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Journal of Failure Analysis and Prevention

, Volume 17, Issue 5, pp 825–830 | Cite as

Investigation of Failed Coils from a Steam Boiler

  • David Ifezue
Case History---Peer-Reviewed
  • 108 Downloads

Abstract

This case study presents results of analysis of failed coil samples from a steam-generating boiler. Scanning electron microscope images suggest that the main cause of failure was overheating. Calcium carbonate and calcium phosphate scaling salts probably derived from the water hardness were identified from the energy-dispersive x-ray (EDX) map. The combination of iron oxide and scales was likely to have created an insulating effect resulting in overheating and eventual tube failure. Calcium carbonate and phosphate scales are easily removed by chemical and mechanical methods. However, approximately 9% of the debris consisted of calcium silicate, as identified from the EDX map. Silicate scales adhere strongly to the surface and are not easily removed by chemical and mechanical methods. From the result of this analysis, it was possible to provide the prior information required for satisfactory repair and maintenance of the failed boiler coils.

Keywords

Boiler Scale Iron oxide Corrosion 

References

  1. 1.
    Handbook of Industrial Water Treatment, GE Power and Water, Water and Process TechnologiesGoogle Scholar
  2. 2.
    J.A. Kelly, The Chemistry and Performance Characteristics of Boiler Water Treatment Polymers, CORROSION 2016, paper no. 7400 (NACE, Houston, 2016)Google Scholar
  3. 3.
    J.A. Kelly, T.R. Filipowski, Controlling iron oxide deposition in boiler systems, in TAPPI Engineering Conference (TAPPI September 20, 1978), p. 467Google Scholar
  4. 4.
    J.A. Kelly, M.L. Palmer, Iron oxide deposition—complete system control, in Proceedings, 40th International Water Conference (Engineers Society of Western Pennsylvania, Pittsburg, 1979)Google Scholar

Copyright information

© ASM International 2017

Authors and Affiliations

  1. 1.Global Corrosion Consultancy LtdManchesterUK

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