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Kotik, O. S., N. V. Pronina, N. S. Inkina i P. A. Beznosov. "Composition Peculiarities of the Upper Devonian Coaly Rocks (The Sula River Section, North Timan)". Литология и полезные ископаемые, nr 5 (1.09.2023): 499–514. http://dx.doi.org/10.31857/s0024497x23700192.
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A detailed coal-petrographic and mineralogical-geochemical study of humic coals and coaly rocks in the Sargaev deposits of the Upper Devonian of the Northern Timan (Sula River), which is an example of the burial of the most ancient coal-forming plants, has been carried out. The following types of organic rocks are identified in the section: “jet-like” coal, liptobiolitic silty-clayey coal, and silty-clayey-coaly mixtolites. The studied coals and coaly rocks are composed of humic organic components, represented by vitrinite and liptinite macerals, the inertinite group is of subordinate importance. Vitrinite macerals include gelinite, collotelinite, and telinite (xylenite), liptinite macerals include sporinite, cutinite, liptodetrinite, bituminite, alginite, and a resinous substance, and inertinite macerals include inertodetrinite, semifusinite, fusinite, and funginite. The level of organic matter maturity according to the vitrinite reflectance RV = 0.45–0.55%, corresponds to the transition from proto- to meso-catagenesis (gradations PC3–MС1). The mineral component of mixtolites and high-ash coals consists of kaolinite, chlorite/smectite (with a predominance of the chlorite component) and quartz.
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Zhou, Guoxiao, Guoqi Wei i Guoyi Hu. "The geochemical and organic petrological characteristics of coal measures of the Xujiahe formation in the Sichuan Basin, China". Energy Exploration & Exploitation 37, nr 3 (8.04.2019): 889–906. http://dx.doi.org/10.1177/0144598719842332.
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Upper Triassic coaly and lacustrine source rocks complicate efforts to determine the source of hydrocarbons in Sichuan Basin. Total organic carbon analyses, pyrolysis experiments, petrological examinations, and gas chromatography and gas chromatography–mass spectrometry determinations were conducted on coals, carbonaceous mudstones and mudstones collected from two outcrop sections and cores of nine wells. Results revealed that the abundant organic carbon content will prolong the hydrocarbon generation cycle for coals and then the hydrocarbon generating capacity of coals will be enhanced by salinization, thereby contributing bacteria and algae microorganisms into humic coal of the Xujiahe Formation. Compared with mudstone, coal with the same maturity has a stronger adsorption effect on free hydrocarbons. When Ro is greater than 1.35, coal still has a strong hydrocarbon generation ability. The stable water column stratification and euxinic bottom water conditions are evidenced from the lower Pr/Ph and the higher gammacerane indices. The mixing of sea water has been proven by the existence of 4α,23,24,-trimethylcholestanes.
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Feng, Songbao, Qiang Wei i Xianqing Li. "Chemical Composition Variations of Altered and Unaffected Coals from the Huaibei Coalfield, China: Implications for Maturity". Energies 14, nr 11 (24.05.2021): 3028. http://dx.doi.org/10.3390/en14113028.
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The composition characteristics of altered coals in the Huaibei Coalfield, China, was investigated through a comparative analysis between altered and unaffected coals from the Wolonghu, Taoyuan and Renlou coal mines. Results indicated that the altered coals in Wolonghu coal mine are mostly anthracite coals, with a maximum vitrinite reflectance of 1.6–3.9% (average of 2.9%). Coals from Wolonghu coal mine were mainly consisted of vitrinite (66.2–97.0%), followed by inertinite (2.0–4.0%) and exinite (0.4–6.9%). Differences in volatile matter content were observed between the altered coals in Wolonghu coal mine and unaffected coals from neighboring coal mines, implying that the chemical composition and maturity of coals were changed after magmatic alteration. In addition, differences in hydrogen element were noted among the coals from Wolonghu, Renlou and Taoyuan coal mines, and the phenomenon of “deficient in hydrogen element” was observed in Wolonghu coals. The aliphatic hydrocarbon structure parameters suggested that the aliphatic chain lengths of Wolonghu coals are shorter than those of coal samples from the Renlou and Taoyuan coal mines. In addition, maturity is positively correlated with hydrogen enrichment degree, but negatively related with aliphatic hydrocarbon structure. Coals from Renlou and Taoyuan coal mines showed great weight loss with various heating rates at temperatures of 0–1000 °C, whereas those from Wolonghu coal mine had less weight loss.
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El-Tawil, Asmaa A., Bo Björkman, Maria Lundgren, Frida Bäck i Lena Sundqvist Ökvist. "Influence of Modified Bio-Coals on Carbonization and Bio-Coke Reactivity". Metals 12, nr 1 (28.12.2021): 61. http://dx.doi.org/10.3390/met12010061.
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Substitution of coal in coking coal blend with bio-coal is a potential way to reduce fossil CO2 emissions from iron and steelmaking. The current study aims to explore possible means to counteract negative influence from bio-coal in cokemaking. Washing and kaolin coating of bio-coals were conducted to remove or bind part of the compounds in the bio-coal ash that catalyzes the gasification of coke with CO2. To further explore how the increase in coke reactivity is related to more reactive carbon in bio-coal or catalytic oxides in bio-coal ash, ash was produced from a corresponding amount of bio-coal and added to the coking coal blend for carbonization. The reaction behavior of coals and bio-coals under carbonization conditions was studied in a thermogravimetric analyzer equipped with a mass spectrometer during carbonization. The impact of the bio-coal addition on the fluidity of the coking coal blend was studied in optical dilatometer tests for coking coal blends with and without the addition of bio-coal or bio-coal ash. The result shows that the washing of bio-coal will result in lower or even negative dilatation. The washing of bio-coals containing a higher amount of catalytic components will reduce the negative effect on bio-coke reactivity, especially with acetic acid washing when the start of gasification temperature is less lowered. The addition of bio-coal coated with 5% kaolin do not significantly lower the dilatation-relative reference coking coal blend. The reactivity of bio-cokes containing bio-coal coated with kaolin-containing potassium oxide was higher in comparison to bio-coke containing the original bio-coal. The addition of ash from 5% of torrefied bio-coals has a moderate effect on lowering the start of gasification temperature, which indicates that the reactive carbon originating from bio-coal has a larger impact.
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Scott, S. G., i P. Crosdale. "THE WALLOON COAL MEASURES—THE NEXT COAL SEAM GASTARGET?" APPEA Journal 40, nr 1 (2000): 86. http://dx.doi.org/10.1071/aj99006.
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The Queensland coal seam gas industry has grown over the last 12 years. During this time the vast majority of exploration wells have targeted the Late Permian coal measures in the Bowen and Galilee Basins. These formations have been the major target because they contain coals with a vitrinite reflectance ranging above 0.7%. This range has always been seen as the main period for methane generation.As well as containing vast quantities of Permian coal, Queensland also has vast quantities of Middle Jurassic coals within its Mesozoic Basins. These coals have received little-to-no exploration for their coal seam gas potential as they have always been interpreted as being immature for gas generation.Over 550 petroleum exploration wells drilled in the Mesozoic Surat Basin of eastern Queensland were reviewed to determine the coal volume of the intersected Walloon Coal Measures. A significant number have intersected large volumes of sub-bituminous to high volatile bituminous coals, in seams ranging up to 11.7 m in thickness. While the individual seams are not laterally persistent, the coal packages can be traced over hundreds of kilometres of the eastern Surat Basin.While only one well has tested the gas content, gas quality and saturation of the Walloon Coal Measures, numerous water bores have reported gas flows from the zone, and petroleum wells intersecting the formation have recorded high mud gas readings during drilling.The relatively shallow depth of the unit over much of the basin, the thickness of the coal packages, the proximity to major gas trunk pipelines and markets make the Walloon Coal Measures an ideal target for the next generation of coal seam gas explorers.
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Amangeldikyzy, A., A. N. Kopobayeva, G. G. Blyalova i N. S. Askarova. "Қарағанды көмір бассейні көмірінің геохимиялық мамандануы". Горный журнал Казахстана, nr 7(219) (8.08.2023): 15–20. http://dx.doi.org/10.48498/minmag.2023.219.7.008.
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There are over 300 coal basins and deposits known in Kazakhstan, the largest of them is the Karaganda Coal Basin. There is approximately a half of all industrial reserved of coal of Kazakhstan is located in its subsoils. The Karaganda Coal Basin is the forth in the CIS according to its size and coal reserves. Unique coal resources require a comprehensive and scientifi cally justifi ed approach to their research. This paper studies the impurity elements distribution pattern to assess the geochemical speciation of coals in the Karaganda Coal Basin. As a result of the research performed, it has been found that the basin is characterized by mainly lithophylous and weal chalcophilous (Te, Cu, Ga, Ge) speciation. Siderofylous association is represented by Co, Ag. In the basin coal, increased concentrations of Ba, Sr, U, Sm, As, Sb, Fe, Br, La, Ce, Th, Cr, Hf, Cs, Co, Sc are detected if compared to the coal clarke, which is conditioned by the provenance area of the coal accumulation basin Қазақстанда 300-ден астам көмір бассейндері мен кен орындары белгілі. Қарағанды көмір бассейнінің жер қойнауында Қазақстандағы барлық өнеркәсіптік көмір қорларының жартысына жуығы шоғырланған. Қарағанды көмір бассейні көлемі мен көмір қоры бойынша ТМД-да төртінші орында. Көмірдің бірегей ресурстары оларды зерттеуге кешенді және ғылыми негізделген тәсілді қажет етеді. Жұмыста Қарағанды көмір бассейні көмірінің геохимиялық мамандануын бағалау үшін қоспа элементтерінің таралу заңдылықтары зерттелді. Жүргізілген зерттеулер нәтижесінде бассейн негізінен литофильді және әлсіз халькофильді (Te, Cu, Ga, Ge) мамандандырумен сипатталатыны анықталды. Сидерофильді ассоциацияны Co, Ag ұсынады. Бассейн көмірінде көмір кларкімен салыстырғанда Ba, Sr, U, Sm, As, Sb, Fe, Br, La, Ce, Th, Cr, Hf, Cs, Co, Sc концентрациялары жоғарылаған, бұл көмірді сақтау бассейнінің қоректену аймағына байланысты В Казахстане известно свыше 300 угольных бассейнов и месторождений, из них наиболее крупнейшим считается Карагандинский угольный бассейн, в недрах которого сосредоточена примерно половина всех промышленных запасов угля в Казахстане. Карагандинский угольный бассейн занимает четвертое место в СНГ по величине и запасам угля. Уникальные ресурсы угля требуют комплексного и научно-обоснованного подхода к их изучению. В настоящей работе изучены закономерности распределения элементов-примесей для оценки геохимической специализации углей Карагандинского угольного бассейна. В результате проведенных исследований установлено, что для бассейна характерна преимущественно литофильная и слабая халькофильная (Te, Cu, Ga, Ge) специализация. Сидерофильная ассоциация представлена Co, Ag. В углях бассейна установлены повышенные по сравнению с угольным кларком концентрации Ba, Sr, U, Sm, As, Sb, Fe, Br, La, Ce, Th, Cr, Hf, Cs, Co, Sc, что обусловлено областью питания бассейна угленакопления
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Li, Hui, Xiaoling Song, Gang Li, Lingxue Kong, Huaizhu Li, Jin Bai i Wen Li. "Effect of Coal Blending on Ash Fusibility and Slurryability of Xinjiang Low-Rank Coal". Processes 10, nr 9 (26.08.2022): 1693. http://dx.doi.org/10.3390/pr10091693.
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This work investigated the effect of coal blending on ash fusibility and slurryability of Xinjiang low-rank coal. The results showed that Xinjiang low-rank coals were characterized by high internal water content, high volatile content, high ash fusing point, and poor slurryability, which can not be directly used in coal water slurry gasification. The blending method not only reduced the ash fusibility but also improved the slurryability of these low-rank coals. When the coals with low calcium and high silicon contents (KG and YK) were blended with coal with high calcium content (SH), the ash fusion temperatures of the blended coal were significantly reduced. Moreover, the SH coal showed the worst slurryability performance with a concentration of 48.56%. The slurryability of HS coal can be dramatically improved by blending with KG. When the mass fraction of KG coal reached 70%, the concentration of coal water slurry increased by 11%. For the blended coal of KG and YK, the concentration and stability of coal water slurry gradually increase with the increasing mass ratio of KG. The coal blending method can effectively improve the concentration of coal water slurry for the low-rank coals, which were difficult-to-prepare slurry.
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Kumar, Manish, i Hari Prakash Tiwari. "Efficient utilization of Indian Coking Coal: Opportunities and challenges". Metallurgical Research & Technology 117, nr 2 (2020): 209. http://dx.doi.org/10.1051/metal/2020017.
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The preservation of coking coal and the reduction of coke cost are gaining much importance in iron and steel industry. An effort is being made worldwide to maximize the use of inferior quality of coking coal in cokemaking without sacrificing the coke quality to minimize the coke cost. In general, Indian coking coals contain lower content of vitrinite (≤ 50%) and higher content of ash (≥ 15%) as compared to imported coking coal. Indian coking coals have poor washability characteristics also. Therefore, for making coal blend for coke making, selection of an appropriate proportion of Indian coking coals with imported coking coals is a major challenge for Indian steel industries. Proper selection of Indian coal not only reduces the coking coal import but also minimizes the coal blend cost with added benefits of the increase in the captive mine life. This paper touches the opportunities and challenges for efficient utilization of Indian coking coal as a component in the coal blend to produce the desired quality of coke.
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Zhang, Qiuli, Min Luo, Long Yan, Aiwu Yang i Xiangrong Hui. "Kinetic Analysis of Low-Rank Coal Pyrolysis by Model-Free and Model-Fitting Methods". Journal of Chemistry 2019 (11.11.2019): 1–7. http://dx.doi.org/10.1155/2019/9075862.
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Coal SJC, coal WJG, coal ZJM, and coal HCG were selected to investigate the pyrolysis kinetics of northern Shaanxi coals. TG and DSC experiments of four coals were carried out with a synchronous thermal analyzer at heating rates 5, 10, 15, and 20 C/min, respectively. The pyrolysis characteristics were described by thermogravimetric data, and the kinetic parameters were calculated by Flynn–Wall–Ozawa (FWO), Kissinger, general integration, and MacCallum–Tanner methods. The results show that coal SJC, coal ZJM, and coal HCG all conform to the reaction series equation, the thermal decomposition reaction rate is controlled by chemical reaction, and coal WJG conforms to Avrami–Erofeev equation. The activation energies of the four coals are 177.53 kJ/mol, 200.34 kJ/mol, 158.59 kJ/mol, and 240.47 kJ/mol, respectively.
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Ren, Wenying, Liu Yang, Qingyi Cao i Chaoming Liang. "Concentration, distribution and occurrence of mercury in Chinese coals". E3S Web of Conferences 290 (2021): 03003. http://dx.doi.org/10.1051/e3sconf/202129003003.
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Mercury in coals is one of the important sources of atmospheric mercury, which is potentially harmful to the ecological environment. Based on the data of 970 coal samples, the concentration, spatial distribution and occurrence of mercury in Chinese coals were analyzed. The main conclusions are as follows: The distribution of mercury concentration in Chinese coalfields is uneven; medium and high mercury coals are mainly distributed in southwest China and eastern Inner Mongolia. The mercury concentrations in various coal-forming periods are as follows: K (0.320 mg/kg) > P2 (0.220 mg/kg) > C3 (0.179 mg/kg) > J (0.177 mg/kg) > D (0.165 mg/kg) > P1 (0.136 mg/kg) > C1 (0.090 mg/kg) > E (0.086 mg/kg) > T3 (0.066 mg/kg). The mercury concentrations in different coal ranks are as follows: Lignite (0.164 mg/kg), long flame coal (0.078 mg/kg), non-caking coal (0.256 mg/kg), weakly caking coal (0.086 mg/kg), gas coal (0.151 mg/kg), fat coal (0.122 mg/kg), coking coal (0.171 mg/kg), lean coal (0.393 mg/kg), meagre coal (0.161 mg/kg), anthracite (0.160 mg/kg). Sulfide bound state is the main form of mercury in coals, and pyrite is the main occurrence medium.
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Neupane, Bhupati, i Bishow Raj Silwal. "Study of microstructure, maceral and mineral matter in two different coals of the Nepal Himalaya". Journal of Nepal Geological Society 56, nr 1 (28.06.2018): 9–17. http://dx.doi.org/10.3126/jngs.v56i1.22695.
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The Eocene coals from the western (Tosh coalfield) and central regions (Jhadewa coalfield) of the Nepal Himalaya have been studied under the petrological and the Scanning Electron Microscopes to explain the mode of occurrence of mineral matter and their microstructural relations with organic constituents. As shown by the results of the coal samples, three kinds of coals in diminishing abundance are moderately dull coal, moderately bright coal and bright coal. Distribution of mineral matter in the Eocene coals shows that the bright coal is rare in western Nepal and the moderately bright coal is abundant in central Nepal. Mineral matter in moderately dull coals contains superficial impregnating and cavity filling. Mineral matter in bright coals contains superficial mounting and pore fillings, but in moderately bright coals contains superficial impregnating, cavity filling, and intimate intergrowth. Mineral matters in
moderately dull coals, moderately bright coals and bright coals respectively range from 38.27 to 47.12 vol%, 12.31 and 15.73 vol%, and 12.31 and 15.73 vol%. The Jhadewa coalfield (central Nepal) contains more macerels than the Tosh coalfield (western Nepal), whereas the Tosh coalfield contains more mineral matter than the Jhadewa coalfield. The results indicate two different origins for coal deposits from two different regions.
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Kortenski, Jordan, i Anton Sotirov. "Occurrence and distribution of the siderophile elements in some Bulgarian coals". Geologica Balcanica 34, nr 3-4 (30.12.2004): 71–88. http://dx.doi.org/10.52321/geolbalc.34.3-4.71.
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Coals from fourteen Bulgarian basins and deposits were sampled. The siderophile elements Fe, Ni, Co, Mn, Cr, V, Ti and their distribution were studied in these samples. The coals have different rank and age. The studied lignite was taken from the Neogene Maritsa-West, Stanyantsi, Belibreg, Chukurovo, Sofia, Karlovo, Samokov, Kyustendil, Oranovo, Gabrovitsa, and Katrishte basins. Subbituminous coal was taken from the Paleogene Pernik Basin, bituminous coal was from the Eocene Suhostrel and Cenomanian Balkan Basins, and the Svoge Pensilvanian anthracite was also investigated. Most of the studied coals were rich in siderophile elements. Iron, Ni and Co have negative correlation with the coal ash in all coals with exception of Belibreg and Suhostrel coal. Titanium often has positive correlation with the coal ash, and Mn, Cr and V show mainly negative correlation with the ash. The following tendencies of the concentration and distribution of the siderophile elements in the studied coal were established: The concentrations of Ni and Co have similar distribution in the coal from all studied basins. The Fe has organic affinity in all studied coals and Ni and Co have organic affinity in all coals with an exception of Belibreg and Suhostrel coal. The Mn has organic affinity with an exception in the Belibreg, Chukurovo, Karlovo, Samokov, and Kyustendil coal. Cr has organic affinity with an exception of Belibreg, Chukurovo, Gabrovitsa, Kyustendil, Oranovo, and Katrishte coal. Vanadium has organic affinity in the Maritsa-West, Chukurovo, Karlovo, Sofia, Samokov, Gabrovitsa, Oranovo, and Pernik coal. Titanium has organic affinity in the Belibreg, Sofia, Karlovo, Kyustendil, and Svoge coal. The main factors for the accumulation of the siderophile elements in coals were: 1) location of the basins closely to metallogenic provinces or rocks around the basin with high concentrations of the elements; 2) good conditions for forming of organic and inorganic complexes in the ancient peat bog; 3) fracture and cleat of the coal seams in combination with the presence of infiltration solutions, which contained siderophile elements.
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Bukowska, Mirosława, Urszula Sanetra i Mariusz Wadas. "Zonation of deposits of hard coals of different porosity in the Upper Silesian Coal Basin". Gospodarka Surowcami Mineralnymi 32, nr 1 (1.03.2016): 5–24. http://dx.doi.org/10.1515/gospo-2016-0009.
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Abstract The article presents the results of tests of porosity of the Upper-Silesian Coal Basin (USCB) hard coals. The porosity was determined for various lithotypes of hard coal, collected in different areas of the Upper-Silesian Coal Basin. Samples of hard coal were collected in 60 seams of 16 coal mines, from the depth of approximately between 350 and 1200 m. There are also presented differences in values of open porosity of coal depending on the depth of occurrence, as well as chronostratigraphic and tectonic correlation of a seam. Uniaxial compression strength of the tested coals falls in the strength class from very low to very high (from 8.1 to 51.5 MPa), open porosity is 0.68–12.5% and total porosity is 3.29–17.45%. With an increase in depth, in general, open porosity of coals decreases. There is an apparent decrease in open porosity correlated with the age of hard coals. It was observed that the lower and upper limits of open porosity ranges of variability shift towards lower values the older the coals are, from the Łaziskie Beds to the Jaklowieckie Beds. The older the coals the greater the average drop in the share of open porosity in total porosity from 60% for the youngest coals to merely several per cent for the oldest ones. The highest values of total porosity (over 10%) were observed in the youngest coals (Cracow sandstone series and siltstone series). Older coals reached more diversified values of total porosity (3.29–17.45%). Based on the conducted tests, zones correlated with tectonics of the basin and with deposition of lithostratigraphic beds of specific age, where values of porosity of hard coals differ, were determined in the area of the USCB. However, in spite of their correlation to a structural unit, the coals demonstrated a decrease in open porosity with an increase in their geologic age. Thus, there is an apparent influence of the deposition depth of coal within a given structural unit on open porosity following the age of coal, i.e. correlation to an older and older chronostratigraphic unit. Porosity tests of hard coal are published in scientific journals yet, most often, there is no information on the type of porosity. Such detailed characteristics of open porosity for coal of the Upper Silesian Coal Basin, as in the article, have not been prepared yet, making our research novel. Such broad tests of porosity of hard coals, correlated with their strength and referring to the deposition depth of seams as well as a correlation to lithostratigraphic units within individual structural units in the USCB, had not been conducted yet. We believe it is a sufficient argument to start detailed research into the open porosity of hard coals. The results of the tests are important from both the research and practical points of view. Knowledge of coal porosity is indispensable in solving many engineering problems of geological engineering, mining geomechanics and mining e.g.: assessing behaviour of coal when it is mined and processed, assessing the possibility of capturing methane, which makes up over 90% of natural gas, from coal in the areas of methane-rich deposits; the possibility of storing various substances in abandoned hard coal mining areas (e.g. CO2 storage within the structure of coal), assessing risk of occurrence of certain natural hazards resulting from mining deposits (e.g. coal and rocks outburst hazard), as well as assessing the possibility of applying unconventional methods of mining hard coal deposits (e.g. underground coal gasification).
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Wang, Guang Heng, i An Ning Zhou. "Effect of Coal Structure on Mechanical and Thermal Properties of Coal Filled Soy Protein Composites". Advanced Materials Research 236-238 (maj 2011): 288–91. http://dx.doi.org/10.4028/www.scientific.net/amr.236-238.288.
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Using different rank coals as filler, coal-soy protein isolate (SPI) composites were prepared by compression molding processing using glycerol as plasticizer. The structure of the coals used were characterized by Fourier transform infrared (FTIR), ultimate analysis, and surface functional group analysis. The effects of coal structure on the mechanical properties, water resistance, and thermal properties were investigated. The results showed that, in different rank coals, the atomic ratio of oxygen to carbon, carboxylic acid groups, phenolic hydroxyl groups, lactone bonds, and aliphatic chains decreased with coal rank. The strength, water resistance, and glass transition temperature of coal-SPI composites decreased with coal rank. Lower ran coal filler with more reactive functional groups caused the composites strong but brittle. While, higher rank coals provide poor mechanical properties for the composites.
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Liu, Yang, i Di Wu. "The Research of Variation Regularity of Coal Bed Methane Production in CO2 Flooding". Advanced Materials Research 868 (grudzień 2013): 677–81. http://dx.doi.org/10.4028/www.scientific.net/amr.868.677.
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CO2flooding can increase coal bed methane production rate, enhance coal bed methane recovery and store CO2into underground. It has good application prospect for CBM development. This paper analyzes the adsorption-desorption law of mixed gas in the coal during the CO2injection process, as well as the diffusion and seepage law of gas in the coal seam. The sensitivity of factors affecting coal bed methane production is studied and then the coal bed methane production under different conditions is simulated numerically. The results show that methane concentration and coals permeability are the two key factors affecting the output of coal bed gas and their influence on productivity are even more significant than injection pressure and initial pressure. The higher injection pressure, coals permeability and gas concentration, the greater amount of methane the coal reservoirs will yield. When the coals permeability and the gas concentration in coal reservoirs increase, the growth rate of methane production accelerates accordingly.
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Umar, Datin, Suganal Suganal, Ika Monika, Gandhi Hudaya i Dahlia Diniyati. "The influence of steam drying process on combustion behavior of Indonesian low-rank coals". Indonesian Mining Journal 23, nr 2 (listopad 2020): 105–15. http://dx.doi.org/10.30556/imj.vol23.no2.2020.1105.
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Steam drying process of the Low Rank Coals (LRCs) has been conducted to produce coal which is comparable with the High Rank Coal (HRC). Characterization of the raw and dried coals was carried out through proximate, ultimate, calorific value, Fourier Transform Infrared (FTIR) spectroscopy and Thermo Gravimetry-Differential Thermal Analysis (TG-DTA) to study the combustion behavior of the coals. This study used Indonesian low rank coals coming from Tabang (TKK coal) and Samurangau (SP coal), East Kalimantan. The results indicate that the calorific value of the dried coals increases significantly due to the decrease in moisture content of the coal. The FTIR spectrums show that the methylene-ethylene (RCH3/CH2) and aromaticity-aliphaticity ratios (Rar/al) of the dried coals increased while the ratio of RCO/ar decreased which reflect that the rank of the coals increased equivalent to the high rank coal (bituminous). Meanwhile, the TG-DTA indicates that the ignition temperature (Tig) and combustion rate (Rmax) of the dried coals increased. This analysis expresses that the dried coals produced by steam drying process have better combustion behavior due to the higher calorific value than those of the raw coals.
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Li, Han Xu, Xiang Cao i Yong Xin Tang. "Study of Effect of Ternary-Component Blended Coal on Coal Gasification Reaction at High Temperature". Applied Mechanics and Materials 295-298 (luty 2013): 3104–9. http://dx.doi.org/10.4028/www.scientific.net/amm.295-298.3104.
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Three typical Chinese individual coals which existed remarkable difference on coal ash chemical composition and ash fusion temperature were selected to carry out coal blending experiments to study the coal gasification reaction at high temperature by means of using ternary-component blended coal technique and TGA-DTA method. According to ternary-component blended coal with a certain proportion, ash chemical composition and coal-char/CO2 gasification reactivity were analyzed by X-ray fluorescence (XRF) and thermogravimetric analysis-derivative thermogravimetric analysis (TGA-DTG), respectively. The results show that the ash chemical components change because ternary-component blended coals change the mineral composition, and hence, the gasification reactivity can be affected as well. Moreover, in accordance with reactivity index R, it indicates that the order of gasification reactivity of three individual coals and four blended coal options is coal x > option B > option A > option D > option C > coal z >coal y. Meanwhile, a new mathematical model called per unit ash alkali index B* was established by using the ash chemical component dates, which has a good corresponding relationship with R for four blending coal options. Utilizing ternary-component blended coal technique could improve the high-temperature coal ash gasification reaction.
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Wierzchowski, Krzysztof, Jarosław Chećko i Ireneusz Pyka. "Variability of Mercury Content in Coal Matter From Coal Seams of The Upper Silesia Coal Basin". Archives of Mining Sciences 62, nr 4 (20.12.2017): 843–56. http://dx.doi.org/10.1515/amsc-2017-0058.
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Abstract The process of identifying and documenting the quality parameters of coal, as well as the conditions of coal deposition in the seam, is multi-stage and extremely expensive. The taking and analyzing of seam samples is the method of assessment of the quality and quantity parameters of coals in deep mines. Depending on the method of sampling, it offers quite precise assessment of the quality parameters of potential commercial coals. The main kind of seam samples under consideration are so-called “documentary seam samples”, which exclude dirt bands and other seam contaminants. Mercury content in coal matter from the currently accessible and exploited coal seams of the Upper Silesian Coal Basin (USCB) was assessed. It was noted that the mercury content in coal seams decreases with the age of the seam and, to a lesser extent, seam deposition depth. Maps of the variation of mercury content in selected lithostratigraphic units (layers) of the Upper Silesian Coal Basin have been created.
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Yang, Xi Yuan, Mei Li Du, Jin Ren Zhang i Jian Li Yang. "Study on Coal Separability for Wangcun Inclined Shaft in Chenghe". Advanced Materials Research 734-737 (sierpień 2013): 1082–85. http://dx.doi.org/10.4028/www.scientific.net/amr.734-737.1082.
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On the basis of the coal quality characteristics, the screening and drifting tests have been carried out to investigate the separability of the coals in the inclined shaft coal samples of Chenghe Wangcun coal mine. The results showed that the mine raw coal seams are medium ash, high sulfur and medium volatile coals. The screening test results showed that the water content and sulfur content of coals samples in each grade after sieving essentially remained the row coal characteristic. Heating value increased with the decrease of particle size, but ash content decreased with the particle size. The float-and-sink tests showed that when the given clean coal ash content was 10%13% and 15% respectively, the coal samples were in the extremely difficult degree, medium separability degree and medium separability degree respectively.
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Bielowicz, Barbara, i Jacek Misiak. "The Impact of Coal’s Petrographic Composition on Its Suitability for the Gasification Process: The Example of Polish Deposits". Resources 9, nr 9 (9.09.2020): 111. http://dx.doi.org/10.3390/resources9090111.
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In this paper, we discuss the impact of the rank of coal, petrographic composition, and physico-chemical coal properties on the release and composition of syngas during coal gasification in a CO2 atmosphere. This study used humic coals (parabituminous to anthracite) and lithotypes (bright coal and dull coal). Gasification was performed at temperatures between 600 and 1100 °C. It was found that the gas release depends on the temperature and rank of coal, and the reactivity increases with the increasing rank of coal. It was shown that the coal lithotype does not affect the gas composition or the process. Until 900 °C, the most intense processes were observed for higher rank coals. Above 1000 °C, the most reactive coals had a vitrinite reflectance of 0.5–0.6%. It was confirmed that the gasification of low-rank coal should be performed at temperatures above 1000 °C, and the reactivity of coal depends on the petrographic composition and physico-chemical features. It was shown that inertinite has a negative impact on the H2 content; at 950 °C, the increase in H2 depends on the rank of coal and vitrinite content. The physicochemical properties of coal rely on the content of maceral groups and the rank of coal. An improved understanding these relationships will allow the optimal selection of coal for gasification.
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Dziok, Tadeusz, i Andrzej Strugała. "Preliminary assessment of the possibility of mercury removal from hard coal with the use of air concentrating tables". Gospodarka Surowcami Mineralnymi 33, nr 4 (20.12.2017): 125–41. http://dx.doi.org/10.1515/gospo-2017-0043.
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Abstract Mercury is characterized by highly toxic properties. The natural biogeochemical cycle of mercury occurs in the environment, which results in the fact that even a small amount of mercury emitted to the environment is a potential threat to human health. The process of coal combustion is one of the main sources of anthropogenic mercury emissions. For this reason, on 31 July 2017 the European Commission has adopted the mercury emission standards for large combustion plants. The issue of mercury emissions is particularly important for Poland. Forecasts concerning energy consumption in Poland show that coal will be the main source for energy production in the coming decades. Therefore, actions enabling the reduction of mercury emissions from coal-fired power plants will have to be implemented. The mercury emissions from coal-fired power plants may be reduced through the application of a number of methods. These methods can be divided into two main groups: the post-combustion methods which allow for mercury removal from flue gases, and the pre-combustion methods which allow for mercury removal from coal before its combustion. The effectiveness of mercury removal from coal is determined by the mode of its occurrence in coal. In the case of mercury occurrence in the adventitious inorganic constituents of coal, high effectiveness will be obtained in the coal cleaning processes. In the case of mercury occurrence in the organic matter as well as in the inherent inorganic constituents of coal, the effectiveness of this method will be low. Mercury could be removed from such coals through the process of thermal pretreatment at the temperature of 200-400°C (mild pyrolysis). In the paper, the possibility of mercury removal from hard coal through the process of dry deshaling on an air concentrating table was examined. Six raw coals (coal feed), clean coals and the rejects derived from their dry deshaling were analyzed. The mercury content was measured in the examined samples. The content of mercury in raw coals and clean coals were compared. Additionally, the effectiveness of mercury removal from coal with rejects was determined. For the analyzed coals, the effectiveness of mercury removal from coal in the process of dry deshaling on an air concentrating table ranged from 9 to 96%. This effectiveness is similar to the effectiveness of mercury removal from coal in the processes of coal washing. It should be mentioned that, when compared to the coal washing processes, the dry deshaling process is characterized by lower investment and operating costs. Therefore, the dry deshaling process on an air concentrating table should be considered as a competitive method for the coal washing processes. There is also a possibility of an increase in the mercury removal efficiency from coal in the process of dry deshaling as a result of the thermal pretreatment of clean coal derived from dry deshaling. This solution is only recommended for coals in which mercury occurs in the organic matter as well as in the inorganic constituents characterized by a relatively low temperature of mercury release.It should be emphasized that the dry deshaling process allowed for a decrease of mercury content is not suitable for every coal. Although for five of the analyzed coals the mercury content in clean coal was lower in the range from 11 to 53%, for one coal the mercury content was higher by 19%. The effect of decreasing the mercury content in coal is more evident when it is related to the amount of energy contained in coal (i.e. for example to the lower heating value). For five of the analyzed coals mercury content expressed in such a way decreased in the range from 11 to 53 %, and for one coal the mercury content was, however, higher. Nevertheless, the difference was not very significant (ca. 5%).
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Chandaliya, Vimal Kumar, Saibal Trivedy, Avinash Tiwary, Asaithambi Suresh, Pratik Swarup Dash i Abanti Sahoo. "Utilization of steel plant waste and by-products in reactive coke making". Metallurgical Research & Technology 120, nr 1 (2023): 103. http://dx.doi.org/10.1051/metal/2022109.
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Coke is used in the blast furnace as a fuel. To produce the coke, metallurgical coals are blended in the coal blend. But the reserves of the coking coals are limited in India. Hence, there is a need to use the non-coking coals in the blast furnace. However, there is a limitation for use of non-coking coals in the coal blend for coke making. So, an attempt was made in this study to increase the amount of non-coking coals in the coal blends. In the present work, briquetting technique was used for producing briquettes having non-coking coal up to 40%, and rest is slightly coking coal along with reactive materials and binders. Those samples were compressed in a hydraulic press to form briquettes which were then carbonized. The strength and reactivity tests of those coal briquettes were carried out to determine the optimum addition proportion of reactive materials and binders. It was found that 10% of reactive material was optimum for briquette making. The use of coal tar pitch and petroleum pitch binders were also studied, and their optimum values were obtained as 3%. It was also found that coal briquettes comprising of LD (Linz-Donawitz) slag and iron oxide exhibited higher reactivity as compared to other reactive materials.
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Ren, Xiao Yuan, Zhi Yuan Yang, Shi Cun Qu i Jiang Long. "The Effect of Sodium Dodecyl Sulphate (SDS) on Wettability of Different Coals". Advanced Materials Research 734-737 (sierpień 2013): 513–16. http://dx.doi.org/10.4028/www.scientific.net/amr.734-737.513.
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Three coals (Jincheng coal, Hancheng coal and Shan-bei coal) varying widely in coal type have been treated with anionic surfactant Sodium Dodecyl Sulphate (SDS). The effect of SDS on wettability of coals was explored by contact angles and zeta potentials characterisation techniques. Results obtained show that the addition of SDS can obviously improve the wettability of coals, and as the coal rank decreases, the wettability increases under investigation. Moreover, the wettability obviously increases with the significant decrease of particle size. The zeta potential for each coal, in the absence of surfactant, is negative, and the potential becomes more negative with the addition of SDS. Meanwhile, the FTIR spectrogram was used to test the changes of-COOH and-OH to analyze the reason for change of wettability, the results show that the wettability changes may be attributed to that the negative active ions of SDS are adsorbed on the coal surface, resulting in the increase of hydrophilic groups of the coal surface.
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Wang, Linlin, i Zhengjiang Long. "Evolutions of CO2 Adsorption and Nanopore Development Characteristics during Coal Structure Deformation". Applied Sciences 10, nr 14 (21.07.2020): 4997. http://dx.doi.org/10.3390/app10144997.
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The coal structure deformation attributed to actions of tectonic stresses can change characteristics of nanopore structure of coals, affecting their CO2 adsorption. Three tectonically deformed coals and one undeformed coal were chosen as the research objects. The isotherm adsorption experiments of four coal specimens were carried out at the temperature of 35 °C and the pressure of 0 to 7 MPa. Nanopore structures were characterized using the liquid nitrogen adsorption method. The results show that there exist maximum values of excess and absolute adsorption capacity, which increase with increasing coal deformation degree. As the degree of coal deformation increases, the pore volume and specific surface area present an obvious increasing trend in the case of micropores, exhibiting an increase at first (cataclastic coal and ganulitic coal) and then stabilization (crumple coal), in the case of mesopores, and showing a gradual decrease in the case of macropores. The mesopores are the key factor of CO2 adsorption of tectonically deformed coals, followed by the micropores and the limited effect of macropores at the strong coal deformation stage.
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So, Min Seop, Duncan Kibet, Tae Kyeong Woo, Seong-Joon Kim i Jong-Ho Shin. "Prediction of SOx-NOx Emission in Coal-Fired Power Plant Using Deep Neural Network". Machines 11, nr 12 (23.11.2023): 1042. http://dx.doi.org/10.3390/machines11121042.
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Coal has been used as the most commonly energy source for power plants since it is relatively cheap and readily available. Thanks to these benefits, many countries operate coal-fired power plants. However, the combustion of coal in the coal-fired power plant emits pollutants such as sulfur oxides (SOx) and nitrogen oxides (NOx) which are suspected to cause damage to the environment and also be harmful to humans. For this reason, most countries have been strengthening regulations on coal-consuming industries. Therefore, the coal-fired power plant should also follow these regulations. This study focuses on the prediction of harmful emissions when the coal is mixed with high-quality and low-quality coals during combustion in the coal-fired power plant. The emission of SOx and NOx is affected by the mixture ratio between high-quality and low-quality coals so it is very important to decide on the mixture ratio of coals. To decide the coal mixture, it is a prerequisite to predict the amount of SOx and NOx emission during combustion. To do this, this paper develops a deep neural network (DNN) model which can predict SOx and NOx emissions associated with coal properties when coals are mixed. The field data from a coal-fired power plant is used to train the model and it gives mean absolute percentage error (MAPE) of 7.1% and 5.68% for SOx and NOx prediction, respectively.
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Maussymbayeva, A. D., V. M. Yurov, V. S. Portnov, M. Rabatuly i G. M. Rakhimova. "Assessment of the influence of the surface layer of coals on gas-dynamic phenomena in the coal seam". Naukovyi Visnyk Natsionalnoho Hirnychoho Universytetu, nr 2 (30.04.2024): 5–11. http://dx.doi.org/10.33271/nvngu/2024-2/005.
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Purpose. Development of physical and mathematical model linking nanostructured surface layer of coal substance with geodynamic phenomena of coal seam, through adhesion energy of different layers and coal grades, melting temperature of the nanolayer, determination of the role of stress-strain state of the seam in the formation of fine coal and methane at their emissions into the mine workings. Methodology. Mathematical and experimental studies of the regular change in the surface layer of coal substance depending on the grade of coals for different formations of the Karaganda basin; assessment of the influence of the surface layer of coal on the adhesion energy, which determines the stress-strain state of the coal seam. Physical methods for studying the decomposition temperature of methane-bearing coal seams, changes in its concentration, reaction rate of methane release from coals. Findings. A regular decrease in the thickness of the surface nanolayer of coal substance in different coal grades and formations in the metamorphic series of coals is shown. It has been found that this decrease is accompanied by an increase in surface energy and adhesion energy. The connection of gas-dynamic phenomena with stress-strain state of coal seam, which forms fine-dispersed structure of coal, forms of methane location, activation energy of solid coal-methane solution, rate of thermal decomposition reaction, critical stresses determining development of cracks in coal substance is shown. Originality. For the first time, a physical model for calculating the thickness of the surface nanolayer and its surface energy for coals of different grades of the Karaganda basin has been developed; the relationship between the thickness of the nanolayer and the melting temperature, adhesion energy, linking the stress-strain state of the coal bed in the zone of gas-dynamic phenomena and the concentration of methane has been established. The value of internal stresses in the surface layer of coals of different grades has been found to be a constant value. Connection of activation energy of decomposition of solid coal-methane solution from Gibbs energy and methane concentration, which explains its significant amount in gas-dynamic phenomena, has been established. Practical value. The physical and mathematical model describes the influence of surface coal on the processes occurring in the zone of gas-dynamic phenomena and the regularities of their changes depending on the thickness of the surface nanolayer determining such parameters as: stress-strain state, dispersion of coals, as well as the release of a large amount of methane at the sudden release of coal gas into the mine workings.
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Hong, Lin, Wenjing Wang, Dameng Gao i Wentong Liu. "Critical pore size for micropore filling in coal samples with different rank coals". PLOS ONE 17, nr 3 (11.03.2022): e0264225. http://dx.doi.org/10.1371/journal.pone.0264225.
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The objectives of this study were to explore the occurrence and migration of coalbed methane in coals of different ranks and reveal the microscopic reservoir space and the mechanism of coalbed methane. To meet these objectives, this study selected six coal samples of different coal ranks for low-pressure N2 adsorption experiments, explored the critical pore filling characteristics of packed N2 molecules in the coals, and analyzed the low-pressure N2 adsorption/desorption experimental isotherms using the DFT method and DA equation based on the micropore filling theory. Finally, the critical filling pressure and pore size range for micropore filling were determined, and the analysis results were verified by combining the Langmuir, DA, and BET equations. The results showed that, from low to high coal rank, the N2 adsorption/desorption isotherms of the coal samples transition from type Ⅱ to type Ⅰ. The proportion of N2 molecules in low-rank coals in the form of micropore filling and monolayer adsorption was higher than that in high-rank coals. The critical pressure and critical pore size for micropore filling exhibited U-shaped correlations with the coal rank. Low-rank coals (lignite and long flame coal) were gradually filled in the relative pressure range P/P0 ≈ 1E-4–0.03, and medium- and high-rank coals (gas coal, 1/3 coking coal, lean coal, and anthracite) were filled in the relative pressure range P/P0 ≈ 1E-4–0.01; the corresponding critical pore size ranges were 1.7–2.19 and 1.61–2.00 nm, respectively.
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Liu, Jian Zhong, Yu Jie Yu, Jun Hu Zhou, Chong Du, Lin Ye, Jun Cheng i Ke Fa Cen. "Study on the Effects of Coal Blending on the Slurry Ability of Shenmu Coals". Advanced Materials Research 383-390 (listopad 2011): 3011–16. http://dx.doi.org/10.4028/www.scientific.net/amr.383-390.3011.
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Shenmu coals as low rank coal are difficult to prepare for Coal Water Slurry (CWS). The maximum slurry concentration of Shenmu CWS is lower than 60%, which is not available for practical application. Coal blending is a simple operation and low cost method to improve the slurry ability of low rank coal. Two different kinds of anthracite and bituminous coal samples were blended in Shenmu coal to study the effect on the preparation of CWS, respectively. The results showed that the maximum solid concentration of CWS increased as the proportion of high rank coal rise. And the viscosity of CWS is dropped at the same concentration. Different coals blending have different effects on the elevation of slurry ability for Shenmu coal. The raw coal with best slurry ability is not always the most suitable for blending in low rank coal. HuanNan bituminous coal is the best choice for blending in Shenmu coal. The maximum solid concentration of CWS can be increased by 6% when the proportion of HuanNan coal reached to 70%.
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Qi, Ling Ling, Zhao Feng Wang i Hong Min Yang. "Research on the Differences of the Pore Characteristics with Different Destroyed-Type Coals". Advanced Materials Research 619 (grudzień 2012): 598–602. http://dx.doi.org/10.4028/www.scientific.net/amr.619.598.
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In order to investigate the pore characteristics of the different destroyed-types of coals and its effects of coal and gas outburst, this article studyed the low temperature nitrogen adsorption curve, specific surface area, pore volume and its distribution with the method of low-temperature nitrogen adsorption, also studed their changes with the different destroyed-type of coals, and the influences of pore shape and distribution for coal and gas outburst. The results showed that three different destroyed-types of coals have loops, the pore shapes of the coals mainly open-shaped, maybe also contain the flask-shaped. The raw coal has more open-shaped pores, fragmentated coal contains a large number of micropore, the crushed coal richs micropore and mesopore. The crushed coal in the large aperture of the medium relative pressure range mainly has open-shaped pore, then in maller pore size range of low relative pressure mainly has closed pore. With the increasing of destroyed-degree, the porosity increased, the anti-destruction capability reduced, the coal is more easily broken, then the risk of outburst is greater.
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Mohd Samsuri, Muhamad Shazarizul Haziq, Hasril Hasini, Noor Akma Watie Mohd Noor i Meor Mohd Faisal Meor Zulkifli. "Temperature Profile Assessment of Sub-Bituminous Coal by Using a Single Burner Combustion Test Facility". Journal of Advanced Research in Fluid Mechanics and Thermal Sciences 78, nr 1 (1.12.2020): 1–10. http://dx.doi.org/10.37934/arfmts.78.1.110.
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This paper presents a thermogravimetric analysis and combustion test for different coals used in a coal-fired power plant in Malaysia. The main objective is to investigate the suitability of adopting a newly-introduced sub-bituminuous coal in an existing boiler furnace commonly firing standard design coals. In order to ensure that the new coal will not give an adverse effect to the boiler, detail analytical and thermal performance of the new coal is investigated, together with design and other limiting coals. The combustion test was performed in a scaled down, 150kW, single swirl burner combustion test facility available in TNB Research Sdn. Bhd. In the study, combustion gas temperature at different sectors downstream of burner region is measured to determine the peak temperature for all tested coals. Based on the investigation, it was noted that coal with the highest fixed carbon content gives the highest temperature measure at all sectors. Similarly, coal with the lowest fixed carbon gives the lowest temperature. The temperature profile for the newly tested coal was found to be comparable to the design and limiting value coals. Even though it was observed that the temperature given by the new coal is the highest slightly downstream of the burner, the temperature was observed to be decreases as combustion gas flow downstream of the combustor rig. Based on the observation it can be said that the new coal is suitable to be used by the existing boiler furnace.
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Wang, Yong Zheng, Xiu Juan Li, Su Le Tian i Chun Mei Lu. "Experimental Study on the Pollutants Release Characteristics During Combustion of Lean Coal with Different Coal Rank". Advanced Materials Research 518-523 (maj 2012): 2143–46. http://dx.doi.org/10.4028/www.scientific.net/amr.518-523.2143.
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In this paper, the characteristics of SO2 and NO release during combustion of lean coal with different coal rank were experimentally studied in the one-dimensional furnace for pulverized coal combustion. The results showed: The coal property and proportion of the component coals have great influence on the characteristics of SO2 and NO release. The releasing concentration of SO2 and NO distributing along the furnace height is generally between that of component coals, and the releasing characteristics of SO2 and NO would be more near to that of the larger proportion coal. The measuring value of the formation concentration of SO2 and NO are different from the calculating value based on the weighted means of the component coals to a certain extent. While the different coal are added to lean coal, the time corresponding with peak value releasing concentration of SO2 and NO is different.
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Teng, Juan, Yan Bin Yao, Da Meng Liu, Zhi Qiang Liu i Bei Liu. "Identification of Coal Petrologic-Structure by Using Geophysical Logging Data: A Case Study of the Coals of Hancheng Coalbed Methane Field". Applied Mechanics and Materials 316-317 (kwiecień 2013): 795–98. http://dx.doi.org/10.4028/www.scientific.net/amm.316-317.795.
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Coal petrologic structure is important for the prediction of coal and the associated coalbed methane outburst during coal mining. This paper discusses the relationship between the response characteristics of natural gamma (GR), laterlog deep (LLD) and compensation density curve (RHOB), and the coal structures. Results show that the tectonic-coals (the coals with high breakage degree by tectonic structures) can be identified by the logging characteristics of low amplitude of GR (20-90 API), high amplitude of LLD (300-1800 Ωm), and low amplitude of RHOB (1.25-1.5g/cm3). It was found that with increasing degree of the breakage, coal pores and fractures become well developed, and thus reduce the bulk density of coal and the content of radioelement but more gas within the coal. This is the reason for logging performances of low amplitude of GR and RHOB, as well as high amplitude of LLD for the tectonic-coals.
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Kopobayeva, A. N., I. V. Baydauletova, A. Amangeldikyzy, N. S. Askarova i G. G. Blyalova. "Nature of ree accumulation in clayey interlayers and coals in Karaganda coal basin". Kompleksnoe Ispolzovanie Mineralnogo Syra = Complex Use of Mineral Resources 332, nr 1 (3.05.2024): 49–61. http://dx.doi.org/10.31643/2025/6445.04.
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It is the first completed complex mineralogical and geological research of REE (Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu) in the coals of Karaganda coal basin in Central Kazakhstan. This paper presents the results of the research of REE (from lanthanum to lutetium and Y) distribution in 85 samples of coal and clayey interlayers of stratum k7 of Karaganda coal basin in the faces of Saranskaya, T.Kuzembayev, Aktasskaya mines. The ultimate composition of clayey interlayer and coal samples was analyzed by the methods of inductively coupled plasma optical emission spectroscopy and inductively coupled plasma mass spectrometry (ICP-OES and ICP-MS). Research of the lateral and vertical discontinuity of the total REE concentration has indicated the presence of mixed types of REE distribution in coals, which supposes various forms of REE migration and different mobility of heavy and light lanthanides within the hypergenesis zone. The established lanthanum-ytterbium (La/Yb) ratio in the coal, which is normalized to UCC and equals La/Yb<1, relates to the coals with Н type of REE distribution, and the one that equals La/Yb>1 and normalized to chondrite belongs to the coals with L type of REE distribution, which allows making conclusions on the presence of independent sources and different mechanisms of REE accumulation in the sediments of Karaganda coal basin. It is also established that the La/Yb ratio grows from coals to clayey interlayers, which indicates a predominantly clastogenic mechanism of REE input to the coals. The prevailing mineral form of the REE in the coal and clayey interlayer samples from the Karaganda coal basin is light lanthanide phosphates. Sparry crystals with CeLaNdPO composition were found in the coal and clayey interlayer samples. It was established that xenotime is the main deportment for Y in many coals.
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Fang, Jiuwen, Mingxin Li, Baosheng Gao, Yuqin Zeng, Lingcan Zhang, Jiawei Qiao, Xinshi Jie i Xianbin Xiao. "Numerical simulation of pulverized coal combustion in a 660MW tangentially fired boiler with fuel variation". Journal of Physics: Conference Series 2599, nr 1 (1.09.2023): 012022. http://dx.doi.org/10.1088/1742-6596/2599/1/012022.
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Abstract To study the effects of various coal properties on the combustion characteristics during actual operation, and on the high temperature corrosion of the water wall. The paper presents a numerical simulation of a 660MW boiler using ANSYS FLUENT software. Three cases were investigated with various fuel properties: (1) the designed coal NO.1, (2) the non-designed coal NO.2 with high ash, high sulphur content and low volatile matter, (3) the blended fuel of coal NO.3with similar coal quality to the coal NO.1 and NO.4 with high sulphur content. Simulation results indicate that blended coal feeding can improve the combustion characteristics of poor-quality coals. It provides a theoretical reference for the actual operation of power plants with non-designed coals.
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Antoshchenko, М. I., V. Yu Tarasov, О. I. Zakharova i Ye I. Zubtsov. "Research of vitrinite and fusinite coals for predicting geological hazards in coal seams". Мінеральні ресурси України, nr 3 (12.11.2020): 45–49. http://dx.doi.org/10.31996/mru.2020.3.45-49.
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To establish the necessity of dividing fossil coals into vitrinitic and fusinitic varieties in order to identify the hazardous properties of coal seams during mining.
Methodology. The study of changes in conditional indices in the general ranking series was carried out according to DSTU 25543-2013 separately for the classification indicators of vitrinite and fusinite coals, as well as coal groups not assigned to the considered varieties. Changes in indices in the ranks of classification indicators allow us to identify the distinctive or unifying features of the construction of these series and provide suggestions for improving the regulatory documents of mining operations.
Outcome. The safety of mining in Ukrainian coal mines is regulated by a number of regulatory documents that are based on genetic classification indicators of coal. One of the decisive factors of dividing coals by technological properties is their classification as vitrinitic or fusinitic, which is not taken into account by the regulatory framework when establishing the hazardous properties of coal seams.
The analysis of distinctive properties acquired in the process of metamorphic transformations between vitrinite and fusinite coals has been carried out. It is established that the correlation indices (R2) of the relationship between conditional indexes of Ro, Vdaf and у ranking series with the conditional indices of the general ranking series by brand of coal are practically the same. In terms of Ro, the values of R2 for vitrinitic and fusinite coals were 0,9114 and 0,9221, respectively. Similar results were obtained for the Vdaf indicator, according to which it is impossible to establish differences in the degree of metamorphic transformations between vitrinite and fusinite coals. The characterizing values of the у indicator do not make it possible to establish the direction of change in the properties of coal. The used values of this indicator have a large scatter in the compilation of coal ranking.
Scientific novelty. The nature of change in the classification indicators of industrial classification of coal for identifying the hazardous properties of coal seams in mining operations has been identified.
Practical relevance. The possibility of improving the regulatory framework for safe mining of coal seams by establishing differences in the properties of vitrinite and fusinite coals.
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Gong, Shuang, Zhen Wang, Lei Zhou i Wen Wang. "Influence of Cyclic Impact Loading and Axial Stress on Dynamic Mechanical Properties of Burst-Prone Coal". Shock and Vibration 2021 (13.01.2021): 1–10. http://dx.doi.org/10.1155/2021/6649308.
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High in-situ stress and frequent dynamic disturbances caused by the mining process in deep coal mines can easily induce dynamic disasters such as coal burst. We conducted laboratory experiments to assess the effects of the axial stress loading and dynamic cyclic impact loading on the dynamic mechanical properties of burst-prone coals by using a modified split Hopkinson pressure bar (SHPB). Comparisons were made using two types of burst-prone and burst-resistant coal samples. The mineral components, organic macerals, and dynamic mechanical features of both burst-prone and burst-resistant coal samples were comparatively analyzed based on the obtained X-ray diffraction (XRD), optical microscope observations, and dynamic compressive stress-strain curves, respectively. The results of the microstructure analysis indicated a larger difference between the minimum and maximum reflectances of vitrinite for burst-prone coal. Compared to the burst-resistant coal samples, the burst-prone coals contained less corpocollinite and fusinite. While applying a high axial static load combined with cyclic impact load, the coal samples showed the characteristics of fatigue damage. The results also demonstrated that preaxial stress affected the burst resistance of coal samples. The greater the preaxial stress was, the less the coal samples could withstand the dynamic cyclic impact load. In comparison to the burst-resistant coal sample, the burst-prone coal sample showed a larger dynamic compressive strength and a lower deformation. They were also more positively capable of the propagation and activation of the coal burst. We believe that the results of the study are conducive to further understanding of the distribution of microcomponents of burst-prone coals. The results are also beneficial for realizing the dynamic mechanical characteristics of burst-prone coals under the impact of cyclic dynamic load.
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Tarasov, Vadym, Mykola Antoshchenko, Olha Zakharova, Anastasiia Zakharova i Oleg Levadnyi. "Moisture as assessment criterion for coal rank and coal layers hazardous characteristics manifestation". E3S Web of Conferences 280 (2021): 08019. http://dx.doi.org/10.1051/e3sconf/202128008019.
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For the time being, moisture effect to the useful quality of coals has been researched comprehensively in detail. Herewith, there are a lot of unsolved problems related to the safety working out of coal layers. Presence of different forms of moisture in fossil coals essentially influences the coal layers hazardous characteristics manifestation during the mining activities. The Article deals with the results of analyses of more than thousand samples of the Donets Basin coals from different deposits, to research the relationship of total moisture and organic matter components in the coal carbonizations during the metamorphic processes. The researches have allowed separation of 3 stages for the fossil coal conversions. It is noted that at the initial stage, the carbon content is about 80%, moisture proportion in carbonization is rather high—0.36; but it decreases abruptly down to 0.12, in case of the carbon content increasing up to 86.5%. And the proportion of components (hydrogen, oxygen, nitrogen, and sulphur) total increases essentially up to 0.88. At the next stage, at 86.5÷91.5%, the components proportion in carbonization changes insignificantly. At the final stage of coal metamorphic conversions, 4-time growth of moisture proportion takes place in carbonization. It is found that moisture proportion in any form to be found in the coals shall be considered as a rank index, which is necessary to determine the coal layers hazardous characteristics.
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Hartiniati, Hartiniati. "UJI PENINGKATAN MUTU BATUBARA PERINGKAT RENDAH SUMATERA SELATAN". Jurnal Energi dan Lingkungan (Enerlink) 7, nr 1 (15.06.2011): 9. http://dx.doi.org/10.29122/elk.v7i1.2729.
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A study of coal upgrading by way of evaporative method using coal from SouthSumatra is conducted. Preliminary inestigation on Upgrading of Brown Coal(UBC) process using Central and South Banko coals suggests that the processcan be applied to both coals (called S-BK and C-BK) without any operationalproblem. It produces high quality-stable coals in the briquette form with a calorificvalue of more than 6,500kcal/kg. Moreover, its spontaneous combustioncharacteristic is also suppressed comparing to that conventional drying method.This is due to the addition of aspal (heavy oil) in the solution of kerosene, wherethe aspal then soaked in the micropore of to prevent reabsorption of water whenput in the air.Kata Kunci: upgrading brown coal, Banko coal, briket batubara, spontaneouscombustion
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Baskoro, Ardian Nugra, Farhan Hadi Taskaya, Ignatio Senoaji Jagad Mitro Prajasto i Robby Anggoro. "Heat Quality Enhancement and Carbon Dioxide Emissions Reduction from Coal Burning by Combining Low-Ranked Coal with Biomass Waste as A Clean Energy Solution to Achieve Energy Security in Indonesia". Indonesian Journal of Energy 4, nr 2 (31.08.2021): 115–28. http://dx.doi.org/10.33116/ije.v4i2.120.
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Indonesia is the fifth largest coal producer in the world with coal reserves reaching 39.56 billion tonnes. Coal reserves of medium and high quality are expected to be exhausted in 2048, therefore it is necessary to utilize low-ranked coals. Low-ranked coals have a low heating value (<5,100 kcal/kg) and produce greater CO2 emissions compared to medium and high rank coals. One method to increase heating value and reduce CO2 emissions from low-ranked coals is through the Utilization of hybrid coal. Hybrid coal is low quality coal combined with biomass waste and has undergone a pyrolysis process together. The mixing and co-pyrolysis of low-ranked coal with biomass waste such as rice husk, empty palm fruit bunches, and rubber wood with a ratio of 7:3 is known to be able to increase the final product calorific value by 31.10–44.12% and reduce non-neutral CO2 emissions by 15.56–21.31%. The hybrid coal production process is highly prospective to be implemented in Indonesia, especially in Central Java, South Sumatra and South Kalimantan. The payback period from the hybrid coal industry with a production capacity range of 540 thousand to 4.5 million TPY can be achieved in 10–13 years with a net profit range of IDR 137 billion to IDR 493 billion per year and a net present value range of IDR 285 billion to IDR 1.1 trillion.
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Đulović, Izudin, Rejhana Dervišević i Dževad Forčaković. "GEOLOGICAL CHARACTERISTICS OF THE KOTEZI MINING DISTRICT IN THE BUGOJNO COAL BASIN". Glasnik Rudarsko-geološko-građevinskog fakulteta 10, nr 10 (grudzień 2022): 19–30. http://dx.doi.org/10.51558/2303-5161.2022.10.10.19.
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This paper presents geological characteristic of the deposit Kotezi of the Bugojno coal basin. Regional geological researches were conducted from 1983 to 1987, and detailed from 2014 to the end of 2018. After field research and laboratory tests, the analysis and interpretation of the obtained results was carried out. Based on the determined borders of surface distribution and the research results of the coal deposit Kotezi, proved are four coal layers: II bottom, I bottom, main and roof. Coal of the deposit Kotezi belong to the younger coals, soft to medium hard, no luster (matt), brown to black colored, and have brown streak. Their fracture is plate-like and particleboard. He do not have a distinct lignite structure, except in the lower layers. With their general habitus, they resemble younger brown coals, and belong to humic coals which are relatively low in carbonation. Coal deposit Kotezi is the most important deposit in the Bugojno basin, which is very important due to continuity of coal exploitation. Considering the raw material potential and the possibility of expanding the existing raw material base, the Bugojno coal basin has particular importance for the long-term development of lignite exploitation and its use for thermal energy purposes. Key words: the Bugojno coal basin, Kotezi, coal layers, raw material potential.
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Sharma, Naresh, i Hari Prakash Tiwari. "Techno-economic assessment for metallurgical coals: a ‘value-in-use’ approach". Metallurgical Research & Technology 121, nr 3 (2024): 306. http://dx.doi.org/10.1051/metal/2024026.
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The optimization of coke cost is the most significant cost-controlling factor for hot metal production. Therefore, worldwide cokemakers always have extra pressure from management to produce superior quality coke with inferior raw materials and optimal costs. Coke quality is crucial in blast furnace operation regarding cost and productivity. The quality of coke is significantly influenced by the quality of different categories, viz., prime hard coking coal, hard coking coal, soft coking coal and semi-soft coking coal of individual coals used in the coal blend. The impacts of these coals directly influence coke properties because all coals have an inherent characteristic with different coking potentials in terms of value-in-use (VIU). Also, the technological and techno-commercial change of the metallurgical coal market of today differs from past decades. Likewise, the future metallurgical coal market will vary from today’s market. Therefore, a process for assessing/evaluating the coking potential of metallurgical coal shall be used for appropriate value-in-use to produce quality coke with the optimum cost. The composite coking potential methodology served the value-in-use purpose and was successfully implemented. The paper describes the significance of the value-in-use of metallurgical coal to evaluate the most economically favourable technique for producing the desired coke quality.
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Dubrovsky, V. A., Y. V. Isakov i I. I. Potapov. "Water-Coal Suspension Preparation Using Electrohydraulic Coal Breakage Method". Materials Science Forum 870 (wrzesień 2016): 657–60. http://dx.doi.org/10.4028/www.scientific.net/msf.870.657.
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This paper presents the results of an investigation into obtaining water-coal suspension from brown coals of Kansk-Achinsk basin using the electrohydraulic method. The obtained results are the basis for developing the technology of obtaining water-coal suspension using electrohydraulic crushing.
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Malinnikova, Olga, Dmitry Uchaev, Denis Uchaev i Vasiliy Malinnikov. "The study of coal tectonic disturbance using multifractal analysis of coal specimen images obtained by means of scanning electron microscopy". E3S Web of Conferences 129 (2019): 01017. http://dx.doi.org/10.1051/e3sconf/201912901017.
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The possibility of using a multifractal approach to study the tectonic disturbance of coals has been investigated. The relationship between the coal disturbance and the asymmetry of fractal spectra of coal images obtained by means of scanning electron microscopy (SEM) is revealed: it has been established that undisturbed coals are characterized, as a rule, by a symmetric fractal dimension spectrum, and the disturbed coals are described by a fractal spectrum with some degree of asymmetry. It is shown that if fractal spectra of images have a symmetric appearance, then brightness distributions of these images are well fitted by a lognormal curves and parameters of these fittings can be estimated through characteristics of the fractal spectra. By using multifractal analysis of images for more than 140 test coal specimens from the quiet zone of a seam and the outburst zone, differences in the brightness distributions for images of coals with various degrees of disturbance were revealed. The basis of the research is the assumption that differences in the structure of disturbed and undisturbed coals are reflected in histograms of the brightness distributions for images of coal specimens. According to the results of multifractal analysis of images for the test coal specimens, it was established that the brightness distributions for images of the surface of undisturbed coal specimens are lognormal, while the brightness distributions for images of the surface of highly disturbed coal specimens, in most cases, deviate from the lognormal one. The conducted studies allow us to conclude about the applicability of the multifractal approach for assessing the degree of coal disturbance using digital images of coal specimens.
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Hamdani, Ahmad Helman, Agus Didit Haryanto i Muhamad Iqbal. "COAL STRUCTURAL CHARACTERISTICS OF BAYAH FORMATION BASED ON X-RAY DIFFRACTION ANALYSIS". International Journal of Research -GRANTHAALAYAH 10, nr 2 (28.02.2022): 28–34. http://dx.doi.org/10.29121/granthaalayah.v10.i2.2022.4495.
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The coal of Bayah Formation in Lebak Regency, Indonesia have been subjected to attenuated to X-ray diffraction (XRD), to study their chemical and structural characteristics. X-Ray Diffraction (XRD) has been widely used throughout the world and has high accuracy in identifying the molecular structure of coal. Curve-fitting analysis was employed to characterize coal structural. Based on ASTM, the coal rank from this area is high-volatile bituminous B. The research results show all coals have the similar coal structural crystallite characteristics. The value of d002 is in the range of 3.87 to 3.96, reflecting the coals have a low content of crystalline structure. The crystallite height (Lc) and diameter (La) were increase, while d002 decrease in relation of more mature coals. Due to structural parameters (d002, Lc and La) the coals of Bayah Formation dominantly by disordered amorphous structure, with small amount crystallite structure
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Zhuikov, A. V., D. A. Loginov, G. R. Mongush, S. V. Chicherin i N. A. Zemlyansky. "Thermogravimetric analysis of the combustion of Tuva coals before and after their carbonization". iPolytech Journal 26, nr 2 (5.07.2022): 270–83. http://dx.doi.org/10.21285/1814-3520-2022-2-270-283.
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The process of combusting Tuva coals before and after their carbonization was studied using the methods of thermogravimetric analysis and electron microscopy. Coal samples were subjected to thermomechanical and elemental analysis, which revealed a higher content of volatile substances in Kaa-Khem coal (47.5 %) compared to Chadan coal (10 %). Following carbonization, a decrease in volatile substances to 11.5 % and 9.3 %, respectively, was observed. The conducted thermogravimetric analysis showed the ignition temperature of the coke residue of the Kaa-Khem and Chadan coal samples to increase by 76 °C and 90 °C, respectively, after carbonization. The burnup temperature of the coke residue after carbonizing (723 °C) Kaa-Khem coal samples remained effectively the same, while the Chadan coal showed an increase from 704 °C to 727 °C. The carbonization of coals was established to decrease the maximum reaction rate from 19 % per min to 10% per min for Kaa-Khem coal and from 26 % per min to 11 % per min for Chadan coal. The process of combusting the coke residue after coal carbonization was found to shift into the region of higher temperatures: from 448–723°C to 524–724°C for Kaa-Khem coal and from 436–704 °C to 526–727 °C for Chadan coal. A morphological analysis of the surface of coal particles after carbonization showed the appearance of larger-size pores and cracks on the surface of carbonates compared to coal before carbonization. The conclusion is made that the content of volatile substances, rather than the developed pore structure, comprises the main factor in improving the combustion characteristics of Tuva coals under the conditions of non-isothermal heating before and after their carbonization.
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Qiu, Feng, Dameng Liu, Yidong Cai, Ning Liu i Yongkai Qiu. "Methane Adsorption Interpreting with Adsorption Potential and Its Controlling Factors in Various Rank Coals". Processes 8, nr 4 (27.03.2020): 390. http://dx.doi.org/10.3390/pr8040390.
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Water content, metamorphism (coal rank) particle size, and especially pore structure, strongly influence the adsorption capacity of coal to methane. To understand the mechanism of methane adsorption in different rank coals, and its controlling factors, isothermal adsorption experiments with different coal ranks, moisture contents and particle sizes at the temperature of 303.15 K were conducted. In addition, the pore structures of coals were investigated through N2 adsorption/desorption experiments at the low-temperature of 77 K for selected coals from the Junggar Basin of NW China, Qinshui Basin and Ordos Basin of north China. Moreover, the adsorption potential of methane on the surface of the coal matrix was calculated, the controlling factors of which were discussed. The obtained methane isothermal adsorption result shows that the Langmuir volume (VL) of coal is independent of the particle size, and decreases with the increase of moisture content, which decreases first and then increases when the coal rank increases. Combined with the pore structure by the N2 adsorption at 77 K, VL increases with the increase of pore surface area and pore volume of coal pores. Besides, the adsorption potential of all selected coals decreased with the increase of the methane adsorption volume, showing a negative relationship. The interesting phenomena was found that the surface adsorption potential of the coal matrix decreases with the increase of moisture content, and increases with the decrease of particle size at the same pressure. With the same adsorption amount, the adsorption potential on the surface of coal matrix decreases first, and then increases with the increase of coal rank, reaching a minimum at Ro,m of 1.38%, and enlarging with the increase of pore surface area and the pore volume of coal pores. These findings may have significant implications for discovering CBM accumulation areas and enhancing CBM recovery.
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Steer, Julian, Mark Greenslade i Richard Marsh. "A Comparison of Laboratory Coal Testing with the Blast Furnace Process and Coal Injection". Metals 11, nr 9 (17.09.2021): 1476. http://dx.doi.org/10.3390/met11091476.
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The injection of coal through tuyeres into a blast furnace is widely adopted throughout the industry to reduce the amount of coke used and to improve the efficiency of the iron making process. Coals are selected depending on their availability, cost, and the physical and chemical properties determined by tests, such as the volatile matter content, fixed carbon, and ash content. This paper describes research comparing the laboratory measured properties of injection coals that were used over a two-month production period compared to the process variables and measurements of the blast furnace during that study period. In addition to the standard tests, a drop tube furnace (DTF) was used to compare the burnout of coals and the char properties against the production data using a range of statistical techniques. Linear regression modelling indicated that the coal type was the most important predictor of the coal rate but that the properties measured using laboratory tests of those coals were a minor feature in the model. However, comparisons of the Spearman’s correlations between different variables indicated that the reverse Boudouard reactivity of the chars, prepared in the DTF from the coals, did appear to be related to some extent to the coal and coke rates on production. It appears that the constant process adjustments made by the process control systems on the furnace make it difficult to identify strong correlations with the laboratory data and that the frequency of coal sampling and the coal blend variability are likely to contribute to this difficulty.
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Singh, Alpana, i B. D. Singh. "Coal Petrology - A shifting role from coal utilization to fuel exploration". Journal of Palaeosciences 57, nr (1-3) (31.12.2008): 257–64. http://dx.doi.org/10.54991/jop.2008.243.
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Coal petrology deals with the study of microscopically recognizable remains of vegetal source matter, termed 'macerals', which for convenience are classified and categorized into three main groups- vitrinite (O2-rich), liptinite (H2-rich) and inertinite (C-rich). Each maceral being specific in its origin, evolution and environmental conditions during genesis has tremendous interpretative value. Vitrinite-rich coals form in anaerobic (wet-reducing) condition, whereas aerobic (dry-oxidative) condition results into the formation of inertinite-rich coals. Macerals of the liptinite group originate in acidic-wet conditions of swamp. Optical properties (reflectance and fluorescence) and quantitative estimations of coal micro-constituents overall reflect the chemical properties and thus help in various interpretations. The studies are convincingly utilized to predict the suitability of coal for specific economic and industrial purposes. Currently, the petrological investigations are being utilized to interpret the potentiality of coal for methane that originates during the time and pressure induced diagenetic and catagenetic stages of coal formation.
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Sun, Li Mei, i Jiang Wu. "Biological Anaerobic Treatment for Low-Rank Coal Preparation". Advanced Materials Research 361-363 (październik 2011): 328–31. http://dx.doi.org/10.4028/www.scientific.net/amr.361-363.328.
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The effect of microbiological treatment of low-rank coal with an anaerobic microbial consortium on theirs characteristics and composition has been inwestigated. A large amount of pyrite sulfur is removed and coal ash is decreased with anaerobic conditions in closed flask. After biological treatment of these low-rank coals in a continuously operationg flow reactor without air blowiong and with everyday aeration, coal ash reduction is found to be more significant under conditions of reactor aeration due to activation of facultative microorganisems. In some time, some metals are removed from two kinds of low-rank coals, includiing iron, manganese, potassium, lithium, toxic and trace metals. The exchange of elements between coal and mineral culture medium depends on coal rank. Metal leaching is higher for higher rank coal.
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Wu, Guo Fang, Qing Cai Liu, Yuan Pei Lan, Jian Yang i Wei Gao. "Study on the Form of Mercury in Chinese Coal". Advanced Materials Research 838-841 (listopad 2013): 1903–6. http://dx.doi.org/10.4028/www.scientific.net/amr.838-841.1903.
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Study on the forms of mercury is helpful to remove Hg from coal or flue gas more effectively. This paper focus on the coal from three main production base of China, and the Hg content in coal samples was measured by Zeeman effect-mercury analyzer (Lumex RA-915+and RP-91). Moreover, the chemical composition and main phase in coal sample were studied by XRF and XRD. The research results show the Hg content has a close rotation with Si and Al in coals. With the increasing of Si and Al there is more Hg in coals, it further prove the main form of Hg in coals is intergrowth with clay.