PETpla.net Insider 09 / 2021

PETplanet Insider Vol. 22 No. 09/21 www.petpla.net 49 EVENT REVIEW 5. PETinar: Disruptive technologies and innovative additives for PET recycling The fi fth PETinar organised by PETplanet insider took place on June 16, 2021. PETplanet invited Dr Axel Hannemann and Dr Carl-Jürgen Wefelmeier from Gneuss and Alessandra Funcia from Sukano to talk about Disruptive Technologies and Innovative Additives for PET Recycling. Gneuss and Sukano presented new recycling technologies focussed on shifting towards recycling PET waste from sources such as post-industrial fi bre waste or other post-consumer sources, such as thermoformed PET trays. Dr Axel Hannemann, Head of Fibers & Pellets at Gneuss, started the PETinar introducing the com- pany Gneuss by explaining its four business units: the first unit is about filtration technology, where rotary screen changers were developed. The second business unit covers the measurement technology design- ing melted pressure- and tem- perature sensors. Some 15 years ago, Gneuss started with the third business unit - extrusion technol- ogy. And finally in the fourth unit, Gneuss brought all production areas together to offer turnkey solutions to its customers. Gneuss bottle-to-tray recycling solution Dr Carl-Jürgen Wefelmeier took over and continued with some detailed information on the various Gneuss PET recycling lines with a special focus on Gneuss post-consumer tray recycling concept. As a bottle-to-tray recycling solution, Gneuss offers its Gneuss Processing Unit (GPU) con- sisting of a rotary fi ltration system, an MRS extruder, a vacuum system for the extruder and an online Viscometer system (VIS). The whole Processing Unit can be integrated, for example in a sheet line. The MRS extruder works with- out any pre-treatment, no pre-drying and no crystallisation of hygro- scopic polymers. Its flexibility means the system saves a lot of space and energy. For processing post- consumer rPET Gneuss adds after melting a special multi-rotation step, where degassing and decontami- nation in vacuum takes place. This leads to an EFSA or FDA food- approved application. The MRS extruder is based on the conventional single screw extruder. It is equipped with a multiple screw sec- tion, for optimum devolatilisation. The polymer melt is delivered into a large single screw drum. The drum contains eight small extruder barrels, parallel to the main screw axis. Installed in these small extruder barrels are the satellite- screws, which are driven by a ring gear in the main barrel. The satellite screws rotate in the opposite direction to the main screw while they rotate around the screw axis. This disproportionately increases the surface exchange of the polymer melt, so that the volatiles can be freely evacuated. The extruder is equipped with a large opening for venting (exposing the full length of the satellite screws) which is completely under vacuum. This provides unrestricted access to the polymer melt, the surface of which is constantly replaced at an extremely high rate by the action of the satellite screws in the multiple screw section. Precise control of the melt temperature is possible as the temperatures of all the surfaces in contact with the melt can be controlled accurately. The special rotary filtration system called RSFgenius , is fully- automatic and extremely pres- sure- and process constant. With an integrated back flushing system, it is possible to reuse the screens very often. Self-cleaning and back- flushing waste of the RSFgenius filter system is five times less then with conventional purging filter. Dr Axel Hannemann, Head of Fibers & Pellets at Gneuss Dr Carl-Jürgen Wefelmeier, Head of Film & Sheet at Gneuss by Heike Fischer PETINAR