Liquid and Solids Entrainments in Slurry Bubble Columns

The liquid and solids entrainment using hydrocarbon fluids that mimic the Fischer-Tropsch reactor behavior and industrial catalysts are experimentally studied in a 4-in ID high pressure slurry bubble column and a 6-in ID ambient slurry bubble column. Paratherm NF heat-transfer fluid is used as the liquid phase, with ConocoPhillips aluminum oxide catalyst particles as the solids phase and nitrogen and air as the gas phase. The effects of superficial gas velocity, pressure, temperature, solids loading and freeboard height on the liquid and solids entrainment rates in the slurry bubble columns are examined. The operating superficial gas velocities, pressures, temperatures, solids loading, and freeboard heights vary by up to 0.55 m/s, 30 bar, 90 ⁰C, 25%, and 0.95 m, respectively. The study indicates that the liquid entrainment rate increases with superficial gas velocity, pressure, temperature, and solids loading. The solids entrainment rate increases with pressure and superficial gas velocity but decreases with temperature. At high superficial gas velocities, solids entrainment rate increases with solids loading. Liquid and solids entrainment rates remain almost unchanged when the freeboard height is bigger than a critical height. Correlations for the critical heights are developed for the liquid and solids respectively.