Exploring the synergies between direct carbon-capture, nutrient recovery and next-generation purification technologies for cost-competitive and sustainable microalgal aviation fuel

Microalgae can play a critical role in meeting EU targetsto increase the share of Sustainable Aviation Fuels(SAFs) in the aviation industry from 2% in 2025 to 64% by 2050. SusAlgaeFuel will develop integrated approaches in a circular production model towards the first cost-competitive (reduced by 49% from 12.3 to 6.3 $/kg HEFA) and efficient microalgae SAF: a) direct capture of CO2 emissions from biogas upgrading from Anaerobic Digestion (AD) and utilisation of waste liquid digestate as low-cost nutrient source to support algae growth; b) novel in-line process analytical technology complemented with machine learning and selective UV irradiation to monitor and purify bacterial contamination in algae culture; c) cascading biorefinery that relies on energy-saving autolysis and maximises solvent recycling to fractionate biomass into lipids (for jet fuel), protein serum (for feed) and cellulose-rich biomass residue (for further fuel conversion) at low energy & solvent requirements; d) algae-specific thermocatalytic pathways for efficient conversion of algae-lipids to Hydroprocessed Esters Fatty Acids-Synthetic Paraffinic Kerosene (HEFA-SPK) and residue to kerosene followed by a range of purification methods for fuel refinement to meet international aviation standards & certification. Process simulations, techno economic & LCA will be performed to assess scalability from economic, social & environmental perspectives and to identify process improvements. A dedicated commercialisation plan and policy recommendations will be produced to guide future technology transfer from lab to industry. SusAlgaeFuel will culminate in the building & operation of a pilot-scale algal facility on an AD operator site in Ireland (TRL5) with the capacity to directly capture CO2 from AD flue gas, use waste digestate and produce =10 kg of algae lipids per year. Successful future scaling of the technology has the potential to deliver 20% of EU’s projected SAF requirements of...