Abstract

VEGA GALVEZ, Antonio; TELLO IRELAND, Cristian  and  LEMUS MONDACA, Roberto. MATHEMATICAL SIMULATION OF DRYING PROCESS OF CHILEAN GRACILARIA (GRACILARIA CHILENSIS). Ingeniare. Rev. chil. ing. [online]. 2007, vol.15, n.1, pp. 55-64. ISSN 0718-3305.  doi: 10.4067/S0718-33052007000100008.

The aim of this research is to study and to model the hot air drying kinetics of Gracialaria algae (Gracilaria chilensis), using a convective drier -designed and built at the Faculty of Engineering of Universidad de La Serena- at five dry bulb temperatures (30, 40, 50, 60 and 70^oC) and an air velocity of 2.0 ± 0.2 m.s^-1. Three empirical models are used for the mathematic modeling (Newton, Henderson-Pabis & Page). During the experiment, only a falling rate period is observed, hence the Fick's second law equation is used to estimate the effective water diffusivity. The drying process shows final moisture contents between 0.096 g water/g d.b. and 0.061 g water/g d.b. for 30^oC and 70^oC, respectively. Both diffusivity and kinetic parameters k1, k2 and k3 of the proposed models show dependence on temperature, and when being evaluated by the Arrhenius equation, activation energies of 39.92, 33.85, 33.49 and 33.83 kJ·mol^-1 are obtained, respectively. According to the statistical analyses used (r2, SSE, RMSE and X²), the Page model shows the best fit quality on experimental data, thus being considered an excellent tool for the kinetic modeling of industrial drying processing of Gracilaria chilensis and the estimation of drying time at different temperatures, in order to achieve a commercial moisture content to be acceptable abroad.

Keywords : Gracilaria; drying; diffusivity; Arrhenius; Page.