Life-Time Management of Process Devices in Industrial Practice

This dissertation examines life-time management of process and energetic devices in industrial practice, mainly in the area of steam power plants. Furthermore, it focuses on frequent damage mechanisms occurring in this area. It summarizes basics of damaging mechanisms occurring in the process industry area, their monitoring, evaluation and prediction. In the area of steam power plants, the main emphasize was placed on cumulative damage mechanisms. Within the dissertation, mechanisms of creep, fatigue, and their combinations were assessed. Major European standards were examined in order to discuss the amount of contained conservatism and their usability. Subsequently, attention was paid to the methods applicable for creep and fatigue combination evaluation. In the next step life-time monitoring and evaluation standard was discussed. The diagnostic software was created which includes creep, fatigue and creep-fatigue combination evaluation according to valid standards. For online life-time evaluation was proposed refined analytical solution for stress and strain calculation. To further extend the life-time management, the dissertation describes oxide scale damaging together with its evaluation and implementation into diagnostic software. The proposed software is extended by the material module which on the basis of defined materials allows easy and effective usage of material characteristics. For the purpose of refining life-time prediction accuracy, experimental device was schematically described. In addition, the device should be also able to verify used equations. Furthermore, the dissertation includes solution to industrially oriented cases. Firstly, a steam generator with damaged pipes was analyzed, afterwards damaged transferring pipeline. Further analyses deal with U-tube heat exchanger and its damaging. The causes of damage were discovered and corrective measures were proposed. The dissertation concludes with the summarization of potential activities for subsequent research in examined area