Abstract: High-sulfur petroleum coke, produced as a distillation by-product in production of motor fuels by delayed coking of heavy petroleum residues, is widely used in power engineering and in other practical applications. However, the large-scale use of petroleum coke in the energy and metallurgy industries is accompanied by significant emissions of sulfur compounds into the environment, which leads to high and very high levels of air pollution in cities where such production is localized. The sulfur content in the original coke (more than 1.5% for sulfur cokes and more than 4% for high-sulfur cokes) is determined mainly by the sulfur content in the feedstock, as well as the influence of technological parameters of the coking process. Sulfur is present in petroleum coke mainly (up to 98%) as part of organosulfur compounds and is represented mainly by thiophene, dibenzothiophene and their alkyl derivatives (~2% of sulfur is represented by inorganic compounds in the form of sulfates and sulfides of metals and elemental sulfur). The presence in the original petroleum coke of condensed compounds such as thiophene and other organosulfur compounds associated with the carbon skeleton of the coke makes it difficult to remove sulfur, and currently desulfurization of high -sulfur coke is a great challenge. No economical method has yet been found to achieve efficient and cost-effective desulfurization of high-sulphur petroleum coke on an industrial scale. This project presents a new approach to creating an effective, environmentally friendly and economical process based on the use of the hydrothermal method of oxidative desulfurization of petroleum coke by oxidation with oxygen (air) in aqueous solutions at elevated temperatures (110-250°C). Hydrothermal oxidation technologies allow complete oxidation of various sulfur compounds both without catalysts and, under milder conditions, in the presence of catalytic systems [1, 2]. The dependences of the degree of desulfurization on the parameters of the process were experimentally determined. The highest degree of desulfurization at an oxygen pressure of 5.0 MPa and 180°С was from 32.34 (at the petroleum coke particle size of 2 mm) to 39.68% (at the petroleum coke particle size smaller than 0.5 mm). The maximal degree of desulfurization, reached at an oxygen pressure of 5.0 MPa, 220°С, and petroleum coke particle size smaller than 0.5 mm, was 51.61%. CONCLUSIONS Our study proved the possibility of reaching high degrees of desulfurization (up to 50%) in a one-step oxidation process performed in an aqueous phase under excess pressure corresponding to or exceeding the saturated water vapor pressure. The desulfurizing agent in the process is atmospheric oxygen or pure oxygen under the conditions ensuring efficient mass transfer of the desulfurizing agent to the petroleum coke surface. The optimum parameters of the oxidative desulfurization are as follows: Т = 180°C, Р = 5 MPa, and coke particle size 1–2 mm. The resulting low-sulfur desulfurization product can be used in the energy sector, in metallurgy, in particular, at coke-chemical enterprises in the composition of the charge for producing metallurgical coke. REFERENCES 1. Dobrynkin N.M., Batygina M.V., Kapustin V.M., Russian Journal of Applied Chemistry. 2022. V.95. N9. P.1297–1303. 2. Dobrynkin, N.M., Batygina, M.V., and Noskov, A.S., Chem. Eng. Trans., 2010, V. 23, P. 339–344. The study was financially supported in part by the Novolipetsk Metallurgical Combine (Russia) and Ministry of Science and Higher Education of the Russian Federation within the framework of the government assignment for the Boreskov Institute of Catalysis, Siberian Branch, Russian Academy of Sciences.

Cite: Dobrynkin N. , Batygina M. , Noskov A.
Desulfurization of High‑Sulfur Petroleum Coke by Wet Oxidation with Oxygen (Air) under Mild Conditions
In compilation Sino-Russian symposium on reducing emissions and improving the environmental component of the energy industry : Сollection of works. – Gubkin University., 2024. – C.42-43. – ISBN 978-5-91961-519-4. РИНЦ

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