Fig. 1 Example of test APEC indications on buried pipes of from brochure of Structural Integrity Associate, Inc. [4].
Fig. 2 Geometric model of an anode and pipes.
Fig. 3 Mesh generation of an anode and pipes.
Fig. 4 Electrolytic potential distribution on buried pipes (applied current: 0.025 A).
Fig. 5 Electrolytic potential distribution on earth surface; (a) 3D plot, (b) 2D plot.
Fig. 6 Geometric design for detecting defect locations on buried pipes.
Fig. 7 Electrolytic potential distribution on earth surface and plane of incidence.
Fig. 8 Electrolytic potential distribution on a plane of incidence; (a) 2D plot, (b) 1D plot.
Fig. 9 Geometric realization for defect locations comparison and defects size calculation.
Fig. 10 Comparison between locations of a real defect and expected defect after modeling; (a) Electrolytic potential of earth surface and buried pipes, (b) Comparison of defect locations (right), (c) Comparison of defect locations (left).
Fig. 11 Current density curve on buried pipe with defects.
Table 1 Governing equation of the secondary current distribution
Table 2 Parameters for simulation runs
References
- EPRI 1016456, Recommendations for an Program to Control the Degradation of Buried and Underground Piping and Tanks, Revision 1 (2010).
- KISTEK, Development of corrosion environment survey and analysis method for buried pipe II (1999).
- KOGAS, Protection technique handbook, p. 18 (2003).
- EPRI 1022962, Plant Engineering: Evaluation of Indirect Assessment Techniques for Coating Flaw Detection (2011).
- H. Y. Chang, H. B. Park, K. T. Kim, Y. S. Kim, and Y. Y. Jang, KPVP, 11, 61 (2015).
- H. Y. Chang, K. T. Kim, B. T. Lim, K. S. Kim, J. W. Kim, H. B. Park, and Y. S. Kim, Corros. Sci. Tech., 16, 115 (2017).
- Elizabeth Nicholson, B.Eng., Coatings and Cathodic Protection, http://www.cath-tech.com (2012).
- COMSOLTM, Guidebook of COMSOLTM Multiphysics (Chemistry-Electrochemistry), p. 174, ALTSOFT (2014).