Simulation and Optimization of Semicontinuous Industrial Tunnel Dryers for Fruits

Semicontinuous industrial tunnel dryers were simulated and optimized for concurrent and countercurrent configurations. Mass and energy balances for the solid and gas phase were used to describe the operation of the dryer and a semi-empirical model for the mass transfer rate; the drying rate equation parameters were fitted using experimental data for Italy grapes. The simulation programs coded in Fortran 90 calculate the moisture and temperature profiles for grapes and humidity and temperature for air throughout the tunnel, cycle time, recirculation ratio, thermal load, and fresh air flow rate. The optimization minimizes the energy input considering the degradation of ascorbic acid in the fruit as the main constraint.