方解石的聚合物絮凝：群体平衡模型

A population balance (PB) model is used to describe the aggregation/breakage kinetics
of calcite flocculation in turbulent pipe flow. The model describes simultaneous aggregation
and breakage, and accounts for likely process variables: fluid shear, flocculant
dosage, primary particle size and solid fraction, using four fitted parameters. Particle
collision is described by the turbulent collision kernel of Saffman and Turner,1 however,
the capture efficiency ( ) is initially set to equal zero until the point of flocculant addition,
then increases rapidly as described by an equation accounting for flocculant mixing/
adsorption. Particles aggregated by high-molecular weight polymer flocculant typically
do not achieve a steady-state aggregate size, where the rates of aggregation and breakage
are equal. Instead, the aggregate size decreases gradually due to polymer chain scission
or rearrangement on repeated aggregation/breakage. This phenomenon is accounted for
in the model by a flocculant strength degradation term. © 2006 American Institute of
Chemical Engineers AIChE J, 52: 1641-1653, 2006