Study of high-pressure sorption of methane on Chinese coals of different rank

Shen, Jian, Qin, Yong, Fu, Xuehai, Wang, Geoff, Chen, Run and Zhao, Lijuan (2014) Study of high-pressure sorption of methane on Chinese coals of different rank. Arabian Journal of Geosciences, 8 6: 3451-3460. doi:10.1007/s12517-014-1459-y


Author Shen, Jian
Qin, Yong
Fu, Xuehai
Wang, Geoff
Chen, Run
Zhao, Lijuan
Title Study of high-pressure sorption of methane on Chinese coals of different rank
Journal name Arabian Journal of Geosciences   Check publisher's open access policy
ISSN 1866-7511
1866-7538
Publication date 2014-05-31
Year available 2014
Sub-type Article (original research)
DOI 10.1007/s12517-014-1459-y
Open Access Status Not yet assessed
Volume 8
Issue 6
Start page 3451
End page 3460
Total pages 10
Place of publication Heidelberg, Germany
Publisher Springer
Language eng
Subject 2300 Environmental Science
1900 Earth and Planetary Sciences
Abstract To investigate the sorption and diffusion behavior of deep coals, high-pressure sorption experiments of methane on coals were performed by the volumetric method. The experimental sorption isotherms fit the Langmuir model over the experimental pressure and temperature ranges. The sorption volumes of all coals tested exhibit a typical temperature behavior with a negative exponent decreasing as temperature increases. An approximately linear correlation for the methane Langmuir volume with coal rank was observed. The effect of coal rank on adsorption volume decreases with increasing temperature. The Langmuir pressure decreases initially with coal rank, reaches a minimum pressure corresponding to the maximum vitrinite reflectance at ∼2.2 % and then increases. Studies on the diffusion of methane in coal using a unipore diffusion model showed that the effective diffusion coefficients for the seven coals studied varied from 2.98 to 68.3 × 10 s. The effective diffusion coefficients of coal at the first pressure step generally increased linearly with increasing temperature, and a complex nonlinear relationship for methane sorption rate with coal rank was observed. Finally, an empirical equation was developed to estimate the sorption capacity of methane on coal of a given rank as a function of the coal burial depth in a time-invariant pressure and temperature field. The sorption capacity of the moisture-equilibrated coal was found to increase with burial depth until it reaches a maximum of 24 cm/g at ∼1,500 m, followed by a slow decline to 20.5 cm/g at approximately 3,000 m.
Formatted abstract
To investigate the sorption and diffusion behavior of deep coals, high-pressure sorption experiments of methane on coals were performed by the volumetric method. The experimental sorption isotherms fit the Langmuir model over the experimental pressure and temperature ranges. The sorption volumes of all coals tested exhibit a typical temperature behavior with a negative exponent decreasing as temperature increases. An approximately linear correlation for the methane Langmuir volume with coal rank was observed. The effect of coal rank on adsorption volume decreases with increasing temperature. The Langmuir pressure decreases initially with coal rank, reaches a minimum pressure corresponding to the maximum vitrinite reflectance at ∼2.2 % and then increases. Studies on the diffusion of methane in coal using a unipore diffusion model showed that the effective diffusion coefficients for the seven coals studied varied from 2.98 to 68.3 × 10-5 s-1. The effective diffusion coefficients of coal at the first pressure step generally increased linearly with increasing temperature, and a complex nonlinear relationship for methane sorption rate with coal rank was observed. Finally, an empirical equation was developed to estimate the sorption capacity of methane on coal of a given rank as a function of the coal burial depth in a time-invariant pressure and temperature field. The sorption capacity of the moisture-equilibrated coal was found to increase with burial depth until it reaches a maximum of 24 cm3/g at ∼1,500 m, followed by a slow decline to 20.5 cm3/g at approximately 3,000 m.
Keyword Chinese coal
Coalbed methane
High-pressure sorption
Diffusion
Sorption kinetics
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: School of Chemical Engineering Publications
Official 2015 Collection
 
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