Cocurrent gas-solid downflow fluidized bed (downer) reactors: IV hydrodynamic modelling

A comprehensive review for the hydrodynamic modelling of gas-solid two-phase flow in both risers and downers is presented in this paper. These hydrodynamic models for risers were classified as four types : ( I ) one-dimensional model; ( II ) core-annulus model; ( III ) tow-dimensional model; and ( IV ) multi-scale energy minimization model. Two kinds of hydrodynamic models, a one-dimensional hydrodynamic model and a two- dimensional turbulent model deduced from the fundamental dynamic theory, are also applied to predict the flow behaviors in downer reactors. The modelling results provide the theoretic basis for design, scale-up and optimization of downer reactors.