Equilibrium and kinetic analysis of CO2–N2 adsorption separation by concentration pulse chromatography

CO2 and N2 adsorption kinetics and equilibrium behaviours have been studied with silicalite, NaY and 13X by using concentration pulse chromatography for the separation of these gases in the present study. Adsorption Henry's Law constants, the heat of adsorption values, micropore diffusion coefficients and corresponding activation energies are determined experimentally and the three different mass transfer mechanisms are discussed. From the equilibrium data, the corresponding separation factors are obtained for the adsorption separation processes. The heat of adsorption values as well as the Henry's Law adsorption equilibrium constants of CO2 are much higher than those of N2 for all the adsorbents studied. 13X, NaY and silicalite all have good separation factors for CO2/N2 system based on equilibrium processes. The order of the equilibrium separation factors is 13X (Ceca) > 13X (Zeochem) > NaY (UOP) ≫ silicalite (UOP). Equilibrium selectivity favours CO2 over N2. Micropore diffusion resistance is the definite dominant mass transfer mechanism for CO2 with silicalite and NaY.

Graphical abstractWorldwide atmospheric carbon dioxide levels.Figure optionsDownload full-size imageDownload as PowerPoint slide