CIRCULAIR: Sustainable Jet Fuels from Manure and Straw

The CIRCULAIR project addresses these challenges by developing an advanced biomass conversion pathway for cost-effective fuel production from abundant agricultural residues through hydrothermal liquefaction (HTL). CIRCULAIR’s key innovations cover the entire process chain from feedstock to final fuels and by-products. 

Manures and straw were chosen as feedstocks, due to their abundance in agriculture and potential synergy effects in the co-liquefaction of these feedstocks. CIRCULAIR investigates the co-liquefaction phenomenon and aims at solving the process water challenge of HTL by closely integrating HTL conversion with wet oxidation of HTL process waters. Biomass resource utilisation will be maximised by developing suitable valorisation schemes for all relevant side streams. In particular, volatile fatty acids will be extracted from HTL process waters and methanol will be synthesised using CO₂ from effluent gas streams and renewable hydrogen. CIRCULAIR will fill a knowledge gap regarding the use of HTL chars for soil application, thereby creating a negative contribution to the carbon footprint.

In addition, CIRCULAIR will develop innovative approaches to upgrade HTL biocrudes to on-specification jet fuel and thereby prepare the approval process of HTL jet fuel for civil aviation. RISE takes part in this work package by investigating the upgrading of HTL biocrude using slurry hydro-treatment process.