The scale of the problem that scrap tyres now presents to the environment is summed up by a couple of simple facts. In the USA alone, an amazing 300 million tyres are dumped each and every year while, according to some estimates, there are as many scrap tyres are there are people on earth.
It’s bad enough that this mass of ugly rubber is defacing rivers, rubbish dumps and industrial parks around the world. But making the matter even worse, it’s an environmental disaster because tyres are not biodegradable.
For obvious reasons then, the tyre recycling industry has become an extremely important one, generating multi-millions of dollars each year. It is an industry that is set to grew even more dramatically in the years ahead.
The prime method of ‘recycling’ tyres for many years was to burn them, but this caused huge environmental problems too, with dangerous and toxic smoke and fumes. The good news, however, is that today tyre recycling is being conducted in a much more cost effective and scientific way thanks to modern new techniques.
Popular tyre recycling solutions include reconstituting the rubber as shoes, road safety barriers, floating pontoons at sea or even basketball court surfaces. When it comes to environmental friendliness, however, by far the most effective technique is a process known as tyre pyrolysis.
Tyre pyrolysis is a process through which scrap tyres can be converted into a range of products, including low grade carbon and a solid residue named char, as well as fuel gas and oils. The process is remarkably simple.
Scrap tyres that have been shredded or inserted whole, are subjected to extremely high temperatures inside a specially-designed, oxygen-free reactor vessel. The tyres soften and break down, eventually turning into vapour which can be used in several ways, including as a condensed fuel oil or a flammable vapour. Any molecules that don’t condense during the process can be used as another form of gas.
Around four tenths of the scrap tyre’s weight will remain in a sold state, which can also be used for fuel purposes, either as char or a low grade carbon. From an environmental perspective, what’s particularly attractive about tyre pyrolysis is that it has almost no waste or emissions.
Operating a pyrolysis chamber is an extremely technical job. It can take anything between five minutes and five hours for the process to finish depending on the method being used and the type of tyre being broken down in the chamber. Temperatures can range between 400 and 900 degrees centigrade during this time with the solid state carbon and char sometimes taking 24 hours to cool down and harden afterwards.
The problem of scrap tyres is going to get worse instead of better, especially as the new superpowers of India and China grow industrially. So there’s no question that tyre recycling options with the kind of efficient and environmentally-friendly solutions that tyre pyrolysis offer are going to become increasingly popular.
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