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The exposure to spontaneous combustion of coal subjected to high ground temperatures increases as the depth of mine excavation increases. To research the oxidative heat release characteristics of deep coal, a study was carried out to characterize the oxidation kinetics and thermal effects on coal in deep thermal environments; deep coals (heat-treated coals) in 30°C (T30), 45°C (T45) and 60°C (T60) environments were prepared using a simultaneous thermal analysis, and the thermal weight characteristics (TG) and thermal release characteristics (DSC) of heat-treated coals were tested by simulating coal samples in different deep thermal environments; the thermal effects of heat-treated coals were analyzed by oxidation kinetic theory. The findings indicated that the characteristic point temperature of the coal gradually reduces (T60 has the lowest oxidation characteristic temperature) as the heat treatment temperature increases, and the maximum mass loss (63.76%) during thermal treatment coal oxidation occurs in the combustion stage. The oxidation reaction mechanism function for the low-temperature oxidation phases of the deep coal conforms to the Z-L-T equation with a three-dimensional diffusion reaction mechanism. As the temperature of the thermal environment is increased, the apparent activation energy of the coal decreases and the exothermic heat increases. This increases the tendency for oxidation of the deep coal, making it more amenable to spontaneous combustion as the ambient temperature at depth rises. The results contribute to a theoretical framework for monitoring and preventing coal spontaneous combustion fires in deep mine excavations. [ABSTRACT FROM AUTHOR]

The long-term accumulation of coal gangue can lead to an increase in internal temperature. If the temperature becomes excessive, it can cause spontaneous combustion, posing serious environmental risks. The process is significantly influenced by external airflow. This study analyzes the thermodynamic properties and oxidation heat release rate of coal gangue samples through laboratory experiments. Subsequently, molecular dynamics (MD) simulations are used to investigate the mechanism of oxidation heat release during the heating process of coal gangue under varying oxygen supply conditions. Based on these findings, a coupled three-field model for the heating process of coal gangue mountains is developed. Using computational fluid dynamics (CFD) methods, transient simulations are conducted to analyze the internal thermal behavior of coal gangue mountains under the influence of external airflow, clarifying the risks of spontaneous combustion. The results indicate that after reaching T 2 (295.16 °C), coal gangue enters an accelerated oxidation phase, with an increased heat release rate, heightening the risk of spontaneous combustion. The oxidation heat release rate of coal gangue accelerates with rising temperature and oxygen concentration, entering a rapid reaction phase after 300 °C, with a sharp increase in reaction rate. Compared to N 2 , coal gangue surfaces exhibit stronger adsorption of O 2 , and temperature changes affect N 2 diffusion more sensitively (O 2 diffusion coefficient increases by 0.312 Å2/ps, N 2 diffusion coefficient increases by 0.334 Å2/ps). The isosteric heat of O 2 adsorption in coal gangue decreases significantly with increasing adsorption amount, and higher temperatures hinder competitive adsorption of O 2. The temperature in the deep and foot areas of the coal gangue mountains is lower, while the middle and upper areas near the slope surface exhibit higher temperatures, indicating a higher risk of spontaneous combustion in these regions. When environmental wind speed is too high or too low, both the internal temperature of the coal gangue mountains and the area of spontaneous combustion risk zones decrease. At a wind speed of 3 m/s, the spontaneous combustion risk zone reaches its maximum area of 73.47 m2, but when the wind speed increases to 7 m/s, the risk area decreases to 65.72 m2. [Display omitted] • The mechanism of exothermic reaction of coal gangue oxidation was described by thermodynamic experiment and MD simulation. • The coupled three-field model of spontaneous combustion of coal gangue mountain was established. • The internal thermal behavior of coal gangue mountain is analyzed by using CFD method. • According to the numerical simulation results, soil mulch method is used to cool down the coal gangue mountain. [ABSTRACT FROM AUTHOR]

This paper addresses the imperative need for environmentally sustainable beneficiation technologies tailored for low-rank coals, constituting about 50% of global coal deposits. The focus is on recent advancements in bio-beneficiation methods for sub-bituminous coals in thermal power stations, employing "bio extract of Carissa carandas fruits" with lower concentrations of Hydrofluoric acid. The objective is to enhance coal quality by reducing ash content and adjusting mineral composition to mitigate clinker formation during combustion. The research investigates simultaneous coal treatment with bio extract and low-concentration Hydrofluoric acid. While traditional beneficiation techniques, such as physical, chemical, and physicochemical methods, have been extensively used, a research gap is identified in green methods utilizing biomaterial extracts to remove/reduce metal oxides from coal and the need to regulate the silica-to-alumina ratio in coal composition, for resolving the issue of clinker formation. The investigation demonstrates the bio extract's efficacy in leaching alumina, iron oxide, and alkali/alkaline earth metal oxides from coal, significantly reducing ash content. Consequently, there is a remarkable increase in coal's gross calorific value post bio-beneficiation, accompanied by a significant reduction in sulfur content in addition to the decrease in tendency of clinker formation of coal during combustion. This study is a significant contribution to the field of environmentally friendly coal beneficiation and to reduce the tendency of clinker formation during combustion. [ABSTRACT FROM AUTHOR]

Talcher Coalfield is one of the most important coalfields considering thermal grade coal reserves in India; nevertheless, hardly any published geophysical study is available for mapping the subsurface coal, in-crop zone, fault location, formation boundary, etc. In the present study, a combined analysis of electrical resistivity tomography (ERT) in five profiles and high-resolution shallow seismic (HRSS) survey in two profiles was carried out in Goribandh at the northern–eastern part of the Talcher Coalfield, Odisha, India, to study the structural control of coal seams and to delineate the coal potential zone and non-coal zone. Geological core data from three boreholes were utilized to validate the ERT and HRSS results. Three ERT profiles (ERT_P1, ERT_P2, and ERT_P3) data were acquired in perpendicular to the strike direction, and two ERT profiles (ERT_P4 and ERT_P5) data were collected in the strike direction. The purpose of the acquisition of ERT data in the strike direction is to correlate the resistivity values at the cross point of dip lines and strike lines. Two HRSS profiles (HRSS_P1 and HRSS_P2) data were collected along the same two corresponding dip lines of the ERT profiles (ERT_P1 and ERT_P2). The ERT data were collected using Wenner–Schlumberger array at 10 m electrode spacing with multiple roll-along sequences to cover the desired profile length with an approximate profile line spacing of 200 m. The Res2Dinv program was used to execute the inversion of the combined data set. The HRSS data were acquired by 'End-on-Shooting' method using 24-fold common depth point survey at 4 m geophone spacing with multiple roll-along sequences to cover the desired profile length with approximate profile line spacing of 200 m, where near trace and far offsets trace were 88 and 276 m, respectively. HRSS data were analyzed using Paradigm 19 seismic processing software. Comprehensive analysis of five numbers of 2D ERT sections (ERT_P1-ERT_P5) and two numbers of HRSS sections (HRSS_P1 and HRSS_P2) indicates that the southern part of the study area is characterized by relatively low to moderate high resistivity (100–500 Ωm) distribution while seismic sections demonstrate multiple strong reflecting horizons, due to carbonaceous beds as identified in the boreholes, indicating Barakar formation. The northern part is characterized by high resistivity (200–1000 Ωm) distribution, while seismic sections exhibit multiple distributed minor reflectors due to boulder beds and or compact sandstone. The combined study of ERT and HRSS data delineates a prominent fault zone F4, indicating a contact boundary between the Talchir and Barakar formations. [ABSTRACT FROM AUTHOR]

Fly ash is the primary residue produced in huge amounts by coal combustion in thermal power plants, which needs to be utilized appropriately. In this connection, an experimental study was conducted with fly ash alone and in combination with soil for the treatment of simulated dumpsite leachate in constructed wetland (CW) (vertical flow) systems containing Canna+ Typha plants. The study revealed that the fly ash + soil mixture as a CW substrate showed better removal efficiency of chemical oxygen demand (COD), phosphate (), total nitrogen (TN), and chloride (Cl–) by 97.3, 99.4, 94.5, and 89.6%, respectively, in comparison to the fly ash alone which was shown to yield the corresponding values of 88.5, 94.1, 84, and 73.2% of the efficiency in the removal of these pollutants from simulated dumpsite leachate. [ABSTRACT FROM AUTHOR]

This study sought to construct a superstructure aimed at determining a optimal hydrogen supply chain based on both economic and environmental criteria, with a focus on utilizing potential biomass waste for hydrogen synthesis. To evaluate the mathematical model, four case studies were devised. Case 1 identified natural gas steam methane reforming as the preferred hydrogen production method due to its lowest overall cost of USD $51.96 million per year and an annual production of 1.90 × 108 kg of H 2. In contrast, Case 2 favored a combination of empty fruit bunch (EFB) steam gasification and coal gasification technologies, which resulted in lower CO 2 -equivalent emissions of 926.88 × 106 kg CO 2-eq per kg of H 2 produced annually. Case 3 constituted a multi-objective scenario assessing both economic and environmental performances, while Case 4 served as a sensitivity analysis, assigning higher environmental weightage to identify sustainable pathways required toward net zero carbon emissions by 2050. In Case 3, steam gasification of palm kernel shell and empty fruit bunch, along with coal gasification were identified as the optimal hydrogen synthesis pathways, targeting a total cost of $ 309.31 million and emitting 938.50 × 106 kg CO 2-eq emission per kg of H 2 produced annually. In Case 4, an annual total cost of $ 316.86 million was recorded, with 936.45 x 10 6 kg CO 2-eq emitted per kg of H 2 produced. These findings underscore the importance of balancing economic considerations with environmental sustainability in hydrogen pathway selection. • Multi-objective optimisation identifies optimal hydrogen pathways in Malaysia. • Combination of steam gasification and coal gasification reduces CO 2 emissions. • Life cycle assessment confirms steam gasification as a viable renewable pathway. • Integration of economic and environmental for hydrogen pathway selection is vital. [ABSTRACT FROM AUTHOR]

A WG/C/XG (water glass/sodium carboxymethyl cellulose/xanthan gum) gel was created in this study by incorporating a tracer indicator into the fire protection material. The gel is both a tracer and flame retardant. First, scanning electron microscopy, UV spectrophotometer, and chromatography-mass spectrometer was used to characterize the samples. The microstructure of the WG/C/XG gel was investigated, as well as its impact on high-temperature response. The average rate of tracer gas release varies significantly before and after 55°C. Moreover, the release patterns of the two tracer gases are similar, indicating that the WG/C/XG gel is suitable for the solid loading of tracer gases. A thermal analyzer and programmed warming oxidation experiment analysis were used to investigate the inhibitory effect of WG/C/XG gel on the oxidation of spontaneous coal combustion. The experimental results demonstrated that the WG/C/XG gel improved the thermal stability of coal samples and inhibited spontaneous coal combustion. In mined areas, WG/C/XG gel is an excellent tracer material. [ABSTRACT FROM AUTHOR]

Thermal stimulation can activate adsorbed gas, enhancing cross-scale gas transport (CSGT) in coal. Nevertheless, the thermal stimulation mechanism of CSGT remains unclear. In this study, He and CH4 desorption experiments under different temperatures were conducted, and propagation characteristics of longitudinal and transverse waves of gas-containing coal before and after thermal stimulation were tested. Based on the results, the intrinsic relationship between gas diffusion parameters and thermal stimulation temperatures was elucidated, and the dynamic mechanical responses of gas-containing coal induced by thermal stimulation were analyzed. It has been revealed that more gas of surface diffusion state transfers into the gas of bulk diffusion state as the thermal stimulation temperature rises, and the gas-containing coal occurs three phenomena, i.e., inward expansion-fracture compression, outward expansion-fracture enlargement, and outward expansion-coal damage. Additionally, a CSGT model was constructed based on the micro-scale fractal geometry of coal, and how changes in pore-fracture scale, matrix gas pressure, and adsorbed gas content influence the multi-modal gas diffusion conductivity under varying temperatures were analyzed. The results suggest that the gas emission rate is sequentially controlled by the free gas diffusion, the desorption of mono-layer adsorbed gas in diffusion pores, and the surface diffusion of adsorbed gas in filling pores. Ultimately, the mechanical response of gas-containing coal induced by thermal stimulation was analyzed considering hydrodynamics and geomechanics coupling, fining that the critical transformation and instability temperature have a significant influence on stimulation mechanisms. The research can provide a theoretical reference for thermal stimulation of gas drainage in deep coal seams. [ABSTRACT FROM AUTHOR]

The preparation of gel foams with high stability for inhibiting coal spontaneous combustion remains a huge challenge. In this paper, a highly stable gel foam (SCTH) was developed by introducing nano-hydroxyapatite (HAP) into gel foam system (sodium alginate/calcium L-lactate/tannic acid/composite forming agent). The effects of HAP on the foam performances of SCTH were analyzed. The results showed that HAP could improve the stability of SCTH by forming hydrogen bonds, metal ion bonds with the system and interfacial barriers. After 100 days, SCTH without HAP had only 44.8% of the foam volume remaining. The SCTH with 1.2 wt% HAP had 80% of the volume remaining. In addition, the SCTH had better safety. Thermogravimetric analysis showed that the SCTH could improve the maximum weight loss rate temperature, and increase the residual weight of the coal after thermal decomposition. The coal temperature-programmed oxidation experiment showed that the SCTH could increase the temperature of coal entering the rapid oxidation stage from 120 to 190°C, and the CO inhibition rate was 85.3% at 200°C. Fire suppression experiment showed that the SCTH could reduce the temperature of burning coal by 81.9% within 10 min, thus achieving rapid fire suppression. X-ray photoelectron spectroscopy analysis showed that the SCTH could more effectively reduce the total content of C=O and -COO in coal and block the chain cycle reaction of coal. This work presents a new design idea for using multifunctional nanoparticles to prepare highly stable gel foams with excellent inhibition performance of coal spontaneous combustion. [ABSTRACT FROM AUTHOR]

Thermogravimetric (TG) experiments were carried out on the combustion of coal, peanut shells and their mixtures with different blending ratios in an air atmosphere to study the combustion characteristics of single particles and mixtures of the two, as well as the interactions between peanut shells and coal, and to find out the kinetic parameters of the combustion process, and to determine the optimal blending ratios. And the heat source plant 58 MW circulating fluidized bed boiler was used to carry out field mixing experiments on coal and peanut shells with different blending ratios to explore the pollutant emissions. The results show that blending peanut shell biomass can significantly improve the combustion characteristics of coal combustion and make combustion more likely to occur. The synergistic effect of peanut shells and coal was most significant when the blending ratio of peanut shells was 40%, and the mixture samples had the best combustion performance and the highest combined combustion properties index of 1.08 × 10–7. Compared with coal combustion alone, the emission concentrations of SO2 and NOx were reduced by 77.07% and 30.70% respectively when the ratio of peanut shell blending was 40%, the emission of dust showed a tendency of decreasing and then increasing, and the carbon content of fly ash was reduced from 7.55% to 5.86%. In our study, 40% peanut shells + 60% coal is the optimum blending ratio for mixed combustion. The results provide theoretical and technical support for energy saving, pollution reduction, and carbon emission reduction in coal-fired heating units. [ABSTRACT FROM AUTHOR]

Given thermal coal's significance as a tactical energy source, price projections for the commodity are crucial for investors and decision-makers alike. The goal of the current work is to determine whether Gaussian process regressions are useful for this forecast problem using a dataset of closing prices of thermal coal traded on the China Zhengzhou Commodity Exchange from January 4, 2016, to December 31, 2020. This is a significant financial index that has not received enough attention in the literature in terms of price forecasting. Our forecasting exercises make use of Bayesian optimizations and cross-validation. The price from January 02, 2020, to December 31, 2020 is successfully predicted by the generated models, with the out-of-sample relative root mean square error of 0.4210%. Gaussian process regressions are shown to be useful for the thermal coal price forecast problem. The outcomes of this projection might be used as independent technical forecasts or in conjunction with other forecasts for policy research that entails developing viewpoints on price patterns. [ABSTRACT FROM AUTHOR]

This paper presents the results of the development of stabilization measures aimed at the removal of zinc with the products of melting and accumulation of titanium in the hearth of a blast furnace. The relevance of the development and use in practice of such measures is due to the unstable fuel and raw materials conditions for the production of cast iron, when their stabilization is a complex and difficult task, as well as the need to extend the campaign of blast furnaces during the overhaul period. The negative effect of zinc oxides on the condition of the blast furnace shaft lining, accompanied by slab formation, and the overconsumption of specific coke consumption, which occurs when zinc circulates in the volume of the blast furnace, require measures to remove zinc from the smelting products. The article proposes such measures, which consist of flushing according to the proposed schedule during the operation of the blast furnace at planned blowing parameters and with the provision of the necessary thermal reserve. In order to lengthen the campaign of a blast furnace, one of the most common methods for protecting the hearth lining is the periodic introduction of titanium‐containing materials into the charge of blast furnaces. The entry of titanium oxides into the furnace, as a rule, is ensured by the use of concentrate or specially prepared ilmenite briquettes with a high titanium content as part of the sinter charge, which can be introduced directly into the composition of the blast furnace charge. The article analyzes the experience of using titanium‐containing materials as part of a blast furnace charge and formulates measures to intensify skull formation in the hearth. [ABSTRACT FROM AUTHOR]

A Sapozhnikov plastometer is equipment that is commonly used, particularly in Asia, for measuring the contraction of the coal bed as well as the plastic layer thickness during the coking process. The relationship between the Sapozhnikov contraction X and the maximum plastic layer thickness Y values and other thermal rheology testing techniques is not fully understood. It leads to difficulties in the interpretation of data using different thermal rheology properties measurement techniques. In this work, a series of coal samples were analyzed in parallel using the automatic Sapozhnikov plastometer, the Gieseler plastometer, and the Ruhr dilatometer. The measurement results were compared to assist in the interpretation of data generated using different coal thermal rheology property measurement techniques. The Sapozhnikov X results are found not comparable due to the difference in sample particle size and testing conditions for component coals with the wide range of maximum mean reflectance (Ro), but a significant linear correlation on the contraction/expansion behavior between Sapozhnikov and Ruhr dilatation test is observed for experimental coal blends Ro between 1.00 and 1.20. Sapozhnikov Y results are linearly related to the melting range from both the Gieseler plastometer and the Ruhr dilatometer for all the experimental single coals and coal blends. [ABSTRACT FROM AUTHOR]

Coalbed methane thermodynamic extraction, as an emerging ECBM recovery method, can effectively improve gas recovery rates. And clarifying methane diffusion and migration law in coal under thermal stimulation is crucial for the selection of its process parameters. Based on laboratory methane adsorption-release experiments, the evolution law of methane diffusion characteristics with temperature and pressure was studied, and the control mechanism of heat-dependent methane diffusion behavior was explored. The results show that both thermal stimulation and high adsorption pressure accelerated the methane diffusion rate in coal. Adsorption pressure had little effect on methane diffusion percentage, but thermal stimulation promoted a significant increase in diffusion percentage and improved the net methane yield. The influence mechanisms of adsorption pressure and thermal stimulation on methane diffusion characteristics are elucidated in relation to the amount and proportion of methane-activated molecules in the diffusion process. The constant diffusion coefficient of methane is heat-dependent, based on which a diffusion model is derived to accurately predict the methane release process in coal. Additionally, temperature has a more important effect on transient diffusion coefficient than pressure. Thermal stimulation leads to a net increase rather than a decrease in diffusion coefficient in the early diffusion stages and can also accelerate the attenuation of diffusion coefficient, with this intensifying effect becoming more pronounced at higher temperatures. The research results can provide some reference for the determination of coal seam gas content and the selection of heat injection process parameters. [ABSTRACT FROM AUTHOR]

To investigate the influence of moisture on the exothermic properties of coal oxidation, this study investigated the variation in thermal effect and radical parameters in the oxidation process of coal under different moisture content. This was achieved through thermogravimetric–differential thermal experiments and electron spin resonance experiments. Additionally, the study analyzed the impact of free radicals on the characteristics of the thermal effect of coal at different oxidation stages using the product–moment correlation method. The results indicate that the moisture content of 8% is a critical point for promoting or inhibiting the oxidation reaction of coal. Below this threshold, it promotes the oxidation reaction, while above it, it plays an inhibitory role. The most significant promotional effect was observed at 8% moisture content, which increased both the weight loss and heat release by 8.61% and 1567.04 J/g, respectively, while also significantly enhancing free radical species and complexity. Conversely, when the moisture content of coal reached 20%, there was a notable inhibition effect, with a reduced weight loss and exothermic capacity by 4.94% and 2705.03 J/g, respectively, along with decreased free radical species and complexity. The free radical species and heat effect parameters in coal showed a strong correlation at all stages of low-temperature oxidation, thus indicating that g-factor can characterize the coal oxidation process to some extent. [ABSTRACT FROM AUTHOR]

Based on the Thermal Decomposition of Xishan coal Experiments and ReaxFF MD Simulations, the study investigated the processes and product changes in the thermal decomposition of coal and the pyrolysis of coal with Na2SO4. The results indicate that the initial temperature of thermal decomposition of Xishan coal is around 300 °C in experiments and approximately 1600 K in molecular simulations. The addition of Na2SO4 advances the initial pyrolysis temperature and promotes the generation of total number and types of products. Xishan coal pyrolysis generates a large number of small molecular gases and free radicals, and the addition of Na2SO4 promotes the generation of CO, CH4, and H2S, as well as the accumulation of a significant number of free radicals. Free Na mainly affects the evolution of N elements, promoting the formation of N into amino groups, and Na easily combines with sulfur-containing intermediates. Through the extraction of sulfur-containing intermediates and the analysis of the influence of free radicals, it was found that S elements Xishan coal ultimately forms H2S. This study microscopically confirms that in the coal with Na2SO4 system, H2S originates from the hybridised sulfur atoms in the carbon chain and free ${\rm SO}_4^{2-}$ SO 4 2 − . [ABSTRACT FROM AUTHOR]

Based on the Thermal Decomposition of Xishan coal Experiments and ReaxFF MD Simulations, the study investigated the processes and product changes in the thermal decomposition of coal and the pyrolysis of coal with Na2SO4. The results indicate that the initial temperature of thermal decomposition of Xishan coal is around 300 °C in experiments and approximately 1600 K in molecular simulations. The addition of Na2SO4 advances the initial pyrolysis temperature and promotes the generation of total number and types of products. Xishan coal pyrolysis generates a large number of small molecular gases and free radicals, and the addition of Na2SO4 promotes the generation of CO, CH4, and H2S, as well as the accumulation of a significant number of free radicals. Free Na mainly affects the evolution of N elements, promoting the formation of N into amino groups, and Na easily combines with sulfur-containing intermediates. Through the extraction of sulfur-containing intermediates and the analysis of the influence of free radicals, it was found that S elements Xishan coal ultimately forms H2S. This study microscopically confirms that in the coal with Na2SO4 system, H2S originates from the hybridised sulfur atoms in the carbon chain and free ${\rm SO}_4^{2-}$ SO 4 2 − . [ABSTRACT FROM AUTHOR]

Air humidity has a significant effect on the characteristic parameters and heat changes of the coal spontaneous combustion process. In this study, a self-built precision humidity-generating device with adjustable humidity was used to investigate the effect of different humidity conditions on the spontaneous combustion process of coal. The release of indicator gases was determined by a humidity-generating unit in conjunction with a temperature-programmed device for coal oxidation, and the effect of air humidity on coal spontaneous combustion was studied from a macroscopic perspective. A quantitative study of the effect of air humidity on the heat released during the spontaneous combustion of coal was carried out by obtaining data for exothermic heat release intensity by conducting thermal analysis. Meanwhile, the numerical simulation method was used to study the influence of air humidity on the heat released during the coal spontaneous combustion process. The experimental results indicated that the introduction of moist air could significantly increase the oxygen consumption rate of the coal samples and promote the production of CO and CO2. In the slow oxidation stage, the air humidity has a greater effect on the heat release than that in the accelerated and fast oxidation stages. The simulated results of heat release in the slow oxidation phase are consistent with the experimental data, verifying that the moisture in the air can increase the amount of heat release and promote the coal-oxygen reaction. When the moisture in the air first came into contact with the coal, it released a large amount of adsorption heat in a short time, which increased the coal temperature. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study is to analyze and evaluate the consumption of thermal energy in a coal mining enterprise with separate business units, in the context of securing energy reserves and effectively managing the consumption of this energy. Design/methodology/approach: Based on the aggregation and analysis of historical data of thermal energy consumption, the method of statistical analysis of aggregated data from individual business units of the coal mining company was applied. Findings: The applied statistical analysis of the aggregate data made it possible to verify the planned short-and long-term activities for each group of facilities of the coal mining company. Research limitations/implications: The further direction of the research requires verification of the obtained results of the statistical analysis, after completing the data of thermal energy consumption in the following years and correlating the obtained results with the introduced pro-efficiency measures in the enterprise so as to clarify the division of the enterprise's facilities into individual groups. Practical implications: Statistical analysis of thermal energy consumption, can become an effective tool to support the process of managing pro-efficiency measures in mining enterprises with separate business units. Social implications: The right approach of coal mining companies to thermal energy analysis and management can contribute to securing energy reserves for the local environment in which the company operates. Originality/value: The presented classification of facilities into groups A, B and C and the use of statistical analysis to verify the introduced measures to reduce thermal energy consumption have not yet been introduced and tested in the Polish coal mining industry. [ABSTRACT FROM AUTHOR]

The paper is using the Continuous Wavelet Transform (CWT) and the OLS estimator to examine the relationship between energy prices (coal and gas), inflation and economic growth in Mozambique. Coal and gas are the primary commodity and source of revenue for the country. The research uses quarterly data from 2001 to 2022. Among other results, we found evidence of high coherence between macroeconomic variables (inflation and real GDP growth rate) and energy prices (thermal coal and natural gas prices) only for the frequency intervals between 1.5 and 4 years (short term). The results hold even after controlling for the real GDP growth and exchange rate; we concluded that only in the short term (1.5–4 years), there is high coherence between energy prices and inflation in the time interval between 2004 and 2012. This finding indicates no relation between energy prices, inflation and economic growth in Mozambique. Furthermore, the OLS estimates substantiate the wavelet result, showing no impact. In this context, we can conclude that there is probably a 'Dutch disease' or 'resource curse' that negates the positive effects of exploiting these resources on short‐ and long‐term economic growth. [ABSTRACT FROM AUTHOR]

The co‐pyrolysis behavior of low‐grade coal with two different feedstocks (beeswax and petroleum wax) at different compositions (w/w) [(75:25), (50:50), (25:75)] is investigated by using a thermogravimetric (TG) analyzer under the non‐isothermal condition at a constant heating rate of 20°C/min from an ambient temperature to 900°C under nitrogen atmosphere. The kinetic and thermodynamic analysis for the thermal decomposition of the sample parameters was carried out by applying the model fitting Coats–Redfern method to the thermogravimetry data of different feedstocks. The activation energy of thermal degradation of coal is found to be 55.8 kJ/mole. A decrease in activation energy is observed by the addition of 25% and 50% waxes in the blended sample and the blended sample with 25% wax and 75% coal has the lowest activation energy. The activation energy for coal‐beeswax blend (75:25) is 35.718 KJ/mol, but it is 34.237 KJ/mol for coal‐petroleum wax blend (75:25). The value of ∆H decreases by the addition of waxes and follows the order (Coal: Feedstock) {(75:25) < (50:50) < (25:75)}, while that of value of ∆S increases by the addition of waxes and follows the order {(75:25) > (50:50) > (25:75)}. However, the value of ΔG does not significantly shift as the blend ratio of the feedstocks is altered. The addition of both feedstocks with the coal sample showed some degree of synergy. The result illustrates that the co‐pyrolysis of coal with wax be energy economical than individual pyrolysis and this study would give precious scope to design a more efficient conversion system. [ABSTRACT FROM AUTHOR]

The utilization of coal for hydrogen generation presents a multifaceted approach employing processes like coal gasification, pyrolysis, or high-temperature steam reforming. These methodologies entail reacting coal with steam or oxygen under elevated temperatures, yielding a gas mixture comprising hydrogen, carbon monoxide, and various byproducts. This paper delves into the exploration of hydrogen generation from coal, highlighting techniques such as gasification, pyrolysis, and other emerging methods. Notably, hydrogen discoveries within coal basins have garnered significant attention due to their implications for energy production and environmental sustainability. Certain coal basins harbor deposits rich in hydrogen, surpassing conventional coal reserves in their hydrogen content. These hydrogen-rich coals, including select sub-bituminous and lignite varieties, offer promising avenues for hydrogen production and utilization. However, the utilization of coal for hydrogen generation is not without its challenges. Technical hurdles, such as process efficiency and environmental concerns, demand rigorous investigation and innovative solutions. This paper addresses the challenges faced in coal-based hydrogen generation while elucidating the potential future prospects. It explores avenues for enhancing process efficiency, mitigating environmental impacts, and integrating coal-based hydrogen generation into broader energy strategies. Moreover, it underscores the importance of interdisciplinary research and collaboration in unlocking the full potential of coal for sustainable hydrogen production. [ABSTRACT FROM AUTHOR]

For the established steam coal preparation plant that uses dense-medium shallow groove separation process, reducing the separation lower limit is conducive to improving its economic benefits. Reducing the lower limit to be consistent with the mesh size of the demedium screen, which is 1 mm, so that more coal can be separated without affecting the normal operation of the entire system. A process of 1 mm desliming before separation and dense-medium shallow groove separation was proposed in this paper. The kinematic characteristics and desliming performance of rigid screen surface and elastic screen surface were compared and analyzed. The separation performance of each size coal in the dense-medium shallow groove separator was investigated and the ratio of upward medium flow and horizontal medium flow was optimized. The industrial experiment results showed that the screening efficiency and desliming efficiency of elastic screen surface were increased by 4.31% and 4.37% respectively compared with rigid screen surface. The separation performance of each particle size coal in the dense-medium shallow groove separator became worse with the decrease of particle size. When the ratio of upward medium flow and horizontal medium flow was 8:2, the separation performance of 200–1 mm size coal was the best, and its probable error was 0.04 g/cm3. The optimized process could significantly decrease the slime content in separation system and improve clean coal yield. [ABSTRACT FROM AUTHOR]

For the current coal spontaneous combustion fire risk evaluation method has the problems of single evaluation dimension, incomplete evaluation index and unreliable evaluation results. However, the coal spontaneous combustion fire risk evaluation can effectively guide coal mine fire prevention and control. Therefore, a multi-indicator quantitative risk evaluation method combining analytic hierarchy process (AHP) and linear interpolation for different periods of coal spontaneous combustion is proposed as a way to improve the rationality of coal spontaneous combustion fire risk evaluation. The continuous segmental evaluation model was established based on the factors that influence the three periods of coal spontaneous combustion (Latent Period, Self-heating Period and Combustion Period). The latent period evaluation model was established based on the fire-prone nature of coal, coal seam occurrence, mining technology, and fire prevention measures. The self-heating period evaluation model was established based on the degree of self-heating of coal, absolute CO generation, and Graham index. The combustion period, there was already a spontaneous combustion fire, directly set the fire risk score to 0. The score could fully reflect the level of coal spontaneous combustion fire risk. The higher the score, the relatively smaller the risk of coal spontaneous combustion, and vice versa, the relatively larger. According to this risk evaluation model, the risk of coal spontaneous combustion in the 2−2 coal seam of a coal mine in Shaanxi Province was evaluated. The result shows that the level of coal spontaneous combustion risk of 2−2 coal seam in this coal mine is in a safer state, and this result is consistent with the actual situation. The multi-indicator quantitative evaluation of different periods of coal spontaneous combustion effectively improves the accuracy of fire risk evaluation. Therefore, the evaluation model has certain theoretical guidance for the control of coal spontaneous combustion risk in coal mines. [ABSTRACT FROM AUTHOR]

In the article low-temperature pyrolysis of coal of "Saryadyr" deposit with determination of physical and chemical properties of coal and products of its thermal destruction is carried out. Elemental analysis of coal and analysis of mineral part of coal were carried out. 6 parallel experiments of the process of lowtemperature pyrolysis of coal were carried out, as a result of which the yields of such products as semicoke, tar, combustible gas were determined, as well as their main characteristics (component composition, calorific value, etc.) were determined. The convergence of the results (from 6 experiments) is quite satisfactory. The thermal balance of coal pyrolysis was carried out taking into account the average yields of products. [ABSTRACT FROM AUTHOR]

Thermal activated coal gangue as an auxiliary cementing material to replace part of cement to prepare cement mortar, systematically studies the effects of different amounts of thermal activated coal gangue on the compressive strength and flexural strength of cement mortar, and the mechanism of thermal activation of coal gangue to enhance the mechanical strength of cement-based materials was explored. The results show that in the process of using thermally activated coal gangue to replace part of cement to pre-pare mortar, proper amount of thermally activated coal gangue has good pozzolanic effect and micro aggregate effect, which can promote the formation of cross-linked network C--S--H gel in mortar matrix, enhance the filling effect of pores in mortar matrix, improve the microstructure of mortar matrix, and then achieve the purpose of improving the mechanical strength of cement-based materials. When the amount of thermal activated coal gangue is 20%, the compressive strength and flexural strength of the mortar sample for 28 d after hydration can reach 46.2 MPa and 6.79 MPa, and the mechanical strength is equivalent to that of pure cement mortar, which can fully meet the requirements of the general construction industry. [ABSTRACT FROM AUTHOR]

Coal based thermal power plants contribute about ~ 72% of the power generation in India. Indian coal is of bituminous type, having a high ash content with 55–60% ash. Due to considerable environmental importance the collected fly ash has become a subject of worldwide interest in recent years. In the present study radon exhalation rate and the activity concentration of 226Ra, 232Th and 40K radionuclides in fly ash samples from Kasimpur Thermal Power Plant, Aligarh, Uttar Pradesh, India have been measured by 'Sealed Can technique' using LR-115 type II detectors and a low-level NaI (Tl)- based gamma-ray spectrometer, respectively. Radon exhalation rate has been found to vary from 57.1 ± 5.3 to 119.4 ± 7.7 mBq m−2 h−1 with an average value of 87.3 ± 5.8 mBq m−2 h−1. Activity concentration of 226Ra ranged from 20.0 ± 8.5 to 30.0 ± 9.7 Bq kg−1 with an average value 23.4 ± 9.0 Bq kg−1, 232Th ranged from 17.0 ± 9.9 to 69.0 ± 13.8 Bq kg−1 with an average value of 46.5 ± 12.1 Bq kg−1 and 40K ranged from 130.0 ± 7.2 to 332.0 ± 11.1 Bq kg−1 with an average value of 177.0 ± 8.1 Bq kg−1. [ABSTRACT FROM AUTHOR]

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]

Mine coal spontaneous combustion is one of the five major natural disasters in coal mines, and determining the concealed fire source locations of coal spontaneous combustion is key to solving the problem. This paper determines the thermal conductivity of coal samples through a spherical heat conduction model, and based on experimental data, analyzes the fitting relationship between thermal conductivity and heating voltage, the outer wall temperature of the inner sphere, and the location of high-temperature points under different voltage conditions. The study concludes that there is a linear relationship between thermal conductivity and both heating voltage and outer wall temperature, with a correlation coefficient greater than 0.9. In ideal conditions, the highest temperature is located at the center of the flat wall of the spherical heat conduction model. This re-search provides a mathematical basis for the prevention and control of mine coal spontaneous combustion fires. [ABSTRACT FROM AUTHOR]

The paper presents a specific method of environmental impact assessment applied in Strategic Environmental Assessment (SEA) for the National Emission Reduction Plan (NERP) in the Republic of Serbia, based on air quality. The specificity of the approach is in the application of a semiquantitative method of multicriteria evaluation based on air dispersion modeling and the integration of SEA goals, indicators and criteria for assessing the impact of the NERP on the quality of air and other environmental elements in this method. When predicting changes in air quality for the planning horizon to 2028, the physical, geographical and climatic characteristics of the area were taken into account, as well as technical measures to reduce SO2 emissions, since this was the dominant pollutant from the Serbian coal-fired power plants studied by the NERP. Air pollution modeling was carried out using the AERMOD software package based on the data collected, and the quantitative results obtained were used in a multicriteria evaluation as part of the SEA. The results of the research indicated the importance of applying this approach in order to significantly increase objectivity in the SEA process, since it is an important element of decision making at the strategic level. In addition, a comparative presentation of the modeling results before and after application of the NERP was an important part of the SEA process, and it provided a clear insight into expected changes in the air quality. This is a key argument for making appropriate policy decisions on spatial, energy, environmental and socio-economic development in the Republic of Serbia, which, like other developing countries, is sluggishly following global trends in energy transition. [ABSTRACT FROM AUTHOR]

India is one of the more producer of the electricity in the world. Major source of generation of electricity in India is due to coal. As per National Electricity plan, the government has approved to install 50,025 MW coal based thermal power plants. But, It was observed that more amount of coal is using to generate the electric power than reference level. This was because of presence of magnetic elements in the bed material which was used in boiler to maintain desired temperature at the bottom of the boiler. The efficiency of the boiler is decreasing due to damage caused by the magnetic elements in the bed material. These magnetic elements decrease the reference temperature in the boiler and consequently the boiler operator is allowing excess amount of coal to maintain the reference temperature in the boiler. Because of this, excess amount of coal is used to generate electric power and there by producing excess amount of ash. This can be reduced by constructing a magnetic separator near the bed material stack point and verifying the magnetic elements in the bed material thoroughly. Due to this separator, the boiler efficiency can be maintained nearer to the designed value, usage of excess amount of coal can be reduced. The investment cost for erecting the magnetic separator can be obtained in a couple of years. As a case study, the SKS Power Generation CG Ltd, Raigarh is considered. The proposed theme is applied in MATLAB and the cost of thermal power plant is calculated and existing making data. The obtained results showed that the proposed structure gives a feasible system and best experience and is proved that it is essential for solving such type of assignments. [ABSTRACT FROM AUTHOR]

Domestic heating transitions must balance environmental and social policy goals, which leads to conflicts between cost, pace, and cleanliness. It is a challenge for urban policies in Central European cities, where outdated social housing stock meets increasing people's aspirations on improving air quality and climate change mitigation goals. Utilizing insights from the case study of Warsaw, this research evaluates the patterns of domestic coal phase-out in social housing, combining in-depth analysis of unique heating transition data with official census records and qualitative analysis. The investigation uncovers reprivatization, revitalization, and rationalization as three avenues through which heating transitions may inadvertently contribute to gentrification and displacements. These findings underscore the dual role of heating transitions in social housing, acting as a mitigation strategy or a catalyst for socio-spatial segregation, reproducing the ideologies of the dominant urban policy paradigm. [ABSTRACT FROM AUTHOR]

Primary and secondary hole defects in the process of coal mining will have an important impact on the stability of coal, therefore, the study of the mechanical and related characteristics of coal containing hole defects is of great significance for safe production and engineering practice. In this paper, the RMT-150 rock mechanics system is used to carry out uniaxial compression damage tests on coal with different hole sizes, and the whole process is recorded by simultaneous infrared radiation monitoring, based on which the influence of hole size on the change of physical properties and infrared radiation temperature response is analyzed. The results found that: the hole defect has a deteriorating effect on the strength of the coal, and the hole size is negatively correlated with the uniaxial compressive strength and elastic modulus. When the coal doesn't contain a hole or the hole size is small, the load damage is mainly shear, and as the hole size increases, the tensile damage characteristics gradually become significant. Hole defects cause the initial differential maximum infrared radiation temperature and the initial differential lowest infrared radiation temperature of coal surface thermal images to diverge in a " < " trend, while the initial differential average infrared radiation temperature monotonicity is obvious. The slope of linear change in the middle section of the coefficient of variation of infrared radiation temperature gradually increases with the increase of the hole, while the change of entropy value is generally higher than that of intact coal. The infrared temperature field of the coal containing hole is approximately Bi-gaussian distribution, and the instantaneous trend of the fitted distribution curve shifts to the right and overall to the right as the test progresses, and the curve shifts from a lean and tall form to a short and fat form. [ABSTRACT FROM AUTHOR]

To effectively utilize ventilation air methane (VAM), it is proposed to pass it into the boiler of the coal‐fired power plant for mixed combustion. However, the different types of thermal coal utilized present distinct characteristics when mixed with VAM. In this paper, lignite, bituminous coal, and anthracite are selected to study the CH4 conversion rate, system ignition temperature, and NO emission characteristics of the VAM‐pulverized coal coupled system on a fluidized bed experimental platform. The experimental results show that the ignition temperatures of VAM are 748, 736, and 732 °C when the CH4 concentration is 0.25, 0.5, and 0.75%. After the addition of thermal coal, the ignition temperature decreased significantly. When the CH4 concentration is 0.25%, the ignition temperature of the lignite‐VAM system is the lowest, which is 450 °C. Anthracite has the strongest catalytic effect on CH4 combustion. When the heating rate is 5 °C /min, the reaction rate of CH4 is the fastest in the anthracite‐VAM coupled system. Under laboratory conditions, the peak NO concentration in the coal‐VAM coupled system was lignite > bituminous coal > anthracite at different CH4 concentrations, and the CH4 in VAM had a reducing action on the NO generated during mixed combustion, with a stronger reducing effect observed as the CH4 concentration increased. The results of this study can lay the foundation for the industrial application of the mixed combustion of VAM and thermal coal, and be of great significance for solving the practical problems caused by the change of boiler coal types. © 2024 Society of Chemical Industry and John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Several recently signed environmental agreements and protocols emphasize the global need to reduce GHG emissions, with a focus on limiting coal consumption due to high NOx and CO2 emissions. However, many countries, including those in the Western Balkans, rely heavily on coal for electricity generation. The outdated thermal power plant infrastructure in these regions poses a major challenge when it comes to meeting modern environmental standards while maintaining efficiency. This study is part of the more comprehensive research which aims to develop an expert system that utilizes existing measurements to estimate key parameters crucial for both energy production and pollution reduction. The focus is on Serbian thermal power plants, particularly plant Nikola Tesla unit B1. One of the critical parameters for optimizing thermal power plant control loops is the heating value of coal, which is challenging to measure in real time due to the coal's varying chemical compositions and caloric values. This paper examines 74 different parameters measured in 59 instances to estimate the hating value of coal at unit B1. Through detailed analysis and feature selection methods, including linear regression, this research aims to identify the most informative parameters for estimating the heating value of coal, which will improve the control system that enables more efficient and environmentally friendly power generation in coal fired thermal power plants. [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]

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 thermal effect of coal oxidation has a deep connection with the coal microstructure. A long flame coal, prone to spontaneous combustion is selected for the Differential scanning calorimetry (DSC) experiment and Fourier transform infrared experiment (FTIR) to identify the multi-scale thermal effects and mechanism of oxidized coal at different pre-oxidation temperatures. A model of the relationship between macro thermal effect and microstructure during coal oxidation is established by adopting multiple linear regression. It indicated that, with the increase of pre-oxidation temperature, the oxidizing property and exothermic of oxidized coal first decrease and then increase. The FTIR illustrated that the intramolecular hydrogen bond and free and linked hydrogen bond in the hydroxyl group have multiple collinearities. The result showed that the coal oxidation process is divided into three stages. In the heat absorption stage, aliphatic hydrocarbons and C=C double bond are negatively correlated with the exothermic rate. In the slow heat release stage, the variance predicted by the regression model is 0.722, which characterizes and predicts the degree of coal spontaneous combustion. In the heat release stage, the key factors affecting the heat release rate are aliphatic hydrocarbons and carboxyl groups, and the amount of heat release increases exponentially. [ABSTRACT FROM AUTHOR]

The two categories of metallurgical coal are coal for coking and pulverized coal for injection in blast furnaces. The most significant characteristics of coking coal are those determined by technical analysis (yield of volatiles, ash content, etc.) and the metallurgical properties determining the quality of blast furnace coke. For pulverized coal, the important parameters are those determined by technical analysis, the calorific value, and the grinding index. Demand for metallurgical coal depends on the output of pig iron, which, in turn, depends on regional characteristics. Even in the era of the green agenda, metallurgical coal retains its benefits. Increase in the supply of metallurgical coal may be expected to continue until 2030. Most such coal comes from Australia, Russia, and Mongolia. In Russia, several large coal projects are underway (ELSI, Kolmar, Severnaya Zvezda). The goal is to export the coal, especially to Asia. Russian exports will increase by 20 million t per year in the near future, according to the authors' predictions. Global coal prices depend on production costs, which are at historically high levels. If global prices fall, the market will respond speedily, as high-cost suppliers are driven from the market, restricting supply, and global prices rise again. [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]

The topic of waste incineration/co-incineration is critical, given the increasingly stringent regulations on environmental aspects. The widespread use of polymeric materials generates significant waste, posing an ecological problem. Current regulations mandate a reduction in the landfilling of plastic waste, which should be replaced by recycling, with the possibility of exploiting the energy potential due to its high calorific value. The electricity generation in Poland is mainly based on coal, so using polymers as alternative fuels is an important research issue. The research results presented in this paper make it possible to compare the properties of selected waste plastics and coal and their behavior during thermal processes, considering the quality of the gases released. Based on the thermal analyses, a FuzzyTherm model was introduced based on one of the fuzzy logic methods, one of the main artificial intelligence modeling approaches. The model predicts the temperatures corresponding to endothermic and exothermic reactions. The model achieved good accuracy. The maximum relative error between measured and calculated data is lower than 11%. These aspects constitute an innovative element of this paper. [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]

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]

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]