CFD Application on Hydrodynamic Studies of Multiphase gas-solids Flow in a circulating fluidized bed riser

摘要

This paper presents the CFD simulation of hydrodynamic behaviour of gas-solids in a cold pilot plant circulating fluidised bed riser system. It is quite important to have more accurate prediction of flow phenomena for better process performance given the rising cost of feedstock and even decreasing acceptable level of effluent contaminants. The development and use of predictive models for CFB riser reactors are necessary for most small and industrial process scale today. In this work, the relative amount of gas and the solid species as well as the interphase mass, momentum and energy transfer were taken into account. A CFB experimental data was used in these studies and simulation of flow behaviour in the riser using CFD (CFX 11.0) package using k-ε and SST model which are nearly same in values. The flow model is based on an Eulerian-Eulerian description of the phases where the kinetic theory for granular flow forms the basis for the turbulence modelling in the solid phases. In this study, both the gas and velocity profile follows a power law type expression; the gas velocity at the wall is zero. The model predictions are in agreement with the experimental data with FCC catalyst.