Representative shear rate for particle agglomeration in a mixing tank
Journal
Chemical Engineering Research and Design
Journal Volume
171
Pages
73-79
Date Issued
2021
Author(s)
Abstract
Polystyrene particles were dispersed in glycerol solution containing sodium chloride. The orthokinetic agglomeration process of the particles was observed in a mixing tank agitated by a six-blade Rushton turbine. It is found that the median diameter of agglomerates was initially increased and asymptotically approached a constant value. Bimodal particle size distributions were obtained within all of the experimental conditions and the stable size of produced agglomerates was independent of the rotational speed of the impeller. On the other hand, the amount of produced agglomerates was increased as the increase in the rotational speed of the impeller. Considering the experimental results, the population balance equation of a mathematical model to describe the evolution of the agglomerates was simplified. Then a representative shear rate taking into account the shear history of individual particles was proposed and its applicability was evaluated. It is showed that this shear rate is useful to predict agglomeration behavior of particles and a conventional representative shear rate in a mixing tank is overestimation. ? 2021 Institution of Chemical Engineers
Subjects
Mixing tank
Particle agglomeration
Population balance equation
Shear flow
Impellers
Mixing
Particle size
Shear deformation
Sodium chloride
Tanks (containers)
Bimodal particle size distribution
Experimental conditions
Individual particles
Orthokinetic agglomeration
Particle agglomerations
Polystyrene particle
Rushton turbines
Agglomeration
SDGs
Type
journal article