A catalytic process developed by Washington State University (WSU) researchers reportedly can efficiently convert waste polyethylene-based products into jet fuel and high-value lubricants. The technology is able to convert 90% of the plastic within an hour at moderate temperatures, and it can be fine-tuned to create specific products. Results of the study, led by graduate student Chuhua Jia and Hongfei Lin, associate professor in the Gene and Linda Voiland School of Chemical Engineering and Bioengineering, were published in the Chem Catalysis journal.
“In the recycling industry, the cost of recycling is key. This work is a milestone for us to advance this new technology to commercialization,” Lin told Tina Hilding, writing in the WSU Insider.
The most common mechanical recycling methods melt the plastic and re-mold it, but that lowers its economic value and quality for use in other products. Chemical recycling can produce higher quality products, but it has required high reaction temperatures and a long processing time, making it too expensive and cumbersome for industries to adopt. Because of its limitations, only about 9% of plastic in the US is recycled every year, writes Hilding.
The WSU researchers developed a catalytic process to efficiently convert polyethylene to jet fuel and high-value lubricants. By using a ruthenium on carbon catalyst and a commonly used solvent, they were able to convert about 90% of the plastic to jet fuel components or other hydrocarbon products within an hour at a temperature of 220°C (428°F), which is more efficient and lower than temperatures that would be typically used.
Jia was surprised to see just how well the solvent and catalyst worked, writes Hilding.
“Before the experiment, we only speculated but didn’t know if it would work,” he said. “The result was so good.”
Adjusting processing conditions, such as the temperature, time, or amount of catalyst used, provided the critically important step of being able to fine-tune the process to create desirable products, Lin told Hilding.
“Depending on the market, they can 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.”
With support from the Washington Research Foundation, the researchers are working to scale up the process for future commercialization. They also believe their process could work effectively with other types of plastics.
The work was done in collaboration with researchers from the University of Washington and Pacific Northwest National Laboratory, including Professor Jim Pfaendtner. It was funded by the Washington State Research Foundation and the National Science Foundation.