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

Journal Article · · Langmuir
DOI:https://doi.org/10.1021/la060898r· OSTI ID:20823932
; ;  [1]
  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, Vol. 22, Issue 23; ISSN 0743-7463
Country of Publication:
United States
Language:
English