Waste Heat Utilization for Granule Preheating in Extrusion Processes to Increase Energy Efficiency

Modem extrusion processes require 40% - 60% more energy than physically necessary. This excess of energy is mainly due to high heat radiation. One of the main sources of heat is dissipation. In order to ensure stable thermal conditions, the barrel is tempered externally with heating and cooling elements and discontinuously operated radial fans. As a result, warm air is discharged unused to the environment. In a new concept, the warm air is to be collected by a manifold and a central, continuously controlled, suction fan. This warm air is used for granule preheating. During the fust development steps, the manifold, the barrel housing and the granulator funnel were already designed with the help of "Flow Simulation". Therefore, the flow simulation yields potentials of flow conditions caused by different flow geometries. The next step is an adaption of the control technology for the control of the suction fan and the throttle valves in order to be able to control the temperature of each barrel zone.