Original Articles: 2011 Vol: 3 Issue: 2
Analysis of adsorption compression for CH4/CO2 mixture in supercritical systems
Abstract
The Ono-Kondo model is used to correlate with experimental data from references for the
adsorption of methane and carbon dioxide binary mixture on activated carbon Filtrasorb 400 at
318 K and on Norit R1 Extra at 298 K. CH4-CH4 interaction in adsorbed layer can be analyzed
by using coordinates of equation (4) while CO2-CO2 interaction can be evaluated by using
coordinates of equation (5). The energy of adsorbate-adsorbate interactions (between a central
molecule and surrounding molecules in the adsorbed phase) varies from positive at low
pressures to negative at high pressure ends. This result indicates phenomenon of adsorption
compression with repulsive interactions in adsorbed phase. The shape of isotherms in
Ono-Kondo coordinates can be interpreted in terms of adsorbate-adsorbate interactions: the
slope versus density represents potential function where the distance between nearest neighbors
is a function of adsorbate density. This transition indicates the competitive nature of the
individual component adsorption from the mixtures. CO2 is most adsorbed component. Even if
the concentration of CO2 in the bulk is lowered, the adsorption competitive stays in favor of CO2