Every year around 48 million tyres are discarded in Australia, and many end up as landfill or are stockpiled, exported and illegally dumped. This can have a significant impact on people’s health and the environment.
But a new process being proposed by a Victorian company could break down tyres in a 100 per cent recycling process.
The main part of the process is pyrolysis, which Used Tyre Recycling Corporation (UTRC) is looking to use at a new plant in Victoria.
Vincent Wong, CTO at UTRC, has been working on the process for seven to eight years, initially at a Canadian company.
“It is quite complicated compared to all the existing processes that help people break down tyres – no doubt. It is a chemical process and it often requires a lot of chemical engineering,” Wong said.
“What we’re trying to do is transform waste tyres back to their original materials that can be used for different applications.”
The first step of the process involves shredding the tyres into smaller pieces. The next step, the pyrolysis, involves a chamber that heats the shredded rubber up to a few hundred degrees centigrade. The tyres are then broken down into heavy oil, carbon black, steel wire, and some fabric.
Next, carbon black powder milling refines the carbon black into a very small size. A carbon black pelletising plant then converts the fine powder into pellets to make it easier to store and export. Finally, an oil distillation plant refines the heavy oil to gasoline and diesel.
“We refine the carbon black for a fine grade that can be used in plastic and rubber industries,” Wong said.
“Meanwhile, the oil that we recover goes through a distillation process to turn it into a few components. The lighter oil is gasoline, followed by diesel with a little bit of heavy oil.”
Sulphur compounds, which are recovered during the process, will be dealt with in several ways by UTRC. Some sulphur will remain in the carbon black, while sulphur compounds in the oil will be scrubbed to form a non-harmful material, such as sodium sulphate, which can be disposed off.
UTRC has several patents relating to the process’ products and application, which it obtained from a Canadian company Wong was working for. It also has a pending patent for using the oil to make virgin carbon black.
Tyre pyrolysis compares to more traditional methods of tyre decomposition that are used in Australia, such as turning tyres into crumb rubber for carpet backing, rubber mats, sport fields and civil engineering applications. But Wong said these types of applications are limited.
“So the bottom line is that at the end of their life, you still have to get rid of the rubber. There is not a complete recycling process at the end,” Wong said.
Wong said pyrolysis is one of the most effective methods of dealing with unused tyres because it physically breaks down the entire product. He also said previous failures to utilise the process was due to poor design; not meeting product specifications; a lack of technical marketing and support; and a lack of promotion and incentives from the government.
The processing plant is expected to yield around 40 to 45 per cent in carbon black; 30 to 40 per cent in oil; and 10 to 15 per cent in steel. Around 5 per cent of the gas produced will be used to run the process.
In practical numbers, 1,000kgs of tyres can yield 450kgs in fuels; 350kg in black carbon powder; and 130kgs in steel/metals.
The company has lodged applications and approvals with the local council in Stawell, Victoria, to build the plant. Wong said the plant’s engineering design is critical to ensuring UTRC meets the EPA Works Permit, as well as other relevant codes and standards.
“Equipment installation and commission, design, contract and the permit takes about six months, followed by installation for around three to four months and around two to three months for commissioning equipment,” Wong said.
The council approval process could take up to six months, but Wong is hopeful commissioning of the plant will begin by June or July next year.
In the meantime, Wong has been continuing with research and development for product applications.
“UTRC is in the process of going through some funding and grant applications with the government and also with universities on research and development work,” he said.
“We want to use the carbon black that we produce and see what other new applications that we can use it for in different fields and different areas. The research and development work will not stop.”