The Environmental Research Group works in this field with real waste, such as used tyres and plastic, to create new products through the pirolisis process. This research field is part of the “cycle economy,” a concept that seeks to generate a physical product by reusing the resources of others, which is also part of the 12th Sustainable Development Goals (UE): responsible production and consumption.
The Pirolisis procedure
The group employs pirolisis to give these tyres and plastics a second chance. The pirolisis process involves applying temperatures ranging from 400°C to 600°C in an oxygen-free environment. This particular circumstance allows for the avoidance of combustion and the production of one or more new products.
Pirolisis can recover the original material, styrene, from plastics that are mostly made of polystyrene. The main goal in the case of other plastics is to obtain a mixture of hydrocarbons that can then be used in the petrochemical industry or directly as fuel.
In the tyres:
In the case of tyres, three different products are the result of pyrolysis: energy for self-supplying the reactor; pyrolytic carbon black, which can be used in the manufacture of new tyres; and liquid hydrocarbons.
The pyrolytic liquid is a mixture of various hydrocarbons, including linear, branched, naphthenic, and aromatic compounds. Distilling this liquid yields a light fraction rich in benzene, toluene, ethylbenzene, and limonene, as well as a heavy fraction. The light fraction can be used to make solvent chemicals, while the heavy fraction can be used to make new carbon black.
The GIM is currently participating in the BLACKCYCLE project (For the circular economy of tyre domain: recycling end of life tyres into new tyres) coordinated by Michelin, which aims to produce new tyres by incorporating carbon black produced from used tyres.