Scale-Up Study on the Performance of Annular Pulsed Disc-and-Doughnut Columns

Abstract

Based on the previous work of the hydraulic, axial mixing, and mass-transfer performance of an annular pulsed disc-and-doughnut column (APDDC), the effects of scaling-up on its performance were studied in APDDCs with different annular space widths. The effect of scaling-up on holdup was discussed, and a more universal correlation was established. The effect of scaling-up on the Sauter drop diameter could be expressed by the previous obtained correlation. The effect of scaling-up on both the flooding holdup and throughput were mainly reflected in the correlation of the Sauter drop diameter. The equations of operating regimes were also independent of the scaling-up effect as demonstrated by experimental data. The scaling-up A c c e p t e d M a n u s c r i p t 2 effect on the axial-dispersion coefficient of the continuous phase, the mass-transfer coefficient, and the height of a transfer unit were also discussed.

Mass transfer in a pulsed and non-pulsed disc and doughnut (PDD) solvent extraction column

“…Results were predicted using Equation 5 and Equation 6 with c1=c2=4.33, which was proposed for pulsed columns. Liu (Liu et al, 2015(Liu et al, , 2016 studied the mass transfer coefficient in an annular PDDC in the operation range of Af from 11.5 to 14.8 mm/s. The experimental data were also predicted using Equation 5 and Equation 6.…”

Interfacial relaxation of droplets caused by mass transfer in a pulsed column

“…[15][16][17] Pulsed extraction columns have been widely used because of their many advantages, such as a small footprint, large processing flux, no rotating internal parts, and the ability to handle materials containing solid particles. 18 Because the interfacial tension is a key physical property in multiphase flow, 19 it is important for predicting hydraulic properties, such as the Sauter mean diameter (SMD) of liquid droplets, 20 flooding characteristics, 21 and dispersed phase holdup 22 in pulsed extraction columns. Studies have shown that under masstransfer conditions, dynamic changes in the interfacial tension occur, resulting in changes in the hydraulic behavior of the extraction devices.…”