CRYSTALLIZATION CALORIMETRY FOR THE ASSESSMENT OF BATCH SEEDING AND COOLING POLICIES

Some applications of on-line calorimetry to vacuum-cooled batch crystallizers are reported. Pilot-scale batch operations are analysed. It is shown that real-time estimates of the differential heat of crystallization allow many interesting extensions of diagnostic and control possibilities for seeded and unseeded crystallizers. For unseeded crystallizations, it appears that the calorimetric approach provides quantitative results on primary nucleation. In an industrial context, these results could be used for the early diagnosis of the product quality. For seeded operations, information is obtained on the effect of seeding and cooling parameters. Such information is found to be of great interest for the design of improved operating conditions including the seeding temperature, the amount of seeds or the cooling rates for example.