Untersuchungen zur Erhöhung der Bogenspannung in Elektrolichtbogenöfen durch Einblasen mehratomiger Gase

Methane injection into the arcs of electric arc furnaces has been shown on pilot scale to lead to a remarkable arc voltage increase at constant arc current and arc length. The investigations have been concerned with the associated metallurgical effects making use of a gas-tight 150-kg arc furnace operated with two AC plasma torches. The test runs with bored graphite electrode in DC-mode with a bottom electrode in this furnace confirmed the power increase observed during methane injection. The carburization slowly occurring when 6 % CH4 was injected into the argon atmosphere of the furnace could be avoided by adding minor amounts of CO2. A slag layer decreased mass transfer rates without noticeably affecting heat transfer. Manganese loss by evaporation was measured to investigate the influence of power increase and slag layers. From the results, an increase of 200 K was concluded for the melt surface temperature when CH4 was added to pure argon. Methane injection into the arcs proved to accelerate nitrogen removal considerably. Starting with an intentionally high nitrogen content of about 200 ppm, the nitrogen removal rate was found to be slowest with pure argon plasma arcs, faster with 90 % Ar + 10 % H2, and the fastest with 95 % Ar + 5 % CH4 reaching final contents of less than 20 ppm of nitrogen. Based on thermodynamic calculations, the denitrogenation reactions appear to take place via atomic nitrogen in pure argon plasma, via NH3 in Ar + H2 and via HCN in Ar + CH4. Several suggestions about how to prevent the possible carbon deposition in the graphite electrode hole due to injection of 95 % Ar + 5 % CH4 through the hole have been discussed.

Grantor dc:publisher

Publikationsserver der RWTH Aachen University

Year dc:date

2003

Author dc:creator

• Spirin, Denis

Contributors dc:contributor

• Neuschütz, Dieter

• info:eu-repo/classification/ddc/660
• Lichtbogenofen
• Gleichstromlichtbogen
• Spannungsänderung
• Leistungssteigerung
• Molekulares Gas
• Blasverfahren
• Technische Chemie
• Leistungserhöhung
• Methaneinblasen in den Lichtbogen
• Entstickung

Statement dc:rights

• info:eu-repo/semantics/openAccess

Language dc:language

ger

Identifier

https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-121040%22

OAI identifier oai:identifier

oai:publications.rwth-aachen.de:59235