GAS SEPARATION IN A 3-PHASE BUBBLE COLUMN

Slurry sorption of mixtures of gaseous components has been studied as a gas separation method in a semibatchwise operated 0.3 m i.d. bubble column. Activated carbon (solid), water (liquid), propane and ethene (gas) were used as model components. The liquid phase surrounding the solid particles acts as a "dynamical filter" for gaseous components due to a difference in solubility of the gases in the liquid. On its (internal) surface the solid phase accumulates gas molecules that diffuse through the liquid. By proper selection of liquid and solid it is possible to obtain a slurry with both a high selectivity and a high capacity for one or more of the gaseous components. The influences of superficial gas velocity and solids holdup on the selectivity of the separation are reported. A model is proposed for the description of the mass transfer in the column. The equations were solved numerically with a finite-differences method. The results are in good agreement with the experimental data. Empirical correlations are developed to correlate the bubble diameter, gas holdup and volumetric mass transfer coefficient. The axial dispersion of the liquid phase appears to be equal to that of the dispersed solids. © 1990.