PHYSICAL ABSORPTION OF CO2 AND PROPENE INTO TOLUENE WATER EMULSIONS

The physical absorption of CO2 and propene into toluene/water emulsion s is studied in a stirred cell and laminar film absorber. Experimental ly observed mass-transfer rates are compared to an absorption model, b ased on Higbie's penetration theory describing physical gas absorption into an emulsion. For all absorption experiments in a stirred cell ab sorber (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 ra tes in the laminar film absorber agree with the model simulations. Pro bable 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 an d the gravity force are parallel, this phenomenon does not probably oc cur significantly for absorption experiments in this absorber. The obs erved mass-transfer phenomena can be explained, at least qualitatively , from the occurrence of a thin toluene layer.