Optimisation of the design of pulverised coal injection lances: From concept to full scale implementation at bluescope steel's BF6

Pulverised coal injection started at BlueScope Steel's Port Kembla blast furnaces in 2002. With significant economic advantages to reduce consumption of coking coal via increasing the quantity of pulverised coal injected to the blast furnaces, a three-dimensional numerical model of the blowpipe/tuyere/raceway has been developed. The model has been applied in various plant-specific investigations of blast parameters, and more recently in the development of alternate coal injection lance tip geometries. The designs with the highest potential for increasing coal burnout included swirl and high dispersive tip designs. The reduction in char load entering the furnace for the best performing alternate designs was due to an increase in coal dispersion compared with the conventional design. Afull-scale trial of the swirl lance design was carried out at Port Kembla's BF6 in mid-2008. The trial delivered promising results, with PCI rates maintained. This was despite unrelated changes to the coke ash content and the burden mix fed to the furnace, which would normally reduce furnace permeability.