Catalytic processes for upgrading of bio-oils will be a key part of biorefineries because they provide the much needed links between the production of bio-oils by pyrolysis or liquefaction and the synthesis of renewable chemicals and biofuels that can be blended into the existing gasoline pool. Hydrodeoxygenation (HDO) is an attractive process to achieve this goal by replacing oxygen containing functional groups with hydrogen, while water is formed as the only by-product. The process provides oils with reduced reactivity and corrosiveness and increases the energy density of the oil. Nobel metal containing zeolite catalyst show considerable HDO activity, but deactivation by coking remains an issue. Further insight into the surface reaction paths for HDO and coke formation is needed optimize the composition of these catalysts as well as the conditions for the HDO process and regeneration procedures.
In this work, we use time-resolved operando IR spectroscopy to elucidate the reaction paths of aromatic oxygenates during HDO over H-BEA and Pt/H-BEA zeolites. Trends in reactivity and selectivity are explained based on nature of surface species formed from different oxygenates. It is also shown that carbonaceous deposits can undergo several stages of aging before significant deactivation is observed. Insight into these transformations will allow for developing protocols for efficient regeneration of spent HDO catalysts.
See more of this Group/Topical: Catalysis and Reaction Engineering Division