Stagewise Modeling of Liquid-Liquid Extraction Column (RDC)


Chemical & Petroleum Engineering, Sharif University of Technology


Stagewise forward mixing model considering coalescence and redispersion of drops was used to predict the performance of Rotating Disc Liquid-Liquid Extraction Contactors. Experimental data previously obtained in two RDC columns of 7.62cm diameter, 73.6cm height and 21.9cm diameter, 150cm height were used to evaluate the model predictions. Drop-side mass transfer coefficients were predicted applying Handlos-Baron drop model and Olney's model was used to predict drop velocities. According to the results obtained the followings could be concluded: (1) If the height of coalescence and redispersion i.e.: could be estimated, the stage wise forward mixing with coalescence and redispersion model will predict the column height and efficiency with the acceptable accuracy, (2) The stage wise modeling predictions are highly dependent on the number of stages used when the number of stages is less than 10 and (3) Application of continuous phase mass transfer and axial dispersion coefficients (kc and Ec) obtained from the solute concentration profile along the column height will predict the column performance more accurately than the Calderbank and Moo-Young (for kc ) and Kumar-Hartland (for Ec) correlations.