Root causes analyzed of leakage on the tank bottom using simulation cathodic protection

Subject Areas : journal of New Materials

Mohammad Houshmand ¹ , Ali Davoodi ² , Mehrdad Kashefi Torbati ³

1 - Metallurgy Department, Ferdowsi University of Mashhad
2 - Metallurgy Department, Ferdowsi University of Mashhad
3 - Metallurgy Department, Ferdowsi University of Mashhad

Received: 2019-05-07 Accepted : 2019-07-01 Published : 2019-06-22

Keywords: Finite element method, cathodic protection simulation, potential distribution,

Abstract :

in this paper, cause of leakage on the caustic tank bottom is investigate using simulation cathodic protection and develop the NACE formula “current distribution with a close anode-to-structure spacing”. The Finite Element Method is used for numerical solution. Although, field measurements have been under protection of the tank bottom, However, the simulation results showed that only a limited area of the tank bottom was protected, which this area follows the NACE formula and the surrounding areas of the tank have a lower level of protection, that has led to the leakage this areas. There were many ways to increase the protection area, one of them was an increase the anode distance from the tank bottom that the NACE formula indicating this issue but the simulation results showed the opposite of this. Each anode make a potential gradient that can vary from one anode to another. Therefore, NACE formula can be used until; with increase anode distance from tank bottom, tank bottom don’t get out from anode potential gradient. For this reason, in this paper, the NACE formula has been developed by providing a complementary formula and using the specified condition, which has a higher efficiency than the previous formula.

References:

 

[1] P.A. Collins, K.C.Garrity, C.J. Pieper, R.P. Siegel, P.J. Smith, G.E.Tesch (Eds.), Aboveground Storage Tanks: Current Issues––Design, Operations, Maintenance, Inspection and the Environment, NACE, Houston, TX, 1992.

[2] US EPA, Title40 code of federal regulations, parts 280 and 281, September 1988.

[3] L.Koszewski, Retrofitting asphalt storage tanks with an improved cathodic protection system, Materials Performance 38 (6) (1999) 20–24.

[4] E. Kurgan, “Influence of electrolyte conductivity on cathodic protection with sacrificial anode,” ActaTechnica CSAV, vol.49, 365-382, 2004(4).

 

[5] R. G. Kasper, M. G. April, Corrosion 1983, 39, 181.

 

[6] D.P. Riemer, M.E. Orazem, Corros. Sci. 47 (2005): p. 849-868.

 

[7] C.A. Brebbia, J. Dominguez, Boundary element methods for potential problems, Applied Mathematical Modelling 1 (7) (1977) 371–378.

[8] S. Aoki, K. Kishimoto, M. Sakata, Boundary element analysis of galvanic corrosion, in: C.A. Brebbia, G. Maier (Eds.), Boundary Elements VII, vol. 1, Springer-Verlag, Heidelberg, 1985, pp. 73–83.

[9] J.C.F. Telles, W.J. Mansur, L.C. Wrobel, M.G. Marinho, Numerical simulation of a cathodicallyprotected semisubmersible platform using the procat system, Corrosion 46 (6) (1990) 513–518.

[10] N. Zamani, J. Chuang, Optimal-control of current in a cathodic protection system––a numerical investigation, Optimal Control Applications Methods 8 (4) (1987) 339–350.

[11] F. Brichau, J. Deconinck, Numerical model for cathodic protection of buried pipes, Corrosion 50 (1) (1994) 39–49.

[12] F. Brichau, J. Deconinck, T.Driesens, Modeling of underground cathodic protection stray currents, Corrosion 52(1996) 480–488.

[13] S. Aoki, K. Amaya, Optimization of cathodic protection system by BEM, Engineering Analysis with Boundary Elements 19 (2) (1997) 147–156.

[14] S. Aoki, K. Amaya, M.Miyasaka, Boundary element analysis of cathodic protection for complicated structures, in: M.E. Orazem (Ed.), Proceedings of the NACE99 Topical Research Symposium: Cathodic Protection: Modeling and Experiment, NACE, NACE International, Houston, TX, 1999, pp. 45–65.

[15] D.P. Riemer, M.E. Orazem, Application of boundary element models to predict effectiveness of coupons for assessing cathodic protection of buried structures, Corrosion 56 (8) (2000) 794–800.

[16] A. Demoz, W. Friesen,Corrosion 64, 2 (2008): p. 138-142.

 

[17] B. Bazzoni, S. Lorenzi, P. Marcassoli, and T. Pastore, “Current and Potential Distribution Modelingfor Cathodic Protection of Tank Bottoms,” corrosion—Vol. 67, No. 2 (2011)

 

[18] A.W. Peabody, “Control of Pipeline Corrosion,” 2nd ed., Beijing:Chemical Industry Press, 2004, pp5-6, 21-46.

 

[19] Comsol Multiphysics 5.2a, Application Library, Corrosion Module/Cathodic Protection.

 

[20] R.D. Strommen, R.S. Munn (Eds.), Computer Modelling in Corrosion, ASTM STP 1154, Philadelphia, PA, USA, 1992, pp. 229–447.

 

[21] R.S. Munn, O.F. Devereux, Numerical modelling and solution of galvanic corrosion systems 1. Governing differential-formula and electrodicboundaryconditions, Corrosion 47 (1991) 612–618.

 

[22] J.X. Jia, G. Song, A. Atrens, D.S. John, J. Baynham, G. Chandler, Evaluation of the BEASY program using linear and piecewise linear approaches for the boundary conditions, Mater. Corros. 55 (2004) 845–852.

 

[23] A. Canelas, J. Herskovits, J.C.F. Telles, Shape optimization using the boundary element method and a SAND interior point algorithm for constrained optimization, Comput. Struct. 86 (2008) 1517–1526.

 

[24] V.G. DeGiorgi, S.A. Wimmer, Geometric details and modelling accuracy requirements for shipboard impressed current cathodic protection system modelling, Eng. Anal. Boundary Elem. 29 (2005) 15–28.

 

[25] S.H. Lee, D.W. Townley, K.O. Eshun, A boundary element model of cathodic well casing protection, J. Comput. Phys. 107 (1993) 338–347.

 

[26] R. Montoya, O. Rendón, J. Genesca, Mathematical simulation of cathodic protection system by finite element method, Mater. Corros. 56 (2005) 404– 411.

[27] P. Lambert, P.S. Mangat, F.J. O’Flaherty, Y.-Y. Wu, Influence of resistivity on current and potential distribution of cathodic protection systems for steel framed masonry sructures, Corros. Eng. Sci. Technol. 43 (2008) 16–22.

[28] A. J. Denny, Principles and prevention of corrosion, Prentice Hall, New York 1996, 440 – 449.

 

[29] R. D. Strommen, In: Computer Modeling in Corrosion (Ed.R.S. Munn), STP 1154, ASTM, Philadelphia 1992, 229 – 447.

 

[30]Dhatt G, Touzot G. Finite element method. John Wiley & Sons; 2012 Dec 27.

[31]Zienkiewicz OC, Taylor RL, Zienkiewicz OC, Taylor RL. The finite element method. London: McGraw-hill; 1977.

[32] G. Gabetta, "Transgranular stress corrosion cracking of low-alloy steels in diluted solutions," Corrosion, 1997, Vol. 53, pp. 516-524.

 

[33] NACE International, Cathodic Protection Technologist, NACE, 2005, 4:68 – 4:70.

 

[34] A.W. Peabody, "Peabody’s Control of Pipeline Corrosion," NACE International, 2011, Second Edition, pp. 29-33.