Catalytic deoxygenation of waste soybean oil over hybrid catalyst for production of bio-jet fuel: in situ supply of hydrogen by aqueous-phase reforming (APR) of glycerol

Production of Jet Biofuels by Catalytic Hydroprocessing of Esters and Fatty Acids: A Review

The transition from fossil to bio-based fuels is a requisite for reducing CO2 emissions in the aviation sector. Jet biofuels are alternative aviation fuels with similar chemical composition and performance of fossil jet fuels. In this context, the Hydroprocessing of Esters and Fatty Acids (HEFA) presents the most consolidated pathway for producing jet biofuels. The process for converting esters and/or fatty acids into hydrocarbons may involve hydrodeoxygenation, hydrocracking and hydroisomerization, depending on the chemical composition of the selected feedstock and the desired fuel properties. Furthermore, the HEFA process is usually performed under high H2 pressures and temperatures, with reactions mediated by a heterogeneous catalyst. In this framework, supported noble metals have been preferably employed in the HEFA process; however, some efforts were reported to utilize non-noble metals, achieving a similar performance of noble metals. Besides the metallic site, the acidic site of the catalyst is crucial for product selectivity. Bifunctional catalysts have been employed for the complete process of jet biofuel production with standardized properties, with a special remark for using zeolites as support. The proper design of heterogeneous catalysts may also reduce the consumption of hydrogen. Finally, the potential of enzymes as catalysts for intermediate products of the HEFA pathway is highlighted.

Catalytic Deoxygenation of the Oil and Biodiesel of Licuri (Syagrus coronata) To Obtain n-Alkanes with Chains in the Range of Biojet Fuels

Aviation industry has the challenge of halving CO₂ emissions by 2050, as compared to 2005. An alternative are drop-in biofuels, which are sustainable and fully compatible with aircraft engines and also can be mixed with fossil jet fuel. Among the feedstock for biojet fuel production, licuri (Syagrus coronata) can be highlighted as most of its fatty acids are in the jet fuel range. Thereby, this work investigated the composition and physicochemical characterization of licuri oil and licuri biodiesel, both with satisfactory results according to international standards, with the purpose of obtaining hydrocarbons in the range of jet fuel from these feedstock, by catalytic deoxygenation. The semi-batch reaction, using a 5% Pd/C catalyst at 300 °C and 207 psi, produced n-alkanes with a conversion of up to 39.2%. The n-alkane selectivity was 80.7%, in addition to CO₂ selectivity of 83.4% for biodiesel, indicating the preference for the decarboxylation pathway and also confirming licuri as a potential raw material for biojet fuel.