As part of the efforts to model enhanced coalbed methane recovery and CO2 sequestration in coalbeds, the pure adsorption isotherm behavior of five dry coals, i.e., Illinois No. 6, Wyodak sub-bituminous, Pocahontas, Beulah Zap, and Upper Freeport coal was studied. Using a volumetric technique, isotherms of pure CH4, N2, CO2, and ethane were measured at 328.15 K and 13.8 MPa. The average expected experimental uncertainties of the pure-gas adsorption data was ∼ 7%. Uncertainties were smallest for nitrogen and largest for ethane. At low pressures, an amount of adsorbed gas increased in the order: N2, CH4, C2H6, and CO2. C2H6 isotherms had excess adsorption maximums between 4 to 6 MPa and CO2 isotherms had excess adsorption maximums between 6 to 8.5 MPa. The excess adsorption isotherm of CH4 on Upper Freeport and Pocahontas was flat at > 10 MPa. CH4 and N2 showed far less variation in adsorption amounts than either CO2 or ethane. The ratio of CO2 to ethane adsorption varied among the coals. Little variation in isotherm reproducibility was shown for methane after the coal was subjected to CO2 and ethane gas adsorption. The Ono-Kondo model was capable of representing precisely each isotherm within the experimental uncertainties. This is an abstract of a paper presented at the AIChE 2004 Annual Meeting (Austin, TX 11/7-12/2004).
|Publication status||Published - 1 Dec 2004|
|Event||2004 AIChE Annual Meeting - Austin, TX, United States|
Duration: 7 Nov 2004 → 12 Nov 2004
|Conference||2004 AIChE Annual Meeting|
|Period||7/11/04 → 12/11/04|