Drying behavior of prina (crude olive cake) using different types of dryers

Abstract

The purpose of this research is to investigate the drying kinetics and determine the suitable drying method of prina, which is obtained after pressing of olives in olive oil factories, and which cannot be used efficiently in certain sectors. Drying experiments were performed at drying temperatures of 60 degrees C, 70 degrees C, and 80 degrees C at a fixed air velocity of 2m/s using a hot air dryer and with microwave powers of 90W, 360W, and 600W using a microwave dryer. The prina layer thicknesses were selected as 7, 9, and 11mm for both drying methods. The minimum energy consumption values were measured as 42.0Wh for 600W power level and 7mm layer thickness, and 10260Wh for 7mm layer thickness and 80 degrees C temperatures. It was found that energy consumption during hot air drying was more than that of microwave drying. As a result, the suitable dryer and thickness of layer were selected as microwave dryer and 7mm, respectively. The results of statistical analyses showed that the most suitable model to define the drying behavior of prina samples were found to be the Page model for the microwave dryer and Wang & Singh model for the hot air dryer. Also, penetration depth, the loss tangent value (tan), dielectric constant of material (E), and dielectric loss factor (E) of dried prina were calculated as 34.51cm, 0.1059, 75.65, and 8.01, at 2450MHz, respectively.