Experimental Investigation and Thermodynamic Modeling of CH4/N-2 Adsorption on Zeolite 13X

To implement an experimental study of CH4/N-2 adsorption on Zeochem Co. zeolite 13X, a volumetric apparatus was utilized in this regard, pure adsorption isotherms were measured at different temperatures [(273, 283, 303, 323; and 343), K] and pressures up to 10 bar, While binary data were collected at (363 and 323) K and different pressures and bulk gas phase molar fractions. Integral, and differential thermodynamic consistency tests (TCT) were performed to validate the collected data and certify accuracy of the measurements. To have a thermodynamic view over the investigated system, thermodynamic functions such as enthalpy, entropy, surface potential, and Gibbs free energy were estimated numerically. Besides, the measured pure isotherms were regressed using different isotherm equations and the regressed parameters were applied to different models based on the thermodynamic theory of solutions, i.e., ideal adsorbed solution theory (IAST), vacancy solution models (VSM), and Peng-Robinson two-dimensional equation of state (PR 2D-EOS). All the models were applied in the predictive scheme. Experimental and predicted adsorption data were compared through the appropriate phase diagrams. Almost all the models could predict binary adsorption behavior of CH4 and N-2 over zeolite 13X.