Adsorption-catalytic method for reducing the content of sulphur compounds in gas condensate diesel fuel

Abstract

Gas condensate diesel fuels, being an excellent resource base, often do not meet modern standards of the cetane number value and the content of sulfur compounds (SC). Currently, Euro 5 and Euro 6 (<10 ppm sulfur content) diesel motor fuels are produced worldwide. High-quality diesel fuels are produced using hydro desulfurization process. Analysis of scientific publications has shown that the adsorption is effective method of desulphurization, which can serve as a method of removing SC from fuels or refining oil and its fractions, which allows removing residual sulfur. The advantages of the adsorption method are: low level of capital costs; simplicity of equipment; carrying out the process under much milder conditions compared to hydro desulfurization. In this paper, an original adsorption-catalytic method of reducing the concentration of SC to <10 ppm using a nanoporous adsorbent-catalyst is proposed. The structure and content of complex sulfur compounds in gas condensate fuels obtained from the raw materials of two deposits – Yamburgsky and Zapolyarny – were determined by gas chromatography–mass spectrometry. The next SC substances were found: tert-hexadecanethiol (C16H34S); 4,4,6-trimethyl-5-phenyl-1,3-oxazinane-2-thione (C13H17NOS); 1,2-bis(2-methylundecan-2-yl)-disulfane (C24H50S2); 3-methyl-2,4a,9,9a-tetrahydro-1H-2λ4-indeno [2,1-c]thiopyran-2-carbonitrile (C14H15NS) and 2,3,4,5-pentamethylbenzene-sulfoneamide (C11H17NO2S). Three-dimensional images of SC molecules and their adsorption complexes with Al-Ni-Mo-O component of a complex adsorbent-catalyst were obtained by molecular modeling. The adsorption energies of SC on the Al-Ni-Mo-O catalyst are calculated. The obtained values of the adsorption energies are in the range of −99.17 ÷−231.66 kJ/mol. As a result of the conducted research, a cartridge with selected adsorbent catalysts has been developed, which must be activated by heating in an inert medium up to 350 ° C. The average life of the cartridge is 1.5 years, after which it needs restoration.