JP2015067875A - Lance equipment, refining furnace using the same, and lance positioning method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: lance equipment capable of positioning a lance for blowing reactant gas to an adequate position independently of the absolute position of the surface of the molten metal in a refining furnace; a refining furnace using the lance equipment; and a lance positioning method.SOLUTION: Lance equipment 20 for blowing reactant gas onto molten metal in a refining furnace includes: a lance 21 configured to blow the reactant gas; a driving mechanism 24 configured to move the lance 21 toward and away from a surface of the molten metal; and a detector 22 configured to detect a parameter indicating a reaction state, in which the reactant gas and the molten metal react with each other in a striking region where the reactant gas blown from the lance 21 toward the surface of the molten metal strikes on the surface of the molten metal. The lance 21 is configured so as to be positioned to an adequate position on the basis of a value of the parameter indicating the reaction state.

Description

  The present invention relates to a lance facility used in a refining furnace such as an electric furnace or a converter, a refining furnace using the same, and a lance position adjusting method.

  2. Description of the Related Art A smelting furnace used for refining metal materials such as steel materials, for example, an electric furnace, is provided with a lance for spraying a reaction gas such as oxygen gas on the surface of molten metal in the furnace. Such a lance can be moved up and down by an elevating drive mechanism so as to have an appropriate height according to the molten metal surface (for example, Patent Document 1). In the field of converters, a method of using a microwave to determine the distance between the lance and the molten metal surface has been proposed (Patent Document 2).

Japanese Patent Application Laid-Open No. 8-17639 JP 2009-97035 A

  However, during operation of the electric furnace, it is often difficult to grasp the position of the molten metal surface due to the presence of a large amount of slag on the molten metal surface. Therefore, when there is a large amount of slag, conventionally, a method such as determining the height of the molten metal surface from the amount of the solid metal material to be supplied and determining the tip position of the lance based on it is used. It was. However, the detection accuracy of the molten metal surface height is not necessarily high, and the tip position of the lance may not be maintained at an appropriate position. Further, the appropriate distance itself between the molten metal surface and the tip of the lance itself has been empirically obtained in repeated operations, and may not necessarily be appropriate in terms of reaction. Therefore, even if the height of the molten metal surface, that is, the distance between the lance and the molten metal surface is accurately determined, whether or not the position of the lance with respect to the molten metal surface is optimal from the viewpoint of the chemical reaction depends on the molten metal and the reaction. Depending on the nature of the gas, blowing conditions, etc., it has been difficult to keep the reaction state between the molten metal and the reaction gas within a certain range. In particular, in the case of an electric furnace that continuously melts a solid metal material, the height of the molten metal surface changes with time, making it more difficult to keep the tip position of the lance at an appropriate position. .

  The present invention has been made in view of such circumstances, and is a lance facility capable of setting the lance for injecting the reaction gas to an appropriate position regardless of the absolute position of the molten metal surface in the refining furnace. And a refining furnace using the same, and a lance position adjusting method.

  In order to solve the above problems, the lance facility according to the first aspect of the present invention is a lance facility for injecting a reaction gas into molten metal in a smelting furnace for refining metal, and a lance for injecting the reaction gas; A drive mechanism for moving the lance forward and backward with respect to the molten metal surface, and a reaction state between the reaction gas and the molten metal in a collision region where the reaction gas injected from the lance collides with the molten metal surface And a detector that detects a parameter indicating the reaction state, and the lance can be adjusted to an appropriate position based on the value of the parameter indicating the reaction state supplied from the detector.

  The lance facility according to the first aspect preferably further includes a control unit configured to control the drive mechanism based on the value of the parameter and adjust the lance to an appropriate position. In addition, the control unit specifies a change position that is the position of the lance where the reaction state suddenly changes from a change curve of the parameter value with respect to the position of the lance, and determines the lance based on the information on the change position. It is preferable to be configured to adjust to the appropriate position.

  The said lance installation WHEREIN: The said detector can be set as the structure which has an optical fiber which detects the light of the said collision area | region, and a measurement part which measures the said parameter based on the information from the said optical fiber. It is preferable that the optical fiber is inserted into a reaction gas flow hole provided in the lance. Moreover, it is preferable that the said measurement part is provided in the base end part of the said lance.

  The detector may include a camera that captures the collision area. The camera can be provided at the proximal end of the lance.

  The detector may be provided at a position away from the lance. The parameter in the collision region may be selected from a molten metal temperature, light intensity, light spectrum, and specific wavelength intensity. Examples of the reaction gas include oxygen gas.

  The smelting furnace according to the second aspect of the present invention is a smelting furnace for smelting metal, and a container for storing molten metal, and a reactive gas is blown into the molten metal in the container. Lance equipment.

  As the smelting furnace, an electric furnace that melts a solid metal material by an arc can be used, and particularly suitable for an electric furnace in which the solid metal material is continuously supplied to the melting chamber and the solid metal material is continuously melted. is there.

  A lance position adjusting method according to a third aspect of the present invention is a lance position adjusting method for adjusting a position of a lance for injecting a reaction gas into a molten metal in a smelting furnace for refining metal, wherein the reaction gas is injected. The lance is brought close to the molten metal surface, the parameter indicating the reaction state between the reaction gas and the molten metal in the collision region where the reaction gas collides with the molten metal surface, the parameter indicating the reaction state Adjusting the lance to an appropriate position based on the value of.

  In the lance position adjustment method, a change position that is the position of the lance at which the reaction state suddenly changes is specified from a change curve of the parameter value with respect to the lance position, and the lance position is determined based on the change position information. It is preferable to further include adjusting the position to the proper position.

  In the present invention, the reaction gas is blown from the lance to the molten metal surface, the parameter indicating the reaction state between the reaction gas and the molten metal in the collision region of the molten metal surface is detected, and the value greatly changes in the vicinity of the proper blowing position of the lance. To determine the appropriate position of the lance when the reactive gas is blown. For this reason, the position of a lance can always be made into an appropriate position irrespective of the absolute position (height) of a molten steel surface. In addition, since a parameter indicating the reaction state between the reaction gas and the molten metal is used, the position of the lance where the reaction gas can be blown so that the reaction gas actually reacts with the molten metal is determined from the value of the parameter. And the reactivity can be improved.

It is sectional drawing which shows the electric furnace (arc furnace) as a refining furnace to which the lance installation which concerns on one Embodiment of this invention is applied. It is sectional drawing which shows the structure of the lance of the lance installation which concerns on one Embodiment of this invention. It is a schematic diagram which shows the operation | movement state of a lance, (a) The state which started oxygen blowing in the retreat position (situation 1), (b) The state which lowered | lowered the lance while blowing oxygen (situation 2), (c ) The position (situation 3) at which the temperature of the collision area of the molten steel surface becomes a fire point is shown. It is a figure which shows the relationship between the lance position in the conditions 1-3 of FIG. 3, and the temperature of a collision area | region. It is sectional drawing which shows the lance installation which concerns on other embodiment of this invention. It is sectional drawing which shows the lance installation which concerns on further another embodiment of this invention.

Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.
In the present embodiment, the present invention is applied to an electric furnace (arc furnace) in which a cold iron source such as iron scrap is used as a solid metal material, which is continuously supplied to a melting furnace and heated and melted by an arc electrode. Show the case.

  FIG. 1 is a cross-sectional view showing an electric furnace (arc furnace) as a refining furnace to which a lance facility according to an embodiment of the present invention is applied. The electric furnace 1 includes a melting chamber 2 for arc melting of a cold iron source such as iron scrap, and a shaft type preheating chamber 3 directly connected to a part of the upper portion of the melting chamber 2 for preheating the cold iron source. I have. The melting chamber 2 is lined with a refractory inside the iron skin, and the iron skin of the preheating chamber 3 is water-cooled.

  An openable / closable furnace lid 4 is provided at a portion other than the preheating chamber 3 above the melting chamber 2, and three electrodes 5 are vertically passed through the furnace lid 4 from the upper side to the inside of the melting chamber 2. Has been inserted. The molten steel 8 is heated by an arc formed by applying an AC voltage to the electrode 5 from a power source (not shown), and the cold iron source 7 in the melting chamber 2 is preheated and melted to become the molten steel 8. . A slag 9 is formed on the molten steel 8, and an arc is formed in the slag 9. In addition, the bottom part of the melting chamber 2 is provided with a steel outlet (not shown).

  A supply port 10 for supplying the cold iron source 7 is provided at the upper end of the preheating chamber 3, and an opening / closing lid 11 is provided inside the supply port. And the cold iron source 7 is supplied in the preheating chamber 3 through the supply port 10 from a cold iron source supply apparatus (not shown). Further, an exhaust part 12 connected to an exhaust gas suction system (not shown) is provided in the upper part of the preheating chamber 3.

  The electric furnace 1 of the present embodiment further blows oxygen gas as a reaction gas from above the molten steel 8 in the melting chamber 2 to perform refining such as decarburization or to assist melting of the cold iron source. The lance facility 20 is provided. The lance facility 20 includes a lance 21 for injecting oxygen gas as an oxygen jet, and parameters indicating a reaction state between oxygen and molten steel in a collision region where the oxygen jet injected from the lance 21 toward the molten steel surface collides with the molten steel surface. From the detector 22 to be detected, a position sensor 23 for detecting the position of the tip of the lance 21 with respect to a fixed point in the electric furnace 1, a cylinder mechanism 24 as a drive mechanism for driving the lance 21, the detector 22 and the position sensor 23 And a control unit 25 that determines the appropriate position of the lance 21 and controls the position of the lance 21 based on the above information.

  Here, the parameter indicating the reaction state between oxygen and molten steel in the collision region is a value that changes depending on the reaction state when components in the molten steel, such as carbon, react with oxygen when oxygen is blown into the molten steel. For example, the temperature in the collision region, the light intensity, the light spectrum, the intensity of a specific wavelength, and the like can be used.

  In addition to the lance facility 20, a lance facility for blowing in carbon material as an auxiliary heat source may be provided separately. As the position sensor 23, a stroke sensor, an optical position sensor, or the like can be used. Furthermore, the drive mechanism for driving the lance 21 is not limited to the cylinder mechanism 24, and other devices such as a gear motor can be used.

  The lance 21 is disposed obliquely with respect to the molten steel surface, and is supported by the cylinder portion of the cylinder mechanism 24 by the support portion 26. By driving the cylinder mechanism 24, the molten steel surface along the guide member (not shown). It is possible to move forward and backward.

  As shown in FIG. 2, the lance 21 has an oxygen gas flow hole 31 inside, and an oxygen jet is injected from the injection port 32 at the tip of the oxygen jet onto the molten steel surface. The detector 22 is inserted into the oxygen gas flow hole 31 of the lance 21, the tip extends to a position near the molten steel surface near the injection port 32, and detects light in a collision area where the oxygen jet collides with the molten steel surface. An optical fiber 27 and a measuring unit 28 connected to the optical fiber 27 and measuring a parameter indicating a reaction state between oxygen and molten steel in the collision region based on information from the optical fiber 27 are provided. The measuring unit 28 is attached to the proximal end portion of the lance 21.

  The detector 22 constitutes, for example, an optical fiber radiation thermometer. In this case, the parameter indicating the reaction state between the oxygen gas and the molten steel in the collision region of the oxygen jet is the temperature of the collision region. Specifically, the light emitted from the collision region of the oxygen jet is detected by the optical fiber 27, and the temperature of the collision region is measured from the radiation intensity of the light in the measuring unit 28.

  The reaction state between the oxygen gas and the molten steel changes depending on the distance between the injection port 32 of the lance 21 and the collision region of the molten steel surface, and the lance 21 starts to blow oxygen as shown in FIG. When the injection port 32 of the lance 21 approaches the molten steel surface while blowing oxygen from the position retracted upward (situation 1), as shown in FIG. 3 (b), the reaction in the collision region 33 occurs. The value of the parameter indicating the state increases, and as shown in FIG. 3C, when the distance between the injection port 32 and the collision area is further reduced, the temperature of the collision area 33 is set to a fire point (temperature: 2200 ° C., for example). ) (Situation 3). And when the position of the lance 21 is in the vicinity of the position where the situation 3 is reached, it is considered that the oxygen can be blown so that oxygen can react efficiently with the molten steel 8.

  The change in the parameter indicating the reaction state in the collision area 33 at this time, for example, the change in the temperature in the collision area 33 is as shown in FIG. That is, when the lance is brought closer to the molten steel surface while oxygen is being blown in, the temperature in the collision region 33 rapidly rises at a certain point, and then the temperature is saturated when the fire point is reached. Therefore, the appropriate position of the lance 21 where oxygen can be blown in a state where the reaction efficiency is good can be determined from this temperature change. Note that the temperature change curve shown in FIG. 4 shifts to the left and right depending on the oxygen injection amount, but the change mode itself hardly changes depending on the oxygen injection amount.

  Therefore, when oxygen is blown into the molten steel surface to cause a reaction based on the temperature change as shown in FIG. 4, the proper position of the lance 21 can be determined without being influenced by the amount of oxygen injected.

  When using the intensity of light, the spectrum of light, the intensity of a specific wavelength, and the like as parameters representing the reaction state between oxygen and molten steel in the collision region where the oxygen jet collides with the molten steel surface, What is suitable for these parameters may be used.

Next, operation | movement of the electric furnace 1 comprised in this way is demonstrated.
First, a cold iron source 7 such as iron scrap is charged into the melting chamber 2 and the preheating chamber 3 so that the cold iron source 7 is continuously present in the melting chamber 2 and the preheating chamber 3.

In this state, an electric current is applied between the electrode 5 and the cold iron source 7 in the melting chamber 2 to form an arc, and the cold iron source 7 is melted. When melting of the cold iron source 7 in the melting chamber 2 has progressed and a certain amount of molten steel has been formed in the melting chamber 2, the lance 21 is used for refining such as decarburization and assisting the melting of the cold iron source. Oxygen is blown into the molten steel 8 surface. At this time, oxygen and carbon in the molten steel react to generate CO, CO _{2 and the} like. The gas generated in this way is discharged via the preheating chamber 3 and the exhaust part 12, and the cold iron source 7 in the preheating chamber 3 is preheated by the heat of the exhaust gas. When the cold iron source 7 is melted in the melting chamber 2, the cold iron source 7 in the preheating chamber 3 is supplied to the melting chamber 2, and the cold iron source 7 can be continuously melted in the melting chamber 2.

  When the cold iron source 7 in the preheating chamber 3 is supplied to the melting chamber 2, the upper end position of the cold iron source 7 in the preheating chamber 3 is lowered, so that the cold iron source 7 is connected to the melting chamber 2 and the preheating chamber 3. The cold iron source 7 is continuously or intermittently supplied from the supply port 10 to the preheating chamber 3 so as to maintain a continuous state.

  Although the lance 21 needs to be adjusted to an appropriate height according to the molten steel surface, during operation of the electric furnace 1, the absolute position (height of the molten steel surface) due to the presence of a large amount of slag on the molten steel surface. ) May be difficult to determine. In such a case, conventionally, a method such as determining the height of the molten steel surface from the amount of cold iron source to be supplied and determining the tip position of the lance based on it is used. It may not be kept in the proper position. Moreover, in the electric furnace 1 of the type that continuously melts the cold iron source as in the present embodiment, the height of the molten steel surface (molten steel level) changes with time, so the tip position of the lance is kept at an appropriate position. It becomes even more difficult.

  Therefore, in the present embodiment, when oxygen is blown from the lance 21 and the molten steel surface is exposed, a parameter indicating the reaction state between oxygen and molten steel in the collision region where the oxygen jet collides with the molten steel surface is detected. The proper position of 21 is obtained. Specifically, oxygen injection is started at the position where the lance 21 is retracted upward as shown in FIG. 3A (situation 1), and the lance 21 is lowered while oxygen is being injected as shown in FIG. 3B. Let them move closer to the molten steel surface (Situation 2) If it does so, the parameter which shows the reaction state of oxygen and molten steel in the collision area | region 33, for example, the temperature in the collision area | region 33 will rise rapidly as shown in FIG. After that, as shown in FIG. 3C, the position (fire point position; situation 3) where the distance between the injection port 32 and the collision region 33 is further shortened and the temperature of the collision region reaches the fire point (temperature: 2200 ° C.). ), The temperature in the collision region 33 is saturated as shown in FIG. When the position of the lance 21 is in the vicinity of the hot spot position, it is considered to be an appropriate position where oxygen can be blown so that oxygen can efficiently react with the molten steel 8. The position of the lance at the time when it is detected from the change curve of the parameter value that the temperature of the collision region 33 has reached the temperature near the fire point, or when the temperature change at the temperature near the fire point is detected. The position is specified, and the lance 21 is adjusted to an appropriate position based on the information on the changed position. It should be noted that the position of the lance 21 can be similarly determined using parameters other than temperature, such as light intensity, light spectrum, and specific wavelength intensity in the collision region.

  Since the electric furnace 1 is a type that continuously melts the cold iron source, the level of the molten steel surface increases with time. However, since the rising speed of the molten steel surface can be calculated according to the operating conditions, it can be dealt with by raising the lance 21 at a predetermined increasing speed obtained from the operating conditions by a command from the control unit 25. As a result, even when the level of the molten steel surface rises during oxygen blowing, oxygen can be blown in a state where the distance between the tip of the lance 21 and the molten steel surface is kept constant and the reaction efficiency is good. .

  Further, after detecting the value of a parameter such as temperature in the collision region or its change and determining the position of the lance 21 as described above, the detection of the value of that parameter or its change is continued, and the detected value is always The position of the lance 21 may be feedback controlled so as to be appropriate. In this case, when the level of the molten steel surface rises during the oxygen blowing, oxygen can be blown in a state where the distance between the tip of the lance 21 and the molten steel surface is kept constant and the reaction efficiency is good. it can.

  In the present embodiment, when the cold iron source 7 is continuously melted in this way and a predetermined amount (for example, one charge) of molten steel has accumulated in the melting chamber 2, the melting chamber 2 and the preheating chamber 3 In addition, while maintaining the state where the cold iron source 7 is continuously present, the melting chamber 2 is tilted to take the molten steel from a steel outlet (not shown) into a ladle or the like.

  Since the level of the molten steel surface of the molten steel remaining after the steel is discharged, it is preferable to perform the alignment of the lance 21 again using the parameters indicating the reaction state as described above.

  As described above, in the present embodiment, oxygen is blown from the lance 21 to the molten steel surface, the parameter indicating the reaction state between oxygen and molten steel in the collision region of the molten steel surface is detected, and the value is in the vicinity of the proper blowing position of the lance. The appropriate position of the lance 21 when oxygen is blown is obtained by utilizing the large change. For this reason, the position of the lance 21 can always be set to an appropriate position regardless of the absolute position (height) of the molten steel surface. In addition, since a parameter indicating the reaction state between oxygen and molten steel is used, the position of the lance where oxygen can be blown in a state where the reaction efficiency is actually good can be determined from the value of the parameter. It becomes possible to improve the reactivity.

  In the present embodiment, the cold iron source 7 is supplied to the preheating chamber 3 so that the cold iron source 7 is always present continuously in the melting chamber 2 and the preheating chamber 3. When the molten steel is formed and the steel is discharged, the cold iron source is continuously present in the melting chamber 2 and the preheating chamber 3, so that the preheating efficiency of the cold iron source by the exhaust gas is high.

The present invention can be variously modified without being limited to the above embodiment.
For example, in the above embodiment, the detector has an optical fiber whose tip extends to a position near the molten steel surface near the injection port and a measurement unit that measures a parameter indicating a reaction state, but is not limited thereto. For example, as shown in FIG. 5, a camera 34 capable of photographing the collision region of the oxygen jet as a detector is provided at the base end portion of the lance 21, and the collision region of the oxygen jet is detected through the oxygen gas flow hole 31. You may shoot. Of course, you may use an optical fiber and a camera together.

  Moreover, in the said embodiment, although the example which attached the detector to the lance 21 was shown, it is not limited to this, For example, as shown in FIG. You may provide the detector 36 which detects the parameter of the collision area | region 33 which collided with.

  Furthermore, in the said embodiment, although the example which used steel as a metal material and used oxygen gas as a reactive gas was shown, a metal material and a reactive gas are not restricted to these. In the above embodiment, an electric furnace of a type that continuously melts a cold iron source, which is a solid metal material, is illustrated as a refining furnace. However, a normal electric furnace may be used, and a refining process may be performed by blowing a reaction gas. If it does, it is applicable not only to an electric furnace but various things, such as a converter, a VOD (Vacuum Oxygen Decarburization) furnace, an RH degassing furnace for carrying out the RH-OB method, etc., for example.

  Furthermore, the operation for obtaining the appropriate position of the lance by detecting the parameter indicating the reaction state such as the temperature of the collision region is not limited to the timing of the above embodiment, and may be performed as necessary.

1: Electric furnace (smelting furnace)
2; Melting chamber 3; Preheating chamber 4; Furnace 5; Electrode 7; Cold iron source 8; Molten steel 9; Slag 10; Supply port 20; Lance equipment 21; Lance 22, 36; Mechanism 25; Control unit 27; Optical fiber 28; Measurement unit 31; Oxygen gas flow hole 32; Injection port 33;

Claims (16)

In a smelting furnace for refining metal, a lance facility for injecting reaction gas into molten metal,
A lance for injecting the reaction gas;
A drive mechanism for moving the lance forward and backward with respect to the molten metal surface;
A detector for detecting a parameter indicating a reaction state between the reaction gas and the molten metal in a collision region where the reaction gas injected from the lance onto the molten metal surface collides with the molten metal surface;
Have
A lance facility characterized in that the lance can be adjusted to an appropriate position based on a parameter value indicating the reaction state supplied from the detector.   The lance facility according to claim 1, further comprising a control unit configured to control the drive mechanism based on the value of the parameter and adjust the lance to an appropriate position.   The control unit identifies a change position, which is the position of the lance where the reaction state suddenly changes, from a change curve of the parameter value with respect to the position of the lance, and determines the appropriate lance based on the information on the change position. The lance facility according to claim 2, wherein the lance facility is configured to adjust to a position.   The said detector has an optical fiber which detects the light of the said collision area | region, and the measurement part which measures the said parameter based on the information from the said optical fiber, The any one of Claim 1 to 3 characterized by the above-mentioned. The lance equipment according to item 1.   The lance equipment according to claim 4, wherein the optical fiber is inserted into a reaction gas flow hole provided in the lance.   The lance facility according to claim 4 or 5, wherein the measuring unit is provided at a proximal end portion of the lance.   The lance facility according to any one of claims 1 to 3, wherein the detector includes a camera that photographs the collision area.   The lance equipment according to claim 7, wherein the camera is provided at a base end portion of the lance.   The lance facility according to any one of claims 1 to 3, wherein the detector is provided at a position away from the lance.   The said parameter in the said collision area | region is selected from the temperature of molten metal, the intensity | strength of light, the spectrum of light, and the intensity | strength of a specific wavelength, The any one of Claims 1-9 characterized by the above-mentioned. Lance equipment as described in   The lance facility according to any one of claims 1 to 10, wherein the reaction gas is oxygen gas. A refining furnace for refining metals,
A container for storing molten metal;
A smelting furnace comprising the lance facility according to any one of claims 1 to 11, wherein a reactive gas is blown into the molten metal in the vessel.   The smelting furnace according to claim 12, wherein the smelting furnace is an electric furnace that melts a solid metal material by an arc.   The smelting furnace according to claim 13, wherein the smelting furnace is an electric furnace in which the solid metal material is continuously supplied to the melting chamber and the solid metal material is continuously melted. In a refining furnace for refining metal, a lance position adjusting method for adjusting a position of a lance for injecting a reaction gas into molten metal,
Bringing the lance closer to the molten metal surface while injecting the reactive gas;
Detecting a parameter indicating a reaction state between the reaction gas and the molten metal in a collision region where the reaction gas collides with the molten metal surface,
Adjusting the lance to an appropriate position based on a parameter value indicating the reaction state. Identifying a change position that is the position of the lance where the reaction state suddenly changes from a change curve of the value of the parameter with respect to the position of the lance;
The lance position adjusting method according to claim 15, further comprising adjusting the lance to the proper position based on information on the change position.

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