Numerical analysis of liquid flow in ironmaking blast furnace (BF) and its impact on BF performance

Various types of iron ores used in the blast furnace (BF) ironmaking process lead to different properties of the liquid flowing through the coke bed in the lower part, significantly influencing BF performance. This paper presents a numerical study of BF operations under different liquid conditions using a CFD process model. In this model, the force balance model that describes the liquid flow is modified to consider liquid viscosity and coke particle size explicitly. Using the model, the effects of different liquid viscosities corresponding to various iron ores are mainly studied based on a 5000-m³ industrial BF. These effects are also analyzed at various coke sizes. The numerical results show that as the liquid viscosity rises, the pressure drop first decreases and then increases, potentially leading to operation instability at high viscosities. These opposite trends of pressure drop result from the combined effects of increased liquid holdup and a thinned cohesive zone (CZ). Additionally, a higher liquid viscosity reduces the liquid temperature due to reduced solid-liquid heat transfer efficiency. The interaction between coke size and liquid viscosity complicates the above behavior, mainly through the influences on CZ thickness, liquid holdup, and solid-liquid heat transfer. This work provides insights to highlight the significance of liquid inside BF.