The Influences of the Rank of Coal on Methane Sorption Capacity in Coals/Wpływ Rzędu Węgla Na Pojemność Sorpcyjną Metanu W Węglach

2014 ◽  
Vol 59 (2) ◽  
pp. 509-516
Author(s):  
Andrzej Olajossy
Keyword(s):  
Sorption Capacity ◽  
Coalbed Methane ◽  
Vitrinite Reflectance ◽  
Sorption Isotherms ◽  
Volatile Matter ◽  
Low Rank ◽  
Hard Coal ◽  
Petrographic Composition ◽  
Methane Sorption ◽  
Indian Coals

Abstract Methane sorption capacity is of significance in the issues of coalbed methane (CBM) and depends on various parameters, including mainly, on rank of coal and the maceral content in coals. However, in some of the World coals basins the influences of those parameters on methane sorption capacity is various and sometimes complicated. Usually the rank of coal is expressed by its vitrinite reflectance Ro. Moreover, in coals for which there is a high correlation between vitrinite reflectance and volatile matter Vdaf the rank of coal may also be represented by Vdaf. The influence of the rank of coal on methane sorption capacity for Polish coals is not well understood, hence the examination in the presented paper was undertaken. For the purpose of analysis there were chosen fourteen samples of hard coal originating from the Upper Silesian Basin and Lower Silesian Basin. The scope of the sorption capacity is: 15-42 cm3/g and the scope of vitrinite reflectance: 0,6-2,2%. Majority of those coals were of low rank, high volatile matter (HV), some were of middle rank, middle volatile matter (MV) and among them there was a small number of high rank, low volatile matter (LV) coals. The analysis was conducted on the basis of available from the literature results of research of petrographic composition and methane sorption isotherms. Some of those samples were in the form (shape) of grains and others - as cut out plates of coal. The high pressure isotherms previously obtained in the cited studies were analyzed here for the purpose of establishing their sorption capacity on the basis of Langmuire equation. As a result of this paper, it turned out that for low rank, HV coals the Langmuire volume VL slightly decreases with the increase of rank, reaching its minimum for the middle rank (MV) coal and then increases with the rise of the rank (LV). From the graphic illustrations presented with respect to this relation follows the similarity to the Indian coals and partially to the Australian coals.

ON THE EFFECTS OF MACERAL CONTENT ON METHANE SORPTION CAPACITY IN COALS / WPŁYW ZAWARTOŚCI MACERAŁÓW NA POJEMNOŚĆ SORPCYJNĄ METANU W WĘGLACH

2013 ◽  
Vol 58 (4) ◽  
pp. 1221-1228 ◽  
Author(s):  
Andrzej Olajossy
Keyword(s):  
Sorption Capacity ◽  
High Pressures ◽  
Sorption Isotherms ◽  
Petrographic Composition ◽  
Methane Sorption

Abstract The problems connected with the sorption capacity of methane in hard coals are constantly subject to various research. In this paper, the influence of the content of macerals mainly vitrinite for the sorption capacity of chosen samples of Polish hard coals was analysed. The analysis was conducted on basis of available from the literature results of resarches of petrographic composition of this coals and methane sorption isotherms. The samples of grained coals contained from 7 ro 76% of vitrinite and their sorption capacity was obtained in the scope of high pressures; 0 < p < 80 bars, on the basis of the equation of Langmuire. In effect, it turned out that the maceral content has a little influence on the methane sorption capacity of coals. This refers mainly to high volatile and middle volatile coals. In the literature concerning this issue simillar effect may be encountered for other coals.

scholarly journals Evaluation of parameters to determine the degree of coal dust explosibility

2014 ◽  
pp. 42-54
Author(s):  
Elkin Casas Herrera ◽  
Astrid Blandón Montes ◽  
Jorge Martin Molina-Escobar
Keyword(s):  
Direct Relationship ◽  
Coal Dust ◽  
Vitrinite Reflectance ◽  
Carbon Particle ◽  
Calorific Value ◽  
Environmental Parameters ◽  
Volatile Matter ◽  
Low Rank ◽  
Fine Grain ◽  
Close Relationship

Coal dust is highly explosive and caused dozens of victims in Colombia. In this research the most important and direct influence on coal dust, especially those that cause combustion and explosion inside the mine factors were analyzed; is important to discuss the characteristics of each coal mined and processed, for actions that do not compromise the integrity of the staff or facilities. Four (4) channel samples of coal exploitation faces with High Volatile Bituminous C from Cerrejón Formation were collected and analyzed: Proximal (moisture, ash, volatile matter, fixed carbon, total sulfur and calorific value ); petrographic (maceral counting and vitrinite reflectance) and Hardgrove mill index. The samples were crushed to obtain fractions corresponding to meshes 200, 270 and 325 considering those sizes could give greater risks of explosion.The analysis showed that there is a direct relationship between the results of the Hardgrove mill index and the degree of explosiveness in the fraction corresponding to 200 mesh, meaning that a higher rate of milling the greater the degree of explosiveness; a direct relationship between calorific inertinite content range and also observed. The 325 mesh fraction for all samples showed the same degree of explosiveness, which indicates that the grain size and the type of coal maceral not influence the content and coal rank. The flash point decreased for finer grains for all samples. Thus, the size of carbon particle is very important as an indicator in the coal-dust explosion factor: finer particles have greater the likelihood of explosion. The percentage of inertinites has a close relationship with the explosivity index, the higher the content of this maceral, coupled with the fine grain, coal dust behaves like a highly explosive element and generate risks in mining operations.Coal rank is an important factor regard to self combustion and explosion of particles with grain sizes greater 200 mesh. If a low rank coal has susceptible and unstable at high temperature elements and this is combined with high volatile matter and some other influential environmental parameters, such as blow air, dust concentration, humidity, and pressure, among others, the ideal combustion and then a likely violent explosion may affect a large portion of mine.

scholarly journals Analysis of the Influence of Coal Petrography on the Proper Application of the Unipore and Bidisperse Models of Methane Diffusion

Energies ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 8495
Author(s):  
Marcin Karbownik ◽  
Jerzy Krawczyk ◽  
Katarzyna Godyń ◽  
Tomasz Schlieter ◽  
Jiří Ščučka
Keyword(s):  
Sorption Kinetics ◽  
Volatile Matter ◽  
Matter Content ◽  
Coal Bed ◽  
Hard Coal ◽  
Carbon Structure ◽  
Methane Sorption ◽  
Methane Diffusion ◽  
Coal Petrography ◽  
Kinetics Of

The analysis of phenomena related to gas transport in hard coal is important with regard to the energetic use of coal bed methane (CBM), the reduction of greenhouse gas emissions to the atmosphere (CO2) and the prevention of natural hazards such as methane hazards and gas and rock outbursts. This article presents issues concerning the feasibility and scope of applying the unipore and bidisperse diffusion models to obtain knowledge concerning the kinetics of methane sorption and its diffusion in the carbon structure, depending on its petrography. Laboratory tests were carried out on coal samples which varied in terms of petrography. Quantitative point analyses were carried out, based on which content of groups of macerals was determined. The degree of coalification of coal samples was also determined based on measurements of vitrinite reflectivity R0 and the volatile matter content Vdaf. Sorption kinetics were also investigated, and attempts were made to adjust the unipore and bidisperse models to the real sorption kinetic courses. This allowed the identification of appropriate coefficients controlling the course of sorption in mathematical models. An attempt was also made to assess the possibility of applying a given model to properly describe the phenomenon of methane sorption on hard coal.

scholarly journals The Impact of Coal’s Petrographic Composition on Its Suitability for the Gasification Process: The Example of Polish Deposits

Resources ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 111
Author(s):  
Barbara Bielowicz ◽  
Jacek Misiak
Keyword(s):  
Coal Gasification ◽  
Negative Impact ◽  
Vitrinite Reflectance ◽  
Low Rank ◽  
Petrographic Composition ◽  
Gasification Process ◽  
Physico Chemical ◽  
Higher Rank ◽  
The Impact ◽  
Selection Of

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.

Application of integrated formationevaluation and three-dimensional modeling in shale gas prospect identification

2020 ◽  
Vol 1 (3) ◽  
Author(s):  
Jin Gao ◽  
Guangdi Liu ◽  
Zhe Cao ◽  
Lijun Du ◽  
Yuhua Kong
Keyword(s):  
Sorption Capacity ◽  
Shale Gas ◽  
Vitrinite Reflectance ◽  
Three Dimensional ◽  
Junggar Basin ◽  
Northwest China ◽  
Wide Distribution ◽  
Methane Sorption ◽  
Northwestern Margin ◽  
Gas Potential

Identifying the shale gas prospect is crucial for gas extraction from such reservoirs. Junggar Basin (in Northwest China) is widely considered to have high potential as a shale gas resource, and the Jurassic, the most significant gas source strata, is considered as prospective for shale gas exploration and development. This study evaluated the Lower Jurassic Badaowan Formation shale gas potential combined with geochemical, geological, and well logging data, and built a three-dimensional (3D) model to exhibit favorable shale gas prospects. In addition, methane sorption capacity was tested for verifying the prospects. The Badaowan shale had an average total organic carbon (TOC) content of 1.30 wt. % and vitrinite reflectance (Ro) ranging from 0.47% to 0.81% with dominated type III organic matter (OM). X-ray diffraction (XRD) analyses showed that mineral composition of Badaowan shale was fairly homogeneous and dominated by clay and brittle minerals. 67 wells were used to identify prospective shale intervals and to delineate the area of prospects. Consequently, three Badaowan shale gas prospects in Junggar Basin were identified: the northwestern margin prospect, eastern Central Depression prospect and Wulungu Depression prospect. The middle interval of the northwestern margin prospect was considered to be the most favorable exploration target benefitted by wide distribution and high lateral continuity. Generally, methane sorption capacity of the Badaowan shale was comparable to that of the typical gas shales with similar TOC content, showing a feasible gas potential.

scholarly journals Synergy of Parameters Determining the Optimal Properties of Coal as a Natural Sorbent

Energies ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1967 ◽  
Author(s):  
Katarzyna Godyń ◽  
Barbara Dutka ◽  
Monika Chuchro ◽  
Mariusz Młynarczuk
Keyword(s):  
Multiple Regression ◽  
Sorption Capacity ◽  
Vitrinite Reflectance ◽  
Sorption Property ◽  
Effective Diffusion ◽  
Gravimetric Method ◽  
Low Rank ◽  
Petrographic Analysis ◽  
Natural Sorbent ◽  
Specific Pore Volume

Selection of the optimal properties of coal as a natural sorbent, both as a sample collected from a seam or of the coal seam itself, requires various parameters to be determined and may not be based on the knowledge of metamorphism degree only. In order to improve the predictions of sorption capacity and the kinetics, analyses of correlation and multiple regression based on the results of laboratory studies were performed for 15 coal samples with various coal rank. The maximum vitrinite reflectance (R0) for low-rank coals was 0.78%–0.85%, and 0.98%–1.15% and 1.85%–2.03% for medium- and high-rank coals, respectively. Coal samples were subjected to technical and petrographic analysis. The gravimetric method was used to perform sorption tests using methane, in order to determine the sorption capacity and the effective diffusion coefficient for each of the coals. Pycnometric methods were used to determine the textural parameters of coals, such as the percentage porosity and specific pore volume. The studies were further supplemented with an evaluation of the mechanical properties of the coals, Vickers micro-hardness, and elastic modulus. This work shows that the statistical multiple regression method enables a computational model including the selected petrophysical parameters displaying synergy with the specific sorption property—capacity or kinetics—to be created. The results showed the usefulness of this analysis in providing improved predictions of the optimal sorption properties of coal as a natural sorbent.

scholarly journals Application of Langmuir and Dubinin–Radushkevich models to estimate methane sorption capacity on two shale samples from the Upper Triassic Chang 7 Member in the southeastern Ordos Basin, China

2016 ◽  
Vol 35 (1) ◽  
pp. 122-144 ◽  
Author(s):  
Lei Chen ◽  
Zhenxue Jiang ◽  
Keyu Liu ◽  
Wenming Ji ◽  
Pengfei Wang ◽  
...  
Keyword(s):  
Sorption Capacity ◽  
Ordos Basin ◽  
Sorption Isotherms ◽  
Upper Triassic ◽  
Organic Carbon Content ◽  
Maximum Sorption Capacity ◽  
Maximum Sorption ◽  
Methane Sorption ◽  
Temperature And Pressure ◽  
Increasing Temperature

A series of methane sorption isotherms were measured at 303 K, 313 K, 323 K, 333 K, and 343 K at pressures up to 12.0 MPa for two shale samples from the Upper Triassic Chang 7 Member in the southeastern Ordos Basin with total organic carbon content values of 5.15% and 4.76%, respectively. Both the Langmuir- and Dubinin–Radushkevich-based excess sorption models were found to well represent the excess sorption isotherms within the experimental pressure range. The maxima of absolute methane sorption capacity fitted by both models are not significantly different. In the current study, the effects of temperature and pressure on methane sorption capacity support the findings that under isothermal condition, methane sorption capacity of organic shale goes up with increasing pressure and under isobaric condition, while it goes down with increasing temperature. Good negative linear relationships between temperature and maximum sorption capacity exist both in the Langmuir and the Dubinin–Radushkevich models. In addition, a good positive linear relation exists between the reciprocal of temperature and the natural logarithm of Langmuir pressure, which indicate that temperature and pressure are really important for methane sorption capacity. The extended Langmuir and Dubinin–Radushkevich models have been improved to calculate the methane sorption capacity of shales, which can be described as a function of temperature and pressure. By means of using the two estimation algorithms established in this study, we may draw the conclusion methane sorption capacity can be obtained as a function of depth under geological reservoir. Due to the dominant effect of pressure, methane sorption capacity increases with depth initially, till it reaches a maximum value, and then decrease as a result of the influence of increasing temperature at a greater depth. Approximately, the maximum sorption capacity ranges from 400 m to 800 m.

scholarly journals Influence of Coal Particle Size on Coal Adsorption and Desorption Characteristics

2014 ◽  
Vol 59 (3) ◽  
pp. 807-820 ◽  
Author(s):  
Lei Zhang ◽  
Naj Aziz ◽  
Ting Ren ◽  
Jan Nemcik ◽  
Shihao Tu
Keyword(s):  
Particle Size ◽  
Sorption Capacity ◽  
Coalbed Methane ◽  
Coal Particle ◽  
Sorption Isotherms ◽  
Ash Content ◽  
Methane Recovery ◽  
Adsorption And Desorption ◽  
Coal Particles ◽  
Desorption Hysteresis

Abstract Accurate testing coal isotherm can play a significant role in the areas of coal seam gas drainage, outburst control, CO2 geo-sequestration, coalbed methane (CBM) and enhanced coalbed methane recovery (ECBM) etc. The effect of particle size on the CO2 and CH4 sorption capacity of bituminous coal from Illawarra, Australia was investigated at 35°C and at pressure up to 4 MPa. A unique indirect gravimetric apparatus was used to measure the gas adsorption and desorption isotherms of coal of different particle sizes ranging from around 150 urn to 16 mm. Langmuir model was used to analysis the experimental results of all gases. Coal particle size was found to have an apparent effect on the coal ash content and helium density results. Coal with larger particle size had higher ash content and higher helium density. The sorption isotherm was found to be highly sensitive with helium density of coal which was determined in the procedure of testing the void volume of sample cell. Hence, coal particle size had a significant influence on the coal sorption characteristics including sorption capacity and desorption hysteresis for CO2 and CH4, especially calculated with dry basis of coal. In this study, the 150-212 um (150 um) coal samples achieved higher sorption capacity and followed by 2.36-3.35 mm (2.4 mm), 8-9.5 mm (8 mm) and 16-19 mm (16 mm) particle size samples. However, the differences between different coal particles were getting smaller when the sorption isotherms are calculated with dry ash free basis. Test with 150 um coal samples were also found to have relatively smaller desorption hysteresis compared with the other larger particle size samples. The different results including adsorption/desorption isotherm, Langmuir parameters and coal hysteresis were all analysed with the CO2 and CH4 gases.

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