METHOD FOR INJECTION OF GAS WITH INJECTION NOZZLE

摘要

PROBLEM TO BE SOLVED: To provide a nozzle for injecting a gas such as oxygen into a molten metal bath accommodated in a metal container. SOLUTION: A supersonic injector (10) is disposed in an electric arc furnace. This supersonic injector has a so-called Laval nozzle (20) disposed above the bath with a predetermined distance therefrom. The dimension of the nozzle (20) is calculated as a function of a desired flow rate of oxygen and a desired speed of jet. The pressure of oxygen at the inlet of the nozzle (20) is set so that the static pressure of the jet at the outlet of the injector (10) is substantially equal to the atmospheric pressure. More preferably, the injector has an annular channel (13) for injecting natural gas, and is used in a burner mode when scrap iron starts to melt. The oxygen speed is subsonic.