Modeling of Water Vapor Adsorption and Desorption in an Industrial Medical Air Dryer

Thisstudy presents the development of a dynamic multiscale modelto simulate the adsorption and desorption processes in a fixed bedfor medical air drying. The model includes equations of mass balance,thermodynamics, hydrodynamics, and adsorption/desorption kinetics.The temperature-dependent Toth-Aranovich-Donohue equationis used to approximate the equilibrium relationship between watervapor and activated alumina (hopcalite). Measurements of the breakthroughcurve at different water vapor concentrations and gas flow rates canbe used to determine kinetic resistances such as axial dispersion,external film mass transfer, pore diffusion, and internal mass transferand thus to determine the limiting resistance of the process. Themodel predictions agree well with the experimental results, whichare supported by performance indices and confirmed by additional breakthroughcurves for validation. The validated model proves effective in predictingwater vapor adsorption and desorption breakthrough curves on adsorbentsconsidering concentration, flow rate, and temperature and serves asa valuable tool for the development and optimization of commercialPSA columns with multiple adsorption layers.