The groundbreaking new technique can turn plastic waste into energy-dense fuel

The world has plastic problem. According to the United Nations, more than 8 million tonnes plastic enters the oceans every year.

How to get rid of this problem has been the subject of much research. In order to help stain plastic clogged waterways from the sky, everything from reducing plastic use to packaging to using drones was emphasized. But researchers from Purdue University have a different idea: they want to turn it into fuel.

To achieve this, they pioneered a new process of chemical transformation, which is capable of converting more than 90 percent of the polyolefin waste, the polymer behind the widely used plastic polyethylene, to high-quality gasoline or diesel-like fuel. The results can be the rule-changer for mankind.

“We have developed a method to convert polyolefin waste, which include Type 2 (HDPE), Type 4 (LDPE and LLDPE), and Type 5 (PP), into various useful products,” “The conversion is achieved using subcritical or supercritical water, which can convert plastic waste into oil, fuels, or gas, depending on the processing conditions. Some impurities in the plastic waste is converted into oil or extracted into the processing water. Both conversion and extraction are achieved in the same process.” - Nien-Hwa Linda Wang, professor in Purdue University

The researchers warmed the water to high temperatures of approximately 850 degrees Fahrenheit under high pressure to perform its operations. When the purified plastic waste was added to the supercritical water, it turned into oil after an hour of operation.

Wang said he saw no reason why this laboratory demonstration should not be transformed into an economic wide process - even if there was not a lot to do.

“We have [had] great success for converting polyolefin waste,” Wang said. “Further research is still needed to produce higher quality products with lower processing costs for the polyolefin waste. We have not yet had any research funding to test this technology for converting other types of plastic waste or for converting complex waste mixtures. We hope to raise funding to test this technology at a pilot scale. Successful results at pilot scale will motivate industry to commercialize this technology.”

Credit: https://pubs.acs.org/doi/10.1021/acssuschemeng.8b03841