Long-Term Ex-Situ Biological Methanation of Hydrogen and Carbon Dioxide Coupled to a Novel Gas Mass Transfer System Based on Controlled Hydrodynamic Cavitation

16 Pages Posted: 22 Mar 2023

See all articles by Antonio Giuliano

Antonio Giuliano

Italian National Agency for New Technologies Energy and Sustainable Economic Development

Abstract

The present work represents the first study focused on controlled hydrodynamic cavitation applied as gas transfer system to supply the methanogenic archaea with exogenous H2 and CO2. Starting from a generic mixed inoculum sampled from a thermophilic full-scale anaerobic digester, a bubble column bioreactor was coupled with a rotating hydrodynamic cavitator and fed with different H2/CO2 loading rates. Process efficiency and long-term effects on process stability and microbial population were evaluated. Gas sparging through the controlled hydrodynamic cavitation device showed a high capacity of H2 mass transfer, resulting in almost 100% efficiency in H2 utilization and recording a CH4 volumetric content more than 99% in the gas leaving the reactor, without any gas recirculation from the headspace. The experimental trials lasted about 160 days and the behavior of the bioreactor showed a substantial stability over the time. Metagenomic and FISH analyses were carried out at the end of the experimental trials, revealing a remarkable increase of hydrogenotrophic methanogens species, related to the selection-effect of H2 on community composition. The findings provide previously unidentified insights into long-term effect on process stability and microbial community diversity in the biological hydrogenotrophic methanation process coupled with a gas-liquid mass transfer system based on controlled hydrodynamic cavitation technology.

Keywords: Ex-situ biological methanation, controlled hydrodynamic cavitation, Hydrogenotrophic archaea, gas liquid mass transfer, biomethane.

Suggested Citation

Giuliano, Antonio, Long-Term Ex-Situ Biological Methanation of Hydrogen and Carbon Dioxide Coupled to a Novel Gas Mass Transfer System Based on Controlled Hydrodynamic Cavitation. Available at SSRN: https://ssrn.com/abstract=4396157 or http://dx.doi.org/10.2139/ssrn.4396157

Antonio Giuliano (Contact Author)

Italian National Agency for New Technologies Energy and Sustainable Economic Development ( email )

Via Martiri di Monte Sole 4,
Bologna, BO 40129
Italy
+39 0516098458 (Phone)

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