Solid Fuel Chemistry最新文献

In order to study the tensile properties and crack evolution of bedding coal under splitting load, Brazilian splitting tests were conducted on bedding coal. Results indicate distinct anisotropic mechanical properties of bedding coal. When the bedding dip angle is 0°, the coal sample exhibits the highest tensile strength and splitting modulus, followed by 30° and 90°, with the lowest values observed at 60°. Under the Brazilian splitting load, the crack propagation mechanism for coal samples with a bedding dip angle of 0° involves a combined tension-shear fracture. For dip angles of 0° and 60°, the crack propagation mechanism gradually shifts from tension-shear to tension failure, while at 90°, the crack propagation mechanism is primarily along the bedding plane in tension. The tensile failure characteristics of coal samples with bedding dip angles of 60° and 90° are more pronounced, and the load- acoustic emission parameter curve shows distinct bedding features. In the case of a 30° bedding dip angle, the failure is mainly due to a combined shear and tension cracking, with the acoustic emission counts exhibiting a multi-stage growth pattern. Furthermore, this study explores the implications of bedding coal fracture morphology for fracturing.

The possibility of reusing mesoporous Sibunit as an adsorbent for 2,4-dichlorophenoxyacetic acid was studied. The effectiveness of using microwave radiation to restore the adsorption properties of the studied adsorbent was shown. A decrease in the average pore size on the surface of the Sibunit sample was noted as the adsorption–regeneration cycles were carried out without reducing the value of the adsorption capacity.

The results of a study on the pyrolysis of agricultural (coffee husks and parchment) and agroindustrial (two types of spent coffee grounds) waste from coffee production are presented. A study of the temperature dependence of the weight loss of samples during pyrolysis and the qualitative analysis of the main volatile substances were carried out using a thermogravimetric analyzer (TG) coupled with a Fourier transform infrared spectrometer (FTIR). The main stages of thermal decomposition of the samples were presented at four heating rates of 5, 10, 20, and 30 K/min. The results of an analysis of IR spectra for the volatile components of pyrolysis products of four materials were shown, and the temperature dependences of the absorption band intensities of the main gaseous pyrolysis compounds were plotted.

In this work, a study of chicken litter pyrolysis was carried out in a thermal analyzer in a temperature range from 20 to 905°C at different heating rates of the raw material. Four peaks were obtained in a graph of the temperature dependence of the rate of weight loss. The first and second peaks were associated with the decomposition of plant biomass components; the third peak was due to the decomposition of plant and manure components, and the fourth peak characterized the decomposition of compounds from the mineral part of chicken manure. Spectral analysis of the gaseous products of chicken litter pyrolysis showed that they contained flammable components typical of gaseous products of thermal decomposition of plant biomass. The temperature range of the most intense formation of main carbon-containing compounds was 140–380°C. In addition, nitrogen-containing compounds associated with the decomposition of urea and proteins from chicken manure were found in the volatile components.

The results of thermogravimetric analysis of polyacrylonitrile fiber samples after the process of oxidative thermal stabilization in air are presented. Based on a study of a commercial sample of PAN fiber, the dependences of the weight loss of the starting material on the final temperature of oxidative thermal stabilization and the heating rate are presented. A machine learning model was built using the results of the experiments in order to predict the dependence of the weight loss of the starting material on the technological parameters of the oxidative thermal stabilization process.

Biomass energy is increasingly recognized as a promising alternative to conventional energy sources, offering potential sustainability and environmental benefits. Miscanthus has emerged as a standout candidate within energy crops, with M. lutarioriparius particularly noteworthy. This research delves into the intricate relationship between the timing of harvest and the resulting biomass yield and combustion quality of M. lutarioriparius in the unique coastal wetlands surrounding China’s Dongting Lake. An extensive field experiment was meticulously executed to explore these dynamics, yielding valuable insights comprehensively. (1) First and foremost, the study unearthed a paradoxical trend: delaying the harvest of M. lutarioriparius led to an increase in the stem-to-leaf ratio. However, this apparent benefit was counterbalanced by a noticeable decrease in overall biomass yield, primarily driven by the shedding of leaves as harvest was delayed. Delving into the intricacies of biomass composition, delayed harvests had a significant impact. (2) Specifically, they resulted in marked reductions in water content, ash content, and hemicellulose levels within M. lutarioriparius biomass. The correlation analysis further underscored the importance of cellulose and lignin, with a strong positive relationship between their content and calorific value, while hemicellulose exhibited a highly significant negative correlation. (3) Additionally, the study ventured into the realm of mineral elements within the biomass. Delayed harvesting precipitated a substantial reduction in their content, with notable fluctuations observed in potassium (K) and calcium (Ca) levels. Furthermore, ash content exhibited positive correlations with potassium (K) and silicon (Si) contents, shedding light on the intricate interplay of mineral elements. A notable silver lining emerged despite the reduced biomass yield associated with delayed harvesting. In a holistic assessment, the optimal window for harvesting M. lutarioriparius to maximize fuel quality was pinpointed to span from late November to the conclusion of January in the subsequent year. This nuanced understanding of harvesting timing can play a pivotal role in optimizing the utilization of M. lutarioriparius as a valuable energy resource.

The shallow-buried close-distance coal seam group has the characteristics of large mining height, shallow burial depth and small interlayer spacing. After coal seam mining, a penetrating air leakage channel is formed on the surface and underground, which is the main cause of low oxygen in the return air corner. This paper, PFC simulation is used to study the caving law of overburden rock and the evolution process of air leakage channel during the mining process of working face. The results show that the low oxygen gas in the goaf of 12 # coal seam mainly migrates to the return corner of the lower 221014 working face. The main medium facilitating this is the interconnected inter-coal seam air leakage channel, and the primary driving force is the substantial and rapid decrease in surface gas pressure, leading to a significant gas pressure difference between the return airway corner and the goaf of the 12 # coal seam. Aiming at the low oxygen phenomenon in the return air corner. The governance measures involving even-pressure ventilation technology were proposed. Theoretical calculations determined a safe gas pressure adjustment range for the return airway corner to be between 88.328 and 88.549 Pa. The pressure equalizing ventilation technology effectively controls the pressure difference between the goaf of 12 # coal seam and 22104 working face, and reduces the air leakage. Finally, the oxygen concentration in the return air corner is increased to prevent excessive fresh air from pouring into the goaf.

The article presents the results of experimental studies on the production of fuel briquettes from carbon-containing technogenic raw materials with a certain energy potential, flotation concentrate of coal enrichment sludge and wood and plant residues with binders. The technical characteristics of fuel briquettes of experimental batches are presented. The applicability of the selected binders for obtaining high-quality fuel briquettes was demonstrated. Aspects of the formation of the structure and properties of fuel briquettes are considered.

This study investigates the mineralogical composition and elemental distribution of oil shale and its ash from Sultani deposits using X-ray diffraction (XRD) and X-ray fluorescence (XRF) analyses, respectively. The XRD analysis of the oil shale samples confirmed the presence of calcite and quartz as primary mineral phases. However, XRD analysis of the oil shale ash revealed the presence of gypsum in addition to calcite and quartz, suggesting thermal decomposition and mineral transformation during combustion. The Sequential solvent extraction procedure provides insights into the distribution of heavy metals within Sultani oil shale ash. Specifically, the water-soluble fraction (stage 1) exhibited the presence of readily mobile metals, notably sulfur and silicon. In the exchangeable fraction (stage 2), metals were identified as bound to particle surfaces and acid-soluble salts, with notable concentrations of calcium, iron, and other trace elements observed. Manganese oxide and organically bound metals emerged in the easily reduced fraction (stage 3), while metals associated with oxidizable minerals were predominant in the oxidizable fraction (stage 4). Additionally, the non-mobile fraction (stage 5) entrapped metals within mineral crystal lattices, indicating limited mobility.

This work aimed to investigate the removal of sulfur compounds from light kerosene using activated carbon (AC) that was treated with alkali agents (KOH and NaOH) to enhance its adsorption properties. The physicochemical properties of the as-received AC and AC/alkali agents were characterized using Fourier transform infrared spectroscopy (FTIR). To evaluate the effectiveness of the surface modifications on the adsorbents, various operating conditions were examined. The agitation speed varied between 200, 300, and 400 rpm, while the contact time ranged from 15 to 35 minutes. Additionally, different percentages of KOH (5, 10, 15%) and NaOH (5, 10, 15%) were used to assess their influence on the removal efficiency of sulfur compounds. Based on the given information, it appears that the treatment of activated carbon (AC) with alkali agents, specifically KOH and NaOH, has resulted in an increase in the specific surface areas of the AC. This increase in surface area could potentially enhance the adsorption capabilities of the AC. The results showed that AC/KOH achieved a sulfur removal efficiency of 69%, while AC/NaOH demonstrated a higher efficiency of 84%. The highest sulfur removal efficiency was achieved under specific conditions: a NaOH concentration of 4 M, agitation speed of 400 rpm, and contact time of 35 minutes. Overall, the treatment of activated carbon with alkali agents, particularly NaOH, led to increased specific surface areas and the presence of hydroxyl functional groups. The surface area of AC-treatment will be increased because the functional group formation new location in AC-support and increased the porosity, therefore the surface area will increase. The resulting composites, AC/KOH and AC/NaOH, demonstrated enhanced sulfur removal efficiency compared to other composites, with AC/NaOH showing the highest performance.