Optimising PET recycling

Working with the Bühler Technology Group, Schmalbach-Lubeca has developed a new recycling system for the production of new beverage bottles from post-consumer PET containers.

The new recycling system will be commissioned in the Beaune recycling plant of Schmalbach-Lubeca AG in late 2002. Roughly DM10m is earmarked for investment.

'For our customers, the improved process has the advantage that recycled PET pellets can now be offered at an even more attractive price than before, and that they are of equivalent quality to virgin material,' says Floyd Flexon, Vice President Environment and Recycling of Schmalbach-Lubeca's Product Group PET Containers Europe/Asia.

Schmalbach-Lubeca developed its Supercycle technology in 1990. It allows post-consumer PET bottles to be turned into food-grade PET pellets in a two-stage process. The new optimised Supercycling process, however, is based on Bühler's bottle-to-bottle recycling technology, and has the advantage that two previously separate function steps were combined and blended into one continuous process:

The first step in the process uses a ring extruder, where the post-consumer PET material is dried and freed completely from any organic impurities, such as flavours. Then, in a continuous solid state polycondensation (SSP) process, the polyester is refined to plastic pellets of greater material strength and thus gets the same properties as virgin PET pellets.

The combination of these two functions increases output and reduces both energy consumption and production cost at the same time. In addition, the process is particularly environmentally friendly, since it is based exclusively on thermal and mechanical process stages without the need for chemical treatment of the material.

'The cooperation with Bühler has brought about a breakthrough in the optimisation of the Supercycle technology. Each company has contributed its specific know-how and core competence. The benefits of the process will turn bottle-to-bottle recycling into an integral part of PET bottle production', Flexon said.

The sales volume of PET containers in Europe is anticipated to rise from 1.3 million tons in 1999 to 2 million tons in 2004. Over the same period, the volume of post-consumer PET containers collected is forecast to grow from 210,000 to 504,000 tons.