Adsorption equilibrium of pure methane and ethane on activated carbon 204-Ⅱ was determined by the volumetric method at 293 K and 0-4 MPa.Adsorption data

with the CH4 concentration in the range of 34.0%-95.2%

were measured by the open flow method on activated carbon 204-Ⅱ at 293 K.The real adsorption solution theory(RAST)expressing the non-ideality of the local adsorbed phase was combined with the micro-pore size distribution(MPSD)model describing the energetic distribution of the adsorbent surface

and a MPSD-RAST model was put forward to predict adsorption equilibrium of binary CH4-C2H6 system.The Wilson equation and the NTRL equation were adopted to calculate activity coefficients for the local adsorbed phase.The ideal adsorption solution theory(IAST)and the MPSD-IAST model were also used for prediction.The investigation demonstrates that the MPSD-RAST model greatly improves prediction accuracy of the adsorption amount and the mole fraction for CH4

compared with the IAST and MPSD-IAST models.For the heavy component C2H6

prediction deviations with these three methods are all lower than 5%.It is important to consider non-ideality of the adsorbed phase in prediction models.