Modeling, Operation and Optimization of Experimental Seeded Batch Crystallization of Adipic Acid
Date Issued
2016
Date
2016
Author(s)
Cho, Hung-Chih
Abstract
Crystallization is a commonly used process for the production of pure substances or separating phases. Therefore, it is important to understand the characteristics of the crystallization process through kinetic considerations. General target of this thesis is the experimental examination of the batch-wise crystallization process of adipic acid in water and the determination of relevant kinetic parameters. In this work, a seeded batch crystallization experiment was developed to go through several operation policies. The experiment data at different experimental conditions were collected and were used to determine the kinetic parameters of crystal growth rate and crystal nucleation rate. Then the experiment was made use of investigate the effect of cooling trajectory and seed properties on the product crystal quality and crystal size distribution. In results, compare to the effect on the crystal size distribution between different seed loading and different temperature trajectories, to change the seed loading ratio is a more effective way to suppress nucleation and obtain better product equality. For a given seed loading, linear trajectory perform significantly worse than convex trajectories such as cubic, quartic, and Mullin-Nvylt trajectories. The performance of optimal trajectory is the best. Finally the experiment was used to test the phenomena proposed, which are called ‘early growth’ trajectories and ‘late growth’ trajectories. The ‘early growth’ trajectories give the larger supersaturation in the beginning of the batch than the end of the batch, which will produce a larger number of nuclei but a smaller nucleation mass. In contrast, ‘late growth’ trajectories give the smaller supersaturation in the beginning of the batch than the end of the batch, and it will produce a larger number of nuclei but a smaller nucleation mass. The results confirmed the theoretical prediction to be consistent again.
Subjects
Batch crystallization
seed loading ratio
temperature trajectory
kinetic parameter
early growth
late growth
Type
thesis
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