Modelling and experimental analyzes on air-fluidised silica gel-water adsorption and desorption

In this paper a novel modelling method for performance prediction of silica gel-water adsorption and desorption air-fluidised systems is presented. The mathematical model describing these phenomena was developed and extensive experimental research was carried out to validate the model. Experiments were performed for desiccant particles diameters in the range of 1-5 mm, air superficial velocities in the range of 2.3-6.2 ms-1 and inlet temperatures in the range of 17-72 °C. Main statements of the model were experimentally confirmed, namely during adsorption the mass transfer controlling mechanism is air to air film convection while during desorption it is intra-particle diffusion. Developed model gives reliable results for modelling adsorption and desorption of silica gel-water in air-fluidised systems, especially for desiccant particle diameters smaller than 3 mm. Moreover, superficial velocity, particle diameter and air humidity influence the adsorption and desorption performance. Kinetics of the adsorption and desorption enhance for larger air superficial velocities and smaller particle diameters. Increase of air humidity causes speeded adsorption and slowed desorption.