Том 50, № 3 (2016)

It was shown that products or wastes (the primary concentrates of potentially valuable elements (PVEs)) suitable as source materials for the manufacture of commercial PVE compounds or their industrial concentrates can be obtained upon the processing of coal, oil shale, or peat as fuel for combustion or a source material for coking. It was proposed to classify solid fossil fuels containing PVEs with the following two groups: the first group, those suitable for the priority use in the production of primary PVE concentrates and the second group, those promising for the production of primary PVE concentrates after performing appropriate technical and economic calculations. The type of the initial solid fossil fuel or its processing product; the PVE content of the initial solid fossil fuel; the characteristics of PVE distributions in the products of its enrichment, coking, combustion, gasification, and hydrogenation; and the chemical species of ash and slag residues upon combustion (gasification) were chosen as classification parameters, which were designated using numerical or alphanumeric codes.

The results of a study of carbon materials from rice husk, lignin, and cellulose subjected to different activation processes performed by the BET method and X-ray diffraction analysis are reported. The specific surface areas and total pore volumes and the X-ray diffraction compositions and characteristics of the carbon structures of the test samples were determined. It was shown that the treatment of carbonized plant raw materials with direct steam and sodium hydroxide causes the development of a surface and an increase in the degree of order of a carbon structure, whereas the high-temperature treatment (above 1000°С) leads to a decrease in the total pore volume and the specific surface area upon reaching a maximum degree of graphitization in the carbon structure.

The ignition of the drops of coal–water fuel (CWF) in a high-temperature gas (air) flow was experimentally studied. The conditions and fundamental characteristics of the ignition (ignition delay times) were found. The effects of a number of factors (drop sizes and ambient temperatures) on the conditions of ignition were examined. Based on the results of experiments, a physical model was formulated for the processes of thermal preparation and ignition of CWF drops. The experimental delay times of the ignition of CWFs were compared with the theoretical values (obtained with the use of a previously developed mathematical model).

Experiments on the air gasification of coal in a circulating fluidized-bed gas generator with a stagnant layer are described. The results of the experiments are consistent with simulation data. Based on a gas generator model, optimum process parameters—temperatures in gasification and combustion chambers, chemical efficiency, and coal fraction supplied to the gasification chamber—were found.

The applicability of carbon fibers as a combustible matrix in the template synthesis of nanostructured titanium dioxide was studied. It was found that the carbon matrix was completely combusted upon thermal treatment in a range of 500-800°C with an isothermal exposure at 800°C. As a result, the nanostructured fibers of titanium dioxide whose geometric dimensions repeated those of the initial carbon template were formed.

The experimental and theoretical studies of the gasification of solid organic compounds by a melt technology were carried out for the two types of carbon-containing materials: slime and tar. The experimental works and the simulation showed that this gasification method can be used for the effective utilization of oilrefining and petrochemical-processing wastes with the simultaneous production of high-purity synthesis gas.