Three phase fluidized bed reactors are a common occurrence in the process industries and are used in processes such as slurry reactors, and ebullent beds. In spite of the technological importance of these reactors our understanding of these reactor are limited due to the complicated fluid dynamics, and subsequently the heat and mass transfer characteristics of these rectors.

In this contribution we review recent efforts to understand three phase gas-liquid-solid fluidization from a fundamental viewpoint, and report on our efforts to model the fundamental problem of the motion of a bubble in slurries, and the solid phase mixing induced by the motion of the bubbles [1, 2]. By using the Eulerian multi fluid model in ANSYS CFX and ANSYS Fluent, we study the dependence of the bubble rise velocity on the solids concentration and the solid phase mixing induced by the motion of the bubble. We compare our results with the recent VOF-DPM studies reported in [2]. The implications of these results for reactor modeling, as well as closures for the coarser dispersed multi fluid models are also discussed.

References

[1]. Solid phase hydrodynamics of three-phase fluidized bed reactors – A convective/dispersive phenonmenon, International Journal of Chemical Reactor Engineering, Vol 5, Article A3, 2007.

[2]. Numerical simulation of gas-liquid-solid flows using combined front tracking and discrete particle method, Chemical Engineering Science