Energy

Chemical process converts plastic into jet fuel ingredients in an hour

Chemical process converts plas...
Researchers Hongfei Lin and Chuhua Jia have developed a new technique for recycling plastics, which reduces it to the building blocks for jet fuel and other products
Researchers Hongfei Lin and Chuhua Jia have developed a new technique for recycling plastics, which reduces it to the building blocks for jet fuel and other products
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Researchers Hongfei Lin and Chuhua Jia have developed a new technique for recycling plastics, which reduces it to the building blocks for jet fuel and other products
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Researchers Hongfei Lin and Chuhua Jia have developed a new technique for recycling plastics, which reduces it to the building blocks for jet fuel and other products

While millions of tons of plastic are produced in the US each year, only around 9 percent is recycled, and that is largely due to the difficulties around reducing the material to useful building blocks for other products. A new chemical treatment developed by scientists at Washington State University (WSU) could help chip away at this problem – a treatment that's been demonstrated by turning the most commonly used plastic into jet fuel components within one hour.

The idea of using chemical reactions to convert plastics into the building blocks for jet fuel and similar products is one scientists have been exploring for some time. By taking the material and combining it with catalysts under high temperatures, it can be reduced to organic compounds called hydrocarbons, which are made up of hydrogen and carbon and act as the building blocks for different types of fuel.

Where this latest study breaks new ground is in the relatively moderate temperatures and short timeframe required to carry out this process. The WSU researchers were experimenting with the catalysts and conditions needed to convert polyethylene, the plastic used in everything from shopping bags to shampoo bottles, into hydrocarbons, and have come up with a new methodology.

Using a catalyst made from carbon and the silvery-white metal ruthenium, along with some commonly used solvents, the scientists were able to convert around 90 percent of the plastic into the components for jet fuel, and other hydrocarbons, within one hour. This took place at around 220 °C (428 °F), much friendlier – and more economically viable – conditions than the temperatures required for a similar process we looked at in 2019, of around 500 °C (932 °F).

“Before the experiment, we only speculated but didn’t know if it would work,” says study author Chuhua Jia. “The result was so good.”

Through their experimentation, the team found the process could be tweaked to produce building blocks for other high-value products, such as lubricants. This involved simply altering the temperature, the amount of catalyst used or the timeframe to change the end result.

“Depending on the market, they can tune to what product they want to generate,” says study author Hongfei Lin. “They have flexibility. The application of this efficient process may provide a promising approach for selectively producing high-value products from waste polyethylene.”

The researchers are now working to scale up this process with an eye on commercializing the technology, and hope to adapt it to tackle other forms of plastic waste.

“In the recycling industry, the cost of recycling is key,” Lin said. “This work is a milestone for us to advance this new technology to commercialization.”

The research was published in the journal Chem Catalysis.

Source: Washington State University

6 comments
6 comments
DaveWesely
Plastic is a stable form of solid carbon. If you put it in a landfill, it is a form of carbon sequestration. If you turn it into liquid hydrocarbon, it gets burned and turned into carbon dioxide, adding to the climate emergency.
Recycling plastic is a joke. This method may work better, but how does it handle paper, inks and mixed plastics? More importantly, is it worth the effort?
Username
The solution to reducing pollution is not to turn it into a different form of pollution.
TechGazer
The simple hydrocarbons produced this way can also be feedstock for fresh polymers, so it doesn't have to be burned as fuel. The process might have a problem with mixed waste, but a cheap process for converting separated waste to valuable hydrocarbons would raise the price of separated plastic, making it worthwhile for someone to make that happen. So yes, I think this process has good potential.
Karmudjun
Thanks Nick, once again an informative synopsis.
I know the US holds a good supply of this rare ruthenium, but is it the best use of the platinum like metal? Of course, anything to reduce our PE waste across the globe and in the ocean, keeping it out of our air and food supply is a benefit to humankind. At least, to thinking humankind.
More significantly than the actual paper with proof of concept is the breakthrough in time and energy required to release the hydrocarbons from the structure. Plus their findings that they can produce all aspects of hydrocarbons means our electric cars may be lubricated by recycled plastic bags. Is it worth our effort? Eat plastic or reuse plastic is the real question.
mikewax
sounds like a win-win situation to me. Less crude comin outa the ground, less plastic goin into the sea. IF, that is, it takes less energy to produce your fuel this way, which it probably does. The plastic, after all, IS being collected, even if it's only for political reasons.
PeteB
Most researchers start by 'cracking' polyethylene into fuel or feedstock. This is already done commercially, with or without catalysts (kaolin is cheaper than ruthenium). The real challenge is dirty mixed waste plastics, I would like to see university researchers working with a clean 50:50 mix of polyester and polyamide instead of revisiting LDPE.