CRYSTALLIZATION CALORIMETRY FOR THE ASSESSMENT OF BATCH SEEDING AND COOLING POLICIES

Some applications of on-line calorimetry to vacuum-cooled batch crysta llizers are reported. Pilot-scale batch operations are analysed. It is shown that real-time estimates of the differential heat of crystalliz ation allow many interesting extensions of diagnostic and control poss ibilities for seeded and unseeded crystallizers. For unseeded crystall izations, it appears that the calorimetric approach provides quantitat ive results on primary nucleation. In an industrial context, these res ults could be used for the early diagnosis of the product quality. For seeded operations, information is obtained on the effect of seeding a nd cooling parameters. Such information is found to be of great intere st for the design of improved operating conditions including the seedi ng temperature, the amount of seeds or the cooling rates for example.