Theses and Dissertations


Gang Huang

Issuing Body

Mississippi State University


Toghiani, Rebecca K.

Committee Member

Toghiani, Hossein

Committee Member

Bricka, R. Mark

Committee Member

Pittman, Charles U., Jr.

Date of Degree


Document Type

Dissertation - Open Access


Chemical Engineering

Degree Name

Doctor of Philosophy


James Worth Bagley College of Engineering


Dave C. Swalm School of Chemical Engineering


Eight alcohols in their supercritical states were used individually to treat crude bio-oil and pine wood chips. All supercritical alcohols studied, with the exception of tertbutanol, exhibited the ability to decrease the oxygen content, acid value and/or remove unstable compounds from the crude bio-oil. For supercritical 1-butanol, its use for upgrading of crude bio-oil resulted in a product with much lower oxygen content, lower acid value and fewer unstable compounds. Two CoMo catalysts were examined for their impact on the bio-oil upgrading process with supercritical alcohol. Their influence on the oxygen content, acid value and concentrations of unstable compounds in the processed bio-oil was examined. The basic CoMo/MgO catalyst was demonstrated to effectively eliminate acid content from the bio-oil, regardless of the alcohol employed. Compared with crude bio-oil produced by fast pyrolysis of pine wood lumber, the liquid products produced from supercritical alcohol treatment of pine wood chips possessed one or more of the desirable characteristics: lower acid value, lower oxygen content and fewer unstable compounds. Generally, supercritical butanol isomers produced liquid fuels with lower oxygen content. However, the bulky structure of branched alcohol isomers (secondary and tertiary alcohols) appeared to hinder the degradation of pine wood chips. The CoMo/MgO catalyst exhibited the ability to decrease the acid value, but not to decrease the oxygen content in the liquid product. Wood chip size, wood chip/methanol mass ratios, temperatures, pressures and reaction time were examined in this work. However, the influence of these variables on liquid yield from supercritical methanol treatment of pine wood chips was not substantial.