High Inertinite Research Articles

Palaeoenvironmental and stratigraphical implications of the palynoflora and macro–charcoal from the early Permian of the Chuperbhita Coalfield, Rajmahal Basin, Jharkhand, India

Palynological and macro–charcoal studies have been carried out on fossiliferous material from the upper seam of the Barakar Formation of Simlong Open Cast Mine (OCM), Chuperbhita Coalfield, India. The palynoassemblage exhibits a dominance of non– striate bisaccate pollen, mainly Scheuringipollenites, and a subdominance of striate bisaccate pollen assignable to Faunipollenites, suggesting an early Permian age (Artinskian). The presence of macro–charcoal indicates the occurrence of wildfire at the time of deposition of the Barakar Formation at Simlong OCM. The composition of the palynological assemblage, as well as anatomical details of the macro–charcoal, indicate that the source vegetation was dominated by gymnosperms. The non–abraded edges of many charcoal fragments suggest that the charcoal has not been transported over a long distance, indicating local to regional fires. Together with previous records of macro–charcoal, and the high inertinite contents of many Permian coals from India, this study further supports the widespread occurrence of palaeo–wildfires as frequent sources of disturbance in continental ecosystems in this part of Gondwana during the early Permian.

Source of inorganic components in the Middle Jurassic inertinite-rich coals of the Southern Ordos Basin, China: With emphasis on formation of Sr- and Ba-bearing minerals

The Middle Jurassic coal seams located in the southern Ordos Basin display notably high concentrations of barium (Ba) and strontium (Sr). To acquire a comprehensive understanding of the source and occurrence of the elevated contents of Ba- and Sr-bearing minerals and their formation mechanism in the coal, a suite of petrological, mineralogical, and geochemical analyses was conducted on the Middle Jurassic coals of the Gaojiapu mine (No. 4 Coal) from the Binchang mining area, using optical microscopy, field emission-scanning electron microscopy, X-ray diffraction, X-ray fluorescence, and inductively coupled plasma mass spectrometry. The results indicate that the No. 4 Coal is a high volatile B bituminous coal, which is characterized by low ash, medium sulfur, and high inertinite contents. The modes of occurrence of minerals identified in the coal, including calcite, dolomite, pyrite, quartz, kaolinite, anatase, barite, and celestine, indicate that the No. 4 Coal may have been subjected to multiple stages of solutions injection. Barium and Sr in the investigated coals are significantly enriched, exhibiting maximum values of 19738 μg/g and 9932 μg/g, respectively, while concentrations of other trace elements are generally depleted. Barite and celestine, generally coexisting with carbonate minerals, commonly occur as cell- and fracture-fillings. Furthermore, the strong correlation coefficients (r) for Ba vs. Ca + Mg and Sr vs. Ca + Mg (0.78 and 0.61, respectively) indicate that most barite and celestine have a close association with carbonate minerals of epigenetic origin. The highly elevated concentrations of Ba and Sr are thought to be primarily derived from solutions leaching barite deposits developed in the Qinling Orogenic Belt, which is located in the south of the Ordos Basin. When mapped spatially, the distributions of Ba and Sr concentrations are fan-shaped, decreasing from the NW to the SE of the mining area. Meteoric water containing dissolved CO2 induced partial dissolution of carbonate rocks, and during this process, selected metal ions (e.g., Ca2+, Mg2+, Al3+, Si2+, Fe2+, Ba2+, and Sr2+) were redistributed and subsequently migrated along fracture zones to the coal seam. The fracture systems and abundant cavities within inertinite in the coal provided sufficient space and conduits for solutions migration.

Applicative Coal Petrology for Industries: New Paradigms

Abstract Coal petrology plays a significant role in understanding coal behaviour during various industrial processes such as carbonization, gasification and liquefaction and helps in characterizing them accordingly. Proper use of fluorescence microscopy and vitrinite reflectance measurement is crucial; carbonization study shows that maceral composition and rank affect the thermoplasticity wherein vitrinite contributes most to the coke formation. Further, the vitrinite is catalyzed by the presence of exsudatinite. Liptinite, when associated with vitrinite, lowers the viscosity of coal during coke making. Coal petrology is successfully used to assess suitability of a coal for coking to predict coke strength and to evaluate coal for coal-blend designing. Composition, structure and behaviour of coke are revealed through petrographic study. The stability and reactivity of coke can also be realised through microscopy. Gasification of coal is performed best in bituminous coal while it is expensive in case of low rank or low grade coals. It can be a simple coal gasification, fixed bed gasification, fluidized-bed gasification, entrained-flow and molten-bath coal gasification. Though any coal may be used for gasification but coal with high reactive components are more suitable but bituminous coal with high inertinite is also suitable as per few researchers. Some minerals have catalytic effect while others act as inhibitors. Elemental composition of organic and inorganic matter of coal, its surface characteristics, porosity and intrinsic reactivity have important bearing on efficiency of gasification. Coal liquefaction is a clean fuel technology which requires proper petrological characterization of coal before processing it. Rank and type of coal along with its composition influence the liquefaction behaviour. Thus, it is imperative to carry out a complete coal microscopy before coal is utilized for making coke/coke-blend or liquid and gaseous hydrocarbon.

Widespread wildfires linked to early Albian Ocean Anoxic Event 1b: Evidence from the Fuxin lacustrine basin, NE China

Wildfires are an important source of disturbances in the Earth's system and are of great significance for understanding the interactions between environmental, atmospheric and vegetation changes over deep time. The early Cretaceous was a “high-fire” interval with frequent and widespread wildfires globally, but the timing and global significance of these wildfire events during this time remain uncertain. We undertook a multi-proxy study evaluating kerogen macerals, inertinite reflectance, and polycyclic aromatic hydrocarbons (PAHs) from mudstones to characterize wildfire activity in the Albian coal-forming Fuxin lacustrine Basin, and correlate these with (i) environmental and floral changes on land, and (ii) well-dated marine events including the early Albian Oceanic Anoxic Event 1b (OAE 1b), to consider their environmental and climatic significance. The presence of high inertinite contents demonstrate that multiple, widespread wildfire events occurred during the early Albian, which are correlated stratigraphically to the Kilian, Paquier and Leenhardt sub-events of the early Albian OAE 1b. Inertinite reflectance values ranging from 0.6% to 3.8%Ro show that wildfires in the early Albian were dominated by ground fires, with a smaller proportion of surface fires and almost no crown fires. Atmospheric oxygen concentration (pO2) levels, estimated from inertinite contents, attained ~25% during the early Albian, which exceeded the present atmospheric oxygen level of 21% and was able to support sustained combustion. Climatic conditions and frequent wildfire activity in the early Albian might have acted as an important control on vegetation distribution and diversification, which possibly further promoted the evolution of early angiosperms during the early Cretaceous. Wildfire activity resulted in the burning and destruction of both vegetation and soil structure, enhancing the post-fire erosion associated with intensified continental weathering under warmer and more humid conditions during the early Albian OAE 1b interval. These episodes of high wildfire activity correlate with high nutrients and organic matter levels in lakes and thereby contributed to eutrophication and anoxia in lacustrine and in contemporaneous oceanic systems.

Sulfur, lead, and mercury characteristics in South Africa coals and emissions from the coal-fired power plants

Coal-fired power plants (CFPPs) are the dominant source of electricity in South Africa due to coal abundance in the country. However, emissions of SO2, Pb, and Hg have raised serious environmental and public health concerns. Hence, to reduce emissions and utilize coal efficiently, it is essential to estimate emissions trends, understanding existential forms of the elements in coals, and their affinities to minerals, organic matter, and pyrite. Therefore, this paper aimed to assess the forms of elemental occurrence of sulfur (S), lead (Pb), mercury Hg affinities in the coals using statistical correlations and their isotopic compositions. This study also estimated SO2, Pb, and Hg emissions from 1971 to 2018 from the CFPPs based on activity data and emission factors. Based on the results, South African coals mainly comprise equivalent fractions of organic and pyritic S. The Pb were correlated with ash content (R = 0.61), Si, Al, and Ti, which indicates clay mineral-bound Pb. However, the highest Pb206/Pb207 and the lowest Pb208/Pb206 in South Africa coals which contain high inertinite (organic matter) and low S, also reveal organically associated Pb. Similarly, clay minerals linked Hg appeared as of Hg relationship with ash (R = 0.641) and major elements, and the remaining could be an organic matter associated. As an organic matter-associated element least cleanability and readily oxidizing nature, burning South African coals containing a substantial quantity of organic S and organically bound Pb and Hg without washing results in higher emissions. The estimated SO2, Pb, and Hg emissions were 355.84 Gg, 168.91 tons, and 4.17 tons in 1971, and increased to 1468.13 Gg, 696.89 tons, and 17.20 tons in 2018, respectively. The values approximately increased by a factor of 4.

Organic geochemical characteristics of bark coal in Changguang area: evidence from aromatic hydrocarbons

Seven coal samples were collected from Changguang area, a typical bark coal field in Zhejiang Province, China. The organic geochemical characteristics and depositional environment of bark coal were studied by Rock–Eval pyrolysis, gas chromatography (GC), and gas chromatography–mass spectrometry (GC–MS) analysis. The results show that all samples are type II kerogen. The values of total organic carbon (TOC), potential yield (S1 + S2), and hydrogen index of these samples ranged from 65.80 wt%–87.00 wt%, 170.43–232.89 mg HC/g, and 234–295 mg HC/g TOC, respectively. In aromatic hydrocarbons compounds of bark coal samples, the phenanthrene series occupy the largest proportion (43.48%–53.74%), followed by the dibenzothiophens (7.33%–16.53%). The distributions of naphthalenes, diphenyls, and chrysene of the samples indicate the source inputs are mainly derived from terrestrial higher plants. Furthermore, the ratios of naphthalene and phenanthrene series compounds reveal the samples are in the mature stage. Some biomarkers (Pr/Ph and C35/C31–35 homohopane), aromatic hydrocarbons (fluorene, dibenzofuran and dibenzothiophene), and high inertinite contents (14.7%–41.8%) suggest that bark coal was formed under relatively oxic conditions and was influenced by marine or brackish lakes environment.

Determination of total and fine airborne dust in coals

Issues on evaluation of coals ability to liberate airborne dust during transportation and transloading are nowadays relevantly current. In the current work, a new method was presented for evaluation of dust contents in coals. It is based on modeling of the processes of coals transloading and transportation. The essence is to stir coals sample of size <3mm at a constant rotation rate with a simultaneous passing a fixed volume of air through a filter system and determining the total airborne dust content and dust class sizes more or less than 10 microns. During the tests, a sample of commodity coal is used as a residue of a sieve analysis of the representative coal sample after the sieve of 3 mm. Experiments were held at two hard coals of the Kuznetsk coal basin differing in their metamorphism degree and petrographic composition. It was established that within the measurement error, the total amount of airborne dust able to be released during transloading for both the considered samples is comparable. On the other hand, the size classes distribution for dust particles over or less than 10 microns varies significantly and depends on the coals rank and petrographic composition. High inertinite contents determines, presumably, the increase of fine dust particles (less than 10 microns) in the total airborne dust released.

Re-evaluation of depositional models for the lower Permian Patchawarra Formation, Cooper Basin, South Australia: implications for petroleum exploration

The Late Carboniferous–Triassic Cooper Basin is Australia’s most prolific onshore petroleum province. The lower Permian Patchawarra Formation, which is up to 680 m thick and consists of up to 10% coal, is a major exploration target in the basin. Eighteen cores through the formation have been logged to re-evaluate the existing fluviolacustrine depositional model. The siliciclastics form fining- and coarsening-upward sequences that are 1–10 m thick. They are predominately fine-grained with abundant lenticular bedding, wavy bedding and thinly interlaminated siltstones and clays resembling varves. Granules and pebbles, interpreted as dropstones, are present throughout the formation. Coal beds are up to 60 m thick and rich in inertinite. Other than the coal beds, there is little evidence of the establishment of terrestrial conditions: roots are rare and there are no siliciclastic palaeosols. The siliciclastics are interpreted as the deposits of a large glaciolacustrine system, with the fining-upward successions deposited in subaqueous channels cut by hyperpycnal flows and the coarsening-upward successions deposited as overbank splays between those channels. Hyperpycnal flows may have resulted from sediment-laden cold water emanating from glacially-fed rivers, similar to those seen in many large glacial lakes in high latitudes and altitudes today. Much of the coal is interpreted as the accumulation of peats from floating mires that covered large parts of the glaciolacustrine system at certain time intervals. The high inertinite content of many coals is interpreted as the decay of organic matter within the floating mire. These new interpretations have the potential to enhance reservoir characterisation within the basin.

Quantitative characterization of low-rank coal reservoirs in the southern Junggar Basin, NW China: Implications for pore structure evolution around the first coalification jump

Abstract The assessment of coalbed methane (CBM) reservoirs can provide insights into the evolution of the pore structure systems around the first coalification jump (FCJ). The southern Junggar Basin, a typical low-rank coal-bearing basin in northwestern China, has been of interest to scientists and policy-makers due to its abundance of CBM resources and favourable conditions for CBM enrichment. A total of 28 coal samples from the Middle Jurassic Xishanyao Formation collected from 11 sampling sites in the central segment of the southern Junggar Basin were analyzed in this study. These samples were quantitatively characterized and comprehensively evaluated using macroscopic to nanometer-scale methods including macroscopic coal description, proximate analysis, vitrinite reflectance measurements, maceral analysis, low pressure nitrogen adsorption (LPNA), scanning electron microscopy (SEM), mercury intrusion porosimetry (MIP) and nuclear magnetic resonance (NMR). The results show that the Xishanyao low-rank coals are characterized by low moisture contents, low or low-medium ash yields (eastern and western parts), high volatile matter contents, moderate vitrinite contents, and high inertinite contents. The physical property of the Xishanyao coals generally displays heterogeneity, with the specific surface area, the total pore volume, the air permeability and the transverse relaxation time (T2) ranging from 0.116 to 15.983 m2/g, 0.461 × 10−3 to 13.37 × 10−3 cm3/g, 0.001 to 151.66 mD (0.987 × 10−6 to 0.149 μm2) and 1.44–174.22 ms, respectively. A new parameter, namely micropore volume proportion per unit nano-meter, is proposed. Micropore and transition pore volume per nm, specific surface area, total pore volume, DN1 and DN2 (LPNA fractal dimension) all first increase, then decrease and finally increase with rising coal rank, while the maximum and minimum values of the maximum vitrinite reflectance (Ro, max) occur at 0.58–0.59% and 0.65–0.66%. The boundary of Ro, max corresponding to the FCJ can be further defined from 0.5-0.6% to 0.58–0.59% based on the evolution of adsorption pore structures. Thus, pore structure parameters related to adsorption capacity are controlled predominantly by coal rank. In addition, tectonic deformation has a strong impact on seepage pore structure but only a slight impact on that of adsorption pore, which leads to an ambiguous correlation or a complex trend between mesopore, macropore content, DMIP (fractal dimension of MIP) and coal rank around the FCJ. This study reveals the complex variation of pore structure evolution of low-rank coals and the significant influence of the FCJ on physical properties of coalbed methane reservoirs.

Perchloroethylene (PCE) adsorption on coal macerals as derived from micro-FTIR spectroscopic analysis and mapping of the C=C bonds from PCE

ABSTRACT Organic liquids are used to prepare the density medium to produce clean coal composites for coal quality and coking test evaluations during the coal exploration stage. Perchloroethylene (PCE) is commonly used as a density medium for this procedure; however, it has been shown before that PCE affects Gieseler Fluidity and Ruhr Dilatation indices of coal, as well as the quality of the resulting coke. It was also found that PCE has a negative effect on the coking properties of coals with a high inertinite content. This paper investigates the adsorption of PCE on various coal maceral surfaces using micro-Fourier Transform Infrared Spectroscopy (micro-FTIR) analysis to observe the changes in the absorbance of the double carbon bond C = C (C = C absorbance peak is used as a marker to indicate the presence of PCE) before and after PCE was applied onto their surfaces. The micro-FTIR mapping of absorbance intensity of the C = C bond on coal macerals showed an increasing trend in the presence of these bonds on the surface of all macerals with the time after exposure to the PCE. The SEM- energy-dispersive X-ray spectroscopy was used to analyze the composition of minerals associated with fusinite and semifusinite, as they were filling the pores in these macerals.

Early Pennsylvanian ombrotrophic mire of the Prokop Coal (Upper Silesian Basin); what does it say about climate?

The Lower Pennsylvanian (Kinderscoutian) Prokop Coal (Coal No. 40), the erosional remnant of which covers about 5000 km2, is the thickest seam of the Upper Silesian Basin situated along the Czech – Polish border. This basin-wide coal is unusual in its thickness and high inertinite and very low ash contents. In the Czech sector, this coal merges with the overlying Coal No. 39 into a single 9 to 15 m thick seam. Maceral analyses of an approximately 11 m thick section of these two merged coals show changes in the proportion of vitrinite (24.7 – 88.0 %) and inertinite (8.5 – 56.8 %) in cycles between 50 and 190 cm thick. The increase of inertinite in the lower part of coal cycles coincides with a dulling-upward trend, which records a drying-upward succession due to a slowing of accommodation rate relative to plant biomass productivity. This succession is interpreted as a transition from rheotrophic to ombrotrophic conditions. The brightening-upward succession in the upper part of coal cycles records a wetting-upward trend due to water table rise, resulting in restoration of rheotrophic conditions that supported humification under the regional ground water table. The sudden shift from inertinite-rich to vitrinite-rich coal at the base of brightening-upward successions points to a period of degradation and lowering of the peat dome. The coal cycles within the studied seam section probably preserve a succession of spatially overlapping but genetically independent mires bounded by degradation surfaces. The alternation between mires with contrasting hydrological regimes is interpreted as a record of base-level fluctuations of climatic causation of sub-Milankovitch periodicities. Early Pennsylvanian climate for various stages of mire development is inferred from analogy with modern tropical mires in SE Asia.

Processing Nigerian coal deposits for energy source

Some coal deposits in Nigeria were assessed through geochemical Rock Eval pyrolysis, organic petrology and combustibility studies to characterize them and to determine their suitability as an energy source. The following correlations were obtained. Rock Eval hydrogen indices (HI) correlate proportionally with the petrographical liptinite content; oxygen indices (OI) correlate proportionally with the combustibility time and with the petrographical inertinite content (made up mainly of fusinite). The coals with higher values of OI correlating with high inertinite content produce more visible smoke during combustion, while those with lower OI and higher liptinite content produce less visible smoke (smoke perception). The Okaba coal deposits in the Northern Anambra Basin contain higher values of HI, lowest values of OI and inertinite content and correspondingly had the shortest combustibility time. It also has very little visible smoke and assumed to be the most suitable for smokeless fuel production and electrical energy generation. Using theses parameters to characterize the other coals, the Owukpa and Omelehu come next as a good coal energy source. The Ogboyaga coals have relatively high OI and inertinite contents; it produced the most visible smoke. The Lafia-Obi coals with high inertinite content took the longest time to bring the same volume of water to boiling point, compared to the other coals. Defusinization experiments in which samples were digested with eight types of organic acids gave results that show that Benzoic and Formic acids can be used to clean the coals (to some extent) to make them more suitable as environmental-friendly energy source.

A Nuclear Magnetic Resonance study: Implications for coal formation in the Witbank Coalfield, South Africa

In this study, carbon-13 cross-polarization magic-angle-spinning solid-state nuclear magnetic resonance (13C CP-MAS SS NMR) was undertaken on a parent coal sample and its density-fractionated derivatives, an inertinite-rich and a vitrinite-rich sample, obtained from the Witbank Coalfield of South Africa (medium rank C bituminous coal). The formation of inertinite macerals has been extensively researched and the conclusions remain largely controversial. However, most research has been confined to northern hemisphere coals, which are typically dominated by vitrinite. South African coals are widely known for their high inertinite content. Earlier workers have ascribed the inertinite macerals, in their diversity, to aerial oxidation. However, this oxidation-only pathway fails to recognize that inertinite macerals can form through other processes such as charring of plant matter. Microscopically, charred matter possesses anatomical structures that closely resembles those observed in inertinite macerals, with lignin and/or cell walls largely preserved, perhaps mechanically fragmented or compressed in some instances. Based on the NMR structural parameters, the average aromatic cluster size in the inertinite-rich sample (petrographically dominated by fusinite, semifusinite of varying reflectance, and inertodetrinite) corresponds to monocyclic, 6-aromatic carbon rings. In the vitrinite-rich sample of the same coal, the cluster sizes are larger, corresponding to multi-ring aromatic hydrocarbons. The 6-carbon rings in the inertinite-rich sample are interpreted to correspond to guaiacol and syringol, the principal products of low-temperature (below 400 °C) lignin pyrolysis. Since charring depletes cellulose and moisture, fire-affected plant matter is interpreted to have a lower compaction potential than vitrinite-forming material, sustaining 6-aromatic carbon ring isolation in the former. Lignin-derived aromatic rings in compactable plant matter merge to form the multi-ring clusters present in the collotelinite- and collodetrinite-rich sample of the same coal.

Structure and combustion characteristics of high inertinite coal demineralized by stepwise chemical methods

ABSTRACT A high inertinite coal was chosen and its stepwise demineralization samples were prepared. Their structures and combustion characteristics were researched by proximate and ultimate analyses, N2-adsorption isotherms, and thermogravimetric analysis methods. The results show that the specific areas and pore volumes reduce and the average pore diameters enlarge when the minerals in coal samples are gradually removed by deionized water, HCl, and HF. The structure of a coal sample is nearly unchanged while they are treated with deionized water and HCl, and their chemical composition changes in a way when they are treated with HF. A small amount of water soluble minerals in coal obstruct and the majority acid soluble minerals promote coal sample combustion. The bigger the specific areas, the higher the coal sample combustion activity. The moderate moisture in coal can promote sample combustion.

Fires in the mire: repeated fire events in Early Permian ‘peat forming’ vegetation of India

Macro‐charcoal, as direct evidence of palaeo‐wildfires, is a common constituent throughout an Early Permian (Cisuralian) inertinite‐rich coal seam from the Dhanpuri Coal Mine (Barakar Formation, Sohagpur Coalfield, Madhya Pradesh, India). The continuous presence of macro‐charcoal within this particular seam demonstrates that fires occurred repeatedly in the source vegetation of the seam. Based on these macro‐charcoal remains, an anatomical assessment of the diversity and taxonomic composition of the vegetation, which experienced wildfires and contributed to the formation of peat/coal, is provided. The vegetation that experienced regular fires was dominated by gymnosperms, with a minor component of pteridophytes. The results also support previous studies, which suggest a pyrogenic origin for the high inertinite contents of many Permian coals within Gondwana. Copyright © 2016 John Wiley & Sons, Ltd.

The Effect Of The Petrographic Composition On The Variation Of CRI And CSR Indices In The Pniówek Deposit In The Sw Part Of The Upper Silesian Coal Basin (Poland)

Abstract The characteristics of variation of the CRI (Coke Reactivity Index) and CSR (Coke Strength after Reaction) indices as well as the variation of the petrographic composition of coking coal in the Pniówek deposit (SW part of the Upper Silesian Coal Basin) have been presented. The area in which the research results have been obtained has a fundamental meaning to the Polish coking coal reserves, which are characterized by high variation both in quality and coalification. So far, no research related to the determination of the CRI and CSR variation in deposits that would be based on pillar samples collected from active workings has been performed for the Polish coking coal deposits. The samples have been obtained from 6 coal seams (Załęże Beds, a part of Mudstone Series-Westphalian A), at depths between −500 and −700 m.a.s.l. The variation of CRI and CSR values has been presented both along the depth of the deposit (vertically) as well as isolines maps (horizontal variations). The relationships between the CRI and CSR index values and the parameters which are fundamental for their values, that is the R vitrinite reflectance and the petrographic composition (content of the Vtmmf vitrinite, Lmmf liptinite, and Immf inertinite macerals) have been analyzed. The examined coking coal of the Pniówek coal mine is characterized by the following values of the analyzed parameters: CRI = 19.9-60.8% (mean of 33.4%), CSR = 24.4-65.3% (mean of 49.5%), R = 0.98-1.14% (mean of 1.08%), Vtmmf = 60-81% (mean of 74%), Lmmf = 4-11% (mean of 7%), Immf = 13-31% (mean of 19%). The analysis of the variation of the coal quality parameters has not indicated evident and distinct vertical variation tendencies. When considered together with the horizontal variation in the E-W direction, in the view of the tectonics of the deposit (strike, dip, course of the main faults), it indicated a relation between the quality parameters and the direction of bed dips. In the deposit of the Pniówek coal mine, presence of coals of various quality has been confirmed. In the east, at greater depths, less coalified coal characterized by lower CRI values and higher CSR values is present. Such coal has a lesser vitrinite content and a high inertinite content. In the western direction (opposite to the dip direction), higher coalified coals, with higher CRI values and lower CSR values occur-these coals have a high content of vitrinite and low part of inertinite. Inversion of coalification has been demonstrated, as the smaller the depth the lower the reflectance of the coal should be, whereas the case in the Pniówek coal mine is the opposite. Such inversion may be related, as it has been demonstrated numerous times, to the occurrence of thermal metamorphism which modified the regional structure of coalification. No evident relationship of CSR and CRI values and the petrographic content of coal has been found, which is exhibited by low values of correlation indices. High content of inertinite in the samples characterized by relatively low values of CRI, relatively high CSR values and the lowest reflectance, however, draws attention. This runs against expectations, as usually the coal with better coking properties is characterized by the lowest content of inertinite macerals. The explanation of this relation requires further research on the inertinite macerals, especially the typically inert macerals (that is fusinite, micrinite and sclerotinite). The found relationship between the CSR and CRI values does not deviate from the data provided in literature from around the world. The correlation of the CSR index and the Pniówek coal mine vitrinite reflectance, however, is only partially consistent with the results relating to other coals. This confirms the difference of the coal in the examined area, which was exhibited many times and which should be connected to a very specific course of the coalification processes, especially the effect of thermal metamorphism.

Effect of bituminous coal properties on carbon dioxide and methane high pressure sorption

High pressure sorption experiments with carbon dioxide and methane were carried out at a temperature of 45°C and at pressures up to 15MPa with three samples of methane-bearing, medium-rank coals in a moisture-equilibrated state using a manometric method. The samples were taken from selected positions of drill cores from exploration boreholes in the Bohemian part of the Upper Silesian Basin, and were characterized by a narrow range of degree of coalification and markedly different petrographic compositions, including a different mineral matter content. The total porosity of the coal samples was between 9% and 10%. A positive correlation was found between the equilibrium moisture in the coal samples and the total abundance of oxygen functional groups determined by FTIR. The excess sorption capacities ranged from 0.78 to 0.91mmolg−1 for CO2 and from 0.45 to 0.52mmolg−1 for CH4, and after recalculation to coal organic matter, the excess sorption capacities increased by up to 14% in the coal with the highest mineral fraction. The highest CO2/CH4 ratio was found in the sample that had the highest inertinite and liptinite content. The experimental isotherm data was fitted by modified Langmuir and Dubinin–Radushkevich sorption isotherms. The parameters obtained by these two methods were in good agreement for carbon dioxide. It was found that the sorption capacity of the organic matter in a coal sample with prevalence of inertinite (63.0vol.%) was lower only by 14% for CO2 and by 18% for CH4 than the sorption capacity of the organic matter in a coal sample with prevalence of vitrinite (65.3vol.%). This provided confirmation that the petrographic composition of a coal has an ambiguous effect.

Methods for Improving Slurry Ability of Yangchangwan Bituminous Coal

Yangchangwan (YCW) bituminous of Ningxia is a weakly reductive coal, which was characterized with low ash content, low sulfur content, low H/C and ash fusion, but high moisture, oxygen, inertinite and alkaline earth metal contents, also difficult to make slurry. Influence of dispersant kind and dosage on YCW CWS rheological behavior was studied using 8 dispersants. Examination was conducted in the lab. The results show that the dispersant and its dosage not only influence the apparent viscosity but also the rheological behavior of CWS. Methyl naphthalene acid salt formaldehyde condensation(MF) is the best dispersant for YCW bituminous coal and the optimal dosage is 1%. CWS were also prepared using compounded dispersants of sodium lignosulphonate and Methyl naphthalene acid salt of formaldehyde condensation and in order to investigate the slurry ability of CWS with compounded dispersants. The results show that compounded dispersants have a greater impact on the liquidity and stability of CWS, the optimal ratio of two dispersant is 3:7. Slurry technologies of blended coals were also studied in this paper, YCW bituminous coal with lower slurry ability , lower static s stability and poor theological behavior and Dafeng(DF) anthracite coal with good properties of CWS and the better theological behavior. The effect of the ratios of two coals on the static stability and viscidity of CWS was studied. The results show that CWS is better static stability ability and viscidity when the chemical additive quantity is at 1 parts per hundred and the ratio of two coals is 3:7.The effects of coal blending on the features of coal-water slurry are nonadditivity. It can effectively improve the concentration of coal water slurry, for coal which has difficulty in preparing coal-water slurry.

Distribution of selected trace elements in density fractionated Waterberg coals from South Africa

Abstract The Waterberg Coalfield, located in the Limpopo Province (north-western area) of South Africa, contains a significant proportion of the South African coal resource. This Permian coalfield typically contains high vitrinite, high ash coals in the Kungurian Grootegeluk Formation, and high inertinite, low ash coals in the Artinskian Vryheid Formation. Four run-of-mine coals and density fractioned samples were analysed to determine their trace element content. The concentrations of most trace elements in the run-of-mine coals exceed the global averages and certain global ranges, and generally exceed values reported for other South African coalfields. Specifically, Hg concentrations are high to very high in all the coals (up to 2.43 ppm in a sample from the Vryheid Formation), Cd and Se concentrations are comparable to or lower than global averages, and As is very low in the Vryheid Formation (1.57 ppm). A sample from the Grootegeluk Formation is enriched in siderophile elements, and a sample from the Vryheid Formation is depleted in chalcophile elements. Studies of the density fractionated samples indicate that Cd exhibits an organic affinity in the Grootegeluk Formation samples, and possibly a pyritic (or sulphide) affinity in the Vryheid Formation sample. Selenium has a greater affinity for the middle, clay-rich density fractions in all samples. Arsenic reports to the mineral-rich sink fractions, specifically the fractions enriched in pyrite. Mercury reports to both the float and sink fractions, indicating an organic and inorganic affinity in these coals, although there is more enrichment in the sink fractions in the Grootegeluk Formation samples, and a definite organic correlation in the Vryheid Formation sample.

Hydrocarbon generation potential and Miocene–Pliocene paleoenvironments of the Kangal Basin (Central Anatolia, Turkey)

This study deals with the organic geochemical characteristics, hydrocarbon generative potential and Miocene–Pliocene paleoenvironments of the Kangal coal district, which developed in a limnic depositional environment and contains the Hamal, Etyemez and Kalburçayırı coal fields in the southern part of the Sivas Basin (Central Anatolia). Around Kalburçayırı, the average thickness of each of the two coal seams approximately 10 m are currently being exploited based on open-cast methods, the coal from which is used by the nearby lignite-fired Kangal power station. An attempt was made to elucidate depositional conditions through proximate and ultimate analyses, coal petrography and the geochemical characteristics of the Kangal coals. These coals have a huminite reflectance value of R max = 0.40%. Accordingly, from the standpoint of coal rank, this is a dull brown coal of the “subbituminous C” type. Huminite is the most widespread maceral type, while gelinites are the most often encountered macerals. Relative to liptinites, the proportion of inertinites is high. On the basis of maceral composition, the depositional environment of the Kangal coals was determined to be either a forest swamp or a lake bottom. The distributions of the C 27 and C 28–C 29 steranes for all these coal samples are very similar (C 29 > C 27 > C 28). Tricyclic terpanes have low concentrations in all samples of the Kangal coals, and are dominated by low molecular weight compounds (C 20–C 24) with a maximum at C 23. Total organic carbon (TOC, wt.%) values of the Kalburçayırı samples are 4.64–30.64 wt.%, in the Hamal samples 0.83–2.53 wt.%, and in the Etyemez samples 8.91–10.39 wt.%. On the basis of T max values, the samples are in the immature-early mature stage. According to Rock-Eval pyrolysis data, the coals have hydrocarbon source-rock potential, but the coaly shales and other organic-matter-rich levels have no hydrocarbon source-rock potential. The high inertinite levels and high vitrinite/inertinite ratios suggest that the Kangal coals have more potential for gas generation than oil.