Adsorption equilibrium and kinetics of water vapor on different adsorbents

Abstract

Water vapor needs to be removed from many industrial streams using, for example, adsorption processes. Equilibrium and kinetic data are essential for the design of these adsorption processes. In this work, the adsorption equilibrium isotherms of water vapor were measured at 303 K by a gravimetric system on three commercial adsorbents, an activated carbon, an activated alumina, and a zeolite. The zeolite sample presented the highest capacity at low relative pressures, while at pressures near saturation the higher amount adsorbed was obtained on the alumina sample. The experimental points obtained for the activated carbon and the zeolite were fitted with the Virial isotherm while the n-layer BET equation was used in the fitting of the alumina data. The adsorption kinetics was evaluated through the analysis of breakthrough curves obtained at the same temperature for different feed humidity values. The fixed bed behavior was described using an isothermal model that includes axial dispersion and external (film model) and internal (homogeneous LDF model) mass transfer resistances. The homogeneous diffusivity values were determined by adjusting the model to the experimental data. © 2008 American Chemical Society.