Corrosion Science and Technology

The Corrosion Science Society of Korea (한국부식방식학회)
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Corrosion Behavior of Boiler Tube under Circulation Water Conditions in District Heating System

지역난방 시스템의 순환수에 따른 보일러 튜브의 부식 특성

  • Hong, Minki (Department of Materials Science and Engineering, Chungnam National University) ;
  • Cho, Jeongmin (Department of Materials Science and Engineering, Chungnam National University) ;
  • Song, Min Ji (Department of Materials Science and Engineering, Chungnam National University) ;
  • Kim, Woo Cheol (Frontier Research & Training Institute, Korea District Heating Corp.) ;
  • Ha, Tae Baek (Frontier Research & Training Institute, Korea District Heating Corp.) ;
  • Lee, Soo Yeol (Department of Materials Science and Engineering, Chungnam National University)
  • 홍민기 (충남대학교 신소재공학과) ;
  • 조정민 (충남대학교 신소재공학과) ;
  • 송민지 (충남대학교 신소재공학과) ;
  • 김우철 (한국지역난방공사 미래개발원) ;
  • 하태백 (한국지역난방공사 미래개발원) ;
  • 이수열 (충남대학교 신소재공학과)
  • Received : 2018.11.20
  • Accepted : 2018.12.05
  • Published : 2018.12.31
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Abstract

In this study, corrosion behavior of a SA178-A alloy used in the boiler tube of a district heating system was investigated in different environments where it was exposed to pure water, district heating (DH) water, and filtered district heating (FDH) water. After the corrosion test, the surface morphology was examined for observation of the number of pitting sites and pitting area fraction, using a scanning electron microscope. The DH water and FDH water conditions resulted in a lower corrosion potential and pitting potential, and revealed a significantly higher corrosion rate than the pure water condition. The pitting sites in the DH water (pH 9.6) were approximately eighteen times larger than those in the pure water (pH 9.6). Compared to the DH water, the corrosion potential became more noble in the FDH water condition, where iron ions were reduced through filtration. However, the corrosion rate increased in the FDH water due to an increased concentration of chloride ions, which deteriorated the stability of passive film.

Keywords

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Fig. 1 Schematic view of the direct supply and recovery district heating system.

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Fig. 2 Specimen preparation for the corrosion test.

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Fig. 3 Potentiodynamic polarization behavior in pure water and district heating water conditions.

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Fig. 4 Surface morphology of the tested samples: (a) before electrochemical test, (b) pure water at pH 9.6, (c) pure water at pH 10.5, (d) district heating (DH) water at pH 9.6, (e) filtered district heating (FDH) water at pH 9.6, (f) filtered district heating (FDH) water at pH 10.5.

Table 1 Chemical composition of SA178-A (wt%)

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Table 2 Water conditions for potentiodynamic polarization

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Table 3 Potentiodynamic polarization results using Tafel extrapolation

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Table 4 Pitting sites and pitting area fraction for the tested samples after potentiodynamic polarization

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References

  1. H. Lund, B. Moller, B. V. Mathiesen, and A. Dyrelund, Energy, 35, 1381 (2010). https://doi.org/10.1016/j.energy.2009.11.023
  2. Y. S. Chang, S. W. Jung, S. M. Lee, J. B. Choi, and Y. J. Kim, Appl. Therm. Eng., 27, 2524 (2007). https://doi.org/10.1016/j.applthermaleng.2007.02.001
  3. P. A. Ostergaard and H. Lund, Appl. Energ., 88, 479 (2011). https://doi.org/10.1016/j.apenergy.2010.03.018
  4. H. Gadd and S. Werner, Appl. Energ., 106, 47 (2013). https://doi.org/10.1016/j.apenergy.2013.01.030
  5. D. Connolly, H. Lund, B. V. Mathiesen, S. Werner, B. Moller, U. Persson, T. Boermans, D. Trier, P. A. Ostergaard, and S. Nielsen, Energ. Policy, 65, 475 (2014). https://doi.org/10.1016/j.enpol.2013.10.035
  6. H. Lund, S. Werner, R. Wiltshire, S. Svendsen, J. E. Thorsen, F. Hvelplund, and B. V. Mathiesen, Energy, 68, 1 (2014). https://doi.org/10.1016/j.energy.2014.02.089
  7. Y. S. Kim and J. G. Kim, Eng. Fail. Anal., 83, 193 (2018). https://doi.org/10.1016/j.engfailanal.2017.09.014
  8. F. D. Fatah, A. Mostafaei, R. H. Taghani, and F. Nasirpouri, Eng. Fail. Anal., 28, 69 (2013). https://doi.org/10.1016/j.engfailanal.2012.09.010
  9. KS B 6209, Water conditioning for boiler feed water and boiler water (2017).

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  1. 지역난방 냉각수 배관의 용접부 파손 분석 vol.19, pp.6, 2018, https://doi.org/10.14773/cst.2020.19.6.296