Thermochemical modelling of the blast furnace raceway zone

Abstract

The blast furnace raceway zone is a cavity in the vicinity of the tuyeres where hot air enters the furnace. The thermochemical processes inside the raceway are critical for the overall blast furnace efficiency. They determine the reducing gas composition and provide the required energy, e.g., for heating up iron ore and coke particles or iron liquefaction. Despite of the raceway importance for the blast furnace process, only limited experimental data is available due to the harsh conditions (T > 2000 °C, p ≈ 5 bar(a), high dust load, etc.). Computational Fluid Dynamics (CFD) can be used to gain insights to the thermochemical processes. The main focus is on the thermochemical conversion of alternative reducing agents (ARAs), which are carbon carriers introduced via the tuyeres, while raceway shape and thermochemical coke conversion are also important. Modeling these complex processes poses various challenges, e.g., length scales from µm to m or time scales from nano seconds to hours. These challenges and possible modeling approaches will be discussed in the context of reactive multiphase flows.