DOI QR코드

DOI QR Code

Experimental Simulation of Iron Oxide Formation on Low Alloy Steel Evaporator Tubes for Power Plant in the Presence of Iron Ions

  • Choi, Mi-Hwa (Environment and Chemistry Team, Korean Electric Power Research Institute) ;
  • Rhee, Choong-Kyun (Department of Chemistry and Graduate School of Analytical Science and Technology, Chungnam National University)
  • Published : 2009.11.20

Abstract

Presented are the formation of iron oxide layers on evaporator tubes in an actual fossil power plant operated under all volatile treatment (AVT) condition and an experimental simulation of iron oxide formation in the presence of ferrous and ferric ions. After actual operations for 12781 and 36326 hr in the power plant, two iron oxide layers of magnetite on the evaporator tubes were found: a continuous inner layer and a porous outer layer. The experimental simulation (i.e., artificial corrosion in the presence of ferrous and ferric ions at 100 ppm level for 100 hr) reveals that ferrous ions turn the continuous inner oxide layer on tube metal to cracks and pores, while ferric ions facilitate the production of porous outer oxide layer consisting of large crystallites. Based on a comparison of the oxide layers produced in the experimental simulation with those observed on the actually used tubes, we propose possible routes for oxid layer formation schematically. In addition, the limits of the proposed corrosion routes are discussed in detail.

Keywords

References

  1. Iwata, O.; Kobayashi, N.; Misaka, Y.; Mori, T.; Okasaki, M.; Sanda, K.; Suzuki, T.; Tanaka, C.; Watanabe, T. Kurita Handbook of Water Treatment; Kurita Water Industries Ltd.: Tokyo, 1985; p 357
  2. Mann, E. C.; Potter, G. M. W. 1st Int. Congress on Metallic Corrosion 1961, 8, 417
  3. Heitmann, H. G. Handbook of Power Plant Chemistry; CRC Press, Inc.: New York, Boca Raton, Florida, U. S. A., 1993; p 376-379
  4. Ranjbar, K. Engineering Failure Analysis 2007, 14, 620
  5. Matsubara, M.; Itaba, S.; Miyajima, M. Powerplant Chemistry 2006, 8, 203
  6. Bornak, W. E. Corrosion 1988, 44, 154 https://doi.org/10.5006/1.3583918
  7. Pieper, B. VGB Kraftwerkstechnik 1996, 76, 383
  8. Jain, P.; Bhakta, U. C. Powerplant Chemistry 2007, 9, 746
  9. Ghanem, W. A.; Bayyoumi, F. M.; Ateya, B. G. Corrosion Science 1996, 38, 1171 https://doi.org/10.1016/0010-938X(96)00012-1
  10. Elisabeth, M. F.; Holmes, D. R. Corrosion Science 1965, 5, 362
  11. Dooley, R. B.; McNaughton, W. P. Boiler and Heat Recovery Steam Generator Tube Failures: Theory and Practices Vol. 1; Electric Power Research Institute: California, 2007; p 6-5, p 13-3
  12. Bartholomew, R.; Cline, D.; Hull, E.; Shields, K.; Siegmund, J.; Yorgiadis, S. Guidelines for Chemical Cleaning of Conventional Fossil Plant Equipment; Electric Power Research Institute: California, 2001; p 1-11
  13. Dooley, R. B.; Ball, M.; Bursik, A.; Jonas, O.; Pocock, E. J.; Rice, J. K. Selection and Optimization of Boiler Water and Feedwater Treatments for Fossil Plants; Electric Power Research Institute: California, 1997; p 3-5
  14. Dooley, R. B. Cycling, Startsup, Shutdown, and Layup Fossil Plant Cycle Chemistry Guidelines for Operators and Chemists; Electric Power Research Institute: California, 1998; p 6-4, 6-6
  15. Dooley, R. B. Cycle Chemistry Guidelines for Fossil Plants: Oxygenated Treatment; Electric Power Research Institute: California, 2005; p 2-
  16. Robert, D. P.; Harvey, M. H. The Nalco Guide to Boiler Failure Analysis; MacGraw-Hill, Inc.: New York, 1991; p 81-82
  17. Dooley, R. B.; Chexal, V. K. International Journal of Pressure Vessels and Piping 2000, 77, 87