Designing and modifying HRSGs for cycling operation Designing and operating HRSGs for cycling duty requires close cooperation between the manufacturer and the user. Once HRSGs are in service, a monitoring system should provide a thorough picture of the mechanisms affecting the life and integrity of the boiler

Today's heat-recovery steam generators (HRSGs), a vital component in the popular combined-cycle plant, are exposed to more severe duty than merely running at baseload. Unless properly designed and operated to withstand this cycling duty, the integrity of the HRSG will be compromised. For new projects, damage control begins with the specification of certain design features. Operation and maintenance practices also play an essential role in managing HRSG life, both for new and existing plants. Existing plants also should explore modifications and monitoring programs that can boost the reliability and extend the service life of HRSGs in cycling duty. HRSG design features, modifications to equipment, and adjustments in operating practices are presented.