화학공학소재연구정보센터
Chemical Engineering Science, Vol.65, No.5, 1678-1693, 2010
Rotating fluidized bed with a static geometry: Guidelines for design and operating conditions
Computational fluid dynamics (CFD) simulations of the hydrodynamic behavior of rotating fluidized beds in static geometry (RFB-SG) are carried out for gas-solid flows. The rotating motion of the reactor bed is induced by the tangential injection of the gas along the circumference of the fluidization chamber. Steep gradients in the gas velocity fields both in radial and tangential direction generate turbulence. The radial and tangential drag forces fluidize the particle bed in both radial and tangential direction. An Eulerian two-fluid model is used. Gas phase turbulence is accounted for by a k-epsilon model adapted for rotational flows. The RFB-SG simulations provide guidelines for a design and operation with a high efficiency in gas-solid momentum transfer, excellent gas-solid separation and limited solids losses. Hydrodynamic variables like the centrifugal force, the injection pressure, the radial and tangential slip velocities, solids hold-up are calculated for both polymer particles (300 mu m, 950 kg/m(3), Geldart Group B) and glass beads (70 mu m, 2500 kg/m(3), Geldart Group A) to allow for a comparison among different fluidization chamber designs. Unstable bed behavior, like slugging and channeling, is also numerically predicted. (C) 2009 Elsevier Ltd. All rights reserved.