Gas—solid diffusion and equilibrium parameters by tracer pulse chromatography

Abstract

Gas adsorption on solid zeolitic adsorbents is the basis of many gas separation processes (e.g. pressure swing adsorption). The accurate design of these units requires gas—solid diffusion and equilibrium data over a wide range of temperature and pressure. Perturbation chromatography has been proven to be a very convenient experimental technique that can be used for the determination of these parameters. Although various types of perturbations can be used, our laboratory has found that the tracer pulse technique, in which a pulse of radioactive adsorbate is injected into the chromatographic system, results in a simpler and more straightforward analysis procedure. In this paper this rather unusual technique will be described in detail, and diffusion coefficients and equilibrium constants obtained for the ethane—silicalite system will be presented.