Applying Liquid Diffusion Model for Continuous Drying of Rough Rice in Fixed Bed

Abstract

Simulate the rice drying process at specific drying conditions is of great interest to optimize the process and ensure a better quality of the final product. In the present work, experimental drying procedures of rough rice grains (BRSMG CONAI variety) was reported and drying kinetic was obtained at temperature using 40°C. The results were compared with simulated data by means of the liquid diffusion model equilibrium boundary condition. The geometry used to represent the rice grain was prolate spheroid. For this purpose, the diffusion equation, written in cylindrical coordinates, and solved via Galerkin-based integral method considering the constant diffusion coefficient. A good agreement was observed between predicted and experimental data. It was also possible to observe that the highest moisture gradients occur at the tip of the grain, which is region more affected by thermal and hydric stresses. The studied model can be used to solve problems involving diffusion processes, such as: drying, wetting, heating and cooling, provided that the geometrical shape of the body is similar to prolate spheroid.