Pseudo two-dimensional modeling of sediment build-up in centrifuges: A compartment approach using compressional rheology



Both a new modeling approach and new experimental data for the sediment build-up in centrifuges are presented. In semibatch apparatus, the suspension is continuously fed to the centrifuge, separating the particles inside the rotor and discharging the clarified liquid. The solid phase is removed once the capacity of the centrifuge is reached. The solids fraction of the sediment depends on the rheological properties of the cake. The sediment growth and consolidation throughout the process can be calculated using a pseudo two-dimensional approach that takes into account particle-size dependent settling, sediment compressibility, the centrifugal force field, and the geometry of the bowl. The predictions of the separation behavior and the particle-size distributions of the sediment and overflow are compared with experimentally obtained results, showing improved accuracy when compared to simpler models. The model presented is applicable to all solid-bowl centrifuges without conveying systems. © 2013 American Institute of Chemical Engineers AIChE J, 59: 3843–3855, 2013