Parametric study of pressure–temperature swing adsorption for gas dehumidification on two-layered bed of porous desiccants.

A two-layer cyclic pressure–temperature swing adsorption system was designed for effective water vapor removal from air or helium. The system consists of two fixed bed adsorption columns, each containing two layers of adsorbents consisting of silica gel and zeolite molecular sieves 13×. To gain in-depth insights about the process, a descriptive model considering mass, energy and momentum balances, along with kinetic and equilibrium equations has been developed. The results of computer simulation showed that the layered bed, containing silica gel and molecular sieves 13×, offers both a longer water breakthrough time and significantly enhanced two-layered bed desorption performance compared with those for the one-layered bed. The influence of total gas pressure during the adsorption step, and height of the adsorbent layers on the process efficiency were studied. The cyclic steady state cycles were obtained under various conditions by a cyclic iteration method. Condensation of desorbed water in the adsorbent bed during regeneration has been considered. Theoretical study indicated no water vapor condensation. [ABSTRACT FROM AUTHOR]