HYDRODYNAMIC CHARACTERISTICS AND GAS-LIQUID MASS TRANSFER IN A DRAFT TUBE SLURRY REACTOR

Abstract

Fundamental characteristics of hydrodynamics and mass transfer have been measured in an air lift slurry reactor with a draft tube. The solid suspension capacity, i.e., the critical solid holdup, the gas holdup and the volumetric gas-liquid mass transfer coefficient were measured in the two draft tube columns of 0.1485 and 0.10 m in diameter. Four activated carbon beads ranging in size from 0.25 to 2.19 mm in average diameter were utilized as suspended solids in the experiments. The critical solid holdup in the draft tube slurry column is found to be much greater than that in the conventional bubble column. An empirical correlation is developed to account for the critical solid holdup behavior in the draft tube column. The gas holdup in the draft tube column agrees well with that in the bubble column. The overall gas-liquid mass transfer coefficient, k1awas measured by the oxygen probe method. The effect of solid holdup on k1a is found to be negligible in the present system. The empirical equation is devel...