Recent progress on microbial electrosynthesis reactor designs and strategies to enhance the reactor performance

Scalability of the Microbial Electro-acetogenesis Process for Biogas Upgradation: Performance and Technoeconomic Assessment of a Liter-Scale System

“…For instance, a large distance between the cathode and anode electrodes leads to a higher internal resistance, affecting the input cell voltage. The electrode surface area to electrolyte ratio and membrane surface area to electrolyte ratio ratios are also remarkably low in this type of reactor . Moreover, the H-shaped reactor has a mixing dead zone near the membrane assembly.…”

“…Furthermore, this process (i.e., CO 2 to CH 4 conversion via MES) has been attempted in scaled-up systems with 20, 32, and 50 L reactor capacities. – The electro-acetogenesis process (i.e., CO 2 to acetic acid production) has been mostly tested for acetic acid production rather than methane content enhancement in biogas-fed systems. – We demonstrated this process for biogas upgradation in a proof-of-concept study with lab-scale reactors earlier . The H-shaped reactor design used in the earlier proof-of-concept study and commonly for MES experiments is not considered feasible for scale-up due to several limitations . For instance, a large distance between the cathode and anode electrodes leads to a higher internal resistance, affecting the input cell voltage.…”

“…26 The H-shaped reactor design used in the earlier proof-of-concept study and commonly for MES experiments is not considered feasible for scale-up due to several limitations. 27 For instance, a large distance between the cathode and anode electrodes leads to a higher internal resistance, affecting the input cell voltage. The electrode surface area to electrolyte ratio and membrane surface area to electrolyte ratio ratios are also remarkably low in this type of reactor.…”

“…The electrode surface area to electrolyte ratio and membrane surface area to electrolyte ratio ratios are also remarkably low in this type of reactor. 27 Moreover, the Hshaped reactor has a mixing dead zone near the membrane assembly. Considering long-term practical applications, such designs are also tricky to assemble and handle and are prone to leakage issues.…”

Novel electrochemical strategies for the microbial conversion of CO2 into biomass and volatile fatty acids using a fluid‐like bed electrode in a three‐phase reactor

“…Indeed, hydrogenotrophic microorganisms are capable of increasing the H 2 evolution rate on a cathode by maintaining low H 2 partial pressure by H 2 consumption (Philips, 2020 ). These processes have been investigated using different reactor configurations and designs (Bajracharya et al., 2022 ; Liu et al., 2023 ). The state of art includes H‐type reactors in which polarization is provided by photovoltaic energy (Nevin et al., 2010 ), concentric tubular reactors (Batlle‐Vilanova et al., 2017 ), modular stacked reactors, commonly known as sandwich configuration, (Blasco‐Gómez et al., 2021 ) three‐chamber MES reactors (Gildemyn et al., 2015 ), stirred tank reactors (Krieg et al., 2018 ), photo‐driven MES reactors for culturing purple phototrophic bacteria (PPB) (Manchon et al., 2022 ), bubble column reactors (Asimakopoulos et al., 2018 ; Enzmann et al., 2019 ), packed/fixed and moving bed reactor (Marshall et al., 2013 ; Vassilev et al., 2019 ), non‐electroconductive moving bed MES reactor (Cai et al., 2022 ) or gas diffusion reactors (Bajracharya et al., 2016 ).…”