Reviewed by Lexie CornerSep 27 2024
Scientists at Washington State University have successfully tested a new method to convert lignin-based agricultural waste into sustainable jet fuel. The study was published in the journal Fuel Processing Technology.
Joshua Heyne, Director of the WSU Bioproducts, Sciences, and Engineering Laboratory, and Research Assistant Conor Faulhaber examine swelling results from a material compatibility test related to sustainable fuels. Image Credit: Washington State University.
Lignin, a structural component found in agricultural byproducts like corn stover (stalks, cobs, and leaves left after harvest), gives plants their woody texture. The team developed a process called "simultaneous depolymerization and hydrodeoxygenation," which dissolves lignin and removes oxygen simultaneously to produce lignin-based jet fuel. The researchers fed dissolved lignin polymer into a continuous hydrotreating reactor at their Richland facility to create the fuel.
Our achievement takes this technology one step closer to real-world use by providing data that lets us better gauge its feasibility for commercial aviation.
Bin Yang, Study Lead Scientist and Professor, Department of Biological Systems Engineering, Washington State University
Global aviation fuel consumption reached nearly 100 billion gallons in 2019, with demand expected to rise in the coming decades. Sustainable aviation fuels derived from plant-based biomass could reduce aviation’s carbon footprint, lower contrail formation, and help achieve global carbon neutrality goals. Lignin-based jet fuel could make sustainable fuels cleaner and more compatible with jet engines by replacing fossil fuel-derived aromatic compounds. Although aromatics improve fuel density and seal-swelling properties in metal joints, they are linked to contrail formation and climate impacts.
The team successfully tested a continuous production process for the first time, making commercial-scale production more feasible. This project used "technical lignin," a less processed and less expensive form of lignin from corn stover, instead of the extracted lignin bio-oil used in previous studies. Their findings suggest that lignin could be a valuable source of cycloalkanes to replace aromatics and enhance fuel properties.
The aviation enterprise is looking to generate 100 % renewable aviation fuel. Lignin-based jet fuel complements existing technologies by, for example, increasing the density of fuel blends.
Josh Heyne, Research Team Member and Co-Director, Bioproducts Institute, Washington State University
Lignin-based fuel could significantly lower emissions and eventually make sustainable aviation fuels fully "drop-in" compatible, meaning they could be used seamlessly with existing aircraft, infrastructure, and engines, just like conventional fossil fuel-derived aviation fuel.
We’re working to create an effective, commercially relevant technology for a complementary blend component that can achieve the 100% drop-in goal.
Josh Heyne, Research Team Member and Co-Director, Bioproducts Institute, Washington State University
The study was funded by the US Department of Energy's Bioenergy Technologies Office, the National Renewable Energy Laboratory, the Pacific Northwest National Laboratory, and Advanced Refining Technologies LLC.
The team is now focused on optimizing the process to increase efficiency and reduce costs.
Journal Reference:
Kumar, A., et al. (2024) A simultaneous depolymerization and hydrodeoxygenation process to produce lignin-based jet fuel in a continuous flow reactor. Fuel Processing Technology. doi.org/10.1016/j.fuproc.2024.108129