A Computational Fluid Dynamics-Thermodynamics Coupled Approach to Simulate Desulfurization in Ladle Furnace Based on Interface Equilibrium Assumption

This study proposes a coupled computational fluid dynamics and thermodynamics model based on the assumption of interface equilibrium at the steel-slag interface to simulate the desulfurization process in a ladle furnace. The species transport equation is solved to analyze the kinetic behavior and chemical content variation in the melt. The sulfur distribution ratio is calculated based on the slag sulfide capacity and oxygen activity. Subsequently, the solutions are coupled by introducing the species transfer and source terms generated by comparing the initial and predicted thermodynamic equilibrium states at the steel-slag interface cell. The model is validated by experimentally comparing the sulfur content. Furthermore, the model is applied under different kinetics and thermodynamics conditions. With an increase in the gas flow rate, the in-phase effective diffusion coefficient increases, but the number of interface cells involved in the sulfur transfer process decreases. The complex relationship between the desulfurization process and the gas flow rate results from the mutual antagonism between these two factors. Moreover, the study findings demonstrate that a higher slag basicity enhances the calculated sulfur distribution ratio and final desulfurization ratio.