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Converting Laminates into Energy and Aluminium for.. (CLEAN)
Converting Laminates into Energy and Aluminium for the benefit of Nature
(CLEAN)
Start date: May 1, 2006,
End date: Apr 30, 2010
PROJECT
FINISHED
Background
In Europe, more than a million tonnes of drink cartons are thrown away after use every year. More and more of these drink cartons are now being recovered in various types of collection schemes (29% in 2004). The 300 000 tonnes recovered are processed in the paper industry, where the paper fibres (210 000 tons) are fully recycled into new paper products. However, the plastic-aluminium layers in the packaging of the drink cartons (more than 30% of the packaging) cannot be processed further which results in an annual solid waste stream of 90 000 tonnes that has to be disposed of, and it often ends up in a landfill.
âBrikâ packaging is widely used for food storage and delivery as it keeps food in a very good condition and its light weight makes it easy to transport and handle. In a drive to recycle these âbriksâ, initiatives have been undertaken to collect the empty cartons separately. The collected briks are typically sent to a paper factory that recycles their paper layers into new paper products. The briks, however, also consist of thin plastic-aluminium layers. These so-called laminates are useless for the paper factory and cannot be recycled. The papermill Stora Enso Barcelona and engineering firm Alucha launched the CLEAN project with the aim of developing a technology, and building and operating Europeâs first facility that can fully recycle brik cartons.
Objectives
The CLEAN project aimed to demonstrate a recycling solution for a specific type of solid municipal waste â plastic aluminium laminate, which comes from used drink cartons. Many years in development, a new technology is able to recycle the laminate waste by separating the aluminium for re-use in the aluminium industry and generating green electricity. The project planned to build and start operations of a demonstration facility to recycle this drink carton laminate waste on an industrial scale.
Results
The first step was to separate the cardboard. Although this operation was already being conducted in some paper mills, the project upscaled and optimised the process in a way that fosters the further recycling of the cardboard.
The solution found for the plastic-aluminium layer is based on the technical principle of a chemical process called pyrolisis. The CLEAN project takes the laminate residue from the paper factory and introduces it into a chamber. There, it is heated up in a controlled environment so that it does not burn. Instead, the heat causes the plastic to âevaporateâ and turn into a hot gas (decomposition of the organic matter into basic molecules), while the aluminium is unaffected. The hot gas is extracted from the chamber for further processing, while the aluminium comes out clean, ready to be reused.
After extracting the hot gas from the chamber, it is cooled down to room temperature. The cooling down process enables the gas to remain in its gaseous state (similar to LPG, Liquefied Petroleum Gas) while the other part becomes a liquid (similar to crude oil). Both gas and oil are energy-rich fuels. To make the process self-sustainable from an energy point of view, a small part of the oil and gas is used to heat up the pyrolisis chamber. The vast majority, however, is used to provide much-needed steam for the paper factory. As such, the recycled oils and gas save natural gas, which would otherwise be needed to make that steam.
The aluminium is left in the reactor as small flakes. These flakes are cooled down, cleaned-up (by filtering) and then compressed into briquettes. The beneficiary, PALWaste Recycling, intends to sell these aluminium briquettes back to the aluminium industry as a raw material. From an environmental point of view, this is very beneficial as the production of new aluminium is energy consuming.
The quantified results of the project:
The papermill now uses 50 000 tonnes/year of cardboard from PAL waste, which corresponds to nearly all the drink cartons recovered in Spain. In fact, the papermill uses drink carton waste from France as well as Spain;
The energy extracted from the hydrocarbon oils and gases (from the plastic layer after pyrolisis) is used to generate steam for the papermill. This will help to save 6 300 tonnes of natural gas;
The treatment process is self-sustainable from an energy point of view as it uses its own energy, except during start-up operation
Elimination of water consumption during the process;
Atmospheric emissions are carefully controlled by combustion at very high temperatures in order to ensure that only CO2 and water steam is released into the atmosphere;
The recovery of 1 260 tonnes/year of aluminium equates to a saving of 21 000 MWh per year, comparing it with the production of aluminium from the bauxite process. If this figure is converted into CO2, it corresponds to a reduction of 6 000 tonnes per year.
Around 50 000 tonnes of wet laminate waste is no longer sent to landfill, which means the saving of more than 1 500 lorry trips. If the average emissions by lorries is 2.68 kg CO2/km, and the landfill is 60 km away from the papermill, the reduction of CO2 emissions is around 250 tonnes/year.
The production of around 80 000 tonnes/year of steam at 6 bar.Recycling the laminates of the briks has several significant environmental benefits: prevention of dumping or burning of laminates; recovery of precious aluminium; recovery of plastics/fuels; and reduction of CO2 emissions. The CLEAN project has also helped close the recycling loop of briks, achieved economic savings and fostered new recycling initiatives.
The team will further study and develop energy production. While the beneficiary, SEBSA, currently uses the energy produced for steam production, the future may see alternative applications such as electricity generation and/or upgrading of the fuels to allow them to be used as a substitute/additive for diesel. The project innovation can be seen as a tool to be further developed both in terms of the wastes it treats and the fuels and applications it generates.
As a result of the recycling technologyâs success in dealing with waste on a large scale and its economical viability, the team is planning to apply it in other paper mills in Europe. Specifically, it foresees the construction of three plants in the next fives years.
Further information on the project can be found in the project's layman report and After-LIFE Communication Plan (see "Read more" section).