Fitting results comparison of different CHa/ Np adsorption models and its adsorption thermodynamics analysis

in orderto provide the reative adsorption model and thermodynamic data for the separation of CHialNvg in coalbed nethane by pressure swing absoption.the adsorption capaities of CH4 and Ng on the caroon molecular sive(CMS) by sef made at 298.15,313.15 and 328.15 K were measured respectively TheLangnuir model and other eight models were used to ft the experimental data. The fiting degree of these models was compared.Tthe optinizaton volume .ing based model D-A had the best fiting effect while emprical equation Freundich model vas the worst.The fting efect of angmouit Sips and Toh models vere moderte.Th fting de:ree of CH a was beter tnan that of Ny for the same model Meanwile th fitng parameters of diferent models were comparec.the resuls showed that BET model wasuiht o characterze adsopion of CHi; and Nvg on ths CMS. The saturated adsoption capacity qmwas decreased with the inrease of temperature for Langmuir Toth and E-L models.And that change of temperature had greater infuence on Nyg saturated adsorption capacity.The parameter n represened surface energy inhonogeneity of adsorobent increased with the temperature increasing for E-., oth and Sips modes .The increacemen of racal dimension D in F-L model showed higher temperature ncreased CMS surace inhomogeneityThrough the analysis of the adsopion thermodynamics,the average soster c eat ofCH e adsoption was 1.80 k J/ mol which was comparable to 9.06 k J / mol ofNg.the adsoption of CHt and Ng on this CMS were belong to physical aosorption.Wih the increase of asoptonthe isoster e heat range of N2 was larger than that of CH4.