Investigation of the processes of impregnation and drying of granular silica gel

The process of capillary impregnation and drying of silica gel grains in the acousto-convective drier of the ITPM of the Siberian branch of the Russian Academy of Sciences has been investigated experimentally. Two methods for humidifying a material with developed surface and internal structures have been considered. A comparison of these methods has been made and the influence of the impregnation rate on the geometry of silica gel grains has been analyzed. Silica gel grains were dried by three methods: microwave, convective, and acousto-convective. The dependence of the drying rate and the quality of the dried material on the chosen drying method has been shown. To describe the moisture extraction, we propose a mathematical model based on a two-dimensional diffusion equation written in the cylindrical system of coordinates. The moisture distribution in cylindrical samples consisting of silica gel grains has been obtained numerically for various values of the initial moisture content with the use of certain diffusion coefficients and the dependence of the moisture transfer coefficient on the frequency of acousto-convective action.