Modeling and Control of a Paper Dryer Section Using Modelica

The main purpose of this project has been to model one steam heated cylinder, which was taken as part of a drying section, moreover the design and structure of an existing process has been taken in consideration. To develop this work ModelicaTM software has been used. Particular attention has been paid to reproduce the two time constants behavior of the dynamics in the pressure control loop. This behavior has been observed in existing industrial processes. Other dynamics in the system include; fluid dynamics concerning momentum flow, convective heat flow and pressure, heat dynamics concerning heat flow and temperature inside the cylinder shell has been included. The basic control volume, flow and medium models are all inherited from the ``ThermoFlow'' library, which is still under development in this department. The control is done via a PI controller, the lambda tuning method is applied to tune it. The performance of the whole system was improved. The main contribution of his thesis is to link previous works, which concern paper web modeling and others that concern modeling of thermo--hydraulic systems. The project has been done in collaboration with the ABB company