Metastable Limit Dynamics and Optimal Cooling Curve of Batch Seeded Crystallization
| Authors: | Lee Kwang Soon, Sogang University, Korea, Republic of
Won Seunghee, Sogang University, Korea, Republic of
Choi Chung S., Sogang University, Korea, Republic of
Lee Ju-Seok, Korea University, Korea, Republic of
Yang Daeryook, Korea University, Korea, Republic of |
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| Topic: | 6.1 Chemical Process Control |
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| Session: | Process Control Applications |
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| Keywords: | Batch Crystallization, Cooling Crystallization, Metastable Limit, Batch Model Predictive Control |
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Abstract
For seeded cooling crystallization, the supersaturation is required to be maintained at a level within the metastable limit in order to suppress the homogeneous nucleation. However, the metastable limit is not fixed but time-varying depending upon the solution history. In this study, dynamics of the metastable limit has been exploited. Using the experimental results obtained under various cooling rates, the metastable limit was expressed to have a nonlinear first-order dynamics to a change in the cooling rate. By incorporating this model, an optimal cooling curve was determined for (NH4)2SO4 Crystallization from the (NH4)2SO4-NH4NO3-H2O ternary system and experimental verification has been performed.
