Scientists have successfully tested a new method for creating sustainable jet fuel using agricultural waste that is rich in lignin. This research, which has been published in the journal Fuel Processing Technology, shows a continuous process capable of converting lignin polymers—important components of plant cells—into a type of jet fuel that may enhance the performance of eco-friendly aviation fuels.
Researchers at Washington State University have made strides in developing sustainable jet fuel from lignin-based agricultural waste.
The study highlighted a method called “simultaneous depolymerization and hydrodeoxygenation,” which effectively breaks down lignin while removing oxygen, yielding lignin-based jet fuel. At their facility in Richland, the scientists mixed dissolved lignin polymer into a continuous hydrotreating reactor to create the fuel.
“Our work moves this technology closer to practical application by providing valuable data that helps evaluate its viability for commercial aviation,” stated Bin Yang, the lead researcher and a professor in WSU’s Department of Biological Systems Engineering.
Lignin, a structural molecule that contributes to the toughness of plants, is obtained from corn stover—stalks, cobs, and leaves left after harvesting—and other agricultural residues.
In 2019, global aviation fuel consumption hit nearly 100 billion gallons, with expectations for increased demand in the future. Sustainable aviation fuels that come from plant-based materials might help lower the carbon footprint of air travel, reduce contrails, and support international carbon neutrality initiatives.
The use of lignin-based fuel could lead to cleaner, more efficient sustainable fuels suitable for jet engines. Due to their density and properties that help with seal-swelling, hydrocarbons derived from lignin could serve as effective replacements for fossil fuel-derived compounds known as aromatics, which, although associated with contrails and climate issues, are still used due to their beneficial effects on fuel density and seal performance in engines.
This research represents the team’s initial successful trial of a continuous process, which is more practical for commercial scaling. Notably, the project utilized a less refined, more affordable type of lignin from corn stover, termed “technical lignin,” instead of using extracted lignin bio-oil seen in previous studies.
The results indicate that lignin could be a valuable source of cycloalkanes and other important fuel compounds that can replace aromatics.
“The aviation industry aims to produce 100% renewable aviation fuel,” remarked Josh Heyne, a member of the research team and co-director of the WSU-PNNL Bioproducts Institute. “Lignin-based jet fuel can enhance existing technologies by increasing the density of fuel blends, for example.”
With lower emissions, fuels made from lignin have the potential to be fully “drop-in” compatible, meaning they can be used interchangeably with current engines, infrastructure, and aircraft just like traditional fossil-derived aviation fuel.
“We are focused on developing a practical, commercially viable technology for a blend component that meets the 100% drop-in requirement,” Heyne explained.
This research received support from the U.S. Department of Energy’s Bioenergy Technologies Office, the Pacific Northwest National Laboratory, the National Renewable Energy Laboratory, and Advanced Refining Technologies LLC.
The team is now aimed at optimizing their process to achieve greater efficiency and reduce costs.
