Coal Technology Research Articles

Physical properties and hydration behaviors of paste casting brick containing coal gasification slag (CGS): Effect of curing condition and CGS dosage

In the process of developing coal chemical technologies, it is necessary to address environmental pollution and resource waste caused by the associated solid waste coal gasification slag (CGS). This study investigated the feasibility of using CGS as a substitute for fly ash (FA) in the preparation of paste casting bricks. The effects of curing conditions and CGS dosages on the physical properties of the specimens were investigated and related to the hydration behaviors through various microscopic techniques. The results showed that the occurrence of electrostatic flocculation and the enrichment of active substances increased the yield stress of the slurry as the CGS replacement rose, which manifested as decreased fluidity at the macroscopic level. The secondary hydration reaction was facilitated with the increased CGS replacement rate due to the desirable hydraulic activity of CGS. XRD, FTIR and TG results corroborated that the content of hydration products which contributed to strength development were enhanced with the addition of CGS under different curing conditions. XRD and SEM-EDS results indicated that the doping of elements such as Mg and Al under autoclaved condition led to a reduction in the grain size of tobermorite, and the micro-morphology tended to concentrate stresses under pressure. The results of this study promote the resourceful utilization of CGS in building materials and lay the foundation for further scale-up industrial application.

Applicability of blue algae as an activator for microbial enhanced coal bed methane technologies

The blue algae can be used as a nitrogen agent for promoting biological coalbed methane, but its applicability and microbial mechanism in different microbial enhanced coalbed methane technologies kept unknown. This study evaluated the methanogenic efficiency of blue algae addition with a mass ratio of 10% under fermentative degradation and microbial electrolytic cell technologies, and studied the changes of coal microstructure, surface functional groups, organic components and microbiome. The results showed that the algae addition affected the micro-concave-convex structure, non-uniform distribution of micro-particles and micro-cracks of coals, and finally increased the methanogenic rate by 1.74–2.66 times. The algae addition mainly affected the coal organic components including hydroxyl structure, hydrocarbon structure, aliphatic oxygen-containing functional groups and aromatic structure, as well increased the humus acids and microbial metabolites in fermentation broth; among them, the increased metabolites showed great differences between different technologies. The algae addition mainly increased the genera belonging to phylum Bacillota (such as Bacillus and Clostridium) and methanogens (Methanosarcina and Methanoculleus). These Bacillota groups could degrade organic matter into acetate and methanol via pathways of glycolysis and benzoate degradation, which provided substrates for such methanogens. This study strengthened the effectiveness of blue algae in enhancing technologies for biological coalbed methane.

Reconfiguration of acid gas removal process matching the integration of coal chemical industry with green hydrogen

The focus of the acid gas removal process has shifted from decarbonization and desulfurization to desulfurization in the context of integrating coal chemical technology with green H2 without a water gas shift unit. The conventional Rectisol process, Selexol process, organic amine process, and sulfone-amine process have been reconfigured to form the R-Rectisol process, R-Selexol process, R-MDEA process, and R-Sulfolane-MDEA process to adapt to the shift of acid gas removal target. The removal efficiency of H2S and CO2, process energy consumption, and process cost are investigated to evaluate the technical and economic performance of the above four reconfigured acid gas removal processes. The results indicate that for the R-Recitsol process and R-Selexol process, both high pressure and low temperature increase the relative selectivity of H2S to CO2, thereby enhancing the selective removal of H2S. In contrast, for the R-MDEA process and R-Sulfolane-MDEA process, low pressure and low temperature improve the relative selectivity of H2S to CO2, thereby facilitating the selective removal of H2S. Under optimal operating conditions, the value of relative selectivity of H2S to CO2 of the R-Sulfolane-MDEA process is the largest, and the relative selectivity of H2S to CO2 of the R-Rectisol process, R-Selexol process and R-MDEA process are only 7.64 %, 12.85 %, and 68.40 % of the relative selectivity of H2S to CO2 of the R-Sulfolane-MDEA process, respectively. Compared to the other three reconfigured acid gas removal processes, the R-Sulfolane-MDEA process demonstrates superior advantages in both energy consumption and economic feasibility, provided that the H2S levels remain below 0.1 ppm in purified syngas. This study aims to enhance the decision-making process for gas purification methods in the coal chemical industry by considering integrated green H2 as an alternative to the water gas shift unit.

Innovative solid waste backfilling technology for top coal caving mining: analysing top coal movement and recovery optimisation

ABSTRACT The study introduces a novel solid backfilling technology, aiming to address gangue accumulation problem in top coal caving mining. To reveal its top coal drawing mechanism, discrete physical and numerical models were established. During the initial drawing stage, considerable amounts of low-position top coal are extracted, with yields fluctuating. As the working face advances, the drawing body shape shifts from knife-handle to semi-arch, and coal-gangue boundary curvature varies periodically. At low backfilling ratios, premature gangue exposure causes the loss of high-position top coal. Conversely, higher backfilling ratios facilitate the creation of a reconstructed floor, thereby enhancing top coal recovery.

Analysis of difficult flotation mechanisms for coarse low-rank coal: Comparing fluidized-bed and mechanical flotation technologies

Efficient flotation of coarse low-rank coal is essential for enhancing energy utilization in the mineral processing industry. As the beneficiation equipment scales up, the precision of particle size classification before flotation decreases, leading to a higher coarse particle content in the feed, which poses significant challenges to traditional flotation processes. Recent advancements in fluidized bed flotation technology have demonstrated considerable advantages in the flotation of coarse-grained metallic minerals; however, its application to coarse low-rank coal remains relatively unexplored. This study investigates the potential of fluidized bed flotation technology for coarse low-rank coal, employing various analytical methods to elucidate difficult flotation mechanisms. Scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) were utilized to comprehensively characterize the surface morphology and chemical composition of coal samples. The influence of increasing particle size on flotation performance was systematically assessed through measurements of induction time and critical detachment amplitude. Comparative flotation experiments were conducted to evaluate the efficacy of traditional mechanical flotation against fluidized bed flotation technologies. Results indicate that the presence of cracks and oxygen-containing functional groups on the coal surface significantly enhances hydrophilicity, hindering flotation recovery rates. With increasing particle size, the induction time between particles and bubbles lengthens, while the critical detachment amplitude decreases, weakening the attachment and increasing detachment likelihood. Although high-efficiency collectors enhance coal particle hydrophobicity, they cannot fully mitigate the turbulence disrupting bubble-particle interactions in mechanical flotation. Conversely, fluidized bed flotation effectively minimizes turbulence interference, leading to an approximate 40 % increase in the recovery rate of coarse low-rank coal (0.25–1.00 mm) compared to traditional mechanical flotation. This study presents a novel technological approach for the efficient recovery of coarse low-rank coal, contributing to the clean utilization of low-rank coal resources.

Characteristic and mechanistic study of enhanced carbon-based synfuel from biomass and coal by magnetite additive for synergistic co-carbonization technology.

Biomass is a renewable and potentially carbon-neutral energy source and can be a promising alternative to fossil fuels in the ironmaking industry. The co-carbonization technology of biomass and coal for high-quality biofuel production has great potential. This study investigated the effects of the addition of magnetite (Fe3O4) on the physicochemical properties and combustion performance of wood shavings (WS) and bituminous coal (BC) (WS/BC = 4/6) sintered with a carbon-based synfuel. The results indicate that increasing the proportion of 2 wt.% Fe3O4 can increase the high calorific value to 34.60 MJ·kg-1 and the maximum combustion rate temperature reaches 469 °C, however, increasing the proportion decreases the burnout temperature to 575 °C, and the activation energy of the rapid pyrolysis stage decreases to 43.54 kJ·mol-1. In addition, the activation energies of WS/BC char in the fast co-pyrolysis stage and the combustion reaction decrease significantly to 43.54 kJ·mol-1 and 92.96 kJ·mol-1, respectively, with the addition of 2 wt.% Fe3O4. The area ratio of the fitted aromatic C−O reaches 79.91%. Fe3O4 can form active centers on the surface of a carbon-based synfuel, improving the stability and orderliness of the fuel. The catalysis of the Fe3O4 additive with macromolecular organic compounds involves mainly oxygen-containing functional groups, promoting the cleavage of C−C bonds connected to oxygen-containing functional groups. In general, these results provide certain theoretical guidance for the preparation and application of sintered carbon-based synfuels.

TO THE ISSUE OF NON-PROJECT FUEL COMBUSTION

Nowadays, the issues of ecology and sustainable development are becoming more and more urgent, and the scientific community is actively looking for ways to more efficient and environmentally friendly use of renewable energy sources. One of such directions is the development and improvement of coal combustion technologies in aerodynamic furnaces. This paper offers a detailed analysis of this topic, looking at both theoretical aspects and practical applications. Aerodynamic furnaces are specialised devices designed to burn solid fuels such as coal with maximum efficiency and minimum environmental impact. The basic principle of operation of such furnaces is to create optimum conditions for complete combustion of the fuel, which is achieved through carefully designed aerodynamics and process control. The operation of the boiler on the coal of Karazhyra deposit is considered. This coal belongs to non-project fuel and improvement of its combustion processes is required to reduce harmful emissions and increase combustion efficiency. For the energy sector of the Republic of Kazakhstan, the conducted research is important, and the results obtained can be used to regulate and improve the operation of similar equipment, which contributes to improving environmental performance and overall efficiency of the country's energy systems.

Rapid multispectral image identification of coal and gangue based on super-resolution reconstruction

Accurate coal and gangue separation is crucial for efficient coal utilization. Multispectral imaging (MSI) offers a promising approach but often suffers from limited resolution, hindering accurate identification. This study proposes, a novel method, to our knowledge, combining super-resolution (SR) reconstruction and machine learning to enhance coal and gangue identification in MSI. A spectral attention mechanism and an enhanced multi-scale residual network with GAN (SAM-EMSR-GAN) were developed and evaluated alongside four established SR methods: SRCNN, VDSR, ESRGAN, and DRMSFFN. MSI images of 300 coal and 300 gangue samples were reconstructed, using each method to compare their performance. SAM-EMSR-GAN achieved superior reconstruction, attaining the highest structural similarity index (SSIM) of 0.906 and peak signal-to-noise ratio (PSNR) of 32.97 at 4× magnification. The study further investigated the combination of the SR method with seven widely used classification models: CatBoost, random forest (RF), support vector machine (SVM), least squares support vector machines (LSSVMs), eXtreme gradient boosting (XGBoost), ResNet50, and ResNet101. CatBoost consistently delivered the highest classification accuracy across all SR methods, reaching 97.32% accuracy at 959.37 nm when paired with SAM-EMSR-GAN. Independent validation using a separate dataset confirmed the robustness of this approach, achieving a 92.49% accuracy. These findings demonstrate the potential of combining SAM-EMSR-GAN and CatBoost for accurate and efficient coal and gangue identification, paving the way for intelligent and automated coal sorting technologies.

Effect of the main components in gasification wastewater on the surface properties of coal water slurry

AbstractCoal water slurry is an advanced and efficient clean coal technology; using gasification wastewater to prepare coal water slurry can recycle wastewater and improve energy utilization efficiency. As the complex substances in wastewater have a great influence on the slurry properties, the effects of organic matter, metal ions, and ammonia nitrogen in gasification wastewater on the surface properties of coal water slurry are studied in this paper in order to provide new ideas for slurry mechanism of coal water slurry prepared from wastewater. Results show the following: (a) Compared with ordinary coal water slurry, the concentration of coal water slurry prepared from wastewater with high organic content increased by 2.9%, while the concentration of coal water slurry prepared from wastewater with high ammonia nitrogen content decreased by 2.1%. (b) The contact angles of coal water slurry prepared with phenols, alcohols, and urethane are reduced by 2.8°, 6.3°, and 1.5°, respectively, so organic matter can change the hydrophilicity of coal particles and affect slurryability. (c) Mg2+ and Ca2+ have basically no effect on slurry. Fe3+ reduces the absolute value of Zeta potential by 33.1, and Cu3+ increases that by 22.8, as they affect the slurryability by changing the surface potential of coal particles and the absorption of additives. (d) Ammonia nitrogen influences the slurryability by changing the pH value of the slurry. The conclusion of the influence mechanism of organic matter, metal ions, and ammonia nitrogen in wastewater on slurryability can provide a technical reference for the selection of suitable wastewater to prepare coal water slurry.

The Effect of CO on the Exothermic Characteristics of Low-Temperature Oxidation in Coal

ABSTRACT In recent years, abnormally high concentrations of CO gas have often been detected in goaf areas of coal mines in China, which have posed a serious threat to safe production in coal mines and the life and safety of underground personnel. The effect of CO on the exothermic characteristics of low-temperature oxidation in coal was studied by analyzing the exothermic characteristics, heat release, oxidation stages, and activation energy of coal at different CO concentrations using a C600 microcalorimeter. The experimental results indicated that CO promoted the coal oxidation at low temperature, but inhibited it after reaching 144°C. When the CO concentration is 30%, the exothermic characteristics of coal in low-temperature oxidation adsorption stage were significantly affected, with the heat flow value decreased by 27.0% and the initial exothermic temperature point moved forward by 3.9 K. In the later stage of the oxidation reaction, the heat release of coal was linearly negatively correlated with CO concentration. The higher the concentration, the lower the heat release. These findings contribute to understanding the combustion mechanism of coal in high-concentration CO atmosphere and provide valuable insights for designing and optimizing coal utilization technologies.

Hydrogeochemical evolution patterns of diverse water bodies in mining area driven by large-scale open-pit combined underground mining-taking Pingshuo Mining Area as an example

Large-scale open-pit combined underground mining activities (OUM) not only reshape the original topography, geomorphology, and hydrogeochemical environment of the mining area, but also alter the regional water cycle conditions. However, due to the complexity arising from the coexistence of two coal mining technologies (open-pit and underground mining), the hydrological environmental effects remain unclear. Here, we selected the Pingshuo Mining Area in China, one of the most modernized open-pit combined underground mining regions, as the focus of our research. We comprehensively employed mathematical statistics, Piper diagram, Gibbs model, ion combination ratio, principal component analysis and other methods to compare the hydrochemistry and isotope data of different water bodies before (2006) and after (2021) large-scale mining. The changing patterns of hydrochemical characteristics of different water bodies and their main controlling factors in mining area driven by OUM were analyzed and identified, revealing the water circulation mechanism under the background of long-term coal mining. The results showed that: (1) The chemical composition of water has changed greatly due to large-scale coal mining. The hydrochemical types of Quaternary and Permian-Carboniferous aquifers shifted from predominantly HCO3-Ca·Mg before intensive mining to primarily HCO3·SO4-Ca·Mg, HCO3-Na, HCO3·SO4-Na·Mg, and HCO3·SO4-Ca·Mg, HCO3-Ca·Na, HCO3·SO4-Mg·Ca post-mining. Variations in the hydrochemical types of surface water were found to be complex and diverse. (2) Coal mining activities promote the dissolution of silicate rock and sodium-bearing evaporites, enhancing the strength and scale of positive alternating adsorption of cations. The oxidation of pyrite, dissolution of silicate weathering, and the leaching of coal gangue were identified as the main reasons for the significant increase of SO42−, while decarbonation in confined aquifers led to a decrease in HCO3−. (3) Results from the principal component analysis and stable isotopes demonstrated the hydraulic connection among surface water, Quaternary aquifers, and Permian-Carboniferous aquifers induced by long-term OUM. The research findings provide a reference basis for the coordinated development of coal and water in the Pingshuo Mining Area and other open-pit combined underground mining areas.

Classification of coal gangue and identification of coal type based on first-derivative of mid-infrared spectrum

Efficiently sorting coal gangue and identifying coal types are vital operations in coal preparation, yet they are traditionally resource-consuming, labor-intensive, and potentially hazardous. This work puts forward an straightforward method employing mid-infrared spectroscopy with first derivative spectrum to address these issues. The proposed technique focuses on the delineation and enhancement of characteristic spectra to detect subtle differences among samples. The method utilizes just a few characteristic spectra of 3740–3700 cm−1, 1790–1750 cm−1, 1615–1583 cm−1, 1580–1540 cm−1, 1550–1440 cm−1, 1270–1210 cm−1 and 867–854 cm−1 to achieve 100 % high-accuracy classification of coal gangue and identification of coal types with total 250 spectra, such as bituminite, anthracite, lignite, roof sandstone and gangue, without the need for secondary sample processing or the assistance of machine learning algorithms, simplifying the process considerably. Such a strategy not only significantly improves the efficiency of coal sorting but also endorses real-time on-site detection. It offers a theoretical foundation for advanced coal separation technology and its implementation in real-world mining operations.

Ripple effects of coal phaseout on employment in China: From mining to coal consumption sectors

China's stringent decarbonisation, marked by an uncompromising coal phaseout, has induced significant ripple effects across the coal industry chain's employment structure. By utilising a composite methodology that integrates the Global Change Assessment Model and Input‒Output Model, this study systematically quantifies the impact on employment, revealing a loss of 1.6 million jobs in mining and 8.2 million in the entire chain. Concurrently, a labour shift to the renewable sector has resulted in an 18.5% increase in employment, equivalent to creating 508,000 new positions from 2017 to 2020. Projections suggest that renewable energy initiatives could address 25% of the employment gap for precision by 2060 under carbon neutrality scenarios. Nonetheless, the coal sector is expected to lose more than 20 million jobs, indicating the need for a 2.3 trillion-yuan compensation fund. This study highlights the need for policy interventions to facilitate labour transitions through comprehensive retraining programs and strategic investments. Promoting economic diversification and clean coal technologies can improve resource utilization and create new jobs. Additionally, repurposing abandoned coal mines into energy storage facilities or renewable energy sites can prevent stranded assets and generate employment. These findings provide a robust framework for addressing the socioeconomic challenges of energy transitions, offering critical insights for other coal-dependent countries aiming for sustainable development.

Examination of the use of binderless zeolite blend as backfill materials to enhance CO2 adsorption in coal mine working face

The release and accumulation of CO2 in the working face of the coal mine is a major safety concern and requires an effective means to avoid the incidence of the mine. This present study therefore sought to develop a self-CO2 adsorbing backfill (SCAB) material to remove CO2 from the working environment, and simultaneously mitigate the movements of the surrounding rock layers. SCAB was formulated using coal mine solid waste activated with an alkali activator, and binderless 4 A zeolite was embedded in the backfill body. The total CO2 adsorption capacity was investigated using a CO2 flow-through method under ambient pressure and temperature conditions. The adsorption plateau was found in stages II and III respecting the predetermined curing time and zeolite contents. The maximum adsorption capacity was 143.8 mg-CO2/g-SCAB, resulting in an increase of up to 82 % in UCS compared to reference samples. The underlying mechanism was discovered in morphological analyses.1) The well distribution of zeolite in the SCAB body provided as diffusive pathways and adsorption sites for CO2 after standard curing. 2) The adsorbed CO2 underwent a desorption stage when the CO2 concentration decreased and reacted to the cementitious matrix of the SCAB body. 3) More CaCO3 crystals were generated and filled in the micro spaces of the SCAB body, which contributed to an increase in compressive strength. This study developed an effective approach to remove CO2 gas from the working face of the coal mine during backfilling. Adsorbed CO2 improved the strength of the material, provided as a novel multi-function backfill mining for sustainable green coal mining technology.

Development of a limestone-based ballasted material for enhanced co-removal of turbidity and fluoride from coal mine water: An efficacy study

The rapid progression of coal mining technology in recent years has resulted to the discharge of mine water with excessively high levels of turbidity and fluoride, presenting a complex contamination issue. This study develop an innovative limestone-based ballasted material, integrating it with ballasted flocculation technology. The synergistic effects of surface flocculation and adsorption have enabled the simultaneous and efficient removal of high concentrations of turbidity and fluoride. The influence of various parameters, including the dosage of the coagulant, flocculant, ballasted material, and the stability under long-term continuous operation, on the performance of this new technology was investigated. Findings indicate that an increase in the dosage of the coagulant, polyaluminum chloride (PAC), positively affects the removal of turbidity and fluoride ions, with an optimal dosage of 60 mg/L. The addition of polyacrylamide (PAM) showed that both conventional and ballasted coagulation techniques exhibit an initial increase followed by a decrease in turbidity removal efficiency, and an ascending trend in fluoride removal efficiency, with an optimal PAM dosage of 1.0 mg/L. The dosage of the new ballasted material was determined based on the initial water turbidity and fluoride concentrations, an increase in its dosage led to a progressive reduction in effluent turbidity and a corresponding increase in fluoride removal. A 30-day continuous operation confirmed the stability of the new process, with a treatment cost of approximately 2.67 $/t. The pseudo-first-order kinetic model and the Langmuir adsorption isotherm equation provided satisfactory fits to the treatment data, suggesting that both conventional and ballasted coagulation involve a combination of surface adsorption and intraparticle diffusion mechanisms for the removal of turbidity and fluoride.

Research on the Optimization and Application of New Energy Technologies in Clean Coal Conversion

With the continuous growth of global energy demand and increasingly severe environmental issues, clean coal technology has garnered significant attention as a crucial means to mitigate the negative environmental impacts of coal utilization. However, traditional clean coal conversion technologies often suffer from low energy utilization efficiency and insufficient environmental pollution control. In recent years, the application of new energy technologies in the clean coal conversion process has shown tremendous potential, significantly optimizing energy conversion efficiency, reducing emissions, and enhancing economic benefits. This paper systematically explores the application of solar energy, wind energy, and biomass energy in clean coal conversion, analyzes the mechanisms and methods through which new energy technologies optimize the clean coal conversion process, and proposes future research directions and policy recommendations.

Key SDG7 Factors Shaping the Future of Clean Coal Technologies: Analysis of Trends and Prospects in Poland

This article presents the results of an analysis aimed at verifying the relationship between the implementation of SDG Goal 7 and the use of clean coal technologies in Poland. Clean coal technologies in the United Nations plans will constitute a crucial element of the strategy for sustainable development in the energy context. They are intended to be one of the tools for building an energy system based on renewable energy sources, constituting a bridge that enables the transition of Poland’s energy system from coal to renewable energy sources. To identify whether this relationship exists, the Autoregressive Moving Average with Exogenous Input (ARMAX) model was used. The structure of the model, its correctness, and its accuracy were confirmed using information criteria; statistical tests such as Dickey-Fuller, Doornik-Hansen, Durbin-Watson, and Breusch-Pagan; and measures of prediction accuracy such as MAPE, MAE, and RMSE. The explanatory variables were the Objective 7 indicators adopted by Eurostat. Before being introduced to the ARMAX model, they were standardized using the Compound Annual Growth Rate (CAGR) indicator. The analysis made it possible to indicate which of the explanatory variables has the greatest impact on the development of clean coal technologies in Poland, to determine a synthetic CAGR measure for all the explanatory variables, and to compare the results obtained with the indicator determined by the United Nations.

Pore evolution and reaction mechanism of coal under the combination of chemical activation and autothermal oxidation

Aiming at the limitation problems such as limited scope, high cost and energy consumption of coal bed penetration enhancement technology by traditional physical and chemical methods, a coal seam methane penetration enhancement method based on the combined action of chemical activation and auto thermal oxidation is proposed from the idea of utilizing the in-situ energy of the coal body. In this paper, N2 and CO2 adsorption, XPS and FTIR methods are used to study the pore structure evolution law and the change characteristics of the reactive structure of coal matrix under the effect of chemically activated autothermal oxidation. The synergistic microporous pore volume of chemical activation and auto thermal oxidation was 48.91 cm3/g−1 × 10-3, which was 28.96 % and 22.7 % higher than chemical activation and auto thermal oxidation respectively; The microporous specific surface area was 162.7 m2/g, which was 38 % and 26.6 % higher than chemical activation and auto thermal oxidation respectively. Activated coals expand and merge holes to a deeper degree after oxidative warming, and the complexity of the pore structure in the coal decreases; Highly reactive radicals in coal pores substantially promote the oxidation of coal structure, enhance the aromatic polymerization reaction of activated coal, and improve the maturity and aromaticity of activated coal, and the oxygen-containing functional groups in activated coal are negatively correlated with the oxidation temperature. The results of this study reveal the potential of the auto thermal oxidation-driven penetration enhancement method under chemical activation for coal seam gas penetration enhancement and extraction.

Characterization of energy-driven damage mechanism and gas seepage in coal under mining-induced stress conditions

Gas seepage and progressive failure of coal are common energy-driven mining phenomena. A comprehensive understanding of the energy-driving mechanism behind the catastrophic behavior of mining-induced coal is fundamental to innovating the technology of coal and gas co-mining. Thus, this study simulated three typical mining stress evolution process in protective coal-seam mining (PCM), top-coal caving mining (TCM), and non-pillar mining (NM) to investigate the energy evolution and distribution patterns of coal. The results indicate a strong correlation between energy dissipation and gas seepage. By transitioning from PCM and TCM to NM, the peak elastic strain energy of gas-bearing coal increased by 155.92 %, and the ratio of peak dissipative energy decreased from 51 % to 41 %. Under the PCM stress path, gas seepage decreased the energy storage by 13.52 %, whereas the pre-mining pressure relief and enhanced permeability simulation increased in peak dissipation energy by 49.66 %. Using the cumulative dissipative energy as a damage variable reveals that the degree of coal damage evolution under PCM is higher than other mining methods. Based on the energy-driven damage mechanism, a new coal permeability model was established, and its comparison with classical permeability model demonstrated its excellent fitting effectiveness.

Exploring the Potential of Microbial Coalbed Methane for Sustainable Energy Development.

By allowing coal to be converted by microorganisms into products like methane, hydrogen, methanol, ethanol, and other products, current coal deposits can be used effectively, cleanly, and sustainably. The intricacies of in situ microbial coal degradation must be understood in order to develop innovative energy production strategies and economically viable industrial microbial mining. This review covers various forms of conversion (such as the use of MECoM, which converts coal into hydrogen), stresses, and in situ use. There is ongoing discussion regarding the effectiveness of field-scale pilot testing when translated to commercial production. Assessing the applicability and long-term viability of MECoM technology will require addressing these knowledge gaps. Developing suitable nutrition plans and utilizing lab-generated data in the field are examples of this. Also, we recommend directions for future study to maximize methane production from coal. Microbial coal conversion technology needs to be successful in order to be resolved and to be a viable, sustainable energy source.