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Hydropyrolysis of Lignin using Pd/HZSM-5 Oliver D. Jan Chair of the Supervisory Committee:Dr. Fernando Resende School of Environmental and Forest SciencesThe aim of this work was to study the formation of cycloalkanes from hydropyrolysis of lignin with HZSM-5 and Pd/HZSM-5 catalysts. We observed that palladium supported on HZSM-5 catalyzed hydrogenation and deoxygenation reactions that converted phenolic compounds into aromatic hydrocarbons and cycloalkanes. This study analyzed the effect of the catalyst-to-lignin ratio, H 2 partial pressure, and temperature on the yields of hydrocarbons with HZSM-5 and Pd/HZSM-5. Pd/HZSM-5 produced 44% more aromatic hydrocarbons than HZSM-5 at a catalyst-to-lignin ratio of 20:1, 650ºC, and a constant H 2 partial pressure of 1.7 MPa. The presence of palladium led to significant difference in yields only at 1.7 MPa H 2 partial pressure.In both the in-situ and ex-situ experiments conducted, hydropyrolysis temperature played a substantial role in the equilibrium conversion of hydrogenation reactions that led to cycloalkanes directly from lignin.iv Dedication This thesis is dedicated to my family for all their love and support v Acknowledgements

This article reports the first results for gasification of lignin in supercritical water in the complete absence of metal catalysis, by using quartz reactors. It also reports the first systematic study of the effects of temperature, lignin loading, water density, and reaction time on the production of H 2 , CH 4 , CO, and CO 2 from lignin in supercritical water. CH 4 and CO 2 are always the major products. CO is formed, and its yield decreases with time. The yield of H 2 generally increases with time. With other variables fixed, the yields of H 2 , CH 4 , and CO 2 increase with temperature but exhibit minima as lignin loading and water density increase. The CO yield decreases with increasing lignin loading, water density, and temperature. Manipulating lignin loading provides an efficient means to control the CH 4 /H 2 molar ratio. The highest H 2 yield was 7.1 mmol/g, obtained at 725°C and 60 min. Supercritical water gasification at 5.0 wt % lignin loading and 600°C provided the highest total gas yield (90 wt %).

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