Researchers Turn Plastic to Jet Fuel, Making Recycling Easier

Scientists say they have developed a process that can convert plastic to jet fuel or other high-demand products in just an hour.

A man walks on a mountain of plastic bottles as he carries a sack of them to be sold for recycling in Nairobi, Kenya, in 2018. (AP Photo/Ben Curtis, File)

(CN) — Researchers at Washington State University say they have developed a way to convert plastic into jet fuel and other valuable products in less than an hour, making plastics recycling easier and more cost effective. 

In their work, the scientists were able to convert 90% plastics to valuable hydrocarbon products within an hour and could easily alter the process to create the products they want.

The research was led by graduate student Chuhua Jia and Hongfei Lin, associate professor at the WSU Voiland School of Chemical Engineering and Bioengineering. Their findings were published Monday in the journal Chem Catalysis.

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

The accumulation of plastic waste has created a global environmental crisis, with an estimated 11% of plastics worldwide ending up in the ocean every year in addition to spoiling other pristine habitats. By the end of the decade, an estimated 53 million tons of plastic could end up in rivers, lakes and oceans annually, according to an unrelated study published last year in Science Focus.

Plastics recycling, however, has presented numerous problems. The most common mechanical recycling method melts plastic and then remolds it, but the result is a lower quality product that doesn’t easily sell for reuse. Chemical recycling can produce higher quality products, but the process requires high reaction temperatures and a long processing time, making it too expensive and difficult for industries to adopt. As a result, only about 9% of plastics are recycled annually.

In their work, the WSU researchers developed a catalytic process that quickly and efficiently converted polyethylene, the most common type of plastic in the world, into jet fuel. Polyethylene is in used in many everyday products, including plastic bags, milk jugs, shampoo bottles, wood composite, corrosion-resistant piping and plastic furniture.

Using a ruthenium on carbon catalyst and a commonly used solvent, researchers were able to convert about 90% of the plastic they attempted to recycle to jet fuel components and other hydrocarbon products within an hour at a temperature of roughly that used to bake salmon or a pizza – 428 degrees Fahrenheit, which is lower than other similar processes.

Jia was surprised by how well the solvent and catalyst worked.

“Before the experiment, we only speculated but didn’t know if it would work,” he said. “The result was so good.”

Adjustments to the temperature, time or amount of catalyst used allowed for the crucial step of being able to fine tune the process to allow for desirable products, Lin said.

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

The process is likely to work effectively with other types of plastic as well, according to the study.

The researchers are working with support from the Washington Research Foundation to scale up the process for future commercialization. They are working in collaboration with researchers from the Pacific Northwest National Laboratory, including professor Jim Pfaendtner. The work was funded by the Washington State Research Foundation and the National Science Foundation.

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