Modeling the drying of a deep bed of Ilex paraguariensis in an industrial belt conveyor dryer

Abstract

The evolution of temperature and moisture content of leaves and twigs of yerba maté on different levels of a through-flow dryer was investigated by modeling heat and mass transfer using the finite difference method. To validate the model, the temperature and moisture profiles were used to estimate chlorophyll losses. Great variations were obtained in moisture, temperature, and chlorophyll content at different levels of the bed. Leaf temperature quickly increased in the former nodes, and it then increased slowly until it reached air temperature. In the twigs, the temperature increase was slow and the air temperature was never reached.