A team of researchers from Washington State University (USA) has successfully tested a new method of producing sustainable aviation fuel using lignin-based agricultural waste.
The study described a continuous process that directly converts lignin polymers, one of the main components of plant cells, into a form that could improve performance.
The study is published in the journal .
A sustainable aviation fuel could be made from corn
“Our achievement brings this technology closer to real-world application, providing data that allows us to better assess its feasibility for commercial aviation,” said Bin Yang, a professor in WSU’s Department of Biological Systems Engineering and team leader of research.
Lignin is a class of structural molecules that give plants their hardness and rigidity. This is derived from agricultural residues such as stalks, leaves and leftovers after harvesting.
The team developed a process called “simultaneous depolymerization and hydrodeoxygenation,” which breaks down the lignin polymer while removing oxygen to create jet fuel. In their lab in Richland, the researchers fed dissolved lignin polymer into a continuous hydrogenation reactor to produce this fuel.
The demand for jet fuel is increasing
Global jet fuel consumption reached a record of nearly 378.5 billion liters in 2019, and demand is expected to grow over the coming decades. Sustainable aviation fuels made from plant biomass could help reduce aviation’s carbon footprint, reduce contrails and achieve international carbon neutrality goals.
Fuel made from lignin could make sustainable fuels cleaner and easier to use in aircraft engines. Because of their density, efficiency and packing swelling properties, lignin-catalyzed hydrocarbons could effectively replace fossil fuel-derived compounds called aromatics. These compounds, associated with streaking and climate impact, are still used because they increase fuel density and help seal metal joints, .
This study marks the first successful test of a continuous process, more feasible for commercial production. The project also used a less processed and cheaper form of lignin obtained from corn residues, called “technical lignin”, unlike previous research that used lignin bio-oil.
This sustainable aviation fuel can easily replace fossil fuels
The team’s results suggest that lignin is a promising source of cycloalkanes, compounds that can replace aromatics and have useful applications in fuels.
“The aviation industry aims to generate 100% renewable fuel. “Lignin-based jet fuel complements existing technologies, for example, by increasing the density of fuel blends,” said Josh Heyne, research team member and co-director of the WSU-PNNL Bioproducts Institute.
With low emissions, lignin-based fuel could make sustainable aviation fuels fully compatible with existing engines and infrastructure, just like aviation fuels.
“We are working to create an efficient and commercially relevant technology for a complementary blend component that achieves the goal of 100% compatibility,” added Heyne.
The team is currently working on refining the process to increase efficiency and reduce costs.
