Summary
The heat recovery steam generator sits between the combustion turbine and the steam turbine in a combined cycle plant, capturing exhaust heat and converting it into steam — and inheriting operating requirements from both machines in the process. That position subjects the HRSG to severe thermal transients, a wide range of loads, and high steam temperatures and pressures, which together open the door to an unusually broad set of damage mechanisms. Many units were designed for base-load service and are now cycled daily, while modern designs push steam temperatures beyond 1,100°F on advanced alloys that introduce challenges of their own. Structural Integrity Associates (SIA) has spent decades helping power generation owners manage the full life cycle of these assets.
SIA engineers begin where the risk is defined. Header and tubing assessments audit HRSG design and operation to determine which damage mechanisms are active, estimate likely remaining life, and recommend inspection methods and intervals — or the operational and design changes that slow the damage down. Cycle chemistry and flow-accelerated corrosion audits surface water-steam-side concerns that extend beyond the HRSG into the condenser and steam turbine. Inspection planning then turns those findings into a scope that reduces frequency on lower-risk components and concentrates effort where it will extend asset life.
When it is time to look inside the unit, SIA’s NDE professionals inspect HRSG tubing, piping, and headers using methods matched to the mechanism: oxide scale and component thickness measurements, linear phased array and TOFD weld examinations, and specialized techniques for hydrogen damage and corrosion fatigue. Creep strength enhanced ferritic steels warrant particular attention, and SIA is an industry leader in Grade 91 and Grade 92 across design, fabrication, operation, analysis, and inspection. If a component fails, our Metallurgical Laboratory performs metallurgical testing and root cause analysis to identify causative factors and prevent the failure from recurring.
Attemperators earn a review of their own. SIA evaluates attemperator design, operation, maintenance, and control logic to identify deficiencies and advise on mitigations ranging from revised control logic to physical design upgrades — work supported by the finite element and creep-fatigue analysis capability within our advanced engineering practice. Online attemperator monitoring is available through PlantTrack, SIA’s asset integrity data platform, whose online modules form part of the SIIQ™ real-time damage tracking suite. Together these services give HRSG and boiler owners a defensible basis for inspection scope, repair timing, and capital planning. Contact SIA to discuss your unit.