A novel interfacial induced nucleation and accurate self-seeding via
membrane assisted cooling crystallization
Abstract
Accurate cooling crystallization is vitally important in the production
of highly specialized fine chemicals and pharmaceutical engineering,
etc. Herein, a novel hollow fiber membrane-assisted cooling
crystallization (MACC) was developed to achieve precise nucleation and
self-seeding process control. Poly-tetrafluoroethylene (PTFE) and
polyethersulfone (PES) membrane with diverse interfacial induced
nucleation and thermal conduction properties were introduced to
accelerate the nucleation and then transfer the automatically detached
crystal seed into the crystallizer. Polymeric membrane can dominate the
nucleation kinetic and hinder the secondary nucleation, which was
validated from the theoretical model and on-line detective experiments.
The crystal product manufactured by MACC possessed better morphology,
larger mean size (>1.35 mm), higher purity
(>99.5 wt%) and narrower size distribution than the
conventional cooling crystallization. Space-time process decoupling
between nucleation and crystal growth can be realized via auto-screening
uniform nuclei in the membrane modules and controllable growth in the
crystallizer during MACC.