(146c) CFD Simulation of Hydrodynamics in a Dual Fluidized Bed Gasifier

Gas-solid hydrodynamic behaviors in the riser and the bubbling fluidized bed (BFB) gasifier of a pilot-scale dual fluidized bed (DFB) are examined using a CFD code (Fluent, USA). Silica sand (solid phase) and air (gas phase) are used for the cold rigs in the DFB gasification system. Using the multifluid Eulerian-Eulerian model incorporated with kinetic theory of solid particles, a two-dimensional CFD model is applied to predict the unsteady-state behavior of the gas-solid flow. The interaction between gas and particles is considered in terms of the drag forces. Conservation equations of momentum and mass for each phase are solved using the finite volume method. The simulation results are first validated with experimental data obtained from the cold DFB gasifier. Then, the model is used to predict the hydrodynamic characteristics for the hot rigs in the gasifier on the basis of the temperature profile taken from experiment data.