New technology for beverage carton recycling

Europe – Paper producer Stora Enso and packaging manufacturer Tetra Pak have unveiled a new technology for recycling the plastic and aluminium from beverage cartons. The pyrolysis-based approach extends drink carton recycling beyond paperboard to the other 27% of the pack, it is claimed.

At a press conference held at the Stora Enso paper mill in Barcelona where the pyrolysis process has been put into action, Plant Manager Juan Vila explained that, unlike with previous technology used at a plant in Finland that failed for economic reasons, the new technique operates at a lower temperature (400 degC versus nearly 800 degC) and in a zero-oxygen chamber. ‘The other chamber had 10-15% oxygen and this created aluminium oxide which is worth much less than aluminium,’ he pointed out. The process begins with the polylaminate (plastic-aluminium mixture) that has been separated from the beverage carton paper in a pulping chamber that works much like a washing machine. This residue is dried and broken down into small pieces before being subjected to heat which causes the plastic to evaporate while the aluminium remains in place. The evaporated gas can be used to generate electricity and steam, and the aluminium can be recycled into new products. The process generates sufficient power from the evaporated plastic to satisfy 10% of the Barcelona paper mill’s energy requirements – and the reduced temperatures mean this can be achieved with a lower energy bill. With help and technical assistance from Tetra Pak, Stora Enso began operating the pyrolysis process this summer after having already run a pilot with an annual capacity of 1000 tonnes of beverage cartons. Newly-installed machinery will enable Stora Enso to move up to industrial-scale production next year, with a capacity to process 30 000 tonnes of used beverage cartons annually. Recycling International first reported on this new technology in October 2009.

www.storaenso.com