Scale-up of granular material flow in an agitated filter dryer

A challenge in agitated drying is to take information from the laboratory scale and use it to scale up the process to the manufacturing scale. In this study, we focus on scale-up of the granular flow in an agitated dryer by measuring the impeller torque which can be related to the particle shear stress. The shear stress can in turn be related to particle breakage. The impeller torque was independent of rotation rate and increased linearly with material bed height, and the particle size had an impact on the torque. The bulk friction coefficient and material cohesiveness were computed from a linear correlation between normal stresses and shear stresses in the particle bed. Torque predictions from the bulk friction coefficients exhibited good agreement with torque measurements. This work serves as an effective way to predict the granular flow on a larger scale using data from the laboratory scale.