关键词: 吸附剂, 氮气, 甲烷, 分离, 等温线, 热力学, 动力学

Abstract: The N2/CH4 dynamic adsorption behaviors in eleven commercial adsorbents were investigated. The N2/CH4 separation properties of the adsorbents were discussed by adsorption equilibrium，adsorption thermodynamics and adsorption kinetics，from which the correlation coefficients of adsorption equilibrium，adsorption thermodynamics and adsorption kinetics for N2 and CH4 on the adsorbents were obtained. With Langmuir adsorption model and Freundlich adsorption model，the liner fittings were performed for the N2 and CH4 adsorption equilibrium data. It was found that for the microporous activated carbons，the data could be well fitted by both models，while the linear fitting was an unsatisfactory for non-carbonaceous adsorbents and non-microporous carbon adsorbents. With Gibbs adsorption equation，the N2 and CH4 Gibbs free energies adsorbed in the adsorbents were all below zero， suggesting that the N2 and CH4 adsorption processes in the adsorbents were spontaneous. For carbon adsorbents，the difference of CH4 and N2 Gibbs free energies was lower than zero，indicating that carbon adsorbents had stronger adsorption on CH4 adsorbed than N2. At the same time，there was a certain relation of the CH4/N2 separation factor （α）of the adsorbents and the difference of CH4 and N2 Gibbs free energies. For adsorption kinetics，CH4 adsorption kinetic process in AC1 was studied at different adsorption pressures. The data could be well described with the pseudo-second order kinetic model，indicating that the surface adsorption was the rate-determining process during the process of CH4 adsorption in AC1.

Key words: adsorbent, nitrogen, methane, separation, isotherm, thermodynamics, kinetics