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Gas diffusion in coal powders is a multi-rate process

Mathias, Simon; Dentz, Marco; Liu, Qingquan

Gas diffusion in coal powders is a multi-rate process Thumbnail


Marco Dentz

Qingquan Liu


Gas migration in coal is strongly controlled by surface diffusion of adsorbed gas within the coal matrix. Surface diffusion coefficients are obtained by inverse modelling of transient gas desorption data from powdered coals. The diffusion coefficient is frequently considered to be dependent on time and initial pressure. In this article, it is shown that the pressure dependence can be eliminated by performing a joint inversion of both the diffusion coefficient and adsorption isotherm. A study of the log–log slope of desorbed gas production rate against time reveals that diffusion within the individual coal particles is a multi-rate process. The application of a power-law probability density function of diffusion rates enables the determination of a single gas diffusion coefficient that is constant in both time and initial pressure.


Mathias, S., Dentz, M., & Liu, Q. (2020). Gas diffusion in coal powders is a multi-rate process. Transport in Porous Media, 131, 1037-1051.

Journal Article Type Article
Acceptance Date Dec 2, 2019
Online Publication Date Dec 10, 2019
Publication Date 2020
Deposit Date Dec 3, 2019
Publicly Available Date Dec 10, 2020
Journal Transport in Porous Media
Print ISSN 0169-3913
Electronic ISSN 1573-1634
Publisher Springer
Peer Reviewed Peer Reviewed
Volume 131
Pages 1037-1051


Accepted Journal Article (560 Kb)

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