Recycling: Advances in Direct PET Decontamination

Germany’s Kreyenborg says its IR-CLEAN system offers an alternative for post-consumer materials and direct decontamination processing of PET— without any kind of vacuum technology.

The system is an advanced development in the process technology of the Infrared Rotary Drum (IRD) used in hundreds of industrial applications. The standard process of crystallization and drying of PET post-consumer bottle flakes in the IRD has been refined by various changes in the process parameters and technical modifications.

This has resulted in good decontamination results, which have been proven in tests in collaboration with the Fraunhofer Institute for Process Engineering and Packaging IVV. The Food & Drug Administration (FDA) has issued a Letter of Non-Objection on the basis of these values. These results can also be used for the limits, fixed on behalf of the European Food Safety Authority (EFSA)—depending on the use of the end product up to 100% of post-consumer material.

The general functional principle of the IRD is the low mass in the process and the continuous movement of the material, which ensures a continuous surface exchange of the recycling material to be treated. Combined with the direct heat input from the infrared light, which generates high temperatures within a few minutes, the IR-CLEAN concept reportedly doesn’t require expensive and high-maintenance vacuum systems.

IR-CLEAN combined with a downstream finisher, which takes the form of a desiccant air drier, gives drying values of <50ppm.

The IR-CLEAN system achieves the FDA/EFSA values already upstream of the extruder, facilitating easy retrofitting and an FDA/EFSA approval of existing single-screw, twin-screw or multi-screw extrusion systems. The package, comprises not only the conveying technology, but also complete process monitoring and documentation of the process parameters.

In the U.S. Kreyenborg is represented by eFactor3.