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

Abstract

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 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 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.A c c e p t e d M a n u s c r i p t 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.

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

“…The physical properties and equilibrium distribution relationship of this system have been discussed in our previous work. [14] Operational procedure…”

“…[14] The reduction of mass-transfer surface area caused by the formation of dispersed phase layers on the discs and doughnuts was assumed to be constant, to establish a regressed model to calculate the mass-transfer coefficient for the extraction process, shown as Eq. 18.…”

“…16, in which the value of A c c e p t e d M a n u s c r i p t 16 The average values of the physical properties and the corresponding equilibrium curve slope were applied in the calculation [14] .…”

“…[9,10] A c c e p t e d M a n u s c r i p t 4 The air-purge method was chosen for the parametric measurement, and nine sampling points were set all over the active section to measure the holdup and the concentration profiles, as described in detail in our previous work. [13,14] Chemicals Water-nitric acid-30% tributyl phosphate (in kerosene) at equilibrium was used as the working system in the hydraulic experiments. Physical properties are listed in Table 2.…”

“…The concentration profile was then correlated with the axial-dispersion model (ADM) to calculate related parameters, in particular the axial-dispersion coefficient of the continuous phase (E c ) and the number of transfer units (N oc ) [14] .…”