In order to produce the desired final crystal form and achieve a high-purity yield, most pharmaceutical and fine chemical manufacturing processes include a series of crystallizations. Crystallization, especially batch crystallization, is still often regarded as "more an art than a science", because of nucleation timing differences, production of polymorphic crystal variants, etc. In 2004, the US Food and Drug Administration (FDA) proposed Process Analytical Technology (PAT）which is intended as a framework for innovative pharmaceutical development, manufacturing, and quality assurance. To apply PAT to ensure the quality of the pharmaceutical products produced using crystallization, JGC has been developing a simulator for the crystallization process. The simulator uses a temperature control loop based on information from in-situ and on-line measurements in combination with crystallization models and CFD. This technology could provide: