(420e) Catalytic Deoxygenation of Butyric Acid Derived From Biomass for Production of Jet Fuel

Butyric acid can be produced by fermentation of biomass using Clostridium butyricum as biocatalyst and it is also produced as a by-product with acetone-n-butanol-ethanol (ABE) mixture in the well known 'ABE fermentation process'. Applying advanced fermentation method with integrated separation processes, a product concentration of 20 gl^-1 was achieved and it can be further increased by using synthetic microbial strain which can overcome the product inhibition effect experienced in bio-butanol production. Butyric acid derived from biomass can be converted to drop-in hydrocarbon fuel by catalytic deoxygenation process using commercial acid catalysts as γ-Al₂O₃ and ZSM-5, Zeolite.  At operating conditions of 400°C and 3 bars, conversion of pure butyric acid in a packed bed tubular reactor on γ-Al₂O₃ catalyst produces an organic liquid product phase immiscible with water at a very high yield of 80.5 wt%. The higher heating value (HHV) of the liquid organic product is 23.5 kJ/g. The organic liquid produced contains mostly saturated and unsaturated ketones which can be again deoxygenated to produce higher hydrocarbon molecules. With increasing temperature and decreasing weight hourly space velocity (WHSV) of the process, product composition and components can be altered and heavier hydrocarbon molecules can be produced in a single step. A two- step catalytic deoxygenation approach with series packed bed reactors having γ-Al₂O₃ and ZSM-5, Zeolite as catalysts respectively is compared with a one step catalytic deoxygenation process in terms of energy content of the final products and also total energy consumption of the entire process.