2014 Volume 28 Issue 3 Pages 366-376
Flow characteristics of a gas-solid spouted bed with a modified draft tube have been investigated experimentally. In this work, four different types of draft tubes were employed and spherically shaped silica gel particles having low particle density were used as the bed materials. The flow characteristics were compared with those obtained using spherically shaped glass beads. The results showed that the conical-cylindrical porous draft tube was the best option for gas-solid contact and solids circulation, and the gas flow rate through the annulus reached the level of a conventional spouted bed without a draft tube. Also, the minimum spouting gas velocity, bed pressure drop and gas flow rate through annulus for the silica gel particles were smaller than those for the glass beads. Although the silica gel particles descended in annulus faster than the glass beads because of high sphericity, the particle density of the silica gel was so small that the solids circulation rate was smaller than that for the glass beads.
