Coke and Chemistry最新文献

In the present research, means of reducing the content of the >80 mm class in metallurgical coke at coke batteries 1, 3, and 4 of Ural Steel are considered, in the light of the need to minimize batch cost and maximize coke quality (specifically, the strength indices M₁₀ and M₂₅). This problem was suggested by students in production education groups at the Novotroitsk branch of Moscow Institute of Steel and Alloys (MISIS). This first article in the series is a literature review, beginning in the 1960s. The influence of the following factors on the content of the >80 mm class is discussed: the rank composition of the batch; its moisture content; and coking parameters such as the coking time, the temperature in the controlled heating channels, and the coking rate. The second article will be devoted to mathematical analysis of a passive experiment based on Ural Steel data, with the goal of identifying the factors affecting the content of the >80 mm class in the coke produced at Ural Steel; the results of this analysis will be compared with literature data. The third article will present models of the content of the >80 mm class in the coke produced, with subsequent optimization and testing by laboratory coking.

The oxidation products of electrode pitch (category C) in a reactor with large gas capacity are considered. The influence of the oxidation time on the softening point and yield of volatiles in the production of high-temperature coal tar pitch is determined. In the experiments, the oxidation of electrode pitch is investigated as a function of the oxidation time and the maximum temperature. Oxidation occurs in the range 260–360°C. The air flow rate is 800 L/kg h. The yield of products, the softening point, and the yield of volatiles are determined as a function of the oxidation time. The increase in softening point may be attributed to the increase in oxidation time at temperatures above 300°C. The conditions for the production of high-temperature coal tar pitch by oxidation of electrode pitch are established. The dependence of the carbonizate yield on the oxidation time is determined.

The possibility of using petroleum coke and the pyrolytic carbon residue from scrap tires as a mixed fuel is considered. The influence of the coke/residue ratio (by mass) in the mixture on oxidation, ignition, and combustion is studied. The oxidation, ignition, and combustion characteristics of the samples are determined by thermal analysis and high-speed video recording in a combustion chamber at 1000°C. Increase in content of the carbon residue increases the reactivity of the mixture. Correspondingly, the initial temperature of intense oxidation T_i decreases (ΔT_i = 126°C) and the ignition delay τ_i is reduced (Δτ_i = 1.54 s). Likewise, there is an increase in the oxidation rate, determined by thermal analysis and on the basis of the unit heat liberation. Increasing the content of the pyrolytic tire residue results in less complete fuel combustion.

By comprehensive physical and chemical analysis, the suitability of carbonized sapropelic coal for use in supercapacitor electrodes and as a matrix for nanostructural composites is assessed. IR spectroscopy shows that the surface of the carbon material contains aliphatic and hydroxyl groups, as well as polyene groups. Analysis of nitrogen adsorption–desorption isotherms indicates that micropore structure predominates in the carbonizate: the mean pore diameter is 1.83 nm; the specific surface is 1472 m²/g; the total pore volume is 0.594 cm³/g; and the proportion of mesopore space is 31.7%. In terms of the size distribution of the pores, almost no pores greater than 5–6 nm are present. When the potential is scanned at rates of 1 and 10 mV/s, the electrical capacitance is 537 and 387 F/g, respectively. The results obtained for test cells on the basis of the galvanostatic charging and electrochemical impedance spectroscopy are consistent with data obtained by cyclic voltammetry. The capacitance data for the cells are determined on the basis of simplified equivalent circuits, using ZSimpWin software. Calculated and experimental Nyquist plots for the equivalent circuits are compared, and the Pearson consistency index is determined. There are good prospects for the use of carbonized sapropelic coal for use in supercapacitor electrodes and as a matrix for nanostructural composites.

This research focuses on how steeping with industrial mixtures based on lime affects the oxidative pyrolysis of coal of limited metamorphic development that is inclined to self-ignition. Passivating solutions considered include the filtrate and suspension of a lime solution, which are traditionally used to suppress coal oxidation. Treatment of coal with lime solutions is accompanied both by physical adsorption of calcium ions on the nonuniform coal surface and by chemical reaction with functional groups that are susceptible to oxidation. The fundamental differences in the oxidation of coal of little and moderate metamorphic development with lime solutions are identified. After treatment of coal surfaces with lime solutions, less oxidation is observed.

Petroleum pitch is a valuable raw material in many industries. It is in considerable demand: 10⁴–10⁵ t/yr. In the present work, the physicochemical properties of thermally cracked decantoil (decanted heavy gas oil) and its 250°C fraction are investigated by standard methods used for petroleum derivatives. In terms of its group composition, content of condensed polyaromatic compounds, coking properties, and sulfur content, these materials are suitable for the production of binders used in the electrode industry and carbon–carbon construction materials.