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Coalbed methane (CBM) is the only unconventional gas in Poland with estimated recoverable resources. The prospects for developing deep CBM have been explored in recent years by drilling deep exploration wells within the depocenter of the Upper Silesian Coal Basin. The purpose of this study is to analyze the occurrence and potential for CBM extraction in this area of the basin, which can be considered prospective due to the confirmed presence of significant amounts of gas and thick coal seams at depths > 1500 m. The study examined the vertical and horizontal variability of the gas content in the studied area, the coal rank in the seams, thermal conditions, and coal reservoir parameters. The gas content in the seams, reaching more than 18 m3/t coaldaf at a depth of 2840 m, and indicative estimated gas resources of 9 billion m3 were found. The high gas content is accompanied by positive thermal and coal rank anomalies. The permeability and methane saturation of the coal seams are low, and therefore, potential methane production may prove problematic. However, the development of CBM extraction technologies involving directional drilling with artificial fracturing may encourage gas production testing in the study area. [ABSTRACT FROM AUTHOR]

This contribution presents the results of structural investigations on the cured and high temperatures of three series of geopolymers. The specimens were synthesized at 80 °C from coal fly ash and three activators of variable composition based on sodium hydroxide and sodium silicate solutions. Structural and microstructural analysis was performed, especially using in-situ measurements of XRD patterns and IR spectra as a function of temperature. The cured compounds' phase content and compressive strength changed slightly depending on the starting chemical composition. All analyzed materials experience a mass loss due to water removal at 300 °C, followed by increased porosity from disintegrating compounds above 300 °C. Higher alkali content improves strength (400–600 °C) possibly due to nepheline formation. The amorphous phase gradually softens during heating, influenced by alkali content. Structural analyses were supported by model calculations of a number of aluminosilicate structures. The cluster analysis using the k-means algorithm was used to divide the PCA space into regions that represent structural similarities, and analyzing specific point positions in the space allowed for several conclusions to be drawn about the studied materials, including that changes in chemical composition and thermal treatment can promote the transformation from sodalite to nepheline and that the glass network has elements that are nepheline-like and may promote its crystallization. [ABSTRACT FROM AUTHOR]

The work presents a detailed analysis of the possibilities of the thermal processing of clay raw material granulates in a fluidized bed reactor powered by coal fuel. Potential customers of calcined granulates include the following: plants producing refractory materials for the steel industry, producers of refractory concrete, sanitaryware plants, tile plants, large-size tile plants, industry abrasives, chemicals, paints, paper, food and medical industries and others. The advantage of the presented fluid bed calcination technology is the possibility of the continuous operation of the reactor and the short time of the material in the bed, compared to the previously used methods of calcination in a shaft and rotary kiln, which lasts less than twenty minutes in the temperature range of 650–850 °C. During the experimental studies of calcination in the fluidized bed layer, the influence of the type of coal, its particle size and the mass share of coal in the feed mixture on the calcination process and the final product obtained was analysed. As a result of the conducted research, it was proven that solid fuels such as anthracite and steam coal type 31.2 (flaming) can be successfully used in the fluidized bed calcination process of clay materials. The key parameter determining the fluidized bed calcination process is the fuel particle distribution. [ABSTRACT FROM AUTHOR]

Coal, extensively used in many countries across various industries, particularly as a fuel in the energy sector, poses significant environmental challenges due to process-related implications and their complex characteristics. A notable obstacle arises from its heterogeneous and complex submicron–nano-molecular structure, often leading to operational issues that are challenging to predict. This research aims to comprehensively assess the environmental impact of bituminous coal sourced from the Barapukuria Coal Mine (NW Bangladesh). This study focuses on elucidating the intrinsic properties of coal, with specific attention to its thermal behavior, structural composition, and surface morphology, aiming to understand the implications for energy production. Advanced techniques, such as TGA/DTG, CHNS-O, XRD, FTIR, XRF, ICP-OES, XPS, SEM with EDX, and TEM, were employed. Rigorous experimentation and analysis provided valuable insights into combustion and pyrolysis processes, illuminating the release of environmentally hazardous pollutants and their negative consequences associated with the utilization of Barapukuria coal for energy generation. Thermogravimetric analysis indicates coal bond breakdown at 573–933 K, releasing gases and liquids during the breakdown stage, resulting in mass loss from moisture evaporation, protogenic gas release, and volatile matter loss. Despite being of the bituminous type, the coal exhibits a mean carbon concentration of 78.24% and a low sulfur content of 0.42%, signifying relative environmental friendliness compared to high-sulfur coals, which is crucial for preventing acid rain. The average higher heating value (31.04 ± 0.74 MJ kg−1) and calorific value (30.20 ± 0.95 MJ kg−1) indicate that the studied coals have high energy potential. This study also suggests that optimizing thermochemical conversion for power generation may enhance energy efficiency and mitigate potential environmental impacts. The research findings contribute to the scientific understanding of coal thermal properties, serving as a foundation for informed decision-making in energy production strategies that prioritize both efficiency and environmental sustainability. [ABSTRACT FROM AUTHOR]

Rock cross-cut coal uncovering (RCCU) is susceptible to coal and gas outburst incidents, greatly impeding the safe extraction and miner safety. Freezing coal at low temperatures can enhance its mechanical properties and encourage gas adsorption. For the practical application of this method to prevent coal and gas outburst, water needs to be injected into the coal seam. However, the mutual dynamic response of the water–gas–coal combination during low-temperature freezing has not been sufficiently investigated, seriously restricting its application in disaster prevention. Therefore, this study investigates these characteristics using a low-temperature freezing experimental setup that was built for gas-bearing coal under conditions of water infiltration. The findings indicated that under low-gas-pressure conditions, the coal samples exhibited a larger degree of pore wettability. The improved Aronofsky index model was used to explain the relationship between the gas replacement quantity and time. Time required for the coal temperature to reach equilibrium showed a positive correlation with freezing temperature and gas pressure, respectively. As freezing temperature and gas pressure rise, respectively, freezing coal's thermal conductivity falls. The longitudinal strain of freezing coal rises with the drop in gas pressure and freezing temperature, respectively. Low-temperature freezing was conducive to the transformation of micropores and small pores into mesopores, macropores, and fractures. Based on these results, a collaborative measure of borehole methane drainage, coal seam water injection, and low freezing coal to prevent coal and gas outburst was proposed. The study lays a theoretical foundation for preventing coal and gas outbursts during RCCU. [ABSTRACT FROM AUTHOR]

This work presents the combustion behavior of different mean relative densities (MRD) of Indian thermal coal. Coal of different MRD in the range of 1.25 to 2.20 was prepared using the density separation method. Essential characterization of all MRD fraction coals was done by proximate analysis, ultimate analysis, gross calorific value, BET analysis, and ash analysis. The combustion behavior of all coal samples was carried out by a thermogravimetric analyzer (TGA). Combustion characteristics parameters such as ignition temperature (TIG), peak temperature (Tmax), burnout temperature (TBT) and maximum combustion rate (DTGmax) were evaluated using TGA-DTG data. Results show that with the increase of MRD from 1.25 to 2.20, TIG and Tmax increase from 324°C and 451°C to 426°C and 462°C, respectively, while DTGmax reduces from 9.52 to 1.68 mass%/min. The kinetic analysis demonstrates that coal combustion follows the first-order reaction model and can be separated into two stages. The thermodynamic parameters signify that lighter MRD coal requires lower endothermic energy than heavier MRD coal. [ABSTRACT FROM AUTHOR]

The laws of thermal degradation of the mixture of the heavy fraction of low-temperature coal tar and coal shale were investigated using dynamic thermogravimetry. The kinetic characteristics of the process were determined using various methods, including the Ozawa–Flynn-Wall, Friedman, non-parametric kinetics and Šesták–Berggren methods. It is shown that coal shale initiated changes in the kinetic parameters and decomposition rate of the heavy fraction of coal tar. It was found that a 13% content of coal shale in the mixture led to the maximum rate of weight loss of the heavy fraction of coal tar. A hydrodemetallization kinetic model of the mixture of the heavy fraction of low-temperature coal tar and coal shale is proposed. The kinetic parameters of the hydrodemetallization process were determined; in addition, the rate constants at various temperatures were estimated. The study shows that the distribution of trace elements in the hydrogenate from the initial mixture and in the hydrogenate from the solid residue was characterized by relatively low values of reaction rate constants. The maximum microelement distribution rate was achieved in the hydrogenate solid residue. Energy indicators of activation processes indicated that hydrodemetallization at low temperatures is advantageous from an energy point of view. [ABSTRACT FROM AUTHOR]

Magma intrusion has an important influence on the physical and mechanical properties of coal and rock. In the area of magma intrusion, disasters such as gas outburst are prone to occur. Revealing its invasion law will be conducive to disaster management and energy development. For this purpose, changes in industrial analysis components of coal, mineral composition, major oxides, trace elements, and rare earth elements of coal under the thermal metamorphism of magma intrusion were analyzed. It is found that the moisture and volatile matter contents of the thermally affected coals in the mining face are generally lower than that of normal coals, while moisture and volatile matter contents are reduced towards to the magma intrusion contact. For example, the moisture and volatile matter of coal sample M01 decreased by 64.6% and 38.6% respectively compared with coal sample M05. During magma intrusion, some minerals remain on the surface of the coal body, resulting in changes in the mineral composition of the coal body. The decrease in carbon atom net spacing, the increase in crystallite aggregation and ductility, and aromaticity in thermally affected coals have a positive impact on the improvement of coal metamorphism. Due to the influences of magmatic intrusion, the variation rules of major oxides in coal are different, and the closer to the magmatic intrusion zone, the easier the major oxides are to be depleted. However, magma intrusion will not lead to the loss of all major oxides in thermally affected coals, such as content of CaO is 54.8%, which is higher than that of coal not affected by magmatic hydrothermal fluid. Most of the trace elements in the thermally affected coals of the No. 9 coal seam are depleted. The contents of rare earth elements are low on the whole coalbasis, with an average of 29.48 μg/g, and the distribution pattern towards to magmatic intrusion shows a wide and gentle "V" curve with left high and right low, showing the characteristics of enrichment of light rare earth elements. [ABSTRACT FROM AUTHOR]

Coal fly ash (CF) is used in coal pyrolysis or gasification as a result of the high content of oxide metals. However, CaSO 4 and SiO 2 in CF inhibited catalytic activity. Herein, the application of acid-base modified CF to steam gasification of coal (CA). It was found that the order of acid-alkali modification had different effects on the H 2 production. NaOH–HF (A-E) modified CF, there was no CaSO 4 present on the surface of CF, and the surface SiO 2 shell structure was destroyed, releasing more α-Fe and α-Fe 2 O 3. A new Fe active phase (Fe x F y) had been formed. Meanwhile, the functional groups on the surface of modified CF changed, resulting in more C–H bonds, which provided more H sources for gasification. The α-Fe and α-Fe 2 O 3 in NaOH–HF modified CF were in full contact with coal and steam, breaking the O–H bonds in the H 2 O, the aliphatic side-chain hydrocarbons and C–H bonds in the coal to produce more H 2. α-Fe 2 O 3 and α-Fe undergoes mutual transformation at the action of H 2 , providing more Fe to increasing H 2 production. When the gasification temperature was 900 °C, the steam flow rate was 1 mL/min and the heating rate was 10 °C/min, the H 2 yield increased from 915.97 mL/g -(E-A) to 1539.72 mL/g -(A-E) , the carbon conversion of coal gasification was 99.68%. [Display omitted] • Release of catalytic activity of fly ash itself using NaOH–HF modification method. • The NaOH–HF modification method was used to reduce the content of CaSO 4 in CF. • The NaOH–HF modification method was used to change the original structure of the CF. • α-Fe and α-Fe 2 O 3 promotes the fracture of O–H bonds in H 2 O and C–H bonds in coal. • The modified fly ash enhances the generation of H 2 in coal under steam. [ABSTRACT FROM AUTHOR]

Thermal power plants are pivotal in meeting global energy demands, yet enhancing their efficiency and sustainability remains an enduring challenge. While previous studies have scrutinized energy and exergy analyses of distinct plant components, there's a scarcity of comprehensive reviews integrating findings across diverse plant types. This paper bridges this gap by presenting a comprehensive synthesis of recent advancements in energy and exergy studies across coal, gas, biomass, oil, and combined cycle plants. The review focuses on critical aspects: optimizing operations through modeling and advanced controls, economic evaluations encompassing costs and revenue, and assessing environmental impacts such as emissions and water use. Achieving a balance between performance, cost-effectiveness, and environmental responsibility is crucial for sustainable thermal power generation worldwide. It requires an integrated approach that considers technical, economic, and environmental factors to ensure efficiency, profitability, and minimal adverse effects on health and climate. Key findings emphasize that, in most cases, the boiler emerges as the primary source of exergy destruction, accounting for over 50% of losses across varied plant configurations. Turbines and condensers also significantly contribute to energy losses. Supercritical and ultra-supercritical power plants exhibit higher efficiencies compared to subcritical counterparts. Integrating waste-to-energy technologies with coal plants holds promise, offering efficiency improvements and reduced environmental impact. Optimizing parameters such as pressure and temperature, along with component advancements, shows potential in curbing losses. These optimization endeavors have showcased a notable up to 6% enhancement in exergy efficiency. This review underscores the critical role of ongoing thermodynamic modeling and assessments in steering towards more sustainable thermal power generation. In summary, this paper delivers valuable insights into performance benchmarks and delineates effective strategies for augmenting thermal power plant efficiency through exhaustive energy and exergy analyses. [Display omitted] • Exergy analysis provides a broader perspective than energy analysis alone. • Boiler subsystem is a major source of exergy destruction (52-85% of total losses). • Supercritical and ultra-supercritical plants display higher efficiencies than subcritical ones. • Optimization of parameters like temperature and pressure can boost exergy efficiency by up to 6%. • Advanced combined cycles achieved over 50% efficiency, indicating potential for lower CO2/kWh. [ABSTRACT FROM AUTHOR]

Heavy metals such as Lead(II), Nickel(II), Manganese(II), Cadmium(II), Chromium(VI), etc., are leached from the coal ash of thermal power plants. These metals contaminate ash pond water and subsequently contaminate groundwater. Phycoremediation using microalgae/cyanobacteria is an emerging technology for removal of heavy metals. The present study aims at phycoremediation of the said heavy metals from ash pond water using cyanobacterial consortium of Limnococcus limneticus and Leptolyngbya subtilis followed by the development of an accurate data-driven Multigene Genetic Programing (MGGP) approach for modeling and optimization of the process. The developed model was used to obtain a correlation between the average removal of metals and biomass production with all input factors such as the initial metal concentrations, pH, and days of incubation. To maximize metal removal and biomass production, the Water Evaporation Optimization (WEO) technique was applied to determine optimal values of input parameters. The application of WEO for the optimization of the phycoremediation process is the first of its kind and here lies the novelty of the study. [ABSTRACT FROM AUTHOR]

The Permian Longtan Formation in the Songzao coalfield, Southwest China, has abundant coalbed methane (CBM) stored in high-rank coals. However, few studies have been performed on the mechanism underlying the differences in CBM gas content in high-rank coal. This study focuses on the characterization of coal geochemical, reservoir physical, and gas-bearing properties in the coal seams M6, M7, M8, and M12 based on the CBM wells and coal exploration boreholes, discusses the effects of depositional environment, tectono-thermal evolution, and regional geological structure associated with CBM, and identifies major geological constraints on the gas-bearing properties in high-rank coal. The results show that high-rank coals are characterized by high TOC contents (31.49~51.32 wt%), high Tmax and R0 values (averaging 539 °C and 2.17%), low HI values (averaging 15.21 mg of HC/g TOC), high porosity and low permeability, and high gas-bearing contents, indicating a post-thermal maturity and a good CBM production potential. Changes in the shallow bay–tidal flat–lagoon environment triggered coal formation and provided the material basis for CBM generation. Multistage tectono-thermal evolution caused by the Emeishan mantle plume activity guaranteed the temperature and time for overmaturation and thermal metamorphism and added massive pyrolytic CBM, which improved the gas production potential. Good geological structural conditions, like enclosed fold regions, were shown to directly control CBM accumulation. [ABSTRACT FROM AUTHOR]

Pond ash is a byproduct obtained from the combustion of coal in thermal power plants. It can be used as an alternative to conventional granular materials in compacted subgrade or subbase layers in pavements. The properties can be further enhanced by the addition of small doses of cement. Typically, the modulus parameters required for the design of pavements are based on resilient modulus models. Such models presume that the material attains a shakedown response in every loading sequence and the resilient modulus (MR) can be defined. However, it is not very clear whether a nonconventional material such as pond ash or cemented pond ash attains shakedown within 100 cycles of each sequence as stipulated in the resilient modulus test protocol. The number of loading cycles required to reach the shakedown limit is explored in this study. There are two sets of experiments conducted: the conventional resilient modulus tests with 100 cycles in each sequence and repeated load triaxial tests with 10,000 cycles for three confining pressures (41.4, 27.6, and 13.8 kPa) at a deviator stress of 69 kPa. The effect of cement dosage (2% and 3%), compaction condition (standard and modified Proctor compaction), and water content (optimum moisture content (OMC), OMC−2%, and OMC+2%) were studied. The shakedown theory is explained in terms of permanent deformation increment per cycle, dissipated energy, and tangent modulus. The resilient modulus is defined as the tangent modulus of the material which has attained shakedown. The cemented pond ash did not strongly correlate to confining pressure and hence, a constant value of the resilient modulus may be used. [ABSTRACT FROM AUTHOR]

A wide range of wastes can potentially be used to generate thermal and electrical energy. The co-combustion of several types of waste as part of water-containing waste-derived fuels is a promising method for their recovery. In this research, we use thermogravimetric analysis and differential scanning calorimetry to study the thermal behavior and kinetics of coal slime, biomass, waste oils, and blends on their basis. We also analyze the concentrations of gaseous emissions. The results show that biomass, oils, and coal slime significantly affect each other in the course of their co-combustion when added to slurry fuels. The preparation of coal-water slurry based on slime and water reduced the ignition and burnout temperature by up to 16%. Adding biomass and waste oils additionally stimulated the slurry ignition and burnout, which occurred at lower temperatures. Relative to dry coal slime, threshold ignition temperatures and burnout temperatures decreased by 6%–9% and 17%–25%, respectively. Also, the use of biomass and waste oils as part of slurries inhibited NO х and SO 2 emission by 2.75 times. According to the kinetic analysis, added biomass and waste turbine oil provide a 28%–51% reduction in the activation energy as compared to a coal-water slurry without additives. [Display omitted] [ABSTRACT FROM AUTHOR]

As relict features of coal mines, carbonaceous spoil, waste and tailing dumps remain susceptible to coal oxidation and thermal decomposition, together with spontaneous combustion. Modern methods for monitoring surface thermal signatures regularly include the use of UAV's, equipped with suitably sensitive infrared cameras. Detection of sub-surface thermal anomalism includes Vegetation Index Monitoring and/or the use of in-ground probes. Research across thermally active tailings offers insights into how best apply these two techniques, and increasingly the required scheduling of UAV surveys. [ABSTRACT FROM AUTHOR]

Flip-flow vibrating screens (FFVSs) effectively tackle the challenges posed by the dry deep-screening of wet, fine, low-grade bituminous coal, thereby facilitating advancements in the thermal coal preparation process. The tensile lengths of the screen panels not only influence the service lives of the screen panels but also play a pivotal role in determining the screening performance of the FFVSs. To investigate the effect of the screen-panel tensile length on the screening performance of an FFVS, this study constructs a dual-mass flip-flow screening test rig. The experimental results reveal that when the fine-particle content and the external water content in the feed of low-grade bituminous coal are 55% and 16%, respectively, the most favorable tensile length of the screen panels is 2 mm. With a fine-particle content of 55% in the feed of low-grade bituminous coal and an increase in the external water content from 4% to 20%, the screening efficiency of the FFVS initially decreases and then increases. Notably, low-grade bituminous coal with 16% external water content poses the most challenging screening conditions. Furthermore, when the external water content of the low-grade bituminous coal is 16% and the fine-particle content in the feed increases from 25% to 55%, the screening efficiency of the FFVS gradually improves. [ABSTRACT FROM AUTHOR]

Coal mining is known for its contributions to climate change, but its impacts on the environment and human lives near mine sites are less widely recognised. This study integrates remote sensing, GIS, stakeholder interviews and extensive review of provincial data and documents to identify patterns of infringement, risk and impact driven by coal mining expansion across East Kalimantan, Indonesia. Specifically, we map and analyse patterns of mining concessions, land clearing, water cover, human settlement, and safety risks, and link them with mining governance and regulatory infractions related to coal mining permits. We show that excessive, improper permit granting and insufficient monitoring and oversight have led to deforestation, widespread overlaps of concessions with settlements, extensive boundary and regulatory violations, lacking reclamation, and numerous deaths. As the world's largest thermal coal exporter, Indonesia's elevated coal infringements, risks, and impacts translate to supply chain, sustainability, and human rights concerns for global coal markets. [ABSTRACT FROM AUTHOR]

The study deals with the possibilities of using alternative types of fuels to produce electricity. Power Plant Vojany (PPV) is a thermal power plant (TPP) in eastern Slovakia, which is part of the company Slovenské elektrárne, a. s. (SE). PPV primarily used black coal to produce electricity, which had to be imported from abroad (the Russian Federation). This activity has become inefficient both economically and environmentally, due to the high price of CO2 permits and the high emission factor of this type of fuel. PPV decided to co-combust biomass and refuse-derived fuel (RDF), which resulted in much better economic conditions due to their price, economic efficiency, and partly closed CO2 cycle. The aim of the paper is to explore the possibilities related to the production of energy in the cleanest possible way and with the least possible damage to the environment in coal thermal power plants using the example of operating Power Plant Vojany located in eastern part of Slovakia and to inspire each other for the modern transformation. For the purposes of hypothesis verification, analytical methods focused on overview studies of average fuel prices, comparisons, and the balance of fuels in connection with eliminated CO2 emissions, as well as municipal waste (MW) management in the EU and V4 countries, were used. The authors also focused on the energy recovery and combustion of MW and tracking the achieved CO2 savings in connection with the development of fuel sources in PPV. The results point to the fact that PPV is one of the power plants that could use biomass and RDF as fuel, which confirms the economic advantages of this procedure. The results confirm that the potential of RDF production in Slovakia is sufficient to ensure the operation of PPV at planned, even higher volumes of electricity production. The transformation to cleaner operation of coal thermal power plants represents a significant contribution of this study. [ABSTRACT FROM AUTHOR]

To reach the worldwide decarbonisation and the corresponding climate change mitigation, low-carbon energy sources must be used in the near-term and the role of the nuclear energy in pathways to produce net zero emissions is outstanding. This is not only because nuclear energy produces carbon-free energy, but also because it can supply high-temperature process heat to industrial applications such as the hydrogen production. Hydrogen is presently considered as the energy vector of the future to attain these environmental goals. In this paper, the possible use of a nuclear-assisted steam coal gasification process for hydrogen production is investigated in deep. As a modern High Temperature Gas Cooled Reactor (HTGR) is able to produce a gas outlet temperature of 950 °C, the nuclear heat can be transferred to a steam coal gasification plant via an intermediate helium circuit for providing the high-temperature process heat required by the endothermic gasification reactions between the steam and the carbonaceous matter. The nuclear-assisted gasification technology is considered to be attractive for the processing of an Argentine orthoasphaltite that is extracted from a minefield located in Neuquén province. The present research comprises both theoretical and experimental studies, which were addressed to get the necessary information about the optimal conditions for the hydrogen production though the steam gasification process using the Argentine orthoasphaltite as feedstock. A conceptual design of an energy complex for nuclear hydrogen, electricity and liquid fuels production is also proposed. In this conceptual design, the steam coal gasification reactor consists of two concentric vessels specially designed to separate the pyrolysis step occurring at low temperature and the char gasification step that takes place at higher temperatures. In this way, it is possible to give a full use to the volatile compounds that are present in the feedstock and are identified and characterized in this work. [Display omitted] • Thermodynamically-favourable conditions for H 2 production though steam gasification of carbonaceous matter were determined. • The use of a HTGR for providing the nuclear process heat for indirect heating of the gasification reactor was considered. • A technical feasibility analysis for processing an Argentine orthoasfaltite for nuclear hydrogen production was presented. • Operating conditions in the steam gasification process for producing a hydrogen-rich synthesis gas were optimized. • A dual-concept for the gasification reactor by separating pyrolysis and gasification steps was proposed. [ABSTRACT FROM AUTHOR]

The paper discusses the threat of decommissioning to the thermal power plant (TPP) heat exchanger tubes because of erosion and develops a computer-integrated control system (CICS) for the process of distribution of steam coal flows with different indicators of abrasive materials content, which is based on fuzzy logic. The problem of rapid decommissioning of TPP heat exchangers, particularly abrasive damage to furnace screen tubes, economizer, superheater, etc. This may indicate a discrepancy between the expected fuel ash content and the actual one, as well as a high content of abrasive impurities in steam coal. The work aims to develop a CICS of the wear resistance of the heat exchange surface of a steam boiler of a coal-fired power plant by measuring and fuzzy control of the content of abrasive impurities in steam coal. The problems of damage to the equipment of the TPP boiler are investigated, and a system for controlling the wear resistance of the surface by automatic fuzzy control of the quality of coal is developed. The results were investigated during coal preparation and combustion in the furnace of a thermal power plant to investigate the effectiveness of the proposed fuzzy controller. The model results confirm the feasibility of the fuzzy control method for the system with different coal quality parameters. [ABSTRACT FROM AUTHOR]

Power generation comprises high environmental and ecological impacts. The global power industry is under pressure to develop more efficient ways to operate and reduce the impacts of inherent process variability. With the rapid development of technologies within the energy sector, large volumes of data are available due to in-time operational measurements. With increased computer processing capabilities, machine learning is applied to explore these in-time operational measurements for improved process understanding. This research paper investigates machine learning algorithms for energy efficiency improvement at coal-fired thermal power plants by conducting a systematic literature review. This research is essential since it provides guidelines for applying machine learning towards sustainable energy supply and improved decision-making. Subsequently, efficient processes result in the reduction of fuel usage, which results in lower emission levels for equivalent power generation capacity. Furthermore, this study contributes towards future research by providing valuable insights from academic and industry-related studies. [ABSTRACT FROM AUTHOR]

Ash and slag waste (ASW) from coal combustion creates significant environmental and economic challenges. A promising method of ASW recycling is alkali activation with geopolymer material formation. This study investigates the influence of activating solution components (sodium hydroxide and sodium silicate) on the formation of porous geopolymers using ASW of different origins. The sodium hydroxide content of 0–4 wt.% and the sodium silicate content of 17–25 wt.% were studied. An increase in sodium hydroxide resulted in decreased density, but it adversely affected the strength. An increase in sodium silicate led to a compromised porous structure with relatively high density and compressive strength. An optimal composition, S19N3, comprising 3 wt.% of sodium hydroxide and 19 wt.% of sodium silicate obtained porous geopolymers with uniformly distributed 1.4–2 mm pores and a corresponding density of 335 kg/m3, a compressive strength of 0.55 MPa, a porosity value of 85.6%, and a thermal conductivity value of 0.075 W/(m·K). A mechanism for porous geopolymer formation was developed, including the interaction of alkaline components with ASW and a foaming agent, foaming, curing, and densification. The mechanism was examined using ASW from the Severodvinsk CHPP-1. This study allows for the optimization of geopolymer mixtures with various waste sources and the utilization of waste materials in the construction industry. [ABSTRACT FROM AUTHOR]

The spontaneous combustion period of coal in deep mines is short, so the risk of coal spontaneous combustion (CSC) is high, and it is cause environmental pollution. To explore the relationships between the microstructure and thermal effect of coal in deep mine, the relation among microstructure, activation energy and thermal effect of CSC was analysed using differential scanning calorimetry, Fourier infrared spectroscopy and synchronous thermal analyser, respectively. Results show that the process of coal self-combustion can be divided into 3 stages: the slow oxidation stage, accelerated oxidation stage and rapid combustion stage. In the slow oxidation stage, the XJL coal sample experienced the largest thermal release, and the main functional group was C–H–. In the accelerated oxidation and rapid combustion stages, the ZL coal experienced the largest thermal release; the functional groups are mainly C=C, –CH3, –CH2. In simpler terms, aromatic hydrocarbon significantly impacts the heating process of TK coal combustion. The structure of these hydrocarbons shows the highest correlation with the thermal release, followed by oxygen-containing functional groups for gas coal. These findings can help manage the risks of CSC and prevent potential dangers. [ABSTRACT FROM AUTHOR]

The new process 'coal gangue/fly ash – HNO 3 pressure leaching (NAPL) –low-temperature pyrolysis' was proposed by our team, which aimed to achieve the transformation of coal-based solid wastes from harmless to Al resource. For cost control, the regeneration of HNO 3 at a low cost was crucial for the process. Following NAPL of coal gangue and fly ash, massive amounts of Al(NO 3) 3 ·9 H 2 O were collected, with a decomposition temperature as low as 523 K. The energy consumption for low-temperature pyrolysis could be supplied by the combustion of residual carbon (6.96 wt%) during the thermal activity of coal gangue, allowing HNO 3 to be regenerated and recycled without extra heat supply. However, little research has been done on the pyrolysis behavior and kinetics of Al(NO 3) 3 ·9 H 2 O, which was examined in this study. The pyrolysis characteristics of Al(NO 3) 3 ·9 H 2 O were assessed by TG-DSC analysis. Further experiments and XRD/FTIR/MS analysis revealed that phase evolution of Al(NO 3) 3 ·9 H 2 O followed the sequence of Al(NO 3) 3 ·9 H 2 O→ Al(NO 3) 3 ·nH 2 O→ Al(NO 3) 3 ·3Al(OH) 3 ·5/2 H 2 O→ AlOOH→ Al 2 O 3. Subsequently, the thermodynamic (∆ G , ∆ H , ∆ S) and kinetic (E a , A) parameters were calculated based on the thermogravimetric data by the iso-conversional methods. And the mechanism models and functions were identified via the Malek method. Finally, the economic evaluation of pyrolysis indicated that 5.04 × 10–3 Nm3 of natural gas was consumed during pyrolysis of one mole Al(NO 3) 3 ·9 H 2 O, equivalent to 44.33 $ per ton of Al 2 O 3. As a basic research of Al(NO 3) 3 ·9 H 2 O pyrolysis, this paper enhances related theories of the NAPL process. [Display omitted] [ABSTRACT FROM AUTHOR]

Coal spontaneous combustion is determined by a variety of factors. Testing can describe the changes incoal spontaneous combustion with various factors, however, the dependence of spontaneous combustion on various factors is unclear. Therefore, reliability theory was used to deduce the functional relationship of the dependence of coal spontaneous combustion on various factors, and construct a model algorithm for predicting the probability of occurrence of coal spontaneous combustion, which is adopted to evaluate and rank the degree of influence of various factors on coal spontaneous combustion. Effective prevention methods are proposed by strengthening the role of the most important factors. The results show that, by taking the duration of coal heating to 150°C as the measurement standard of coal spontaneous combustion, the duration of the initial stage of coal heating increases linearly with the increase of specific heat capacity, thermal conductivity, and moisture content of coal. With the increase of oxygen concentration, oxidation rate, and initial temperature of the coal, the duration of the initial stage of coal heating decreases exponentially. With the increase of gas flow seepage velocity in the coal body, the duration of the initial heating stage changes in a parabolic manner. At the same time, the probability of spontaneous combustion decreases exponentially with the increase of specific heat capacity and moisture content of the coal. The probability of coal spontaneous combustion increases linearly with the increase of coal thermal conductivity, oxygen concentration, gas seepage velocity, and rate of oxidation. The dependence of coal spontaneous combustion probability on different factors can be expressed as follows: coal temperature > gas seepage velocity > specific heat capacity > oxidation rate > oxygen concentration > moisture content > thermal conductivity. [ABSTRACT FROM AUTHOR]

One of the global state tasks, contributing to the implementation of the goal of developing the energy sector of the Russian Federation and given in the Energy Strategy of the Russian Federation for the period until 2035, is to reduce the negative impact of the fuel and energy complex industries on the environment. In this regard, special attention is paid to the coal ash handling problem, which is intensified by tightening of the environmental legislation with the transition to the principles of the best available technologies, greening of the coal power, depletion of the capacity of the coal ash disposal sites, etc. Disposal of ash, slag, ash-and-slag mixtures, formed at combustion of coal, peat and shale, is one of the main problems of the modern solid-fuel thermal power plants in Russia, the number of which makes 172. The average age of the coal-fired TPPs is about 50 years that significantly affects the technical and environmental performance of the ash removal system of TPPs. At the Russian TPPs for the ash and slag conveying hydraulic ash removal systems are the most common, used in the vast majority of cases being technically outdated, uneconomical and ecologically not friendly. Annually 25 ... 30 million tons of ash and slag are formed at the coal-fired power plants of the Russian Federation. Currently more than 1.5 billion tons of ash and slag are accumulated at the ash disposal sites of thermal power plants, and every year these figures are growing. About 2/3 of all ash and slag disposals are close to the design filling or are already overfilled. Elimination of objects of the accumulated environmental damage, representing ash disposals of the coal-fired power plants, is one of the conditions for Russia's transition to the standards of "green" economy. The problem of coal-fired power plants in terms of elimination of the accumulated environmental damage can be solved only by implementing the large-scale projects of integrated coal ash processing, obtaining required products. The article provides statistical data for the 2019 relating to the volumes of the coal ash generation and utilization in various countries of the world. An overview of the various applications of the coal combustion by-products, the main of which are ash and slag, in Russia, India, China, EU countries, etc. is presented. The article contains data on the applicability of the coal ash for various technologies of its use according to the Russian Ministry of Energy. A review of scientific and technical information sources on the prospects of using coal ash in hydrogen power engineering for hydrogen sorption and storage is given, as well as a review of traditional methods of hydrogen storage. Terminology in the field of coal ash handling found in scientific and technical information sources is considered, and a classification of coal combustion by-products in Russia and abroad is given. The main recommendations of the author, contributing to the increase in the use of coal ash in Russia, are given. [ABSTRACT FROM AUTHOR]

The aim of the work is to study the structure, phase composition and wear resistance of a steel 20Cr13 surface layer after microarc carburizing. Experiments are conducted with a surface current density of 0.45, 0.49 and 0.53 A/cm2. Electric current in the circuit: 2.5, 2.75 and 3.0 A. Impregnated surface temperature: 930, 1100 and 1250°C, respectively. Microarc saturation duration is varied in the range from 2 to 8 minutes in increments of 2 minutes. During steel 20Cr13 microarc carburizing a weakly etching surface layer of a carbide type with microhardness of 10.5–12.5 GPa is formed. The greatest layer thickness (18–20 microns) is achieved with a current density of 0.53 A/cm2 and the impregnation process duration is more than 6 minutes. Next is a zone with a very fine eutectoid structure of increased etching capacity about 300 microns thick with microhardness of 6.0–6.5 GPa, and then the initial structure with microhardness of 5.3–5.8 GPa. The result obtained is explained by the fact that during thermal decomposition of coal powder in which the processed product is immersed, carbon monoxide is formed, and upon contact with the surface of the sample atomic carbon is formed, which is adsorbed and diffuses into a saturated surface. Some of the carbon atoms under microarc discharge action undergo ionization, and the resulting ions are also able to diffuse into the steel surface. This significantly accelerates the diffusion process compared with traditional carburizing methods. At the same time, there is counter diffusion of atomic chromium from the steel composition towards the surface. Therefore, intense formation of chromium carbide begins at the saturated product surface. The process of carbide formation ends with formation of a surface zone consisting of chromium and iron carbides. Subsequently, there is an extended zone of very fine eutectoid mixture with increased etching capacity, formed as a result of a reduction in underlayer chromium content. Wear resistance tests are performed. Wear of samples made of steel 20Cr13 after microarc carburizing with a current density of 0.53 A/cm2 for 6 minutes followed by standard heat treatment is 1.34 times less than wear of samples made of this steel after a similar heat treatment without carburizing. [ABSTRACT FROM AUTHOR]

The aim of this paper is to provide a comprehensive overview of how electricity is produced from different sources and the electricity needs of the consumer. According to the Green Deal pact, the objective is to gradually reduce polluting emissions in the energy sector by 2050. In the meantime, the CO2 intensive thermal power plants (those using coal and heavy oil) will be closed and strategic investments in green energy sources will be pursued. This paper presents a detailed analysis of the profile of the Romanian electricity producer over a period of one year. Furthermore, this paper explores the possibility for the energy producer to adapt to consumer demand to reduce electricity imports, strategic locations for the installation of farms using renewable energy, and the current capacity of the national distribution system. This paper analyses electricity only quantitatively and not qualitatively, as well as the way the supplier follows consumers' need. The paper concludes on possible problems that may arise from the case of green energy. [ABSTRACT FROM AUTHOR]

Tons of fly ash are released every year due to the coal burned in thermal power plants that meet 80% of Türkiye's electrical energy needs. Especially considering the low-quality lignite reserves in Türkiye, the recycling rate of the high sulfate fly ash is relatively low. In concrete production, the use of ash containing high SO3 is not allowed due to the limitation of SO3 ratios of fly ash by regulations. Herein, the usability of fly ash, which has a high sulfate content due to the low-quality lignite reserves in Türkiye, and is therefore wholly waste, as a clinker replacement material was investigated. Fly ash, which has been used as a clinker replacement material, was obtained from Afşin Elbistan thermal power plant. Binders were obtained by grinding together the high sulfate fly ash, clinker and gypsum at different rates. The setting times of the mixtures in the fresh cement paste were determined, and the compressive strengths of the hardened samples were examined. As a result of the study, it was concluded that although the high sulfate fly ash extended the setting time by approximately 29% compared to the reference specimen, it increased the 28-day compressive strength of the hardened specimens up to 14%. [ABSTRACT FROM AUTHOR]

The pollution of upper soil horizons in the city of Gusinoozersk (the Republic of Buryatia) under the influence of emissions from the State District Power Plant (SDPP) working on brown coal from the Okino-Klyuchevskii deposit was studied. The contents of 14 elements (Sr, As, Co, Mo, Sb, V, Cu, Ni, Cr, W, Zn, Bi, Cd, and Pb) in bulk soil samples, as well as in the fraction of physical clay (particles with a diameter <10 µm, PM10) and in samples of brown coal and ash from the SDPP were determined. Priority pollutants of local soils (Urbic Technosols) are Sr, As, Co, Mo, Sb, and V; these elements tend to have higher concentrations in the PM10 fraction. The most contaminated area is the industrial zone of the city, where Sr, As, Co, V, Cu, Mo, Ni, and Cr contained in the fly ash of the Gusinoozersk SDPP tend to accumulate. A larger part of the territory (57% for bulk soils and 47% for the PM10 fraction) is characterized by a low level of pollution (Zc = 8–16). Arsenic poses the greatest environmental hazard; in the PM10 fraction, its concentrations exceed the maximum permissible concentration in 90% of the studied samples. The main factors controlling the accumulation of elements in soils and their PM10 fraction are the contents of iron and manganese oxides and organic matter, soil texture, acid–base conditions, and the location of sampling sites in the particular land use zones; these factors specify the formation of various classes of geochemical barriers. The polluting effect of brown coals depends on the contents of heavy metals and metalloids in them. A comparison of the chemical composition of the Okino-Klyuchevskii brown coal and fly ash from the Gusinoozersk SDPP with the Kansk–Achinsk coal and fly ash from the Central Thermal Power Plant (CTPP) of Severobaikal'sk indicates that the brown coal and ash from Severobaikal'sk are only slightly enriched in metals and metalloids, which significantly reduces their accumulations in soils. [ABSTRACT FROM AUTHOR]

Research on finding the trace element in the fly ash material becomes imposing due to environmental effect. Coal fly ash formed from the burning of coal by thermal power plants are huge and it has been a big problem in its disposal. The main aim of this study is geochemistry of fly ash sample from Neyveli thermal power station. Mine-I has a reserve of 365 MT and covers an area of 26.69 sq. km. The tiny mine-IA, which has a reserve of 120 MT, is spread across an area of 11.6 sq. km. The Indian government has approved the expansion of the second Mine's capacity from 4.7 MT to 10.5 MT. Despite the above listed numerous studies, the behavior of trace elements are still incompletely understood and additional investigations are required. The current study is a thorough examination of trace elements in Neyveli lignite combustion bottom ash and pond ash. In the bottom ash and pond ash, the concentrations of 21 elements (As, Ba, Cr, Ag, Cd, Co, Cu, Fe, Hg, Mn, Mo, Ni, Pb, Rb, Sr, Se, Ti, Zn, Zr, Sb, and Sn) were determined. [ABSTRACT FROM AUTHOR]

Rapid and stable analysis of coal quality for fine management of coal is essential for the clean and efficient utilization of coal in thermal power plants. In this work, a software-controlled coal analyzer with laser-induced breakdown spectroscopy (LIBS) coupled with X-ray fluorescence spectroscopy (XRF) was developed, which includes an LIBS analysis module, XRF analysis module, sample feeding module, control module and operating software. The instrument not only plays to the strengths of LIBS in multi-element analysis, but also inherits the advantages of XRF in high stability analysis, so that it can be used in power plants for rapid and continuous quality analysis of coal tablets. Based on chemometric regression methods using principal component analysis (PCA) and partial least squares regression (PLS), as well as the spectra of hundreds of coal samples, quantitative prediction models were established, and the industrial test and performance evaluation of the instrument were completed in the Shanxi Yangguang Power Plant in China. The experimental results showed that the R2 of the prediction models for calorific value, ash, volatiles and sulfur were 0.973, 0.986, 0.977 and 0.979, respectively, the RMSEs were 0.26 MJ kg−1, 0.68%, 0.33% and 0.13%, respectively, the RMSEPs were 0.62 MJ kg−1, 1.46%, 0.23% and 0.19%, respectively, and the average SDs were 0.11 MJ kg−1, 0.49%, 0.15% and 0.09%, respectively. The models showed good accuracy and stability, and the repeatability of the measurements of coal quality all met the requirements of national standards, and thus, could meet the needs of power plants. This work provides a new idea for the increasingly mature application of LIBS in coal analysis in various industrial sites. [ABSTRACT FROM AUTHOR]

To effectively separate 3–13 mm steam coal, new separation equipment which was a heavy-medium separation column was designed and tested in this study. Particles were measured to analyze the changes in the axial medium force of particles in the medium by employing the force measuring system. The influence of the medium flow rate (q), medium density (ρ), separation column height (h), and feed volume (g) on the separation effect was investigated by using the control variable method to establish the optimum separation condition. Under the optimum separation condition, the yield and the ash content of the clean coal were 74.05% and 16.18%, respectively. Based on the single factor study, the Box-Behnken response surface methodology (BBRSM) was used to investigate the influence of each interaction factor on the separation effect. The significance of each factor on the quantitative efficiency was in the order of ρ > q > h. Through the regression analysis, the mathematical model for the relationship between the quantitative efficiency and the separation parameters was established. The predicted quantitative efficiency and experimental quantitative efficiency were 87.88% and 89.32%, respectively. The difference between them was small, verifying the high accuracy and reliability of the prediction results of the regression equation model. [ABSTRACT FROM AUTHOR]

Steam coal is the blood of China industry. Forecasting steam coal prices accurately and reliably is of great significance to the stable development of China's economy. For the predictive model of existing steam coal prices, it is difficult to dig the law of nonlinearity of power coal price data and with poor stability. To address the problems that steam coal price features are highly nonlinear and models lack robustness, Laplacian kernel–log hyperbolic loss–Ridge regression (LK-LC-Ridge-Ensemble) model is proposed, which uses ensemble learning model for steam coal price prediction. First, in each sliding window, two kinds of correlation coefficient are employed to identify the optimal time interval, while the optimal feature set is selected to reduce the data dimension. Second, the Laplace kernel functions are adopted for constructing kernel Ridge regression (LK-Ridge), which boosts the capacity to learn nonlinear laws; the logarithmic loss function is introduced to form the LK-LC-Ridge to enhance the robustness. Finally, the prediction results of each single regression models are utilized to build a results matrix that is input into the meta-model SVR for ensemble learning, which further develops the model performance. Empirical results from three typical steam coal price datasets indicate that the proposed ensemble strategy is reliable for the model performance enhancement. Furthermore, the proposed model outperforms all single primitive models including accuracy of prediction results and robustness of model. Grouping cross-comparison between the different models suggests that the proposed ensemble model is more accurate and robust for steam coal price forecasting. [ABSTRACT FROM AUTHOR]

As an important unconventional oil and gas resource, the exploration and development of coalbed methane has attracted more and more attention. Since coalbed methane mainly exists in adsorbed state, it is important to study the pore space characteristics of coal for the analysis and prediction of coalbed methane content. Thus, in order to explore the evolutional characteristics of reservoir space during the thermal evolution of coal measure source rocks, two series of pyrolysis experiments as well as their corresponding pore structures were conducted. As the temperature and water pressure were the main factors to their organic matter and pores evolution, so temperature (250°C, 300°C, 350°C, 375°C, 400°C, 450°C and 500°C) and water pressure (10 MPa, 20 MPa, 30 MPa, 40 MPa, 50 MPa and 60 MPa) controlled experiments were analyzed. The experimental results show that temperature is positive to the organic matter evolution, and then in further promoted the development of pore structure. Namely, with the increasing thermal maturity, their corresponding pore volume, specific surface area as well as the numbers of macro-pores and micro-pores also gradually increased. But with the increasing water pressure, the pyrolysis productions did not changed obviously as well as their pore structures. It should be the reason of little effect of water pressure on organic matter evolution. Thus, the influence of water pressure on the development of pore structure is not significant compared with the variable temperatures, which has great influence on both liquid and gaseous hydrocarbons. Therefore, this study was helpful to the establishment of the linear equations on temperature and water pressure to the pore structures, which would be in further provide theoretical basis and guidance to the exploration and development of coals. [ABSTRACT FROM AUTHOR]

The world over energy resources are getting scarcer and increasingly exorbitant with time. In India bridging the ever- widening gap between energy demand and supply by increasing supply is an expensive option. The share of energy costs in total production costs can, therefore improve profit levels in all the industries. Thermal Power Plant is a major source of electricity production by coal. We will understand the overview of Thermal Power Plant i.e its parts such as boiler, turbine etc. Overview of Thermal Power Plant is very important for its better functioning and for its maintenance. The satisfactory design consist of selection of sites; estimation of cost; selection of Boiler, Turbine, Electrical Generator, Cooling System. The Transportation of electrical energy is more economical to the transportation of coal. So, we have to put greater efforts on thermal power plant as it is very economical for us. This reduction can be achieved by improving the efficiency of industrial operations and equipments. Energy plays an important role in identifying energy conservation opportunities in the industrial sector, while they do not provide the final answer to the problem; they do help to identify potential for energy conservation and induces the companies to concentrate their efforts in this area in a focused manner. [ABSTRACT FROM AUTHOR]

Solar-driven water purification has been deemed a promising technology to address the issue of clean water scarcity. However, traditional solar distillers often suffer from low evaporation rates under natural sunlight irradiation, while the high costs of the fabrication of photothermal materials further hinders their practical applications. Here, through the harnessing of the complexation process of oppositely charged polyelectrolyte solutions, a polyion complex hydrogel/coal powder composite (HCC)-based highly efficient solar distiller is reported. In particular, the influence of the charge ratio of polyanion-to-polycation on the solar vapor generation performance of HCC has been systematically investigated. Together with a scanning electron microscope (SEM) and the Raman spectrum method, it is found that a deviation from the charge balance point not only alters the microporous structure of HCC and weakens its water transporting capabilities, but also leads to a decreased content of activated water molecules and enlarges the energy barrier of water evaporation. As a result, HCC prepared at the charge balance point exhibits the highest evaporation rate of 3.12 kg m−2 h−1 under one sun irradiation, with a solar–vapor conversion efficiency as high as 88.83%. HCC also exhibits remarkable solar vapor generation (SVG) performance for the purification of various water bodies. In simulated seawater (3.5 wt% NaCl solutions), the evaporation rate can be as high as 3.22 kg m−2 h−1. In acid and alkaline solutions, HCCs are capable of maintaining high evaporation rates of 2.98 and 2.85 kg m−2 h−1, respectively. It is anticipated that this study may provide insights for the design of low-cost next-generation solar evaporators, and broaden the practical applications of SVG for seawater desalination and industrial wastewater purification. [ABSTRACT FROM AUTHOR]

Coal production often involves a substantial presence of gangue and foreign matter, which not only impacts the thermal properties of coal and but also leads to damage to transportation equipment. Selection robots for gangue removal have garnered attention in research. However, existing methods suffer from limitations, including slow selection speed and low recognition accuracy. To address these issues, this study proposes an improved method for detecting gangue and foreign matter in coal, utilizing a gangue selection robot with an enhanced YOLOv7 network model. The proposed approach entails the collection of coal, gangue, and foreign matter images using an industrial camera, which are then utilized to create an image dataset. The method involves reducing the number of convolution layers of the backbone, adding a small size detection layer to the head to enhance the small target detection, introducing a contextual transformer networks (COTN) module, employing a distance intersection over union (DIoU) loss border regression loss function to calculate the overlap between predicted and real frames, and incorporating a dual path attention mechanism. These enhancements culminate in the development of a novel YOLOv71 + COTN network model. Subsequently, the YOLOv71 + COTN network model was trained and evaluated using the prepared dataset. Experimental results demonstrated the superior performance of the proposed method compared to the original YOLOv7 network model. Specifically, the method exhibits a 3.97% increase in precision, a 4.4% increase in recall, and a 4.5% increase in mAP0.5. Additionally, the method reduced GPU memory consumption during runtime, enabling fast and accurate detection of gangue and foreign matter. [ABSTRACT FROM AUTHOR]

The aim of this work is to study coal steam gasification with various methods of coal in-core treatment in FB using a newly developed thermodynamic calculation method. A calculational study of subbituminous coal steam non-catalytic gasification was carried out using four different methods of coal in-core treatment in single-vessel multisectional fluidized-bed gasifiers. A semi-empirical model based on the entropy maximization thermodynamic method and "restricted equilibria" based on previously obtained experimental data has been developed. Based on thermodynamic calculations, the effect of the leading thermochemical processes and operating parameters of the fluidized bed (temperature, fluidization number, steam/coal ratio feed rate) was revealed. New information was obtained regarding the composition of char and syngas at the gasifier outlet, the syngas heating value, and the cold gas efficiency of the steam gasification of Borodinskiy subbituminous coal char. The results indicate the possibility of significantly accelerating and improving non-catalytic steam gasification in fluidized bed gasifiers through the appropriate organization of in-core coal treatment. Based on the results obtained, the following recommendation is made—when designing multi-section and multi-vessel steam-blown gasifiers, the ratio of residence times should be set in favor of increasing the coal residence time in the steam-blown carbonization zone. Structurally, this can be achieved by increasing the volume and/or area of the steam-blown carbonization section (vessel). [ABSTRACT FROM AUTHOR]

Spent cathode carbon block (SCCB) is a hazardous waste produced by the electrolytic aluminum industry. Collaborative treatment of the SCCB in pulverized coal boilers is a potentially valuable technology. Pilot experiments were carried out on a 240 t/h pulverized coal boiler and its supporting flue gas treatment measures as a function of the mixing ratio of SCCB to verify the feasibility of coal collaborative disposal of SCCB. The thermal conversion characteristics of fluoride after mixing SCCB with coal were studied. A continuous emission monitoring system was used to monitor the impact on SO 2 , NO x and particulate matter in real time. The effectiveness of existing flue gas control measures was evaluated, and optimization suggestions of the flue gas control measures were postulated. The content of heavy metals (Hg, Cd, Ni, Pb, As, Se) in solid waste from co-combustion and the physical phase of solid waste were investigated. In addition, the transformation of heavy metals such as Hg, Cd, Ni, Pb, Cr, As and fluoride in defluorination wastewater during flue gas treatment were analyzed. The results show that it is feasible to use a pulverized coal boiler to dispose SCCB. The existing flue gas treatment measures proved to be appropriate, and desulfurization wastewater can achieve the discharge standards. Defluorination gypsum, fly ash and slag are not hazardous waste. When the mixing ratio of SCCB is increased, the existing neutralization and flocculation precipitation processes of the desulfurization wastewater are affected. It is suggested to add Al 2 O 3 for the defluorination process before the desulfurization tower. [Display omitted] [ABSTRACT FROM AUTHOR]

In order to study the variation law of temperature and stress of overlying rock under the thermal solid coupling condition of underground coal gasification (UCG), the coal measure sandstone samples were heated in one direction, the variation law of temperature and thermal stress was analyzed, and the experiment was analyzed using the numerical simulation software COMSOL. The temperature field, stress field, and volume strain distribution of rock mass are obtained. The results show that in the heating stage of the heating plate, the temperature curve of each measuring point changes rapidly and the temperature rises rapidly, and due to the decrease of the heating rate of the heating plate, the change rate of thermal stress tends to decrease. In the circumferential region of the lower end face, stress stretching occurs and the radial strain is the largest. Under the constraint of unidirectional heating, the temperature distribution of rock along the height direction is obvious. The principal stress is mainly concentrated near the lower end face of the specimen. The research results are helpful to study the thermal damage and fracture characteristics of overlying sandstone of UCG from the perspective of thermal solid coupling. [ABSTRACT FROM AUTHOR]