Solid Fuel Chemistry最新文献

This paper takes the working face of Heiyanquan Mine as the research subject. Based on the mechanism of coal self-ignition and the gas generation pattern, combined with coal oxidation and temperature rise experiments and machine learning algorithms, a prediction and early warning model for spontaneous combustion risk in goaf areas is constructed. The results show that the double-layer random forest model optimized by grid search and cross-validation has a mean absolute error (MAE) of 6.47 and a determination coefficient (R²) of 0.9845, with a prediction relative error between 0 and 5%. When the working face was advancing slowly through a fault, the model projected that the peak temperature at a depth of 72 meters in the goaf area reached 49.2°C and surpassed 40°C for five consecutive instances, indicating a spontaneous combustion risk. After calculation and numerical simulation, a prevention and control plan was determined with a nitrogen injection flow rate of 9 m³/min and a nitrogen injection port 65 meters away from the working face. During the nitrogen injection process, the system continuously predicted and warned. When the measurement point No. 4 was located at a depth of 105 meters in the goaf area, it was determined that there was no risk of spontaneous combustion, and nitrogen injection was stopped. The findings offer a scientific, accurate, and efficient method for controlling spontaneous combustion in coal mine gob areas, which helps enhance the effectiveness of fire prevention and extinguishment.

Coal is a complex mixture consisting of organic macerals and minerals. The presence of minerals can give rise to variations in the macromolecular structure of coal, modify its pore structure, and subsequently influence the coal’s adsorption capacity. Taking bituminous coal and kaolinite minerals as the research subjects, this study quantitatively investigated the impact of kaolinite and its content on the adsorption properties of bituminous coal using the molecular dynamics method. Moreover, the pore characteristics and adsorption energy of bituminous coal under different mineral contents were analyzed to uncover the underlying microscopic mechanism.The results demonstrate that as the mass fraction of kaolinite increases, the total volume, free volume, and porosity of the coal macromolecules composed of bituminous coal and kaolinite all increase. Additionally, with an increase in the kaolinite mass fraction, the adsorption capacity of CO₂ also rises. The adsorption heat ranges from 24.57 to 32.97 kJ/mol under different mass ratios, and it increases in tandem with the growth of the adsorption capacity. As the mass fraction of the minerals increases, the peak value of the radial distribution function between bituminous coal and kaolinite goes up, indicating that the probability and interaction intensity of CO₂ molecules surrounding bituminous coal molecules increase with the rise in mineral content. Kaolinite molecules exhibit a strong interaction with CO₂, and CO₂ molecules are more densely packed within the kaolinite-containing structures compared to those in bituminous coal. Under the same time conditions, the self-diffusion coefficient of CO₂ molecules in the kaolinite-containing structure is higher than that in the bituminous coal structure, suggesting that the adsorbed gas in the kaolinite-containing structure is more stable. Furthermore, as the quantity of kaolinite increases, the porosity grows, and the self-diffusion coefficient of CO₂ molecules also increases.This research offers a theoretical reference for coalbed methane (CBM) exploitation and carbon sequestration.

The anthracite in Yangquan mining area contains intrinsic pyrite, and there is a considerable content of associated pyrite in the coal seam, which are easy to cause coal spontaneous combustion and seriously restricts the mine safety. In order to study the influence of intrinsic pyrite and associated pyrite on coal spontaneous combustion, the different contents of intrinsic pyrite in coal were removed by physical flotation and the associated pyrite was added to desulfurized coal. The synchronous thermal analysis and temperature-programmed chromatography were used to determine the difference of two kinds of pyrite on coal spontaneous combustion. The results suggested that with the increase of intrinsic pyrite content in coal, the characteristic temperature of coal decreases, the weight gain, the heat release increases and the release of SO₂ increase, and the index gas production and activation energy also show an increasing trend. When the associated pyrite is added to the coal with the lowest intrinsic pyrite content (WK15-4), the weight, heat release and index gas release intensity also show an increasing trend, while the characteristic temperature decreases. The comparison shows that both AP and intrinsic pyrite of coal can promote coal spontaneous combustion, but the ability of AP to promote coal spontaneous combustion is stronger than that of intrinsic pyrite.

Beginning in the 1930s, a number of technological processes were developed to saturate the market with affordable detergents; these processes are still used today, almost a century later. While various fractions of hydrogenated vegetable oils and spermaceti from cetaceans were initially used as raw materials for soap production, the use of petrochemical raw materials began in the mid-20th century largely due to the efforts of the scientific community and the development of chemical technologies and organic synthesis. To date, a number of methods have been introduced or are close to being introduced into industry: hydrogenation, the Bouveault–Blanc method, the Bashkirov method, the SHOP process, and the Ziegler process, and technologies for the biosynthesis of higher fatty alcohols from gas-chemical feedstocks. This paper aimed to summarize the accumulated experience of science and industry, observe currently available methodological approaches to the synthesis of higher fatty alcohols from various raw materials, demonstrate the advantages and disadvantages of these approaches, and outline the prospects for the use of higher fatty alcohols and by-products of their synthesis in the Russian Federation.

The paper presents the results of studies on the effect of process parameters (temperature, hydrogen pressure, reaction time, and coal/tetralin weight ratio) on the hydrofluidization of Barzas sapromixite in the presence of a hydroaromatic hydrogen-donor solvent (tetralin) and catalytic additives (2.5 wt % Fe₂O₃, 0.5 wt % MoO₃, and 2.5 wt % Fe₂O₃ + 0.5 wt % MoO₃). It was found that the yield of the liquid products of sapromixite conversion initially increased with the heat treatment temperature; then, it passed through a maximum at ~450°C and decreased above this temperature. Based on the experimental studies, the following optimal conditions for liquefaction of Barzas sapromixite were determined to ensure the yield of liquid component fractions of 55–60 wt % based on the organic matter of coal upon its heat treatment: T = 450°C, ({{P}_{{{{{text{H}}}_{{text{2}}}}}}}) = 12–13 MPa, t = 20 min, and weight dilution of coal/tetralin = 1 : 2. It was shown that the yield of carbon residue significantly decreased with the addition of the catalysts, but the yields of liquid and gaseous compounds increased to indicate an increase in the degree of conversion of the sapromixite and the formation of lighter products.

Adsorption has numerous advantages over other wastewater treatment methods. Since it has the best sorption qualities and is a flexible adsorbent, biosorbent derived from biochar has been employed extensively to remove chemical species from their aqueous solutions. Hemidesmus Indicus, a new biosorbent, was used to study the biosorption of the anionic dye Congo red from aqueous solution. Variations in solution initial dye concentration, contact time, and temperature were used to determine the ideal sorption conditions. In batch adsorption investigations, Hemidesmus indices efficiency in eliminating Congo red dye as a bio adsorbent is investigated in this work, along with factors including dosage, pH, and beginning dye concentration. Congo red dye was shown to be more readily absorbed by surfaces treated with KOH compound, UV-visible adsorption spectroscopy is used to measure dye decolourization, and Analyzes surface morphology changes like pore structure, roughness, surface deposition or blocked pores are determined by FTIR and SEM with EDAX are used to examine the adsorbent’s altered surface properties. Congo red dye was shown to be more readily absorbed by surfaces treated with KOH compound, leading to elimination percentages of 51, 73.4, 54.26, 52.36, and 42.54%. Adsorption efficiency is evaluated using mathematical evaluation such as the Adams-Bohart and Yoon Nelson model; the equilibrium isotherm data model’s adsorption-derived R² values are 83.26, 91.5.67 and 74.51.

Here, the organic concentration in wastewater is reduced using a Digital Baffle Batch Reactor (DBBR) for new process electro catalytic and electro coagulation process (EC&ECP), which is based on an anatase titanium oxide (anatase-TiO₂). The work deals with the treatment of simulated reactive blue wastewater (RBWW) through electro of coagulation and oxidation in a batch electro-catalytic reactor by means of aluminum and iron as anode and cathode resources correspondingly. All these data based on the results obtained from characterization such as SEM, XRD and FTIR. Belongings of operating issues for example titanium dioxide (15–45 ppm), pH (3–9), and time (10–50 min) and (5–20 ppm) concentration of reactive blue on the organic removal (OR) were deliberate. The consequences revealed that titanium dioxide concentration has the chief result on the competence of OR confirming that the hybrid was ruled through reaction circumstances in the RBWW solution. Parametric optimization was approved out by means of response surface methodology combined with Box Behnken Design toward make the most of the OR. Below enhanced working circumstances, the organic elimination was found to be 98.9%. The new reactor design (DBBR) provided the reactivity the anatase-TiO₂ made using new process the electro catalytic and electro coagulation (EC&ECP) and achieve a high organic removal rate, resulting in clean water. Additionally, the new reactor, material, and EC&ECP process have not all been met in a single process, and this is thought to be the first investigation in this field.

To address the severe issue of spontaneous combustion in residual coal within gob areas under gob-side entry retaining conditions, this study investigates fire prevention strategies during coal mining operations at the 22523 working face of Halaigou Coal Mine through integrated field measurements, experimental analyses, and numerical simulations. The findings reveal that the spontaneous combustion risk zones in gob-side entry retaining faces can be categorized into two distinct regions: the rear section of the working face and the gob-side entry area. The hazard distribution behind the working face demonstrates similarity to conventional “U”-type ventilation patterns, while the combustion risk in the entry-retained side primarily arises from the combined effects of leakage through flexible formwork walls, residual coal distribution patterns, and inherent coal oxidation characteristics. Progressive analysis demonstrates that the maximum oxidation zone and peak temperature locus migrate from the return air side toward the gob-side entry area with advancing face progression. Comparative evaluation of nitrogen injection strategies (single-point, uniform multi-point, and self-regulating multi-point configurations) demonstrates that the self-regulating nitrogen injection system achieves superior fire suppression efficacy compared to single-point injection while reducing nitrogen consumption by 43.3% relative to uniform multi-point injection. These empirical findings establish the technical and economic viability of the self-regulating injection protocol for practical implementation at the 22523 working face.

To investigate the dispersion and complex propagation of toxic and hazardous hot gas clouds in mine ventilation networks following gas explosions, this study examines the Tunlan Mine “2.22” gas explosion accident. A simulation model of the Tunlan Mine was established, and gas explosion experiments were conducted to determine the initial concentration and temperature distribution of the gas cloud post-explosion. The TF1M3D simulation platform was utilized to model the post-explosion migration and spread of CO-deficient hot airflow under various ventilation conditions. The simulation revealed that when the Liangzhuang return air shaft fan failed for 30 min, CO-deficient hot airflow dispersed throughout the mine under the influence of other ventilation fans and residual explosion heat. After ventilation was restored, the hazardous airflow was completely expelled from the mine within 30 min. The simulation demonstrated that the hazardous airflow changed direction twice before and after the restoration of the Liangzhuang return air shaft fan, affecting working faces 12 403 and 12 405 twice and exacerbating the disaster’s impact and spread. The influence of self-rescuer time limits on personnel evacuation was analyzed in relation to the disaster airflow propagation process. The simulated disaster propagation patterns aligned with actual events. Drawing lessons from the accident, ventilation control strategies to facilitate personnel escape and mitigate disaster spread are proposed, providing reference for emergency ventilation control in mine gas explosions.