Residues being collected from tribal forest land for aviation biofuel production (photo: NRA)
Thu 10 Dec 2015 – Researchers at Washington State University Tri-Cities (WSU) in the United States say they have found a way to convert lignin, a common wood by-product, into the same hydrocarbon molecules that are used as jet fuel. The procedure developed by Dr Bin Yang, an associate professor of biological systems engineering, and his team converts lignin into a mix of hydrocarbons in a single reactor using appropriate catalysts, and the resulting product is then separated and purified to obtain the required jet fuel hydrocarbons. After cellulose, lignin is the most abundant renewable carbon source on Earth, according to the International Lignin Institute. Yang’s team is now working with Boeing to develop and test the discovery. Elsewhere in the Pacific Northwest, Alaska Airlines is expected to conduct a demonstration flight in 2016 using 1,000 gallons of jet biofuel derived from forest scraps.
Molecules derived from biomass currently must be combined with petroleum-based jet fuel to meet certification requirements for commercial jet fuel use. Jet fuel typically needs molecules that consist of 12 to 16 carbon atoms to fulfil jet engine requirements, said Ralph Cavalieri, Director of WSU’s Office of Alternative Energy. Gasoline requires molecules with fewer carbon atoms but is much more volatile, while diesel, which requires molecules of 16 to 20 or more carbon atoms begins to gel at cold temperatures.
Cavalieri said jet fuel requires the same nominal range of molecules as kerosene, which is not as volatile as gasoline but also does not freeze at the cold temperatures found at 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 said.
Added Yang, who holds a patent on the process: “The effort to transform lignin into higher-value products for large developed markets is critically needed. If we can make jet fuel from the biomass-derived lignin, it addresses this challenge.”
Lignin is an organic polymer that makes plants woody and rigid and is usually wasted when plant biomass, including cellulose, is converted into biofuels like ethanol. The Switzerland-based International Lignin Institute estimates between 40 and 50 million tons of lignin are produced annually worldwide, mostly as a non-commercialised waste product.
In addition to hydrocarbons suitable for jet fuel, Yang is using lignin to produce a variety of other chemicals and materials. The research is supported by various US government departments, including the Defense Advanced Research Projects Agency (DARPA), and the Seattle-based Joint Center for Aerospace Technology Innovation.
The findings of Yang and his team are published in Green Chemistry, a journal of the Royal Society of Chemistry.
Meanwhile, the forest residues being turned into jet fuel for use in an Alaska Airlines demonstration flight next year are being provided by the Confederated Salish and Kootenai Tribes (CSKT) and the Muckleshoot Indian Tribe through the Northwest Advanced Renewables Alliance Tribal Partnership Program (NARA TPP). The initiative is supported by a grant from the US Department of Agriculture’s National Institute of Food and Agriculture (NIFA).
CSKT and Muckleshoot are among many groups of Native American forest landowners in the Pacific Northwest. The tribes have been involved in every step of the way in generating the 1,000 gallons of fuel for the flight, said NIFA, with TPP assessing the economic opportunities for the tribally-sourced biomass and developing educational opportunities for Native American students. NIFA invests in and advances agricultural research, education and extension, and seeks to make transformative discoveries that solve societal challenges, it added.
Additional reporting by Maegan Murray, WSU Tri-Cities
Dr Bin Yang, centre, with his WSU Tri-Cities research team:
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