alarcjet_orlando_nov2000-AmericanCombustionInc.PDFVIP

THEORETICAL AND EXPERIMENTAL STUDY OF SUPERSONIC OXYGEN JETS - INDUSTRIAL APPLICATION IN EAF B.Allemand (Air Liquide), P.Bruchet (Air Liquide), C.Champinot (Air Liquide), S.Melen (Air Liquide), F.Porzucek (SAM Neuves-Maisons) Introduction Oxygen use in EAF has increased a lot in the past few years and the trend will continue. Recent survey made by M. Birat1 from IRSID shows that average oxygen consumption was around 30 Nm3/t in EAF in 1998 and that this consumption will reach 40 Nm3/t in 2010. An other trend in EAF is to lower nitrogen level in EAF (to deliver a better quality steel); to achieve this, two points must be improved: Reduction of air entries in the furnace by trying to close partly the slag door Better foamy slag practice to avoid contact between air and liquid steel. Those two trends explain the emergence of new technologies for delivering oxygen into the steel bath. Recently, a number of technologies have been proposed with stationary wall mounted lances which can deliver oxygen at supersonic speeds to the molten steel bath. The novel feature of these lances is that the oxygen stream resists divergence as it is traveling in the furnace to the bath. The motivations to the steelmakers for using these lances in an EAF are as follows: Wall mounted lances allow decarburization to occur with the slag door closed. This should reduce the air ingress into the furnace, and save electrical energy. Injection is possible in several different locations. This can speed up the decarburization process and increase the homogeneity of steel bath temperature and chemistry. Lower maintenance costs are recognized because there are fewer or no moving parts associated with the wall-mounted injector. Wall mounted injectors greatly eliminate the need for replacing water-cooled lance tips or consumable pipe. A conventional lance manipulato