Jet technology finds a home in a steel mill
31 Oct 2001
Praxair has signed a 10-year licensing agreement with the Brazilian steel company,Usiminas, one of the world's largest integrated steel producers, for the application of Praxair's patented CoJet gas injection technology.
Praxair estimates that the CoJet technology can save integrated steel producers up to $5 per ton of steel produced, depending upon the level of existing process technology and refining procedures of the mill.
The basic oxygen furnace (BOF) in a steel mill uses oxygen to rapidly refine molten iron into steel of a desired carbon and grade based on the required product specifications.
Praxair's CoJet system uses a lance and lance tip design with a patented injector nozzle that delivers coherent streams of oxygen up to five times the normal distance from the nozzle tip, while maintaining their original diameter and velocity.
As a result, coherent oxygen jets penetrate more deeply into the bath, providing more intense bath mixing and more efficient refining. The flame shroud maintains jet coherency by delaying the onset of turbulence. A programmable logic controller, skid and operation station provides complete process control and monitoring capability for the CoJet system.
The CoJet technology installed at a BOF can provide such benefits as improved yield, lowered dissolved oxygen (which improves product quality), increased manganese residuals (due to more uniform product quality), lowered aluminium additives (also due to improved product quality), and improved lance system efficiency (due to the advanced design and materials selection).
Depending on the specific conditions at a steel mill, a CoJet system installation will take an average of six months from contract signing to start-up. Praxair estimates that an average steel mill will see 100% return on its capital investment for installation of CoJet technology within the first year after start-up.
Praxair Metals Technologies, a separate business unit, is offering a licensing package which involves customisation of its patented CoJet technology to meet specific customer needs, in exchange for a royalty agreement in which Praxair will share equally in the savings over a ten year period.
Usiminas, with 8,400 employees, had sales in 2000 totalling $1.7 billion from the sale of 3.7 million metric tons of finished steel, manufactured from a total production of 4.5 million metric tons of steel. The company, headquartered in Belo Horizonte, Minas Gerais State in east-central Brazil, will install the CoJet technology at its Ipatinga facility.
