Том 59, № 4 (2016)

For 63 samples of Ukrainian, Russian, and imported coal, equations for predicting the gross calorific value Q_s^daf on the basis of the following coal characteristics are developed: W^a, O_d^daf, Q_s^af, and C_ar. The error is within the standard tolerances (σ ≤ 0.3 MJ/kg). With sufficient accuracy, Q_s^daf may be predicted from equations based on petrographic characteristics such as the vitrinite reflectance, the content of liptinitegroup minerals, and the sum of lean macerals (I + 2Sv/3). In these equations, the coefficients correspond to the heat of combustion of the vitrinite components at different metamorphic stages, the liptinite, and the lean macerals.

The integral ignition characteristics of a single droplet (initial radius 0.3–1.0 mm) of various organic coal–water fuels (prepared by means of a homogenizer or a ball mill) in an oxidant flux at 800–1100 K are compared. The fuel samples are based on spent motor, turbine, and transformer oils, filter cake from K coal, water, and plasticizer. The influence of the drop radius, the fuel composition, and the method and duration of sample preparation on the properties of the fuel (in particular, its structural stability and viscosity in the initial state) and on its ignition characteristics (the ignition delay, the time for total combustion, and the duration of the initiation stage) is determined. The limiting duration of structural stability is compared for samples of organic coal–water fuel prepared by means of a homogenizer and by means of a ball mill.

The semicoking of residual humin from Berezovsk lignite is investigated, with and without additions of modifier. The maximum semicoke yield is observed at 450°C after 0.25 h. Converted for absolutely dry semicoke, it is 64–66%, regardless of the moisture content of the humin. The 11% increase in tar yield when using heavy tar from Arlansk petroleum as the modifier confirms these conclusions. The operational characteristics show that modified semicoke practically matches the properties of traditional reducing agents. Analysis indicates that the tar from the semicoking of residual humin is characterized by relatively high calorific value and contains mainly fractions with moderate boiling points. Accordingly, it may be regarded as a fuel.

The relation between the properties, composition, and structure of pitch and its modification on carbonization is considered. The basic stages in carbonization are determined, and a step-by-step carbonization model is proposed on the basis of thermal analysis and data regarding the changes in pitch composition and properties. The properties of pitch as a binder must be characterized by two parameters: one characterizing the formation of the blank; and the other characterizing its sintering.

Two promising catalysts are tested in the desulfurization of coke-oven gas at OAO Magnitogorskii Metallurgicheskii Kombinat in a pilot plant (with a gas flow rate of up to 0.78 m³/h): AOK-78-57 titaniumoxide catalyst (produced by OOO Katalizator, Novosibirsk); and VA-2 vanadium catalyst on an aluminumoxide substrate (developed at the Institute of Catalysis, Siberian Branch, Russian Academy of Sciences and produced by OOO Novomichurinskii Katalizatornyi Zavod). The VA-2 catalyst shows some benefits in the conversion of hydrogen sulfide, with practically the same activity in the conversion of organosulfur components (CS₂ and COS). With a final temperature of 450°C, CS₂ conversion at VA-2 catalyst exceeds 99.5%, on average. Accordingly, VA-2 catalyst is promising for use in the first stages of catalytic conversion in sulfurremoval units of Claus type, including those for the desulfurization of coke-oven gas.

The capacitive compensation of reactive power in the presence of harmonic distortion in the supply voltage is considered. Such distortion may be introduced both by factors in the external grid and by factors within the enterprise. That must be taken into account in selecting systems for reducing the effect of higher harmonics on compensating capacitor banks and improving the power quality at coke plants.