Optimal operation of nanofilter based diafiltration processes using experimental permeation models

In this paper, a choice of models for optimal control strategy is discussed for batch membrane processes. The system of lactose and salt in water is studied with the separation aim being concentration of lactose and simultaneous removal of salt. The most crucial part of the model is dependence of permeation rate on concentrations of components. Two models from literature and one data-based model are fitted to experimental data. An optimal control problem (OCP) is formulated to minimize processing time using diluant-to-permeate flow ratio as the control input. The optimal control strategy is found analytically and verified using numerical methods of dynamic optimization. The resulting processing times and the optimal input profiles are compared between all the models. Simulation case study confirms the attractiveness of the proposed approach.