The classical penetration theory was corrected and then applied for the semi-theo-retical prediction of mass transfer coefficients k L a in a slurry bubble column operated in the homogeneous regime. The gas-liquid contact time was expressed as a ratio of bubble surface to the rate of surface formation. These terms were defined for the case of oblate ellipsoidal bubbles formed under homogeneous flow conditions. Six different liquid/solid systems (water/activated carbon, water/aluminium oxide tetralin/aluminium oxide, 0.8 M sodium sulfate solution/kieselguhr (diatomaceous earth),ligroin (petroleum ether)/polyethylene and ligroin/polyvinylchloride)were considered. By means of the same correction factor (a single function of Eötvös number)as derived previously for gas-liquid bubble columns, 85 experimental kL a values were fitted with a mean error of 19 %
