Modeling Kinetic Parameters for Thin Layer Drying of Beans

The removal of a liquid from a solid by evaporation is known as the process of drying. It can also be termed the reduction or loss of moisture content. Preservation of nutritive values and extension of the shelf life of foods are reasons why drying is important. The process of drying takes place under optimum operating conditions and efficient drying rate. This research work aimed at determining the kinetic parameters for thin-layer drying of beans under constant drying conditions necessary for the design of industrial dryer. An experimental work was carried out using an oven drying method which observed the drying of beans to be in the falling rate periods between 45oC to 65oC. The rate of drying was found to have a direct relationship with moisture content and temperature but an inverse relationship with time. The experimental data for beans could fairly be predicted by the Page equation. The values of A and B from the Page equation were found to be functions of temperature rather than mere constants as were used in the model and these are for A between 8.41E-05 and 2.4E-03 for the given temperatures while for B it was between 0.668 and 0.966. Temperature, therefore, is an important parameter to be manipulated in any dryer design especially for hygroscopic grains like beans.