In a pulsed seive plate extraction column (PSEC) with a 150 mm diameter, a dynamic process and a conventional concentration profile measurement process were used to evaluate the mass transfer and axial mixing coefficients for the 30% TBP (in kerosene)/nitric acid/water system. The mass transfer direction was from the continuous phase to the dispersed phase. Experimental results indicated that the much simpler dynamic process could be reliably used in place of the concentration profile measurement process. A simple equation, (HTU)OC = KUc/σ(1-σ)n, was derived to calculate the 'true' height of transfer unit (HTU)oc (independent of column diameter) from the experimental mass transfer data and hydrodynamic characteristics in PSEC with different diameters while the mass transfer rate of the extraction system is controlled by the drop side resistance. The derivation of calculated values from experimental data was up to ±20%. The equation was tested in several other differential type extraction columns. It was shown that this equation could also be used to predict the 'true' height of transfer unit.; In a pulsed sieve plate extraction column (PSEC) with a 150 mm diameter, a dynamic process and a conventional concentration profile measurement process were used to evaluate the mass transfer and axial mixing coefficients for the 30% TBP (in kerosene)/nitric acid/water system. The mass transfer direction was from the continuous phase to the dispersed phase. Experimental results indicated that the much simpler dynamic process could be reliably used in place of the concentration profile measurement process. A simple equation, (HTU)OC = KUC/φ(1-φ)n, was derived to calculate the `true' height of transfer unit (HTU)oc (independent of column diameter) from the experimental mass transfer data and hydrodynamic characteristics in PSEC with different diameters while the mass transfer rate of the extraction system is controlled by the drop side resistance. The derivation of calculated values from experimental data was up to ±20%. The equation was tested in several other differential type extraction columns. It was shown that this equation could also be used to predict the `true' height of transfer unit.
