2. Theory of MACC
A schematic diagram of the ideal MACC process is shown in Figure 1. The
crystallization solution and the cooling liquid flow along the shell
side and tube side of the membrane module, respectively. When the
coolant feed into the hollow fiber membrane module, it can decrease the
temperature of the crystallization solution to the metastable zone
effectively due to the outstanding heat exchange property of the
membrane module. The operation pressure difference and temperature
difference on the two sides of the membrane are both small, thus, there
is only heat transfer on the membrane surface, and the transmembrane
mass transfer can be ignored. The induced nucleus on the supercooling
membrane surface then migrates from the membrane surface to the bulk
crystallization solution under the proper flow conditions. To describe
this complicated dynamic process, the relevant model should be
introduced.