PETpla.net Insider 04 / 2019

MATERIALS / RECYCLING PET planet Insider Vol. 20 No. 04/19 www.petpla.net 15 Added Substances). These elements are formed when, for example, PVC or other additives are melted down. When melted at high temperature, the substances can produce all sorts of unwanted by products. Creating a solution Some brands has recently stated: More than 50% mechanically recycled PET cannot be used as this would result in excessive yellowing. In some countries it is possible to use 100% rPET, like Austria, Germany, Great Britain or Japan for example. The deposit system and the high in-put quality makes it possible. Colours are a problem, an enhanced, efficient decontamination, according to the limonene and NIAS value. All in all, a recycling system had to be robust as aluminium and steel or other abrasive contaminants could also be found in the post-consumer material. Last but not least, conversion costs had to be kept as low as possible. “We got together with Polymetrix. The name of the programme is Vacunite which unites vacu um and nit rogen (hence the name). The system has three main components: two from Erema and one from Polymetrix. Polymetrix has devel- oped an SSP (Solid State Polyconden- sation) in line with our suggestions. It has already been patented and will be distributed solely by Erema”, said Christoph. The first step is a refined version of Vacurema Basic. Thanks to the energy input by mechanical friction, the Vacu- rema technology can handle dust and friction very well. The special feature of Vacunite technology is that the reactor is purged with high-purity nitrogen to further reduce yellow colouration. The first processing step has Efsa and FDA approval, so decontamination takes place already before the SSP. With further decontamination in the SSP, it has an enhanced safety capability, comparable with a car safety belt and airbag. The system has short melt- paths, high and constant viscosity and proven filtration. A flake input of 0.76 results in an output of 0.74dl/g. The second step is inline crystal- lisation. As a rule, all pellet SSP sys- tems currently on the market require post-crystallisation before being integrated in the SSP. This involves additional aggregate and extra exter- nal energy. “We do not need that. We manage to achieve a high crystallisa- tion value that enables us to directly feed into the SSP process, i.e. it is a compact system.” Christoph explained. The third step is the patented SSP. In the pre-heater which is nitrogen operated, the system heat to process temperature and transport the hot pel- lets with nitrogen into the SSP where the vacuum is employed at a gentle low pressure. The Vacunite process enables very high crystallisation rates without having to install an additional post-crystallisation. The nitrogen is purified with water pumps so that it can be returned to the upstream process steps, thus reducing overall nitrogen consumption. The material remains in the SSP. The system is designed for approxi- mately nine hours operation which, can be adjusted according to need and residual contamination. “With a residence time of nine hours, we can achieve a viscosity rate of 0.83 dl/g in the final pellet which is ideal for bottle production,” Christoph stated. The technol- ogy was devel- oped specifically for the require- ments in the pro- duction of taste sensitive products such as water bottles. A water bottle places the toughest demands on the decontamination unit and colour- ing. Christoph went on “The PET water bottle has the highest market growth rate, according to Euromonitor: it`s shifting from CSD to water bottles.” Finally, a fluid- ised bed has been installed. Here, the pellets are cooled and de- dusted to achieve a high degree of bottle transparency after preform production. The system’s dimensions are compact. Overall, Vacunite requires 40% fewer compo- nents than comparable systems. “An extra bonus is the pre-installation, i.e. we have a very limited installation time on site.” Christoph is pleased to report. In summary, Christoph says “We have a very well controlled process with double food-contact approval, as well as extremely low energy con- sumption. It is as low as our Vacu- rema Prime, now lying at 0.35 kWh/g. As an end product Vacunite technol- ogy produces rPET pellets which are unique in terms of quality and far exceed all legal food-contact requirements as well as the even higher requirements of leading brand owners”. Thanks very much to Christoph Wöss for talking to us at All4Pack Paris and the Petcore conference in Brussels in 2019. www.erema.com With HSM − turn your waste into valuable material! HSM Baling presses are specialised when it comes to compressing waste materials. Whether you opt for a horizontal baling press, a vertical baling press or a channel baling press – you will always select a quality machine „Made in Germany“. www.hsm.eu