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Solid Fuel Chemistry
Journal Prestige (SJR): 0.227  Number of Followers: 0  Hybrid journal (It can contain Open Access articles)ISSN (Print) 1934-8029 - ISSN (Online) 0361-5219 Published by Springer-Verlag  [2469 journals]
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- Donor Properties of Tetralin and Tetrahydroanthracene in the Hydrogenation
of Polynuclear Aromatic Hydrocarbons in an Inert Gas Atmosphere-
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Abstract: The transition of hydrogen from tetrahydroanthracene to naphthalene and from tetralin to phenanthrene in an inert gas atmosphere in the presence of iron oxide on a carbon support (Fe2O3/С) was demonstrated using a binary system of model polyaromatic compounds as an example. The addition of tetralin to phenanthrene in a ratio of 1 : 1 in the course of hydrogenation increased the degree of conversion by 8.45%.
PubDate: 2022-06-01
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- Physicochemical and Electrophysical Properties of a Composite Material
Based on Carbon Nanofiber Produced from Coal Tar and Nanoiron-
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Abstract: Experiments on the production of a nanocomposite material from coal tar obtained from coal of the Shubarkol deposit and nanoiron by electrospinning on a laboratory setup are presented. The elemental composition was determined, and the surface morphology of the test sample was studied. As a result of energy dispersive X-ray spectroscopy and SEM microscopy, the elemental composition (C, 92.14%; O, 6.16%; Al, 0.30%; Si, 0.26%; Р, 0.07%; S, 0.20%; Cl, 0.40%; and Fe, 0.47%) and the diameter of the carbon nanofiber, which ranged from 94.2 to 800.0 nm, were determined. The results of IR spectroscopy showed an increase in the intensity of peaks in a range of 2920–2850 cm–1 and the appearance of a signal at 2359 cm–1, which was explained by the breaking of several chemical bonds in the sample structure and the formation of a composite with nanoiron. The electrical resistance (R), electrical capacitance (C), and permittivity (ε) of a carbonized sample were determined for the first time in a temperature range of 293–483 K.
PubDate: 2022-06-01
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- Hydrothermal Carbonization of Agricultural Biomass: Characterization of
Hydrochar for Energy Production-
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Abstract: This paper shows the results of hydrothermal carbonization of biomass from seven different crops used as biofuel: wheat straw, soybean straw, corn cob, corn stalk, sunflower stalk, walnut shell, and hazelnut shell. The hydrothermal carbonization process was investigated at 200 and 250°C reaction temperatures, a pressure of 8.0 MPa, and 120 minutes of process duration. The obtained dry hydrochar was characterized. The hydrothermal carbonization process increased carbon and decreased oxygen and, to a lesser extent, hydrogen. Higher heating value of hydrochar increased compared to the feedstock. The hydrothermal carbonization process influenced the increase in the share of ash and bulk density. At lower process temperature, a higher mass yield of hydrochar was obtained. The color of the hydrochar correlated with carbon content; lower process temperatures gave brown lignocellulosic color, and higher temperatures resulted in charcoal black. Depending on the raw material, hydrochar was improved in terms of its basic composition and heating value, and it showed to have the potential to be used in coal dust combustion plants.
PubDate: 2022-06-01
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- Changes in the Properties of Native Low-Metamorphozed Coal in Contact with
Air-
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Abstract: Data on the analysis of the chemical composition and physicochemical properties of native low-metamorphosed coal at the initial moment of its contact with the air are presented. Diffuse reflectance IR spectroscopy, EPR spectroscopy, NMR spectroscopy, gas chromatography, chemical analysis of oxygen-containing groups, and the determination of the specific surface area and wettability of the contacting surface were used to identify changes in the organic matter of coal. The dynamics of changes in the numbers of paramagnetic centers and functional groups showed that the most intense transformations in the surface layer occurred in the first day of coal exposure to air. Next, oxidation at room temperature proceeded in a periodic mode of the accumulation and consumption of radicals and functional O groups. After four days, the process of low-temperature oxidation passed from the accessible outer surface into the diffusion region of the porous space of coal and gradually slowed down.
PubDate: 2022-06-01
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- Influence of the Surface Characteristics of Activated Carbon on the
Adsorption of Herbicides (A Review)-
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Abstract: The influence of activation methods on the surface characteristics of activated carbons (ACs) and the relationships of these characteristics and the parameters of a medium with the efficiency of adsorption of herbicide molecules on ACs are considered. The main factors affecting the adsorption efficiency of ACs with respect to these pollutants are discussed.
PubDate: 2022-06-01
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- Prevention of Slagging in the Gasification of Plant Biomass
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Abstract: The process of gasification of biomasses of plant origin containing the additives of sulfur oil shale was studied. It was shown that the presence of sulfur oil shale in the mixtures decreased and, in some cases (at a high sulfur content of oil shale), prevented the appearance of deposits (slagging) on the equipment walls. It was established that a maximum effect was achieved with the addition of 5% oil shale containing at least 16% sulfur.
PubDate: 2022-06-01
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- Formation of Hydrocarbons of the Adamantane Series from Modern and Ancient
Fossilized Resins (Ambers) of Coniferous Trees-
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Abstract: The thermolysis and thermocatalytic conversion of modern and ancient resins (amber) of coniferous trees were carried out. It was established that protoadamantanes were formed upon the thermolysis of both ancient and young resins of coniferous trees, while C10–C14 adamantanes found in oils were formed upon thermal catalysis. It was found that thermodynamically weakly stable hydrocarbons of the adamantane series were predominantly formed as a result of the isomerization of protoadamantanes present in the resins (both modern and fossil) of coniferous trees; then, these hydrocarbons were isomerized into thermodynamically more stable isomers. The amount of di- and trimethyladamantanes generated in the products of thermocatalysis of modern resins (relative to monomethyladamantanes) was significantly greater, as compared with that of fossil resins.
PubDate: 2022-06-01
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- A Study of the Thermal Decomposition of Wastewater Sludge Using Gas
Chromatography-
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Abstract: The process of the thermal decomposition of the samples of mixed industrial and municipal wastewater sludge was investigated using gas chromatography. The composition of pyrolysis products obtained at temperatures of 200, 250, 300, 400, 500, and 600°C was determined. The groups of organic compounds detected in the pyrolysis products were analyzed. The temperatures of the onset of the release of volatile organic components and the highest heat release were determined.
PubDate: 2022-06-01
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- Electric Arc Synthesis of Biomorphic Titanium Carbide from Wood Sawdust
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Abstract: A method for producing titanium carbide with the use of charcoal, vegetable oil, and titanium dioxide powder as initial reagents is described. A feature of this method is that it is implemented in a hollow cathode direct current arc discharge with the effect of shielding the reaction volume from atmospheric oxygen by gases generated in the arc discharge. The possibility of obtaining a synthesis product consisting of a graphite phase and a cubic phase of titanium carbide is shown. In this case, according to scanning electron microscopy data, microsized objects were identified in the synthesis product, the morphology of which corresponded to the structure of charcoal, and the chemical composition, together with X-ray diffraction data, indicated the presence of a titanium carbide phase.
PubDate: 2022-06-01
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- Influence of an Iron Nitrate Additive on the Joint Cracking of a Mixture
of Fuel Oil and Mechanically Activated Oil Shale-
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Abstract: The cracking of a mixture of fuel oil with mechanically activated oil shale in the presence of iron nitrate as a catalytic additive was studied. It was found that iron oxides formed during cracking as a result of the thermal decomposition of iron nitrate deposited on the surface of oil shale are catalysts. The concentration of gaseous products in the cracking products obtained in the presence of a catalytic additive decreased by a factor of 2. At the same time, the oil content of the liquid products increased in comparison with the composition of cracked products without additives. The catalytic effect of the additive led to an increase in the yield of distillate fractions from 62.1 to 82.8 wt %.
PubDate: 2022-04-01
DOI: 10.3103/S0361521922020069
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- IX International Conference “Production, Preparation, and
Transportation of Oil and Gas”-
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PubDate: 2022-04-01
DOI: 10.3103/S0361521922020124
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- Physical Treatment for the Regulation of the Physicochemical Properties of
a Petrolatum-Based Composition-
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Abstract: The effect of low-frequency acoustic treatment on the viscosity, temperature, and energy parameters and the adhesion properties of a petrolatum-based fat composition, which is used at mining and processing plants of the diamond mining industry, was studied. The field treatment of the fat composition was accompanied by a decrease in the melting point, viscosity, and viscous flow activation energy. At the same time, the composition retained fluidity for 8 h without losing adhesive properties. The level of energy costs for heating the composition was several times lower than that with traditional thermal technology.
PubDate: 2022-04-01
DOI: 10.3103/S0361521922020057
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- Calculation of the Rate Constants of Thermal Cracking and Condensation
Reactions of High-Sulfur Tar Asphaltenes-
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Abstract: The paper presents the results of a comparative analysis of the cracking products of three samples of high-sulfur tars obtained at a temperature of 500°C and different process durations. The reaction rate constants of the thermal transformations of asphaltenes in the test tars were calculated using a kinetic model of the cracking process. It was found that the rate of asphaltene condensation into coke depends not only on the initial concentration of asphaltenes but also on their molecular structure. It was shown that the cracking of saturated fragments of the structural blocks of asphaltene molecules containing large aliphatic substituents led to the accumulation of secondary asphaltenes with a high degree of aromaticity, which had higher reaction rates of condensation into coke.
PubDate: 2022-04-01
DOI: 10.3103/S0361521922020136
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- Effect of Dicumyl Peroxide on Changes in the Molecular Structure of
Asphaltenes in the Course of Cracking of High-Sulfur Tars-
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Abstract: The results of a study of asphaltenes isolated from liquid cracking products (at a temperature of 500°C) of high-sulfur tars with an additive of dicumyl peroxide are presented. Characteristic changes in the composition of cracking products depending on the amount of the additive were found. Changes in the structural-group parameters of tar asphaltenes in the course of cracking were determined using 1H NMR-spectroscopic data, elemental composition, and molecular weight measurements. Asphaltene molecules became more condensed, and they were characterized by an increased concentration of aromatic fragments and a decrease in the number of naphthenic units and the length of aliphatic structures.
PubDate: 2022-04-01
DOI: 10.3103/S0361521922020021
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- Structural Transformations of Heavy Oil Asphaltenes from the Zyuzeevskoye
Field upon Thermocatalytic Cracking-
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Abstract: Structural changes of asphaltenes in the course of thermal and catalytic cracking of heavy oil from the Zyuzeevskoye field in the Republic of Tatarstan were studied. Cracking was carried out in a closed-type reactor at 450°С for 80 min. Data on the material balance and material composition of liquid cracking products were obtained. The structural group analysis of asphaltenes from the initial oil and asphaltenes formed after thermal and catalytic cracking was performed. It was shown that the asphaltene molecules of the initial oil have an archipelago type structure. In the course of catalytic cracking, the structure of an average asphaltene molecule transformed into an island type structure. These changes were due to the acceleration of cracking reactions of the feedstock, namely, aromatization and dealkylation, and the breaking of carbon–heteroatom bonds.
PubDate: 2022-04-01
DOI: 10.3103/S0361521922020100
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- Study of the Thermolysis Products of Asphaltenes from the Vacuum Residue
of Usinskoe Oil Produced in Supercritical Water-
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Abstract: 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.
PubDate: 2022-04-01
DOI: 10.3103/S0361521922020070
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- Structural Characteristics of the Resin–Asphaltene Components of the
Organic Matter of Oil Shale from the Dmitrievskoe Deposit and the Liquid
Products of Its Conversion in Supercritical Benzene-
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Abstract: The averaged molecules of asphaltenes and resins of the organic matter of oil shale from the Dmitrievskoe deposit and the liquid products of its conversion in a flow of supercritical benzene were described using structural group analysis based on the joint use of information on the elemental composition, average molecular weights, and 1H NMR-spectrometric data and the results of X-ray diffraction analysis. The results obtained made it possible to expand the understanding of the macromolecular structure of the resin–asphaltene components of oil shale formations and to reveal similarities and differences in their structural organization.
PubDate: 2022-04-01
DOI: 10.3103/S0361521922020033
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- Structural Transformations of Bitumen Asphaltenes after Ultrasonic
Treatment-
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Abstract: The aggregation and sedimentation stability of asphaltene solutions in toluene treated in an ultrasonic field (field intensity, 18 W/cm2; frequency, 22 kHz) for 5 and 10 min was examined. To study the microstructure of the supramolecular formations of asphaltenes and the structural group composition of their averaged molecules, asphaltenes were repeatedly isolated from toluene solutions. It was found that the degree of dispersion of asphaltene aggregates and the aggregation and sedimentation stability increased as a result of ultrasonic treatment for 10 min. In this case, the relative concentration of aliphatic fragments and the numbers of rings in the naphthene–aromatic system, heteroatomic structural fragments, and blocks in the average asphaltene molecule decreased.
PubDate: 2022-04-01
DOI: 10.3103/S0361521922020112
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- Structural Changes in Asphaltenes upon the Cracking of
Asphaltene–Maltene Model Mixtures:-
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Abstract: The influence of the amount of asphaltenes on the yield of distillate fractions in a cracking process and on the structural transformations of asphaltenes under thermal treatment was studied. Model mixtures with asphaltene concentrations of 0, 8, 12, and 16% were the test materials. Cracking was carried out in autoclave reactors at a temperature of 450°C for 2 h. It was found that, in the thermal cracking of mixtures with different amounts of asphaltenes, the yield of distillate fractions IBP-360°C increased with the asphaltene content. A maximum yield of these products was achieved upon the cracking of a model mixture with 8% asphaltenes; it increases by a factor of 1.7, as compared to that in the initial mixture. Secondary asphaltenes decreased in size and became more aromatic with much fewer alkyl substituents.
PubDate: 2022-04-01
DOI: 10.3103/S0361521922020082
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- Changes in the Structural Characteristics and Composition of Oxidized Coal
Because of Mechanochemical Action-
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Abstract: An increase in the concentration of acidic surface groups, the sorption exchange capacity of oxidized coal, and the yield of humic acids by 20–40% due to mechanical action with alkaline and oxidizing alkaline reagents was found. According to the IR-spectroscopic data of coals and the potentiometric titration of acidic groups, a decrease in the concentration of carboxyl groups in aliphatic fragments due to their maximum sorption capacity for metal ions was noted. Humic acids were characterized by a significant increase in the number of oxygen-containing groups and stable polyconjugated heteroaromatic fragments as a result of mechanochemical action.
PubDate: 2022-04-01
DOI: 10.3103/S0361521922020045
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