Pure and Binary Adsorption Equilibria of Methane and Nitrogen on Zeolite 5A

Adsorption isotherms of pure methane and nitrogen and their binary mixtures on Zeochem Co. zeolite SA were measured using a static volumetric apparatus. Pure isotherms were measured at (273, 283, 303, 323, and 343) K and pressures up to 10 bar, while binary data were measured at (303 and 323) K and different pressures and bulk gas phase compositions. Experimentally measured data were validated using the integral thermodynamic consistency test. In contrast to the aforementioned binary measurements, predictions of different thermodynamic models utilizing pure adsorption isotherms were used to describe binary adsorption behavior of methane and nitrogen over zeolite SA. Models based on the thermodynamic theory of solutions such as ideal adsorbed solution theory, vacancy solution models, and two-dimensional equations of state were used for this purpose. Experimental and predicted equilibrium data were compared through the appropriate phase diagrams. Predicted selectivity curves were compared against experimental data. All the proposed models are capable to describe adsorption equilibria of the investigated system. Results of the present study show that methane and nitrogen form an ideal and energetically homogeneous adsorptive system on Zeochem Co. zeolite 5A.