EP0832301B1 - Process for post-combustion of reaction gases produced during the vacuum processing of steel and apparatus for carring out the process. - Google Patents

Process for post-combustion of reaction gases produced during the vacuum processing of steel and apparatus for carring out the process. Download PDF

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Publication number
EP0832301B1
EP0832301B1 EP96919573A EP96919573A EP0832301B1 EP 0832301 B1 EP0832301 B1 EP 0832301B1 EP 96919573 A EP96919573 A EP 96919573A EP 96919573 A EP96919573 A EP 96919573A EP 0832301 B1 EP0832301 B1 EP 0832301B1
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Prior art keywords
air
reaction vessel
reaction
steel
process according
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EP96919573A
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German (de)
French (fr)
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EP0832301A1 (en
Inventor
Karl Brotzmann
Heinz Holtermann
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Technometal Gesellschaft fuer Metalltechnologie mbH
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Technometal Gesellschaft fuer Metalltechnologie mbH
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    • 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
    • C21C7/00Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
    • C21C7/10Handling in a vacuum
    • 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
    • F27D17/00Arrangements for using waste heat; Arrangements for using, or disposing of, waste gases
    • F27D17/001Extraction of waste gases, collection of fumes and hoods used therefor
    • 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
    • F27D17/00Arrangements for using waste heat; Arrangements for using, or disposing of, waste gases
    • F27D17/004Systems for reclaiming waste heat
    • 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
    • C21C2100/00Exhaust gas
    • C21C2100/02Treatment of the exhaust 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
    • F27D19/00Arrangements of controlling devices
    • F27D2019/0006Monitoring the characteristics (composition, quantities, temperature, pressure) of at least one of the gases of the kiln atmosphere and using it as a controlling value
    • F27D2019/0012Monitoring the composition of the atmosphere or of one of their components
    • F27D2019/0015Monitoring the composition of the exhaust gases or of one of its components

Definitions

  • the invention relates to a method for the afterburning of when decarburizing liquid steel in under vacuum reaction gases arising from standing reaction vessels, being opposite to the direction of flow of the reaction gases Air flow is introduced into the reaction vessel.
  • DE 41 30 590 C2 describes a degassing vessel as Reaction vessel for the vacuum treatment of liquid steel described; as can be seen from this document, become particles by the degassing stream of the reaction gases carried away, which leads to the fact that in the upper part of the Reaction vessel and in the area of the connecting line for the Vacuum pump to a strong buildup of Steel splashes comes, such collections also as "Steel bears" are called. These steel bears can be a have considerable weight and finally the upper one Close part of the reaction vessel largely, so that in the general the steel bear in an elaborate manner Burning out must be eliminated.
  • FR 1 575 991 used to form the genus describes a method in which a Reaction vessel against the flow direction of the Reaction gases an air stream by means of the bath surface directed lances with a short distance to them is blown in. Blowing in air is one Afterburn is associated, however, due to the Ambient temperature of the blown air generated energy for the prevention of steel deposits in the Reaction vessel not sufficient.
  • the invention is therefore based on the object To improve methods of the type mentioned at the outset in such a way that the danger of the formation of steel approaches - bears - in Reaction vessel is further reduced; Furthermore, one should Implementation of an improved process Device can be specified.
  • the basic idea of the invention provides that the one arranged in the refractory delivery Air flow from hot air with a There is a temperature between 800 ° C and 1400 ° C.
  • the invention has the advantage that hot air due to their own high blowing speed has much higher energy impulse and thus over the Length / height of the reaction vessel against the Direction of flow of the reaction gases penetrates very deep. This creates a sufficiently strong swirling of the Reaction gases associated with the hot air jet, resulting in a better combustion of the reaction gases and a better one Heat transfer to the inside of the wall of the Reaction vessel leads.
  • the reason for this is that Air under the usual conditions only with maximum The speed of sound is blown into the reaction vessel can be; the speed of sound is for cold air only at 330 m / s, whereas the speed of sound for Air with a temperature of For example, 1200 ° C is about 800 m / s. Through the So using hot air it is possible to use the air much higher speed into the reaction vessel bring in.
  • the amount of air introduced is such that the air from the degassing steel batch calculated amount of reaction gases is completely burned stoichiometrically; it understands yourself that in order to achieve this goal the blow-in Air volume of the amount of reaction gases generated is to be adjusted.
  • first period for example, within the first three minutes vacuum decarburization lasting about 12 minutes, about 50% of the Reaction gases are sucked out and during the subsequent another three minutes, another 25% can be suctioned off, it can expedient according to an embodiment of the invention be that introducing air at first Period of vacuum treatment of the liquid steel is concentrated, this first period with the Half of the total duration of treatment can be measured.
  • the introduction of air into the Reaction tube only for every 2nd or 3rd batch is made because it may be desirable that the Protect the refractory lining of the reaction vessel thin steel shirt left on the vessel lining should.
  • a convenient device for performing the method is aimed at a suitable generator for To provide generation of hot air, and according to the invention the generator is a bed of heat heatable balls made of a refractory material Heating of the air led through the ball bed.
  • the ball bed can be heated up after a Embodiment of the invention, a separate burner be provided, or it can be the generator Waste heat can be connected to the reaction vessel, so that the hot air there after the treatment for Heating the ball bed can be used.
  • the reaction vessel 10 instructs at its lower end two dip tubes 11 with which the Reaction vessel connected to a steel pan in which there is liquid steel; is in the Reaction vessel via connection 16 for a vacuum pump Vacuum applied, so rises from the not shown Steel pan on the steel bath 12 in the direction of arrow 13 and enters the reaction vessel 10 and continues to flow appropriate treatment or degassing in Direction of arrow 14 back into the steel pan; at this treatment emerge from the steel bath 12 Reaction gases 15, which are directed towards the connection opening 16 flow for the vacuum pump.
  • Injection opening 17 In the upper cover of the reaction vessel 10 there is one Injection opening 17, through which in the described Embodiment hot air in the reaction vessel 10 blown in or via that in the reaction vessel 10 current vacuum is sucked into the reaction vessel 10, a flame 19 extending from the injection opening 17 forms, which is surrounded by a hot air column 18 or continues in this.
  • the in the Figure 1 relationships are based on a Blown hot air speed of 600 m / s at a flow rate of the reaction gases of 15 m / s, with a total height of the reaction vessel from 10 - 12 m the hot air deep into the reaction vessel 10 penetrates and thus a heat transfer into the lower Ensures the area of the reaction vessel.
  • the corresponding vacuum treatment is shown in FIG or the hot air blowing shown each the amount of reaction gas or hot air is plotted over the duration of treatment; this
  • the illustration shows the vacuum treatment of a 280 t steel batch basis, and this results in curve 20 of extracted amount of reaction gas over the treatment period of about 12 minutes; the hot air is at a temperature of 1200 ° C in an amount corresponding to curve 21 blown in the time axis, being shown in the Embodiment blowing the hot air on the Half of the treatment time, i.e. limited to 6 minutes is.
  • the measured exhaust gas temperature was 1800 ° C, and from this one is calculated for melting one Steel bears available energy of 0.88 GJ, which is sufficient is a steel bear weighing approximately 1.5 tons to melt.
  • FIG 3 is an appropriate generator arrangement for Generation of hot air is shown, the associated Generator 22 via a connecting line 23 to the Injection opening 17 for the hot air in the reaction vessel 10 connected; the connecting line 23 is via a Valve 24 can be shut off.
  • the generator 22 has a bed 25 of one fireproof material existing balls, being used for Heating of the ball bed 25 a separate, for example, gas-operated burner 26 is provided is, which in turn is connected to the connecting line 23 is.
  • An air line 27 also leads into the generator into a lockable by means of a valve 29 Exhaust line 28 and into one by means of a valve 31 lockable inlet line 30 branches.
  • the valve is 24 closed, as well as the valve 31 in the inlet line 30; this means that the gas burner 26 is called Exhaust gases flow through the ball bed 25 and over the Exhaust pipe 28 exit with valve 29 open; for the Blowing in hot air, the valve 29 is closed, and valves 31 and 24 are opened; due to the im Reaction vessel 10 prevailing vacuum, the air can now enter generator 22 via lines 30 and 27 and is here on the heated ball bed 25 Brought temperature; the heated hot air then comes out via the connecting line 23 with the valve 24 open in the Reaction vessel 10 via the injection opening 17; is there it is appropriate that the connecting line 23 between the generator 22 and reaction vessel 10 is dimensioned as short as possible.
  • the injection opening 17 in the reaction vessel is also like this dimensioned that at the internal pressure to be applied in each case or vacuum in the reaction vessel in each case best possible flow conditions for the entry of the Hot air exist.
  • the valve 24 is in both Embodiments depending on the in Reaction vessel 10 prevailing vacuum regulation of amount of hot air to be admitted into the reaction vessel 10 given.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Environmental & Geological Engineering (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Treatment Of Steel In Its Molten State (AREA)
  • Waste-Gas Treatment And Other Accessory Devices For Furnaces (AREA)
  • Furnace Details (AREA)

Description

Die Erfindung betrifft ein Verfahren zur Nachverbrennung von bei der Entkohlung von flüssigem Stahl in unter Vakuum stehenden Reaktionsgefäßen entstehenden Reaktionsgasen, wobei entgegen der Strömungsrichtung der Reaktionsgase ein Luftstrom in das Reaktionsgefäß eingebracht wird.The invention relates to a method for the afterburning of when decarburizing liquid steel in under vacuum reaction gases arising from standing reaction vessels, being opposite to the direction of flow of the reaction gases Air flow is introduced into the reaction vessel.

In der DE 41 30 590 C2 ist ein Entgasungsgefäß als Reaktionsgefäß für die Vakuumbehandlung von flüssigem Stahl beschrieben; wie dieser Druckschrift zu entnehmen ist, werden durch den Entgasungsstrom der Reaktionsgase Partikel mitgerissen, was dazu führt, daß es im oberen Teil des Reaktionsgefäßes und im Bereich der Anschlußleitung für die Vakuumpumpe zu einer starken Ansatzbildung von Stahlspritzern kommt, wobei derartige Ansammlungen auch als "Stahlbären" bezeichnet werden. Diese Stahlbären können ein erhebliches Gewicht aufweisen und schließlich den oberen Teil des Reaktionsgefäßes weitgehend verschließen, so daß im allgemeinen der Stahlbär in aufwendiger Weise durch Herausbrennen beseitigt werden muß.DE 41 30 590 C2 describes a degassing vessel as Reaction vessel for the vacuum treatment of liquid steel described; as can be seen from this document, become particles by the degassing stream of the reaction gases carried away, which leads to the fact that in the upper part of the Reaction vessel and in the area of the connecting line for the Vacuum pump to a strong buildup of Steel splashes comes, such collections also as "Steel bears" are called. These steel bears can be a have considerable weight and finally the upper one Close part of the reaction vessel largely, so that in the general the steel bear in an elaborate manner Burning out must be eliminated.

Zur Vermeidung einer derartigen Bärenbildung ist in der insoweit zur Bildung der Gattung herangezogenen EP 0 347 884 B1 ein Verfahren vorgeschlagen, mittels dessen eine Nachverbrennung der entstehenden Reaktionsgase angestrebt wird. Im Rahmen dieses bekannten Verfahrens wird über eine in das Reaktionsgefäß bis auf einen definierten Abstand zur Oberfläche des Stahlbades des flüssigen Stahls einfahrbare Lanze Sauerstoff beziehungsweise ein sauerstoffhaltiges Gas in einer im einzelnen zu berechnenden Menge auf das Stahlbad geblasen; mit diesem bekannten Verfahren sollen drei Effekte gemeinsam erreicht werden, nämlich eine Entkohlung des Stahls über die Sauerstoffzufuhr, eine Aufheizung des Stahlbades sowie eine Nachverbrennung der bei der Vakuumbehandlung entstehenden Reaktiongsgase. Dabei hat es sich in der Praxis gezeigt, daß mit dem bekannten Verfahren das Entstehen von Stahlbären insbesondere in langgestreckten beziehungsweise hohen Reaktionsgefäßen nicht ausreichend sicher verhindert werden kann.To avoid such bear formation is in the insofar as used to form the genus EP 0 347 884 B1 proposed a method by means of which afterburning of the resulting reaction gases is sought. In the context of this known method via a into the reaction vessel except for a defined one Distance to the surface of the molten steel bath retractable lance oxygen or oxygen-containing gas in one to be calculated in detail Amount blown onto the steel bath; with this known Three effects are to be achieved together, namely decarburization of the steel via the Oxygen supply, heating the steel bath and a Afterburning of the resulting from the vacuum treatment Reaction gases. It has been shown in practice that with the known method the emergence of steel bears especially in elongated or high Reaction vessels cannot be prevented with sufficient certainty can.

In der zur Bildung der Gattung herangezogenen FR 1 575 991 ist ein Verfahren beschrieben, bei welchem in ein Reaktionsgefäß entgegen der Strömungsrichtung der Reaktionsgase ein Luftstrom mittels auf die Badoberfläche gerichteter und mit geringem Abstand dazu endender Lanzen eingeblasen wird. Zwar geht mit dem Einblasen von Luft eine Nachverbrennung einher, jedoch ist aufgrund der Umgebungstemperatur der eingeblasenen Luft die damit erzeugte Energie für die Verhinderung von Stahlansätzen im Reaktionsgefäß nicht ausreichend.In FR 1 575 991 used to form the genus describes a method in which a Reaction vessel against the flow direction of the Reaction gases an air stream by means of the bath surface directed lances with a short distance to them is blown in. Blowing in air is one Afterburn is associated, however, due to the Ambient temperature of the blown air generated energy for the prevention of steel deposits in the Reaction vessel not sufficient.

Der Erfindung liegt daher die Aufgabe zugrunde, ein Verfahren der eingangs genannten Art derart zu verbessern, daß die Gefahr der Bildung von Stahlansätzen - Bären - im Reaktionsgefäß weiter verringert ist; ferner soll eine zur Durchführung eines verbesserten Verfahrens geeignete Vorrichtung angegeben werden.The invention is therefore based on the object To improve methods of the type mentioned at the outset in such a way that the danger of the formation of steel approaches - bears - in Reaction vessel is further reduced; Furthermore, one should Implementation of an improved process Device can be specified.

Die Lösung dieser Aufgabe ergibt sich einschließlich vorteilhafter Ausgestaltungen und Weiterbildungen aus dem Inhalt der Patentansprüche, welche dieser Beschreibung nachgestellt sind. The solution to this problem is inclusive advantageous refinements and developments from Content of the claims which this description are reproduced.

Die Erfindung sieht in ihrem Grundgedanken vor, daß der über eine in der Feuerfestzustellung angeordnete Einblasöffnung eingebrachte Luftstrom aus Heißluft mit einer Temperatur zwischen 800° C bis 1400° C besteht.The basic idea of the invention provides that the one arranged in the refractory delivery Air flow from hot air with a There is a temperature between 800 ° C and 1400 ° C.

Mit der Erfindung ist der Vorteil verbunden, daß Heißluft aufgrund der ihr eigenen hohen Einblasgeschwindigkeit einen wesentlich höheren Energieimpuls aufweist und damit über die Länge/Höhe des Reaktionsgefäßes entgegen der Strömungsrichtung der Reaktionsgase sehr tief eindringt. Damit geht eine ausreichend starke Verwirbelung der Reaktionsgase mit dem Heißluftstrahl einher, was zu einer besseren Verbrennung der Reaktionsgase und zu einer besseren Wärmeübertragung an die Innenseite der Wand des Reaktionsgefäßes führt. Der Grund hierfür liegt darin, daß Luft unter den üblichen Bedingungen nur maximal mit Schallgeschwindigkeit in das Reaktionsgefäß eingeblasen werden kann; für kalte Luft liegt die Schallgeschwindigkeit nur bei 330 m/s, wohingegen die Schallgeschwindigkeit für Luft mit einer Temperatur von beispielsweise 1200° C bei ca. 800 m/s liegt. Durch die Verwendung heißer Luft ist es also möglich, die Luft mit wesentlich höherer Geschwindigkeit in das Reaktionsgefäß einzubringen.The invention has the advantage that hot air due to their own high blowing speed has much higher energy impulse and thus over the Length / height of the reaction vessel against the Direction of flow of the reaction gases penetrates very deep. This creates a sufficiently strong swirling of the Reaction gases associated with the hot air jet, resulting in a better combustion of the reaction gases and a better one Heat transfer to the inside of the wall of the Reaction vessel leads. The reason for this is that Air under the usual conditions only with maximum The speed of sound is blown into the reaction vessel can be; the speed of sound is for cold air only at 330 m / s, whereas the speed of sound for Air with a temperature of For example, 1200 ° C is about 800 m / s. Through the So using hot air it is possible to use the air much higher speed into the reaction vessel bring in.

Vereinfacht entsteht durch das Einbringen von Luft in das Reaktionsgefäß bei Zutritt der Reaktionsgase eine langgestreckte große Flamme, die über die Einblasmenge sowie die Einblasgeschwindigkeit regelbar ist; mittels dieser großen Flamme lassen sich auch gegebenenfalls bereits bestehende Stahlbären größeren Ausmaßes verhältnismäßig schnell wieder abschmelzen. Vorteilhaft ist aber, daß die Abgase der durch das Einblasen von Luft herbeigeführten Nachverbrennung der Reaktionsgase verhältnismäßig kalt sind, so daß auch die Abgasbehandlung der aus dem Reaktionsgefäß abgesaugten Gase vereinfacht ist.Simplified is created by introducing air into the Reaction vessel when the reaction gases enter elongated large flame that over the amount of injection as well the blowing speed is adjustable; by means of this large flame can already be used if necessary existing steel bears proportionately large melt away quickly. But it is advantageous that the Exhaust gases caused by blowing air Afterburning of the reaction gases are relatively cold, so that the exhaust gas treatment from the reaction vessel extracted gases is simplified.

Nach einem Ausführungsbeispiel der Erfindung ist die eingebrachte Luftmenge so bemessen, daß die aus der zu entgasenden Stahlcharge berechnete Menge an Reaktionsgasen stöchiometrisch vollständig verbrannt wird; es versteht sich, daß zur Erreichung dieses Zieles die einzublasende Luftmenge der Menge der entstehenden Reaktionsgase anzupassen ist.According to an embodiment of the invention The amount of air introduced is such that the air from the degassing steel batch calculated amount of reaction gases is completely burned stoichiometrically; it understands yourself that in order to achieve this goal the blow-in Air volume of the amount of reaction gases generated is to be adjusted.

Hierbei ist nach einem Ausführungsbeispiel der Erfindung vorgesehen, daß das Einbringen von Luft über die gesamte Zeitdauer der Vakuumentgasung des flüssigen Stahls erfolgt; diese Maßnahme dient dazu, während der gesamten Vakuumbehandlung des Stahls möglichst ein CO-freies Abgas zu erzielen. This is according to an embodiment of the invention provided that the introduction of air over the total time of vacuum degassing of the liquid Steel is done; this measure is used during the Whole vacuum treatment of the steel, if possible, a CO-free To achieve exhaust gas.

Da bekanntlich innerhalb eines ersten Zeitabschnitts, beispielsweise innerhalb der ersten drei Minuten einer etwa zwölf Minuten dauernden Vakuumentkohlung etwa 50 % der Reaktionsgase abgesaugt und während der nachfolgenden weiteren drei Minuten weitere 25 % abgesaugt werden, kann es nach einem Ausführungsbeispiel der Erfindung zweckmäßig sein, daß das Einbringen von Luft auf den ersten Zeitabschnitt der Vakuumbehandlung des flüssigen Stahls konzentriert ist, wobei dieser erste Zeitabschnitt mit der Hälfte der gesamten Behandiungsdauer bemessen sein kann.As we know within a first period, for example, within the first three minutes vacuum decarburization lasting about 12 minutes, about 50% of the Reaction gases are sucked out and during the subsequent another three minutes, another 25% can be suctioned off, it can expedient according to an embodiment of the invention be that introducing air at first Period of vacuum treatment of the liquid steel is concentrated, this first period with the Half of the total duration of treatment can be measured.

Nach alternativen Ausführungsbeispielen der Erfindung kann vorgesehen sein, daß das Einbringen von Luft in das Reaktionsgefäß nur bei jeder 2. beziehungsweise 3. Charge vorgenommen wird, weil es erwünscht sein kann, daß zum Schutze der feuerfesten Auskleidung des Reaktionsgefäßes ein dünnes Stahlhemd auf der Gefäßauskleidung belassen werden soll.According to alternative embodiments of the invention be provided that the introduction of air into the Reaction tube only for every 2nd or 3rd batch is made because it may be desirable that the Protect the refractory lining of the reaction vessel thin steel shirt left on the vessel lining should.

In an sich bekannter Weise ist das erfindungsgemäße Verfahren zur Nachverbrennung der Reaktionsgase auch zu kombinieren mit einer beschleunigten Entkohlungsbehandlung des flüssigen Stahls, bei welcher über eine einfahrbare Lanze Sauerstoff in das Stahlbad eingebracht wird.In a manner known per se, this is the invention Processes for post-combustion of the reaction gases too combine with accelerated decarburization treatment of the liquid steel, in which a retractable Lance of oxygen is introduced into the steel bath.

Eine zweckmäßige Vorrichtung zur Durchführung des Verfahrens ist darauf gerichtet, einen geeigneten Generator zur Erzeugung der Heißluft vorzusehen, und erfindungsgemäß weist der Generator eine Schüttung von durch Wärmezufuhr aufheizbaren Kugeln aus einem feuerfesten Material zur Aufheizung der durch die Kugelschüttung geführten Luft auf. Zur Aufheizung der Kugelschüttung kann nach einem Ausführungsbeispiel der Erfindung ein gesonderter Brenner vorgesehen sein, oder es kann der Generator zur Abwärmenutzung an das Reaktionsgefäß angeschlossen sein, so daß die dort nach der Behandlung anstehende heiße Luft zur Aufheizung der Kugelschüttung herangezogen werden kann.A convenient device for performing the method is aimed at a suitable generator for To provide generation of hot air, and according to the invention the generator is a bed of heat heatable balls made of a refractory material Heating of the air led through the ball bed. The ball bed can be heated up after a Embodiment of the invention, a separate burner be provided, or it can be the generator Waste heat can be connected to the reaction vessel, so that the hot air there after the treatment for Heating the ball bed can be used.

In der Zeichnung sind Ausführungsbeispiel der Erfindung wiedergegeben, welche nachstehend beschrieben sind; es zeigen:

Fig. 1
ein Reaktionsgefäß während des Einblasens von Heißluft in einer schematischer Darstellung,
Fig. 2
in einem Diagramm das Verhältnis von entstehenden Reaktionsgasen und eingeblasener Luftmenge zur Behandlungsdauer,
Fig. 3
einen Generator zur Heißlufterzeugung in Verbindung mit dem Reaktionsgefäß in einer schematischen Darstellung,
Fig. 4
den Gegenstand der Figur 3 in einem anderen Ausführungsbeispiel.
In the drawing, embodiment of the invention are shown, which are described below; show it:
Fig. 1
a reaction vessel during the blowing in of hot air in a schematic representation,
Fig. 2
the relationship between the resulting reaction gases and the amount of air blown in to the treatment duration in a diagram,
Fig. 3
a generator for hot air generation in connection with the reaction vessel in a schematic representation,
Fig. 4
the subject of Figure 3 in another embodiment.

Wie aus Figur 1 ersichtlich, weist das Reaktionsgefäß 10 an seinem unteren Ende zwei Tauchrohre 11 auf, mit denen das Reaktionsgefäß in Verbindung mit einer Stahlpfanne gebracht wird, in der sich flüssiger Stahl befindet; wird in dem Reaktionsgefäß über den Anschluß 16 für eine Vakuumpumpe Unterdruck angelegt, so steigt aus der nicht dargestellten Stahlpfanne das Stahlbad 12 in Richtung des Pfeiles 13 auf und tritt in das Reaktionsgefäß 10 ein und fließt nach entsprechender Behandlung beziehungsweise Entgasung in Richtung des Pfeiles 14 in die Stahlpfanne zurück; bei dieser Behandlung entstehen aus dem Stahlbad 12 austretende Reaktionsgase 15, die in Richtung auf die Anschlußöffnung 16 für die Vakuumpumpe strömen.As can be seen from FIG. 1, the reaction vessel 10 instructs at its lower end two dip tubes 11 with which the Reaction vessel connected to a steel pan in which there is liquid steel; is in the Reaction vessel via connection 16 for a vacuum pump Vacuum applied, so rises from the not shown Steel pan on the steel bath 12 in the direction of arrow 13 and enters the reaction vessel 10 and continues to flow appropriate treatment or degassing in Direction of arrow 14 back into the steel pan; at this treatment emerge from the steel bath 12 Reaction gases 15, which are directed towards the connection opening 16 flow for the vacuum pump.

Im oberen Deckel des Reaktionsgefäßes 10 befindet sich eine Einblasöffnung 17, über die bei dem beschriebenen Ausführungsbeispiel Heißluft in das Reaktionsgefäß 10 eingeblasen beziehungsweise über das im Reaktionsgefäß 10 anstehende Vakuum in das Reaktionsgefäß 10 eingesaugt wird, wobei sich von der Einblasöffnung 17 aus eine Flamme 19 ausbildet, die von einer Heißluftsäule 18 umgeben ist beziehungsweise sich in diese fortsetzt. Die in der Figur 1 dargestellten Verhältnisse beruhen auf einer Geschwindigkeit der eingeblasenen Heißluft in Höhe von 600 m/s bei einer Strömungsgeschwindigkeit der Reaktionsgase von 15 m/s, wobei bei einer Gesamthöhe des Reaktionsgefäßes von 10 - 12 m die Heißluft tief in das Reaktionsgefäß 10 eindringt und damit eine Wärmeübertragung bis in den unteren Bereich des Reaktionsgefäßes sicherstellt.In the upper cover of the reaction vessel 10 there is one Injection opening 17, through which in the described Embodiment hot air in the reaction vessel 10 blown in or via that in the reaction vessel 10 current vacuum is sucked into the reaction vessel 10, a flame 19 extending from the injection opening 17 forms, which is surrounded by a hot air column 18 or continues in this. The in the Figure 1 relationships are based on a Blown hot air speed of 600 m / s at a flow rate of the reaction gases of 15 m / s, with a total height of the reaction vessel from 10 - 12 m the hot air deep into the reaction vessel 10 penetrates and thus a heat transfer into the lower Ensures the area of the reaction vessel.

In Figur 2 ist die entsprechende Vakuumbehandlung beziehungsweise das Heißlufteinblasen dargestellt, wobei jeweils die Menge an Reaktionsgas beziehungsweise Heißluft über der Behandlungsdauer aufgetragen ist; dieser Darstellung liegt die Vakuumbehandlung einer 280 t-Stahlcharge zugrunde, und dabei ergibt sich die Kurve 20 der abgesaugten Menge an Reaktionsgas über der Behandlungsdauer von etwa 12 Minuten; die Heißluft wird mit einer Temperatur von 1200° C in einer der Kurve 21 entsprechenden Menge über der Zeitachse eingeblasen, wobei in dem dargestellten Ausführungsbeispiel das Einblasen der Heißluft auf die Hälfte der Behandlungsdauer, also auf 6 Minuten, beschränkt ist. Die gemessene Abgastemperatur betrug dabei 1800° C, und hieraus errechnet sich eine für das Abschmelzen eines Stahlbären verfügbare Energie von 0,88 GJ, was ausreichend ist, um einen Stahlbären von ungefähr 1,5 t Gewicht abzuschmelzen.The corresponding vacuum treatment is shown in FIG or the hot air blowing shown each the amount of reaction gas or hot air is plotted over the duration of treatment; this The illustration shows the vacuum treatment of a 280 t steel batch basis, and this results in curve 20 of extracted amount of reaction gas over the treatment period of about 12 minutes; the hot air is at a temperature of 1200 ° C in an amount corresponding to curve 21 blown in the time axis, being shown in the Embodiment blowing the hot air on the Half of the treatment time, i.e. limited to 6 minutes is. The measured exhaust gas temperature was 1800 ° C, and from this one is calculated for melting one Steel bears available energy of 0.88 GJ, which is sufficient is a steel bear weighing approximately 1.5 tons to melt.

In Figur 3 ist eine zweckmäßige Generatoranordnung für die Erzeugung der Heißluft dargestellt, wobei der zugehörige Generator 22 über eine Anschlußleitung 23 an die Einblasöffnung 17 für die Heißluft im Reaktionsgefäß 10 angeschlossen ist; die Anschlußleitung 23 ist über ein Ventil 24 absperrbar.In Figure 3 is an appropriate generator arrangement for Generation of hot air is shown, the associated Generator 22 via a connecting line 23 to the Injection opening 17 for the hot air in the reaction vessel 10 connected; the connecting line 23 is via a Valve 24 can be shut off.

Der Generator 22 weist eine Schüttung 25 von aus einem feuerfesten Material bestehenden Kugeln auf, wobei zur Aufheizung der Kugelschüttung 25 ein gesonderter, beispielsweise mit Gas betriebener Brenner 26 vorgesehen ist, der seinerseits an die Anschlußleitung 23 angeschlossen ist. In den Generator führt ferner eine Luftleitung 27, die sich in eine mittels eines Ventils 29 absperrbare Abgasleitung 28 und in eine mittels eines Ventils 31 absperrbare Einlaßleitung 30 verzweigt.The generator 22 has a bed 25 of one fireproof material existing balls, being used for Heating of the ball bed 25 a separate, for example, gas-operated burner 26 is provided is, which in turn is connected to the connecting line 23 is. An air line 27 also leads into the generator into a lockable by means of a valve 29 Exhaust line 28 and into one by means of a valve 31 lockable inlet line 30 branches.

Während des Aufheizens der Kugelschüttung 25 ist das Ventil 24 geschlossen, ebenso das Ventil 31 in der Einlaßleitung 30; damit können die vom Gasbrenner 26 eingebrachten heißen Abgase die Kugelschüttung 25 durchströmen und über die Abgasleitung 28 bei geöffnetem Ventil 29 austreten; für das Einblasen von Heißluft wird das Ventil 29 geschlossen, und es werden die Ventile 31 und 24 geöffnet; aufgrund des im Reaktionsgefäß 10 herrschenden Vakuums kann die Luft nun über die Leitungen 30 und 27 in den Generator 22 eintreten und wird hier über die aufgeheizte Kugelschüttung 25 auf Temperatur gebracht; die aufgeheizte Heißluft tritt alsdann über die Anschlußleitung 23 bei geöffnetem Ventil 24 in das Reaktionsgefäß 10 über die Einblasöffnung 17 ein; dabei ist es zweckmäßig, daß die Anschlußleitung 23 zwischen Generator 22 und Reaktionsgefäß 10 möglichst kurz bemessen ist. Weiterhin ist die Einblasöffnung 17 im Reaktionsgefäß so dimensioniert, daß bei dem jeweils anzulegenden Innendruck beziehungsweise Vakuum im Reaktionsgefäß jeweils bestmögliche Strömungsbedingungen für das Eintreten der Heißluft bestehen.During the heating of the ball bed 25, the valve is 24 closed, as well as the valve 31 in the inlet line 30; this means that the gas burner 26 is called Exhaust gases flow through the ball bed 25 and over the Exhaust pipe 28 exit with valve 29 open; for the Blowing in hot air, the valve 29 is closed, and valves 31 and 24 are opened; due to the im Reaction vessel 10 prevailing vacuum, the air can now enter generator 22 via lines 30 and 27 and is here on the heated ball bed 25 Brought temperature; the heated hot air then comes out via the connecting line 23 with the valve 24 open in the Reaction vessel 10 via the injection opening 17; is there it is appropriate that the connecting line 23 between the generator 22 and reaction vessel 10 is dimensioned as short as possible. The injection opening 17 in the reaction vessel is also like this dimensioned that at the internal pressure to be applied in each case or vacuum in the reaction vessel in each case best possible flow conditions for the entry of the Hot air exist.

Bei dem in Figur 4 dargestellten Ausführungsbeispiel ist eine Nutzung der Abwärme im Reaktionsgefäß eingerichtet, indem sich die Luftleitung 27 in die Einlaßleitung 30 und in eine Verbindungsleitung 32 zum Reaktionsgefäß 10 verzweigt, wobei die Verbindungsleitung 32 über ein Ventil 33 absperrbar ist und in diese Leitung ebenfalls ein Sauggebläse 34 eingeschaltet ist. Bei diesem Ausführungsbeispiel ist ferner das Ventil 24 nicht mehr in der Anschlußleitung 23 zwischen Generator 22 und Reaktionsgefäß 10 angeordnet, sondern befindet sich in der Luftleitung 27.In the embodiment shown in Figure 4 is use of waste heat in the reaction vessel has been established, by the air line 27 into the inlet line 30 and in a connecting line 32 branches to the reaction vessel 10, the connecting line 32 via a valve 33 is lockable and also in this line Suction fan 34 is turned on. With this In the exemplary embodiment, the valve 24 is also no longer shown in the connecting line 23 between the generator 22 and Reaction vessel 10 arranged, but is located in the Air line 27.

Bei diesem Ausführungsbeispiel erfolgt das Aufheizen der Kugelschüttung 25 bei geöffnetem Ventil 24 sowie geöffnetem Ventil 33 und laufendem Sauggebläse 34 durch das Einleiten der im Reaktionsgefäß 10 befindlichen heißen Gase, wobei nach dem Aufheizen der Kugelschüttung 25 das Ventil 33 geschlossen und das Ventil 31 in der Einlaßleitung geöffnet wird, so daß nun die Luft über die Luftleitung 27 in die aufgeheizte Kugelschüttung 25 eintreten und von hier aus über die Anschlußleitung 23 zum Reaktionsgefäß 10 strömen kann. Über das Ventil 24 ist bei beiden Ausführungsbeispielen in Abhängigkeit von dem im Reaktionsgefäß 10 herrschenden Unterdruck eine Regelung der in das Reaktionsgefäß 10 einzulassenden Menge an Heißluft gegeben.In this embodiment, the Ball bed 25 with valve 24 open and open Valve 33 and running suction fan 34 by the introduction of the hot gases in the reaction vessel 10, wherein after heating the ball bed 25, the valve 33 closed and the valve 31 in the inlet line opened is, so that now the air via the air line 27 in the heated ball bed 25 enter and from here Flow over the connecting line 23 to the reaction vessel 10 can. Via the valve 24 is in both Embodiments depending on the in Reaction vessel 10 prevailing vacuum regulation of amount of hot air to be admitted into the reaction vessel 10 given.

Claims (11)

  1. Process for the post-combustion of reaction gases produced during the decarbonization of molten steel in reaction vessels subjected to vacuum, in which an air current (18) is introduced into the reaction vessel (10) in counter-flow direction to the reaction gases (15), characterised in that the air current (18) introduced through an injection opening (17) disposed in the refractory lining consists of hot air with a temperature of between 800 °C and 1400 °C.
  2. Process according to claim 1, characterised in that the amount of air introduced is metered in such a way that the amount of reaction gases, calculated from the steel charge to be degassed, is burnt completely stoichiometrically.
  3. Process according to claim 1 or 2, characterised in that the introduction of air takes place over the whole period of the vacuum degassing of the molten steel.
  4. Process according to claim 1 or 2, characterised in that the introduction of air is limited to a first period of time for the vacuum degassing of the molten steel.
  5. Process according to claim 4, characterised in that the first period of time for the introduction of air is fixed at roughly half the period for the vacuum decarbonization of the molten steel.
  6. Process according to one of claims 1 to 5, characterised in that the introduction of air into the reaction vessel (10) is undertaken for every second charge.
  7. Process according to one of claims 1 to 5, characterised in that the introduction of air into the reaction vessel (10) is undertaken for every third charge.
  8. Process according to one of claims 1 to 7, characterised in that for the accelerated decarbonization of the molten steel oxygen is additionally blown into the steel bath via a lance insertable into the reaction vessel (10).
  9. Apparatus for carrying out the process for the post-combustion of reaction gases produced during the decarbonization of molten steel in reaction vessels subjected to vacuum according to claim 1, characterised in that a generator (22) serving to generate the hot air is connected to the reaction vessel (10) and that the generator (22) comprises a packed bed (25) of balls heatable by the supply of heat and consisting of a refractory material for the heating up of the air passed through the packed bed of balls (25) and subsequently introduced into the reaction vessel (10).
  10. Apparatus according to claim 9, characterised in that a separate burner (26) is provided for the heating up of the packed bed of balls (25).
  11. Apparatus according to claim 9, characterised in that for the heating up of the packed bed of balls the generator (22) is connected to the reaction vessel (10) in order to exploit waste heat.
EP96919573A 1995-05-26 1996-05-18 Process for post-combustion of reaction gases produced during the vacuum processing of steel and apparatus for carring out the process. Expired - Lifetime EP0832301B1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE19518900 1995-05-26
DE19518900A DE19518900C1 (en) 1995-05-26 1995-05-26 After-burning reaction gases arising during vacuum treatment of steel
PCT/DE1996/000902 WO1996037633A1 (en) 1995-05-26 1996-05-18 Process for post-combustion of reaction gases produced during the vacuum processing of steel

Publications (2)

Publication Number Publication Date
EP0832301A1 EP0832301A1 (en) 1998-04-01
EP0832301B1 true EP0832301B1 (en) 1999-03-24

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US (1) US6042633A (en)
EP (1) EP0832301B1 (en)
KR (1) KR19990021996A (en)
CN (1) CN1060526C (en)
AU (1) AU5809896A (en)
DE (1) DE19518900C1 (en)
WO (1) WO1996037633A1 (en)

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US20220412554A1 (en) * 2019-11-27 2022-12-29 Sms Group Gmbh Combustion of the CO in secondary metallurgical exhaust gas, with calorific value control and volume flow control

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Publication number Priority date Publication date Assignee Title
GB1014827A (en) * 1961-08-23 1965-12-31 Yawata Iron & Steel Co Method of accelerating decarburization of a molten steel by a degassing process using a vacuum container
FR1575991A (en) * 1968-07-08 1969-07-25
JPH01195239A (en) * 1988-01-29 1989-08-07 Kawasaki Steel Corp Method and apparatus for heating in vacuum degassing vessel
CA1337846C (en) * 1988-06-21 1996-01-02 Hiroshi Nishikawa Process for vacuum degassing and decarbonization with temperature drop compensating feature
JPH0737644B2 (en) * 1990-01-31 1995-04-26 川崎製鉄株式会社 Vacuum degassing device Splashing prevention method in exhaust gas duct
DE4130590C2 (en) * 1991-09-12 1993-11-04 Mannesmann Ag DEGASSING TUBE FOR THE VACUUM TREATMENT OF LIQUID STEEL
DE4221266C1 (en) * 1992-06-26 1993-10-21 Mannesmann Ag Method and device for inflating oxygen on molten metals

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US6042633A (en) 2000-03-28
DE19518900C1 (en) 1996-08-08
KR19990021996A (en) 1999-03-25
CN1190996A (en) 1998-08-19
EP0832301A1 (en) 1998-04-01
WO1996037633A1 (en) 1996-11-28
CN1060526C (en) 2001-01-10
AU5809896A (en) 1996-12-11

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