McDonald, C.
[Contributor];
Koopmans, P.
[Contributor];
Böttcher, G.
[Contributor]
;
European Communities,
European Commission Directorate-General for Research
Bath stirring and injection of solids in the BOF using coherent jet technology
Description:
BOF coherent jet technology was invastigated by Corus, IEHK-RWTH and BOC, with financial support from the ECSC. The project aimed to improve BOF efficiency using inert, shrouded jets from the top lance. Research was conducted in: - nozzle design and characterisation, - physical modelling of gas and solids injection, - mathematical modelling of jet and bath mixing, and - hot laboratory and pilot plant trials. Gas and solids injection into a bath was investigated using mathematical modelling, physical modelling (water and mercury), hot laboratory tests and pilot plant trials. Physical modelling and jet characterisation results were used to validate mathematical models. Mathematical modelling showed that coherency is achieved by reducing the mixing layer between two free streams. This occurs if a high-velocity stream has a greater density than a low-velocity stream. Surface cavities were investigated using a coherent jet simulation lance. A minimum in-bath mixing time was observed, dependent on jet characteristics. Laboratory molten metal carburisation and desulphurisation showed that injecting in the unlinked state ensures rapid transfer of material to the bath, but linked injection gives faster mixing. The trade-off between mass transfer and bath stirring presents an optimisation problem. Laboratory tests and pilot plant trials established safe operating practices, giving confidence for full-scale plant trials. The coordinator and partners thank the ECSC and its officers for their support.