Fast pyrolysis is a promising biomass conversion technology to convert solid biomass to liquid bio-oil that has a potential to be upgraded into chemicals or fuels. However, high acidity and reactivity of a raw bio-oil creates utilization problems such as instability and corrosivity during storage, making the oil less attractive as renewable sources. Thus, knowledge of how to manipulate bio-oil composition by reducing acidity or reactivity during pyrolysis is important in commercializing pyrolysis process. Research in this dissertation focuses on a manipulation of the bio-oil species with different approaches.

While significant effort has been spent to understand the pyrolysis chemistry of cellulose with key success, a complex structure of lignin has been a bottleneck in understanding lignin pyrolysis. Thus, pyrolysis reaction pathways of lignin model compounds have been investigated in attempt to understand native lignin pyrolysis. This study suggests that not only free radical reaction which has been predominantly proposed in literatures but also pericyclic reaction is significantly involved in pyrolysis.

Secondly, catalytic manipulation of bio-oil composition was quantitatively studied by performing a full mass balance on all of the products generated from in situ CFP. This study demonstrates that the high consumptions of C and H of bio-oil during CFP led to lower energy recovery with CFP than thermal pyrolysis.

Due to the low energy recovery from in situ CFP, a third study aimed to study a vapor manipulation using ex situ adsorbent. CaCO3, adsorbent, showed a high activity for acetic acid removal by forming calcium acetate. It was also found that selectivity toward acid removal was improved by a partial regeneration of the material to lead to a presence of the relatively inert acetate group on surface.