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WO2010142407A1 - Method for operating a bottom purging system of a bof converter - Google Patents

Method for operating a bottom purging system of a bof converter Download PDF

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Publication number
WO2010142407A1
WO2010142407A1 PCT/EP2010/003411 EP2010003411W WO2010142407A1 WO 2010142407 A1 WO2010142407 A1 WO 2010142407A1 EP 2010003411 W EP2010003411 W EP 2010003411W WO 2010142407 A1 WO2010142407 A1 WO 2010142407A1
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WO
WIPO (PCT)
Prior art keywords
gas
converter
inert gas
annular gap
central tube
Prior art date
Legal status (The legal status 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 status listed.)
Ceased
Application number
PCT/EP2010/003411
Other languages
German (de)
French (fr)
Inventor
Lutz Rose
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
SMS Siemag AG
Original Assignee
SMS Siemag AG
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Filing date
Publication date
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Application filed by SMS Siemag AG filed Critical SMS Siemag AG
Priority to EP10723541A priority Critical patent/EP2440872B1/en
Publication of WO2010142407A1 publication Critical patent/WO2010142407A1/en
Anticipated expiration legal-status Critical
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Classifications

    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21CPROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C5/00Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
    • C21C5/28Manufacture of steel in the converter
    • C21C5/30Regulating or controlling the blowing
    • C21C5/34Blowing through the bath
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21CPROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C5/00Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
    • C21C5/28Manufacture of steel in the converter
    • C21C5/42Constructional features of converters
    • C21C5/46Details or accessories
    • C21C5/48Bottoms or tuyéres of converters
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27FURNACES; KILNS; OVENS; RETORTS
    • F27DDETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D1/00Casings; Linings; Walls; Roofs
    • F27D1/16Making or repairing linings ; Increasing the durability of linings; Breaking away linings
    • F27D1/1678Increasing the durability of linings; Means for protecting
    • F27D1/1684Increasing the durability of linings; Means for protecting by a special coating applied to the lining
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27FURNACES; KILNS; OVENS; RETORTS
    • F27DDETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D3/00Charging; Discharging; Manipulation of charge
    • F27D3/16Introducing a fluid jet or current into the charge
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27FURNACES; KILNS; OVENS; RETORTS
    • F27DDETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D3/00Charging; Discharging; Manipulation of charge
    • F27D3/16Introducing a fluid jet or current into the charge
    • F27D2003/162Introducing a fluid jet or current into the charge the fluid being an oxidant or a fuel
    • F27D2003/163Introducing a fluid jet or current into the charge the fluid being an oxidant or a fuel the fluid being an oxidant
    • F27D2003/164Oxygen
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27FURNACES; KILNS; OVENS; RETORTS
    • F27DDETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D3/00Charging; Discharging; Manipulation of charge
    • F27D3/16Introducing a fluid jet or current into the charge
    • F27D2003/162Introducing a fluid jet or current into the charge the fluid being an oxidant or a fuel
    • F27D2003/165Introducing a fluid jet or current into the charge the fluid being an oxidant or a fuel the fluid being a fuel
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27FURNACES; KILNS; OVENS; RETORTS
    • F27DDETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D3/00Charging; Discharging; Manipulation of charge
    • F27D3/16Introducing a fluid jet or current into the charge
    • F27D2003/166Introducing a fluid jet or current into the charge the fluid being a treatment gas
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27FURNACES; KILNS; OVENS; RETORTS
    • F27DDETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D3/00Charging; Discharging; Manipulation of charge
    • F27D3/16Introducing a fluid jet or current into the charge
    • F27D2003/167Introducing a fluid jet or current into the charge the fluid being a neutral gas

Definitions

  • the invention relates to a method for operating in a distributed arrangement of a plurality of central tube and an outer tube existing annular gap nozzles having soil flushing system of a BOF converter with inert gas blowing for decarburization of the melt in the converter.
  • EP 1 641 946 B1 is in connection with Aufblas vide in the production of alloyed metal melts or when refining pig iron in a converter for supporting soil injection of various energy sources, alloying agents, charring and decarburizing or the like from a central tube and at least one concentric annular channel existing Annular gap nozzles have become known.
  • hydrocarbon is blown through the annular gap in all process steps.
  • the blowing rate is 0.25 to 3.5 Nm 3 / tx min. And requires large amounts of gas.
  • the flushing blocks or blocks consist of a refractory, such as ceramic material.
  • the purging blocks or blocks are in turn interspersed with nozzles to introduce the inert gas in the metal melt in the converter.
  • the gas flows through the converter nozzles under high pressure and at high speed and enters the molten metal from below in the area of the converter base.
  • CONFIRMATION COPY Badzi achieved, which compensates, among other things, temperature differences in the molten bath.
  • the nozzles thus operate under harsh conditions, especially at their discharge end, which is permanently in contact with the molten metal. Accordingly, the nozzle is subject to high wear.
  • the burn-up or premature wear of the nozzles at their feed end is, according to experience, approximately 0.25 mm per converter charge.
  • the refractory material of the purging plug or Spülblockes in the immediate vicinity of the nozzle by the high pressure and the high velocity of the injected gas also wears heavily and thereby washed out concave.
  • the durability of the bottom with the purging blocks or blocks and the nozzles is based on the example of a 330t BOF converter in the range of about 4000 melts, whereas the durability of the likewise lined with a refractory material side walls of the converter is about 7000 melts.
  • the invention is therefore based on the object to avoid the disadvantages described above and to provide a method by which the durability of the nozzles and the purging plug or block significantly improved and thus the number of melting cycles in the converter is increased.
  • the inert gas is at least temporarily injected together with hydrocarbon and together with a through the annular gap between the central tube and the outer tube, reacted with the inert gas or gas mixture of the central tube shell gas, preferably hydrocarbon, wherein the cladding gas cleaved upon contact with the liquid steel is formed and a circular gap surrounding the annular gap, mushroom-shaped, porous steel shell.
  • the inert gas preferably argon or nitrogen, and also the hydrocarbon is injected for metallurgical treatment of the molten metal as a core jet according to the invention via the central tube or die in the molten steel, while the shell gas, in addition to hydrocarbon optionally also steam or CO 2 , as an outer ring beam blown.
  • the shell gas in addition to hydrocarbon optionally also steam or CO 2 , as an outer ring beam blown.
  • the diameter, for example up to 15 cm, and the height, for example up to 4 cm, of the mushroom-shaped, porous and circularly surrounding the nozzle steel shell can be varied.
  • the porous iron fungus thus covers, on the one hand, the flushing stone or block in the surrounding area of the nozzles, which prevents wear in the form of leaching of the refractory material.
  • the nozzles are protected by the einhausende foreclosure from burning.
  • the only used for bath movement nozzle assembly requires only small amounts of gas, which can achieve a blow rate, which is about ⁇ 0.045 Nm 3 / tx min.
  • porous iron fungus or steel jacket forms as a batch over the top of the central inert gas nozzle during the solidification of the molten metal and thus should enforce it, advantageously a small amount of oxygen can be temporarily added to the inert gas and thereby the inert gas nozzle or the central tube be burned.
  • a further embodiment of the invention provides that each annular gap nozzle is controlled individually and a constant pressure is maintained. Should there be an increase in pressure in spite of the pressure parameters previously set in the control system, whereby both the central tube and the annular gap would become clogged, a changeover to an oxygen or inert gas admixture takes place in the control system until the previously set, constant Target pressure is reached again.
  • a further advantage of the method results when the converter is operated with the so-called "slag splashing."
  • This is a known method in which the residual slag is retained in the converter after the converter has been cut off Top lance Large quantities of nitrogen are blown into the converter at high pressure and high speed, where the residual slag is sprayed to the side walls and to the bottom of the converter vessel.
  • the sprayed slag is allowed to solidify, forming a protective layer for the refractory material in the bottom and sidewalls.
  • the inventively designed in a circular manner around the annular gap, porous, also very rough iron fungus increases in this area the surface.
  • FIG. 1 is a schematic sectional view of a conventional, known in the art soil purging plug of a BOF converter
  • Fig. 2 is a schematic sectional view of a bottom spoiler of a BOF converter according to the invention, which has an annular gap nozzle arrangement for rinsing the molten steel.
  • Fig. 1 shows a known in the art soil rinse stone 1 of a BOF converter, not shown here for refining, mixing and / or rinsing a molten steel.
  • the floor scavenger 1 a pipe 2 as a nozzle, via which an inert gas 3, for example nitrogen, is blown for bath movement.
  • the nozzle / tube 2 is embedded in a monoblock 4, which consists of a refractory material, for example ceramic, which in turn is enclosed by the refractory material 5 of the lining of the converter.
  • a nozzle arrangement which consists of an annular pipe nozzle 11 made of the central pipe 2 and an outer pipe 7 enclosing this concentrically with an annular gap 8.
  • the nozzle diameter of the central tube 2 does not need to be more than 5 mm and that of the annular gap nozzle 11 not more than 1 mm.
  • Inert gas 3 and intermittently hydrocarbon are injected via the central tube 2, while hydrocarbon and / or oxygen are blown through the annular gap 8 of the annular die 11 in a mixture with inert gas as the jacket gas 9.
  • the jacket gas 9 meets with the molten steel, the hydrocarbon is split. Since this reaction requires a lot of energy, a solidification of steel in the immediate vicinity 6 of the annular gap nozzle 11 is achieved.
  • a mushroom-shaped, porous steel jacket 10 forms in a circle around the annular gap nozzles 11.
  • the porous iron fungus or steel jacket 10 prevents, on the one hand, the premature wear of the refractory material of the monobloc 4, since it lies protectively over it, and, on the other hand, a burning of the tubes 2, 7 of the annular gap nozzle 11, since it surrounds them concentrically and thus after foreclosed on the outside.
  • the porous iron fungus 10 enforces the central tube 2 of the annular gap nozzle 11, a small amount of oxygen can be added to the inert gas 3. Due to the added amount of oxygen and the associated reaction, the central tube 2 burns freely. For the annular gap 8 can also be driven an inert gas-oxygen mixture, if clogging appears. The oxygen thus serves only to control or form the size of the iron fungus 10.
  • an inert gas 3 eg Ar or N 2 , and (Ar + O 2 ) + (N 2 + O 2 ) can be driven.
  • the annular gap nozzles 11 of the converter are integrated into a control loop which on the one hand individually controls and regulates each central tube 2 and the annular gap 8 and on the other hand keeps constant the pressure with which the nozzles are acted upon. Should there nevertheless be an increase in pressure above an upper limit, the annular gap 7 and / or the central tube 2 becoming clogged, then the system is driven in the mode "oxygen / inert gas" via the control loop until the desired pressure is reached again.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Carbon Steel Or Casting Steel Manufacturing (AREA)

Abstract

The invention relates to a method for operating a bottom purging system (100) of a BOF converter, said system having, in a distributed arrangement, a plurality of annular slot nozzles (11) consisting of a central pipe (2) and an outer pipe (7), with inert gas injection for decarburizing the melt in the converter. The aim of invention is to provide a method that considerably improves the durability of the nozzles and of the purging sink or block and thus raises the number of smelting cycles in the converter. This is achieved in that, via the central pipe (2), the inert gas (3) is at least intermittently injected together with hydrocarbon and jointly with a jacket gas (9) that is fed through the gap (8) between the central pipe and the outer pipe and that reacts with the inert gas or the gas mixture from the central pipe (2), wherein the jacket gas is split upon meeting the liquid steel, and a mushroom-shaped porous steel jacket (10) that circularly encloses the annular slot nozzles (11) is formed.

Description

Verfahren zum Betreiben eines Bodenspülsystems eines BOF-Konverters Method for operating a floor flushing system of a BOF converter

Die Erfindung betrifft ein Verfahren zum Betreiben eines in verteilter Anordnung mehrere aus einem Zentralrohr und einem Außenrohr bestehende Ringspaltdüsen aufweisenden Bodenspülsystems eines BOF-Konverters mit Inertgas- Einblasung zur Entkohlung der Schmelze im Konverter.The invention relates to a method for operating in a distributed arrangement of a plurality of central tube and an outer tube existing annular gap nozzles having soil flushing system of a BOF converter with inert gas blowing for decarburization of the melt in the converter.

Das Spülen einer Schmelze, insbesondere einer Stahl- bzw. Metallschmelze, in einem BOF (Basic Oxygen Furnace)-Konverter mit Hilfe von Inertgas und am Konverterboden angeordneten, unterschiedlichsten Spülsteintypen bzw. Spülblöcken, ist ein im Stand der Technik hinlänglich bekanntes Verfahren.Flushing a melt, in particular a steel or molten metal, in a BOF (Basic Oxygen Furnace) converter with the aid of inert gas and arranged on the converter base, different types of sinks or Spülblöcken, is well-known in the art method.

Durch die EP 1 641 946 B1 ist im Zusammenhang mit Aufblasverfahren bei der Herstellung von legierten Metallschmelzen bzw. beim Frischen von Roheisen in einem Konverter zur unterstützenden Bodeneinblasung verschiedenster Energieträger, Legierungsmittel, Auf- und Entkohlungsmittel oder dergleichen aus einem Zentralrohr und mindestens einem konzentrischen Ringkanal bestehende Ringspaltdüsen bekanntgeworden. Bei diesem mehrstufigen Verfahren wird in allen Verfahrensschritten über den Ringspalt Kohlenwasserstoff eingeblasen. Die Blasrate liegt bei 0,25 bis 3,5 Nm3/t x Min. und erfordert große Gasmengen.By EP 1 641 946 B1 is in connection with Aufblasverfahren in the production of alloyed metal melts or when refining pig iron in a converter for supporting soil injection of various energy sources, alloying agents, charring and decarburizing or the like from a central tube and at least one concentric annular channel existing Annular gap nozzles have become known. In this multi-stage process, hydrocarbon is blown through the annular gap in all process steps. The blowing rate is 0.25 to 3.5 Nm 3 / tx min. And requires large amounts of gas.

Bei den gattungsgemäßen Konverter-Spülsystemen bestehen die Spülsteine bzw. -blocke aus einem feuerfesten, beispielsweise keramischen Material. Die Spülsteine bzw. -blocke sind ihrerseits mit Düsen durchsetzt, um das Inertgas in die im Konverter befindliche Metallschmelze einzubringen.In the generic converter flushing systems, the flushing blocks or blocks consist of a refractory, such as ceramic material. The purging blocks or blocks are in turn interspersed with nozzles to introduce the inert gas in the metal melt in the converter.

Dazu strömt das Gas unter hohem Druck und mit großer Geschwindigkeit durch die Konverter-Düsen und tritt im Bereich des Konverterbodens von unten her in die Metallschmelze ein. Dadurch wird in der Schmelze eine Rührwirkung bzw.For this purpose, the gas flows through the converter nozzles under high pressure and at high speed and enters the molten metal from below in the area of the converter base. As a result, in the melt a stirring effect or

BESTÄTIGUNGSKOPIE Badbewegung erreicht, die unter anderem auch Temperaturunterschiede im Schmelzbad ausgleicht.CONFIRMATION COPY Badbewegung achieved, which compensates, among other things, temperature differences in the molten bath.

Die Düsen arbeiten somit unter rauen Bedingungen, insbesondere an ihrem Einleitungsende, welches permanent in Kontakt mit dem geschmolzenen Metall steht. Dementsprechend unterliegt die Düse einem hohen Verschleiß.The nozzles thus operate under harsh conditions, especially at their discharge end, which is permanently in contact with the molten metal. Accordingly, the nozzle is subject to high wear.

Der Abbrand bzw. der voreilende Verschleiß der Düsen an ihrem Einspeisung- sende beträgt dabei erfahrungsgemäß ungefähr 0,25 mm pro Konverter- Charge.The burn-up or premature wear of the nozzles at their feed end is, according to experience, approximately 0.25 mm per converter charge.

Hinzu kommt, dass das feuerfeste Material des Spülsteins bzw. Spülblockes in unmittelbarer Umgebung der Düse durch den hohen Druck und die große Geschwindigkeit des eingeblasenen Gases ebenfalls stark verschleißt und dabei konkav ausgewaschen wird.In addition, the refractory material of the purging plug or Spülblockes in the immediate vicinity of the nozzle by the high pressure and the high velocity of the injected gas also wears heavily and thereby washed out concave.

Die Haltbarkeit des Bodens mit den Spülsteinen bzw. -blocken und den Düsen liegt am Beispiel eines 330t BOF-Konvertes im Bereich von ca. 4000 Schmelzen, wohingegen die Haltbarkeit der ebenfalls mit einem feuerfesten Material ausgekleideten Seitenwände des Konverters etwa 7000 Schmelzen beträgt.The durability of the bottom with the purging blocks or blocks and the nozzles is based on the example of a 330t BOF converter in the range of about 4000 melts, whereas the durability of the likewise lined with a refractory material side walls of the converter is about 7000 melts.

Der Erfindung liegt daher die Aufgabe zugrunde, die vorstehend beschriebenen Nachteile zu vermeiden und ein Verfahren zu schaffen, mit dem die Haltbarkeit der Düsen und des Spülsteins bzw. -blocks erheblich verbessert und somit die Anzahl der Schmelzzyklen im Konverter gesteigert wird.The invention is therefore based on the object to avoid the disadvantages described above and to provide a method by which the durability of the nozzles and the purging plug or block significantly improved and thus the number of melting cycles in the converter is increased.

Diese Aufgabe wird erfindungsgemäß dadurch gelöst, dass über das Zentralrohr das Inertgas zumindest zeitweise zusammen mit Kohlenwasserstoff und gemeinsam mit einem durch den Ringspalt zwischen dem Zentralrohr und dem Außenrohr zugeführten, mit dem Inertgas bzw. Gasgemisch des Zentralrohres reagierenden Mantelgas, vorzugsweise Kohlenwasserstoff, eingeblasen wird, wobei das Mantelgas beim Zusammentreffen mit dem flüssigen Stahl gespalten wird und ein die Ringspaltdüsen kreisförmig umschließender, pilzförmiger, poröser Stahlmantel ausgebildet wird.This object is achieved in that the inert gas is at least temporarily injected together with hydrocarbon and together with a through the annular gap between the central tube and the outer tube, reacted with the inert gas or gas mixture of the central tube shell gas, preferably hydrocarbon, wherein the cladding gas cleaved upon contact with the liquid steel is formed and a circular gap surrounding the annular gap, mushroom-shaped, porous steel shell.

Das Inertgas, vorzugsweise Argon oder Stickstoff, und auch der Kohlenwasserstoff wird zur metallurgischen Behandlung der Metallschmelze als Kernstrahl erfindungsgemäß über das Zentralrohr bzw. die -düse in die Stahlschmelze eingeblasen, während das Mantelgas, neben Kohlenwasserstoff optional auch Wasserdampf oder CO2, als äußerer Ringstrahl eingeblasen wird. Die beim Zusammentreffen des Inertgases mit dem flüssigen Stahl dann einerseits hervorgerufene Badbewegung und andererseits bewirkte Spaltung des Mantelgases führt zu einer sehr viel Energie benötigenden Reaktion mit Erstarrung des flüssigen Stahls im Düsenbereich. In Abhängigkeit von der eingeblasenen Mantelgasmenge lassen sich der Durchmesser, z.B. bis 15 cm, und die Höhe, z.B. bis 4 cm, des pilzförmigen, porösen und die Düsen kreisförmig umschließenden Stahlmantels variieren. Der poröse Eisenpilz deckt somit zum einen den Spül- stein bzw. -block im Umgebungsbereich der Düsen ab, wodurch ein Verschleiß in Form von Auswaschungen des feuerfesten Materials verhindert wird. Zum anderen werden die Düsen durch die einhausende Abschottung vor Abbrand geschützt. Die nur zur Badbewegung dienende Düsenanordnung benötigt nur kleine Gasmengen, wobei sich eine Blasrate erreichen lässt, die etwa bei < 0,045 Nm3/t x Min. liegt.The inert gas, preferably argon or nitrogen, and also the hydrocarbon is injected for metallurgical treatment of the molten metal as a core jet according to the invention via the central tube or die in the molten steel, while the shell gas, in addition to hydrocarbon optionally also steam or CO 2 , as an outer ring beam blown. The on the one hand caused when the inert gas with the liquid steel then bath movement and on the other hand caused cleavage of the cladding gas leads to a very energy-consuming reaction with solidification of the liquid steel in the nozzle area. Depending on the injected jacket gas quantity, the diameter, for example up to 15 cm, and the height, for example up to 4 cm, of the mushroom-shaped, porous and circularly surrounding the nozzle steel shell can be varied. The porous iron fungus thus covers, on the one hand, the flushing stone or block in the surrounding area of the nozzles, which prevents wear in the form of leaching of the refractory material. On the other hand, the nozzles are protected by the einhausende foreclosure from burning. The only used for bath movement nozzle assembly requires only small amounts of gas, which can achieve a blow rate, which is about <0.045 Nm 3 / tx min.

Wenn sich der poröse Eisenpilz bzw. Stahlmantel bei der Verfestigung der Metallschmelze als Ansatz über der Spitze der zentralen Inertgas-Düse ausbilden und diese somit zusetzen sollte, kann vorteilhaft dem Inertgas temporär eine geringe Menge Sauerstoff zugemischt und dadurch die Inertgas-Düse bzw. das Zentralrohr freigebrannt werden.If the porous iron fungus or steel jacket forms as a batch over the top of the central inert gas nozzle during the solidification of the molten metal and thus should enforce it, advantageously a small amount of oxygen can be temporarily added to the inert gas and thereby the inert gas nozzle or the central tube be burned.

Gleiches gilt bei einem sich abzeichnenden Zusetzen des Ringspaltes für die das Mantelgas einblasende Düse, über den bzw. die dann kurzzeitig ebenfalls eine Inertgas-Sauerstoffmischung gefahren werden kann. Eine weitere Ausgestaltung der Erfindung sieht vor, dass jede Ringspaltdüse individuell geregelt und ein konstanter Druck aufrecht erhalten wird. Sollte es dabei trotz der vorher im Regelsystem festgelegten Druckparameter zu einer Druckerhöhung kommen, wobei sich sowohl das Zentralrohr als auch der Ringspalt zusetzen würden, erfolgt im Regelsystem so lange eine Umschaltung auf eine Sauerstoff- bzw. Inertgas-Beimischung, bis der vorher eingestellte, konstante Zieldruck wieder erreicht ist.The same applies to a looming clogging of the annular gap for the nozzle blowing the shell gas, over which or then briefly an inert gas-oxygen mixture can be driven. A further embodiment of the invention provides that each annular gap nozzle is controlled individually and a constant pressure is maintained. Should there be an increase in pressure in spite of the pressure parameters previously set in the control system, whereby both the central tube and the annular gap would become clogged, a changeover to an oxygen or inert gas admixture takes place in the control system until the previously set, constant Target pressure is reached again.

Ein weiterer Vorteil des Verfahrens ergibt sich, wenn der Konverter mit dem sogenannten „Slag Splashing" gefahren wird. Dabei handelt es sich um ein bekanntes Verfahren, bei dem man nach dem Konverterabstich die Restschlacke im Konverter behält. Auf diese Restschlacke werden dann mit Hilfe einer Toplanze große Mengen Stickstoff mit hohem Druck und hoher Geschwindigkeit in den Konverter geblasen. Die Restschlacke wird hierbei an die Seitenwände und an den Boden des Konvertergefäßes gespritzt.A further advantage of the method results when the converter is operated with the so-called "slag splashing." This is a known method in which the residual slag is retained in the converter after the converter has been cut off Top lance Large quantities of nitrogen are blown into the converter at high pressure and high speed, where the residual slag is sprayed to the side walls and to the bottom of the converter vessel.

Nach dem Einblasen lässt man die aufgespritzte Schlacke erstarren, so dass sich eine Schutzschicht für das feuerfeste Material im Boden und an den Seitenwänden bildet. Der erfindungsgemäß kreisförmig um die Ringspaltdüse ausgebildete, poröse, zudem sehr raue Eisenpilz vergrößert in diesem Bereich die Oberfläche. Da außerdem seine Oberfläche, relativ kalt ist, lässt sich auf diese Weise erreichen, dass ein Anbacken der verspritzten Schlacke auf dem Eisenpilz beschleunigt und die Haftung nach dem Erkalten verbessert wird.After injection, the sprayed slag is allowed to solidify, forming a protective layer for the refractory material in the bottom and sidewalls. The inventively designed in a circular manner around the annular gap, porous, also very rough iron fungus increases in this area the surface. In addition, since its surface is relatively cold, it is possible in this way to accelerate the caking of the sprayed slag on the iron fungus and to improve the adhesion after cooling.

Weitere Einzelheiten und Merkmale der Erfindung ergeben sich aus den An- Sprüchen und der nachfolgenden Beschreibung eines in den Zeichnungen anhand eines Bodenspülsteins schematisch dargestellten Ausführungsbeispiels der Erfindung. Es zeigen:Further details and features of the invention will become apparent from the claims and the following description of an embodiment of the invention schematically illustrated in the drawings with reference to a floor sink. Show it:

Fig. 1 in einer schematischen Schnittansicht einen konventionellen, im Stand der Technik bekannten Bodenspülstein eines BOF-Konverters, der zum1 is a schematic sectional view of a conventional, known in the art soil purging plug of a BOF converter, the

Spülen einer Stahlschmelze eine Düse aufweist; und Fig. 2 in einer schematischen Schnittansicht einen erfindungsgemäßen Bodenspülstein eines BOF-Konverters, der zum Spülen der Stahlschmelze eine Ringspaltdüsenanordnung aufweist.Rinsing a molten steel has a nozzle; and Fig. 2 is a schematic sectional view of a bottom spoiler of a BOF converter according to the invention, which has an annular gap nozzle arrangement for rinsing the molten steel.

Die Fig. 1 zeigt einen im Stand der Technik bekannten Bodenspülstein 1 eines hier nicht dargestellten BOF-Konverter zum Raffinieren, Mischen und/oder Spülen einer Stahlschmelze. Dazu weist der Bodenspülstein 1 ein Rohr 2 als Düse auf, über die ein Inertgas 3, beispielsweise Stickstoff, zur Badbewegung eingeblasen wird. Die Düse/das Rohr 2 ist in einem Monoblock 4 eingebettet, der aus einem feuerfesten Material, beispielsweise Keramik, besteht, der seinerseits von dem feuerfesten Material 5 der Auskleidung des Konverters umschlossen wird.Fig. 1 shows a known in the art soil rinse stone 1 of a BOF converter, not shown here for refining, mixing and / or rinsing a molten steel. For this purpose, the floor scavenger 1 a pipe 2 as a nozzle, via which an inert gas 3, for example nitrogen, is blown for bath movement. The nozzle / tube 2 is embedded in a monoblock 4, which consists of a refractory material, for example ceramic, which in turn is enclosed by the refractory material 5 of the lining of the converter.

Das Problem bei dieser Verfahrensweise ist, dass durch den hohen Druck und die große Geschwindigkeit des eingeblasenen Inertgases 3 das feuerfeste Material des Monoblocks 4 in der unmittelbaren Umgebung 6 der Düse 2 sowie auch diese selbst voreilend verschleißt .The problem with this procedure is that due to the high pressure and the high velocity of the injected inert gas 3, the refractory material of the monoblock 4 in the immediate vicinity 6 of the nozzle 2, as well as itself, wears prematurely.

Bei dem in Fig. 2 dargestellten Bodenspülstein 100 ist eine Düsenanordnung vorgesehen, die als Ringspaltdüse 11 aus dem Zentralrohr 2 und einem dieses konzentrisch mit einem Ringspalt 8 umschließenden Außenrohr 7 besteht. Der Düsendurchmesser des Zentralrohres 2 braucht nicht mehr als 5 mm und der der Ringspaltdüse 11 nicht mehr als 1 mm zu betragen.2, a nozzle arrangement is provided which consists of an annular pipe nozzle 11 made of the central pipe 2 and an outer pipe 7 enclosing this concentrically with an annular gap 8. The nozzle diameter of the central tube 2 does not need to be more than 5 mm and that of the annular gap nozzle 11 not more than 1 mm.

Über das Zentralrohr 2 wird Inertgas 3 und zeitweise Kohlenwasserstoff eingeblasen, während über den Ringspalt 8 der Ringspaltdüse 11 Kohlenwasserstoff und/oder Sauerstoff in einem Gemisch mit Inertgas als Mantelgas 9 geblasen wird. Beim Zusammentreffen des Mantelgases 9 mit der Stahlschmelze wird der Kohlenwasserstoff gespalten. Da diese Reaktion sehr viel Energie benötigt, wird ein Erstarren von Stahl in der unmittelbaren Umgebung 6 der Ringspaltdüse 11 erreicht. In Abhängigkeit von der eingeblasenen Menge des Mantelgases 9 bildet sich ein pilzförmiger, poröser Stahlmantel 10 kreisförmig um die Ringspaltdüsen 11.Inert gas 3 and intermittently hydrocarbon are injected via the central tube 2, while hydrocarbon and / or oxygen are blown through the annular gap 8 of the annular die 11 in a mixture with inert gas as the jacket gas 9. When the jacket gas 9 meets with the molten steel, the hydrocarbon is split. Since this reaction requires a lot of energy, a solidification of steel in the immediate vicinity 6 of the annular gap nozzle 11 is achieved. Depending on the injected quantity of the jacket gas 9, a mushroom-shaped, porous steel jacket 10 forms in a circle around the annular gap nozzles 11.

Der poröse Eisenpilz bzw. Stahlmantel 10 verhindert zum einen den voreilen- den Verschleiß des feuerfesten Materials des Monoblocks 4, da er schützend darüber liegt, und zum anderen einen Abbrand der Rohre 2, 7 der Ringspaltdüse 11 , da er diese konzentrisch umschließt und somit nach außen hin abschottet.The porous iron fungus or steel jacket 10 prevents, on the one hand, the premature wear of the refractory material of the monobloc 4, since it lies protectively over it, and, on the other hand, a burning of the tubes 2, 7 of the annular gap nozzle 11, since it surrounds them concentrically and thus after foreclosed on the outside.

Sollte der poröse Eisenpilz 10 das Zentralrohr 2 der Ringspaltdüse 11 zusetzen, kann dem Inertgas 3 eine geringe Menge Sauerstoff beigemischt werden. Durch die beigefügte Menge Sauerstoff und der damit einhergehenden Reaktion brennt das Zentralrohr 2 frei. Für den Ringspalt 8 kann ebenfalls eine Inertgas-Sauerstoffmischung gefahren werden, wenn sich ein Zusetzen abzeichnet. Der Sauerstoff dient somit nur zur Kontrolle bzw. Ausbildung der Grosse des Eisenpilzes 10.If the porous iron fungus 10 enforces the central tube 2 of the annular gap nozzle 11, a small amount of oxygen can be added to the inert gas 3. Due to the added amount of oxygen and the associated reaction, the central tube 2 burns freely. For the annular gap 8 can also be driven an inert gas-oxygen mixture, if clogging appears. The oxygen thus serves only to control or form the size of the iron fungus 10.

Somit ist vorgesehen, dass bei der Düsenanordnung über den Ringspalt 8 als Mantelgas 9 Cn Hx bzw. Ar oder N2 und (Ar + O2) + (N2 + O2) und über das Zentralrohr 2 ein Inertgas 3, z.B. Ar oder N2, und (Ar + O2) + (N2 + O2) gefahren werden kann.Thus, it is provided that in the nozzle assembly via the annular gap 8 as jacket gas 9 C n H x or Ar or N 2 and (Ar + O 2 ) + (N 2 + O 2 ) and the central tube 2, an inert gas 3, eg Ar or N 2 , and (Ar + O 2 ) + (N 2 + O 2 ) can be driven.

Die Ringspaltdüsen 11 des Konverters sind in einen Regelkreis eingebunden, der einerseits jedes Zentralrohr 2 und den Ringspalt 8 individuell ansteuert so- wie regelt und andererseits den Druck, mit dem die Düsen beaufschlagt werden, konstant hält. Sollte es dennoch zu einer über einem oberen Grenzwert liegenden Druckerhöhung kommen, wobei sich der Ringspalt 7 und/oder das Zentralrohr 2 zusetzt, wird über den Regelkreis das System so lange im Modus „Sauerstoff/Inertgas" gefahren, bis der Solldruck wieder erreicht ist. Bezugszeichenliste:The annular gap nozzles 11 of the converter are integrated into a control loop which on the one hand individually controls and regulates each central tube 2 and the annular gap 8 and on the other hand keeps constant the pressure with which the nozzles are acted upon. Should there nevertheless be an increase in pressure above an upper limit, the annular gap 7 and / or the central tube 2 becoming clogged, then the system is driven in the mode "oxygen / inert gas" via the control loop until the desired pressure is reached again. LIST OF REFERENCE NUMBERS

1 ; 100 Bodenspülstein1 ; 100 floor rinse stone

2 Rohr/Zentralrohr 3 Inertgas2 tube / central tube 3 inert gas

4 Monoblock4 monobloc

5 feuerfestes Material der Konverterauskleidung5 refractory material of the converter lining

6 Umgebungsbereich6 surrounding area

7 Außenrohr 8 Ringspalt/Spalt7 outer tube 8 annular gap / gap

9 Mantelgas9 jacket gas

10 poröser Stahlmantel / Eisenpilz10 porous steel casing / iron fungus

11 Ringspaltdüse 11 Annular gap nozzle

Claims

Patentansprüche: claims: 1. Verfahren zum Betreiben eines in verteilter Anordnung mehrere aus einem Zentralrohr (2) und einem Außenrohr (7) bestehende Ringspaltdü- sen (11) aufweisenden Bodenspülsystems (100) eines BOF-Konverters mit Inertgas-Einblasung zur Entkohlung der Schmelze im Konverter, dadurch gekennzeichnet, dass über das Zentralrohr (2) das Inertgas zumindest zeitweise zusammen mit Kohlenwasserstoff und gemeinsam mit einem durch den Spalt (8) zwischen dem Zentralrohr (2) und dem Außenrohr (7) zugeführten, mit dem Inertgas bzw. Gasgemisch des Zentralrohres (2) reagierenden Mantelgas (9) eingeblasen wird, wobei das Mantelgas beim Zusammentreffen mit dem flüssigen Stahl gespalten wird und ein die Ringspaltdüsen (11) kreisförmig umschließender, pilzförmiger, poröser Stahlmantel (10) ausgebildet wird.1. A method for operating in a distributed arrangement of a plurality of a central tube (2) and an outer tube (7) existing annular gap nozzles (11) having floor washes (100) of a BOF converter with inert gas injection for decarburization of the melt in the converter, characterized characterized in that via the central tube (2), the inert gas at least temporarily together with hydrocarbon and together with a through the gap (8) between the central tube (2) and the outer tube (7) supplied, with the inert gas or gas mixture of the central tube (2 ) is blown, wherein the cladding gas is cleaved upon contact with the liquid steel and the annular gap nozzles (11) circular enclosing, mushroom-shaped, porous steel shell (10) is formed. 2. Verfahren nach Anspruch 1 , dadurch gekennzeichnet, dass als Mantelgas Kohlenwasserstoff, Wasserdampf oder CO2 einge- blasen wird.2. The method according to claim 1, characterized in that as a shell gas hydrocarbon, water vapor or CO 2 is blown. 3. Verfahren nach Anspruch 1 oder 2, dadurch gekennzeichnet, dass dem Inertgas und/oder dem Mantelgas beim Einblasen temporär eine Sauerstoffmenge zugemischt wird.3. The method according to claim 1 or 2, characterized in that the inert gas and / or the cladding gas during injection temporarily an amount of oxygen is added. 4. Verfahren nach einem der Ansprüche 1 bis 3, dadurch gekennzeichnet, dass jede Ringspaltdüse individuell geregelt und ein konstanter Druck aufrecht erhalten wird. 4. The method according to any one of claims 1 to 3, characterized in that each annular gap nozzle is controlled individually and a constant pressure is maintained.
PCT/EP2010/003411 2009-06-09 2010-06-08 Method for operating a bottom purging system of a bof converter Ceased WO2010142407A1 (en)

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DE102010020179A DE102010020179A1 (en) 2009-06-09 2010-05-11 Method for operating a floor flushing system of a BOF converter

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CN103591804B (en) * 2013-11-28 2015-01-14 甘肃维新工程设备有限公司 Method for repairing lining brick of steel structure lining brick equipment
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JPS5819424A (en) * 1981-07-28 1983-02-04 Kawasaki Steel Corp Controlling method for cooling of bottom tuyere of converter
US4435211A (en) * 1980-12-05 1984-03-06 Metallgesellschaft Aktiengesellschaft Process of blowing high-oxygen gases into a molten bath which contains non-ferrous metals
EP0644269A1 (en) * 1993-09-21 1995-03-22 The Gas Research Institute Process for controlling the forming of an accretion on an oxy-fuel tuyere
WO1999029913A1 (en) * 1997-12-11 1999-06-17 Quantum Catalytics, L.L.C. Feed injection device and method for control of accretion
EP1641946B1 (en) 2003-06-25 2007-02-21 Voest-Alpine Industrieanlagenbau GmbH & Co. Method for producing an alloy molten metal

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Publication number Priority date Publication date Assignee Title
US4435211A (en) * 1980-12-05 1984-03-06 Metallgesellschaft Aktiengesellschaft Process of blowing high-oxygen gases into a molten bath which contains non-ferrous metals
JPS5819424A (en) * 1981-07-28 1983-02-04 Kawasaki Steel Corp Controlling method for cooling of bottom tuyere of converter
EP0644269A1 (en) * 1993-09-21 1995-03-22 The Gas Research Institute Process for controlling the forming of an accretion on an oxy-fuel tuyere
WO1999029913A1 (en) * 1997-12-11 1999-06-17 Quantum Catalytics, L.L.C. Feed injection device and method for control of accretion
EP1641946B1 (en) 2003-06-25 2007-02-21 Voest-Alpine Industrieanlagenbau GmbH & Co. Method for producing an alloy molten metal

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