Optimal Start-Up Strategies for Continuous Crystallization Process with COBC Crystallizer

A model-based optimization procedure was developed to systematically investigate different start-up strategies of continuous crystallization process using continuous oscillatory baffled crystallizer (COBC). An optimal steady state of the crystallization process was firstly designed to setup the optimal steady state operating conditions and the end-point for the start-up process. Then a multi-objective optimization problem was formulated to find the optimal strategy of the start-up process which minimizes the start-up time and the material waste. The decision variables of the optimization are input flow rate, jacket cooling temperature, the concentration of the pre-filled solution in the crystallizer. Different scenarios with single and multiple decision variables were designed and compared. It was shown that the start-up time can be reduced by more than 45% when all the decision variables are optimally set.