HRSG FORUM with Bob Anderson

Enjoy a warm breakfast in the exhibit hall before you begin your day!

Conference Chair Bob Anderson opens HRSG FORUM

Like many utilities Duke Energy is anticipating substantial growth of renewable generation that will require more flexible operation of its existing CCGT units. This presentation describes Duke's experiences in preparing its CCGT units to maintain high levels of reliability and availability during and after this market transition.

: We all know that the introduction and development of renewable energy sources already (and will further) cause an increasing rate of change in the generation business as we have known it. This presentation discusses how CMI diversifies its portfolio with specific attention being paid to Concentrated Solar Power (CSP) and Energy Storage (with the help of various battery technologies).

This presentation will include the international status of cycle chemistry on combined cycle/HRSG plants from over 100 plant assessments worldwide. The latest on chemistry guidance will include the use of film-forming substances (FFS) in HRSGs and air-cooled condensers (ACC) from the recent (March 2019) international IAPWS conference.

Enjoy lunch with your peers; visit the exhibits, all across the hall and around the corner in the Florida Ballroom

During the 2017 & 2018 HRSG Forum Jeff Henry updated attendees on the continuously changing knowledge and Code activities associated with CSEF steels - including details on ASME's reduction of the allowable stress for P91 and creation of a new class of P91. Jeff returns to the 2019 HRSG Forum with another update, including the history of CSEFS development and regulation.

Fouled tube bundles in heat recovery steam generators (HRSGs) can penalize overall plant performance. A common practice is to periodically perform a maintenance cleaning, generally when the drop in pressure reaches an “action required” level. A recent cleaning technology being utilized for application in HRSGs and other power generation facilities is pressure wave cleaning. This approach involves inflation and detonation of a bag (or bags) containing a stoichiometric gas mixture whereby the resulting overpressure and pressure wave from the detonation cleans fouled tube bundles. Multiple cleanings have been performed using this relatively recent technology and cleaning effectiveness has been very positive. Results of testing conducted on the pressure wave cleaning approach will be presented and implications discussed for damage potential and future cleanings.

This presentation will consist of two parts. The first concerns overheating HRSG tube failures (HTF) in Reheater circuits. The second describes the sequential appearances of oxide growth on ferritic materials in steam circuits. A specific case study will apply the large OGE data base to the reheater HTF and suggest how exfoliated oxide can lead to overheating.

Determining the health of components that suffer progressive degradation and damage has typically been achieved by performing Non-Destructive Examination (NDE), which can be costly, and success depends on being in the right place at the right time.  Technology now exists to track the health (or aging) of key components such as headers or piping components due to mechanisms such as creep, fatigue, or, in the case of attemperators, water impingement.  Since leaking and overspray of attemperators are a common industry issue, an example will be provided in how on-line monitoring can identify when these events occur so corrective action can be taken and/or further damage evaluation conducted in a timely manner.

As today’s utilities and generators diversify their generation sources, the existing infrastructure needs to adapt – base-load plants are now being asked to load-follow, cycling more than originally designed. Cyclic service places more demands on the generation asset, particularly in how it responds to moisture ingress into the insulation system. While cyclic systems are down, a pipe is dead-headed, or a drain line is only used during startup/shutdown, the metal temperatures are low enough to allow for the presence of liquid water at the exterior surface of the piping and equipment. As surface wet-time increases, so does external corrosion of metal piping and equipment. The insulation system compounds this problem by not only hiding the issue from plain sight, but by exacerbating the corrosion by absorbing water and holding it against the metal surface for longer periods of time.

Gas turbine upgrades have the potential to increase unit output, efficiency and flexibility and hence improve the competitiveness of combined cycle plants. However, the impacts of any proposed GT upgrade on the HRSG and wider balance of plant must be considered to ensure that the new process conditions are acceptable, that any enhanced risks to process safety or component damage are understood and to ensure that the full capabilities and commercial value of the upgrade will not be limited by the water/steam cycle. This presentation by an international energy company that has both an experienced engineering services group and a large operating portfolio gives owners the opportunity to learn what impacts GT upgrades can have on the HRSG, and how to predict and deal with any negative consequences before performance loss, equipment damage or additional, unexpected capital costs are incurred.

Acoustic monitoring has long been a proven technology for on-line detection of steam and water leaks in conventional boilers, recovery boilers and feed water heaters, but for many years was not used in HRSGs due to the high noise levels associated with gas turbine exhaust. This presentation describes how acoustic monitoring is now a proven and effective tool for early detection of pressure part leaks in HRSGs. Case studies are presented in which early leak detection has provided HRSG plant operations with the ability to mitigate the consequential damage and economic consequences of tube leaks. The use of acoustic monitoring to detect leaking valves is also discussed.

This presentation describes the actions taken to preserve CCGT equipment during long-term (multi-year) layup and then return the unit to service. It also describes lessons learned - what worked and what didn’t.

For the last several years EPRI, Competitive Power Resources, and Flexim have been working to develop a reliable automatic HP superheater/reheater drain control system utilizing ultrasonic technology. This system has been recently released for commercial application. This presentation describes the performance of this system after installation in both new construction and retrofitted to existing HRSGs.