JP2009097035A - Method for controlling position of lance, and lance device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lance device which can precisely measure a distance between a lance and a liquid surface of molten pig iron even while a treatment gas is sprayed, and can improve reaction characteristics with the treatment gas. <P>SOLUTION: The method for controlling the position of the lance includes detecting the distance between the lance and the liquid surface of the molten metal by using a microwave rangefinder that is installed in the lance and controlling the position of the lance on the basis of information on the detected position. The lance device includes the lance having a spouting port for spraying the treatment gas onto the molten metal in a furnace, and the microwave rangefinder which is installed in the lance and measures the distance between the lance and the surface of the molten metal. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to, for example, a lance device used in a converter facility in a steel mill of an ironworks, and a position control method thereof.

  In converter equipment, a lance is used to perform decarburization, desulfurization, dephosphorization, and the like by blowing gas onto hot metal or molten steel in an iron processing process (see, for example, Patent Document 1).

  For example, in a top blow converter, a high-speed pure oxygen jet is sprayed onto the hot metal from an injection port provided on the lower surface of the lance, and the blown oxygen and carbon in the hot metal are directly reacted to decarburize as carbon monoxide. At that time, in order to arrange the lance at the optimum position, the distance from the injection port on the lower surface of the lance to the hot metal surface is measured using a microwave distance meter.

  FIG. 1 is a cross-sectional view schematically showing an example of a conventional top blow converter. The microwave rangefinder 11 is attached to a robot arm 12 installed at an appropriate position above the converter 16. At the time of distance measurement, the lance 10 is positioned at the uppermost part on the extension line of the lance hole 13. When a measurement start signal is given to the robot arm 12 in the starting position, the robot arm 12 turns to move the antenna 113 of the microwave rangefinder 11 directly above the lance hole 13. The microwave oscillated by the controller 112 becomes a microwave beam 14 from the antenna 113 and is transmitted into the converter 16. Then, the microwave beam 14 reflected by the molten metal surface 15 is received by the antenna 113 and returns to the controller 112. The controller 112 calculates and outputs the distance from the antenna 112 to the liquid surface 15 on the hot metal or slag surface based on the time from transmission to reception of the microwave. After the distance measurement, the robot arm 12 returns to the starting position, and then the lance 10 is lowered by a predetermined amount through the lance hole 13 based on the measured distance information, and the spraying operation is started.

JP-A-10-140224

  In the top blowing converter, during the spraying, the liquid level 15 of the hot metal is greatly recessed, and the entire liquid surface including the recessed portion is undulated (see FIG. 2). However, in the above method, since the distance between the lance 10 and the molten metal surface 15 is only measured once before the spraying operation, the distance between the spray port of the lance 10 being sprayed and the molten metal surface 15 is It is unknown and there is a possibility that the reaction between oxygen and carbon is not sufficiently performed.

  In addition, since slag is floating on the liquid surface 15 of the hot metal, it is difficult to measure the distance to the liquid surface 15 of the hot metal when spraying is stopped.

  The present invention solves the above-described problems, and provides a lance device that can accurately measure the distance between the lance and the liquid level of the molten iron even during the spraying of the processing gas and improve the reaction characteristics with the processing gas. For the purpose.

In order to achieve the above object, the present invention provides the following lance device.
(1) A method for controlling the position of a lance for blowing a processing gas on a molten metal in a melting furnace,
A lance position in which a microwave distance meter is incorporated in the lance, the distance between the lance and the liquid surface of the molten metal is detected by the microwave distance meter, and the position of the lance is controlled based on the detected position information. Control method.
(2) A lance having an injection port for spraying a processing gas onto the molten metal in the furnace, and a microwave rangefinder incorporated in the lance and measuring a distance from the lance to the surface of the molten metal Lance device characterized by that.
(3) The lance device according to (2), wherein an antenna of the microwave rangefinder is provided on the lower surface of the lance.
(4) The lance device according to (2) or (3) above, wherein a controller including a microwave transmitter / receiver of a microwave rangefinder is attached to the inside or upper part of the lance.
(5) The lance device according to (4), wherein the antenna and the controller are connected by a waveguide.
(6) The waveguide is more than the first waveguide connected to the microwave transceiver, the second waveguide connected to the antenna, and the first waveguide and the second waveguide. The above (5), characterized by comprising a third waveguide having a large diameter and connected to each of the first waveguide and the second waveguide via a tapered tube. Lance device.
(7) The lance device according to (6) above, wherein a gas flow passage for supplying a processing gas from the outside and blowing it out from the injection port is formed so as to surround the waveguide.
(8) The lance device according to (7), wherein the waveguide has a vent hole, and a processing gas flowing through the gas flow path through the vent hole is caused to flow into the waveguide and ejected from the antenna.
(9) The lance device according to (4), wherein the antenna and the controller are connected by a coaxial cable.
(10) The antenna includes a waveguide connected to the antenna and formed with a vent hole, and a gas flow path for supplying a processing gas from the outside and blowing it out from the injection port surrounds the waveguide. The lance device as set forth in (9), wherein the processing gas flowing through the gas flow passage through the vent hole flows into the waveguide and is ejected from the antenna.
(11) The lance device according to any one of (2) to (10), wherein the position of the lance is controlled by a distance output of the microwave rangefinder.

  In the lance device of the present invention, since the antenna of the microwave rangefinder is attached to the lance, the distance to the liquid surface of the hot metal can be accurately measured even during gas blowing, and the lance can be controlled to the optimum position. In addition, by ejecting gas from the antenna, a suspended object does not adhere to the antenna and does not enter the waveguide, so that good distance measurement can be performed.

  Hereinafter, the present invention will be described with reference to the drawings.

  FIG. 2 is a cross-sectional view schematically showing a state in which decarburization processing is performed in a top blow converter using a lance device incorporating the microwave distance meter of the present invention.

  The lance device is lowered toward the converter 29 through the lance hole 23. The lance 22 has a gas injection port 25 formed on the lower surface facing the converter 29, and a controller 21 having a microwave transmission / reception function and a calculation function is attached to the upper part on the opposite side. Since the controller 21 is located outside the converter 29 and is placed at room temperature, it is not affected by heat.

  Further, the microwave oscillated from the microwave oscillator (not shown) of the controller 21 propagates through a waveguide (see FIG. 3) or a coaxial cable (see FIG. 4) passing through the housing of the lance 22, and the lance 22. Is transmitted from the antenna 24 attached to the center of the lower surface of the steel sheet toward the liquid surface 28 of the hot metal (microwave beam 26). The microwave beam 26 transmitted from the antenna 24 is reflected by the molten metal surface 28 and received by the antenna 24, propagates through a waveguide or a coaxial cable, and enters a microwave detector (not shown) of the controller 21. Is detected. The controller 21 calculates the distance between the lower surface of the lance 22 and the liquid level 28 of the hot metal based on the time from the oscillation of the microwave to the detection and outputs the distance as position information of the lance 22. Based on this position information, the descent position of the lance 22 is controlled. Note that the microwave oscillator and the microwave detector can be shared to provide a microwave transceiver.

  The liquid surface 28 of the hot metal is undulated as shown in the figure by the pure oxygen gas 27 blown from the injection port 25 of the lance 22, but according to the lance device of the present invention, the pure oxygen gas is being blown. Also, the liquid level 28 of the hot metal can be detected. Therefore, the lance 22 can always be controlled to the optimum position.

  Further, even when slag is present on the liquid surface 28 of the hot metal, since the specific gravity of the slag is smaller than that of the hot metal, the slag located immediately below the antenna can be moved to the outside by pure oxygen gas blown from the antenna 24. The microwave beam 26 is reliably transmitted to the molten metal surface 28, and accurate distance measurement can be performed.

  Alternatively, since the microwave has a property of passing through the slag, by stopping the blowing of pure oxygen gas and transmitting the microwave beam 26, a part of the microwave beam 26 is reflected by the slag surface, and the rest is the slag. The controller 21 detects the microwave beam reflected by the slag surface and the microwave beam reflected by the liquid surface 28 of the hot metal and detects the microwave beam reflected by the liquid surface 28 of the hot metal, The distance is measured, and the farther side is determined as the distance to the liquid surface 28 of the molten iron. Also, the slag thickness can be calculated by calculating the slag thickness from the difference between the distance to the surface of the slag and the distance to the liquid level 28 of the hot metal.

  FIG. 3 is a schematic diagram showing details in the lance when a waveguide is used for microwave propagation.

  Similarly to the above, the controller 31 is attached to the upper part of the lance 40, the antenna 36 is attached to the lower part of the lance 40, and an injection port is formed in the vicinity of the antenna 36. Since the controller 31 is attached to the upper portion of the lance 40, the pure oxygen gas flow passage and the cooling water flow passage, which will be described later, are not obstructed.

  A tapered tube 321 that gradually increases in diameter is connected to the microwave transceiver of the controller 31, and a large-diameter waveguide 33 is continuously connected to the tapered tube 321. A tapered tube 322 that gradually narrows is connected to the large-diameter waveguide 33, and a normal-size straight tube 35 attached to the antenna 36 is connected to the tapered tube 322. Although the microwave propagation speed changes depending on the modulation frequency and the distance measurement accuracy deteriorates, the microwave propagation speed should be the same as that in the atmosphere by the large-diameter waveguide 33 regardless of the microwave modulation frequency. It is possible to prevent a decrease in accuracy.

  Also, a large number of vent holes 34 are formed in the large-diameter waveguide 33, and a gas flow passage 37 for pure oxygen gas is formed around the large diameter waveguide 33 so that the pure oxygen gas passes through the vent holes 34 and is indicated by an arrow 41. As shown, it is also ejected from the antenna 36. Therefore, the floating object does not adhere to the antenna 36 or enter the waveguide, and the transmission / reception of the microwave beam is always improved. In addition, the arrow 42 in a figure is the pure oxygen gas ejected from a jet nozzle. The vent hole may be formed in a tapered tube.

  Further, the outside region of the gas flow passage 37 inside the lance is a cooling water flow passage for circulating the cooling water. The cooling water is introduced from the cooling water inlet 38 and circulated through the cooling water outlet, and then the cooling water outlet. Let it flow out of 39. Thereby, the lance 40 is protected from the radiant heat from the hot metal.

  FIG. 4 is a schematic diagram showing details in the lance when a coaxial cable is used for microwave propagation. The lance device shown in FIG. 3 is replaced with a waveguide 33 and tapered tubes 331 and 332. This is the same except that the coaxial cable 42 is used.

  That is, the controller 41 is attached to the upper portion of the lance 51, the antenna 47 is attached to the lower portion of the lance 51, and an injection port is formed in the vicinity of the antenna 47. A coaxial cable 42 is connected to the microwave transceiver of the controller 51. The coaxial cable 42 is inserted through a coaxial cable protection pipe 43 disposed along the axis of the gas flow passage 48. The other end of the coaxial cable 42 is connected via a coaxial waveguide converter 44 to a perforated waveguide 45 in which a large number of ventilation holes are formed. A wave tube 46 is connected. The pure oxygen gas supplied to the gas flow passage 48 is also ejected from the antenna 47 as indicated by the arrow 52 through the vent hole of the perforated waveguide 45. In addition, the arrow 53 in a figure is the pure oxygen gas ejected from a jet nozzle. Further, cooling water flows from the cooling water inlet 49, circulates inside the lance, flows out of the cooling water outlet 50, and cools the lance 40.

  The microwave used for transmission and reception in the lance device of the present invention may be a straight wave directed in one direction with an electric field distribution, but a rotating wave whose electric field distribution rotates clockwise or counterclockwise is used. Is preferred. Rotational waves have the property of reversing the direction of rotation each time they are reflected. Therefore, the microwaves reflected by the hot metal surface (rotational waves) and the microwaves reflected by the hot metal surface and further reflected by other members (Rotational wave) can be clearly distinguished, and the measurement accuracy is greatly increased. In order to obtain a rotating wave, a known method such as using a circular polarizer can be used.

It is sectional drawing which shows an example of the conventional top blow converter. It is sectional drawing which shows an example of the top blowing converter provided with the lance apparatus of this invention. It is sectional drawing which shows the other example of a lance. It is sectional drawing which shows the further another example of a lance.

Explanation of symbols

21 Controller 22 Lance 24 Antenna 25 Injection Port 28 Molten Liquid Level 29 Converter 33 Waveguides 321 and 322 Tapered Tube 42 Coaxial Cable

Claims (11)

A method for controlling a position of a lance for blowing a processing gas to a molten metal in a melting furnace,
A lance position in which a microwave distance meter is incorporated in the lance, the distance between the lance and the liquid surface of the molten metal is detected by the microwave distance meter, and the position of the lance is controlled based on the detected position information. Control method.   A lance having an injection port for spraying a processing gas to the molten metal in the furnace, and a microwave distance meter incorporated in the lance and measuring a distance from the lance to the surface of the molten metal Lance device.   The lance device according to claim 2, wherein an antenna of the microwave rangefinder is provided on a lower surface of the lance.   4. The lance device according to claim 2, wherein a controller including a microwave transmitter / receiver of the microwave rangefinder is attached to the inside or upper part of the lance.   The lance device according to claim 4, wherein the antenna and the controller are connected by a waveguide.   The waveguide is larger in diameter than the first waveguide connected to the microwave transceiver, the second waveguide connected to the antenna, and the first waveguide and the second waveguide. And a third waveguide connected to each of the first waveguide and the second waveguide via a tapered tube.   The lance device according to claim 6, wherein a gas flow passage for supplying the processing gas from the outside and blowing it out from the injection port is formed so as to surround the waveguide.   8. The lance device according to claim 7, wherein the waveguide has a vent hole, and a processing gas flowing through the gas flow passage through the vent hole is introduced into the waveguide and ejected from the antenna.   The lance device according to claim 4, wherein the antenna and the controller are connected by a coaxial cable.   An antenna is connected to the antenna and includes a waveguide having a vent hole, and a gas flow path for supplying a processing gas from the outside and blowing it out from the injection port is formed surrounding the waveguide. 10. The lance device according to claim 9, wherein the processing gas flowing through the gas flow passage through the vent hole flows into the waveguide and is ejected from the antenna.   The lance device according to any one of claims 2 to 10, wherein the position of the lance is controlled by a distance output of the microwave rangefinder.

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