Simulation and Optimization of a counterflow Tunnel Dehydrator

Abstract

A widely used class of vegetable dehydration systems are the “tunnel-and-truck” dehydrators , where the prepared material lies over horizontal trays stored in trucks which move discontinuously in opposite direction of the air flow. This way the driest product is facing the inlet hot and dry air blowed to the system. When product of one truck is ready, is removed from the tunnel leaving space for advance the remaining truck one place forward. This way, a new truck full of wet product can be inserted at the end of the tunnel. This paper presents a simulation model of a particular dryer design, including the tunnel, a fan and a heating coil. Additionally there is some energy saving equipment like a recovery heat exchanger and recirculation damper. The simulation model is then applied to the determination of optimal operating conditions.