Simulation, parameter estimation and optimization of an industrial-scale evaporation system

Abstract

Design and operation of complex industrial systems can be improved based on simulation and optimization using physical process models. However, this endeavor is particularly challenging for hybrid systems, where in addition to the continuous evolution described by differential algebraic equations the dynamic process shows instantaneous switches between different operating modes. In this study, we consider parameter estimation for an industrial evaporation system with discrete mode switches due to phase transitions. Simulation results of the hybrid evaporator model are compared with those of a smooth evaporator model. A smoothing approach is applied in order to modify the hybrid model such that the discrete transitions are integrated into the system of differential algebraic equations. This leads to exclusively smooth trajectories, making the model suitable for parameter estimation to be solved by means of gradient-based optimization methods. The dependence of the parameter estimation results on the smoothing parameter is investigated.