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Título
Effect of operating pressure on direct biomethane production from carbon dioxide and exogenous hydrogen in the anaerobic digestion of sewage sludge
Autor
Año del Documento
2020
Editorial
Elsevier
Descripción
Producción Científica
Documento Fuente
Applied Energy, 2020, vol. 280, p. 115915
Resumo
The development of biological Power-to-Methane in-situ technologies aimed at producing biomethane directly in a single anaerobic digestion unit by the supply of external hydrogen, find its limiting step in the gas-to-liquid mass transfer of poorly soluble hydrogen. Increasing the operating pressure with an exogenous hydrogen supply could enhance transfer rates of hydrogen and carbon dioxide (enriching gas phase with methane) and simultaneously control the liquid media pH because the methanation of hydrogen and carbon dioxide prevents the acidification caused by carbon dioxide/bicarbonate equilibrium displacement. Thus, the feasibility of operating the anaerobic digestion of sludge at a pressure higher than the atmospheric pressure with an exogenous hydrogen supply to improve the solubilisation of hydrogen and subsequent bioconversion of hydrogen and carbon dioxide into methane by methanogenic archaea was studied. A mesophilic sludge digester (35 L) was operated at variable absolute pressure up to 300 kPa. Hydrogen was continuously supplied through the sludge recirculation stream, coupled to a static mixer. Hydrogen conversion increased with the operating pressure (up to 99%), and the methane concentration in the digester off-gas averaged 92.9 ± 2.3% at 300 kPa (maximum of 95.2%). pH approached 7 under such conditions, and the efficiency of organic matter removal was similar to that observed during conventional anaerobic digestion at atmospheric pressure without a detrimental accumulation of volatile fatty acids. This study confirmed that increasing the system pressure (mass transfer driving force) can be a viable alternative to high energy-consuming mixing methods to enhance the hydrogen gas-liquid mass transfer.
Materias Unesco
23 Química
33 Ciencias Tecnológicas
Palabras Clave
Biometano
Biomethane
Metanización de CO2
Digestión de lodos
Sludge digestion
Methanation of CO2
ISSN
0306-2619
Revisión por pares
SI
Patrocinador
Junta de Castilla y León, programa EU-FEDER (CLU 2017-09 y UIC 071)
Version del Editor
Propietario de los Derechos
© 2020 Elsevier
Idioma
eng
Tipo de versión
info:eu-repo/semantics/acceptedVersion
Derechos
openAccess
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