Variation of Petrophysical Properties and Adsorption Capacity in Different Rank Coals: An Experimental Study of Coals from the Junggar, Ordos and Qinshui Basins in China

Wang, Yingjin; Liu, Dameng; Cai, Yidong; Li, Xiawei

doi:10.3390/en12060986

Cited by 24 publications

(13 citation statements)

References 36 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, the discrepancies of results of experimental studies show that using the coal rank as the only factor evaluating the sorption capacity of coal is a controversial approach [9,19]. Additionally, the petrographic composition of coal [20][21][22], the porous structure [23], or the tectonic disturbances affecting the structural and textural features of the coal seam [24] disturb the clear picture of the relationships described in the literature. It is also known that various petrophysical parameters of coal may have different influences on the sorption properties of coal, and the impact of one of the parameters may limit the influence of another [25].…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2020

View full text Add to dashboard Cite

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.

show abstract

Section: Introductionmentioning

confidence: 99%

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

et al. 2020

View full text Add to dashboard Cite

show abstract

“…The value was obtained under white light, using a luminometer system to magnify the polished coal 500 times in an oil immersion apparatus, and then perform petrological observation (500 points) according to the Chinese (GB/T) 6948-1998 experimental standard [17]. Proximate analysis of coal samples, with a particle size of less than 0.2 mm, according to the ISO 17246-2010 experimental standard, including the Ash content of the air drying base (A ad ), Volatile content of the air drying base (V ad ), Moisture content of the air drying base (M ad ) and the Organic carbon content of the air drying base (FC ad ) as our previous research [18].…”

Section: Coal Basic Analysismentioning

confidence: 99%

“…The volatile content of coal refers to the amount of gas that is decomposed and escaped from the coal under high temperature, which is an important indicator for evaluating the coalification [18]. There is a strong index correlation between the volatile content and R o,m ; that is, the volatile content decreases with the increase of R o,m (Figure 3a).…”

Section: R Om and Proximate Analysismentioning

confidence: 99%

Methane Adsorption Interpreting with Adsorption Potential and Its Controlling Factors in Various Rank Coals

et al. 2020

Self Cite

View full text Add to dashboard Cite

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.

show abstract

“…The southern part of the Qinshui Basin is one of the earliest areas for CBM exploration and development in China, and it has also attracted the most investment and research in CBM exploration and development in China [47]. The CBM storage conditions in this area are stable and have good development potential [48,49].…”

Section: Case Studymentioning

confidence: 99%

A Risk Assessment Model of Coalbed Methane Development Based on the Matter-Element Extension Method

et al. 2019

View full text Add to dashboard Cite

Coalbed methane development represents a complex system engineering operation that involves complex technology, many links, long cycles, and various risks. If risks are not controlled in a timely and effective manner, project operators may easily cause different levels of casualties, resource waste and property loss. To evaluate the risk status of coalbed methane development projects, this paper constructs a coalbed methane development risk assessment index system that consists of six first grade indexes and 45 second grade indexes. The weight of each index is calculated based on the structure entropy weight method. Then, a theoretical model for risk assessments of coalbed methane development is established based on the matter-element extension method. Finally, the model is applied to analyze a coalbed methane development project in the southern Qinshui Basin of China. The results show that the overall risk level of the coalbed methane development project is Grade II, indicating that the overall risk of the project is small, but the local risk of the project needs to be rectified in time. The assessment results are consistent with the actual operation of the project, indicating that the established risk assessment model has good applicability and effectiveness.

show abstract

Variation of Petrophysical Properties and Adsorption Capacity in Different Rank Coals: An Experimental Study of Coals from the Junggar, Ordos and Qinshui Basins in China

Cited by 24 publications

References 36 publications

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

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

Methane Adsorption Interpreting with Adsorption Potential and Its Controlling Factors in Various Rank Coals

A Risk Assessment Model of Coalbed Methane Development Based on the Matter-Element Extension Method

Contact Info

Product

Resources

About