Numerical and Physical Modeling of Steel Desulfurization on a Modified RH Degasser

This study presents a new approach for RH degasser for desulfurization purposes. The modified RH has a short down leg length, so the steel flowing through this leg is discharged above the slag–metal interface. Physical and mathematical modeling were carried out and the results show that a large slag dispersion into steel can be achieved, so an efficient desulfurization is expected for this modified reactor. In the physical model as well as in computational fluid dynamics simulations, water or a saline solution were used to mimic the steel similar phase and three kinds of oils to emulate the slag. It was observed that as circulation rate is increased, the emulsification increased too. Additionally, for large phase density difference it was observed that oil dispersion is already intense, but it is concentrated nearby the down leg flow. CFD simulations were applied to RH industrial unit too, and as expected, a large slag entrainment into steel is observed and sustained. The dispersed phase flows nearby the steel jet coming from down leg. Furthermore, this modification on RH does not compromise the main RH functions since no change on circulation rates and mixing times was observed.