CFD simulation with experiments in a dual circulating fluidized bed gasifier

Gas and particles hydrodynamic behaviors were investigated in a pilot-scale cold-mode riser and a bubbling fluidized bed gasifier by means of experiment and computational fluid dynamics (CFD). Six different experimental sets were conducted in the cold-rig dual fluidized bed (DFB) at different gas velocities in both the riser and the recycle chamber aeration. A two-dimensional (2D) multi-fluid Eulerian model incorporating the kinetic theory of granular flows was applied to identify unsteady-state behaviors of the fluidized bed. The CFD model predicts well the solid circulation rate in the cold-rig DFB for all the six experimental runs. A discrepancy between experiment and simulation is observed in the axial solid holdup along the riser. The simulation results demonstrate that the cold-bed simulation can be used to predict the solid circulation rate for the hot-bed operation of the DFB gasifier. (C) 2011 Elsevier Ltd. All rights reserved.