Study of vacuum block corrosion state in visbreaking unit JSC "Gazprom neftekhim Salavat"
The paper presents an analysis of the corrosion state the vacuum block of visbreaking unit JSC "Gazprom neftekhim Salavat", provided on the monitoring data during 2012 – 2013 years. Examined steel grades which used at the manufacturing of basic technological equipment of the vacuum unit, (distillation column, ejectors, heat exchangers, tanks, pipelines) and corrosion resistance of them. Given the brief characteristic of technological parameters, analyzed the possible areas of corrosion damage. Results of the analysis of the condensation water from reflux drums and heat exchangers in terms of pH, dissolved iron mass fraction, mass fraction of chlorides. It is shown that the pH value is in the range of 5.5-8.8 units, and the maximum content of total dissolved iron is 8.9 mg/dm3. This article also shows the results of measurement of corrosion rate of the selected aqueous condensate in a laboratory by electrochemical and gravimetric methods. Results were within 0.15-0.2 mm/year. The paper presents survey results of process equipment during the renovation of a visbreaking unit in 2013 – ejectors, barometric and water seal vessels, heat exchangers of 1-4 condensation stages – on presence of traces corrosion and corrosion damage. Based on analysis it was concluded that the state of the equipment is satisfactory, which was confirmed by special tests. Further work presents an analysis of data measuring the thickness of the vacuum unit metal pipe during the 2012 and 2013, according to which the pipe sections in some places have the corrosion rate up to 0.5-3.0 mm/year. Therefore we recommended for the use of pipelines from corrosion-resistant steel in the areas most exposed to corrosion. For integrated and lasting solution to the question of corrosion on the vacuum unit recommended the introduction of chemical engineering corrosion protection with using of reagents.
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chemical-protection technology.; corrosion; corrosion condition; corrosion monitoring; inspection; vacuum unit; visbreaking; вакуумный блок; висбрекинг; коррозионное состояние; коррозионный мониторинг; коррозия; обследование; химико-технологическая защита. DOI 10.17122/ogbus-2014-2-138-150 References to this article (GOST) A.M. Galin, I.F. Sadretdinov, A.S. Alyab’ev. Study of vacuum block corrosion state in visbreaking unit JSC "Gazprom neftekhim Salavat" // Electronic scientific journal "Oil and Gas Business". 2014. №2. P.138-150. URL: http://ogbus.ru/eng/authors/GalinAM/GalinAM_1e.pdf