A novel approach for measuring particle settling and settled bed build-up velocities in concentrated slurries using electrical resistance tomography

Electrical Resistance Tomography (ERT) has been used to detect different phases based on differences in conductivities in multiphase systems. For the first time, ERT is used in this work to study solids settling and settled bed build-up velocities in a slurry of glass particles and glycerol solution. It measures the particles' position via mixture conductivities, which determine solids concentration at different heights. Development of the solids settling velocity model relies on the movement of particles instead of tracking the solid-liquid interface. Experimental solids settling velocity value decreases with increasing solids concentration and liquid viscosity, agreeing with estimations from Richardson and Zaki's model. The settled bed build-up model uses mass balance and ERT data to predict build-up velocity, which increases with increasing solids concentration and decreasing liquid viscosity. Results demonstrate that, as a direct and non-invasive method, ERT could simultaneously measure the solids settling and settled bed build-up velocities in slurries.