The physical absorption of CO2 and propene into toluene/water emulsions is studied in a stirred cell and laminar film absorber. Experimentally observed masstransfer rates are compared to an absorption model, based on Higbie's penetration theory describing physical gas absorption into an emulsion. For all absorption experiments in a stirred cell absorber (toluene fractions and stirring rates), experimentally observed mass-transfer rates are considerably higher than the rates predicted by the absorption model. Moreover, the absorption rate decreases with increasing stirring rate, whereas no influence of the stirring rate is predicted by the absorption model. In contradiction to the absorption experiments in a stirred cell absorber, the observed mass-transfer rates in the laminar film absorber agree with the model simulations. Probable existence of a very thin toluene layer is observed on top of the emulsion for the stirred cell experiments, likely due to minor phase separation. Since in the laminar film absorber gas-liquid interface and the gravity force are parallel, this phenomenon does not probably occur significantly for absorption experiments in this absorber. The observed mass-transfer phenomena can be explained, at least qualitatively, from the occurrence of a thin toluene layer.
Littel, R. J., Littel, R. J., Versteeg, G., & van Swaaij, W. P. M. (1994). Physical absorption of CO2 and propene into toluene/water emulsions. AIChE journal, 1994(40), 1629-1638. . https://doi.org/10.1002/aic.690401005