Dispersion Characteristics in a Counter-Current Microstructured Slurry Bubble Column and Its Analysis Based on the Turbulence and Circulation

Abstract

The slurry bubble column has gained the attention of researchers over the years because of its wide application in various processes in the chemical and mineral industries. This work aims to quantify the degree of axial and transverse slurry dispersion in a counter-current microstructured slurry bubble column within the ranges of particle concentration of 0.5–3.0 wt %, particle size of 63–408 μm, superficial gas velocity of 0.011–0.074 m/s, and slurry velocity of 0.018–0.058 m/s. The residence time distribution (RTD) technique by online conductivity measurement was used to study the dispersion phenomena at different axial and transverse positions in the column. The axial and transverse slurry dispersion coefficients were found within the ranges of 9.12–137.23 and 12.63–141.83 cm2/s, respectively. Both the coefficients increase with the superficial gas and slurry velocities and the particle diameter but decreases with the particle concentration. The transverse slurry dispersion coefficient was 3.35–38.79% higher than the axial slurry dispersion coefficient. A model was developed to interpret the intensity of the dispersion based on liquid turbulence and circulation. The dispersion due to circulation strongly depends on the slurry velocity relative to the superficial gas velocity. The degree of dispersion was also analyzed by the velocity distribution model. The present study gives insight into process intensification and modeling of the counter-current slurry bubble column.