High shear breakage of compact polyelectrolyte-bridged flocs: A method for obtaining model-independent breakage rate function data

Abstract

A method of obtaining model-independent breakage rate or fragmentation kinetic function (FKF) data in the population balance (PB) equation (PBE) was proposed for the high shear breakage of compact polyelectrolyte-bridged alumina flocs. The continuous particle size distribution function (PSDF) data were obtained as a function of fragmentation time. The PSDF data at zero fragmentation time was and must be used as the input in the PB modelling. Computed temporal PSDF curves were obtained by solving the dimensionless log-form PBE using a FKF based only on the fragmenting particle and a daughter size. Another important requirement is that the experimental time must be used in the scaling. Using appropriate values for the parameters in the FKF, an excellent match between the temporal experimental and computed PSDF data was achieved. Upon meeting all these conditions, the FKF values used in the computation should truly represent the experimental values for all father-daughter size combinations encountered in the fragmentation process. The fragmentation occurred in the rotor-stator device under the conditions where the Kolmogorov microscale and characteristics velocity gradient of 37 μm and 1600 s−1. The ratio of the largest to smallest length scale turbulent eddies was 2047.