Vol 60, No 2 (2017)

The composition and properties of Kemorovo lignite are studied. Lignite is characterized by high moisture content and yield of volatiles, high chemical activity, and a high content of micro- and mesopores. The moisture absorption and moisture loss of lignite (piece sizes 3–8, 8–12, 12–25, and 25–50 mm) are studied as a function of the contact time with water and air. Industrial data are presented for the lignite temperature on storage in the batch yard at AO Kuznetskie Ferrosplavy. When a probe is introduced in the coal to depths of 400–1000 mm, its temperature varies from 68–78 to 78–90°C. With increase in holding time, it rises to 83–93°C. Recommendations are made for refinement of the technical instructions regarding lignite storage.

In assessing the operational efficiency of dry-quenching units at coke plants, it is important to consider the coke losses. In the present work, existing methods of determining the coke losses are analyzed. The method selected is based on continuous measurement of the flow rate and composition of the excess circulating gas released from the dry-quenching unit; it is compatible with different coke-discharge systems. Methods of determining the productivity of the dry-quenching unit are assessed. Means of reducing the coke losses are discussed.

The heat treatment of the anthracene fraction of coal tar under pressure is considered. In the production of synthetic pitch, the duration of the process is varied from 10 to 80 min, at a temperature of 500°C and a pressure of 3 MPa. Kinetic data for the formation of γ and α₁ fractions show that the polycondensation of the γ fraction is of second order, while the formation of the α₁ fraction is of zero order. Pitch obtained with holding for 10–40 min does not contain the α₁ fraction. Extending the process beyond 30 min does not affect the removal of heteroatoms. IR spectroscopic data indicate that dealkylation predominates for the first 40 min. Then the process slows, and compaction develops.

Processing of the industrial waste formed at steel plants is of great importance. In the converter production of steel, 12–25 kg of fine dust is formed in the production of 1 t of steel, depending on the composition of the raw materials, the furnace design, and the smelting conditions. Wet cleaning of the waste gases converts the dust into a slurry containing 46–50% Fe₂O₃. It is difficult to process such slurry because of its high water content, the small particle size, and the presence of zinc oxides. Standard dehydration technology is complex. It is also associated with thermal drying, which poses an explosion risk, while briquetting or granulation does not resolve the problem posed by the presence of zinc oxides and is complicated by a lack of acceptable binders. Researchers at Siberian State Industrial University have developed complex conditioning of iron-bearing slurry by nonthermal adsorptive dehydration and subsequent thermochemical agglomeration, with simultaneous reduction of the iron and zinc oxides. Adsorptive dehydration to a moisture content of 2‒3% is possible by contact with porous lignite semicoke produced by Termokoks technology. Then the lignite semicoke is pneumatically separated and sent for use in energy systems, while the iron-bearing product is mixed with GZh or Zh coal and sent for thermooxidative coking in a furnace of special design (an annular furnace with a rotating hearth), where large and strong pieces of ferrocoke are obtained at 1050–1100°C. The ferrocoke contains 55–60% of the iron-bearing product. The oxides of iron and zinc are almost completely reduced. The zinc passes to the vapor phase and is removed with the combustion products of the volatile coking components. On cooling to 850°C, the zinc vapor condenses. The ferrocoke obtained is suitable for blastfurnace use, thereby reducing the consumption of sinter and coke. The heat obtained on cooling the ferrocoke and the energy of the combustion products after the deposition of zinc are utilized in a gas-turbine system.