Ex-situ biomethanation for CO2 valorization: State of the art, recent advances, challenges, and future prospective

Thapa, Ajay; Jo, Hongmok; Han, Uijeong; Cho, Si-Kyung

doi:10.1016/j.biotechadv.2023.108218

Cited by 15 publications

(9 citation statements)

References 104 publications

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“…At the end of phase (I), the concentration of suspended biomass dry weight reached approximately 1.5 g/L (The optical density at 600 nm, OD 600 = 2.7) [ 16 ]. The findings of this study in phase (I) within the TR were comparable in terms of the MPR to other studies using fixed or submerged reactors [ 6 , 13 ]. However, they still fall short of the reported high-performance continuous systems, such as trickle beds (15.4 , packed tubular (27 ) and cascade reactors (36 ) [ 16 , 34 , 35 ].…”

Section: Resultsmentioning

confidence: 99%

“…To the best of our knowledge, the highest reported laboratory-scale continuous BM’s MPR value exceeding 90% CH 4 concentration was achieved by a cascade packed column reactor (36 ) running for a limited duration of 37 h due to technical issues [ 35 ]. While some studies have reported higher values, they achieved this at the trade-off of methane concentration [ 6 , 13 ].…”

Section: Resultsmentioning

confidence: 99%

“…This process facilitated via the activity of hydrogen-consuming hydrogenotrophic methanogens in the BM process. This upgraded biogas, characterized by a high CH 4 content and low impurities, is known as biomethane and can be readily stored within the gas grid based on countries standards [ 5 ], making it a versatile energy source for various sectors [ 6 ].…”

Section: Introductionmentioning

confidence: 99%

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Improved biological methanation using tubular foam-bed reactor

Khesali Aghtaei,

Heyer,

Reichl

et al. 2024

Biotechnol Biofuels

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Background Power-to-gas is the pivotal link between electricity and gas infrastructure, enabling the broader integration of renewable energy. Yet, enhancements are necessary for its full potential. In the biomethanation process, transferring H2 into the liquid phase is a rate-limiting step. To address this, we developed a novel tubular foam-bed reactor (TFBR) and investigated its performance at laboratory scale. Results A non-ionic polymeric surfactant (Pluronic® F-68) at 1.5% w/v was added to the TFBR’s culture medium to generate a stabilized liquid foam structure. This increased both the gas–liquid surface area and the bubble retention time. Within the tubing, cells predominantly traveled evenly suspended in the liquid phase or were entrapped in the thin liquid film of bubbles flowing inside the tube. Phase (I) of the experiment focused primarily on mesophilic (40 °C) operation of the tubular reactor, followed by phase (II), when Pluronic® F-68 was added. In phase (II), the TFBR exhibited 6.5-fold increase in biomethane production rate (MPR) to 15.1 $$({\text{L}}_{{\text{CH}}_{4}}\text{/}{\text{L}}_{\text{R}}\text{/d)}$$ ( L CH 4 /L R /d) , with a CH4 concentration exceeding 90% (grid quality), suggesting improved H2 transfer. Transitioning to phase (III) with continuous operation at 55 °C, the MPR reached 29.7 $${\text{L}}_{{\text{CH}}_{4}}\text{/}{\text{L}}_{\text{R}}\text{/d}$$ L CH 4 /L R /d while maintaining the grid quality CH4. Despite, reduced gas–liquid solubility and gas–liquid mass transfer at higher temperatures, the twofold increase in MPR compared to phase (II) might be attributed to other factors, i.e., higher metabolic activity of the methanogenic archaea. To assess process robustness for phase (II) conditions, a partial H2 feeding regime (12 h 100% and 12 h 10% of the nominal feeding rate) was implemented. Results demonstrated a resilient MPR of approximately 14.8 $${\text{L}}_{{\text{CH}}_{4}}\text{/}{\text{L}}_{\text{R}}\text{/d}$$ L CH 4 /L R /d even with intermittent, low H2 concentration. Conclusions Overall, the TFBR’s performance plant sets the course for an accelerated introduction of biomethanation technology for the storage of volatile renewable energy. Robust process performance, even under H2 starvation, underscores its reliability. Further steps towards an optimum operation regime and scale-up should be initiated. Additionally, the use of TFBR systems should be considered for biotechnological processes in which gas–liquid mass transfer is a limiting factor for achieving higher reaction rates.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Improved biological methanation using tubular foam-bed reactor

Khesali Aghtaei,

Heyer,

Reichl

et al. 2024

Biotechnol Biofuels

View full text Add to dashboard Cite

show abstract

“…In addition, it can be used to upgrade biogas, utilizing CO 2 in excess combined to an external source of H 2 in ex situ technologies. 25 Among biological methanation systems described in the literature, 26,27 CSTR are the most commonly found. In most of the cases, H 2 diffusion in liquid media remains the major drawback and little information is available on the system efficiency and optimization.…”

Section: Discussionmentioning

confidence: 99%

“…In addition, it can be used to upgrade biogas, utilizing CO 2 in excess combined to an external source of H 2 in ex situ technologies. 25…”

Section: Discussionmentioning

confidence: 99%