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Investigations of the failure in boilers economizer tubes used in power plants

Moakhar, R. S ; Sharif University of Technology | 2013

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  1. Type of Document: Article
  2. DOI: 10.1007/s11665-013-0567-2
  3. Publisher: 2013
  4. Abstract:
  5. In this study, failure of a high pressure economizer tube of a boiler used in gas-Mazut combined cycle power plants was studied. Failure analysis of the tube was accomplished by taking into account visual inspection, thickness measurement, and hardness testing as well as microstructural observations using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and x-ray diffraction (XRD). Optical microscopy images indicate that there is no phase transformation during service, and ferrite-pearlite remained. The results of XRD also revealed Iron sulfate (FeSO4) and Iron hydroxide sulfate (FeOH(SO4)) phases formed on the steel surface. A considerable amount of Sulfur was also detected on the outer surface of the tube by EDS analysis. Dew-point corrosion was found to be the principal reason for the failure of the examined tube while it has been left out-of-service
  6. Keywords:
  7. Dew point ; Economizer tube ; Dew points ; Economizer tubes ; Ferrite-pearlite ; High pressure ; Iron hydroxides ; Micro-structural observations ; Visual inspection ; Boilers ; Combined cycle power plants ; Corrosion ; Economizers ; Energy dispersive spectroscopy ; Failure analysis ; Scanning electron microscopy ; Thickness measurement ; Tubes (components) ; X ray diffraction ; Failure (mechanical)
  8. Source: Journal of Materials Engineering and Performance ; Volume 22, Issue 9 , 2013 , Pages 2691-2697 ; 10599495 (ISSN)
  9. URL: http://link.springer.com/article/10.1007%2Fs11665-013-0567-2