Scrap tyre stockpiles could soon be a thing of the past thanks to Green Distillation Technologies (GDT), a tyre recycling company that developed a process for extracting oil from old tyres.
A team of mechanical engineers from the Queensland University of Technology (QUT) recently tested the oil extracted from old tyres at QUT’s Biofuel Engine Research Facility.
The QUT engineering team, consisting of QUT’s Professor Richard Brown, PhD student Farhad Hossain, process engineer Dr Tom Rainey and air-quality expert Professor Zoran Ristovski, performed rigorous tests on the oil to determine its emissions and output.
Mr Farhad said that when the oil was blended with diesel it was found to produce a fuel with reduced emissions and no loss of engine performance.
“We tested the oil which GDT produces from both recycled natural and synthetic rubber tyres in 10 per cent and 20 per cent diesel blends,” Mr Farhad said.
“We tested the tyre oil blends in a turbocharged, common rail, direct injection, six-cylinder engine in the Biofuel Engine Research Facility at QUT. The engine is typical of engine types used in the transport industry.”
He said the experiments were performed with a constant speed and four different engine loads of 25, 50, 75 and 100 per cent of full load.
“We found a 30 per cent reduction in nitrogen oxide which contributes to photochemical smog, and lower particle mass which means fewer problems for emission treatment systems,” Mr Farhad added.
GDT Chief Operating Officer Trevor Bayley said the oil could also be further refined into automotive or aviation jet fuel or be used as a heating fuel.
“The process recycles end-of-life tyres into oil, carbon and steel, leaving nothing wasted and even uses some of the recovered oil as the heat source. Carbon is the most common recovered ingredient and the steel rim and framework is the third most common ingredient, while the oil is the most valuable,” Mr Bayley said.
“We are delighted at the findings of the QUT research as it will help us promote the sustainable use for end-of-life tyres. The potential of this source of biofuel feedstock is immense, and it is more sustainable than other bio-oils from plants such as corn, or algae.”
According to him, a recycled 10kg car tyre yields 4 litres of oil, 1.5kg of steel and 4 kg of oil, and a 70kg truck tyre provides 28 litres of oil, 11kg of steel and 28kg of carbon.
“GDT plans to have the first fully operational commercial plant delivering eight million litres of oil a year from mid-2017, followed by a world-first mining tyre processing plant in either Qld or WA,” Mr Bayley concluded.
Globally, 1.5 billion tonnes of tyres are discarded each year. It is estimated that Australia alone will generate 55 million disused tyres a year by 2020.