Environment

Old tires find new life as cleaner alternative to diesel

Old tires find new life as cle...
Scrap tires could still help get you around with recycling technology that produces into saleable oil, carbon and steel
Scrap tires could still help get you around with recycling technology that produces into saleable oil, carbon and steel
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This table shows how much oil, steel and carbon QDT can get from individual tires
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This table shows how much oil, steel and carbon QDT can get from individual tires
Scrap tires could still help get you around with recycling technology that produces into saleable oil, carbon and steel
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Scrap tires could still help get you around with recycling technology that produces into saleable oil, carbon and steel

One is an eyesore and a health hazard, the other one is plain dirty. So what do you get when you combine processed scrap tires with diesel fuel? In what might be a case of two wrongs making a right, Australian startup Green Distillation Technologies (GDT) has shown that it is possible to get a cleaner blend of fuel by combining oil derived from old tires with diesel.

Recent attempts to recycle old tires have included coming up with a more energy-efficient way to break them down, using them as mosquito traps and cutting them up so they can be stored more easily. Despite these and various legislative efforts to minimize the hazards posed by scrap tires, they are incredibly hard to get rid of and there are still more of them than people know what to do with. In Australia alone, nearly 48 million end-of-life tires get discarded every year and most end up in landfills and illegal stockpiles.

GDT, which was launched in 2009, has pioneered a recycling technology that it calls destructive distillation to solve this problem. Similar to pyrolysis – the process by which organic materials are broken down by high heat in an oxygen-deprived environment – it reduces whole tires into saleable oil, carbon and steel.

It differs from other recycling methods in that it is the only process in Australia at the moment that turns the rubber from these tires into a different form of energy. Others merely change the shape or appearance of the rubber, points out GDT chief executive Craig Dunn. Apart from heat, the process is emission- and waste-free, and since it processes whole tires, no labor or energy is needed to break them down.

This table shows how much oil, steel and carbon QDT can get from individual tires
This table shows how much oil, steel and carbon QDT can get from individual tires

While this all sounds well and good in theory, how exactly does the oil produced measure up? According to engineers from the Queensland University of Technology (QUT) who subjected it to a series of rigorous tests, the results are highly promising: not only did it produce a fuel with reduced emissions, there was also no loss of engine performance when blended with diesel.

"We tested the oil which GDT produces from both recycled natural and synthetic rubber tires in 10 percent and 20 percent diesel blends," says Farhad Hossain, a doctoral candidate at QUT who was part of the study, adding that the tire-oil blends were tested in a turbocharged, common rail, direct injection, six-cylinder engine – typical engine types used in the transport industry. "Our experiments were performed with a constant speed and four different engine loads of 25, 50, 75 and 100 per cent of full load."

The researchers found a 30 percent reduction in nitrogen oxide, a greenhouse gas and air pollutant, as well as lower particle mass, which means fewer problems for emission treatment systems. In addition, the oil can also be used as a heating fuel, which is what happens at GDT's facility, and further refined into automotive or aviation jet fuel.

"The process recycles end-of-life tires into oil, carbon and steel, leaving nothing wasted," says GDT chief operating officer Trevor Bayley. "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."

While one might question whether a 30 percent reduction in pollutants is enough, the fact that the process helps cities get rid of end-of-life matter in an environmentally sustainable manner is a step forward at least.

GDT, which won a bronze award in the resource management or renewable resources category at the Edison Awards last year, has already received offers from at least one company to buy all the eight million liters of oil it will produce at its plant in Warren when it becomes fully operational next year, says Bayley. It is expected to process about 685,000 (19,000 tons) car and truck tires a year – approximately three percent of what ends up being discarded each year.

Talks to build a plant in Tasmania, which currently has 900,000 tires waiting to be processed, are still ongoing, and a mining tire processing plant is also planned for either Queensland or Western Australia.

Source: QUT

10 comments
watersworm
Love the recycling into oil AND steel AND carbon, no wasre from the waste ! How "carbon" is being reused ?
lisalee
@watersworm High purity carbon powder has numerous industrial applications eg. in nuclear reactors, electrochemical systems etc. Suffice it to say there is a demand for this stuff!
Mzungu_Mkubwa
@watersworm, I'm sure all the carbon is being sequestered deep in the earth lest it escape into our atmosphere and kill us all! (j/k) Love these kinds of efforts, but the article is still a little vague on the environmental impact of its operation.
Alien
Assuming that the enerygy input required is less than the energy output obtained and subject to the necessary capital cost of the plant, this sounds absolutely brilliant. Presuming the above to be cost effective, surely the process should be licensed for use worldwide with excellent rolyalty income for GDT as the developers.
DavidRogerBrown
Sounds really promising and a win-win situation. How much energy does it use in the process? Would get rid of tons of mosquitoes & big eye sores world wide at the same time!
Bob Flint
What is the cost to separate & re-use?
habakak
'...Apart from heat, the process is emission- and waste-free, and since it processes whole tires, no labor or energy is needed to break them down...' No energy is needed????? Maybe the process is energy neutral considering the fuel being extracted from the process, but it sounds like the process is fueled for free! I wish them all the best because it does sound like a good solution to the mountains of tires we discard annually around the world.
Eager-one
Before I retired from banking, I was invited to finance a plant to do just what is being described here. It is simple technology and the oil recovered from the tires (remember, they are made from oil, not rubber) fueled the process. The problem was what to do with the carbon black that resulted. No market for it then (1998). An effort was made to make it into a soil conditioner in Greece, but no deal.
Michael Z. Williamson
Thermodepolymerization of anything organic has been around for a decade. This is one refinement for a specific material, but it can be done with anything. The energy used in the process is less than the energy yielded from the fuel, so the process has a net positive yield. The energy isn't free, it's just part of the product.
mdr
Projected cost of production per litter in a large scale plant?