CRITICAL GAS VELOCITY IN SLURRY BUBBLE-CO LUMN WITH SHORT SIZE DRAFT TUBE AT THE BOTTOM

Critical gas velocity for complete solid suspension is studied experim entally in a slurry-bubble column with a draft tube at the bottom, of which the height was less than half of gas-liquid dispersion height. E xperiments on the critical gas velocity are carried out with variation of diameters of bubble column and draft tube, length of draft tube, k ind of solid particle, and viscosity of liquid phase. Although the ten dency of the effect of the above mentioned variables on the critical g as velocity agrees with the previous work where the draft tube has app roximately the same height as the gas-liquid dispersion height, the es timated values by the previous work do not coincide with the data. The empirical equation for the critical gas velocty is presented by corre lating the present data.