DEVELOPMENT OF A NOVEL WWDJ-BATCH CRYSTALLIZER SUITABLE FOR PRODUCTION OF LARGE CRYSTALS WITH A NARROW CRYSTAL SIZE DISTRIBUTION AND CONTROL OF CRYSTAL POLYMORPHS

摘要

A novel batch crystallizer named the WWDJ batch crystallizer was developed. It is equipped with a Wall Wetter{sup}(RTM) and a double-decked jacket. The Wall Wetter is a specially designed slurry sprinkler. The Wall Wetter raises slurry from the crystallization volume covered with the lower jacket of a low temperature to the inner wall of the headspace covered with the upper jacket of a high temperature. Fine crystals are preferentially dissolved during the fall along the inner wall of a high temperature. The expense of super-saturation thus produced is used for growing large crystals. By recycling the slurry between the crystallization volume and the upper wall, large crystals with a narrow size distribution can be obtained. On the other hand, control of crystal polymorphs is also important in the manufacturing of pharmaceuticals. The WWDJ batch crystallizer is used for selective production of a target crystal polymorph by controlling temperatures of the upper and lower jacket. Furthermore we also incorporated a filtration system into the WWDJ-batch crystallizer. By using the filtration system, we can separate crystals from the remaining solution without taking out crystals outside from the crystallizer. The WWDJ batch crystallizer is suitable for crystallization of pharmaceuticals, because it is easy to wash.