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Impact of coal composition and pore structure on gas adsorption: a study based on a synchrotron radiation facility
Author(s) -
Sun Yingfeng,
Zhao Yixin,
Yuan Liang
Publication year - 2020
Publication title -
greenhouse gases: science and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.45
H-Index - 32
ISSN - 2152-3878
DOI - 10.1002/ghg.1935
Subject(s) - adsorption , coalbed methane , coal , fractal dimension , small angle x ray scattering , desorption , porosity , nanopore , chemical engineering , materials science , specific surface area , mineralogy , langmuir , chemistry , fractal , scattering , composite material , nanotechnology , coal mining , organic chemistry , optics , mathematical analysis , physics , mathematics , engineering , catalysis
A better knowledge about the impact of coal composition and pore structure on gas adsorption is of great significance for coalbed methane exploration and uneconomic coalbed CO 2 storage. Coal is a porous medium with complex organic components, and most pores in coal are nanopores that have a complex geometrical morphology. As a result, it is significantly necessary to investigate the impact of coal composition and pore structure on gas adsorption based on coal 3D nanopore structure. Synchrotron radiation nano‐computed tomography (CT) was applied to acquire 3D coal nanopore structure and synchrotron radiation small‐angle X‐ray scattering (SAXS) was used to obtain the pore surface fractal dimension. The coal with higher pore surface fractal dimension presents higher Langmuir volume. Based on the 3D nanopore structure acquired by synchrotron radiation nano‐CT, gas adsorption capacity was characterized by the adsorbed gas amount on unit pore surface area. It was found that gas adsorption capacity depends on the coal composition. There is a negative correlation between gas adsorption capacity and ash content and oxygen‐containing groups, and a positive correlation between gas adsorption capacity and vitrinite contents. Hysteresis between desorption and adsorption isotherms is dependent upon the ratio of throat number to pore number, and the hysteresis becomes more significant when the ratio is larger. © 2019 Society of Chemical Industry and John Wiley & Sons, Ltd.