Coke and Chemistry最新文献

IR spectroscopy of petroleum residue may be used to assess the microstructure and yield of volatiles of the coke produced. The structural and group characteristics of the petroleum components used in coking—catalytic cracking gas oil, tar sludge, heavy pyrolytic tar, and selective purification extract—are established by IR spectroscopy. The coke’s microstructure and yield of volatiles are determined as a function of the parameters X and Y based on the structural and group characteristics of the petroleum components.

This paper conducts an analysis of thecharacteristics of horizontal heat recovery coke and its application in large-volume blast furnaces. Based on the different structural models of coke used in blast furnaces, a systematic analysis is carried out. At the same time, measures such as adjusting the quality of the coke itself and the operational system of the blast furnace are implemented. The technology for the large-scale application of horizontal heat recovery rammed coke in blast furnaces with a capacity of 1500 m³ and above is developed. This enables a 20–40% increase in the usage ratio compared to the conventional usage ratio, and a long-term stable usage ratio of over 80% is achieved. The goal of achieving efficient and stable operation of the blast furnace is also realized.

The organic components in coal tar from the waste dumps at Qarmet coke plant are identified by gas–liquid chromatography. The analysis yields the following results: 29.41% naphthalene and its derivatives; 3.42% acenaphthene; 3.94% dibenzofuran; 4.18% fluorene; 4.98% phenanthrene; 0.91% anthracene; 2.45% fluoranthene; and 0.94% pyrene. Medium-temperature pitch is obtained by vacuum distillation of coal tar from dump 1 at the Qarmet plant. Many characteristics of the pitch—such as the content of toluene-insoluble components (40.56%), softening temperature (85–90°C), and yield of volatiles (54%)—correspond to the standard for grade-B electrode pitch.

A method is proposed for improving the bed gasification of lignite with an inverse air blast. The dependence of the unit sorbent output on the moisture content of the initial lignite is studied. The influence of the initial moisture content and the gasification temperature on the sorbent’s properties is investigated. By reducing the moisture content of the initial lignite, the productivity may be increased more than fourfold, without loss of sorbent quality.

The ignition of mechanically active coal at different stages of metamorphic development in boilers at thermoelectric power plants is considered. In experiments on coal ignition, a vertical tubular furnace is employed. The reactivity of coal activated in a disintegrator is determined by thermogravimetric analysis. The results indicate that the ignition temperature of mechanically activated coal in a vertical tubular furnace is considerably lower than that of the initial coal. On that basis, the fuel oil generally used for flame ignition may potentially be replaced by coal. The ignition and combustion parameters required for different types of fuel are determined. The components of the flux of gaseous combustion products for different types of coal are detailed, and the characteristics of alternative methods of heat generation are compared. The results may be used in the construction and modernization of power stations.

Coal samples from selected Nigerian coal mines were analyzed for their combustion performance and kinetics. The combustion characteristics were investigated using thermogravimetric analysis at a constant heating rate of 10°C/min. The relationship between the combustion properties and pore structure was also assessed. The pore structure was studied by Brunauer–Emmett–Teller analysis. The Arrhenius equation and Coats–Redfern methods were employed to determine the kinetic parameters from the thermogravimetry/derivative thermogravimetry curves. The ignition temperatures were 280, 300 and 320°C for the Inyi, Ogboyega and Ribadu coals, respectively, whereas the combustion indices were –1.43E-9, –3.35E-9, and ‒1.44E-10 for the Inyi, Ogboyega and Ribadu coals, respectively. Compared with coals from other mines, the Ribadu coal has a greater pore surface area at 3.985E+02 m²/g and pore volume at 2.239E-01 cc/g. The results revealed that higher ignition and flammability indices are associated with lower pore surface areas and volumes. The activation energy varied between 15 and 17 kJ/mol when calculated using the Arrhenius method and from 43 to 52 kJ/mol when calculated using the Coats–Redfern method. The Arrhenius model gave higher coefficient values than the Coats–Redfern kinetic model. The activation energies of the tested coals are relatively low, which suggests that they can be utilized in power generation. This study provides necessary information in the evaluation of the tested coals for efficient utilization through combustion.

Precarbonization is a crucial step in the graphitization of petroleum coke to produce anode materials, and its caking property adversely affects the stable operation of this process. Using caking petroleum coke as the raw materials, the caking properties were determined with characterization parameters and a pre-oxidation method was proposed to destroy the caking tendency during precarbonization in this study. The caking characteristics of different types of petroleum coke were analyzed, and the effects of pre-oxidation temperature, time, and petroleum coke type on caking destruction were investigated. The experimental results showed that: (1) The caking characteristics varied significantly among different petroleum coke; the caking index correlated with the volatile content but was unrelated to sulfur content. (2) The caking tendency of petroleum coke decreased with increasing pre-oxidation temperature and extended reaction time. (3) The same pre-oxidation conditions yielded different caking destruction effects on different petroleum coke. Fujian low-sulfur petroleum coke (FJ) achieved complete caking destruction (caking index decreased from 72.02 to 0%) after reacting in air at 250°C for 10 min. (4) The pre-oxidation process had no impact on the subsequent graphitization process of petroleum coke, making it a practical and promising method for destroying the caking tendency of petroleum coke.

The influence of treatment with various gases on the surface wettability of coal of early and intermediate metamorphic stages is studied. The wettability is assessed by water filtration through a bed of coal powder. For coal samples prepared in air, the filtration rate is higher on account of surface oxidation and greater hydrophobic activity of the contacting layer. The worse filtration properties of coal samples prepared in nitrogen and CO₂ indicate greater hydrophobic activity of their surfaces. The influence of CO₂ and nitrogen on the filtration properties is greater for coal of little metamorphic development, perhaps because of molecular interactions (hydrogen bonds) and chemical reactions (carbonate formation) of the CO₂ molecule with polar functional groups of the coal.

The parameters of three-phase foam derived from coal flotation waste are studied. Liquid flotation wastes and suspensions with different concentrations of solid wastes are considered. The experimental results indicate that raising the temperature increases the expansion ratio of the foam and decreases its stability. That must be taken into account in localizing the self-ignition hotspots in coal mines. The components used in the flotational enrichment of coal impair foam formation, reducing the expansion ratio and stability of the foam. The foam parameters are investigated as a function of the proportion of solid flotation waste in the foam-forming liquid. To obtain maximum foam volume, a suspension containing 17–25 wt % solid flotation waste is recommended.

The economic condition of Russian coal companies is considered. The causes of recent problems are outlined. The scale of potential losses at mining companies due to sanctions, which disrupt prior logistical patterns, is determined. The need to identify and take account of the industry’s environmental hazards and loss of income is established. Not only financial risks but also engineering and organizational losses in coal extraction and processing are inevitable. That necessitates the study of key economic indicators for Russian coal companies. It is clear that economic indicators must be developed for coal companies and standardized within the framework of uniform organizational documentation regarding industrial and accounting policies. By studying the economic returns for priority products at the largest Russian coal companies, the prospects for economic entities to process coking coal and lignite and to produce anthracite and thermal coal are compared. Risks are viewed through the prism of five approaches to assessing and regulating economic losses: technological, professional, energy, commercial, and fiscal (tax) risks. Means of minimizing the losses in each category must be adapted to the actual processes of mining and processing coal and obtaining the final product, taking account of industrial and environmental safety requirements.