Integration of Membrane Contactors and Bioelectrochemical Systems for CO 2 Conversion to CH 4

Rubén Rodríguez-Alegre, Alba Ceballos-Escalera, Daniele Molognoni, Pau Bosch-Jimenez, David Galí, Edxon Licon, Monica Della Pirriera, Julia Garcia-Montaño and Eduard Borràs
Additional contact information
Rubén Rodríguez-Alegre: LEITAT Technological Center, C/ de la Innovació 2, 08225 Terrassa, Barcelona, Spain
Alba Ceballos-Escalera: LEITAT Technological Center, C/ de la Innovació 2, 08225 Terrassa, Barcelona, Spain
Daniele Molognoni: LEITAT Technological Center, C/ de la Innovació 2, 08225 Terrassa, Barcelona, Spain
Pau Bosch-Jimenez: LEITAT Technological Center, C/ de la Innovació 2, 08225 Terrassa, Barcelona, Spain
David Galí: LEITAT Technological Center, C/ de la Innovació 2, 08225 Terrassa, Barcelona, Spain
Edxon Licon: LEITAT Technological Center, C/ de la Innovació 2, 08225 Terrassa, Barcelona, Spain
Monica Della Pirriera: LEITAT Technological Center, C/ de la Innovació 2, 08225 Terrassa, Barcelona, Spain
Julia Garcia-Montaño: LEITAT Technological Center, C/ de la Innovació 2, 08225 Terrassa, Barcelona, Spain
Eduard Borràs: LEITAT Technological Center, C/ de la Innovació 2, 08225 Terrassa, Barcelona, Spain

Energies, 2019, vol. 12, issue 3, 1-19

Abstract: Anaerobic digestion of sewage sludge produces large amounts of CO 2 which contribute to global CO 2 emissions. Capture and conversion of CO 2 into valuable products is a novel way to reduce CO 2 emissions and valorize it. Membrane contactors can be used for CO 2 capture in liquid media, while bioelectrochemical systems (BES) can valorize dissolved CO 2 converting it to CH 4 , through electromethanogenesis (EMG). At the same time, EMG process, which requires electricity to drive the conversion, can be utilized to store electrical energy (eventually coming from renewables surplus) as methane. The study aims integrating the two technologies at a laboratory scale, using for the first time real wastewater as CO 2 capture medium. Five replicate EMG-BES cells were built and operated individually at 0.7 V. They were fed with both synthetic and real wastewater, saturated with CO 2 by membrane contactors. In a subsequent experimental step, four EMG-BES cells were electrical stacked in series while one was kept as reference. CH 4 production reached 4.6 L CH 4 m −2 d −1 , in line with available literature data, at a specific energy consumption of 16–18 kWh m −3 CH 4 (65% energy efficiency). Organic matter was removed from wastewater at approximately 80% efficiency. CO 2 conversion efficiency was limited (0.3–3.7%), depending on the amount of CO 2 injected in wastewater. Even though achieved performances are not yet competitive with other mature methanation technologies, key knowledge was gained on the integrated operation of membrane contactors and EMG-BES cells, setting the base for upscaling and future implementation of the technology.

Keywords: electromethanogenesis; energy storage; microbial electrochemical technology; methanogens; power to gas/fuel; renewable energy surplus (search for similar items in EconPapers)
JEL-codes: Q Q0 Q4 Q40 Q41 Q42 Q43 Q47 Q48 Q49 (search for similar items in EconPapers)
Date: 2019
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (2)

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