Numerical reduction of a crystallizer model with internal and external coordinates by proper orthogonal decomposition

Crystallization processes are characterized by close interaction between particle formation and fluid flow. A detailed physical description of these processes leads to complicated high-order models whose numerical solution is challenging and computationally expensive. For advanced process control and other model based real-time applications, reduced order models are required. In this work, a reduced model for a urea crystallizer is derived from a detailed reference model with two external and one internal coordinate. Proper orthogonal decomposition is applied to all three coordinates to obtain a low-order representation of the system. Nonlinear terms are treated efficiently by best points interpolation. Simulations are carried out to show the good agreement between reduced model and reference model.

► We model a urea crystallizer for process control purposes.
► A reference crystallizer model has internal and external coordinates.
► An operator-splitting method is used to solve a coupled population balance system.
► The proposed reduction method is based on empirical basis functions.
► The reduced model shows good agreement with the reference one.