PEREIRA, J. C. A.; PEREIRA, JOAN CARLOS ALVES.; ALVES PEREIRA, JOAN CARLOS.; http://lattes.cnpq.br/9573902090639143; PEREIRA, Joan Carlos Alves.
Resumo:
The technological development of the drying process of agricultural products plays a
fundamental role in minimizing the waste of food. In this sense, intermittent drying has
shown good results, improving the final quality of the product and reducing energy
consumption. This work aims to conduct a study of the continuous and intermittent drying
of rice in the husk using empirical and diffusion models to describe the phenomena that
occur during these processes. Continuous and intermittent drying experiments (with an
intermittence ratio α = 2/3) of rice grains were carried out using a fixed bed drier at
temperatures of 50 and 70oC. Empirical models were used to simulate drying kinetics and
to evaluate which model best fits the experimental data. Through the diffusive models, we
present analytical and numerical solutions of the diffusion equation for the cylindrical
geometry. For the numerical model, the diffusion equation was developed by the finite
volume method, with a totally implicit formulation. Effective drying time for mathematical
modeling and simulation of moisture distributions were considered. The comparison
between the kinetics of continuous and intermittent drying indicated a reduction of the
drying time with the application of the intermittence, providing a greater energy saving. It
has been found that the boundary condition of the first type is the one that best describes
the drying process of the husked rice and that the effective mass diffusivity increased with
intermittent drying. The results state that not only the ratio of intermittence is important for
the reduction of drying time, but also tempering period.