Solid-liquid mass transfer in sonicated agitated vessels with high concentration slurries

Process intensification of agitated slurry vessels requires improving solid-liquid mass transfer beyond that can be achieved with agitation alone. As ultrasound has been shown to enhance solid-liquid mass transfer, this study aims to investigate whether process intensification can be achieved under combined (agitation + ultrasonic irradiation) condition. Experiments were conducted involving high volumetric solids concentration (C V ) suspended at just off-bottom solids suspension (N JS ) condition in a 0.2 m diameter tank equipped with a turbine and an ultrasonic generator. The mass transfer experiments were conducted using ion-exchange (NaOH-cation resin) and desorption (phenol-polymeric resin) systems. Ultrasound was found to have no influence on mass transfer in the ion-exchange system for a C V range of 0.03–0.20 (volume solids/volume slurry). However, the rate and degree of mass transfer in the desorption system were higher under the (agitation + ultrasonic irradiation) condition compared to those under agitation-only condition. Under ultrasound irradiation, the degree of mass transfer in the desorption experiments increased with increasing time but did not show a clear trend with increasing C V . These results imply that the level of enhancement in solid-liquid mass transfer in agitated vessels due to ultrasound is dependent on the physical properties of the solid and liquid phases as well as C V .