Abstract

The profiles of the material transfer properties in porous products such as Spirulina platensis during drying which characterize their behavior are often determined from different experimental points by destruction of the samples. However, for a long drying time, it’s impossible to slice or cut the sample correctly because of its mechanical strength and friability. It influences the evaluation of product in cylindrical form properties during all periods of drying. The study aim to propose a model to determine the evolution of water parameters of the micro-alga Spirulina platensis during an isothermal drying. A diffusive model taking into account the deformation and the mass flow of the product is proposed. The digital resolution and the experimental measurements over a period of 120 h of drying have shown a  variation of water content (kgw/kgdm) of the order of 3.12 at 0.41 in the opposite direction of the product thickness and of flow (kgw/m2.s) in the order of 9.26 10-10 at 2.63 10-8. The proposed model satisfactorily validates the experimental drying kinetics over all drying periods and the water content profiles for thicknesses less than 10 mm. The value of R2 obtained is of the order of 0.980, indicating a good correlation between the experimental and predicted data; whereas the root mean square error is around 0.013, showing a very good match between experimental and modeled kinetics.

Key words: Modeling, experience, drying processus, properties evolution, microalgue spirulina, deformation.