WO2001096617A1 - Procede permettant d'observer a l'interieur d'un four d'affinage de fer en fusion et tuyere permettant d'observer a l'interieur de ce four - Google Patents

Procede permettant d'observer a l'interieur d'un four d'affinage de fer en fusion et tuyere permettant d'observer a l'interieur de ce four Download PDF

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Publication number
WO2001096617A1
WO2001096617A1 PCT/JP2001/004975 JP0104975W WO0196617A1 WO 2001096617 A1 WO2001096617 A1 WO 2001096617A1 JP 0104975 W JP0104975 W JP 0104975W WO 0196617 A1 WO0196617 A1 WO 0196617A1
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WO
WIPO (PCT)
Prior art keywords
tuyere
furnace
molten iron
gas
observation
Prior art date
Application number
PCT/JP2001/004975
Other languages
English (en)
Japanese (ja)
Inventor
Shinya Kitamura
Tsuyoshi Yamazaki
Original Assignee
Nippon Steel Corporation
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Nippon Steel Corporation filed Critical Nippon Steel Corporation
Priority to BR0106724-9A priority Critical patent/BR0106724A/pt
Priority to CA002381584A priority patent/CA2381584A1/fr
Priority to AU62753/01A priority patent/AU757791B2/en
Priority to KR1020027001891A priority patent/KR20020025219A/ko
Priority to EP01936979A priority patent/EP1291444A4/fr
Priority to JP2002510729A priority patent/JP5014555B2/ja
Publication of WO2001096617A1 publication Critical patent/WO2001096617A1/fr

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
    • C21C5/28—Manufacture of steel in the converter
    • C21C5/42—Constructional features of converters
    • C21C5/46—Details or accessories
    • C21C5/4673—Measuring and sampling devices
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D21/00—Arrangements of monitoring devices; Arrangements of safety devices
    • F27D21/02—Observation or illuminating devices
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
    • C21C5/28—Manufacture of steel in the converter
    • C21C5/42—Constructional features of converters
    • C21C5/46—Details or accessories
    • C21C5/48—Bottoms or tuyéres of converters
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
    • F27B3/00—Hearth-type furnaces, e.g. of reverberatory type; Tank furnaces
    • F27B3/10—Details, accessories, or equipment peculiar to hearth-type furnaces
    • F27B3/28—Arrangement of controlling, monitoring, alarm or the like devices
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D21/00—Arrangements of monitoring devices; Arrangements of safety devices
    • F27D21/0014—Devices for monitoring temperature

Definitions

  • the present invention relates to a method for measuring the temperature and / or composition of molten iron in a refining furnace through a tube penetrating a refractory from a furnace wall and / or a furnace bottom of a molten iron refining furnace such as a converter, A0D, and RH.
  • the present invention relates to a method and a tuyere capable of stable observation in a single tube tuyere for non-contact observation by detecting an electromagnetic wave radiated from a metal.
  • a method of non-contact observation of the temperature and composition of molten iron in a refining furnace typified by a converter through a tube that penetrates the refractory from the furnace wall to the furnace bottom has been known for some time.
  • the temperature of the molten iron in the refining furnace can be determined by a method using an image fiber as disclosed in JP-A-11-142246 or an optical fiber as disclosed in JP-A-01-314928. There is a method using a laser beam as disclosed in JP-A-60-42644 for the molten iron component in the refining furnace.
  • the present invention provides a method and an observation tuyere that constantly open the observation tuyere according to the state of the scouring, thereby enabling stable observation of the temperature and temperature or composition of the molten iron in the refining furnace. .
  • the gist of the present invention resides in the following methods.
  • the temperature, Z or composition of the molten iron in the refining furnace is detected through a tube that penetrates the refractory from the furnace wall and / or furnace bottom of the molten iron refining path, and electromagnetic waves radiated from the molten metal at the tuyere tip
  • a single-tube tuyere for non-contact observation is used, and an inert gas and an oxidizing gas are used alone or in combination according to the opening condition of the tuyere tip.
  • Furnace observation method Here, the inert gas, indicated Ar, nitrogen, CO, and the oxidizing gas, shows the oxygen, air, C0 2.
  • the opening period when the opening ratio is larger than a (stationary period), a method for observing the inside of a molten iron smelting furnace that supplies only inert gas.
  • the opening period is determined based on the fact that the measured molten iron temperature at the tuyere tip has reached 1800 ° C or higher, and ends.
  • the upper limit of the aperture ratio is Although not specified, it is desirable that it is 95% or less to prevent tuyere erosion.
  • the temperature and Z or composition of the molten iron in the furnace by detecting the electromagnetic waves radiated from the molten metal at the tip of the tuyere through a tube that penetrates the refractory from the furnace wall and / or the furnace bottom of the molten iron furnace.
  • a single-tube tuyere for non-contact observation is used to control the flow rate of inert gas in accordance with the state of opening at the tip of the tuyere.
  • the inert gas refers to Ar, nitrogen, and CO.
  • the molten iron temperature and the temperature are set so that the opening ratio (%) of the single-tube tuyere becomes ⁇ or more and 95% or less calculated by the formula (1) based on the tuyere inner diameter r (mm).
  • a method for observing the inside of a molten iron furnace that controls the flow rate of inert gas according to its composition.
  • a single-tube tuyere for non-contact observation, and an inert gas and an oxidizing gas can be used alone or mixed depending on the opening of the tuyere pipe with an inner diameter of 2 to 6 mm.
  • the opening ratio of the inner tube tuyere tip is detected using a double tube tuyere, and the gas flow rate of the inner and outer tubes and / or A method for in-furnace observation of a molten iron furnace that changes the composition to control the mushroom size at the tip of the inner tube tuyere and maintains the opening ratio required for observation.
  • r is the inner tube tuyere inner diameter (mm).
  • the tuyere opening that increases the aperture ratio by supplying a mixed gas of inert gas and oxidizing gas or only oxidizing gas from the outer tube
  • a method for observing the inside of a molten iron refining furnace in which tuyere cooling gas and inert gas are supplied singly or as a mixture from the outer tube.
  • FIG. 4 is a diagram showing the relationship between the diameter of the opening of the tuyere for observation (K), the diameter of the mashroom (M) generated at the tip of the tuyere, and the inner diameter of the tuyere (r).
  • FIG. 9 is a diagram showing the relationship between the aperture ratio and the accuracy of radiation temperature measurement when a tuyere with an inner diameter of 10 mm is used.
  • FIG. 2 is a schematic view of a double tube tuyere for in-furnace observation according to the present invention.
  • the present invention has a novel relationship that there is a correlation between the opening area of the tuyere for observation and the size of the mashroom generated at the tip of the tuyere, and that the opening area can be controlled by controlling the size of the mushroom.
  • Fig. 1 shows the results of a detailed experiment conducted by the present inventors using a 1-ton scale melting furnace.
  • the inner diameter of the tuyere inner tube is]: and the diameter of the opening of the observation tuyere is: If the diameter of the mushroom formed at the tip is M, there is a strong correlation between M / r and K / r as shown in Fig. 1.
  • the gas flow rate and composition must be adjusted. You just have to change it to control the mushroom size.
  • the electromagnetic wave is a general term for light having a wavelength unique to each component in radiation temperature measurement and each component in laser emission analysis.
  • a single tube tuyere is defined as a gas composition system.
  • the capital investment amount is small because it is used alone, and the double tube tuyere is used because the gas composition and flow rate of the inner and outer tubes can be controlled independently.
  • the gas used for the inner and outer tubes is a tuyere cooling gas, an inert gas, or an oxidizing gas alone or as a mixture of two or more types.
  • the tuyere cooling gas for the outer tube is a gas represented by LPG
  • the inert gas for the inner tube is Ar, nitrogen, and carbon monoxide gas
  • the oxidizing gas is oxygen, air, and carbon dioxide.
  • the first aspect of the present invention is to control the temperature, Z, or composition of molten iron in a refining furnace through a tube penetrating a refractory from a furnace wall and / or a furnace bottom of a molten iron refining furnace represented by a converter, an electric furnace, and A0D.
  • an inert gas and oxidizing In the single-tube tuyere, which is a method for observing the inside of a molten metal furnace using an inert gas alone or as a mixture, an inert gas and an oxidizing gas may be used alone or mixed depending on the opening condition of the tuyere tip. To use it.
  • the observation is to detect the electromagnetic wave radiated from the interface between the molten iron surface and the blown gas bubble at the tuyere tip, so that the intensity of the electromagnetic wave is sufficient to be determined according to the observation method.
  • the opening ratio at the tuyere tip is controlled by the gas composition.
  • the inert gas indicated Ar, nitrogen, CO, and the oxidizing gas, shows the oxygen, air, C0 2.
  • the inert gas indicated Ar, nitrogen, CO, and the oxidizing gas
  • the inert gas shows the oxygen, air, C0 2.
  • the second aspect of the present invention specifies a specific control method in the first aspect.
  • the aperture area required for observation differs between the case where the intensity of the electromagnetic wave is strong, such as when the observation target is temperature, and the case where the intensity is weak, such as laser emission light for component analysis. It also depends on the tuyere inner diameter and tuyere length. In general it tuyere length becomes a 1 about 2 m Given the refractory Thickness large converter, it has been experimentally known that if it is necessary observation plane product of 6 mm 2 . Equation (1) is a mathematical expression of this.
  • the opening ratio (%) of the tuyere is less than the value calculated by the formula (1) using the tuyere inner diameter r (mm), the mixed gas of the inert gas and the oxidizing gas, or
  • This is a furnace observation method for a molten iron furnace that supplies only oxidizing gas (opening period) and supplies only inert gas when the opening ratio is larger than a (stationary period).
  • the aperture ratio is a percentage value obtained by dividing the area of the opening area not covered by the mushroom at the tuyere tip by the tuyere cross-sectional area, and the relationship between the aperture ratio and the gas back pressure is determined in advance. When measured, it can be detected by a change in gas back pressure, and can also be detected directly by observation with an image fiber installed at the tip of the tuyere on the steel skin side.
  • FIG. 2 shows an example in which the present invention is applied to radiation temperature measurement using an image fiber.
  • the accuracy of the vertical axis corresponds to 2 ⁇ ( ⁇ is the standard deviation) of the measured temperature. From this, it can be seen that the temperature can be accurately observed when ⁇ X r 2 is 765 or more.However, when a X r 2 is smaller than 765, the observation field of view becomes narrow due to occlusion, so that the observation accuracy is reduced. Decreases I have.
  • the critical value required for the observation aperture ratio of the tuyere is smaller than a X r 2 force S76 5, the tuyere pipe inner diameter, molten iron temperature, depending on the molten iron carbon content, oxygen, air, C0 2 in the oxidizing gas flow, Ar, nitrogen, will control the adjusting aperture ratio one or more kinds of inert gas flow rate of CO.
  • the mushroom diameter at the tuyere tip which serves as a guideline for control, can be calculated from the thermal balance of the following items, and can be controlled by obtaining an experimental relationship between the mushroom diameter and the aperture ratio. Become.
  • a, b and n are constants and Q is the total gas flow rate (Nm 3 Zh / t) and T are hot metal temperature (° C) and Ts is solidus temperature (° C).
  • t 1 and V 2 can be calculated from the physical properties of the gas used and the heat of reaction if the contribution to mushroom formation is determined experimentally, and Ts can be determined from a phase diagram. If these are put into Eq. (2) and constants are determined so as to match the experimentally obtained mushroom diameter, an expression for estimating the mushroom diameter in the actual machine can be obtained.
  • j3 takes a value of 1.0 to 1.3.
  • the third aspect of the present invention is to radiate the temperature and / or composition of the molten iron in the refining furnace from the molten metal at the tip of the tuyere through a pipe penetrating the refractory from the furnace wall and / or the furnace bottom of the molten iron refining furnace.
  • the opening ratio at the tuyere tip is too small, the observation accuracy will be reduced, and the tuyere is generated at the tuyere tip by reducing the inert gas flow rate and reducing the cooling capacity by gas sensible heat. Dissolve the mash room, and conversely, if the opening ratio at the tip of the tuyere is too large, the tuyere melting is large, so observe by increasing the inert gas flow rate and increasing the cooling capacity by gas sensible heat. Generate mashrooms within a range that does not reduce accuracy.
  • the fourth and fifth aspects of the present invention specify a specific control method in the third aspect of the present invention.
  • the equation (1) is obtained by the tuyere opening ratio (%) force and the tuyere inner diameter r (mm).
  • the flow rate of the inert gas is controlled so that it is not less than ⁇ ; 95% or less, and the flow rate of the inert gas is controlled according to the temperature and composition of the molten iron. is there.
  • the aperture ratio If it is larger than 95%, the mushroom at the tip of the tuyere is too small to protect the tuyere and the tuyere life is short.
  • the carbon concentration is estimated from a method of calculating from the amount of supplied acid and the empirically known decarbonation efficiency based on the carbon concentration of the molten iron charged, from an exhaust gas analysis and direct sampling of molten iron. It can be estimated by any of these methods, or by a combination thereof.
  • the method of knowing the temperature by direct continuous or semi-continuous temperature measurement, or the method of calculating from the empirical heating efficiency based on the temperature of the charged molten iron, or These combinations can be estimated.
  • the reason why the inert gas flow rate is controlled according to the temperature and composition of the molten iron is that the size of the mushroom is greatly affected by the difference between the molten iron temperature and the solidus temperature of the molten iron. This is because it is necessary to detect the difference from the solidus temperature determined by the molten iron composition (particularly the carbon concentration), and to increase or decrease the flow rate of the inert gas based on the detected value.
  • the mushroom diameter at the tip of the tuyere which can be used as a guide for control, can be calculated using the following thermal parameters, and is controlled by finding the experimental relationship between the mushroom diameter and the aperture ratio. It becomes possible.
  • a, b, and n are constants
  • Q is the total gas flow rate (Nm 3 h h Z t)
  • T is the hot metal temperature (° C)
  • Ts is the solidus temperature (° C).
  • ⁇ 1 can be calculated from the physical properties of the gas used, and Ts can be obtained from a phase diagram. If these are put into Eq. (4) and the constants are determined to match the mushroom diameter experimentally obtained, the pine on the actual machine can be obtained. An expression for estimating the shroom diameter can be obtained.
  • the relationship between the mashroom diameter M and the equivalent circle diameter K of the opening can be calculated by equation (3).
  • the temperature and / or composition of the molten iron in the refining furnace is determined through a pipe that penetrates the refractory from the furnace wall and the _ or the furnace bottom as shown in one embodiment in FIG.
  • Single-tube tuyere for non-contact observation by detecting electromagnetic waves radiated from the molten metal at the tuyere tip.
  • Insertt gas and oxidizing gas depending on the opening condition at the tuyere tip This is a tuyere for observation in a furnace of a molten metal refining furnace having a control function that can be used alone or as a mixture.
  • the inside diameter of the tuyere is 2 to 6 mm. If it is smaller than 2 mm, mushrooms cannot be generated to secure the opening area required for observation, and the tuyere life is short. On the other hand, if the diameter is larger than 6 mm, the gas flow rate becomes large, so the gas cost is high and it is not economical.
  • the sixth aspect of the present invention is the observation of electromagnetic waves radiated from the interface between the molten iron surface at the tip of the inner tube tuyere and the injected gas bubbles. It is necessary to control the opening ratio at the tip of the inner tube tuyere with the gas composition and flow rate of the inner and outer tubes so that the intensity of the electromagnetic wave is sufficient for the required intensity according to the observation method.
  • the aperture ratio is detected by changes in gas back pressure and observation by an image fiber installed at the tip of the tuyere on the steel skin side. Based on the detected aperture ratio, the gas flow rate and the Z or composition of the inner and outer pipes are changed to control the mushroom size according to the change, thereby maintaining the aperture ratio required for observation.
  • a seventh aspect of the present invention is a specific control method according to the sixth aspect, wherein the tuyere opening is controlled by controlling the cooling capacity of the outer tube in accordance with the temperature and composition of the molten iron.
  • This is a method to keep the mouth ratio always higher than the critical value required for observation.
  • the tuyere is changed by changing the gas flow rate and / or composition of the tuyere cooling gas, inert gas, and oxidizing gas in the outer tube according to the mashroom size estimated based on the temperature and composition of the molten iron.
  • the aperture ratio (%) is maintained within the range of not less than ⁇ (%) and not more than 95% in equation (5).
  • r is the inner tube tuyere inner diameter (mm), and since r is desirably 3 mm or more, it takes a value smaller than 95%. Further, at this time, it is desirable that the inner pipe always supply an inert gas.
  • the aperture ratio is a value obtained by dividing the area of the opening area that is not covered with the mushroom at the tuyere tip by the tuyere cross-sectional area as a percentage.
  • the critical value of the aperture ratio differs between when the intensity of the electromagnetic wave is high, such as when the observation target is temperature, and when it is weak, such as laser emission light for component analysis. It also depends on the length of the mouth. In general it tuyere length is given the refractory thickness large converter 1 to about 2 m, in that case, it has been experimentally known are required 6 mm 2 or more observation area . Formula (5) is obtained by formulating this.
  • the equation (5) is obtained. If the aperture ratio is smaller than this, the observation accuracy decreases due to the small opening area of the tuyere tip, and if the aperture ratio is greater than 95%, the mushroom at the tuyere tip is too small. Tuyere cannot be protected and tuyere life is short.
  • Figure 3 shows an example of the accuracy of radiation temperature measurement using an image fiber with an inner diameter of 10 mm, and the accuracy on the vertical axis was measured. It corresponds to 2 ⁇ of temperature ( ⁇ is the standard deviation). From this, it can be seen that the temperature can be accurately observed when the aperture ratio is 8.5% or more (corresponding to ⁇ in the equation (5)), but when the aperture ratio is smaller than 8.5%, the temperature is closed. Obstruction narrows the observation field of view and reduces observation accuracy.On the other hand, if the aperture ratio is greater than 95%, the aperture ratio is too large and mashrooms are not sufficiently generated and tuyere erosion occurs. Is big.
  • the present invention is based on the new finding that the size of the mushroom generated at the tip of the tuyere, which is closely related to the opening area of the tuyere for observation, is more affected by the outer tube gas than the inner tube gas. It was done. Therefore, in order to control the opening ratio of the tuyere, it was decided to control the gas flow rate and the composition or composition of the outer tube.
  • LPG can be exemplified as the tuyere cooling gas of the outer tube, Ar, nitrogen, carbon monoxide gas as the inert gas, and oxygen, air and carbon dioxide as the oxidizing gas.
  • the aperture ratio is to be 95% or less, perform one or more of the following functions (1) to (3) to reduce the temperature at the tip of the tuyere outer tube, grow mushrooms, and make the tuyere To protect.
  • the inner tube is always made of an inert gas, there is no effect on the measurement of electromagnetic waves. 1 Increase the inert gas flow rate.
  • the matsushroom formation behavior is greatly affected by the composition and temperature of the molten iron, so control must be performed according to the composition and temperature of the molten iron.
  • the carbon concentration is determined based on the carbon concentration of the charged molten iron. It can also be estimated from the method of calculating from the amount of acid and the empirically known decarboxylation efficiency, the method of estimating from exhaust gas analysis or direct sampling of molten iron, or a combination thereof.
  • the temperature can also be estimated by calculating from the empirical heating efficiency based on the temperature of the charged molten iron.
  • the diameter M of the mushroom generated at the tuyere tip is controlled as MZr.
  • Estimation of the pine room diameter M can be calculated from the heat balance of each of the following items 1) to 4).
  • Cooling index by inner tube gas sensible heat 3) Function of inner tube gas specific heat
  • Q is the total gas flow rate (Nm 3 Z h / t)
  • T hot metal temperature C
  • Ts solidus temperature determined by molten iron composition Degrees (° C).
  • ul, v 2, ⁇ 3 can be calculated from the physical properties of the gas used and the heat of reaction if the contribution to matsushroom formation is determined experimentally, and Ts can be obtained from a phase diagram, etc. . If these are put into Eq. (7) and the constants are determined so as to match the mushroom diameter experimentally obtained, an equation for estimating the mushroom diameter in an actual machine can be obtained.
  • An eighth aspect of the present invention is a method in which an oxidizing gas is supplied from an inner tube to open the tuyere when the tuyere is closed.
  • the tuyere opening ratio is smaller than the percentage (%) in equation (5), supply a mixed gas of inert gas and oxidizing gas or only oxidizing gas from the inner tube.
  • a tuyere opening period is set up to increase the opening ratio, and only the inert gas is supplied from the inner pipe during periods other than the tuyere opening period.
  • the tuyere opening period refers to the period from the time when the opening ratio becomes smaller than the initial value and the opening operation is performed to the time when the opening ratio becomes 95% or more.
  • the opening ratio cannot be measured due to the high temperature, according to the knowledge of the present inventors, it is determined that the tuyere tip temperature has reached 1800 ° C. or higher, and that the tuyere opening period can be completed by judging that the tuyere is open.
  • As an action for opening perform one or more of the following actions (1) and (2) to raise the temperature of the tuyere tip and melt the mushroom.
  • the reason why the opening action is performed from the inner pipe is that the gas flow rate can be increased, so that the opening can be reliably performed in a short time.
  • KZ r becomes 1 or more.
  • the fact that KZ r is 1 means that the aperture diameter and the tuyere It means that the diameter is the same, that is, it is completely open. Therefore, in the case of blockage, an action is taken to reduce MZr to 2 or less, and KZr is increased to 1 or more to open.
  • the estimation of the mushroom diameter M can be calculated by the heat balance of the following items.
  • ⁇ 1 ′, V 2 ′, V 3 ′, and V 4 ′ can be calculated from the physical properties of the gas used and the heat of reaction by determining the contribution to matsushroom formation by experiment. Etc. If these are put into Eq.
  • the ninth aspect of the present invention shows another opening method when the tuyere is closed.
  • the inert gas is always supplied from the inner tube, and the opening ratio of the tuyere is smaller than that of Q! Shown by the formula (5).
  • a tuyere opening period is provided to increase the opening ratio by supplying a mixed gas of an inert gas and an oxidizing gas or only an oxidizing gas from the outer tube. Supply the tuyere cooling gas and the inert gas alone or as a mixture from the outer tube. As an opening function, perform one or more of the following functions (1) to (3) to raise the temperature of the tuyere tip and dissolve the mushrooms.
  • the reason why the inner pipe is always opened with the outer pipe gas as the inert gas is as follows. That is, for example, when observing short-wavelength light emitted from a laser or the like, such as carbon or phosphorus, the absorption of oxygen in the pipe is large.
  • the tube must be kept in an inert gas atmosphere.
  • the tuyere can be opened by controlling the gas composition of the outer tube even if the inner tube is always inert gas.
  • the diameter M of the matsushroom generated at the tuyere tip is set to 2 or less as M / r.
  • the estimation of the mushroom diameter M can be calculated by the heat balance of the following items.
  • Cooling index due to outer tube gas latent heat ( ⁇ 2 '' '): Cooling index of outer tube gas reaction heat
  • Cooling index by inner tube gas sensible heat ( ⁇ 3 '''): 4) Heat receiving index from molten iron of mushroom ( ⁇ ,,) When the mushroom is a hemisphere, the following thermal balance is established.
  • a tenth aspect of the present invention provides a tuyere for implementing the furnace observation method of the present invention.
  • the double tube tuyere was used to independently control the gas composition and flow rate of the inner and outer tubes.
  • the opening ratio at the tip of the inner tube tuyere is detected, and the gas flow and / or composition of the inner and outer tubes is controlled based on the information.
  • the tuyere has a concentric double pipe structure composed of an inner pipe 1 and an outer pipe 2 penetrating through the refractory furnace e as shown in FIG.
  • the outer pipe 2 are independent pipes, and the gas flow rate and Z are independent via the inner pipe gas supply pipe 7 and the outer pipe gas supply pipe 8 independently connected to the gas composition and flow rate control device.
  • the gas composition can be controlled.
  • the inner diameter of the observation tuyere is defined as 5 to 20 mm. If it is smaller than 5 mm, it is not possible to generate a mash to secure the opening area required for observation, and the tuyere life will be shortened. Also, if it is larger than 20mm Is not economical due to the high gas flow rate,
  • a 3 ton scale top-bottom blow converter was used.
  • the observation tuyere used a single-tube tuyere with a diameter of 4 mm provided at the furnace bottom ( ⁇ in equation (1) is 47.8). Nitrogen alone or a mixed gas of Ar and oxygen was used from the tuyere. [C] was charged 4.2%, [Mn] was 0.16%, [Si] was 0.21%, and [ ⁇ ] was SO.085% of molten iron.
  • the molten iron temperature at the start of the acid blowing was 1315 ° C. Where 0/0 The same applies hereinafter means weight percent.
  • the components of the blow stopper were [C] 0.04%, [Mn] 0.07%, [Si] 0.01%, [P] 0.017%, and the temperature was 1657 ° C.
  • the radiation temperature was measured by an image fiber through the observation tuyere, and a laser was irradiated through the tuyere, and the carbon emission was observed to measure the carbon concentration.
  • the aperture ratio was measured from the image obtained by image fiber observation, and the gas composition and flow rate were controlled according to the change.
  • Comparative Example 1 'Comparative Example 1 was operated under the conditions shown in Table 3 and the Ar flow rate was constant regardless of the carbon concentration and temperature. As a result, the aperture ratio decreased at the end of refining, making observation impossible. Table 3
  • the test was performed using a 3-ton scale top-bottom blow converter.
  • the observation tuyere used was a double tube tuyere with an inner tube tuyere inner diameter of 10 to 15 mm and a gap of 1 mm between the inner tube and the outer tube.
  • Nitrogen and / or Z or oxygen were used from the inner tube, and one or more of nitrogen, oxygen and LPG were used from the outer tube.
  • [C] was 4.2%
  • [Mn] was 0.16%
  • [Si] was 0.21%
  • [P] was 0.085%.
  • the temperature of molten iron at the start of blowing acid was 1315 ° C.
  • % means mass percentage.
  • the components of the blow stopper were [C] 0.04%, [Mn] 0.07%, [Si] 0.01%, [P] 0.017%, and the temperature was 1657 ° C.
  • Radiation temperature measurement was performed using an image fiber using the observation tuyere, etc., and a laser was irradiated from the inner tube, and the carbon emission was observed to measure the carbon concentration.
  • the aperture ratio was measured from the image obtained by observing the image of the inner tube, and the gas composition and flow rate of the inner and outer tubes were changed to control the mushroom size at the tip of the inner tube tuyere.
  • the insertion limit flow (F; Nm 3 / h) was calculated by the following formula.
  • Example 4 the preconditions were the same as in Example 3, and a double tube tuyere with an inner tube tuyere inner diameter of 10 mm was used.
  • the outer tube gas composition and flow rate were controlled appropriately while estimating the mushroom size for each concentration and temperature. As a result, accurate temperature measurement and carbon concentration analysis were possible throughout the entire purification period.
  • the inner pipe flow rate was fixed at 1.5 times the insertion limit flow rate.
  • ⁇ in equation (5) is 8.5% because the inner diameter is 10 mm. Table 5
  • Example 5 the preconditions were the same as in Example 3, and a double tube tuyere with an inner tube tuyere inner diameter of lOmin was used, but the initial heating rate was slow.
  • ] Approx. 2.4%
  • temperature approx. 1400 ° C (Fig. 6). Therefore, the mushroom size at the tip of the inner tube tuyere was controlled by changing the gas composition and flow rate of the outer tube under the conditions shown in (1) or (2) in Table 6, and as a result, it was reopened and thereafter accurate throughout the refining period. Temperature measurement and carbon concentration analysis were possible.
  • Haitai temperature Inner tube Nm 3 / h / t
  • Outer tube Nm 3 / h / t Opening ratio
  • the present invention 2.4 1400 0.036 0 0.01 0.0018 82 ⁇ 93 2.6 ⁇ 3.4
  • Comparative Example 2 a double tube tuyere with an inner tube tuyere inner diameter of 15 mm was used, and the operation was performed under the conditions shown in Table 7 with the outer tube nitrogen flow rate constant regardless of the carbon concentration and temperature. As a result, the aperture ratio decreased during the middle stage of the refining, making observation impossible, and at the end of the refining period, the mushrooms dissolved and the tuyere for observation was damaged.
  • the observation tuyere is always opened according to the refining situation, and stable observation of the temperature and / or composition of the molten iron in the refining furnace becomes possible.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Carbon Steel Or Casting Steel Manufacturing (AREA)
  • Refinement Of Pig-Iron, Manufacture Of Cast Iron, And Steel Manufacture Other Than In Revolving Furnaces (AREA)

Abstract

La présente invention concerne un procédé permettant d'observer l'intérieur d'un four d'affinage de fer en fusion, qui consiste à utiliser un gaz inerte et un gaz oxydant individuellement ou en combinaison, conformément à la position de la chapelle de l'extrémité avant d'une tuyère à tuyau simple ou double. Ces gaz permettent d'observer sans contact la température et/ou la composition du métal en fusion dans le four d'affinage par la détection d'une onde électromagnétique émise à partir de l'extrémité avant de la tuyère via le tuyau passant à travers un matériau réfractaire de la paroi et/ou du fond du four d'affinage de fer en fusion. Ce procédé permet, à des fins d'observation, d'ouvrir une tuyère de façon régulière conformément au stade d'affinage, ce qui permet d'observer régulièrement la température et/ou la composition du fer en fusion à l'intérieur d'un four d'affinage.
PCT/JP2001/004975 2000-06-12 2001-06-12 Procede permettant d'observer a l'interieur d'un four d'affinage de fer en fusion et tuyere permettant d'observer a l'interieur de ce four WO2001096617A1 (fr)

Priority Applications (6)

Application Number Priority Date Filing Date Title
BR0106724-9A BR0106724A (pt) 2000-06-12 2001-06-12 Método de observação interna de um forno de refino de ferro fundido e ventaneira para observação do interior do forno
CA002381584A CA2381584A1 (fr) 2000-06-12 2001-06-12 Procede permettant d'observer a l'interieur d'un four d'affinage de fer en fusion et tuyere permettant d'observer a l'interieur de ce four
AU62753/01A AU757791B2 (en) 2000-06-12 2001-06-12 Method for observing inside of molten iron refining furnace and tuyere for observing inside of furnace
KR1020027001891A KR20020025219A (ko) 2000-06-12 2001-06-12 용선 정련노의 내측 관찰방법 및 노의 내측 관찰용 송풍구
EP01936979A EP1291444A4 (fr) 2000-06-12 2001-06-12 Procede permettant d'observer a l'interieur d'un four d'affinage de fer en fusion et tuyere permettant d'observer a l'interieur de ce four
JP2002510729A JP5014555B2 (ja) 2000-06-12 2001-06-12 溶鉄精錬炉の炉内観察方法

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
JP2000-175591 2000-06-12
JP2000175592 2000-06-12
JP2000-175592 2000-06-12
JP2000175591 2000-06-12

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WO2001096617A1 true WO2001096617A1 (fr) 2001-12-20

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EP (1) EP1291444A4 (fr)
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CN (1) CN1383454A (fr)
AR (1) AR028710A1 (fr)
AU (1) AU757791B2 (fr)
BR (1) BR0106724A (fr)
CA (1) CA2381584A1 (fr)
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Cited By (2)

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Publication number Priority date Publication date Assignee Title
JP2004037163A (ja) * 2002-07-01 2004-02-05 Nippon Steel Corp 溶融金属の測温装置
JP2017179598A (ja) * 2016-03-29 2017-10-05 Ｊｆｅスチール株式会社 底吹き転炉の炉底羽口健全性評価方法、炉底羽口寿命延長方法及び底吹き転炉の操業方法

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2574474B1 (fr) 2002-05-13 2014-07-09 Dymo Imprimante d'étiquettes
AT514132B1 (de) * 2013-03-25 2015-11-15 Voestalpine Stahl Gmbh Verfahren zur Bestimmung von Reaktionsdaten eines Reaktionsablaufs

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JPS60129628A (ja) * 1983-12-16 1985-07-10 Sumitomo Metal Ind Ltd 溶鋼温度連続測定方法
JPH08165506A (ja) * 1994-12-12 1996-06-25 Nkk Corp 精錬用羽口の損耗抑制方法

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KR0134654B1 (ko) * 1993-10-05 1998-04-20 이요시 슌키치 광파이버를 사용한 온도측정장치 및 방법
US6071466A (en) * 1996-10-17 2000-06-06 Voest Alpine Industries, Inc. Submergible probe for viewing and analyzing properties of a molten metal bath
JP3392736B2 (ja) * 1997-11-10 2003-03-31 新日本製鐵株式会社 溶融金属の測温装置
JPH11281485A (ja) * 1998-03-31 1999-10-15 Nippon Steel Corp 溶鋼の連続測温方法
JPH11326061A (ja) * 1998-05-20 1999-11-26 Sumitomo Metal Ind Ltd 炉内溶湯の温度測定方法及び装置

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JPS60129628A (ja) * 1983-12-16 1985-07-10 Sumitomo Metal Ind Ltd 溶鋼温度連続測定方法
JPH08165506A (ja) * 1994-12-12 1996-06-25 Nkk Corp 精錬用羽口の損耗抑制方法

Non-Patent Citations (1)

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Title
See also references of EP1291444A4 *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004037163A (ja) * 2002-07-01 2004-02-05 Nippon Steel Corp 溶融金属の測温装置
JP2017179598A (ja) * 2016-03-29 2017-10-05 Ｊｆｅスチール株式会社 底吹き転炉の炉底羽口健全性評価方法、炉底羽口寿命延長方法及び底吹き転炉の操業方法

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EP1291444A4 (fr) 2004-03-17
AR028710A1 (es) 2003-05-21
US20020180124A1 (en) 2002-12-05
CA2381584A1 (fr) 2001-12-20
TW558568B (en) 2003-10-21
AU757791B2 (en) 2003-03-06
JP5014555B2 (ja) 2012-08-29
BR0106724A (pt) 2002-04-23
KR20020025219A (ko) 2002-04-03
EP1291444A1 (fr) 2003-03-12
AU6275301A (en) 2001-12-24

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