Wood By-Product Used to Create Jet Fuel

Researchers at Washington State University (WSU) Tri-Cities have discovered a method to convert a common wood by-product into hydrocarbon molecules that could be used as jet fuel.

A procedure developed and patented by Bin Yang, associate professor of biological systems engineering, uses a catalytic process to convert lignin, an organic polymer that makes plants woody and rigid, into a mix of hydrocarbons in a single reactor. The product can be separated and purified to obtain hydrocarbons that are usable in turbine engines.

Lignin is one of the most abundant renewable carbon sources, with 40-50 million tons produced annually worldwide. However, it is generally treated as a waste by-product of the conversion of plant biomass into biofuels such as ethanol.

According to Ralph Cavalieri, director of WSU’s Office of Alternative Energy, molecules derived from biomass currently must be combined with petroleum-based jet fuel to meet certification requirements. Yang’s procedure, however, may be able to supply molecules that can be certified for jet engines without the addition of petroleum-based jet fuel.

Typically, jet fuel requires molecules that consist of 12-16 carbon atoms to fulfill jet engine requirements, Cavalieri says. By comparison, gasoline, a more volatile fuel, requires molecules with fewer carbon atoms. Diesel, an even less volatile fuel than gasoline, requires molecules of 16-20 or more carbon atoms. However, it begins to gel at cold temperatures.

Cavalieri says that jet fuel requires the same nominal range of molecules as kerosene, which isn’t as volatile as gasoline but also doesn’t freeze at the cold temperatures found at high altitude.

“With the research being conducted by Dr. Yang, it may be possible to develop a more complete suite of molecules required for turbine engine systems using only biomass feedstocks, making the process more economically feasible and efficient,” he says.

Yang’s team is working with Boeing Co. to develop and test the hydrocarbons targeted for use as jet fuel.