Study of Axial Solid Concentration Distribution in Slurry Bubble Columns

Abstract

The axial distribution of solid concentration was studied in semibatch slurry bubble columns. Tapered slurry bubble column (TSBC) and cylindrical slurry bubble column (CSBC) have been used in this study. Air, sodium chloride (NaCl) aqueous solution of concentration 0.15 M, and quartz sand, were represented gas, liquid and solid phases, respectively. The superficial velocity of gas was varied from 2.5 to 10 cm/s. Quartz sands with a mean diameter of 120 µm were used in the concentrations of 3,5,10 & 20 vol. %. Influences of gas velocity and solid loading on longitudinal profile of solid concentration were investigated. It was observed that the longitudinal distribution of solid concentration tends to be more uniform as superficial velocity of gas or solid loading increased. Under the same operation conditions, experimental results showed that TSBC offered more uniform distribution of solids along the column. The observed axial concentration distribution of solid particles in tapered slurry bubble column was analyzed on the basis of precipitation-dispersion model. The model successfully predicts the axial concentration distribution for narrow-sized range of solids systems in TSBC. Empirical correlation for the solid dispersion coefficient for solid particles in tapered slurry bubble column was proposed.