Crystallizer design is often hindered by the lack of scaleup rules, hydrodynamic information, and predictive crystallization modeling tools. A hybrid CFD compartmentalization batch cooling crystallizer model is proposed to take into account localized mixing, heat transfer, and fluid hydrodynamics, combined with key process engineering information obtained on a laboratory scale. The compartments were identified using CFD simulations based on the crystallizer geometry and operating conditions. The population, mass, concentration, and energy balance of each compartment is modeled separately as a well-mixed MSMPR unit with input and output streams. The software gPROMS ( Process Systems Enterprise Limited) is a process-modeling tool that can facilitate compartmental modeling and will be used for the prediction of the crystallization behavior upon scaleup.