Adsorption of light gases and their mixtures on SR-115 and ETS-10 Zeolites

Abstract

Pure binary and ternary equilibrium adsorption data of methane, ethane ethylene, nitrogen and carbon dioxide on both SR-115 and ETS-10 zeolites are reported upto 1000 kPa pressure and a temperature range of 280-425 K. Ten pure models namely Toth, Unilan, Radke-Prausnitz, Mathews-Weber, Volmer, Virial with two and three constants, Freundlich, Langmuir-Freundlich, and the Loading Ratio Correlation are successfully applied to model the pure data using unconstrained and constrained optimization techniques. Henry's constant values and limiting heat of adsorption are extracted from the Virial three constant model and are compared to the values obtained from other models. The ideal adsobed solution theory in conjunction with the pure isotherms of Toth, Unilan and Virial three constant is used to model the multicomponent data. The fit of this model to these data is satisfactory except for the data of the binary system nitrogen-carbon dioxide on SR-115 zeolite. The latter poor fit may be attributed to adsorption of carbon dioxide on the binder. Values of the relative adsorptivity calculated from the data and the IAST fits of the data show that the separation of methane from ethylene is feasible on both adsorbents; but it is best on ETS-10 zeolite. Also, the separation of methane from ethane, and ethane from ethylene is feasible on ETS-10 particularly at low temperature. The separation of ethane from ethylene is not possible on SR-115 zeolite at any conditions. However, the separation of methane from the ternary mixture methane-ethane-ethylene is possible on both types of zeolites at any conditions.