Dimensionless Framework for Seed Recipe Design and Optimal Control of Batch Crystallization
Journal
Industrial and Engineering Chemistry Research
Journal Volume
60
Journal Issue
7
Pages
3013-3026
Date Issued
2021
Author(s)
Abstract
In order to study and propose guidelines for the design and control of batch crystallization systems with different growth and nucleation parameters, optimal control theory and a dimensionless batch crystallization model are applied to solve multi-objective optimization problems in a nearly analytical and computationally efficient way. Optimal growth rate trajectories and the corresponding critical seed recipes (seed loading ratio and seed mean size that make nucleated mass negligible) representing a suitable trade-off between two objective functions (number of nuclei and nucleated mass) are derived for 32 chemical systems. The results are also compared with results from applying supersaturation control, a strategy that can be implemented without a kinetic model. The analysis suggests that the benefit from applying an optimal growth rate trajectory is significant only when the sensitivity of nucleation rate to supersaturation is significantly greater than that of the growth rate. Furthermore, the width of the crystal size distribution has little effect on the critical seed recipe. The effect of the batch time on the critical seed loading ratio is also studied for individual systems. It is found that increasing batch time helps to reduce the seed loading requirement for systems in which the nucleation rate is highly sensitive to supersaturation. ?
Subjects
Crystallization; Economic and social effects; Growth rate; Multiobjective optimization; Nucleation; Supersaturation; Batch crystallization; Computationally efficient; Crystal size distributions; Multi-objective optimization problem; Nucleation parameters; Objective functions; Optimal control theory; Supersaturation controls; Loading
SDGs
Type
journal article