PREDICTION OF POINT EFFICIENCY FOR SIEVE TRAYS IN DISTILLATION

A new semiempirical model for the prediction of the number of mass-transfer units, hence tray efficiency, for distillation has been developed. The interfacial area of sieve tray dispersion is estimated by the Levich theory, and the mass-transfer coefficients are determined by the penetration theory. Two constants that are required to complete the model were obtained by fitting the model to the tray efficiency data of cyclohexane/n-heptane mixtures published by Fractionation Research Inc. (FRI). The predicted efficiency and percent liquid-phase resistance are in good agreement with the experimental values for ethylbenzene/styrene published by Billet and additional data from FRI.