SIMULTANEOUS HEAT AND MASS-TRANSFER FOR MULTICOMPONENT DISTILLATION IN A WETTED-WALL COLUMN

A simultaneous heat and mass transfer model was applied to multicomponent distillation in a wetted-wall column. Experiments were carried out, using the benzene-toluene-ethylbenzene ternary system, in a wetted-wall column of 2.2 cm i.d. and 100 cm long equipped with special probes designed for simultaneous liquid sampling and temperature measurements. The experimental results show that the bulk liquid phase was saturated, indicating no resistance to mass transfer in the liquid film. Confirmation of the liquid phase saturation was made through a comparison of the experimentally measured liquid temperature with the calculated bubble point temperature. The average deviation between the measured and calculated temperatures was found to be 0.26°C. Individual mass transfer rates were evaluated locally by measuring compositions and temperatures as functions of column height and were compared to theoretical predictions using the exact film model solution of the Maxwell-Stefan multicomponent equations developed by Krishna and Standart. The comparison shows good agreement with average deviations of 15.76% for benzene, 23.09% for toluene and 23.23% for ethylbenzene. © 1979.