Materials Performance

DEC 2014

Materials Performance is the world's most widely circulated magazine dedicated to corrosion prevention and control. MP provides information about the latest corrosion control technologies and practical applications for every industry and environment.

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71 NACE INTERNATIONAL: VOL. 53, NO. 12 MATERIALS PERFORMANCE DECEMBER 2014 Monitoring Pipelines for Microbiologically Influenced Corrosion FIGURE 6 A deep corrosion pit in a sample from a ruptured pipe segment. DNA was recovered from the pit in this dried pipe segment. DNA unless the sample is obtained from a deep pit protected by corrosion deposits (Figure 6). Genetic tests showed that ~10 6 cells/cm 2 of total bacteria as well as ~10 4 cells/mL of SRB were present in the sample obtained from the pit shown in Figure 6. The deep undercut pitting in this pipe seg ment probably provided protection of the bacteria/DNA in this sample. Conclusions Microbiological testing is an important component in pipeline monitoring/main tenance programs. Care must be taken, however, to analyze samples as quickly as possible when microbial growth tests are performed, and collecting multiple com posited samples is recommended when heterogeneous material such as pig returns are being sampled. Genetic tests can detect DNA from living and dead bacteria, and can be used to test for the presence of corro sionassociated microorganisms on sam ples where microbial growth tests can't be used , such as old pipe segments. DNA degrades in the environment, however, and even genetic testing may be ineffective if pipe samples have been removed from ser vice for more than a month. It is important to obtain comprehensive data when determining the corrosion mech anism in any given sample. Physical and chemical tests, in addition to microbiologi cal/genetic tests, should be used. Micro scopic examination of the morphology of corrosion pits, chemical analysis of corro sion products, m etallurgical analyses, microbiological analyses, as well as the oper ating conditions and composition of the fluid in the pipe during service, should all be considered when making a determination regarding the likely corrosion mechanism. References 1 G.H. Koch, M.P.H. Brongers, N.G. Thompson, Y.P. Virmani, J.H. Payer, "Corrosion Costs and Preventive Strategies in the United States," Federal Highway Administration, FHWA RD01156, 2001. 2 NACE TM01942013, "Field Monitoring of Bacterial Growth in Oil and Gas Systems" (Houston, TX: NACE International). 3 X.Y. Zhu, J.J. Kilbane, II, "Faster and More Ac curate Data Collection for Microbiologically Inf luenced Corrosion," SPE International Symposium on Oilfield Chemistry, paper no. SPE93089PP (Richardson, TX: SPE, 2005), pp. 19. 4 X.Y. Z hu , J. Lubeck, K. Lowe, A. Daram , J.J. Kilbane, II, "Improved Method for Moni toring Microbial Communities in Gas Pipe lines," CORROSION 2004, paper no. 04592 (Houston, TX: NACE, 2004). 5 P.J.B. S cott, "E xpert Consensus on MIC: Prevention and Monitoring—Part 1," MP 43, 3 (2004): pp. 5054. This paper is based on CORROSION 2014 papers no. 3788 and 3789, presented in San Antonio, Texas. JOHN J. KILBANE is the program manager, petroleum microbiology, at Intertek We s t p o r t Te c h n o l o g y C e n t e r, 6 7 0 0 Portwest Dr., Houston, TX 77024, e-mail: j o h n . k i l b a n e @ i n t e r t e k . c o m . H e h a s devoted his 30-year career to the applica- tion of biotechnology to various topics in the energy industry. Research topics have included the detection and control of MIC, biodesulfurization of petroleum, convert- ing waste materials into biofuels (methane, ethanol, and biodiesel), and the remedia- tion of hydrocarbon-contaminated soil and water. Prior to joining Intertek, Kilbane worked for the biofuels company Qteros, the Gas Technology Institute in Chicago, and is a professor of biology at the Illinois Institute of Technology. He has a Ph.D. in microbiology & molecular biology from Tufts University and is a member of NACE International.

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