the solid-filled structure 14. ε is the porosity (-) of the solid-filled structure 14. f It is the discharge velocity (m) of the melt 16 at the end of the discharge process. 3 / sec). S is the cross-sectional area of ​​the furnace bed (m²). 2 ).

[0093] The particle size d of solid-filled structure 14 p When coke is charged from the top of a vertical furnace, the average particle size of the coke charged from the top can be used. Alternatively, as described in Non-Patent Document 3, a value can be used that takes into account the initial particle size distribution of the coke charged from the top of the furnace and the changes in particle size distribution due to chemical reactions, physical impacts, etc., before the coke descends to the bottom of the furnace. The discharge rate v of the molten material 16 at the end of discharge... f The above equation (7) is used to obtain the result.

[0094] The liquid level of melt 16 at the end of the first discharge is determined using the residual amount of melt 16 and the porosity ε. ave The initial value of 0.4 is calculated using the above formula (13). The height difference Z at the end of the first discharge is calculated based on the liquid level and the height of the iron outlet 18. f That is, the tilt angle θ. By using the tilt angle θ and the above equation (14), the void ratio ε at the end of the first discharge can be calculated.

[0095] Thus, in this embodiment, the inclination angle of the molten surface is calculated based on the amount of molten material remaining at the end of molten material discharge, and the porosity ε of the solid filling structure near the furnace inner side of the discharge section is calculated based on this inclination angle. Then, this porosity ε can be used to calculate the molten material 16 height after discharge. As a result, the porosity is updated to reflect the latest furnace conditions, thus improving the detection accuracy of the molten material 16 height calculated using this porosity.

[0096] If the residual amount of molten material 16 detected using formula (12) above, or the liquid level height of molten material 16 detected using formula (13) above, exceeds a predetermined threshold, it is preferable to perform an operation that reduces the production speed of molten material 16. This prevents the liquid level height of molten material 16 from becoming excessively high, thus avoiding deterioration of gas permeability and tuyer blockage caused by slag. Reducing the production speed of molten material 16 can be achieved, for example, by reducing the amount of hot air blown in from tuyer 12. Alternatively, instead of reducing the production speed of molten material 16, an operation that increases the discharge speed of molten material 16 can be performed in conjunction with the operation that reduces the production speed of molten material 16.

[0097] Furthermore, by partially modifying the aforementioned method and apparatus for detecting the residual amount of molten material, it is not limited to blast furnaces or vertical furnaces, but can detect the residual amount of liquid contained in all containers that have formed a solid filling structure inside. That is, it can detect the residual amount of liquid remaining at the bottom of the container after liquid contained in the container in a state of being immersed in at least a portion of the voids of the solid filling structure has been discharged from the discharge hole provided at the bottom of the container.

[0098] Specifically, the liquid residue detection device 30 according to this embodiment is similar to the melt residue detection device 30 described above, including a supply speed acquisition unit 31 for acquiring the liquid supply speed, a discharge speed acquisition unit 32 for acquiring the liquid discharge speed, and a residue calculation unit 33 for calculating the liquid residue. In addition, the liquid residue detection device 30 also includes a liquid level calculation unit 34 for detecting the liquid level after discharge.

[0099] Furthermore, the supply speed acquisition unit 31 acquires the liquid supply speed using the same method as the manufacturing speed acquisition unit 31 of the molten residue detection device 30 described above. Similarly, the discharge speed acquisition unit 32 acquires the liquid discharge speed using the same method as the discharge speed acquisition unit 32 of the molten residue detection device 30 described above. Moreover, the residual amount calculation unit 33 calculates the residual amount of liquid using the difference between the calculated liquid supply speed and the liquid discharge speed, using the same method as the residual amount calculation unit 33 of the molten residue detection device 30 described above. In addition, the liquid level calculation unit 34 calculates the porosity of the solid filling structure using the inclination angle of the liquid level at the end of the discharge from the discharge hole, using the same method as the liquid level calculation unit 34 of the molten residue detection device 30 described above. Finally, the liquid level height of the liquid after discharge is detected using the calculated porosity and the residual amount of liquid after discharge.

[0100] The liquid residue detection method and device involved in this embodiment are not limited to blast furnace processes, but can be applied to all processes in which a container with a solid filling structure is formed inside is contained in a state of immersion into at least a portion of the voids of the solid filling structure.

[0101] Example

[0102] Next, an embodiment will be described. In this embodiment, equations (1) and (7) above were derived using various operating conditions and measured values ​​during blast furnace operation, and equation (12) above was derived based on them. Then, using equation (12), the residual amount of molten material during the blast furnace operation was detected every minute. Moreover, using equation (13), the liquid level height of the molten material was detected every minute based on the detected residual amount of molten material, and using equation (14) above, the average porosity ε of the solid packing structure used in equation (13) was calculated at the end of each discharge. ave .

[0103] The residual amount of the above-mentioned molten material was detected, and the ventilation resistance index K in blast furnace operation was calculated. The ventilation resistance index K is a general index used to evaluate the ventilation performance of a vertical furnace, and is calculated by the following equation (15).

[0104] [Number 9]

[0105]

[0106] In the above equation (15), P b This is the air supply pressure (atm) of the hot air blown in from the vent. P t This is the exhaust pressure of the gas at the furnace top (atm). BV is the air volume of hot air supplied from the tuyeres (Nm³). 3 / sec).

[0107] Ventilation drag index ratio K r The average ventilation resistance index of the vertical furnace being considered is set as K. ave The value is calculated using the following formula (16).

[0108] [Number 10]

[0109]

[0110] Figure 4 This is a graph illustrating the results of this embodiment. Figure 4 (a) shows the residual amount of the melt (m) 3 A graph showing the changes in ( ). Figure 4 (a) The white squares represent the amount of molten material remaining as measured by each discharge operation. Figure 4 (a) The dashed line represents the management value for the residual amount of melt.

[0111] Figure 4 (b) is a graph showing the variation in the height of the molten material. Figure 4 (b) The black squares represent the height of the melt level detected by measurement during each discharge operation. Figure 4(b) The dashed line represents the managed value for the molten material level, and the dotted line represents the height of the duct. That is, in order to prevent the molten material level from reaching the duct position, the managed value for the molten material level is a position lower than the height of the duct. Figure 4 (c) shows the average porosity ε ave A graph showing the variation of (-). Average porosity ε ave (-) is the 1-day moving average of ε. Figure 4 (d) is a graph showing the variation of the ventilation resistance index ratio (-).

[0112] like Figure 4 As shown in (a) and (b), the amount of molten material remaining increased until 20 hours had passed. The molten material level also increased accordingly. After 18 hours, both the amount of molten material remaining and the molten material level exceeded the controlled values, therefore, an operation was implemented to reduce the iron production rate. Consequently, after 20 hours, the amount of molten material remaining began to decrease, and the molten material level decreased accordingly. Figure 4 As shown in (c), the average porosity of the filled structure decreases with increasing residual molten material, and then decreases with decreasing residual molten material. Figure 4 (b) shows that the residual amount of the melt, after becoming 0, begins to increase.

[0113] like Figure 4 As shown in (d), the ventilation resistance index ratio increases with the increase of molten material quantity and molten material level. An increase in the ventilation resistance index ratio indicates a decrease in furnace ventilation; therefore, if the ventilation resistance index ratio increases, the blast furnace operation becomes unstable. However, because the residual amount of molten material was reduced by implementing operations that decreased the molten material production rate after 18 hours, the ventilation resistance index ratio decreased, achieving stable blast furnace operation.

[0114] On the other hand, in the detection of residual molten material in each discharge operation, the residual molten material increased significantly after 18 hours and before 21 hours, and the liquid level of the molten material may reach the tuyere position. Even assuming that the liquid level of the molten material does not reach the tuyere position, the ventilation resistance index ratio increases significantly, and the blast furnace operation becomes unstable, thus making it impossible to achieve stable blast furnace operation.

[0115] Thus, in the molten residue detection method and apparatus according to this embodiment, since the residual amount of molten material in the vertical furnace can be detected at any time, an operation based on the residual amount of molten material can be performed at a desired time. Therefore, compared to the conventional method of detecting the residual amount of molten material for each discharge operation, malfunctions in blast furnace operation can be avoided, and stable blast furnace operation can be achieved. Furthermore, since the residual amount of molten material can be detected without using special sensors or cameras, the increase in iron production costs caused by the initial and maintenance costs of introducing special sensors or cameras can be suppressed.

[0116] Explanation of reference numerals in the attached figures

[0117] 10 furnace main bodies

[0118] 12 Wind Opportunities

[0119] 14 Solid-filled structure

[0120] 16. Molten material (liquid)

[0121] 18 Iron discharge holes (outlet holes)

[0122] 20 Blast Furnace (Container)

[0123] 30 Residue Detection Device

[0124] 31 Manufacturing Speed ​​Acquisition Department (Supply Speed ​​Acquisition Department)

[0125] 32 Discharge speed acquisition section

[0126] 33 Residual Amount Calculation Section

[0127] 34 Liquid Level Calculation Section

[0128] 35 databases

[0129] 41 Furnace Top Gas Analyzer

[0130] 42 air outlet flow meter

[0131] 43 Hygrometer

[0132] 44 air outlet pressure gauge

[0133] 45 Melt thermometer

[0134] 46 Discharge Measurement Instrument

[0135] 47 Discharge time measuring device.

Claims

1. A method for detecting the residual amount of liquid, comprising detecting the residual amount of liquid remaining at the bottom of a container after it has been discharged from a drain hole located at the bottom of the container, in a state where liquid contained within the container having been filled with a solid filling structure to form a solid filling structure and immersed in at least a portion of the voids of the solid filling structure, having been discharged from the container, wherein... The residual amount of liquid is detected by the difference between the liquid supply rate and the liquid discharge rate, wherein the liquid discharge rate is calculated using the discharge acceleration of the liquid from the discharge orifice, the discharge time, and the initial discharge rate. The discharge velocity is calculated using Equation 1, where v is the discharge velocity (m). 3 / sec), v0 is the initial discharge velocity (m 3 / sec), t is the discharge time (sec), and a is the discharge acceleration (m). 3 / sec 2 ), Formula 1: v = v0 + a × t Formula 2: V=V0+∫(PV(t)-v(t×ρ)dt The residual amount of the liquid is determined by Equation 2, where V is the residual amount (kg), V0 is the initial residual amount of the liquid (kg), PV is the manufacturing rate (kg / sec), and v is the discharge rate (m). 3 / sec), ρ is the density of the liquid (kg / m³) 3 ), The porosity of the solid-filled structure is calculated using the inclination angle of the liquid level at the end of the discharge from the discharge orifice. The liquid level after discharge is determined by using the calculated porosity and the amount of liquid remaining after discharge.

2. The method for detecting residual liquid according to claim 1, The amount of liquid discharged at the discharge time is calculated using Equation 3. Formula 3: In Equation 3, V is the discharge volume (m³). 3 T is the discharge time (sec), and a is the discharge acceleration (m). 3 / sec 2 v0 is the initial discharge velocity (m). 3 / sec).

3. The method for detecting residual liquid according to claim 1 or 2, The initial discharge velocity is obtained using equations 4 and 5. Formula 4: In Equation 4, P i-Ο ρ is the pressure difference between the internal pressure of the container and atmospheric pressure (atm), and ρ is the density of the liquid (kg / m³). 3 ), g is the acceleration due to gravity, Z S d is the difference (m) between the initial height of the liquid and the height at the outlet side of the discharge hole. th L is the diameter of the discharge orifice (m), λ is the coefficient of friction of the inner wall of the discharge orifice, and L is the coefficient of friction of the inner wall of the discharge orifice. th v0 is the discharge hole depth (m) and v0 is the initial discharge velocity (m). 3 / sec), Formula 5: In Equation 5, λ is the friction coefficient of the inner wall of the discharge hole, e is the roughness (m) of the inner wall of the discharge hole, and d th ρ is the diameter of the discharge orifice (m), and ρ is the density of the liquid (kg / m³). 3 v0 is the initial discharge velocity (m). 3 / sec), S dh is the cross-sectional area of ​​the discharge hole, and μ is the viscosity of the liquid (Pa·s).

4. The method for detecting residual liquid according to claim 3, The cross-sectional area of ​​the discharge hole is calculated using Equation 6. Formula 6: S dh =(d th / 2) 2 ×π In Equation 6, S dh It is the cross-sectional area of ​​the discharge hole, d th It is the diameter (m) of the discharge port.

5. A method for detecting the residual amount of molten material, comprising: blowing oxygen-containing gas into the lower part of a vertical furnace, generating high-temperature reducing gas by burning carbon, melting and reducing iron source raw material loaded from the top of the vertical furnace and forming a solid filling structure inside the furnace using the high-temperature reducing gas to produce molten material, and discharging the molten material from the tap hole of the vertical furnace; and detecting the residual amount of molten material remaining at the bottom of the vertical furnace after the molten material has been discharged, wherein... The residual amount of the molten material is detected by the difference between the production rate and the discharge rate of the molten material. The discharge rate of the molten material is calculated using the discharge acceleration, discharge time, and initial discharge rate of the molten material from the tap hole. The discharge velocity is calculated using Equation 1, where v is the discharge velocity (m). 3 / sec), v0 is the initial discharge velocity (m 3 / sec), t is the discharge time (sec), and a is the discharge acceleration (m). 3 / sec 2 ), Formula 1: v = v0 + a × t Formula 2: V=V0+∫(PV(t)-v(t×ρ)dt The residual amount of the melt is determined by Equation 2, where V is the residual amount (kg), V0 is the initial residual amount of the melt (kg), PV is the manufacturing speed (kg / sec), and v is the discharge speed (m). 3 / sec), ρ is the density of the melt (kg / m³) 3 ), The porosity of the solid-filled structure is calculated using the inclination angle of the molten material surface at the end of discharge from the tap hole. The liquid level of the melt after discharge is detected using the calculated porosity and the residual amount of the melt after discharge.

6. The method for detecting the residual amount of melt according to claim 5, The amount of molten material discharged over the discharge time is calculated using Equation 3. Formula 3: In Equation 3, V is the discharge volume (m³). 3 T is the discharge time (sec), and a is the discharge acceleration (m). 3 / sec 2 v0 is the initial discharge velocity (m). 3 / sec).

7. The method for detecting the residual amount of melt according to claim 5 or 6, The initial discharge velocity is obtained using equations 4 and 5. Formula 4: In Equation 4, P i-Ο ρ is the pressure difference (atm) between the internal pressure of the vertical furnace and atmospheric pressure, and ρ is the density of the liquid (kg / m³). 3 ), g is the acceleration due to gravity, Z S d is the difference (m) between the height of the molten material at the start of discharge and the height at the outlet side of the taphole. th L is the diameter of the tap hole (m), λ is the coefficient of friction of the inner wall of the tap hole, and L is the coefficient of friction of the inner wall of the tap hole. th V0 is the depth of the tap hole (m), and v0 is the initial discharge velocity (m). 3 / sec), Formula 5: In Equation 5, λ is the coefficient of friction of the inner wall of the tap hole, e is the roughness (m) of the inner wall of the tap hole, and d th ρ is the diameter of the iron outlet (m), and ρ is the density of the liquid (kg / m³). 3 v0 is the initial discharge velocity (m). 3 / sec), S dh is the cross-sectional area of ​​the iron outlet, and μ is the viscosity of the liquid (Pa·s).

8. The method for detecting the residual amount of melt according to claim 7, The cross-sectional area of ​​the iron outlet hole is calculated using Equation 6. Formula 6: S dh =(d th / 2) 2 ×π In Equation 6, S dh It is the cross-sectional area of ​​the iron outlet, d th It is the diameter (m) of the iron outlet.

9. An operating method for a vertical furnace, If the liquid level height detected by the residual melt detection method according to claim 5 exceeds a predetermined threshold, Perform at least one of the following operations: reducing the manufacturing speed of the melt and increasing the discharge speed of the melt.

10. A liquid residue detection device, comprising detecting the amount of liquid remaining at the bottom of a container after it has been discharged from a discharge port provided at the bottom of the container, in a state in which liquid contained within the container having been formed by filling it with a solid filling structure with a solid filling structure and having been immersed into at least a portion of the voids of the solid filling structure, wherein... have: The supply speed acquisition unit acquires the supply speed of the liquid; The discharge velocity acquisition unit obtains the discharge velocity of the liquid using the discharge acceleration, discharge time, and initial discharge velocity of the liquid from the discharge orifice. The discharge velocity is calculated using Equation 1. Formula 1: v = v0 + a × t In Equation 1, v is the discharge velocity (m). 3 / sec), v0 is the initial discharge velocity (m 3 / sec), t is the discharge time (sec), and a is the discharge acceleration (m). 3 / sec 2 ); The residual amount calculation unit calculates the residual amount of liquid using the difference between the liquid supply rate and the liquid discharge rate. The residual amount of liquid is obtained using Equation 2. Formula 2: v=V0+∫(PV(t)-v(t×ρ)dt In Equation 2, V is the residual amount (kg), V0 is the initial residual amount of liquid (kg), PV is the manufacturing rate (kg / sec), and v is the discharge rate (m). 3 / sec), ρ is the density of the liquid (kg / m³) 3 );and The liquid level calculation unit calculates the porosity of the solid filling structure using the inclination angle of the liquid level at the end of the discharge from the discharge hole, and uses the calculated porosity and the residual amount of the liquid after discharge to detect the liquid level after discharge.

11. The liquid residue detection device according to claim 10, It also involves calculating the amount of liquid discharged over the discharge time using Equation 3. Formula 3: In Equation 3, V is the discharge volume (m³). 3 T is the discharge time (sec), and a is the discharge acceleration (m). 3 / sec 2 v0 is the initial discharge velocity (m). 3 / sec).

12. The liquid residue detection device according to claim 10 or 11, The initial discharge velocity is also determined by equations 4 and 5. Formula 4: In Equation 4, P i-Ο ρ is the pressure difference between the internal pressure of the container and atmospheric pressure (atm), and ρ is the density of the liquid (kg / m³). 3 ), g is the acceleration due to gravity, Z S d is the difference (m) between the initial height of the liquid and the height at the outlet side of the discharge hole. th L is the diameter of the discharge orifice (m), λ is the coefficient of friction of the inner wall of the discharge orifice, and L is the coefficient of friction of the inner wall of the discharge orifice. th v0 is the discharge hole depth (m) and v0 is the initial discharge velocity (m). 3 / sec), Formula 5: In Equation 5, λ is the friction coefficient of the inner wall of the discharge hole, e is the roughness (m) of the inner wall of the discharge hole, and d th ρ is the diameter of the discharge orifice (m), and ρ is the density of the liquid (kg / m³). 3 v0 is the initial discharge velocity (m). 3 / sec), S dh is the cross-sectional area of ​​the discharge hole, and μ is the viscosity of the liquid (Pa·s).

13. The liquid residue detection device according to claim 12, It is also configured to calculate the cross-sectional area of ​​the discharge hole using Equation 6. Formula 6: S dh =(d th / 2) 2 ×π In Equation 6, S dh It is the cross-sectional area of ​​the discharge hole, d th It is the diameter (m) of the discharge port.

14. A residual molten material detection device, comprising: a vertical furnace in which oxygen-containing gas is blown into the lower part of the furnace, high-temperature reducing gas is generated by burning carbon, iron source material loaded from the top of the furnace and forming a solid filling structure within the furnace is melted and reduced by the high-temperature reducing gas to produce a molten material, and the molten material is discharged from the tap hole of the furnace; the device detects the residual molten material remaining at the bottom of the furnace after the molten material has been discharged. have: The manufacturing speed acquisition unit acquires the manufacturing speed of the molten material; The discharge speed acquisition unit obtains the discharge speed of the molten material using the discharge acceleration, discharge time, and initial discharge speed from the tap hole. This discharge speed is calculated using Equation 1. Formula 1: v = v0 + a × t In Equation 1, v is the discharge velocity (m). 3 / sec), v0 is the initial discharge velocity (m 3 / sec), t is the discharge time (sec), and a is the discharge acceleration (m). 3 / sec 2 ); The residual amount calculation unit calculates the residual amount of the molten material using the difference between the manufacturing rate and the discharge rate of the molten material. The residual amount of the molten material is obtained using Equation 2. Formula 2: V=V0+∫(PV(t)-v(t×ρ)dt In Equation 2, V is the residual amount (kg), V0 is the initial residual amount of the melt (kg), PV is the manufacturing rate (kg / sec), and v is the discharge rate (m). 3 / sec), ρ is the density of the melt (kg / m³) 3 );and The liquid level calculation unit calculates the porosity of the solid filling structure using the inclination angle of the liquid level of the molten material at the end of the discharge from the iron outlet, and uses the calculated porosity and the residual amount of the molten material after discharge to detect the liquid level height of the molten material after discharge.

15. The residual amount detection device for molten material according to claim 14, It also involves calculating the amount of molten material discharged over the discharge time using Equation 3. Formula 3: In Equation 3, V is the discharge volume (m³). 3 T is the discharge time (sec), and a is the discharge acceleration (m). 3 / sec 2 v0 is the initial discharge velocity (m). 3 / sec).

16. The residual amount detection device for melt according to claim 14 or 15, The initial discharge velocity is also determined by equations 4 and 5. Formula 4: In Equation 4, P i-Ο ρ is the pressure difference (atm) between the internal pressure of the vertical furnace and atmospheric pressure, and ρ is the density of the molten material (kg / m³). 3 ), g is the acceleration due to gravity, Z S d is the difference (m) between the height of the molten material at the start of discharge and the height at the outlet side of the taphole. th L is the diameter of the tap hole (m), λ is the coefficient of friction of the inner wall of the tap hole, and L is the coefficient of friction of the inner wall of the tap hole. th V0 is the depth of the tap hole (m), and v0 is the initial discharge velocity (m). 3 / sec), Formula 5: In Equation 5, λ is the coefficient of friction of the inner wall of the tap hole, e is the roughness (m) of the inner wall of the tap hole, and d th ρ is the diameter of the iron outlet (m), and ρ is the density of the liquid (kg / m³). 3 v0 is the initial discharge velocity (m). 3 / sec), S dh is the cross-sectional area of ​​the iron outlet, and μ is the viscosity of the liquid (Pa·s).

17. The residual amount detection device for molten material according to claim 16, It is also configured to calculate the cross-sectional area of ​​the iron outlet hole using Equation 6. Formula 6: S dh =(d th / 2) 2 ×π In Equation 6, S dh It is the cross-sectional area of ​​the iron outlet, d th It is the diameter (m) of the iron outlet.

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