Experimental Study of Volumetric Mass Transfer Coefficients in Slurry Bubble Column Reactor

Abstract

Scaling up of Fisher-Tropsh requires suitably accurate estimations of hydrodynamic and mass transfer parameters as a function of column size and slurry concentration. The present study focuses on gas holdup, volumetric mass transfer and local mass transfer coefficients in a slurry bubble column employing a C9-C11 Iraqi paraffin oil as a liquid phase, alumina and silica particles as a solid phase and oxygen was used as a gas phase because the properties of the paraffin oil are similar to those of Fisher-Tropsch wax under actual operating conditions in the industrial slurry bubble column and alumina and silica serve as carrier for the active cobalt catalyst utilized in the Fischer-Tropsch process. The experimental work was carried out using two rectangular (0.1 m length, 0.02 m width and 0.95 m height) and (0.1 m length, 0.02 m width and 2.6 m height) slurry bubble columns. The superficial gas velocity was varied in the range of (1-6 cm/s) for short column and (7-12 cm/s) for long column. For all experiments the height of liquid phase was maintained at (75 cm) for short column and (160 cm) for long column from the gas distributor and solid loading varied in 0, 5, 10, 15% vol. The experimental results showed that the gas holdup increases linearly with superficial gas velocity at both homogeneous and heterogeneous regimes but the rate of increasing is slower at the heterogeneous flow and also the volumetric mass transfer coefficient increases with superficial gas velocity for both regimes. And the results showed that the gas holdup and volumetric mass transfer coefficient decreased with increasing solid loading.