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On the porous structure of coals: Evidence for an interconnected but constricted micropore system and implications for coalbed methane recovery (1997)

Radovic, L. R. ; Menon, V. C. ; Leon Y Leon, C. A. ; [et al.]

Springer

Adsorption 3 (1997), S. 221-232

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ISSN: 1572-8757

Keywords: coalbed methane ; coal (porous structure, micropores) ; adsorption (of xenon, carbon dioxide, methane) ; Xe-129 NMR spectroscopy

Source: Springer Online Journal Archives 1860-2000

Topics: Chemistry and Pharmacology , Physics , Process Engineering, Biotechnology, Nutrition Technology

Notes: Abstract An experimental and theoretical study of adsorption and diffusion of carbon dioxide and methane in coals of widely varying rank was carried out. Low pressures adsorption isotherms of CO2 were obtained and analyzed using Dubinin's theory of volume filling of micropores. High-pressure adsorption isotherms of CH4 were obtained and analyzed using tracer pulse chromatography in conjunction with an appropriate adsorption/diffusion model. A preliminary129Xe NMR analysis of chemical shifts experienced by xenon atoms in particles of different sizes is also reported. The heretofore undocumented and/or underestimated effects of activated diffusion of CO2 at 273–298 K complicate the elucidation of the true microporous structure of coals, especially its dependence on coal rank. Activated diffusion of both CO2 and methane at room temperature does not allow reliable estimates of coalbed gas content to be made. A model of an interconnected network of pores which includes randomly distributed, numerous and ultramicroporous constrictions (at any size scale) is consistent with all these experimental and theoretical findings.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF01650133

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Thermodynamic interactions of solvents with styrene-butadiene-styrene triblock copolymers (1992)

Romdhane, I. Hadj ; Plana, A. ; Hwang, S. ; [et al.]

New York, NY [u.a.] : Wiley-Blackwell

Journal of Applied Polymer Science 45 (1992), S. 2049-2056

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ISSN: 0021-8995

Keywords: Chemistry ; Polymer and Materials Science

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics

Notes: Fundamental thermodynamic interaction data for various solvents with two styrene-butadiene-styrene triblock copolymers (Kraton D-1101 and Kraton D-1300X) have been collected by the use of inverse gas chromatography at infinite dilution. Experimental results are presented for nine D-1101/solvent systems and nine D-1300X/solvent systems at 308, 328. and 348 K. Weight-fraction activity coefficients and Flory-Huggins χ interaction parameters have been calculated from the retention volumes. The χ parameter is used as a measure of the strength of interaction and therefore as a guide in the prediction of polymer-solvent compatibility. In addition, partial molar heats of mixing, ΔHm∞, and heats of solution, ΔHs, were determined. The Hildebrand-Scatchard solubility theory was combined with the Flory theory in order to estimate the solubility parameter of the thermoplastic rubbers at the three different temperatures.

Additional Material: 6 Ill.