Researchers from Purdue University in the US developed a new chemical conversion process that can transform polyolefin waste, a form of plastic, into high-quality fuels and other items.

The United Nations estimates that more than 8 million tons of plastic end up into the ocean each year. This plastic breaks down into microplastics and is nearly impossible to clean up.

The process was developed by Professor Linda Wang, graduate student Kai Jin and postdoctoral researcher Wan-Tin (Grace) Chen. The technique can transform more than 90 per cent of polyolefin waste, like HDPE, (L)LDPE and PP, into different products, including pure polymers, naphtha, fuels and monomers.

The conversion process is achieved by using supercritical water, which is water that is held by pressure at a temperature higher than its natural boiling point. Once the plastic is converted into naphtha it can be used as a feedstock for other chemicals or further separated into specialty solvents or other products. Some impurities are converted into oil or extracted into the processing water.

The fuels derived from polyolefin waste generated each year could satisfy 4 per cent of the annual demand for gasoline and diesel fuels.

The laboratory demonstration could be turned into an economical large-scale process, once they collect the necessary funding for a pilot scale.

Photos: Purdue University / Vincent Walter