Valorization of oat husk by hydrothermal carbonization: Optimization of process parameters and anaerobic digestion of spent liquors

Herman A. Murillo, Jhosané Pagés-Díaz, Luis A. Díaz-Robles*, Fidel Vallejo, César Huiliñir

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

17 Scopus citations

Abstract

The hydrothermal carbonization (HTC) optimization of oat husk was performed using a response surface methodology. Furthermore, anaerobic digestion (AD) of spent liquor and hydrochar addition were evaluated in the biomethane potential (BMP) test. Results found that temperature influences the most in the studied responses (i.e., mass yield (MY) and higher heating value (HHV)). Optimal hydrochar MY (53.8%) and HHV (21.5 MJ/kg) were obtained for 219.2 °C, 30 min, and 0.08 of biomass/water ratio. A successful prediction capability of the optimization approach was observed, archiving an error < 1% between predicted and validated responses. The BMP experiment showed the feasibility of spent liquor as a potential substrate to be treated by AD (144 NmLCH4/gCOD). Hydrochar boosted the methane production of spent liquor increasing up to 17% compared to digestion with no hydrochar addition. These findings provide new insights regarding oat husk valorization by integrating HTC and AD for energy production.

Original languageEnglish
Article number126112
JournalBioresource Technology
Volume343
DOIs
StatePublished - Jan 2022
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2021 Elsevier Ltd

Keywords

  • Anaerobic digestion
  • Hydrothermal carbonization
  • Oat husk
  • Process optimization
  • Spent liquors

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