Thanks to all who attended the June 2009 EPRI Condensate Polishing Workshop/Condensate Filter Users Group meetings in New Orleans and the June/July EPRI-sponsored Combined Cycle Workshop in Boston. Because many were unable to attend due to budget restrictions in these tough economic times, this edition of PowerLine® summarizes key presentations from these events. Please contact www.EPRI.com for copies of the full presentations that are not available through links below.
Graver Technologies' Charlie Mosser, a world-renowned expert in condensate polishing, discussed in the Condensate Filter Users Group Meeting how the original inventors of the Powdex® process anticipated 90% efficiency in both corrosion and ionic contaminant removal from condensate. However, with subsequent advances in septa design, attachment hardware, powdered ion exchange products and precoat techniques, today's plants experience >99% efficiency in the parts per trillion (PPT) range!
Click here to view Mosser's presentation.
Graver Technologies' full-flow guide-rod assembly and SealFast® technology provide reliable filter to hardware connection.
Al Tavares of Graver Technologies presented a companion paper to Charlie Mosser's presentation at the BWR Users Group Meeting, in which he detailed improvements to polishing powdered precoat products that contribute to today's excellent performance record. Improvements discussed include particle size, resulting kinetics, filtration characteristics and floc formation.
Click here to view Tavares' presentation.
This slide shows two Millipore filter disks: a competing precoat product (L) showed bleed through and the Graver Technologies precoat (R) indicates no iron bleed. A Graver DualGuard® filter precoated with Graver Powdex® is the best option for removing iron and soluble cobalt.
Bryan Hamilton of Tennessee Valley Authority's (TVA) Browns Ferry BWR Nuclear plant and Wayne Norwood of Graver Technologies LLC presented a case study about the Aegis® DualGuard® III condensate polishing septa and advanced hardware systems installation at Browns Ferry. TVA installed the system to address issues with disengagement of septa from attachment hardware that resulted in reactor water chemistry excursions and increased septa replacement and maintenance costs. Since retrofit and installation of the first DualGuard III septa beginning in 2006, the plant has eliminated resin leakage and resulting sulfate excursions, and has enjoyed trouble free operation for nearly three years. The paper discusses operational difficulties that prompted TVA's decision to modify their CP units as well as the upgrade strategies and resulting chemistry and operational results.
Browns Ferry reactor water sulfate concentrations, once the highest or near the highest among BWRs with CF/Ds, are now below the median value for these plants.
Dr. Peter Yarnell of Graver Technologies and Michael Lunny of Dominion Nuclear CT discussed the history of the Gravex® ultra low chloride anion resin and amine form cation resin at Dominion's Millstone Nuclear Power Station. Lunny described the successful conversion of all beds in the Unit 2 condensate polishers to the amine form as well as the issues and benefits (cost savings) of those conversions. He also highlighted the successful resolution of the seawater ingress to the corresponding beds in Unit 3 in late 2008.
Dr. Yarnell discussed the successful installation of the ultra low chloride anion resin beds at the Millstone plant. The oldest bed in service has treated >7 billion gallons of condensate with current effluent chloride of only 2 ppt. The ultra low chloride anion resin raised levels of ethanolamine that, in turn, dramatically lowered iron transport. Dr. Yarnell also described development work on ultra low sulfate cation resins through extended post-treatment and Graver's ongoing search for a beta site(s) to evaluate the most promising candidate from this study.
Click here to contact Graver about becoming a beta site.
TOC reduction from rinsing the standard gel strongly acidic cation.
Change in extractable sulfate levels from gel strongly acidic cation as received from the manufacturer, after standard Graver plant rinse and after extended post-treatment.
The EPRI-sponsored Combined Cycle Workshop in Boston, Massachusetts from June 30 through July 2 highlighted Graver's technology. Mark Koster presented a paper titled Condensate Polishing and Filtration Applications in China - A Supplier's Perspective; other presentations highlighted developments in condensate polishing technology and performance improvements through Graver Technologies.
A paper was presented that discussed the long term protection of electric power generating station boilers, which depends upon the quality of their feed water chemistry with respect to the transport and deposition of corrosion products to the boilers from various corrosion sources in the plant's condensate and feed water cycle. The Large Diameter High Flow (LDHF) condensate filter systems are finding increased use in fossiland nuclear applications. Graver's TurboGuardTM LDHF filter has been designed to reduce the transport of corrosion products. This technology is particularly useful in combined cycle plants that experience high CRUD loadings during start up.
Click here to view TurboGuardTM product information.
TurboGuardTM Filters are available in any length or micron rating to meet every application need.
Ian Richardson, an environmental and industrial chemist, presented a success story about an air-cooled coal-fired power plant in Australia with severe ACC corrosion and corrosion product transport within the water steam cycle. Cycle chemistry changes reduced corrosion within the ACC, but corrosion product removal from the condensate was insufficient due to an underperforming condensate filtration system. Graver Technologies AFA2005 media septa replaced the existing wound polypropylene elements, resulting in less than 1 ug/L of iron in the filtered condensate as well as dramatically reducing transport of corrosion products into the boiler and iron fouling of polisher resins. In addition, cleaning time, backwash frequency, backwash water usage and filter downtime have decreased by 90 percent with concurrent increase in condensate polisher resin life.
Click here to view Graver Technologies' AFA page.
Click to view the technical bulletin for more information about this presentation.
AFA 2005 filters are available in a variety of end configurations to suit specific applications in any condensate system.