Waste tyres energy source

A promising and relatively new way to utilize both whole and processed old tyres (Fig. 1) is to recover the energy contained in this waste material. As an energy source, tyres represent an attractive alternative to other fuels due to their high heating value. On average, the... 

With regard to the recent waste tyre situation in Europe, by 2010 the European Tyre Rubber Manufacturers Association (ETRM A) was able to claim that the market for tyre-derived products was sustainable and economically viable and that the European recovery rate for end-of-life tyres had reached 96% [7]. In the same article the UK was reported as treating 100% of its end-of-life tyres. The figures that were included showed that of the 479,000 tonnes of end-of-life tyres arising in the UK during 2009, 8.5% were retreaded, 45.1% were processed into other materials, 24% were used as a source of energy, and 19% were re-used or exported. 

At pyrolysis temperatures (e.g., 800-1,200 °C) waste rubber (usually tyres that are either whole or shredded) can be reduced down to gas, oil, char, metal and inorganic fractions that, with further processing, can then be used as energy sources, or additives and starting materials for other products. 

A large number of waste tyres are incinerated in cement kilns to produce Portland cement because they are particularly well suited to being a source of energy for this particular application. The reason for this is that the kilns operate at very high temperatures (e.g., 2,000 °C) and this converts the steel in the whole tyres to iron oxide as well as recovering the zinc oxide from the rubber and creating CO2 and sulfur dioxide. The sulfur dioxide does not escape from the kiln, as it reacts with the calcium oxide present to form calcium sulfate. These... 

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