The effect of particle size and density on solids distribution along the riser of a circulating fluidized bed

A cold model of a CFB having a 0.120 m-ID and 5.75 m-high riser, was operat ed under a relatively wide range of gas velocity and solids mass flux. Four solids (two Ballotini, a silica sand and a spent FCC), belonging to groups A and B of Geldart's classification, were selected in order to separately investigate the effect of particle size and density on axial profiles of vo idage and on radial profiles of solids mass flux. Attention was focused, in particular, on the suspension density at the bottom and exit regions of th e riser. (C) 1999 Elsevier Science Ltd. All rights reserved.