Droplet-Resolved Modeling on Dispersion Kinetics of Desulfurization Flux in a Mechanically Agitated Ladle for Hot Metal Treatment

Insights into dispersed phases, such as droplets, and their distribution and evolution in a mechanically agitated ladle like Kanbara reactor (KR), which dramatically increases the contact area between phases/reactants and remarkably intensifies the rate phenomena, are of great significance to refining processes of steelmaking industries, but are still challenging and not fully understood. This work presents a droplet-resolved model (DRM) combined with a scaled-down water model experiment to investigate the dispersion behavior of desulfurization flux into the hot metal, wherein the DRM can directly acquire the small-scale dispersed droplets in the dispersion process and large-scale interface without employing any empirical relations. The study focuses include identifying the dispersion regimes, quantifying the dispersed phase, understanding their temporal and spatial evolution, and optimizing the operating/design parameters to intensify the desulfurization efficiency. Specifically, three dispersed regimes—non-dispersion, local dispersion, and emulsion/complete dispersion regimes—are first identified based on the experiments and numerical simulations. Further, after being validated by these experiments, the DRM model is applied to study a full-scale industrial KR, and two measures for quantifying the dispersed phases—the dispersion rate γ and the interfacial density B—are introduced. The simulation results revealed the developing dispersion process as three stages: non-dispersion, transition, and dynamic equilibria. Also, the effect of the impeller rotation speed, immersion depth, blade dimensions, amount and density of molten desulfurization slag on γ and B, and the spatial distribution variation of the dispersed phase are discussed. Finally, two new correlations for evaluating the dispersion rate and interfacial density are proposed for hot metal desulfurization industrial ladles with mechanically agitated.