CFD study of in-furnace phenomena of pulverised coal injection in blast furnace: Effects of operating conditions

A three-dimensional mathematical model of the flow and combustion of coal powder in a coke packed bed has been developed to simulate the complicated in-furnace phenomena of pulverised coal injection (PCI) in the raceway and the surrounding coke bed in an ironmaking blast furnace. The model includes the flow-thermal-chemical behaviours of two fuels: (i) coal powders; and (ii) coke solids. The typical in-furnace phenomena of the base case are obtained by means of this model in terms of flow and combustion behaviours of coal powder. An array of parametric studies are carried out to evaluate the effects of operating conditions under practical conditions, including blast conditions and types of cooling gas. The results show that these operating conditions play a limited role in improving the burnout at the endpoint of the raceway but a notable role in the recirculation region, i.e. over the raceway surface. Gas composition is sensitive to oxygen enrichment and use of oxygen as cooling gas. The results are then compared to the previous studies. The underlying mechanisms are explored. It is indicated that this study can provide more useful information for optimising the PCI operation in full-scale blast furnaces. (C) 2011 Elsevier B.V. All rights reserved.