Design on the Installation Position of Thermal Stress Monitoring System for CFBC Boiler of Thermal Power Plant

The purpose of this study is to determine the installation position of thermal stress monitoring system through the lifetime calculation for fatigue and creep damage in CFBC (Circulating Fluidized Bed Coal) boiler with operating temperature of above 427°C. For it, the stress levels of the major pressure components in CFBC boiler were evaluated by Finite Element Analysis (FEA). With the results, the safety assessment based on the cumulative damage analysis was carried out in accordance with ASME NH code. According to FEA results, the maximum combined cumulative damages of 0.85 under the design loading conditions were found in the superheater outlet. However, total damages of the superheater outlet were below the critical value (1.0) specified by the creep-fatigue damage envelope of Cr-Mo material specified in ASME-NH code. From the results, the installation position of thermal stress monitoring system was determined as the superheater outlet for real time process calculations and securing structural safety of CFBC boiler.