Home – Home – Jornals – Chemistry for Sustainable Development 2024 number 2

The fields of pollutant dispersion in the air from three operating flare installations at the territory of the Mamontovskoye field in the Nefteyugansk region of the Khanty-Mansi Autonomous District were modelled on the basis of climatic data and technological parameters of flare installations. The amounts of pollutants entering the atmosphere from associated petroleum gas combustion were calculated: carbon monoxide (CO) - 83 %, nitrogen dioxide (NO₂) - 0.7 %, soot -10 %, methane - 6 %. The vegetation cover was mapped relying on the Sentinel-2 satellite image with the shooting date of June 14, 2021, displaying dispersion fields for СО, NO₂ and soot. The distances from emission source (flare installation) to isolines with CO and soot concentrations equal to 1 MPC_st (5 and 0.15 mg/m³) are 163 and 505 m, respectively (here MPC_st is the maximum permissible concentration for short-term exposure level). Similarly, measured distance to the isoline with NO₂ concentration 0.1 MPC_st concentration (0.02 mg/m³) is 284 m. On average, CO concentration decreases by 1 mg/m³ at a distance of 86 m and becomes equal to 0.2 mg/m³ (0.04 MPC_st) at a distance of about 572 m. The resulting model for CO dispersion does not contradict MERRA-2 satellite data, according to which the concentration of CO in the vicinity of the flare installation was 0.2 mg/m³. The gas chromatographic - mass spectrometric analysis of soil samples and plants collected to the north-east from the flare installation at a distance of 216, 486, 710, 1037 and 1380 m has shown that aliphatic hydrocarbons prevail in the composition of soil organic matter. Their content varies from 50 to 80 % of all identified compounds, with the predominance of high-molecular homologues (C₂₇-C₃₃). The maximum total amount of n -alkanes (75.3 μg/g) was detected in the soil sample taken at a distance of 710 m from the flare installation. In the organic matter of pine needles and blueberry leaves, C₂₇ homologue dominates, and C₂₅, C₂₉, C₃₁ characteristic of terrestrial vegetation are present. In addition, polyaromatic compounds were identified in the soil: anthracene/phenanthrene, fluoranthene and pyrene.

Within the framework of green chemistry principles, the concept of deep eutectic solvents (DES) was used to develop solid commercial forms of oil-displacing compositions. It has been shown that the eutectic composition on the phase diagram of the binary system ammonium salt - carbamide corresponds to DES as the basis of solid commercial forms of oil-displacing composition with the best physicochemical and technological characteristics. The optimal concentrations of solid commercial forms in the working solution of the composition were determined for the ternary DES system ammonium salt - carbamide - water. The results of laboratory studies and field tests of the working solution based on the solid commercial forms of the oil-displacing composition are presented.

Postsynthetic treatment of ZSM-5 zeolite with an aqueous solution of NaOH was carried out, followed by the modification of the treated zeolite with nanosized nickel powder. Nickel powder is introduced into the zeolite by dry mechanical mixing. The textural, acidic and catalytic properties of the original ZSM-5 zeolite and zeolite-based samples after alkaline treatment and modification are studied. The catalytic activity of zeolites has been studied in the process of conversion of straight-run gasoline fraction of oil. Along with determining the characteristics of the target reaction products - high-octane gasolines, an analysis of the resulting gaseous hydrocarbons and carbon compaction products (coke) was carried out. It has been established that alkaline treatment of zeolite and its subsequent mixing with nickel nanopowder leads to a decrease in the total specific surface area and total specific pore volume, a decrease in the concentration of acid sites and an increase in their strength. The enhancement of the combined effect of alkaline treatment and modification with nickel nanopowder on the textural and acidic properties of zeolite catalysts was determined. It has been shown that modification of zeolite catalysts has almost no effect on the composition of gaseous products formed in the conversion of straight-run gasoline fraction of oil. Post-synthetic alkaline treatment of ZSM-5 zeolite significantly reduces its aromatising and cracking activity, resulting in an increased yield of high-octane gasoline with improved environmental characteristics. The introduction of nickel nanopowder into alkali-treated zeolite enhances this trend, although not significantly. On modified zeolites, the amount of carbon compaction products is reduced, which will increase the time of stable operation of the resulting catalysts and improve the conditions for their regeneration.

Resins extracted from heavy high-viscous oil of the Nurlat oilfield were investigated. The composition of fragments bound through sulphide and ether bridges in the molecules of initial resins and the liquid products of their conversion at 450 ^oC under the conditions of laboratory experiment was studied using a set of physicochemical methods (IR spectroscopy, UV spectroscopy, gas chromatography -mass spectrometry, chemical destruction). It is shown that the fragments undergoing destruction are mainly those bound in the structure of the initial sample through the least thermally stable functional groups of esters and aliphatic sulphides. Sulphur- and ether-bound compounds in the structure of both resin samples are represented by n -alkanes, n -alkylcyclopentanes, n -alkylcyclohexanes and hopanes. The presence of nickel porphyrins was established among the sulphur-bound compounds. It is the molecular composition of bound n -alkanes that changes most noticeably during thermolysis. Ether bond cleavage in the molecules of secondary resins leads to the formation of products containing mono- and dibromides of alkyl biphenyls. This fact provides evidence that these aromatic compounds are present in resins in the form of fragments bound with other structural fragments through one and two ether bridges.

The extraction of sulphur-containing compounds of diesel fuel (DF) with ionic liquids (IL) based on imidazole with various substituents (butyl, octyl, nonyl, dodecyl, cetyl) in position 1 of the imidazole ring has been studied; the composition of sulphur-containing compounds and polycyclic aromatic hydrocarbons (PAH) has been determined by gas chromatography - mass spectrometry in the initial and purified diesel fuel. The optimal extraction conditions are determined: temperature 30-35 °C, extraction time 60 min, DF/IL ratio 1.66-2. The most effective extractant for the sulphur-containing compounds of DF is 1-nonyl-3-methylimidazolium bromide, which allows reducing the total sulphur content from 0.369 to 0.143 wt%. Results of the studies of group and individual composition of dibenzothiophene (DBT) and PAH derivatives show that the degree of extraction of DBT derivatives and tricyclic aromatic hydrocarbons is 66-72%. Naphthalene and its homologues are extracted to a lesser extent - 37%. Among DBT homologues, dimethyldibenzothiophene is extracted most completely.

The results of rheological measurements of a low-temperature composition based on inorganic components developed at the Institute of Petroleum Chemistry SB RAS (GALKA ^® ) are presented. The studies were carried out with a Haake Viscotester IQ rheometer using CC25 geometry (oscillation mode at a frequency of 1 Hz) at different temperatures. The amplitude test determined the range of strain and stress amplitude values corresponding to the range of linear viscoelasticity. For a given value of the deformation amplitude from the range of linear viscoelasticity, the dependences of the complex viscosity modulus (|η*|), the elastic modulus (storage modulus, G' ), and the viscosity modulus (loss modulus, G'' ) on time were recorded at a temperature of 38, 30, and 20 ºС. The kinetics of the gel formation process was characterized, the maximum strength of the formed structure was estimated from the maximal elastic modulus, the time of its formation and the starting points of gelation were determined.

A composition characterised by adjustable physicochemical parameters within a broad range has been developed relying on the results of studies of the phase equilibria in the ternary system of deep eutectic solvents (DES) glycerol - carbamide - boric acid. The effect of this composition on oil recovery enhancement is studied, and results obtained in the laboratory studies of the effect of DES-based composition on the filtration characteristics of a heterogeneous formation in the carbonate reservoir of the Usinsk field are presented. The efficiency of the composition for oilfields at the early and late stages of development has been assessed by physical modelling. The treatment of a model of a heterogeneous reservoir with the composition is determined to cause a substantial increase in oil displacement coefficient at either low or high temperatures due to equalisation of filtration flows, an increase in reservoir coverage, and restoration of initial permeability. Investigation of the composition and properties of heavy high-viscosity oil before and after treatment with the composition shows that the application of DES-based acid composition does not affect the qualitative composition of oil. The use of the composition leads mainly to redistribution of the content of low- and high-molecular structures: predominantly light occluded hydrocarbons are displaced, while heavy oil components are adsorbed on the reservoir.

Laboratory modelling of oil pollution of water bodies was carried out using the diesel fuel - water - mineral phase system. The content and composition of organic compounds in each of the parts making up the system were studied by gas chromatography - mass spectrometry. The direction of changes in the composition of n -alkanes, polycyclic aromatic and naphthenic hydrocarbons, cyclohexanes, alkylbenzenes and trimethylalkylbenzenes present in diesel fuel during the transition from diesel fuel to the aqueous and mineral phases has been revealed.

The products of oxidative destruction of asphaltenes of heavy Paleozoic oils from the Ashalcha and Nurlat oilfields differing in the age of host sediments have been studied. It is shown that oxidation of the asphaltenes of both oils by hydrogen peroxide in the presence of acetic acid results in the release of occluded compounds. The compounds identified in their composition include n -alkanes, steranes, hopanes and methyl esters of n -alkane acids. A peculiarity of the asphaltenes of Nurlat oil occurring in the Devonian sediments is the presence of n -alkenes in the composition of occluded compounds. The presence of occluded compounds in the structure of asphaltenes is confirmed by the results of X-ray diffraction.

The ecological state of hard-to-reach oil-producing territories of West Siberia has been studied. Results of the analysis of enhanced vegetation index (EVI) dynamics are presented in order to assess the state of vegetation cover over the territories of hydrocarbon fields of in the Yamal-Nenets Autonomous District using moderate resolution imaging spectroradiometer (MODIS) satellite data. The average EVI values of vegetation over oilfield areas were calculated for full growing seasons from May 25 to September 20, 2013-2022. It has been determined that, on average, EVI values for the entire growing season in 2022 became higher by more than 20 % compared to the data in 2013. The trend to an increase in EVI in the final growing season over the 10-year period under study was identified.

The dynamics of the composition of biomolecules in the leaves of Caragana arborescens and Sorbus aucuparia shrubs, typical of the South taiga natural climatic zone, was studied by gas chromatography - mass spectrometry in the process of post-pyrogenic restoration at the territory near the Golovina village, the Tomsk Region, 3 months, 1 year and 2 years after the fire event. Acyclic organic compounds have been identified: n -alkanes, fatty acids, n -alkane-2-ones, aldehydes, n -alkanols. The long-chain saturated alcohol 10-nonacosanol was found in the leaves of Sorbus aucuparia . Aliphatic diterpenoids phytone and the isomers of phytol, triterpene squalene, as well as naphthenoaromatic compounds vitamin E (tocopherol) and vitamin K1 (phytanodione) were detected among isoprenoid structures in the leaves of S. aucuparia , increased phytol and fatty acid levels are observed in the leaves of S. aucuparia 3 months and 1 year after the fire event, and then the concentrations of these compounds decrease to background values after 2 years. Squalene content in the leaves of S. aucuparia , which decreased as a result of the fire event, increased sharply the following year, and after 2 years, it still remained at a level significantly higher than the background. The fire had the greatest impact on the long-chain alcohol 10-nonacosanol, which was detected in large amounts in the leaves of S. aucuparia . As a result of the fire, there is a drop in its content to trace amounts, followed by a slight increase the following year and an abrupt increase up to background values after 2 years. During the two-year-long post-pyrogenic restoration, changes in the molecular mass distribution of acyclic compounds are observed. The leaves of S. aucuparia, sampled 3 months and the following year after the fire, exhibited a shift from higher molecular homologues to less higher molecular n- alkanes and n- aldehydes in comparison with the leaves from background sites, while the corresponding shift observed in C. arborescens related to n- alkane-2-ones. The distribution of acyclic compounds in the post-pyrogenic area approaches the background level 2 years after the fire.

The combined oxidation of gaseous (propane, butane) and liquid (heptane, octane, nonane and decane) alkanes in a barrier discharge plasma in oxygen has been studied. Oxidation process involves simultaneous conversion of gaseous and liquid hydrocarbons. Various C₁-C₄ hydrocarbon gases and mainly oxygenated compounds corresponding to hydroxyl and carbonyl compounds with the same number of carbon atoms in molecules as in the initial alkanes were detected among reaction products. At the stage of chemical reaction initiation in a barrier discharge, the electrons in the discharge interact with all the molecules of the initial mixture to form atomic oxygen and various hydrocarbon radicals. Their subsequent transformation leads to the formation of peroxide radicals of the corresponding alkanes, and their disproportionation leads to the formation of hydroxyl and carbonyl compounds. The mechanism of gaseous alkane oxidation is generally comparable to the mechanism of liquid hydrocarbon oxidation in a barrier discharge, and the key role in the mechanism of alkane co-oxidation is played by the interaction of atomic oxygen with a gaseous or liquid alkane. A probable mechanism for the combined oxidation of gaseous and liquid alkanes in a barrier discharge is proposed on the basis of experimental and literature data, and a simple equation is deduced, linking the rates of atomic oxygen interaction with alkane molecules to hydrocarbon concentrations in the gas phase of the discharge gas in the reactor. Applying the obtained equation, it is possible to estimate the direction of the oxidation of gaseous and liquid alkane mixtures and to involve the experimental data in calculating yet unknown rate constants of atomic oxygen interaction with alkane molecules. The results obtained make it possible to optimise the experimental conditions for the oxidation of gaseous and liquid alkane mixtures with the predominant oxidation of a gaseous alkane. These data will be useful in developing effective methods for the direct processing of a broad fraction of light hydrocarbons.

An approach including preliminary oxidation of vacuum gas oil, chromatographic separation of oxidation products, and thermal treatment is considered. Analysis of the products formed in the cracking of polar and non-polar components of vacuum gas oil oxidised with a mixture of hydrogen peroxide and formic acid is described. It has been established that heat treatment of non-polar components allows obtaining up to 85 wt% distillate fractions boiling up to 360 °C, with sulphur content less than 0.3 wt%. The heat treatment of polar components leads to the formation of distillate fractions at a level of about 50 wt%, and sulphur removal reaches 50 %. It has been shown that the cracking temperature of polar oxidation products determines the route of sulphur removal: at a temperature of 450 °C, sulphur-containing fragments are accumulated in coke, while at 500 °C they are predominantly subjected to destruction with the formation of gas components. It has been determined that gaseous products formed in the heat treatment of both polar and non-polar components of oxidised vacuum gas oil mainly consist of saturated hydrocarbons of the C₁-C₃ series and carbon dioxide. The advantage of separate cracking of polar and non-polar components is elimination of undesired effect on the products formed in thermal decomposition of these components on the route of reactions proceeding in the system. The products obtained in this way are characterized by higher quality. In addition, variation of cracking conditions for separate components of oxidized vacuum gas oil makes it possible to regulate the depth of components destruction and, accordingly, the material balance of the process as a whole.

Zeolites of the structural type ZSM-5 were synthesized using a template, which was pentaerythritol (PER), carbamide (CA), or a deep eutectic solvent (DES) - a binary mixture of PER and CA. It is determined by IR spectroscopy and X-ray diffraction analysis that the nature of the templates used in the synthesis of zeolites affects the phase purity and the degree of crystallinity of the obtained samples. The textural and acidic properties of zeolites and Mo-containing catalysts prepared from them by dry mechanical mixing with nanoscale molybdenum powder have been studied. It is shown that the textural properties of zeolites depend on the template nature. The use of CA promoted obtaining the zeolite with maximal specific surface area and pore volume. The strength of the acid centres of unmodified samples, depending on the structure-forming additive, decreases in the series: DES > CA > PER, and the concentration of acid centers of both types, on the contrary, decreases for zeolites in the series: PER > CA > DES. The catalytic activity of synthesized zeolites has been studied in the processes of non-oxidative methane conversion and refining of the straight-run gasoline fraction of oil. The dependence of the activity and stability of samples on their physicochemical properties caused by the template nature is determined. It has been shown that zeolite synthesized using DES and the 4.0%Mo/ZSM-5 catalyst obtained on its basis exhibit higher activity and stability in the processes of non-oxidative methane conversion into aromatic hydrocarbons and in upgrading the straight-run gasoline fraction of oil, in comparison with zeolite-based catalysts obtained using PER or CA.

The methods for producing cryogels and hydrogels from viscous aqueous solutions of polyvinyl alcohol (PVA) and their rheological properties are considered. Freezing an aqueous solution of polyvinyl alcohol, its exposure to negative temperature and subsequent thawing at a positive temperature lead to the formation of elastic cryogels. Chemical cross-linking of individual PVA molecules into spatial networks is accompanied by the transformation of aqueous solutions into hydrogels. Sodium tetraborate and glyoxal were used to structurise the polymer solutions. It has been determined that the interaction of these reagents with the functional groups of the polymer causes an increase in the viscosity of three-component systems “PVA - glyoxal - water” and “PVA - sodium tetraborate - water” with time. The kinetics of gel formation in the products of chemical reactions was investigated at different concentrations. It is shown that the viscosity of the studied systems increases with an increase in the concentrations of low-molecular reagents in both cases (PVA - glyoxal and PVA - sodium tetraborate). Hydrogels formed at a positive temperature were subjected to additional freezing-thawing cycle, cryogels were obtained, and their rheological properties were studied. The elastic properties of cryogels were determined to be more clearly pronounced than those of hydrogels. Hydrogels can be used as instantaneous gel-forming systems to protect from dangerous chemicals and to make waterproof barriers in hydraulic structures, as the elastic properties are enhanced after cryogenic exposure.

Using information from the database of the Institute of Petroleum Chemistry SB RAS and the methods of statistical and spatial analysis of geographical information systems, we evaluated the data on oil occurrence conditions in the Bazhenov, Domanik and Kuonamka Formations of the oil and gas bearing territories of Russia, the development of which will allow discovering the new sources of increased oil production. The digital maps of the arrangement of hydrocarbon fields in the Bazhenov, Domanik and Kuonamka sediments over the territories of the Volga-Ural, Timan-Pechora and Lena-Tunguska oil and gas bearing basins are presented. The distribution of oils from these deposits over the depth of occurrence in each basin is shown. The lithological features of reservoir rocks are established. The average values of reservoir parameters characterising the filtration and capacitance properties of the pools in these sediments are determined. To analyse the conditions of Bazhenov oil occurrence, a batch of 2833 oil samples from 127 fields of the West Siberian basin was used, for Domanik oil - 407 samples from 195 fields of the Volga-Ural and Timan-Pechora basins, and for Kuonamka oil - 117 samples from 28 fields of the Lena-Tunguska basin. A comparative analysis of the geological and physical characteristics producing a direct impact on the development regime and the effectiveness of technologies used to extract these hard-to-recover oils was carried out: permeability and porosity of rocks, reservoir temperature and pressure. It is shown that the Domanik and Kuonamka sediments are the closest in characteristics to the reservoirs of the developed American shale oil fields, which indicates the possibility for effective application of the positive experience of the United States for Russian oilfields. The results of the study can be used in the development of new and improvement of existing methods and technologies for the extraction and processing of hard-to-recover oils from the studied sediments.

Biogeochemical transformations of sulphur in the saline lakes of southeastern Transbaikalia have been studied. Quantitative measurements show that hydrogen sulphide is present in the water and bottom sediments of most of the lakes studied. In addition to hydrogen sulphide, the presence of sulphate, thiosulphate, and elemental sulphur was detected in the water column, while sulphate and elemental sulphur were found in the bottom sediments. It was established that elemental sulphur exists in the lakes primarily in the form of suspension and colloids, as well as polysulphidic sulphur, the amount of which increases with increasing water pH. It is concluded from the isotopic ratios of sulphur for sulphate, hydrosulphide ions, and elemental sulphur that sulphur in the studied natural systems is controlled by biological and geochemical processes. One of the processes controlling the behaviour of sulphate ions in the lakes is sulphate reduction, which leads to the enrichment of sulphate sulphur and depletion of sulphur in hydrogen sulphide with the ³⁴S isotope. It is shown that oxidation of reduced sulphur in the lakes proceeds with the participation of oxygen, iron, manganese, as well as various bacteria. The presence of an additional source of sulphur and/or absence of sulphur reduction causes ³²S accumulation in sulphate ions. It is determined that the loss of sulphate ions due to their bacterial reduction in bottom sediments is most pronounced in the chloride and soda lakes of the I and III subtypes. In the sulphate and soda lakes of the II subtype, an increase in the amount of sulphate ions was detected.

The discharge of untreated or insufficiently treated sewage into water bodies leads to their pollution, contributing to the emergence and spread of viruses and bacteria that have a negative impact on the ecosystem. One of the indicators of water contamination by pathogenic microorganisms is ammonium ions. The sorption method based on industrial waste as sorbent precursors has become widespread for treating wastewater from ammonium ions. The article presents the results of studies of a calcined sorbent based on ash-and-slag wastes from thermal power engineering plants for the treatment of real wastewater, discharged into the Kuban river within the city of Krasnodar, to remove ammonium ions (NH₄⁺ concentration 21 mg/dm³). The effect of sorption time (10, 30, 60, 90, 150, and 180 min) and sorbent dose (0.5, 1, 2, 3, and 5 g) on treatment efficiency is investigated. The experimental data are processed on the basis of kinetic equations. It is shown that the equation of the pseudo-first-order (Lagergren) provides the best description of experimental data on sorption in comparison with the pseudo-second-order equation (Ho and McKay) and the Elovich equation. It has been established that internal diffusion adsorption is the limiting stage. Treatment efficiency was 72.8 % at a sorbent dose of 5 g for solution volume 50 cm³ and sorption time 180 min. It is shown that the sorbent dose affects the time within which the phase equilibrium between the solution and calcined sorbent is established. The larger is sorbent dose, the larger number of adsorption centres are occupied by ammonium ions per unit time, so, for the fixed ammonium ion concentration in initial solution, shorter sorption time will be necessary to achieve equilibrium. For real wastewater, the time necessary for equilibrium to be achieved exceeds the value determined experimentally with the model mixtures using small sorbent doses. Reasonability of the application of calcined sorbent for treatment of real wastewater is confirmed.