EX-SITU HYDROGEN BIOMETHANATION: REVIEW OF TECHNOLOGIES AND DEVELOPMENT PROSPECTS WITHIN THE BIOMETHAVERSE PROJECT

Abstract

Purpose. The study aims to analyse contemporary ex-situ hydrogen biomethanation technologies demonstrated in the BIOMETHAVERSE project and to assess their technological potential, limitations, and applicability for future large-scale deployment.

Objectives. The research focuses on:

comparing three technological pathways – biological methanation using membrane biofilm and suspended biomass systems (EBM), catalytic methanation based on Ni- and Ru-supported catalysts (ETM), and biological methanation of syngas in trickle-bed reactors (ESB);

identifying key process bottlenecks related to mass transfer, microbial stability, catalyst durability, energy consumption, and scale-up;

evaluating the prospects of integrating these technologies into existing biogas infrastructures.

Methods. The study employs a comparative technological analysis based on data from BIOMETHAVERSE demonstration sites in Italy, Greece, and Sweden, supplemented by recent peer-reviewed studies. Assessed parameters include gas composition, CH₄ yield, operational stability, mass- and heat-transfer characteristics, and catalyst behaviour. Life-cycle and techno-economic considerations described in project deliverables were additionally taken into account.

Results. EBM demonstrated an increase in biomethane production of ~78% and stable CO₂-to-CH₄ conversion using membrane biofilm reactors, despite limitations related to hydrogen mass transfer and microbial balance. ETM produced biomethane with 96–98% CH₄ purity, though catalyst degradation, thermal management, and hydrogen demand remained significant constraints. ESB showed effective biological utilisation of syngas and integration potential with gasification systems, yet was sensitive to CO inhibition and mass-transfer limitations.

Overall, the three approaches represent complementary routes within the Power-to-Methane concept and are suitable for different feedstocks and infrastructural conditions. Their combined development provides a promising pathway for expanding renewable methane production, including potential application within the Ukrainian bioenergy sector.