Numerical investigation of the reacting flows of three adjunct raceways in an industrial-scale blast furnace

Abstract

The raceway dynamics in ironmaking blast furnaces (BFs) are critical to determining energy efficiency and greenhouse gas emissions, but a comprehensive assessment of the dynamics of adjunct raceways at the particle scale has not yet been undertaken. In this study, an advanced reactive Computational Fluid Dynamics – Discrete Element Method (rCFD-DEM) approach is employed to simulate three adjacent raceways inside an industrial-scale BF. The typical in-furnace phenomena of a middle raceway between two adjunct raceways are captured from a 3D perspective for the first time. The raceway depths predicted are nearly 1.23 m, which are remarkably greater than those predicted by recent simulations, but closer to the experimental measurements. Then, the effects of blast velocity and temperature on raceway dynamics and combustion are quantified. After that, the key parameters for accurately simulating and measuring raceways are discussed. The results indicate that the suitable threshold voidage to accurately capture the raceway cavity should be 0.55, and the treatment using two adjunct raceways is much better for a natural formation of the raceway. The raceway dynamics predicted under different particle size distributions are considerably different with the deviation up to over 300%. The study forwards the particle-scale modelling of raceway dynamics and combustion to a practical 3D perspective using multiple raceways and clarifies the key parameters for the accurate simulation of raceway dynamics in BFs.