Journal articles on the topic 'Coal Nitrogen content China'
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1
Wang, Xiao Mei, Yang Quan Jiao, Xiao Ming Wang, Li Qun Wu, Lei Qiao, and Hui Li Xie. "The Concentration of Environmentally Important Trace Elements in Permian Coals in Xinan Coalfield, Henan, China." Advanced Materials Research 807-809 (September 2013): 2215–19. http://dx.doi.org/10.4028/www.scientific.net/amr.807-809.2215.
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The concentration of fourteen environmentally important trace elements (Be, V, Cr, Co, Ni, Cu, Zn, Mo, Sn, Ba, Tl, Pb, Th and U) was studied in thirteen coal samples from Xinan coalfield, Henan province. In addition, virtrinite reflectance analysis, proximate analysis and elemental analysis were also conducted on these samples. The vitrinite reflectance values (Ro) ranges from 2% to 2.35%, revealing that these samples are lean coal. The coals have low moisture content, with Madvalue ranging from 0.57 to 0.95%. The ash and volatile matter content vary between 8.11-22.61% and 10.36-14.64%, respectively. Carbon, hydrogen, sulphur and nitrogen content vary between 71.51-83.54%, 3.068-3.879%, 0.494-2.326% and 0.953-1.38%, respectively. In comparison with the crustal average (Clarke value), some potentially hazardous elements are moderately enriched in the coals from Xinan coalfield, such as Pb, Th, U, Sn and Mo. The average concentration of most of the elements in Xinan coalfield coals is in the range of Chinese coals and world coals. No elements with the abnormally high concentrations analyzed are found.
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Xu, Yanfei, Shikai An, Yongchun Chen, Chao Yuan, and Pengfei Tao. "Effect of Biomass Improvement Method on Reclaimed Soil of Mining Wasteland." Advances in Civil Engineering 2022 (May 2, 2022): 1–10. http://dx.doi.org/10.1155/2022/8375918.
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Aiming at the problem of soil improvement for mining wasteland reclamation, this article takes the coal mining subsidence reclamation area of a coal mine in the east of China as the research object. Compost improvement and green manure improvement experiments were carried out to study the impact of different biomass improvement methods on the quality of reclaimed soil. 10 soil physical and chemical indicators including water content, total nitrogen, ammonia nitrogen, nitrate nitrogen, available phosphorus, available potassium, total phosphorus, organic matter, pH, and conductivity were selected to evaluate the effect of soil improvement. After 5 months of soil improvement, the results showed that planting alfalfa and Mexican corn in the reclaimed area can increase soil available phosphorus, available potassium, total phosphorus, and organic matter content. Cattail, a common aquatic plant in the coal mining subsidence area in the east, is used to make organic compost. When the compost is applied to reclaimed soil, the content of available phosphorus, available potassium, and total phosphorus in the soil can be significantly increased. Using white vanilla clover as green manure for reclaiming soil can significantly increase the content of nitrate nitrogen, available phosphorus, available potassium, and total phosphorus in the soil. Biomass improvement technology can improve the fertility level of coal mine reclamation soil in a short time. It is conducive to promoting the restoration of soil fertility of mining wasteland and realizing the sustainable development and utilization of plant resources and land resources.
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Xu, Hongjie, Shuxun Sang, Jingfen Yang, Jun Jin, Huihu Liu, Xiaozhi Zhou, and Wei Gao. "Evaluation of coal and shale reservoir in Permian coal-bearing strata for development potential: A case study from well LC-1# in the northern Guizhou, China." Energy Exploration & Exploitation 37, no. 1 (October 28, 2018): 194–218. http://dx.doi.org/10.1177/0144598718807553.
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Indentifying reservoir characteristics of coals and their associated shales is very important in understanding the co-exploration and co-production potential of unconventional gases in Guizhou, China. Accordingly, comprehensive experimental results of 12 core samples from well LC-1# in the northern Guizhou were used and analyzed in this paper to better understand their vertical reservoir study. Coal and coal measured shale, in Longtan Formation, are rich in organic matter, with postmature stage of approximately 3.5% and shales of type III kerogen with dry gas generation. All-scale pore size analysis indicates that the pore size distribution of coal and shale pores is mainly less than 20 nm and 100 nm, respectively. Pore volume and area of coal samples influenced total gas content as well as desorbed gas and lost gas content. Obvious relationships were observed between residual gas and BET specific surface area and BJH total pore volume (determined by nitrogen adsorption). For shale, it is especially clear that the desorbed gas content is negatively correlated with BET specific surface area, BJH total pore volume and clay minerals. However, the relationships between desorbed gas and TOC (total organic carbon) as well as siderite are all well positive. The coals and shales were shown to have similar anoxic conditions with terrestrial organic input, which is beneficial to development of potential source rocks for gas. However, it may be better to use a low gas potential assessment for shales in coal-bearing formation because of their low S1+S2 values and high thermal evolution. Nevertheless, the coalbed methane content is at least 10 times greater than the shale gas content with low desorbed gases, indicating that the main development unconventional natural gas should be coalbed methane, or mainly coalbed methane with supplemented shale gas.
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Ruan, Mengying, Yuxiu Zhang, and Tuanyao Chai. "Rhizosphere Soil Microbial Properties on Tetraena mongolica in the Arid and Semi-Arid Regions, China." International Journal of Environmental Research and Public Health 17, no. 14 (July 16, 2020): 5142. http://dx.doi.org/10.3390/ijerph17145142.
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Tetraena mongolica is a rare and endangered species unique to China. The total number and density of Tetraena mongolica shrubs in desertification areas have experienced a sharp decrease with increases in coal mining activities. However, available information on the T. mongolica rhizosphere soil quality and microbial properties is scarce. Here, we investigated the effect of coal mining on the soil bacterial community and its response to the soil environment in the T. mongolica region. The results showed that the closer to the coal mining area, the lower the vegetation coverage and species diversity. The electrical conductivity (EC) in the contaminated area increased, while the total nitrogen (TN), available phosphorus (AP), available potassium (AK), and soil organic carbon (SOC) decreased. The activity of NAG, sucrose, β-glucosidase, and alkaline phosphatase further decreased. In addition, the mining area could alter the soil’s bacterial abundance and diversity. The organic pollutant degradation bacteria such as Sphingomonas, Gemmatimonas, Nocardioides, and Gaiella were enriched in the soil, and the carbon-nitrogen cycle was changed. Canonical correspondence analysis (CCA) and Pearson’s correlation coefficients showed that the change in the bacterial community structure was mainly caused by environmental factors such as water content (SWC) and EC. Taken together, these results suggested that open pit mining led to the salinization of the soil, reduction the soil nutrient content and enzyme activity, shifting the rhizosphere soil microbial community structure, and altering the carbon-nitrogen cycle, and the soil quality declined and the growth of T. mongolica was affected in the end. Therefore, the development of green coal mining technology is of great significance to protect the growth of T. mongolica.
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Yang, Dejun, Yajun Zhang, and Xiuqin Chen. "EFFECT OF COAL MINING ON SOIL NITROGEN DISTRIBUTION IN SEMI-ARID MINING AREA OF WESTERN CHINA." Journal of Environmental Engineering and Landscape Management 27, no. 3 (September 3, 2019): 163–73. http://dx.doi.org/10.3846/jeelm.2019.10795.
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Soil nitrogen is a key indicator of soil quality and plays a significant role for plant growth. Therefore, it is very important to study soil nitrogen distribution, especially in semi-arid area of western China. Fewer scholars paid attention to the effect on soil nitrogen due to coal mining in semi-arid mining areas of western China. In this paper, soil samples of different locations were tested in both the loess region and the aeolian sand region in the Daliuta mining area in Shaanxi Province. The impacts of mining subsidence on soil nitrogen were investigated. The soil nitrogen distributions between the loess region and the aeolian sand region were compared, and used the principal component analysis method to evaluate soil quality in semi-arid mining area. The results showed that the comprehensive score of soil quality in the loess region was as follows: the internal pulling stress zone (NLS) > the external pulling stress zone (WLS) > the compressive stress zone (YS) > the neutral zone (ZX). The content of soil total nitrogen in YS-zone was the lowest in the loess region. The loss of nitrogen increased with time in the mining area, in which the total nitrogen loss at the depth of 0−15 cm was 0.27 g/kg, and the alkaline nitrogen loss at the depth of 0−15 cm was 1.08 mg/kg. In the aeolian sand region, the comprehensive score of soil quality was as follows: WLS > FC (the non-mining zone) > ZX > NLS > YS. The amount of soil nitrogen content in the loess region was larger than that in the aeolian sand region. It was found that for the loess region, the relationship between total nitrogen and nitrate nitrogen showed a significant positive correlation. It was also a significant positive correlation between ammonium nitrogen and alkaline nitrogen. In the aeolian sand region, there was a significant positive correlation between total nitrogen and alkaline nitrogen. There was no significant correlation among other nitrogen forms.
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Lin, Haifei, Yang Bai, Jingting Bu, Shugang Li, Min Yan, Pengxiang Zhao, and Lei Qin. "Comprehensive Fractal Model and Pore Structural Features of Medium- and Low-Rank Coal from the Zhunnan Coalfield of Xinjiang, China." Energies 13, no. 1 (December 18, 2019): 7. http://dx.doi.org/10.3390/en13010007.
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Medium and low-rank coal from the Zhunnan coalfield of Xinjiang in China was investigated for quantitatively characterizing its range of aperture structure. The pore parameters were determined by nitrogen adsorption at low temperature and mercury injection at high pressure, and the full aperture was determined. The FHH model, Menger model, Sierpinski model, and a thermodynamic model were used to calculate the comprehensive fractal dimension of the coal samples over the full range of aperture. The fractal characteristics of the pores of medium- and low-rank coal were quantitatively analyzed, which provided a reference for the overall characterization of pore structure heterogeneity in this coalfield. The results show that the FHH model and thermodynamic model more accurately calculate the fractal dimensions of less and greater than the joint pore position, respectively. The comprehensive fractal dimension of the low-rank coal pore is 2.8005–2.8811 and that of medium rank coal is 2.5710–2.6147. When compared with the medium-rank coal, pores of the low-rank coal are more developed and they exhibit a more complex structure with stronger heterogeneity. The comprehensive fractal dimension of the pores is a negative correlation with average pore size, vitrinite content, and maximum vitrinite reflectance, and positive correlation with pore volume, pore specific surface area, inertinite content, and exinite content.
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Ma, Kang, Yuxiu Zhang, Mengying Ruan, Jing Guo, and Tuanyao Chai. "Land Subsidence in a Coal Mining Area Reduced Soil Fertility and Led to Soil Degradation in Arid and Semi-Arid Regions." International Journal of Environmental Research and Public Health 16, no. 20 (October 16, 2019): 3929. http://dx.doi.org/10.3390/ijerph16203929.
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Underground coal mining in western China causes heavy land subsidence and alters the soil ecology. However, the effects of land subsidence on soil fertility are not currently known, and the key factors governing its impact remain unclear in sandy land. We investigated the effects of land subsidence induced by underground mining on the soil quality in western China. Soil samples were collected at 0–15 cm and 15–30 cm from control and subsidence areas in three coal mines. The results showed that the soil water content (SWC), clay and silt percentage, total nitrogen (TN), dissolved organic carbon (DOC), ammonia nitrogen (NH4+-N), nitrate nitrogen (NO3--N), available phosphorus (AP), and available potassium (AK) of the subsidence areas were significantly lower than those of the control areas. The saccharase, urease, and alkaline phosphatase activities in the subsidence areas decreased compared to those in the control areas, while the sand percentage of soil tended to increase. Soil nutrient contents, bacterial quantities, and activities of soil enzymes were positively correlated with SWC. Redundancy analysis (RDA) showed that the soil particle size distribution, SWC, and electrical conductivity (EC) were the major environmental factors driving changes in soil properties. These results indicated that land subsidence induced by coal mining caused losses in surface soil water and nutrients, and ultimately led to soil quality degradation. Therefore, the reclamation of mining subsidence land might be necessary, especially in arid and semi-arid areas.
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Sakai, Yuji, Masataka Nakamura, and Chang Wang. "Soil Carbon Sequestration Due to Salt-Affected Soil Amelioration with Coal Bio-Briquette Ash: A Case Study in Northeast China." Minerals 10, no. 11 (November 16, 2020): 1019. http://dx.doi.org/10.3390/min10111019.
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Increasing soil carbon storage and biomass utilization is an effective process for mitigating global warming. Coal bio-briquettes (CBB) are made using two low-ranked coals with high sulfur content, corn stalks, and calcium hydroxide, and the combustion ash can ameliorate the physicochemical properties in salt-affected soil. CBB ash contains mainly calcium compounds, such as calcium sulfate, calcium hydroxide, and calcium carbonate, and coal fly ash and biomass ash. In this paper, changes in soil carbon and nitrogen content through salt-affected soil amelioration during 5 months using two CBB ashes and pig manure were examined in Northeast China. Application rates of CBB ash were 0 tha−1 (control), 11.6 tha−1, 23.2 tha−1, 46.4 tha−1, and 69.6 tha−1. Consequently, total carbon content in topsoil (0–0.15 m) after harvest of maize in all test fields indicated a range between 27.7 tCha−1 and 50.2 tCha−1, and showed increased levels compared to untreated salt-affected soil. In a 3.0% (69.6 tha−1) application plot of only CBB ash with higher carbon and higher exchangeable Ca2+, the carbon content increased by 51.5% compared to control plot, and changes in carbon sequestration compared to untreated soil was roughly twice that of the control plot. CBB ash contributed to carbon application and pig manure supply as a form of N fertilization in the case of all test plots. Changes in carbon content due to soil amelioration have a significant relationship with changes in corn production and soil chemical properties, such as pH, Na+, Cl−, sodium adsorption ratio (SAR), and exchangeable sodium percentage (ESP). Therefore, CBB production from low-ranked coal and waste biomass, and the use of CBB ash in agriculture is advocated as an effective means for sequestering carbon.
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Ding, Lili, and Qiang Zeng. "Study on Characteristics of Coal Spontaneous Combustion in Kerjian Mining Area, Xinjiang, China." Minerals 12, no. 12 (November 25, 2022): 1508. http://dx.doi.org/10.3390/min12121508.
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The spontaneous combustion of coal is a disaster associated with coal mining. In this study, the authors investigated the characteristics of spontaneous combustion of coal at different temperatures (room temperature, 50–500 °C with 50 °C interval) using Fourier transform infrared spectroscopy (FTIR), high-resolution transmission electron microscopy (HRTEM), etc. The results showed the aromatic structure was mainly naphthalene. The aliphatic hydrocarbons were long chain. Oxygen, nitrogen, and sulphur existed as C-O, pyridine, pyrrole nitrogen, aliphatic sulphur, and sulfone. The molecular structural formula is C142H112N2O22. The stable 3D structural was obtained through optimization. Thermogravimetric analysis results showed the critical and dry-cracking temperatures of coal samples showed downward trends overall, whereas the acceleration and thermal-decomposition temperatures varied greatly with increase in oxidation temperature. The activation energy change pattern of 4 stages is not obvious. The FTIR results showed the contents of self-associated OH changed greatly. The aliphatic hydrocarbons changed greatly at 30–150 °C and 300–500 °C. The C-O showed increasing trends, whereas the C=O decreased consistently. The HRTEM results showed the aromatic fringes in coal samples were dominated by 1 × 1 and 2 × 2, the contents of which accounted for more than 80% of the total fringes.
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Yang, Xin, Gongda Wang, Mingqi Ni, Longyong Shu, Haoran Gong, and Zhie Wang. "Investigation on Key Parameters of N2 Injection to Enhance Coal Seam Gas Drainage (N2-ECGD)." Energies 15, no. 14 (July 11, 2022): 5064. http://dx.doi.org/10.3390/en15145064.
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Practice shows that CO2/N2-ECBM is an effective technology to enhance coalbed methane. However, there are few field tests in which the technology is applied to enhance the gas drainage in underground coal mines, and the effect is uncertain. In this study, firstly, the reasons for the decrease of gas drainage efficiency in the exhaustion period were analyzed based on the theory of fluid mechanics. Secondly, the mechanism of N2 injection to enhance coal seam gas drainage (N2-ECGD) was discussed: with the gradual decrease of gas pressure in the drainage process, coal seam gas enters a low-pressure state, the driving force of flow is insufficient, and the drainage enters the exhaustion period. The nitrogen injection technology has triple effects of “promoting flow”, “increasing permeability” and “replacing”. Thirdly, the numerical simulations of the nitrogen pressure on drainage effect were carried out based on the fully coupled model. The results show that the higher the nitrogen pressure, the greater the displacement effect between injection and drainage boreholes, the larger the effective range. Finally, a field test of N2-ECGD was carried out in the Liu Zhuang coal mine in Huainan Coalfield, China. The results show that N2 injection can significantly enhance the gas flow rate and CH4 flow rate in the drainage boreholes, and the coal seam gas content decreased 39.73% during N2 injection, which is about 2.6–3.3 times that of the conventional drainage. The research results provide an important guidance for promoting the application of N2-ECGD in underground coal mines.
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Yi, Qitao, Xiaomeng Wang, Tingting Wang, Xijie Qu, and Kai Xie. "Eutrophication and nutrient limitation in the aquatic zones around Huainan coal mine subsidence areas, Anhui, China." Water Science and Technology 70, no. 5 (July 4, 2014): 878–87. http://dx.doi.org/10.2166/wst.2014.293.
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The eutrophication of three small lakes in the aquatic zones at the Huainan coal mine subsidence areas, designated as east site (ES), central site (CS), and west site (WS), were studied. Nutrient content, species, and nitrogen (N) to phosphorus (P) ratios were obtained through water quality analyses. Nutrient limitation was evaluated by nutrient enrichment bioassays (NEBs) in the autumn of 2012 and spring of 2013. Average annual concentrations of total phosphorus (TP) were 0.05, 0.08, and 0.10 mg/L, and total nitrogen (TN) concentrations were 0.77, 1.95, and 2.06 mg/L in the water column at CS, ES, and WS, respectively. All of the three lakes exhibited ‘meso-eutrophic’ states and the TN:TP ratio ranged from 25:1 to 74:1 with variability between seasons and sites. NEBs verified that primary productivity in the lakes at ES and WS were mainly limited by P, while N limitation or N and P co-limitation was present in the aquatic zones at CS due to unavailable dissolved inorganic nitrogen. In the studied lakes, the blue-green algae, which comprised 70% of all identified species, was the predominant taxa, while the micro-zooplankton taxa was dominant, indicating a typical trophic structure of eutrophic lakes.
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Park, Minhan, Yujue Wang, Jihyo Chong, Haebum Lee, Jiho Jang, Hangyul Song, Nohhyeon Kwak, et al. "Simultaneous Measurements of Chemical Compositions of Fine Particles during Winter Haze Period in Urban Sites in China and Korea." Atmosphere 11, no. 3 (March 16, 2020): 292. http://dx.doi.org/10.3390/atmos11030292.
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We performed simultaneous measurements of chemical compositions of fine particles in Beijing, China and Gwangju, Korea to better understand their sources during winter haze period. We identified PM2.5 events in Beijing, possibly caused by a combination of multiple primary combustion sources (biomass burning, coal burning, and vehicle emissions) and secondary aerosol formation under stagnant conditions and/or dust sources under high wind speeds. During the PM2.5 events in Gwangju, the contribution of biomass burning and secondary formation of nitrate and organics to the fine particles content significantly increased under stagnant conditions. We commonly observed the increases of nitrogen-containing organic compounds and biomass burning inorganic (K+) and organic (levoglucosan) markers, suggesting the importance of biomass burning sources during the winter haze events (except dust event cases) at both sites. Pb isotope ratios indicated that the fraction of Pb originated from possibly industry and coal combustion sources increased during the PM2.5 events in Gwangju, relative to nonevent days.
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Xu, Zhi, Ming Li, Yu Xu, and Luwei Sun. "Fractal Characteristics and Its Controlling Factors of Nanopore of Coal from Shanxi Province, North China." Journal of Nanoscience and Nanotechnology 21, no. 1 (January 1, 2021): 727–40. http://dx.doi.org/10.1166/jnn.2021.18515.
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Much attention has been recently paid to the Carboniferous-Permian coal-bearing strata in Shanxi Province, now the largest producing coalbed methane field in China. In this study, a comprehensive approach of mercury injection, low-temperature liquid nitrogen adsorption, and permeability experiments was adopted to investigate the structure and fractal characteristics of nanopores in the Carboniferous-Permian coal (with 0.77%˜3.04% Ro,ran). Based on the fractal model, two fractal dimensions D1 and D2 corresponding to diffusion pore (<65 nm) and seepage pore (pore size ≥65 nm), respectively, were calculated, and the relationships between the fractal dimensions with the pore structure parameters and permeability are discussed here. The results indicate that the studied coal samples have good fractal characteristics and that the calculated linear correlation coefficients are higher than 0.80. The fractal dimension D1 of the diffusion pores ranges from 2.3777 to 2.4624, with an average of 2.4173, while the fractal dimension D2 of the seepage pores is between 2.5844 and 2.6256, with an average of 2.5990. The fractal dimensions D1 of the diffusion pores increases with an increase in the BET specific surface area, vitrinite content, and Ro,ran while it decreases with an increase in the permeability, and has a weak correlation with the total pore volume. The correlation coefficients R2 for the fractal dimension D2 of the seepage pores, pore parameters, permeability, and maceral composition ranges from 0.0357 to 0.2551. These results indicate that uncertain relationships exist among these parameters.
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Chen, Hao, Wenguang Tian, Zhenhong Chen, Qingfeng Zhang, and Shu Tao. "Genesis of Coalbed Methane and Its Storage and Seepage Space in Baode Block, Eastern Ordos Basin." Energies 15, no. 1 (December 23, 2021): 81. http://dx.doi.org/10.3390/en15010081.
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The Baode block on the eastern margin of the Ordos Basin is a key area for the development of low-rank coalbed methane (CBM) in China. In order to find out the genesis of CBM and its storage and seepage space in Baode block, the isotopic testing of gas samples was carried out to reveal the origin of CH4 and CO2, as well, mercury intrusion porosimetry, low temperature nitrogen adsorption, and X-ray CT tests were performed to characterize the pores and fractures in No. 4 + 5 and No. 8 + 9 coal seams. The results showed that the average volume fraction of CH4, N2, and CO2 is 88.31%, 4.73%, and 6.36%, respectively. No. 4 + 5 and No. 8 + 9 coal seams both have biogenic gas and thermogenic methane. Meanwhile, No. 4 + 5 and No. 8 + 9 coal seams both contain CO2 generated by coal pyrolysis, which belongs to organic genetic gas, while shallow CO2 is greatly affected by the action of microorganisms and belongs to biogenic gas. The average proportion of micropores, transition pores, mesopores, and macropores is 56.61%, 28.22%, 5.10%, and 10.07%, respectively. Samples collected from No. 4 + 5 coal seams have developed more sorption pores. Meanwhile, samples collected from No. 8 + 9 coal seams exhibited a relatively low degree of hysteresis (Hg retention), suggesting good pore connectivity and relatively high seepage ability, which is conducive to gas migration. The connected porosity of coal samples varies greatly, mainly depending on the relative mineral content and the proportion of connected pores.
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Zheng, Qiming, Qinfu Liu, Bo Huang, and Weilong Zhao. "Isotopic composition and content of organic nitrogen in the coals of Qinshui Coalfield, North China." Journal of Geochemical Exploration 149 (February 2015): 120–26. http://dx.doi.org/10.1016/j.gexplo.2014.12.002.
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Zhu, Hongfen, Ruipeng Sun, Zhanjun Xu, Chunjuan Lv, and Rutian Bi. "Prediction of Soil Nutrients Based on Topographic Factors and Remote Sensing Index in a Coal Mining Area, China." Sustainability 12, no. 4 (February 21, 2020): 1626. http://dx.doi.org/10.3390/su12041626.
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(1) Background: Coal mining operations caused severe land subsidence and altered the distributions of soil nutrients that influenced by multiple environmental factors at different scales. However, the prediction performances for soil nutrients based on their scale-specific relationships with influencing factors remains undefined in the coal mining area. The objective of this study was to establish prediction models of soil nutrients based on their scale-specific relationships with influencing factors in a coal mining area. (2) Methods: Soil samples were collected based on a 1 × 1 km regular grid, and contents of soil organic matter, soil available nitrogen, soil available phosphorus, and soil available potassium were measured. The scale components of soil nutrients and the influencing factors collected from remote sensing and topographic factors were decomposed by two-dimensional empirical mode decomposition (2D-EMD), and the predictions for soil nutrients were established using the methods of multiple linear stepwise regression or partial least squares regression based on original samples (MLSROri or PLSROri), partial least squares regression based on bi-dimensional intrinsic mode function (PLSRBIMF), and the combined method of 2D-EMD, PLSR, and MLSR (2D-EMDPM). (3) Results: The correlation types and correlation coefficients between soil nutrients and influencing factors were scale-dependent. The variances of soil nutrients at smaller scale were stochastic and non-significantly correlated with influencing factors, while their variances at the larger scales were stable. The prediction performances in the coal mining area were better than those in the non-coal mining area, and 2D-EMDPM had the most stable performance. (4) Conclusions: The scale-dependent predictions can be used for soil nutrients in the coal mining areas.
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Huang, Hai, Jing Guo, and Yuxiu Zhang. "The Response of Arbuscular Mycorrhizal Fungal Communities to the Soil Environment of Underground Mining Subsidence Area in Northwest China." International Journal of Environmental Research and Public Health 17, no. 24 (December 8, 2020): 9157. http://dx.doi.org/10.3390/ijerph17249157.
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Fully mechanized mining technology applied over a very large working face is typically utilized for coal exploitation in Northwest China and triggered two types of land subsidence above the goaf edge and center. However, the effects of mining subsidence on arbuscular mycorrhizal fungal (AMF) communities are still unknown. Here, we investigated the soil physicochemical properties and the response of AMF communities to the soil environment at the margin and center of the subsidence area of the same working face. Our results showed the soil water content, nutrient content and enzyme activity were significantly decreased with land desertification at the margin of the subsidence area but were less affected at the subsidence center. Utilizing high-throughput sequence analysis, six Glomeromycotan genera were detected. The relative abundance of Glomus and Ambispora at the margin of the subsidence area decreased, while Paraglomus and Diversispora increased. The total OTU richness was significantly correlated with moisture. Redundancy analysis showed the main environmental factors driving the changes in AMF community structure were available nitrogen, available potassium and available phosphorus. All these results indicated land cracks need to be repaired in time at subsidence edge to prevent the decline of soil fertility.
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Zhang, Jiali, Yinghong Liu, Meilan Wen, Chaojie Zheng, Sheli Chai, Liangliang Huang, and Panfeng Liu. "Distribution Characteristics and Ecological Risk Assessment of Nitrogen, Phosphorus, and Some Heavy Metals in the Sediments of Yueliang Lake in Western Jilin Province, Northeast China." Water 14, no. 20 (October 19, 2022): 3306. http://dx.doi.org/10.3390/w14203306.
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This study seeks to clarify the content characteristics, spatial distribution, potential sources and ecological risks of nitrogen, phosphorus and some heavy metals (As, Hg, Cd, Cr, Cu, Pb, Zn and Ni) in the sediments of Yueliang Lake. Nitrogen, phosphorus and heavy metals were analyzed in the surface and core sediments of Yueliang Lake. The present situation of heavy metal pollution and the degree of potential ecological risk in sediments was evaluated by the geo-accumulation index (Igeo) and potential ecological risk index (RI). The correlation (CA) and principal component analysis (PCA) methods were used to analyze the potential sources of the main pollutants among the heavy metals. The results show that the total nitrogen (TN = 2305 mg/kg) and total phosphorus (TP = 530 mg/kg) in the surface sediments of Yueliang Lake are at medium and low levels, respectively. The average content of organic matter was 2.17%, and the nutrient ratio was 6.90–11.92, which was significantly higher in the northwest than in the middle and east of Yueliang Lake, indicating that the organic matter was a mixture of endogenous aquatic plants and exogenous terrestrial plants in the sediments. From two evaluation indices (RI and Igeo) calculated using element contents, the heavy metals in the surface sediments were at a moderate ecological risk level. The level of Hg was moderately polluted, Pb and Cd were at the mildly polluted level, and Cu, Zn, As, Cr and Ni were at pollution-free levels. Except for Hg, the other elements in the core sediment are basically not polluting, and the whole is at the level of slight ecological risk. The sources of heavy metals in the sediments are roughly divided into three categories. The first category is natural sources, including Cr, Ni, As, Zn and Cu. The second category includes Cd and Hg and the main sources are highly related to energy development and agricultural activities. The third category is light Pb pollution caused by vehicular traffic and coal-related industrial activities. Therefore, the pollution problems caused by tourism development and agricultural activities should be considered in the future development of the Yueliang Lake area.
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Gao, Hai-Tao, Yan-Ming Zhu, Fu-Hua Shang, and Chong-Yu Chen. "Study on the Shale Gas Reservoir-Forming Characteristics of the Taiyuan Formation in the Eastern Qinshui Basin, China." Journal of Nanoscience and Nanotechnology 21, no. 1 (January 1, 2021): 72–84. http://dx.doi.org/10.1166/jnn.2021.18465.
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Shales are widely developed in the strata of the Carboniferous-Permian coal measures in the Qinshui Basin, and these shales have great potential for shale gas exploration. In this paper, the shales of the Taiyuan Formation in the eastern Qinshui Basin are studied. The shales of the Taiyuan Formation in the study area are investigated through field investigation, organic geochemical testing, X-ray diffraction, scanning electron microscopy, high pressure mercury injection, low temperature liquid nitrogen adsorption and PetroMod simulation and through other tests to study the reservoir characteristics, such as organic geochemistry, mineralogy, petrology, pore permeability, and gas burial history. The results show that the shales of the Taiyuan Formation are well developed over the whole area with a thickness of more than 60 m. The average organic matter content is 2.95%, and the kerogen type is type III. The shale maturity (average value is 2.45%) corresponds to the stage of high maturity evolution, indicating that a large amount of shale gas has been generated in this area. A high content of quartz and clay minerals indicates a high fracturability. The nanopores in the shale reservoir are well developed at pore sizes between 2˜10 nm and greater than 1000 nm; however, the pores at the other pore sizes are poorly developed, resulting in weak pore connectivity in the reservoir. According to the results of the PetroMod simulation, the shale of the Taiyuan Formation has undergone two subsidence and two uplift processes. The Yanshanian magmatic intrusion is the key factor for the rapid increase in gas production. In addition, the geological structure of the area is relatively simple, and the burial history and caprock thickness are also the main controlling factors of gas generation and preservation. The shale-sandstone-shale combination and shale-coal-shale combination are the main models of shale gas preservation. This comprehensive study suggests that the shale gas of the Taiyuan Formation in the eastern Qinshui Bain has good potential for exploration and development.
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Gao, Yakun, Yinli Bi, Shaopeng Ma, Yanxu Zhang, Yun Guo, Yang Zhou, Shihao Xu, and Peter Christie. "Yields of Buckwheat and Alfalfa in an Intercropping System Inoculated with Dark Septate Endophytes in a Coal Mining Subsidence Dryland Area." Agronomy 12, no. 11 (November 16, 2022): 2860. http://dx.doi.org/10.3390/agronomy12112860.
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Coal mining subsidence areas in north Shaanxi province in north China are commonly low-fertility drylands, and intercropping is a popular method locally of maximizing crop yields. Inoculation with dark septate endophytes (DSE) can increase the yields of conventional crops grown in monoculture, but the effects of DSE on the growth and yield of intercropped plants are unknown. Here, a field experiment was conducted in a coal mining subsidence area on the loess plateau in 2020 and 2021. The two crops were buckwheat and alfalfa, with four treatments for each crop: sole cropping control, sole cropping with DSE inoculation, intercropping control, and intercropping with DSE inoculation. The yields, land equivalent ratios, DSE colonization rates, and yield components of buckwheat and alfalfa were compared in the different treatments. Stepwise regression and path analysis was conducted to identify the factors that determined crop yields. Yields of intercropped buckwheat and alfalfa with DSE inoculation increased in two consecutive years compared with sole cropping control, with yields increasing in 2020 by 117 and 86%, respectively. In 2021, the yield of buckwheat in intercropping with DSE inoculation did not increase significantly, but the yield of alfalfa increased by 120% compared with the sole cropping control. Buckwheat-alfalfa intercropping has the advantage of increasing the yield. DSE inoculation significantly increased the yield of buckwheat-alfalfa intercropping in 2020, but there was no yield advantage in 2021. The yield components of buckwheat and alfalfa showed inconsistent differences among experimental treatments. Stepwise regression and path analysis shows that the DSE colonization rate played an important role in the yield, which was an increased in buckwheat and alfalfa in 2020 and 2021. DSE affected the buckwheat yield indirectly by increasing the grain weight per plant, plant phosphorus uptake, and plant nitrogen content. DSE indirectly affected alfalfa yields by increasing plant nitrogen uptake and plant height. DSE may therefore have some potential to increase yields in buckwheat-alfalfa intercropping systems in coal mining subsidence areas.
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Guo, Yangnan, Junlong Wu, and Yan Yu. "Differential Response of Soil Microbial Community Structure in Coal Mining Areas during Different Ecological Restoration Processes." Processes 10, no. 10 (October 5, 2022): 2013. http://dx.doi.org/10.3390/pr10102013.
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Micro-organisms play important roles in promoting soil ecosystem restoration, but much of the current research has been limited to changes in microbial community structure in general, and little is known regarding the more sensitive and indicative microbial structures or the responses of microbial diversity to environmental change. In this study, based on high-throughput sequencing and molecular ecological network analyses, the structural characteristics of bacterial communities were investigated in response to four different ecological restoration modes in a coal mining subsidence area located in northwest China. The results showed that among soil nutrients, nitrate-nitrogen and fast-acting potassium were the most strongly associated with microbial community structure under different ecological restoration types. Proteobacteria, Actinobacteria, and Acidobacteria were identified as important phyla regarding network connectivity and structural composition. The central natural recovery zone was found to have the smallest network size and low complexity, but high modularity and good microbial community stability. Contrastingly, a highly complex molecular ecological network of soils in the photovoltaic economic zone existed beneath the photovoltaic modules, although no key species, strong bacterial competition, poor resistance to disturbance, and a significant increase in the relative abundance of Gemmatimonadetes were found. Furthermore, the reclamation zone had the highest soil nutrient content, the most complex network structure, and the most key and indicator species; however, the ecological network was less stable and readily disturbed.
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Li, Haiyan, Jing Cheng, Qiang Zhang, Bo Zheng, Yuxuan Zhang, Guangjie Zheng, and Kebin He. "Rapid transition in winter aerosol composition in Beijing from 2014 to 2017: response to clean air actions." Atmospheric Chemistry and Physics 19, no. 17 (September 12, 2019): 11485–99. http://dx.doi.org/10.5194/acp-19-11485-2019.
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Abstract. The clean air actions implemented by the Chinese government in 2013 have led to significantly improved air quality in Beijing. In this work, we combined the in situ measurements of the chemical components of submicron particles (PM1) in Beijing during the winters of 2014 and 2017 and a regional chemical transport model to investigate the impact of clean air actions on aerosol chemistry and quantify the relative contributions of anthropogenic emissions, meteorological conditions, and regional transport to the changes in aerosol chemical composition from 2014 to 2017. We found that the average PM1 concentration in winter in Beijing decreased by 49.5 % from 2014 to 2017 (from 66.2 to 33.4 µg m−3). Sulfate exhibited a much larger decline than nitrate and ammonium, which led to a rapid transition from sulfate-driven to nitrate-driven aerosol pollution during the wintertime. Organic aerosol (OA), especially coal combustion OA, and black carbon also showed large decreasing rates, indicating the effective emission control of coal combustion and biomass burning. The decreased sulfate contribution and increased nitrate fraction were highly consistent with the much faster emission reductions in sulfur dioxide (SO2) due to phasing out coal in Beijing compared to reduction in nitrogen oxides emissions estimated by bottom-up inventory. The chemical transport model simulations with these emission estimates reproduced the relative changes in aerosol composition and suggested that the reduced emissions in Beijing and its surrounding regions played a dominant role. The variations in meteorological conditions and regional transport contributed much less to the changes in aerosol concentration and its chemical composition during 2014–2017 compared to the decreasing emissions. Finally, we speculated that changes in precursor emissions possibly altered the aerosol formation mechanisms based on ambient observations. The observed explosive growth of sulfate at a relative humidity (RH) greater than 50 % in 2014 was delayed to a higher RH of 70 % in 2017, which was likely caused by the suppressed sulfate formation through heterogeneous reactions due to the decrease in SO2 emissions. Thermodynamic simulations showed that the decreased sulfate and nitrate concentrations have lowered the aerosol water content, particle acidity, and ammonium particle fraction. The results in this study demonstrate the response of aerosol chemistry to the stringent clean air actions and identify that the anthropogenic emission reductions are a major driver, which could help to further guide air pollution control strategies in China.
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Beshley, S., V. Baranov, and Y. Shpak. "Effect of coal fly ash and potassium humate on nitrogen and carbon contents in coal industry dump substrate and organs of Sorghum drummondii (Nees ex Steud.) Millsp. & Chase." Visnyk of Lviv University. Biological series, no. 85 (February 25, 2021): 45–52. http://dx.doi.org/10.30970/vlubs.2021.85.05.
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Researched ammonium, nitrite and nitrate nitrogen and organic carbon contents in gray-black unburned rock substrate from coal industry waste rock dump of Central Enrichment Factory (CEF) owned by PJSC “Lviv Coal Company” (Lviv Oblast, Ukraine) and total nitrogen and organic carbon contents in organs of Sorghum drummondii (Nees ex Steud.) Millsp. & Chase under effect of coal fly ash from the Dobrotvir thermal power plant (Lviv Oblast, Ukraine) and potassium humate “ГКВ-45” (made by LLC “PARK”, Lviv Oblast, Ukraine). Found high content of organic carbon and ammonium nitrogen in waste rock dump substrate with contrast to low content of nitrite and nitrate nitrogen compare to relatively optimal soil mixture of the standard. Detected low carbon and nitrogen contents in organs of S. drummondii which grew on the waste rock dump substrate, as well as a significantly increased carbon/nitrogen-ratio (in this research the ratio of organic carbon content to total nitrogen content) compare to plants of the standard. Addition of coal fly ash in waste rock dump substrate decreased ammonium nitrogen and organic carbon contents with contrast to nitrite and nitrate nitrogen increasing, as well as organic carbon and total nitrogen in roots, stalks and leaves of researched plants. Introduction of potassium humate increased nitrite and nitrate nitrogen contents in waste rock dump substrate, organic carbon and total nitrogen contents in organs of S. drummondii. Changing of both studied macronutrients contents in plants under the effect of ameliorants caused decreasing carbon/nitrogen-ratio to the direction of the standard values. Growing of S. drummondii grass for 95 days increased organic carbon content in all options of substrates except the rock with potassium humate addition and decreased ammonium, nitrite and nitrate nitrogen contents in all researched options of substrates without exceptions. Noted that combined effect of coal fly ash and potassium humate on carbon and nitrogen contents in waste rock dump substrate and organs of S. drummondii is stronger than just one of both above mentioned researched ameliorants.
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Lian, Jin Jiang, De Tian Yan, Biao Gao, and Hai Yang Cao. "Coal Bed Methane Reservoir in the Mengjin Coalfield, Henan Province, China." Applied Mechanics and Materials 448-453 (October 2013): 1062–65. http://dx.doi.org/10.4028/www.scientific.net/amm.448-453.1062.
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Coal is a continuous unconventional gas reservoir and coal bed methane has the potential to make an important contribution to the future energy demands. The second member coal seam of Shaxi Formation in the Mengjin coalfield is one of the most important methane bearing and exploration formations. Based on industrial analysis, elemental analysis and methane content test of thirty-five coal samples from the Mengjin coalfield, together with other geological data of the past five-year exploration, the factors that controlling the coal bed methane reservoir are identified in the Mengjin coalfield. The thick-bedded No. 2 coal seam, about 6 meters, of the Shaxi formation are continuous distributed in the Mengjin coalfield. The burial depth is from 400 to 800 meters, this is suitable for coal bed methane exploit. There is a trend which an increase in the degree of coalification is correlated with rise content of methane in No. 2 coal. Coal rank has a significant effect on the content of coal bed methane. The relationships between methane content and basin hydrodynamics are also described and discussed in this paper. The deep stagnant zone contains the largest coal bed methane accumulation. Future geological exploration for coal bed methane in Mengjin coalfield should be guided by the essential factors identified in this study. The application of them could benefit to solving the discrepancy between the amount of reserves and the question of their exploitability.
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KABE, Toshiaki, Osamu NITOH, Yaeko KABE, Shugen KIM, Yoshiki SUKIGARA, and Minoru TAKEUCHI. "Studies on coal liquefaction mechanism. Part 6. Structural analysis and nitrogen content of coal liquid." Journal of The Japan Petroleum Institute 29, no. 2 (1986): 138–42. http://dx.doi.org/10.1627/jpi1958.29.138.
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Baolin, Tian, Wang Shijun, Guo Yingting, Li Hongqi, and Chen Guiren. "Flora of Palaeozoic coal balls of China." Journal of Palaeosciences 45 (December 31, 1996): 247–54. http://dx.doi.org/10.54991/jop.1996.1240.
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The geographic distribution of coal balls of China and their stratigraphic range are very wide. Fossil plants in coal balls are abundant Floras of coal balls of Jingyuan Gansu contain the same content as those of the Hauptfloz coal of Ruhr and the Kokfloz coal of Ostrau (Namur C) in Europe. Coal balls of Shanxi and Shandong (P1) are abundant and highly diversified with flourished Cathaysian flora, while in the coal balls of Shuicheng, Guizhou (the top of Upper Permian) the Cathaysian flora somewhat declines and shows less in diversification. Some Mesozoic coloured elements have also been observed.
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Hong, Chen, Qi Hui, and Long Ru-yin. "Content and structure of China coal mine operators’ psychological contract." Procedia Earth and Planetary Science 1, no. 1 (September 2009): 1617–26. http://dx.doi.org/10.1016/j.proeps.2009.09.249.
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Mullins, Oliver C., Sudipa Mitra-Kirtley, Jan Van Elp, and Stephen P. Cramer. "Molecular Structure of Nitrogen in Coal from XANES Spectroscopy." Applied Spectroscopy 47, no. 8 (August 1993): 1268–75. http://dx.doi.org/10.1366/0003702934067991.
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Five major nitrogen chemical structures, present in coals of varying ranks, have been quantitatively determined with the use of nitrogen x-ray absorption near-edge spectroscopy (XANES). Similar studies of the sulfur chemical structures of coals have been performed for the last ten years; nitrogen studies on these fossil-fuel samples have only recently been realized. XANES spectra of coals exhibit several distinguishable resonances which can be correlated with characteristic resonances of particular nitrogen chemical structures, thereby facilitating analysis of these complicated systems. Many model compounds have been examined; for some, the relative peak positions are explained in terms of the orbital description of the lone pair of electrons. All features in the XANES spectra of coals have been accounted for; thus, all the major structural groups of nitrogen present in coals have been determined. A wide variety of aromatic nitrogen compounds is found in the coals; no evidence of saturated amine is found. Pyrroles, pyridines, pyridones, and aromatic amines are found in coal; of these, pyrrolic structures are the most prevalent. Pyridine nitrogen is prevalent in all except low-rank coals. The low pyridine content in low-rank (high-oxygen) coals correlates with a large pyridone content. This observation suggests that, with increasing maturation of coal, the pyridone loses its oxygen and is transformed into pyridine. Aromatic amines are present at low levels in coals of all rank. The spectral effects of aromatic amines are shown by comparing the XANES spectra of coal and petroleum asphaltenes.
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Kong, Xianglu, Song Yang, Shoujun Liu, Kaixia Zhang, Tingting Jiao, and Ju Shangguan. "Study on Coupling Effect of Additives on NOx Control in Coal Pyrolysis-Combustion." E3S Web of Conferences 290 (2021): 03029. http://dx.doi.org/10.1051/e3sconf/202129003029.
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A large amount of nitrogen oxides produced by loose coal combustion has an important impact on the ecological environment. To solve this problem, it is proposed to prepare clean coke instead of loose coal combustion to reduce the emission of nitrogen oxides from civil coal combustion. Clean coke is prepared by pyrolysis raw coal adding additives, and the gas generated by pyrolysis is collected uniformly, thus avoiding the emission problem in the process of loose burning. In addition, the clean fuel catalyzes the reduction of nitrogen oxides to produce N2 in the combustion process, thus reducing the emission of combustion nitrogen oxides. In this paper, the additives were investigated, and finally it was found that loading 1 wt.% Fe and Ni had a better effect of decrease nitrogen content in coke through pyrolysis of coal and denitrification during the combustion of coke, and had a coupling effect on nitrogen oxide control in the pyrolysis-combustion process.
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Wang, Chang’an, Pengqian Wang, Lin Zhao, Yongbo Du, and Defu Che. "Experimental Study on NOx Reduction in Oxy-fuel Combustion Using Synthetic Coals with Pyridinic or Pyrrolic Nitrogen." Applied Sciences 8, no. 12 (December 5, 2018): 2499. http://dx.doi.org/10.3390/app8122499.
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Oxy-fuel combustion technology can capture carbon dioxide (CO2) in the large-scale and greatly lower nitrogen oxides (NOx) emission in coal-fired power plants. However, the influence of inherent minerals on NOx reduction still remains unclear and the impact of oxy-fuel combustion on the transformation of different nitrogen functional groups has yet to be fully understood. The present work aims to obtain a further understanding of the NOx reduction during oxy-fuel combustion using synthetic coals with pyrrolic or pyridinic nitrogen. Compared to pyridinic nitrogen, more of the pyrrolic nitrogen in synthetic coal was converted to NOx. The conversion ratio of nitric oxide (NO) first increased significantly with the rising oxygen content and then trended to an asymptotically constant as the oxygen (O2) content varied between 10–50%. The nitrogen dioxide (NO2) formation was roughly proportional to the oxygen content. The NO2 conversion was increased with particle size but the case of NO showed a non-monotonic variation. The catalytic effects of sodium carbonate (Na2CO3), calcium carbonate (CaCO3), and ferric oxide (Fe2O3) on the transformation of pyridinic nitrogen to NO were independent of the combustion atmosphere, while the alteration from air to the oxy-fuel combustion led to a change of mineral catalytic effect on the oxidation of pyrrolic nitrogen within the coal matrix.
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Portola, V. A., A. A. Bobrovnikova, S. A. Sin, and V. G. Igishev. "Special Features of the Release of Indicator Fire Gases at the Nitrogen Supply to the Foci of Coal Spontaneous Combustion." Occupational Safety in Industry, no. 4 (April 2022): 47–52. http://dx.doi.org/10.24000/0409-2961-2022-4-47-52.
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The most common method for monitoring the processes of spontaneous combustion of coal in the mines is the analysis of the composition of the mine atmosphere to detect gases released from coal when the temperature rises. Carbon monoxide and hydrogen are usually used as the main indicators. In recent years, nitrogen is widely used to prevent and extinguish the underground fires. It reduces the oxygen concentration in the fire area and can affect the indicator gases release. To study this effect, the samples of coal with a fraction of 1–3 mm, and the samples of coal dust with a particle size of 0.2–0.4 mm were used. Nitrogen with an admixture of oxygen was supplied to the heated samples. Studies showed that the carbon monoxide and hydrogen are released from the coal dust much more intensively than from the coal. Therefore, high concentrations of these indicator gases may point to the spontaneous combustion of the coal dust. As the proportion of oxygen in the mixture with nitrogen decreases, the release of carbon monoxide and hydrogen from the heated samples of coal and coal dust decreases. This can make it difficult to assess the state of spontaneous combustion foci in an inert environment. To determine the coal temperature when nitrogen with different oxygen content is supplied, the ratio of carbon monoxide and hydrogen concentrations can be used. In the coal dust it turns out to be the same as in the coal only at 3 % oxygen content. With an increase in the oxygen concentration, this ratio for the coal dust changes significantly. This fact can be used for the identification of fire foci.
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Zhao, Qiao Jing, Yue Gang Tang, Xiu Jie Deng, and Xiao Lei Yu. "Geochemistry of Sulfur in Extract from Hedong Coal Mine, China." Advanced Materials Research 734-737 (August 2013): 89–94. http://dx.doi.org/10.4028/www.scientific.net/amr.734-737.89.
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The organosulfur compounds in the extract of the unusually organic sulfur rich of Hedong coal mine had been identified by gas chromatography and mass spectrometry. There are two series organosulfur compounds (OSC) were detected in the extract, they are benzonaphthothiophen and dibenzothiophene and the content of methylbiphenyl is overwhelming advantages in the biphenyl series. It demonstrates that the coal was formed in alkaline environment. The coal was formed in a reduction environment generally but there are exceptions, the samples HD9-2 and HD10-13 which have the value of Pr/Ph was 3.52 and 4.05 and So/St in sample HD9-2 was 78.82%, 73.08% in sample HD10-13 respectively . It show that the coal suffer strong oxidation and there are no good correlation between the content of organic sulfur and the oxidation environment.
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Xu, Chuanlong, Haoyu Chen, Yong Yan, and Shimin Wang. "Determination of nitrogen content in coal through UV Differential Optical Absorption Spectroscopy." Fuel 151 (July 2015): 73–82. http://dx.doi.org/10.1016/j.fuel.2015.01.011.
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Wu, Dun, Wenyong Zhang, Guijian Liu, Run Zhan, and Guangqing Hu. "Characteristics and geological significance of germanium in Taiyuan coal formation of Huainan Coalfield, Anhui, China." International Journal of Coal Science & Technology 7, no. 4 (November 24, 2020): 662–75. http://dx.doi.org/10.1007/s40789-020-00382-5.
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AbstractHN-1# is the first fully working coring well of the Taiyuan Formation (Ty) in the Huinan Coalfield and exploration studies are currently underway on the associated resources of the coal-bearing strata. The HN-1# well is located in the Fufeng thrust nappe structural belt in the south of the Huainan Coalfield. Three coal samples from the Ty were collected from HN-1# and inductively-coupled plasma mass spectrometry and inductively-coupled plasma atomic emission spectrometry were used to determine the Ge content of each sample. Based on proximate and ultimate analyses, microscopy data, and analyses of the ash products, some important findings were made. The Ty coal samples had a relatively high total sulfur (St,d) content (4.24%), thus the coal was considered to be a lower ranked coal (high volatility bituminous coal), which also had a low coal ash composition index (k, 1.87). Collodetrinite was the main submaceral of the Ty coal. Small amounts of pyrite particles were found in the coal seams of the Ty, while the contents of pyrite and algae in the top and bottom sections of the coal seam were relatively high, which meant that the swampy peat conditions which existed during the formation of the coal seams were affected by seawater; also the degree of mineralization of the coal seam was relatively high, which is consistent with reducing conditions in a coastal environment setting. Atomic force microscopy (AFM) experiments showed that the modes of occurrence of Ge in the Ty coal were mainly those for organic-bound and adsorbed Ge species. The organic carbon isotope values for the Ty coal ranged from − 24.1‰ to − 23.8‰, with an average value of − 24.0‰, which is equivalent to the value for terrestrial plants (average value − 24.0‰). The Ge content of the Ty coal was 13.57 mg/kg. The Ge content was negatively correlated with volatile matter and the ash yield.
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Zhang, Lei, Naj Aziz, Ting Ren, Jan Nemcik, and Shihao Tu. "Nitrogen Injection To Flush Coal Seam Gas Out Of Coal: An Experimental Study." Archives of Mining Sciences 60, no. 4 (December 1, 2015): 1013–28. http://dx.doi.org/10.1515/amsc-2015-0067.
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Abstract Several mines operating in the Bulli seam of the Sydney Basin in NSW, Australia are experiencing difficulties in reducing gas content within the available drainage lead time in various sections of the coal deposit. Increased density of drainage boreholes has proven to be ineffective, particularly in sections of the coal seam rich in CO2. Plus with the increasing worldwide concern on green house gas reduction and clean energy utilisation, significant attention is paid to develop a more practical and economical method of enhancing the gas recovery from coal seams. A technology based on N2 injection was proposed to flush the Coal Seam Gas (CSG) out of coal and enhance the gas drainage process. In this study, laboratory tests on CO2 and CH4 gas recovery from coal by N2 injection are described and results show that N2 flushing has a significant impact on the CO2 and CH4 desorption and removal from coal. During the flushing stage, it was found that N2 flushing plays a more effective role in reducing adsorbed CH4 than CO2. Comparatively, during the desorption stage, the study shows gas desorption after N2 flushing plays a more effective role in reducing adsorbed CO2 than CH4.
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Zhao, Yu Ji, Jun Qian Li, Yi Dong Cai, Da Meng Liu, and Yan Bin Yao. "Preliminary Evaluation on Physical Properties of Coal Reservoirs in Boli Basin, Northeastern Heilongjiang Province, China." Advanced Materials Research 356-360 (October 2011): 2963–69. http://dx.doi.org/10.4028/www.scientific.net/amr.356-360.2963.
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The Boli basin has coalbed methane (CBM) resource of 57×108m3 at a coal-bearing area of about 7200km2. Although the basin has huge CBM development potential, the study on the characteristics of coal reservoirs is still deficient. In the paper, the physical properties (including coal petrography, rank, quality, porosity and permeability) of the coals were studied by: (1) measuring vitrinite reflectance, coal maceral composition and coal quality; (2) quantitatively counting microfractures; (3) porosity and permeability tests; and (4) low-temperature N2 isotherm adsorption/desorption and mercury porosimetry analyses. Results show that: (1) coal maceral composition is dominated by vitrinite (77.0-95.1 %); (2) the maximum vitrinite reflectance of coals ranges from 0.48 to 1.76 % Ro, max; (3) coal is composed of high carbon content (63.43-85.14%), low hydrogen content (3.23-4.56%), extremely low moisture content (0.18-1.18%) and widely varied ash yield (7.54 to 29.23%); (4) Coal pores are dominated by micropores (40.6-69.3%), and the pores with a diameter of 0-10nm are dominant (59.6-80.9%); (5) coal permeability values vary from 0.04 to 3.92mD with an average of 1.98mD. In addition, according to the mercury porosimetry analysis, pore-fractures size distribution was summarized as four types: Types Ⅰ and Ⅲ are favorable for developing CBM and represent good pore-fracture structures.
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Kuziemska, Beata, Paulina Klej, and Joanna Trębicka. "Effect of different nickel soil contents on cock’s-foot yield and nitrogen, phosphorus and potassium contents." Ochrona Srodowiska i Zasobów Naturalnych 27, no. 1 (March 1, 2016): 15–21. http://dx.doi.org/10.1515/oszn-2016-0005.
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AbstractThis study assessed the influence of liming and waste organic materials on the yield and nitrogen, phosphorus and potassium contents in cock’s-foot (Dactylis glomerata L.) grown on nickel-contaminated soil in the third year of a pot culture experiment. In the experiment, the following factors were taken into consideration: (1) nickel soil contamination (0, 75, 150 and 225 mg Ni·kg−1 of soil); (2) liming (0 Ca and Ca according to 1 Hh of soil) and (3) organic materials (no waste organic materials added, brown coal from a coal mine in Turów and rye straw). Introducing nickel into the soil, regardless of its amount, caused a significant decrease in the total yield of cock’s-foot and increased the nitrogen and potassium contents. Liming caused a significant increase in the yield of cock’s-foot and decrease its potassium content, but it did not clearly differentiate the nitrogen and phosphorus content. The used organic materials (straw and brown coal) caused a decrease in the phosphorus content in the grass biomass.
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Peng, Dan, Ben Wang, Xingfei Cai, and Lei Bei. "Research on the Modification of Coal Adaptability and Carbon Emissions Reduction Technology for Coal-Fired Boilers." Energies 15, no. 24 (December 15, 2022): 9533. http://dx.doi.org/10.3390/en15249533.
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In order to solve the problems of the high temperature of flue gas, low boiler efficiency, and the high concentration of nitrogen oxide (NOx) emissions for a 330 MW boiler fired with lean coal in a power plant, an adaptation modification by using different type of coals in the power generation unit (including pulverizing system, burners, heating surface, and so on) was carried out. The performances of boilers were tested under different combustion conditions before and after the modification. The results of the test show that the volatile content is higher and easy to burn out, and the combustible content of fly ash and slag are greatly reduced after the change in coal type (while lean coal is changed into bituminous coal). At the same time, the low-temperature economizer can greatly reduce the flue gas temperature, thus increasing the efficiency from 90.36% (lean coal, corrected) to 92.71% (bituminous coal). After the change in coal type (lean coal to bituminous coal) and the shift to low-nitrogen combustion (using low-nitrogen burner and OFA technology), the flame temperature in the main combustion area of the boiler decreases, the thermal-type NOx is reduced, and the volatile content of bituminous coal is higher in the anoxic atmosphere of the main combustion zone where the excess air coefficient is small. The intermediate reductive products tend to produce more, which can restrain and reduce NOx. Therefore, the concentration of NOx emissions can be greatly reduced. NOx average emissions at the economizer outlet decreased by 68%, from 864 mg/Nm3 to 279.4 mg/Nm3. A low-temperature economizer uses waste heat to heat feed water, which reduces coal consumption by about 1.32 g/(kW·h). The coal consumption for power supply after modification is reduced by 9.83 g/(kW·h) and the annual energy saving is 16,776 tons of standard coal, while the total carbon dioxide emissions reduction is 41,213.60 tons after the unit modification.
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Li, Xiaoshi, Yiwen Ju, Quanlin Hou, Zhuo Li, Mingming Wei, and Junjia Fan. "Characterization of Coal Porosity for Naturally Tectonically Stressed Coals in Huaibei Coal Field, China." Scientific World Journal 2014 (2014): 1–13. http://dx.doi.org/10.1155/2014/560450.
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The enrichment of coalbed methane (CBM) and the outburst of gas in a coal mine are closely related to the nanopore structure of coal. The evolutionary characteristics of 12 coal nanopore structures under different natural deformational mechanisms (brittle and ductile deformation) are studied using a scanning electron microscope (SEM) and low-temperature nitrogen adsorption. The results indicate that there are mainly submicropores (2~5 nm) and supermicropores (<2 nm) in ductile deformed coal and mesopores (10~100 nm) and micropores (5~10 nm) in brittle deformed coal. The cumulative pore volume (V) and surface area (S) in brittle deformed coal are smaller than those in ductile deformed coal which indicates more adsorption space for gas. The coal with the smaller pores exhibits a large surface area, and coal with the larger pores exhibits a large volume for a given pore volume. We also found that the relationship betweenSandVturns from a positive correlation to a negative correlation whenS>4 m2/g, with pore sizes <5 nm in ductile deformed coal. The nanopore structure (<100 nm) and its distribution could be affected by macromolecular structure in two ways. Interconversion will occur among the different size nanopores especially in ductile deformed coal.
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Wang, Sheng-Cheng, Ya-Nan Gao, Lan-Ying Huang, Hai-Jian Li, and Shan-Jie Su. "A novel triaxial apparatus to evaluate the effect of high temperature nitrogen injection concept and design." Thermal Science 25, no. 6 Part B (2021): 4527–35. http://dx.doi.org/10.2298/tsci2106527w.
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High temperature nitrogen, injection into coal seams is supposed to improve the per?meability and thus maintain the safety of underground mining. A novel triaxial appa?ratus is recently developed, aiming at providing the effective method to evaluate the effect of high temperature nitrogen injection. The main feature of this novel appara?tus is its high confining pressure, gas injection with high pressure as well as the high temperature. This new device can be either used for natural coal samples (e.g. intact or fractured) or the synthetic coal samples. A series of leakage tests were conducted to verify the feasibility of this instrument, the results of which have confirmed that the maximum pressure (i.e. 10 MPa) can be reached. In addition, the high temperature and pressure of nitrogen gas can also be sustain at the requested level. Based on the preliminary tests on the instrument, a large amount of tests were carried out to eval?uate the effect of nitrogen injection in enhancing the permeability of coking coal from the Pingdingshan coalfield, China, and the influence of high temperature nitrogen injection on mechanical parameters of coal was obtained.
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Gil, Stanisław, Wojciech Bialik, and Sławomir Kozłowski. "Generation of Nitrogen Oxides in Submerged Arc Furnace during the Production of Ferroalloys." Advances in Thermal Processes and Energy Transformation 4, no. 3 (2021): 37–41. http://dx.doi.org/10.54570/atpet2021/04/03/0037.
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The paper presents the method of selection of hard coals applied in reducing mixtures used in ferroalloy production technologies. The graphical relationship between reflectivity and reactivity towards SiO as well as reflectivity and the content of hard carbon Cfix has been presented. The use of hard coal in place of coke is associated with the release of significant amounts of volatiles contained in the coal. Increasing the amount of volatile matter may favor the increased generation of NOx from the fuel mechanism due to the nitrogen content in the organic matter of coal. The influence of the thermal mechanism of NOx generation may be limited due to contradictory phenomena. On the one hand, it is possible to have a higher calorimetric combustion temperature of post-reaction gases (due to the content of coal degassing products), and on the other hand, reducing the amount of energy released from SiO afterburning (less SiO due to higher silicon yields). The higher yield of silicon is related to the higher reactivity of appropriately selected hard coals. The mechanisms of NOx formation were presented together with measurements made during the production of the most popular ferroalloy FeSi75. Measurements were carried out along the two axes P1 and P2 in the furnace hood at three distances from the center of the pitch diameter of the electrodes.
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Yu, Jiang Long, Fang Rui Meng, Xian Chun Li, and Arash Tahmasebi. "Power Generation from Coal Gangue in China: Current Status and Development." Advanced Materials Research 550-553 (July 2012): 443–46. http://dx.doi.org/10.4028/www.scientific.net/amr.550-553.443.
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This paper provides an overview on the current status of power generation in China using coal gangue. The government regulation towards the use of coal gangue for power generation is introduced. Emission of pollutants and low thermal power plant efficiency are the two major problems for the power industry firing coal gangue. Particulate matter emission control is a problem due to the high ash content. Sulfur emissions from these units are easily controlled mostly through lime/limestone injection and in-situ capture. Overall, efficient power generation using coal gangue is a promising approach to reduce the use of coal resources and reduce the environmental impacts.
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Zhao, Gang Wei, and Yun Han Xiao. "Study on Brown Coal Pyrolysis." Advanced Materials Research 524-527 (May 2012): 894–97. http://dx.doi.org/10.4028/www.scientific.net/amr.524-527.894.
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It is very important to the combustion processes of coal pyrolysis, so the effects of all reaction condition on the brown coal (Yunnan,China) were investigated by using the fixed bed reactor in detail. Through the new method of part-hydrogenation of the pyrolysis, it can be increased the content of coal tar at the same time reduced H2consumption.
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Wang, Xiaofei, Hanliu Wang, He Jing, Wei-Ning Wang, Weidong Cui, Brent J. Williams, and Pratim Biswas. "Formation of Nitrogen-Containing Organic Aerosol during Combustion of High-Sulfur-Content Coal." Energy & Fuels 31, no. 12 (November 15, 2017): 14161–68. http://dx.doi.org/10.1021/acs.energyfuels.7b02273.
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Wang, Shuai, Xin Lu Feng, Jun Zhou, and Xue Mei Wang. "Fourier Transform Near Infrared Spectroscopy Analysis of Power Plant Coal Quality." Advanced Materials Research 236-238 (May 2011): 799–803. http://dx.doi.org/10.4028/www.scientific.net/amr.236-238.799.
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Studied the correlation of near-infrared spectra data and six coal indices, found ash and calorific value has low correlations with spectra data; then use dynamic principal components PLS method predict the coal index; this method could predict Volatile and Hydrogen content better, however, the ability to predict Carbon content and Nitrogen content is lower. It is found that using reflection spectroscopy analyzes the coal need a strong energy source, because the color of coal is deep and reflection is very weak, this leads to noisy signals. Only by improving the energy source could solve the problem of poor spectra data fundamentally; spectral data mining cannot fundamentally improve the quality of data. The current near-infrared reflection spectroscopy common platform such as BRUKER is not suitable for coal analysis, analysis of coal to be better need to develop special near-infrared measuring instruments.
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Su, Yinjiao, Xuan Liu, Yang Teng, and Kai Zhang. "A Preliminary Study on Dependence of Mercury Distribution on the Degree of Coalification in Ningwu Coalfield, Shanxi, China." Energies 14, no. 11 (May 27, 2021): 3119. http://dx.doi.org/10.3390/en14113119.
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Mercury (Hg) is a toxic trace element emitted from coal conversion and utilization. Samples with different coal ranks and gangue from Ningwu Coalfield are selected and investigated in this study. For understanding dependence of mercury distribution characteristics on coalification degree, Pearson regression analysis coupled with Spearman rank correlation is employed to explore the relationship between mercury and sulfur, mercury and ash in coal, and sequential chemical extraction method is adopted to recognize the Hg speciation in the samples of coal and gangue. The measured results show that Hg is positively related to total sulfur content in coal and the affinity of Hg to different sulfur forms varies with the coalification degree. Organic sulfur has the biggest impact on Hg in peat, which becomes weak with increasing the coalification degree from lignite to bituminous coal. Sulfate sulfur is only related to Hg in peat or lignite as little content in coal. However, the Pearson linear correlation coefficients of Hg and pyritic sulfur are relatively high with 0.479 for lignite, 0.709 for sub-bituminous coal and 0.887 for bituminous coal. Hg is also related to ash content in coal, whose Pearson linear correlation coefficients are 0.504, 0.774 and 0.827 respectively, in lignite, sub-bituminous coal and bituminous coal. Furthermore, Hg distribution is directly depended on own speciation in coal. The total proportion of F2 + F3 + F4 is increased from 41.5% in peat to 87.4% in bituminous coal, but the average proportion of F5 is decreased from 56.8% in peat to 12.4% in bituminous coal. The above findings imply that both Hg and sulfur enrich in coal largely due to the migration from organic state to inorganic state with the increase of coalification degree in Ningwu Coalfield.
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Li, Bo, Chaohui Zong, Laisheng Huang, Yongjie Ren, and Xiaoquan Lv. "Study on the Influence of Liquid Nitrogen Cold Soaking on the Temperature Variations and Seepage Characteristics of Coal Samples with Different Moisture Contents." Geofluids 2021 (October 19, 2021): 1–10. http://dx.doi.org/10.1155/2021/8924016.
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Due to its advantages such as environmental friendliness and remarkable permeability enhancement effect, the technology of liquid nitrogen cold soaking (LNCS) cracking coal has become a hot spot in the research on coal seam permeability enhancement in recent years. The frost heave force generated by water-ice phase transformation and the temperature stress are the main mechanisms of LNCS cracking water-containing coal. This paper focuses on the effect of LNCS on the temperature variations and seepage characteristics of coal. To further this purpose, the temperature measurement test and the permeability test were conducted on coal samples with different moisture contents under LNCS, respectively. In addition, by comparing the computer tomography test results of coal samples before and after LNCS, the internal pore structure changes of coal samples were further analyzed from a three-dimensional perspective. The test results show that the coal sample with a higher moisture content consumes a shorter time to reach internal temperature equilibrium and experiences faster temperature changes. LNCS can enhance coal permeability, and the growth rate of permeability increases exponentially with the increase of moisture content. After the LNCS treatment, the dried coal sample is mainly sprouting new pores on the basis of primary pores; in contrast, for water-containing coal samples, new pores are sprouted while primary pores will penetrate each other spatially to form a fracture network. In the process of LNCS, moisture has a significant effect on the seepage characteristics of coal, so appropriately increasing the moisture content of the coal seam conduces to achieving a better permeability enhancement effect.
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Pang, Ming Xiang, Xue Zhen Cheng, Xiao Chao Qian, and Mao Yong Cao. "A Measuring Water Content Method Based on K-RBF Neural Network in the Coal on Transportation Belt." Applied Mechanics and Materials 121-126 (October 2011): 2431–39. http://dx.doi.org/10.4028/www.scientific.net/amm.121-126.2431.
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In coal mines fire consists of one of the main disasters, which usually take place for the reason that the water content of coal is over low. Over low water content of the coal transported with belt more likely brings about flying coal dust, which, when accumulated to some degree, will triggers explosion. Given that in China now coal is mainly transported with belt in coal mines, the author in this paper proposes a way to measure water content of coal transported with belt by use of microwave attenuation method and improve the measure accuracy through RBF neural network algorithm. This method is proved to be scientifically reasonable through laboratory simulation and experimentation. The theoretical basis and technical support are provided to increase the accuracy measuring water content of coal transported with belt by this method.
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Li, Qingsong, Xin He, Jiahao Wu, and Shu Ma. "Investigation on coal seam distribution and gas occurrence law in Guizhou, China." Energy Exploration & Exploitation 36, no. 5 (February 20, 2018): 1310–34. http://dx.doi.org/10.1177/0144598718758068.
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In order to enhance the management level of coal mine safety production and promote the “safe, accurate and efficient” preventive treatments for gas in Guizhou of China, the occurrence and other prominent features of coal and gas are investigated. The characteristics and regularities of coal mine accidents in Guizhou during 2001–2015 are summarized to analyze the commonness of gas accidents in general and determine the characteristics of gas preventive treatment. Geological data, gas basic parameters, and physical properties of coal of 386 mines and 761 sets of coal seams in Guizhou are also statistically analyzed. Based on step control theory of gas occurrence structure and the regionally tectonic regularity of coal-bearing stratum distribution, the deformations of coal measures in Guizhou mine area are mainly caused by great variation of stratigraphic occurrence, complicated geological structure, and high crustal stress. The regional occurrence of coal seam is obvious with the highest content of Tongzi–Zunyi–Liuzhi–Xingyi line, which gradually reduces to the both east and west sides. Influence factors and weights of gas occurrence are expounded from geological and coal factor by mathematical statistics, and the main influence factors of gas occurrence are the sedimentary environment, syncline structure, and metamorphic grade in proper sequence. Combined with the risk prediction of coal and gas outburst area, the prediction of gas pressure by gas content is not suitable under the special occurrence conditions. The initial velocity of gas emission, the solidity coefficient, and the damage type in more than 77% of minable seams all exceed the critical value. This work provides guidance in improvement of the governance situation for gas control in Guizhou. The index prediction system which is suitable for mining conditions of special coal mines in Guizhou should be established.
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Wang, Shengcheng, Haijian Li, and Lanying Huang. "Permeability Evolution of Naturally Fractured Coal Injected with High-Temperature Nitrogen: Experimental Observations." Processes 9, no. 2 (February 3, 2021): 296. http://dx.doi.org/10.3390/pr9020296.
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The permeability of more than 70% of coal seams in China is less than 1 mD, creating difficulties in recovering underground coal methane. Therefore, a new technology of high-temperature nitrogen (HTN2) injection into the coal seam was proposed to improve the coal permeability and gas extraction rate. In this paper, the effects of the N2 temperature, injection pressure and cycle number on the permeability of naturally fractured coking coal has been investigated. When HTN2 was injected into coal samples, the results indicated that the permeability decreased over time in the beginning, suddenly increased to a large value, and was subsequently maintained in a relatively stable range. The maximum permeability ratio increased with the rise of the N2 temperature and injection pressure. An analysis indicated that the increase of coal permeability was the result of the increase of the global coal strain caused by thermal expansion and the adsorption-induced expansion. The maximum permeability ratios in various cycles of multicycle N2 injection into the coal sample were all greater than 1.0 while progressively declining. Obviously, the alternating stress was conducive to the further expansion of the coal fractures to increase the coal permeability. However, on the basis of the first period of expansion, re-expansion was difficult and required more energy. The effects of multicycle N2 injection on coal permeability have been considerably improved when compared with N2 injection with only one cycle. The research results are helpful for rapidly extracting methane and guaranteeing mine safety.