Evaluation of the Effects of the Operation Strategy of a Steam Power Plant on the Residual Life of its Devices

In the deregulated market scenario wider power generation flexibility with respect to the past is needed; on the other hand, frequent changes of the operating conditions may reduce the life of the most critical components, such as steam heaters or turbine blades. Fatigue failures produced by cyclic thermal and/or mechanical stresses will be considered in this work. The estimation is based on creep and fatigue failure models and is applied at component level. In particular, in this paper the evaluation of the impact of thermo-mechanical fatigue in the superheater pipes of an actual coal power plant will be determined to estimate its residual life. Then, this evaluation at device level will be translated into plant level assessment. Actually, the last aim of the work is developing an on-line real-time procedure suitable to determine how the present operation choices may influence the residual life of the components and of the whole plant and how to manage the plant under design and off-design conditions. These results are helpful in order to optimise the plant operation over time, assess components state, plan its production schedule, and forecast the expected performance degradation.