Use of Calorimetry Model and Batch Control Technique for Scale-Up of Unseeded Batch Cooling Crystallization of Poly(hydroxybenzophenone)

Abstract

A scale-LIP method to design and implement a cooling profile for unseeded batch cooling crystallization has been investigated. The reduced ratio between the heat-transfer area and the Volume during scale-up to a large crystallizer causes an increase in the temperature distribution in the reactor, which can trigger unwanted nucleation around the cold spots of the vessel wall. To address this problem, a method is proposed to design a cooling profile for a scaled-LIP crystallizer that can replicate the seed-generation stage of I small crystallizer by effectively suppressing the unwanted nucleation. The use of a batch control technique as method of implementing the cooling profile in a large crystallizer is also proposed. Experiments were conducted with a 100 mL reactor and a 5 L scaled-up reactor for the unseeded crystallization of poly(hydroxybenzophenone) (PHBP) to verify the performance of the proposed method.