(608e) Development of a Lab-Scale Pulsed Column for Observing Hydrodynamic Phenomena

Pulsed columns are a classical technology used to perform two-phase separations – typically liquid-liquid extractions – in several different applications, including rare mineral recovery, nuclear reprocessing, and other solvent-enabled chemical separations. The general principle is to flow two immiscible liquid phases countercurrent to each other through a column and superimpose a pulsating flow onto one of the flowing liquids to encourage droplet breakup and, consequently, more efficient mass transfer between the phases. The column typically has an internal geometry to assist with the dispersion of droplets, such as a packed bed, a disk-and-doughnut configuration, or periodically spaced sieve plates. In the United States, pulsed columns have been used for nuclear reprocessing at industrial scale, but very few smaller columns are in operation that can perform solvent extractions relevant to nuclear applications.

Scaling a pulse column down contains inherent challenges arising from the impact of wall effects, the generation of small amplitude pulsations, and short liquid residence times. A lab-scale prototype system has been designed and assembled for two purposes: (1) investigation of hydrodynamic phenomena using various aqueous/organic fluid permutations; and (2) collection of performance data to assist with the design of a future lab-scale apparatus (of similar scale) for radiological service. The design and scaling of the lab-scale prototype will be discussed, along with a presentation of initial experimental data collected using simple aqueous/organic two-phase systems.