Solid phase hydrodynamics of three-phase fluidized beds—A convective/dispersive mixing model

The main objective of this work was to develop a solid phase mixing model that followed not only the mixing extent, but also the overall mixing mechanism, i.e., the contribution of the convective onto the dispersive mixing mechanism. A non-invasive radioactive particle tracking (RPT) technique was used to estimate the model parameters and generate tracer curves at various axial positions. The proposed model follows the tracer data well compared to the axial dispersion model. It has the flexibility to represent various contributions of the convective onto the dispersive mixing mechanism observed in three-phase fluidized beds and it is linked to the bubble velocity distribution. The convective/dispersive model successfully followed the evolution of the extent of particle mixing and the overall mixing mechanism at various superficial gas and liquid velocities as well as reactor diameters.