Inspection is part of routine maintenance for any Heat Recovery Steam Generator (HRSG). Visual inspections are performed at regular intervals in accordance with the requirements of regulatory bodies and insurers. In the US statutory inspections are mandated typically every year although some jurisdictions allow justification for longer intervals. Additional inspections are sometimes performed to establish the baseline condition of the HRSG (often early in life, but not always) or to perform less frequent special inspections to confirm component integrity.
The HRSG Inspection Planning Guide was first published by Tetra Engineering in 2006. The second edition was published a few years later containing some updates on various inspection techniques.
The book aims at guiding the HRSG Engineer to plan and execute effective HRSG inspections and contains the following:
- Reasons for Inspecting HRSGs
- Planning & Preparation
- What to look for - damage and degradation modes:
At Combined Cycle Power Plants the Heat Recovery Steam Generator (HRSG) is an easily-overlooked, but key component, providing steam to the steam turbine and to attached process steam hosts. While base-loaded HRSGs tend to be the most reliable - cycled or two-shifted plants suffering from accelerated damage - the importance of allocating sufficient resources to maintenance of the HRSG is often only realised in hindsight.
As combined cycle gas turbine plants are called upon to play a larger and more flexible role in the generation mix, it’s important to schedule a comprehensive assessment of major components at key intervals to ensure reliable operation.