Figure captions
Figure 1. Principle of MACC and comparison with classic cooling crystallizations. (a) Schematic diagram of the ideal MACC process; (b) Micro force field model of surface induced nucleation and self-seeding process (c) Comparison of the different force acting on the crystal with different size; (d) Heat transfer model of membrane module in MACC; (e) cooling crystallization with artifical seeding; (f) cooling crystallization with spontaneous nucleation.
Figure 2. SEM for the microstructure of PTFE membrane (a-f) and PES membrane (g-l).
Figure 3. Experimental setup of MACC (left), the temperature route for membrane induced nucleation and growth in crystallizer (right).
Figure 4. On-line observation of crystal growth and self-detachment on the membrane surface.
Figure 5. (a) Measured thermal conductivity and (b) XRD of PTFE and PES membrane.
Figure 6. AFM (2D and3D) images of the surface roughness of the PTFE membrane (a, b) and PES membrane (c, d).
Figure 7. Contact angles of pure water and different thiourea aqueous solution on PTFE and PES hollow fiber membrane.
Figure 8. The nucleation induction period of thiourea in PFTE and PES membrane module with different package density. (membrane module type: (a) PTFE-1, (b) PTFE-2, (c) PTFE-3; (d) PES-1, (e) PES-2, (f) PES-3; number in the figure: package density of corresponding membrane module)
Figure 9. Comparison of solution temperature fluctuation in the crystallizer during nucleation period (PTFE MACC, PES MACC, seed CC with different seed amount and common CC with different cooling rate were listed).
Figure 10. Comparison of crystal size distribution under different MACC and conventional cooling crystallization at different crystallization period. (a) 5 min after the initial nucleation (or seeding); (b)10 min after the initial nucleation (or seeding); (c) terminal products.
Figure 11. On line images of crystal nucleation, growth procedure in 10 L crystallizer and the terminal crystal products of different MACC and conventional cooling crystallization (with seed and no seed).