Vol 60, No 6 (2017)

The ignition temperature of binary coal mixtures is determined. The mixtures contain coal of different metamorphic development, in various proportions. Systematic deviation of the actual ignition temperature from the values calculated on the basis of the sum rule is observed; the actual ignition temperature is lower. Statistical analysis shows that these deviations are significantly nonrandom. A formula is derived for predicting the ignition temperature of 50 : 50 binary mixtures on the basis of the ignition temperatures of their components. It appears that, in the mixtures, the component with the lower ignition temperature is ignited first. The energy liberated is consumed in the ignition of the less flammable component. That results in ignition of the mixture as a whole.

Defects in coke-oven linings of coke batteries are analyzed. In the course of operation, the properties of the Dinas brick change on account of the formation of silicate melts that move through a capillary system within the brick from hotter to cooler sections of the lining. Melt migrates from the vertical heating channels to the coke chambers. In contrast to most of the heating channels, significant temperature gradients arise between the extreme and adjacent heating channels on account of the great difference in the quantity of heating gas supplied. The temperature gradients facilitate melt migration in this zone not only from the vertical channel to the chamber but also between vertical channels. This factor accelerates lining wear at the extreme heating channels and must be taken into account in regulating the heating conditions at the extreme pairs of heating channels.

The heat treatment of high-boiling tar fractions from Berezovsk lignite (Kansk–Achinsk Basin) in a solid-fuel reactor to obtain lignite pitch is investigated. In addition, the use of the semicoke to reduce granulated phosphorus pellets from Dzhanatas ore is studied. The lignite pitch and semicoke may also be used in coking batch for the production of blast-furnace coke with improved properties; as binder in the production of domestic lignite-based fuel briquets; as binder in the sintering of Kovdorsk and Olenegorsk iron-ore concentrates at AO Severstal’; as binder in the production of anode masses for aluminum production; as binder in bricks and cold packing employed in the manufacture and sealing of electrolyzer hearths; and for pyrolysis with natural methane to increase the yield of ethylene.

The characteristics of synthetic diesel fuel are analyzed. The fuel consists of hydrocarbons C₃–C₃₂; the content of the middle fractions is 83.26 wt %. The IR spectrum of the synthetic diesel fuel contains deformational vibrations corresponding to paraffins and unsaturated hydrocarbons, as well as aromatic and heteroaromatic compounds. Synthetic fuel produced from coal is recommended as a raw material for DTZ commercial diesel fuel, suitable for use in winter.

The factors responsible for the high chemical oxygen demand (COD) of biochemically treated coke-plant wastewater are identified. The factors responsible for overestimation of the COD in bichromate tests are also determined. Experiments show that the interference of inorganic reducing agents formed in biochemical treatment must be eliminated in determining the COD. To reduce the consumption of the reagents used to improve the results of COD tests (including the need for toxic mercury sulfate), special methods of preparing the wastewater samples are recommended.