Gas‐Liquid Mass Transfer in a Slurry Bubble Column at High Slurry Concentrations and High Gas Velocities

The volumetric mass transfer coefficient k L a in a 0.1 m-diameter bubble column was studied for an air-slurry system. A C 9 -C 11 n-paraffin oil was employed as the liquid phase with fine alumina catalyst carrier particles used as the solid phase. The n-paraffin oil had properties similar to those of the liquid phase in a commercial Fischer-Tropsch reactor under reaction conditions. The superficial gas velocity U G was varied in the range of 0.01 to 0.8 m/s, spanning both the homogeneous and heterogeneous flow regimes. The slurry concentration ES ranged from 0 to 0.5. The experimental results obtained show that the gas hold-up EG decreases with an increase in slurry concentration, with this decrease being most significant when e S 0.1 m/s is taking on values predominantly between 0.4 and 0.6 s -1 when e S = 0.1 to 0.4, and 0.29 s -1 , when e S = 0.5. This study provides a practical means for estimating the volumetric mass transfer coefficient k L a in an industrial-size bubble column slurry reactor, with a particular focus on the Fischer-Tropsch process as well as high gas velocities and high slurry concentrations.

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