CFD Modeling of Gas-Liquid-Solid Fluidized Bed

Abstract

Gas–liquid–solid fluidized beds are used extensively in the refining, petrochemical, pharmaceutical,biotechnology, food and environmental industries. Some of these processes use solids whose densities are only slightly higher than the density of water. Because of the good heat and mass transfer characteristics, three-phase fluidized beds or slurry bubble columns have gained considerable importance in their application in physical, chemical, petrochemical, electrochemical and biochemical processing.This project report can be divided mainly into four parts. The first part discusses about importance of gas-liquid-solid fluidized bed, their modes of operation, important hydrodynamic properties those have been studied either related to modelling or experimental analysis and applications of gas-liquid-solid fluidized bed. The second part gives an overview of the methodology used in CFD to solve problems relating mass, momentum and heat transfer. Also comparative study of various CFD related software is given in this section. Third part contains the details about problem description and approach used in FLEUNT to get the solution. Finally results of simulation and comparison with experimental results are shown. The experimental setup was a fluidized bed of height 1.88m and diameter 10cm. The gas (air) and liquid (water) is injected at the base with different velocities while taking glass beads of different diameters as solid bed. The variables to be investigated are pressure drop, gas holdup and bed expansion. It is required to verify the solutions of simulation by comparing it with experimental results and then rest of the prediction can be done instead of carrying out the experiments. In this way it helps to save the experimental costs and prevents from risk of wastage of resources.