Vol 63, No 3 (2023)

Data on the extraction of aromatic hydrocarbons and of sulfur- and nitrogen-containing compounds from model systems with selective solvents, ionic liquids, and deeply eutectic solvents are discussed. The results of the extraction treatment of light and heavy vacuum gasoils and of visbreaker and delayed coker gasoils are presented. The extraction treatment of vacuum gasoils and gasoils from secondary oil refining processes allows the sulfur content of the raffinate to be reduced to less than 0.5 wt %, which meets the requirements to marine fuels used in open sea. The treatment of visbreaker and especially delayed coker gasoils is considerably more efficient than that of vacuum gasoils. The degree of removal of nitrogen-containing components and polyaromatic compounds with dimethylformamide or N-methylpyrrolidone as an extractant is higher than that of sulfur-containing compounds.

A number of Russian bitumen samples with the penetration range of 60 to 120×0.1 mm were rheologically investigated in the temperature range of 46–70°C to evaluate their resistance to plastic rutting using relevant oscillatory and rotational rutting parameters. Based on an assessment of correlations between structural and rheological parameters, the best correlations were observed between the Gaestel Colloidal Index (CI) and the rheological parameters R3.2 and tgδ. The study demonstrated that modified bitumen must be used for pavements with extreme (“E”) traffic loading in Russian regions where PG 52 or higher grade binders are required.

In this work, a multicomponent demulsifier package (named BDTXI) was developed for increasing the demulsification performance of the water-in-oil emulsions. Optimized demulsifier formulation consists of three active components (1-butyl-3-methylimidazolium bis (trifluoromethylsulfonyl)imide, dodecyltriemthylammonium chloride, trioctylmethylammonium chloride), xylene, and isopropanol. A positive synergistic effect was observed among the active components of BDTXI. The concentrations of the components of the developed demulsifier package are determined based on obtaining the best synergistic effect. The demulsification efficiency of BDTXI was higher than commercial reagents at any concentration, water content, and temperature. The optimal concentration of BDTXI was 50 ppm, at which its demulsification effectiveness was more than 97%. The developed demulsifier package could adsorb at the oil-water interface, promote the colloidal dissolution of the emulsion layers, and form a hydrophilic surface characterized by a weak structural strength. The demulsification mechanism of BDTXI was based on minimizing the interfacial tension in order to be able to break the film and increase the frequency of droplet collisions. The change in the temperature and water content of the emulsions did not affect the demulsification performance of BDTXI. Moreover, the average reduction in the asphaltene flocculation parameter with the use of BDTXI and commercial reagents was about 19 and 11%. The results of the analysis of the backscattering light intensity, turbiscan stability index, zeta potential, and shear rate of the emulsions in the presence of various demulsifiers showed that BDTXI could separate the water in the emulsions more efficiently and faster than the commercial reagents.

This study proposed and experimentally investigated a novel approach to hydrogenation of light cycle oil (LCO) into components of winter and arctic diesel fuels (DF) environmentally classified as K5 as per the Technical Regulation of the Customs Union (TR CU) 013/2011 “On the requirements for automotive and aviation gasoline, diesel and marine fuels, jet fuels, and heating oils”. The process design involves atmospheric distillation of LCO with EBP 300˚C followed by hydrotreating. Hydrogenates with low concentrations of total sulfur (<10 mg/kg) and arenes (28.6–38.0 wt %) and adequate low-temperature properties (CFPP≤–43˚C) were produced. An assessment of the physicochemical properties of the hydrogenates against applicable regulations for DF properties suggested that these hydrogenates can be effectively used as components of winter and arctic fuels by blending them into hydroisomerization diesel fractions (HIDF) and winter diesel fuels (WDF). An analysis of the main quality characteristics confirmed the feasibility of blending the LCO-derived hydrogenates into winter and arctic diesel fuels. Using GC×GC/MS examination, correlations were found between the hydrogenation process conditions, the physicochemical properties of the hydrogenates, and their detailed hydrocarbon compositions.

The products of catalytic cracking of heavy crude oil from the Ashalchinskoye oil field (the Almetyevsk district of the Republic of Tatarstan, Russia) were characterized. The effects of a Fe2O3 nanopowder catalyst and the presence of supercritical water (SCW) on the composition and structure of these cracking products were investigated. Cracking over 0.01 wt % Fe2O3 nanopowder in a SCW environment was found to enhance the yield of distillates by more than 34 wt % and to reduce the content of resinous asphaltene materials by a factor of 2.1 compared to the initial crude oil. It was further shown that Fe2O3-nanopowder-catalyzed cracking produces coke-like asphaltenes with a low H/C atomic ratio (no higher than 0.75). Reaction rate constants were evaluated for the thermal and catalytic cracking of the heavy oil from the Ashalchinskoye field.

The paper describes a specifically developed novel samarium cobaltate/silicon carbide composite that transforms into a high-performance carbon-resistant catalyst for dry reforming of methane into syngas (DRM). This 30%SmCoO3/70%SiC composite without hydrogen prereduction was tested in DRM at atmospheric pressure and GHSV 15 L g–1 h–1 (of an equimolar CH4–CO2 mixture). During the test, the yields of hydrogen and carbon monoxide reached 92 and 91 mol %, respectively, at 900°C, and 20 and 28 mol % at 700°C. Using XRD, TGA, and SEM examination, zero carbonization of the catalyst surface was demonstrated. It was found that, in the course of DRM, the initial composite transformed into a material that contained silicon carbide, samarium silicate, and samarium oxide, as well as metallic cobalt nanoparticles (<20 nm).

The performance of polyalkyl acrylate additives of various compositions in low-temperature dewaxing of 11 oil fractions differing in the viscosity and content of waxes, aromatic hydrocarbons, and resins was studied. The dewaxing was performed in a methyl ethyl ketone–toluene mixed solvent. For polyalkyl acrylate with pendant C16–10 alkyl chains, the raffinates can be subdivided into three groups with respect to an increase in the yield of dewaxed oils (relative to the process without additives): increase by 12–13, 5–8, and 3–4%. In most cases, introduction into such polymer of 5–30% polar groups (amino ester, amino amide, amide, oligoethylene glycol) allowed the oil yield to be additionally increased.