Bühler solution helps PET recycler improve yield of bottle-to-bottle grade rPET flakes by more than 30 percent

At K 2016 (the world's largest trade show focused on plastics and rubber, held October 19-26 in Germany) the Bühler Group revealed how its two-machine solution – the SORTEX E PolyVision and SORTEX A ColorVision – can deliver bottle-to-bottle grade rPET flakes at the highest yield, currently possible in the market. According to Bühler, STF Recycling GmbH, one of the largest recyclers in Europe, has very positive things to say about the company's flexible SORTEX system. STF says SORTEX enables them to achieve higher value recyclate and profit margins, by accurately separating valuable rPET from baled material. It can do this regardless of its composition and contamination level, which can vary from as little as 5 percent to as much as 30 percent, from bale to bale, depending on the recycling practises of different countries.

STF Recycling GmbH recently chose Bühler’s two-machine solution to achieve a higher grade rPET which can be re-used in the bottle-to-bottle industry. Mr Söllner from STF applauded Bühler for its ability to remove foreign materials (FM) that can devalue rPET, such as opaque defects, wood, metals, other FM and non-PET. Speaking about the solution, Mr Söllner said: “We chose to use SORTEX as it is the best flake sorter in the market. Bühler has also introduced us to its partner, US-based National Recovery Technologies (NRT), which is now supplying us with bottle sorters, at the front end of our production line.”

The two-machine solution incorporates the SORTEX A ColorVision, which delivers superior colour sorting thanks to its use of three visible wavelengths, allowing for excellent colour detection. When combined with enhanced InGaAs camera technology, an advanced inspection system and SmartEject technology, the sorter efficiently removes challenging foreign material from clear, blue, green and jazz applications. Then the SORTEX E PolyVision employs a revolutionary polymer sorting process, using a unique combination of transparent and reflective sorting, simultaneously. This identifies invisible and same-colour polymer contaminants by their unique chemical signature, successfully separating clear polymers from clear PET. This combination delivers higher grade rPET flakes that exceed the minimum standards for re-use.

Mr Söllner added: “PET recycling is a very complex multistage process that requires efficiency at every point. Our ultimate aim is to continue to increase output quality, while at the same time minimizing the loss of valuable and re-usable product in the reject stream. We undertook several industry trials to evaluate other technologies on the market but discovered that Bühler provided the best solution. First class machine results combined with impressive customer service and a commitment to ongoing development meant it was the only optical sorting solution for us. We highly recommend Bühler’s SORTEX technology.”

Since its launch, Bühler says their two-machine solution has rapidly gained market acceptance and industry recognition from recyclers and OEM’s, as a ground breaking development in FM sorting, particularly with its capability to identify difficult to detect polymers. Not only does it complete the company’s rPET sorting portfolio, but it positions the business as a leading supplier for colour, FM and polymer removal. In just five months, it has been sold to factories across Europe and North America. Further installations, similar to the one in STF Recycling, are expected to be confirmed in 2017.

STF Recycling processes 130,000 tonnes of PET bottles each year, from which it makes rPET flakes and pellets that are bottle-to-bottle grade. One of the biggest challenges faced by the company is the constantly changing input composition of materials to be sorted and recycled, with ever narrower output specifications. This includes more metals from beverage cans, as well as bottles with multilayers, sleeves and labels from PVC, PS, PC and PET-G plastics. The company, which has installed over 70 turnkey plants worldwide, has now integrated Bühler’s two-machine solution into its portfolio, enhancing its own offering.