Inter-laboratory comparison II: CO2 isotherms measured on moisture-equilibrated Argonne premium coals at 55 °C and up to 15 MPa

Sorption isotherms, which describe the coal's gas storage capacity, are important for estimating the carbon sequestration potential of coal seams. This study investigated the inter-laboratory reproducibility of carbon dioxide isotherm measurements on moisture-equilibrated Argonne premium coal samples (Pocahontas No. 3, Illinois No. 6, and Beulah Zap). Six independent laboratories provided isotherm data on the three moisture-equilibrated coal samples at 55 °C and pressures up to 15 MPa. Agreement among the laboratories was good up to 8 MPa. At the higher pressures, the data among the laboratories diverged significantly for two of the laboratories and coincided reasonably well for four of the laboratories.