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Том 61, № 5 (2018)
- Год: 2018
- Статей: 6
- URL: https://journal-vniispk.ru/1068-364X/issue/view/13971
Coal
Thermal Decomposition of Oxidized Long-Flame Coal
Аннотация
The influence of oxidation of long-flame coal pieces (at 100–250°C for 5–40 h) on the yield and composition of the pyrolytic products, the emission dynamics of volatiles, and the properties and porous structure of the semicoke is studied.
153-164
IR Spectroscopy in Rank and Group Assignment of Coal
Аннотация
The possibility of express determination of the characteristics VIRdaf, Ro, IR, yIR, ΣLCIR, and AIRd used in the ranking of coal on the basis of IR spectroscopy is assessed for a specific example: Kuznetsk coals of different maceral composition and metamorphic development. The IR characteristics are compared with values obtained by standard methods (Vdaf, Ro, r, y, ΣLC, and Ad).
165-170
Coke
Improving the Preparation of Coking Batch
Аннотация
Currently, the most promising blast-furnace technology involves pulverized-coal injection, and the most promising blast-furnace technology for coke production involves ramming the coal batch before delivery to the coke ovens, so as to ensure high packing density. In classic bed coking, the packing density of the coal batch is also of great importance. In the absence of mechanical methods (such as ramming or partial briquetting), the packing density mainly depends on the ash and moisture content and the degree of crushing of the batch. It follows from industrial tests in the coke plant at PAO ArcelorMittal Krivoy Rog and analysis of the multifactorial correlation of the strength M25 and wear resistance M10 with the packing density of the batch that, with decrease in packing density, the coke strength and wear resistance decline. That increases coke consumption and considerably complicates blast-furnace operation. Since improvement in coke quality entails decreasing the moisture content of the coal batch, a method has been developed for decreasing the moisture content directly in the silo, on the basis of osmosis and vacuum, that permits decrease in the coal’s moisture content to the optimal value, thereby boosting coke quality and improving blast-furnace performance. For example, it has been established that, in the blast-furnace shops at PAO ArcelorMittal Krivoy Rog, 1% decrease in M10 lowers the mean coke consumption by 5.5%. With increase in M25 by 1%, the mean coke consumption falls by 2.1%, on average.
171-178
Chemistry
Electrical Conductivity of Carbon Materials Based on Coal-Tar Pitch with Added Graphite Foam
Аннотация
Attention focuses on the structure and electrical conductivity of carbon materials produced by the carbonization (at 900°C) of coal-tar pitch with the addition of 0.03–0.3% graphite foam and oxidized graphite foam. In these quantities, the additives do not change the X-ray diffraction characteristics but considerably increase the conductivity of the product over the whole temperature range. With increase in concentration of the additives, the conductivity of the carbon material increases. At room temperature, it is 14–20 S/cm, which is at least 2–3 times the value in the absence of the additives. The influence on the conductivity is greater for the oxidized graphite foam. This may be attributed to the smaller size of the crystallites and the greater distance between the planes, resulting in greater accessible surface area of the graphite layers orienting the pitch molecules on carbonization.
179-183
Electrical Resistivity of Coal and Oil Shales
Аннотация
The physicochemical properties of coal and oil shales are compared: specifically, the ash content, moisture content, porosity, and yield of volatiles. The electrical resistivity of the oil shales, lignite, and coal is compared, as a function of the temperature. On account of their large content of volatiles, lignite and oil shales are characterized by similar electrical resistivity.
184-187
Environmental Protection
188-192