Journal article
Biomethanation of Syngas by Enriched Mixed Anaerobic Consortia in Trickle Bed Reactors
Department of Chemical and Biochemical Engineering, Technical University of Denmark1
PROSYS - Process and Systems Engineering Centre, Department of Chemical and Biochemical Engineering, Technical University of Denmark2
CERE – Center for Energy Ressources Engineering, Department of Chemical and Biochemical Engineering, Technical University of Denmark3
PILOT PLANT, Department of Chemical and Biochemical Engineering, Technical University of Denmark4
Two identical trickle-bed reactor setups were designed and operated under mesophilic conditions and atmospheric pressure, without pH control, for the biomethanation of syngas consisted of 45% H2, 25% CO2, 20% CO and 10% CH4. The reactors were inoculated with mixed methanogenic microbial consortia formerly adapted to the gaseous mixture.
During the start-up of the reactors acetic acid accumulation in the liquid broth resulted in a pH decrease to levels unfavorable for methanogenic activity. This was corrected by introducing a strong phosphate buffer in the medium (K2HPO4/KH2PO4 : 87 mM/13 mM). Channeling phenomena observed across the trickle bed were eliminated by setting a high liquid recirculation rate (1600 l/lbed/d).
The reactors were operated for 294 days presenting minor deviations between them at the 24 extracted steady states and high cell retention even at a hydraulic retention time (HRT) of 3.7 days. At a gas residence time of 2.31 h and a HRT of 5.5 days the achieved CH4 productivity was 2 mmol/lbed/h with 93% H2 and 90% CO conversion efficiency and a 78% electron yield to CH4.
The conducted study verified that an enriched methanogenic microbial consortium can effectively convert syngas to CH4 in a trickle bed reactor under appropriate operational conditions.
Language: | English |
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Publisher: | Springer Netherlands |
Year: | 2020 |
Pages: | 495-512 |
ISSN: | 1877265x and 18772641 |
Types: | Journal article |
DOI: | 10.1007/s12649-019-00649-2 |
ORCIDs: | Asimakopoulos, Konstantinos , Gavala, Hariklia N. and Skiadas, Ioannis V. |