Circular Integration of Anaerobic Digestion, Biomethanation and Hydrothermal Gasification for Competitive and Secure Biomethane Value Chains

The project will develop and optimize a multi-pathway valorization strategy for organic waste feedstocks. The proposed system integrates the following processes:

·         Dark Fermentation (DF) to produce H2, CO2 and DF Effluent (DFE);

·         Biological methanation to produce biogas (CH4 and CO2) and digestate from DFE;

·         Hydrothermal gasification (HTG) of digestate producing a H₂-rich syngas and carbonaceous solids (hydrochar);

·         Circular integration, to develop and couple dark fermentation, biological methanation (two-stage anaerobic digestion-AD), and hydrothermal gasification in a circular system that internally recycles hydrogen-rich syngas and uses hydrochar to enhance anaerobic digestion stability and methane yield.

·         Multi-Fuel Valorization: To engineer and optimize two distinct downstream synthesis pathways:

o    Shipping Fuel Synthesis: To demonstrate the efficient conversion of mixed gaseous streams (H2, CO, CO2, CH4) into methanol via a trickle bed reactor (TBR) for hydrogenotrophic methanogenesis followed by methanotrophic conversion.

o    Aviation Fuel Synthesis: To develop a downstream multi-step purification and catalytic conversion train for DF effluent, to produce synthetic paraffinic kerosene (SPK) from VFAs.