Authors: Carlos A. Grande, Richard Blom, Andreas Möller, Jens Möllmer
Journal: Chemical Engineering Science 89 (2013) 10–20, DOI:10.1016/j.ces.2012.11.024

Activated carbon was evaluated as selective adsorbent for separation of CO2 from CO2/CH4 mixtures with special focus on high pressure applications. Binary adsorption equilibrium measurements and binary breakthrough curves with mixtures of 10 and 20% CO2 balanced with CH4 were carried out at three different pressures: 500, 2500 and 5000 kPa. A 1D mathematical model including mass, energy and momentum transport was used to describe the curves using a non-ideal gas behavior equation. CO2 is more selectively adsorbed than CH4 in the activated carbon used in this study. The binary adsorption capacity obtained from binary breakthrough curves could only be well described by the Sips model. In all breakthrough curves, a small effect of the film mass transfer could be observed, particularly at higher pressures where this effect is more pronounced. The significant adsorption of CH4 may limit the application of this adsorbent for natural gas upgrading.