Long-term Hot Corrosion Behavior of Boiler Tube Alloys in Waste-to-Energy Plants
- 234 Downloads
Accelerated corrosion of candidate alloys was induced by metal chlorides/sulfates at 500 °C. Results suggest that the corrosivity of the studied metal chlorides increases in the order CaCl2 < NaCl < KCl < ZnCl2 < PbCl2 < FeCl2. Mechanisms to explain the different impacts of chlorides were proposed. It is believed that materials exposed to chloride salts corrode through vicious cycles, in which a shorter path of the cycle leads to a higher corrosion rate. Experimental results confirmed that FeCl2 with the shortest path of the corresponding vicious cycle has the highest corrosion rate. It is also confirmed that the sulfates of Zn and Pb are less corrosive than their chlorides for the alloys tested. A kinetic study on the hot corrosion of T22, Esshete 1250 and Sanicro 28 was carried out under simulated waste-to-energy (WTE) ashes at 500 °C for 1000 h. Results from the kinetic study show that T22, Esshete 1250, and Sanicro 28 exhibited comparable performance for short-term exposure; however, the degradation thickness presented a clear trend after the 1000-h exposures in terms of decreasing resistance to corrosion: T22 > Esshete 1250 > Sanicro 28. EDX maps confirmed the role of Ni/Cr for slowing the corrosion kinetics of these three alloys.
KeywordsWTE Hot corrosion Candidate alloys Chlorides Sulfates
The authors gratefully acknowledge the financial support of the Natural Sciences and Engineering Research Council of Canada and Nexterra Systems Corporation.
- 5.D. Mudgal, S. Singh, S. Prakash, International Journal of Corrosion (2014).Google Scholar
- 12.H. Krause, Historical perspective of fireside corrosion problems in refuse-fired boilers, Paper No. 93200, Corrosion/93, NACE International, (1993).Google Scholar
- 13.P. Henderson, P. Ljung, P. Kallner, J. Tollin, Fireside corrosion of superheater materials in a wood-fired circulating fluidised bed boiler, EUROCORR 2000 conference, September 10-14, 2000, London, published Institute of Materials, Minerals and Mining, London, 2000.Google Scholar
- 19.D. Bankiewicz, Corrosion behaviour of boiler tube materials during combustion of fuels containing Zn and Pb, Academic Dissertation, Åbo Akademi, Faculty of Chemical Engineering, Process Chemistry Centre, Åbo (2012).Google Scholar
- 20.M. Norell, P. Andersson, Field test of waterwall corrosion in a CFB waste boiler, Paper No. 00236, Corrosion 2000, NACE International (2000).Google Scholar
- 22.M. Born, VGB Powertech 85, 107 (2005).Google Scholar
- 27.H. Pickering, F. Beck and M. Fontana, Materials Transactions ASM 53, 793 (1961).Google Scholar
- 33.I.G. Wright, H.H. Krause, Assessment of factors affecting boiler tube lifetime in waste-fired steam generators: new opportunities for research and technology development, Report No. NREL/TP–430-21480. National Renewable Energy Lab., Golden, CO (United States) (1996).Google Scholar
- 34.H. Krause, Corrosion by chlorine in waste-fueled boilers, R.W. Bryers (Ed.), Proceedings of the Incinerating Municipal and Industrial Waste—Fireside Problems and Prospect for Improvement Conference, Sheraton Palm Coast, , Hemisphere Press (1989), p. 145.Google Scholar