Integration of gas-liquid membrane contactors into anaerobic digestion as a promising route to reduce uncontrolled greenhouse gas (CH4/CO2) emissions

Merve Visnyei; Péter Bakonyi; Katalin Bélafi-Bakó; Nándor Nemestóthy

doi:10.1016/j.biortech.2022.128072

Integration of gas-liquid membrane contactors into anaerobic digestion as a promising route to reduce uncontrolled greenhouse gas (CH₄/CO₂) emissions

Bioresour Technol. 2022 Nov:364:128072. doi: 10.1016/j.biortech.2022.128072. Epub 2022 Oct 10.

Authors

Merve Visnyei¹, Péter Bakonyi¹, Katalin Bélafi-Bakó², Nándor Nemestóthy¹

Affiliations

¹ Research Group on Bioengineering, Membrane Technology and Energetics, University of Pannonia, Egyetem u. 10, 8200 Veszprém, Hungary.
² Research Group on Bioengineering, Membrane Technology and Energetics, University of Pannonia, Egyetem u. 10, 8200 Veszprém, Hungary. Electronic address: bako@almos.uni-pannon.hu.

PMID: 36229009
DOI: 10.1016/j.biortech.2022.128072

Abstract

In this research, the recovery of dissolved biogas (CO₂/CH₄) from synthetic anaerobic effluents was studied using non-porous, polydimethylsiloxane (PDMS), hollow-fibre gas-liquid membrane contactors towards the design of a reduced carbon-footprint integrated bioprocess. As a key parameter, the gas-to-liquid (G/L) ratio (employing argon as sweep gas) was systematically varied in the range of 0.5-2.0. The results showed on a 1 m² PDMS module that increasing the liquid (effluent) flow rate favours the CH₄ transport, while a higher sweep gas flow rate is preferable for the CO₂ transport over CH₄. Depending on the actual biogas composition and the CO₂ content of the effluent, the methane recovery could be improved up to 63 % under steady-state conditions. In general, similar tendencies were observed when another PDMS membrane module with a smaller surface area (2 500 cm²) was applied hence, in this sense, the separation behaviour seems to be independent of the membrane size.

Keywords: Biogas recovery; Dissolved gases; Effluent treatment; Gas–liquid; Membrane separation; PDMS; Separation.