PETpla.net Insider 04 / 2018

TRADE SHOW PREVIEW PET planet Insider Vol. 19 No. 04/18 www.petpla.net 53 technology co-operation has to be fostered, in order to raise PET pack- aging’s recylclate content. The PET recycling technologies currently available are detailed in Table 1. The table shows that only Uhde Inventa-Fischer’s (UIF) FTR technol- ogy can produce high quality, virgin- like PET resin, economically, at high production capacities, claims the com- pany. Since UIF introduced its pro- prietary, FDA-approved FTR in 2007, several FTR units have been brought into production at PET manufacturing sites in the US, EU and Asia. Units are designed to be attached to newly- installed PET manufacturing plants but they can also be integrated into existing plants using MTR (Melt-to- Resin) technology, as well as conven- tional SSP lines. What does the FTR process look like? Post-consumer recycling (PCR) flakes undergo a two-step process. First, impurities are removed; then, the PCR material is remanufactured to a virgin-like, bottle-grade resin. The PCR flakes are fed into an extrusion unit, where they are gently transferred into the melt phase. The first decon- FTR technology by UIF Physical recycling Chemical recycling to raw material Description Partly glycolysis and feed before Finisher Reactor (when combined with MTR, Discage reactor) Bottle to bottle process with pre- or post-treatment for de- contamination and viscosity adjustment of flakes/pellets Mostly catalytic break-up of PET by Hydrolysis, Glycolysis or Methanolyis Product Virgin-like PET resin with adjustable rPET content rPET, to be mixed with virgin PET at preform making Raw Material PTA & EG, or DMT & EG, or intermediate product BHET. By-products are challenging De-contamination steps Including pre-washing: 4 steps. Most powerful de-contamination in Finisher. Including pre-washing: 3 steps Complete de-polymerisation Filtration Fine filtration of glycolysed melt at low viscosity Filtration at high viscosity Complete de-polymerisation Sensitiveness to PRC flakes quality Sensitive, pre-sorting can be integrated Sensitive Not sensitive CAPEX & OPEX Medium-Low Medium Very high Proven technology Yes Yes Only Methanolysis has been oper- ated for some time. FDA approved EFSA approved Yes up to 50 % PCR flakes Yes, ruled as chemical recycling Yes Yes Methanolysis: yes, other no, but approval is no issue Table 1: Survey of PET recycling technologies MTR is UIF’s proprietary Melt-to-Resin technology. It produces high viscosity PET resin in an integrated process, without a Solid State Postcondensation (SSP) unit. tamination is performed by applying vacuum to the melt, with low boil- ing components like water or acetic aldehyde being effectively removed. At the same time the PET is partly glycolysed, by feeding a defined amount of ethyleneglycol (EG), so as to achieve the same intrinsic viscosity (IV) as virgin pre-polymer. EG dosing is controlled by an on-line viscosi- meter. The melt is passed through a highly efficient filtration system, for removal of solid impurities like traces of paper, coatings, dirt, etc. Finally, it is combined and admixed to the virgin pre-polymer stream from the poly- condensation plant, before the final stage in the polycondensation reactor (Discage). Cleaning in the Discage reactor is under high temperature and high vacuum conditions, which allows the removal of even very high boiling con- taminant. The reactor also increases the viscosity of the polymer melt to the required final level. The melt leaving the reactor is subject to a final filtra- tion, where any remaining impurities are removed. An underwater pelletis- ing system converts the PET melt into pellets. The final step is the removal of acetaldehyde in a conditioning silo, operated at mild temperature and with air atmosphere. Diagram 3: FTR concept with part depolymerisation and feed into virgin PET-pre- polymer stream