Dynamic simulation of a solar power plant steam generation system

An innovative steam generation system for a solar power plant has been designed in Germany by Balcke-Duerr. In order to assist its construction, a dynamic simulation of the thermal oil heated boiler has been developed by the Vienna University of Technology. Aim of this work is to assess how critical is the boiler behavior for the plant operation during a start-up phase, and especially to check if the natural water circulation starts correctly. After a description of the heat exchanger design, the different stages of the simulation build-up with the software APROS are described. As a result of the model validation, the improvement of the model discretization is outlined along with the calibration of the heat transfer coefficients. Further on, the observation of relevant parameters of the system (water circulation rate, steam mass fraction and critical heat flux) during the simulated start-up, allow characterizing the boiler. Thus, the natural circulation start can be described with a good fidelity. Findings about the economizer behavior and the occurrence of boiling crisis are also exposed. Eventually, a design optimization can be carried out through the applied method.