Xiaobo Zhou

Date of Award


Level of Access Assigned by Author

Campus-Only Thesis

Degree Name

Master of Science (MS)




Brian G. Frederick

Second Committee Member

M. Clayton Wheeler

Third Committee Member

Barbara Cole


Fossil fuels have been major energy sources for decades. Although easily accessible petroleum is limited, continued use of fossil fuels is causing serious environmental issues, one of which is the greenhouse effect, providing incentives for development of alternative energy sources. Biomass is one of the most important sources of renewable liquid fuels. One process for conversion of biomass is fast pyrolysis. However, the biooil produced by the fast pyrolysis process has several disadvantages, such as high oxygen and water content, high viscosity and low pH, which decrease its quality as a transportation fuel. Hydrodeoxygenation (HDO) processes are needed to upgrade and improve the quality of pyrolysis oil. This thesis will review progress in the development of hydrodesulfurization, precious metal, and reducible metal oxide catalysts for HDO. Development of catalysts that are effective as well as robust is critical to the ultimate commercial success of the pyrolysis route.

In this thesis, a detailed study of the stabilization effect was done by using different reaction conditions and the product chemical composition was analyzed using NMR and GCMS techniques. The whole pyrolysis oil HDO reaction was done using a 2-step procedure; a mild reaction condition was used during the 1st step of the reaction to stabilize the pyrolysis oil, before increasing the temperature and hydrogen pressure for the 2nd HDO step. The product oil from each step was analyzed using NMR and GCMS to determine the compounds being produced and removed during the reaction. The second part of the research in this thesis focused on the effect of water on the product oil quality of the HDO reaction. The H2 consumption during the reaction was calculated based on a self-designed calibration system and an accurate mass balance calculation was done for each phase of the product oil. The results showed a dramatic decrease of the product oil yield when more than 50% of water was added to the reaction, which could possibly be caused by the aqueous reforming of the OH-containing compounds.