Method for injection of a gas with an injection nozzle

摘要

Injecting gas into a liquid uses a supersonic injector (10) incorporating a Laval tuyere (20) arranged at a set distance above the bath. The dimensions of the tuyere are calculated as a function of the desired oxygen flow and jet speed, and the oxygen pressure at the tuyere inlet is such that the static pressure of the jet leaving the injector is essentially equal to the surrounding atmospheric pressure. For preference, the injector incorporates an annular channel (13) for the injection of natural gas and may be used in a burner mode at the start of the scrap melting stage. The oxygen injection speed is then subsonic.