DISTRIBUTION OF AXIAL VOIDAGE IN THE RISER OF A CIRCULATING FLUIDIZED-BED

Experimental data on the voidage profile in the riser of a shallow cir culating fluidised bed have been reported. Four different sizes of lim estone and one each of bauxite and sand have been used in the investig ations. The air velocity in the riser ranged between 220-998 cm/s and that in the slow bed varied over 30-46 cm/s. The solids mass flux was of the order of 6-15.13 kg/m2 s. The voidage distribution curves sugge st the existence of a top region of dilute phase and a bottom section of dense phase, with a point of inflection in between. Based on the da ta, two correlations have been proposed for the dense and dilute phase s, both of them showing excellent agreement with the observed data.