Hydrogen sulfide and mercaptans dissolved in oil have a negative impact on the rate of corrosion of metal equipment of refineries. The content of hydrogen sulfide in oil is regulated limited. According to the Technical Regulation of the Eurasian Economic Union 045/2017, the content of hydrogen sulfide in oil allowed for circulation should be reduced from 100 to 20 ppm. This tightening requires oil producers to strengthen measures to reduce the background value of hydrogen sulfide, including a significant increase in the use of specific chemical absorbers (H2S - scavengers, most of which are formaldehyde or triazine based compounds.) A negative aspect of the use of H2S-scavengers is the formation of solid polymethylene sulfides - as reaction products, which are subsequently deposited in the equipment of primary oil distillation. Isolated pockets of corrosion develop under the deposits, in addition, the sections of pipe sections are blocked and the drainage lines of separators are clogged, which in turn causes unscheduled stops, repairs and deterioration of the technical and economic indicators of enterprises. The use of other methods of protection against hydrogen sulfide is accompanied by significantly higher costs.
In order to assess the validity of the regulated values of hydrogen sulfide content in oil, Rosneft Oil Company has initiated research aimed at studying the effect of hydrogen sulfide in oil on refining processes, including product quality and corrosion processes. The article presents the results of the first series of laboratory and field experiments. The most large-scale experiment was the organization of the run of oil with an increased content of hydrogen sulfide without the preliminary introduction of H2S-scavengers to two refineries of Rosneft Oil Company. The result indicates that there are no deviations in the key processes of oil refining with a hydrogen sulfide content of up to 80-90 ppm.
References
1. Leont'eva S.A., Podlesnova E.V., Botin A.A. et al., Determination of 1,2,4-trithiolane in oil and petroleum products by gas chromatography (In Russ.), Zhurnal analiticheskoy khimii = Journal of Analytical Chemistry, 2019, V. 74, no. 12, pp. 930-933.
2. Ishmiyarov E.R., Reagenty dlya neftepromyslovoy khimii (neytralizatory serovodoroda, ingibitory soleotlozheniya i bakteritsidy) na osnove poluatsetaley formal'degida (Reagents for oilfield chemistry (hydrogen sulfide neutralizers, scale inhibitors and bactericides) based on formaldehyde hemiacetals): thesis of candidate of chemical science, Ufa, 2016.
