One of the possible applications of supercritical water is the conversion of heavy hydrocarbon feedstocks with a high content of resins and asphaltenes. The use of supercritical water makes it possible to reduce the yield of solid products and increase the yield of light fractions. In this work, a comparative analysis of the cracking processes of petroleum residue, asphaltenes and resins isolated from it was carried out in an environment of supercritical water and without water. The experiments were carried out in an autoclave at a temperature of 450 degrees & Scy; and a pressure of up to 47 MPa. Cracking duration - 60 min. Cracking of petroleum residue, as well as its individual components - resins and asphaltenes, in a supercritical water environment- showed a positive effect on conversion; in all experiments, the yield of solid products decreased and the yield of maltenes increased. Solid products were studied using X-ray diffraction and thermogravimetric analysis and scanning electron microscopy. Using X-ray diffraction analysis, the influence of supercritical water on the parameters of the macrostructure was studied. It was determined that cracking with water affects the increase in the distance between saturated fragments of molecules (dr) in the structure of solid cracking products in comparison with products obtained without water. Using scanning electron microscopy, the surface of particles of insoluble cracking products was characterized. Solid products obtained in a supercritical water environment have a porous surface. According to thermal analysis data, it is shown that solid products obtained by cracking in water are characterized by more intense dynamics of sample weight loss and a smaller residue at the final temperature.

The composition and characteristics of high-molecular-weight components of the thermolysis products of petroleum residue asphaltenes obtained in supercritical water with and without a catalyst based on iron oxides have been studied. The experiments were carried out in an autoclave at a temperature of 450°C for 60 min; the catalyst was prepared in situ from iron(III) tris(acetylacetonate). The use of supercritical water and the in situ prepared catalyst made it possible to increase the yield of saturated and aromatic hydrocarbons by a factor of more than 9.5 compared to that in a control experiment (thermolysis without water and a catalyst) and decrease the yield of solid products insoluble in chloroform. The properties of high-molecular-weight components isolated from the thermolysis products were characterized using structural group analysis and IR spectroscopy. High-molecular-weight components obtained by thermolysis in supercritical water in the presence of the catalyst, in comparison with the products obtained in the control experiment, were characterized by higher H/C ratios and concentrations of oxygen-containing groups and lower average molecular weights.

The use of supercritical water is a promising way to transform heavy oil feedstock into light products. Heavy hydrocarbon raw materials are characterized by a high content of high-molecular components, which make processing difficult. The upgrading of asphaltenes and heavy oil residue resins in supercritical water was studied using an autoclave reactor. The experiments were carried out at a temperature of 450 degrees C, the duration was 60 min, and the pressure was 4.7 MPa. The reactivity and structural changes of resins and asphaltenes were evaluated from the yield of products (gas, oils, resins, asphaltenes, and solid products) and the characteristics of the initial and thermally treated high molecular weight compounds (resins, asphaltenes) using a structural group analysis. For maximum conversion, a catalyst precursor, iron(III) tris-acetylacetonate, was used, which forms catalytically active iron oxides upon thermolysis. The positive effect of supercritical water on the conversion of resins and asphaltenes has been shown. The use of supercritical water makes it possible to reduce the yield of solid products and increase the yield of light products. In the presence of a catalyst, asphaltenes turned out to be more reactive than resins. Thermolysis using supercritical water leads to changes in the parameters of the macrostructure of residual resins and asphaltenes. During the thermolysis of resins in the presence of water, the number of structural blocks in the molecule in the secondary resins decreases, and the number of heteroatoms increases compared to the initial resins. The use of iron oxides contributes to a significant increase in the H/C ratio in secondary asphaltenes obtained by thermolysis of asphaltenes. The number of struc-tural blocks decreased by 2 times.

The aim of the work is to evaluate the effect of sunflower oil additives in oil residues on the structure of the formed asphaltenes and coke in the cracking process. Cracking of oil residues and their mixtures with sunflower oil in various ratios is carried out. Comparison of the data of X-ray structural analysis of asphaltenes and coke isolated from products of cracking is performed. The analysis showed that the addition of sunflower oil to oil residues leads to changes in the parameters of the macrostructure of asphaltenes and coke obtained in products of cracking. In coke isolated from products of cracking obtained in the presence of sunflower oil, the height of the stack of aromatic sheets (Lc) increases, while the distance between the aromatic layers (dm) does not change significantly. In asphaltenes isolated from products of cracking, the average diameter of the aromatic sheets (La) and the distance between saturated structures (dr) vary significantly. The role of sunflower oil is explained by the participation of triglyceride degradation products (mainly fatty acids and olefins) in condensation processes, which makes it possible to reduce the yield in coke and asphaltenes.

The thermolysis of brown coal was carried out at temperatures of 360 and 380°C in water without a catalytic additive and in the presence of a catalyst based on iron oxides, and the composition of the products was studied. It was shown that the use of a catalytic additive in the course of the thermolysis of coal in water led to an increase in the yield of liquid and gaseous hydrocarbons; in this case, the fraction of maltenes in liquid products increased, and the concentrations of hydrogen and carbon oxides in gaseous products increased significantly.

The thermal stability of resins and asphaltenes of naphthenic and methane heavy oils was studied by thermogravimetry. Based on the data of physicochemical methods of analysis, it was shown that the resins and asphaltenes of the test oils had significant differences in molecular weight, elemental composition, and distribution of carbon atoms in structural fragments. Thermogravimetric analysis was performed by heating the samples from 25 to 650°С at a rate of 10 K/min in an atmosphere of argon. It was shown that the maximum rate of weight loss of naphthenic oil resins and asphaltenes occurred at lower temperatures, as compared to similar components of methane oil. The thermal stability of resins and asphaltenes depended on the composition and structural organization of these components due to their formation from oil dispersed systems of various chemical types. It was established that the thermal stability of resins and asphaltenes of methane oil was higher than the thermal stability of similar components of naphthenic oil.

Dynamic thermogravimetry was used to study the thermal degradation of the oil residue of Usinskaya oil and its saturated, aromatic, resin, and asphaltene (SARA) fractions in the presence of sunflower oil. Thermolysis experiments were carried out in an atmosphere of pure argon. Based on the data of thermogravimetric analysis, the activation energies of the thermal degradation of the oil residue, resins, asphaltenes, saturated and aromatic hydrocarbons, and their mixtures with sunflower oil were calculated in the temperature range of a maximum weight loss rate. It was shown that the addition of 10.0 wt % sunflower oil to the oil residue and its components led to a decrease in the activation energy. This fact indicates that the sunflower oil additive affected the mechanism of thermal degradation of crude oil and its components. The greatest change in the activation energy was observed for asphaltenes: Δ Е а = 48.4 kJ/mol.

Coke formation process is studied by the example of SARA fractions - saturated (S) and aromatic (A) hydro-carbons, resins (R) and asphaltenes (A) - naphthenic and methane crude oils by means of thermogravimetry. The studied oil samples are characterized as heavy, high-sulphur, high-resin and contain large amounts of asphaltenes. They differ from each other in the content of resins, asphaltenes, sulphur, and in the yields of fractions with the initial boiling point (IBP)-360 degrees C. Thermogravimetric analysis was carried out heating the samples from 25 to 650 degrees C at a rate of 10 degrees C/min in argon. It is demonstrated that the yield of coke-like condensation products (coke) depends on the composition and structure of SARA fractions. During thermal analysis, the yield of coke is lower from the fractions of saturated and aromatic hydrocarbons and resins of naphthenic oil than from similar frac-tions of methane oil. The amount of solid products formed during thermal analysis of asphaltenes from naphthen-ic oil is larger than for asphaltenes of methane oil. Experimental and calculation data on coke yield from thermal analysis of model mixtures are presented. It is determined that coke formation during thermal analysis of model mixtures is not a direct function of the additive contribution from each of the components of the mixture.

Selective chemical decomposition, IR spectroscopy, and high-resolution mass spectrometry were used to study the composition of structural fragments linked through sulfur bridges in the asphaltene components of heavy fuel oil as well as the products of its thermal and thermocatalytic cracking. Pyrolysis in the presence of initiators derived from fly ash ferrospheres leads to more extensive changes in the structure of the asphaltene components.

The paper presents the results of the electron beam irradiation of resin-asphalt components of oil from the Usinskoye and asphaltenes from the Nurlatskoye oilfields. The results obtained show that no cleavages of chemical bonds occur in the resin-asphalt components of oil under exposure of oil to an electron beam of low intensity (90 keV). In this case, dissociation of complex structural units (CSU) in an atmosphere of propane-butane and air or an association of aromatic hydrocarbons, resins, and asphaltenes in CSU in a hydrogen atmosphere occurs. The exposure of the asphaltenes of the oil from the Nurlatskoye oilfield to an electron beam results in an insignificant destruction of CSU in reducing and neutral atmospheres.

The thermal conversion of the oil residue of Usinsk oil in the presence of sunflower oil additives is investigated. It is shown that the addition of sunflower oil affects the amount of the resulted thermal cracking products.

Using the methods of selective chemical destruction, IR spectroscopy and chromatography - mass spectrometry, a comparative study of the composition of structural fragments connected through sulfide bridges in the molecules of asphaltene components of heavy oil fuel oil and products of its thermal and thermocatalytic cracking was carried out. It is shown that the effect of temperature in the presence of initiating additives based on ferrospheres of energy ash leads to deeper changes in the structure of asphaltene components.

A comparative study of the structural characteristics of resins isolated from fuel oil and highly resinous heavy oil from the Usinskoye field and the composition of fragments bound in resin molecules through ether and sulfide bridges has been carried out. It has been shown that the molecular mass of the resins decreased as a result of conversion. This was due to a decrease in the number of building blocks in their mean molecules. The increase in the number of naphthenic rings in the naphthenoaromatic system of such blocks was due to the occurrence of cyclization reactions of hydrocarbon radicals formed during the cleavage of labile C-C, C-S, or C-O bonds. It was found out that the main contribution to the structure of the resin components of oil was made by fragments connected mainly through the functional group of esters.

The thermolysis of asphaltenes from the vacuum residue of heavy oil was carried out without water and in the presence of supercritical water (SCW) at 450°C. The composition of asphaltene conversion products was studied. It was established that the yield of solid products decreased and the yield of maltenes increased when the process was carried out in SCW. The resins, residual asphaltenes, and solid products (products insoluble in chloroform) isolated from the thermolysis products were characterized by IR spectrometry.

Hematite nanoparticles (23-150 nm) were obtained and dispersed in a hydrocarbon medium. The introduction of hematite nanoparticles at a concentration of 0.02 to 0.30 mass % into the oil residue during thermolysis allows increasing the yield of gasoline and reducing the yield of resins. The role of hematite is explained by its ability to selectively sorb resins and asphaltenes on its surface.

The possibility of biochemical oxidation of polyaromatic hydrocarbon mixtures (PAHs) by the mixed culture of hydrocarbon-oxidizing microorganisms (HOM) in a liquid medium and soil was investigated. The mixed HOM culture was represented by Pseudomonas stutzeri, Pseudomonas putida, Bacillus cereus, and Arthrobacter globiformis genera. It was shown that during HOM cultivation of the microorganisms under study in the liquid medium their number increases from 0.25·104 to 11·108 CFU/ml, which is accompanied by an increase in their oxygenase activity. All PAHs identified were subjected to oxidation from 11.3 to 100%. The results of experiments on biodegradation of PAHs under natural conditions have shown that for 60 days the total utilization of oil products in soils was on the average 65% of the initial contamination. This suggests the prospects for the use of the mixed HOM culture under study for effective biodegradation of PAHs polluting soil and waste waters.

The thermal transformations of components of the residue (boiling point above 350°C) of Zuunbayan heavy, high-wax oil (Mongolia) in the presence of cogeneration plant flyash ferrospheres and sunflower oil have been studied. The use of the additives made it possible to obtain additional amounts of distillate fractions (IBP–360°C). The physicochemical characteristics and composition of the products have been determined. The structural-group characteristics of the resin–asphaltene components of the feed petroleum residue and the products of its thermal conversion in the presence of sunflower oil and flyash ferrospheres have been compared. The presence of sunflower oil and ferrospheres leads to a decrease in the molecular weight of the resins and asphaltenes isolated from thermolysis products. The number of naphthenic and paraffinic carbon atoms in resin and asphaltene molecules decreases, and the proportion of aromatic atoms markedly increases.

Thermal transformations of resins and asphaltenes of the oil residue at a cracking temperature of 435°C in the presence of sunflower oil are investigated. The object of the study was the residue of atmospheric-vacuum distillation of a heavy oil from the Zuunbayan oilfield. The structural group parameters of the molecules of resins and asphaltenes of initial fuel oil and thermolysis products are determined on the basis of data of elemental composition, molecular mass, and 1H NMR spectra.

The physicochemical and structural-group characteristics of fuel oils of heavy and light oils are studied. Using the methods of elemental, structural-group analyses, and IR spectroscopy, similarities and differences in their elemental and structural-group composition and the composition of fragments containing heterofunctions are revealed. It is found out that asphaltenes of the fuel oil of heavy oil differ from those of the fuel oil of light oil in a higher molecular mass, which is due to the larger sizes of mean macromolecules. The large sizes of mean macromolecules are associated with a higher number of less cyclic structural blocks consisting predominantly from aromatic rings. A feature of such blocks is also the presence of longer and weakly branched paraffin chains.

The liquefaction of sapropel in the East Siberian region using ethanol under supercritical conditions (260 degrees C, 18 MPa) was studied. The influence of the hydrogen atmosphere and the CoMo/Al2O3 catalyst on the yield and composition of liquid products was established. The presence of a reactive hydrogen atmosphere and a catalyst increased the conversion of organic mass of sapropel (a) from 41.1 to 75.9 wt.%. Gas chromatographic-mass spectrometry, FT-IR, and NMR spectroscopy methods have shown that the bulk of liquid liquefaction products are esters (30.1-46.6 rel.%), alkyl derivatives of phenol (9.5-21.6 rel.%), and nitrogen-containing compounds (12.9-18.9 rel.%). The addition of hydrogen and a catalyst reduces the content of heteroatomic compounds in liquid products and increases the hydrogen content from 7.26 to 8.86 wt.%. The component composition of liquid products of liquefaction in supercritical ethanol was studied. It was shown that the introduction of a catalyst and hydrogen increases the yield of oils in the maltene fraction by 1.5 times. Structural-group analysis of liquid products showed that the average molecule is characterized by a low molecular weight MW = 200 amu. and contains 11 carbon atoms. The average molecule contains 1 aromatic ring with alkyl substituents and 2 oxygen atoms. The sulfur content is low, about 3 atoms per 100 average molecules.