Composition and main properties of the solid phase of deposits on the inner surface of the tanks with sulfurous oil

Purpose. Russia is one of the top three world leaders in oil production and refining. Currently, Russia's tank farm has more than 50,000 tanks located on the territory of approximately 660 tank farms. Tank farms have equipment of varying degrees of wear, which leads to periodic equipment failure, sometimes an emergency one, accompanied by explosions and fires, whose number increases over time. One of the frequent causes of fires and explosions of oil tanks is the formation of pyrophoric deposits on their inner surface, which interacts with the vapour-gas environment. In this case, the pyrophoric deposit is the source of ignition. Until now, there is no information regarding the relationship between the phase composition and properties of the solid phase of deposits and their pyrophoric capacity. The main objective of the work is to determine the characteristics of the solid phase of deposits formed on the internal surface of oil tanks, which interacts with the vapour-gas environment. Methods. The X-ray phase analysis method was used to determine the characteristics of the solid phase of deposits on the inner surface of oil tanks. The experimental results were obtained using an experimental method consisting in the complex application of optical microscopy, gravimetry, and densitometry. Findings. The following characteristics were determined: phase composition, density, porosity, specific surface area of the solid phase of deposits formed on the inner surface of oil tanks, which interacts with the vapour-gas environment. Research application field. The results can be used in planning and implementing anti-corrosion protection of bulky equipment at oil and gas industry facilities. Conclusions. It has been established that the solid phase of deposits in various proportions, independent of the type of stored oil, may include sulfur (with a predominance of orthorhombic), iron monosulfide FeS, iron disulfide FeS2, hematite Fe2O3, goethite FeO(OH), lepidocrocite Fe3+O(OH).