Identification of the Water Diffusion Coefficient, from the Kinetics of Convective Drying of a Clay Plate

In this work, we present a methodology to estimate the water diffusion coefficient of a clay slab during convective drying by hot air. This parameter was determined using a numerical method by minimizing the difference between the points of the experimental and simulated drying kinetics. The resolution of the transfer equations of the solid and liquid phase was done using the finite volume method, which takes into account the shrinkage rate of the clay during drying. The diffusion coefficient, as a function of temperature and water content, varies from 1.33 × 10−11 to 5.95 × 10−11 m2/s. The Arrhenius relationship with an activation energy value of 683.73 J/mol clearly shows this effect of temperature on the diffusion coefficient. A predictive correlation of diffusivity as a function of temperature and water content was determined for the type of clay studied.