Deposition of solids within porous materials from a drying solution is an important phenomenon in numerous natural and industrial processes. A profound knowledge about influences of different parameters on the solid distribution in the material is required for an effective targeted impregnation process. Experimental investigations and simulations are used to study the influence of pore structure, drying conditions and solute concentration on the solid distribution in porous support materials after impregnation and drying. It is found that low drying rates lead to strong solid accumulation at the material surface, whereas high drying rates reduce the solute transport to the surface and result in more uniform solid distributions. A small pore diameter and distribution width reduces solute migration during drying and leads to uniform solid distributions without being influenced by the drying conditions. A higher initial concentration of the impregnation solution causes pronounced surface accumulation while low initial solute concentrations result in more uniform distributions. Fundamental effects during drying are captured in an existing pore network model by adaption of experimental pore structures and impregnation-drying conditions resulting in good general agreement of experiments with simulations.

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In this work, an isothermal pore network model has been utilized to investigate ion transport and crystallization in layerd porous media during drying. Said network consists of two distinct layers each  with a different pore size distribution. One-dimensional approximation at the throat level describes transport phenomena for liquid, vapor, and dissolved salt. An explicit time stepping scheme has been used to obtain fluid pressure fields and ion concentration. Various simulations are carried out which indicate the effect of mean pore size disparity in the top and bottom layer, as well as the effect of drying rate on final crystal distribution.   Keywords: pore network modeling, composite material, drying porous media, crystallization, ion transport.

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