We’re exhibiting at ICSOBA 2022 in Athens, Greece, Oct. 10-14. Please visit our booth to say hello and discuss your process modelling requirements with Dan Manché and Ab Rijkeboer, experts in Bayer process simulation.
Ab, representing Rinalco, will be presenting the paper “Advances in Process Simulation of Agglomeration in Bayer Precipitation”, co-authored by John McFeaters and Dan Manché of SysCAD. In this work, a new agglomeration kernel and practical calibration procedure is introduced, as well as a discussion on the state of the art of simulation of growth, agglomeration and nucleation processes.
Developing a Bayer precipitation circuit model with accurate predictive capability requires comprehensive physical models for the fundamental processes occurring and, importantly, a structured approach to tuning the model to available plant data. A new agglomeration size kernel has been constructed based on agglomeration kernels developed by René David et al. for different types of eddies within turbulence. The new kernel takes account of the fact that two types of eddies are of practical relevance to agglomeration in precipitation circuits, namely small laminar eddies whose behaviour is dominated by viscous forces and larger eddies whose behaviour is dominated by inertial forces. As well as simulating the chemical and physical processes underlying agglomeration, the kernel offers flexibility in its application due to the inclusion of various adjustable parameters. This facilitates model calibration for accurate prediction of particle size distribution (PSD) in the discharge flows from tanks in the precipitation circuit where complex particle interactions take place under a variety of hydrodynamic conditions. The kernel has been implemented into the Precipitator 3 unit model of the SysCAD process simulation software. A systematic procedure for calibration has been developed for obtaining the closest approach to the target PSD whereby various combinations of kernel parameters are tested with simultaneous tuning of constants for growth, nucleation, and agglomeration rates on their respective targets. Aspects of supersaturation, growth rate, nucleation rate and agglomeration rate are reviewed in the context of calibrating predictive established relationships.
ICSOBA 2022, the 40th International Conference and Exhibition is hosted by ICSOBA, the International Committee for Study of Bauxite, Alumina & Aluminium. The conference unites industry professionals from bauxite, alumina and aluminium producers, technology suppliers, researchers and consultants from around the world, with a focus on sustainable development.