Intensification of hydrodeoxygenation of liquid derived from pyrolysis: Guaiacol as model compound

Applying direct bio-oil derived from lignocellulosic materials via thermochemical processes i.e. pyrolysis to internal combustion engines is challenging due to its high oxygen content (30-40%) and thermal and chemical instability. Despite numerous efforts, the hydrodeoxygenation processes have encountered a number of issues such as rapid catalyst deactivation, large amount of hydrogen required (600-1000 L hydrogen per kilogram of bio-oil), high pressure (up to 300 bar), high temperatures (250-450 degrees C) and long reaction time (3-4 h). In this study, cold plasma operated at atmospheric conditions was applied for hydrodeoxygenation of guaiacol, a model compound to understand the mechanism, effect of operating conditions and interactions between catalyst and cold plasma on oxygen removal. Approximately 82% of guaiacol was converted into catechol, phenol, benzene and toluene within 3-4 s without catalysts. Adding the catalyst of cobalt supported on silica dioxide in the plasma zone enhanced the production of phenol to 44% at H-2 requirement of 315 L.kg(-1) of guaiacol.