Catalysis for production of jet fuel from renewable sources by hydrodeoxygenation and hydrocracking

The increase in demand for green fuel sources has led to the development of biomass conversion and upgrading processes. High oxygen content deems bio-oil unsuitable for energy generation due to its corrosiveness and low heating value, hence bio-oil needs upgrading. Hydrodeoxygenation (HDO) and hydrocracking (HDC) are catalytic hydrotreating processes suitable for the production of renewable jet fuel, which is mainly composed of aliphatic and aromatic hydrocarbons (C₈–C₁₆). This chapter addresses current advances in HDO of model compounds as well as real feeds over a variety of noble and transition metal catalysts. The effects of bifunctional, bimetallic and sulfided catalysts on activity and selectivity are discussed, together with the effect of support type on the reaction. High deoxygenation degree was successfully demonstrated in HDO of fast pyrolysis oil over noble metal catalysts. HDC activity of various vegetable oils is also presented, showing promising results for obtaining hydrocarbons. The industrial application of HDO and HDC of real feedstocks is still rather limited due to fast catalyst deactivation and the complexity of the feedstock itself. Future research will address the challenges of catalyst stability and lowering reaction conditions through new technologies identified based on existing literature, such as electrocatalysis and plasma utilization.