Anthracite Research Articles

Molecular simulations of hydrogen adsorption on coal with different ranks: Implications for hydrogen geo-storage

Underground hydrogen storage is a promising solution for the safe and efficient storage of industrial-scale H2. In this study, the adsorption behaviors of H2 in coal with different ranks under various temperatures and pressures are investigated using molecular simulations. It is found that the H2 adsorption capacity is positively correlated with coal rank, which is mainly attributed to the combined effects of surface chemical property and pore structure. Moreover, the isosteric heat of adsorption of H2 increases with the reduction in pore size due to the overlap of potential energy. In addition, the absolute adsorption amount of H2 in moist coal generally decreases with the increase in moisture content because of the competitive adsorption between water and H2 and the spatial occupation of water clusters/bridges. As a result, the anthracite coal seam with abundant micropores and few hydrophilic groups is considered to have a high potential for H2 storage.

Hard coal production in Poland in the aspect of climate and energy policy of the European Union and the war in Ukraine. Investment case study

The adoption by European Union (EU) member states of a long-term vision to move toward climate neutrality implies abandoning hard coal production, temporarily using natural gas and transitioning to renewable energy and nuclear power. Along these lines, most EU countries have ceased coal production, but coal consumption has declined at a much slower rate, resulting in increased dependence on coal imports, including from Russia. In 2021, as much as 51 million tons of coal went from this country to EU countries. In 2022, in the wake of Russia's aggression against Ukraine, resulting in an embargo on Russian coal, some EU countries, mainly Poland, began to consider extending the operation of coal mines and making investments in maintaining or increasing capacity, to make up for the shortage of coal mainly for residential customers. Deciding to make such an investment is difficult, among other things because of the accompanying business risks, which the mine's management is responsible for exceeding. The publication presents a developed model for assessing the business risk of investment in maintaining or increasing coal production, the use of which makes it possible to obtain information to support rational decision-making.

Geochemistry of the Leatherwood coal in eastern Kentucky with an emphasis on enrichment and modes of occurrence of rare earth elements

The Middle Pennsylvanian (Bolsovian) Leatherwood coal in the central part of eastern Kentucky is a moderately thick, moderate-S seam that has been one of the major energy resources in the region. Much of the seam profile consists of clarain, dull clarain, and durain with some brighter lithologies at the base of the seam and in the upper portion of the coal at one site. A previous study emphasized petrographic trends. In this investigation, the geochemistry of the coal is examined. Some elements, such as Ge and Ga, are enriched at 2× and 5× the World hard coal averages in the coal lithotypes adjacent to rock (roof, floor, partings). Arsenic and other chalcophile elements (Zn, Co, Ni) tend to be concentrated at the top and bottom of the seam profiles and below partings, generally in the coals with the highest pyritic sulfur content. Manganese enrichments occur in bright clarain lithologies at one site. No coal lithology reaches a 5× the World hard coal average, but samples between the 2× and 5× World hard coal averages tend to be at the top and bottom of the coal seam. Most coal samples tend to have a light rare earth element (LREE) enrichment. The basal lithotype at all sites, though, has a heavy REE enrichment and, via inference from the Zr and TiO2 concentrations, a smaller influx of detrital minerals than the basal lithotypes in many Appalachian coals. While the nature of REE associations is complicated by the high volatile A bituminous coal rank, the relatively high concentrations of the heavy REE suggest an original, albeit possibly not exclusive, organic association for those elements.

Groundwater vulnerability to pollution in degraded coal mining areas: modifying the DRASTIC method using the factor of exploitation impact on land surface

Mining activities such as underground exploitation of hard coal deposits and open cast mining are strong factors on groundwater depending on mine life cycle phases. The impact of coal mining activities on groundwater have been reported from many countries. In this case, a vulnerability assessment was conducted base on standard DRASTIC method and its modification DRASTIC MINE (DRASTICM) method. In order to take into account, the impact of mining activities, a new parameter was added which defined the impact of coal seams on the rock mass above, including the degree of its drainage and the range of its impact. In the standard DRASTIC method, the results indicate that groundwater vulnerability with high (38.6%) and very high occurrence classes (16.9% of the area), mostly covers the central part of the cast mine. In contrast, the reclaimed area of the excavation is a low-class area. The DRASTICM method increased the vulnerability index from 3 to 24 on 95% of the area, so a new vulnerability class of extremely high was delineated, which occurred in 1.6% of the area. This indicates areas that should be treated as a priority in order to avoid pollution, and in the final stage to plan activities in the field of the reclamation of mining areas. The results showed that groundwater vulnerability assessment in coal mining areas can be significantly improved.

An Economic Evaluation of the Functioning of Hard Coal Mining in Poland in the Years 2016-2018

An Economic Evaluation of the Functioning of Hard Coal Mining in Poland in the Years 2016-2018

Criteria for Assessing the Longevity of Hard Coal Mines

Criteria for Assessing the Longevity of Hard Coal Mines

Assessment of the Impact of a Municipal Landfill on Microbiological Quality of Air in the Revitalized Area of “Brzeszcze Wschód” Hard Coal Mine

Assessment of the Impact of a Municipal Landfill on Microbiological Quality of Air in the Revitalized Area of “Brzeszcze Wschód” Hard Coal Mine

NANOSTRUCTURED COMPOSITES BASED ON MATRICES OBTAINED FROM COAL RAW MATERIALS FOR DEVELOPMENT OF ELECTRODE MATERIALS FOR SUPERCAPACITORS

The article reports the results of the study of the morphology, porous structure and electrical capacitance characteristics of highly porous carbon matrices (HPCMs) obtained from coal raw materials with different degrees of metamorphism and nanostructured composites (NSCs) based on them, the surface of which is decorated with gold or manganese oxide nanosized particles (NP), accumulating electrical charge during polarization in the electrolyte via two mechanisms (formation of an electrical double layer (EDL) and involvement of pseudo-capacitance component during Red-Ox reactions on electrodes). The samples of HPCMs were obtained by high-temperature (800 °C) alkaline activation (the mass ratio KOH/C = 2 : 1) of fossil coal from the coal basins of the Kemerovo Region and the Republic of Sakha (Yakutia): CAK - based on anthracite of the Kiyzasskiy open-pit mine (Kuzbass), with the highest coalification degree; CBK - based on boghead (a kind of sapropel coal ) from the Taymylyr deposit (Yakutia) with the lowest degree of metamorphism; CDK - based on long-flame coal (Kuzbass) occupying an intermediate position in the metamorphism series. Results obtained by scanning electron microscopy, small-angle X-ray scattering in combination with sorptometry showed that the NSC morphology is largely determined (except for submicron aggregates) by the porous structure of the matrices. The shape of cyclic voltammetry (CVA) curves for HPCMs CDK, CBK and Au-NP filled NSC based on them indicated a significant contribution from EDL into capacitance; the contribution of pseudo-capacitance is observed for the composite MnOx/CDK electrode. The features of CVA curves for microporous CAK HPCM and NSC based on it are probably caused by hindered diffusion. The specific electrical capacitance is higher as a result of the polarization of CDK and CBK HPCM with large proportions of mesopores, as well as NSCs on their basis, than that resulting from the polarization of microporous CAK and the corresponding composites. For all three HPCMs, the introduction of fillers causes an increase in the electrode capacitance. The effect is more significant for NSCs obtained from hard coals with a low level of metamorphism (an increase up to 1.8 and 1.6 times with respect to the capacitance of initial matrices for NSCs based on CDK and CBK, respectively, according to the impedance measurement data), which is due to a decrease in the active resistance and the charge transfer resistance of the cells, and, in general, to the active component of the impedance.

Influence of method for determining thermal conductivity of coal combustion products on calculation accuracy

The determination of thermal conductivity of the combustion products of coal of various compositions by a simplified method and in accordance with the molecular-kinetic theory according to the Masson – Saxena equation is considered. Calculations were made for hard coal of the Volodarsky mine of grade A, Donetsk basin of grade OS, Kuznetsk basin of grade K, Tallinn section of grade G, Kizelovsky basin of grade G, and Tulganskoye deposit of grade 1B with the content of the combustible part by weight from 70.8% to 25.1%. The temperature of the combustion products varied from 200°C to 400°C in increments of 50°C, and the excess air coefficient varied from α = 1.15 to α = 1.5 in increments of 0.05. The discrepancy between the results of the simplified calculation and the results obtained by the Masson – Saxena equation was estimated using the relative error. Analysis of the calculation results showed that the thermal conductivity coefficient calculated according to the additivity rule using volume and mass fractions of the components of the combustion products is higher than that calculated using the Masson – Saxena equation at any excess air coefficients and temperature of the combustion products. With an increase in the temperature of the combustion products, in both cases, the error in determining the thermal conductivity decreases due to an increase in the value of the thermal conductivity. The use of simplified calculation methods leads to an increase in the thermal conductivity of combustion products by an average of 7.5% – 2% for coal of various compositions, depending on the temperature of the combustion products, compared with the values calculated using the Masson – Saxena equation.

Life cycle assessment of the manufacturing and operation of distillation column for eliminating volatile and organic halogen compounds from process wastewater

Distillation serves as the foremost method for commercial-scale separation of fluid mixtures. Widely applied in wastewater treatment, it is the preferred choice for isolating volatile multi-component mixtures into pure substances. Distillation technology offers notable economic benefits due to its easy implementation, high efficiency, productivity, and robust safety features. This study examines the environmental impacts associated with the production and usage of a distillation, specifically in treating pharmaceutical process wastewater containing organic halogen compounds (AOX). The analysis adopts a 'gate-to-gate' approach, with the specified functional unit (FU) set at 1 kg of treated effluent containing no more than 8 ppm of AOX and less than 1000 mg O2/L of Chemical Oxygen Demand (COD). In this work, Life Cycle Assessment (LCA) is conducted using Product Environmental Footprint (PEF) and Recipe 2016 Endpoint (H) V1.06 methodologies, utilizing the SimaPro V9.3.0.3 software in conjunction with the Ecoinvent V3.8 database. Analysis results have shown the emission of 1.11 × 10–2 kg CO2-eq, in which operational and production processes contribute 91.9% and 8.1%, respectively. To mitigate adverse effects, alternative energy sources, i.e., solar, offshore wind, and onshore wind are integrated into the distillation procedure. The substitution of hard coal with solar, offshore wind, and onshore wind energy displays the potential to significantly reduce climate change impact by 64.3%, 62.9%, and 62.8%, respectively.Article HighlightsDistillation process undergoes a thorough life cycle assessment from production to application.Distillation process requires high energy and emits 1.11 × 10–2 kg CO2-eq per functional unit.The operational phase dominates over 90% in three damage categories: human health, ecosystems, and resources.

Life cycle analysis and economic evaluation of adsorptive removal of arsenic from groundwater using GAC and GAC-Fe adsorbents

The potential health effects associated with consumption of arsenic contaminated water have motivated chemical and energy intensive treatment processes. Granulated activated carbon (GAC) and iron impregnated granular activated carbon (GAC-Fe) are the two adsorbents which have shown significant removal of arsenic (As(V)). However, the synthesis of different adsorbents involves significant different materials and energy interactions which have different environmental and economic burdens. This study evaluates and compares the environmental impacts arising from treatment of arsenic containing water using GAC and GAC-Fe adsorbents, for the selection of more suitable one. The life cycle inventory pertaining to treatment through two adsorbents was prepared based on the data available in literature. The impacts were assessed utilizing ‘Sphera LCA for experts’ software with three midpoint methods i.e. CML 2001, TRACI 2.1 and ReCiPe 2016. Results show that chemically treated/impregnated adsorbents for arsenic contaminated water treatment not only have lesser environmental emissions but also reduces the treatment cost. The treatment with GAC-Fe has ∼30% lower impacts in GWP, AP, EP, MAETP, FAETP, ODP, ADP (E) and HTP categories than treatment with GAC, since increase in adsorbent's specific uptake in GAC-Fe reduces the amount of total adsorbent requirement. GAC-Fe based water treatment costs ∼23% less than with GAC. The main responsible parameters for emissions are synthesis of GAC from hard coal precursor, and electricity consumption in carbonization and drying operations. Apart from this, in case of GAC-Fe, additional impregnation and drying operation also contributes to emissions. The utilization of coke oven gas generated in adsorbent synthesis for energy credits has potentially reduced the emissions and operating cost. The less standard deviation (<10%) in Monte Carlo (MC) uncertainty analysis, indicated the reliability and robustness of LCA impacts. This study exemplified the environment friendliness of metal impregnated GAC based arsenic contaminated water treatment.

Organic pollutants removal from petroleum refinery effluents through adsorption using anthracite coal: Kinetics, Isotherms, and Thermodynamic Modeling

Organic pollutants removal from petroleum refinery effluents through adsorption using anthracite coal: Kinetics, Isotherms, and Thermodynamic Modeling

An attempt to use machine learning algorithms to predict strong tremors during longwall mining of a coal seam

Strong tremors during longwall mining are usually associated with the fracturing of thick sandstone layers. The prediction of such tremors is important and can be treated as a form of rockburst prevention. The article presents the possibility of predicting the occurrence of strong tremors based on the random forest algorithm in the 48-h forecast horizon. The study concerns a longwall panel in coal seam No. 506 in one of the hard coal mines in the Upper Silesian Coal Basin, Poland. The extraction of this longwall panel was carried out at a great depth, surrounded by thick layers of sandstone and with the occurrence of edges in the previously mined seams. Therefore, seismic activity was high and strong tremors occurred. Based on the seismic catalogue and data related to the longwall face advance, 12 parameters were selected that were most significantly positively or negatively correlated with the occurrence of strong tremors. Based on 10 randomly selected datasets, models of the random forest algorithm were trained and then tested. Due to the much smaller number of cases of strong tremors compared to days when there were no strong tremors, the set of training data was balanced using the ADASYN algorithm. The obtained models had an average recall value of 0.79, and average accuracy equalled 0.912. The trained models showed high efficiency in predicting minority cases of days with strong tremors for up to 48 h and a relatively low percentage of misclassifications.

Environmental performance assessments of different methods of coal preparation for use in small-capacity boilers: experiment and theory

The purpose of this article is to receive environmental assessments of combustion of different types of coal fuel depending on the preparation (unscreened, size-graded, briquetted and heat-treated) in automated boilers and boilers with manual loading. The assessments were made on the basis of data obtained from experimental methods of coal preparation and calculated methods of determining the amount of pollutant and greenhouse gas emissions, as well as the mass of ash and slag waste. The main pollutants from coal combustion are calculated: particulate matter, benz(a)pyrene, nitrogen oxides, sulfur dioxide, carbon monoxide. Of the greenhouse gases carbon dioxide is calculated. As a result of conducted research it is shown that the simplest preliminary preparation (size-graded) of coal significantly improves combustion efficiency and environmental performance: emissions are reduced by 13% for hard coal and up to 20% for brown coal. The introduction of automated boilers with heat-treated coal in small boiler facilities allows to reduce emissions and ash and slag waste by 2–3 times. The best environmental indicators correspond to heat-treated lignite, which is characterized by the absence of sulfur dioxide emissions.

Numerical simulation of hydraulic fracture extension patterns at the interface of coal-measure composite rock mass with Cohesive Zone Model

This study presents the development of a numerical computational model for hydraulic fracturing of coal-measure rock mass. The model is based on the B-K hybrid fracture energy criterion and is implemented using the extended finite element method (XFEM) and cohesive zone model (CZM) in the ABAQUS software. The study took into account the elastic-plastic damage properties of the coal-measure rock mass, as well as the combined effects of tensile and shear damage during the start and expansion of hydraulic fractures. The expansion trajectories and fracture morphology of hydraulic fractures at the interface of coal-measure rock mass under different lithological combinations (lithological strength differences) and ground stress conditions are revealed, and the main controlling factors affecting the expansion across the bedding are clarified. The study provides valuable insights into the management of hydraulic fracturing in the challenging context of hard roof coal mines, the stimulation of coal-measure gas co-production reservoirs, and the development of effective fracturing stimulation strategies for shale oil reservoirs interlayered with thin sandstone, and it can promote the development of industrial production technology for coal-measure gas and shale oil and gas resources, and is beneficial to increase the proportion of clean energy in China's energy consumption structure, and thus promoting a further reduction in the carbon emissions from energy consumption.

68 Degrees: New York City's Residential Heat and Hot Water Code as an Invisible Energy Policy.

For over a century, New York's Residential Heat and Hot Water Code has controlled the distribution of heat in New York City. Established in 1918 by New York's Department of Health, it mandated that all residential and office spaces in the city be heated to sixty-eight degrees Fahrenheit at all times. Changes to it in the ensuing years sought not only to protect New Yorkers' health but reflected pressures in New York's fuel economy, which experienced periods of shortages and a transition from anthracite coal to oil that started between the two World Wars. Consequently, the standardization of sixty-eight degrees Fahrenheit reflected shifting assumptions about health and the "right to heat" for different communities over time, and the practical need to ensure affordable fuel for the city's population. The Heat Code, accordingly, played a crucial role in shaping energy consumption in New York and helping to formulate an "invisible energy policy"-that is, a policy developed in non-energy fields, such as health and housing, that alters energy usage in important but inconspicuous ways, with important consequences for the environment and for social justice.

The influence of combustion of various types of hard coal on the level of pollutant emission

The influence of combustion of various types of hard coal on the level of pollutant emission

Wind Power Plants and Selected Technical and Economic Aspects of Their Construction on Mine Heaps

As a result of energy transformation and decarbonization, the production of hard coal and lignite mining plants is gradually being phased out. Mine heaps, i.e., mine waste heaps, created as a result of the operation of these plants, are not attractive as land for housing, for the construction of production plants, or for agriculture. One of the most advantageous ways of recultivating these areas is using them as a place for the installation of renewable energy sources. In the case of post-mining heaps, it seems natural to use photovoltaics and wind turbines due to the artificial elevation of the terrain. This issue was analysed within the RFCS project SUMAD (Sustainable Use of Mining Waste Heaps). Experts from various countries and scientific disciplines analysed possible scenarios for the mine heaps’ management, with a special attention to geotechnical, environmental and socio-economic challenges. This article discusses one of the variants, namely the possibility of constructing the wind turbines on mining heaps.

Assessment of Energy and Heat Consumption Trends and Forecasting in the Small Consumer Sector in Poland Based on Historical Data

The paper outlines the methodology employed for desk-based research, which involved gathering and analyzing empirical data on energy and heating consumption in the Polish small consumer sector. Secondary sources, including reports, documents, scientific publications, and public statistics, were utilized to ensure a comprehensive understanding of the subject matter. The research methodology ensured the acquisition and examination of reliable and extensive data regarding energy and heat consumption among small consumers in Poland. The study investigated consumption trends of hard coal, electricity, and natural gas in Polish households from 2006 to 2021. The findings revealed an increasing pattern in electricity and natural gas consumption, alongside a simultaneous decline in the usage of hard coal. Future consumption was estimated using trend models, and factors contributing to changes in energy consumption patterns were examined, with forecasts to 2027. To achieve decarbonization and address climate objectives, the study underscores the need to increase the proportion of renewable energy sources and boost energy efficiency. The significance of reducing household energy consumption through enhanced insulation, smart energy management systems, and low-carbon alternatives is emphasized. Additionally, the study addresses Poland’s future energy plans as a proactive step toward decarbonizing the national economy. In summary, the study furnishes valuable insights into energy consumption trends and their determinants in the Polish small consumer sector.

Coal and Gas Outburst Risk Assessment Using Cluster Analysis Method

Mining has historically been known as a high-risk industry. Coal and gas outbursts are one of the most significant accidents that occur in underground coal mines. Despite many years of research, the resources and mechanisms of this phenomenon are not well understood. Thus, it is difficult to forecast and control these events. As the mining depth and density increase, initial gas pressure and gas content of coal seams continue to increase, and the risk of explosion increases. Hence, explosion-prone areas expand gradually. As a result, a dynamic phenomenon has emerged in areas where there is no danger of outbursts. The risk of outbursts becomes more and more serious in coal mines. A coal outburst risk assessment includes evaluating the risk factors to what degree are present and then determining the risk areas of the mine. In this study, the Cluster Analysis method was implemented to identify the risk level of coal seams based on the evaluation of the outburst risk factors for an underground coal mine. Coal and gas outbursts occurring in Zonguldak hard coal basin were divided into two clusters, Cluster A and Cluster B. Coal seams in Cluster A were determined riskier than Cluster B coal seams.