Researchers turn plastic waste into jet fuel

Plastic trash may one day help people fly as researchers have found a way to turn daily plastic waste products into jet fuel.

"There is a lot of hydrogen in plastics, which is a key component in fuel," said Hanwu Lei, Associate Professor at the Washington State University in the US.

To produce jet fuel, the researchers melted plastic waste at high temperature with activated carbon.

"This is a very good, and relatively simple, way to recycle these plastics," Lei said.

For the study, the research team tested low-density polyethylene and mixed a variety of waste plastic products like water bottles, milk bottles, plastic bags and ground them down to around three millimetres, or about the size of a grain of rice.

During the research, the plastic granules were then placed on top of activated carbon in a tube reactor at a high temperature, ranging from 430 degree Celsius to 571 degrees Celsius.

The carbon is a catalyst or a substance that speeds up a chemical reaction without being consumed by the reaction.

"Plastic is hard to break down. You have to add a catalyst to help break the chemical bonds," Lei said.

After testing several different catalysts at different temperatures, the best result they had produced a mixture of 85 per cent jet fuel and 15 per cent diesel fuel, said the study published in the journal Applied Energy.

"We can recover almost 100 per cent of the energy from the plastic we tested, the fuel is very good quality, and the byproduct gasses produced are high quality and useful as well," Lei said.

"You have to separate the resulting product to get jet fuel, if you don't separate it, then it's all diesel fuel," Lei added.

At least 4.8 million tonnes of plastic enters the ocean each year worldwide, according to conservative estimates by scientists.

The new process shows promise in reducing that waste.