Illinois Sustainable Technology Center scientists at the Prairie Research Institute have found that waste plastic can be used to improve sustainable aviation fuel.

Hong Lu, a research scientist at ISTC, said the project for UHV Technologies was funded by the U.S. Department of Energy. Lu and ISTC colleagues, research scientists Nandakishore Rajagopalan and Jaemin Kim, completed a report on the research this summer.

“Planes will continue to burn fuel,” Lu said. “To reduce carbon emissions associated with aviation fuel, sustainable aviation fuel is the only option. Landfill-bound waste plastic can be a source for sustainable aviation fuel.”

For the study, non-foam types of polystyrene — a category of plastics — was depolymerized to produce an aromatics-rich crude oil and then blended with synthetic paraffinic kerosene, also called SPK. The resulting fuel had improved aviation fuel properties including a higher density, lower viscosity, lower freezing point, and improved O-ring seal swelling.

The findings have the potential to remove a major hurdle for sustainable aviation fuel — some synthetic paraffinic kerosene does not meet the specifications for aviation fuel — and increase the availability of sustainable aviation fuel as an alternative.

The U.S. Department of Energy and other federal government agencies have outlined a Sustainable Aviation Fuel Grand Challenge, with goals including to domestically supply three billion gallons of sustainable aviation fuel per year by 2030 and 100% of projected annual domestic commercial jet fuel use by 2050.

Lu noted that the researchers’ next question is how to scale up production and reduce cost. They are seeking funding for a second phase to answer that question, which is expected to be a two-year project.

Regarding the waste plastic, Lu said advanced sorting technologies can be used to manage the risks of food contamination and certain plastics additives. Initial modeling shows it can be economically feasible to source the waste plastic for aviation fuel and substantial amounts of it are available because less than 10% of annual production is recycled.

“The more plastic is recycled instead of landfilled, the lower the cost of the sustainable aviation fuel from waste plastics will be,” Lu said. “Everyone can contribute to carbon reduction by simply throwing a piece of plastic into a recycling bin instead of a landfill one.”