Dynamics of white water networks during web breaks

A model representing a white water network has been developed to characterize its dynamic behavior. This study focuses on key process modeling issues : the process flow sheet, steady-state mass and energy balances, and a dynamic model and its control system. The system was disturbed by web breaks in the paper machine. During simulations, the manipulated variable used to manage broke inventories was the broke reuse rate. The results emphasize the importance of the process and control design in reducing the impact of perturbations. Application : dynamics modeling is a process-design tool for characterizing the transient behavior and selecting the best control structure to reject disturbances. In existing mills, this tool can be used to develop policies dealing with perturbations to improve performance, to save energy, and to minimize the impact on the environment.