At this year’s ITMA, Gneuß Kunststofftechnik GmbH, Bad Oeynhausen/Germany, will be presenting its innovative PET recycling process for the use of industrial and post-consumer waste in direct spinning.
The Recycling Technology enables the processing of high-volume, industrial PET waste from fiber, nonwovens or film production, and from contaminated post-consumer bottle flakes. The technology is based on the Gneuss Processing Unit (GPU) with MRS extruder, rotary filtration system and online viscometer with intelligent viscosity monitoring and control, optional combined with the Jump reactor.
In the first processing stage, melt decontamination takes place in the GPU. With its good devolatilization capacity, the MRS extruder can process PET waste with high residual moisture levels and/or contamination (such as spin finish oils) without the need for any pre-treatment of the waste. In the Multi-Rotation Drum, multiple satellite screws produce a large melt surface and surface exchange rate, so that an optimum devolatilization and decontamination result can be achieved with conventional water ring vacuum pumps. All volatile impurities such as water and/or spinning oils are safely removed eliminating disturbances in the spinning process.
Solid impurities are subsequently filtered out by the melt filter. Rotary filtration systems operate continuously, process constant and automatically, and guarantee a particle-free melt thanks to finest filter elements with filter fineness down to below 20 µm.
With the Online Viscometer VIS, the melt viscosity is measured in real time and directly adjusted. Depending on the recycling process, the viscosity is specifically reduced by means of ethylene glycol injection or in a further step specifically increased in the IV boost system Jump. After passing through the MRS extrusion line, high-viscosity input material does not require any further IV treatment.
Subsequently, the polymer melt is merged with the main, virgin polymer melt flow either upstream or downstream of the finisher.
With this recycling technology, combining an MRS extruder with the optional Jump reactor, industrial and post-consumer waste can be turned into a high-quality and directly usable melt in a very short time. Thanks to the enormous line flexibility, different PET qualities can be produced.
This recycling concept for processing fiber waste into pellets will be implemented by a large Chinese manufacturer. An MRS130 will process up to 900 kg/h of fiber waste (staple fiber and POY) into melt. All the spin finish oil, water and other volatiles will be taken out in the highly efficient degassing section. There is a possibility for adding of color (TiO2, carbon black etc.) as well as other reactive additives. After the devolatilization in the MRS all solid particles will be filtered out by an RSFgenius175 equipped with 20 µm screens. The purified melt will be fed via a startup valve into the reactor for the IV lift. Alternatively, in this line set-up, there is an option to feed the melt directly (before the reactor) to a pelletizer to produce pellets with a lower IV.