Simulation of instationary drying processes

The project goal is to provide a belt dryer for small capacities using a novel data acquisition and process control system using control of product quality to efficiently and continuously produce high quality agricultural products. The belt dryer is mobile and can be used for a multitude of products. The new technology is expected to improve product quality, to shorten the drying time and thus to save energy. Due to the low acquisition costs and high flexibility it will also be affordable for producers in developing countries which will help them to enhance their sales opportunities because of the improved product quality. Simulation of instationary drying processes of agricultural products The quality of dried products mainly depends on temperature and moisture content changes during the drying process, as they govern the quality determining reactions that take place during dehydration. The temperature and moisture fields developing in the drying material during drying can be determined by solving the governing differential equations. They describe the heat and mass transport in the material and on its surface. For the determination of the temperature and moisture distribution, a lumped parameter model of the drying material is established, using discretization and calculation methods known from aerospace engineering. These methods are originally used for simulation and design of thermal control systems of space- and aircraft. The model provides information on the dependency of heat and mass transport coefficients on local temperature and moisture content. In convective drying of fruits and vegetables the maximum temperature develops at the product surface. As heat sensitive products can be subjected to high air temperatures in the first stage of drying, automatic control of the surface temperature can guarantee for the best drying results. Therefore a lumped parameter model, based on experimental results, for both the drying process of apple slices as well as the automatic control functionality is proposed. The model will be amplified for drying with instationary drying conditions, too.

Sturm, B.; Hofacker, W.C.; Hensel, O. (2009), Automatic control of the drying process of biological materials using optical sensors to acquire surface temperature, color and shape, Annual International Meeting of the ASABE, Reno, Nevada, USA, 21.06.-24.06.2009, Paper Number 096219

responsible : Dr. Anna-Maria Nuñez Vega

Simulation von Trocknungsprozessen empfindlicher biologischer Güter unter Berücksichtigung instationärer Randbedingungen - online published in KOBRA and
Nr. 544 der Forschungsberichte Agrartechnik des Fachausschusses Forschung und Lehre der  Max-Eyth-Gesellschaft Agrartechnik im VDI 

„Die Förderung des Vorhabens erfolgt aus Mitteln des
Bundesministeriums für Ernährung, Landwirtschaft und Verbraucherschutz (BMELV)
aufgrund eines Beschlusses des deutschen Bundestages. Die Projektträgerschaft
erfolgt über die Bundesanstalt für Landwirtschaft und Ernährung
(BLE) im Rahmen des Programms zur Innovationsförderung.“