The radial profiles of the lateral solids mass flux and the lateral solids
velocity were determined for FCC particles in a 7 m tall circulating fluidi
zed bed riser 0.14 m in diameter by applying a lateral flux probe and elect
rical capacitance tomography. The external solids mass flux was varied betw
een 148 and 302 kg/(m(2).s), while the superficial gas velocity was varied
between 3.7 and 4.7 m/s. Under these conditions, a dense bottom region and
an upper dilute region coexisted in the riser. Lateral fluxes in the dense
bottom region reached 100 kg/(m(2).s) at the wall, but fell to 14 kg/(m(2).
s) at the wall in the upper dilute region. At both axial locations, a net d
eposition of solids from the core to the annulus occurred, indicating that
fully developed flow was never established under these conditions. The late
ral fluxes in the bottom region were significantly larger than those found
in previous studies. It was further concluded that considering the lateral
solids flux to be only a function of solids concentration is an over-simpli
fication.