Investigation of microwave dryer effect on energy efficiency during drying of apple slices

Characteristics of thin layer microwave drying of apple were evaluated in a laboratory scale microwave dryer at 2450 MHz. The drying experiments were carried out at 200, 400 and 600 W. The experimental data were fitted to nine drying models. The models were compared using the coefficient of determination (R2), root mean square error (RMSE) and reduced chi-square (χ2). The Midilli et al. model best described the drying curve of apple slices. The effective moisture diffusivity was determined by using Fick’s second law and was observed to lie between 3.93 × 10−7 and 2.27 × 10−6 m2/s for the apple samples. The microwave power dependence of the effective diffusivity coefficient followed an Arrhenius-type relationship. The activation energy for the moisture diffusion was determined to be 12.15 W/g. The highest energy efficiency was recorded for the samples dried at 600 W as 54.34% and lowest at 200 W as 17.42%

Sugarcane Bagasse Gasification in a Downdraft Fixed-Bed Gasifier: Optimization of Operation Conditions

A CFD model for the gasification of sugarcane bagasse in a downdraft fixed-bed gasifier is developed. The objective is to observe syngas yield distribution in different operation conditions and to obtain optimal parameters. Several factors are investigated, including the velocity and preheating temperature of inlet air-steam mixture, steam to air ratio (S/A), and biomass moisture content (MC).<br /

Potential saving in energy using combined heat and power technology for drying agricultural products (banana slices)

The drying behavior of banana slices was studied in a combined heat and power dryer system at 4 engine load levels (25%, 50%, 75%, and 100%) and at three levels of drying product thickness (3, 5, and 7 mm) with the constant airflow velocity of 1 m/s. Results from the mathematical modeling showed that the Midilli et al. model gave the best fit to the experimental data. The present study confirms the importance of heat recovery to improve the system energy consumption and efficiency. Energy efficiency of this dryer was from 11% to 20% higher than that of electricity efficiency. Also, the specific energy consumption varied between 409 and 957 kWh/kgwater. The lowest value of energy consumption and highest value of energy efficiency were observed at 75% engine load and 3 mm thickness of sample