Real-time pore structure evolution difference between deep and shallow coal during gas adsorption: A study based on synchrotron radiation small-angle X-ray scattering--颗粒学报PARTICUOLOGY

Sun, Y., Zhu, S., Xie, F., Han, C., Zhao, Y., & Zhang, Z. (2024). Real-time pore structure evolution difference between deep and shallow coal during gas adsorption: A study based on synchrotron radiation small-angle X-ray scattering. Particuology, 87, 114-123. https://doi.org/10.1016/j.partic.2023.08.002

Real-time pore structure evolution difference between deep and shallow coal during gas adsorption: A study based on synchrotron radiation small-angle X-ray scattering

Yingfeng Sun ^{a b *}, Shuaipeng Zhu ^b, Fei Xie ^c, Chujian Han ^{d e}, Yixin Zhao ^d^e, Zetian Zhang ^f

a Research Institute of Macro-Safety Science, University of Science and Technology Beijing, Beijing, 100083, China
b School of Civil and Resource Engineering, University of Science and Technology Beijing, Beijing, 100083, China
c National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, 230029, China
d Beijing Key Laboratory for Precise Mining of Intergrown Energy and Resources, China University of Mining and Technology (Beijing), Beijing, 100083, China
e School of Energy and Mining Engineering, China University of Mining and Technology (Beijing), Beijing, 100083, China
f Key Laboratory of Deep Earth Science and Engineering (Sichuan University), Ministry of Education, Chengdu, 610065, China

10.1016/j.partic.2023.08.002

Volume 87, April 2024, Pages 114-123

Received 18 May 2023, Revised 26 July 2023, Accepted 5 August 2023, Available online 24 August 2023, Version of Record 30 August 2023.

E-mail: yingfengsun@ustb.edu.cn

Highlights

• Synchrotron radiation small-angle X-ray scattering was adopted for the real-time coal pore evolution characterization.

• Impact of coal compositions and stress history on pore structure evolution was comprehensively analyzed.

• Pore structure evolution difference between deep and shallow coal during gas adsorption was investigated.

Abstract

Coal seam CO₂ sequestration is an important option to address global warming. A better knowledge on coal pore structure evolution during gas adsorption can provide guidance for coal seams CO₂ sequestration. However, few investigations on the pore structure evolution differences between the deep and shallow coal were conducted during gas adsorption. In this study, based on the real-time synchrotron radiation small-angle X-ray scattering (SAXS) observation, the average pore diameter and pore surface fractal dimension evolution differences between deep and shallow coal were investigated from the aspects of coal compositions and stress history. Two types of coal deformation (inner-swelling and outer-swelling) coexist during gas adsorption. Coal compositions have significant impact on the dominance of deformation type. The dominance of inner-swelling in deep coal is induced by the higher ash contents, and there is the decrease of average pore diameter during gas adsorption. The impact of stress-history (burial depth) on adsorption-induced deformation is more prominent than that of gas adsorption capacity. In deep coal, the surface fractal dimension evolution presents a negative correlation with the evolution of pore diameters. In shallow coal, the surface fractal dimension evolution presents a Langmuir-type correlation with the adsorption time.

Graphical abstract

Keywords

Coal; Gas adsorption; Synchrotron radiation small-angle X-ray scattering; Pore diameter; Surface fractal dimension

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