Home – Home – Jornals – Chemistry for Sustainable Development 2019 number 1

The mechanical treatment of zeolites in mills of various types is a promising modification method not requiring complex instrumentation and not yielding harmful waste water. In addition, dry mixing is the only method that allows introducing nanoscale metal powders into the zeolite structure without changing their properties. The proposed work prepared nickel-containing zeolite samples by the dry mechanical mixing of ZSM-5 zeolite with silicate modulus 40 and nickel powder with an average particle size of 50 nm per 0.5 mass %. They were exposed to mechanical treatment in a vibratory ball mill for 24–120 h. In order to retain properties of Ni nanopowder and avoid nickel oxidation, the resulting catalysts were not calcined. The degree of crystallinity of the initial zeolite and its mechanically treated modifications was determined by IR spectroscopy and X-ray structural analysis. Acidic properties of the catalysts were explored by ammonia thermoprogrammed desorption enabling to determine the distribution of acid sites according to strength, and also their number. Changing the catalytic activity and the selectivity of the initial zeolite and mechanically treated nickel-containing samples was explored in the model reaction of n-hexane transformation. As shown, the preliminary mechanical treatment of Ni/ZSM-5 reduces its crystallinity degree, and also acid sites strength and concentration. The variation of mechanical treatment time may directionally change the catalytic reaction pathway, as established. That allows an increase in the yield of the catalysate with improved environmental characteristics resulting from a decrease in the contents of n-alkanes, aromatic hydrocarbons, and alkenes, and also from a simultaneous increase in the fraction of iso- and cyclo-alkanes therein.

Titanium dioxide nanotubes were synthesised using industrial rutile pigments under the optimum conditions selected. Physicochemical properties and the catalytic activity of the former were examined. As shown, oxidation of sulphur compounds of diesel fraction in the presence of titanium dioxide nanotube-based catalysts allows simple and efficient treatment of oil products.

The paper reports laboratory test results of the MEGA system developed at the Institute of Petroleum Chemistry of the Siberian Branch of the Russian Academy of Sciences. The composite was designed for enhanced oil recovery and restricted water inflow and had two gel-forming components, polymer and inorganic ones based on the aluminum salt – cellulose ether – carbamide – water system. The technology is intended to enhance oil recovery through increasing the coverage of the reservoir at flooding, steam-heat and cyclic steam stimulation and a restricted water flow in a wide temperature range (60–220 °C). As a consequence, the nanostructured “gel-in-gel” system with improved structural-mechanical properties is generated. Owing to gels formed in the reservoir water or steam breakthrough from injection wells into producing wells is restrained and filtration fluid flows in the oil reservoir are redistributed. That leads to a stabilized or reduced water cut of products of surrounding producing or steam-cycle wells and enhanced oil recovery.

The paper deals with the research on the composition of cracking products of the bitumen from the Bayan-Erkhet deposit (Mongolia) upon varying process times, temperatures, and also in the presence of radical-forming additives (styrene, benzoyl peroxide, and di-tert-butyl peroxide). Typical features of changing the material and fractional composition of cracking products were demonstrated depending on conditions. The transformation nature of resinous-asphaltenic components was explored.

The paper deals with the research on the composition of cracking products of the bitumen from the Bayan-Erkhet deposit (Mongolia) upon varying process times, temperatures, and also in the presence of radical-forming additives (styrene, benzoyl peroxide, and di-tert-butyl peroxide). Typical features of changing the material and fractional composition of cracking products were demonstrated depending on conditions. The transformation nature of resinous-asphaltenic components was explored.

Research was carried out on non-oxidative conversion of methane and its mixture with water into gaseous and liquid products in the barrier discharge (BD) plasma. The major products of methane conversion are hydrogen (~60 %) and ethane (~29 %), and also gaseous C3–C4 hydrocarbons (~10 %) and С₅₊ alkanes (~1 %), of mainly isomeric composition. The conversion of methane is 9.5–9.7 % in both cases, which corresponds to the energy consumption for CH4 reforming in the order of 46 eV/molecule. The presence of water on plasma-chemical reactor walls makes conditions for the efficient withdrawal of products from the discharge zone and prevents the formation of a deposit on the surface of the electrodes, which is proven by IR spectroscopy data. The paper deals with the redox mechanism of methane conversion in the BD plasma. As demonstrated, there is reaction initiation resulting from the collision of methane molecules with discharge electrons. Methyl and methylene radicals, and also atomic and molecular hydrogen, are mainly generated as a consequence of dissociation of the electron-excited methane molecule. Reaction products are further formed via the radical mechanism. The kinetics of transformation of the methane-water vapour-gas mixture into BD was modelled using the effective rate constant of the electron-molecular reaction and a simple expression to assess the value of the former. The expression for assessing the effective rate constant links the actual constant of the electron-molecular reaction rate to key parameters of the BD plasma and allows simplification of the simplification procedure of the modelling of the first. The chemical kinetics model for methane conversion involves 74 reactions. The calculation results are in good agreement with experimental data. As demonstrated by the analysis of reaction sensibility coefficients, there is an increase in the molecular mass of products mainly due to processes with methylene radical involvement.

The effect of n-butyl bromide on thermal transformations of maltenes from heavy oil of the Usinskoye oil field (Komi Republic) was explored. The cracking of maltenes was performed at 450 °С for 2 h in the isothermal mode in the presence of the initiating additive, n-butyl bromide. The data for the mass balance of the process and the composition of liquid cracking products were acquired. Variations in the hydrocarbon composition of the cracking products were investigated. As demonstrated, the addition of n-butyl bromide (0.7 mass % of the mass of raw materials) led to a 1.8 times increase in the yield of distillate fractions boiling up to 360 °С compared to cracking without the additive. As determined, along with the profound destruction of resins, oils were exposed to transformation upon the cracking of maltenes with n-butyl bromide due to dealkylation and dehydration reactions.

The paper deals with opportunities of remote probing as a method to assess the environmental condition of hard-to-reach areas. The dynamics of changing the condition of the vegetation cover of anthropogenically disturbed areas of the Tomsk region under conditions of the negative impact of oil recovery was investigated using freely distributed satellite MODIS images of medium spatial resolution. Vegetation cover condition was assessed according to the value of the normalized difference vegetation index (NDVI). Condition dynamics for vegetation cover in the vegetation season was analysed over the 9-year period from 2010 to 2018. The work stepwise stated the processing algorithm of satellite data using geographic information system ArcGis 10.2.2. Analysis was performed for NDVI values of the background territory of the Oglatsky wildlife reserve and five territories of oil and gas fields in the Tomsk region. The latter include Luginets, Olenie, Lomovoye, Katylginsky, and West Katylginsky fields. As determined, the trend of changing index values for all investigated areas is single-type: high and minimum magnitudes in 2016 and 2012, respectively. As demonstrated by the analysis of the dynamics of changing average NDVI values during vegetation, there are improved but significantly reduced NDVI magnitudes in all investigated areas from 2012 to 2016 and 2016 to 2018, respectively.

The paper reports on the process of deposit formation for water-in-oil emulsions of paraffinic and highly paraffinic oils of varying water content. The effect of additives based on polyalkylmethacrylates on the quantity and composition of deposits of water-in-oil emulsions was explored. As shown, the inhibiting ability of K-210 additive was increased upon the deposit formation of water-in-oil emulsions compared to the initial oil. Herewith, the efficiency of its foreign analogue, Flexoil additive, was reduced. As determined, the nature of a change in the composition of paraffinic hydrocarbons in emulsion deposits of anhydrous oil systems was the same in the presence of additives. Therefore there remained the same effect of additives in the presence of water in the oil system.

The content and chemical composition of organic oil-soluble constituents (lipids) of the snow cover, peat and water of the Bakchar bog, which is the typical bog for southern taiga (the northeastern spurs of the Great Vasyugan Mire) were explored by gas chromatography-mass spectrometry. As shown, the composition of lipids in waters is exposed to seasonal fluctuations and formed due to compounds generated in a peat deposit and falling with atmospheric precipitation, and also to components of plants. Lipid content is linked to level dynamics of waters, the quantity of fallen atmospheric precipitation, and air temperature. The amount of lipidic components in waters is maximum in the beginning of spring; their composition is almost identical to peat compounds. When water is diluted with melting snow, lipid content is reduced. Herewith, the fraction of the main groups of lipids: n-alkanes, and n-aldehydes, and also cyclic mono- and sesquiterpenoids present in plants of the early growing season in the snow is increased.  An increase in air temperature and a low amount of atmospheric precipitation lead to an increased fraction of lipids produced by water plants and compounds that are a part of conifer resin (dehydroabietic acid and its derivatives) in water. When the amount of rain precipitation is increased, the diversity of composition and lipid content are reduced in water; C₂₅ and C₂₇ n-alkanes, and also carboxylic acids are prevailing in this case. A reduction of the amount of atmospheric precipitation at the end of summer is accompanied by an increase in the content of triterpenoids, steroids, long-chain esters of carboxylic acid, and tocopherol in water. Furthermore, betulin and its derivatives typical for birch, and also saturated oil hopane derivatives fallen to water resulting from carrying out technical works appear at the survey plot. A month later, in September, human activity products are removed from the waters; the content of biological triterpenoids, and among them, α- and β-amyrin derivatives enriched with red bilberry and cranberry is drastically increased.

The distribution of natural and anthropogenic components, and also compounds of mixed origin in sediments of lakes in Southern Siberia, and also Altai steppes and mountains characterised by a varying degree of mineralisation (between 0 and 300 g/dm3) was explored by gas chromatography-mass spectrometry. The contribution of the major organic matter sources to the composition of bottom sediments was assessed. Specific oil compounds were determined. As determined, there was the formation of the composition of bottom sediments mainly due to compounds of biogenic and mixed origin. Sections with a high content of pollutants, such as petroleum and pyrogenic hydrocarbons, and also isoalkylbenzenes, i.e., likely degradation products of surfactants, were detected.

The paper deals with the solid-phase method for producing bulk two-component sulphide catalysts by the mechanochemical coupling of commercial molybdenum, cobalt, and nickel powders. The research presents physicochemical properties of the catalysts and discusses the activity of the latter in model reactions of dibenzothiophene and 4,6-dimethyldibenzothiophene hydrodesulphurisation including the latter in the presence of carbazole and phenanthrene, and also upon the hydrotreatment of sulphur components in diesel fraction.

The paper substantiates the research results on the composition and structure of resinous-asphaltenic materials of low resin and heavy highly resinous oils by a set of physicochemical research methods (extraction, liquid adsorption chromatography, elemental analysis, cryoscopy in benzene, IR and ¹H NMR spectroscopy, structural group analysis, the selective chemical breakdown of sulphide, ether, and ester bonds, and also by gas chromatography-mass spectrometry). Similarities and differences of the structural-group composition of resins and resin nitrogenous bases were detected. Compositions of moieties bound via ether/ester and sulphide bridges in resin and asphaltene molecules, and also those of compounds adsorbed by occluded asphaltenic species were investigated. As determined, composition and structure peculiarities of resin and asphaltenic molecules were dependent on the chemical nature of the initial oil species.

The paper reports on the research results of the formation process of emulsions in paraffin and highly resinous oil varieties. The effect of the composition of resin-asphaltene components and aqueous phase content in oil on pour point, rheological properties, and the viscous flow activation energy of oil-in-water emulsions was demonstrated. As determined, large resistant globules of water were formed in oil-in-water emulsions where paraffin hydrocarbons, were prevailing; the pour point, viscosity, and the viscous flow activation energy were increased. Emulsions of highly resinous oils were characterised by the formation of structures with small globules of water, high viscosity and the low viscous flow activation energy. The power relationship of the size of water globules in oil-in-water emulsions on the ratio of the content of resin-asphaltene components and paraffin hydrocarbons was determined.

This paper presents the analysis of the physicochemical properties of unconventional scavenger oils of the Siberian part of the Arctic zone of Russia, which is important in view of the current trends in the development of oil and gas industry. These trends are as follows: an increase in the share of hard-to-recover reserves in the structure of the hydrocarbon resource base, complicated by geological and physical characteristics of reservoirs and special anomalous physical and chemical properties, and shift in the geography of hydrocarbon production to the eastern and Arctic regions of the country with severe climatic conditions. An approach to the study of oil properties based on the classification of hard-to-recover oils is proposed. It is illustrated by the example of the analysis of the features of different types of arctic oils difficult-to-recover in Siberia. The analysis is based on the classification of hard-to-recover oils as a result of literature data compilation. Using the world database on the physicochemical properties of oils, an analysis of the distribution of oils with anomalous properties has been conducted, taking into account increased density, viscosity, high content of sulphur, resins, asphaltenes, solid paraffins, vanadium, nickel, and increased or decreased gas saturation, etc. The oil deposits with abnormal occurrence of productive reservoir were found out. The following complicating factors were identified during their development: low-permeable and low-porous reservoirs, reservoirs with abnormally high or low temperature, reservoirs with a burial depth of more than 4500 m, and those occurring in the areas of permafrost distribution, etc. The data on more than 4.200 samples of Arctic oils were analysed, which allowed determining special physicochemical properties of hard-to-recover oils deposited in various oil and gas basins of the Arctic zone, especially of its Siberian part. The results of the investigation can be used to develop new technologies and improve the existing methods of oil production and refining under specific Arctic conditions.

The technical ceramics of the Bronze Age Krotovo culture of the Baraba forest-steppe (the end of the III – the beginning of the II millennium BC) were analysed. Samples of internal and external surfaces of casting molds and crucibles were measured by thermogravimetric analysis. Good and very good quality of firing was identified. Reliable differences in the mass loss were identified between the inner and outer surfaces of the crucibles, which allows determining the type of fire installation (open or closed), the direction of air injection onto the crucible, and the period of use. Other processes occur in a mold. During metal pouring, a large gradient of temperature arises: at the surface of contact with the casting, mold temperature approaches the temperature of the melt. At the outer surface, temperature is equal to the initial level at this moment. However, the time of temperature action is short-term and limited by the period of metal solidification. The difference in the mass loss between the inner and outer surfaces can get accumulated only in the case of a long-term use of the mold, and thus it provides evidence of how many times the mold was used. Determination of the functional differences between technical ceramics, crucibles, and molds can be made on the basis of differences in mass losses for the inner and outer surfaces. The results of thermogravimetric analysis add essential objective data to the solution of the question of the multiple uses of forms and, as a result, the reconstruction of the technology of the ancient bronze casting production in Eurasia.