Volumetric mass transfer coefficient and gas hold-up in highly viscous liquid in bubble columns

Volumetric liquid phase mass transfer coefficients were measured by means o f desorption experiments of dissolved oxygen in several highly Viscous liqu ids in bubble columns. Gas hold LIPS were also measured by use of the same bubble Columns. These measurements were carried Out under the various condi tions of the column diameter, liquid depth and liquid viscosity in the rang e where the superficial velocity of the gas is less than 5 mm/s. The volumetric mass transfer coefficient was found to decrease with increas ing liquid depth, but it showed constant values if the ratio of the liquid depth to column diameter exceeded a certain value. From these results, a co rrelation equation which was applicable to a ide range of operating conditi ons was proposed. The gas hold-up was found to increase with increasing liquid viscosity, ind ependently of the liquid depth, and to be expressed well by the empirical c orrelation equation proposed in this work.