IMPACT OF AMBIENT AIR HUMIDITY ON THE WARPED APPARENT ACTIVATION ENERGY OF DRYING MATERIALS

Based on the concept of AAE(apparent activation energy), the warped apparent activation energy (WAAE) is introduced into the reaction engineering model in order to simplify the model. In the paper, the drying dynamic performance of three kinds of dried materials, potato, soap and silica gel, was studied by investigation of the impact of the drying medium (hot-air) relative humidity, which is 8%, 15% and 25%, on the WAAE of dried materials. The studied results show that the WAAE not only reflects the comprehensive effect of water evaporating resistance caused by capillary of porous solid, shrinkage of material surface, but also appears to the diffusivity of vapor molecule in drying medium during drying process.