Nuclear magnetic resonance study on the influence of liquid nitrogen cold soaking on the pore structure of different coals

Liu, Shumin; Sun, Haitao; Zhang, Dongming; Yang, Kun; Wang, Dengke; Li, Xuelong; Long, Kun; Li, Yaning

doi:10.1063/5.0135290

Cited by 70 publications

(40 citation statements)

References 55 publications

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“…The O–H in ST coal with 5.30% oxygen content forms a small amount of hydrogen bonds. The oxygen content of NM coal is the best, and its infrared spectrum has the largest stretching vibration peak of hydrogen bond O–H, which moves to about 3400 cm –1 in the low-frequency direction, and the right side of the peak overlaps with the stretching vibration peak of the aromatic C–H bond. − …”

Section: Results and Discussionmentioning

confidence: 99%

Infrared Spectrum Characteristics and Quantification of OH Groups in Coal

et al. 2023

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The KBr pellet press method for detecting the infrared spectrum of coal is one of the commonly used methods for analyzing the types and content of functional groups in coal. However, KBr crystalline water or moisture has a significant impact on the peak position, peak shape, and peak area of the organic O–H based stretching vibration wave in coal. In this paper, the theoretical characteristics of infrared spectra of phenols and alcohols have been simulated and analyzed using the Gaussian 16 series of programs. Four infrared spectral analysis techniques, in situ infrared, KBr pellet press, dry KBr pellet press, and paste methods, have been used to detect the infrared spectra of coal. The results show that the stretching vibration peaks of free O–H radicals without hydrogen bonding are located between 3700 and 3600 cm–1. After the O–H form hydrogen bonds with each other, the O–H stretching vibration frequency moves toward the low frequency direction, and the lower the wavenumber, the more O–H content. The conventional KBr gasket manufacturing process will absorb moisture in the air to interfere with the hydroxyl absorption peak of coal, and the experimental process requires absolute drying. The relative content of hydroxyl in coal can be compared and analyzed based on the peak position, peak shape, and peak area of the hydroxyl stretching vibration wave. Quantitative analysis of hydroxyl groups in coal also requires combination of elemental analysis and X-ray photoelectron spectroscopy.

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Section: Results and Discussionmentioning

confidence: 99%

Infrared Spectrum Characteristics and Quantification of OH Groups in Coal

et al. 2023

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“…When the pressure is higher, the adsorption capacity of coal with small particle size exceeds that of coal with large particle size. Under the action of low pressure, the coal molecules with small particle size are more closely arranged, , and the gas molecules are subjected to too small force to adsorb to the surface of coal, so the adsorption capacity is smaller than that of coal with large particle size at low pressure.…”

Section: Resultsmentioning

confidence: 99%

Experimental Study on Influencing Factors and Thermal Effects of CO₂ Adsorption by Coal

et al. 2023

ACS Omega

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The utilization of CO2 is extremely important to solve the environmental problems and coal spontaneous combustion in goaf. There are three kinds of CO2 utilization in goaf: adsorption, diffusion, and seepage. Since adsorption will consume CO2 in goaf, the optimization of CO2 injection amount is very critical. A self-developed adsorption experimental device was used to determine the CO2 adsorption capacity of three different particle sizes of lignite coal samples at 30–60 °C and 0.1–0.7 MPa. The factors affecting CO2 adsorption by coal and its thermal effect were studied. In the coal and CO2 system, the CO2 adsorption characteristic curve is not affected by temperature, but there are differences in that with different particle sizes. The adsorption capacity increases with the increase of pressure, while it decreases with the increase of temperature and particle size. Under atmospheric pressure, the adsorption capacity of coal is a logistic function relationship with temperature. Furthermore, the average adsorption heat of CO2 on lignite shows that the interaction force between CO2 molecules has a stronger effect on CO2 adsorption than the effect of heterogeneity and anisotropy on the coal surface. Finally, the existing gas injection equation is improved theoretically with CO2 dissipation, which provides a new idea for the work of CO2 prevention and fire suppression in goaf.

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“…The deformation characteristics and mechanism of the coal body will be affected by the external pressure, and the temperature at the time of tectonic deformation and coalification degree. Therefore, in this study, three groups of factors, namely, the ground stress, gas pressure, and coal firmness coefficient, were selected, which had a significant influence on coal body deformation . The three groups of influencing factors under the action of cumulative blasting were separately and comprehensively analyzed by the orthogonal design method to determine the influence of different influencing factors on the fracture radius of cumulative blasting, and the parameter equation for predicting the fracture radius of cumulative blasting was obtained …”

Section: Theory and Methodsmentioning

confidence: 99%

Prediction of the Penetration Radius of Cumulative Blasting

Jia

Zhao³

et al. 2023

ACS Omega

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To improve the efficiency of coal seam gas extraction, the influence characteristics of different factors on the penetration effect of cumulative blasting were determined and the hole spacing was effectively predicted; in this work, we used ANSYS/LS-DYNA numerical simulation software to establish the penetration model of cumulative blasting. Combined with an orthogonal design scheme, the crack radius prediction of cumulative blasting was studied. A prediction model for predicting the fracture radius of cumulative blasting based on three groups of different factors was established. The results showed that the primary and secondary order of factors that affected the fracture radius of cumulative blasting was as follows: ground stress > gas pressure > coal firmness coefficient. The penetration effect decreased with increasing ground stress and decreased with an increase in the gas pressure and coal firmness coefficient. The industrial field test was carried out. The gas extraction concentration increased by 73.4% after cumulative blasting, and the effective crack radius of cumulative blasting was approximately 5.5−6 m. The maximum error of the numerical simulation was 1.2%, and the maximum error of the industrial field test was 6.22%, which proved that the crack radius prediction model of cumulative blasting was correct.

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Nuclear magnetic resonance study on the influence of liquid nitrogen cold soaking on the pore structure of different coals

Cited by 70 publications

References 55 publications

Infrared Spectrum Characteristics and Quantification of OH Groups in Coal

Infrared Spectrum Characteristics and Quantification of OH Groups in Coal

Experimental Study on Influencing Factors and Thermal Effects of CO₂ Adsorption by Coal

Prediction of the Penetration Radius of Cumulative Blasting

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Nuclear magnetic resonance study on the influence of liquid nitrogen cold soaking on the pore structure of different coals

Cited by 70 publications

References 55 publications

Infrared Spectrum Characteristics and Quantification of OH Groups in Coal

Infrared Spectrum Characteristics and Quantification of OH Groups in Coal

Experimental Study on Influencing Factors and Thermal Effects of CO2 Adsorption by Coal

Prediction of the Penetration Radius of Cumulative Blasting

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Product

Resources

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Experimental Study on Influencing Factors and Thermal Effects of CO₂ Adsorption by Coal