بررسی علل تخریب لوله 8 اینچ فولادی توزیع گاز شهری

نوع مقاله: مقاله پژوهشی

نویسندگان

گروه پژوهش خوردگی فلزات، پژوهشکده حفاظت صنعتی، پژوهشگاه صنعت نفت، تهران، ایران

چکیده

استفاده از لوله‌های ساخته شده از جنس فولاد کربنی در صنایع نفت و گاز به‌خصوص برای انتقال و توزیع گاز تصفیه شده معمول ‌می‌باشد. برای کنترل خوردگی سطح داخلی لوله‌های انتقال گاز مصرفی، رطوبت گاز در واحدهای نم‌زدا حذف می‌شود. به‌علاوه مقدار گاز‌ خورنده CO2 به کمتر از 2% محدود می‌شود. در این تحقیق علل تخریب یک خط لوله فولادی in 8 توزیع گاز مورد بررسی قرار خواهد گرفت. خط لوله مورد نظر به‌مدت 2 سال مدفون و بدون گاز بوده و بعد از آن برای 6 سال در حال بهره‌برداری بوده است. برای تعیین مکانیزم تخریب احتمالی از بررسی‌های ظاهری، میکروسکوپی و همچنین آنالیز‌های شیمیایی همچون EDS و XRD استفاده شد. به‌علاوه از مدل تعیین نرخ خوردگی ناشی از گاز دی‌اکسیدکربن NORSOK جهت تعیین نرخ خوردگی در شرایط بهره‌برداری استفاده شد. نتایج حاصل نشان داد خوردگی ناشی از گاز دی‌اکسید‌کربن محتمل‌ترین دلیل بروز خوردگی داخلی خط لوله مورد اشاره و بروز نشتی است.
 

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Failure Analysis of an 8-inch Urban Gas Distribution Steel Pipeline

نویسندگان [English]

  • Mohammad Shayegani Akmal
  • Amir Pasha
  • Azin Ahmadi
Metal Corrosion Research Group, Industrial Prtection Research Department, Research Institute of Petroleum Industry (RIPI), Tehran, Iran
چکیده [English]

The use of carbon steel is conventional for the transmission and distribution of treated natural gas. In order to control the internal corrosion of the gas transfer pipelines, the moisture content is removed in dehydration unit. In addition, the amount of CO2 gas is limited to less than 2%. In this study, the cause of the failure of an 8-inch gas distribution pipeline is investigated. The pipeline was not in service for two years and then it was in operation for 6 years before the failure. Microscopic examinations, as well as chemical analyzes such as EDS and XRD, were used to determine the possible mechanisms of damage. In addition, the NORSOK CO2 corrosion model was used to determine the corrosion rate in operating conditions. The results showed that corrosion caused by carbon dioxide is the most likely cause of internal corrosion of the pipeline and the occurrence of the leakage.

کلیدواژه‌ها [English]

  • CO2 Corrosion
  • Failure Analysis
  • Carbon Steel
  • Natural Gas
  • Pipeline

[1]. Zou C. J., Zhao P. W., Wang M., Liu D. L., Wang H. D. and Zhang W., “Failure analysis and faults diagnosis of molecular sieve in natural gas dehydration,” Eng. Fail Anal., Vol. 34, pp.115-120, 2013.##

[2]. Mokhatab S., Poe W. A. and Mak J. Y., “Handbook of natural gas transmission and processing,” 3rd ed., Elsevier Science & Technology, 2015.##

[3]. Fontana M. G., “Corrosion engineering,” 3rd ed., McGraw-Hill Book Company Inc., pp. 1-197, 1987.##

[4]. De Waard C., Lotz U. and Dugstad A., “Influence of liquid flow velocity on CO2 corrosion: a semi-empirical model,” Corrosion, Vol. 95, Orlando, No.128, 1995.##

[5]. Kermani M. B. and Morshed A., “Carbon dioxide corrosion in oil and gas production-a compendium,” Corrsion, Vol. 59, pp. 659–683, 2003.##

[6]. Little B. J., Lee J. S., “Microbiologically influenced corrosion,” John Wiley & Sons, Inc., 2007.##

[7]. Barton LL., “Sulfate-reducing bacteria,” Kluwer Academic Publishers, 1995.##

[8]. Little B. J., Wagner P. and Mansfeld F. B., “Microbiologically influenced corrosion of metals and alloys,” Int. Mater. Rev., Vol. 36, No. 20, pp. 253–272, 1991.##

[9]. ASTM  E407, “Standard practice for microetching metals and alloys,” ASTM International, 2007.##

[10]. ASTM  E415, “Standard test method for atomic emission vacuum spectrometric analysis of carbon and low-alloy steel,” ASTM International, 2008.##

[11]. Sherman R. E., “Analytical instrumentation: practical guides for measurement and control,” Instrument Society of America, 1996.##

[12]. ASTM G1, “Standard practice for preparing, cleaning, and evaluating corrosion test specimens,” ASTM International, 2003.

[13]. API 5L, “Specification for line pipe,” American Petroleum Institute, 2013.##

[14]. Javaherdashti R., “Microbiologically influenced corrosion: an engineering insight,” Springer, 2008.##

[15]. API 570, “Piping inspection code: in-service inspection, rating, repair, and alteration of piping system,” 2009.##

[16]. Norsok M-506, “CO2 corrosion rate calculation model,” Norwegian Standard, 2005.##

[17]. Little B. J., Lee J. S. and Ray R. I., “Diagnosing microbiologically influenced corrosion: a state-of-the-art review,” Corrsion, Vol. 62, No. 11, pp. 1006-1017, 2006.##

[18]. IGS-M-CH-38, “Odorant to be used for odorization of natural gas,” Iranian Gas Standards, 2009.##

[19]. Kobrin, G., “Reflexions on microbiologically induced corrosion of stainless steels,” Proceedings of International Conference on Biological Induced Corrosion,  In: Dexter S.C. (Ed.), National Association of Corrosion Engineers, Houston, TX, pp. 33-46, 1986.##

[20]. Becker W.T., Shipley R.J., “Failure analysis and prevention,” Metals Handbook, Vol. 11, 9th ed. ASM International, 2002.##

[21]. During E.D.D., “Corrosion atlas,” Elsevier Science, 1997.

[22]. Zhao G., Lv X., Li H. and Lu M., “Effect of temperature on CO2 corrosion behaviour of P110 steel,” J. Chin.Soc. Corr. Pro., Vol. 25, No. 2, pp 93-96, 2005.##

[23]. Pandarinathan V., Lepková K. and Bronswijk W., “Chukanovite (Fe2(OH)2CO3) identified as a corrosion product at sand-deposited carbon steel in CO2-saturated brine,” Corros. Sci., Vol. 85, pp 26-32, 2014.##

[24]. Azoulay I., Rémazeilles C. and Refait Ph., “Corrosion of steel in carbonated media: The oxidation processes of chukanovite (Fe2(OH)2CO3),” Corros. Sci., Vol. 85, pp 101-108, 2014.##

[25]. Shi L., Wang C. and Zou C., “Corrosion failure analysis of L485 natural gas pipeline in CO2 environment,” Eng. Fail Anal., Vol. 36, pp 372–378, 2014.##