"Bayer Process Autoprecipitation Modelling in Thickeners"
Bayer Process; autoprecipitation; Alumina; thickening; gibbsite reversion.
Most Bayer refineries monitor carefully alumina losses. One of the prominent effects that cause it is auto precipitation in the clarification circuit. This thesis proposes a conceptual model for the representation of the process nuances, considering settler solids profile and composition, and the uneven fluid flow behavior of a vessel of this type.
The model consists in discretization of decanter zones and representation of mixing, reaction, and splitting. It is proven to be at zero degrees of freedom independently of the composition detail on liquor and solids composition through a generalized degrees of freedom analysis for an undefined number of components and stages. The effect of model parameters such as number of stages, feed stream position, and mud bed level on the model response and stability is analyzed so to propose an ideal range of numerical modelling conditions.