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Gas‐Liquid Mass Transfer in a Slurry Bubble Column at High Slurry Concentrations and High Gas Velocities
Author(s) -
Vandu C. O.,
van den Berg B.,
Krishna R.
Publication year - 2005
Publication title -
chemical engineering and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.403
H-Index - 81
eISSN - 1521-4125
pISSN - 0930-7516
DOI - 10.1002/ceat.200500151
Subject(s) - slurry , mass transfer , mass transfer coefficient , bubble , bubble column reactor , chemistry , gas to liquids , chromatography , superficial velocity , analytical chemistry (journal) , phase (matter) , materials science , chemical engineering , flow (mathematics) , composite material , gas bubble , mechanics , organic chemistry , physics , engineering
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 ϵ S ranged from 0 to 0.5. The experimental results obtained show that the gas hold‐up ϵ G decreases with an increase in slurry concentration, with this decrease being most significant when ϵ S < 0.2. k L a / ϵ G was found to be practically independent of the superficial gas velocity when U G > 0.1 m/s is taking on values predominantly between 0.4 and 0.6 s –1 when ϵ S = 0.1 to 0.4, and 0.29 s –1 , when ϵ 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.