Mass transfer and hydrodynamic studies in a 50 mm diameter centrifugal extractor

• Mass transfer studies were conducted at different operating conditions.
• Hydrodynamic studies were conducted for determining operating region.
• Specific interfacial area for mass transfer was measured by d32 technique.
• Non-ideality analysis, with pulse tracer experiments in aqueous and organic phases, was done.
• Comparison of pulse and step responses was performed for aqueous phase.

Centrifugal extractor is a preferred device for process intensification in solvent extraction. The complexities of high radiation damage to solvent and resultant degradation of solvent performance also necessitate the need for fast contactors like centrifugal extractors in the nuclear fuel recycle operations. In this study, mass transfer performance as well as hydrodynamic characterization was reported for a 50 mm diameter annular centrifugal extractor. Mass transfer studies included extraction and stripping experiments with solvent-aqueous pair of 30% Tri-n-butyl phosphate/n-dodecane and aqueous nitric acid solutions for different operating conditions like rotor speed, combined throughput and phase flow ratios. Flooding zone was characterized. Dispersed-phase holdups in annular as well as rotor regions and interfacial area for mass transfer were measured at different operating conditions. Non-ideal effects were studied by conducting residence time distribution analysis using aqueous phase as well as organic phase pulse tracer experiments. Various models like dispersion and tanks-in-series models were applied to experimental data. The contactor in study, was approximated as N number of tanks in series with a finite dead volume.