Coke and Chemistry最新文献

Coke is the fuel and main support for creating permeability in the blast furnace in the steel industry. It is produced by blending various types of coal. Therefore, studying the relationships between the intrinsic properties and preparation parameters of coal with the quality of the resulting coke is essential. Coke texture and mean size are the critical structural indicators of cokin, which also influence the reactive properties and Strength of the produced coke. In this study, the relationship between coke texture indices, the intrinsic properties of coal, and coal preparation parameters was evaluated for three types of Iranian coal. Regression analysis and Design Expert software were utilized for this purpose. To better understand the relationships between coal’s intrinsic properties and its reactive characteristics. FTIR, XRF, and SEM analyses were conducted. Regression analysis revealed correlations between four intrinsic properties of coal (ash content. volatile matter, fixed carbon content, and maceral composition) and two key coke texture indicators (pore count and coke porosity). The highest coefficient of determination (R²) values were observed in the relationships between liptinite content and pore count (0.94) and between liptinite content and porosity percentage (0.87). Additionally, the study on coal blending ratios demonstrated that coal with a higher inertinite content exerted greater control over the number of pores and the porosity percentage of the produced coke when present in finer particle sizes.

The influence of oxyethylated alkyl phenol (Neonol AF_9–10) on the clarification of coal tar in mechanized settling tanks is considered. Adding Neonol is found to increase the deposition rate of tar sludge. If Neonol is present in the wastewater sent to the biochemical treatment plant, its operation is not significantly affected. The use of Neonol in the separation of water–tar mixtures decreases the content of tarry impurities. Ash removal from tar in mechanized settling tanks may be intensified by adding Neonol, with decrease in the rate at which sediment builds up in tar stores. The stability of water–tar emulsions declines on adding Neonol. On the basis of these results, the use of Neonol may be recommended to stabilize the quality of coal tar.

The texture and surface state of Purolat Standard sorbent are studied before and after the sorption of ferrous ions from aqueous solutions, by various instrumental methods. The presence of iron at the surface largely affects the sorbent’s organic compound. The extraction of iron is accompanied by partial destruction of the sorbent surface, possibly as a result of both the oxidation of amorphous carbon and the conversion of phenol and simple ester groups to carboxyl groups. The adsorption of iron ions may occur mainly by ion exchange but also by complex formation with groups at the carbon surface. IR spectroscopy suggests that the ferrous ions are adsorbed at the surface in the form of hydrated complexes.

Spectral analysis is employed to compare oxidized and unoxidized coal samples and the humic acids and fulvic acids derived from them. Differences between naturally oxidized and unoxidized coal samples include increased yield of volatiles and humic materials; higher content of analytical moisture, ash. and moisture, and higher total content of oxygen, nitrogen, and sulfur (O + N + S); but lower carbon content. The greatest yield of humic materials is observed for oxidized 1B and 2B lignite (70.5%, consisting of 60.9% humic acids and 9.6% fulvic acids). The yield of humic materials is also high for oxidized long-flame D coal (42.4%, consisting of 34.8% humic acids and 7.6% fulvic acids). The yield of humic materials from G coal is minimal: no more than 0.7%. According to Fourier transform infrared (FTIR) spectra and CP/MAS ¹³C nuclear magnetic resonance (NMR) spectra, the structural group composition of the humic acids is largely determined by the composition of the initial coal. The content of aromatic structure f_ar and the hydrophilic/hydrophobic balance f_h/h calculated from the ¹³C NMR spectra for the coal samples and humic acids are directly related (R² = 0.71 and R² = 0.81, respectively). The structural group composition of the fulvic acids is largely unaffected by the composition of the initial coal and is more uniform. Overall, f_h/h is higher for oxidized coal than for the corresponding unoxidized coal. The humic acids have a larger content of carbon and aromatic fragments. The fulvic acids have a larger content of oxygen-bearing aliphatic groups. The elemental composition and structural group composition of the humic and fulvic acids from oxidized G and D coal samples are comparable with those for the lignite samples.

Options for organizing the regasification of liquefied natural gas (LNG) with the Rankine cycle are compared, with a view to more effective use of the cold energy of the liquefied gas. The comparison is based on exergy efficiency: the ratio of the total thermal inlet and outlet exergy for the system. In calculating the thermal characteristics of the flow, components of thermal exergy that don't change are discarded. ChemCad software is used for computational experiments. In organizing the regasification of liquefied natural gas (LNG) with the Rankine cycle, the heat source employed is seawater or flue gas at the output of turbine-based thermal power systems. When using environmental resources (seawater) at marine terminals, the efficiency of regasification proves higher than when using flue gas. However, the power generated in the Rankine cycle is 2.4 times greater when using flue gas. In addition, when using the residual heat of the flue gas, the heat pollution of the environment may be significantly reduced. All in all, the use of flue gas can be more economically viable.

The prospects for using carbon substrates produced by the high-temperature (800°C) alkaline (KOH) activation of A and D coal and sapropelic coal are considered. Active particles are subsequently applied to the surface of the carbon substrates so as to obtain functional materials. The results of IR spectroscopy and technical analysis, as well as differential scanning calorimetry, indicate that the carbon substrates produced from D coal are the most promising. The presence of numerous –OH and –C=O groups in that case facilitates the reduction of metals at the carbonized surface, and hence the active particles at its surface are more disperse.

The synthesis of mineral polymer materials from fly ash offers a sustainable utilization strategy. This study employed a sol−gel method to prepare silica-alumina precursors, investigating the effects of synthesis parameters such as silicon and aluminum sources, temperature, Si/Al ratio, and ethanol dosage. Structural and physicochemical properties were analyzed using XRD, SEM, TG, and IR spectroscopy. Optimal conditions were identified at a Si/Al ratio of 10 : 1, a synthesis temperature of 60°C, and calcination at 750°C for 3 h, achieving a maximum synthesis efficiency of 81.33%. XRD confirmed an amorphous phase with a grid-like structure, while IR analysis revealed Si–O–Si bonding and characteristic absorption peaks at 806 and 1395 cm^–1, indicating incomplete reactions. SEM imaging showed uniform, fine particles. These findings enhance the understanding of silica-alumina precursor synthesis, providing insights for their application in advanced materials.

This study investigates the impact of a CO₂-rich environment on the aluminosilicate gel in alkali-activated fly ash (AAAFA) using NMR spectroscopy. After 24 h of curing at 80°C, the AAAFA samples were exposed to a 10% ambient CO₂ concentration. Highly reactive elements such as Na and Al fully reacted within the initial hours and remained unaffected by carbonation under high CO₂ levels. However, Si, which reacts more slowly, exhibited distinct behaviour. Monomeric silicates rapidly polymerized despite the carbonated sample showing a lower overall reaction extent. This indicates the formation of a binding gel phase due to intense CO₂ exposure, leading to an increased gel content in the carbonated sample. These findings enhance the understanding of aluminosilicate gel chemistry and behavior under elevated CO₂ concentrations, providing insights into the long-term performance of alkali-activated materials in carbon-rich environments.

Fuel economy in boilers is an urgent concern. Coal combustion with fuel oil is currently employed for that purpose, but this approach impairs electricity generation and releases oxides of sulfur and nitrogen into the environment. An alternative is oil-free combustion with plasma activation of the coal. Preliminary plasma activation results in more efficient combustion in the absence of fuel oil. The effectiveness of this technology is confirmed by familiar methods: engineering analysis, economic assessment, elaboration of a theory, experimental testing, and formulation of recommendations for optimizing the technology. The influence of plasma activation on the coal combustion is studied. The resulting technology for thermal preparation and combustion of coal in a cyclone furnace is an alternative to combustion with fuel oil in industrial boilers. The design of the system for regulating combustion with partial gasification of the working fuel is improved. Using this technology, it proves possible to use low-grade coal as the fuel. The emission of nitrogen oxides is decreased, and boiler performance is improved. Oil-free fuel combustion in a cyclone furnace is promising for use in power generation. It is shown that coal combustion with chemical activation or high-temperature plasma activation may be used in modernizing or constructing thermal power stations.

In considering the dynamics and structure of coal production at the largest Russian mining companies, their financial and economic position is analyzed. Priorities for the development of coal mining in Kemerovo oblast are determined. Problems are also identified, including the industry’s significant environmental impact. The consolidated budget of Kemerovo oblast shows large financial losses. The numerous economic and environmental factors responsible for the poor performance of the coal industry are noted, including decreased coal exports due to international sanctions; significant fiscal support for large coal companies, with low return on the infrastructure projects concentrated in the hands of small and medium companies; and violation of environmental standards for coal mining, with colossal financial penalties to mining companies that lack treatment facilities. A system is proposed for the state support of coal mining in Kemerovo oblast so as to stimulate stable growth of coal output, to introduce innovative projects at state mining enterprises in the Kuznetsk Basin, and to support and manage infrastructure projects in the regional coal industry with an emphasis on risk-oriented technologies.