Dynamic Micromapping of CO2 Sorption in Coal

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• 作者：Andrzej P. Radliski ; Tara L. Busbridge ; Evan MacA. Gray ; Tomasz P. Blach ; Gang Cheng ; Yuri B. Melnichenko ; David J. Cookson ; Maria Mastalerz ; Joan Esterle
• 刊名：Langmuir
• 出版年：2009
• 出版时间：February 17, 2009
• 年：2009
• 卷：25
• 期：4
• 页码：2385-2389
• 全文大小：189K
• 年卷期：v.25,no.4(February 17, 2009)
• ISSN：1520-5827

文摘

We have applied X-ray and neutron small-angle scattering techniques (SAXS, SANS, and USANS) to study the interaction between fluids and porous media in the particular case of subcritical CO₂ sorption in coal. These techniques are demonstrated to give unique, pore-size-specific insights into the kinetics of CO₂ sorption in a wide range of coal pores (nano to meso) and to provide data that may be used to determine the density of the sorbed CO₂. We observed densification of the adsorbed CO₂ by a factor up to five compared to the free fluid at the same (p, T) conditions. Our results indicate that details of CO₂ sorption into coal pores differ greatly between different coals and depend on the amount of mineral matter dispersed in the coal matrix: a purely organic matrix absorbs more CO₂ per unit volume than one containing mineral matter, but mineral matter markedly accelerates the sorption kinetics. Small pores are filled preferentially by the invading CO₂ fluid and the apparent diffusion coefficients have been estimated to vary in the range from 5 × 10⁻⁷ cm²/min to more than 10⁻⁴ cm²/min, depending on the CO₂ pressure and location on the sample.