Every year in Europe about 480 000 tonnes of laminated glass waste results from end-of-life vehicles (ELVs). Laminated glass is about 3% of the total material of a vehicle. Currently, most of this glass is incinerated or buried and only a fraction is recycled. Polyvinyl butyral (PVB) is a resin used for applications that require strong binding, including the production of laminated glass in automobile windscreens. Current efforts to recycle PVB from the windshields of ELVs have had limited success, as the technologies used do not purify the plastic sufficiently. This lack of purity means that it has only been possible to use recycled PVB in low-quality applications, such as tiles, carpets, sound insulation and mixing with bitumen.
The Recycled - PVB project aimed to develop a pilot plant for the purification of PVB from laminated glass. The overall objective was to help find a practical and sustainable use for waste glass from vehicles. The project planned to further knowledge about the specific equipment and technical characteristics required for the washing, grinding and processing PVB. It also aimed to examine the requirements of PVB within the automotive and building sectors, among others. Based on laboratory work, the project would define and develop a coherent process at semi-industrial scale to obtain PVB from recycled laminated glass. The plant was expected to be operated at a production scale of 20 kg of recycled PVB per hour. The project hoped to show the technical and economic feasibility of both PVB recycling and its subsequent use in manufacturing laminated glass. The target was to achieve costs of only €4 or €5 per kg of recycled PVB, compared to the current industrial costs of between €9 and €13 per kg. The costs of ELV storage and disposal would also be reduced. The environmental benefits would include a reduction in the amount of material sent to landfill, reduced GHG emissions from incineration of waste PVB, and reduced demand for virgin PVB with its associated lifecycle environmental impact. In this way, the project would contribute to the European Directive 2000/53/EC, which targets 95% recovery of ELVs by 2015.
The RECYCLED-PVB project constructed and ran a demonstration pilot plant for the recycling of the Polivinil Butiral (PVB) from laminated glass used in the car and building industries with a recycling capacity of around 20 kg/h.
During the first months of the project the beneficiaries carried out a series of tasks in order to establish the requirements of the product and the process. These include conducting a market survey of the recycled PVB, producing a flow chart of the main activities of the recycling process and carrying out a Life Cycle Analysis of the residual and the recycled PVB.
The project team then started to design and construct the three modules of the plant. After carrying out an exhaustive study of the most suitable machinery and numerous tests of the different devices available in the market, the team designed an extraction-separation module with the aim of achieving the maximum mechanical separation of the PVB and the glass. Once the design was completed, the necessary equipment was purchased and the required modifications were made to achieve the highest productivity.
For the purification module, the first step was to define the characteristics, requirements and parameters to be monitored. Once the design was finished, the information was transmitted to several providers that developed different bids. The beneficiaries selected the best one and the purification module was constructed under the specifications and requirements established to reach optimal purification and recycling of post-consumer PVB from the extraction-separation module.
Completing the process module required the carrying out of lab tests of used PVB. Flakes of recycled PVB were used to make PVB plates, which were then tested. Results showed that they had similar properties to commercial PVB. The most suitable option from a technical/economic point of view was established and equipment obtained (the best being that which already belonged to the foundation).
Once the three modules were assembled, the beneficiaries tested the pilot plant using material from two different sources: automotive and building industries. These tests identified several necessary modifications that needed to be made in order to optimise the process.
The developed process has a great potential. A high number of companies have contacted the beneficiaries. Moreover, the beneficiaries have held several meetings with representatives of the regional government of Navarra in order to disseminate the project results.
Due to the current economic crisis, however, the authorities are not willing to approve legal initiatives that involve new costs for the companies and thus make recycling more economically attractive. But beneficiaries have reached an agreement with a glass recycler from France to treat its waste. Although the treatment capacity of the pilot plant is limited, this agreement will assure the continuity of the project aims after its end.