Characteristics of Gas Flow in Laval Nozzle with Sub-hole for RH Multi-function Treatment

Hiraoka, Teruyoshi; Ohnuki, Kazuo; Fujii, Hironobu; Fukuda, Kazuma; Hoshijima, Yousuke

doi:10.2355/tetsutohagane1955.89.2_244

Cited by 2 publications

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“…The experimental apparatus was a 100-ton scale RH degasser as shown in figure 1. The multifunctional lance, described in the previous study [2], was inserted through the seal from the upper part of the vacuum vessel, and continuous measurements were made for: volumetric flow rate of oxygen and LNG; temperatures of lance cooling water, waste gas, and refractory surface and height of the lance. The experiment was conducted at three standards of LNG flow rates: 72 Nm 3 /h, 182 Nm 3 /h, and 239 Nm 3 /h, and and lance charge length of 3.8 m, 2.8 m, and 1.8 m. The oxygen flow rate in all cases was 2.3 times the LNG flow, and waste gas was released into the atmosphere through a dipping duct in the lower part of the vacuum vessel.…”

Section: Experimental Methodsmentioning

confidence: 99%

“…The authors investigated the possibility of avoiding such problems by injecting oxygen through the long divergent part of a Laval nozzle, and injecting LNG through a secondary nozzle installed near the outlet, thus forming a flame either near the nozzle outlet to raise the temperature of the refractory, or on the surface of the molten steel to prevent temperature decrease of the steel [1]. In this study we report the experimental results of application in a 100-ton piece of equipment on the changes in temperature of the refractory surface and molten steel, when mixed gas of LNG and oxygen were injected into the vacuum vessel during non-decarburization period using a multifunctional lance [2]. 474…”

Section: Introductionmentioning

confidence: 99%

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Use of LNG-Oxygen Gas Mixture in RH Degassing Unit

Hiraoka

Ohnuki

Fujii

et al. 2003

steel research international

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Mixed gas of liquefied natural gas (LNG) and oxygen was injected into the vacuum vessel during non-decarburization period using a multifunctional lance. Tthis study reports the experimental results when applying this process in a 100-ton piece of equipment and reports the changes in temperature of the refractory surface and molten steel. Using a multifunctional lance allowed heat supplementation by injecting LNG-oxygen mixed gas into the vacuum vessel of a RH device and then burning the gas near the outlet of the injection nozzle. The following was found: The minimum surface temperature required so that the skull would not adhere to the RH vessel was calculated as about 1643K (1370°C). When the interior of the RH vacuum vessel was preheated with a multifunctional Janee so that the temperature would be higher than this, skull adhesion to the vessel did not occur. Calculation of heat balance for burning under atmospheric pressure showed that about 70% of the heat quantity of burning was supplied to the refractory. When mixed gas was burned during the RH process. it was shown from the temperature change of molten steel that about 52% of the burning heat was transferred to the steel. Heat quantity removed through lance cooling water was proportional to the charge length of the lance, and emissivity E was equivalent to heat transfer quantity of 0.38. Einsatz vonMischgas aus Flussigerdgas und Sauerstoff in RH-Vakuumanlagen. Mischgas aus FIOssigerdgas (LNG) und Sauerstoff wurde in ein VakuumgefaB wahrend der nicht-entkohlenden Phase mit einer Multifunktions-Lanze eingeblasen. Die vorliegende Arbeit zeigt die Versuchsergebnisse fur die Anwendung dieses Verfahrens in einem 100-t-GefaB und erlautert die Temperaturveranderungen in der Feuerfestzustellung und im Stahlbad. Mit der Multifunktions-Lanze konnte durch Einblasen von LNG-Sauerstoff-Msichgas und nachfolgende Verbrennung des Gases nahe der Ausflussi:iffnung in das RH-VakuumgefaB Zusatzwarme eingebracht werden. Folgende Zusammenhange wurden gefunden: Damit sich keine Baren am RH-GefaB bildeten, musste die Oberflachentemperatur mindestens 1643 K (1370 °C) betragen. Wenn das RH-GefaB von innen mil der Multifunktions-Lanze vorgeheizt wurde, bildeten sich keine Baren. Die Berechnung der Warmebilanz fur die Verbrennung unter atmospharischem Durck zeigte, dass etwa 70% Warmemenge aus der Verbrennung auf die Feuerfestzustellung Obertragen wurde. Bei Verbrennung von Mischgas wahrend des RH-Prozesses wurde durch die Temperaturanderung des Stahlbades deutlich, dass etwa 52% der Brennwarme auf die Stahlschmelze Obertragen wurde. Die Warmemenge, die durch das LanzenkOhlwasser entzogen wurde, war proportional zur Chargierlenge der Lanze, und das Emissionsvermi:igen E war einem WarmeObergang von 0,38 aquivalent.

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Section: Experimental Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%