Pyrolysis of Alkali Pre-Treated Biomass and Biomass Constituents

Although upgrading of pyrolysis oil has been extensively studied, it is still plagued with low product yields and significant catalyst deactivation.   These issues are largely because of the instability of oxygenated species in pyrolysis oil, which leads to considerable char formation by polymerization at the elevated temperatures that are required for hydrodeoxygenation.  In the current study, we eliminate compounds that cause polymerization by pre-treating sawdust with various alkali compounds before pyrolyzing it in a fluidized bed reactor. The resulting stabilized oils have significantly lower oxygen content than conventional pyrolysis oil.  The higher heating values of the oils are in the range of 40 MJ/kg, and the energy yields exceed those commonly achieved in catalytic fast pyrolysis.  Detailed analysis of conventional and pre-treated pyrolysis oils is presented and potential reaction mechanisms are discussed.