TECHNOLOGY | MELT FILTRATION
Right:
Laserfilter Twin from Erema
applications, Erema says that it uses the Laserfilter for even relatively clean applications such as PET bottle recy- cling. “By doing this we can reduce the material losses of a typical mesh screen filter from around 1.5-2.5% to values below 0.5%,” adds Obermayr. “In addition, due to its background and design the Laserfilter is a robust and reliable filter, which helps to reduce manual screen changes from one to three times per day for a mesh-screen filter to once every three to four weeks, or even up to three months depending on parameters, for a Laserfilter.” Erema adds that the Laserfilter-system is based
Above: Dr. Stephan Gneuss, Managing Director of Gneuss Kunststoff- technik
Right: Gneuss rotary filtration system
on fixed screens, meaning that there are no issues with rotating seals that only work under dynamic conditions and which always need close mainte- nance attention. This reliable and solid basic package can be adapted accordingly to many different applications. Melt filtration for recycling plastics requires consistent quality, economic efficiency and a high degree of flexibility with regard to changing input qualities, says Dr. Stephan Gneuss, Managing Director of Gneuss Kunststofftechnik. “The market is increasingly divided into two growing segments,” he adds. “Firstly, there are high quality materials from brand owner-controlled sourcing processes, where the drive is for optimised quality of the final recycled product, which is comparable to virgin material. However, there are also lower quality materials from various sources, where the drive is for optimised recycling processes that are able to handle larger amounts of impurities. “The trend of shifting materials from energetical
recycling – incineration – to physical recycling processes increases the amount of hard-to-recycle materials due to the mix of different polymers and the large amount of impurities. At the same time, large quantities of plastics waste that were previ- ously exported to Asia, now have to be recycled in Europe, which is stretching existing capacities. As a result, there is currently a demand for larger capacities, plus technical solutions for handling material mixes that were previously incinerated.” Gneuss highlights a main technical area of
interest at present in melt filtration as being high economic efficiency of the filtration process even with low quality input materials. This means optimised self-cleaning (back flushing) with
18 PLASTICS RECYCLING WORLD | March/April 2019
www.plasticsrecyclingworld.com
minimised material losses. In addition, there is a need for greater flexibility in the recycling process with regard to changing input qualities and output
requirements. Extrusion
processes are now being optimised with regard to decontamination, and control of intrinsic viscosity in the case of PET. The company
has recently designed and optimised filtration systems, extrusion systems and polycondensation systems for PET, which can take these
requirements into account. A number
of new products will be introduced at K 2019. Stephan Gneuss adds that the company has also been involved in a number of interesting bespoke recycling projects recently. These have included a food grade recycling process for very low quality PET bottle flakes, which previously could not be used for food contact applications. In addition, there was a project for recycling of PET industrial waste – POY fibres – enabling a zero waste production process. Post-consumer polystyrene waste for food grade applications has also been a recent recycling project challenge. “The recycling market is a fast moving and continuously changing market,” he says. “We have worked hard to develop new products and to adapt our existing product range for the needs of today – and we promise to continue doing so with regard to future market changes.” Ettlinger – part of the Maag Group – has developed the ECO melt filters that offer ultra-fine filtration to 60 microns. The company says that the
PHOTO: GNEUSS
PHOTO: GNEUSS
PHOTO: EREMA
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