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In Situ High Pressure Hydrogen Tribological Testing of Common Polymer Materials Used in the Hydrogen Delivery Infrastructure
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Parameters affecting acetate concentrations during in-situ biological hydrogen methanation
Laura Mia Agneessens1, Lars Ditlev Mørck Ottosen1, Martin Andersen1
1Biological and Chemical Engineering, Aarhus University, Hangøvej 2, DK-8200 Aarhus N, Denmark.
Bioresource Technology
|March 10, 2018
Summary
Injecting hydrogen gas (H2) into anaerobic digesters can boost methane (CH4) but may cause acetate buildup. Key factors influencing this include organic loading rate, carbon dioxide (CO2) levels, and methanogen adaptation.
Area of Science:
- Environmental science
- Biotechnology
- Chemical engineering
Background:
- Hydrogen gas (H2) injection into anaerobic digesters is a strategy to enhance methane (CH4) yield from biogas.
- Acetate accumulation is a known issue following H2 addition, but the underlying factors are not fully understood.
Purpose of the Study:
- To investigate the parameters that control acetate accumulation during H2 injection for biogas upgrading.
- To elucidate the pathways of H2 consumption and acetate kinetics in anaerobic digestion.
Main Methods:
- Utilized continuous laboratory reactors and parallel batch 13C isotope tracing experiments.
- Quantified microbial populations, specifically Methanomicrobiales, using quantitative polymerase chain reaction (qPCR).
Main Results:
- Acetate accumulation intensified with increased organic loading rate and decreased CO2 concentrations (<7%) during initial H2 injections.
- Repeated H2 injections led to a higher CH4 share in H2 and 13C mass balances, correlating with increased Methanomicrobiales abundance.
Conclusions:
- Organic loading rate, inorganic carbon availability, and methanogen adaptation are critical determinants of acetate kinetics during H2 biomethanation.
- These parameters can form the basis for a predictive tool to manage acetate accumulation in anaerobic digesters during H2 enrichment.
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