Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5476399 | Energy | 2017 | 31 Pages |
Abstract
Biomethanation by hydrogenotrophic methanogens has been proven as a potential process for managing renewable power intermittency and upgrading biogas. The present work aimed to enrich hydrogenotrophic methanogens under different mixing conditions (gas recycle vs. mechanical mixing) and temperatures (mesophilic vs. thermophilic conditions) for biogas upgrading. The synthetic gas (H2:CO2Â =Â 4:1) was fed to the reactor bottom at a hydrogen injection rate (HIR) of 1.6Â LÂ H2Â Lâ1Â dâ1. The gas recycle (100Â LÂ Lâ1Â dâ1) under thermophilic condition was found to be the most effective, reaching over 96% H2 conversion to CH4 within 15Â d of operation. Archaea community analysis performed by 454 pyrosequencing showed that the sequence of Methanosaeta sp. decreased while obligate-hydrogenotrophic methanogens increased: Methanoculleus chikugoensis (19.5%) and Methanothermococcus thermolithotrophicus (28.1%) under mesophilic and thermophilic condition, respectively. To the thermophilic enriched culture, the biogas produced from an up-flow anaerobic sludge blanket reactor with additional hydrogen (four times of CO2) was fed at various HIRs for 200Â d. As HIR increased, H2 consumption rate also increased with CO2 removal contained in the biogas. Up to an HIR increase to 19.2Â LÂ H2Â Lâ1Â dâ1, the high calorific biomethane (96% of CH4) could be obtained at gas recycle rate of 200Â LÂ Lâ1Â dâ1.
Related Topics
Physical Sciences and Engineering
Energy
Energy (General)
Authors
Yeo-Myeong Yun, Shihwu Sung, Seoktae Kang, Mi-Sun Kim, Dong-Hoon Kim,