MIT's breakthrough in crafting 100% sustainable aviation fuel
Professor Yuriy Román-Leshkov and collaborators have demonstrated a new way to produce a critical component of aviation fuel from lignin, a plant material that’s generally discarded as waste during biomass processing. Photo courtesy of Gretchen Ertl / MIT

MIT’s breakthrough in crafting 100% sustainable aviation fuel

Consumption of jet fuel is projected to double between now and 2050. However, creating a fully sustainable hydrocarbon fuel for aircraft has been elusive, primarily due to the stringent regulations surrounding aviation fuels. Meanwhile, the aviation industry has committed to achieving carbon neutrality by 2050, when the demand for jet fuel is expected to double.

Yuriy Román-Leshkov, the Robert T. Haslam Professor of Chemical Engineering at the Massachusetts Institute of Technology (MIT) in Cambridge, Massachusetts, U.S.A., explains the intricacies of aviation fuel composition and the challenges of ensuring its safety and reliability at high altitudes.

A significant portion of aviation fuel consists of “aliphatic” molecules, resembling diesel fuels. The rest comprises “aromatic” molecules, which are essential for maintaining the physical and combustion properties of the fuel and ensuring the integrity of the aircraft’s fuel system seals.

While the aliphatic component can be derived sustainably from plant-based sources, producing the aromatic fraction sustainably has been a challenge. This limitation has resulted in a “blending wall,” restricting the amount of sustainable aliphatic hydrocarbons that can be incorporated without altering the fuel’s properties.

Román-Leshkov and his team at MIT, in collaboration with other institutions, have been focusing on lignin, a robust plant material. Despite its abundance, converting lignin into valuable products, including the aromatic molecules essential for jet fuel, has been challenging.

The team’s innovative approach involves using a ruthenium-based catalyst to extract lignin, producing a stable lignin oil. This oil is then processed using a molybdenum carbide catalyst, which efficiently breaks down the lignin into the desired aromatic molecules. Their method has achieved impressive carbon yields, exciting the catalysis community.

Initial tests on the resulting product have been promising, with properties closely aligning or even surpassing conventional aviation aromatics. The team is now scaling up their methods and exploring other biomass sources, such as pine and switchgrass.

If successful, this breakthrough could pave the way for truly sustainable aviation fuel, eliminating the blending wall and making 100% renewable aircraft fuel a reality.

This research, featured in the Spring 2023 issue of Energy Futures, has received support from the U.S. Department of Energy and Italian multinational energy company Eni S.p.A. through the MIT Energy Initiative.