Catalytic Upgrading Biocrude from Grindelia Squarrosa to Jet Fuels through Aqueous Phase Hydrodeoxygenation

Catalytic upgrading biocrude from grindelia squarrosa to jet fuels through aqueous phase hydrodeoxygenation

Xiaokun Yang¹, Glenn Miller², Simon Poulson³, Steve Spain⁴, and Hongfei Lin^1*

¹Chemical Engineering and Materials Science Department, ²Agriculture, Biotechnology & Natural Resources Department, ³Geological Sciences & Engineering Department, ⁴Chemistry Department, University of Nevada, Reno, NV, U.S 89557

E-Mail: hongfeil@unr.edu;

Biomass feedstocks that grow on arid/semiarid lands are good solutions that do not conflict with food and feed production. To utilize marginal arid land, which is unsuitable for food crop cultivation, the dedicated energy crop can be truly valuable. Grindelia squarrosa, also named as gumweed, is an arid land plant. The production rate of the biocrude oil extracted from gumweed is about 70-85 gal/acre on an annualized basis which is comparable to that of soy beans, except that gumweed needs much less water and fertilizers. The main component in gumweed biocrude is grindelic acid, a tricyclic diterpenoid, instead of triglycerides or fatty acids in the biocrudes of other oilseed plants. Herein, bi-functional solid acid supported noble metal catalysts was used to catalyze the conversion of the gumweed biocrude to bio jet fuels by hydrodeoxygenation in hydrothermal media. Compared to pyrolysis processes with the main products as aromatics which are not high-quality jet fuels, the aqueous phase hydrodeoxygenation produced many branched alkanes and cyclic alkanes that are excellent jet fuel components. Different solid acid supports had profound effect on the yield of bio jet fuels. The effects of reaction conditions such as reaction temperature and catalyst loading were also investigated.  At the optimum condition, the yield of ~72% bio jet fuel components was obtained from gumweed biocrude extract with the 1% Pd/W-ZrO₂ catalyst.