Modeling high-pressure adsorption of gas mixtures on activated carbon and coal using a simplified local-density model

Journal Article · Tue Nov 07 04:00:00 EST 2006 · Langmuir

DOI:https://doi.org/10.1021/la060898r· OSTI ID:20823932

Fitzgerald, J E; Robinson, R L; Gasem, K A.M. ^[1]

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1. Oklahoma State University, Stillwater, OK (United States). School of Chemical Engineering

The simplified local-density (SLD) theory was investigated regarding its ability to provide accurate representations and predictions of high-pressure supercritical adsorption isotherms encountered in coalbed methane (CBM) recovery and CO{sub 2} sequestration. Attention was focused on the ability of the SLD theory to predict mixed-gas adsorption solely on the basis of information from pure gas isotherms using a modified Peng-Robinson (PR) equation of state (EOS). An extensive set of high-pressure adsorption measurements was used in this evaluation. These measurements included pure and binary mixture adsorption measurements for several gas compositions up to 14 MPa for Calgon F-400 activated carbon and three water-moistened coals. Also included were ternary measurements for the activated carbon and one coal. For the adsorption of methane, nitrogen, and CO{sub 2} on dry activated carbon, the SLD-PR can predict the component mixture adsorption within about 2.2 times the experimental uncertainty on average solely on the basis of pure-component adsorption isotherms. For the adsorption of methane, nitrogen, and CO{sub 2} on two of the three wet coals, the SLD-PR model can predict the component adsorption within the experimental uncertainties on average for all feed fractions (nominally molar compositions of 20/80, 40/60, 60/40, and 80/20) of the three binary gas mixture combinations, although predictions for some specific feed fractions are outside of their experimental uncertainties.

• OSTI ID: 20823932
• Journal Information: Langmuir, Journal Name: Langmuir Journal Issue: 23 Vol. 22; ISSN LANGD5; ISSN 0743-7463
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
ACTIVATED CARBON
ADSORPTION
ADSORPTION ISOTHERMS
CARBON DIOXIDE
CARBON SEQUESTRATION
COAL
COAL SEAMS
EQUATIONS
EQUATIONS OF STATE
MATHEMATICAL MODELS
METHANE
MIXTURES
NITROGEN
PRESSURE RANGE MEGA PA 01-10
PRESSURE RANGE MEGA PA 10-100
SORPTIVE PROPERTIES
SUPERCRITICAL STATE