Transformation of sulphur-containing compounds during simulated desulphurisation using catalyst precursors and an alkali metal suspension
R. E. MUKHAMATDINOVA, I. I. MUKHAMATDINOV, D. A. FEOKTISTOV, S. A. SITNOV, G. KH. SITDIKOVA, YA. V. ONISHCHENKO, S. A. TRUBITSINA, V. E. KATNOV, A. V. VAKHIN
Kazan (Volga Region) Federal University, Institute of Geology and Petroleum Technologies, Kazan, Russia
Keywords: desulphurisation, sodium organodispersion, catalyst precursor, sulphur-containing compounds
Abstract
Desulphurisation remains a critical focus of petroleum processing research, as sulphur-containing compounds are present in the majority of crude oils, degrade the quality of petroleum products and have a detrimental impact on the environment. The effect of oil-soluble catalyst precursors based on the tallates of iron, nickel, cobalt and chromium in a petroleum-based solvent (nefras-С4-155/205, white spirit) with the addition of a suspension of alkaline metal on the transformation of sulphur-containing compounds during simulation of desulphurisation processes was assessed. Thiophene and diphenyl sulphide were used as model systems, subjected to high-temperature aquathermolysis at 150 and 250 °C, in the presence of a commercial form of oil-soluble catalyst precursors based on tallates of iron, nickel, cobalt and chromium in the solvent (nefras) with and without the addition of sodium suspension in vaseline oil. The reaction products were analysed using gas chromatography and mass spectrometry, the concentrations of sulphide and mercaptan sulphur in aqueous products were determined via titration in accordance with GOST R 56871-2016, the phase composition of the catalysts and resulting solid products was examined using X-ray diffraction analysis. The results demonstrate that the model systems are transformed under the action of reagents. The interaction of thiophene with sodium leads to the formation of butene-2, butanone-2, methylheptadienes, dimethylheptane, octadienes, and dodecadienes. The reaction of sodium with diphenyl sulphide yields benzene and thiobenzene. The X-ray diffraction analysis of the post-reaction catalysts after autoclave experiments with thiophene and diphenyl sulphide revealed the formation of metal sulphides, sulphates, and oxides, thus confirming the occurrence of desulphurisation. The findings can be put to practical use in further studies of desulphurisation processes in crude oil and petroleum products.
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