ESSC & DUPLEX 2019

Numerical simulations like CFD and FEM have constantly evolved in the last decades and nowadays play an important role in the design and development of modern steelmaking converters. Although the flow inside the converter is highly complex and comprises a whole lot of physical phenomena like chemical reactions, heat transfer and the flow of gas bubbles in the liquid melt, it’s possible to capture major effects for the design of new converters with modern simulation tools. It is well known that the decarburization reaction is strongly influenced by the partial pressure of CO. To ensure a low partial pressure of CO a flat bath design with low bath height shows advantages. On the other side the bath height needs to be sufficient to ensure sufficient time for the reactions of the rising gas plume with liquid melt as well as proper mixing. Primetals Technologies has used extensive numerical simulations to compare various bath geometries for a 120t AOD to improve bath mixing and the interaction between slag and steel phase. As a result an optimized flat bath geometry could be found for both good decarburization and reduction reactions. Within its continues improvement initiative Primetals Technologies has also optimized its bath blowing equipment including the valve station, the process media supply as well as the automation and control concept. In this paper the most important aspects of numerical modelling the flow and mixing inside an AOD converter are described, followed by a detailed comparison of different vessel geometries and presentation of an optimized version.