Biogas upgrading in a pilot-scale trickle bed reactor – Long-term biological methanation under real application conditions

• Published in: Bioresource technology 2023-05, Vol.376, p.128868-128868, Article 128868
• Main Authors: Feickert Fenske, Carolina, Kirzeder, Franz, Strübing, Dietmar, Koch, Konrad
• Format: Article
• Language: English
• Subjects: Biofuels; Biomethane; Bioreactors; Carbon Dioxide; Energy storage; Euryarchaeota; H2/CO2 methanation; Methane; Power-to-Gas; Technology; Upscaling
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2023.128868

[Display omitted] •Upscaling of trickle bed reactor to pilot-scale with 0.8 m3 reaction volume.•Technology integration on a wastewater treatment plant for biogas upgrading.•H2S in biogas of 200 ppm was reduced by half but additional sulfur source needed.•NH4+ concentration of over 400 mg/L most successful pH control strategy.•Stable long-term CH4 production of 6.1 m3/(m3RV·d) at synthetic natural gas quality. The biological methanation of H2 and CO2 in trickle bed reactors is one promising energy conversion technology for energy storage, but experiences at pilot-scale under real application conditions are still rare. Therefore, a trickle bed reactor with a reaction volume of 0.8 m3 was constructed and installed in a wastewater treatment plant to upgrade raw biogas from the local digester. The biogas H2S concentration of about200 ppm was reduced by half, but an artificial sulfur source was required to completely satisfy the sulfur demand of the methanogens. Increasing the ammonium concentration to > 400 mg/L was the most successful pH control strategy, enabling stable long-term biogas upgrading at a CH4 production of 6.1 m3/(m3RV·d) with synthetic natural gas quality (CH4 > 98%). The results of this study with a reactor operation period of nearly 450 days, including two shutdowns, represents an important step towards the necessary full-scale integration.