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No 2-3 (2023)
Articles
3-4
Application of Cryogels to the Production of Fuel Briquettes from Finely Dispersed Carbon-Containing Wastes
Abstract
Methods for producing fuel briquettes with various finely dispersed fillers of natural and industrial origin, which are capable of oxidation (combustion) reactions, are described. It was established that elastic polymeric bodies, into which finely dispersed fillers of a hydrocarbon nature were preliminarily introduced, were formed after a freeze–thaw cycle of the aqueous solutions of polyvinyl alcohol. Samples of fuel briquettes with a calorific value of 14.2 to 28.8 MJ/kg and a compressive strength of 2.14 to 2.9 MP were obtained for the associated utilization of industrial waste.
5-10
Influence of the Conditions of Mechanical Processing of Oxidized Coal on the Properties of Humic Acids
Abstract
The results of a study of the effect of mechanical energy on the properties of humic acids in the course of mechanical processing of oxidized coal in a planetary mill are presented. It is shown that, upon the mechanical action on coal in the presence of alkaline and oxidizing alkaline reagents in a planetary-type mill with steel balls used as grinding bodies, the yield of humic acids increased by 25–33%; the molecular weight decreased and the concentration of functional groups increased in comparison with those of humic acids obtained by mechanical processing with ceramic balls. A change in the density of balls affects the mechanics of their motion and the amount of energy during the fall.
11-15
Thermolysis of Brown Coal in Water in the Presence of a Catalytic Additive Based on Iron Oxides
Abstract
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.
16-19
Influence of Heat Treatment Conditions on the Composition of Cracking Products of Oil Shale from the Kashpir Deposit
Abstract
The cracking of oil shale from the Kashpir deposit was studied at various temperatures (425, 450, and 475°C) and process durations (40, 60, 80, and 100 min.). It was shown that the highest yields of liquid products and oils in their composition were achieved at a cracking temperature of 450°C and a duration of 100 min. An increase in the temperature and duration of cracking led to an increase in the concentration of С1–С5 hydrocarbons in the gaseous products by a factor of 2–5. Oils isolated from the liquid products of oil shale cracking consisted of 30–45% polycyclic aromatic hydrocarbons. It was established that an increase in the temperature and duration of cracking led to an increase in the concentration of IBP–360°C fractions in the composition of liquid products.
20-25
Composition of the Organic Compounds of Different Peat Types from the Southern Taiga Subzone of Western Siberia
Abstract
Acyclic (n-alkanes, n-alkan-2-ones, fatty acids, methyl esters of fatty acids, n-aldehydes, squalene, phyton, and phytol isomers) and cyclic (series of di- and triterpenoids, steroids, and tocopherols, phytonadione, and dihydroactinidiolide) organic compounds, many of which are biologically active, in peat samples raised bogs and fens of the southern taiga subzone of Western Siberia were studied using gas chromatography–mass spectrometry. Acyclic structures, among which n-alkan-2-ones were predominant, dominated in sedge and sedge-hypnum peat in contrast to Sphagnum peat, in which n-alkanes predominated. The distribution of pentacyclic triterpenoids, n-alkanes, n-alkan-2-ones, and methyl esters of fatty acids was largely determined by the botanical composition of peat.
26-34
Composition and Structure of the Asphaltene Components of Bituminous Oils
Abstract
It was shown that the averaged asphaltene molecules of bituminous oils include no more than four structural blocks, the skeletons of which differ in the numbers of aromatic and naphthenic rings and the numbers of carbon atoms in alkyl substituents. The crystalline part of the macromolecules of the test asphaltenes had a layered structure. In terms of the number of layers of a packed structure, the thickness and the average diameter of its packing, and the number of aromatic rings in a layer, the test asphaltenes differed insignificantly.
35-40
Nitrogen-Containing Bases of Bituminous Oils
Abstract
Structural group analysis and gas chromatography–mass spectrometry were used to characterize high- and low-molecular-weight nitrogen-containing bases of bituminous oils from various oil and gas provinces of Russia. It was found that the high-molecular-weight bases were similar in their structural organization: their averaged molecules were almost not different in the numbers of structural blocks and aromatic and naphthenic rings contained in them, and the numbers of carbon atoms in paraffin fragments. It was shown that the low-molecular-weight bases of all oils contained similar sets of alkyl-substituted quinolines, benzoquinolines, azapyrenes, and thiopheno- and benzothiophenoquinolines.
41-46
Composition and Structure of the Oil Sediments of Resinous Oil
Abstract
The study of the distribution of sediment formed from test oil on the sediment-forming surface at different temperature gradients was typical for resinous oils: the amount of oil sediment increased with decreasing oil temperature, and its maximum corresponded to temperatures closest to the pour point of oil. The properties and structure of oil sediments, which differed in sampling sites and methods, were greatly influenced by the thermodynamic conditions of sedimentation. In sediments taken directly from a well and formed in dynamic mode at higher temperatures for a short time period, the asphaltene content was lower than that in oil sediments from a receiving tank. In samples taken at the surface and formed at low temperatures for a longer period, the amount of paraffinic hydrocarbons was significantly higher than that in the sediments from the well.
47-53
Changes in the Composition of Heavy Oil and the Structure of Asphaltenes upon Treatment with Isopropyl Alcohol
Abstract
The interactions of the components of heavy oil from the Zyuzeevskoye field (Republic of Tatarstan) and isopropyl alcohol (IPA) at temperatures of 25, 65, and 100°C were studied. It was established that the temperature regime affected the density, composition, and structural group characteristics of the products of interactions between the oil and IPA. The density of the resulting products increased by 4 wt % (from 0.885 to 0.924 g/cm3) as the process temperature was increased to 100°C, and the concentration of resin–asphaltene substances also increased by 4 wt % in this case. It was shown using IR spectroscopy that the tentative concentration of paraffin fragments in the structure of asphaltenes increased significantly when the oil was treated with isopropanol at temperatures of 65–100°C, and the branching factor increased by a factor of 3, as compared to that of the initial asphaltenes. The observed changes were due to the incorporation of isopropyl fragments into the structure of asphaltene molecules upon the processing of heavy oil with IPA.
54-58
Influence of Acid Reagents on Oil Sediment Formation
Abstract
The formation of oil sediment in highly paraffinic oil in the presence of carboxylic and naphthenic acids was studied. The influence of the concentration and composition of acids on the process of sediment inhibition and the concentrations of paraffins, resins, and asphaltenes in sediments was demonstrated. In the composition of sediments obtained from oil with the addition of acidic reagents, the amount of light n-alkanes increased and the fraction of higher molecular weight hydrocarbons decreased. The concentrations of aliphatic fragments and carboxyl groups in the resins of sediments obtained with the addition of acidic reagents decreased, and the aromaticity coefficient increased. Asphaltenes in the sediment were characterized by a decrease in the concentrations of aromatic structures and carboxyl groups.
59-64
Effect of Ultrasonic Treatment on the Properties of High-Paraffin Low-Resin Oil, Sediments, and Raffinates
Abstract
The effect of ultrasonic treatment on the properties of highly paraffinic oil, its sediments, and raffinates was studied. The oil was processed in an ultrasonic field (field intensity, 18 W/cm2; frequency, 22 kHz; and time, 10 min), and sedimentation was carried out at an ambient temperature of 30°C; the coldfinger temperature was 5°C. The viscosity–temperature parameters of oil were determined using a HAAKE Viscotester iQ rotational viscometer. The microstructure of the sediments was studied using an AXIOLAB.A1 microscope. The concentrations of weak and strong acids in oil, raffinates, and sediments isolated from highly paraffinic oil were determined using a potentiometric titration method.
65-70
Study of the Thermal Stability of Heavy Oil Resins and Asphaltenes by Thermogravimetry
Abstract
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.
71-77
Transformation of Heavy Oil Components in the Process of Initiated Cracking
Abstract
In this work, the effect of butyl bromide on the thermal transformations of heavy oil from the Karmalskoye field (Republic of Tatarstan) in the presence of an initiating additive, n-butyl bromide, was studied. It was shown that the addition of butyl bromide increased the yield of gasoline and diesel fractions due to the destruction of high-molecular-weight components. It was established that almost all bromine from butyl bromide entered the compaction products upon the cracking of heavy oil, and butyl radicals entered the composition of gaseous products. It was noted that the direction of thermal transformations of hydrocarbons changed in the presence of butyl bromide. As compared to the initial oil, the amount of low-molecular-weight alkanes and isoprenoids increased significantly, the concentration of cyclohexanes and cyclopentanes decreased, and tri-, tetra- and pentacyclic saturated hydrocarbons were completely destroyed.
78-85
Influence of In Situ Formed Nickel- and Cobalt-Containing Catalysts on the Mechanism of Conversion of Heavy Oil Asphaltenes
Abstract
The influence of the amount of precursors of cobalt and nickel oxides on the composition and structure of catalytic cracking products of heavy oil from the Zyuzeevskoye field was studied. It was found that an increase in the amount of a loaded precursor led to the destruction of a larger amount of resin–asphaltene components and the yield of an IBP–360°C fraction. It was established that nickel-containing catalysts facilitated the destruction of 66% high-molecular-weight components, and cobalt-containing catalysts contributed to a low yield of by-products. The structural group analysis of initial oil asphaltenes and those formed after thermal and catalytic cracking was studied. A possible mechanism of the reactions was presented based on the experimental data.
86-91
Kinetics of the Thermal Decomposition of Oil Residue and Its SARA Fractions in the Presence of Vegetable Oil
Abstract
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: ΔЕа = 48.4 kJ/mol.
92-98
Changes in the Structure of Asphaltene Molecules in the Process of Initiated Cracking of Tars
Abstract
The results of a study of asphaltenes isolated from the liquid products of tar cracking performed at a temperature of 500°C in the presence of didodecanoyl peroxide are presented. The reactions rate constants of the thermal transformations of asphaltenes in the studied tars were calculated. It was found that the reaction rate of asphaltene condensation into solid compaction products depends not only on the initial asphaltene content of tars but also on the molecular structure. Changes in the structural group parameters of tar asphaltenes in the course of initiated cracking were established. It was shown that the destruction of structural blocks without changes in their number in the molecular composition is a distinctive feature of asphaltene cracking in the presence of didodecanoyl peroxide. Averaged asphaltene molecules became more compact due to the destruction of aliphatic substituents and naphthenic rings, and the fraction of condensed aromatic structures in their composition increased significantly.
99-106