Home – Home – Jornals – Advanced Search

An opportunity to use Zh, D, and KS coal of the Kuznetsk Basin referred to bituminous coals as raw materials to produce activated carbon was investigated. Formulas of coal/pitch systems were developed using coal-tar pitch as a binder. The optimum coal tar content (5 mass %) in the system was determined. New activated carbons based on coal/pitch systems were produced; parameters of their microporous structure, adsorptive properties, and strength performance were examined.

The paper presents research results on the pore structure and the reactivity of semicoke derived from LF, LFG, G, F, and C coal by low-temperature pyrolysis at 600 °C in the Fisher vessel. It is certified that the development of pore structure upon semi coking depends on the nature of the initial raw materials because when the degree of metamorphism is increased, the specific surface area of semicoke derived therefrom is reduced. As demonstrated by comparative analysis, semicoke derived using coal of a higher degree of metamorphism is characterised by reduced reactivity towards oxygen. The correlation between the temperature of the beginning of mass loss (T₁) and that of maximum mass loss rate (T_max) of oxidative breakdown for the investigated samples of semicoke vs its specific surface area was found. It is stated that T₁ and Tmax indicators are reduced when the specific surface area of semicoke increases.

The paper investigated petrographic characteristics of seam commercial samples of gas coal collected in various Kuznetsk Basin mines. Reflectogram analysis identified petrographic peculiarities that determined coal cokeability during high-temperature coking. According to the results of the additional assessment made for coal physicochemical properties, significant gas coal reserves might be used as valuable raw materials for the coke-chemical industry.

Physicochemical properties of coal dust sampled from the fine filter of the mine degassing plant of the Kuznetsk coal basin were explored. The coal dust sample was thoroughly characterised by scanning electron microscopy and atomic emission spectroscopy; technical analysis was also carried out and granulometric composition was determined. Relationships were found between changing the chemical composition of mineral components of the mineral portion of coal dust and coal particle size relying on the data acquired.

Lately, side products of oil processing and coal liquefaction, i.e., asphaltenes, have been extensively investigated. The data regarding the macromolecular structure and morphological characteristics of asphaltene aggregates were mainly acquired in the area of petrochemical technologies. It is known that the concentration of asphaltenes in solution and the presence of additives of various chemical nature have an effect on the structure of asphaltene associates. The data about the formation of planar asphaltene associates and condensed graphite-like structures are of particular interest. In connection with the optimizing of conditions for anodic mass graphitization, coal tar pitch asphaltenes (β-fraction) were investigated. Coal tars with high contents of β-fraction proved themselves in the best way as efficient binders upon thermal treatment of the anodic mass. The present work investigated structural characteristics of macromolecules of medium-temperature coal tar pitch (CTP) using a set of physicochemical methods. The method of selectively soluble groups was used to isolate β-fraction asphaltenes; toluene and hexane were utilised as selective solvents. In order to form asphaltene films, a 0.01 % solution of asphaltenes in toluene was selected. It was demonstrated that structural fragments of CTP asphaltene molecules contained mainly condensed compounds with a number of rings of 3–7. These species contained C11 alkyl substituents and larger the content of which could not be practically determined. Therefore the structure of CTP asphaltene molecules could be described by the Speight model. The coke residue of CTP asphaltenes is characterised by the presence of crystallites from naphthenoaromatic layers. These structures are comprised of subunits of 7–8 layers, with a size of 20–25 Å, graphite-like; an interlayer distance of 3.42 Å.

Preparation methods of nanostructured composites based on various carbon materials filled with chromium oxides and hydroxides were developed via reduction of potassium dichromate with hydrazine. Materials with different parameters of the porous structure and specific surface, such as microporous Kem10 and mesoporous Carb3, and also carbon nanotubes (non-ozonised CNT-1 and ozonised CNT-2), were used as carbon matrixes. As demonstrated by research on asymmetrical cells of a supercapacitor with working electrodes based on the resulting nanocomposites via a set of electrochemical methods (cyclic voltammetry, chronopotentiometry, and impedansometry), surface decoration of matrixes with chromium oxides and hydroxides leads to an increase in capacitance and a decrease in the inner resistance of supercapacitor cells.

The paper presents the research results of structural-morphological and electrochemical properties of an electrode material for supercapacitors. The material is a porous carbon matrix with embedded mixed cobalt-nickel oxide nanoparticles. A nanostructured composite was produced by thermal decomposition of mixed nickel-cobalt hydroxides on the surface of carbon nanofibres. The composition and dispersion characteristics of the resulting oxide nanoparticles were determined through X-ray structural analysis and small-angle scattering. As demonstrated by the research on electrochemical properties of the synthesized electrode materials through cyclic voltammetry, the electric capacitance of the latter increased proportionally to an increase in the content of nickel cobaltate in the composite. Electrode materials based on nanostructured carbon-nickel cobaltate composite ensured a significant increase in electric capacitance compared to that of the initial carbon matrix.

The paper considers properties of nanostructured composites for supercapacitors electrodes. The materials are based on multi-walled carbon nanotubes obtained by pyrolysis of the propane-butane mixture (CNT-1) and additionally aged in argon atmosphere (CNT-2). The resulting CNT are filled with cobalt and nickel hydroxides nanoparticles deposited on the surface and in channels composing nanotube fibres. The composites were explored through transmission electron microscopy, X-ray diffractometry, X-ray Fluorescence Element Analysis, and Small-Angle X-ray Scattering. Electrochemical properties of the resulting nanocomposites were examined. As shown, both introducing cobalt-nickel hydroxide into the carbon matrix and functionalizing its surface by ozonation facilitates an increase in the electrical capacity of composite electrodes. This is driven by the pseudocapacitance of nickel-cobalt hydroxides generated as a consequence of reversible redox processes with the involvement of oxyhydroxide phases formed upon cell charge-discharge.

The paper presents the results of a voltammetric study of electrodeposition and electrooxidation of nanostructured systems based on iron and platinum with glassy carbon electrodes in various electrolytes. The capabilities of anodic and cyclic voltammetry in the characterization of nanometallic deposits were shown. The conditions for electrochemical synthesis and voltammetric studies of nanostructured electrolytic iron-platinum systems were established.

One of the possible variants of rational processing highly paraffinic gas condensate residues (HPGCR) with the maximum yield of low-sulphur medium-distillate fractions, i.e. hydrocracking in a fixed catalyst bed, was considered. Experiments were carried using a flow through plant. Home-made catalysts, such as KNT-442МNi (hydrorefining catalyst) and KNT-442NiY (hydrocracking catalyst) manufactured at the LLC Ishimbayskiy SKhZK, were used. Process temperature that ensures the maximum yield of diesel fraction was pre-selected. Considering the unique composition of HPGCR, the hydrocracking of initial raw materials, and also 350+ °С and 350–500 °С fractions, was investigated without their pre-preparation. As demonstrated by analysis of diesel fractions of hydrocracking products (180–350 °C), various variants of raw materials, regardless of their fractional composition and recirculation of residues, their key parameters meet the requirements for the commercial diesel fuel of environmental K-5 class. At the same time, regardless of the quality of initial raw materials, the products from variants with the recirculation of residues have somewhat improved characteristics. As demonstrated by analysis results for gasoline fractions (IBP – 180 °C), products have similar characteristics, regardless of the composition of initial raw materials and the residue recirculation mode. These fractions do not require preliminary hydroforming and may be directed to isomerisation and reforming plants. Among the variants considered, the hydrocracking of the initial HPGCR ensuring the maximum yield of diesel fraction and not requiring the preliminary fractionation of initial raw materials and the secondary processing of the primary distillate fractions and the residue is preferable.