Evaluation of Thermal and Drying Characteristics of Dried Hazelnut (Corylus avellana L.) Shell Waste

Abstract

As a biomass fuel, the hazelnut shell must be milled into sawdust and dried to contain a certain amount of moisture. For this purpose, calorific value, drying rates, thermal values, moisture diffusion, activation energy, and energy consumption at the end of the drying of the hazelnut shell, which is dried in the conveyor belt and microwave dryer, were calculated. The total minimum energy consumed by the hazelnut shell at the end of the experiment in microwave drying was measured as 0.2 kWh for 460 W and 4.65 kWh at 80°C drying temperature in conveyor belt drying until the final moisture value reached 1.1±0.8% wet basis at the end of the experiment. The effective diffusivity of moisture of hazelnut shell changed from 4.13×10-7 to 1.89×10-6 m2 s-1, and the activation energy was found as 2.275 W g-1 in microwave drying. The effective diffusivity of moisture of hazelnut shell changed from 6.39×10-7 to 9.21×10-7 m2 s-1, and the activation energy was found as 19 kJ / mol in the conveyor belt drying. In general, the diffusion coefficient increased with increasing air temperature and decreased with increasing microwave power. At the end of the experiments, the temperature in the product was measured as 72°C in microwave drying and 73.5°C in conveyor belt drying. According to these values, it has been determined that the most suitable drying system for waste disposal was the microwave drying system. The calorific value was measured as 20028.52 kJ/kg in conveyor belt drying and 20036.76 kJ/kg in microwave drying. Microwave drying yielded better results with an increase of 2.72%.