Treatment of odour-contaminated post-consumer plastics
A large amount of plastic waste from consumer-market packaging is generated daily. In order to obtain high-quality plastic recyclates from these material streams, and to be able to make them reusable for high-quality applications, odorous substances that have migrated into the material during the course of the product-life must be removed. Up till now, these odourous substances could be removed only inadequately through recycling processes. Kreyenborg intends to change the scenario with the introduction of the new modular system IR-Fresh.
In the first process step, an infrared module installed above the material bed heats the material quickly and directly to the optimum temperature level for the plastic in question. In this process, the continuous rotation of the drum ensures a homogeneous mass flow with a defined dwell time (applying the first-in/first-out principle). Due to the rotation and mixing elements integrated in the spirals, the material is continuously mixed in the drum with constant surface exchange. Combined with controlled heating, this ensures considerable odor elimination, even within a short residence time, states Kreyenborg.
In the second process step, the remaining odourous substances in the regrind or granules are removed by a thermal-physical cleaning process in the IR-Fresh Conditioner. This Conditioner – an insulated hopper – keeps the material to be decontaminated at a temperature range ideal for the decontamination process by means of a hot purge-gas. According to Kreyenborg, excellent results for deodourisation and decontamination can be achieved through the interaction of the main process parameters of air-flow, temperature, and residence time.
Due to its modular design, the IR-Fresh process can be used continuously in two stages both for regrind – before the extrusion process – and for granules after the extrusion process. It is possible to either integrate the IR-Fresh Conditioner as an individual step in the process chain or to operate it as an independent, stand-alone solution either continuously or discontinuously. The system is also suitable as a retrofit solution for integration in existing plants.
