The pulverized coal injection (PCI) is widely utilized in the iron-making blast furnaces for its economic and environmental advantages. However, due its complexity, flow dynamics and chemical kinetics of PCI inside the raceway has not been well understood. Combustions of PCI and coke inside the raceway can be influenced by tuyere operation parameters. In this paper, a comprehensive three dimensional (3-D) multiphase flow computational fluid dynamics (CFD) model was utilized to investigate the PCI and coke combustion in the lower part of a blast furnace. Systematic parametric studies were conducted to analyze the effects of the natural gas injection, coal injection, PCI rate, and oxygen enrichment on the combustion performance, which include coal burnt-out rate, coke consumption rate, raceway shape, raceway temperature and etc.

A blast furnace is a reaction vessel in which iron ore is converted to molten iron. High rate pulverized coal injection (PCI) into a blast furnace (BF) is an existing process that is known to decrease the amount of coke in the ironmaking process. Natural gas co-injection with pulverized coal increases the burnout and devolatilization rates of pulverized coal. Also, hydrogen produced from natural gas combustion is a powerful reducing agent of iron (III) oxide, releasing pure iron that trickles down and is eventually removed through the taphole. Due to the inherent complexity of the blast furnace ironmaking process, numerical simulation can prove to be quite difficult. This paper describes a three step methodology for modeling blast furnace combustion, and its application to a furnace in operation at USSC Hamilton Works.