Correlations for prediction of mass transfer coefficients in single drop systems and liquid-liquid extraction columns

Empirical correlations for the prediction of mass transfer coefficients for single drops are presented. Published experimental results for both circul ating and oscillating drops are considered. Correlation for the individual continuous-phase mass transfer coefficient, which is based on data from 596 measurements taken from 10 different groups of investigators, reproduces t he data with an average absolute error of 14.1%. This is then used to deter mine a correlating equation for the individual dispersed-phase mass transfe r coefficient on the basis of data for overall dispersed-phase mass transfe r coefficient taken from 21 sources. The average absolute value of the rela tive error in the predicted values of overall dispersed-phase mass transfer coefficient from the experimental points by using the correlations for ind ividual mass transfer coefficients is 24.5%. It is further shown that by al lowing for the effects of power input per unit mass and dispersed-phase hol d-up, the correlations for single drops can be extended to extraction colum ns. The correction factors required for this purpose have been obtained by using simulated values of overall mass transfer coefficients for pulsed per forated-plate, Karr reciprocating-plate, Kuhni, and rotating disc columns.