New technology to convert plastic and tyres to diesel fuel


Monash University chemical engineer Professor Sankar Bhattacharya has built a prototype processing plant that turns plastic and waste tyres into diesel fuel.

“The majority of the plastics we use in our daily life – different grades of polyethylene, polypropylene, polystyrene and even polyvinyl chloride, to some extent – can be processed into liquid fuel,” he said.

Turning plastic back into fuel is relatively environmentally friendly. The high-temperature catalytic process operates at temperatures around 400 degrees Celsius, and this requires energy input. Sorting and cleaning the waste uses water, while gaseous emissions produced as a by-product include carbon dioxide.

Professor Bhattacharya said that some of the combustible gases produced during the processing of the waste plastics are effectively recycled back to sustain the process.

Professor Bhattacharya, who came to Monash University after a career commissioning coal-fired power plants and gasification plants, is planning to develop the technology into one or more full-scale processing plants that can start taking recyclables as soon as possible.

He is currently having discussions with three councils that border the University to scale up his laboratory processing facility into a plant that can handle real-world waste streams. His team has collected statistics on the volume of waste generated by the councils.

“It’s definitely possible to build three 10-tonne-per-day or one 30-tonne-per-day plant on the land which is owned by any one of the three councils,” he says.

He and his team have built a business case to obtain venture capital funding.

“We did a generalised techno-economic analysis, including the capital costs of such a plant, all the control systems that will be necessary to run it, the manpower for three shifts on a day in, day out basis, the purchase of the feedstock supply,” he said. “Within two to five years, depending on the initial price of the plant that will be built, it will have a net positive value.”

In addition to plastics, the developed technology can also be tweaked to process waste tyres into fuel. Tyres are a huge waste issue in Australia; for example, in 2013-2014, 51 million equivalent passenger units (1EPU = 8kg) of tyres ended up in the waste stream. According to the latest report, only 5 per cent of these are recycled locally, the rest going to landfill, stockpile and illegal dumping.

Professor Bhattacharya’s team has collaborated with industry on processing of waste tyres to fuel, and electronic waste for high-value metal recovery using non-toxic ingredients.

Processing plastic and tyre waste into fuel at home would be an environmental win-win for Australia. Not only could we keep these items out of the landfill, but we could also at the same time reduce our dependence on extracted and imported fossil fuels.

“We have the opportunity here to showcase our capacity and expertise in the processing of waste tyres as well as waste plastics – right now. We can scale them up easily,” he said.

“If everything falls into place, we start the work and within one year we have a plant built here – subject, of course, to EPA approval, land availability and all those kinds of things. But, really, it can be done that quickly.”