The client contacted ETD to submit a proposal on Remaining Life Assessment (RLA) for boiler pressure parts by performing on-site inspection, analysis and assessment on tubes, T-piece nozzles, stub tube weldments and hot reheat pipe weldment for final superheater (FSOH) & reheater (ROH). The work involved performing on-site inspections - ultrasonic thickness measurements (UT) of tubes (wall thickness & bore oxide scale), EMAT (Electromagnetic Acoustic Transducer), replication and hardness measurements of selected locations. The inspection data was then used to estimate effective tube metal temperature and identify material degradation which could be used for damage assessment and predicting the remaining life of outlet headers and tubes of the FSOH & ROH.
The objectives and scope of the work to be carried out were:
- Reviewing the drawings of FSOH & ROH, tube banks of the boiler to be studied and identify accessible test locations for on-site inspections;
- Performing on-site ultrasonic thickness (UT) measurements of tube wall thickness and bore oxide scale for FSOH & for ROH tubes;
- Performing on-site EMAT (Electromagnetic Acoustic Transducer) testing of tube wall thickness for FSOH & ROH tubes;
- Performing on-site replication and hardness measurements on straight tubes, T-piece nozzle weldments, stub tube weldments and hot reheat pipe weldment for FSOH & ROH;
- Assessing all replicas by using OM (optical microscope) to confirm the damage condition. Further assessment was also made of selected P/T/F91 & T23 replica(s) by using SEM (Scanning Electron Microscope), if necessary, to confirm the damage condition;
- Assessing the damage and material degradation of FSOH & ROH outlet headers, tubes, T-piece nozzle weldments, stub tube weldments and hot reheat pipe weldments based on the replication and hardness measurements data;
- Reviewing & analysing UT inspection data and estimation of wall thickness loss & tube metal temperature;
- Assessing the remaining life of FSOH & ROH components based on estimated tube metal temperature and other inspection data;
- Reviewing & analysing previous failures, inspection and maintenance data for other pressure parts (i.e. economiser, etc) of the boiler to complete the life assessment study;
- Preparing a full report including results of on-site inspections, analysis results of damage & life assessment study and make recommendations for any further actions to be taken for safe and reliable operation of the boiler.
For more information about of Remaining Life Assessment & Extension services please click here.