Characteristics and Kinetic Model of Far-infrared Vacuum Coupled Drying of Winter Jujube

Abstract

In order to study the influential characteristics of the far-infrared vacuum drying on winter jujubes, this paper has adopted the far-infrared vacuum drying technology to study the effects of different slice thicknesses, relative pressures and far infrared radiation temperatures on the drying characteristics and effective moisture diffusivity of winter jujubes and establish the drying mathematical equation model. The results show that during the drying of winter jujube slices, the drying rate of jujube slices is directly proportional to the radiation temperature and relative pressure, and inversely proportional to the slice thickness. The effective moisture diffusivity of winter jujube slices is 0.9757~5.1795×10-8m2/s, and the change of thicknesses of winter jujube slices has the most obvious effect on the moisture diffusivity. Through fitting nine commonly used drying models, the best fitting effect of the far-infrared vacuum drying for winter jujube slices is obtained by Midilli et al. kinetic model. The fitting verification of the model shows a good fitting effect between the predicted values and the experimental values, which can effectively predict the far-infrared vacuum drying process for winter jujube slices.