Restarting cold blast furnaces - using lance comprising coaxial tubes providing oxygen surrounded by fuel stream

摘要

Blast furnace which has gone cold is restarted by inserting in the iron notch and cinder notch a lance comprising inner and outer tubes with a space between, sealing the lance in each of the notches, injecting an O2 stream into the furnace through the inner tube and injecting the hydrocarbon fuel through the space between the tubes so that the hydrocarbon surrounds the O2 stream. The fuel/O2 ratio is varied so that the burden in the furnace is heated and then the cold iron is oxidised, the exothermic reaction occurs to raise the iron and slag to liquefying temps. and the lances are removed from the notches and the blast restored to the furnace. Restarting is rapid and lances do not tend to burn back whilst inserted in furnace. Tuyeres are left undamaged and break-outs are minimised.