scholarly journals Pore characterization of different types of coal from coal and gas outburst disaster sites using low temperature nitrogen adsorption approach

2017 ◽  
Vol 27 (2) ◽  
pp. 371-377 ◽  
Author(s):  
Lingling Qi ◽  
Xu Tang ◽  
Zhaofeng Wang ◽  
Xinshan Peng
Keyword(s):  
Low Temperature ◽  
Nitrogen Adsorption ◽  
Coal And Gas Outburst ◽  
Gas Outburst ◽  
Pore Characterization ◽  
Different Types

Research on the Differences of the Pore Characteristics with Different Destroyed-Type Coals

2012 ◽  
Vol 619 ◽  
pp. 598-602 ◽  
Author(s):  
Ling Ling Qi ◽  
Zhao Feng Wang ◽  
Hong Min Yang
Keyword(s):  
Low Temperature ◽  
Pressure Range ◽  
Size Range ◽  
Nitrogen Adsorption ◽  
Coal And Gas Outburst ◽  
Relative Pressure ◽  
Pore Characteristics ◽  
Gas Outburst ◽  
Adsorption Curve ◽  
Closed Pore

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.

Monte Carlo simulation and experimental studies on the low temperature characterization of nitrogen adsorption on graphite

Carbon ◽  
2013 ◽  
Vol 52 ◽  
pp. 158-170 ◽  
Author(s):  
Chunyan Fan ◽  
D.D. Do ◽  
D. Nicholson ◽  
Jacek Jagiello ◽  
Jeffrey Kenvin ◽  
...  
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Low Temperature ◽  
Experimental Studies ◽  
Nitrogen Adsorption

scholarly journals Characterization of Carbon Beads Derived from Porous Polyimide Copolymer

1997 ◽  
Vol 15 (6) ◽  
pp. 437-444 ◽  
Author(s):  
T. Matynia ◽  
B. Gawdzik ◽  
P. Staszczuk
Keyword(s):  
Low Temperature ◽  
Porous Carbon ◽  
Chemical Structure ◽  
Mercury Porosimetry ◽  
Nitrogen Adsorption ◽  
Carbon Sorbent ◽  
Carbon Particles ◽  
Isothermal Analysis ◽  
Porous Copolymer

A new carbon sorbent obtained by the carbonization of beads of the porous copolymer of 4,4′-bis(maleimidodiphenyl)methane and styrene is described. To determine the influence of the carbonization process on the porous and chemical structure of the sorbent, nitrogen adsorption at low temperature, mercury porosimetry, quasi-isothermal analysis and chromatographic measurements were made. The results indicate that polar imide functional groups were destroyed during carbonization, changing the chemical and porous structure of the sorbent. In consequence, non-polar porous carbon particles were obtained.

scholarly journals Characterization of Pores and Fractures in Soft Coal from the No. 5 Soft Coalbed in the Chenghe Mining Area

Processes ◽  
2018 ◽  
Vol 7 (1) ◽  
pp. 13 ◽  
Author(s):  
Pan Wei ◽  
Yunpei Liang ◽  
Song Zhao ◽  
Shoujian Peng ◽  
Xuelong Li ◽  
...  
Keyword(s):  
Low Temperature ◽  
Pore Structure ◽  
Pore Volume ◽  
Fractal Dimensions ◽  
Nitrogen Adsorption ◽  
Mining Area ◽  
Hard Coal ◽  
Structure Characteristics ◽  
Soft Coal

The characteristics of the pore structure and gas migration in soft coalbeds are the premise of evaluating gas discharge in soft coalbeds. To explore the pore structure characteristics of soft coal masses, the No. 5 soft coalbed in the eastern zone of Chenghe Mining Area, was investigated and compared with the No. 5 hard coalbed in the western zone. By using a mercury intrusion method, low-temperature liquid nitrogen adsorption, and scanning electron microscopy (SEM), the pore structure characteristics of the No. 5 coalbed were explored. Moreover, based on fractal theory, the pore structure of coal was characterized. The results showed the pores in soft coal mainly appeared as small pores and micropores in which the small pores accounted for nearly half of the total pore volume. Mesopores and macropores were also distributed throughout the soft coal. The mercury-injection and mercury-ejection curves of soft coal showed significant hysteresis loops, implying that pores in coal samples were mainly open while the mercury-injection curve of hard coal was consistent with its mercury-ejection curve, showing no hysteresis loop while having an even segment, which indicated that closed pores occupied the majority of the pore volume in the coal samples. The curves of low-temperature nitrogen adsorption of soft coal all follow an IV-class isotherm. Moreover, the fractal dimensions of soft coal are respectively larger than the fractal dimensions of hard coal. It can be seen that the characterization of pores and fractures of the soft coal was different from the hard coal in the western distinct of the old mining area. The gas prevention and control measures of soft coal should be formulated according to local conditions.

scholarly journals The Characteristics of Closed Pores in Coals With Different Ranks

2021 ◽  
Vol 9 ◽  
Author(s):  
Tong Liu ◽  
Yixin Zhao ◽  
Nima Noraei Danesh
Keyword(s):  
Molecular Structure ◽  
Coalbed Methane ◽  
Analytical Techniques ◽  
Nitrogen Adsorption ◽  
Coal And Gas Outburst ◽  
Aromatic Rings ◽  
Closed Porosity ◽  
Gas Outburst ◽  
X Ray Scattering ◽  
High Degree

The closed pores in coal seams influence the storage of coalbed methane. The investigation of closed pores characteristics for coals is of great significance in improving the production of coalbed methane and revealing the mechanism of coal and gas outburst. However, due to limitations in analytical techniques, the characteristics and evolution mechanism of closed pores in coals with different ranks are not sufficiently understood. In this paper, eight coal samples with different ranks were collected and characterized by small-angle X-ray scattering (SAXS) and low-temperature nitrogen adsorption (LTNA). The open and closed pores of coals with various ranks were studied, and the mechanism for evolution of closed pores during coalification was proposed. The results show that among eight coal samples with different ranks, the closed porosity of low-metamorphic coals is relatively lower, the closed porosity of medium-metamorphic coals is in the middle, and the closed porosity of high-metamorphic coals is relatively higher. The change in closed porosity for coals with different ranks may be related to varieties of the molecular structure of coals. The low-metamorphic coals have more disordered arrangement of molecular structure and easily form connected pores. Therefore, the closed porosity in low-metamorphic coals is low. The aromatization of medium-metamorphic coals turns aliphatic chains into closed aromatic rings, and the closed porosity of these coals also increases. When coals reach a high degree of metamorphism, polycondensation compacts the coal macromolecular structure, providing for easy formation of closed pores between aromatic condensed rings, so the closed porosity is obviously increased in high-metamorphic coals. This study has dual significance in advancing the understanding of open and closed pores in coals and the mechanism of coal and gas outburst.

scholarly journals Pore Structure of Coals by Mercury Intrusion, N2 Adsorption and NMR: A Comparative Study

2019 ◽  
Vol 9 (8) ◽  
pp. 1680 ◽  
Author(s):  
Zhu ◽  
Yang ◽  
Lu ◽  
Liu ◽  
Li ◽  
...  
Keyword(s):  
Pore Size ◽  
Coalbed Methane ◽  
Early Stage ◽  
Total Porosity ◽  
Nitrogen Adsorption ◽  
Mercury Intrusion ◽  
Low Field ◽  
Pore Characterization ◽  
Nuclear Magnetic

Coalbed methane (CBM) mainly adsorb in massive pores of coal. The accurate characterization of pores benefits CBM resource evaluation, exploration and exploitation. In this paper, mercury intrusion porosimetry (MIP) and low temperature nitrogen adsorption (N2GA) combined with low field nuclear magnetic resonance (NMR) experiments were conducted to analyze the advantages and differences among different experimental techniques in pore characterization. The results show that the total porosity has a tendency to decrease first and then rise with the increase of coal rank, which is mainly caused by the compaction in early stage and the thermogenic gas produced in middle and late stages of coalification. The comparison between different techniques shows that NMR is superior to the conventional methods in terms of porosity and pore size distribution, which should be favorable for pore characterization. The N2GA pore size measurement, based on BJH model, is only accurate within 10‒100 nm in diameter. There is a peak misalignment between the NMR and MIP results in the pore size comparison. The reason for this phenomenon is that there is a centrifugal error in NMR experiment, which could cause a differential damage to the coal sample, resulting in partial loss of the nuclear magnetic signal.

scholarly journals Problems in the Classification of Mine Gas Grades and Classification of Coal and Gas Outburst Mine Types

CONVERTER ◽  
2021 ◽  
pp. 426-431
Author(s):  
Xianzhi Shi, Et al.
Keyword(s):  
Coal And Gas Outburst ◽  
Control Measures ◽  
Gas Content ◽  
Gas Outburst ◽  
Storage Media ◽  
Coal Mine Gas ◽  
Different Types ◽  
Mine Gas ◽  
Disaster Control

Since the classification of coal mine gas grade, there has been a classification mode with inconsistent classification basis and progressive relationship between gas mine and coal and gas outburst mine. This paper demonstrates the irrationality of the progressive relationship between coal and gas outburst mines and gas mines from the aspects of different classification materials, inconsistent gas storage media and different disaster control measures, and determines that coal and gas outburst mines and gas mines coexist and are different types of mines. According to the actual amount of outburst coal, the outburst mines are divided into weak, medium, strong and extremely strong outburst mines by using gas content W, coal seam firmness coefficient f and gas pressure P.

Sign in / Sign up

Export Citation Format

Share Document