Axial Mixing and Mass Transfer Performance of an Annular Pulsed Disc-and-Doughnut Column

The annular pulsed disc-and-doughnut column (APDDC) is an important type of extraction equipment in the PUREX process, which has been used in several commercial reprocessing plants. As there are few mass transfer experimental results reported in the literature, the axial mixing and mass transfer performance of an APDDC was studied for both extraction and stripping processes in the present work. Two parameters in the axial dispersion model (ADM), namely, the axial dispersion coefficient of the continuous phase and the number of mass transfer units, were regressed by correlating ADM with experimental concentration profiles. The influence of flow rate and pulsation intensity on these parameters was also investigated. Models developed for the PDDC were tested for correlation with APDDC experimental data and suitable models and conditions were determined. The height of a mass transfer unit was also calculated, which highlights the impact of axial mixing on mass transfer performance. Moreover, the influence of internal wettability on mass transfer performance was discussed.