Greg Epelbaum, Boiler Engineering ... - Home - …

1 Greg Epelbaum, Boiler Engineering Manager, Covanta EnergyEric Hanson, Boiler Reliability Director, Covanta EnergyDr. Michael Seitz, President AmStar Surface TechnologyMay 12, 2010, Orlando, Florida, USA Fireside corrosion is the biggest challenge for EfW boilers MSW is the most heterogeneous, unpredictable fuel, which constantly changes with weather, seasons, locations, economy, politics, social behavior, Fireside corrosion is typically driven by the following 4 simultaneously occurring mechanisms: corrosion by gaseous phase including active oxidation by Challenges for EfW Boiler Reliability corrosion by gaseous phase including active oxidation by chlorine (HCl, Cl2) ; condensation of alkali and heavy metals chloride and/or sulfates; deposit induced corrosion and sulfidation of condensed chlorides ; molten salts eutectics cause dissolution of protective oxide scales and tube metal Intensity of corrosion can be controlled to a certain degree by a proper design for an EfW Boiler : combustion system and furnace design.

2 Proper design criteria for the main operating parameters; smart superheater location Boiler tube surface protection: refractory;Solutions to improve EfW Boiler Reliability refractory; tube shields; surface treatments, such as weld overlays, thermal sprays, laser claddings and fused coatings, and AmStar 888 is one of these technologies, and like some others, it can be use as a part of the solution; Relevance and importance to EfW future The material development of Alloy 888 was initiated in 2002, in a partnership between special Metals Welding Products company and AmStar Surface Technology. This material (which is a Nickel Chrome alloy, with carbide and boride additions) was developed for environments with erosion, corrosion, or a combination of both. It became a proven technology for many large utility boilers, Fluid Bed boilers, recovery boilers, refineries before it entrance to EfW. The coating is applied using a high velocity spray system AMSTAR 888 CLADDING MATERIAL The coating is applied using a high velocity spray system (HVCC), and requires no post treatment: can be field or shop applied ; can be applied over untreated surface or potentially over treated surface, such as inconel weld overlay; can be repaired if defects occur in the future AmStar 888 cladding technology is a combination of the new alloy and the special coating technique.

3 AmStar Surface Technology company is developer and applicator. AmStar 888 cladding technology was proven in other industries, but not in EfW. To find cost effective alternatives to inconel Weld overlay. To expand boundaries of Boiler tube protection by surface treatments:AMSTAR 888 CLADDING TRIALS AT COVANTA PLANTSO bjectives treatments: different facilities; different Boiler designs; different Boiler areasMontgomery Boiler , MSW 600 TPD: 885psi, 830F, 171 KPPHAmStar Pass2 RW application at MontgomeryFlue Gas T: 1300 1600 F; Tube metal t: ~550 FPass2 RW ~130 ft2 area prepared by AmStar prior to cladding B#3 Jan-08 Outage Coating thickness reading before applying PassivatorAmStar Roof WW application at MontgomeryFlue Gas T: 1000 1200 F; Tube metal t: ~550 FRoof WW area covered by slag before it was removed prior to AmStar s cladding B#3 Jan-08 Outage Roof (Screen-FSH) ~130 ft2 After applying PassivatorAmStar Pass2 RW application at MontgomeryBoiler 3 - March 2010 OutageAmstar Coating - 2nd Pass RWTOP7' DOWNTube #thicknessthicknessLeft #3 Mar-10 Outage Pass2 RW inspection: No Coating loss, Passivator s intactB#3 Mar-2010 Outage Pass2 RW Tube Trial at Montgomery B#2 FSHFlue Gas T: 1000 1200 F; Tube metal t: ~750 - 800FB#2 Sep-09 Outage AmStar Tube sample (third from Left) after ~ 6months operation York Boiler , MSW 448 TPD: 800psi, 800F, 138 KPPHAmStar Furnace RW application at York B#2 Flue Gas T: 1500 1800 F.

4 Tube metal t: ~530FB#2 Pass1 RW ~200 ft2 area with some refractory obstruction prior to cladding12 months later: no thinning ordelamination in the area ofcladding applied over old WOAmStar Tube Trial at York B#1 Finishing SHAmStar 888 cladding on left tube after years of operation in comparison to an unprotected adjacent tube being in service for only 18 Flue Gas T: 1200 1500 F; Tube metal t: ~730 - 770 Fbeing in service for only 18 months;Mar-2010 Outage:Same condition after ~5 years of operationNiagara Boiler , MSW 1100 TPD: 1275psi, 750F, 305 KPPHAmStar Tube Trial at Niagara B#4 Finishing (SH3)Flue Gas T: 1200 1300 F; Tube metal t: ~750 - 790 FMar-2010 Outage:Trial tube removed during SH3 replacement after ~1 year of operationEssex Boiler , MSW 760 TPD: 650psi, 760F, 240 KPPHM etal Protection Trial in Essex Platen SHInstalled in Essex #1 Mar-08 Panel 3-4 Top 40ft: Ams888 Panel 3-5 Top 40ft: Cladding Y Panel 3-6 Top 40ft: Cladding XFlue Gas T: 1400 1600 F; Tube metal t: ~750 - 820 FAmStar Platen Finishing SH application at Essex B#1 After 1 year of operationAmStar Panel 3-4 (left) and Coating Y Panel 3-5 (right)Panel 3-7 (non-trial) with inconel 625 weld overlay for the lead and trail tubes and 8 unprotected SA-213T22 tubes in betweenAmStar Platen Finishing SH application at Essex B#1 After 2 years of operationAmStar Panel 3-4 at 10' from Roof (lead tube at the front).

5 AmStar Panel 3-4 at 35 from Roof welded to non-trial panel with inconel 625 weld overlay for the lead and trail tubes and 8 unprotected SA-213T22 tubesConclusion AmStar 888 cladding technology has been tested in a number of field trials over the last 4 years at different EfW facilities. It has shown very encouraging results, with no thickness loss (wastage) for Waterwalls (including those covered by old and deteriorated weld overlays). It has also shown very promising results for some superheater applications, where the metal temperatures do not exceed a level conservatively estimated to be approximately 800 F (425C). (425C). However, at the Essex FSH trial AmStar 888 cladding, as well as other surface treatments, have not achieved the desired performance for certain SH tubes: more investigation and field trials should and will be conducted; especially with a trend in EfW calling for higher plant efficiencyHigher SH Steam P & T would result in more challenging superheater location Many thanks to the plants for their support for these field trials