CFD OF THREE PHASE BUBBLE COLUMN

Abstract

Bubble column (BC) or slurry bubble column (SBC) reactor has emerged as one of the most promising devices in chemical, biochemical and environmental engineering operations because of its simple construction, isothermal conditions, high heat and mass transfer rates, and on-line catalyst addition and withdrawal. The present work has been carried out to characterize the dynamics of three-phase flow in cylindrical bubble column, run under homogeneous bubble flow and heterogeneous flow conditions using CFD simulation. Investigation has been done to study the flow pattern of three-phase bubble column along with parametric studies. The simulations were performed for air-water-glass beads in a bubble column of 0.6m height, 0.1m i.d. and 0.05m sparger diameter to study the flow pattern. Eulerian-Eulerian . three-phase simulations with k-E turbulence for liquid phase were carried out using the commercial flow simulation software CFX-5.6, with a foCus on characterizing the dynamics properties of gas liquid solid flows. The effect of superficial gas velocity, solid loading, particle size, H/D ratio, sparger diameter and taperness on dynamics and flow behavior is studied computationally. For almost all the ranges of variable studied, the liquid phase holdup or solid phase holdup at the lower region differs significantly from the corresponding holdup at the upper region of bubble column this indicates that amount of dispersion in solid phase is not large. Reasonably, good agreement was obtained between the experimental data available in literature and simulation and % error. was found to be within + 20 %, and the flow pattern profiles obtained for various parametric studies appear to be sensible and logical. The results presented are useful for understanding the dynamics of gas liquid solid flows in bubble column and provide a basis for further development of CFD model for three phase systems.