C. G. J. Baker

Bubble characteristic in three phase fluidized beds

Abstract Bubble size and rising velocity in freely bubbling liquid-gas and three phase fluidized beds have been measured by means of movie photography. Three solids (1–6 mm), a variety of liquids, and air were employed as the three phases. Both bubble size and rising velocity were found to increase with gas velocity but were relatively insensitive to the liquid velocity, viscosity, and surface tension. At the high gas rates employed, the bubble characteristics were independent of particle size. Correlations are presented for calculating bubble size and rising velocity.

Oxygen mass transfer in bubble columns

Abstract The mass transfer of oxygen between air and water has been studied in a bubble column over wide ranges of liquid and gas velocity. An oxygen probe was used to map the steady-state liquid phase concentration of oxygen throughout the column. At any given point in the column, the oxygen concentration increased with gas velocity. Minima were observed in plots of concentration against liquid velocity. Two distinct absorption regions were observed. Close to the distributor the concentration decreased rapidly with height and volumetric mass transfer coefficients ranged from about 0.2 to 2.1 s−1. These high values were attributed to enhanced mass transfer due to turbulence induced by the liquid and gas jets in the grid region. In the bulk of the column, axial concentration gradients were much smaller and the mass transfer coefficients were up to two orders of magnitude lower than in the grid region.