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When tires reach the end of the road, they often wind polluting the environment in landfills. In Europe alone, 3 million tons of tires are produced each year – and 60-70% of them are dumpstered. To take advantage of this untapped resource the EU has created the TyGRe Project, which is researching ways that old tires can be turned into new sources of synthetic fuel and precursors to electronic components.
The TyGRe Project is currently investigating the best ways to produce silicon carbide and synthesis gas, or “syngas” from old tires. The experiments are being carried out by the Italian National Agency for New Technologies, Energy and Sustainable Economic Development, (ENEA) in Portici.
To recycle the tires, scrap is heated in a reactor along with steam at 1,000 degrees Celsius. Most of the energy required to heat the scrap can be provided by captured syngas, which is composed of hydrogen, carbon monoxide and dioxide, and methane. The resulting product can be used as fuel, as it has a similar heat capacity to that of natural gas. Other by-products created by the gasification of the tires include solid carbon, which can be turned into silicon carbide by introducing it to silicon oxide at high temperatures. Solid silicon carbide is a valuable material for ceramic and electronic manufacturing, and it is normally very expensive to create.
A prototype recycling plant is now under construction at the ENEA facilities in Trisaia, Italy and it should be up and running by the end of March. It is expected to process about 30kg of tire waste every hour, and it will be an experimental model for future tire recycling operations.