The transformations of oil components from the Zyuzeevskoye field during catalytic aquathermolysis in the presence of a nickel-containing catalyst precursor and hydrogen donors were studied. It was found that the yield of gasoline and diesel fractions increased by more than 36% in the case of catalytic aquathermolysis in the presence of tetralin. The maximum conversion of asphaltenes was achieved with a simultaneous slowing down of coke formation by four times. The calculation of the structural-group parameters of initial asphaltenes and the products of thermal cracking and catalytic aquathermolysis was made, and the hypothetical construction of their molecular structures was proposed. It was established that the phase composition, ratio, and morphology of nickel catalysts after catalytic aquathermolysis (CA) and catalytic aquathermolysis with tetralin (CA+T) depend on the amount of “free” hydrogen and are represented by Ni_0.96S and Ni₉S₈.

The aim of this work was to study the fractional composition of super-viscous oil resins from the Ashalcha field, as well as the catalytic aquathermolysis product in the presence of a cobalt-containing catalyst precursor and a hydrogen donor. The study was conducted at various durations of thermal steam exposure. In this regard, the work enabled the identification of the distribution of resin fractions. These fractions, obtained by liquid adsorption chromatography, were extracted with individual solvents and their binary mixtures in various ratios. The results of MALDI spectroscopy revealed a decrease in the molecular mass of all resin fractions after catalytic treatment, mainly with a hydrogen donor. However, the elemental analysis data indicated a decrease in the H/C ratio for resin fractions as a result of removing alkyl substituents in resins and asphaltenes. Moreover, the data of ¹H NMR spectroscopy of resin fractions indicated an increase in the aliphatic hydrogen index during catalytic aquathermolysis at the high molecular parts of the resins R3 and R4. Finally, a structural group analysis was carried out in this study, and hypothetical structures of the initial oil resin molecules and aquathermolysis products were constructed as well.

Structural changes of asphaltenes in the course of thermal and catalytic cracking of heavy oil from the Zyuzeevskoye field in the Republic of Tatarstan wer

The paper presents the results of investigation of changes in the composition of hydrocarbons and sulfur-containing compounds of an atmospheric residue in the course of cracking in the presence of a tungsten carbide–nickel–chromium (WC/Ni–Cr) catalytic additive and without it. The cracking is carried out in an autoclave at 500 °C for 30 min. The addition of the WC/Ni–Cr additive promotes the deepening of reactions of destruction not only of resins and asphaltenes, but also high molecular weight naphthene-aromatic compounds of the atmospheric residue. It is shown that the content of low molecular weight C₉–C₁₇ n-alkanes and C₉–C₁₀ alkylbenzenes rose sharply in the products of cracking with addition of WC/Ni–Cr in comparison with those produced without the additive. Alkyl- and naphthene-substituted aromatic hydrocarbons of benzene, naphthalene, phenanthrene series, polyarenes, benzo- and dibenzothiophenes are identified.

The work deals with study the effect of the NiCrWC catalyst on the composition of the products of catalytic cracking of heavy oil at a temperature of 450 °C for 100 minutes is established. The relevance of research aimed at studying the catalytic activity in the processing of heavy oil. It has been installed that the addition of NiCr-WC promotes the retardation of coke and asphaltenes formation and an increase in the destruction of high-molecular components of heavy oil. The use of a catalyst makes it possible to increase the yield of gasoline and diesel fractions by 35.8 wt % compared to the initial oil. Due to the formation of gaseous products, the removal of 2 wt % of sulfur from oil is observed. The data of X-ray phase analysis and scanning electron microscopy show that metal oxides are sulfidized on the surface of nichrome particles to form sulfides of these metals. It was found that Ni_xS_y and Cr_xS_y formed on the catalyst surface contribute to an increase in the degradation of oil resins and asphaltenes.

The work deals with the study of high molecular weight components of oils, namely with asphaltenes. The relevance of research aimed at studying the structural changes and thermal properties of asphaltenes under the conditions of heavy residual feedstock processing increases every year. It has been shown that the addition of NiCr-WC promotes the retardation of gas formation and an increase in the destruction of resins and asphaltenes of the vacuum residue.The average diameter of the aromatic layers (L_a) increases from 8.10 to 10.58 Å in the cluster and decreases the number of aromatic layers in a cluster (M) and the average height of a cluster of aromatic layers (L_c) from 7.58 to 5.09 and 26.70 to 18.34 Å respectively in the series ‘initial asphaltenes – asphaltenes after thermal processing – asphaltenes after thermocatalytic processing. Based on differential scanning calorimetry in the temperature range 400–700 °C, the destruction of asphaltenes is accompanied not only by the formation of low molecular weight hydrocarbon structures but the intensive removal of heteroatoms (S and N).